CN111584789B - Power tool and system thereof - Google Patents

Abstract

The application provides an electric tool system, which comprises an electric tool and a battery pack, wherein the battery pack comprises two battery packs, and the electric tool is correspondingly provided with two negative terminals and two positive terminals. The electric tool is also provided with a linkage switch which comprises two contact pieces, a pressing plate assembly and a linkage assembly which is movably arranged. The two contact pieces are respectively connected with one positive electrode terminal and one negative electrode terminal of the corresponding different battery packs. The pressing plate assembly is provided with four conductive sheets connected with the four electrode terminals respectively. One side of the linkage component is provided with a guide tab, and the other side is provided with a plurality of rotary tabs. When the conducting sheet is contacted with the two contact sheets, one positive electrode terminal and one negative electrode terminal of the corresponding different battery packs are electrically connected; when the switching sheet is contacted with the conducting strip, the two positive terminals are electrically connected, and the two negative terminals are electrically connected. The linkage switch can switch the connection state of the four electrode terminals, thereby controlling the output voltage of the matched battery pack.

Description

Power tools and their systems

Technical Field

The invention relates to an electric tool, in particular to an electric tool with a linkage switch.

Background Art

At present, there are more and more handheld power tools on the market, especially in the garden tool industry, such as pruners, mowers, tillers, and lawn mowers. In order to extend the use time and increase the power of power tools, while taking into account the simplicity and versatility of battery pack replacement, power tools usually adopt a multi-battery pack solution, and the most common one is a dual battery pack. When using, both battery packs need to be installed in the corresponding slots of the power tool to provide an output voltage that matches the rated working voltage of the power tool, so that the power tool can work normally; if only one battery pack is installed, the power tool cannot work normally.

Therefore, in view of the above problems, it is necessary to improve the existing electric tools.

Summary of the invention

The invention provides an electric tool having a linkage switch capable of switching the output voltage of a battery pack.

Specifically, the present invention is implemented through the following technical solutions: an electric tool, provided with four electrode terminals for cooperating with two battery packs of a battery pack, including two positive terminals and two negative terminals, characterized in that: the electric tool is provided with a linkage switch, the linkage switch includes two contact pieces, a pressure plate assembly and a movably arranged linkage assembly, the two contact pieces are electrically connected to a positive terminal and a negative terminal of corresponding different battery packs, respectively, the pressure plate assembly is provided with four conductive pieces electrically connected to the four electrode terminals, respectively; the linkage assembly is provided with a first side surface and a second side surface opposite to each other, wherein the first side surface is provided with a conductive piece, and the second side surface is provided with a plurality of adapter pieces; when the conductive piece contacts the two contact pieces, the one positive terminal and the one negative terminal are electrically connected, and at this time, the plurality of adapter pieces are separated from the four conductive pieces; when the plurality of adapter pieces are in contact with the four conductive pieces, the two positive terminals are electrically connected, and the two negative terminals are electrically connected, and at this time, the conductive piece is separated from the two contact pieces. The electric tool of the present application can change the connection mode of the four electrode terminals respectively connected to the electrodes of the battery pack through the linkage switch, thereby controlling the series-parallel state of the two battery groups in the battery pack.

According to one embodiment of the present invention, in the initial state, the conductive sheet contacts the two contact sheets, and the linkage assembly moves toward the pressure plate assembly after being pressurized, so that the conductive sheet is separated from the two contact sheets, and the plurality of adapter sheets include four, which are respectively in contact with the four conductive sheets, and are electrically connected between the two adapter sheets corresponding to the two positive terminals through the conductive sheets, and are electrically connected between the two adapter sheets corresponding to the two negative terminals through the conductive sheets.

According to an embodiment of the present invention, the linkage assembly further includes an elastic member disposed between the linkage assembly and the pressure plate assembly, and the elastic member drives the linkage assembly to reset.

According to an embodiment of the present invention, the pressure plate assembly and the linkage assembly are respectively provided with a receiving cavity for accommodating the elastic member.

According to one embodiment of the present invention, the electric tool is also provided with a mounting base, the linkage switch is installed on the mounting base, the mounting base is provided with a mounting groove, the contact piece is fixed on the side wall of the mounting base, the pressure plate assembly is fixed to the top of the mounting groove by screws, and the linkage assembly is movably arranged in the mounting groove and is located between the contact piece and the pressure plate assembly.

According to an embodiment of the present invention, the linkage switch further comprises a micro button, wherein the micro button is provided with a head and a rod, and the head is pressed to drive the rod to drive the linkage assembly.

The present invention can also be implemented by the following technical solution: an electric tool system, characterized in that: the electric tool system comprises a first battery pack, a second battery pack and the electric tool as described in any one of claims 1 to 5, the electric tool comprises two slots, including a first slot for accommodating the first battery pack and a second slot for accommodating the second battery pack, each slot is provided with four electrode terminals, and the two contact pieces and four conductive pieces of the linkage switch are respectively connected to the corresponding electrode terminals in the second slot. The electric tool system of the present application can change the connection mode of the four electrode terminals respectively connected to the electrodes of the battery pack through the linkage switch, thereby realizing the control of the series-parallel state of the two battery packs in the battery pack.

According to one embodiment of the present invention, the linkage switch also includes a micro button, which is provided with a head and a rod, wherein the head protrudes into the first slot, and when the first battery pack is inserted into the first slot, the linkage assembly is driven to move toward the pressure plate assembly.

According to one embodiment of the present invention, the four electrode terminals include a first positive terminal and a first negative terminal electrically connected to the same battery pack, and a second positive terminal and a second negative terminal electrically connected to another battery pack, wherein the two contact pieces are electrically connected to the first positive terminal and the second negative terminal, respectively; the linkage component is also provided with two other contact pieces, and the other two contact pieces are respectively connected to the first positive terminal and the second negative terminal in the first slot, and the linkage component is also provided with another conductive piece connecting the other two contact pieces.

According to one embodiment of the present invention, the electric tool is also provided with another linkage switch having the same structure as the linkage switch, the two contact pieces and the four conductive pieces of the other linkage switch are respectively connected to the corresponding electrode terminals in the first slot, the other two contact pieces of the other linkage switch are respectively connected to the first negative terminal and the second positive terminal in the second slot, and the other linkage switch is driven when the second battery pack is inserted into the second slot; the second positive terminal in the first slot remains connected to the first negative terminal in the second slot.

It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a three-dimensional assembly diagram of the electric tool system of the present invention.

2(a) to 2(c) are diagrams showing three working states of two battery packs of the electric tool system of the present invention.

3( a ) and 3 ( b ) are partial perspective views of an electric tool according to a first embodiment of the present invention.

FIG. 4 is a connection diagram of the switch of the electric tool in the first embodiment in an initial state.

5(a) to 5(c) are connection diagrams of the switch in the first embodiment corresponding to three working states.

FIG. 6 is a connection diagram of a switch of an electric tool in an initial state according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram showing the connection between the switch and the micro control unit in the second embodiment.

8(a) to 8(c) are connection diagrams of the switch in the second embodiment corresponding to three working states.

FIG. 9 is a connection diagram of a switch in an initial state in a third embodiment of the electric tool of the present invention.

FIG. 10 is a partial perspective view of the electric tool according to the third embodiment.

11( a ) to 11 ( c ) are schematic diagrams showing the connections of the switch in the third embodiment corresponding to three working states.

FIG. 12 is a partial perspective view of an electric tool according to a fourth embodiment of the present invention.

FIG. 13 is a partial exploded perspective view of the electric tool according to the fourth embodiment.

FIG. 14 is a perspective exploded view of a linkage switch of an electric tool according to a fourth embodiment.

FIG. 15 is a wiring diagram of the contact piece of the linkage switch.

FIG. 16 is an assembly diagram of the linkage component of the linkage switch.

FIG. 17 is an assembly diagram of the pressure plate assembly of the linkage switch.

FIG. 18 is a plan view of a linkage assembly of a linkage switch.

FIG. 19 is another plan view of the linkage assembly of the linkage switch.

Figure 20 is a wiring diagram of the pressure plate assembly of the linkage switch.

FIG. 21 is a plan view of the pressure plate assembly of the linkage switch.

Figure 22 is a wiring diagram of the linkage switch.

FIG. 23 is similar to FIG. 22 , showing the change in position of the linkage switch when the first battery pack is inserted.

FIG. 24 is similar to FIG. 22 , and shows the position change of the linkage switch when the first battery pack and the second battery pack are inserted simultaneously.

FIG. 25 is a partial plan view of a battery pack for an electric tool according to a fifth embodiment of the present invention.

FIG. 26 is a partial plan view of the battery pack in FIG. 22 in another state.

FIG. 27 is a plan view of the serial male socket in FIG. 22 .

Description of Figure Numbers:

Power tool 100, first battery pack 10, second battery pack 20, first slot 11, second slot 21, first negative terminal 101, second negative terminal 103, first positive terminal 102, second positive terminal 104, first negative terminal 105, second negative terminal 107, first positive terminal 106, second positive terminal 108, switch terminal 12, switch terminal 22, switch terminal 13, first male plug 14, second male plug 24, mounting slot 15, mounting slot 1 51, screw column 16, linkage switch 3, contact piece 31, first contact 311, linkage assembly 32, insulating substrate 321, conductive piece 322, second contact 323, adapter piece 324, fourth contact 325, elastic member 33, pressure plate assembly 34, insulating plate 341, conductive piece 342, third contact 343, micro button 35, screw 36, parallel plug seat 50, electrode plug 41, parallel terminal 51, series male socket 60, insulating column 61, series terminal 62.

DETAILED DESCRIPTION

Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices, systems, equipment, and methods consistent with some aspects of the present invention as detailed in the appended claims. In order to avoid obscuring the present invention with unnecessary details, only structures and/or processing steps closely related to the scheme of the present invention are shown in the drawings, and other details that are not closely related to the present invention are omitted.

The present invention provides a portable electric tool 100 that can be powered by an electric energy storage device for wireless operation. The electric tool 100 can be a pruner, a chain saw, a hair dryer, a cleaning machine, a lawn mower, a tiller, etc. In this embodiment, an electric drill is used as an example for description.

In this embodiment, the rated voltage of the power tool 100 is 48V, and two battery packs can be connected. Each battery pack includes at least two battery packs with the same rated voltage, and each battery pack may include one or more battery cells. In this embodiment, the output voltage of each battery pack is 24V. Referring to FIG1 , two slots are respectively provided on the left and right sides of the bottom of the power tool 100, and each slot is used to accommodate and cooperate with one of the battery packs. The structures of the two battery packs are exactly the same, and the structures of the two slots are also exactly the same. For the convenience of description, the present invention defines the two battery packs as a first battery pack 10 and a second battery pack 20, respectively. Each battery pack includes two battery packs, and the two slots are respectively defined as a first slot 11 that cooperates with the first battery pack 10 and a second slot 21 that cooperates with the second battery pack 20.

As shown in FIG. 2(a) to FIG. 2(c), the electric tool 100 of the present invention has three working states. The first state is that only the first battery pack 10 is configured in the first slot 11; the second state is that only the second battery pack 20 is configured in the second slot 12; and the third state is that the first battery pack 10 and the second battery pack 20 are respectively configured in the first slot 11 and the second slot 12. The first and second working states can be regarded as the same working state, that is, only one of the slots is configured with a battery pack, which can be defined as a single-pack working state, and the third working state can be defined as a dual-pack working state. Both working states can achieve a fixed voltage output of 48V, that is, whether one battery pack 10, 20 or two battery packs 10, 20 are configured, the electric tool 100 can obtain a rated working voltage of 48V and can work normally. Each battery pack of each battery pack 10, 20 is provided with a pair of positive and negative electrodes, specifically including a first negative electrode, a second negative electrode, a first positive electrode and a second positive electrode. As shown in FIG. 3(a) and FIG. 3(b), a group of electrode terminals is provided in each slot, and the electrode terminals in the first slot include a first negative terminal 101, a second negative terminal 103, a first positive terminal 102, and a second positive terminal 104, which are respectively connected to the first negative electrode, the second negative electrode, the first positive electrode, and the second positive electrode of the first battery pack 10. The electrode terminals in the second slot are respectively a first negative terminal 105, a second negative terminal 107, a first positive terminal 106, and a second positive terminal 108, which are respectively connected to the first negative electrode, the second negative electrode, the first positive electrode, and the second positive electrode of the second battery pack 20. By setting different connection modes of the eight electrode terminals 101, 102, 103, 104, 105, 106, 107, and 108, the connection mode between the two battery packs inside the battery packs 10 and 20 inserted into the slots 11 and 12 can be adjusted.

FIG. 2( a ) to FIG. 2( c ) are schematic diagrams of the connection of electrode terminals. The “1-” and “1+” on the left side of the figure represent the first negative terminal 101 and the first positive terminal 102 corresponding to the first negative electrode and the first positive electrode of the first battery pack 10, and the “2-” and “2+” represent the second negative terminal 103 and the second positive terminal 104 corresponding to the second negative electrode and the second positive electrode of the first battery pack 10. The “1-” and “1+” on the right side of the figure represent the first negative terminal 105 and the first positive terminal 106 corresponding to the first negative electrode and the first positive electrode of the second battery pack 20, and the “2-” and “2+” represent the second negative terminal 107 and the second positive terminal 108 corresponding to the second negative electrode and the second positive electrode of the second battery pack 20. The first negative terminal 101 represented by the “1-” on the left side is the negative output terminal, and the second positive terminal 108 represented by the “2+” on the right side is the positive output terminal. The following related figures follow this definition, and if there is any difference, it will be explained separately.

FIG2(a) corresponds to the first working state, in which the electric tool 100 is only equipped with the first battery pack 10. The "2-" on the left side of the figure representing the second negative terminal 103 and the "1+" on the right side of the figure representing the first positive terminal 102 are connected, so that the second negative electrode in the first battery pack 10 and the first positive electrode are connected, so that the two battery groups of the first battery pack 10 are connected in series, and the output voltage of the first battery pack 10 is 48V; the "1-" on the right side of the figure representing the first negative terminal 105, the "1+" on the right side of the figure representing the first positive terminal 106, the "2-" on the right side of the figure representing the second negative terminal 107 and the "2+" on the right side representing the second positive terminal 108 (total positive) are connected, that is, all four electrodes for electrical connection with the second battery pack 20 are electrically connected. Moreover, the "2+" on the left side representing the second positive terminal 104 is connected to the "2+" on the right side representing the second positive terminal 108 (total positive), so that the first battery pack 10 directly outputs to the outside, and the output voltage is 48V.

FIG2(b) corresponds to the second working state, in which the electric tool 100 is only equipped with the second battery pack 20. The right side of the figure represents the connection of "2-" of the second negative terminal 107 and the connection of "1+" of the first positive terminal 106, so that the first positive electrode and the second negative electrode in the second battery pack 20 are connected to form two battery groups of the second battery pack 20 connected in series, and the output voltage of the second battery pack 20 is 48V; the left side of the figure represents the connection of "1-" of the first negative terminal 101, the connection of "1+" of the first positive terminal 102, the connection of "2-" of the second negative terminal 103 and the connection of "2+" of the second positive terminal 104, that is, the four electrodes for electrical connection with the first battery pack 10 are all electrically connected, and the "1-" of the first negative terminal 105 on the right side is connected to the "1-" (total negative) of the first negative terminal 101 on the left side, and the second battery pack 20 directly outputs to the outside, and the output voltage is 48V.

Figure 2(c) corresponds to the third working state. The electric tool 100 is configured with the first battery pack 10 and the second battery pack 20 at the same time. The "1-" representing the first negative terminal 101 on the left is connected to the "2-" representing the second negative terminal 103, and the "1+" representing the first positive terminal 102 is connected to the "2+" representing the second positive terminal 104, so that the first negative electrode and the second negative electrode of the first battery pack 10 are connected, and the first positive electrode is connected to the second positive electrode, so that the two battery groups of the first battery pack 10 are in parallel state, and the output voltage of the first battery pack 10 is 24V. The "1-" on the right side representing the first negative terminal 105 is connected to the "2-" representing the second negative terminal 107, and the "1+" representing the first positive terminal 106 is connected to the "2+" representing the second positive terminal 108, so that the first negative electrode and the second negative electrode of the second battery pack 20 are connected, and the first positive electrode is connected to the second positive electrode, so that the two battery groups of the second battery pack 20 are in a parallel state, and the output voltage of the second battery pack 20 is 24V. In addition, the "1+" on the left side representing the first positive terminal 102 and the "2+" representing the second positive terminal 104 are connected to the "1-" on the right side representing the first negative terminal 105 and the "2-" representing the second negative terminal 107, that is, the positive electrode of the first battery pack 10 is connected to the negative electrode of the second battery pack 20, so that the first battery pack 10 and the second battery pack 20 are in a series state, forming a working state in which the two battery groups inside the single battery pack 10, 20 are connected in parallel and the two battery packs 10, 20 are connected in series, and the output voltage is 48V.

It can be seen that in the above three working states, the first battery pack 10 and the second battery pack 20 can provide a voltage of 48V when used alone, and can also provide a voltage of 48V when used together, ensuring that the power tool 100 works normally at the rated working voltage of 48V. Specifically, when the power tool 100 is working with a dual battery pack, the two battery packs in each battery pack are connected in parallel to provide a low-voltage output, and the two battery packs are connected in series; when the power tool 100 is working with a single battery pack, the two battery packs in the single battery pack are connected in series to provide a high-voltage output. The power tool system can adjust the connection method of the two battery packs in the battery pack according to the situation of the power tool 100 using the battery pack.

In this embodiment, the first battery pack 10 and the second battery pack 20 are dual-pressure packs, which output 48V when used alone, and output 24V respectively and are connected in series with each other when used together; as a variation, the first battery pack 10 and the second battery pack 20 can also use single-pressure packs, which output 48V when used alone, and output 48V respectively and are connected in parallel with each other when used together.

The present invention also provides a plurality of switches, which are arranged between the electrode terminals. By controlling the on and off of the switches, the connection mode of the two battery packs in the battery pack can be adjusted and controlled to achieve the switching and control mode of the above three working states. The present invention provides multiple embodiments of switch settings, which will be described below.

Embodiment 1

As shown on the left side of reference Figure 4, the electric tool 100 is provided with a first group of control switches for controlling the first battery pack 10, including a first switch BS1 set between "1-" representing the first negative terminal 101 and "2-" representing the second negative terminal 103, a second switch BS2 set between "1+" representing the first positive terminal 102 and "2+" representing the second positive terminal 104, and two third switches AS3 and BS3 set between "2-" representing the second negative terminal 103 and "1+" representing the first positive terminal 102.

As shown on the left side of reference Figure 4, the power tool 100 is provided with a second group of control switches for controlling the second battery pack 20, including a fourth switch AS1 set between "1-" representing the first negative terminal 105 and "2-" representing the second negative terminal 107, a fifth switch AS2 set between "1+" representing the first positive terminal 106 and "2+" representing the second positive terminal 108, and two sixth switches AS4 and BS4 set between "2-" representing the second negative terminal 103 and "1+" representing the first positive terminal 102.

The first group of control switches is used to adjust the electrode connection mode of the first battery pack 10, and the second group of control switches is used to adjust the electrode connection mode of the second battery pack 20. FIG. 4 shows the initial state of each switch, wherein the first switch BS1 and the second switch BS2 are normally open switches, that is, they are initially in the disconnected state, and the third switches AS3 and BS3 are normally closed switches, that is, they are initially in the on state. The fourth switch AS1 and the fifth switch AS2 are normally open switches, and the sixth switch AS4 and BS4 are normally closed switches. The "2+" representing the second positive terminal 104 of the first battery pack 10 is directly connected to the "1-" representing the first positive terminal 105 of the second battery pack 20. That is, when each switch does not switch state, the first battery pack 10 and the second battery pack 20 can be connected in series, and the two battery packs in each battery pack 10, 20 can be connected in series.

It should be noted that a normally closed switch refers to a switch in which, in an initial state, its two contact parts are in a contact state so that the electrodes electrically connected to the two contact parts are in a connected state, and the electrical connection state of the two contact parts can be changed by an external object, so that the two contact parts are switched from a contact state to a disconnected state, for example, a normally closed switch. A normally open switch refers to a switch in which, in an initial state, its two contact parts are in a disconnected state so that the electrodes electrically connected to the two contact parts are in a disconnected state, and the electrical connection state of the two contact parts can be changed by an external object, so that the two contact parts are switched from a disconnected state to a connected state, for example, a normally open switch. Of course, a normally open switch is not limited to a normally open terminal, and a normally closed switch is not limited to a normally closed terminal. All implementations that can achieve the same function are within the scope of protection of this invention.

3(a) and 3(b), the four switch terminals 12 corresponding to the fourth switch AS1, the fifth switch AS2, the third switch AS3 and the sixth switch AS4 are arranged in the first slot 11 and triggered by the first battery pack 10. The four switch terminals 22 corresponding to the first switch BS1, the second switch BS2, the third switch BS3 and the sixth switch BS4 are arranged in the second slot 12 and triggered by the second battery pack 20.

Referring to Figures 5(a) to 5(c), and in combination with Figure 4, the connection states of the switches in the three working states are shown. Figure 5(a) corresponds to the first working state, where only the first battery pack 10 is configured in the first slot 11. After the first battery pack 10 is inserted, the third switch AS3 and the sixth switch AS4 are changed from closed to open, and the fourth switch AS1 and the fifth switch AS2 are changed from open to closed. Therefore, referring to the right side, among the four switches corresponding to the four electrode terminals of the second battery pack 20, although the sixth switch AS4 is open, the fourth switch AS1 and the fifth switch AS2 are closed, and the sixth switch BS4 remains closed, so that the four electrode terminals of the second battery pack 20 are all connected together. Referring to the left side, among the four switches corresponding to the four electrode terminals of the first battery pack 10, only the third switch AS3 is switched to open, but since the other third switch BS3 has not changed, the circuit connection effect corresponding to the four electrode terminals of the first battery pack 10 remains unchanged, and the two battery groups in the first battery pack 10 remain in series, and the first battery pack 10 outputs a voltage of 48V to the outside.

FIG5(b) corresponds to the second working state. Similar to FIG5(a), only the second battery pack 20 is configured in the second slot 12. After the second battery pack 20 is inserted, the third switch BS3 and the sixth switch BS4 are changed from closed to open, and the first switch BS1 and the second switch BS2 are changed from open to closed. Therefore, among the four switches on the right side corresponding to the four electrode terminals of the second battery pack 20, only the third switch BS4 is switched to open, but because the other sixth switch AS4 is unchanged, the two battery groups in the second battery pack 20 remain in series. Among the four switches on the left side corresponding to the four electrode terminals of the first battery pack 10, although the third switch BS3 is opened, the first switch BS1 and the second switch BS2 are changed to closed, and the third switch AS3 remains on, so that the four electrode terminals corresponding to the first battery pack 10 are all connected together, and the second battery pack 20 outputs a voltage of 48V to the outside.

FIG5(c) corresponds to the third working state. The first battery pack 10 and the second battery pack 20 are respectively arranged in the first slot 11 and the second slot 12. After the first battery pack 10 is inserted, the third switch AS3 and the sixth switch AS4 are changed from closed to open, and the fourth switch AS1 and the fifth switch AS2 are changed from open to closed; after the second battery pack 20 is inserted, the third switch BS3 and the sixth switch BS4 are changed from closed to open, and the first switch BS1 and the second switch BS2 are changed from open to closed. Thus, the two battery groups of the first battery pack 10 are connected in parallel, the two battery groups of the second battery pack 20 are connected in parallel, and the first and second battery packs 20 are kept in series, and the output voltage is 48V.

In the above switch settings, the first switch BS1 and the second switch BS2 are used to connect the two battery packs in the battery pack 10 in parallel, and the fourth switch AS1 and the fifth switch AS2 are used to connect the two battery packs in the battery pack 20 in parallel, which can be regarded as parallel switches, and are normally open switches in this embodiment. The two third switches AS3 and BS3 are used to connect the two battery packs in the battery pack 10 in series, and the two sixth switches AS4 and BS4 are used to connect the two battery packs in the battery pack 20 in series, which can be regarded as series switches, and are normally closed switches in this embodiment. In the same circuit, if the series switch and the parallel switch are in the closed conductive state at the same time, a short circuit will occur. Among the four switches that control the first battery pack 10, the two parallel switches BS1 and BS2 are triggered by the second battery pack 20, the series switch BS3 is triggered by the second battery pack 20, and the other series switch AS3 is triggered by the first battery pack 10 itself. Among the four switches controlling the second battery pack 20 , two parallel switches AS1 and AS2 are triggered by the first battery pack 10 , the series switch AS4 is triggered by the first battery pack 10 , and the other series switch BS4 is triggered by the second battery pack 20 .

It can be seen that only when two battery packs are inserted, the two series switches corresponding to each battery pack will be switched to open, and the two parallel switches will be switched to closed and turned on, so that the two battery groups of each battery pack are switched to parallel. If a single battery pack is inserted, although the two parallel switches of the other battery pack will be closed and turned on, due to the lack of the series switch that can only be triggered to open by the other battery pack itself, the circuit corresponding to the other battery pack will be in parallel and series at the same time, that is, the four electrode terminals of the other battery pack are all electrically connected to each other, similar to a short circuit. And due to the lack of insertion of another battery pack, the two parallel switches of the inserted battery pack remain open, and the series switch switched by itself is disconnected, but the series switch switched by the other battery pack remains in series, so the two battery groups of the inserted battery pack remain in series.

The above switch settings can achieve the following functions: the insertion of a single battery pack can make all the electrode terminals of the corresponding other battery pack be electrically connected together, and the single battery pack outputs voltage in a high-voltage state; the insertion of two battery packs can switch each battery pack to a low-voltage state, so that the two battery packs are connected in series to form a high-voltage output together. Each battery pack corresponds to two series switches. Only when the two battery packs are respectively inserted into the corresponding slots can the two series switches be switched to parallel connection, so that the two battery groups in the battery pack are connected in parallel. When a battery pack is already in use and another battery pack needs to be inserted, the tool can be stopped first, and then the other battery pack can be inserted. The two battery packs output a 48V voltage in series.

In this embodiment, all switches are mechanical switches, which need to be triggered by the insertion action of the battery pack.

Implementation II

As shown in FIG6 , the difference between this embodiment and the first embodiment is that an electronic switch is used, and the two series switches in the first embodiment can be combined into one series switch. The first group of control switches for adjusting the connection mode of the four electrodes of the first battery pack 10 includes two parallel switches CS1 and CS2 and one series switch CS3, the parallel switch CS1 connects the first negative terminal 101 and the second negative terminal 103, the parallel switch CS2 connects the first positive terminal 102 and the second positive terminal 104, and the series switch CS3 connects the second negative terminal 103 and the first positive terminal 102. The second group of control switches for adjusting the connection mode of the electrodes of the second battery pack 20 includes two parallel switches DS1 and DS2 and one series switch DS3, the parallel switch DS1 connects the first negative terminal 105 and the second negative terminal 107, the parallel switch DS2 connects the first positive terminal 106 and the second positive terminal 108, and the series switch DS3 connects the second negative terminal 107 and the first positive terminal 106, and the first battery pack 10 and the second battery pack 20 are connected in series. Among them, each parallel switch CS1, CS2, DS1, DS2 is a normally open switch, which is initially in an open state, and each series switch CS3, DS3 is a normally closed switch, which is initially in a closed and conducting state, that is, without any switching of the switches, the first battery pack 10 and the second battery pack 20 can be connected in series, and the two battery groups in each battery pack 10, 20 can be connected in series.

As shown in FIG. 7 , the electric tool 100 is also provided with a microcontroller unit MCU. All switch switching is controlled by the microcontroller unit MCU. Insertion of the first battery pack 10 and the second battery pack 20 will not directly cause switching of any switch. No switch terminals for controlling the switches are provided in the slots 11 and 12 .

As shown in Figure 8(a), after the microcontroller unit MCU is powered on, it will sequentially detect the first voltage between the points A and B at both ends of the first battery pack 10 and the second voltage between the points C and D at both ends of the second battery pack 20. If the first voltage is detected to be 48V and the second voltage is 0V, it means that the power tool 100 is only installed with the first battery pack 10. Corresponding to the first working state mentioned above, the microcontroller unit MCU will close and turn on the parallel switches DS1 and DS2, and keep the series switch DS3 turned on, so that the four electrode terminals of the corresponding second battery pack 20 are all electrically connected to form a short-circuit circuit; the corresponding switches CS1, CS2, and CS3 in the first battery pack 10 are controlled to remain unchanged, that is, the two battery groups in the first battery pack 10 remain connected in series, and the output voltage is 48V.

As shown in Figure 8(b), if the first voltage is detected to be 0V and the second voltage is 48V, it means that the power tool 100 is only installed with the second battery pack 20. Corresponding to the second working state mentioned above, the microcontroller unit MCU will close and turn on CS1 and CS2, and the series switch CS3 will remain turned on to make all the four electrode terminals of the corresponding first battery pack 10 electrically connected to form a short-circuit circuit; the corresponding switches DS1, DS2, and DS3 in the second battery pack 20 remain unchanged, and the two battery groups in the second battery pack 20 remain connected in series, and the output voltage is 48V.

Combined with Figure 8(c), if it is detected that the first voltage and the second voltage are both 48V, it means that the power tool 100 is installed with the first battery pack 10 and the second battery pack 20. Corresponding to the third working state mentioned above, the microcontroller unit MCU will disconnect the series connection CS3 and DS3, and then close the parallel connection CS1, CS2 and DS1, DS2, that is, the two battery packs in each battery pack 10, 20 are switched to parallel connection, and the two battery packs 10, 20 are connected in series, and the overall output voltage is 48V.

Embodiment 3

Referring to FIG9 , this embodiment is similar to the first embodiment, except that all switches in the first embodiment are single-pole single-throw switches, and the double-pole double-throw switches used in this embodiment are replaced with single-pole single-throw switches. The double-pole double-throw is equivalent to including two switches, but the switching of the two switches can be realized synchronously by one trigger.

In this embodiment, two parallel switches ASS1 and BSS1 and two series switches ASS2 and BSS2 are included. The parallel switches ASS1 and BSS1 and the series switches ASS2 and BSS2 are all double-pole double-throw switches. The parallel switch BSS1 is equivalent to the first switch BS1 and the second switch BS1 in the first embodiment, and is respectively connected to the "1-" representing the first negative terminal 101 and the "2-" representing the second negative terminal 103 on the left, the "1+" representing the first positive terminal 102 and the "2+" representing the second positive terminal 104, and is used to connect the two battery groups in the first battery pack 10 in parallel. The parallel switch ASS1 is equivalent to the fourth switch AS1 and the fifth switch AS2 in the first embodiment, and is respectively connected to the "1-" representing the first negative terminal 105 and the "2-" representing the second negative terminal 107 on the right, the "1+" representing the first positive terminal 106 and the "2+" representing the second positive terminal 107, and is used to connect the two battery groups in the second battery pack 20 in parallel.

The series switch ASS2 is equivalent to the third switch AS3 and the sixth switch AS4 in the first embodiment, and is respectively connected to "2-" representing the second negative terminal 107 and "1+" representing the first positive terminal 106, and "2-" representing the second negative terminal 103 and "1+" representing the first positive terminal 102, and is used to respectively control a set of series circuits between the first battery pack 10 and the second battery pack 20. The series switch BSS2 is equivalent to the third switch BS3 and the sixth switch BS4 in the first embodiment, and is connected in the same manner as the series switch ASS2, and is respectively connected to "2-" representing the second negative terminal 107 and "1+" representing the first positive terminal 106, and "2-" representing the second negative terminal 103 and "1+" representing the first positive terminal 102, and is used to control another set of series circuits between the first battery pack 10 and the second battery pack 20. The parallel switches ASS1 and BSS1 are normally open switches and are initially in an open state; the series switches ASS2 and BSS2 are normally closed switches and are initially in a closed and conducting state, that is, when the switches are not switched, the first battery pack 10 and the second battery pack 20 can be connected in series, and the two battery packs in each battery pack 10, 20 can be connected in series, which is the same as in the first embodiment.

As shown in reference figure 10, the first slot 11 accommodating the first battery pack 10 is provided with two switch terminals 13 corresponding to the parallel switch ASS1 and the series switch ASS2 respectively, and the second slot 12 accommodating the second battery pack 20 is provided with two switch terminals (not shown) corresponding to the parallel switch BSS1 and the series switch BSS2 respectively.

As shown in FIG. 11(a), only the first battery pack 10 is inserted into the first slot 11, the series switch ASS2 is switched off, and the parallel switch ASS1 is switched to a closed and conductive state. The parallel switch BSS1 remains open, and the series switch BSS2 remains closed and conductive, so that the four electrode terminals corresponding to the second battery pack 20 are all electrically connected to each other. The specific circuit switching process has been described in detail in the first embodiment, and the relevant contents in the first embodiment can be referred to, and will not be repeated here. The two battery packs in the first battery pack 10 remain in series and output 48V to the outside.

As shown in FIG. 11( b ), only the second battery pack 20 is inserted into the second slot 12, the series switch BSS2 is switched to the open state, and then the parallel switch BSS1 is switched to the closed state. The parallel switch ASS1 remains open, and the series switch ASS2 remains closed and turned on, so that the four electrode terminals of the first battery pack 10 are all electrically connected to each other. As above, this part of the content can refer to the relevant content in the first embodiment. The two battery packs in the second battery pack 20 remain in series and output 48V to the outside.

Referring to FIG. 11(c), the first battery pack 10 is inserted into the first slot 11, the series switch ASS2 is disconnected, and the parallel switch ASS1 is switched to a closed conductive state; at the same time, the second battery pack 20 is inserted into the second slot 12, the series switch BSS2 is disconnected, and the parallel switch BSS1 is switched to a closed conductive state. Thus, the first battery pack 10 and the second battery pack 20 are connected in series, and the two battery packs in each battery pack 10, 20 are connected in parallel, and output 48V to the outside.

Embodiment 4

In the first embodiment, four switch terminals 12 and 22 are set in each slot, and the battery packs 10 and 20 inserted into the slots press these switch terminals 12 and 22 to trigger the corresponding switches. In this embodiment, these switch terminals are cancelled and a mechanical control is adopted instead. The difference between this embodiment and the first and third embodiments lies in the specific triggering method of the switch. The other parts, including the specific circuit principle, the setting method and the switching method of the switch, are the same as those in the first embodiment. Please refer to the relevant content in the first embodiment, and only a brief description is given below.

Referring to FIG. 12 and FIG. 15 , a first male connector 14 is provided in one of the slots. The first male connector 14 includes an insulating body and four electrode terminals fixed on the insulating body, including a first negative terminal 101, a first positive terminal 102, a second negative terminal 103 and a second positive terminal 104, which are respectively connected to the first negative electrode, the second negative electrode, the first positive electrode and the second positive electrode of the first battery pack 10. A second male connector 24 is provided in the other slot. The second male connector 24 includes an insulating body and four electrode terminals fixed on the insulating body, including a first negative terminal 105, a first positive terminal 106, a second negative terminal 107 and a second positive terminal 108, which are respectively connected to the first negative electrode, the second negative electrode, the first positive electrode and the second positive electrode of the second battery pack 20.

As shown in FIG. 4 to FIG. 5 , the electric tool 100 is provided with four control switches for controlling the first battery pack 10, including two parallel switches BS1, BS2 and two series switches AS3, BS3; and four control switches for controlling the second battery pack 20, including two parallel switches AS1, AS2 and two series switches AS4, BS4. The parallel switches BS1, BS2, AS1, AS2 realize parallel control of the battery groups in the battery packs 10, 20 by connecting to the aforementioned electrode terminals, and the series switches AS3, BS3, AS4, BS4 realize series control of the battery groups in the battery packs 10, 20 by connecting to the aforementioned electrode terminals. All the parallel switches BS1, BS2, AS1, AS2 are normally open switches, and all the series switches AS3, BS3, AS4, BS4 are normally closed switches. That is, when each switch is not switched, the first battery pack 10 and the second battery pack 20 can be connected in series, and the two battery groups in each battery pack 10, 20 can be connected in series. The first battery pack 10 controls the switching of the parallel switches AS1, AS2 and the series switches AS3, AS4, and the second battery pack 20 controls the switching of the parallel switches BS1, BS2 and the series switches BS3, BS4. When both battery packs 10, 20 are inserted, the two battery packs of each battery pack 10, 20 are switched in parallel, and the two battery packs 10, 20 jointly output a 48V voltage to the outside. If a single battery pack is inserted, the inserted battery pack outputs a 48V voltage to the outside in the form of two battery packs connected in series. The connection method of each switch and the switch switching process of the power tool 100 in the three working states can be combined with the relevant content in Example 1.

The structure of the linkage switch and the connection status with each electrode terminal will be described in detail below.

Referring to FIG. 12 and FIG. 14 , the electric tool 100 of this embodiment is provided with two linkage switches 3, which are respectively arranged on the inner side of the two slots. The linkage switch 3 is arranged in a cavity on the back side of the slot of the electric tool 100. The linkage switch 3 includes a contact piece 31, a linkage assembly 32, an elastic member 33, a pressure plate assembly 34, a micro button 35 and a plurality of screws 36. The micro button 35 is provided with a head 351 and a rod 352, and the head 351 partially protrudes into the slot through the bottom wall of the corresponding slot to be triggered by the first battery pack 10 or the first battery pack 20. The two linkage switches 3 have the same structure, and the following will be described by taking one linkage switch 3 as an example.

The linkage assembly 32 is arranged roughly parallel to the pressure plate assembly 34, and the elastic member 33 is located between the linkage assembly 32 and the pressure plate assembly 34. The pressure plate assembly 34 and the linkage assembly 32 are respectively provided with accommodating cavities 340 and 320 for accommodating the elastic member 33 to prevent the elastic member 33 from being separated. After the head 351 of the micro-button 35 is compressed, it drives the rod 352 to push the linkage assembly 32 toward the pressure plate assembly 34 and compress the elastic member 33. The linkage assembly 32 is roughly in the shape of a cross, and the electric tool 100 is correspondingly provided with a mounting seat 15, and the mounting seat 15 is provided with a mounting groove 151. The linkage assembly 32 is accommodated in the mounting groove 151 and can slide up and down in the mounting groove 151 (viewed from the placement direction in Figure 14).

As shown in reference to FIG. 15 and FIG. 18 , two contact pieces 31 are respectively provided at opposite ends of the mounting groove 151, wherein the two contact pieces 31 at one end are connected to the first positive terminal 102 and the second negative terminal 103 of the first male connector 14 through wires, and the two contact pieces 31 at the other end are respectively connected to the first positive terminal 106 and the second negative terminal 107 of the second male connector 24 through wires. A first contact point (not numbered) is provided at the other end of each contact piece 31 that is not connected. The linkage assembly 32 includes an insulating substrate 321 and two conductive pieces 322 located at opposite ends of the insulating substrate 321, the conductive pieces 322 are arranged on the first side surface A of the insulating substrate 321 facing the micro-switch button 35, and each conductive piece 322 is provided with two second contacts 323 for simultaneously contacting the first contacts of the two contact pieces 31 located at the same end.

As shown in FIG. 22 , the contact piece 31 electrically connected to the first battery pack 10 and the corresponding conductive piece 322 form the aforementioned series switch AS3 of the first battery pack 10, and the contact piece 31 electrically connected to the second battery pack 20 and the corresponding conductive piece 322 form the aforementioned series switch AS4 of the first battery pack 20. In the initial state, under the action of the elastic member 33, the conductive piece 322 maintains contact with the corresponding two contact pieces 31, so that the series switches AS3 and AS4 form normally closed switches.

Referring to FIGS. 17 to 21 , the pressing plate assembly 34 can be fixed on the screw column 16 around the mounting groove 151 by means of screws 36. The pressing plate assembly 34 includes an insulating plate 341 and four conductive sheets 342 located on the insulating plate 341, which are respectively connected to the four electrode terminals 105, 106, 107, and 108 of the second male connector 24. The conductive sheet 342 is provided with a third contact 343 that passes through the insulating plate 341 and is exposed facing the linkage assembly 32. As shown in FIG. 19 , the linkage assembly 32 is provided with four adapter sheets 324 on the second side surface B facing the pressing plate assembly 34 corresponding to the four conductive sheets 342 of the pressing plate assembly 34, and the two adapter sheets 324 corresponding to the first and second negative terminals 105 and 107 through the two conductive sheets 342 are connected by wires, and the other two adapter sheets 324 corresponding to the first and second positive terminals 106 and 108 through the other two conductive sheets 342 are also connected by wires. As shown in FIG. 19 , each adapter sheet 324 is provided with a fourth contact 325 corresponding to the third contact 343 of the conductive sheet 342. In combination with FIG. 22 , the four conductive sheets 342, the four adapter sheets 324 and the conductive wires together form the parallel switches AS1 and AS2 of the two battery groups of the aforementioned parallel second battery pack 20. In the initial state, under the action of the elastic member 33, the conductive sheet 322 is separated from the corresponding two contact sheets 31, so that the parallel switches AS1 and AS2 form normally open switches. When the first battery pack 10 is inserted into the slot, the micro button 35 is pressed, and the micro button 35 pushes the linkage assembly 32 toward the pressure plate assembly 34 through its drive column 352 extending into the mounting slot 151. During this process, the contact piece 31 and the pressure plate assembly 34 remain stationary, so the contact piece 31 is separated from the conductive piece 322, so that the series switches AS3 and AS4 change from closed to open; the adapter piece 324 of the linkage assembly 32 contacts the corresponding conductive piece 342 on the pressure plate assembly 34, respectively, so that the parallel switches AS1 and AS2 change from open to closed. Therefore, the insertion of the first battery pack 10 can realize the switching control of the parallel switches AS1 and AS2 and the series switches AS3 and AS4. The first battery pack 10 outputs a voltage of 48V. The specific switch state can refer to Figure 5 (a) and Figure 23. In the same way, another linkage switch 3 forms parallel switches BS1 and BS2 and series switches BS3 and BS4. When the second battery pack 20 is inserted into another slot, the parallel switches BS1 and BS2 and the series switches BS3 and BS4 can be fully switched. The second battery pack 20 outputs a voltage of 48V. The specific switch state can refer to Figure 5 (b). If the first battery pack 10 and the second battery pack 20 are inserted at the same time, all switches are switched, and the two battery packs 10 and 20 jointly output a voltage of 48V. The specific switch status can be referred to FIG. 5( c ) and FIG. 24 .

Embodiment 5

In the above-mentioned embodiments 1 to 4, the output state of the battery pack is controlled by a switch. When a single battery pack 10, 20 is inserted, the inserted battery pack 10, 20 forms a high-voltage output; when both battery packs 10, 20 are inserted, the single battery pack 10, 20 forms a low-voltage output, and the two battery packs 10, 20 form a high-voltage output.

As another alternative, referring to FIGS. 25 to 27 , a third battery pack 40 may be provided, wherein a parallel plug seat 50 may be provided inside the third battery pack 40, and the parallel plug seat 50 is provided with two U-shaped parallel terminals 51, which are respectively connected to two electrode plugs 41 of the same polarity in the corresponding two battery packs under the action of a spring 52, so that the two battery packs in the third battery pack 40 are in a parallel state, and the default low-voltage output is achieved. A serial male socket 60 is provided on the power tool 100, and the serial male socket 60 is provided with a protruding insulating column 61 and a serial terminal 62. When the third battery pack 40 is required to be used for work, the insulating column 61 of the serial male socket 60 pushes the extension column 53 of the parallel plug seat 50, so that the parallel terminal 51 is separated from the electrode female terminal 41, and the parallel state of the two battery packs is cancelled, and then the serial terminal 62 of the serial male socket 60 is connected to two of the electrode female terminals 41 of the corresponding two battery packs with different polarities, so that the two battery packs in the third battery pack 40 are in a serial state, and a high-voltage output is formed. Another positive electrode and another negative electrode of the third battery pack 40 that are not in contact with the series terminal 62 are the total positive electrode and the total negative electrode. Each slot of the power tool 100 is provided with two electrode terminals connected to the total positive and the total negative, respectively.

The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "an" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

Terms such as "disposed" and the like appearing in this document may indicate that one component is directly attached to another component or that one component is attached to another component through an intermediate component. Features described in this document in one embodiment may be applied to another embodiment alone or in combination with other features, unless the feature is not applicable in the other embodiment or otherwise specified.

It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

The above electric tool of the present invention is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims (10)

1. An electric tool, provided with four electrode terminals for cooperating with two battery packs of a battery pack, including two positive terminals and two negative terminals, characterized in that: the electric tool is provided with a linkage switch, the linkage switch includes two contact pieces, a pressure plate assembly and a movable linkage assembly, the two contact pieces are connected to corresponding different battery packs, and one of the contact pieces is electrically connected to a positive terminal of one battery pack, and the other contact piece is electrically connected to a negative terminal of another battery pack, the pressure plate assembly is provided with four conductive pieces electrically connected to the four electrode terminals respectively; the linkage assembly is provided with a relative first contact piece and a second contact piece. a side surface and a second side surface, wherein the first side surface is provided with a conducting sheet, and the second side surface is provided with a plurality of adapter sheets; in an initial state, the conducting sheet contacts the two contact sheets, the one positive terminal and the one negative terminal are electrically connected, and at this time, the plurality of adapter sheets are separated from the four conductive sheets; when the linkage assembly is pressed and moves toward the pressure plate assembly, the plurality of adapter sheets contact the four conductive sheets, the two positive terminals are electrically connected, and the two negative terminals are electrically connected, and at this time, the conducting sheet is separated from the two contact sheets, thereby controlling the series-parallel state of the two battery groups in the battery pack. 2. The electric tool according to claim 1 is characterized in that: the plurality of adapter plates include four, which are respectively in contact with the four conductive plates, and are electrically connected between the two adapter plates corresponding to the two positive terminals through the conductive plates, and are electrically connected between the two adapter plates corresponding to the two negative terminals through the conductive plates. 3 . The electric tool according to claim 2 , wherein the linkage assembly further comprises an elastic member disposed between the linkage assembly and the pressure plate assembly, and the elastic member drives the linkage assembly to reset. 4 . The electric tool according to claim 3 , wherein the pressure plate assembly and the linkage assembly are respectively provided with a receiving cavity for accommodating the elastic member. 5. The electric tool according to claim 3 is characterized in that: the electric tool is also provided with a mounting base, the linkage switch is installed on the mounting base, the mounting base is provided with a mounting groove, the contact piece is fixed on the side wall of the mounting base, the pressure plate assembly is fixed to the top of the mounting groove by screws, and the linkage assembly is movably arranged in the mounting groove and is located between the contact piece and the pressure plate assembly. 6. The electric tool according to claim 3, characterized in that: the linkage switch further comprises a micro button, the micro button is provided with a head and a rod, the head is pressed to drive the rod to drive the linkage assembly. 7. An electric tool system, characterized in that: the electric tool system comprises a first battery pack, a second battery pack and the electric tool as described in any one of claims 1 to 5, the electric tool comprises two slots, including a first slot for accommodating the first battery pack and a second slot for accommodating the second battery pack, each slot is provided with four electrode terminals, and the two contact pieces and four conductive pieces of the linkage switch are respectively connected to the corresponding electrode terminals in the second slot. 8. The electric tool system according to claim 7 is characterized in that: the linkage switch also includes a micro button, the micro button is provided with a head and a rod, the head protrudes into the first slot, and when the first battery pack is inserted into the first slot, the linkage assembly is driven to move toward the pressure plate assembly. 9. The electric tool system according to claim 8 is characterized in that: the four electrode terminals include a first positive terminal and a first negative terminal electrically connected to the same battery pack, and a second positive terminal and a second negative terminal electrically connected to another battery pack, wherein two of the contact pieces are electrically connected to the first positive terminal and the second negative terminal, respectively; the linkage component is also provided with two other contact pieces, and the other two contact pieces are respectively connected to the first positive terminal and the second negative terminal in the first slot, and the linkage component is also provided with another conductive piece connecting the other two contact pieces. 10. The electric tool system according to claim 9 is characterized in that: the electric tool is also provided with another linkage switch with the same structure as the linkage switch, the two contact pieces and the four conductive pieces of the other linkage switch are respectively connected to the corresponding electrode terminals in the first slot, the other two contact pieces of the other linkage switch are respectively connected to the first negative terminal and the second positive terminal in the second slot, and the other linkage switch is driven when the second battery pack is inserted into the second slot; the second positive terminal in the first slot remains connected to the first negative terminal in the second slot.