CN112803506B - Electric tool - Google Patents
Electric tool Download PDFInfo
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- CN112803506B CN112803506B CN201911030910.3A CN201911030910A CN112803506B CN 112803506 B CN112803506 B CN 112803506B CN 201911030910 A CN201911030910 A CN 201911030910A CN 112803506 B CN112803506 B CN 112803506B
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- battery pack
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- battery
- power
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- 238000012544 monitoring process Methods 0.000 claims abstract description 3
- 238000001514 detection method Methods 0.000 claims description 21
- 230000002159 abnormal effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000002035 prolonged effect Effects 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 2
- 244000025254 Cannabis sativa Species 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Classifications
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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 power to the motor; the first switch device and the second switch device are connected in series between the first battery pack and the second battery pack and the motor in a one-to-one correspondence manner so as to conduct or cut off the connection between the first battery pack and 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 larger than the safety current threshold value. The electric tool can disconnect the battery pack at the low voltage side when the mutual charging current is larger 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 guaranteed, and the service life of the electric tool is effectively guaranteed.
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, a plurality of battery packs are connected in parallel in one power supply mode, although the battery endurance, the power and the service life of the battery are greatly improved due to the fact that the battery packs are connected in parallel, the voltage among each battery pack cannot be completely the same, so that potential differences can be formed among the battery packs, and accordingly, current can be formed, and the current flows from the battery pack with high potential to the battery pack with low potential to charge the battery pack with low potential, so that a mutual charging current is formed.
In the related art, if the temperature of the battery pack is detected to be between 0 ℃ and 45 ℃, the battery packs are left to charge each other. Once the mutual charging current is not controlled, and especially when the voltage difference of a plurality of battery packs of the tool is larger than a certain value, the mutual charging current may exceed the safety current of the battery, and certain safety risks exist for the battery, so that the battery is easily damaged, the service life of the battery is reduced, and the problem is to be solved.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent.
Therefore, an object of the present invention is to provide an electric tool capable of disconnecting a battery pack at a low voltage side when a mutual charging current is greater than a safety current, and avoiding battery damage caused by the mutual charging current exceeding the safety current.
To achieve the above object, an embodiment of the present invention provides an electric tool, including: a motor; a first battery pack and a second battery pack for providing electrical energy to the motor; a first switching device and a second switching device, the first switching device being connected in series between the first battery pack and the motor to turn on or off the connection between the first battery pack and the motor, the second switching device being connected in series between the second battery pack and the motor to turn 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 larger 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 larger 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 multi-pack parallel connection is ensured, 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 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 power 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, and the battery pack with relatively low voltage is a battery pack in 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 switching device to disconnect the battery pack having a relatively low voltage from the motor when the mutual charging current is greater than a safe 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 switching device to cut off the connection between the battery pack and the motor, wherein the connection does not meet the power supply condition, 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 the second current temperature and the second current voltage both meet the power supply condition, the control unit controls the corresponding switching device to conduct connection between the battery pack meeting the power supply condition and 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 electric tool, and close the first switching device and the second switching device when the current temperatures and the current voltages of the first battery pack and the second battery pack 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-on loop and the power switch device are arranged between the battery pack and the motor, and are connected in parallel.
In addition, in one embodiment of the present invention, the method further includes: 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 present invention, the power tool may be a mower including a body on which the first battery pack and the second battery pack 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 invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a schematic 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 illustrating a control method of the electric tool according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
A power tool according to an embodiment of the present invention is described below with reference to the accompanying drawings.
Fig. 1 is a schematic 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 invention includes: the motor 100, n battery packs (as shown by battery pack 201, battery packs 202, …, battery pack 20 n), a switching device (as shown by switching device 301, switching device 302, …, 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 switch devices are connected in series between the n battery packs and the motor 100 in a one-to-one correspondence manner so as to conduct or cut off the connection between the n battery packs and the motor 100, wherein n is a positive integer greater than 1.
In the present invention, a plurality of battery packs are connected in parallel, a closed loop is formed between the plurality of battery packs, when the voltages of the plurality of battery packs are different, a risk of cross charging exists in the loop formed between the plurality of battery packs, that is, a battery pack with a high voltage charges a battery pack with a low voltage, and the controller 400 is configured to monitor a cross charging current, that is, a cross charging current, between any two battery packs in the plurality of battery packs connected in parallel, and control a corresponding switching device to cut off connection between a battery pack with a relatively low voltage in any two battery packs and the motor 100 when the cross charging current is greater than a safety current threshold. 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, please refer to fig. 2 for illustrating a dual-pack control circuit of the present invention, in the 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 electric energy to 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 conducting and disconnecting 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 conducting and disconnecting 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 the loop formed by the first battery pack 201, the first switching device 301, the second battery pack 202, and the second switching device 302, and when the mutual charging current is greater than the safe current threshold, the controller 400 controls the switching device corresponding to the battery pack with relatively lower voltage to be turned off, so that the battery pack with relatively higher voltage separately provides the electric energy to the motor 100. When the mutual charging current is larger than the safety current threshold value, the battery pack at the low voltage side is disconnected, 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.
In the embodiment of the invention, two battery packs are connected in parallel, which belongs to a short circuit and is easy to generate the condition of cross charging. If the internal resistances of both battery packs are close to zero, the crossover current will be infinite, resulting in burning out the batteries. The actual internal resistance of the battery pack is of course not zero, but the cross-charging current will also be significant. The direction of the current is from the higher voltage power supply (direction of discharge), and the current flows backward into the lower voltage power supply (direction of charge). Therefore, the voltage of the battery pack may be detected in various ways, for example, by the voltage detection module, or by the current detection unit 4011, and the schemes of the voltage detection module and the current detection unit 4011 are described in detail below.
In one embodiment of the present invention, the controller 400 includes a current detecting unit 4011 for detecting the magnitude and direction of the inter-charging current between the first battery pack 201 and the second battery pack 202, that is, the current detecting unit 4011 detects whether a negative current flows 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 a negative current flows 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 inter-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 inter-charging current is obtained, and determines whether the inter-charging current is greater than a safe current threshold, if the inter-charging current is greater than the safe current threshold, the controller 400 controls the first switching device 301 to turn off, which indicates that the voltage of the first battery pack 201 is lower than the voltage of the second battery pack 202, and the first battery pack 201 stops supplying the electric power to the electric motor 100 only from the second battery pack 202, which is relatively higher in voltage. Similarly, when the current detecting unit 4011 detects the inter-charging current flowing to the second battery pack 202 through the second switching device 302, that is, the negative current flowing to the second battery pack 202, the magnitude of the inter-charging current is obtained, and when the inter-charging current is greater than the safe current threshold, it is indicated that the voltage of the second battery pack 202 is lower than the voltage of the first battery pack 201, and the controller 400 controls the second switching 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 having a relatively high 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 used for detecting voltages of the first battery pack 201 and the second battery pack 202, the current detection unit 4011 is used for detecting a magnitude of a mutual charging current in a parallel loop formed by the first battery pack 201 and the second battery pack 202, when the mutual charging current is greater than a safe current threshold, if at this time, the voltage of the first battery pack 201 is greater than the voltage of the second battery pack 202, 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 embodiment is exemplified by the first battery pack 201 and the second battery pack 202, it should be understood by those skilled in the art that any electric tool in fig. 1 may 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.
The invention needs to be explained that although the multi-pack parallel connection can improve the endurance capacity, the power and the service life of the battery, once the mutual charging current is uncontrolled, the battery is easily damaged and the service life of the battery is reduced, therefore, the embodiment of the invention firstly detects the mutual charging current between two parallel battery packs in real time, judges whether the mutual charging current is larger than the safe current threshold value or not, and controls whether a single battery pack provides electric energy for the motor or two battery packs provide electric energy for the motor in parallel according to the judging result.
The safety current threshold may be set by a person skilled in the art according to the actual situation, and preferably, the safety threshold 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, the larger the upper limit of the mutual charging current, the faster the temperature of the battery pack rises, and the higher the requirement on the safety of the battery.
That is, in order to solve the problem of how to control the mutual charging current, avoid exceeding the safety current, disconnect the battery pack at the low voltage side, and stop the battery pack at the low voltage side from supplying power to the tool, so that when the tool is used by a plurality of packs in parallel, the safety risk of heavy 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, referring to fig. 1, a controller 400 includes: a detection unit 401 and a control unit 402. The detection unit 401 may include a temperature sensor and a voltage detection module in particular. Wherein the temperature sensor is used for detecting a first current temperature of a battery pack in a power supply state in the first battery pack 201 and the second battery pack 202, and the voltage detection module is used for detecting a first current voltage of the battery pack in the power supply state in the first battery pack 201 and the second battery pack 202. The control unit 402 is configured to control the corresponding switching device to disconnect the battery pack, which 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 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 fails, for example, if the temperature of the battery pack is greater than a preset value or the voltage is greater than a preset value, the battery is indicated to be abnormal and is not suitable for continuing to supply power, i.e. the power supply condition is not met, the power supply to the tool is stopped, so that not only the battery is prevented from being damaged, but also other batteries are prevented from being influenced, and even the tool is prevented from being damaged. It should be noted that the power supply conditions may be set by those skilled in the art according to actual situations, and are not particularly limited herein.
In addition, in one embodiment of the present invention, the temperature sensor is further configured to detect a second current temperature of the battery pack in an 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 of the battery pack satisfying the power supply condition with the motor 100.
That is, in the embodiment of the present invention, for the battery pack that was previously disconnected due to low voltage, i.e., the battery pack in the idle state, the embodiment of the present invention can detect parameters such as voltage, temperature, etc. of the battery pack. If the temperature and the voltage of the battery pack in the idle state are within the set range, the battery pack in the idle state has the condition of being connected into the power supply loop to continue to supply power, and the battery pack can be connected into the power supply loop to be connected with other battery packs in parallel to supply power to the tool; otherwise, after the battery pack in the idle state is disconnected from the power supply loop, the high-voltage battery pack supplies power until the tool is restarted.
In addition, if parameters such as voltage, temperature and the like of the battery pack disconnected due to the failure, that is, the battery pack in an abnormal state, also satisfy the 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 battery pack from the motor 100 directly 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, if the first battery pack 201 or the second battery pack 202 alone supplies power does not satisfy the power supply condition.
Specifically, when the number of battery packs supplied with power is smaller than a certain value, for example, only one battery pack is powered by a single battery pack, once the parameters such as voltage, temperature and the like of the battery pack supplied with power are not in a preset range, the last battery pack is not suitable for continuing to supply power, so that power supply is stopped, damage to a battery is avoided, even tool damage is caused, corresponding fault reminding can be performed, for example, an acoustic reminding device and/or an optical reminding device are controlled to perform fault reminding, and user experience is improved.
It can be understood that in the operation process, the embodiment of the invention continuously monitors the parameters such as the voltage, the temperature and the like of the battery packs, if the parameters such as the voltage, the temperature and the like of any one battery pack exceed the preset range, the tool enters the protection mode if the power is supplied by a single pack at the moment, the power supply is stopped, and if the power is supplied by a plurality of packs at the moment, 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 to stop power supply, or may include other corresponding control strategies, such as rescreening the battery pack in the idle state and connecting 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 in detail herein.
Further, in an embodiment of the present invention, the controller 400 is further configured to receive a power-on command, please refer to fig. 2, when the trigger switch 700 is turned on, 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 after the controller 400 receives the power-on command, and if so, the first switch device 301 and the second switch device 302 are turned on. 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 an open state and the second switching device 301 to be closed.
That is, when the tool is started, the battery packs meeting the power supply condition are connected into the power supply loop, when the battery packs are connected in parallel, if the mutual charging current is greater 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 power is restarted and shut down, and if the mutual charging current is less than the set threshold value, the low-voltage battery pack can be mutually 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 a current operating parameter of the load. When the current operation parameter does not satisfy the disconnection control condition, the controller 400 controls the driving module 600 to decrease the current operation parameter of the load or disconnect the battery pack from the motor 100.
It can be understood that the embodiment of the invention can read the parameters such as the voltage, the current, the rotating speed and the like of the fed-back motor, and once the current working parameters do not meet the disconnection control conditions, if the power supply of a single battery cannot meet the requirement of a load, which means that the battery pack at the low-voltage side cannot be disconnected, the load is reduced or the power supply is stopped, and then the battery pack at the low-voltage side is disconnected, so that the safety and the reliability of the battery are ensured, and the safety accident is avoided.
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, …, power-up loop 30n 1) and power switching devices (shown as power switching device 3012, power switching devices 3022, …, power switching device 30n 2). The power-on 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 to control the battery power. Although the following embodiments take the example of controlling the closing and opening of the power switching devices to implement multi-pack parallel connection, it should be understood by those skilled in the art that any of the batteries in fig. 1 may be configured in a similar manner, i.e., the connection and configuration of the battery packs and the control power switching devices are merely illustrative, and the present invention is not limited to this connection and configuration.
As shown in fig. 1, the switching device includes a power-on loop and a power switching device corresponding to each battery pack, and the embodiment of the invention can control the power switching device to be turned on or off to realize multi-pack parallel connection, so as to control the mutual charging current in a safer 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 switching means and the second switching means are closed. In one embodiment of the present invention, before the first switch device and the second switch device are closed, battery parameters such as temperatures and voltages of the first battery pack and the second battery pack are obtained, if the temperatures and voltages of the first battery pack and the second battery pack are within 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 no longer in the preset range, the first switch device is in an open state, the second switch device is closed, 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 in the preset range after a period of time, the first switch device is controlled to be closed.
Step S20: and detecting a 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 battery pack with high voltage charges the battery pack with low voltage, namely, a mutual charging current exists between the first battery pack and the second battery pack, the controller detects whether a cross charging current exists, if so, the controller acquires the magnitude of the cross charging current, and meanwhile, the magnitude relation between the cross charging current, namely, the mutual charging current and a safety current threshold value is judged.
Step S30: if the mutual charging current is larger than the safety current threshold value, the corresponding switching device of the battery pack with relatively low control voltage is disconnected. In the invention, if the controller detects that the mutual charging current is larger than the safety 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 safety current threshold value in the two battery packs connected in parallel, disconnecting the battery pack with lower voltage from the power supply loop, and supplying power by the battery pack with higher voltage until the battery pack is restarted; if the mutual charging current is less than or equal to the safe current threshold value, the first battery pack and the second battery pack still provide electric energy for the motor without processing.
For example, when both the first switching device and the second switching device are 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 switching device to charge the first battery pack, or the current detecting unit detects whether negative current flows to the second battery pack through the second switching device to charge the second battery pack, when the mutual charging current flowing to the first battery pack through the first switching 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 safe current threshold value is judged, if the mutual charging current is greater than the safe current threshold value, the controller controls the first switching device to be turned off, the first battery pack stops supplying power to the motor, and only the second battery pack with relatively high voltage supplies power to the motor. Similarly, when the controller detects a charging current flowing to the second battery pack through the second switching device, the controller controls the second switching device to be turned 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 parallel discharging process 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 single battery pack supplies power at the moment, the tool enters a protection mode, the corresponding power switch device is turned off first and then turned off, the damage to the components of the tool is avoided, the safety of the tool is effectively ensured, and if the double battery pack or the plurality of battery packs supply power at the moment, the overrun battery packs are turned off from the power supply loop, the overrun battery packs supply power is stopped, the damage to the battery is avoided, the safety and the reliability of the battery packs are ensured, the service life of the battery is greatly prolonged, and the reliability of the tool is further ensured.
For example, when the first switching device and the second switching device are both closed, if the voltage or the temperature of the first battery pack exceeds the set threshold, and it is determined that the first battery pack does not meet the power supply condition, the first switching device is controlled to be opened, and at this time, the second battery pack is independently supplied with power. However, under the condition that the second battery pack is independently powered, the voltage or the temperature of the second battery pack exceeds a set threshold value, which indicates that the tool fails, and the tool enters a protection mode, is powered off firstly, so that components such as a load are stopped, damage to the components caused by sudden power failure is avoided, and then the second switching device is disconnected, 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 housing portion and a second battery housing portion (not specifically identified in the figures). 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.
In the above embodiments of the invention, the first switching means and the second switching means comprise transistors, for example MOSFETs or power MOSFETs.
It can be understood that the battery accommodation portion is particularly used for fixedly arranging a battery pack, and can be detachably arranged, so that later maintenance operation of maintenance personnel can be facilitated, repairability of tools can be improved, and the device is simple and easy to realize.
Alternatively, in one embodiment of the present invention, the power tool may be a mower, the mower including a body, and the first battery pack and the second battery pack are disposed side by side on the body. The electric tool may be a grass cutter, a blower, a chain saw, a snowplow, or the like, and is not particularly limited herein.
According to the electric tool provided by the embodiment of the invention, when the mutual charging current is larger than the safety current, the battery pack at the low-voltage side is disconnected, so that 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, once the abnormal condition of the battery occurs, the abnormal battery is stopped to continue to supply power, the battery meeting the condition of continuing to supply power can be connected into the power supply loop again, the multi-pack parallel connection is ensured, 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 the 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 service experience of the electric tool are improved.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means 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 present invention. In this specification, schematic representations of the above terms are not necessarily directed 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, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (9)
1. A power tool, comprising:
A motor;
a first battery pack and a second battery pack connected in parallel for supplying electric power to the motor;
A first switching device and a second switching device, the first switching device being connected in series between the first battery pack and the motor to turn on or off the connection between the first battery pack and the motor, the second switching device being connected in series between the second battery pack and the motor to turn 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 larger than a safe current threshold value;
The device comprises a feedback module and a driving module, wherein the feedback module is used for feeding back the current working parameter of a load, the driving module is used for adjusting the current working parameter of the load, and when the current working parameter does not meet the disconnection control condition, the controller controls the driving module to reduce the current working parameter of the load or disconnect the connection between a battery pack and a motor.
2. The power tool according to claim 1, wherein the controller further comprises a current detection unit for detecting a magnitude and a direction of a mutual charge flow between the first battery pack and the second battery pack, and the battery pack having a relatively low voltage is a battery pack to which the mutual charge flow is directed.
3. The power tool of claim 1, wherein the controller further comprises a voltage detection module for detecting voltages of the first battery pack and the second battery pack and controlling the corresponding switching device to disconnect the battery pack having a relatively lower voltage from the motor when the mutual charge current is greater than a safe 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 switching device to cut off the connection between the battery pack and the motor, wherein the connection does not meet the power supply condition, when the first current temperature or the first current voltage does not meet the power supply condition.
5. The power 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 a battery pack in an idle state among the first battery pack and the second battery pack, and when the second current temperature and the second current voltage both satisfy the power supply condition, the control unit controls the corresponding switching device to turn on connection of the battery pack satisfying the power supply condition with the motor, the first battery pack and the second battery pack being connected in parallel to supply electric power to the motor.
6. The power tool of claim 4, wherein the controller is further configured to receive a power-on command for the power tool and to close the first and second switching devices when the current temperatures and the current voltages of the first and second battery packs satisfy the power supply condition.
7. The power tool according to claim 1, wherein the first and second switching devices each include: the power-on loop and the power switch device are arranged between the battery pack and the motor, and are connected in parallel.
8. The power tool of claim 1, further comprising:
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 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 |
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| CN201911030910.3A CN112803506B (en) | 2019-10-28 | 2019-10-28 | Electric tool |
| PCT/CN2020/120122 WO2021082884A1 (en) | 2019-10-28 | 2020-10-10 | Electric tool |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911030910.3A CN112803506B (en) | 2019-10-28 | 2019-10-28 | Electric tool |
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| CN112803506B true CN112803506B (en) | 2024-06-14 |
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| CN117595418A (en) * | 2022-08-11 | 2024-02-23 | 南京泉峰科技有限公司 | Electronic combination, electric tool and control method thereof |
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| WO2013127099A1 (en) * | 2012-02-28 | 2013-09-06 | 智晖有限公司 | Method for charge balancing and load control in parallel battery packs |
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| WO2021082884A1 (en) | 2021-05-06 |
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