WO2014054380A1

WO2014054380A1 - Charger having power generator

Info

Publication number: WO2014054380A1
Application number: PCT/JP2013/074096
Authority: WO
Inventors: 康彦神崎; 牧広小林; 秀夫川嶌; 健也 ▲柳▼原
Original assignee: 株式会社マキタ
Priority date: 2012-10-04
Filing date: 2013-09-06
Publication date: 2014-04-10

Abstract

A charger charges a battery pack of an electric device. The charger is provided with an engine, a power generator, and a battery mounting part. The power generator is driven by the engine. The battery pack is mountable to and demountable from the battery mounting part, and the battery mounting part outputs electric power from the power generator to the battery pack. As the engine, a relatively small-sized one can be used, and for example, an engine having a displacement of 25 ml or less can be used.

Description

Charger with generator

The technology disclosed herein relates to a charger that charges a battery pack of an electric device.

Electrical devices that use battery packs as a power source are widely used. Such an electric device can be used without being connected to an external power source by precharging the battery pack. The battery pack is charged by a charger. Japanese Patent Laying-Open No. 2005-295750 describes a conventional charger.

The conventional charger is used connected to a commercial power source. Therefore, the battery pack cannot be charged when the commercial power source is not available, for example, during a power failure. In such a case, it is conceivable to use a portable power generator instead of the commercial power source. A portable power generation device moves a generator by an engine and outputs the same AC power (for example, AC 100 volts) as a commercial power source. Therefore, it can be used as a power source for the charger. However, the general-purpose power generator has an excessive capacity as a power source for the charger, and there is a problem in that energy efficiency is poor when such a power generator is used.

In view of the above-described problems, the technology disclosed in the present specification aims to provide a charger that does not require an external power source.

This specification provides a charger for charging a battery pack of an electric device. The charger includes an engine, a generator, and a battery mounting portion. The generator is driven by the engine. The battery mounting part is detachable from the battery pack, and outputs power from the generator to the battery pack.

Since the charger has an engine and a generator, the battery pack of the electronic device can be charged without requiring an external power source. Since the engine and the generator need only generate electric power required for charging the battery pack, relatively small ones can be employed. Since the electric power generated by the generator can be directly supplied to the battery pack without converting it to a high voltage like a commercial power supply, it also has an advantage of high energy efficiency.

The charger of Example 1 is shown typically. The structure of the electric power generation unit of Example 1 is shown typically. The electrical structure of the charging unit using the 1st charging unit is shown. The block diagram which shows the electric constitution of a 2nd charging unit. A parallel connection circuit is shown. A series connection circuit is shown. The electrical structure of the charger of Example 2 is shown (a part is omitted). The electrical structure of the charger of Example 3 is shown. The connection switching circuit at the time of parallel connection is shown. The connection switching circuit at the time of series connection is shown.

In one embodiment of the present technology, the engine may have a displacement of 25 milliliters or less, and more preferably, a displacement of 5 milliliters or more and 20 milliliters or less. Even such a small engine can sufficiently generate electric power necessary for charging the battery pack.

In one embodiment of the present technology, the generator is preferably an AC generator. In this case, it is preferable that the charger further includes a rectifier circuit provided between the generator and the battery mounting portion. Note that a DC generator may be employed instead of the AC generator or together with the AC generator.

In one embodiment of the present technology, it is preferable that the charger further includes a cutoff switch. This cutoff switch is provided between the generator and the battery mounting portion, and cuts off power supply from the engine to the battery mounting portion. By providing the cutoff switch, the charging of the battery pack can be stopped immediately if necessary.

In one embodiment of the present technology, it is preferable that the maximum generated voltage of the generator is 42 volts or less. By setting the maximum generated voltage small, a relatively small engine or generator can be employed.

In one embodiment of the present technology, it is preferable that the charger fully charges a battery having a nominal voltage of 18 volts and a capacity of 3 ampere hours within 15 minutes to 30 minutes from the state where the remaining capacity is zero. According to such a configuration, it is possible to charge the battery pack in a relatively short time while suppressing the burden on the battery pack.

In one embodiment of the present technology, it is preferable that the engine can be started by a power tool. Although the structure for that is not specifically limited, For example, an electric tool can be connected to the crankshaft of the engine, and the engine can be started by rotating the crankshaft with the electric tool. Or it is good also as a structure which provides the 2nd generator driven with an electric tool, and a starter motor starts an engine with the electric power generated by the 2nd generator.

In one embodiment of the present technology, the charger preferably further includes a detection unit and a control unit. A detection part detects the state parameter | index which shows the state of the battery pack attached to the battery attachment part. The control unit adjusts the output of the engine based on the detection value by the detection unit. According to such a configuration, it is possible to perform power generation without excess or deficiency with respect to the charging power required for charging the battery pack, and it is possible to suppress unnecessary energy consumption.

In one embodiment of the present technology, it is preferable that the control unit adjusts the output of the engine by adjusting a fuel supply amount to the engine. According to such a configuration, the output of the engine can be adjusted with high accuracy.

In one embodiment of the present technology, it is preferable that the charger further includes a carburetor that mixes fuel with air supplied to the engine. In this case, the control unit preferably adjusts the engine output by adjusting the throttle opening of the carburetor.

In the above-described embodiment, it is preferable that the charger further includes an actuator that is connected to the throttle of the carburetor and adjusts the opening of the throttle. In this case, the control unit can control the output of the engine by controlling the actuator.

In one embodiment of the present technology, it is preferable that the control unit stores a target value related to the state index, and adjusts the output of the engine according to the magnitude relationship between the detection value detected by the detection unit and the target value. According to such a configuration, for example, when the detected value is larger than the target value, the engine output can be reduced, and when the detected value is smaller than the target value, the engine output can be increased. Thereby, the battery pack can be charged while maintaining the battery pack in an appropriate state.

In one embodiment of the present technology, it is preferable that the state index includes at least one of a charging current of the battery pack, a charging voltage of the battery pack, and a temperature of the battery pack. By monitoring these indexes, it is possible to prevent an excessive burden on the battery pack being charged.

In one embodiment of the present technology, the power generator includes at least one first power generation coil and at least one second power generation coil, and the first power generation coil and the second power generation coil are connected in parallel. It is preferable that power is generated with a power generation voltage of 1, and when the first power generation coil and the second power generation coil are connected in series, power is generated with a second power generation voltage higher than the first power generation voltage. According to such a configuration, the generated voltage can be switched according to the characteristics (particularly the nominal voltage) of the battery pack to be charged.

In an embodiment of the present technology, it is preferable to further include a first unit and a second unit that can be selectively attached to the generator. In this case, it is preferable that the first unit has a parallel connection circuit that connects the first power generation coil and the second power generation coil in parallel. The second unit preferably has a series connection circuit that connects the first power generation coil and the second power generation coil in series. According to such a configuration, when charging a battery pack having a low nominal voltage, the first generator coil and the second generator coil can be connected in parallel by using the first unit. When charging a battery pack having a high nominal voltage, the first generator coil and the second generator coil can be connected in series by using the second unit.

In one embodiment of the present technology, it is preferable that the battery attachment portion includes a first battery attachment portion and a second battery attachment portion. In this case, it is preferable that the 1st battery attachment part is provided in the 1st unit, and is comprised so that the 1st battery pack which has a 1st nominal voltage may be received. The second battery mounting portion is preferably provided in the second unit and configured to receive a second battery pack having a second nominal voltage higher than the first nominal voltage. According to such a structure, when charging a 1st battery pack, it can avoid using a 2nd unit accidentally. Similarly, when the second battery pack is charged, it can be avoided that the first unit is used by mistake.

In the above-described embodiment, the first unit has the first control unit that adjusts the charging current of the first battery pack, and the second unit has the second control unit that adjusts the charging current of the second battery pack. It is preferable. Since each unit has a control unit, it is possible to appropriately charge each of the first battery pack and the second battery pack.

Alternatively, in another embodiment, the charger preferably includes a connection switching circuit provided between the generator and the battery mounting portion. In this case, the connection switching circuit selects a parallel connection circuit that connects the first power generation coil and the second power generation coil in parallel, and a series connection circuit that connects the first power generation coil and the second power generation coil in series. Preferably, it is formed. Switching between parallel and series by the connection switching circuit may be performed automatically by a charger or manually by a user.

In one embodiment of the present technology, it is preferable that the charger further includes a stop control unit that outputs a signal for stopping the engine based on a signal output from a battery pack attached to the battery mounting unit. According to such a configuration, when any abnormality occurs in the battery pack, the engine can be stopped to stop charging. By using a signal output from the battery pack, chargers corresponding to various battery packs can be simply configured.

In the above-described embodiment, the charge stop signal is preferably a signal output from the battery pack when at least one of the charging voltage, charging current, and temperature of the battery pack is outside a predetermined allowable range. According to such a configuration, it is possible to prevent the charging from being continued while the battery pack is easily damaged.

It is preferable that the stop control unit described above includes a first stop control unit and a second stop control unit that operate independently of each other. In this case, it is preferable that each of the first stop control unit and the second stop control unit outputs the engine stop signal based on a signal output from a battery pack attached to the battery attachment unit. By having two stop control units, the battery pack can be protected even when an abnormality occurs in one of the stop control units.

It is preferable that the stop control unit described above can detect the charging voltage of the battery pack and also outputs the engine stop signal even when the detected charging voltage is out of a predetermined allowable range. According to such a configuration, even when the battery pack cannot output the engine stop signal, the battery pack can be appropriately charged.

In one embodiment of the present technology, it is preferable that the charger further includes an ignition unit that controls ignition of the engine. In this case, it is preferable that the ignition unit stops the ignition of the engine when the engine stop signal is received. By stopping the ignition of the engine, the engine can be stopped reliably.

The technology disclosed in this specification can be applied to battery pack chargers of various electric devices including electric tools, digital cameras, mobile phones, smartphones, tablets, electric assist bicycles, electric motorcycles, and toys. .

In one embodiment of the present technology, various engines including a two-stroke engine, a four-stroke engine, a rotary engine, and a Stirling engine can be adopted as a prime mover of the generator.

FIG. 1 schematically shows a charger 10 of the embodiment. The charger 10 can charge two types of

battery packs

18a and 18b. The battery packs 18a and 18b are battery packs for an electric tool that is a kind of electric equipment. The first battery pack 18a and the second battery pack 18b that are configured to be detachable from the electric tool have different nominal values. Has voltage. In this embodiment, the nominal voltage of the first battery pack 18a is 18 volts, and the nominal voltage of the second battery pack 18b is 36 volts. However, the nominal voltages of the first battery pack 18a and the second battery pack 18b are not limited to these values.

As shown in FIG. 1, the charger 10 includes a power generation unit 12, a first charging unit 14a, and a second charging unit 14b. The first charging unit 14 a and the second charging unit 14 b can be selectively attached to the power generation unit 12. When charging the first battery pack 18a, the first charging unit 14a is attached to the power generation unit 12, and when charging the second battery pack 18b, the second charging unit 14b is replaced with the first charging unit 14a. It is attached to the power generation unit 12. The first charging unit 14a is provided with a first battery mounting portion 16a. The 1st battery attachment part 16a is comprised so that the 1st battery pack 18a can be attached or detached. On the other hand, the 2nd battery attachment part 16b is provided in the 2nd charging unit 14b. The second battery mounting portion 16b is configured such that the second battery pack 18b is detachable.

The configuration of the power generation unit 12 will be described with reference to FIG. As shown in FIG. 2, the power generation unit 12 includes an engine 38, a fuel tank 56, a carburetor 42, a servo motor 52, and an ignition unit 48. The engine 38 is provided with a spark plug 40 for igniting the fuel. The engine 38 rotates the output shaft 36 by burning fuel. The form of the engine 38 is not particularly limited. For example, the engine 38 may be various engines including a 2-stroke engine, a 4-stroke engine, a rotary engine, and a Stirling engine. As an example, the engine 38 of the present embodiment is a two-stroke engine. The displacement of the engine 38 is not particularly limited. The displacement of the engine 38 can be appropriately selected according to the capacity required for charging the battery packs 18a and 18b. For example, in the case of

battery packs

18a and 18b for electric tools with a nominal voltage of 50 volts or less, a small engine with a displacement of 25 milliliters or less can be employed. In particular, when the nominal voltage is 10 volts or more and 36 volts or less, the displacement of the engine 38 can be 5 ml or more and 20 ml or less. In addition, when determining the displacement of the engine 38, it is preferable to consider the capacity of the battery packs 18a and 18b.

The fuel of the engine 38 is stored in the fuel tank 56. The fuel in the fuel tank 56 is supplied to the engine 38 by a carburetor. The carburetor 42 mixes the fuel sucked from the fuel tank 56 with the air supplied to the engine 38. The carburetor 42 is provided with a throttle 44 that adjusts the amount of air supplied to the engine 38. The throttle 44 is connected to the servo motor 52 via a link 54. The servo motor 52 is an actuator that adjusts the opening degree of the throttle 44. The ignition unit 48 is connected to the spark plug 40 via the plug cord 50. The ignition unit 48 intermittently supplies a high voltage to the spark plug 40 in synchronization with the rotation of the engine 38. Thereby, the ignition timing of the engine 38 is controlled. When the ignition unit 48 stops supplying the voltage to the spark plug 40, the engine 38 also stops.

The power generation unit 12 includes a generator 34. The generator 34 is connected to the output shaft 36 of the engine 38 and is driven by the engine 38. The generator 34 is a three-phase AC generator and generates three-phase AC power when driven by the engine 38. The electric power generated by the generator 34 is sent to the first or

second charging unit

14a, 14b and used for charging the battery packs 18a, 18b. A cooling fan 32 is provided on the output shaft 36. The cooling fan 32 rotates and sends cooling air to the generator 34 and the engine 38. A spinner 30 is fixed to the tip of the output shaft 36. The generator 34 may be a single-phase AC generator or a DC generator, and the type of the generator 34 is not particularly limited.

The spinner 30 is provided with a tool engaging portion 30a. The tool engaging portion 30a has a hexagonal column shape. The tool engaging portion 30a is formed to imitate the shape of a hexagon nut, and can engage a general-purpose electric tool. The output shaft 36 (ie, the crankshaft of the engine 38) can be rotated by a power tool, thereby starting the engine 38.

The configuration of the first charging unit 14a and the second charging unit 14b will be described with reference to FIGS. As shown in FIG. 3, the first charging unit 14a includes a parallel connection circuit 62a, a rectifier circuit 64, a cutoff switch 68, a current detection circuit 70, a positive output terminal 72, a negative output terminal 74, a communication terminal 76, a controller 78, and An overcharge monitoring circuit 80 is provided. The parallel connection circuit 62 a is electrically connected to the rectifier circuit 64, and the rectifier circuit 64 is connected to the positive output terminal 72 and the negative output terminal 74 via the cutoff switch 68 and the current detection circuit 70.

The positive output terminal 72, the negative output terminal 74, and the communication terminal 76 are provided in the 1st battery attachment part 16a. When the first battery pack 18a is attached to the first battery attachment portion 16a, the positive output terminal 72 and the negative output terminal 74 are electrically connected to the plurality of battery cells 20 in the first battery pack 18a. The communication terminal 76 is communicably connected to the battery controller 22 in the first battery pack 18a.

On the other hand, as shown in FIG. 4, the second charging unit 14b includes a series connection circuit 62b, a rectifier circuit 64, a cutoff switch 68, a current detection circuit 70, a positive output terminal 72, a negative output terminal 74, a communication terminal 76, and a controller 78. , And an overcharge monitoring circuit 80. The series connection circuit 62 b is electrically connected to the rectifier circuit 64, and the rectifier circuit 64 is connected to the positive output terminal 72 and the negative output terminal 74 via the cutoff switch 68 and the current detection circuit 70.

The positive output terminal 72, the negative output terminal 74, and the communication terminal 76 are provided in the second battery mounting portion 16b. When the second battery pack 18b is attached to the second battery attachment portion 16b, the positive output terminal 72 and the negative output terminal 74 are electrically connected to the plurality of battery cells 20 in the second battery pack 18b. The communication terminal 76 is communicably connected to the battery controller 22 in the second battery pack 18b.

As is clear by comparing FIG. 3 and FIG. 4, the first charging unit 14a and the second charging unit 14b basically have a common configuration. However, the first charging unit 14a is different from the second charging unit 14b in that it includes a parallel connection circuit 62a instead of the series connection circuit 62b. The series connection circuit 62b and the parallel connection circuit 62a will be described with reference to FIGS. As shown in FIGS. 5 and 6, the generator 34 of the present embodiment has a first coil group 92 and a second coil group 94. The first coil group 92 includes a plurality of coils including a U-phase coil, a V-phase coil, and a W-phase coil, and the second coil group 94 includes a plurality of coils including a U-phase coil, a V-phase coil, and a W-phase coil. Including. As shown in FIG. 5, the parallel connection circuit 62a connects two

coil groups

92 and 94 in parallel. In this case, the maximum generated voltage by the generator 34 is about 21 volts. On the other hand, as shown in FIG. 6, the series connection circuit 62b connects two

coil groups

92 and 94 in series. In this case, the maximum generated voltage by the generator 34 is about 42 volts.

As described above, the first charging unit 14a is used for charging the first battery pack 18a having a low nominal voltage. Therefore, in the 1st charging unit 14a, the power generation voltage by the generator 34 is made low by connecting the two

coil groups

92 and 94 of the generator 34 in parallel. In this case, since the output current of the generator 34 increases by connecting the two

coil groups

92 and 94 in parallel, the charging time can be shortened. On the other hand, the second charging unit 14b is used for charging the second battery pack 18b having a high nominal voltage. Therefore, in the 2nd charging unit 14b, the power generation voltage by the generator 34 is made high by connecting two

coil groups

92 and 94 of the generator 34 in series. Thus, in the charger 10 according to the present embodiment, the power generation voltage by the generator 34 is changed according to the charging

units

14a and 14b to be used. Thereby, the battery packs 18a and 18b having different nominal voltages can be charged by the single generator 34 without requiring a circuit such as a switching power supply.

The generator 34 of the present embodiment is a three-phase AC generator, but the generator 34 may be a single-phase AC generator. Even in this case, the generator 34 has at least two coils, and the power generated by the generator 34 can be changed by switching the connection mode between series and parallel.

Hereinafter, a configuration common to the charging unit 14a and the second charging unit 14b will be described. As shown in FIGS. 3 and 4, the first charging unit 14 a and the second charging unit 14 b are electrically connected to the power generation unit 12 by being attached to the power generation unit 12. At this time, the rectifier circuit 64 is connected to the generator 34 via the parallel connection circuit 62a, and the controller 78 is connected to the servo motor 52 and the ignition unit 48. The overcharge monitoring circuit 80 is also connected to the ignition unit 48.

The three-phase AC power generated by the generator 34 is input to the rectifier circuit 64 via the parallel connection circuit 62a or the series connection circuit 62b. The rectifier circuit 64 converts the three-phase AC power generated by the generator 34 into DC power. The rectifier circuit 64 is electrically connected to the positive output terminal 72 and the negative output terminal 74. The DC power from the rectifier circuit 64 is supplied as charging power from the positive output terminal 72 and the negative output terminal 74 to the first battery pack 18a or the second battery pack 18b.

The cutoff switch 68 is provided on a circuit connecting the rectifier circuit 64 and the positive output terminal 72. When the cutoff switch 68 is turned on, the rectifier circuit 64 and the positive electrode output terminal 72 are electrically connected. When the cutoff switch 68 is turned off, the rectifier circuit 64 and the positive electrode output terminal 72 are electrically cut off. As an example, the cutoff switch 68 of the present embodiment is a semiconductor switch, and more specifically, a field effect transistor (FET). Alternatively, the cutoff switch 68 may be a switch having a contact point that makes physical contact, such as a relay. The cutoff switch 68 is controlled by the controller 78.

The current detection circuit 70 is provided on a circuit that connects the rectifier circuit 64 and the negative output terminal 74, and detects the charging current of the battery packs 18a and 18b. Although an example, the current detection circuit 70 of this embodiment is a shunt resistor and outputs a voltage signal corresponding to the magnitude of the charging current. A value detected by the current detection circuit 70 is input to the controller 78.

The controller 78 is mainly configured using a microprocessor. The controller 78 controls the overall operation of the charger 10 including the power generation unit 12. The controller 78 controls the servo motor 52 based on the detected value of the charging current by the current detection circuit 70, thereby adjusting the output of the engine 38. As an example, the controller 78 stores a target value of the charging current. When the detected value of the charging current is smaller than the target value, the output of the engine 38 is increased and the detected value is larger than the target value. In some cases, the output of the engine 38 is reduced. Thereby, the output of the engine 38 is adjusted so that the charging current is maintained at the target value. By directly adjusting the output of the engine 38, a circuit such as a switching power supply becomes unnecessary, and unnecessary fuel consumption is suppressed. Note that the controller 78 preferably adjusts the output of the engine 38 based on other indicators indicating the state of the battery packs 18a and 18b such as the charging voltage and temperature instead of the charging current.

The controller 78 can detect the charging voltage of the battery packs 18a and 18b by monitoring the voltage of the positive output terminal 72. The controller 78 stores the upper limit value of the charging voltage, and determines that the battery packs 18a and 18b are fully charged or overcharged when the detected charging voltage exceeds the upper limit value. In this case, the controller 78 outputs a predetermined signal (engine stop signal) to the ignition unit 48 to stop the engine 38. Thereby, overcharging of the battery packs 18a and 18b is prevented. In addition, the controller 78 turns off the cutoff switch 68 and electrically disconnects the battery packs 18 a and 18 b from the generator 34.

In addition, the controller 78 stores an upper limit value of the charging current, and when the detected value of the charging current by the current detection circuit 70 exceeds the upper limit value, an abnormality occurs in the servo motor 52 or other components. The engine stop signal is output to the ignition unit 48. As a result, the engine 38 is stopped and charging of the battery packs 18a and 18b is stopped. In addition, the controller 78 turns off the cutoff switch 68 and electrically disconnects the battery packs 18 a and 18 b from the generator 34. Thereby, an excessive current flows through the battery packs 18a and 18b, and the battery packs 18a and 18b are prevented from being damaged.

The controller 78 is connected to the communication terminal 76 and is connected to be communicable with the battery controller 22 of the battery packs 18a and 18b. The battery controller 22 monitors the charging voltage (that is, the voltage of the battery cell 20) in the battery packs 18a, 18b, and the battery controller 22 detects the battery voltage when the detected charging voltage exceeds a predetermined value. It is determined that the

packs

18a and 18b are fully charged or overcharged, and a charge stop signal is output. When the controller 78 of the charger 10 receives the charge stop signal from the battery packs 18 a and 18 b, the controller 78 outputs the engine stop signal to the ignition unit 48 to stop the engine 38. Thereby, overcharging of the battery packs 18a and 18b is prevented. In addition, the controller 78 turns off the cutoff switch 68 and electrically disconnects the battery packs 18 a and 18 b from the generator 34.

In the charger 10 according to the present embodiment, not only the charging voltage detected in the charger 10 but also the charging voltage of each or the plurality of battery cells 20 detected in the battery packs 18a and 18b exceeds the upper limit value. When the engine 38 is stopped, the charging can be terminated. Thereby, even when the charger 10 cannot correctly detect the charging voltage, overcharging of the battery packs 18a and 18b can be prevented.

The controller 78 can also control the servo motor 52 and / or the ignition unit 48 based on other signals output from the battery packs 18a and 18b. For example, the controller 78 can output the engine stop signal to the ignition unit 48 when the battery packs 18a and 18b receive a predetermined abnormality signal. For example, when the charging current or temperature of the battery packs 18a and 18b (that is, the battery cell 20) is out of a predetermined allowable range, the battery packs 18a and 18b can serve as output signals. Alternatively, when the controller 78 cannot receive a predetermined signal from the battery packs 18a and 18b, the controller 78 may determine that an abnormality has occurred in the battery packs 18a and 18b and output the engine stop signal.

In the charger 10 of this embodiment, an overcharge monitoring circuit 80 is further provided to prevent overcharging of the battery packs 18a and 18b. The overcharge monitoring circuit 80 is connected to the communication terminal 76 and can receive a charge stop signal output from the battery packs 18a and 18b. When receiving the charge stop signal from the battery packs 18a, 18b, the overcharge monitoring circuit 80 outputs the engine stop signal to the ignition unit 48 to stop the engine 38. Thereby, overcharging of the battery packs 18a and 18b is prevented. The overcharge monitoring circuit 80 can operate independently of the controller 78 because it includes a microprocessor different from the controller 78 described above or other integrated circuit that can detect a charge stop signal. Therefore, even if an error occurs in the controller 78, the overcharge monitoring circuit 80 prevents overcharge of the battery packs 18a and 18b. Similar to the controller 78, the overcharge monitoring circuit 80 may control (for example, stop) the ignition unit 48 based on other signals output from the battery packs 18a and 18b.

The charger 10 of the present embodiment can charge the first battery pack 18a having a nominal voltage of 18 volts by using the first charging unit 14a. Moreover, the 2nd battery pack 18b whose nominal voltage is 36 volts can be charged by using the 2nd charging unit 14b. Here, when the first charging unit 14a is used, the generator 34 can generate power of about 21 volts at the maximum, so that the nominal voltage such as 12 volts, 14.4 volts, 18 volts is 20 volts or less. The battery pack can also be charged. On the other hand, when the second charging unit 14b is used, the generator 34 can generate power of about 42 volts at the maximum, so 21.6 volts, 25.2 volts, 28.8 volts, 32.4 volts, etc. A battery pack having a nominal voltage of 40 volts or less can be charged.

The charger 10 of the present embodiment can fully charge the first battery pack 18a having a nominal voltage of 18 volts and a capacity of 3 amp hours within 15 minutes to 30 minutes from the state where the remaining capacity is zero. On the other hand, the second battery pack 18b having a nominal voltage of 36 volts and a capacity of 3 amp hours can be fully charged within 30 minutes or more and 60 from the state where the remaining capacity is zero.

With reference to FIG. 7, the charger 110 according to the second embodiment will be described. In the charger 110 according to the second embodiment, only the parallel connection circuit 62a and the series connection circuit 62b are provided so as to be interchangeable as compared with the charger 10 according to the first embodiment. Other configurations are the same as those in the first embodiment. About the structure which is common in Example 1, the description which overlaps here is abbreviate | omitted by attaching | subjecting the same code | symbol.

The charger 110 has a first charging unit 114a having a parallel connection circuit 62a and a second charging unit 114b having a series connection circuit 62b. The first charging unit 114 a and the second charging unit 114 b can be alternatively attached between the AC generator 34 and the rectifier circuit 64. When charging the first battery pack 18 a described in the first embodiment, the first charging unit 114 a having the parallel connection circuit 62 a is attached to the charger 110. At this time, the charger 110 has substantially the same configuration as the combination of the power generation unit 12 and the first charging unit 14a described in the first embodiment. On the other hand, when charging the second battery pack 18b described in the first embodiment, a second charging unit 114b having a series connection circuit 62b is attached to the charger 110 instead of the first charging unit 114a. At this time, the charger 110 has substantially the same configuration as the combination of the power generation unit 12 and the second charging unit 14b described in the first embodiment. The battery mounting portion 116 of the charger 110 can selectively attach / detach both the first battery pack 18a and the second battery pack 18b.

Also in the charger 110 of the present embodiment, the voltage generated by the generator 34 is changed according to the charging

units

114a and 114b to be used. Thereby, the battery packs 18a and 18b having different nominal voltages can be charged by the single generator 34 without requiring a circuit such as a switching power supply.

The charger 210 according to the third embodiment will be described with reference to FIG. 8, FIG. 9, and FIG. In the charger 210 according to the third embodiment, unlike the

chargers

10 and 110 according to the first and second embodiments, two circuits of a parallel connection circuit 62a and a series connection circuit 62b are configured by one connection switching circuit 262. Other configurations are the same as those in the first embodiment. About the structure which is common in Example 1, the description which overlaps here is abbreviate | omitted by attaching | subjecting the same code | symbol.

The connection switching circuit 262 is provided between the generator 34 and the rectifier circuit 64. As illustrated in FIGS. 9 and 10, the connection switching circuit 262 includes a plurality of switching

elements

271, 272, and 273. When charging the first battery pack 18a described in the first embodiment, the connection switching circuit 262 turns on the first switching element 271 and the third switching element 273 and turns off the second switching element 272. Thereby, the first coil group 92 and the second coil group 94 of the generator 34 are connected in parallel to each other. At this time, the charger 210 has substantially the same configuration as the combination of the power generation unit 12 and the first charging unit 14a described in the first embodiment. On the other hand, when charging the second battery pack 18b described in the first embodiment, the connection switching circuit 262 turns off the first switching element 271 and the third switching element 273 as shown in FIG. The switching element 272 is turned on. Thereby, the first coil group 92 and the second coil group 94 of the generator 34 are connected in series with each other. At this time, the charger 210 has substantially the same configuration as the combination of the power generation unit 12 and the second charging unit 14b described in the first embodiment. The battery mounting portion 216 of the charger 210 can selectively attach / detach both the first battery pack 18a and the second battery pack 18b.

In the charger 210 of the present embodiment, the voltage generated by the generator 34 can be changed by the connection switching circuit 262. Thereby, the battery packs 18a and 18b having different nominal voltages can be charged by the single generator 34 without requiring a circuit such as a switching power supply.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and achieving one of the objects itself has technical utility.

Claims

A charger for charging a battery pack of an electric device,
Engine,
A generator driven by the engine;
The battery pack is detachable, and a battery mounting portion that outputs power from the generator to the battery pack;
With a charger.
The charger according to claim 1, wherein the engine has a displacement of 25 milliliters or less.
The charger according to claim 1 or 2, wherein the engine has a displacement of 5 ml or more and 20 ml or less.
The generator is an AC generator;
The charger according to any one of claims 1 to 3, further comprising a rectifier circuit provided between the generator and the battery mounting portion.
5. The charging according to claim 1, further comprising: a cutoff switch that is provided between the generator and the battery mounting portion and cuts off power supply from the generator to the battery mounting portion. vessel.
The charger according to any one of claims 1 to 5, wherein a maximum generated voltage of the generator is 42 volts or less.
The battery pack having a nominal voltage of 18 volts and a capacity of 3 ampere hours is configured to be fully charged within 30 minutes to 30 minutes after the remaining capacity is zero. The charger described.
The charger according to any one of claims 1 to 7, wherein the engine can be started using an electric tool.