CN103269099B - Battery charge-discharge circuit - Google Patents

Abstract

The invention relates to a battery charging and discharging circuit, which includes a power supply, a charging branch used to control the charging operation of the battery and the magnitude of the charging current, and a discharging branch used to control the discharging operation of the battery and the magnitude of the discharging current ; and a protection branch for protecting the battery charging and discharging circuit from performing normal charging and discharging operations. The battery charging and discharging circuit of the present invention avoids the use of energy-consuming components, improves the working efficiency of the entire battery charging and discharging circuit, and is not prone to heat dissipation problems, and can realize multiple charging and discharging circuits connected in parallel to simultaneously charge and discharge large-capacity batteries. Moreover, the short circuit or damage of any single device will not cause the overall failure of the charge and discharge circuit; the entire battery charge and discharge circuit has the characteristics of high efficiency, safety, parallel connection, and good heat dissipation.

Description

Battery charge and discharge circuit

technical field

The invention relates to the field of circuit design, in particular to a high-efficiency, safe, parallel-connectable, and heat-dissipating battery charging and discharging circuit.

Background technique

During the production process of the battery, a series of charging and discharging operations are required. With the development of power vehicles, high-power storage devices and lithium battery technology, the capacity of the battery is getting larger and larger, so the requirements for the battery charging and discharging circuit are also increasing. Higher and higher, safety issues and efficiency issues have become key issues in battery charging and discharging circuits.

Please refer to FIG. 1 , which is a schematic circuit diagram of a conventional battery charging and discharging circuit. Among them, BUS+ and BUS- are the power supply of the battery charge and discharge circuit, SW1 is the charge switch, SW2 is the discharge switch, D1 is the charge anti-reverse charge diode, D2 is the discharge anti-reverse connection short-circuit diode, BAT is the battery, R1 is the sampling resistor . When the battery charging and discharging circuit is charging, the current of the power supply passes through BUS+, charging switch SW1, charging anti-reverse charge diode D1, battery BAT and sampling resistor R1, and finally flows back to the BUS- of the power supply; among them, the charging anti-reverse charge diode D1 It can prevent the reverse charging of the charging circuit when the power supply (BUS+ and BUS-) is not working. When the battery charging and discharging circuit is discharging, the battery BAT forms a discharge circuit through the discharge anti-reverse short-circuit diode D2, the electric switch SW2 and the sampling resistor R1; the discharge anti-reverse short-circuit diode D2 can prevent the abnormal discharge of the battery BAT when it is reversely connected .

However, the charging anti-short circuit diode D1 in the battery charging and discharging circuit is arranged in the charging circuit, which obviously reduces the efficiency of the entire charging circuit, and is prone to generate heat problems. In addition, there is no protection in the circuit for the dangerous consequences that may be caused by the failure of the charging switch SW1, the discharging switch SW2 or other components, resulting in a low safety factor. Therefore, the existing battery charging and discharging circuit has low working efficiency and poor reliability, and poses a certain threat to the safety of the battery and operators during actual use.

Therefore, it is necessary to provide a battery charging and discharging circuit to solve the problems existing in the prior art.

Contents of the invention

The object of the present invention is to provide an efficient, safe, parallel-connectable, and heat-dissipating battery charging and discharging circuit; it prevents the battery from reversely discharging the power supply when the power supply is not working by setting an anti-reverse charging switch tube, and avoids charging and discharging in the charging circuit. The use of energy-consuming components in the battery improves the working efficiency of the entire battery charging and discharging circuit; at the same time, heat dissipation problems are not easy to occur; in the charging switch tube, discharge switch tube, and anti-reverse charge switch tube, any single device short circuit or damage will not cause charging. The direct connection of the discharge circuit, so the reliability of the entire battery charge and discharge circuit is better; to solve the technical problems of low working efficiency and poor reliability of the existing battery charge and discharge circuit.

In order to solve the above problems, the technical solutions provided by the present invention are as follows:

A battery charging and discharging circuit is provided, including:

Power supply;

The charging branch is used to control the charging operation of the battery and the magnitude of the charging current;

a discharge branch circuit, used to control the discharge operation of the battery and the magnitude of the discharge current; and

The protection branch is used to protect the charging and discharging circuit of the battery to perform normal charging and discharging operations;

The input end of the charging branch is connected to the positive pole of the power supply, the output end of the charging branch is respectively connected to the input end of the discharging branch and the input end of the protection branch, and the discharging branch The output end of the circuit is respectively connected with the output end of the protection branch and the negative pole of the power supply.

In the battery charging and discharging circuit according to the present invention, the protection branch includes an anti-reverse charge switch tube, and the anti-reverse charge switch tube is connected in series with the battery in the protection branch circuit, and the anti-reverse charge switch The input end of the tube is connected to the input end of the protection branch, the output end of the anti-reverse charge switch tube is connected to the output end of the protection branch; the positive pole of the battery is connected to the input end of the protection branch connected, the negative pole of the battery is connected to the output terminal of the protection branch.

In the battery charging and discharging circuit according to the present invention, the charging branch circuit includes a charging switch tube, the input end of the charging switch tube is connected to the input terminal of the charging branch circuit, and the output terminal of the charging switch tube is connected to the charging switch tube. The output terminal of the charging branch is connected.

In the battery charging and discharging circuit according to the present invention, the discharge branch circuit includes a discharge switch tube and a discharge anti-reverse short-circuit diode, and the discharge switch tube and the discharge anti-reverse short-circuit diode are connected in series in the discharge branch circuit wherein, the input end of the discharge switch tube is connected to the input end of the discharge branch, the output end of the discharge switch tube is connected to the output end of the discharge branch; the anode of the discharge anti-reverse short-circuit diode It is connected to the input end of the discharge branch, and the cathode of the discharge anti-reverse short-circuit diode is connected to the output end of the discharge branch.

In the battery charging and discharging circuit according to the present invention, the charging branch circuit further includes a charging insurance tube, and the charging insurance tube and the charging switching tube are connected in series in the charging branch circuit.

In the battery charge and discharge circuit of the present invention, the discharge branch circuit further includes a discharge heat dissipation unit, and the discharge heat dissipation unit is connected in series with the discharge switch tube in the discharge branch circuit.

In the battery charging and discharging circuit of the present invention, the discharge heat dissipation unit is at least one discharge heat dissipation diode; the anode of the discharge heat dissipation diode is connected to the input end of the discharge branch, and the cathode of the discharge heat dissipation diode is connected to the discharge branch. The output terminals of the discharge branches are connected.

In the battery charging and discharging circuit of the present invention, the discharge heat dissipation unit is a heat dissipation diode group composed of a plurality of heat dissipation diodes connected in series, and the anode of the first diode of the heat dissipation diode group is connected to the input of the discharge branch circuit. end connection, the cathode of the last diode of the heat dissipation diode group is connected to the output end of the discharge branch

In the battery charging and discharging circuit according to the present invention, the discharge branch circuit further includes a short-circuit switch tube, the short-circuit switch tube is connected in parallel with the discharge heat dissipation unit in the discharge branch circuit, and the short-circuit switch tube is connected to the discharge branch circuit. The discharge switch tube is connected in series in the discharge branch, the input end of the short-circuit switch tube is connected to the input end of the discharge branch circuit, and the output end of the short-circuit switch tube is connected to the output end of the discharge branch circuit .

In the battery charging and discharging circuit of the present invention, the discharge branch circuit further includes a discharge fuse, and the discharge fuse and the discharge switch tube are connected in series in the discharge branch circuit.

In the battery charging and discharging circuit of the present invention, the battery charging and discharging circuit further includes:

The sampling resistor is used to sample the charging current or the discharging current, and the sampling resistor is connected in series with the anti-reverse charging switch tube in the protection branch.

In the battery charging and discharging circuit of the present invention, the positive pole of the battery is connected to the input terminal of the protection branch through the sampling resistor.

In the battery charge and discharge circuit of the present invention, the anti-reverse charge switch tube is at least one field effect transistor with a parasitic diode;

The cathode of the parasitic diode of the anti-reverse switch tube is connected to the output end of the anti-reverse switch tube, and the anode of the parasitic diode of the anti-reverse switch tube is connected to the input end of the anti-reverse switch tube.

In the battery charging and discharging circuit of the present invention, the charging switch tube is at least one field effect transistor with a parasitic diode;

The cathode of the parasitic diode of the charge switch tube is connected to the input end of the charge switch tube, and the anode of the parasitic diode of the charge switch tube is connected to the output end of the charge switch tube.

In the battery charge and discharge circuit of the present invention, the discharge switch tube is at least one field effect transistor with a parasitic diode;

The cathode of the parasitic diode of the discharge switch tube is connected to the input end of the discharge switch tube, and the anode of the parasitic diode of the discharge switch tube is connected to the output end of the discharge switch tube.

In the battery charging and discharging circuit according to the present invention, the protection branch includes an anti-reverse charge switch tube, and the anti-reverse charge switch tube is connected in series with the battery in the protection branch circuit, and the anti-reverse charge switch The input end of the tube is connected to the input end of the protection branch, the output end of the anti-reverse charge switch tube is connected to the output end of the protection branch; the positive pole of the battery is connected to the input end of the protection branch connected, the negative pole of the battery is connected to the output terminal of the protection branch;

The charging branch includes a charging switching tube, the input end of the charging switching tube is connected to the input end of the charging branch circuit, and the output end of the charging switching tube is connected to the output end of the charging branch circuit;

The discharge branch includes a discharge switch tube and a discharge anti-reverse short-circuit diode. The discharge switch tube and the discharge anti-reverse short-circuit diode are connected in series in the discharge branch. The input end of the discharge switch tube is connected to the discharge switch tube. The input end of the discharge branch is connected, the output end of the discharge switch tube is connected with the output end of the discharge branch; the anode of the discharge anti-reverse short circuit diode is connected with the input end of the discharge branch, so The cathode of the discharge anti-reverse short-circuit diode is connected to the output end of the discharge branch;

The charge switch tube, the discharge switch tube and the anti-reverse charge switch tube are all at least one field effect transistor with a parasitic diode;

The cathode of the parasitic diode of the charge switch tube is connected to the input end of the charge switch tube, and the anode of the parasitic diode of the charge switch tube is connected to the output end of the charge switch tube;

The cathode of the parasitic diode of the discharge switch is connected to the input end of the discharge switch, and the anode of the parasitic diode of the discharge switch is connected to the output of the discharge switch;

The cathode of the parasitic diode of the anti-reverse switch tube is connected to the output end of the anti-reverse switch tube, and the anode of the parasitic diode of the anti-reverse switch tube is connected to the input end of the anti-reverse switch tube.

Compared with the existing battery charging and discharging circuit, the battery charging and discharging circuit of the present invention prevents the battery from reversely discharging the power supply when the power supply is not working by setting an anti-reverse charging switch tube, avoiding the use of energy-consuming components in the charging circuit, Improve the working efficiency of the entire battery charge and discharge circuit; at the same time, heat dissipation problems are not easy to occur; in the charge switch tube, discharge switch tube, and anti-reverse charge switch tube, any single device short circuit or damage will not cause the charge and discharge circuit to pass through, so The reliability of the entire battery charging and discharging circuit is good, and the technical problems of low working efficiency and poor reliability of the existing battery charging and discharging circuit are solved.

In order to make the above content of the present invention more obvious and understandable, the preferred embodiments are specifically cited below, and in conjunction with the accompanying drawings, the detailed description is as follows:

Description of drawings

Fig. 1 is the circuit schematic diagram of existing battery charging and discharging circuit;

Fig. 2 is the specific circuit diagram of the first preferred embodiment of the battery charging and discharging circuit of the present invention;

Fig. 3 is the specific circuit diagram of the second preferred embodiment of the battery charging and discharging circuit of the present invention;

Fig. 4 is a specific circuit diagram of the third preferred embodiment of the battery charging and discharging circuit of the present invention.

Detailed ways

The following descriptions of the various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention can be practiced.

In the figures, structurally similar units are denoted by the same reference numerals.

Please refer to FIG. 2 . FIG. 2 is a specific circuit diagram of the first preferred embodiment of the battery charging and discharging circuit of the present invention. The battery charging and discharging circuit in this preferred embodiment includes a power supply, a charging branch 21 , a discharging branch 22 and a protection branch 23 . The charging branch 21 is used to control the charging operation of the battery BAT and the magnitude of the charging current; the discharging branch 22 is used to control the discharging operation of the battery BAT and the magnitude of the discharging current; the protection circuit 23 is used to protect the battery charging and discharging circuit from normal operation. charging and discharging operation.

The input end of the charging branch 21 is connected with the positive pole BUS+ of the power supply, the output end of the charging branch 21 is respectively connected with the input end of the discharging branch 22 and the input end of the protecting branch 23, and the output end of the discharging branch 22 is connected with the input end of the protecting branch 23 respectively. The output end of the protection branch 23 and the negative pole BUS- of the power supply are connected.

The charging branch 21 includes a charging switch tube SW3, the input end of the charging switch tube SW3 is connected to the positive pole BUS+ of the power supply (that is, the input terminal of the charging branch circuit 21), and the output terminal of the charging switch tube SW3 is connected to the protection branch 23 respectively. The input terminal is connected to the input terminal of the discharging branch circuit 22 (ie, the output terminal of the charging branch circuit 21 ).

The discharge branch 22 includes a discharge switch SW4 and a discharge anti-reverse short-circuit diode D3, the discharge switch SW4 and the discharge anti-reverse short-circuit diode D3 are connected in series in the discharge branch 22, and the input ends of the discharge switch SW4 are respectively connected to the charging branch. The output terminal of the circuit 21 and the input terminal of the protection branch circuit 23 (that is, the input terminal of the discharge branch circuit 22) are connected, and the output terminal of the discharge switch tube SW4 is respectively connected with the output terminal of the protection branch circuit 23 and the negative pole BUS- of the power supply (that is, The output end of the discharge branch 22) is connected; the anode of the discharge anti-reverse short-circuit diode D3 is connected to the input end of the discharge branch 22, and the cathode of the discharge anti-reverse short-circuit diode D3 is connected to the output end of the discharge branch 22.

Wherein the protection branch 23 includes an anti-reverse charge switch tube SW5, which is connected in series with the battery BAT in the protection branch circuit, and the input end of the anti-reverse charge switch tube SW5 is respectively connected to the output end of the charge branch circuit 21 and the discharge port. The input end of the branch 22 (that is, the input end of the protection branch 23) is connected, and the output end of the anti-reverse charge switch SW5 is respectively connected to the output end of the discharge branch 22 and the negative pole BUS- of the power supply (that is, the BUS- of the protection branch 23). output terminal), the positive pole of the battery BAT is connected to the input terminal of the protection branch 23, and the negative pole of the battery BAT is connected to the output terminal of the protection branch 23.

The battery charging and discharging circuit in this preferred embodiment further includes a sampling resistor R1 for sampling the charging current or discharging current, and the sampling resistor R1 is connected in series with the anti-reverse charging switch SW5 in the protection branch.

In Fig. 2, the positive pole BUS+ of the power supply, the charge switch SW3, the anti-reverse charge switch SW5, the sampling resistor R1, the battery BAT and the negative pole BUS- of the power supply form a charging circuit. In Fig. 2, the positive electrode of the battery BAT, the sampling resistor R1, the anti-reverse charge switch SW5, the anti-reverse short-circuit diode D3, the discharge switch SW4 and the negative electrode of the battery BAT constitute a discharge circuit.

When the battery charging and discharging circuit of this preferred embodiment is charging, the positive pole BUS+ of the power supply, the charging switch tube SW3, the anti-reverse charging switch tube SW5, the sampling resistor R1, the battery BAT, and the negative pole BUS- of the power supply form a charging circuit. There is no energy consumption element in the battery, and at the same time, the charging switch tube SW3 of the charging branch 21 ensures the control of the power supply access, and the anti-reverse charging switch tube SW5 of the protection branch 23 ensures the protection of the battery BAT, so the entire charging process The charging efficiency is high, and there is no heat dissipation problem, and the reliability of the charging circuit is high.

When the battery charging and discharging circuit in this preferred embodiment is discharging, the positive electrode of the battery BAT, the sampling resistor R1, the anti-reverse charge switch SW5, the anti-reverse short circuit diode D3, the discharge switch SW4 and the negative electrode of the battery BAT form a discharge circuit. In the discharge circuit, the discharge operation is controlled by the discharge switch tube SW4, and at the same time, the short circuit of the discharge circuit caused by the reverse connection of the battery BAT is prevented by the anti-reverse short-circuit diode D3, so the entire discharge process is also efficient and safe. Of course, the anti-reverse short circuit is here Diode D3 can also not be set according to customer requirements.

Please refer to FIG. 3 . FIG. 3 is a specific circuit diagram of a second preferred embodiment of the battery charging and discharging circuit of the present invention. On the basis of the first preferred embodiment, the discharge branch circuit 32 of the battery charging and discharging circuit in this preferred embodiment further includes a discharge heat dissipation unit D4, which is connected in series with the discharge switch tube SW4 in the discharge branch circuit 32 .

In this preferred embodiment, the discharge heat dissipation unit D4 is a discharge heat dissipation diode, the anode of the discharge heat dissipation diode is connected to the input end of the discharge branch 32 , and the cathode of the discharge heat dissipation diode is connected to the output end of the discharge branch 32 .

The discharge branch 32 also includes a short-circuit switch SW6, the short-circuit switch SW6 is connected in parallel with the heat dissipation diode in the discharge branch 32, the short-circuit switch SW6 and the discharge switch SW4 are connected in series in the discharge branch 32, and the short-circuit switch SW6 The input end is connected to the input end of the discharge branch 32 , and the output end of the short-circuit switch SW6 is connected to the output end of the discharge branch 32 . When the battery charging and discharging circuit in this preferred embodiment is performing a discharging operation, the heat dissipation diode can use the discharge energy of the battery BAT to equalize the heat of the discharge switch tube SW4 through its own voltage drop, so that the entire discharge circuit can radiate heat evenly, and prevent a single element from overheating. Reduced service life.

During the discharge process, the voltage of the battery BAT may be lower than the sum of the conduction voltage of the discharge cooling unit D4 and the conduction voltage of the discharge anti-reverse short-circuit diode D3, and the discharge circuit will not be able to perform normal discharge at this time. In this preferred embodiment, the short-circuit switch SW6 short-circuits the discharge heat dissipation unit D4, so that the voltage drop on the discharge circuit is reduced, so that the battery BAT can continue to discharge to achieve a better discharge effect. The short-circuit switch SW6 here can also be a power transistor or a combination of power transistors.

Of course, the discharge heat dissipation unit D4 can also be a heat dissipation diode group composed of a plurality of heat dissipation diodes connected in series. The anode of the diode is connected to the output end of the charge switch SW3 and the input end of the anti-reverse charge switch SW5, and the cathode of the last diode of the heat dissipation diode group is respectively connected to the negative pole BUS- of the power supply and the negative pole of the battery BAT. In this way, the heat dissipation diode group can also play the role of equalizing the heat dissipation of the discharge circuit, and can control the heat dissipation effect to a certain extent by increasing or decreasing the number of heat dissipation diodes.

Please refer to FIG. 4 , which is a specific circuit diagram of a third preferred embodiment of the battery charging and discharging circuit of the present invention. The charging branch 41 of the battery charging and discharging circuit in this preferred embodiment includes a charging switch tube SW3 and a charging fuse F1, and the discharging branch 42 includes a discharging switch tube SW4, a discharge anti-reverse connection short-circuit diode D3, a discharge cooling unit D4, and a short circuit switch. The tube SW6 and the discharge fuse F2, the protection branch includes the anti-reverse charge switch tube SW5 and the sampling resistor R1.

The charge switch tube SW3 is used to control the input power to connect to the battery charge and discharge circuit; the discharge switch tube SW4 is used to control the discharge operation of the battery BAT; the anti-reverse charge switch tube SW5 is used to control the battery BAT to connect to the battery charge and discharge circuit; The reverse connection short-circuit diode D3 is used to prevent the short circuit of the discharge circuit caused by the reverse connection of the battery BAT; the discharge heat dissipation unit D4 is used to balance the heat dissipation of the discharge circuit; the short circuit switch SW6 is used to short-circuit both ends of the discharge heat dissipation unit D4 to improve discharge. Capacity; charging fuse F1 is used to prevent the charging current of the charging circuit from being too large; discharge fuse F2 is used to prevent the discharging current of the discharging circuit from being too large; the sampling resistor R1 is used to detect the charging current of the charging circuit or the discharging current of the discharging circuit.

In this preferred embodiment, specifically, the input end of the charge switch tube SW3 is connected to the positive pole BUS+ of the power supply, the output end of the charge switch tube SW3 is connected to the input end of the anti-reverse charge switch tube SW5, and the anti-reverse charge switch tube SW5 The output end is connected to the positive pole of the battery BAT; the input end of the discharge switch tube SW4 is respectively connected to the output end of the charge switch tube SW3 and the input end of the anti-reverse charge switch tube SW5; the output end of the discharge switch tube SW4 is respectively connected to the negative pole of the power supply BUS- and the negative pole of the battery BAT are connected; the anode of the discharge anti-reverse connection short-circuit diode D3 is respectively connected with the output end of the charge switch tube SW3 and the input end of the anti-reverse charge switch tube SW5; the negative pole of the discharge anti-reverse connection short-circuit diode D3 is respectively connected with The negative pole BUS- of the input power supply is connected to the negative pole of the battery BAT; the discharge switch tube SW4 and the discharge anti-reverse connection short-circuit diode D3 are connected in series in the discharge circuit.

In this preferred embodiment, the charge switch SW3, the discharge switch SW4 and the anti-reverse charge switch SW5 are all power transistors with parasitic diodes (such as insulated gate field effect transistors (MOS) or insulated gate power transistors ( IGBT)) or a combination of power transistors (that is, multiple power transistors connected in series). Wherein the cathode of the parasitic diode of the charge switch tube SW3 is connected with the input end of the charge switch tube SW3, the anode of the parasitic diode of the charge switch tube SW3 is connected with the output end of the charge switch tube SW3; the cathode of the parasitic diode of the discharge switch tube SW4 is connected with the discharge The input end of the switch tube SW4 is connected, the anode of the parasitic diode of the discharge switch tube SW4 is connected with the output end of the discharge switch tube SW4; the cathode of the parasitic diode of the anti-reverse charge switch tube SW5 is connected with the output end of the anti-reverse charge switch tube SW5, The anode of the parasitic diode of the anti-backup switching tube SW5 is connected to the input end of the anti-backup switching tube SW5. In this way, the anode of the parasitic diode of the charge switch tube SW3 is connected to the anode of the parasitic diode of the anti-reverse charge switch tube SW5, which prevents the battery from abnormally charging through the parasitic diode of the charge switch tube SW3 and the parasitic diode of the anti-reverse charge switch tube SW5. Charge and discharge; at the same time, the cathode of the parasitic diode of the discharge switch SW4 is connected to the anode of the discharge anti-reverse short-circuit diode D3, which avoids abnormal charging and discharging of the battery through the parasitic diode of the discharge switch SW4 and the discharge anti-reverse short-circuit diode D3 .

In this preferred embodiment, the discharge cooling unit D4 and the short circuit switch SW6 are connected in parallel in the discharge circuit. The discharge heat dissipation unit can be a heat dissipation diode, the anode of the heat dissipation diode is respectively connected to the input end of the charging switch SW3 and the input end of the anti-reverse charge switch SW5, and the cathode of the heat dissipation diode is respectively connected to the negative pole BUS- of the power supply and the battery BAT The negative connection of the heat dissipation diode, that is, the heat dissipation diode is connected in series in the discharge circuit. When the battery charge and discharge circuit in this preferred embodiment is performing discharge operation, the heat dissipation diode can consume the discharge energy of the battery BAT through its own voltage drop, so as to balance the heat dissipation of the entire discharge circuit and avoid local overheating of the discharge circuit.

The battery charging and discharging circuit in this preferred embodiment also includes a charging fuse F1 and a discharging fuse F2. The charging fuse F1 is connected in series in the charging branch, and is used to automatically disconnect the charging branch when the charging current in the charging branch is too large. circuit to protect the components in the charging branch. The discharge fuse F2 is connected in series in the discharge branch, and is used to automatically disconnect the discharge circuit to protect the components in the discharge branch when the discharge current in the discharge branch is too large.

The battery charging and discharging circuit in this preferred embodiment further includes a sampling resistor R1, which is connected in series in the protection branch at the same time, and is used to detect the charging current of the charging circuit and the discharging current of the discharging circuit. Specifically, the positive pole of the battery is connected to the input terminal of the protection branch through the sampling resistor. Since the sampling resistor is set at the positive terminal of the battery, multiple battery charging and discharging circuits can be connected in parallel to charge a battery, and at the same time, the charging current of each charging circuit can be accurately detected (such as setting the sampling resistor at the negative terminal of the battery, If multiple battery charging and discharging circuits are connected in parallel, since the protection circuits of multiple battery charging and discharging circuits share the negative BUS- of a power supply, the detected charging current of each charging circuit may be inaccurate.

When the battery charging and discharging circuit of this preferred embodiment is charging, the positive pole BUS+ of the power supply, the charging switch tube SW3, the charging insurance tube F1, the anti-reverse charging switch tube SW5, the sampling resistor R1, the battery BAT and the negative pole BUS- of the power supply form a charging There is no energy consumption element in the charging circuit, and at the same time, the control of the input power supply is guaranteed through the charging switch tube SW3, and the control of the battery BAT access is guaranteed through the anti-reverse charging switch tube SW5, and the sampling resistor R1 can be used to control the The charging current is detected, and the excessive charging current is controlled through the charging fuse F1. Therefore, the charging efficiency of the whole charging process is high, and there is no heat dissipation problem, and the reliability of the charging circuit is high.

When the battery charging and discharging circuit of this preferred embodiment is discharging, when the discharge starts, the short-circuit switch SW6 is disconnected, the positive pole of the battery BAT, the sampling resistor R1, the anti-reverse charge switch SW5, the discharge fuse F2, and the discharge anti-reverse short-circuit diode D3 , the discharge cooling unit D4, the discharge switch tube SW4 and the negative electrode of the battery BAT form a discharge circuit. At this time, the discharge anti-reverse connection short-circuit diode D3 and the discharge cooling unit D4 can evenly disperse the heat of the discharge circuit, ensuring the safety and reliability of the discharge circuit. At the same time, the discharge current can be detected through the sampling resistor R1, and the excessive discharge current can be controlled through the discharge fuse F2. At the later stage of discharge, the short-circuit switch SW6 is closed, and the discharge cooling unit D4 is short-circuited. At this time, the positive pole of the battery BAT, the sampling resistor R1, the anti-reverse charge switch SW5, the discharge fuse F2, the discharge anti-reverse connection short-circuit diode D3, and the short circuit The switch tube SW6, the discharge switch tube SW4 and the negative electrode of the battery BAT form a discharge circuit, which reduces the load on the discharge circuit, so that the discharge circuit can discharge the battery BAT more fully.

Therefore, the battery charging and discharging circuit of this preferred embodiment avoids the use of energy-consuming elements in the charging circuit, improves the working efficiency of the entire battery charging and discharging circuit, can be used in parallel to charge and discharge large-capacity batteries, and is not prone to heat dissipation problems, so The safety and reliability of the charging circuit of the entire battery charging and discharging circuit are better. At the same time, the setting of the short-circuit switch tube and the discharge cooling unit in the discharge circuit not only ensures the full discharge of the battery, but also ensures the stability of the heat dissipation of the discharge circuit, and strengthens the safety and reliability of the discharge circuit of the battery charge and discharge circuit.

In summary, although the present invention has been disclosed above with preferred embodiments, the above preferred embodiments are not intended to limit the present invention, and those of ordinary skill in the art can make various modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims (12)

1. A battery charging and discharging circuit, characterized in that, comprising: Power supply; The charging branch is used to control the charging operation of the battery and the magnitude of the charging current; a discharge branch circuit, used to control the discharge operation of the battery and the magnitude of the discharge current; and The protection branch is used to protect the charging and discharging circuit of the battery to perform normal charging and discharging operations; The input end of the charging branch is connected to the positive pole of the power supply, the output end of the charging branch is respectively connected to the input end of the discharging branch and the input end of the protection branch, and the discharging branch The output end of the circuit is respectively connected with the output end of the protection branch circuit and the negative pole of the power supply; The discharge branch includes a discharge switch tube and a discharge anti-reverse short-circuit diode. The discharge switch tube and the discharge anti-reverse short-circuit diode are connected in series in the discharge branch. The input end of the discharge switch tube is connected to the discharge switch tube. The input end of the discharge branch is connected, the output end of the discharge switch tube is connected with the output end of the discharge branch; the anode of the discharge anti-reverse short circuit diode is connected with the input end of the discharge branch, so The cathode of the discharge anti-reverse short-circuit diode is connected to the output end of the discharge branch; The discharge branch circuit also includes a discharge heat dissipation unit, and the discharge heat dissipation unit is connected in series with the discharge switch tube in the discharge branch circuit; The discharge heat dissipation unit is at least one discharge heat dissipation diode; the anode of the discharge heat dissipation diode is connected to the input end of the discharge branch, and the cathode of the discharge heat dissipation diode is connected to the output end of the discharge branch; The discharge branch also includes a short-circuit switch tube, the short-circuit switch tube is connected in parallel with the discharge cooling unit in the discharge branch circuit, and the short-circuit switch tube and the discharge switch tube are connected in series in the discharge branch circuit , the input end of the short-circuit switch tube is connected to the input end of the discharge branch, and the output end of the short-circuit switch tube is connected to the output end of the discharge branch circuit. 2. The battery charging and discharging circuit according to claim 1, wherein the protection branch circuit includes an anti-reverse charging switch tube, and the anti-reverse charge switch tube is connected in series with the battery in the protection branch circuit, The input end of the anti-reverse charge switch tube is connected to the input end of the protection branch, the output end of the anti-reverse charge switch tube is connected to the output end of the protection branch circuit; the positive pole of the battery is connected to the The input end of the protection branch is connected, and the negative pole of the battery is connected with the output end of the protection branch. 3. The battery charging and discharging circuit according to claim 1, wherein the charging branch includes a charging switching tube, the input end of the charging switching tube is connected to the input end of the charging branch, and the charging The output end of the switch tube is connected with the output end of the charging branch. 4. The battery charging and discharging circuit according to claim 3, characterized in that, The charging branch also includes a charging fuse, which is connected in series with the charging switching tube in the charging branch. 5. The battery charging and discharging circuit according to claim 1, characterized in that, The discharge heat dissipation unit is a heat dissipation diode group composed of a plurality of heat dissipation diodes connected in series, the anode of the first diode of the heat dissipation diode group is connected to the input end of the discharge branch, and the last diode of the heat dissipation diode group The cathode of is connected to the output terminal of the discharge branch. 6. The battery charging and discharging circuit according to claim 1, characterized in that, The discharge branch circuit further includes a discharge fuse, and the discharge fuse is connected in series with the discharge switch tube in the discharge branch circuit. 7. The battery charging and discharging circuit according to claim 2, characterized in that, The battery charging and discharging circuit also includes: The sampling resistor is used to sample the charging current or the discharging current, and the sampling resistor is connected in series with the anti-reverse charging switch tube in the protection branch. 8 . The battery charging and discharging circuit according to claim 7 , wherein the positive pole of the battery is connected to the input terminal of the protection branch through the sampling resistor. 9. The battery charge and discharge circuit according to claim 2, wherein the anti-reverse charge switch tube is at least one field effect transistor with a parasitic diode; The cathode of the parasitic diode of the anti-reverse switch tube is connected to the output end of the anti-reverse switch tube, and the anode of the parasitic diode of the anti-reverse switch tube is connected to the input end of the anti-reverse switch tube. 10. The battery charging and discharging circuit according to claim 3, wherein the charging switch tube is at least one field effect transistor with a parasitic diode; The cathode of the parasitic diode of the charge switch tube is connected to the input end of the charge switch tube, and the anode of the parasitic diode of the charge switch tube is connected to the output end of the charge switch tube. 11. The battery charge and discharge circuit according to claim 1, wherein the discharge switch tube is at least one field effect transistor with a parasitic diode; The cathode of the parasitic diode of the discharge switch tube is connected to the input end of the discharge switch tube, and the anode of the parasitic diode of the discharge switch tube is connected to the output end of the discharge switch tube. 12. The battery charging and discharging circuit according to claim 1, characterized in that it comprises: The protection branch includes an anti-reverse charge switch tube, the anti-reverse charge switch tube is connected in series with the battery in the protection branch circuit, the input end of the anti-reverse charge switch tube is connected to the input of the protection branch circuit The output end of the anti-reverse charge switch tube is connected to the output end of the protection branch; the positive pole of the battery is connected to the input end of the protection branch, and the negative pole of the battery is connected to the protection branch The output terminal of the road is connected; The charging branch includes a charging switching tube, the input end of the charging switching tube is connected to the input end of the charging branch circuit, and the output end of the charging switching tube is connected to the output end of the charging branch circuit; The discharge branch includes a discharge switch tube and a discharge anti-reverse short-circuit diode. The discharge switch tube and the discharge anti-reverse short-circuit diode are connected in series in the discharge branch. The input end of the discharge switch tube is connected to the discharge switch tube. The input end of the discharge branch is connected, the output end of the discharge switch tube is connected with the output end of the discharge branch; the anode of the discharge anti-reverse short circuit diode is connected with the input end of the discharge branch, so The cathode of the discharge anti-reverse short-circuit diode is connected to the output end of the discharge branch; The charge switch tube, the discharge switch tube and the anti-reverse charge switch tube are all at least one field effect transistor with a parasitic diode; The cathode of the parasitic diode of the charge switch tube is connected to the input end of the charge switch tube, and the anode of the parasitic diode of the charge switch tube is connected to the output end of the charge switch tube; The cathode of the parasitic diode of the discharge switch is connected to the input end of the discharge switch, and the anode of the parasitic diode of the discharge switch is connected to the output of the discharge switch; The cathode of the parasitic diode of the anti-reverse switch tube is connected to the output end of the anti-reverse switch tube, and the anode of the parasitic diode of the anti-reverse switch tube is connected to the input end of the anti-reverse switch tube.