JP2015065716A - Charge control device, vehicle having the same, and charge control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge control device, capable of sufficiently exhibiting battery performance if an assumed battery is mounted, and capable of suppressing early battery deterioration even if a battery different from the assumed battery is mounted.SOLUTION: The charge control device includes: deterioration state determination means 60 and 30 for determining that a battery 20 is deteriorated when a parameter indicative of the deterioration state of the battery 20 exceeds a preset specified value; charge amount detection means 60 and 50 for detecting the charge amount of the battery 20; and charge amount management means 30 for controlling, when the deterioration state determination means 60 and 30 determine that the battery 20 is deteriorated, to charge and discharge the battery 20 in a manner to increase a charge amount as compared to a case where the deterioration state determination means 60 and 30 do not determine that the battery 20 is deteriorated.

Description

The present invention relates to a charging control device such as a battery mounted on a vehicle.

  Conventionally, an SOC (State Of Charge) indicating the state of charge of a battery is calculated, it is determined whether the calculated SOC is larger than a predetermined threshold value, and the generated voltage of the alternator is controlled based on the determination result (See Patent Document 1).

JP 2012-186908 A

  In the charge control device described in Patent Literature 1, when a battery different from the assumed battery is mounted, charging and discharging are performed so that the SOC is higher than the recommended SOC, thereby sufficiently improving the performance of the battery. When the battery cannot be used or when the charge / discharge control is performed so that the SOC is lower than the recommended SOC, the battery may be deteriorated at an early stage.

  The present invention has been made in order to solve the above-described problems, and its main purpose is to enable the battery performance to be sufficiently exerted when the assumed battery is mounted, and is assumed. An object of the present invention is to provide a charge control device capable of suppressing early deterioration of a battery even when a battery different from the existing battery is mounted.

  The present invention is a charge control device, a deterioration state determination means for determining that a battery has deteriorated when a parameter indicating the deterioration state of the battery exceeds a predetermined value, and a capacity for detecting the capacity of the battery When it is determined that the battery has deteriorated by the detection means and the deterioration state determination means, the battery is charged / discharged so that the capacity increases compared to the case where the deterioration state determination means does not determine that the battery has deteriorated. And capacity management means for controlling the above.

  Further, the present invention is a battery charge control method executed by the charge control device, wherein determination is made that the battery is deteriorated when a parameter indicating a deterioration state of the battery exceeds a predetermined value. A step of detecting a capacity of the battery, and a step of determining if the battery has deteriorated in the determination step, compared with a case where the battery is not determined to have deteriorated in the determination step. And a control step for controlling charging / discharging of the battery.

  According to the above invention, when the battery is not deteriorated, charge / discharge control is performed in a state where the capacity is small compared to the deteriorated state, and when the battery is deteriorated, the battery is not deteriorated. Charge / discharge control is performed in a state where the capacity is larger than that in the state. For this reason, in the state in which the assumed battery is mounted and the battery is not deteriorated, the free capacity of the battery and the charging current at the time of charging are increased, and the battery performance can be sufficiently exhibited. On the other hand, when a battery different from the assumed battery is installed and the battery is deteriorated early, charge / discharge control is performed in a state where the capacity is large compared to a state where the battery is not deteriorated. Further rapid deterioration can be suppressed.

Electrical block diagram according to the embodiment The figure which shows the change of the starting lower limit voltage due to the deterioration of the battery Correlation diagram between battery capacity and charging current Time chart of AGM mode Time chart in Pb mode The figure which shows the lifetime of the battery at the time of applying embodiment

  The charge control device according to the present embodiment is mounted on a vehicle using an engine, which is an internal combustion engine, as a travel drive source, and a battery is charged by an alternator. The vehicle has an idling stop function that automatically stops the engine when a predetermined automatic stop condition is satisfied, and automatically restarts the engine when a predetermined automatic restart condition is satisfied.

  As shown in FIG. 1, the vehicle 100 is provided with an engine 1, an alternator 10 that converts the output of the engine 1 into electric power, a battery 20 that supplies electric power to various electric loads provided in the vehicle 100, and the vehicle 100. An ECU 30 that controls various devices, a starter motor 40 that starts the engine 1 with the electric power of the battery 20, a voltmeter 60 that measures the voltage of the battery 20, and the like are provided. Between the alternator 10 and the battery 20, an ammeter 50 for measuring charge / discharge current is provided. The alternator 10 is provided with a regulator 11 that adjusts the voltage. When the ECU 30 transmits a voltage control signal to the regulator 11, the voltage of the alternator 10 is changed.

  As the battery 20, it is assumed that an AGM (Absorbed Glass Mat) battery (second battery) is mounted. An AGM battery is a battery in which an electrolyte is absorbed in a glass fiber mat and the mat is used as a separator. The AGM battery has a longer life compared to the Pb battery (first battery), and even if charging and discharging are repeated in a state where the capacity is about 70 to 80%, unlike the Pb battery, it does not cause rapid deterioration. Few.

  On the other hand, it is recommended that the Pb battery be repeatedly charged and discharged in a state where the capacity is 90% or more. For example, when the charge and discharge is repeated at a capacity of about 70 to 80% as in the AGM battery, Will need to be replaced early. Therefore, when a Pb battery is mounted on the vehicle 100 that is assumed to be mounted with an AGM battery and is repeatedly charged and discharged with a capacity of about 70 to 80%, the Pb battery may rapidly deteriorate.

  Next, the deterioration of the battery 20 and the starting lower limit voltage will be described with reference to FIGS. 2 (a) and 2 (b). The vertical axis represents the starting lower limit voltage at which the voltage of the battery 20 dropped most when the engine 1 was started, and the horizontal axis represents time. As the internal resistance of the battery 20 increases as the battery 20 deteriorates, the voltage drop increases and the starting lower limit voltage decreases. If the starting lower limit voltage is 7.2 V or less, the engine 1 cannot be started, and the battery 20 must be replaced. The voltmeter 60 and the ECU 30 constitute a deterioration state determination unit.

  FIG. 2A shows a change in the starting lower limit voltage when charge / discharge control is performed so that the capacity is 90% in the vehicle 100 in which the Pb battery is assumed to be mounted. On the other hand, FIG. 2B shows a change in the starting lower limit voltage when charge / discharge control is performed so that the capacity becomes 75% in the vehicle 100 assumed to be mounted with an AGM battery. As shown in FIG. 2B, when a Pb battery is erroneously mounted instead of the AGM battery, charge / discharge control is performed so that the capacity of the Pb battery is 75%. As a result, the Pb battery rapidly deteriorates and needs to be replaced early.

  Here, the relationship between the capacity of the battery 20 and the charging current will be described with reference to FIG. The vertical axis in FIG. 3 represents the charging current, and the horizontal axis represents the capacity. The characteristics of the charging current with respect to the capacity of the battery 20 are the same between the AGM battery and the Pb battery. As is clear from FIG. 3, if charging is performed in a state where the capacity of the battery 20 is small, the charging current can be increased and a large amount of power can be charged in the battery 20 in a short time. That is, for example, when charge / discharge control is performed so that the capacity is 75%, for example, charge current during regenerative power generation is compared with when charge / discharge control is performed so that the capacity is 90%. The energy generated during regeneration can be used for charging the battery 20 more efficiently. The relationship between the charging current and the capacity is stored in a memory in the ECU 30.

  In the present embodiment, the ECU 30 functions as target value setting means so that the capacity of the AGM battery is 75%, and charge / discharge control is performed by setting the capacity management target value to 75% (second recommended capacity). Switching between the AGM mode and the Pb mode in which charge / discharge is performed by setting the capacity management target value to 90% (first recommended capacity) so that the capacity of the Pb battery is 90%. When the vehicle 100 is shipped, the AGM mode is set as an initial state. Further, when the battery 20 is replaced, the setting is reset and the AGM mode is set again. The set mode is stored in a memory in the ECU 30.

  First, when the engine 1 is started by the driver, the ECU 30 is activated, and the voltmeter 60 measures the starting lower limit voltage. Then, the deterioration determination of the battery 20 is performed by determining whether or not the starting lower limit voltage that is a parameter indicating the deterioration state of the battery 20 has become equal to or less than a predetermined value. If it is not determined that the starting lower limit voltage is equal to or lower than the predetermined value, the setting of the AGM mode is maintained. On the other hand, when it is determined that the starting lower limit voltage is equal to or lower than the predetermined value, the mode is changed to the Pb mode, and the mode stored in the memory in the ECU 30 is rewritten to the Pb mode. The stored mode is not changed until the battery 20 is replaced. After the Pb mode is set, the deterioration determination of the battery 20 is not performed.

  First, the AGM mode will be described with reference to FIG. In the AGM mode, charge / discharge control is performed so that the capacity of the battery 20 is 75%. As described above, the relationship between the capacity of the battery 20 and the charging current is stored in the ECU 30. Therefore, the ammeter 50 and the ECU 30 constitute capacity detection means, and the capacity of the battery 20 is obtained from the charging current measured by the ammeter 50. The charge / discharge control is performed by the ECU 30 functioning as a capacity management unit and changing the voltage of the alternator 10 by the regulator 11. Specifically, if the voltage of the alternator 10 exceeds the voltage of the battery 20, charging from the alternator 10 to the battery 20 is performed, and if the voltage of the alternator 10 falls below the voltage of the battery 20, discharging from the battery 20 is performed.

  In the AGM mode, after the engine 1 is started by the driver, charging / discharging control is not performed until the charging current reaches 20 A (second current value), and the voltage of the alternator 10 is maintained at the maximum voltage. That is, after the engine 1 is started at t0, t0 to t1 are in an idling state of the engine 1, acceleration is performed from t1 to t2, and steady running is performed in which t2 to t3 are maintained in a constant accelerator state. However, the applied voltage is constant. Then, at t3, when the charging current reaches 20A, charge / discharge control is started. Here, 20A is a charging current when the capacity of the AGM battery is 80%. As described above, since the relationship between the capacity of the battery 20 and the charging current is defined and stored in advance, the charging current of the battery 20 can be increased when the charging current is 20 A regardless of whether or not the Pb battery is mounted. The capacity is assumed to be 80%. And it determines that the capacity | capacitance of the battery 20 is 80%, and charging / discharging control is started.

  Note that at t3, the capacity is determined to be 80%, and idling stop (IS) control is also started. This may result in overdischarge when idling stop is performed when the charging current is large, that is, when the capacity of the battery 20 is small, and the engine 1 may not be restarted after performing idling stop control. Because there is.

  In steady running where the accelerator is kept in a constant state at t3 to t4, t5 to t6, and t9 to t10, the capacity maintenance control is performed so that the capacity becomes the target value. In other words, when the capacity exceeds the capacity management target value, the voltage applied from the alternator 10 to the battery 20 is lowered from a predetermined voltage (for example, 12.6 V) to discharge the battery 20. On the other hand, when the capacity falls below the capacity management target value, the voltage applied from the alternator 10 to the battery 20 is increased above a predetermined voltage to charge the battery 20. The capacity of the battery 20 is calculated based on the capacity of the battery 20 determined at t3 and the charge / discharge current of the battery 20. Note that the voltage is changed at a predetermined voltage drop rate −ΔV and a voltage rise rate ΔV.

  In t4 to t5 and t8 to t9, when the accelerator is depressed and accelerated by the driver, suppression control is performed. In the suppression control, the voltage of the alternator 10 is set to the lower limit regardless of the capacity of the battery 20, and the battery 20 is discharged.

  In t6 to t7 and t10 to t11, when the driver depresses the brake and decelerates, regeneration control is performed. In the regeneration control, the voltage of the alternator 10 is set to the upper limit regardless of the capacity of the battery 20, and the battery 20 is charged. At this time, since the charging current increases as the capacity decreases, it is possible to charge the battery 20 with more power if regeneration control is performed in a state where the capacity is small.

  When the vehicle 100 stops at t7, the engine 1 is automatically stopped by idling stop (IS) control, and suppression control is performed until t8 when the engine 1 is restarted. In the suppression control during idling stop, the voltage of the alternator 10 is set to the lower limit regardless of the capacity (the power generation by the alternator 10 is stopped), similarly to the suppression control during acceleration.

  Next, the Pb mode will be described with reference to FIG.

  In the Pb mode, unlike the AGM mode, charge / discharge control is performed so that the capacity of the battery 20 is 90%.

  In the Pb mode, after the engine 1 is started by the driver, the charging / discharging control is not performed until the charging current reaches 7.5 A (first current value), and the voltage of the alternator 10 is maintained at the maximum voltage. That is, after the engine 1 is started at t0 ′, t0 ′ to t1 ′ are in an idling state, t1 ′ to t2 ′ are accelerated, t2 ′ to t3 ′ are steady running, but the voltage is It is constant. Then, when the charging current becomes 7.5 A at t3 ′, the charge / discharge control is started. Here, 7.5 A is a charging current when the capacity of the Pb battery is 95%. As described above, since the relationship between the capacity of the battery 20 and the charging current is defined and stored in advance, the battery is charged if the charging current becomes 7.5 A regardless of whether or not the Pb battery is mounted. The 20 capacity is assumed to be 95%. And it determines that the capacity | capacitance of the battery 20 is 95%, and charging / discharging control is started. Similar to the AGM mode, the capacity of the battery 20 is determined to be 95% at t3 ′, and the idling stop control is also started.

  From t3 ′ to t11 ′, the same control as the control from t3 to t11 in the AGM mode described above is performed. In the regeneration control at t6 ′ to t7 ′ and t10 ′ to t11 ′, the applied voltage is set to the upper limit value as in the AGM mode, but the value of the charging current is smaller than that in the AGM mode. This is because the capacity management target value is set higher in the Pb mode than in the AGM mode.

  As described above, the AGM mode is executed when it is determined that the battery 20 has not deteriorated, and the Pb mode is executed when it is determined that the battery 20 has deteriorated. With reference to FIG. 6, the relationship between the mode switching and the starting lower limit voltage will be described in the case where the AGM battery is replaced with the Pb battery.

  First, when the vehicle 100 is shipped, an AGM battery is mounted, and the mode is set to the AGM mode. If the AGM battery is deteriorated by using the vehicle 100 for a predetermined period and the starting lower limit voltage is equal to or lower than the predetermined value, the mode is switched and the Pb mode is set. Further, when the vehicle 100 is further used and the deterioration of the AGM battery progresses and the lower limit voltage at the time of start falls below 7.2 V, the start of the engine 1 becomes difficult, so the battery 20 is replaced. As described above, in the Pb mode, charge / discharge control is performed with a higher capacity management target value than in the AGM mode. Therefore, the life of the AGM battery is extended as compared with the case where charge / discharge control is performed only in the AGM mode.

  Here, it is assumed that a Pb battery is mounted instead of the AGM battery recommended for mounting when the battery 20 is replaced. With the replacement of the battery 20, the mode is set to the AGM mode, and charge / discharge control is performed at a capacity management target value lower than the recommended capacity of the Pb battery. As a result, the Pb battery rapidly deteriorates until the starting lower limit voltage reaches a predetermined value. When the Pb battery deteriorates and the starting lower limit voltage becomes a predetermined value or less, the mode is switched and the Pb mode is set. In the Pb mode, charge / discharge control is performed using the recommended capacity of the Pb battery as the capacity management target value. As a result, further rapid deterioration of the Pb battery can be prevented, and the life of the Pb battery is extended.

  According to said structure, the following effects are exhibited.

In the state where the battery 20 is not deteriorated, charge / discharge control is performed in a state where the capacity is small as compared with the deteriorated state, and in the state where the battery 20 is deteriorated, it is compared with the state where the battery 20 is not deteriorated. Thus, charge / discharge control is performed in a state where the capacity is large. For this reason, in a state where the AGM battery is mounted and the AGM battery is not deteriorated, the charging current at the time of regenerative power generation can be increased. Therefore, the performance of the AGM battery can be sufficiently exhibited, and improvement in fuel consumption can be expected. On the other hand, when a Pb battery is installed, it deteriorates early until it becomes a deteriorated state, but after it becomes deteriorated, it is charged / discharged in a state where the capacity is larger than the state where it has not deteriorated. Is controlled. Therefore, even if a Pb battery is mounted on vehicle 100 that is assumed to be mounted with an AGM battery, the life of the Pb battery can be extended.

-By controlling charging / discharging so that the capacity of the battery 20 becomes the capacity management target value, it is possible to prevent unnecessary charging and improve fuel efficiency.

In a state where the battery 20 is not deteriorated, charge / discharge control is started earlier than in a state where the battery 20 is deteriorated. Therefore, useless charging can be prevented and fuel consumption can be improved.

In the AGM mode, the idling stop control can be started at an early stage because the idling stop control is started when it is determined that the capacity of the battery 20 has reached the predetermined value. Therefore, the improvement effect of the fuel consumption by idling stop control can be expected.

<Modification>
In the above-described embodiment, the Pb battery is described as being mounted on the vehicle 100 on which the AGM battery is assumed to be mounted, but the vehicle 100 on which an EFB (Enhanced Flooded Battery) is assumed is mounted instead of the AGM battery. Applicable. In this case, when the vehicle 100 is shipped and when the battery 20 is replaced, the EFB mode in which charge / discharge control is performed so that the recommended capacity of the EFB is obtained may be set, and the Pb mode may be switched by the deterioration determination. Further, the present invention is not limited to the above-described batteries, and can be similarly applied to batteries having the same deterioration characteristics as Pb batteries, that is, batteries whose internal resistance increases with deterioration.

In the above embodiment, once the deterioration determination of the battery 20 is performed, the mode remains switched until the battery 20 is replaced. However, the deterioration determination is performed when the engine 1 is started and the deterioration determination is reset when the engine 1 is stopped. It is good also as what performs. In this case, when the engine 1 is stopped by the idling stop control or when the deterioration is determined even when the driver performs the idling stop operation, the capacity determination control is performed every time the idling stop is performed. It becomes. As a result, the period during which capacity maintenance and regeneration control are performed is shortened, which may lead to deterioration in fuel consumption. Therefore, for example, when the user does not use the vehicle 100 for a predetermined time, that is, when the engine 1 is stopped and the engine 1 is not restarted for the predetermined time, the deterioration determination may be reset. .

In the above embodiment, the deterioration determination of the battery 20 is performed by measuring the lower limit voltage when the engine 1 is started. However, the deterioration determination may be performed by measuring the internal resistance of the battery 20. Further, the deterioration determination may be performed by measuring the rotational speed of the crank by the starter motor 40 when the engine 1 is started.

In the above embodiment, the capacity for charge / discharge control and the capacity management target value are different from each other, but both may be the same value. That is, after the engine 1 is started, the applied voltage is set to the maximum value until the charging current reaches a current corresponding to the capacity management target value, and charge / discharge control is performed when the charging current reaches a current corresponding to the capacity management target value. It is good to start.

In the above embodiment, it is determined whether or not the battery 20 has deteriorated by measuring the starting lower limit voltage when the engine 1 is started, and the capacity of the battery 20 is determined by measuring the charging current of the battery 20. Thus, charge / discharge control is performed. However, the internal resistance and charging current of the battery 20 are affected by changes in temperature. Therefore, a thermometer may be provided, and when determining the deterioration of the battery 20, and when determining the capacity based on the charging current of the battery 20, correction by temperature may be performed.

In the above embodiment, the capacity maintenance control is performed in both the AGM mode and the Pb mode. However, in the Pb mode, constant voltage control may be performed in addition to the suppression control. When the capacity management target value is controlled by the capacity maintenance control, the charging current during regeneration increases as the capacity management target value decreases, and the battery 20 can be charged efficiently. However, in the case of the Pb mode, the capacity maintenance control is performed in a state where the capacity management target value is higher than that in the AGM mode. Therefore, the charging current during regeneration cannot be increased as much as in the AGM mode. Therefore, the fuel efficiency improvement effect obtained by performing the capacity maintenance control in the Pb mode is smaller than that in the AGM mode. Therefore, the constant voltage control may be performed without performing the capacity maintenance control in the Pb mode in which the fuel efficiency improvement effect by performing the capacity maintenance control is small.

  20 ... battery, 30 ... ECU, 50 ... ammeter, 60 ... voltmeter.

Claims (12)

Deterioration state determining means (60, 30) for determining that the battery has deteriorated when a parameter indicating a deterioration state of the battery (20) exceeds a predetermined value;
Capacity detecting means (50, 30) for detecting the capacity of the battery;
When it is determined by the deterioration state determination means that the battery has deteriorated, the capacity of the battery is increased so that the capacity increases compared to the case where the deterioration state determination means does not determine that the battery has deteriorated. A charge control device comprising capacity management means (30) for controlling charge / discharge. In accordance with the determination result of the deterioration state determination means, further comprising target value setting means (30) for setting a capacity management target value that is a target value of the capacity of the battery,
The charge control device according to claim 1, wherein the capacity management unit controls charging / discharging of the battery so that the capacity becomes the capacity management target value. As the battery, a first battery and a second battery can be used,
The first battery has a first recommended capacity defined as a capacity capable of suppressing deterioration, and the second battery has a second capacity less than the first recommended capacity as a capacity capable of suppressing deterioration. Recommended capacity is defined,
The target value setting means sets the capacity management target value based on the first recommended capacity when the deterioration state determination means determines that the battery has deteriorated, and the deterioration state determination means determines that the battery is The charge control device according to claim 2, wherein when it is not determined that the battery has deteriorated, the capacity management target value based on the second recommended capacity is set.   The charge control device according to claim 3, wherein the first battery is a Pb battery, and the second battery is an AGM battery. The capacity detection means detects the capacity by measuring a charging current of the battery,
A first current value that is the charging current based on the first recommended capacity is defined,
A second current value that is the charging current based on the second recommended capacity is defined,
When the deterioration state determining means determines that the battery has deteriorated, the charge / discharge control is started when the charging current reaches the first current value, and the battery is deteriorated by the deterioration state determining means. 5. The charging control device according to claim 3, wherein when it is not determined that the charging is performed, the charging and discharging control is started when the charging current reaches the second current value. 6.   The capacity management means, when the deterioration state determination means determines that the battery has deteriorated, compared to the case where the deterioration state determination means does not determine that the battery has deteriorated, the capacity management target The charge control device according to claim 2, wherein the value is set to a large value. The capacity detection means detects the capacity by measuring a charging current of the battery,
The capacity management unit starts the charge / discharge control when the charging current becomes equal to or less than a predetermined value determined according to whether or not the battery has deteriorated. The charge control device according to any one of 1, 2, and 6.   The charge control device according to claim 1, wherein the deterioration state determination unit determines whether or not the battery has deteriorated when the charge control device is activated. The charging control device is mounted on a vehicle including a starter motor (40),
The said deterioration state determination means determines whether the said battery deteriorated by measuring the lower limit voltage at the time of the start of the said starter motor, The any one of Claims 1-8 characterized by the above-mentioned. Charge control device. A vehicle (100) comprising the charge control device according to claim 5, an internal combustion engine (1), and an idling stop function for automatically stopping the internal combustion engine,
When the deterioration state determining means determines that the battery is deteriorated, the control of the idling stop function is started when the charging current becomes equal to or less than the first current value, and the deterioration state determining means If it is not determined that the battery has deteriorated, the vehicle starts control of the idling stop function when the charging current becomes equal to or less than the second current value. A vehicle comprising the charge control device according to claim 7, an internal combustion engine, and an idling stop function for automatically stopping the internal combustion engine,
A vehicle which starts control of the idling stop function when the charging current becomes equal to or less than a predetermined value which depends on whether or not the battery has deteriorated. A battery charge control method executed by a charge control device,
A determination step for determining that the battery has deteriorated when a parameter indicating a deterioration state of the battery exceeds a predetermined value;
A detecting step for detecting a capacity of the battery;
When it is determined in the determination step that the battery has deteriorated, the charge / discharge of the battery is controlled so that the capacity increases compared to the case where it is not determined in the determination step that the battery has deteriorated. A charge control method comprising control steps.

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