JP6412694B2 - Electric vehicle and battery deterioration suppressing method thereof - Google Patents

Description

  The present invention relates to an electric vehicle that can be driven by electric power supplied from a battery to a driving motor and a method for suppressing battery deterioration thereof.

  Generally, a power storage device including a battery group (battery module) in which a plurality of batteries (storage batteries) are stacked is known. This power storage device is mounted on, for example, an electric vehicle such as a hybrid vehicle or an electric vehicle, and is configured to supply electric energy from a battery to a traveling motor so that the electric vehicle can travel.

  For this reason, it is necessary to ensure the reliability of the battery, and a device for suppressing the deterioration of the battery and improving the battery life is devised. Specifically, protection control of the battery is performed so that the target of the usable capacity of the battery can be secured within the warranty period (for example, warranty years) of the battery and within the guaranteed travel distance.

  For example, a battery charge / discharge control device disclosed in Patent Document 1 is known. In this battery charge / discharge control device, when the frequency at which the battery charge amount (SOC) (battery charge state) is located in the high SOC region exceeds a predetermined threshold, the control upper limit of the SOC is temporarily reduced.

  Therefore, the frequency at which the SOC is located in the high SOC region is reduced, so that an increase in battery temperature can be suppressed and a decrease in battery capacity can be prevented.

JP 2006-278132 A

  However, in an actual battery deterioration state, the battery deterioration is determined by the combination of the traveling years and the traveling distance of the electric vehicle. For this reason, in control by said patent document 1, it is necessary to perform control by distribution of each deterioration factor of a battery, and the frequency which suppression control intervenes increases significantly, and there exists a possibility that the use up of the said battery may be inhibited. . Moreover, in Patent Document 1, the guarantee period and the guaranteed mileage are not taken into consideration, and the actual battery capacity decreases below the required battery capacity before reaching the guarantee period or before reaching the guaranteed mileage. There is a case.

  The present invention solves this type of problem, and even when the warranty period and the guaranteed mileage are satisfied at the same time, the battery capacity can be secured satisfactorily and the battery can be used efficiently. It is an object of the present invention to provide an electric vehicle and a battery deterioration suppressing method thereof.

The present invention relates to an electric vehicle that can be driven by electric power supplied from a battery to a driving motor, and a battery deterioration suppressing method thereof. The electric vehicle includes a reference travel distance calculation unit, an average travel distance calculation unit, and a deterioration suppression control unit. The reference travel distance calculation unit calculates a reference travel distance during a predetermined period from the battery warranty period and the guaranteed travel distance, and the average travel distance calculation unit calculates an average travel distance during the predetermined period. The deterioration suppression control unit performs control to suppress battery deterioration when it is determined that the calculated average travel distance is the reference travel distance. Incidentally, when it is determined not to be the reference travel distance, in some cases, it can not perform control for suppressing deterioration of the battery.

  In this electric vehicle, the reference travel distance is set to a travel distance range including a predetermined range with a travel distance calculated from the guarantee period and the guarantee travel distance. Therefore, it is preferable to perform control for suppressing deterioration of the battery when the average travel distance falls within the travel distance range.

  Further, in this electric vehicle, the deterioration suppression control unit is configured to perform control for reducing the usable capacity of the battery, control for reducing the upper limit of the charging rate of the battery, control for reducing the cooling start temperature of the battery, or maximum control of the battery. It is preferable to perform at least one control for reducing the allowable current.

  Furthermore, in this electric vehicle, the predetermined period is preferably in units of one day.

  Further, in this electric vehicle, the deterioration suppression control unit may include a first map that performs control to suppress battery deterioration from the relationship between the guaranteed capacity and time when the average travel distance is smaller than the reference travel distance. preferable. It is preferable that the deterioration suppression control unit includes a second map that performs control for suppressing deterioration of the battery from the relationship between the guaranteed capacity and the travel distance when the average travel distance is larger than the reference travel distance. Then, when the average travel distance is the reference travel distance, control is performed to suppress the deterioration of the battery based on the larger difference between the guaranteed capacity and the actual capacity between the first map and the second map. Is preferred.

Further, the battery deterioration suppression method includes a step of calculating a reference travel distance during a predetermined period from the battery warranty period and the guaranteed travel distance, and a step of calculating an average travel distance during the predetermined period. This battery deterioration suppression method performs control for suppressing battery deterioration only when the average travel distance and the reference travel distance are compared and when the average travel distance is determined to be the reference travel distance. A deterioration suppressing step.

  According to the present invention, the reference travel distance calculated from the battery warranty period and the safe travel distance is compared with the average travel distance by actual travel. Here, if the average mileage is less than the reference mileage, the guarantee period elapses before reaching the guarantee mileage, so the neglected time (elapsed years) becomes dominant. On the other hand, when the average travel distance exceeds the reference travel distance, the actual travel distance becomes dominant because the safe travel distance is reached before the warranty period elapses.

  If the travel distance is the reference travel distance, both the guarantee period and the guarantee travel distance reach at the same time, so it is necessary to consider degradation due to neglected time and degradation due to travel distance. Therefore, the battery capacity can be secured to a certain amount by performing control for suppressing deterioration of the battery under such severe use conditions.

  Thereby, even when the guarantee period and the guarantee travel distance are satisfied at the same time, the battery capacity can be secured satisfactorily, and the battery can be used efficiently.

It is control block explanatory drawing of the electric vehicle which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the battery degradation suppression method which concerns on 1st Embodiment. It is control block explanatory drawing of the electric vehicle which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the 1st map which consists of a relationship between a capacity | capacitance and time (years). It is explanatory drawing of the 2nd map which consists of the relationship between a capacity | capacitance and a travel distance. It is a flowchart explaining the battery deterioration suppression method which concerns on 2nd Embodiment.

  As shown in FIG. 1, the electric vehicle 10 according to the first embodiment of the present invention is a battery-equipped vehicle such as a hybrid vehicle or an electric vehicle. The electric vehicle 10 can travel with electric power supplied from the drive storage battery (battery) 12 to the travel motor 14.

  While the driving storage battery 12 is discharged to the traveling motor 14, regenerative power is supplied (charged) from the traveling motor 14 to the driving storage battery 12. The drive storage battery 12 is provided with a temperature sensor 16 that detects the storage battery temperature, a voltage sensor 18 that detects the output voltage, and a current sensor 20 that detects the output current.

  The electric vehicle 10 includes a control device 22. The control device 22 includes a limit value setting unit 24 and a charge / discharge control unit 26. The limit value setting unit 24 includes an average travel distance calculating unit (average travel distance calculation unit) 30 connected to a travel distance meter 28 that measures the actual travel distance (actual travel distance) of the electric vehicle 10. The average travel distance calculating unit 30 calculates, for example, an average travel distance for a day during a predetermined period. Note that the predetermined period is not limited to one day, and can be set to, for example, one week, ten days, or one month.

  The average travel distance calculation unit 30 sends the calculated average travel distance to the limit value selection unit 32. The limit value selection means 32 is connected to a first memory 34 that stores a normal limit value (map) and a second memory 36 that stores a deterioration limit value (map). As will be described later, the normal limit value is used when the average travel distance is different from the reference travel distance, while the deterioration limit value is used when the average travel distance is the reference travel distance.

  The normal limit value and the deterioration limit value are the usable capacity of the drive storage battery 12, the upper limit of the charging rate of the drive storage battery 12, the cooling start temperature of the drive storage battery 12, and the maximum allowable current of the drive storage battery 12, respectively. Have.

  For example, the normal limit value is set such that the usable capacity is 2 Ah, the charging rate is 90%, the cooling start temperature is 60 ° C., and the maximum allowable current is 500 A. On the other hand, the deterioration limit value is set such that, for example, the usable capacity is 1 Ah, the charging rate is 70%, the cooling start temperature is 25 ° C., and the maximum allowable current is 200 A. The deterioration limit value only needs to be set to a value stricter than the normal limit value, and each numerical value can be variously changed.

  The limit value selection means 32 is connected to a reference travel distance calculation means (reference travel distance calculation unit) 38. The reference mileage calculation means 38 calculates a reference mileage during a predetermined period from the guaranteed period and the guaranteed mileage of the drive battery 12. For example, if the guarantee period is 10 years and the guaranteed mileage is 200,000 km, the reference mileage per day during the predetermined period is 55 km (200000 km / 3650 days), for example. The reference travel distance is set to a travel distance range that includes a predetermined range with the daily reference travel distance in between, for example, 50 km ≦ reference travel distance ≦ 60 km.

  A charge / discharge control unit 26 is connected to the limit value selection means 32, and the charge / discharge control unit 26 sends a control command to the traveling motor 14. The charge / discharge control unit 26 functions as a deterioration suppression control unit (deterioration suppression control unit) 40. When it is determined that the calculated average travel distance is the reference travel distance (within the travel distance range), the deterioration suppression control unit 40 performs control to suppress the deterioration of the drive storage battery 12 along the deterioration limit value.

  The operation of the electric vehicle 10 configured as described above will be described below along the flowchart shown in FIG. 2 in relation to the battery deterioration suppressing method according to the first embodiment.

  First, the reference travel distance calculation means 38 calculates a reference travel distance for one day from the guaranteed period and the guaranteed travel distance of the drive storage battery 12 (step S1). In the first embodiment, the guarantee period is 10 years, the guaranteed mileage is 200,000 km, and the daily reference mileage is 55 km. The reference travel distance is set in a range of 50 km ≦ reference travel distance ≦ 60 km.

  Next, proceeding to step S2, the average mileage calculating means 30 calculates the average mileage per day by dividing the cumulative mileage obtained from the odometer 28 by a predetermined number of days. Furthermore, it progresses to step S3 and an average traveling distance and a reference traveling distance are compared.

  If it is determined that the average travel distance is not the reference travel distance (NO in step S3), the process proceeds to step S4, and control is performed using the normal limit value. Here, when the average travel distance is less than the reference travel distance (average travel distance <50 km), the guarantee period elapses before the actual travel distance reaches the guarantee travel distance, and therefore the neglected time becomes dominant. On the other hand, when the average travel distance is a value exceeding the reference travel distance (60 Km <average travel distance), the travel distance is dominant because the travel distance reaches the secure travel distance before the warranty period elapses.

  For this reason, in step S4, the usable capacity of the drive storage battery 12 is set to a predetermined value Swh. Specifically, it is a normal limit value, for example, the usable capacity is set to 2 Ah, the charging rate is set to 90%, the cooling start temperature is set to 60 ° C., and the maximum allowable current is set to 500 A. Therefore, the capacity of the drive storage battery 12 can be used up when the guarantee period is reached or when the guarantee travel distance is reached.

  If it is determined that the average travel distance is the reference travel distance (YES in step S3), the process proceeds to step S5, and the usable capacity of the drive storage battery 12 is set to a predetermined value Twh (<predetermined value Swh). It is set and control is performed using the deterioration limit value. Since both the guarantee period and the guaranteed travel distance reach at the same time, deterioration due to neglected time and deterioration due to travel distance must be taken into account, and severe use conditions are set. Specifically, for example, the degradation limit value is set such that the usable capacity is 1 Ah, the charging rate is 70%, the cooling start temperature is 25 ° C., and the maximum allowable current is 200 A.

  Thereby, control which suppresses deterioration of the drive storage battery 12 is performed under severe use conditions, the capacity of the drive storage battery 12 can be ensured to a certain amount, and the performance (capacity) of the drive storage battery 12 can be secured. Can be used up.

  For this reason, in the first embodiment, even when the guarantee period and the guarantee travel distance are satisfied at the same time, the battery capacity can be secured satisfactorily, and the drive storage battery 12 can be used efficiently. An effect is obtained.

  FIG. 3 is an explanatory diagram of the control block of the electric vehicle 50 according to the second embodiment of the present invention. The same components as those of the electric vehicle 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The electric vehicle 50 includes a control device 52. The limit value setting unit 54 constituting the control device 52 includes a second memory 36a that stores a first deterioration limit value and a third memory 36b that stores a second deterioration limit value.

  The first deterioration limit value is a limit value when the average travel distance is less than the reference travel distance (average travel distance <50 Km). As shown in FIG. 4, the first deterioration limit value includes a relationship between capacity and time (years). One reference capacitor F1 (first map) is included. The second deterioration limit value is a limit value when the average travel distance exceeds the reference travel distance (60 Km <average travel distance), and as shown in FIG. 2 has a reference capacitance F2 (second map).

  The control device 52 includes a real capacity detection unit 56 connected to the limit value selection unit 32. The actual capacity detecting means 56 detects the actual capacity of the drive storage battery 12 and can be calculated by a known method. For example, it is calculated from (capacity of the new drive storage battery 12) × (current internal resistance of the drive storage battery 12) ÷ (internal resistance of the new drive storage battery 12). Alternatively, the actual capacity may be calculated by fully discharging the drive storage battery 12 and then calculating the discharge capacity at that time. A temperature sensor 16, a voltage sensor 18, and a current sensor 20 are connected to the actual capacity detection unit 56.

  The operation of the electric vehicle 50 configured as described above will be described below along the flowchart shown in FIG. 6 in relation to the battery deterioration suppressing method according to the second embodiment.

  First, after calculating the daily reference travel distance from the warranty period and the guaranteed travel distance of the drive storage battery 12 (step S10), the average daily travel distance is calculated (step S11). Furthermore, in step S <b> 12, the actual capacity of the driving storage battery 12 is calculated by the actual capacity detection unit 56.

  In step S13, the average travel distance is compared with the reference travel distance, and if it is determined that the average travel distance is the reference travel distance (YES in step S13), the process proceeds to step S14. In step S14, the actual capacity is compared with the first reference capacity F1 and the second reference capacity F2. If it is determined that the actual capacity exceeds (exceeds) both the first reference capacity F1 and the second reference capacity F2 (YES in step S14), the process proceeds to step S15, and control is performed according to the normal limit value. .

  On the other hand, if it is determined that the actual capacity is at least either the first reference capacity F1 or less or the second reference capacity F2 or less (NO in step S14), the process proceeds to step S16. In step S16, it is determined whether or not the difference between the first reference capacity F1 and the actual capacity is smaller than the difference between the second reference capacity F2 and the actual capacity.

  If it is determined that the difference between the first reference capacity F1 and the actual capacity is smaller than the difference between the second reference capacity F2 and the actual capacity (YES in step S16), the process proceeds to step S17, and the second deterioration Control by the limit value is performed. In other words, the control is performed based on the second map (see FIG. 5) including the relationship between the capacity and the travel distance on the side with the larger difference. Here, the second deterioration limit value is determined based on the magnitude of the difference between the second reference capacity F2 and the actual capacity at the current travel distance. That is, the larger the difference is, the more the usable capacity, the charging rate, the cooling start temperature, and the maximum allowable current are set to be more restricted. This setting can be dealt with by preparing a map showing the relationship between the difference and the limit amount in advance through experiments or the like.

  When it is determined that the difference between the first reference capacity F1 and the actual capacity is equal to or greater than the difference between the second reference capacity F2 and the actual capacity (NO in step S16), the process proceeds to step S18. Control by 1 degradation limit value is performed. In other words, the control is performed based on the first map (see FIG. 4) including the relationship between the capacity and the time on the side of the larger difference. Here, the first deterioration limit value is determined based on the magnitude of the difference between the first reference capacity F1 and the actual capacity at the current elapsed time. That is, the larger the difference is, the more the usable capacity, the charging rate, the cooling start temperature, and the maximum allowable current are set to be more restricted. This setting can be dealt with by preparing a map showing the relationship between the difference and the limit amount in advance through experiments or the like.

  Furthermore, when it is determined in step S13 that the average travel distance is less than the reference travel distance (average travel distance <50 km), the process proceeds to step S19, and whether or not the actual capacity exceeds the first reference capacity F1. To be judged. If it is determined that the actual capacity exceeds the first reference capacity F1 (YES in step S19), the process proceeds to step S15 and is controlled along the normal limit value. On the other hand, when it is determined that the actual capacity is equal to or less than the first reference capacity F1 (NO in step S19), the process proceeds to step S18 and is controlled along the first deterioration limit value (first map).

  Further, when it is determined in step S13 that the average mileage is a value exceeding the reference mileage (60 Km <average mileage), the process proceeds to step S20, and whether or not the actual capacity exceeds the second reference capacity F2. Is judged. If it is determined that the actual capacity exceeds the second reference capacity F2 (YES in step S20), the process proceeds to step S15 and is controlled along the normal limit value. On the other hand, when it is determined that the actual capacity is equal to or less than the second reference capacity F2 (NO in step S20), the process proceeds to step S17 and is controlled along the second deterioration limit value (second map).

  Thus, in the second embodiment, even when the guarantee period and the guarantee travel distance are satisfied at the same time, the battery capacity can be secured satisfactorily, and the drive storage battery 12 can be used efficiently. The same effects as those of the first embodiment are obtained. In addition, when the guarantee period and the guarantee travel distance are satisfied at the same time, the larger (stricter) difference between the first deterioration limit value and the second deterioration limit value is selected. For this reason, there exists an advantage that the capacity control of the storage battery 12 for a drive is performed more reliably.

  In addition, if it is determined that the average travel distance is less than the reference travel distance, the limit value is changed to the first deterioration limit value, while the average travel distance is determined to be a value exceeding the reference travel distance. Then, the limit value is changed to the second deterioration limit value. Therefore, even when the average mileage deviates from the reference mileage, the deterioration suppression control is performed. In such a case, the battery capacity can be ensured satisfactorily.

DESCRIPTION OF SYMBOLS 10, 50 ... Electric vehicle 12 ... Drive battery 14 ... Driving motor 16 ... Temperature sensor 18 ... Voltage sensor 20 ... Current sensor 26 ... Charge / discharge control part 28 ... Odometer 30 ... Average mileage calculation means 32 ... Limit value Selection means 34, 36 ... Memory 38 ... Reference travel distance calculation means 40 ... Deterioration suppression control means 52 ... Control device 54 ... Limit value setting unit 56 ... Actual capacity detection means

Claims (6)

An electric vehicle capable of traveling with electric power supplied from a battery to a traveling motor,
A reference mileage calculation unit for calculating a reference mileage during a predetermined period from the warranty period and the guaranteed mileage of the battery;
An average mileage calculating unit for calculating an average mileage during the predetermined period;
When it is determined that the calculated average travel distance is the reference travel distance, control is performed to suppress deterioration of the battery, while when it is determined that the average travel distance is not the reference travel distance, deterioration of the battery is suppressed. A deterioration suppression control unit that does not perform control;
An electric vehicle comprising: The electric vehicle according to claim 1, wherein the reference travel distance is set to a travel distance range including a predetermined range across a travel distance calculated from the guarantee period and the guarantee travel distance,
When the average travel distance falls within the travel distance range, control for suppressing deterioration of the battery is performed.   3. The electric vehicle according to claim 1, wherein the deterioration suppression control unit is configured to reduce a usable capacity of the battery, control to reduce an upper limit of the charging rate of the battery, and lower a cooling start temperature of the battery. An electric vehicle characterized by performing at least one of control or control for reducing the maximum allowable current of the battery.   The electric vehicle according to claim 1, wherein the predetermined period is in units of one day. An electric vehicle capable of traveling with electric power supplied from a battery to a traveling motor,
A reference mileage calculation unit for calculating a reference mileage during a predetermined period from the warranty period and the guaranteed mileage of the battery;
An average mileage calculating unit for calculating an average mileage during the predetermined period;
A deterioration suppression control unit that performs control to suppress deterioration of the battery when the calculated average travel distance is determined to be the reference travel distance;
With
The deterioration suppression control unit, when the average travel distance is smaller than the reference travel distance, a first map that performs control to suppress the deterioration of the battery from the relationship between the guaranteed capacity and time;
A second map that performs control to suppress deterioration of the battery from the relationship between the guaranteed capacity and the travel distance when the average travel distance is greater than the reference travel distance;
And having
When the average travel distance is the reference travel distance, a control for suppressing deterioration of the battery based on a larger difference between the guaranteed capacity and the actual capacity between the first map and the second map. The electric vehicle characterized by performing. A battery deterioration suppression method for an electric vehicle capable of running with electric power supplied from a battery to a running motor,
Calculating a reference mileage during a predetermined period from the warranty period and the guaranteed mileage of the battery;
Calculating an average mileage during the predetermined period;
Comparing the average mileage and the reference mileage;
Only when it is determined that the average mileage is the reference mileage, a deterioration suppressing step of performing control for suppressing deterioration of the battery,
A battery deterioration suppressing method for an electric vehicle characterized by comprising:

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