CN220107601U - Battery pack charging and discharging device - Google Patents

Abstract

The utility model discloses a battery pack charging and discharging device, which comprises a shell and a charging and discharging circuit arranged in the shell, wherein a front panel of the shell is provided with a change-over switch for switching charging and discharging states and a battery pack interface for connecting a battery pack to perform charging and discharging operations; the charging and discharging circuit comprises an electronic load circuit for discharging the battery pack, a charging circuit for charging the battery pack, a relay control circuit electrically connected with the change-over switch, and the change-over switch is also used for switching the electronic load circuit and the charging circuit, and the electronic load circuit and the charging circuit are both connected to the battery pack interface. The battery pack charge-discharge maintenance device maintains the battery pack through timely charge-discharge, and simplifies the charge-discharge operation process of the battery pack.

Description

Battery pack charging and discharging device

Technical Field

The utility model relates to the technical field of battery pack charge and discharge maintenance, in particular to a battery pack charge and discharge device.

Background

With the wide application of battery packs for storing electric energy in electric bicycles, electric appliances, and the like, the battery packs are becoming an indispensable part of production and life. The battery pack is continuously accompanied with the charge and discharge process of the battery pack in the use process, and timely charge and discharge is a maintenance method for ensuring the repeated long-term use of the battery pack.

In the prior art, the electric equipment usually works to discharge, namely, the electric equipment is charged and discharged through the actual use process, manual monitoring is needed, and the power supply is required to be turned off after the electric equipment is discharged to a specified voltage. The mode is unfavorable for saving manpower, can not realize automatic control of charging, causes complicated discharging process of the battery pack in the daily maintenance process, and has low efficiency.

For charging, the battery packs can have different voltage types and battery capacities, for example, the battery packs of 12V, 24V and the like can correspond to different battery capacities, and the charger is also expected to adapt to the charging of the battery packs of different types.

Disclosure of Invention

The utility model mainly solves the technical problems of providing a battery pack charging and discharging device, solving the problems of complicated process and low efficiency caused by using electrical equipment to discharge a battery pack in the prior art and adapting to the charging and discharging requirements of various battery packs.

In order to solve the technical problems, the utility model adopts a technical scheme that a battery pack charging and discharging device is used for charging and discharging operations, so that the operation process can be simplified, and the charging and discharging efficiency can be improved. The battery pack charging and discharging device comprises a shell and a charging and discharging circuit arranged in the shell, wherein a change-over switch for switching charging and discharging states is arranged on a front panel of the shell and is used for connecting a battery pack interface for charging and discharging operation of the battery pack.

The charging and discharging circuit comprises an electronic load circuit for discharging the battery pack, a charging circuit for charging the battery pack, a relay control circuit electrically connected with the change-over switch, and the change-over switch is also used for switching the electronic load circuit and the charging circuit, and the electronic load circuit and the charging circuit are both connected to the battery pack interface.

Preferably, the front panel of the casing is provided with an ac input interface, and the charge-discharge circuit is provided with a switching dc power supply electrically connected to the ac input interface, for converting the input ac power into dc power.

Preferably, the relay control circuit comprises a first delay control relay, the positive electrode power supply end of the first delay control relay is connected with the positive electrode end of the switch direct current power supply through a change-over switch, the negative electrode power supply end is connected with the negative electrode end of the switch direct current power supply, the first delay control relay is respectively connected with the load positive electrode end of the electronic load circuit and the positive electrode end of the battery pack interface through a first control end and a second control end, and the internal attraction switch of the relay controls the on-off of the electronic load circuit and the circuit of the battery pack interface.

Preferably, the relay control circuit comprises a second delay control relay, the positive power supply end of the second delay control relay is connected with the positive end of the switch direct current power supply through a change-over switch, the negative power supply end is connected with the negative end of the switch direct current power supply, the second delay control relay is respectively connected with the power supply end of the charging circuit and the second alternating current input end of the switch direct current power supply through a first control end and a second control end, and the suction switch inside the relay controls the on-off of a circuit between the power supply end of the charging circuit and the second alternating current input end of the switch direct current power supply.

Preferably, the relay control circuit comprises a third delay control relay, wherein the positive electrode power supply end of the third delay control relay is connected with the positive electrode end of the switch direct current power supply through a linkage change-over switch which is synchronously switched with the change-over switch, and the negative electrode power supply end is connected with the negative electrode end of the switch direct current power supply; the first delay control port of the third delay control relay is directly connected with the positive terminal of the switching direct current power supply, and the second delay control port is directly connected with the first delay access port of the electronic load circuit; the third delay control relay is used for delaying the energizing of the electronic load circuit.

Preferably, the electronic load circuit comprises six interfaces, the positive power supply end of the electronic load circuit is connected with the positive end of the switch direct current power supply, and the negative power supply end is connected with the negative end of the switch direct current power supply; the load positive end of the electronic load circuit is connected with the first control end of the first delay control relay, and then is connected to the positive end of the battery pack interface through the second control end, and the load negative end of the electronic load circuit is connected with the negative end of the battery pack interface; the first delay access port of the electronic load circuit is connected with the second delay control port of the third delay control relay, and the second delay access port is connected with the negative electrode power supply end of the electronic load circuit.

Preferably, the charging circuit comprises a charger for providing direct-current charging voltage and a charging power supply adjusting module, wherein the positive power supply end of the charger is connected with the first control end of the second delay control relay, the second control end of the second delay control relay is connected with the second alternating-current input end of the switch direct-current power supply, and the negative power supply end of the charger is connected with the first alternating-current input end of the switch direct-current power supply; the positive electrode end of the charger is connected with the positive electrode power supply end of the charging power supply adjusting module, and the negative electrode end of the charger is connected with the negative electrode power supply end of the charging power supply adjusting module.

Preferably, the positive electrode end of the charging power supply adjusting module is connected with the positive electrode end of the battery pack interface, and the negative electrode end of the charging power supply adjusting module is connected with the negative electrode end of the battery pack interface; the charging power supply regulation module further includes a charging current regulation port and a charging voltage regulation port.

Preferably, the electronic load circuit comprises an adjusting circuit, a comparator circuit and a MOS tube circuit, wherein the adjusting circuit comprises a first resistor and a voltage stabilizing diode which are connected in series and used for protecting the circuit, the voltage stabilizing diode is connected with a second resistor and a sliding rheostat capable of adjusting the resistance value in parallel, the adjusting circuit is used for adjusting the value setting of the turn-off voltage of the electronic load circuit, and one end of a sliding vane of the sliding rheostat is used for adjusting the resistance value and is connected to a first interface of a comparator of the comparator circuit through a third resistor; the comparator circuit comprises a comparator and a capacitor connected in parallel between a second interface and a fourth interface of the comparator, the first interface of the comparator is connected with a third resistor, the second interface is connected with the MOS tube circuit through a fifth resistor, the third interface is connected with the negative electrode end of the switch direct current power supply, the fourth interface is connected with the MOS tube circuit through the fourth resistor, and the fifth interface is connected with the positive electrode end of the switch direct current power supply; the MOS tube circuit comprises a control MOS tube and a current limiting resistor, wherein the grid electrode of the control MOS tube is connected with the fourth resistor, the source electrode of the control MOS tube is connected to the negative electrode end of the battery pack interface through the current limiting resistor, and the drain electrode of the control MOS tube is connected to the positive electrode end of the battery pack interface.

Preferably, the first delay control relay and the second delay control relay are delay control relays, the delay control relay comprises a timer chip and a relay, the timer chip comprises seven pins, the first pin is connected with a switch direct-current power supply, the second pin and the sixth pin are trigger input ends and high trigger ends which are connected with each other, the third pin is a threshold output end and is used for controlling the on and off of the relay, the fourth pin is grounded, the fifth pin is a threshold output end, and the seventh pin is a discharge pin; a third capacitor is connected in parallel between the fourth pin and the fifth pin; a sixth resistor is connected in parallel between the sixth pin and the first pin, the sixth resistor is connected with the positive terminal of the second capacitor, and the negative terminal of the second capacitor is grounded; the relay comprises a coil connected between the first interface and the fourth interface, and an actuation switch controlled by the coil and capable of achieving actuation and disconnection, wherein the actuation switch is connected with the third interface and the fifth interface when the relay is released, and is connected with the fifth interface and the second interface when the relay is actuated, the second interface is connected with the battery pack interface, and the fifth interface is connected with the positive electrode power supply end of the electronic load circuit.

The beneficial effects of the utility model are as follows: the utility model discloses a battery pack charging and discharging device, which comprises a shell and a charging and discharging circuit arranged in the shell, wherein a front panel of the shell is provided with a change-over switch for switching charging and discharging states and a battery pack interface for connecting a battery pack to perform charging and discharging operations; the charging and discharging circuit comprises an electronic load circuit for discharging the battery pack, a charging circuit for charging the battery pack, a relay control circuit electrically connected with the change-over switch, and the change-over switch is also used for switching the electronic load circuit and the charging circuit, and the electronic load circuit and the charging circuit are both connected to the battery pack interface. The battery pack charge-discharge maintenance device discharges the battery pack in a mode of replacing electrical equipment by the electronic load circuit, and replaces the original charging process by the combination of the charger and the charging power supply adjusting module, so that the charge-discharge process of the battery pack is simplified, the labor cost is saved, and the function of the battery pack is better maintained by timely charge-discharge and convenient charge-discharge switching.

Drawings

Fig. 1 is a schematic diagram of a battery pack charge and discharge apparatus according to the present utility model;

fig. 2 is a schematic diagram of an internal circuit of a battery pack charging and discharging apparatus according to the present utility model;

FIG. 3 is a schematic view of a front control panel of a battery pack charging and discharging apparatus according to the present utility model;

FIG. 4 is a schematic diagram of an internal circuit of an electronic load circuit of a battery pack charge-discharge device according to the present utility model;

fig. 5 is a schematic diagram of an internal circuit of a delay control relay of a battery pack charge and discharge device according to the present utility model.

Detailed Description

In order that the utility model may be readily understood, a more particular description thereof will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Preferred embodiments of the present utility model are shown in the drawings. This utility model may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items.

As shown in fig. 1, 2 and 3, the battery pack charge and discharge device includes a housing and a charge and discharge circuit provided inside the housing.

As shown in fig. 1, the charge-discharge circuit W4 includes an electronic load circuit 7 for performing a discharge operation on the battery pack, a charge circuit W3 for performing a charge operation on the battery pack, a changeover switch K2 for switching the electronic load circuit 7 and the charge circuit W3, and a relay control circuit W2 electrically connected to the changeover switch K2, the electronic load circuit 7 and the charge circuit W3 being connected to the battery pack interface 8.

Fig. 2 is a detailed internal circuit schematic diagram of the charge and discharge device, and fig. 3 is a schematic diagram of a front panel outside the charge and discharge device.

It should be noted that, as shown in fig. 1 and fig. 2, the charge-discharge circuit inside the battery pack charge-discharge device further includes a protection circuit W1, where the protection circuit W1 includes a fuse F1 and a power switch K1 directly connected to the ac input interface, and the other ends of the two are respectively connected to an undervoltage protector Q1, a power indicator LED1, and an EMI filter L1, and the three are sequentially disposed between the live wire and the neutral wire of the ac input. The power indicator light LED1 is used for indicating whether the circuit is on an ac power supply. The fuse F1 is used for fusing and cutting off current when the circuit is in fault or abnormal and the current is excessively large, so that the fuse F1 plays a role in protecting the safe operation of the circuit. The power switch K1 is used for controlling the on-off of a power supply of the equipment, and the over-under-voltage protector Q1 automatically cuts off the power supply when the voltage of the accessed alternating current power supply is too large or too small, so as to provide protection for the circuit. The EMI filter L1 is used to filter out conducted electromagnetic interference and radiated electromagnetic interference in the circuit.

A switching dc power supply 1 is connected in series after the protection circuit, for converting the input ac power into a first dc power, and stably outputting a dc power with a constant voltage value, for example, a 12V dc power, for supplying the regulated dc power inside the circuit. The device comprises a first alternating current input end 11 and a second alternating current input end 13, which are respectively used for connecting a live wire and a zero wire of alternating current input; the positive terminal 14 of the switching dc power supply 1 outputs a dc positive voltage, and the negative terminal is a ground terminal.

Further, as shown in fig. 2, preferably, the relay control circuit includes a first delay control relay 3, where a positive power supply terminal 31 of the first delay control relay 3 is connected to a positive terminal 14 of the switch dc power supply 1 through a change-over switch K2, a negative power supply terminal 32 is connected to a negative terminal 12 of the switch dc power supply 1, and the first delay control relay 3 is connected to a load positive terminal 75 of the electronic load circuit 7 and a positive terminal of the battery pack interface 8 through a first control terminal 33 and a second control terminal 34, respectively, and controls on/off of a circuit between the load positive terminal 75 of the electronic load circuit 7 and the positive terminal of the battery pack interface 8 through a pull-in switch KM inside the first delay control relay. A discharge indicator LED3 is disposed between the first control terminal 33 and the load positive terminal 75 of the electronic load circuit, and a current meter A1 for displaying current is connected in series between the second control terminal 34 and the battery pack interface 8, so as to display the current level of the battery pack discharge in real time in a discharge state.

Preferably, the relay control circuit includes a second delay control relay 4, the positive power supply end 41 of the second delay control relay 4 is connected with the positive end 14 of the switch direct current power supply 1 through a change-over switch K2, the negative power supply end 42 is connected with the negative end 12 of the switch direct current power supply 1, the second delay control relay 4 is respectively connected with the second alternating current input end 13 of the switch direct current power supply and the power supply end of the charging circuit through a first control end 43 and a second control end 44, and the on-off of the circuit between the power supply end 24 of the charging circuit and the second alternating current input end 13 is controlled through an internal pull-in switch KM.

It should be noted that, the first delay control relay 3 and the second delay control relay 4 both use the chip NE555 as a main chip for generating delay. The corresponding charging or discharging state is switched to through the change-over switch K2, and after the set time is delayed, the two delay relays are closed to be connected with the corresponding discharging or charging circuits. The first delay control relay is electrified when the switch K2 is switched to a discharging state, and after the set delay time is over, the relay switch in the relay is controlled to be attracted under the action of the coil, so that the function of firstly connecting the battery pack and then starting the electronic load circuit to discharge is realized. The second delay control relay is electrified when the change-over switch K2 is switched to a charging state, and is used for controlling the relay switch in the relay to be attracted under the action of the coil, so that the delay switch-on of the direct-current power supply 1 and the charger 2 is realized.

Preferably, the relay control circuit includes a third delay control relay 5, the positive electrode power supply end 52 of the third delay control relay 5 is connected with the positive electrode end 14 of the switch direct current power supply 1 through a linkage change-over switch K21 which is synchronously switched with the change-over switch K2, the negative electrode power supply end 51 is connected with the negative electrode end 12 of the switch direct current power supply 1, when the change-over switch K2 is switched to a discharging state, the linkage change-over switch K21 is also switched on, otherwise, when the change-over switch K2 is switched to a charging state, the linkage change-over switch K21 is switched off; the first delay control port 53 of the third delay control relay is connected with the positive terminal 14 of the switch direct current power supply, and the second delay control port 54 is connected with the first delay access port 71 of the electronic load circuit 7; the third delay control relay 5 is used for delaying the energizing of the electronic load circuit, i.e. delay controlling the switching on between the first delay control port 53 and the second delay control port 54.

It should be noted that, the third delay control relay 5 is a trigger type delay relay, adopts adjustable resistance delay, sets up the power simultaneously and prevents reverse connection protection, and after the electronic load circuit switched on, discharge indicator lamp LED3 flash once indicates that the circular telegram is normal, and the third delay relay does not act at this moment, begins the delay when receiving the trigger signal simultaneously. In the discharging circuit, after the third delay control relay 5 is used for a few seconds, the normally closed contact after the relay is disconnected is used for switching on the starting electronic load circuit 7, so that the effect that the battery pack is firstly connected and then the electronic load circuit 7 is started in a discharging mode is achieved.

Preferably, the electronic load circuit 7 comprises six interfaces, the positive power supply end 74 of the electronic load circuit is connected with the positive end 14 of the switch direct current power supply 1, the negative power supply end 73 is connected with the negative end 12 of the switch direct current power supply 1, and the negative power supply end 73 is also connected with the second delay access port 72; the load positive terminal 75 of the electronic load circuit is connected with the first control terminal 33 of the first delay control relay, connected with the positive terminal of the battery pack interface 8 through the second control terminal 34, and the load negative terminal 76 is connected with the negative terminal of the battery pack interface 8; the first delay access port 71 of the electronic load circuit is connected with the second delay control port 54 of the third delay control relay 5, and a discharge indicator light LED3 is connected in parallel between the load positive terminal 75 and the load negative terminal 76 and used for indicating the device to enter a discharge state.

Preferably, the charging circuit comprises a charger 2 for providing a dc charging voltage and a charging power supply regulation module 6, the charger 2 being operative to convert the ac power into a second dc power for charging the battery, the second dc power being primarily used for dc charging the battery. The positive electrode power supply end 24 of the charger 2 is connected with the second alternating current input end 13 of the switch direct current power supply, and the negative electrode power supply end 23 of the charger is connected with the first alternating current input end 11 of the switch direct current power supply; the positive electrode terminal 22 of the charger is connected with the positive electrode power supply terminal 61 of the charging power supply regulating module 6, and the negative electrode terminal 21 of the charger 2 is connected with the negative electrode power supply terminal 62 of the charging power supply regulating module 6.

Preferably, the positive terminal 63 of the charging power supply adjusting module 6 is connected with the positive terminal of the battery pack interface 8 through the ammeter A1, and the negative terminal 64 of the charging power supply adjusting module 6 is connected with the negative terminal of the battery pack interface 8; the charging power supply adjusting module further comprises a charging current adjusting port 65 and a charging voltage adjusting port 66, and the charging current and the charging voltage can be adjusted through the front panel of the casing, so that the charging power supply adjusting module can adapt to charging of different types of battery packs, and a charging indicator light LED2 is connected in parallel between the positive electrode end 63 and the negative electrode end 64 of the charging power supply adjusting module and is used for indicating that the device enters a charging state.

The charging power supply regulating module 6 can realize the function of under-voltage and over-voltage protection in the charging circuit. The charging power supply regulating module may be provided with an upper limit voltage Vu and a lower limit voltage Vn, and the charging machine 2 is configured to start charging the battery pack when the battery pack voltage is less than or equal to the lower limit voltage Vn, and to disconnect the charging power supply regulating module when the battery pack voltage is greater than or equal to the upper limit voltage Vu, so that charging is completed. The circuit can be realized, when the voltage of the battery pack is lower than the lower limit voltage Vn, the battery pack is directly and automatically charged after discharging, and when the voltage of the battery pack is higher than the upper limit voltage Vu, the charging is automatically stopped, so that the battery pack is prevented from being overcharged.

As shown in fig. 3, the front panel of the charge-discharge maintenance device of the present utility model includes a power indicator LED1 for indicating on-off of a circuit, an interface for a fuse F1 of a protection circuit, a power switch K1 for controlling on-off of a circuit, an ac input interface 9 for switching in 220V ac, a change-over switch K2 of a switch change-over circuit for switching in charge or discharge, a charging current adjusting port 65 and a charging voltage adjusting port 66 for adjusting a charging current and voltage of an adjusting device, a battery pack interface 8 for switching in a battery pack, an indicator LED2 and LED3 for indicating a charging state or a discharging state of a circuit, and a ammeter A1 and a voltmeter V1 for displaying current and voltage parameters of a battery pack.

Referring to fig. 2, it should be noted that, the ammeter A1 is connected in series to a line commonly connected to the electronic load circuit 7, the charging power supply adjusting module 6 and the battery pack interface 8, and is used for displaying charging or discharging current of the battery pack, and the voltmeter V1 is connected in parallel to two ends of the battery pack interface 8, and is used for determining a discharging or charging voltage state by detecting voltages of two ends of the battery pack in real time.

As shown in fig. 4, the electronic load circuit comprises an adjusting circuit, a comparator circuit and a MOS tube circuit, wherein the adjusting circuit comprises a first resistor R1 and a zener diode U2 which are connected in series and are used for protecting the circuit, two ends of the zener diode are connected in parallel with a second resistor R2 and a sliding rheostat Rp with adjustable resistance value, the sliding rheostat Rp is used for setting the value of the turn-off voltage of the electronic load circuit, and one end of a sliding sheet of which the resistance value is regulated by the sliding rheostat Rp is connected to a first interface of a comparator U1A of the comparator circuit through a third resistor R3; the comparator circuit comprises a comparator U1A and a first capacitor C1 connected in parallel between a second interface and a fourth interface of the comparator, wherein the first interface of the comparator is connected with a third resistor R3, the second interface is connected with the MOS tube circuit through a fifth resistor R5, the third interface is connected with the negative electrode 12 of the switch direct current power supply 1 as a negative electrode power supply end 73 of the electronic load circuit, the fourth interface is connected with the MOS tube circuit through a fourth resistor R4, and the fifth interface is connected with the positive electrode 14 of the switch direct current power supply 1 as a positive electrode power supply end 74 of the electronic load circuit; the MOS tube circuit comprises a control MOS tube and a current limiting resistor Rs, the grid electrode of the control MOS tube is connected with a fourth resistor R4, the source electrode of the control MOS tube is connected to the negative electrode end of the battery pack interface 8 through the current limiting resistor Rs, and the drain electrode of the control MOS tube is connected to the positive electrode end of the battery pack interface 8.

Interfaces 71-76 of the electronic load circuit in fig. 4 correspond to interfaces 71-76 of the electronic load circuit in fig. 2, respectively. Specifically, the interface 71 of the electronic load circuit is a first delay access port of the electronic load, and is connected to a second delay control port of the third delay control relay, the interface 72 is a second delay access port of the electronic load, the interface 73 is a negative power supply end of the electronic load, and the interface 72 and the interface 73 are directly connected for common grounding. The interface 74 is connected to the positive terminal 14 of the switching dc power supply 1, the interface 75 is connected to the first control terminal 33 of the first delay control relay 3, the second control terminal 34 is connected to the positive terminal of the battery pack interface 8, and the interface 76 is connected to the negative terminal of the battery pack interface 8.

Preferably, the electronic load circuit 7 internally comprises an adjusting knob for setting the turn-off voltage, and the adjusting knob adjusts the turn-off voltage of the battery pack by adjusting the resistance value of the slide rheostat Rp connected into the circuit, so as to be suitable for the battery packs with different specifications.

As shown in fig. 5, a delay control circuit is arranged in the delay control relay, and the delay control circuit comprises a timer chip and a relay, wherein the timer chip NE555DR comprises seven pins, the first pin is connected with the switch direct current power supply 1, the second pin and the sixth pin are trigger input terminals TRIG and high trigger terminals THRES which are mutually connected, the third pin is a threshold output terminal OUT and is used for controlling the on and off of the relay, the fourth pin is grounded, the fifth pin is a threshold output terminal COUT, and the seventh pin is a discharge pin DISCH; a third capacitor C3 is connected in parallel between the fourth pin and the fifth pin; a sixth resistor R6 is connected in parallel between the sixth pin and the first pin, the sixth resistor R6 is connected with the positive terminal of the second capacitor C2, and the negative terminal of the second capacitor C2 is grounded; the relay comprises a coil connected between a first interface and a fourth interface, and an attracting switch KM which is controlled by the coil and can realize attracting and disconnecting, wherein the attracting switch KM is connected with a third interface and a fifth interface when the relay is released, and is connected with the fifth interface and the second interface when the relay is attracted.

It should be noted that, the first delay control relay 3 and the second delay control relay 4 are both delay control relays, where, as shown in fig. 5, for the first delay control relay 3, a fifth interface of the pull-in switch KM of the relay portion is connected to the load positive terminal 75 of the electronic load circuit 7, and a third interface is connected to the battery pack interface 8; the internal structure of the second delay control relay is referred to fig. 5, and will not be described again.

The foregoing is only illustrative of the present utility model and is not to be construed as limiting the scope of the utility model, and all equivalent structural changes made by the present utility model and the accompanying drawings, or direct or indirect application in other related technical fields, are included in the scope of the present utility model.

Claims (10)

1. The battery pack charging and discharging device comprises a shell and a charging and discharging circuit arranged in the shell, and is characterized in that a change-over switch for switching charging and discharging states is arranged on a front panel of the shell, and a battery pack interface for connecting a battery pack to perform charging and discharging operations is arranged on the front panel of the shell;

the charging and discharging circuit comprises an electronic load circuit used for discharging the battery pack, a charging circuit used for charging the battery pack, and a relay control circuit electrically connected with the change-over switch, wherein the change-over switch is also used for switching the electronic load circuit and the charging circuit, and the electronic load circuit and the charging circuit are both connected to the battery pack interface.

2. The battery pack charge and discharge device according to claim 1, wherein the front panel of the casing is provided with an ac input interface, and the charge and discharge circuit is provided with a switching dc power supply electrically connected to the ac input interface for converting the input ac power into dc power.

3. The battery pack charging and discharging device according to claim 2, wherein the relay control circuit comprises a first delay control relay, a positive power supply end of the first delay control relay is connected with a positive end of the switch direct current power supply through the change-over switch, a negative power supply end of the first delay control relay is connected with a negative end of the switch direct current power supply, the first delay control relay is connected with a load positive end of the electronic load circuit and a positive end of the battery pack interface through a first control end and a second control end respectively, and an internal attraction switch of the first delay control relay controls on-off of the electronic load circuit and the circuit of the battery pack interface.

4. The battery pack charging and discharging device according to claim 3, wherein the relay control circuit comprises a second delay control relay, a positive power supply end of the second delay control relay is connected with a positive end of the switch direct current power supply through the change-over switch, a negative power supply end of the second delay control relay is connected with a negative end of the switch direct current power supply, the second delay control relay is respectively connected with a power supply end of the charging circuit and a second alternating current input end of the switch direct current power supply through a first control end and a second control end, and an internal attraction switch of the relay controls on-off of a circuit between the power supply end of the charging circuit and the second alternating current input end of the switch direct current power supply.

5. The battery pack charging and discharging device according to claim 3, wherein the relay control circuit comprises a third delay control relay, the positive electrode power supply end of the third delay control relay is connected with the positive electrode end of the switch direct current power supply through a linkage change-over switch which is synchronously switched with the change-over switch, and the negative electrode power supply end is connected with the negative electrode end of the switch direct current power supply; the first delay control port of the third delay control relay is directly connected with the positive end of the switching direct current power supply, and the second delay control port is directly connected with the first delay access port of the electronic load circuit; the third delay control relay is used for delaying the power-on of the electronic load circuit.

6. The battery pack charging and discharging device according to claim 5, wherein the electronic load circuit comprises six interfaces, a positive power supply terminal of the electronic load circuit is connected with a positive terminal of the switching direct current power supply, and a negative power supply terminal is connected with a negative terminal of the switching direct current power supply; the load positive electrode end of the electronic load circuit is connected with the first control end of the first delay control relay, and then is connected to the positive electrode end of the battery pack interface by the second control end, and the load negative electrode end of the electronic load circuit is connected with the negative electrode end of the battery pack interface; the first delay access port of the electronic load circuit is connected with the second delay control port of the third delay control relay, and the second delay access port is connected with the negative electrode power supply end of the electronic load circuit.

7. The battery pack charging and discharging device according to claim 6, wherein the charging circuit comprises a charger for providing a direct current charging voltage and a charging power supply adjusting module, the positive electrode power supply end of the charger is connected with the first control end of the second delay control relay, the second control end of the second delay control relay is connected with the second alternating current input end of the switch direct current power supply, and the negative electrode power supply end of the charger is connected with the first alternating current input end of the switch direct current power supply; the positive electrode end of the charger is connected with the positive electrode power supply end of the charging power supply adjusting module, and the negative electrode end of the charger is connected with the negative electrode power supply end of the charging power supply adjusting module.

8. The battery pack charging and discharging device according to claim 7, wherein the positive terminal of the charging power supply adjusting module is connected to the positive terminal of the battery pack interface, and the negative terminal of the charging power supply adjusting module is connected to the negative terminal of the battery pack interface; the charging power supply regulation module further comprises a charging current regulation port and a charging voltage regulation port.

9. The battery pack charge-discharge device according to claim 6, wherein the electronic load circuit comprises a regulating circuit, a comparator circuit and a MOS transistor circuit, the regulating circuit comprises a first resistor and a zener diode connected in series for protecting the circuit, wherein the zener diode is connected in parallel with a second resistor and a sliding rheostat capable of adjusting a resistance value, the sliding piece end of the sliding piece is connected to the first interface of the comparator circuit through a third resistor; the comparator circuit comprises a comparator and a capacitor connected in parallel between a second interface and a fourth interface of the comparator, wherein the first interface of the comparator is connected with a third resistor, the second interface is connected with the MOS tube circuit through a fifth resistor, the third interface is connected with the negative electrode end of the switch direct current power supply, the fourth interface is connected with the MOS tube circuit through the fourth resistor, and the fifth interface is connected with the positive electrode end of the switch direct current power supply; the MOS tube circuit comprises a control MOS tube and a current limiting resistor, wherein a grid electrode of the control MOS tube is connected with a fourth resistor, a source electrode of the control MOS tube is connected to a negative electrode end of the battery pack interface through the current limiting resistor, and a drain electrode of the control MOS tube is connected to a positive electrode end of the battery pack interface.

10. The battery pack charging and discharging device according to claim 4, wherein the first delay control relay and the second delay control relay are delay control relays, the battery pack charging and discharging device comprises a timer chip and a relay, the timer chip comprises seven pins, the first pin is connected with a switch direct-current power supply, the second pin and the sixth pin are a trigger input end and a high trigger end which are connected with each other, the third pin is a threshold output end and used for controlling the on and off of the relay, the fourth pin is grounded, the fifth pin is a threshold output end, and the seventh pin is a discharging pin; a third capacitor is connected in parallel between the fourth pin and the fifth pin; a sixth resistor is connected in parallel between the sixth pin and the first pin, the sixth resistor is connected with the positive electrode end of the second capacitor, and the negative electrode end of the second capacitor is grounded; the relay comprises a coil connected between a first interface and a fourth interface, and an actuation switch controlled by the coil to realize actuation and disconnection, wherein the actuation switch is connected with a third interface and a fifth interface when the relay is released, and is connected with the fifth interface and a second interface when the relay is actuated, wherein the second interface is connected with a battery pack interface, and the fifth interface is connected with an anode power supply end of an electronic load circuit.