Electrical equipment

Abstract

To provide electrical equipment with improved convenience.SOLUTION: In an air compressor 1, when the temperature of a battery pack 5 exceeds a discharge prohibition threshold, power supply from the battery pack 5 to a motor 14 is prohibited, and when the temperature of the battery pack 5 exceeds a predetermined charge prohibition threshold, power supply from a charging unit 70 to the battery pack 5 is prohibited. In the air compressor 1, it is possible to switch between a mode in which the discharge prohibition threshold is equal to or less than the charge prohibition threshold and a mode in which the discharge prohibition threshold is higher than the charge prohibition threshold.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to electrical equipment such as air compressors.

Background Art

[0002] In an air compressor, which is an example of electrical equipment, a motor is provided as an example of a load. The driving force of the motor drives a piston to discharge compressed air from a cylinder and store it in a tank. The compressed air stored in the tank is supplied to air tools. In the configuration of Patent Document 1, a battery pack is detachably attached to a main body provided with a load portion and a charging portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a secondary battery provided in a battery pack, there are temperature ranges that are not preferable for discharge and charge, respectively. Therefore, a discharge prohibition threshold value and a charge prohibition threshold value are provided for the temperature of the secondary battery. Since discharge can be carried out at a higher temperature than charge, for the purpose of ensuring a long discharge time, it is common for the discharge prohibition threshold value to be set higher than the charge prohibition threshold value.

[0005] In the case of a configuration in which both a load portion and a charging portion are provided in the main body as in Patent Document 1, when the temperature exceeds the discharge prohibition threshold value and discharge is stopped, it is desirable that charging starts immediately in preparation for the next discharge. On the other hand, if the discharge prohibition threshold value is set higher than the charge prohibition threshold value, the temperature of the secondary battery after discharge stop is higher than the charge prohibition threshold value. Therefore, it was necessary to wait for a long time until the temperature decreased and fell below the charge prohibition threshold value. For this reason, charging could not be efficiently performed on the secondary battery, and convenience was impaired.

[0006] In view of the above problems, an object of the present invention is to provide an electrical device with improved convenience.

Means for Solving the Problems

[0007] One aspect of the present invention is an electrical device. This electrical device includes a load unit that receives power and performs work, a battery unit having a secondary battery and capable of supplying power to the load unit, a charging unit connected to a commercial power supply and capable of charging the secondary battery by supplying power to the battery unit, a temperature detection unit that detects the temperature of the battery unit, and a control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detection value of the temperature detection unit. When the detection value of the temperature detection unit exceeds a predetermined discharge prohibition threshold value, the control unit prohibits the power supply from the battery unit to the load unit, and when the detection value of the temperature detection unit exceeds a predetermined charge prohibition threshold value, the control unit prohibits the power supply from the charging unit to the battery unit. The discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value. , an electrical equipment main body having the load unit and the charging unit; a battery pack detachably attached to the electrical equipment main body, the battery pack having the battery unit and the temperature detection unit; the control unit: when power is supplied from the battery unit to the load unit, prohibits power supply from the charging unit to the battery unit; when power is not supplied from the battery unit to the load unit, and the detected value of the temperature detection unit does not exceed the charge prohibition threshold value, permits power supply from the charging unit to the battery unit 。 Another aspect of the present invention is an electrical equipment. This electrical equipment has a load unit that receives power and performs work; has a secondary battery and a battery unit capable of supplying power to the load unit; is connected to a commercial power supply and has a charging unit capable of charging the secondary battery by supplying power to the battery unit; has a temperature detection unit that detects the temperature of the battery unit; has a control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detected value of the temperature detection unit; when the detected value of the temperature detection unit exceeds a predetermined discharge prohibition threshold value, the control unit prohibits power supply from the battery unit to the load unit, and when the detected value of the temperature detection unit exceeds a predetermined charge prohibition threshold value, the control unit prohibits power supply from the charging unit to the battery unit; the discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value; an electrical equipment main body having the load unit; a first battery pack detachably attached to the electrical equipment main body, the first battery pack having the battery unit and the temperature detection unit; a second battery pack detachably attached to the electrical equipment main body, the second battery pack having the battery unit and the temperature detection unit; when power is supplied from the battery unit of the first battery pack to the load unit, if the detected value of the temperature detection unit of the first battery pack exceeds the discharge prohibition threshold value, the control unit prohibits power supply from the battery unit of the first battery pack to the load unit and permits power supply from the battery unit of the second battery pack to the load unit. Another aspect of the present invention is an electrical equipment. This electrical equipment has a load unit that receives power and performs work; has a secondary battery and a battery unit capable of supplying power to the load unit; is connected to a commercial power supply and has a charging unit capable of charging the secondary battery by supplying power to the battery unit; has a temperature detection unit that detects the temperature of the battery unit; A control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detection value of the temperature detection unit; When the detection value of the temperature detection unit exceeds a predetermined discharge prohibition threshold, the control unit prohibits the power supply from the battery unit to the load unit, and when the detection value of the temperature detection unit exceeds a predetermined charge prohibition threshold, the control unit prohibits the power supply from the charging unit to the battery unit. The discharge prohibition threshold is equal to or lower than the charge prohibition threshold. It is possible to switch between a mode in which the discharge prohibition threshold is equal to or lower than the charge prohibition threshold and a mode in which the discharge prohibition threshold is higher than the charge prohibition threshold.

[0008] In addition, any combination of the above components, or a conversion of the expression of the present invention between methods, systems, etc., is also effective as an aspect of the present invention.

Advantages of the Invention

[0009] According to the present invention, an electric device with improved convenience can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0011] In the following, the same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and redundant explanations are omitted as appropriate. The embodiments are illustrative and not restrictive of the invention. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0012] (Embodiment 1) Hereinafter, an air compressor 1 which is an embodiment of an electric device will be described in detail with reference to the drawings. The air compressor 1 operates on a commercial AC power supply (AC power 100V) and has a power cord 2 and a plug (not shown) for connecting to a commercial power outlet. The air compressor 1 can perform an assist operation using a battery power supply. As shown in FIG. 4, a plurality (two in the illustrated case) of battery pack mounting portions 45 are provided on the outer surface of the main body cover (housing) 10.

[0013] A battery pack 5 as a battery unit can be detachably mounted on each of the battery pack mounting portions 45. FIG. 4 shows a state where the battery pack 5 is mounted on one battery pack mounting portion 45. However, the battery pack 5 can be mounted on each battery pack mounting portion 45, and a total of two battery packs 5 can be used for assistance. The battery pack 5 has a housing case and a secondary battery (secondary battery cell) provided in the housing case. The battery pack mounting portion 45 has a connection terminal for connecting to the terminal of the battery pack 5.

[0014] The air compressor 1 includes a main body cover 10, carrying handles 11 provided on both sides of the main body cover 10, a pair of air tanks 12a and 12b arranged in parallel for storing compressed air, a compression unit 13 (FIG. 3) for compressing air inhaled from the outside and supplying it to the air tanks 12a and 12b, and a motor 14 (same) connected to the compression unit 13 and driving the compression unit 13. The motor 14 is an example of a load unit.

[0015] The compression unit 13 and the motor 14 are arranged above the pair of air tanks 12a and 12b such that the axial direction of the motor 14 is substantially orthogonal to the longitudinal direction of the air tanks 12a and 12b. Legs 15 are provided on the air tanks 12a and 12b to prevent direct contact with the ground and protect them. The motor 14 is, for example, a DC brushless motor. By controlling (e.g., PWM control) the inverter unit 33 in FIGS. 5A and 5B that supplies power to the motor 14 by the main control unit 40 (including a control circuit such as a CPU), the rotation speed etc. of the motor 14 are controlled.

[0016] The user can perform operations such as turning the power of the air compressor 1 on and off (ON·OFF), starting and stopping the motor 14, and switching the operation mode by the operation panel unit (switch panel) 19. Warnings such as the internal pressure of the air tank and overload are displayed on the operation panel unit 19.

[0017] The compression unit 13 is composed of a first-stage low-pressure compression unit 17 and a second-stage high-pressure compression unit 18. The first-stage low-pressure compression unit 17 and the second-stage high-pressure compression unit 18 are arranged to face each other via the crankcase 16. The first-stage low-pressure compression unit 17 compresses the external air (atmospheric pressure) sucked in through the inside of the crankcase 16 and sends the compressed air to the second-stage high-pressure compression unit 18 via the first-stage discharge pipe. The second-stage high-pressure compression unit 18 compresses the compressed air supplied from the first-stage low-pressure compression unit 17 to an allowable maximum pressure of, for example, 3.0 to 4.5 MPa and supplies it to the air tanks 12a and 12b that communicate with each other via the second-stage discharge pipe.

[0018] The compressed air in the air tanks 12a and 12b is decompressed by the pressure reducing valves 24a and 24b and taken out to the outside via the couplers 27a and 27b. The pressure in the vicinity of the couplers 27a and 27b can be monitored by the pressure gauges 26a and 26b. An air tool such as a nail gun is connected to each of the couplers 27a and 27b via a hose (not shown).

[0019] The pressures on the output sides of the pressure reducing valves 24a and 24b (the supply pressures to the air tools) can be adjusted by the pressure adjusting members 23a and 23b. By the pressure reducing valves 24a and 24b, regardless of the magnitudes of the pressures on the inlet sides of the compressed air to the air tanks 12a and 12b, the pressures on the coupler 27a and 27b sides can be suppressed to a constant value not exceeding the maximum pressure. That is, the couplers 27a and 27b can obtain compressed air having a constant pressure regardless of the pressures in the air tanks 12a and 12b. Note that a drain discharging device is provided to discharge the drain and the compressed air accumulated inside the air tanks 12a and 12b to the outside.

[0020] As shown in FIG. 5A, the air compressor 1 has a motor 14 for rotationally driving the compression unit 13 to send compressed air into the air tanks 12a and 12b. The air compressor 1 includes a main body circuit unit 200 for driving the motor 14 using a commercial AC power supply 39 which is an external AC power supply, and an auxiliary circuit unit 300 for power assist using two battery packs 5-A and 5-B.

[0021] As shown in FIGS. 5A and 5B, the main body circuit unit 200 includes a rectifying unit 31, an AC side power supply boosting circuit 32, an inverter unit 33, and a main control unit 40 for controlling the inverter unit 33 in order to drive the motor 14 by receiving the supply of a commercial AC power supply 39 (AC100V: for example, the maximum rated current of an outlet is 15A) which is an external AC power supply.

[0022] A noise filter 34 is inserted between the commercial AC power supply 39 and the rectifying unit 31. A smoothing capacitor 35 is connected to the rectified output side of the rectifying unit 31. The AC power from the AC power supply 39 is rectified by the rectifying unit 31, and the DC power smoothed by the smoothing capacitor 35 is supplied to the AC side power supply boosting circuit 32. A current detection resistor 36 is inserted into the connection line between the rectifying unit 31 and the AC side power supply boosting circuit 32. The AC side load current detection unit 37 detects (monitors) the AC load current based on the voltage drop across both ends of the current detection resistor 36, and outputs an AC load current detection signal to the main control unit 40.

[0023] The AC-side power supply boost circuit 32 includes a boost circuit such as a DC-DC converter, and the DC power boosted here is supplied to the motor 14 via the inverter section 33. The rectifier section 31, the AC-side power supply boost circuit 32, and the smoothing capacitor 35 are an example of an AC-side power supply section.

[0024] In the illustrated case, the AC-side power supply boost circuit 32 is a chopper-type DC-DC converter having a choke coil 321, a switching element 322, a diode 323, and a capacitor 324, and has a boost voltage control section 325 that controls the switching operation of the switching element 322. A boost voltage detection section 38 is provided on the boost output side of the AC-side power supply boost circuit 32.

[0025] The main control section 40 receives the boost voltage monitoring signal from the boost voltage detection section 38, the rotation detection signal from the rotation sensor 41 that detects the rotation of the motor 14, and the pressure detection signal from the pressure sensor 42 that detects the pressures of the air tanks 12a and 12b. The main control section 40 outputs a boost voltage control signal to the AC-side power supply boost circuit 32 (boost voltage control section 325), outputs an inverter control signal to the inverter section 33, and supplies the DC power boosted by the AC-side power supply boost circuit 32 to the motor 14 via the inverter section 33, thereby controlling the rotation of the motor 14 by, for example, PWM control. The compression section 13 is rotationally driven by the motor 14, and the air discharged from the compression section 13 is sent to the air tanks 12a and 12b.

[0026] The operation panel section 19 has a display panel 191 that displays warnings such as the pressures inside the air tanks 12a and 12b and overload, an operation button 192 for switching the power on and off, a charging button 193 for instructing the charging of the battery packs 5-A and 5-B, a mode switching button 194 for instructing the switching of the operation mode, and an assist button 195 for instructing the power assist using the battery packs 5-A and 5-B, and a switch panel control section 190 is provided to control these. The switch panel control section 190 is connected to the main control section 40 via the communication circuit 197.

[0027] In order to supply a stabilized DC voltage to the main control unit 40, the operation panel unit 19, the communication circuit 197, etc., a circuit power supply unit 90 is provided. The circuit power supply unit 90 uses the DC output of the rectification unit 31 to supply the power supply voltage Vcc(A) to the main control unit 40, etc., and the power supply voltage Vcc(C) to the switch panel control unit 190, the communication circuit 197, etc. respectively. The circuit power supply unit 90 includes a step-down transformer 91 having one primary winding and two secondary windings, a switching element 92 for switching the primary side of the transformer, a circuit power supply drive circuit 93 for outputting a drive signal to the switching element 92, and rectifying and smoothing circuits 94 and 95 provided in the two secondary windings respectively. The DC output voltage of the rectifying and smoothing circuit 94 is supplied to the main control unit 40, etc. as Vcc(A), and the DC output voltage of the rectifying and smoothing circuit 95 is supplied to the switch panel control unit 190, the communication circuit 197, etc. as Vcc(C).

[0028] As shown in FIGS. 5A, 5C, and 5D, the auxiliary circuit unit 300 includes an assist power supply unit 50 for performing drive assistance for the motor 14 with a battery power supply (DC power supply), a charging unit 70 for charging the battery packs 5-A and 5-B as the battery power supply, a sub-control unit 80, a circuit power supply unit 110, and a communication circuit 100. The sub-control unit 80 is configured to include a control circuit such as a CPU, and controls the operations of the assist power supply unit 50 and the charging unit 70 in cooperation with the main control unit 40. The circuit power supply unit 110 supplies a stabilized DC voltage to the sub-control unit 80, the communication circuit 100, etc. The communication circuit 100 constitutes an electrically insulated communication line between the main control unit 40 and the sub-control unit 80. The auxiliary circuit unit 300 is housed, for example, in the storage case unit 20 inside the main body cover 10 of FIG. 3.

[0029] The battery pack 5-A is connected to the connection terminal 45A of one battery pack mounting portion 45, and the battery pack 5-B is connected to the connection terminal 45B of the other battery pack mounting portion 45. Battery voltage detection units 46A and 46B are respectively provided to detect the battery pack voltages of the battery packs 5-A and 5-B connected to the connection terminals 45A and 45B. The battery voltage detection signals from the respective battery voltage detection units 46A and 46B are supplied to the sub-control unit 80. The sub-control unit 80 receives battery information acquisition signals from the battery packs 5-A and 5-B and acquires their battery information (such as battery temperature). The battery packs 5-A and 5-B respectively include control units 44A and 44B and can communicate with the sub-control unit 80. The main control unit 40, the sub-control unit 80, and the control units 44A and 44B of the battery packs 5-A and 5-B constitute the control unit of the air compressor 1.

[0030] The assist power supply unit 50 includes a configuration of a step-up DC-DC converter as a step-up circuit. The assist power supply unit 50 has switching elements (for example, MOSFETs) 52 and 53 push-pull connected to the primary side of the step-up transformer 51, an assist power supply drive circuit 54 that switches the switching elements 52 and 53 alternately, a rectifying unit 55 connected to the secondary side of the step-up transformer 51, a choke coil 63, a smoothing capacitor 56, and an assist current control unit 57.

[0031] A current detection resistor 58 is inserted into the connection line between the rectifier section 55 and the inverter section 33. The assist current control section 57 detects (monitors) the assist current from the voltage drop across both ends of the current detection resistor 58, and feeds back an assist current detection signal to the assist power supply drive circuit 54 via a photocoupler 59 as a feedback circuit. Here, the reason for using the photocoupler 59 is to electrically insulate the main body circuit section 200 electrically connected to the AC power supply 39 and the auxiliary circuit section 300 electrically connected to the battery packs 5-A and 5-B from each other. The same reason applies to the use of the photocoupler in the following description. The boost transformer 51 is an example of a boost circuit. The connection terminal 45A to which the battery pack 5-A is connected, the battery voltage detection section 46A, the charging section 70, the connection terminal 45B to which the battery pack 5-B is connected, the battery voltage detection section 46B, the charging section 70, and the assist power supply section 50 are an example of a battery-side power supply section capable of adjusting the output voltage values of the battery pack 5-A and the battery pack 5-B.

[0032] The DC power of one or both of the battery packs 5-A and 5-B is supplied to the primary side of the boost transformer 51 of the assist power supply section 50. An assist voltage detection section 60 for detecting the output voltage of the assist power supply section 50 is provided on the output side of the rectifier section 55 of the assist power supply section 50, and an assist voltage control section 61 is provided for controlling the output voltage of the assist power supply section 50. The DC output power of the assist power supply section 50 is supplied to the inverter section 33 via a series diode 82 (combined with the DC output power of the AC side power supply boost circuit 32).

[0033] The sub-control section 80 outputs an output current control signal to the assist current control section 57 of the assist power supply section 50 via a photocoupler 62, and outputs an output voltage control signal of the assist power supply 50 to the assist voltage control section 61 via a photocoupler 64.

[0034] The output terminal of the assist power supply section 50 is connected in parallel to the output terminal of the AC side power supply boost circuit 32 via a series diode 82. That is, the AC side power supply boost circuit 32 and the assist power supply section 50 are electrically connected in parallel to the motor 14.

[0035] Specifically, in the assist power supply unit 50, in response to the output current control signal and the output voltage control signal from the sub-control unit 80, the drive signal of the assist power supply drive circuit 54 is controlled, and by changing the duty when alternately switching the switching elements 52 and 53, voltage variable control for increasing or decreasing the DC voltage across the smoothing capacitor 56 on the output side can be performed. In other words, the assist power supply unit 50 can drive the motor 14 by PAM control for increasing or decreasing the supply voltage to the inverter 33 unit. Further, an assist power supply on / off signal is supplied from the sub-control unit 80 to the assist power supply drive circuit 54 of the assist power supply unit 50. When the assist power supply on / off signal instructs "assist power supply on", the assist power supply drive circuit 54 is operated to enable switching, and when it instructs "assist power supply off", the operation of the assist power supply drive circuit 54 is stopped.

[0036] The charging unit 70 is a circuit for charging the battery packs 5-A and 5-B mounted on the battery pack mounting unit 45. The charging unit 70 includes a configuration of a step-down DC-DC converter. The charging unit 70 includes a rectifying unit 71 that receives the supply of the AC power supply 39 via the noise filter 35, a smoothing capacitor 72, a step-down transformer 73, a switching element 74 that switches the primary side of the transformer, a charging power supply drive circuit 75 that on / off drives the switching element 74, a diode 76 and a smoothing capacitor 77 as a rectifying and smoothing circuit for rectifying and smoothing the secondary side output of the transformer 73, a charging current control unit 78, and a charging voltage control unit 79. A current detection resistor 81 is inserted into the connection line between the rectifying and smoothing circuit on the secondary side of the transformer 73 and the battery packs 5-A and 5-B. The charging current control unit 78 detects (monitors) the charging current from the voltage drop across both ends of the current detection resistor 81. The charging current detection signal from the charging current control unit 78 and the charging voltage control signal from the charging voltage control unit 79 are fed back to the charging power supply drive circuit 75 via a photocoupler 82 as a feedback circuit.

[0037] The circuit power supply unit 110 supplies the power supply voltage Vcc(B) to the sub-control unit 80 and the like, and supplies power to the photocoupler 85 that transmits the charging power on / off signal, by using the DC output of the rectifying unit 71 of the charging unit 70. The circuit power supply unit 110 includes a step-down transformer 111 having one primary winding and two secondary windings, a switching element 112 that switches the primary side of the transformer, a circuit power supply drive circuit 113 that outputs a drive signal to the switching element 112, and rectifying and smoothing circuits 114 and 115 provided in the two secondary windings respectively. The DC output voltage of the rectifying and smoothing circuit 114 is supplied as Vcc(B) to the sub-control unit 80, the photocoupler 82, etc. The DC output voltage of the rectifying and smoothing circuit 115 is supplied to the photocoupler 85. The photocoupler 85 transmits the charging power on / off signal of the sub-control unit 80 to the charging power drive circuit 75. When the charging power on / off signal indicates "charging power on", the charging power drive circuit 75 is activated to switch the switching element 74, and when it indicates "charging power off", the operation of the charging power drive circuit 75 is stopped.

[0038] A relay 87A (first cutoff circuit) is provided to turn on and off the connection between the connection terminal 45A of one battery pack mounting portion 45 and the charging unit 70, and a relay 87B (second cutoff circuit) is provided to turn on and off the connection between the connection terminal 45B of the other battery pack mounting portion 45 and the charging unit 70. Also, a relay 87C is provided to turn on and off the connection between the connection terminal 45A and the assist power supply unit 50, and a relay 87D is provided to turn on and off the connection between the connection terminal 45B and the assist power supply unit 50. The relays 87A to 87D are each on / off controlled by a relay on / off signal from the sub-control unit 80.

[0039] The communication circuit 100 has two photocouplers 101 and 102, and constitutes an electrically insulated communication line between the main control unit 40 and the sub-control unit 80. The photocoupler 101 transmits the information signal from the main control unit 40 to the sub-control unit 80, and the photocoupler 102 transmits the information signal from the sub-control unit 80 to the main control unit 40.

[0040] In the battery packs 5-A and 5-B, thermistors Th1 and Th2 are respectively provided as temperature detection units for detecting the temperature of the internal secondary battery. Also, a thermistor Th3 for temperature detection is provided for the switching elements 52 and 53 of the assist power supply unit 50. The temperature monitoring signals of the thermistors Th1 to Th3 are output to the sub-control unit 80, and the battery packs 5 and the assist power supply unit 50 whose temperature rise exceeds the allowable range are stopped from operating by the sub-control unit 80.

[0041] In the operation panel unit 19 of FIG. 5B, the display panel 191 is a display unit for displaying various information from the main control unit 40. The operation button 192 is a switch for instructing the start and stop of the operation of the air compressor 1. The charging button 193 is a switch for instructing the permission and stop of charging of the battery packs 5-A and 5-B. The mode switching button 194 is a switching switch for switching the operation mode of the air compressor 1 described later. The assist button 195 is a switching switch for switching between a mode in which power assist using the battery pack is used in combination and a mode in which power assist is not used.

[0042] In the circuit configuration of FIGS. 5A to 5D, the air compressor 1 is used in a state of being connected to a commercial AC power supply 39 (AC100V). Since the main body circuit unit 200 receives power supply from the commercial AC power supply 39, it is controlled by the main control unit 40 based on the value of the AC side load current detection unit 37 so that the input current from the commercial AC power supply 39 becomes 15 A or less. This is because the maximum rated current of a general AC outlet is 15 A.

[0043] During normal operation, when the AC load current value is about to exceed 15 A, the main control unit 40 decreases the target rotational speed of the motor 14. The target rotational speed also changes depending on the load of the inverter unit 33 and the pressures in the air tanks 12a and 12b. Specifically, it is set high in the case of a light load, and low when the pressure in the tank increases or when the amount of compressed air used is large.

[0044] During power assist operation to activate the assist power supply unit 50, when the target rotational speed is reached, the AC current value decreases. Therefore, the main control unit 40 increases the target rotational speed to maintain the AC load current value at 15 A, enabling the insufficient power to be supplied from one or both of the battery packs 5-A and 5-B. At this time, the sub-control unit 80 can keep the rotational speed of the motor 14 within a certain range by imposing restrictions on the supply current or supply power from the battery pack 5.

[0045] Here, pay attention to the following points. The AC-side power supply boost circuit 32 performs feedback control so that the boosted voltage reaches the target value. However, when the series diode 323A is not inserted, especially when the assist voltage from the assist power supply unit 50 is too high, the control will lower the boosted voltage. When the boosted voltage decreases, the current supply from the commercial AC power supply 39 decreases, resulting in an excessive current supply from the battery pack 5 and ultimately leading to a reduction in the power assist time. In this case, if the assist voltage (output voltage of the assist power supply unit 50) is controlled to be higher by about the forward voltage drop (1V - 2V) of the series diode 82, the series diode 323A can be omitted.

[0046] On the other hand, when the series diode 323A is inserted, it is necessary to provide a voltage merging section electrolytic capacitor 324A at the location where the boosted voltage and the assist voltage are connected. This is to absorb the surge energy generated when the motor 14 stops, and a large-capacity and high-voltage-resistant large component is used. However, when the series diode 323A is omitted as described above, it can be substituted by the electrolytic capacitor 324 of the AC-side power supply boost circuit 32, so the voltage merging section electrolytic capacitor can also be omitted. This can not only reduce the area on the substrate and the cost of electronic components, but also improve the efficiency reduction due to diode losses and voltage drops.

[0047] Generally, when a plurality of battery packs are connected in parallel, in order to prevent reverse current between the battery packs, the reverse current prevention diodes 47A and 47B shown by the dotted line in Fig. 5C are required. However, by charging the battery packs alternately so that the potential difference between the battery packs 5-A and 5-B is within a predetermined potential difference value (for example, 0.5V), in practice, the reverse current between the battery packs can be suppressed to the level of the charging current. Therefore, the diodes 47A and 47B may be deleted. As a result, the problems of output reduction due to the resistance of the diodes 47A and 47B and heat generation by the diodes 47A and 47B can be solved.

[0048] Even when the potential difference between the battery packs 5-A and 5-B exceeds the predetermined potential difference value (0.5V) and opens during power assist in which the battery packs 5-A and 5-B are connected in parallel, the assist is continued until the voltage of one of the battery packs falls below a predetermined voltage value V1 which is the first threshold voltage.

[0049] If an attempt is made to stop the assist for only one of the battery packs 5 during the power assist period, the discharge current of the other battery pack 5 will become excessive simultaneously with the stop. Therefore, it is necessary to reduce the current value, such as by lowering the target rotational speed of the motor 14. To actually stop, it is necessary to turn off the relay 87C or 87D during energization. From the viewpoint of suppressing contact failure, it is advisable to stop the assist itself when the voltage of one of the battery packs falls below the predetermined voltage value V1. The reason for this is that if the assist is continued until the voltages of both battery packs fall below the predetermined voltage value V1, the consumption current of the battery pack 5 that has dropped first will increase, accelerating voltage drop and heat generation, and thus delaying the cycle of recharge and re-assist.

[0050] Referring to FIGS. 6 to 10, charge and discharge control according to the temperature of the battery packs 5-A and 5-B will be described. In the air compressor 1, by operating the mode switching button 194, as the operation mode, a first mode in which the discharge prohibition threshold of the battery packs 5-A and 5-B is higher than the charge prohibition threshold and a second mode in which the discharge prohibition threshold is less than or equal to the charge prohibition threshold can be selected. Note that the discharge prohibition threshold being less than or equal to the charge prohibition threshold includes both the case where the discharge prohibition threshold is equal to the charge prohibition threshold and the case where the discharge prohibition threshold is lower than the charge prohibition threshold. In the examples of FIGS. 6 to 9, in the first mode, the discharge prohibition threshold is T1 and the charge prohibition threshold is T2 (T1>T2). In the second mode, both the discharge prohibition threshold and the charge prohibition threshold are T2. That is, the discharge prohibition threshold and the charge prohibition threshold are equal. In any mode, when discharging from the battery packs 5-A and 5-B (power supply from the battery packs 5-A and 5-B to the motor 14) is being performed, charging of the battery packs 5-A and 5-B (power supply from the charging unit 70 to the battery pack 5-A and / or 5-B) is prohibited.

[0051] FIG. 7 is a time chart showing the operation of the air compressor 1 in the first mode. In the first mode, after the discharge from the battery packs 5-A and 5-B starts at time t11, the temperature of the battery packs 5-A and 5-B rises. Even when the battery temperature exceeds T2 at time t12, the discharge is not stopped (prohibited). When the battery temperature exceeds T1 at time t13, the discharge is stopped (prohibited). When the discharge is stopped, the battery temperature starts to decline. When the battery temperature falls below T2 at time t14, charging becomes possible. Charging is prohibited when the battery temperature is T2 or higher, as in the period from time t13 to time t14. FIG. 8 is a time chart showing the operation of the air compressor 1 in the second mode. In the second mode, after the discharge from the battery packs 5-A and 5-B starts at time t21, the temperature of the battery packs 5-A and 5-B rises. When the battery temperature exceeds T2 at time t22, the discharge is stopped. Note that, due to the driving frequency of the sub-control unit 80, there is a very short time lag between the time when the battery temperature exceeds T2 and the time when the discharge is stopped. Therefore, the battery temperature at the time when the discharge is stopped slightly exceeds T2. When the discharge is stopped, the battery temperature starts to decline. When the battery temperature falls below T2 at time t23, charging becomes possible. The higher the driving frequency of the sub-control unit 80, the shorter the time lag from the time when the battery temperature exceeds T2 to the time when the discharge is stopped. Substantially, time t22 and time t23 can be made simultaneous and t2 can be set to zero. Note that, even if the temperature of either one of the battery packs 5-A and 5-B exceeds T2 and the temperature of the other does not exceed T2, only the battery pack with the temperature exceeding T2 may stop discharging, and the other battery pack with the temperature not exceeding T2 may continue discharging. Alternatively, even if the temperature of either one of the battery packs 5-A and 5-B exceeds T2 and the temperature of the other does not exceed T2, the discharge of both battery packs may be stopped.

[0052] In the first mode, compared with the second mode, the dischargeable time is longer by the amount that the discharge prohibition threshold is higher. However, after the battery temperature exceeds the discharge prohibition threshold and discharge stops, the time (t1 in FIG. 7) until the battery temperature becomes equal to or lower than T2 and charging can start is also long. In the second mode, compared with the first mode, although the dischargeable time is shorter by the amount that the discharge prohibition threshold is lower, after the battery temperature exceeds the discharge prohibition threshold and discharge stops, the time (t2 in FIG. 8) until the battery temperature becomes equal to or lower than T2 and charging can start is also short (t2 < t1). As shown in FIG. 10, in the second mode, the discharge prohibition threshold may be set to T3 (T3 < T2). At this time, the discharge prohibition threshold is lower than the charge threshold. In the time chart of FIG. 10, after discharge starts from battery packs 5-A and 5-B at time t31, the temperature of battery packs 5-A and 5-B rises, and when the battery temperature exceeds T3 at time t32, discharge stops. Since the temperature of battery packs 5-A and 5-B is lower than T2 at time t32, battery packs 5-A and 5-B start charging simultaneously when discharge stops at time t32. By setting the discharge prohibition threshold lower than the charge prohibition threshold in this way, charging becomes possible immediately after the battery temperature exceeds the discharge prohibition threshold and discharge stops.

[0053] FIG. 9 is a flowchart of charge and discharge control of battery packs 5-A and 5-B. The operator selects an operation mode by operating the mode change button 194 (S1). The sub-control unit 80 starts power assist and starts discharging from battery packs 5-A and 5-B (S2). Discharge here may be from only one of battery packs 5-A and 5-B.

[0054] When the operation mode selected in S1 is the first mode (Yes in S3), the sub-control unit 80 continues discharging until at least one of the temperatures of battery packs 5-A and 5-B exceeds T1 (No in S4), and when at least one of the temperatures of battery packs 5-A and 5-B exceeds T1 (Yes in S4), it stops discharging from battery packs 5-A and 5-B (S6).

[0055] When the operation mode selected in S1 is the second mode (No in S3), the sub-control unit 80 continues discharging until the temperature of at least one of the battery packs 5-A and 5-B exceeds T2 (No in S5). When the temperature of at least one of the battery packs 5-A and 5-B exceeds T2 (Yes in S5), the sub-control unit 80 stops discharging from the battery packs 5-A and 5-B (S6).

[0056] When the temperature of the battery packs 5-A and 5-B is not lower than T2 (No in S7), the sub-control unit 80 enters a charging standby state (S8). When the temperature of the battery packs 5-A and 5-B is lower than T2 (Yes in S7), the sub-control unit 80 starts charging the battery pack whose temperature has dropped below T2 (S9). During charging, power is supplied from the commercial AC power supply 39 to the battery packs 5-A and 5-B. However, control is performed so that the sum of the charging current and the supply current from the commercial AC power supply 39 to the motor 14 is equal to or less than the maximum rated current of the outlet (for example, 15 A). If the supply current to the motor 14 is insufficient and the rotational speed of the motor 14 decreases, which may hinder the driving of the compression unit 13, it is possible to wait for the start of charging, or to stop the driving of the motor 14 in accordance with the start of charging in S9.

[0057] According to the present embodiment, since it has the second mode in which the discharge prohibition threshold of the battery packs 5-A and 5-B is equal to or lower than the charge prohibition threshold, a battery pack that has become prohibited from discharging due to exceeding the discharge prohibition threshold can start charging with a short waiting time or without any waiting time, which is highly convenient. In addition, the first mode in which the discharge prohibition threshold of the battery packs 5-A and 5-B is higher than the charge prohibition threshold can also be selected, and it is also possible to suitably respond when it is desired to extend the dischargeable time, which is highly convenient.

[0058] (Embodiment 2) This embodiment has the same configuration as Embodiment 1 but different control. Hereinafter, the description will focus on the differences from Embodiment 1. FIG. 11 is a time chart showing the on / off of discharging, the on / off of charging, and the time change of temperature of battery packs 5-A and 5-B when discharging alternately from battery packs 5-A and 5-B in Embodiment 2. In this time chart, for each of battery packs 5-A and 5-B, the discharge prohibition threshold is set to T2 at the first discharge, and is increased to T1 at the next discharge. The following is a specific description.

[0059] The sub-control unit 80 starts discharging from battery pack 5-A ("Battery 1" in FIG. 11) at time t41. When the temperature of battery pack 5-A reaches T2 at time t42, the sub-control unit 80 stops discharging from battery pack 5-A and starts discharging from battery pack 5-B ("Battery 2" in FIG. 11).

[0060] When the temperature of battery pack 5-B reaches T2 at time t43, the sub-control unit 80 stops discharging from battery pack 5-B and starts discharging from battery pack 5-A. During the period from time t42 to t43, the temperature of battery pack 5-A, which has been stopped from discharging, has decreased. When the temperature of battery pack 5-A reaches T1 at time t44, the sub-control unit 80 stops discharging from battery pack 5-A and starts discharging from battery pack 5-B.

[0061] When the temperature of battery pack 5-B reaches T1 at time t45, the sub-control unit 80 stops discharging from battery pack 5-B. When the temperature of battery pack 5-A drops below T2 at time t46, the sub-control unit 80 starts charging battery pack 5-A.

[0062] FIG. 12 is a flowchart of charge / discharge control of battery packs 5-A and 5-B when discharging alternately from the battery packs 5-A and 5-B. The sub-control unit 80 sets the battery pack 5-A as the discharge target (S11) and performs discharge control (S12). The sub-control unit 80 continues discharging from the battery pack 5-A until the temperature of the battery pack 5-A exceeds T2 (No in S13). When the temperature of the battery pack 5-A exceeds T2 (Yes in S13), the sub-control unit 80 checks whether the battery pack 5-B is connected (S14).

[0063] When the battery pack 5-B is connected (Yes in S14), the sub-control unit 80 stops discharging from the battery pack 5-A, sets the battery pack 5-B as the discharge target, and performs discharge control (S15). The sub-control unit 80 continues discharging from the battery pack 5-B until the temperature of the battery pack 5-B exceeds T2 (No in S16). When the temperature of the battery pack 5-B exceeds T2 (Yes in S16), the sub-control unit 80 stops discharging from the battery pack 5-B, sets the battery pack 5-A as the discharge target, and performs discharge control (S17).

[0064] When the battery pack 5-B is not connected (No in S14), the sub-control unit 80 continues discharging from the battery pack 5-A and proceeds to S18. The sub-control unit 80 continues discharging from the battery pack 5-A until the temperature of the battery pack 5-A exceeds T1 (No in S18). When the temperature of the battery pack 5-A exceeds T1 (Yes in S18), the sub-control unit 80 checks whether the battery pack 5-B is connected (S19).

[0065] When the battery pack 5-B is connected (Yes in S19), the sub-control unit 80 stops discharging from the battery pack 5-A, sets the battery pack 5-B as the discharge target, and performs discharge control (S20). The sub-control unit 80 continues discharging from the battery pack 5-B until the temperature of the battery pack 5-B exceeds T1 (No in S21). When the temperature of the battery pack 5-B exceeds T1 (Yes in S21), the sub-control unit 80 stops discharging from the battery pack 5-B (S22).

[0066] When the battery pack 5-B is not connected (No in S19), the sub-control unit 80 proceeds to S22. In S22, the discharge from the battery pack 5-A is also stopped, and the discharges from both the battery packs 5-A and 5-B are stopped. When the temperature of the battery pack 5-A drops below T2 (Yes in S23), the sub-control unit 80 starts charging the battery pack 5-A (S24). When the temperature of the battery pack 5-A is not below T2 (No in S23), and when the temperature of the battery pack 5-B drops below T2 (Yes in S25), the sub-control unit 80 starts charging the battery pack 5-B (S26). When the temperatures of both the battery packs 5-A and 5-B are not below T2 (No in S23, No in S25), the sub-control unit 80 enters the charging standby state (S27).

[0067] According to the present embodiment, until the time t43 in FIG. 11, since the temperatures of both the battery packs 5-A and 5-B are T2 or lower, if the power assist stops by the time t43, both the battery packs 5-A and 5-B can be immediately charged, which is highly convenient. If the discharge from the battery pack 5-A is continued without switching the discharge target at the time t42, at the time t43, the temperature of the battery pack 5-A exceeds T2, and the battery pack 5-A cannot be charged. That is, according to the present embodiment, it is possible to ensure a longer time during which both the battery packs 5-A and 5-B are at a temperature at which they can be charged.

[0068] (Embodiment 3) In the above-described Embodiments 1 and 2, the charging unit 70 was included in the main body of the air compressor 1, whereas in the present embodiment, the circuit configuration corresponding to the charging unit 70 is included in a charger 70A that is separate from the main body of the air compressor. Hereinafter, the description will focus on the differences from Embodiment 1.

[0069] FIG. 13 is a circuit block diagram of a charger 70A among the electrical devices (a separate air compressor and a charger) according to Embodiment 3. The charger 70A is obtained by separately extracting the charging-related configuration from the air compressor 1 of Embodiment 1. The charger 70A charges the battery pack 5 with the power supplied from a commercial AC power supply 39A, which is an external AC power source. The charging control is performed by the control unit 80B. The number of battery packs 5 that can be simultaneously connected to the charger 70A may be plural.

[0070] FIG. 14 is a circuit block diagram of an auxiliary circuit unit 300A of the air compressor among the electrical devices according to Embodiment 3. The auxiliary circuit unit 300A is obtained by removing the charging-related configuration from the auxiliary circuit unit 300 of Embodiment 1. The sub-control unit 80A performs the same control as the sub-control unit 80 of Embodiment 1, except that it does not have a function related to charging control.

[0071] In the present embodiment, the same effects as those of Embodiment 1 can be achieved, except that in order to charge a battery pack whose temperature exceeds the discharge prohibition threshold value, it is necessary to disconnect it from the air compressor main body and connect it to the charger 70A. Also, in Embodiment 3, compared with Embodiment 1, since the operator needs to remove the battery packs 5-A and 5-B from the air compressor and attach them to the charger 70A after the discharge stops, the operator is likely to feel inconvenient when charging does not start immediately. According to the present embodiment, since charging starts immediately after the operator's operation of attaching the battery packs 5-A and 5-B to the charger 70A, it is more convenient for the operator than Embodiments 1 and 2.

[0072] As described above, the present invention has been described by taking the embodiments as examples. It is understood by those skilled in the art that various modifications are possible within the scope described in the claims for each component and each processing process of the embodiments. Hereinafter, modification examples will be mentioned.

[0073] The electrical device of the present invention is not limited to an air compressor, and may be other types such as various electric tools and lighting devices that operate with the power of a battery pack. Discharging from the battery pack is not limited to assisting an AC power source, and may be discharging when an AC power source is not used.

Description of Symbols

[0074] 1…Air compressor, 5, 5-A, 5-B…Battery pack, 10…Main body cover, 12a, 12b…Air tank, 13…Compression part, 14…Motor, 19…Operation panel part, 20…Storage case part, 31…Rectification part, 32…AC side power supply boost circuit, 33…Inverter part, 37…AC side load current detection part, 38…Boost voltage detection part, 40…Main control part, 45…Mounting part for battery pack, 46A, 46B…Battery voltage detection part, 50…Assist power supply part, 57…Assist current control part, 60…Assist voltage detection part, 70…Charging part, 80…Sub control part, 87A~87D…Relay, 90, 110…Circuit power supply part, 100…Communication circuit, 200…Main body circuit part, 300…Auxiliary circuit part.

Claims

1. A load unit that receives power and performs operations, A battery unit having a secondary battery and capable of supplying power to the load unit, A charging unit connected to a commercial power source and capable of charging the secondary battery by supplying power to the battery unit, A temperature detection unit that detects the temperature of the battery unit, A control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detection value of the temperature detection unit, When the detection value of the temperature detection unit exceeds a predetermined discharge prohibition threshold value, the control unit prohibits the power supply from the battery unit to the load unit, and when the detection value of the temperature detection unit exceeds a predetermined charge prohibition threshold value, the control unit prohibits the power supply from the charging unit to the battery unit, The discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value, An electric device main body having the load unit and the charging unit, A battery pack that is detachably attached to the electric device main body and has the battery unit and the temperature detection unit, The control unit, When power is supplied from the battery unit to the load unit, prohibits power supply from the charging unit to the battery unit, In a state where power supply from the battery unit to the load unit is not performed, if the detection value of the temperature detection unit does not exceed the charge prohibition threshold value, permits power supply from the charging unit to the battery unit, an electric device.

2. A load unit that receives power and performs operations, A battery unit having a secondary battery and capable of supplying power to the load unit, A charging unit connected to a commercial power source and capable of charging the secondary battery by supplying power to the battery unit, A temperature detection unit that detects the temperature of the battery unit, A control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detection value of the temperature detection unit, When the detection value of the temperature detection unit exceeds a predetermined discharge prohibition threshold value, the control unit prohibits the power supply from the battery unit to the load unit, and when the detection value of the temperature detection unit exceeds a predetermined charge prohibition threshold value, the control unit prohibits the power supply from the charging unit to the battery unit, The discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value, An electric device main body having the load unit, A first battery pack that is detachably attached to the electric device main body and has the battery unit and the temperature detection unit, A second battery pack that is detachably attached to the electric device main body and has the battery unit and the temperature detection unit, When power is supplied from the battery unit of the first battery pack to the load unit, if the detected value of the temperature detection unit of the first battery pack exceeds the discharge prohibition threshold value, the control unit prohibits power supply from the battery unit of the first battery pack to the load unit and permits power supply from the battery unit of the second battery pack to the load unit. Electrical equipment.

3. When the control unit prohibits power supply from the battery unit of the first battery pack to the load unit and prohibits power supply from the battery unit of the second battery pack to the load unit, the control unit raises the discharge prohibition threshold value and permits power supply from the battery unit of the first battery pack to the load unit. The electrical equipment according to claim 2.

4. The electrical equipment according to any one of claims 1 to 3, wherein a mode in which the discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value and a mode in which the discharge prohibition threshold value is higher than the charge prohibition threshold value are switchable.

5. A load unit that receives power and performs work, A battery unit having a secondary battery and capable of supplying power to the load unit, A charging unit connected to a commercial power source and capable of charging the secondary battery by supplying power to the battery unit, A temperature detection unit that detects the temperature of the battery unit, A control unit that controls the power supplied from the battery unit to the load unit and the power supplied from the charging unit to the battery unit according to the detected value of the temperature detection unit. When the detected value of the temperature detection unit exceeds a predetermined discharge prohibition threshold value, the control unit prohibits power supply from the battery unit to the load unit, and when the detected value of the temperature detection unit exceeds a predetermined charge prohibition threshold value, the control unit prohibits power supply from the charging unit to the battery unit. The discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value. The electrical equipment is capable of switching between a mode in which the discharge prohibition threshold value is equal to or lower than the charge prohibition threshold value and a mode in which the discharge prohibition threshold value is higher than the charge prohibition threshold value.

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