CN116352660A - Electric tool - Google Patents

Abstract

The application discloses an electric tool powered by an energy supply device, comprising: a housing; a first energy storage device and a second energy storage device; a driving circuit; a first control unit electrically connectable to the temperature detection module of the energy supply device to obtain a temperature of the energy supply device; when the temperature of the energy supply device is lower than a first preset temperature, the first control unit sequentially and circularly controls preset current to flow into the first energy storage device and the second energy storage device from the energy supply device and flow into the energy supply device from the second energy storage device and the first energy storage device by controlling the on or off state of the driving circuit until the temperature of the energy supply device is higher than or equal to a second preset temperature or the voltage drop slope of the energy supply device is lower than or equal to a first preset slope.

Description

Electric tool

Technical Field

The embodiment of the invention relates to the technical field of electric tool control.

Background

With the development of electric tools, intelligent control technology of the electric tools is increasingly widely used. For example, the controller is used for driving the motor to realize the characteristics of quick start, stable braking and the like of the electric tool.

However, when the existing electric tool works in a low-temperature environment, the battery function of the existing electric tool is easily limited, and the use of the electric tool is affected. For example, when charging at low temperature (assuming 0 ℃ or lower), lithium dendrites are easily formed at the negative electrode of the lithium battery, and the separator is pierced, which causes a safety problem for the battery. For another example, when discharging at low temperature (assuming below-10 ℃), the low temperature causes the battery voltage to drop too fast, and quickly drops to the low voltage protection point, thereby causing the battery to be unable to continue discharging, and affecting the use of the electric tool.

Disclosure of Invention

The invention provides an electric tool, which realizes the preheating treatment of paired energy supply devices so as to ensure the normal use of the electric tool.

An embodiment of the present invention provides an electric power tool powered by an energy supply device, including: a housing formed with a receiving chamber; the first energy storage device and the second energy storage device are arranged in the shell; the driving circuit is arranged in the shell; a first control unit electrically connectable to the temperature detection module of the energy supply device to obtain a temperature of the energy supply device; the energy supply device is characterized in that when the temperature of the energy supply device is lower than a first preset temperature, the first control unit controls the on or off state of the driving circuit, and sequentially and circularly controls preset current to flow into the first energy storage device and the second energy storage device from the energy supply device and flow into the energy supply device from the second energy storage device and the first energy storage device until the temperature of the energy supply device is higher than or equal to a second preset temperature or the voltage drop slope of the energy supply device is lower than or equal to a first preset slope.

In one embodiment, the power tool further comprises a motor housed within the housing, the motor including a winding, the first energy storage device being the winding.

In an embodiment, the second energy storage device is a capacitive element, the second energy storage device being connected in parallel with the driving circuit.

In one embodiment, the drive circuit multiplexes the drive circuit of the motor, including an upper bridge including at least two transistors and a lower bridge including at least two transistors.

In an embodiment, the first control unit turns on or off both transistors of the upper bridge synchronously; the first control unit turns on or off both transistors of the lower bridge synchronously.

In an embodiment, the electric tool further includes a first switch disposed between the energy supply device and the driving circuit, for switching on or off the power supply of the driving circuit by the energy supply device; when the temperature of the energy supply device is lower than a first preset temperature, the first control unit controls the first switch to be closed.

In one embodiment, the driving circuit includes a first transistor, a second transistor, a third transistor, and a fourth transistor; the first control unit controls the first transistor and the second transistor to be closed, so that the energy supply device, the first energy storage device, the first transistor and the second transistor form a first current loop, and current flows into the first energy storage device from the energy supply device; the energy supply device, the first energy storage device, the third transistor, the fourth transistor and the second energy storage device form a second current loop by controlling the first transistor and the second transistor to be disconnected, so that current flows into the second energy storage device from the energy supply device; forming a third current loop by controlling the third transistor and the fourth transistor to be closed, so that current flows from the second energy storage device to the energy supply device; the first energy storage device, the energy supply device, the first transistor and the second transistor form a fourth current loop by controlling the third transistor and the fourth transistor to be turned off, so that current flows from the first energy storage device to the energy supply device.

In an embodiment, the electric tool further includes a power-on unit, and the power-on unit is configured to send a first signal to the first control unit, and when the first control unit receives the first signal and the temperature of the energy supply device is lower than a first preset temperature, control the driving circuit to heat the energy supply device.

In an embodiment, the power tool further includes a wireless communication interface, where the wireless communication interface is configured to communicatively connect the power tool to the remote device, and send the first signal to the first control unit when the power-on unit receives the standby command sent by the remote device.

In an embodiment, the electric tool further includes a fault detection unit, the fault detection unit detects a current of the first energy storage device, and the first control unit performs fault judgment by comparing the detected current with a preset current, and controls the first switch to be turned off when the fault is judged.

In one embodiment, an energy supply device includes a first battery pack and a second battery pack, and an electric tool includes: a housing; a motor including a winding; an inverter circuit including a plurality of switches; a control unit configured to be electrically connected with the temperature detection module to acquire a temperature of the energy supply device; when the temperature of the energy supply device is lower than a first preset temperature, the control unit controls the switches to be turned on or off, so that electric energy is transferred between the first battery pack and the second battery pack through the windings until the temperature of the energy supply device is higher than or equal to a second preset temperature or the voltage drop slope of the energy supply device is lower than or equal to the first preset slope.

The electric tool provided by the invention can solve the problem that in the prior art, under the low-temperature environment, the charge and discharge of the electric tool are easy to be limited, so that the service performance of the electric tool is influenced, and the electric tool preheats the energy supply device when in use in the low-temperature environment, so that the energy supply device can be charged and discharged normally in the low-temperature environment, and the normal use of the electric tool is not influenced.

Drawings

FIG. 1 is a schematic diagram of the basic architecture of an embodiment of the present invention;

FIG. 2 is a perspective view of a power tool in an embodiment of the invention;

FIG. 3 is a schematic diagram of a preheating control circuit for an energy delivery device in accordance with an embodiment of the present invention;

FIG. 4A is a schematic diagram of a first current loop of the circuit of FIG. 3;

FIG. 4B is a schematic diagram of a second current loop of the circuit of FIG. 3;

FIG. 4C is a schematic diagram of a third current loop of the circuit of FIG. 3;

FIG. 4D is a schematic diagram of a fourth current loop of the circuit of FIG. 3;

FIG. 5 is a schematic diagram of a wireless communication mode of the power tool according to an embodiment of the invention;

fig. 6 is a perspective view of a charging device in an embodiment of the invention;

FIG. 7 is a schematic diagram of a preheating control circuit for another energy delivery device in an embodiment of the present invention;

FIG. 8 is a schematic diagram of a preheating control circuit for another energy delivery device in an embodiment of the present invention;

FIGS. 9A-9C are schematic diagrams of preheating control circuits for several other energy delivery devices in accordance with embodiments of the present invention;

FIG. 10 is a perspective view of an energy delivery device in an embodiment of the present invention;

FIG. 11 is a perspective view of the energy delivery device of FIG. 10 with the housing removed;

FIG. 12 is a schematic diagram of a preheating control circuit for another energy delivery device in an embodiment of the present invention;

FIG. 13 is a schematic diagram of a preheating control circuit for another energy delivery device in an embodiment of the present invention;

FIG. 14A is a schematic diagram of a first current loop of the circuit of FIG. 13;

FIG. 14B is a schematic diagram of a second current loop of the circuit of FIG. 13;

FIG. 14C is a schematic diagram of a third current loop of the circuit of FIG. 13;

fig. 14D is a schematic diagram of a fourth current loop of the circuit of fig. 13.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

Fig. 1 is a schematic diagram of the basic architecture of the present invention. Referring to fig. 1, the basic elements of the present invention include: an energy supply device 100; a temperature detection module 200 electrically connected to the power supply device 100 for detecting a temperature of the power supply device 100; the preheating control module 300 is electrically connected to the energy supply device 100 and the temperature detection module 200, and is used for controlling the energy supply device 100 to perform alternating-current preheating with a preset current until the temperature of the energy supply device 100 is greater than or equal to a second preset temperature when the temperature of the energy supply device 100 is lower than the first preset temperature. In one embodiment, the preset current is a small current, which has the advantage that the energy supply device is slowly heated in a low-temperature environment, so that the phenomenon that the energy supply device burns due to instantaneous large current is avoided.

The power supply device 100 may be composed of a ternary lithium battery and/or a lithium iron phosphate battery, among others. As shown in fig. 10 to 11, the power supply device 100 includes a cell module 102, the cell module 102 includes a plurality of series/parallel cells 103, and the cells 103 may be lithium ion batteries, such as lithium iron phosphate batteries, for storing electric power, and the chemical principles of the cells 103 are not limited in this application. The power supply device 100 may be a removable battery pack or may be incorporated into the power tool 400, and the specific shape, size, nominal voltage, etc. of the power supply device 100 are not limited in this application. The temperature detection module 200 may be a temperature sensor, e.g., an RTD sensor, a thermistor, etc. The temperature detection module 200 may be provided inside the power supply device 100. The first preset temperature is a temperature at which the charge and discharge of the power supply device 100 is limited, and its value is generally a low temperature value or a low temperature range, for example, 0 ℃, -10 ℃, etc. The second preset temperature is greater than the first preset temperature, and is a temperature at which the energy supply device 100 charges and discharges normally, and is usually a low temperature value or a low temperature range. The first preset temperature and the second preset temperature may also be different according to the chemical principle of the specific energy supply device 100, etc., and the specific values of the first preset temperature and the second preset temperature are not limited in this application.

As shown in fig. 2, the power supply 100 may be connected to the power tool 400 to supply power to the power tool 400. The power tool 400 includes a housing 401, the housing 401 being formed with a receiving cavity to receive various components of the power tool 400. The power tool 400 may be a small hand-held power tool, such as a power screwdriver, an electric drill, an electric hammer, a pruner, a blower, etc., or a large floor-standing power tool, such as a mower, a snowplow, a tractor, etc. The power supply device 100 may be provided outside the power tool 400 and detachably connected to the housing 401; may be provided inside the power tool 400 and surrounded by the housing 401. When the power supply device 100 is connected to the power tool 400, the connection terminal 104 of the power supply device 100 is connected to the connection terminal of the power tool 400, specifically, the positive electrode terminal of the power supply device 100 is electrically connected to the positive electrode terminal of the power tool 400, the negative electrode terminal of the power supply device 100 is electrically connected to the negative electrode terminal of the power tool 400, the information terminal of the power supply device 100 is electrically connected to the information terminal of the power tool 400, and the real-time temperature of the power supply device 100 acquired by the temperature detection module 200 can be transmitted to the power tool 400 via the information terminal. Of course, the temperature detection module 200 may be provided on the electric power tool 400, for example, on the surface of the housing 401, and the temperature of the power supply device 100 may be detected by the contact surface between the electric power tool 400 and the power supply device 100. In general, the charge/discharge electrode of the energy supply device 100 is susceptible to temperature, for example, in the case of a lithium battery as an energy supply device, when the lithium battery is discharged at a low temperature (for example, at-10 ℃ or lower), the viscosity of the electrolyte increases, the ion conduction speed decreases, and the external circuit electron transfer speed is mismatched, so that the battery is severely polarized, and the charge/discharge capacity is drastically reduced. The low temperature causes the voltage to drop too quickly and quickly to drop to a low voltage protection point, thereby causing the battery to be unable to continue discharging, which can affect the use of the power tool 400.

To solve this problem, the present invention can realize: when the electric power tool 400 is used in a low-temperature environment, the temperature of the power supply device 100 is detected in real time by the temperature detection module 200 and transmitted to the preheating control module 300. The preheating control module 300 is electrically connected to the temperature detection module 200 and the energy supply device 100, respectively, when the electric tool 400 needs to be started, the preheating control module 300 receives the temperature of the energy supply device 100 sent by the temperature detection module 200 and determines the temperature, when the temperature of the energy supply device 100 is lower than a first preset temperature, the energy supply device 100 is controlled to perform alternating-current preheating with a preset current, when the current repeatedly flows out of the energy supply device 100 and flows in, the temperature of the energy supply device 100 is increased, and when the temperature of the energy supply device 100 is higher than or equal to a second preset temperature, the temperature of the energy supply device 100 can meet the temperature requirement of normal charge and discharge, so that the alternating-current preheating of the energy supply device 100 is stopped at the moment. Note that, in the present application, the current "flowing into" the energy supply device 100 means that the current flows into the positive electrode of the energy supply device 100, that is, in the opposite direction to the current "flowing out" from the energy supply device 100; and does not mean that current flows back to the negative electrode of the power supply device 100 when the power supply device 100 discharges. By repeating the current flowing out and in from the power supply device 100, the power supply device 100 is preheated, so that the power supply device 100 can be charged and discharged normally even in a low-temperature environment, and normal use of the power tool 400 is not affected.

It is noted that, when the power supply device 100 is subjected to ac excitation, the diffusion process of lithium ions in the electrode active material particles is alternately performed, so that after the power supply device 100 performs an electrochemical reaction of a lithium intercalation process for a certain period of time at a low temperature, a delithiation electrochemical reaction occurs randomly, lithium generated by the lithium intercalation reaction is consumed by a subsequent delithiation reaction, i.e., lithium generated and consumed every cycle is balanced, and thus, the capacity of the power supply device 100 is not permanently damaged, that is, the life of the power supply device 100 is not affected. In this embodiment, the ac excitation at frequencies of 10Hz and above does not have any effect on the capacity and impedance of the power supply device when the power supply device is heated.

In one embodiment, the preheat control module 300 is disposed within the power tool 400. That is, the electronic components included in the preheating control module 300 are disposed in the electric tool 400. Still further, the preheating control module 300 multiplexes a portion of the electronic components of the power tool 400 itself. Fig. 3 is a schematic diagram of a preheating control circuit of an energy supply device according to an embodiment of the present invention, fig. 4A is a schematic circuit diagram of a first current loop of the circuit shown in fig. 3, fig. 4B is a schematic circuit diagram of a second current loop of the circuit shown in fig. 3, fig. 4C is a schematic circuit diagram of a third current loop of the circuit shown in fig. 3, and fig. 4D is a schematic circuit diagram of a fourth current loop of the circuit shown in fig. 3.

As an embodiment, referring to fig. 3 and 4A to 4D, the preheating control module 300 includes a first control unit 311, a first switch S1, a driving circuit 312, a first energy storage device 313, and a second energy storage device 314. The first switch S1 is disposed between the power supply device 100 and the driving circuit 312, and is used to switch on or off the power supply of the power supply device 100 to the driving circuit 312. The first control unit 311 is electrically connected to the temperature detection module 200, the first switch S1, and the driving circuit 312, and is configured to control, when the temperature of the energy supply device 100 is lower than a first preset temperature, to sequentially circulate and control a preset current (for example, a small current) from the energy supply device 100 to the first energy storage device 313 and the second energy storage device 314 and from the second energy storage device 314 and the first energy storage device 313 to the energy supply device 100 at a certain time interval by controlling on or off of the driving circuit 312 after the first switch S1 is controlled to be closed until the temperature of the energy supply device 100 is greater than or equal to a second preset temperature. At this time, the temperature of the power supply device 100 may satisfy the temperature required for normal charge and discharge, and the first control unit 311 controls the first switch S1 to be turned off so that the power supply device 100 stops ac preheating. Of course, the preheating control module 300 may not include the first switch S1, and the first control unit 311 may control the driving circuit 312 to achieve the above-described functions.

Optionally, the first control unit 311 is further electrically connected to the power-on unit 410 of the electric tool 400, when the electric tool 400 needs to be started, the first control unit 311 receives a first signal sent by the power-on unit 410, and then, the first control unit 311 obtains the temperature of the energy supply device 100 through the temperature detection module 200 and determines the temperature, when the temperature of the energy supply device 100 is greater than or equal to a first preset temperature, the electric tool 400 is allowed to directly enter an on/standby state, and when the temperature of the energy supply device 100 is lower than the first preset temperature, the energy supply device 100 is preheated. The power-on unit 410 has various settings according to the power tool 400. For example, for a power tool having a start key, such as a mower, a snowplow, etc., the start unit 410 may send a first signal to the first control unit 311 when the user inserts the key, so that when the user triggers the start button or starts the trigger, the preheating control module 300 starts preheating the power supply device 100 in advance, and even the preheating control module 300 has completed preheating the power supply device 100, so that the user does not need to wait for an additional time, or only needs to wait for a short time, and the corresponding power tool can be put into an operation mode, that is, a walk motor is started, and a motor of a mowing element or a snow shoveling element is started. For electric tools with dual power-on protection such as chain saw and pruner, the power-on unit 410 may send a first signal to the first control unit 311 when a user triggers one of the dual power-on switches, so that when the user correctly triggers the dual power-on switch, the corresponding electric tool can be put into a working mode only by waiting for a short time. For a power tool powered on by a key such as a screwdriver or a percussion drill, the power-on unit 410 may send a first signal to the first control unit 311 when the user activates the power-on switch, and of course, when the power tool is in a low-temperature state, the user may need to wait for a certain time for the preheating control module 300 to complete preheating of the energy supply device 100.

In one embodiment, as shown in fig. 5, the power tool 400 is provided with a wireless communication interface 420, the wireless communication interface 420 being configured to enable the power tool 400 to establish a communication connection with a remote device or an internet server. Specifically, the wireless communication interface 420 may be a short-range communication device such as bluetooth, infrared, etc., so that the electric tool 400 establishes a communication connection with a remote controller, a smart sound, etc. device 701, at this time, the user may send a standby command to the electric tool 400 through the remote controller, etc.; the wireless communication interface 420 may also be a wifi or other long-distance communication device, so that the electric tool 400 may establish a communication connection with the mobile phone, the tablet or other terminal 702 through the internet server, and at this time, the user may send a standby command to the electric tool 400 through the mobile phone, the tablet or other terminal. The wireless communication interface 420 may be provided with both of them. The power-on unit 410 sends a first signal to the first control unit 311 when receiving the standby command, so that when the user triggers the start switch of the electric tool 400, the preheating control module 300 has already started preheating the energy supply device 100 in advance, and even the preheating control module 300 has already completed preheating the energy supply device 100, so that the user does not need to wait for additional time, or only needs to wait for a short time, and the corresponding electric tool can be put into the working mode. It should be understood that the first signal as described above is a "ready-to-start" signal sent by the start-up unit 410 to the first control unit 311, rather than a formal start-up signal for controlling the motor to operate, after the first control unit 311 receives the first signal sent by the start-up unit 410, the temperature detection module 200 obtains the temperature of the energy supply device 100, determines the temperature, and optionally performs ac preheating on the energy supply device 100. When the power supply device 100 meets the normal discharging condition, the first control unit 311 gives a feedback corresponding to the power-on unit 410, for example, a second signal, and the power-on unit 410 comprehensively determines whether the power-on can be started according to other conditions of the electric tool 400.

Illustratively, the time interval between controlling the flow of the preset current from the energy delivery device 100 to the first energy storage device 313 and controlling the flow of the preset current from the energy delivery device 100 to the second energy storage device 314 is a first preset time interval; the time interval between controlling the flow of the preset current from the energy supply device 100 into the second energy storage device 314 and controlling the flow of the preset current from the second energy storage device 314 into the energy supply device 100 is also the first preset time interval; the time interval between controlling the inflow of the preset current from the second energy storage device 314 to the energy supply device 100 and controlling the inflow of the preset current from the first energy storage device 313 to the energy supply device 100 is also the first preset time interval; the time interval between controlling the flow of the preset current from the first energy storage device 313 into the energy supply device 100 and controlling the flow of the preset current from the energy supply device 100 into the first energy storage device 313 is also the first preset time interval. That is, the four processes of fig. 4A to 4D are circulated in a preset order, and the time intervals of the four processes are equal, wherein the specific duration of the first preset time interval may be set according to the specific situation, which is not particularly limited herein.

It should be noted that, the time intervals between the four processes of controlling the preset current to flow from the energy supply device 100 into the first energy storage device 313, controlling the preset current to flow from the energy supply device 100 into the second energy storage device 314, controlling the preset current to flow from the second energy storage device 314 into the energy supply device 100, and controlling the preset current to flow from the first energy storage device 313 into the energy supply device 100 are merely exemplary and set to the same first preset time interval, may also be different time intervals, and may be set according to actual situations, and is not limited herein specifically.

Alternatively, referring to fig. 3 and 4A to 4D, the driving circuit 312 includes at least a first transistor M1, a second transistor M2, a third transistor M3, and a fourth transistor M4; the first control unit 311 controls the first transistor M1 and the second transistor M2 to be turned on, so that the energy supply device 100, the first energy storage device 313, the first transistor M1 and the second transistor M2 form a first current loop P1, and a current flows from the energy supply device 100 into the first energy storage device 313; the first control unit 311 controls the first transistor M1 and the second transistor M2 to be turned off, so that the energy supply device 100, the first energy storage device 313, the third transistor M3, the fourth transistor M4, and the second energy storage device 314 form a second current loop P2, and a current flows from the energy supply device 100 into the second energy storage device 314; the first control unit 311 controls the third transistor M3 and the fourth transistor M4 to be turned on, so that the first energy storage device 313, the energy supply device 100, the third transistor M3, the fourth transistor M4, and the second energy storage device 314 form a third current loop P3, and current flows from the second energy storage device 314 to the energy supply device 100; the first control unit 311 controls the third transistor M3 and the fourth transistor M4 to be turned off, thereby forming a fourth current loop P4 by the first energy storage device 313, the energy supply device 100, the first transistor M1, and the second transistor M2, and allowing current to flow from the first energy storage device 313 into the energy supply device 100.

The first transistor M1, the second transistor M2, the third transistor M3, and the fourth transistor M4 may be transistors or MOS transistors. The control terminal of the first transistor M1 is electrically connected to the first control unit 311 (not shown), and a first diode D1 is connected in parallel between the first terminal and the second terminal of the first transistor M1; the control terminal of the second transistor M2 is electrically connected to the first control unit 311 (not shown), and a second diode D2 is connected in parallel between the first terminal and the second terminal of the second transistor M2; a control terminal of the third transistor M3 is electrically connected to the first control unit 311 (not shown), and a third diode D3 is connected in parallel between the first terminal and the second terminal of the third transistor M3; the control terminal of the fourth transistor M4 is electrically connected to the first control unit 311 (not shown), and a fourth diode D4 is connected in parallel between the first terminal and the second terminal of the fourth transistor M4. The first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 may be parasitic diodes of the first transistor M1, the second transistor M2, the third transistor M3, and the fourth transistor M4.

When the first control unit 311 receives the power-on signal of the power-on unit 410 and the temperature of the energy supply device 100 is lower than the first preset temperature, the first control unit 311 controls the first switch S1 to be closed. Then, by controlling the first transistor M1 and the second transistor M2 to be turned on and the other transistors to be turned off, such that the current flows from the energy supply device 100 to the first energy storage device 313 to charge the first energy storage device 313, the current flows from the first energy storage device 313 to flow back to the energy supply device 100 through the first transistor M1 and the second transistor M2, respectively, to form a first current loop P1. After the first current loop P1 continues for the first preset time interval, the first control unit 311 controls the first transistor M1 and the second transistor M2 to be turned off, so that current flows from the energy supply device 100 to the first energy storage device 313 to charge the first energy storage device 313, and since the first transistor M1 and the second transistor M2 are turned off and the current cannot be transient, the current flows from the first energy storage device 313 to the second energy storage device 314 through the third diode D3 and the fourth diode D4 respectively to charge the second energy storage device 314, and then flows from the second energy storage device 314 to the energy supply device 100 to form the second current loop P2. After the second current loop P2 continues for the first preset time interval, the first control unit 311 controls the third transistor M3 and the fourth transistor M4 to be turned on and the other transistors to be turned off, and as the third transistor M3 and the fourth transistor M4 are turned on, the second energy storage device 314 discharges, and the discharge current flows into the first energy storage device 313 through the third transistor M3 and the fourth transistor M4, respectively, then flows into the energy supply device 100 from the first energy storage device 313 to charge the energy supply device 100, and then flows out of the energy supply device 100 and flows back to the second energy storage device 314 to form the third current loop P3. After the third current loop P3 continues for the first preset time interval, the first control unit 311 controls the third transistor M3 and the fourth transistor M4 to be turned off, the first energy storage device 313 discharges, the discharge current flows into the energy supply device 100 due to the third transistor M3 and the fourth transistor M4 being turned off, the energy supply device 100 is charged, and the current flows from the energy supply device 100 and flows back to the first energy storage device 313 through the first diode D1 and the second diode D2, respectively, after the current cannot be transient, due to the third transistor M3 and the fourth transistor M4 being turned off, so as to form the fourth current loop P4. After the fourth current loop P4 continues for the first preset time interval, the first control unit 311 controls to switch to the first current loop P1, and sequentially circulates, so as to implement ac preheating of the energy supply device, so as to implement preheating treatment of the energy supply device.

By configuring the on-voltage of each transistor, the performance parameter of the energy storage device, the rated voltage of the energy supply device 100, and the like, the first current loop P1, the second current loop P2, the third current loop P3, and the fourth current loop P4 can be charged and discharged according to a preset current, so that the energy supply device 100 can be slowly heated in a low-temperature environment, and no burning out caused by a large current can be generated instantaneously. The value of the preset current may be set according to the actual situation, which is not specifically limited herein.

The first control unit 311 may be a single chip microcomputer, or may be a subroutine loaded on a processor of the electric tool 400. In one embodiment, the power tool 400 includes a motor and a driving circuit, the first energy storage device 313 is a motor winding of the power tool 400, the second energy storage device 314 is a capacitive element C1 of the power tool 400, and the capacitive element C1 is connected in parallel with the driving circuit. The motor may be a three-phase motor and the first energy storage device 313 is a three-phase winding of the motor. As shown in fig. 4, the currents of the first, second, third, and fourth current loops P1, P2, P3, and P4 all flow through all windings of the motor. For three-phase windings, the currents of the first, second, third, and fourth current loops P1, P2, P3, and P4 flow in from one of the phase windings and flow out from the other two phase windings. The first transistor M1, the second transistor M2, the third transistor M3, and the fourth transistor M4 are all driving circuit switches of the motor, that is, the driving circuit 312 multiplexes the driving circuits of the motor of the power tool 400. From the perspective of the driving circuit of the motor, the first transistor M1 and the second transistor M2 belong to a lower bridge, and the third transistor M3 and the fourth transistor M4 belong to an upper bridge. In the four processes shown in fig. 4, the upper bridge, that is, the third transistor M3 and the fourth transistor M4, are synchronously turned on or off under the control of the first control unit 311; the lower bridge, i.e., the first transistor M1 and the second transistor M2, is synchronously turned on or off under the control of the first control unit 311. Also, the first control unit 311 does not control the upper and lower bridges of the driving circuit at the same time. The present embodiment maximally utilizes the components of the motor winding and the driving circuit itself, and thus, the present embodiment multiplexes the motor winding, the driving circuit and the capacitive element of the power tool 400 itself, and has low modification cost and high practicality while providing the low-temperature preheating function of the power supply device 100. Wherein the motor, the driving circuit, the capacitive element C1, etc. are disposed inside the housing 401 of the electric tool 400. The power supply device 100 is detachably mounted to the power tool 400, and for some power tools, such as a mower, the power supply device 100 may be disposed inside the housing 401 of the power tool 400; of course, for some other power tools, such as power screwdrivers, the power supply 100 is disposed outside the housing 401 of the power tool 400.

In another embodiment, the preheating control module 300 may also utilize the motor windings and drive circuitry of the power tool 400 to effect preheating of the power supply 100 in the form of DC pulses. Specifically, when the temperature of the energy supply device 100 is lower than the first preset temperature, the first control unit 311 controls the transistor of the motor driving circuit to be turned on or off at a certain frequency, so that the temperature of the energy supply device 100 is increased by the short-duration high-frequency discharge until the temperature of the energy supply device 100 is greater than or equal to the second preset temperature. That is, the pulse current for preheating the energy supply device 100 includes an ac pulse current or a dc pulse current. The present application is not limited to the waveform of the pulse current, but can be sinusoidal, square wave, and various other waveforms. The frequency, amplitude, duty cycle of the pulse current may be either fixed or variable. The pulse current control can adopt modes of constant frequency variable PWM, variable frequency, wave-by-wave current limiting and the like, and the details are not described herein.

In an embodiment, the preheating control module 300 further includes a fault detection unit 315, for example, when the first current loop P1, the second current loop P2, the third current loop P3, or the fourth current loop P4 is not charged or discharged according to the preset current, it may be determined that the preheating control module 300 has a fault. In particular, the fault detection unit 315 may comprise a current detection resistor for detecting the current through the first energy storage device 313, i.e. the three-phase winding of the motor; by comparing the preset current with the real-time current detected by the current detection resistor, it is determined whether the warm-up control module 300 has a fault. Alternatively, the fault detection unit 315 may comprise a hall sensor for acquiring the current through the first energy storage device 313, i.e. the three-phase winding of the motor; the real-time current is calculated according to the result of the hall sensor and compared with the preset current, thereby judging whether the preheating control module 300 fails. When the fault detection unit 315 determines that the preheating control module 300 has a fault, the first control unit 311 turns off the first switch S1, and stops the preheating of the power supply apparatus 100, thereby avoiding damage to the power supply apparatus 10 and the power tool 400. Generally speaking, many electric tools 400 have a function of acquiring the current of the motor winding, in which the current detecting resistor or the hall sensor is a common means for acquiring the current of the motor winding, so the fault detecting unit 315 provides the safety guarantee for the preheating control module 300, and meanwhile, the improvement cost is low, and the practicability is high. It will be appreciated that the fault detection unit 315 may also be disposed within the housing 401 of the power tool 400.

Fig. 7 is a schematic diagram of a control circuit for preheating another energy supply device 100 according to an embodiment of the present invention. As an embodiment, alternatively, referring to fig. 7, the preheating control module 300 includes a second control unit 321, a power supply unit 322, and a first resistor R1, a second switch S2, and a third switch S3, and the second control unit 321 is connected to the temperature detection module 200 for controlling the on or off of the second switch S2 and/or the third switch S3 and sequentially and cyclically controlling a preset current to flow from the power supply unit 322 into the energy supply device 100 and from the energy supply device 100 into the first resistor R1 at certain time intervals until the temperature of the energy supply device 100 is greater than or equal to a second preset temperature when the temperature of the energy supply device 100 is lower than the first preset temperature.

Optionally, the present invention further includes a charging device 500 paired with the energy supply device, and as shown in fig. 6, the energy supply device 100 may be connected to the charging device 500, thereby charging the energy supply device 100. The charging device 500 may be a charger, a power station, or the like. Optionally, the second control unit 321, the power supply unit 322, the first resistor R1, the second switch S2, and the third switch S3 are integrated in the charging device 500. Specifically, the charging device 500 includes a housing 501, and the second control unit 321, the power supply unit 322, the first resistor R1, the second switch S2, and the third switch S3 are all accommodated in an accommodating chamber formed by the housing 501. The second control unit 321 may be a single chip microcomputer, or may be a subroutine loaded on the processor of the charging device 500. The power supply unit 322 is a power conversion device of the charging device 500, and may include a rectifier bridge, a step-down transformer, a filter, and the like.

Alternatively, the temperature detection module 200 may be integrated in the power supply 100. When the energy supply device 100 is connected to the charging device 500, the connection terminal 104 of the energy supply device 100 is connected to the connection terminal 502 of the charging device 500, specifically, the positive terminal of the energy supply device 100 is electrically connected to the positive terminal of the charging device 500, the negative terminal of the energy supply device 100 is electrically connected to the negative terminal of the charging device 500, the information terminal of the energy supply device 100 is electrically connected to the information terminal of the charging device 500, and the real-time temperature of the energy supply device 100 acquired by the temperature detection module 200 can be transmitted to the charging device 500 through the information terminal. Of course, the temperature detection module 200 may be provided on the charging device 500, for example, on the surface of the housing 501, and the temperature of the energy supply device 100 may be detected by the contact surface between the charging device 500 and the energy supply device 100. In general, the charge/discharge electrode of the energy supply device 100 is susceptible to temperature, for example, in the case of a lithium battery as an energy supply device, when the lithium battery is charged at a low temperature (for example, 0 ℃ or lower), the viscosity of the electrolyte increases, the ion conduction speed decreases, and the external circuit electron transfer speed is mismatched, so that the battery is severely polarized, and the charge/discharge capacity is drastically reduced. Particularly when charged at low temperatures, lithium ions can easily form lithium dendrites on the surface of the negative electrode, leading to failure of the battery.

Specifically, after the power supply device 100 is inserted into the charging device 500, the temperature detection module 200 detects the temperature of the power supply device 100 and transmits it to the second control unit 321. When the temperature of the energy supply device 100 is lower than the first preset temperature, the second control unit 321 controls the second switch S2 to be turned on and the third switch S3 to be turned off so that a preset current flows into the energy supply device 100 from the power supply unit 322, when the second preset time interval is continued, the second control unit 321 controls the second switch S2 to be turned off and the third switch S3 to be turned on so that a preset current flows into the first resistor R1 from the energy supply device 100, when the second preset time interval is continued, the second control unit 321 controls the second switch S2 to be turned on and the third switch S3 to be turned off again so that a preset current flows into the energy supply device 100 from the power supply unit 322, and thus the cycle is performed to perform alternating-current preheating on the energy supply device 100 until the temperature of the energy supply device 100 is greater than or equal to the second preset temperature, and the second control unit 321 controls the second switch S2 and the third switch S3 to be turned off so that the alternating-current preheating is stopped. This realizes the preheating treatment of the energy supply device 100 in the low-temperature environment.

It should be noted that, the time interval between the two processes of controlling the preset current to flow from the power supply unit 322 to the power supply device 100 and controlling the preset current to flow from the power supply device 100 to the first resistor R1 is only an exemplary second preset time interval that is set to be the same, and may also be different time intervals, and the specific time interval may be set according to the actual situation, which is not limited herein specifically.

The charging current of the energy supply device 100 is related to the discharging current of the power unit 321, the discharging current is a preset current, and the specific value is related to the actual situation, which is not limited herein. Similarly, the charging current of the power unit 321 is related to the discharging current of the energy supply device 100, the discharging current is a preset current, and the specific value is related to the actual situation, which is not limited herein.

Fig. 8 is a schematic diagram of a preheating control circuit of another energy supply device provided in an embodiment of the present invention. As an embodiment, optionally, referring to fig. 8, the preheating control module 300 includes a third control unit 331, a voltage acquisition unit 332, and an alternating current generation unit 333; the voltage acquisition unit 332 is configured to acquire a voltage of the energy supply device 100; the third control unit 331 is configured to output a control signal to the alternating current flow generating unit 333 according to the voltage of the energy supply device 100 and a preset voltage when the temperature of the energy supply device 100 is lower than a first preset temperature; the alternating current generating unit 333 is configured to adjust the output alternating current according to the control signal to enable the preset current to flow into and out of the energy supply device 100 until the temperature of the energy supply device 100 is greater than or equal to the second preset temperature. Alternatively, the conversion frequency of the alternating current output by the alternating current generation unit 333 is 10Hz or more. Optionally, the third control unit 331, the voltage acquisition unit 332, and the alternating current generation unit 333 are integrated in the charging device 500. That is, the third control unit 331, the voltage acquisition unit 332, and the alternating current generation unit 333 are all accommodated in the accommodation chamber formed by the housing 501.

The third control unit 331 may be a single-chip microcomputer, or may be a subroutine loaded on the processor of the charging device 500. The voltage acquisition unit 332 may be a voltage transformer. The preset current is related to selection of circuit components, etc., and may be specifically set according to actual situations, which is not specifically limited herein. The preset voltage is related to an actual circuit, and may be specifically set according to an actual situation, which is not specifically limited herein. When the power supply device 100 is inserted into the charging device, the temperature detection module 200 detects the temperature of the power supply device 100 and transmits the detected temperature to the third control unit 331, and the voltage acquisition unit 332 detects the voltage of the power supply device 100 in real time and transmits the detected voltage to the third control unit 331. When the temperature of the energy supply device 100 is lower than the first preset temperature, the third control unit 331 compares the voltage of the energy supply device 100 with the preset voltage to output a control signal (for example, a PWM wave signal) to the alternating current generating unit 333, and the alternating current generating unit 333 adjusts the output alternating current according to the control signal to make the preset current repeatedly flow into and out of the energy supply device 100, so as to perform the preheating treatment on the energy supply device 100, until the temperature of the energy supply device 100 is greater than or equal to the second preset temperature, and the third control unit 331 stops outputting the control signal to stop performing the alternating current preheating on the energy supply device 100.

Optionally, with continued reference to fig. 8, the alternating current generating unit 333 includes at least a third energy storage device, a fifth transistor M5 and a sixth transistor M6, and the third control unit 331 is configured to adjust on or off of the fifth transistor M5 and/or the sixth transistor M6 according to a control signal, so that a preset current flows into and out of the energy supply device 100 and/or the third energy storage device. The third energy storage device is a first inductive element L1. The fifth transistor M5 and the sixth transistor M6 may be transistors or MOS transistors. Referring to fig. 8, the alternating current generation unit 333 further includes a capacitive element C2, a second resistor R2, a third resistor R3, and a fourth resistor R4. Wherein the capacitive element C2 is used for filtering. The second resistor R2, the third resistor R3 and the fourth resistor R4 are used for voltage division.

Fig. 9 is a further expanded embodiment of the ac preheating of the energy supply device 100 by the charging device 500, wherein the power source of the charging device 500 is mains ac, comprising at least a live wire and a neutral wire, in which L represents the live wire and N represents the neutral wire. In fig. 9A, the ac mains current is rectified to DC by a rectifying unit, and then flows into the energy supply device 100 via a bi-directional DC-DC converter, such as a Buck/Boost bi-directional converter. The bidirectional DC-DC converter is a double-phase limit operation of the DC-DC converter, and the input voltage and the output voltage of the bidirectional DC-DC converter have unchanged polarities, but the directions of the input current and the output current can be changed, so that the preset current repeatedly flows into and out of the energy supply device 100, and the alternating current preheating of the energy supply device 100 is realized. Alternatively, the bi-directional DC-DC converter is connected in parallel with a capacitor that is taken up when current flows from the energy delivery device 100. Fig. 9B adds a PFC unit (power factor correction) to the fig. 9A unit, thereby suppressing harmonics and improving the power utilization. The PFC unit can be composed of an inductance, a capacitance and an electronic component, is small in size, and can compensate the phase difference between current and voltage by adjusting the waveform of current through a special IC. Fig. 9C shows that alternating-current preheating of the energy supply device 100 is achieved by repeatedly flowing a preset current into and out of the energy supply device 100 by a bidirectional AC-DC converter. Since the bidirectional AC-DC converter is used, a rectifying unit is not required, alternating current of the utility power is converted into direct current by the bidirectional AC-DC converter and flows into the energy supply device 100, and direct current flowing out of the energy supply device 100 can be converted into alternating current by the bidirectional AC-DC converter and flows back to the utility power. The above bi-directional DC-DC converter and the bi-directional AC-DC converter are both bi-directional converters.

Fig. 10 to 12 illustrate another preheating method for the power supply device 100 according to the embodiment of the present invention. As an embodiment, the energy supply device 100 includes at least a first battery B1 and a second battery B2, wherein the first battery B1 includes at least one battery cell 103, and the second battery B2 includes at least one battery cell 103. The first battery B1 and the second battery B2 serve as battery management subunits, which facilitate detection and management of the energy supply device 100, and the connection mode is not limited in the application, and the first battery B1 and the second battery B2 may be connected in series or in parallel. The preheating control module 300 is configured to control the first battery B1 and the second battery B2 to alternately charge and discharge when the temperature of the energy supply device 100 is lower than a first preset temperature until the temperature of the energy supply device 100 is greater than or equal to a second preset temperature. In a specific embodiment, the preheating control module 300 further includes a voltage acquisition unit 342, a fourth control unit 341, a seventh transistor M7, an eighth transistor M8, and a fourth energy storage device; the fourth control unit 341 is configured to, when the temperature of the energy supply device 100 is lower than a first preset temperature, sequentially and circularly control the first battery B1 and the second battery B2 to alternately charge and discharge by controlling the on or off of the seventh transistor M7 and/or the eighth transistor M8 at a certain time interval until the temperature of the energy supply device 100 is greater than or equal to a second preset temperature.

The fourth control unit 341 may be a single chip microcomputer. The fourth energy storage means is a second inductive element L2. The preheating control module 300 further includes a fifth resistor R5, a sixth resistor R6, a fifth diode D5, and a sixth diode D6. The fifth resistor R5 and the sixth resistor R6 are used for voltage division and current limiting, and the fifth diode D5 and the sixth diode D6 are used for anti-reflection. The fourth control unit 341, the seventh transistor M7, the eighth transistor M8, the second inductive element L2, the first battery B1, the second battery B2, the fifth resistor R5, the sixth resistor R6, the fifth diode D5, and the sixth diode D6 may be integrated in the power supply device 100, that is, the preheating control module 300 is disposed in the housing 101 of the power supply device 100. As one embodiment, the power supply device 100 includes a power management board 110, and a fourth control unit 341, a seventh transistor M7, an eighth transistor M8, a second inductive element L2, a first battery B1, a second battery B2, a fifth resistor R5, a sixth resistor R6, a fifth diode D5, and a sixth diode D6 are disposed on the power management board 110. The voltage equalization circuit of the energy supply device 100 is multiplexed in the embodiment, and the voltage among the battery packs can be consistent while the low-temperature preheating function of the energy supply device 100 is provided, so that the power supply time and the service life of the energy supply device 100 are improved; furthermore, the energy supply device 100 provided with the voltage equalizing circuit is low in modification cost.

The temperature detection module 200 is configured to detect a temperature of the energy supply device 100, and in an embodiment, the temperature detection module 200 detects temperatures of the first battery B1 and the second battery B2 and sends the detected temperatures to the fourth control unit 341. In another embodiment, the temperature detection module 200 detects the temperature of other components inside the power supply device 100, for example, the power management board 110, and sends the detected temperature to the fourth control unit 341. The voltage acquisition unit 342 acquires the voltages of the first battery B1 and the second battery B2, and transmits the voltages to the fourth control unit 341. When the temperature of the power supply device 100 is lower than the first preset temperature, the fourth control unit 341 starts ac preheating of the power supply device 100. The fourth control unit 341 first compares the voltages of the first battery B1 and the second battery B2, and if the voltage of the first battery B1 is higher than the voltage of the second battery B2, the fourth control unit 341 controls the seventh transistor M7 to be turned on and the eighth transistor M8 to be turned off, so that the first battery B1 is discharged to charge the fourth energy storage device; after the first battery B1 discharges for the third preset time interval, the fourth control unit 341 controls the seventh transistor M7 to be turned off and the eighth transistor M8 to be turned on, so that the fourth energy storage device discharges to charge the second battery B2. Otherwise, the fourth control unit 341 controls the seventh transistor M7 to be turned off and the eighth transistor M8 to be turned on, so that the second battery B2 is discharged to charge the fourth energy storage device; after the second battery B2 is discharged for the third preset time interval, the fourth control unit 341 controls the seventh transistor M7 to be turned on and the eighth transistor M8 to be turned off, so that the fourth energy storage device is discharged to charge the first battery B1.

When the fourth energy storage device discharges and reaches the fourth preset time interval, comparing the voltages of the first battery B1 and the second battery B2 again, and if the voltage of the first battery B1 is still higher than the voltage of the second battery B2 at this time, the fourth control unit 341 controls the seventh transistor M7 to be turned on and the eighth transistor M8 to be turned off so that the first battery B1 discharges and charges the fourth energy storage device, and controls the seventh transistor M7 to be turned off and the eighth transistor M8 to be turned on so that the fourth energy storage device discharges and charges the second battery B2; otherwise, the seventh transistor M7 is controlled to be turned off and the eighth transistor M8 is controlled to be turned on, so that the second battery B2 is discharged to charge the fourth energy storage device, and then the seventh transistor M7 is controlled to be turned on and the eighth transistor M8 is controlled to be turned off, so that the fourth energy storage device is discharged to charge the first battery B1. In this way, the ac preheating of the power supply device 100 is realized, and when the temperature of the power supply device 100 is greater than or equal to the second preset temperature, the ac preheating of the power supply device 100 is stopped. Alternatively, when the current flows out of the first battery B1, the voltage drop slope of the first battery B1 is less than or equal to the first preset slope, and when the current flows out of the second battery B2, the voltage drop slope of the second battery B2 is also less than or equal to the first preset slope, the preheating control module 300 may stop preheating the energy supply device 100.

In the ac preheating process, the fourth energy storage device serves as a temporary energy storage device, so that current repeatedly flows in and out from the first battery B1 and the second battery B2, thereby achieving the function of the heating energy supply device 100. The specific charge-discharge sequence is adjusted in real time by the fourth control unit 341 according to the voltages of the first battery B1 and the second battery B2, so that the battery with higher voltage discharges and the battery with lower voltage charges, thereby balancing the voltages of the first battery B1 and the second battery B2 while heating the energy supply device 100, and improving the power supply time and the service life of the energy supply device 100. It is understood that the energy supply device 100 may include more battery packs such as a third battery pack and a fourth battery pack, and may also include more temporary energy storage devices, and the fourth control unit 341 may control one or more battery packs to discharge simultaneously, and may control one or more battery packs to charge simultaneously according to the voltage of each battery pack, which is not limited herein.

The first preset time interval, the second preset time interval, the third preset time interval and the fourth preset time interval may be set according to actual situations, and are not limited herein. In addition, the condition that the warm-up control module 300 exits the warm-up mode is not limited to the temperature of the power supply device 100 being greater than or equal to the second preset temperature. For example, the voltage drop slope (voltage change per unit time) may also be used as an consideration parameter for exiting the warm-up mode. Specifically, when the current flows out of the energy supply device 100, the preheating control module 300 may stop preheating the energy supply device 100 when the voltage drop slope of the energy supply device 100 is equal to or less than the first preset slope.

Referring to fig. 13 and 14A to 14D, another preheating method of the power supply device 100 for the electric tool 600 according to the embodiment of the present invention is provided. The power supply device 100 includes at least a first battery C1 and a second battery C2. The first battery C1 includes at least one cell, and the second battery C2 includes at least one cell. In an embodiment, the first battery C1 and the second battery C2 are independent battery packs, respectively; in another embodiment, the first battery C1 and the second battery C2 are independent battery cell modules. The power tool 600 may be a multi-pack power tool, or a power tool with a built-in battery module, and the power tool 600 further includes a housing and a motor. Similar to the previous embodiments, the temperature detection module 200 may be disposed within the power supply 100 or on the power tool 600. In the present embodiment, the preheating control module 300 includes a fifth control unit 1311, a preheating mode switching switch S5, an inverter circuit 1312, and a motor winding 1313. In this embodiment, the motor used in the electric tool 600 is a three-phase motor, the inverter circuit 1312 is a driving circuit of the motor, and the inverter circuit 1312 includes upper bridge switches V1, V3, and V5 and lower bridge switches V2, V4, and V6; the motor winding 1313 includes A, B, C three phases. The motor winding a is connected to first bridges (V1, V2) of the inverter circuit 1312; the motor winding B is connected to the second bridge (V3, V4) of the inverter circuit 1312; the motor winding C is connected to third bridges (V5, V6) of the inverter circuit 1312. Optionally, the fifth control unit 1311 is electrically connected to the power-on unit 410 of the electric tool 600, when the electric tool 600 needs to be started, the fifth control unit 1311 receives the first signal sent by the power-on unit 410, and then, the fifth control unit 1311 obtains the temperature of the energy supply device 100 through the temperature detection module 200 and determines the temperature, when the temperature of the energy supply device 100 is greater than or equal to the first preset temperature, allows the electric tool 600 to directly enter the power-on/standby state, and when the temperature of the energy supply device 100 is lower than the first preset temperature, preheats the energy supply device 100.

A warm-up mode changeover switch S5 is provided between the first battery pack C1 and the second battery pack C2 for switching the warm-up mode to the power supply device 100. The fifth control unit 1311 is electrically connected to the temperature detection module 200, the preheating mode switch S5, and the inverter circuit 1312, and is configured to control the preheating mode switch S5 and the inverter circuit 1312 to sequentially and circularly control the transfer of the preset current between the first battery pack C1, the second battery pack C2, and the motor winding at a certain time interval until the temperature of the energy supply device 100 is greater than or equal to the second preset temperature, or the voltage drop slope of the energy supply device 100 is less than or equal to the first preset slope when the temperature of the energy supply device 100 is lower than the first preset temperature. Of course, the preheating control module 300 may not include the preheating mode switching switch S5 and use a single preheating mode. When the preheating mode switch S5 is closed, the first battery C1 and the second battery C2 are connected in parallel, and the preheating mode of the energy supply device 100 is similar to that shown in fig. 3 and fig. 4A to 4D, and will not be repeated here; when the warm-up mode changeover switch S5 is turned off, the first bridge (V1, V2) of the inverter circuit 1312 is connected to the first battery group C1, and the remaining bridges (V3, V4, V5, V6) are connected to the second battery group C2. The warm-up process when the warm-up mode changeover switch S5 is turned off is described in detail below with reference to fig. 14A to 14D. Fig. 14A is a schematic circuit diagram of a first current loop Q1 of the circuit shown in fig. 13, fig. 14B is a schematic circuit diagram of a second current loop Q2 of the circuit shown in fig. 13, fig. 14C is a schematic circuit diagram of a third current loop Q3 of the circuit shown in fig. 13, and fig. 14D is a schematic circuit diagram Q4 of a fourth current loop of the circuit shown in fig. 13.

Illustratively, in a first stage of the warm-up process, the fifth control unit 1311 controls the inverter circuit 1312 to switch between a first current loop Q1 and a second current loop Q2, wherein the first current loop Q1 dominates. In the first current loop Q1, the fifth control unit 1311 controls the upper bridge switch V1 and the lower bridge switches V4 and V6 of the inverter circuit 1312 to be opened so that current flows out from the first battery group C1, back to the first battery group C1 via the motor windings A, B and C. In the second current loop Q2, the fifth control unit 1311 controls the upper bridge switches V1, V3, and V5 of the inverter circuit 1312 to open so that current flows from the first battery group C1, through the motor windings A, B and C, and into the second battery group C2. In the second stage of the warm-up process, the fifth control unit 1311 controls the inverter circuit 1312 to form the second current loop Q2 such that electric power is transferred from the first battery pack C1 to the second battery pack C2. In a third phase of the preheating process, the fifth control unit 1311 controls the inverter circuit 1312 to switch between a third current loop Q3 and a fourth current loop Q4, wherein the third current loop Q3 dominates. In the third current loop Q3, the fifth control unit 1311 controls the lower bridge switch V2 and the upper bridge switches V3 and V5 of the inverter circuit 1312 to be opened so that current flows from the second battery group C2, back to the second battery group C2 via the motor windings B, C and a. In the fourth current loop Q4, the fifth control unit 1311 controls the upper bridge switches V1, V3, and V5 of the inverter circuit 1312 to open so that current flows from the second battery group C2, through the motor windings B, C and a, and into the first battery group C1. In the fourth stage of the warm-up process, the fifth control unit 1311 controls the inverter circuit 1312 to form the fourth current loop Q4 such that electric power is transferred from the second battery pack C2 to the second battery pack C1.

The first to fourth stages are cycled according to a certain time interval, so that the first, second, third and fourth current loops Q1, Q2, Q3 and Q4 can be charged and discharged according to a preset current, and electric energy is transferred back and forth between the first and second battery packs C1 and C2 via the motor winding 1313, thereby realizing slow heating of the energy supply device 100 in a low-temperature environment without causing burnout due to instantaneous large current. The time intervals of switching in each stage can be set according to actual conditions, and can be equal or unequal, and the time intervals are not particularly limited; the value of the preset current may be set according to the actual situation, and is not particularly limited herein.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims (12)

1. A power tool powered using an energy supply, the power tool comprising:

a housing formed with a receiving chamber;

the first energy storage device and the second energy storage device are arranged in the shell;

the driving circuit is arranged in the shell;

a first control unit electrically connectable to a temperature detection module of the energy supply device to obtain a temperature of the energy supply device;

the energy supply device is characterized in that when the temperature of the energy supply device is lower than a first preset temperature, the first control unit controls the on or off state of the driving circuit, and sequentially and circularly controls preset current to flow into the first energy storage device and the second energy storage device from the energy supply device and flow into the energy supply device from the second energy storage device and the first energy storage device until the temperature of the energy supply device is higher than or equal to a second preset temperature or the voltage drop slope of the energy supply device is lower than or equal to a first preset slope.

2. The power tool of claim 1, further comprising a motor housed within the housing, the motor including a winding, the first energy storage device being the winding.

3. The power tool of claim 1, wherein the second energy storage device is a capacitive element, the second energy storage device being in parallel with the drive circuit.

4. The power tool of claim 2, wherein the drive circuit multiplexes the drive circuit of the motor, comprising an upper bridge comprising at least two transistors and a lower bridge comprising at least two transistors.

5. The power tool according to claim 4, wherein the first control unit turns on or off both transistors of the upper bridge simultaneously; the first control unit synchronously turns on or off the two transistors of the lower bridge.

6. The power tool according to claim 1, further comprising a first switch provided between the energy supply device and the drive circuit for turning on or off power supply of the drive circuit by the energy supply device; when the temperature of the energy supply device is lower than the first preset temperature, the first control unit controls the first switch to be closed.

7. The power tool according to claim 2, wherein the driving circuit includes a first transistor, a second transistor, a third transistor, and a fourth transistor; the first control unit controls the first transistor and the second transistor to be closed, so that the energy supply device, the first energy storage device, the first transistor and the second transistor form a first current loop, and current flows into the first energy storage device from the energy supply device; forming a second current loop by controlling the first transistor and the second transistor to be disconnected, so that current flows from the energy supply device to the second energy storage device; forming a third current loop by controlling the third transistor and the fourth transistor to be closed, so that current flows from the second energy storage device to the energy supply device; and controlling the third transistor and the fourth transistor to be disconnected, so that the first energy storage device, the energy supply device, the first transistor and the second transistor form a fourth current loop, and current flows from the first energy storage device to the energy supply device.

8. The power tool according to claim 1, further comprising a power-on unit for transmitting a first signal to the first control unit, the first control unit controlling the driving circuit to heat the energy supply device when the first signal is received and the temperature of the energy supply device is lower than the first preset temperature.

9. The power tool of claim 8, further comprising a wireless communication interface for communicatively connecting the power tool to a remote device, the first signal being sent to the first control unit when the power-on unit receives a standby command sent by the remote device.

10. The power tool according to claim 6, further comprising a fault detection unit that detects a current of the first energy storage device, the first control unit making a fault determination by comparing the detected current with the preset current, and controlling the first switch to be turned off when it is determined that a fault occurs.

11. An electric tool powered using an energy supply device, the energy supply device comprising a first battery pack and a second battery pack, the electric tool comprising:

A housing;

a motor comprising a winding;

an inverter circuit comprising a plurality of switches;

a control unit configured to be electrically connected with the temperature detection module to acquire a temperature of the energy supply device;

the control unit is characterized in that when the temperature of the energy supply device is lower than a first preset temperature, the control unit controls the switches to be turned on or off so that electric energy is transferred between the first battery pack and the second battery pack through the windings until the temperature of the energy supply device is higher than or equal to a second preset temperature or the voltage drop slope of the energy supply device is lower than or equal to a first preset slope.

12. The power tool of claim 11, further comprising a preheat mode switch, the first battery pack being electrically connected to a portion of the switches of the plurality of switches and the second battery pack being electrically connected to a remaining portion of the switches of the plurality of switches when the preheat mode switch is open.

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