Battery polarity switching circuit and device in charge and discharge test

Abstract

The utility model is applicable to the field of battery testing, and provides a battery polarity switching circuit and device in a charge and discharge test, and the battery polarity switching circuit in the charge and discharge test comprises an MOS tube Q1, an MOS tube Q2, an MOS tube Q3, an MOS tube Q4, an MOS tube Q5, an MOS tube Q6, an MOS tube Q7, an MOS tube Q8, a first terminal P1, a second terminal P2 and a battery BAT. The MOS tube Q1 and the MOS tube Q2 form an anti-backflow circuit; the MOS tube Q3 and the MOS tube Q4 form an anti-backflow circuit; the MOS tube Q5 and the MOS tube Q6 form an anti-backflow circuit; the MOS tube Q7 and the MOS tube Q8 form anti-backflow circuits, and the four anti-backflow circuits are used for switching the polarity of the battery in the charging and discharging test. The problem that the current of the battery flows backward in the charging and discharging test process is solved.

Description

Technical Field

[0001] The utility model belongs to the field of battery testing, and particularly relates to a battery polarity switching circuit and device in charge and discharge testing. Background Art

[0002] As an indispensable energy storage device for modern electronic devices and electric vehicles, the performance and safety of batteries are crucial to the reliability of the entire system. To ensure the performance and safety of batteries, before leaving the factory, batteries need to undergo multiple safety tests, such as charge and discharge tests, battery cycle tests, safety performance tests, etc.

[0003] Currently, for the battery polarity switching circuit in charge and discharge testing, a method of using an H-bridge circuit composed of 4 MOS transistors to switch the battery polarity is generally adopted.

[0004] Due to the presence of body diodes in MOS transistors, reverse current flow will occur between the drain and source of MOS transistors under the action of the battery. Therefore, this method has the problem of reverse current pouring of the battery during the charge and discharge test. Summary of the Utility Model

[0005] The purpose of the embodiments of the utility model is to provide a battery polarity switching circuit in charge and discharge testing, aiming to solve the problem of reverse current pouring of the battery during the charge and discharge test.

[0006] The embodiments of the utility model are implemented as follows. A battery polarity switching circuit in charge and discharge testing includes: MOS transistor Q1, MOS transistor Q2, MOS transistor Q3, MOS transistor Q4, MOS transistor Q5, MOS transistor Q6, MOS transistor Q7, MOS transistor Q8, first terminal P1, second terminal P2, and battery BAT;

[0007] The D pole of the MOS transistor Q1 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS transistor Q2, and is used to form an anti-reverse current circuit with the MOS transistor Q2 to switch the polarity of the battery during the charge and discharge test;

[0008] The D pole of the MOS transistor Q2 is connected to the positive pole of the battery BAT;

[0009] The D pole of the MOS transistor Q3 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS transistor Q4, and is used to form an anti-reverse current circuit with the MOS transistor Q4 to switch the polarity of the battery during the charge and discharge test;

[0010] The D pole of the MOS transistor Q4 is connected to the second terminal P2;

[0011] The D pole of the MOS transistor Q5 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS transistor Q6, which is used to form an anti-backflow circuit with the MOS transistor Q6 to switch the polarity of the battery during the charge and discharge test;

[0012] The D pole of the MOS transistor Q6 is connected to the positive pole of the battery BAT;

[0013] The D pole of the MOS transistor Q7 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS transistor Q8, which is used to form an anti-backflow circuit with the MOS transistor Q8 to switch the polarity of the battery during the charge and discharge test;

[0014] The D pole of the MOS transistor Q8 is connected to the second terminal P2.

[0015] Preferably, the battery polarity switching circuit during the charge and discharge test further includes a power isolator U1, an opto-isolator U5, and a resistor R8;

[0016] The IN+ interface of the power isolator U1 is connected to the output terminal of the power supply module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U5 through the resistor R8, and the G interface is connected to the S pole of the MOS transistor Q1;

[0017] The anode of the opto-isolator U5 is connected to the first interface of the control module, the cathode is connected to the second interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q1 and the G pole of the MOS transistor Q2.

[0018] Preferably, the battery polarity switching circuit during the charge and discharge test further includes a power isolator U4, an opto-isolator U8, and a resistor R11;

[0019] The IN+ interface of the power isolator U4 is connected to the output terminal of the power supply module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U8 through the resistor R11, and the G interface is connected to the S pole of the MOS transistor Q3;

[0020] The anode of the opto-isolator U8 is connected to the second interface of the control module, the cathode is connected to the third interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q3 and the G pole of the MOS transistor Q4.

[0021] Preferably, the battery polarity switching circuit during the charge and discharge test further includes a power isolator U2, an opto-isolator U6, and a resistor R9;

[0022] The IN+ interface of the power isolator U2 is connected to the output terminal of the power module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U6 through the resistor R9, and the G interface is connected to the S pole of the MOS transistor Q5;

[0023] The anode of the opto-isolator U6 is connected to the fourth interface of the control module, the cathode is connected to the fifth interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q5 and the G pole of the MOS transistor Q6.

[0024] Preferably, the battery polarity switching circuit in the charge and discharge test further includes a power isolator U3, an opto-isolator U7, and a resistor R10;

[0025] The IN+ interface of the power isolator U3 is connected to the output terminal of the power module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U7 through the resistor R10, and the G interface is connected to the S pole of the MOS transistor Q7;

[0026] The anode of the opto-isolator U7 is connected to the first interface of the control module, the cathode is connected to the fourth interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q7 and the G pole of the MOS transistor Q8.

[0027] Preferably, the MOS transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are N-MOS transistors.

[0028] Another object of the embodiment of the present invention is a battery polarity switching device in a charge and discharge test. The battery polarity switching device in the charge and discharge test includes a test circuit and a battery box;

[0029] The test circuit includes the above-mentioned battery polarity switching circuit in the charge and discharge test;

[0030] The battery box is connected to the test circuit and is used for placing a battery.

[0031] A battery polarity switching circuit in a charge and discharge test provided by an embodiment of the present invention has the following beneficial effects:

[0032] The first anti-backflow circuit is composed of MOS transistor Q1 and MOS transistor Q2, the second anti-backflow circuit is composed of MOS transistor Q3 and MOS transistor Q4, the third anti-backflow circuit is composed of MOS transistor Q5 and MOS transistor Q6, and the fourth anti-backflow circuit is composed of MOS transistor Q7 and MOS transistor Q8. By controlling the four anti-backflow circuits, the polarity of the battery in the charge and discharge test can be switched. When the first anti-backflow circuit and the second anti-backflow circuit are turned on, MOS transistors Q6 and Q7 are turned off to prevent the current of the battery from entering the third anti-backflow circuit and the fourth anti-backflow circuit; when the third anti-backflow circuit and the fourth anti-backflow circuit are turned on, MOS transistors Q2 and Q3 are turned off to prevent the current of the battery from entering the first anti-backflow circuit and the second anti-backflow circuit. This solves the problem of current backflow of the battery during the charge and discharge test. Description of the Drawings

[0033] Figure 1 The figure is a circuit diagram of a battery polarity switching circuit in a charge and discharge test provided by an embodiment of the present invention. Detailed Implementation Modes

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] The following describes the specific implementation of the present invention in detail with reference to specific embodiments.

[0036] As Figure 1 shown, the figure is a circuit diagram of a battery polarity switching circuit in a charge and discharge test provided by an embodiment of the present invention, including: MOS transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, first terminal P1, second terminal P2, and battery BAT;

[0037] The D pole of the MOS transistor Q1 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS transistor Q2, and is used to form an anti-backflow circuit with the MOS transistor Q2 to switch the polarity of the battery during the charge and discharge test;

[0038] The D pole of the MOS transistor Q2 is connected to the positive pole of the battery BAT;

[0039] The D pole of the MOS transistor Q3 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS transistor Q4, and is used to form an anti-backflow circuit with the MOS transistor Q4 to switch the polarity of the battery during the charge and discharge test;

[0040] The D pole of the MOS transistor Q4 is connected to the second terminal P2;

[0041] The D pole of the MOS transistor Q5 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS transistor Q6, and is used to form an anti-backflow circuit with the MOS transistor Q6 to switch the polarity of the battery during the charge and discharge test;

[0042] The D pole of the MOS transistor Q6 is connected to the positive pole of the battery BAT;

[0043] The D pole of the MOS transistor Q7 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS transistor Q8, and is used to form an anti-backflow circuit with the MOS transistor Q8 to switch the polarity of the battery during the charge and discharge test;

[0044] The D pole of the MOS transistor Q8 is connected to the second terminal P2.

[0045] In the embodiment of the present invention, the positive and negative poles of the test voltage are connected to the first terminal P1 and the second terminal P2. The test voltage refers to the input voltage to the battery BAT. The test voltage is used for the charge and discharge test of the battery BAT. The test voltage depends on the specifications of the battery BAT.

[0046] In the embodiment of the present invention, the MOS transistors Q1 and Q2 form a first anti-backflow circuit, the MOS transistors Q3 and Q4 form a second anti-backflow circuit, the MOS transistors Q6 and Q7 form a third anti-backflow circuit, and the MOS transistors Q7 and Q8 form a fourth anti-backflow circuit. The switching actions of the MOS transistors in the first anti-backflow circuit and the second anti-backflow circuit are synchronized. The switching actions of the MOS transistors in the third anti-backflow circuit and the fourth anti-backflow circuit are synchronized. The switching actions of the MOS transistors in the first anti-backflow circuit, the second anti-backflow circuit and the MOS transistors in the third anti-backflow circuit, the fourth anti-backflow circuit are opposite.

[0047] In the embodiment of the present utility model, if the first terminal P1 is connected to the positive pole of the test voltage and the second terminal P2 is connected to the negative pole of the test voltage, that is, a positive voltage is applied to the first terminal P1. When the MOS transistor Q1 and the MOS transistor Q3 are turned on, the MOS transistor Q2 and the MOS transistor Q4 remain turned on due to the body diode. The positive current flows into from the first terminal P1, passes through the MOS transistor Q1 and the MOS transistor Q2, and reaches the positive pole of the battery BAT. Then it flows from the negative pole of the battery BAT, passes through the MOS transistor Q3 and the MOS transistor Q4, and reaches the second terminal P2. At this time, the battery BAT is in the charging state. Since the MOS transistor Q5, the MOS transistor Q6, the MOS transistor Q7, and the MOS transistor Q8 are in the cut-off state, the test current of the first terminal P1 cannot pass through the third anti-backflow circuit and the fourth anti-backflow circuit, and the current of the battery BAT cannot flow into the third anti-backflow circuit and the fourth anti-backflow circuit. On the contrary, when the MOS transistor Q5 and the MOS transistor Q7 are turned on, the MOS transistor Q6 and the MOS transistor Q8 remain turned on due to the body diode. The positive current flows into from the first terminal P1, passes through the MOS transistor Q5 and the MOS transistor Q6, and reaches the negative pole of the battery BAT. Then it flows from the positive pole of the battery BAT, passes through the MOS transistor Q7 and the MOS transistor Q8, and reaches the second terminal P2. At this time, the battery BAT is in the discharging state. Since the MOS transistor Q1, the MOS transistor Q2, the MOS transistor Q3, and the MOS transistor Q4 are in the cut-off state, the test current of the second terminal P2 cannot pass through the first anti-backflow circuit and the second anti-backflow circuit, and the current of the battery BAT will not flow into the first anti-backflow circuit and the second anti-backflow circuit.

[0048] In the embodiment of the present utility model, if the first terminal P1 is connected to the negative pole of the test voltage and the second terminal P2 is connected to the positive pole of the test voltage, that is, a positive voltage is applied to the second terminal P2. In the charging state, the third anti-backflow circuit and the fourth anti-backflow circuit are turned on, and the first anti-backflow circuit and the second anti-backflow circuit are cut off; in the discharging state, the first anti-backflow circuit and the second anti-backflow circuit are turned on, and the third anti-backflow circuit and the fourth anti-backflow circuit are cut off.

[0049] In the embodiment of the present utility model, similarly, when the first terminal P1 and the second terminal P2 are connected to the positive and negative poles of the load, that is, when the battery BAT is used to provide electrical energy, the battery polarity switching circuit in the charge and discharge test can also play the role of battery polarity switching, that is, it is not necessary to determine the positive and negative poles of the load to correctly switch the polarity of the battery to adapt to the polarity of the load.

[0050] A battery polarity switching circuit in charge and discharge tests provided by the present utility model forms a first anti-backflow circuit through MOS transistors Q1 and Q2, a second anti-backflow circuit through MOS transistors Q3 and Q4, a third anti-backflow circuit through MOS transistors Q5 and Q6, and a fourth anti-backflow circuit through MOS transistors Q7 and Q8. By controlling the four anti-backflow circuits, the battery polarity in charge and discharge tests is switched. When the first anti-backflow circuit and the second anti-backflow circuit are turned on, MOS transistors Q6 and Q7 are turned off to prevent the current of the battery from entering the third anti-backflow circuit and the fourth anti-backflow circuit; when the third anti-backflow circuit and the fourth anti-backflow circuit are turned on, MOS transistors Q2 and Q3 are turned off to prevent the current of the battery from entering the first anti-backflow circuit and the second anti-backflow circuit. This solves the problem of current backflow of the battery during the charge and discharge test.

[0051] As Figure 1 shown, as a preferred embodiment of the present utility model, the battery polarity switching circuit in the charge and discharge test further includes a power isolator U1, an opto-isolator U5, and a resistor R8;

[0052] The IN+ interface of the power isolator U1 is connected to the output terminal of the power module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U5 through the resistor R8, and the G interface is connected to the S pole of the MOS transistor Q1;

[0053] The anode of the opto-isolator U5 is connected to the first interface of the control module, the cathode is connected to the second interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q1 and the G pole of the MOS transistor Q2.

[0054] In the embodiment of the present utility model, the power module inputs a +15V DC voltage, and this DC power supply is used to provide a high level for the MOS transistors Q1 and Q2.

[0055] In the embodiment of the present utility model, the control module can be an MCU chip or a switch.

[0056] In the embodiment of the present utility model, the power isolator U1 and the opto-isolator U5 form a first isolation circuit, and the first isolation circuit electrically isolates the control module and the first anti-backflow circuit, ensuring the safety when the MOS transistor is switched on and off.

[0057] In the embodiment of the present utility model, it further includes capacitors and resistors required for other constituent circuits.

[0058] In the embodiment of the present utility model, when the anode and cathode of the optoelectronic isolator U5 are conducting, the emitter and collector are also conducting. At this time, the voltage of V+ of the power supply isolator U1 is output to the G poles of the MOS transistors Q1 and Q2, and the MOS transistors Q1 and Q2 are conducting. The positive current can flow from the first terminal P1 to the positive pole of the battery BAT.

[0059] As Figure 1 shown, as a preferred embodiment of the present utility model, the battery polarity switching circuit in the charge and discharge test further includes a power supply isolator U4, an optoelectronic isolator U8, and a resistor R11;

[0060] The IN+ interface of the power supply isolator U4 is connected to the output terminal of the power supply module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the optoelectronic isolator U8 through the resistor R11, and the G interface is connected to the S pole of the MOS transistor Q3;

[0061] The anode of the optoelectronic isolator U8 is connected to the second interface of the control module, the cathode is connected to the third interface of the control module, and the emitter is connected to the G poles of the MOS transistor Q3 and the MOS transistor Q4.

[0062] In the embodiment of the present utility model, the power supply isolator U4 and the optoelectronic isolator U8 form a second isolation circuit. The second isolation circuit electrically isolates the control module and the second anti-backflow circuit, ensuring the safety when the MOS transistor is switched on and off.

[0063] In the embodiment of the present utility model, it further includes capacitors and resistors required for other constituent circuits.

[0064] In the embodiment of the present utility model, when the anode and cathode of the optoelectronic isolator U5 are conducting, the emitter and collector are also conducting. At this time, the voltage of V+ of the power supply isolator U4 is output to the G poles of the MOS transistor Q3 and the MOS transistor Q4, and the MOS transistors Q3 and Q4 are conducting. The negative pole of the battery BAT is conducting to the second terminal P2. Combining with the conduction of the MOS transistors Q1 and Q2, the charging test of the battery BAT is realized.

[0065] In the embodiment of the present utility model, when the first interface and the second interface of the control module are connected, and the second interface and the third interface are connected, the battery can be subjected to a charging test. As Figure 1 shown, the first interface is KV, the second interface is D1, and the third interface is CA.

[0066] As Figure 1 shown, as a preferred embodiment of the present utility model, the battery polarity switching circuit in the charge and discharge test further includes a power supply isolator U2, an optoelectronic isolator U6, and a resistor R9;

[0067] The IN+ interface of the power isolator U2 is connected to the output terminal of the power module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U6 through the resistor R9, and the G interface is connected to the S pole of the MOS transistor Q5;

[0068] The anode of the opto-isolator U6 is connected to the fourth interface of the control module, the cathode is connected to the fifth interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q5 and the G pole of the MOS transistor Q6.

[0069] In the embodiment of the present invention, the power isolator U2 and the opto-isolator U6 form a third isolation circuit, and the third isolation circuit electrically isolates the control module and the third anti-backflow circuit, ensuring the safety during the on-off switching of the MOS transistor.

[0070] In the embodiment of the present invention, it also includes capacitors and resistors required for other circuit components.

[0071] In the embodiment of the present invention, when the anode and cathode of the opto-isolator U6 are conducting, the emitter and collector are also conducting. At this time, the voltage of V+ of the power isolator U3 is output to the G poles of the MOS transistor Q5 and the MOS transistor Q6, and the MOS transistors Q5 and Q6 are conducting. The positive current can flow from the first terminal P1 to the negative pole of the battery BAT.

[0072] As Figure 1 shown, as a preferred embodiment of the present invention, the battery polarity switching circuit in the charge and discharge test further includes a power isolator U3, an opto-isolator U7, and a resistor R10;

[0073] The IN+ interface of the power isolator U3 is connected to the output terminal of the power module, the IN- interface is connected to the ground wire, the V+ interface is connected to the collector of the opto-isolator U7 through the resistor R10, and the G interface is connected to the S pole of the MOS transistor Q7;

[0074] The anode of the opto-isolator U7 is connected to the first interface of the control module, the cathode is connected to the fourth interface of the control module, and the emitter is connected to the G pole of the MOS transistor Q7 and the G pole of the MOS transistor Q8.

[0075] In the embodiment of the present invention, the power isolator U3 and the opto-isolator U7 form a fourth isolation circuit, and the fourth isolation circuit electrically isolates the control module and the fourth anti-backflow circuit, ensuring the safety during the on-off switching of the MOS transistor.

[0076] In the embodiment of the present invention, it also includes capacitors and resistors required for other circuit components.

[0077] In the embodiment of the present utility model, when the anode and cathode of the optoelectronic isolator U7 are conducted, the emitter and collector are also conducted. At this time, the voltage of V+ of the power isolator U3 is output to the G poles of the MOS transistors Q7 and Q8, and the MOS transistors Q7 and Q8 are conducted, and the positive electrode of the battery BAT is conducted to the second terminal P2. Combining the conduction of the MOS transistors Q5 and Q6 to realize the discharge test of the battery BAT.

[0078] In the embodiment of the present utility model, the first interface and the fourth interface of the control module are connected, and the fourth interface and the fifth interface are connected to perform a discharge test on the test battery. As Figure 1 shown, the fourth interface is D2 and the fifth interface is DA.

[0079] In the embodiment of the present utility model, if the first interface and the fourth interface, and the fourth interface and the fifth interface are connected, then the first interface and the second interface, and the second interface and the third interface will not be connected. Vice versa.

[0080] As Figure 1 shown, as a preferred embodiment of the present utility model, the MOS transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7 and Q8 are N-MOS transistors.

[0081] In the embodiment of the present utility model, N-MOS transistors are used because N-MOS transistors have advantages such as low price and low internal resistance.

[0082] The embodiment of the present utility model also provides a battery polarity switching device in charge and discharge tests, including: the battery polarity switching device in charge and discharge tests includes a test circuit and a battery box;

[0083] The test circuit includes the above-mentioned battery polarity switching circuit in charge and discharge tests;

[0084] The battery box is connected to the test circuit for placing the battery.

[0085] In the embodiment of the present utility model, the battery polarity switching device in charge and discharge tests further includes a sampling module and a display module. The module is used to collect the voltage data and current data of the battery. The display module is used to display the battery performance and electrical parameters of the battery. The electrical parameters include voltage data and current data, and the battery performance includes rated capacity, rated voltage, charge and discharge rate, etc.

[0086] A battery polarity switching device provided by the present utility model for charge and discharge testing forms a first anti-backflow circuit through MOS transistors Q1 and Q2, a second anti-backflow circuit through MOS transistors Q3 and Q4, a third anti-backflow circuit through MOS transistors Q5 and Q6, and a fourth anti-backflow circuit through MOS transistors Q7 and Q8. The battery polarity in the charge and discharge testing is switched by controlling the four anti-backflow circuits. When the first anti-backflow circuit and the second anti-backflow circuit are turned on, MOS transistors Q6 and Q7 are turned off to prevent the current of the battery from entering the third anti-backflow circuit and the fourth anti-backflow circuit; when the third anti-backflow circuit and the fourth anti-backflow circuit are turned on, MOS transistors Q2 and Q3 are turned off to prevent the current of the battery from entering the first anti-backflow circuit and the second anti-backflow circuit. This solves the problem of current backflow of the battery during the charge and discharge testing.

[0087] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A battery polarity switching circuit in a charge and discharge test, characterized in that: The battery polarity switching circuit in the charge and discharge test includes: MOS tube Q1, MOS tube Q2, MOS tube Q3, MOS tube Q4, MOS tube Q5, MOS tube Q6, MOS tube Q7, MOS tube Q8, a first terminal P1, a second terminal P2 and a battery BAT; The D pole of the MOS tube Q1 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS tube Q2, so as to form an anti-backflow circuit with the MOS tube Q2 and switch the polarity of the battery during the charge and discharge test; The D pole of the MOS tube Q2 is connected to the positive pole of the battery BAT; The D pole of the MOS tube Q3 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS tube Q4, so as to form an anti-backflow circuit with the MOS tube Q4 and switch the polarity of the battery during the charge and discharge test; The D pole of the MOS tube Q4 is connected to the second terminal P2; The D pole of the MOS tube Q5 is connected to the first terminal P1, and the S pole is connected to the S pole of the MOS tube Q6, so as to form an anti-backflow circuit with the MOS tube Q6 and switch the polarity of the battery during the charge and discharge test; The D pole of the MOS tube Q6 is connected to the positive pole of the battery BAT; The D pole of the MOS tube Q7 is connected to the negative pole of the battery BAT, and the S pole is connected to the S pole of the MOS tube Q8, so as to form an anti-backflow circuit with the MOS tube Q8 and switch the polarity of the battery during the charge and discharge test; The D pole of the MOS transistor Q8 is connected to the second terminal P2.

2. The battery polarity switching circuit in charge and discharge test according to claim 1, characterized in that: The battery polarity switching circuit in the charge and discharge test also includes a power isolator U1, a photoelectric isolator U5 and a resistor R8; The IN+ interface of the power isolator U1 is connected to the output end of the power module, the IN- interface is connected to the ground line, the V+ interface is connected to the collector of the photoelectric isolator U5 through the resistor R8, and the G interface is connected to the S pole of the MOS tube Q1; The anode of the photoelectric isolator U5 is connected to the first interface of the control module, the cathode is connected to the second interface of the control module, and the emitter is connected to the G electrode of the MOS tube Q1 and the G electrode of the MOS tube Q2.

3. The battery polarity switching circuit in charge and discharge test according to claim 1, characterized in that: The battery polarity switching circuit in the charge and discharge test also includes a power isolator U4, a photoelectric isolator U8 and a resistor R11; The IN+ interface of the power isolator U4 is connected to the output end of the power module, the IN- interface is connected to the ground line, the V+ interface is connected to the collector of the photoelectric isolator U8 through the resistor R11, and the G interface is connected to the S pole of the MOS tube Q3; The anode of the photoelectric isolator U8 is connected to the second interface of the control module, the cathode is connected to the third interface of the control module, and the emitter is connected to the G electrode of the MOS tube Q3 and the G electrode of the MOS tube Q4.

4. The battery polarity switching circuit in charge and discharge test according to claim 1, characterized in that: The battery polarity switching circuit in the charge and discharge test also includes a power isolator U2, a photoelectric isolator U6 and a resistor R9; The IN+ interface of the power isolator U2 is connected to the output end of the power module, the IN- interface is connected to the ground line, the V+ interface is connected to the collector of the photoelectric isolator U6 through the resistor R9, and the G interface is connected to the S pole of the MOS tube Q5; The anode of the photoelectric isolator U6 is connected to the fourth interface of the control module, the cathode is connected to the fifth interface of the control module, and the emitter is connected to the G electrode of the MOS tube Q5 and the G electrode of the MOS tube Q6.

5. The battery polarity switching circuit in charge and discharge test according to claim 1, characterized in that: The battery polarity switching circuit in the charge and discharge test also includes a power isolator U3, a photoelectric isolator U7 and a resistor R10; The IN+ interface of the power isolator U3 is connected to the output end of the power module, the IN- interface is connected to the ground line, the V+ interface is connected to the collector of the photoelectric isolator U7 through the resistor R10, and the G interface is connected to the S pole of the MOS tube Q7; The anode of the photoelectric isolator U7 is connected to the first interface of the control module, the cathode is connected to the fourth interface of the control module, and the emitter is connected to the G electrode of the MOS tube Q7 and the G electrode of the MOS tube Q8.

6. The battery polarity switching circuit in charge and discharge test according to claim 1, characterized in that: The MOS transistor Q1 , MOS transistor Q2 , MOS transistor Q3 , MOS transistor Q4 , MOS transistor Q5 , MOS transistor Q6 , MOS transistor Q7 and MOS transistor Q8 are N-MOS transistors.

7. A battery polarity switching device in charge and discharge testing, characterized in that: The battery polarity switching device in the charge and discharge test includes a test circuit and a battery box; The test circuit comprises a battery polarity switching circuit in a charge and discharge test as described in any one of claims 1 to 6; The battery box is connected to the test circuit and is used for accommodating batteries.

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