CN112803506A - Electric tool - Google Patents
Electric tool Download PDFInfo
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- CN112803506A CN112803506A CN201911030910.3A CN201911030910A CN112803506A CN 112803506 A CN112803506 A CN 112803506A CN 201911030910 A CN201911030910 A CN 201911030910A CN 112803506 A CN112803506 A CN 112803506A
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- 238000012544 monitoring process Methods 0.000 claims abstract description 4
- 238000001514 detection method Methods 0.000 claims description 23
- 230000002159 abnormal effect Effects 0.000 description 4
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- 230000002035 prolonged effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 244000025254 Cannabis sativa Species 0.000 description 1
- 241001417527 Pempheridae Species 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Secondary Cells (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention discloses an electric tool, comprising: a motor; a first battery pack and a second battery pack for supplying electric energy to the motor; the first switch device and the second switch device are correspondingly connected in series between the first battery pack and the motor and between the second battery pack and the motor one by one so as to switch on or switch off the connection between the first battery pack and the motor and the connection between the second battery pack and the motor; and the controller is used for monitoring the mutual charging current between the first battery pack and the second battery pack and controlling the corresponding switching device to cut off the connection between the battery pack with relatively low voltage and the motor when the mutual charging current is greater than the safety current threshold value. This electric tool can break off the battery package of low pressure side when mutual charging current is greater than safe electric current, avoids mutual charging current to surpass safe electric current and cause the battery damage, effectively avoids the security risk, guarantees the security and the reliability of battery package, effectively guarantees electric tool's life.
Description
Technical Field
The invention relates to the technical field of battery power supply, in particular to an electric tool.
Background
At present, for a high-power electric tool, parallel connection of a plurality of battery packs is one of power supply modes, and the plurality of battery packs are connected in parallel, although the battery endurance, the power and the service life of the battery are greatly improved due to the parallel connection of the plurality of battery packs, the voltages among the battery packs cannot be completely the same, so that potential difference is formed among the plurality of battery packs, and current is formed, flows from a high-potential battery pack to a low-potential battery pack, charges the low-potential battery pack and forms mutual charging current.
In the related art, if the temperature of the battery pack is detected to be between 0 ℃ and 45 ℃, the battery packs are allowed to be charged with each other. Once the mutual charging current is not controlled, especially when the differential pressure of a plurality of battery packs of the tool is greater than a certain value, the mutual charging current may exceed the safe current of the battery, and the battery has certain safety risk, which easily causes the battery to be damaged, reduces the service life of the battery, and needs to be solved urgently.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, an object of the present invention is to provide an electric tool, which can disconnect a battery pack on a low-voltage side when a mutual charging current is larger than a safety current, so as to prevent damage to a battery caused by the mutual charging current exceeding the safety current.
In order to achieve the above object, an embodiment of the present invention provides an electric power tool, including: a motor; a first battery pack and a second battery pack for providing the motor with electric energy; the first switch device is connected between the first battery pack and the motor in series to switch on or off the connection between the first battery pack and the motor, and the second switch device is connected between the second battery pack and the motor in series to switch on or off the connection between the second battery pack and the motor; and the controller is used for monitoring the mutual charging current between the first battery pack and the second battery pack and controlling the corresponding switching device to cut off the connection between the battery pack with relatively low voltage and the motor when the mutual charging current is greater than a safe current threshold value.
According to the electric tool provided by the embodiment of the invention, the first battery pack and the second battery pack are connected in parallel to provide electric energy for the motor, when the charging current between the first battery pack and the second battery pack is greater than the safety current, the battery packs at the low-voltage side are disconnected, the damage to the battery caused by the fact that the mutual charging current exceeds the safety current is avoided, the safety risk is reduced and even effectively avoided, the battery duration, the power and the service life of the battery are improved by ensuring the parallel connection of a plurality of packs, the safety and the reliability of the battery packs are ensured, the service life of the battery is greatly prolonged, the service life of the electric tool is effectively ensured, and the applicability and the use experience of the tool are improved.
In addition, the electric tool according to the above embodiment of the present invention may further have the following additional technical features:
further, in an embodiment of the present invention, the control unit further includes a current detection unit, configured to detect a magnitude and a direction of a mutual charging current between the first battery pack and the second battery pack, where the battery pack with the relatively low voltage is a battery pack to which the mutual charging current flows.
Further, in an embodiment of the present invention, the control unit further includes a voltage detection module, configured to detect voltages of the first battery pack and the second battery pack, and control the corresponding switch device to disconnect the battery pack with a relatively low voltage from the motor when the mutual charging current is greater than a safety current threshold.
Further, in one embodiment of the present invention, the controller includes: the voltage detection unit is used for detecting a first current voltage of a battery pack in a power supply state in the first battery pack and the second battery pack; the temperature detection module is used for detecting a first current temperature of a battery pack in a power supply state in the first battery pack and the second battery pack; and the control unit is used for controlling the corresponding switch device to cut off the connection between the battery pack which does not meet the power supply condition and the motor when the first current temperature or the first current voltage does not meet the power supply condition.
Further, in an embodiment of the present invention, the temperature detecting unit and the voltage detecting unit are further configured to detect a second current temperature and a second current voltage of a battery pack in an idle state in the first battery pack and the second battery pack, and when both the second current temperature and the second current voltage satisfy the power supply condition, the control unit controls the corresponding switch device to connect the battery pack that satisfies the power supply condition to the motor, and the first battery pack and the second battery pack are connected in parallel to provide electric energy for the motor.
Further, in an embodiment of the present invention, the controller is further configured to receive a power-on command of the power tool, and close the first and second switching devices when the current temperature and the current voltage of the first and second battery packs satisfy the power supply condition.
Further, in one embodiment of the present invention, the first switching device and the second switching device respectively include: the power supply device comprises a power-on loop and a power switch device, wherein the power-on loop and the power switch device are both arranged between a battery pack and the motor and are connected in parallel.
In addition, in one embodiment of the present invention, the method further includes: the battery pack comprises a first battery accommodating part and a second battery accommodating part, wherein the first battery accommodating part and the second battery accommodating part are used for accommodating and connecting the first battery pack and the second battery pack in a one-to-one correspondence manner.
Alternatively, in one embodiment of the invention, the power tool may be a lawn mower comprising a body on which the first and second battery packs are disposed side by side.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic structural view of a power tool according to an embodiment of the present invention.
Fig. 2 is a block diagram of a power tool according to an embodiment of the present invention.
Fig. 3 is a flowchart of a control method of the electric tool according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a proposed electric power tool according to an embodiment of the present invention with reference to the accompanying drawings.
Fig. 1 is a schematic structural view of a power tool according to an embodiment of the present invention.
As shown in fig. 1, the electric power tool of the embodiment of the present invention includes: motor 100, n battery packs (shown as battery pack 201, battery packs 202, …, and battery pack 20 n), a switching device (shown as switching device 301, switching devices 302, …, and switching device 30 n) connected in series with the n battery packs, and a controller 400. Wherein n battery packs are connected in parallel for providing electrical energy to the motor 100. The n switching devices are connected in series between the n battery packs and the motor 100 in a one-to-one correspondence manner to connect or disconnect the n battery packs and the motor 100, wherein n is a positive integer greater than 1.
According to the invention, a plurality of battery packs are connected in parallel, a closed loop is formed among the plurality of battery packs, when the voltages of the plurality of battery packs are different, the risk of cross charging exists in the loop formed among the plurality of battery packs, namely, the battery pack with high voltage charges the battery pack with low voltage, the controller 400 is used for monitoring cross charging current, namely, mutual charging current, between any two battery packs in the plurality of battery packs connected in parallel, and controlling the corresponding switch device to cut off the connection between the battery pack with relatively low voltage in any two battery packs and the motor 100 when the mutual charging current is greater than a safety current threshold value. The electric tool provided by the embodiment of the invention can disconnect the battery pack at the low-voltage side when the mutual charging current is greater than the safety current, so that the battery damage caused by the fact that the mutual charging current exceeds the safety current is avoided, the safety risk is effectively avoided, the safety and the reliability of the battery pack are ensured, and the service life of the electric tool is effectively ensured.
Specifically, two battery packs are taken as an example for explanation, and please refer to fig. 2, which is a schematic diagram of a dual-pack control circuit of the present invention, in an embodiment of the present invention, the two battery packs are a first battery pack 201 and a second battery pack 202, the first battery pack 201 and the second battery pack 202 form a parallel circuit for providing power for the motor 100, and the controller 400 is disposed between the parallel circuit and the motor 100 for controlling the rotation and stop of the motor. The first switching device 301 is connected in series between the first battery pack 201 and the controller 400 for switching off the connection between the first battery pack 201 and the motor 100, and the second switching device 302 is connected in series between the second battery pack 202 and the controller 400 for switching on or off the connection between the second battery pack 202 and the motor 100. The controller 400 is configured to monitor the magnitude of the mutual charging current in a loop formed by the first battery pack 201, the first switch device 301, the second battery pack 202, and the second switch device 302, and when the mutual charging current is greater than the safety current threshold, the controller 400 controls the switch device corresponding to the battery pack with relatively low voltage to be turned off, so that the battery pack with relatively high voltage alone provides electric energy for the motor 100. When the mutual charging current is larger than the safe current threshold value, the battery pack at the low-voltage side is disconnected, the damage to the battery caused by the fact that the mutual charging current exceeds the safe current is avoided, the safety risk is effectively avoided, the safety and the reliability of the battery pack are ensured, and the service life of the electric tool is effectively ensured.
In the embodiment of the invention, two battery packs are connected in parallel, which belongs to a short circuit and is easy to generate cross charging. If the internal resistance of both battery packs were to approach zero, the crossover current would be infinite, resulting in burning out the battery. The actual cell internal resistance will of course not be zero, but the cross-charge current will also be large. The current direction is from the higher voltage power source (discharging direction) and flows back to the lower voltage power source (charging direction). Therefore, the embodiment of the present invention further detects the voltage of the battery pack, and there are many detection methods, for example, the voltage detection module may detect the voltage, or the current detection unit 4011 may detect the voltage, and the following describes the schemes of the voltage detection module and the current detection unit 4011 in detail.
In one embodiment of the present invention, the controller 400 includes a current detecting unit 4011 for detecting the magnitude and direction of the mutual charging current between the first battery pack 201 and the second battery pack 202, that is, the current detecting unit 4011 detects whether there is a negative current flowing to the first battery pack 201 through the first switching device 301 to charge the first battery pack 201, or the current detecting unit 4011 detects whether there is a negative current flowing to the second battery pack 202 through the second switching device 302 to charge the second battery pack 202, when the current detecting unit 4011 detects the mutual charging current flowing to the first battery pack 201 through the first switching device 301, that is, the negative current flowing to the first battery pack 201, the magnitude of the mutual charging current is obtained, and whether the mutual charging current is greater than a safety current threshold value is determined, if the mutual charging current is greater than the safety current threshold value, it is determined that the voltage of the first battery pack 201 is lower relative to the voltage of the second battery pack 202, the controller 400 controls the first switching device 301 to be turned off, the first battery pack 201 stops supplying power to the motor 100, and only the second battery pack 202 having a relatively high voltage supplies power to the motor 100. Similarly, when the current detecting unit 4011 detects the mutual charging current flowing to the second battery pack 202 through the second switch device 302, that is, the negative current flowing to the second battery pack 202, the magnitude of the mutual charging current is obtained, and when the mutual charging current is greater than the safety current threshold, which indicates that the voltage of the second battery pack 202 is lower relative to the voltage of the first battery pack 201, the controller 400 controls the second switch device 302 to be turned off, the second battery pack 202 stops supplying power to the motor 100, and only the first battery pack 201 with the relatively higher voltage supplies power to the motor 100.
In another embodiment of the present invention, the controller 400 includes a voltage detection module and a current detection unit 4011, the voltage detection unit 4011 is configured to detect voltages of the first battery pack 201 and the second battery pack 202, the current detection unit 4011 is configured to detect a magnitude of a mutual charging current in a parallel circuit formed by the first battery pack 201 and the second battery pack 202, when the mutual charging current is greater than a safety current threshold, if a voltage of the first battery pack 201 is greater than a voltage of the second battery pack 202 at this time, the controller 400 controls the second switching device 302 to be turned off, the second battery pack 202 stops providing power to the motor 100, and only the first battery pack 201 provides power to the motor 100.
Although the above-mentioned embodiment takes the first battery pack 201 and the second battery pack 202 as an example, it should be understood by those skilled in the art that any electric tool in fig. 1 can be configured in a similar manner, and it should be noted that the connection manner between the plurality of battery packs in fig. 1 is only illustrative, and the present invention is not limited to this connection manner.
It should be noted that, although the parallel connection of the multiple packs can improve the cruising ability, the power and the service life of the battery, once the mutual charging current is not controlled, the battery is easily damaged, and the service life of the battery is reduced, therefore, in the embodiment of the present invention, the mutual charging current between the two parallel-connected battery packs is detected in real time, the mutual charging current is judged, whether the mutual charging current is greater than the safety current threshold value is judged, and whether the single battery pack provides the electric energy for the motor or the two parallel-connected battery packs provide the electric energy for the motor is controlled according to the judgment result.
The safety current threshold value may be set by a person skilled in the art according to actual conditions, preferably, the safety threshold value cannot be higher than the maximum charging current of the battery pack set by the battery pack manufacturer, and it should be noted that the larger the safety current threshold value is, the larger the upper limit of the mutual charging current is, the faster the temperature of the battery pack rises, and the higher the requirement on the safety of the battery is.
That is to say, the embodiment of the invention aims to solve the problem how to control the mutual charging current, avoid exceeding the safe current, disconnect the battery pack at the low-voltage side and stop the power supply of the battery pack at the low-voltage side to the tool, so that when a plurality of packs of tools are used in parallel, the safety risk of the large-current mutual charging of the battery packs can be effectively reduced, the safety and the reliability of the battery packs are ensured, and the service life of the battery is greatly prolonged.
In another embodiment of the present invention, please refer to fig. 1, the controller 400 includes: a detection unit 401 and a control unit 402. The detection unit 401 may specifically include a temperature sensor and a voltage detection module. The temperature sensor is configured to detect a first current temperature of one of the first battery pack 201 and the second battery pack 202 in a power supply state, and the voltage detection module is configured to detect a first current voltage of one of the first battery pack 201 and the second battery pack 202 in the power supply state. The control unit 402 is configured to control the corresponding switch device to disconnect the battery pack that does not satisfy the power supply condition from the motor when the first current temperature or the first current voltage does not satisfy the power supply condition.
It can be understood that, in the embodiment of the present invention, the state parameters, such as the temperature, the voltage, and the like, of the battery pack in the power supply state are detected to determine whether the battery pack has a fault, for example, if the temperature of the battery pack is greater than a predetermined value, or the voltage is greater than a predetermined value, it indicates that the battery is abnormal and is not suitable for continuing power supply, that is, the power supply condition is not satisfied, the power supply to the tool is stopped, which not only avoids the damage to the battery, but also avoids the influence on other batteries, even the damage to the tool. It should be noted that the power supply condition can be set by a person skilled in the art according to practical situations, and is not limited specifically herein.
In addition, in an embodiment of the invention, the temperature sensor is further configured to detect a second current temperature of the battery pack in the idle state, and the voltage detection module is configured to detect a second current voltage of the battery pack in the idle state. And when the second current temperature and the second current voltage both satisfy the power supply condition, the control unit 402 controls the corresponding switching device to turn on the connection between the battery pack satisfying the power supply condition and the motor 100.
That is, in the embodiment of the present invention, for a battery pack that was previously disconnected due to a low voltage, that is, a battery pack in an idle state, the embodiment of the present invention may detect parameters such as a voltage and a temperature of the battery pack. If the temperature and the voltage of the battery pack in the idle state are in the set range, the battery pack in the idle state has the condition of accessing the power supply loop to continue supplying power, and the battery pack can be accessed into the power supply loop to be connected with other battery packs in parallel to supply power for the tool; and otherwise, after the battery pack in the idle state is disconnected with the power supply loop, the high-voltage battery pack supplies power until the tool is turned on and off again.
In addition, if parameters such as voltage and temperature of a battery pack disconnected due to a failure, that is, a battery pack in an abnormal state satisfy power supply conditions set by those skilled in the art, the power supply circuit may be reconnected.
Further, in an embodiment of the present invention, the controller 400 is further configured to disconnect the direct connection of the remaining battery pack 100 if the first battery pack 201 or the second battery pack 202 supplying power alone does not satisfy the power supply condition when the first battery pack 201 alone supplies power to the motor 100 or the second battery pack 202 alone supplies power to the motor 100.
Specifically, when the number of battery packs supplying power is smaller than a certain value, for example, only one battery pack supplies power to a single battery pack, once the parameters of the voltage, the temperature and the like of the battery pack supplying power are not within a predetermined range, the last battery pack is not suitable for continuing supplying power, so that power supply is stopped, damage to the battery and even damage to a tool are avoided, and corresponding fault reminding can be performed, for example, an acoustic reminding device and/or an optical reminding device is controlled to perform fault reminding, so that the use experience of a user is improved.
It can be understood that, in the operation process, the embodiment of the present invention continuously monitors the voltage, the temperature, and other parameters of the battery pack, and if the voltage, the temperature, and other parameters of any one battery pack exceed the predetermined range, if the power is supplied by a single pack at this time, the tool enters the protection mode, and stops supplying power, and if the power is supplied by multiple packs at this time, the overrun battery pack is disconnected from the power supply loop. It should be noted that, the tool enters the protection mode, and the protection mode may be for stopping power supply, and may also include other corresponding control strategies, such as re-screening the battery pack in the idle state, accessing the battery pack in the idle state meeting the power supply condition to the power supply loop, and disconnecting the single power supply pack, so as to effectively ensure the safety of the battery and the tool, which is not limited herein.
Further, in an embodiment of the present invention, the controller 400 is further configured to receive a power-on command, as shown in fig. 2, when the trigger switch 700 is closed, and after the controller 400 receives the power-on command, the controller 400 determines whether the current temperature and the current voltage of the first battery pack 201 and the second battery pack 202 satisfy the power supply condition, and if so, closes the first switch device 301 and the second switch device 302. If it is detected that the current temperature or the current voltage of the first battery pack 201 does not satisfy the power supply condition, and the current temperature or the current voltage of the second battery pack 201 satisfies the power supply condition, the controller 400 controls the first switching device 301 to be in the open state, and the second switching device 301 to be closed.
That is to say, when the tool is started, the battery packs meeting the power supply condition are all connected into the power supply loop, when the battery packs are connected in parallel, if the mutual charging current is larger than the set threshold value, the low-voltage battery pack is disconnected from the power supply loop, the high-voltage battery pack continues to supply power until the tool is restarted, and if the mutual charging current is smaller than the set threshold value, the low-voltage battery pack can be freely charged.
Further, in one embodiment of the present invention, the electric power tool of the embodiment of the present invention further includes: a feedback module 500 and a drive module 600. The feedback module 500 is configured to feedback the current operating parameter of the load. When the current operating parameter does not satisfy the disconnection control condition, the controller 400 controls the driving module 600 to lower the current operating parameter of the load or to disconnect the battery pack from the motor 100.
It can be understood that the embodiment of the present invention can read the feedback parameters of the voltage, the current, the rotation speed, and the like of the motor, and once the current operating parameters do not satisfy the disconnection control conditions, such as the power supply of a single battery cannot satisfy the requirement of the load, which means that the battery pack on the low voltage side cannot be disconnected, the load is reduced or the power supply is stopped, and then the battery pack on the low voltage side is disconnected, so as to ensure the safety and the reliability of the battery, and avoid the occurrence of safety accidents.
Further, in one embodiment of the present invention, each of the first switching device 301 and the second switching device 302 includes: a power-up loop (shown as power-up loop 3011, power-up loops 3021, …, and power-up loop 30n 1) and a power switch (shown as power switch 3012, power switches 3022, …, and power switch 30n 2). The power-up loop and the power switch device are both arranged between the battery pack and the motor 100, and are connected in parallel.
The following sections of embodiments of the present invention will describe in detail how the battery-powered control is controlled. Although the following embodiments exemplify controlling the closing and turning off of the power switch device to realize multi-pack parallel connection, it should be understood by those skilled in the art that any battery in fig. 1 can be configured in a similar manner, i.e., the connection and configuration of the battery pack and the control power switch device are only illustrative, and the present invention is not limited to this connection and configuration.
As shown in fig. 1, the switching device includes an upper circuit and a power switching device corresponding to each battery pack, and in the embodiment of the present invention, the power switching device may be turned on and off to implement multi-pack parallel connection, so as to control the mutual charging current in a relatively safe range.
Specifically, referring to fig. 3, in an embodiment of the present invention, the electric tool of the embodiment of the present invention may perform the following steps:
step S10: the first and second switching devices are closed. In one embodiment of the invention, before the first switch device and the second switch device are closed, battery parameters such as temperature, voltage and the like of the first battery pack and the second battery pack are obtained, if the temperature and the voltage of the first battery pack and the second battery pack are both in a set range, the first switch device and the second switch device are closed, and the first battery pack and the second battery pack are connected in parallel to provide electric energy for the motor. If the voltage or the temperature of the first battery pack is not within the preset range any more, the first switch device is in an off state, the second switch device is turned on, the second battery pack provides electric energy for the motor, the voltage and the temperature of the first battery pack are detected in real time, and if the voltage and the temperature of the first battery pack are within the preset range after a period of time, the first switch device is controlled to be turned on.
Step S20: and detecting the mutual charging current between the first battery pack and the second battery pack. The first battery pack and the second battery pack are connected in parallel, if the voltages of the first battery pack and the second battery pack are different, the high-voltage battery pack can charge the low-voltage battery pack, namely, mutual charging current can exist between the first battery pack and the second battery pack, the controller detects whether cross charging current exists, if so, the controller obtains the size of the cross charging current, and meanwhile, the size relation between the cross charging current, namely the mutual charging current, and a safety current threshold value is judged.
Step S30: and if the mutual charging current is larger than the safe current threshold, controlling the switch device corresponding to the battery pack with relatively low voltage to be switched off. In the invention, if the controller detects that the mutual charging current is greater than the safe current threshold, the voltage difference between the first battery pack and the second battery pack is larger, and the mutual charging current is larger, so that the battery pack is broken down, and the service life of the battery pack is influenced. Therefore, if the mutual charging current of the battery pack with lower voltage is larger than the safe current threshold value in the two battery packs connected in parallel, the battery pack with lower voltage is disconnected from the power supply loop and is powered by the battery pack with higher voltage until the power supply loop is turned on or turned off again; if the mutual charging current is smaller than or equal to the safe current threshold value, no processing is carried out, and the first battery pack and the second battery pack still provide electric energy for the motor.
For example, when the first switch device and the second switch device are both closed, the controller detects the magnitude and direction of the mutual charging current between the first battery pack and the second battery pack, that is, the controller detects whether negative current flows to the first battery pack through the first switch device to charge the first battery pack, or the current detection unit detects whether negative current flows to the second battery pack through the second switch device to charge the second battery pack, when the mutual charging current flowing to the first battery pack through the first switch device, that is, the negative current flowing to the first battery pack is detected, the magnitude of the mutual charging current is obtained, and whether the mutual charging current is greater than a safety current threshold value is judged, if the mutual charging current is greater than the safety current threshold value, it is judged that the voltage of the first battery pack is lower relative to the voltage of the second battery pack, the controller controls the first switch device to be turned off, the first battery pack stops supplying power to the motor, the motor is supplied with electrical energy only by the second battery pack, which has a relatively high voltage. Similarly, when the controller detects the mutual charging current flowing to the second battery pack through the second switch device, the controller controls the second switch device to be switched off, the second battery pack stops supplying power to the motor, and only the first battery pack with relatively high voltage supplies power to the motor.
In the process of parallel discharge of the first battery pack and the second battery pack, the control unit continuously monitors the voltage, the temperature and other parameters of the two battery packs, reads the voltage, the current and the rotating speed of the motor fed back by the feedback module, if the voltage, the temperature and other parameters of any one battery pack exceed the set threshold, the power supply condition is not met, if the power supply is carried out by a single battery pack at the moment, the tool enters a protection mode, the power switch is shut down firstly and then the corresponding power switch device is disconnected, the damage to components of the tool is avoided, the safety of the tool is effectively ensured, if the power supply is carried out by double packs or multiple battery packs at the moment, the ultralimit battery pack is disconnected from a power supply loop, the ultralimit battery pack stops supplying power, the damage to the battery is avoided, the safety and the reliability of the battery pack are ensured, the service life of the battery is greatly prolonged.
For example, when the first switch device and the second switch device are both closed, if the voltage or the temperature of the first battery pack exceeds a set threshold value, and the first battery pack is determined not to meet the power supply condition, the first switch device is controlled to be switched off, and at the moment, the second battery pack is used for supplying power independently. However, under the condition that the second battery pack supplies power independently, the voltage or the temperature of the second battery pack also exceeds a set threshold, which indicates that the tool has a fault, at the moment, the tool enters a protection mode, and is shut down first, so that components such as a load and the like stop working, damage to the components due to sudden power failure is avoided, and then the second switch device is switched off, so that the safety and the reliability of the tool are ensured.
In addition, in one embodiment of the present invention, the electric power tool of the embodiment of the present invention further includes: a first battery receiving portion and a second battery receiving portion (not specifically identified in the drawings). The first battery accommodating part and the second battery accommodating part are used for accommodating and connecting the first battery pack and the second battery pack in a one-to-one correspondence mode.
In the above embodiments of the present invention, the first switching device and the second switching device comprise transistors, for example, MOSFETs or power MOSFETs.
It can be understood that the battery accommodating part is specifically used for fixedly arranging the battery pack and can be detachably arranged, so that the maintenance operation of a maintenance worker in the later period is facilitated, the repairability of a tool can be improved, and the battery accommodating part is simple and easy to realize.
Alternatively, in one embodiment of the invention, the power tool may be a lawn mower comprising a body on which a first battery pack and a second battery pack are arranged side by side. It should be noted that the electric tool may be a grass trimmer, a blower, a chain saw, a snow sweeper, or the like, and is not limited herein.
According to the electric tool provided by the embodiment of the invention, when the mutual charging current is greater than the safety current, the battery pack at the low-voltage side is disconnected, the battery damage caused by the fact that the mutual charging current exceeds the safety current is avoided, the safety risk is reduced and even effectively avoided, the abnormal battery is stopped to continue supplying power once the battery is abnormal, and the battery meeting the condition of continuing supplying power can be reconnected into the power supply loop, so that the battery pack is ensured to be connected in parallel, the endurance, the power and the service life of the battery are improved, the safety and the reliability of the battery pack are ensured, the safety risk of large-current mutual charging of the battery pack is effectively reduced, the service life of the battery is greatly prolonged, the service life of the electric tool is effectively ensured, and the applicability and the use experience of the tool.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (9)
1. An electric power tool, characterized by comprising:
a motor;
a first battery pack and a second battery pack connected in parallel for supplying electric energy to the motor;
the first switch device is connected between the first battery pack and the motor in series to switch on or off the connection between the first battery pack and the motor, and the second switch device is connected between the second battery pack and the motor in series to switch on or off the connection between the second battery pack and the motor; and
and the controller is used for monitoring the mutual charging current between the first battery pack and the second battery pack and controlling the corresponding switching device to cut off the connection between the battery pack with relatively low voltage and the motor when the mutual charging current is greater than a safe current threshold value.
2. The power tool of claim 1, wherein the controller further comprises a current detection unit for detecting the magnitude and direction of the mutual charging current between the first battery pack and the second battery pack, and the battery pack with the relatively low voltage is a battery pack to which the mutual charging current flows.
3. The power tool of claim 1, wherein the controller further comprises a voltage detection module for detecting voltages of the first and second battery packs and controlling the corresponding switching device to disconnect the battery pack having the relatively lower voltage from the motor when the mutual charging current is greater than a safety current threshold.
4. The power tool of claim 1, wherein the controller comprises:
the voltage detection unit is used for detecting a first current voltage of a battery pack in a power supply state in the first battery pack and the second battery pack;
the temperature detection module is used for detecting a first current temperature of a battery pack in a power supply state in the first battery pack and the second battery pack;
and the control unit is used for controlling the corresponding switch device to cut off the connection between the battery pack which does not meet the power supply condition and the motor when the first current temperature or the first current voltage does not meet the power supply condition.
5. The electric tool according to claim 4, wherein the temperature detecting unit and the voltage detecting unit are further configured to detect a second current temperature and a second current voltage of an idle battery pack of the first battery pack and the second battery pack, and when both the second current temperature and the second current voltage satisfy the power supply condition, the control unit controls the corresponding switch device to connect the battery pack satisfying the power supply condition to the motor, and the first battery pack and the second battery pack are connected in parallel to provide electric energy for the motor.
6. The power tool of claim 4, wherein the controller is further configured to receive a power-on command of the power tool, and close the first and second switching devices when the current temperature and the current voltage of the first and second battery packs satisfy the power supply condition.
7. The power tool of claim 1, wherein the first and second switching devices each comprise: the power supply device comprises a power-on loop and a power switch device, wherein the power-on loop and the power switch device are both arranged between a battery pack and the motor and are connected in parallel.
8. The power tool of claim 1, further comprising:
the battery pack comprises a first battery accommodating part and a second battery accommodating part, wherein the first battery accommodating part and the second battery accommodating part are used for accommodating and connecting the first battery pack and the second battery pack in a one-to-one correspondence manner.
9. The power tool of claim 1, wherein the power tool is a lawn mower comprising a body, the first and second battery packs being disposed side-by-side on the body.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911030910.3A CN112803506A (en) | 2019-10-28 | 2019-10-28 | Electric tool |
| PCT/CN2020/120122 WO2021082884A1 (en) | 2019-10-28 | 2020-10-10 | Electric tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911030910.3A CN112803506A (en) | 2019-10-28 | 2019-10-28 | Electric tool |
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| CN112803506A true CN112803506A (en) | 2021-05-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201911030910.3A Pending CN112803506A (en) | 2019-10-28 | 2019-10-28 | Electric tool |
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| Country | Link |
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| CN (1) | CN112803506A (en) |
| WO (1) | WO2021082884A1 (en) |
Cited By (1)
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| WO2024032318A1 (en) * | 2022-08-11 | 2024-02-15 | 南京泉峰科技有限公司 | Electronic combination, battery pack, and electric tool and charging control method therefor |
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| WO2021082884A1 (en) | 2021-05-06 |
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