WO2018099357A1

WO2018099357A1 - Overcharge protection circuit and overdischarge protection circuit for power battery

Info

Publication number: WO2018099357A1
Application number: PCT/CN2017/113294
Authority: WO
Inventors: 谢哲锋; 陈武; 蒋步洪
Original assignee: 比亚迪股份有限公司
Priority date: 2016-11-30
Filing date: 2017-11-28
Publication date: 2018-06-07
Also published as: CN206432703U

Abstract

An overcharge protection circuit and an overdischarge protection circuit for a power battery. The overcharge protection circuit comprises: a first voltage measurement circuit (10), the first voltage measurement circuit being connected to a power battery and used for measuring a voltage of the power battery and outputting an overcharge protection signal when the voltage of the power battery is greater than a first reference voltage; a first latching circuit (20), the first latching circuit being connected to the first voltage measurement circuit and a charge control loop (200) respectively and used for controlling the charge control loop to be in a disconnected state after receiving the overcharge protection signal, thereby effectively preventing the power battery from being overcharged and avoiding, in the case that the power battery is fully charged and there is no current, the risk of overcharge reoccurrence after the voltage of the power battery decreases to the first reference voltage.

Description

Overcharge protection circuit and over discharge protection circuit of power battery

Cross-reference to related applications

The present application is based on a Chinese patent application filed on Nov. 30, 2016, the entire disclosure of which is hereby incorporated by reference.

Technical field

The invention relates to the technical field of charging and discharging, in particular to an overcharge protection circuit for a power battery, an over discharge protection circuit for a power battery, a charge and discharge protection device for a power battery, a battery management system and an electric vehicle. .

Background technique

At present, the overcharge protection of the power battery is mainly integrated in the battery management system. The system collects the voltage of the power battery in real time and judges the collected voltage. When the voltage reaches the overcharge protection voltage point, the system issues an instruction to control the corresponding protection. The relay operates to realize overcharge protection of the power battery by software.

In the related art, the overcharge protection of the power battery is also realized by hardware. As shown in FIG. 1, the battery voltage is sampled by a circuit composed of a resistor and a voltage stabilizing device, and then compared with a reference voltage when the battery voltage is greater than the reference voltage. The high level signal is outputted to the subsequent circuit to control the action of the corresponding protection relay, thereby achieving overcharge protection of the power battery.

However, whether it is software or hardware, when the power battery stops charging (discharging), its voltage will drop (rise), and the system will charge (discharge) the power battery again, causing the power battery to repeat. Charging (over-discharge), to a certain extent, reduces the life of the power battery.

Summary of the invention

The present invention aims to solve at least one of the technical problems in the related art to some extent.

Therefore, the first object of the present invention is to provide an overcharge protection circuit for a power battery, which is controlled by the self-locking function of the circuit to keep the charging control circuit in an off state, thereby effectively avoiding overcharging of the power battery while avoiding After the power battery reaches full charge, in the absence of current, the voltage of the power battery automatically falls to the first reference voltage, and the risk of overcharging occurs again, effectively improving the service life of the power battery.

A second object of the present invention is to provide an over discharge protection circuit for a power battery.

A third object of the present invention is to provide a charge and discharge protection device for a power battery.

A fourth object of the present invention is to provide a battery management system.

A fifth object of the present invention is to provide an electric vehicle.

In order to achieve the above object, an overcharge protection circuit for a power battery according to a first aspect of the present invention includes: a first voltage detection circuit, wherein the first voltage detection circuit is connected to a power battery, and the first voltage detection circuit is used. In order to detect the voltage of the power battery, and output an overcharge protection signal when the voltage of the power battery is greater than the first reference voltage; the first self-locking circuit, the first self-locking circuit and the first voltage detection respectively The circuit is connected to the charging control circuit, and the first self-locking circuit is configured to control the charging control loop to be in an off state after receiving the overcharge protection signal.

According to the overcharge protection circuit of the power battery of the present invention, the voltage of the power battery is detected by the first voltage detecting circuit, and the overcharge protection signal is output to the first self-locking circuit when the voltage of the power battery is greater than the first reference voltage, first The self-locking circuit controls the charging control circuit to be in an off state after receiving the overcharge protection signal, thereby effectively avoiding overcharging of the power battery, and avoiding the voltage of the power battery in the absence of current after the power battery reaches full charge. After automatically falling to the first reference voltage, the risk of overcharging occurs again, effectively improving the service life of the power battery.

Specifically, the first self-locking circuit includes: a first resistor, one end of the first resistor is connected to the first voltage detecting circuit; a first MOS transistor, a gate of the first MOS transistor, and the The other end of the first resistor is connected, the source of the first MOS transistor is connected to the second ground, and the drain of the first MOS transistor is connected to one end of the first resistor; the first relay, the first One end of a coil of a relay is respectively connected to a drain of the first MOS transistor, one end of the first resistor, and one end of a normally open contact of the first relay, and the other end of the coil of the first relay Connected to the second preset power source and the other end of the normally open contact of the first relay, respectively, the two ends of the normally closed contact of the first relay are connected in the charging control loop.

Specifically, the first self-locking circuit includes: a second MOS transistor, a third MOS transistor, a fourth MOS transistor, a second resistor, a third resistor, a first capacitor, and a second relay; wherein the second MOS a gate of the tube is connected to the first voltage detecting circuit, a source of the second MOS transistor is grounded; a gate of the third MOS transistor is connected to a drain of the second MOS transistor, the third The gate of the MOS transistor is also connected to the preset power source through a second resistor, the source of the third MOS transistor is connected to the ground; the gate of the fourth MOS transistor is connected to the drain of the third MOS transistor The gate of the fourth MOS transistor is further connected to the preset power source through a third resistor, the source of the fourth MOS transistor is connected to the ground, and the source of the fourth MOS transistor is also passed through the first a capacitor is connected to the gate of the fourth MOS transistor; one end of the coil of the second relay is connected to the drain of the fourth MOS transistor, and the other end of the coil of the second relay is opposite to the preset The power source is connected, one end of the normally open contact of the second relay is connected to the gate of the third MOS tube, and the normally open contact of the second relay is another The end, the normally closed contact ends of the second relay is connected to the charge control circuit.

Specifically, the first voltage detecting circuit includes: a first comparator, a fourth resistor, a fifth resistor, a first temperature compensation circuit, and a first photocouple; wherein a positive input end of the first comparator The positive pole of the power battery is connected, the output end of the first comparator is connected to the first preset power source through a fourth resistor; one end of the fifth resistor is connected to the first preset power source, the fifth resistor The other end is connected to the negative input end of the first comparator; one end of the first temperature compensation circuit is respectively connected to the negative input end of the first comparator and the other end of the fifth resistor, First temperature supplement The other end of the compensation circuit is connected to the negative pole of the power battery, the voltage of one end of the first temperature compensation circuit is the first reference voltage; and the first input end of the first optocoupler is compared with the first The output end of the first photocoupler is connected to the first ground end, and the first output end of the first optocoupler is connected to the second preset power source, the first optocoupler The second output is coupled to the first latching circuit.

Specifically, the first temperature compensation circuit includes a first PTC module.

Further, the above-mentioned overcharge protection circuit of the power battery further includes a first DC/DC isolated power supply module, and the first DC/DC isolated power supply module is configured to convert the second preset power supply into the first The power source is preset, and the first preset power source and the second preset power source are isolated.

Specifically, the first voltage detecting circuit includes: a Zener diode, a third optocoupler, a fifteenth resistor, a sixteenth resistor, and a first temperature compensation circuit; wherein the cathode of the Zener tube and the first temperature compensation circuit Connected; the first input end of the third optocoupler is connected to the anode of the Zener diode, and the second input end of the third optocoupler is connected to the negative pole of the power battery; the first output of the fifteenth resistor and the first output of the third optocoupler The other end of the fifteenth resistor is connected to the first temperature compensating circuit; one end of the sixteenth resistor is respectively connected to the second output end of the third optocoupler and the first self-locking circuit, and the other end of the sixteenth resistor Ground.

Specifically, the first temperature compensation circuit includes a third PTC module and a fourth PTC module; wherein one end of the third PTC module is connected to the cathode of the Zener tube, and the other end of the third PTC module is connected to the anode of the power battery. One end of the fourth PTC module is connected to the other end of the fifteenth resistor, and the other end of the fourth PTC module is connected to the preset power source.

In order to achieve the above object, an over-discharge protection circuit for a power battery according to a second aspect of the present invention includes: a second voltage detecting circuit, wherein the second voltage detecting circuit is connected to a power battery, and the second voltage detecting circuit is used In order to detect the voltage of the power battery, and output an over-discharge protection signal when the voltage of the power battery is less than the second reference voltage; the second self-locking circuit, the second self-locking circuit and the second voltage detection respectively The circuit is connected to the discharge control circuit, and the second self-locking circuit is configured to control the discharge control loop to be in an off state after receiving the overdischarge protection signal.

According to the over-discharge protection circuit of the power battery of the present invention, the voltage of the power battery is detected by the second voltage detecting circuit, and the over-discharge protection signal is outputted to the second self-locking circuit when the voltage of the power battery is less than the second reference voltage, and the second The self-locking circuit controls the discharge control circuit to be in the off state after receiving the over-discharge protection signal, thereby effectively preventing the power battery from being over-discharged, and avoiding the power battery without discharging, the voltage of the power battery is automatically increased by several tens mV, causing the discharge control circuit to close again, the risk of over-discharge of the power battery again, improving the service life of the power battery.

Specifically, the second self-locking circuit includes: a sixth resistor, one end of the sixth resistor is connected to the second voltage detecting circuit; a fifth MOS transistor, a gate of the fifth MOS transistor, and the The other end of the sixth resistor is connected, the source of the fifth MOS transistor is connected to the second ground, the drain of the fifth MOS transistor is connected to one end of the sixth resistor; and the third relay One end of the coil of the three relay is respectively connected to the drain of the fifth MOS tube, one end of the sixth resistor, and one end of the normally open contact of the third relay, and the other end of the coil of the third relay Connected to the second preset power source and the other end of the normally open contact of the third relay, respectively, the two ends of the normally closed contact of the third relay are connected at In the discharge control loop.

Specifically, the second self-locking circuit includes: a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a seventh resistor, an eighth resistor, a second capacitor, and a fourth relay; wherein the sixth MOS a gate of the tube is connected to the second voltage detecting circuit, a source of the sixth MOS transistor is grounded; a gate of the seventh MOS transistor is connected to a drain of the sixth MOS transistor, the seventh The gate of the MOS transistor is further connected to the preset power source through a seventh resistor, the source of the seventh MOS transistor is connected to the ground; the gate of the eighth MOS transistor is connected to the drain of the seventh MOS transistor The gate of the eighth MOS transistor is further connected to the preset power source through an eighth resistor, the source of the eighth MOS transistor is connected to the ground, and the source of the eighth MOS transistor is further passed through the second a capacitor is connected to a gate of the eighth MOS transistor; one end of the coil of the fourth relay is connected to a drain of the eighth MOS transistor, and the other end of the coil of the fourth relay is connected to the preset power source Connected, one end of the normally open contact of the fourth relay is connected to the gate of the seventh MOS tube, and the other of the normally open contacts of the fourth relay Connected to the ends of the normally closed contact of the fourth relay is connected to said discharge control circuit.

Specifically, the second voltage detecting circuit includes: a second comparator, a ninth resistor, a tenth resistor, a second temperature compensation circuit, and a second optocoupler; wherein a negative input end of the second comparator The positive pole of the power battery is connected, the output end of the second comparator is connected to the first preset power source through a ninth resistor; one end of the tenth resistor is connected to the first preset power source, and the tenth resistor The other end is connected to the positive input end of the second comparator; one end of the second temperature compensation circuit is respectively connected to the positive input end of the second comparator and the other end of the tenth resistor, The other end of the second temperature compensation circuit is connected to the negative pole of the power battery, the voltage of one end of the second temperature compensation circuit is the second reference voltage; the first input end of the second optocoupler is The output end of the second comparator is connected, the second input end of the second optocoupler is connected to the first ground end, and the first output end of the second optocoupler is connected to the second preset power source, the second a second output of the optocoupler and the second self-locking Connected to the road.

Specifically, the second temperature compensation circuit includes a second PTC module.

Further, the above-mentioned over-current protection circuit of the power battery further includes a second DC/DC isolated power supply module, and the second DC/DC isolated power supply module is configured to convert the second preset power supply into the first The power source is preset, and the first preset power source and the second preset power source are isolated.

In order to achieve the above object, a third aspect of the present invention provides a charge and discharge protection device for a power battery, comprising the above-described overcharge protection circuit and over discharge protection circuit of the power battery.

The charge and discharge protection device for the power battery of the present invention can effectively prevent the power battery from being overcharged by the overcharge protection circuit and the over discharge protection circuit of the power battery described above, and avoid the situation that the power battery has no current after reaching full charge. Under the condition that the voltage of the power battery automatically falls to the first reference voltage, the risk of overcharging occurs again, and the power battery can be effectively prevented from being over-discharged, and the voltage of the power battery is automatically increased when the power battery is not discharged. A few tens of mV, causing the normally open contact of the relay to open, the normally closed contact to close, and the risk of overdischarge occurring again.

In order to achieve the above object, a fourth aspect of the present invention provides a battery management system including the above power battery Charge and discharge protection device.

The battery management system of the present invention can effectively prevent the power battery from being overcharged by the above-mentioned charge and discharge protection device of the power battery, and avoid the power battery voltage automatically falling after the power battery reaches full charge. After the first reference voltage, the risk of overcharging occurs again, and the power battery can be effectively prevented from being over-discharged, and the voltage of the power battery is automatically increased by several tens of mV when the power battery is not discharged, resulting in a normally open relay. The contact is open and the normally closed contact is closed, and the risk of overdischarge occurs again.

In order to achieve the above object, a fifth aspect of the present invention provides an electric vehicle including the above-described charge and discharge protection device for a power battery.

The automobile of the present invention can effectively prevent the power battery from being overcharged by the above-mentioned charging and discharging protection device of the power battery, and avoid the power battery voltage automatically falling to the first state without the current after the power battery reaches full charge. After the reference voltage, the risk of overcharging occurs again, and the power battery can be effectively prevented from being over-discharged, and the voltage of the power battery is automatically increased by several tens of mV, resulting in the normally open contact of the relay. Disconnected, the normally closed contact closes, and the risk of overdischarge occurs again.

DRAWINGS

1 is a charge and discharge protection circuit of a power battery in the related art.

2 is a block diagram of an overcharge protection circuit of a power battery according to an embodiment of the present invention;

3 is a circuit diagram of a first self-locking circuit in an overcharge protection circuit of a power battery according to an embodiment of the present invention;

4 is a circuit diagram of a first self-locking circuit in an overcharge protection circuit of a power battery according to another embodiment of the present invention;

5 is a circuit diagram of an overcharge protection circuit of a power battery according to an embodiment of the present invention;

6 is a circuit diagram of an overcharge protection circuit of a power battery according to another embodiment of the present invention;

7 is a block diagram of an over-discharge protection circuit of a power battery according to an embodiment of the present invention;

8 is a circuit diagram of a second self-locking circuit in an over-discharge protection circuit of a power battery according to an embodiment of the present invention;

9 is a circuit diagram of a second self-locking circuit in an over-discharge protection circuit of a power battery according to another embodiment of the present invention;

10 is a circuit diagram of an over-discharge protection circuit of a power battery according to an embodiment of the present invention;

11 is a circuit diagram of a charge and discharge protection device for a power battery according to an embodiment of the present invention;

12 is a schematic structural view of a charge and discharge protection device for a power battery according to an embodiment of the present invention;

Figure 13 is a schematic illustration of a battery management system in accordance with one embodiment of the present invention.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The following is described by referring to the figures. The examples are intended to be illustrative of the invention and are not to be construed as limiting.

An overcharge protection circuit for a power battery, an over discharge protection circuit for a power battery, a charge and discharge protection device for a power battery, a battery management system, and an automobile according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

2 is a block diagram of an overcharge protection circuit for a power battery in accordance with one embodiment of the present invention. As shown in FIG. 2, the overcharge protection circuit of the power battery may include a first voltage detecting circuit 10 and a first self-locking circuit 20.

The first voltage detecting circuit 10 is connected to the power battery Battery. The first voltage detecting circuit 10 is configured to detect the voltage of the power battery Battery, and output an overcharge protection signal when the voltage of the power battery Battery is greater than the first reference voltage. The first self-locking circuit 20 is respectively connected to the first voltage detecting circuit 10 and the charging control circuit 200. The first self-locking circuit 20 is configured to control the charging control circuit 200 to be in an off state after receiving the overcharge protection signal.

Specifically, in the process of charging the battery of the power battery, in order to prevent overcharging of the battery of the power battery, the voltage of the battery of the power battery can be detected in real time by the first voltage detecting circuit 10, when the voltage of the battery of the power battery reaches the first reference voltage. The power battery is fully charged. At this time, the charging control circuit 200 is controlled to be disconnected by the first self-locking circuit 20 to prevent the battery of the power battery from being continuously charged, resulting in overcharging of the power battery. At the same time, the charging control circuit 200 is always in the off state by the self-locking function of the first self-locking circuit 20, effectively preventing the power battery from automatically dropping to the first state when there is no current after the power battery reaches full charge. After the reference voltage, the risk of overcharging occurs again, effectively improving the service life of the power battery.

It should be noted that, since the power battery is formed by connecting a plurality of single cells or battery packs in series, a plurality of first voltage detecting circuits 10 may be disposed. For example, one battery or battery pack may be connected to each battery. The first voltage detecting circuit 10 and the output ends of the plurality of first voltage detecting circuits 10 are connected to the first self-locking circuit 20 by being connected to the logic circuit, so that over-cell protection can be realized for each battery or battery pack.

According to an embodiment of the present invention, as shown in FIG. 3, the first self-locking circuit 20 may include a first resistor R1, a first MOS transistor Q1, and a first relay K1. One end of the first resistor R1 is connected to the first voltage detecting circuit 10, the gate of the first MOS transistor Q1 is connected to the other end of the first resistor R1, and the source of the first MOS transistor Q1 is connected to the second ground GND2. The drain of the first MOS transistor Q1 is connected to one end of the first resistor R1. One end of the coil K1M of the first relay K1 is respectively connected to the drain of the first MOS transistor Q1, one end of the first resistor R1, and one end of the normally open contact K11 of the first relay K1, and the other coil K1M of the first relay K1 One end is connected to the second preset power source VCC2 and the other end of the normally open contact K11 of the first relay K1, respectively, and both ends of the normally closed contact K12 of the first relay K1 are connected in the charge control circuit 200.

Specifically, as shown in FIG. 3, when the power battery Battery is overcharged, the first voltage detecting circuit 10 outputs an overcharge protection signal (such as a high level signal) to the first self-locking circuit 20, and the first MOS The tube Q1 is in an on state, a current flows through the coil K1M of the first relay K1, the normally closed contact K12 of the first relay K1 is turned off, the charging control circuit 200 is disconnected, and the battery of the power battery is stopped, thereby realizing the power battery. Overcharge protection, at the same time, the normally open contact K11 of the first relay K1 is also closed, because one end of the normally open contact K11 of the first relay K1 and the first resistor R1 One end is connected, and the other end is connected to the second preset power source VCC2. Therefore, after the normally open contact K11 is closed, the current of the second preset power source VCC2 flows to the one end of the first resistor R1 through the normally open contact K11, so that even The first voltage detecting circuit 20 outputs a low-level signal, and the first MOS transistor Q1 is still in an on state, thereby realizing the self-locking function of the circuit, effectively preventing the power battery from reaching full charge, and in the absence of current, the power battery After the voltage automatically drops to the first reference voltage, the normally open contact of the relay is opened, the normally closed contact is closed, and the risk of overcharging occurs again.

In practical applications, the first relay K1 can also be replaced by other methods. For example, a normally open relay and a normally closed relay can be used in series, or a single pole double throw relay can be used, which can be selected according to actual conditions. From the perspective of safety and the area of the PCB board occupied, it is preferable to use a relay having a set of independent normally open contacts and a set of normally closed contacts as shown in FIG.

Further, as shown in FIG. 3, the above-mentioned overcharge protection circuit of the power battery may further include a first filter circuit 30, and the first filter circuit 30 may include an eleventh resistor R11 and a third capacitor C3, wherein the eleventh One end of the resistor R11 is connected to the gate of the first MOS transistor Q1, the other end of the eleventh resistor R11 is connected to the second ground GND2, and the third capacitor C3 is connected in parallel with the eleventh resistor R11. The eleventh resistor R11 and the third capacitor C3 form an RC filter circuit to eliminate external interference and ensure control stability.

According to another embodiment of the invention, as shown in FIG. 4, the first self-locking circuit 20 may include a second MOS transistor Q2, a third MOS transistor Q3, a fourth MOS transistor Q4, a second resistor R2, and a third resistor R3. The first capacitor C1 and the second relay K2. The gate of the second MOS transistor Q2 is connected to the first voltage detecting circuit 10, and the source of the second MOS transistor Q2 is connected to the ground GND. The gate of the third MOS transistor Q3 is connected to the drain of the second MOS transistor Q2, the gate of the third MOS transistor Q3 is also connected to the preset power supply VCC through the second resistor R2, and the source of the third MOS transistor Q3 is grounded to GND. . The gate of the fourth MOS transistor Q4 is connected to the drain of the third MOS transistor Q3, the gate of the fourth MOS transistor Q4 is also connected to the preset power supply VCC through the third resistor R3, and the source of the fourth MOS transistor Q4 is grounded to GND. The source of the fourth MOS transistor Q4 is also connected to the gate of the fourth MOS transistor Q4 through the first capacitor C1. One end of the coil K2M of the second relay K2 is connected to the drain of the fourth MOS transistor Q4, the other end of the coil K2M of the second relay K2 is connected to the preset power source VCC, and one end of the normally open contact K21 of the second relay K2 is The gate of the third MOS transistor Q3 is connected, the other end of the normally open contact K21 of the second relay K2 is grounded to GND, and both ends of the normally closed contact K22 of the second relay K2 are connected to the charge control circuit 200.

Specifically, when the power battery Battery is overcharged, the first voltage detecting circuit 10 outputs an overcharge protection signal (such as a high level signal) to the first self-locking circuit 20, and at this time, the second MOS transistor Q2 is turned on, The three MOS transistors Q3 are turned off, the fourth MOS transistor Q4 is turned on, the coil K2M of the second relay K2 is energized, the normally closed contact K22 of the second relay K2 is turned off, and the charging control circuit 200 is turned off, thereby preventing power. The battery is overcharged. At the same time, the normally open contact K21 of the second relay K2 is closed. Since the normally open contact K21 is closed, the gate voltage of the third MOS transistor Q3 is always zero, and the third MOS transistor Q3 is always turned off. The state, so that the fourth MOS transistor Q4 is always in the on state, the coil K2M of the second relay K2 is always in the power-on state, thereby realizing the self-locking function of the circuit, effectively preventing the power battery from reaching full charge, In the case of current, the voltage of the power battery is automatically reduced to the corresponding voltage threshold, the normally open contact of the relay is opened, the normally closed contact is closed, and the risk of overcharging occurs again.

Further, as shown in FIG. 4, the first voltage detecting circuit 10 can be connected to the first self-locking circuit 20 through the first filter circuit 30. The first filter circuit 30 can include a twelfth resistor R12 and a fourth capacitor C4. The one end of the twelfth resistor R12 is connected to the first voltage detecting circuit 10. One end of the fourth capacitor C4 is connected to the other end of the twelfth resistor R12 and the first self-locking circuit 20, and the other end of the fourth capacitor C4 is grounded to GND. The RC filter circuit formed by the twelfth resistor R12 and the fourth capacitor C4 filters out the boundary interference signal, thereby effectively improving the stability of the circuit.

Therefore, the overcharge protection circuit of the power battery according to the embodiment of the present invention controls the charging control circuit to be in an off state by the self-locking function of the circuit when the voltage of the power battery is greater than the first reference voltage, thereby effectively avoiding the power battery. Overcharge occurs, and after the power battery reaches full charge, in the absence of current, the voltage of the power battery automatically falls to the first reference voltage, and the risk of overcharging occurs again, effectively improving the service life of the power battery.

Further, according to an embodiment of the present invention, as shown in FIG. 5, the first voltage detecting circuit 10 may include a first comparator P1, a fourth resistor R4, a fifth resistor R5, a first temperature compensation circuit 40, and a first Optocoupler U1. The positive input end of the first comparator P1 is connected to the positive pole of the battery Battery, and the output end of the first comparator P1 is connected to the first preset power source VCC1 through the fourth resistor R4, and one end of the fifth resistor R5 is first The preset power source VCC1 is connected, and the other end of the fifth resistor R5 is connected to the negative input terminal of the first comparator P1. One end of the first temperature compensation circuit 40 is respectively connected to the negative input end of the first comparator P1 and the other end of the fifth resistor R5, and the other end of the first temperature compensation circuit 40 is connected to the negative pole of the battery of the power battery, the first temperature compensation The voltage at one end of the circuit 40 is the first reference voltage. The first input end of the first optocoupler U1 is connected to the output end of the first comparator P1, the second input end of the first optocoupler U1 is connected to the first ground end GND1, and the first output end of the first optocoupler U1 is The second preset power source VCC2 is connected, and the second output end of the first photocoupler U1 is connected to the first self-locking circuit 20.

Further, the first temperature compensation circuit 40 may include a first PTC (Positive Temperature Coefficient) module PTC1. The first PTC module PTC1 may be composed of one or more PTC resistors, or may be composed of a resistor and a PTC resistor, and may be set according to actual conditions.

Specifically, since the battery of the power battery is greatly affected by the temperature, the overcharge protection voltage point of the battery of the power battery is different at different temperatures. If the fixed reference voltage is compared with the voltage of the battery of the power battery, the power battery is overcharged. Inaccurate, therefore, the reference voltage can be temperature compensated so that the temperature compensated reference voltage matches the actual overcharge protection voltage point of the power battery at the current ambient temperature, and then the temperature compensated reference voltage pair The power battery is judged.

Specifically, as shown in FIG. 5, the first reference voltage can be obtained by dividing the first PTC module PTC1, and the first PTC module PTC1 can select a thermistor having a positive temperature coefficient. When the first preset power source VCC1 is constant, in the high temperature environment, the resistance value of the first PTC module PTC1 will become larger, and the first reference voltage will be correspondingly higher, thereby being able to satisfy the high temperature environment. The charging voltage of the battery of the battery is increased; in the low temperature environment, the resistance of the first PTC module PTC1 becomes smaller, and the first reference voltage is correspondingly smaller, thereby being able to satisfy the charging voltage reduction of the battery of the power battery in a low temperature environment. Case. Therefore, by the temperature compensation of the PTC resistor in the first temperature compensation circuit 40, the first reference voltage can be matched with the overcharge voltage protection point corresponding to the actual power battery at the current ambient temperature, thereby making the overcharge determination of the power battery more accurate.

Further, as shown in FIG. 5, the positive input end of the first comparator P1 is connected to the positive pole of the battery of the power battery to detect the voltage of the battery of the power battery in real time, while the negative input terminal of the first comparator P1 obtains the first reference voltage. .

During the battery charging process of the power battery, when the power battery Battery does not overcharge, the voltage of the positive input terminal of the first comparator P1 is lower than the voltage of the negative input terminal, and the first comparator P1 outputs a low level signal, and the first optical coupler No current flows through the front end of U1. At this time, the voltage of the second preset power supply VCC2 is mainly applied between the first output end and the second output end of the first photocoupler U1, and the first MOS transistor Q1 is in an off state. No current flows in the coil K1M of a relay K1, the first relay K1 does not operate, the charging control circuit 200 is in a closed state, and the battery of the power battery is normally charged.

When the power battery Battery is overcharged, the voltage of the positive input terminal of the first comparator P1 is higher than the voltage of the negative input terminal, and the first comparator P1 outputs a high level signal. Under the action of the high level, the first optocoupler U1 is driven, the voltage between the first output end and the second output end of the first optocoupler U1 is almost 0, and the voltage of the second preset power source VCC2 is all applied At one end of the first resistor R1, at this time, the first MOS transistor Q1 is in an on state, a current flows through the coil K1M of the first relay K1, the normally closed contact K12 of the first relay K1 is turned off, and the charging control circuit 200 is turned Disconnected, the battery of the power battery stops charging, thereby achieving overcharge protection of the power battery. At the same time, the normally open contact K11 of the first relay K1 is also closed, because one end of the normally open contact of the first relay K1 and the first light The second output end of the coupling U1 is connected, and the other end is connected to the second preset power source VCC2. Therefore, after the normally open contact K11 is closed, the current of the second preset power source VCC2 flows to the first light through the normally open contact K11. The second output end of the U1 is coupled, so that even if no current flows through the front end of the first photocoupler U1, the first MOS transistor Q1 is still in a conducting state, thereby realizing the self-locking function of the circuit, effectively preventing the power battery from reaching full charge. In the absence of current, the voltage of the power battery is self-contained Dropped after the first reference voltage, the relay normally open contacts, the normally closed contact is closed, and again a risk of the occurrence of charge.

It should be noted that, in practical applications, the overcharge protection voltage point of the battery of the power battery at different ambient temperatures may be obtained through experimental tests, and then the first reference voltage and the first temperature compensation circuit 40 are determined according to the overcharge protection voltage point. The relevant parameters are such that the first reference voltage output by the first temperature compensation circuit 40 is more consistent with the actual one, thereby making the determination more accurate.

Further, as shown in FIG. 5, the above-mentioned overcharge protection circuit of the power battery may further include a first DC/DC isolated power supply module 50, and the first DC/DC isolated power supply module 50 is configured to convert the second preset power supply VCC2. It is a first preset power source VCC1, and isolates the first preset power source VCC1 and the second preset power source VCC2.

Specifically, the main function of the DC/DC isolated power module 50 is to supply power to the first comparator P1 and the fourth resistor R4. At the same time, the first reference voltage is provided for the negative input terminal of the first comparator P1, and the high voltage region of the power battery and the low voltage region of the self-locking circuit are also isolated to further improve the safety of the system.

Therefore, according to the overcharge protection circuit of the power battery of the present invention, the reference voltage matching the overcharge protection voltage point of the power battery at the current ambient temperature is output through the temperature compensation circuit, and the reference voltage is used to determine whether the power battery has occurred. Charging can not only effectively solve the problem of temperature drift of components, but also have the ability to automatically adjust the reference voltage under different ambient temperatures, so that the judgment is more accurate, and thus the service life of the power battery is effectively improved.

According to another embodiment of the present invention, as shown in FIG. 6, the first voltage detecting circuit 10 may include a Zener diode D1, a third photocoupler U3, a fifteenth resistor R15, a sixteenth resistor R16, and a first temperature compensation. Circuit 40. The cathode of the Zener diode D1 is connected to the first temperature compensation circuit 40. The first input end of the third optocoupler U3 is connected to the anode of the Zener diode D1, and the second input end of the third optocoupler U3 is connected to the cathode of the battery Battery. One end of the fifteenth resistor R15 is connected to the first output end of the third photocoupler U3, and the other end of the fifteenth resistor R15 is connected to the first temperature compensating circuit 40. One end of the sixteenth resistor R16 is respectively connected to the second output end of the third photocoupler U3 and the first self-locking circuit 20, and the other end of the sixteenth resistor R16 is grounded to GND.

Further, as shown in FIG. 6, the first temperature compensation circuit 40 may include a third PTC module PTC3 and a fourth PTC module PTC4. Wherein, one end of the third PTC module PTC3 is connected to the cathode of the Zener diode D1, and the other end of the third PTC module PTC3 is connected to the anode of the power battery Battery. One end of the fourth PTC module PTC4 is connected to the other end of the fifteenth resistor R15, and the other end of the fourth PTC module PTC4 is connected to the preset power source VCC.

In the embodiment of the present invention, the third PTC module PTC3 may also be disposed between the second input end of the third optocoupler U3 and the negative pole of the power battery Battery, and the fourth PTC module PTC4 may also be disposed on the third optocoupler U3. Between the second output end and the ground GND, the specific setting position can be set according to actual conditions, and the third PTC module PTC3 and the fourth PTC module PTC4 can be composed of one or more PTC resistors, or can be composed of common resistors and The composition of the PTC resistor can be set according to the actual situation.

Specifically, as shown in FIG. 6, since the temperature drift phenomenon exists between the Zener diode D1 and the third photocoupler U3, the temperature is greatly affected. When the input voltage of the front end of the third photocoupler U3 is the same, the temperature is stabilized in a low temperature environment. The conduction voltage drop of the pressure tube D1 and the third photocoupler U3 is increased relative to the normal temperature or high temperature environment. Therefore, the current value flowing through the front end of the third photocoupler U3 is smaller than the current value in the normal temperature or high temperature environment.

If the front end of the third optocoupler U3 adopts the common resistor R, the current value IF1=(UB-UD1-U12)/R flowing through the front end of the third optocoupler U3, where UB is the voltage of the battery of the power battery, and UD1 is the voltage regulator. The conduction voltage drop of the tube D1, U12 is the conduction voltage drop of the third photocoupler U3. In the low temperature environment, the conduction voltage drop UD1 of the Zener diode D1 will rise, and the conduction voltage drop U12 of the third photocoupler U3 will also rise, and the resistance of the ordinary resistor R in the low temperature environment changes very much. It is small or almost constant. Therefore, in the case where the voltage UB of the power battery Battery is constant, the current value IF1 flowing through the front end of the third photocoupler U3 is lowered.

If the ordinary resistor R is replaced by the third PTC module PTC3 (in the embodiment, a single PTC resistor is taken as an example), the current value IF2=(UB-UD1-U12)/RPTC1 flowing through the front end of the third photocoupler U3, wherein RPTC1 is the resistance of the third PTC module PTC3. In the low temperature environment, although the conduction voltage drop UD1 of the Zener diode D1 and the conduction voltage drop U12 of the third photocoupler U3 are both increased, the resistance value RPTC1 of the third PTC module PTC3 is lowered in a low temperature environment. Therefore, the current value IF2>IF1 of the front end of the third photocoupler U3 realizes temperature compensation of the front end of the third photocoupler U3 in a low temperature environment.

In a high temperature environment, the conduction voltage drop of the Zener diode D1 and the third photocoupler U3 will become smaller, that is, both UD1 and U12 are lowered, and the resistance of the ordinary resistor R in a high temperature environment is small or almost constant. In the case where the voltage UB of the power battery Battery is constant, the current value IF1 flowing through the front end of the third photocoupler U3 rises. If the ordinary resistor R is replaced by the third PTC module PTC3, in the high temperature environment, although the conduction voltage drop UD1 of the Zener diode D1 and the conduction voltage drop U12 of the third photocoupler U3 are both lowered, the third PTC The resistance value RPTC1 of the module PTC3 rises in a high temperature environment. Therefore, the current value IF2<IF1 of the front end of the third photocoupler U3 realizes temperature compensation for the front end of the third photocoupler U3 in a high temperature environment.

Therefore, in the case where the voltage UB of the battery of the power battery is constant, even if the ambient temperature changes, the current value of the front end of the third photocoupler U3 changes little due to the action of the third PTC module PTC3, thereby realizing the optocoupler. The temperature compensation of the voltage regulator tube improves the detection accuracy of the voltage detection circuit, thereby improving the accuracy and reliability of the overcharge protection of the power battery.

Further, as shown in FIG. 6, the voltage UF at the rear end of the third photocoupler U3 has a linear relationship with the front end current IF, that is, UF=β*IF, where β is a coefficient, and therefore, whether the first self-locking circuit 20 can There is a proportional relationship between the work and the voltage UB of the battery of the power battery. In addition, since the first self-locking circuit 20 is composed of a MOS transistor and other components, the MOS transistor has a temperature drift phenomenon.

If the back end of the third photocoupler U3 uses a common resistor R, the gate-source voltage of the second MOS transistor Q2

Due to the temperature drift phenomenon of the second MOS transistor Q2 in a low temperature environment, the gate-source voltage Ugs of the second MOS transistor Q2 will rise, and the resistance change of the ordinary resistor R in a low-temperature environment is small or almost constant, so In order to enable the second MOS transistor Q2 to be turned on, only β*IF is reduced, that is, only the voltage UB of the power battery Battery is reduced.

If the ordinary resistor R is replaced by the fourth PTC module PTC4 (in the embodiment, a single PTC resistor is taken as an example), the gate-source voltage of the second MOS transistor Q2

Wherein, RPTC2 is the resistance of the fourth PTC module PTC4. In the case of low temperature, since the resistance value RPTC2 of the fourth PTC module PTC4 is lowered, the gate-source voltage Ugs of the second MOS transistor Q2 is correspondingly increased, so that a UB value consistent with the normal temperature appears to drive the first The two MOS transistors Q2 are turned on, thereby realizing the compensation of the temperature drift caused by the second MOS transistor Q2 in a low temperature environment.

In a high temperature environment, the gate-source voltage Ugs of the second MOS transistor Q2 is lowered. If the back end of the third optocoupler U3 uses a common resistor R, then

It can be seen that when β*IF is lower than the value at normal temperature, that is, the voltage UB of the power battery Battery is lower than the voltage at normal temperature, the second MOS transistor Q2 is driven to be turned on. If the ordinary resistor R is replaced by the fourth PTC module PTC4, in the high temperature environment, since the resistance value RPTC2 of the fourth PTC module PTC4 will rise, the gate-source voltage Ugs of the second MOS transistor Q2 will be correspondingly lowered, thus A UB value consistent with the normal temperature occurs, thereby compensating for the temperature drift caused by the second MOS transistor Q2 in a high temperature environment.

In summary, the temperature compensating circuit 40 composed of the third PTC module PTC3 and the fourth PTC module PTC4 can well solve the first voltage detecting circuit 10 and the first self-locking circuit 20 in the Zener diode D1 and the third photocoupler. The temperature drift problem caused by U3 and the second MOS transistor Q2, thereby realizing the automatic adjustment of the voltage threshold of the power battery under different temperature environments, that is, in different temperature environments, only when the voltage UB of the power battery Battery reaches the corresponding voltage threshold, The second MOS transistor Q2 is turned on, so that the second relay K2 operates to improve the stability of the circuit. In addition, by the temperature compensation of the first voltage detecting circuit 10, the charging characteristics of the power battery under different ambient temperatures can also be satisfied, that is, in a low temperature environment, the power battery charging cut-off charging to the full state voltage will be correspondingly lower; The power battery will be charged up to full state voltage will be higher.

In summary, according to the overcharge protection circuit of the power battery of the present invention, temperature compensation of the reference voltage by the temperature compensation circuit can not only accurately determine whether the power battery is overcharged, but also when the power battery is overcharged. The self-locking function of the circuit controls the charging control loop to be in the off state all the time, thereby effectively preventing the power battery from being repeatedly overcharged, thereby greatly improving the service life of the power battery.

Figure 7 is a block diagram of an over-discharge protection circuit for a power battery in accordance with one embodiment of the present invention. As shown in FIG. 7, the over-discharge protection circuit of the power battery may include a second voltage detection circuit 60 and a second self-locking circuit 70.

The second voltage detecting circuit 60 is connected to the battery of the power battery. The second voltage detecting circuit 60 is configured to detect the voltage of the battery of the power battery, and output an over-discharge protection signal when the voltage of the battery of the power battery is less than the second reference voltage. The self-locking circuit 70 is connected to the second voltage detecting circuit 60 and the discharging control circuit 300, respectively, and the second self-locking circuit 70 is configured to control the discharging control circuit 300 to be in an off state after receiving the over-discharge protection signal.

According to an embodiment of the present invention, as shown in FIG. 8, the second self-locking circuit 70 may include a sixth resistor R6, a fifth MOS transistor Q5, and a third relay K3. One end of the sixth resistor R6 is connected to the second voltage detecting circuit 60, the gate of the fifth MOS transistor Q5 is connected to the other end of the sixth resistor R6, and the source of the fifth MOS transistor Q5 is connected to the second ground GND2. The drain of the fifth MOS transistor Q5 is connected to one end of the sixth resistor R6. One end of the coil K3M of the third relay K3 is respectively connected to the drain of the fifth MOS transistor Q5, one end of the sixth resistor R6, and one end of the normally open contact K31 of the third relay K3, and the other of the coil K3M of the third relay K3 One end is connected to the other end of the normally open contact K31 of the second preset power source VCC2 and the third relay K3, respectively, and both ends of the normally closed contact K32 of the third relay K3 are connected in the discharge control circuit 300.

Further, as shown in FIG. 8, the above-mentioned over-current protection circuit of the power battery may further include a second filter circuit 80, and the second filter circuit 80 may include a thirteenth resistor R13 and a fifth capacitor C5. Wherein, one end of the thirteenth resistor R13 is connected to the gate of the fifth MOS transistor, the other end of the thirteenth resistor R13 is connected to the second ground GND2, and the fifth capacitor C5 and the tenth The three resistors R13 are connected in parallel. The thirteenth resistor R13 and the fifth capacitor C5 form an RC filter circuit to eliminate external interference and ensure control stability.

According to another embodiment of the present invention, as shown in FIG. 9, the second self-locking circuit 70 may include a sixth MOS transistor Q6, a seventh MOS transistor Q7, an eighth MOS transistor Q8, a seventh resistor R7, and an eighth resistor R8. The second capacitor C2 and the fourth relay K4. The gate of the sixth MOS transistor Q6 is connected to the second voltage detecting circuit 60, the source of the sixth MOS transistor Q6 is grounded to GND, and the gate of the seventh MOS transistor Q7 is connected to the drain of the sixth MOS transistor Q6. The gate of the seventh MOS transistor Q7 is also connected to the preset power supply VCC through the seventh resistor R7, the source of the seventh MOS transistor Q7 is grounded to GND, and the gate of the eighth MOS transistor Q8 is connected to the drain of the seventh MOS transistor Q7. The gate of the eighth MOS transistor Q8 is also connected to the preset power supply VCC through the eighth resistor R8, the source of the eighth MOS transistor Q8 is grounded to GND, and the source of the eighth MOS transistor Q8 is also passed through the second capacitor C2 and the eighth MOS. The gate of the tube Q8 is connected. One end of the coil K4M of the fourth relay K4 is connected to the drain of the eighth MOS transistor Q8, the other end of the coil K4M of the fourth relay K4 is connected to the preset power source VCC, and one end of the normally open contact K41 of the fourth relay K4 is The gate of the seventh MOS transistor Q7 is connected, the other end of the normally open contact K41 of the fourth relay K4 is grounded to GND, and both ends of the normally closed contact K42 of the fourth relay K4 are connected to the discharge control circuit 300.

Further, as shown in FIG. 9, the second voltage detecting circuit 60 can be connected to the second self-locking circuit 70 through the second filter circuit 90, and the second filter circuit 90 can include a fourteenth resistor R14 and a sixth capacitor C6, wherein One end of the fourteenth resistor R14 is connected to the second voltage detecting circuit 60. One end of the sixth capacitor C6 is connected to the other end of the fourteenth resistor R14 and the second latch circuit 70, and the other end of the sixth capacitor C6 is grounded. GND. The fourteenth resistor R14 and the sixth capacitor C6 form an RC filter circuit to eliminate external interference and ensure control stability.

According to an embodiment of the present invention, as shown in FIG. 10, the second voltage detecting circuit 60 may include a second comparator P2, a ninth resistor R9, a tenth resistor R10, a second temperature compensation circuit 90, and a second photocoupler U2. . The negative input end of the second comparator P2 is connected to the positive pole of the battery Battery, and the output end of the second comparator P2 is connected to the first preset power source VCC1 through the ninth resistor R9, and one end of the tenth resistor R10 is first The preset power supply VCC1 is connected, the other end of the tenth resistor R10 is connected to the positive input end of the second comparator P2, and one end of the second temperature compensation circuit 90 is respectively connected with the positive input end of the second comparator P2 and the tenth resistor R10. The other end is connected, the other end of the second temperature compensation circuit 90 is connected to the negative pole of the battery Battery, and the voltage of one end of the second temperature compensation circuit 90 is the second reference voltage. The first input end of the second optocoupler U2 is connected to the output end of the second comparator P2, the second input end of the second optocoupler U2 is connected to the first ground end GND1, and the first output end of the second optocoupler U2 is The second preset power source VCC2 is connected, and the second output end of the second photocoupler U2 is connected to the second self-locking circuit 70.

Further, as shown in FIG. 10, the second temperature compensation circuit 90 may include a second PTC module PTC2, which may be composed of one or more PTC resistors, or may be composed of a resistor and a PTC resistor, depending on Set the actual situation.

Specifically, as shown in FIG. 10, the negative input terminal of the second comparator P2 is connected to the positive pole of the battery of the power battery, The voltage of the power battery Battery is detected in real time while the positive input terminal of the second comparator P2 acquires the second reference voltage.

During the battery battery discharge process, when the power battery Battery does not appear over-discharged, the voltage of the positive input terminal of the second comparator P2 is lower than the voltage of the negative input terminal, and the second comparator P2 outputs a low-level signal, and the second photocoupler No current flows through the front end of the U2. At this time, the voltage of the second preset power supply VCC2 is mainly applied between the first output end and the second output end of the second photocoupler U2, and the fifth MOS transistor Q5 is in the off state. No current flows through the coil K3M of the three relay K3, the third relay K3 does not operate, the discharge control circuit 300 is in a closed state, and the battery of the power battery is normally discharged.

When the power battery is over-discharged, the voltage of the positive input terminal of the second comparator P2 is higher than the voltage of the negative input terminal, and the second comparator P2 outputs a high-level signal. Under the action of the high level, the second photocoupler U2 is driven, the voltage between the first output end and the second output end of the second photocoupler U2 is almost 0, and the voltage of the second preset power source VCC2 is all applied On one end of the sixth resistor R6, at this time, the fifth MOS transistor Q5 is in an on state, a current flows through the coil K3M of the third relay K3, the normally closed contact K32 of the third relay K3 is turned off, and the discharge control circuit 300 is turned off. Disconnected, the battery of the power battery stops discharging, thereby achieving over-discharge protection of the power battery. At the same time, the normally open contact K31 of the third relay K3 is also closed, due to the end of the normally open contact K31 of the third relay K3 and the second The second output end of the optocoupler U2 is connected, and the other end is connected to the second preset power source VCC2. Therefore, after the normally open contact K31 is closed, the current of the second preset power source VCC2 flows to the second through the normally open contact K31. The second output end of the optocoupler U2, so that even if no current flows through the front end of the second photocoupler U2, the fifth MOS transistor Q5 is still in a conducting state, thereby realizing the self-locking function of the circuit, effectively avoiding the situation that the power battery is not discharged. Next, the voltage of the power battery will automatically rise by several tens of mV. , causing the normally open contact of the relay to open, the normally closed contact to close, and the risk of overdischarge occurring again.

Further, as shown in FIG. 10, the above-mentioned over-current protection circuit of the power battery further includes a second DC/DC isolated power supply module 100, and the second DC/DC isolated power supply module 100 is configured to convert the second preset power supply VCC2 into The first preset power source VCC1 isolates the first preset power source VCC1 and the second preset power source VCC2.

It should be noted that the over-discharge protection circuit of the power battery of the embodiment of the present invention is similar to the over-charge protection circuit. For details not disclosed in the over-discharge protection circuit of the power battery of the embodiment of the present invention, reference may be made to the embodiment of the present invention. The details disclosed in the charging protection circuit will not be described here.

In summary, according to the over-discharge protection circuit of the power battery of the present invention, temperature compensation of the reference voltage by the temperature compensation circuit can not only accurately determine whether the power battery is over-discharged, but also when the power battery is over-discharged. The self-locking function of the circuit controls the discharge control loop to be in the off state all the time, thereby effectively preventing the power battery from being repeatedly over-discharged, thereby greatly improving the service life of the power battery.

Figure 11 is a circuit diagram of a charge and discharge protection device for a power battery according to an embodiment of the present invention. As shown in FIG. 11, the charge and discharge protection device 1000 of the power battery may include the above-described overcharge protection circuit and over discharge protection circuit of the power battery.

Wherein one end of the normally closed contact K32 of the third relay K3 is opposite to one end of the normally closed contact K12 of the first relay K1. Further, the other end of the normally closed contact of the third relay K3 is connected to one end of the charge and discharge control circuit 400, and the other end of the normally closed contact K12 of the first relay K1 is connected to the other end of the charge and discharge control circuit 400. In the battery charging and discharging process of the power battery, as long as overcharge or overdischarge occurs, the circuit will automatically cut off the charge and discharge control circuit 400 to realize protection of the power battery, which will not be described in detail herein.

Further, as shown in FIG. 12, the above-described charge and discharge protection device 1000 of the power battery may further include a protection relay Kb, and the device is connected in series in the power battery pack 2000. The battery voltage is detected in real time by the charging protection circuit and the discharge protection circuit. When the battery voltage exceeds the protection threshold of the hardware circuit design, the protection relay Kb is directly disconnected, thereby achieving overcharge and overdischarge protection for the power battery pack 2000. Moreover, the entire overcharge and overdischarge protection is realized by hardware circuit, no software is needed for judgment, and has temperature compensation function, which effectively improves the speed, accuracy and reliability of overcharge and overdischarge protection.

According to the charge and discharge protection device for a power battery according to the present invention, the overcharge protection circuit and the over discharge protection circuit of the power battery can effectively prevent overcharging of the power battery, and prevent the power battery from reaching a full charge after the battery is fully charged. In the case that the voltage of the power battery automatically falls to the first reference voltage, the risk of overcharging occurs again, and the power battery can be effectively prevented from being over-discharged, and the voltage of the power battery is automatically raised when the power battery is not discharged. A few tens of mV high causes the normally open contact of the relay to open, the normally closed contact to close, and the risk of overdischarge occurring again.

Figure 13 is a schematic illustration of a battery management system in accordance with one embodiment of the present invention. As shown in FIG. 13, the battery management system 3000 may include the above-described charge and discharge protection device 1000 of the power battery.

Specifically, as shown in FIG. 13, the existing battery management system 3000 can perform overcharge and overdischarge protection on the power battery pack 2000 together with the above-described charge and discharge protection device 1000, wherein the existing battery management system can be As the first-stage safety protection system, the charging and discharging protection device 1000 of the embodiment of the present invention is used as the second-level safety protection system, thereby further reducing the risk of overcharging and over-discharging of the power battery pack 2000.

Specifically, as shown in FIG. 13, the charge and discharge protection device 1000 can be integrated in the interior of the power battery pack 2000, and the voltage across the battery is directly obtained by the charge and discharge protection device 1000. When the voltage across the battery exceeds the protection of the hardware circuit setting. At the threshold, the protection relay Kb is directly disconnected, thereby disconnecting the charge and discharge circuit of the entire power battery, thereby effectively avoiding the risk of overcharging and overdischarging of the battery due to failure of the battery management system.

According to the battery management system of the present invention, the above-mentioned charge and discharge protection device of the power battery can effectively prevent the power battery from being overcharged, and at the same time, after the power battery reaches full charge, the voltage of the power battery is automatically lost in the absence of current. After the first reference voltage, the risk of overcharging occurs again, and the over-discharge of the power battery can be effectively avoided, and the voltage of the power battery is automatically increased by several tens of mV without causing the power battery to be discharged, resulting in frequent relays. The open contact is open and the normally closed contact is closed, and the risk of overdischarge occurs again.

Further, an embodiment of the present invention also proposes an electric vehicle including the above-described charge and discharge protection device for a power battery.

According to the automobile of the present invention, the above-mentioned charging and discharging protection device for the power battery can effectively prevent the power battery from being emitted. When the battery is overcharged, and the power battery is not fully charged, in the absence of current, the voltage of the power battery automatically falls to the first reference voltage, and the risk of overcharging occurs again, and the power battery can be effectively prevented from being over-discharged. At the same time, if the power battery is not discharged, the voltage of the power battery will automatically rise by several tens of mV, causing the normally open contact of the relay to be disconnected, and the normally closed contact to be closed, and the risk of overdischarge occurring again.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " After, "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship of the "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present invention and simplified description, and does not indicate or imply the indicated device or component. It must be constructed and operated in a particular orientation, and is not to be construed as limiting the invention.

Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include at least one of the features, either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless specifically defined otherwise.

In the present invention, the terms "installation", "connected", "connected", "fixed" and the like shall be understood broadly, and may be either a fixed connection or a detachable connection, unless explicitly stated and defined otherwise. , or integrated; can be mechanical or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction of two elements, unless otherwise specified Limited. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

In the present invention, the first feature "on" or "under" the second feature may be a direct contact of the first and second features, or the first and second features may be indirectly through an intermediate medium, unless otherwise explicitly stated and defined. contact. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or above the second feature, or merely that the first feature level is higher than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely that the first feature level is less than the second feature.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

An overcharge protection circuit for a power battery, comprising:

a first voltage detecting circuit, the first voltage detecting circuit is connected to the power battery, the first voltage detecting circuit is configured to detect a voltage of the power battery, and output when the voltage of the power battery is greater than the first reference voltage Overcharge protection signal;

a first self-locking circuit, wherein the first self-locking circuit is respectively connected to the first voltage detecting circuit and a charging control circuit, wherein the first self-locking circuit is configured to control the after-receiving signal after receiving the over-charge protection signal The charge control loop is in the off state.
The overcharge protection circuit for a power battery according to claim 1, wherein the first self-locking circuit comprises:

a first resistor, one end of the first resistor is connected to the first voltage detecting circuit;

a first MOS transistor, a gate of the first MOS transistor is connected to another end of the first resistor, a source of the first MOS transistor is connected to a second ground, and a drain of the first MOS transistor Connected to one end of the first resistor;

a first relay, one end of the coil of the first relay is respectively connected to a drain of the first MOS transistor, one end of the first resistor, and one end of a normally open contact of the first relay, The other end of the coil of a relay is respectively connected to the second preset power source and the other end of the normally open contact of the first relay, and both ends of the normally closed contact of the first relay are connected to the charging control loop in.
The overcharge protection circuit for a power battery according to claim 1, wherein the first self-locking circuit comprises: a second MOS transistor, a third MOS transistor, a fourth MOS transistor, a second resistor, and a third resistor a first capacitor and a second relay; wherein

a gate of the second MOS transistor is connected to the first voltage detecting circuit, and a source of the second MOS transistor is grounded;

a gate of the third MOS transistor is connected to a drain of the second MOS transistor, and a gate of the third MOS transistor is further connected to a preset power source through a second resistor, a source of the third MOS transistor Pick up the ground;

a gate of the fourth MOS transistor is connected to a drain of the third MOS transistor, and a gate of the fourth MOS transistor is further connected to the preset power source through a third resistor, the fourth MOS transistor The source is connected to the ground, and the source of the fourth MOS transistor is further connected to the gate of the fourth MOS transistor through a first capacitor;

One end of the coil of the second relay is connected to the drain of the fourth MOS tube, and the other end of the coil of the second relay is connected to the preset power source, and the normally open contact of the second relay One end is connected to the gate of the third MOS tube, the other end of the normally open contact of the second relay is connected to the ground, and both ends of the normally closed contact of the second relay are connected to the charging control In the loop.
The overcharge protection circuit for a power battery according to claim 2, wherein the first voltage detecting circuit comprises: a first comparator, a fourth resistor, a fifth resistor, a first temperature compensation circuit, and a first light Coupling; among them,

The positive input end of the first comparator is connected to the positive pole of the power battery, and the output end of the first comparator is connected to the first preset power source through a fourth resistor;

One end of the fifth resistor is connected to the first preset power source, and the other end of the fifth resistor is connected to a negative input end of the first comparator;

One end of the first temperature compensation circuit is respectively connected to a negative input end of the first comparator and another end of the fifth resistor, and the other end of the first temperature compensation circuit is connected to a negative pole of the power battery The voltage of one end of the first temperature compensation circuit is the first reference voltage;

a first input end of the first optocoupler is connected to an output end of the first comparator, a second input end of the first optocoupler is connected to a first ground end, and a first end of the first optocoupler The output end is connected to the second preset power source, and the second output end of the first optocoupler is connected to the first self-locking circuit.
The overcharge protection circuit for a power battery according to claim 4, wherein said first temperature compensation circuit comprises a first PTC module.
The overcharge protection circuit for a power battery according to claim 4 or 5, further comprising a first DC/DC isolated power supply module, wherein the first DC/DC isolated power supply module is configured to use the second pre- The power source is converted into the first preset power source, and the first preset power source and the second preset power source are isolated.
The overcharge protection circuit for a power battery according to claim 3, wherein said first voltage detecting circuit comprises: a Zener diode, a third photocoupler, a fifteenth resistor, a sixteenth resistor, and a first temperature Compensation circuit; among them,

The cathode of the Zener tube is connected to the first temperature compensation circuit;

a first input end of the third optocoupler is connected to the anode of the Zener diode, and a second input end of the third optocoupler is connected to the negative pole of the power battery;

One end of the fifteenth resistor is connected to the first output end of the third optocoupler, and the other end of the fifteenth resistor is connected to the first temperature compensating circuit;

One end of the sixteenth resistor is respectively connected to the second output end of the third photocoupler and the first self-locking circuit, and the other end of the sixteenth resistor is grounded.
The overcharge protection circuit for a power battery according to claim 7, wherein the first temperature compensation circuit comprises a third PTC module and a fourth PTC module;

One end of the third PTC module is connected to the cathode of the Zener tube, and the other end of the third PTC module is connected to the anode of the power battery;

One end of the fourth PTC module is connected to the other end of the fifteenth resistor, and the other end of the fourth PTC module is connected to a preset power source.
An over-discharge protection circuit for a power battery, comprising:

a second voltage detecting circuit, the second voltage detecting circuit is connected to the power battery, and the second voltage detecting circuit is used In order to detect the voltage of the power battery, and output an over-discharge protection signal when the voltage of the power battery is less than the second reference voltage;

a second self-locking circuit, wherein the second self-locking circuit is respectively connected to the second voltage detecting circuit and the discharging control circuit, wherein the second self-locking circuit is configured to control the after-receiving signal after receiving the over-discharge protection signal The discharge control loop is in the off state.
The over-discharge protection circuit for a power battery according to claim 9, wherein the second self-locking circuit comprises:

a sixth resistor, one end of the sixth resistor is connected to the second voltage detecting circuit;

a fifth MOS transistor, a gate of the fifth MOS transistor is connected to another end of the sixth resistor, a source of the fifth MOS transistor is connected to a second ground, and a drain of the second MOS transistor Connected to one end of the sixth resistor;

a third relay, one end of the coil of the third relay is respectively connected to a drain of the fifth MOS transistor, one end of the sixth resistor, and one end of a normally open contact of the third relay, respectively The other ends of the coils of the three relays are respectively connected to the second preset power source and the other end of the normally open contact of the third relay, and the two ends of the normally closed contacts of the third relay are connected to the discharge control loop in.
The over-discharge protection circuit for a power battery according to claim 9, wherein the second self-locking circuit comprises: a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a seventh resistor, and an eighth resistor a second capacitor and a fourth relay; wherein

a gate of the sixth MOS transistor is connected to the second voltage detecting circuit, and a source of the sixth MOS transistor is grounded;

a gate of the seventh MOS transistor is connected to a drain of the sixth MOS transistor, and a gate of the seventh MOS transistor is further connected to a preset power source through a seventh resistor, and a source of the seventh MOS transistor Pick up the ground;

a gate of the eighth MOS transistor is connected to a drain of the seventh MOS transistor, and a gate of the eighth MOS transistor is further connected to the preset power source through an eighth resistor, wherein the eighth MOS transistor The source is connected to the ground, and the source of the eighth MOS transistor is further connected to the gate of the eighth MOS transistor through a second capacitor;

One end of the coil of the fourth relay is connected to the drain of the eighth MOS tube, and the other end of the coil of the fourth relay is connected to the preset power source, and the normally open contact of the fourth relay One end is connected to the gate of the seventh MOS tube, the other end of the normally open contact of the fourth relay is connected to the ground, and both ends of the normally closed contact of the fourth relay are connected to the discharge control In the loop.
The over-current protection circuit for a power battery according to claim 10, wherein the second voltage detecting circuit comprises: a second comparator, a ninth resistor, a tenth resistor, a second temperature compensation circuit, and a second light Coupling; among them,

a negative input end of the second comparator is connected to a positive pole of the power battery, and an output end of the second comparator is connected to a first preset power source through a ninth resistor;

One end of the tenth resistor is connected to the first preset power source, and the other end of the tenth resistor is connected to a positive input end of the second comparator;

One end of the second temperature compensation circuit is respectively connected to a positive input end of the second comparator and another end of the tenth resistor, and the other end of the second temperature compensation circuit is connected to a negative pole of the power battery The voltage of one end of the second temperature compensation circuit is the second reference voltage;

a first input end of the second optocoupler is connected to an output end of the second comparator, a second input end of the second optocoupler is connected to the first ground end, and the first end of the second optocoupler The output end is connected to the second preset power source, and the second output end of the second photocoupler is connected to the second self-locking circuit.
The over-discharge protection circuit for a power battery according to claim 12, wherein said second temperature compensation circuit comprises a second PTC module.
The over-discharge protection circuit for a power battery according to claim 12 or 13, further comprising a second DC/DC isolated power supply module, wherein the second DC/DC isolated power supply module is configured to The power source is converted into the first preset power source, and the first preset power source and the second preset power source are isolated.
A charging and discharging protection device for a power battery, comprising:

An overcharge protection circuit for a power battery according to any one of claims 1-8;

An over-discharge protection circuit for a power battery according to any one of claims 9-14.
A battery management system comprising the charge and discharge protection device of the power battery according to claim 15.
An electric vehicle comprising the charge and discharge protection device of the power battery according to claim 15.