JP6355942B2 - Charge control device and charge control method - Google Patents

Description

  The present invention relates to a charge control device and a charge control method.

  In recent years, in order to improve the fuel efficiency of a vehicle, a technique for converting kinetic energy of the vehicle into electric energy by an alternator during deceleration and storing it in a secondary battery is becoming widespread.

  In Patent Document 1, the field current of the alternator is controlled based on the difference between the adjustment voltage and the voltage of the secondary battery so as to converge to the adjustment voltage, and the adjustment voltage during deceleration from the secondary battery voltage during the low-speed acceleration period. A technique is disclosed in which a high adjustment voltage is set lower than a secondary battery voltage during a low-speed deceleration period.

  Further, Patent Document 2 calculates a charging target current value based on the difference between the target voltage and the secondary battery voltage, performs charging control based on the target current value, and based on the alternator braking / driving force. There is disclosed a technique for calculating a target current value of an alternator, performing braking / driving force control of the alternator based on the target current value, and correcting an SOC value.

JP 2001-245441 A JP 2009-165230 A

  By the way, in the technologies disclosed in Patent Documents 1 and 2, when the generated voltage of the alternator deviates from the target value, the balance of charge and discharge cannot be balanced, so that the SOC fluctuates, and as a result, at the time of deceleration In addition to this, there is a problem in that supplementary charging using fuel is performed in a supplementary manner, so that fuel efficiency is deteriorated and the secondary battery is taken out to the load. In addition, since the regenerative current at the time of deceleration is not sufficiently stored, there is a problem that the above-described supplementary charging is executed and fuel consumption is deteriorated or the life of the secondary battery is shortened.

  An object of the present invention is to provide a charge control device and a charge control method capable of efficiently charging a secondary battery with a regenerative current and extending the life of the secondary battery.

In order to solve the above-described problems, the present invention provides a charge control device for controlling a state of a secondary battery mounted on a vehicle based on a target value of SOC of the secondary battery, wherein the open circuit of the secondary battery is Estimating means for estimating voltage, measuring means for measuring the power generation voltage during regeneration of the alternator for charging the secondary battery, setting means for setting a target voltage difference from the target charging current, and power generation during the regeneration Adjust at least one of the generated voltage at the time of regeneration of the alternator and the target value of the SOC of the secondary battery so that the difference value between the voltage and the open circuit voltage becomes the target voltage difference set by the setting means Adjusting means.
According to such a configuration, the secondary battery can be efficiently charged by the regenerative current and the life of the secondary battery can be extended.

Further, according to the present invention, when the difference value is smaller than the target voltage difference, the adjusting means increases the power generation voltage during regeneration of the alternator, and the difference value is larger than the target voltage difference. Is characterized in that the generated voltage during regeneration of the alternator is reduced.
According to such a configuration, a constant charging current can be obtained by adjusting the power generation voltage of the alternator.

Further, according to the present invention, when the difference value is smaller than the target voltage difference, the adjustment unit decreases the SOC target value of the secondary battery, and the difference value is larger than the target voltage difference. In this case, the SOC target value of the secondary battery is increased.
According to such a configuration, a constant charging current can be obtained by adjusting the SOC target value.

Further, according to the present invention, when the difference value is smaller than the target voltage difference, and the power generation voltage at the time of regeneration of the alternator reaches an upper limit, the adjusting means is configured to set a target SOC of the secondary battery. It is characterized by decreasing the value.
According to such a configuration, when the power generation voltage of the alternator reaches the upper limit, a constant charging current can be obtained by reducing the target value of the SOC.

Moreover, the present invention is characterized in that the adjusting means reduces the generated voltage during regeneration of the alternator when the open circuit voltage of the secondary battery reaches an upper limit.
According to such a configuration, when the open circuit voltage of the secondary battery reaches the upper limit, a constant charging current can be obtained by increasing the power generation voltage during regeneration.

The present invention is further characterized by further comprising a calculation means for calculating the internal resistance of the secondary battery.
According to such a structure, charge control according to the change of the internal resistance of the secondary battery can be performed.

Moreover, the present invention is characterized in that the setting means sets the target voltage difference from the target charging current and the internal resistance.
According to such a configuration, a constant charging current can be obtained even when the internal resistance of the secondary battery changes.

Further, the present invention is characterized in that the adjusting means adjusts at least one of a power generation voltage during regeneration of the alternator and a target value of SOC of the secondary battery according to a change in the internal resistance.
According to such a configuration, it is possible to obtain a constant charging current even when there is a change in temperature, for example, by taking into account a change in internal resistance.

Moreover, the present invention is characterized in that the adjusting means changes the target charging current according to a deterioration state of the secondary battery.
According to such a configuration, by changing the SOC target value according to the deterioration state of the secondary battery, a constant charging current can be obtained regardless of the deterioration of the secondary battery.

Further, according to the present invention, when there is a divergence between the indicated value of the generated voltage of the alternator and the voltage value of the actually output voltage, the adjusting means executes a process of calibrating the difference. It is characterized by that.
According to such a configuration, the accuracy of control can be improved by obtaining an accurate generated voltage corresponding to the indicated value from the alternator.

Further, according to the present invention, when the secondary battery has deteriorated more than a predetermined value, the adjusting unit controls the target charging current to be smaller than a predetermined value. It shifts to the control which maintains remaining capacity, It is characterized by the above-mentioned.
According to such a configuration, further deterioration of the secondary battery can be prevented.

In addition, the present invention is characterized by having a presenting means for presenting information prompting the user to replace the secondary battery when a predetermined period elapses after shifting to the control for maintaining the remaining capacity.
According to such a configuration, the replacement time of the secondary battery can be presented to the user.

Further, according to the present invention, when the adjustment means reaches the target SOC, the power generation voltage of the alternator is adjusted to be high when the vehicle is decelerated, and the secondary battery is charged with the electric power obtained by regeneration. In addition, power is supplied from the secondary battery to the load by adjusting the power generation voltage of the alternator to be low.
According to such a configuration, fuel consumption can be improved by reducing the opportunity to consume the fuel and charge the secondary battery.

Further, the present invention is characterized in that the alternator is an analog type alternator capable of setting a high / low power generation voltage, or a digital type alternator capable of outputting a power generation voltage based on an indicated value.
According to such a configuration, the secondary battery can be efficiently charged using the analog type or digital type alternator.

Further, in the present invention, when the alternator is an analog type alternator capable of setting the high / low of the generated voltage, the adjusting means sets the generated voltage to a high state when charging the voltage of the secondary battery. When adjusting and discharging the secondary battery, the power generation voltage is adjusted to a low state.
According to such a configuration, the secondary battery can be efficiently charged using the analog type alternator.

Further, the present invention is characterized in that the charge control device is configured as a single unit, incorporated in a relay box or a junction box, or incorporated in a secondary battery state detection device.
According to such a configuration, the charging control device can be arranged corresponding to various environments.

Further, the present invention provides a charge control method by a charge control device that controls a state of a secondary battery mounted on a vehicle, wherein the charge control device sets a target charge current to the secondary battery during regenerative power generation. A step of obtaining an open circuit voltage of the secondary battery, a measuring step of measuring a generated voltage during regeneration of an alternator that charges the secondary battery, and a target voltage difference from the target charging current. A setting step for setting, a power generation voltage during regeneration, and a power generation voltage during regeneration of the alternator and the secondary voltage so that a difference value between the power generation voltage during regeneration and the open circuit voltage becomes the target voltage difference set in the setting step. An adjustment step of adjusting at least one of the target values of the SOC of the battery.
According to such a method, the secondary battery can be efficiently charged by the regenerative current and the life of the secondary battery can be extended.

  According to the present invention, it is possible to provide a charge control device and a charge control method capable of efficiently charging a secondary battery with a regenerative current and extending the life of the secondary battery.

It is a figure which shows the structural example of the charge control apparatus which concerns on embodiment of this invention. It is a block diagram which shows the detailed structural example of the control part of FIG. It is a figure for demonstrating operation | movement of embodiment of this invention. It is a figure for demonstrating operation | movement of embodiment of this invention. It is a figure for demonstrating operation | movement of embodiment of this invention. It is a figure for demonstrating operation | movement of embodiment of this invention. It is a figure which shows the relationship between OCV and SOC of a secondary battery. It is a figure which shows the deterioration of a secondary battery, and the change of SOC required for various operation | movement. It is a flowchart for demonstrating an example of the process performed in embodiment of this invention. It is a flowchart for demonstrating the detail of the process of FIG.9 S21.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of Embodiment FIG. 1 is a diagram illustrating a power supply system of a vehicle having a charge control device according to an embodiment of the present invention. In this figure, the charging control device 1 includes a control unit 10, a voltage sensor 11, a current sensor 12, a temperature sensor 13, and a discharge circuit 15 as main components, and detects the state of the secondary battery 14. Here, the control unit 10 refers to outputs from the voltage sensor 11, the current sensor 12, and the temperature sensor 13 to detect the state of the secondary battery 14. The voltage sensor 11 detects the terminal voltage of the secondary battery 14 and notifies the control unit 10 of it. The current sensor 12 detects the current flowing through the secondary battery 14 and notifies the control unit 10 of the current. The temperature sensor 13 detects the secondary battery 14 itself or the surrounding environmental temperature, and notifies the control unit 10 of it.

  The secondary battery 14 is composed of, for example, a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery, and is charged by the alternator 16 to drive the starter motor 18 to start the engine and load 19 To supply power. The alternator 16 is driven by the engine 17 to generate AC power, convert it into DC power by a rectifier circuit, and charge the secondary battery 14.

  The engine 17 is composed of, for example, a reciprocating engine such as a gasoline engine and a diesel engine, a rotary engine, or the like. The engine 17 is started by a starter motor 18 and drives driving wheels via a transmission to give propulsive force to the vehicle. Drive to generate power. The starter motor 18 is constituted by, for example, a DC motor, generates a rotational force by the electric power supplied from the secondary battery 14, and starts the engine 17. The load 19 is configured by, for example, an electric steering motor, a defogger, an ignition coil, a car audio, a car navigation, and the like, and operates with electric power from the secondary battery 14.

  FIG. 2 is a diagram illustrating a detailed configuration example of the control unit 10 illustrated in FIG. 1. As shown in this figure, the control unit 10 includes a CPU (Central Processing Unit) 10a, a ROM (Read Only Memory) 10b, a RAM (Random Access Memory) 10c, a communication unit 10d, and an I / F (Interface) 10e. ing. Here, the CPU 10a controls each unit based on the program 10ba stored in the ROM 10b. The ROM 10b is configured by a semiconductor memory or the like, and stores a program 10ba or the like. The RAM 10c is configured by a semiconductor memory or the like, and stores data generated when the program ba is executed, and a parameter 10ca such as a table or a mathematical expression described later. The communication unit 10d communicates with an upper device such as an ECU (Electronic Control Unit) and notifies the host device of information. The I / F 10e converts the signals supplied from the voltage sensor 11, the current sensor 12, and the temperature sensor 13 into digital signals and takes them in.

(B) Description of Operation Principle of Embodiment Next, the operation principle of the embodiment will be described with reference to the drawings. 3-8 is a figure for demonstrating the operation | movement of embodiment of this invention. First, FIG. 3 is a diagram for explaining an example of temporal changes in the open circuit voltage of the secondary battery 14 and the generated voltage of the alternator 16 when deterioration due to the decrease in the electrolyte is dominant. Depending on the type of deterioration, the behavior differs from that shown in FIG. In FIG. 3, the horizontal axis indicates time, and the vertical axis indicates voltage. In this embodiment, in order to obtain a predetermined target charging current, the target SOC is constant, and the generated voltage during regeneration of the alternator is adjusted. The lower solid line in FIG. 3 shows an example of the temporal change of the open circuit voltage (OCV) of the secondary battery 14, and the broken line on the upper broken line shows the temporal generation voltage during regeneration of the alternator 16. An example of the change is shown. As shown in this figure, in the present embodiment, in the range of “regeneration power amount maintenance”, the power generation voltage at the time of regeneration of the alternator 16 and the secondary battery are obtained so that a charging current emphasizing the efficiency of regenerative charging can be obtained. ΔV which is a difference value from the open circuit voltage of 14 is controlled. As a result, during regeneration such as when the vehicle decelerates, a constant current (generally a current corresponding to a value obtained by dividing ΔV by the internal resistance R) from the alternator 16 to the secondary battery 14 is obtained. Therefore, the secondary battery 14 can be reliably charged by the regenerative current regardless of the state of the secondary battery 14 or the like.

  FIG. 7 is a diagram showing the relationship between OCV and SOC when the secondary battery 14 is new (solid line) and deteriorated (broken line). Regardless of whether the secondary battery 14 is deteriorated or not, there is a correlation between the OCV and the SOC. As the deterioration progresses, the inclination of the graph increases and the position moves to the right side of the figure. Therefore, for example, when the SOC is “a”, the OCV is “a ′” at the time of a new product, but “b ′” (b ′> a ′) at the time of deterioration. In this embodiment, since adjustment is performed by the generated voltage at the time of regeneration of the alternator 16, in order to ensure the acceptability of the regenerative current to the secondary battery 14, the generated voltage is changed to b′−a ′ according to deterioration. Only increase processing.

  Further, in the present embodiment, when the secondary battery 14 further deteriorates, it enters the range of “remaining remaining capacity” shown in FIG. 3 and reduces the target charging current. Therefore, ΔV is reduced according to the deterioration of the secondary battery 14. As a result, the amount of power accepted during regeneration is reduced, but the burden on the secondary battery 14 can be reduced and the life of the secondary battery 14 can be extended.

  In the present embodiment, ΔV is controlled in consideration of a voltage drop due to the change ΔR of the resistance R of the secondary battery 14. More specifically, in the secondary battery 14, the internal resistance R changes according to, for example, temperature, polarization, and stratification (see the hatched portion surrounding the lower solid line in FIG. 3). For example, when the internal resistance R increases, the open circuit voltage that does not depend on the current does not change, but a voltage drop corresponding to the current occurs. Therefore, when the internal resistance R increases by ΔR, the difference value ΔV is increased by an amount corresponding to a value I × ΔR obtained by multiplying the current I flowing by this ΔR. Thereby, even when the internal resistance changes due to environmental changes or the like, a certain amount of regenerative charging can be performed.

  In the present embodiment, control can be performed in consideration of individual differences of the alternator 16. More specifically, the alternator 16 is configured to output a voltage corresponding to the indicated value of the voltage, but depending on the alternator 16, there may be a difference between the indicated value and the output voltage ( (See hatched area surrounding the upper broken line in FIG. 3). In such a case, charging by regeneration cannot be performed properly, and such an error can be eliminated by calibrating the indicated value based on the actually output voltage value. For example, when the instruction value to the alternator 16 is 14.5V and the actually output voltage is 14.3V, the instruction value can be set to 14.7V.

  In addition, as control of (DELTA) V, the target value (target SOC) of SOC of the secondary battery 14 can also be controlled. An example of the temporal change of the open circuit voltage of the secondary battery 14 and the generated voltage of the alternator 16 in this case is shown in FIG. In the range of “maintaining regenerative electric energy”, the open circuit voltage of the secondary battery 14 is kept constant by controlling the target SOC. This process corresponds to an operation (arrow A) for changing the target SOC from a to b in FIG. Next, when entering the “remaining capacity maintenance” range, a process of increasing the target SOC is performed in order to decrease ΔV. Since the relationship between the OCV and the SOC at the time of deterioration is a broken line in FIG. 7, the process for increasing the target SOC is a process in the direction of arrow B in FIG. Thereby, for example, deterioration due to sulfation can be suppressed.

  In order to determine whether the range is “maintenance of regenerative energy” or “maintenance of remaining capacity”, for example, (1) SOH (State of Health) of the secondary battery 14 is a predetermined value. When the value reaches the value, it is determined that the range is “maintenance of remaining capacity” or (2) “remaining capacity” is maintained when the open circuit voltage of the secondary battery 14 before starting the engine 17 reaches a predetermined value. (3) As shown in FIG. 8, when the target SOC is c, it is determined that the range is “maintain remaining capacity”, or (4) the charging current of the secondary battery 14 When the charging voltage reaches a predetermined value, it can be determined that the “remaining capacity is maintained” range.

  FIG. 8 shows the time required for deterioration of the target SOC (solid line) that can maintain a predetermined charging current and the minimum charging rate (dotted line) necessary for starting the engine 17 when the deterioration behavior as shown in FIG. 7 is shown. FIG. The target SOC that can maintain the predetermined charging current indicated by the solid line decreases with time, while the minimum charging rate required to start the engine 17 indicated by the broken line increases with time. These intersect at time T1. Therefore, up to time T1, importance is placed on the efficiency of regenerative charging, and control is performed by “maintaining the amount of regenerative power”. It can be carried out. The value of T1 is generally about 2 to 3 years. Of course, there are other cases.

  In the above embodiment, an example has been shown in which one of the generated voltage and the target SOC at the time of regeneration of the alternator 16 is made constant and the other is adjusted. However, the adjustment target is changed as time passes or both are adjusted simultaneously. It is also possible to do. For example, in FIG. 5, the target SOC is kept constant until time T2, and ΔV is adjusted to be constant by adjusting the power generation voltage during regeneration of the alternator. However, since the power generation upper limit voltage Vamax that is the upper limit of the power generation voltage during regeneration of the alternator is reached at time T2, the subsequent control is switched to the adjustment of the target SOC. In FIG. 6, ΔV is adjusted by adjusting the target SOC while keeping the power generation voltage during regeneration of the alternator constant until time T3. However, since the open circuit voltage at the target SOC has reached the open circuit upper limit voltage Vomax at time T3, the subsequent control is switched to the adjustment of the power generation voltage during regeneration of the alternator.

(C) Description of Detailed Operation of Embodiment Next, the operation of the embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a flowchart for explaining an example of a process for adjusting the generated voltage during regeneration of the alternator 16 while keeping the target SOC constant in the initial state. When the processing of this flowchart is started, the following steps are executed.

  In step S <b> 10, the CPU 10 a of the control unit 10 sets an initial value of the target charging current Itar of the secondary battery 14. The initial value is set so that regenerative charging is performed efficiently.

  In step S <b> 11, the CPU 10 a of the control unit 10 acquires the open circuit voltage Vo of the secondary battery 14. More specifically, the CPU 10a can obtain the open circuit voltage Vo by referring to the output of the voltage sensor 11 when a predetermined time (for example, ten hours) has elapsed since the engine 17 was stopped.

  In step S <b> 12, the CPU 10 a executes a calibration process for the alternator 16. More specifically, the CPU 10a can control the output voltage of the alternator 16 by supplying an instruction value of the output voltage to the alternator 16, but there is no difference between the instruction value and the actually output voltage. Since the divergence may occur, the CPU 10a calculates the difference between the instruction value and the actual output value, and calibrates the alternator 16 by changing the instruction value so that this difference is eliminated.

  In step S13, the CPU 10a acquires the regenerative power generation voltage Va of the alternator 16 after being calibrated in step S12.

  In step S14, the CPU 10a acquires the value of the internal resistance R of the secondary battery 14.

  In step S15, the CPU 10a estimates the deterioration state of the secondary battery 14. In addition, as a deterioration condition, the deterioration condition of the secondary battery 14 can be estimated based on SOH (State of Health), for example.

  In step S16, the CPU 10a determines whether or not the secondary battery 14 belongs to the regenerative power maintenance range shown in FIG. 3 or the like based on the deterioration state of the secondary battery 14 estimated in step S15, and the regenerative power maintenance range. If it is determined that it belongs to (step S16: Yes), the process proceeds to step S18, and otherwise (step S16: No), the process proceeds to step S17.

  In step S17, the CPU 10a executes a process of changing the target charging current Itar to the remaining capacity maintaining process mode. Thereby, as shown in FIG. 3, it can transfer to a remaining capacity maintenance process.

  In step S18, the CPU 10a sets a target voltage difference Th (= Itar × R) from the target charging current Itar and the internal resistance R acquired in step S14.

  In steps S19 to S22, a process of adjusting the difference value (ΔV = Va−Vo) between the regenerative power generation voltage Va and the open circuit voltage Vo of the secondary battery based on the target voltage difference Th is performed. When the difference value ΔV does not coincide with the target voltage difference Th (step S19: No), in step S20, it is determined whether or not the difference value ΔV is less than the target voltage difference Th (ΔV <Th). If ΔV <Th (step S20: Yes), the process proceeds to step S21, and otherwise (step S20: No), the process proceeds to step S22. As an example of the value of the target voltage difference Th, “3V” can be used. Of course, other values may be used. When the secondary battery 14 enters the range of “remaining remaining capacity”, the target voltage difference Th is changed by changing the target charging current Itar in step S17. As shown in FIG. Th can be set to decrease.

  In step S <b> 21, the CPU 10 a executes a “power generation voltage increase process” that is a process of increasing the power generation voltage during regeneration of the alternator 16. Details of this processing will be described later with reference to FIG.

  In step S22, the CPU 10a decreases the generated voltage by decreasing the generated voltage value instructed to the alternator 16 at the time of regeneration.

  Through the processes in steps S19 to S22, when ΔV is smaller than the target voltage difference Th, the generated voltage increase process is executed, and when ΔV is larger than the target voltage difference Th, the generated voltage decrease process is executed. Is done. Thus, control is performed so that ΔV is equal to Th.

  In step S23, the CPU 10a determines whether or not to end the process, and when it is determined that the process is to be continued (step S23: No), the process returns to step S19 to repeat the generated voltage adjustment process. In step S23: Yes, the process ends.

  According to the above process, the generated voltage can be controlled so that the charging current during regenerative power generation becomes a predetermined target value.

  Next, with reference to FIG. 10, the details of the “power generation voltage increasing process” shown in step S21 of FIG. 9 will be described. When the flowchart of FIG. 10 is started, the following steps are executed.

  In step S30, the CPU 10a compares the regenerative power generation voltage Va acquired in step S13 of FIG. 9 with the power generation upper limit voltage Vamax, determines whether Va ≧ Vamax is satisfied, and when Va ≧ Vamax is satisfied. In step S30: Yes, the process proceeds to step S32. In other cases (step S30: No), the process proceeds to step S31. The power generation upper limit voltage Vamax is the maximum voltage that can be generated by the alternator 16, and can be set to, for example, 16V. Of course, depending on the type of the alternator 16, there may be other values.

  In step S31, the CPU 10a increases the generated voltage during regeneration of the alternator 16. More specifically, the instruction voltage to the alternator 16 is increased. Since the alternator 16 has been calibrated in step S12 of FIG. 9, the alternator 16 outputs an accurate voltage corresponding to the instruction voltage.

  In step S32, the CPU 10a compares the open circuit voltage Vo of the secondary battery 14 acquired in step S11 of FIG. 9 with the open circuit upper limit voltage Vomax to determine whether or not Vo ≧ Vomax is established. If it is determined that ≧ Vomax is established (step S32: Yes), the process ends and the process returns (returns) to the original process. Otherwise (step S32: No), the process proceeds to step S33. The open circuit upper limit voltage Vomax is an upper limit value of the open circuit voltage, and can be set to 13 V, for example. Of course, other values may be used depending on the type of the secondary battery 14.

  In step S33, the CPU 10a decreases the target SOC. Accordingly, when the generated voltage reaches the upper limit value, ΔV can be controlled by decreasing the target SOC.

  According to the above processing, when the regenerative power generation voltage Va is less than the power generation upper limit voltage Vamax, the regenerative power generation voltage is increased, and when the regenerative power generation voltage Va is equal to or higher than the power generation upper limit voltage Vamax, the open circuit voltage Since control for decreasing the target SOC is executed when Vo is lower than the open circuit upper limit voltage Vomax, ΔV can be controlled.

(D) Description of Modified Embodiment The above embodiment is an example, and it is needless to say that the present invention is not limited to the case described above. For example, in the above embodiment, the temperature is not described in detail to simplify the description, but for example, various parameters measured or estimated according to the temperature of the secondary battery 14 itself or the ambient temperature. (For example, the internal resistance R or the like) may be corrected.

  Further, in the above embodiment, the deterioration of the secondary battery 14 has been described by taking, as an example, the deterioration in which the OCV increases with respect to the same SOC, as shown in FIG. Such deterioration is mainly caused by a decrease in the electrolytic solution. In addition to this, the deterioration of the secondary battery 14 is caused by sulfation (lead sulfate). In deterioration due to sulfation, it is known that OCV decreases with respect to the same SOC (in FIG. 7, the straight line at the time of deterioration moves to the left with respect to the straight line at the time of a new article). Therefore, for such deterioration, for example, the target SOC may be temporarily increased in order to reduce sulfation. Of course, it is also assumed that either deterioration due to sulfation or deterioration due to decrease in electrolyte progresses, or both progress simultaneously, but in such a case, for the same SOC It may be determined which deterioration is dominant depending on whether the OCV decreases or increases, and the target SOC may be set based on the determination result.

  Further, in step S20 of the flowchart shown in FIG. 10, when the difference value ΔV is equal to or larger than the target voltage difference Th, the process proceeds to step S22, the power generation voltage of the alternator 16 is decreased, and the difference value ΔV is less than the target voltage difference Th. In this case, the process proceeds to step S21 and the power generation voltage of the alternator 16 is increased. However, when the difference value ΔV is equal to or larger than the target voltage difference Th, the target value of the SOC of the secondary battery 14 is increased. When the difference value ΔV is less than the target voltage difference Th, the SOC target value may be decreased.

  In addition, after the transition to the control for maintaining the remaining capacity shown in FIG. 3, when a predetermined time has elapsed, information for prompting replacement of the secondary battery 14 may be presented to the user. For example, a message prompting the replacement of the secondary battery 14 is displayed on the display unit provided on the dashboard of the driver's seat via the communication unit 10d, a warning light is turned on, or a voice warning is given. You may do.

  In addition, when the target SOC is reached, the power generation voltage of the alternator 16 is adjusted to be high when the vehicle is decelerated, so that the secondary battery 14 is charged with regenerative power. Electric power may be supplied from the secondary battery 14 to the load 19 by adjusting the generated voltage low. According to such a method, fuel consumption can be improved by reducing the opportunity to drive the alternator 16 by consuming fuel by the engine 17.

  Further, as an example of the alternator 16, a case where a digital alternator that outputs a voltage corresponding to the indicated value of the generated voltage is used has been described as an example. For example, high / low of the generated voltage can be specified. An analog type alternator may be used. For example, when charging the secondary battery 14, when “high” is instructed, a voltage of 14.5 V or more is output, and when discharging the secondary battery 14, “low” is instructed. A voltage of around 12.5V can be output.

  Further, the charging control device 1 according to the present invention may be configured as a single unit, or may be built in a relay box or a junction box. Or you may make it incorporate in the same housing | casing as a secondary battery state detection apparatus.

DESCRIPTION OF SYMBOLS 1 Charge control apparatus 10 Control part 10a CPU (estimation means, measurement means, adjustment means)
10b ROM
10c RAM
10d Communication unit 10e I / F
DESCRIPTION OF SYMBOLS 11 Voltage sensor 12 Current sensor 13 Temperature sensor 14 Secondary battery 15 Discharge circuit 16 Alternator 17 Engine 18 Starter motor 19 Load

Claims (17)

In the charge control device for controlling the state of the secondary battery mounted on the vehicle based on the target value of the SOC of the secondary battery,
Estimating means for estimating and obtaining an open circuit voltage of the secondary battery;
Measuring means for measuring the generated voltage during regeneration of the alternator for charging the secondary battery;
Setting means for setting the target voltage difference from the target charging current;
The power generation voltage during regeneration of the alternator and the target value of the SOC of the secondary battery so that the difference value between the power generation voltage during regeneration and the open circuit voltage becomes the target voltage difference set by the setting means. Adjusting means for adjusting at least one of
A charge control device comprising:   The adjusting means increases the generated voltage during regeneration of the alternator when the difference value is smaller than the target voltage difference, and adjusts the alternator when the difference value is larger than the target voltage difference. The charge control device according to claim 1, wherein the power generation voltage during regeneration is reduced.   The adjusting means decreases the SOC target value of the secondary battery when the difference value is smaller than the target voltage difference, and when the difference value is larger than the target voltage difference, The charge control device according to claim 1, wherein the target value of the SOC of the secondary battery is increased.   In the case where the difference value is smaller than the target voltage difference and the generated voltage at the time of regeneration of the alternator reaches an upper limit, the adjusting means decreases the SOC target value of the secondary battery. The charge control device according to claim 1, wherein the charge control device is a charge control device. The said adjustment means reduces the electric power generation voltage at the time of the regeneration of the said alternator, when the said open circuit voltage of the said secondary battery reaches an upper limit. The charging control device described.   The charging control apparatus according to claim 1, further comprising a calculating unit that calculates an internal resistance of the secondary battery.   The charging control apparatus according to claim 6, wherein the setting unit sets the target voltage difference from the target charging current and the internal resistance.   The said adjustment means adjusts at least one of the electric power generation voltage at the time of the regeneration of the said alternator, and the target value of SOC of the said secondary battery according to the change of the said internal resistance, The Claim 6 or 7 characterized by the above-mentioned. Charge control device.   9. The charging control device according to claim 1, wherein the adjustment unit changes the target charging current according to a deterioration state of the secondary battery.   The adjusting means, when there is a divergence between the indicated value of the generated voltage of the alternator and the voltage value of the actually output voltage, executes a process of calibrating the difference. Item 10. The charge control device according to any one of Items 1 to 9.   The adjustment means controls the remaining capacity of the secondary battery by controlling the target charging current to be smaller than a predetermined value when the secondary battery has deteriorated more than a predetermined value. The charge control device according to claim 1, wherein the charge control device is transferred to the charge control device.   The charging control according to claim 11, further comprising a presentation unit that presents information prompting the user to replace the secondary battery when a predetermined period has elapsed after the shift to the control for maintaining the remaining capacity. apparatus.   When the target SOC is reached, the adjusting means adjusts the power generation voltage of the alternator to a high level when the vehicle decelerates and charges the secondary battery with the electric power obtained by regeneration. The charge control device according to any one of claims 1 to 12, wherein electric power is supplied from the secondary battery to a load by adjusting a generated voltage to be low.   14. The alternator is an analog type alternator capable of setting a high / low power generation voltage, or a digital type alternator capable of outputting a power generation voltage based on an indicated value. The charging control device according to claim 1.   When the alternator is an analog alternator capable of setting the high / low of the generated voltage, the adjusting means adjusts the generated voltage to a high state when charging the voltage of the secondary battery, and the secondary The charging control device according to claim 14, wherein when the battery is discharged, the generated voltage is adjusted to a low state.   The charge control device is configured as a single unit, is built in a relay box or a junction box, or is built in a secondary battery state detection device. The charge control device according to item 1. In the charge control method by the charge control device that controls the state of the secondary battery mounted on the vehicle,
The charge control device is
A current setting step for setting a target charging current to the secondary battery during regenerative power generation;
A obtaining step for obtaining an open circuit voltage of the secondary battery;
A measurement step of measuring a generated voltage during regeneration of the alternator for charging the secondary battery;
A setting step for setting a target voltage difference from the target charging current;
The power generation voltage at the time of regeneration of the alternator and the target value of the SOC of the secondary battery so that the difference value between the power generation voltage at the time of regeneration and the open circuit voltage becomes the target voltage difference set in the setting step. An adjustment step for adjusting at least one of
The charge control method characterized by having.

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