JP2011010418A - Auxiliary charging device and auxiliary charging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply power to a battery efficiently and stably while controlling power supply from the capacitor to the battery based on the voltage of the capacitor while avoiding significant deterioration of the performance of the capacitor. .
SOLUTION: The auxiliary charging device 100 of the present invention boosts the electric power stored in the capacitor 120, the solar battery 110 that converts light energy into electric power, the capacitor 120 that stores electric power converted by the solar battery 110, and the like. When the voltage supplied from the capacitor to the battery 102 is lower than the trickle charge current of the battery, the capacitor voltage measuring unit 122 that measures the voltage of the capacitor, and the voltage of the capacitor 120 is equal to or higher than the first predetermined value The power control unit 152 turns on the output of the booster circuit so that the power stored in the capacitor is supplied to the battery.
[Selection] Figure 1

Description

  The present invention relates to an auxiliary charging device and an auxiliary charging method for supplying electric power generated by a solar cell to a battery.

  A solar cell is a device that converts light energy such as sunlight and lighting into electric power. Sunlight used in solar cells can be used permanently because it does not run out. In addition, since the solar cell directly converts light energy into electric power, it does not involve noise and emissions, and is excellent in terms of environment. As described above, the solar cell is excellent in terms of the environment and does not require maintenance, and once it is mounted on the device, power can be obtained permanently. Therefore, the solar cell is attracting attention as a new power supply means.

  However, since the generated voltage per cell is generally low and the generated voltage changes significantly according to the amount of light irradiated, the solar cell uses the power converted by the solar cell as it is to provide stable power to the load. It is difficult to supply.

  Therefore, the power converted by the solar cell is boosted by a booster circuit, temporarily stored in a battery (secondary battery), and the power is supplied from the battery to the load. There is also a technology in which a large-capacity capacitor is disposed between the solar cell and the booster circuit, and the electric power converted by the solar cell is stored in the battery through the capacitor. In such a technique, in order to prevent the battery from being overcharged, power supply from the capacitor to the battery is stopped when the battery is fully charged.

  However, since the electric power converted by the solar cell is always supplied to the capacitor, the electric power converted by the solar cell is continuously supplied to the capacitor when the battery is fully charged. As a result, the voltage of the capacitor exceeds the allowable range, and the performance of the capacitor may be significantly deteriorated.

  Therefore, a technique for preventing deterioration of the capacitor by disposing a current limiting circuit between the capacitor and the battery and limiting the voltage of the capacitor is disclosed (for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-210776

  In recent years, capacitors having a larger capacitance have been developed. However, there are cases where the power storage function is significantly deteriorated when the voltage falls below a predetermined voltage. However, in the conventional technique described above, when the battery is fully charged, power is stopped from the capacitor. However, when the battery is not fully charged, power is always supplied from the capacitor to the battery.

  Therefore, even if a capacitor having a voltage operating lower limit value is used in the conventional technology, the minimum voltage necessary for the capacitor to maintain the power storage function cannot be secured, and the performance of the capacitor is finally greatly improved. Will deteriorate.

  In addition, when such an auxiliary charging device using solar cells is applied to a vehicle, the fluctuation range of the battery voltage varies significantly depending on the usage state of the vehicle, for example, whether or not the ignition key is on. Variations in the amount of power supplied from the capacitor to the battery are also significantly different. Therefore, if the voltage measurement frequency of the capacitor for the purpose of protecting the capacitor is kept high, the arithmetic processing becomes complicated until the ignition key is turned off, and the processing load increases. Conversely, if the voltage measurement frequency is kept low, the ignition key is turned on and battery power is consumed significantly. When the capacitor is suddenly depressurized, the depressurization cannot be detected, and the performance of the capacitor is significantly degraded. I had to do it.

  Therefore, in view of such problems, the present invention controls the power supply from the capacitor to the battery based on the voltage of the capacitor, thereby avoiding significant deterioration of the performance of the capacitor and efficiently and stably in the battery. An object is to provide an auxiliary charging device and an auxiliary charging method capable of supplying electric power.

  In order to solve the above problems, an auxiliary charging device of the present invention is an auxiliary charging device that charges a battery, a solar cell that converts light energy into electric power, and a capacitor that stores electric power converted by the solar cell, Boosting the power stored in the capacitor and limiting the current supplied from the capacitor to the battery to be less than the trickle charge current of the battery, the capacitor voltage measuring unit for measuring the voltage of the capacitor, and the voltage of the capacitor And a power control unit that turns on the output of the booster circuit so that the power stored in the capacitor is supplied to the battery when the value is equal to or greater than a predetermined value.

  When the voltage of the capacitor is equal to or higher than the first predetermined value, the current supplied from the capacitor to the battery is set to a current equal to or lower than the trickle charge current, so that the auxiliary charging device of the present invention can That is, even if the battery is fully charged, deterioration of the battery due to overcharging can be suppressed.

  The power control unit may electrically disconnect the booster circuit from the capacitor when the voltage of the capacitor is less than the first predetermined value.

  In the present invention, when the voltage of the capacitor is less than the first predetermined value, the power control unit electrically disconnects the booster circuit from the capacitor, so that the auxiliary charging device is below the minimum voltage required for the storage function of the capacitor. The power supply from the capacitor to the battery can be stopped before. Therefore, regardless of the voltage of the battery or the conversion efficiency of the solar cell, the capacitor can surely maintain the minimum voltage required for characteristics.

  The auxiliary charging device further includes a battery voltage measuring unit that measures the voltage of the battery, and when the voltage of the capacitor is equal to or higher than the first predetermined value and equal to or lower than a second predetermined value that is a value equal to or higher than the first predetermined value, The control unit may turn on / off the output of the booster circuit based on the voltage of the battery.

  When the voltage of the capacitor is within an allowable range, the power control unit is configured to turn on and off the output of the booster circuit so that power is supplied from the capacitor to the battery based on the voltage of the battery. This makes it possible to supply power from the capacitor to the battery appropriately and efficiently while reliably avoiding deterioration of the battery due to overcharging.

  When the voltage of the capacitor is larger than the second predetermined value, the power control unit may turn on the output of the booster circuit regardless of the voltage of the battery.

  As described above, since the current supplied from the capacitor to the battery is equal to or less than the trickle charge current, the auxiliary charging device of the present invention assumes that power is supplied from the capacitor to the battery even when the battery is fully charged. In addition, battery deterioration due to overcharging can be suppressed. On the other hand, when the voltage of the capacitor exceeds the upper limit withstand voltage, the storage function of the capacitor is significantly deteriorated. Here, when the voltage of the capacitor is larger than the second predetermined value, the configuration in which power is supplied from the capacitor to the battery regardless of the voltage of the battery suppresses the deterioration due to overcharging of the battery, and the performance of the capacitor due to the excessive voltage. Can be avoided.

  When the state where the voltage of the battery is less than the third predetermined value continues for a predetermined time, a low voltage notification unit that notifies that fact may further be provided.

  When the voltage of the capacitor becomes less than the first predetermined value and the supply of power from the capacitor is closed, the power of the battery will eventually be depleted. By notifying that the battery is not storing the power necessary to operate the load device, the user can be notified before using the load by the configuration that notifies that it has become less than the third predetermined value. it can.

  The capacitor may be a lithium ion capacitor. The first predetermined value may be a lower limit withstand voltage of the lithium ion capacitor, and the second predetermined value may be an upper limit withstand voltage of the lithium ion capacitor.

  A lithium ion capacitor has a smaller self-discharge than other electric double layer capacitors, and can store a large amount of electric power. Therefore, it is possible to efficiently supply power to the battery by using the lithium ion capacitor as the capacitor of the auxiliary charging device. Moreover, since the lithium ion capacitor is excellent in high temperature characteristics as compared with other electric double layer capacitors, power can be stably supplied to a battery used in a high temperature environment such as a vehicle battery.

  The battery is a battery mounted on the vehicle, and the auxiliary charging device further includes a key detection unit that detects whether or not the ignition key of the vehicle is on, and the capacitor voltage measurement unit has the ignition key on. The interval for measuring the voltage of the capacitor may be varied based on whether or not there is.

  The fluctuation range of the voltage of the battery varies significantly depending on the use state of the vehicle, for example, whether or not the ignition key is on, and accordingly, the fluctuation of the power supply amount from the capacitor to the battery also varies significantly. Therefore, the processing load is reduced by keeping the voltage measurement frequency low when the ignition key is off, by changing the capacitor voltage measurement interval based on whether or not the ignition key is operating. When the ignition key is on, if the capacitor voltage measurement frequency is kept high, even if the capacitor is suddenly depressurized due to significant battery power consumption, the depressurization can be performed quickly. Can be detected.

  In order to solve the above-mentioned problem, the auxiliary charging method of the present invention is a complementary charging method of charging a battery using a capacitor, converting light energy into electric power, storing the converted electric power in the capacitor, and storing the electric power. Boosting the power, limiting the current supplied from the capacitor to the battery to be less than the trickle charge current of the battery, measuring the voltage of the capacitor, and if the measured voltage of the capacitor is greater than or equal to the first predetermined value, The power is supplied to the battery.

  The components based on the technical idea of the auxiliary charging device described above and the description thereof can also be applied to the auxiliary charging method.

  As described above, the present invention controls power supply from the capacitor to the battery based on the voltage of the capacitor, thereby efficiently and stably supplying power to the battery while avoiding significant deterioration of the capacitor performance. It becomes possible to do.

It is a functional block diagram showing a schematic structure of an auxiliary charging device according to the first embodiment. It is the flowchart which showed the specific process of the auxiliary charge method concerning 1st Embodiment. It is the block diagram which showed the rough connection relation of the auxiliary charging device concerning 2nd Embodiment. It is the functional block diagram which showed the schematic structure of the auxiliary charging apparatus concerning 2nd Embodiment. It is the flowchart which showed the specific process of the auxiliary charge method concerning 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First Embodiment: Auxiliary Charging Device 100)
FIG. 1 is a functional block diagram illustrating a schematic configuration of the auxiliary charging device 100 according to the first embodiment.

  As shown in FIG. 1, the auxiliary charging device 100 includes a solar cell 110, a solar cell voltage measuring unit 112, a capacitor 120, a capacitor voltage measuring unit 122, a booster circuit 130, a battery voltage measuring unit 140, and a central control. Unit 150. The auxiliary charging device 100 is connected to the battery 102, stores and boosts the electric power converted by the solar cell 110 constituting the auxiliary charging device 100, and the electric power is supplied (charged) from the auxiliary charging device 100 to the battery 102. The battery 102 includes a secondary battery such as a lead storage battery or a lithium ion battery.

  The solar cell 110 is composed of a transparent solar cell made of a transparent oxide semiconductor that transmits visible light, or an opaque solar cell such as a crystalline silicon type, an amorphous silicon type, or a compound semiconductor type. The light energy emitted from the light etc. is directly converted into electric power.

  In the solar cell voltage measurement unit 112, the first switch 114 disposed between the solar cell 110 and the backflow prevention diode 116 is opened according to control of the power control unit described later, and the solar cell 110 is unloaded. Then, the voltage (electromotive force) of the solar cell 110 is measured. Then, when the measured voltage of the solar battery 110 is a predetermined value (eg, 2.2 V) or more, an interrupt signal is transmitted to the power control unit.

  Capacitor 120 stores the electric power converted by solar cell 110. In the present embodiment, when the power control unit receives the interrupt signal transmitted by the solar cell voltage measurement unit 112, the power control unit closes the first switch 114. Then, the capacitor 120 starts storing the electric power converted by the solar cell 110. If the solar cell 110 is irradiated with light due to the configuration including the capacitor 120, electric power is stored in the capacitor 120. Therefore, since the auxiliary charging device 100 uses the electric power stored in the capacitor 120 for charging when supplying electric power to the battery 102, the electric power is reliably supplied to the battery 102 even when the solar cell 110 is not irradiated with light. Can be supplied.

  In the present embodiment, the capacitor 120 is composed of an electric double layer capacitor, particularly a lithium ion capacitor.

  A lithium ion capacitor has a smaller self-discharge than other electric double layer capacitors, and can store a large amount of electric power. Therefore, the auxiliary charging apparatus 100 can efficiently supply power to the battery 102 by using a lithium ion capacitor as the capacitor 120. In addition, since lithium ion capacitors have superior high temperature characteristics compared to other electric double layer capacitors, they can stably supply power to batteries used in high temperature environments such as batteries mounted on vehicles. be able to.

  The capacitor voltage measuring unit 122 measures the voltage of the capacitor 120.

  Booster circuit 130 boosts the electric power stored in capacitor 120 and limits the current supplied from capacitor 120 to battery 102 to be equal to or less than the trickle charge current of battery 102. The booster circuit 130 can be configured by a switching regulator or a DC-DC converter. Here, the second switch 124 is disposed between the capacitor 120 and the booster circuit 130, and the third switch 132 is disposed between the booster circuit 130 and the battery 102.

  When the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is less than the first predetermined value, the second switch 124 is opened according to control of the power control unit described later to prevent overdischarge of the capacitor 120. Is done.

  The third switch 132 opens and closes the connection between the battery 102 and the booster circuit 130 according to the control of the power control unit when the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is equal to or higher than the first predetermined value.

  The booster circuit 130 limits the current supplied from the capacitor 120 to the battery 102 to be equal to or less than the trickle charge current of the battery 102, so that the battery 102 is fully charged regardless of the voltage of the battery 102. In addition, the deterioration of the battery 102 due to overcharging can be suppressed.

  The battery voltage measurement unit 140 measures the voltage of the battery 102.

  The central control unit 150 includes a semiconductor integrated circuit including a central processing unit (CPU) and a signal processing unit (DSP: Digital Signal Processor), and manages and controls the entire auxiliary charging device 100 using a predetermined program. In the present embodiment, power is supplied from the battery 102 to the central control unit 150. The central control unit 150 is configured by, for example, the semiconductor integrated circuit described above, and the solar cell 110 converts the power consumption of the central control unit 150. It is desirable to make it sufficiently lower than the power to be used.

  In the present embodiment, the central control unit 150 also functions as the power control unit 152 and the low voltage notification unit 154.

  When the power control unit 152 receives the interrupt signal transmitted by the solar cell voltage measurement unit 112, the power control unit 152 closes the first switch 114. Then, the capacitor 120 starts to store the electric power converted by the solar cell 110.

  In the present embodiment, the power control unit 152 is configured such that the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is equal to or higher than a first predetermined value and equal to or lower than a second predetermined value that is a value equal to or higher than the first predetermined value. Based on the voltage of the battery 102 measured by the battery voltage measuring unit 140, the output of the booster circuit 130 is turned on and off so that the power stored in the capacitor 120 is supplied to the battery 102. For example, if the voltage of the battery 102 is less than the auxiliary charging start voltage (for example, 11.5 V) of the battery 102, the third switch 132 is closed, the output of the booster circuit 130 is turned on, and is larger than the auxiliary charging start voltage. After reaching the auxiliary charging end voltage, the third switch 132 is opened and the output of the booster circuit 130 is turned off until the battery is spontaneously discharged and the voltage becomes lower than the auxiliary charging start voltage.

  Here, the first predetermined value is, for example, the lower limit withstand voltage of the capacitor 120, and the second predetermined value is, for example, the upper limit withstand voltage of the capacitor 120. In the present embodiment, since the capacitor 120 is composed of a lithium ion capacitor, the first predetermined value is 2.2V and the second predetermined value is 3.8V.

  In the present embodiment, the first predetermined value is the lower limit withstand voltage of the capacitor 120. However, the first predetermined value is the minimum necessary for the booster circuit 130 to operate on the assumption that it is equal to or higher than the lower limit withstand voltage of the capacitor 120. The voltage may be the first predetermined value.

  When the voltage of the capacitor 120 is within an allowable range (more than the lower limit withstand voltage of the capacitor and less than or equal to the upper limit withstand voltage), the power control unit 152 supplies the power stored in the capacitor 120 to the battery 102 based on the voltage of the battery 102. Thus, with the configuration in which the output of the booster circuit is turned on and off, the auxiliary charging device 100 can appropriately and efficiently supply power from the capacitor 120 to the battery 102 while reliably avoiding deterioration of the battery 102 due to overcharging. It becomes possible.

  In the present embodiment, the power control unit 152 outputs the output of the booster circuit 130 regardless of the voltage of the battery 102 when the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is larger than the second predetermined value (upper limit withstand voltage). On, that is, the third switch 132 is closed.

  As described above, the booster circuit 130 limits the current supplied from the capacitor 120 to the battery 102 to be equal to or less than the trickle charge current, so that power is supplied from the capacitor 120 to the battery 102 even when the battery 102 is fully charged. Even if it is done, deterioration of the battery 102 due to overcharging can be suppressed. On the other hand, when the voltage of capacitor 120 exceeds the upper limit withstand voltage (second predetermined value), the power storage function of capacitor 120 is significantly degraded. Here, when the voltage of the capacitor 120 is larger than the second predetermined value, the power is supplied from the capacitor 120 to the battery 102 regardless of the voltage of the battery 102, thereby suppressing the deterioration due to overcharging of the battery 102 and excessively. It is possible to avoid a situation in which the performance of the capacitor 120 is significantly degraded by the voltage.

  Furthermore, in this embodiment, the power control unit 152 electrically connects the booster circuit 130 from the capacitor 120 when the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is less than a first predetermined value (lower limit withstand voltage of the capacitor 120). Disconnect. Here, the power controller 152 electrically disconnects the booster circuit 130 from the capacitor 120 by opening the second switch 124.

  Further, when the booster circuit 130 has a separate power supply terminal, the power control unit 152 may electrically disconnect the booster circuit 130 from the capacitor 120 by stopping the supply of power to the power supply terminal. If the power supplied to the booster circuit 130 is stopped, the operation of the booster circuit 130 can be stopped and the discharge of the capacitor 120 can be suppressed.

  When the voltage of the capacitor 120 according to the present embodiment is less than the first predetermined value (lower limit withstand voltage), the auxiliary charging device 100 has a minimum power storage function of the capacitor 120 by electrically disconnecting the booster circuit 130 from the capacitor 120. The supply of electric power from the capacitor 120 to the battery 102 can be stopped before the voltage becomes lower than the necessary voltage. Therefore, regardless of the voltage of the battery 102 or the conversion efficiency of the solar battery 110, the capacitor 120 can reliably maintain the minimum voltage necessary for the power storage function.

  When the state where the voltage of the battery 102 measured by the battery voltage measurement unit 140 is lower than a third predetermined value (for example, 11.5 V) continues for a predetermined time, the low voltage notification unit 154 is set every predetermined interval (for example, 1 hour). In addition, a lamp (not shown) such as an LED is turned on for a predetermined time (for example, 1 minute) or a sound is output from a speaker (not shown) for a predetermined time (for example, 1 minute). The user is notified that the voltage is less than the third predetermined value.

  When the voltage of the capacitor 120 is attenuated to the first predetermined value and the supply of power from the capacitor 120 is closed, the power of the battery 102 is eventually depleted. With the configuration for notifying that the value is less than the third predetermined value, it is possible to notify the user that the battery 102 does not store the power necessary for operating the load before using the load.

  As described above, according to the auxiliary charging device 100 of the present embodiment, the power supply from the capacitor 120 to the battery 102 is controlled based on the voltage of the capacitor 120, thereby avoiding significant deterioration in the performance of the capacitor 120. However, power can be supplied to the battery 102 efficiently and stably.

(Supplementary charging method)
A supplementary charging method using the above-described supplementary charging apparatus 100 is also provided. FIG. 2 is a flowchart showing specific processing of the auxiliary charging method according to the first embodiment.

  First, the solar cell 110 converts light energy into electric power (S200), and when the first switch 114 is opened according to the control by the power control unit 152, the solar cell voltage measurement unit 112 changes the voltage of the solar cell 110. Measurement is performed (S202), and it is determined whether or not the measured voltage is a predetermined value or more (S204). If the voltage of the solar cell 110 is equal to or higher than the predetermined value (YES in S204), the solar cell voltage measurement unit 112 transmits an interrupt signal to the power control unit 152 (S206). The power control unit 152 that has received the interrupt signal closes the first switch 114 to connect the solar cell 110 and the capacitor 120, and the capacitor 120 starts storing the power converted by the solar cell 110, and the power control unit 152 resets the battery flag (to 0) (S208).

  The capacitor voltage measurement unit 122 measures the voltage of the capacitor 120 (S210), and the power control unit 152 determines whether the voltage of the capacitor 120 measured by the capacitor voltage measurement unit 122 is less than a first predetermined value. Is determined (S212). When the voltage of the capacitor 120 is less than the first predetermined value (YES in S212), the power control unit 152 stops the supply of power from the capacitor 120 to the battery 102 regardless of the voltage of the battery 102. The second switch 124 is opened to electrically disconnect the booster circuit 130 from the capacitor 120 (S232).

  If the voltage of capacitor 120 is greater than or equal to the first predetermined value (NO in S212), power control unit 152 determines whether or not the voltage of capacitor 120 measured by capacitor voltage measurement unit 122 is greater than a second predetermined value. (S214) When the voltage of the capacitor 120 is greater than the second predetermined value (YES in S214), the third power is stored in the capacitor 120 so that the power stored in the capacitor 120 is supplied to the battery 102 regardless of the voltage of the battery 102. The switch 132 is closed and the output of the booster circuit 130 is turned on (S230).

  When the voltage of the capacitor 120 is less than or equal to the second predetermined value (NO in S214), the battery voltage measurement unit 140 measures the voltage of the battery 102 (S216), and the power control unit 152 determines whether the battery It is determined whether or not the power for one day's natural discharge of 102 is supplied from the capacitor 120 (S218), and if it is supplied (YES in S218), the power control unit 152 sends power from the capacitor 120 to the battery 102. The third switch 132 is opened to turn off the output of the booster circuit 130 so that the supply of power is stopped (S232).

  On the other hand, when the electric power for one day natural discharge of the battery 102 is not supplied from the capacitor 120 (NO in S218), the power control unit 152 determines whether or not the voltage of the battery 102 is smaller than the auxiliary charging start voltage. If the voltage of the battery 102 is less than the auxiliary charging start voltage (YES in S220), the battery flag is set to 1 (S222). When the voltage of the battery 102 is larger than the auxiliary charging start voltage (NO in S220), the power control unit 152 determines whether or not the voltage of the battery 102 exceeds the auxiliary charging end voltage (S224). If the voltage of battery 102 exceeds the auxiliary charging end voltage (YES in S224), power control unit 152 sets the battery flag to 0 (S226), and if not higher (NO in S224), Do not make any changes.

  Then, the power control unit 152 determines whether or not the battery flag is 1 (S228). If the battery flag is 1 (YES in S228), the power control unit 152 is stored in the capacitor 120. The third switch 132 is closed and the output of the booster circuit 130 is turned on so that electric power is supplied to the battery 102 (S230). If the battery flag is not 1, that is, if the battery flag is 0 (NO in S228), the power control unit 152 causes the third switch 132 to stop supplying power from the capacitor 120 to the battery 102. And the output of the booster circuit 130 is turned off (S232).

  The natural discharge determination step S218 may be omitted, and the battery charge measurement step S216 to the auxiliary charge start voltage determination step S220 may be performed.

  When the natural discharge determination step S218 is omitted, the power control unit 152 causes the capacitor 120 to pass the capacitor 120 if the voltage of the capacitor 120 is equal to or higher than the first predetermined value (NO in S212) and the battery flag is 1 (YES in S228). The third switch 132 is closed and the output of the booster circuit 130 is kept on so that the stored electric power is supplied to the battery 102.

  In addition, when the natural discharge determination step S218 is omitted, the power control unit 152 supplies the power stored in the capacitor 120 to the battery 102 even when the voltage of the capacitor 120 is larger than the second predetermined value (YES in S214). As described above, the third switch 132 is closed and the output of the booster circuit 130 is kept on.

(Second Embodiment)
FIG. 3 is a block diagram showing a schematic connection relationship of the auxiliary charging device 300 according to the second embodiment. As shown in FIG. 3, the auxiliary charging device 300 is connected to the battery 102 installed in the vehicle 104 or the like, and stores and boosts the electric power converted by the solar cells constituting the auxiliary charging device 300, thereby Is supplied (charged) to the battery 102. The battery 102 includes a secondary battery such as a lead storage battery or a lithium ion battery.

  When the engine of the vehicle 104 is not operated for a long period of time, for example in winter when the vehicle is a leisure motorcycle, the battery 102 is not charged and the battery 102 is significantly decompressed by natural discharge. . At this time, when the auxiliary charging device 300 according to the present embodiment and the battery 102 of the vehicle 104 are connected, even if the engine is stopped according to the sunlight irradiation state, the sun constituting the auxiliary charging device 300 The electric power converted by the battery can be supplied to the battery 102. Therefore, even if the engine of the vehicle 104 is not operated for a long time, the voltage of the battery 102 can be maintained at an operable voltage, and a situation in which the engine becomes inoperable can be avoided.

  Hereinafter, a specific configuration of the auxiliary charging device 300 according to the present embodiment will be described.

(Auxiliary charging device 300)
FIG. 4 is a functional block diagram showing a schematic configuration of the auxiliary charging device 300 according to the second embodiment.

  As shown in FIG. 4, the auxiliary charging device 300 includes a solar cell 110, a solar cell voltage measurement unit 112, a capacitor 120, a capacitor voltage measurement unit 122, a booster circuit 130, a battery voltage measurement unit 140, And a control unit 350. In addition, about the component substantially equivalent to the auxiliary charging apparatus 100 of 1st Embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The central control unit 350 is configured by a semiconductor integrated circuit including, for example, a central processing unit (CPU) and a signal processing unit (DSP), and manages and controls the entire auxiliary charging device 300 using a predetermined program. In the present embodiment, power is supplied from the battery 102 to the central control unit 350, but the central control unit 150 is configured by, for example, the semiconductor integrated circuit described above, and the solar cell 110 converts the power consumption of the central control unit 150. It is desirable to make it sufficiently low compared to electric power.

  In the present embodiment, the central control unit 350 also functions as the power control unit 152, the low voltage notification unit 154, and the key detection unit 352. Also here, about the component substantially equivalent to the auxiliary charging apparatus 100 of 1st Embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The key detection unit 352 detects whether or not the ignition key of the vehicle 104 is on.

  In the present embodiment, the capacitor voltage measurement unit 122 varies the interval at which the voltage of the capacitor 120 is measured based on whether or not the ignition key of the vehicle 104 detected by the key detection unit 352 is on. In the present embodiment, when the key detection unit 352 detects that the ignition key is on, the capacitor voltage measurement unit 122 sets the measurement interval of the voltage of the capacitor 120 to, for example, one minute interval, and the key detection unit 352 When it is detected that the ignition key is off, the capacitor voltage measurement unit 122 sets the measurement interval of the voltage of the capacitor 120 to, for example, one day interval.

  In the present embodiment, the battery voltage measurement unit 140 varies the interval at which the voltage of the battery 102 is measured based on whether or not the ignition key of the vehicle 104 detected by the key detection unit 352 is on. In this embodiment, when the key detection unit 352 detects that the ignition key is on, the battery voltage measurement unit 140 sets the measurement interval of the voltage of the battery 102 to, for example, one minute interval, and the key detection unit 352 When it is detected that the ignition key is off, the battery voltage measurement unit 140 sets the measurement interval of the voltage of the battery 102 to, for example, one day interval.

  In the present embodiment, the low voltage notification unit 154 determines whether the voltage of the battery 102 is a third predetermined value (for example, 11) based on whether or not the ignition key of the vehicle 104 detected by the key detection unit 352 is on. The duration of the state in which the voltage of the battery 102 is less than the third predetermined value, which is determined when the user is notified that the voltage is less than 5 V), is varied.

  When the key detection unit 352 detects that the ignition key is on, the low voltage notification unit 154 has a state where the voltage of the battery 102 measured by the battery voltage measurement unit 140 is less than the third predetermined value, for example, 10 In the case of continuing for a minute, a lamp such as an LED (not shown) is lit for a predetermined time (for example, 1 minute) or a sound is output from a speaker (not shown) for a predetermined time (for example, 1 hour). For example, for 1 minute) to notify the user that the voltage of the battery 102 is less than the third predetermined value.

  In addition, when the key detection unit 352 detects that the ignition key is off, the low voltage notification unit 154 indicates that the voltage of the battery 102 measured by the battery voltage measurement unit 140 is less than the third predetermined value. For example, when it continues for 5 days, a lamp (not shown) such as an LED is turned on for a predetermined time (for example, 1 minute) or a sound is emitted from a speaker (not shown) at a predetermined interval (for example, 1 hour). The time is output (for example, for 1 minute) to notify the user that the voltage of the battery 102 is less than the third predetermined value.

  When the auxiliary charging device 300 is connected to the battery 102 of the vehicle 104, the voltage fluctuation range of the battery 102 varies significantly depending on the usage state of the vehicle 104, for example, whether or not the ignition key is on. The fluctuations in the amount of power supplied to are also significantly different.

  For example, a motorcycle has a structure in which a driving headlight or a passing headlight is always lit when a prime mover (engine) is operating in a notification that defines details of safety standards for road transport vehicles. It is stipulated. In addition, recent motorcycles often use a so-called keyless entry system in which an ignition key is turned on and off by pressing a button without inserting a key into the cylinder, so that the engine is stopped. In many cases, when the ignition key is on, the driving headlight or the passing headlight is turned on. When the vehicle 104 is such a two-wheeled vehicle, the power consumption of the battery 102 becomes extremely intense when the ignition key is on.

  Therefore, the voltage measurement frequency is kept low when the ignition key is off by the configuration in which the capacitor voltage measurement unit 122 varies the voltage measurement interval of the capacitor 120 based on whether or not the ignition key is on. As a result, the processing load can be reduced. Further, when the ignition key is on, if the voltage measurement frequency of the capacitor 120 is kept high, the power of the battery 102 is significantly consumed, and even if the capacitor 120 is suddenly depressurized, the depressurization is reduced. It becomes possible to detect quickly.

(Supplementary charging method)
A supplementary charging method using the above-described supplementary charging apparatus 300 is also provided. FIG. 5 is a flowchart showing specific processing of the auxiliary charging method according to the present embodiment. The processes that are substantially the same as the auxiliary charging method of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 5, when the capacitor 120 starts to store electricity (S200 to S208), the key detection unit 352 detects whether the ignition key of the vehicle 104 is on or off (S400). The key detection unit 352 determines whether or not the ignition key is on (S402). If the key detection unit 352 determines that the ignition key is not on (NO in S402), whether or not one day has elapsed since the previous measurement. If it is determined (S404) and has elapsed (YES in S404), voltage measurement processing S210 to S224 by the capacitor voltage measurement unit 122 and the battery voltage measurement unit 140 is started, and the voltage of the capacitor 120 is less than the first predetermined value. In some cases, regardless of the voltage of the battery 102, the power control unit 152 opens the second switch 124 so that the supply of power from the capacitor 120 to the battery 102 is stopped, thereby electrically connecting the booster circuit 130 from the capacitor 120. Separate. As in the first embodiment, the spontaneous discharge determination step S218 may be omitted, and the auxiliary charge start voltage determination step S220 may be performed from the battery voltage measurement step S216.

  On the other hand, if it is determined that the ignition key is on (YES in S402), it is determined whether 1 minute has elapsed since the previous measurement (S406). If it has elapsed (YES in S406), the capacitor voltage When the voltage measurement processing S210 to S224 by the measurement unit 122 and the battery voltage measurement unit 140 is started and the voltage of the capacitor 120 is less than the first predetermined value, the power control unit 152 sets the capacitor 120 regardless of the voltage of the battery 102. The second switch 124 is opened so that the supply of power to the battery 102 is stopped, and the booster circuit 130 is electrically disconnected from the capacitor 120.

  As described above, according to the auxiliary charging device 300 according to the present embodiment, the capacitor voltage measurement unit 122 varies the voltage measurement interval of the capacitor 120 based on whether or not the ignition key is on. Thus, when the ignition key is off, the processing load can be reduced by keeping the voltage measurement frequency low. In addition, when the ignition key is on, if the voltage measurement frequency of the capacitor 120 is kept high, the battery power is significantly consumed, so that even if the capacitor 120 is suddenly depressurized, the depressurization is reduced. It becomes possible to detect quickly.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the embodiment described above, the power control unit 152 closes and opens the third switch 132 to turn on and off the output of the booster circuit 130. However, the present invention is not limited to this, and closes and opens the second switch 124. Thus, the output of the booster circuit 130 may be turned on / off. In this case, the auxiliary switch 100 need not be provided with the third switch 132.

  When the booster circuit 130 has a separate output control terminal, the power control unit 152 may turn on and off the output through the output control terminal. Also in this case, the auxiliary switch 100 need not be provided with the third switch 132.

  Note that each step in the supplementary charging method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine.

  INDUSTRIAL APPLICABILITY The present invention can be used for an auxiliary charging device and an auxiliary charging method for supplying electric power generated by a solar cell to a battery.

DESCRIPTION OF SYMBOLS 100, 300 ... Auxiliary charging apparatus 102 ... Battery 104 ... Vehicle 110 ... Solar cell 112 ... Solar cell voltage measurement part 120 ... Capacitor 122 ... Capacitor voltage measurement part 130 ... Booster circuit 140 ... Battery voltage measurement part 152 ... Power control part 352 ... Key detector

Claims (10)

An auxiliary charging device for charging a battery,
A solar cell that converts light energy into electric power;
A capacitor for storing electric power converted by the solar cell;
A step-up circuit for stepping up electric power stored in the capacitor and limiting a current supplied from the capacitor to the battery to a trickle charge current of the battery;
A capacitor voltage measuring unit for measuring the voltage of the capacitor;
A power control unit that turns on the output of the booster circuit so that the power stored in the capacitor is supplied to the battery when the voltage of the capacitor is equal to or higher than a first predetermined value;
An auxiliary charging device comprising:   2. The auxiliary charging device according to claim 1, wherein the power control unit electrically disconnects the booster circuit from the capacitor when a voltage of the capacitor is less than a first predetermined value. The auxiliary charging device further includes a battery voltage measuring unit that measures the voltage of the battery,
When the voltage of the capacitor is equal to or higher than the first predetermined value and equal to or lower than a second predetermined value that is equal to or higher than the first predetermined value, the power control unit is configured to control the boost circuit based on the voltage of the battery. The auxiliary charging device according to claim 1, wherein the output is turned on and off.   4. The auxiliary charging device according to claim 3, wherein when the voltage of the capacitor is larger than the second predetermined value, the power control unit turns on the output of the booster circuit regardless of the voltage of the battery. 5. .   5. The low-voltage notification unit according to claim 1, further comprising a low-voltage notification unit that notifies the fact that the state in which the voltage of the battery is less than a third predetermined value continues for a predetermined period of time. Auxiliary charging device.   The auxiliary charging device according to claim 1, wherein the capacitor is a lithium ion capacitor.   The auxiliary charging device according to claim 6, wherein the first predetermined value is a lower limit withstand voltage of the lithium ion capacitor.   The auxiliary charging device according to claim 6 or 7, wherein the second predetermined value is an upper limit withstand voltage of the lithium ion capacitor. The battery is a battery mounted on a vehicle,
The auxiliary charging device further includes a key detection unit that detects whether or not an ignition key of the vehicle is on,
The said capacitor voltage measurement part changes the space | interval which measures the voltage of the said capacitor based on whether the said ignition key is ON, The any one of Claim 1 to 8 characterized by the above-mentioned. Auxiliary charging device. A supplementary charging method for charging a battery using a capacitor,
Convert light energy into electricity,
Storing the converted electric power in a capacitor;
Boosting the stored power, limiting the current supplied from the capacitor to the battery to be less than or equal to the trickle charge current of the battery
Measuring the voltage of the capacitor;
When the measured voltage of the capacitor is equal to or higher than a first predetermined value, the power stored in the capacitor is supplied to the battery.

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