CN218122199U

CN218122199U - Protection shield MOSFET self-diagnostic circuit

Info

Publication number: CN218122199U
Application number: CN202221395864.4U
Authority: CN
Inventors: 王晓东; 郑玲珑; 张启立
Original assignee: Anhui Udan Technology Co ltd
Current assignee: Anhui Udan Technology Co ltd
Priority date: 2022-06-06
Filing date: 2022-06-06
Publication date: 2022-12-23
Anticipated expiration: 2032-06-06

Abstract

The utility model discloses a protection shield MOSFET self-diagnostic circuit belongs to battery management technical field. The utility model comprises a voltage acquisition module and a current excitation module, wherein in the current excitation module, the positive pole of a battery pack BT1 is connected with the S pole of an MOS tube Q2 through a switch SW1, the D pole of the MOS tube Q2 is connected with the D pole of the MOS tube Q1, and the S pole of the MOS tube Q1 is connected with the negative pole of the battery pack BT 1; the G pole of the MOS tube Q2 is connected to a charging control port of the protection plate AFE, and the G pole of the MOS tube Q1 is connected to a discharging control port of the protection plate AFE. The utility model discloses insert the excitation circuit of analog load in the guard plate circuit, insert voltage detection circuit simultaneously, utilize amplifier detection voltage, can detect out the short circuit and the state of opening circuit of charge and discharge MOS under the condition that does not insert the load, can send the early warning in advance, guaranteed the safety of battery.

Description

Protection board MOSFET self-diagnosis circuit

Technical Field

The utility model relates to a battery management technology field, more specifically say, relate to a protection shield MOSFET self-diagnosis circuit.

Background

Due to the rapid development of power lithium batteries in recent years, the production process and the material technology improvement have considerable breakthroughs, the lithium batteries are widely used in the fields of electric bicycles, backup power supplies and the like, the market share of the lithium batteries is continuously expanded, and the lithium batteries gradually replace the lead-acid batteries in daily life. For the safety and life of the battery, the lithium battery needs to be effectively protected, and the protection plate is an important component of the lithium battery.

The battery protection board refers to an integrated circuit board for protecting a rechargeable battery (generally, a lithium battery). Because the lithium battery cannot be overcharged, overdischarged, over-current, short-circuited and subjected to ultra-high-temperature charging and discharging due to the fact that the lithium battery is made of materials, a lithium battery assembly needs a protection board to detect and protect the lithium battery assembly.

The BMS system of the existing protection board (hardware protection board or software protection board) has insufficient diagnosis coverage for MOSFET failure, the MOSFET failure cannot be timely and effectively detected, and the battery is easy to be overcharged so as to be ignited and burnt; and it is easy to cause over-discharge of the battery, and the battery expands and the capacity is degraded.

The existing diagnosis method judges the failure of the MOSFET through a current detection strategy: if the current is still left after the MOSFET is closed, the MOSFET is considered to be short-circuited, and if the MOSFET is opened, no charging current exists, the MOSFET is considered to be open-circuited, and if the current collection fails, misjudgment is easily caused.

The Chinese patent number ZL201721375685.3, the date of the publication of the authorization is 6 and 1 in 2018, and the name of the invention creation is as follows: the utility model provides a detection system that lithium battery protection board overcharged and overdischarged, this application includes simulation battery module, simulation battery module passes through the wire and is connected with the battery core incoming end, the battery core incoming end passes through the wire and is connected with charge-discharge control MOSFET switch and battery protection chip respectively, charge-discharge control MOSFET switch passes through the wire and is connected with battery protection chip, charge-discharge control MOSFET switch and battery protection chip all are connected with the battery output through the wire, the battery output passes through the wire and is connected with load body module altogether with the program power, but be provided with along becoming the trigger on program power and the load body module altogether. The application is the existing method for detecting the MOSFET by using the current, and the misjudgment and the damage to the battery are easily caused when the current collection is invalid.

Disclosure of Invention

1. Technical problem to be solved by the utility model

In view of present MOSFET diagnostic method is mostly the current detection strategy, easily causes the erroneous judgement when the electric current collection became invalid to influence the problem of battery safety, the utility model discloses improve protection shield circuit, can detect the short circuit and the open circuit state of charge and discharge MOS under the condition of not inserting charger and vehicle, can send the early warning in advance, guaranteed the safety of battery.

2. Technical scheme

In order to achieve the above purpose, the utility model provides a technical scheme does:

the utility model discloses a protection shield MOSFET self-diagnosis circuit, including voltage acquisition module and current excitation module, in the current excitation module, battery package BT1 applys excitation current to the protection shield, voltage acquisition module and protection shield AFE electricity are connected; in the current excitation module, the positive electrode of a battery pack BT1 is connected to the S electrode of an MOS (metal oxide semiconductor) tube Q2 through a switch SW1, the D electrode of the MOS tube Q2 is connected to the D electrode of the MOS tube Q1, and the S electrode of the MOS tube Q1 is connected to the negative electrode of the battery pack BT 1; the G pole of the MOS tube Q2 is connected to a charging control port of the protection plate AFE, and the G pole of the MOS tube Q1 is connected to a discharging control port of the protection plate AFE.

Furthermore, a shunt R1 is arranged between the negative electrode of the battery pack BT1 and the MOS transistor Q1, and the negative electrode of the battery pack BT1 is grounded.

Furthermore, the voltage acquisition module comprises an amplifier U1, the positive input end of the amplifier U1 is connected with the S pole of an MOS tube Q2, and the voltage of the protection plate AFE is detected through the MOS tube Q2; the negative input end of the amplifier U1 is connected with the output end of the amplifier U1, and the output end of the amplifier U1 is connected with the display voltage of the display; the negative power supply end of the amplifier U1 is grounded, and the positive power supply end is connected with the MCU.

Furthermore, a current detection module is connected between the MOS transistor Q1 and the shunt R1 to detect the current of the shunt R1.

Furthermore, the current detection module comprises an amplifier U2, wherein the anode input end of the amplifier U2 is connected with the S pole of the MOS tube Q1, the cathode input end of the amplifier U2 is connected with the output end of the amplifier U2, and the output end of the amplifier U2 is connected with the display; the negative power supply end of the amplifier U2 is grounded, and the positive power supply end is connected with the MCU.

Furthermore, a load RLOAD is connected between the switch SW1 and the MOS tube Q2.

Furthermore, the MCU connected to the amplifier U1 and the amplifier U2 provides 3.3V voltage.

3. Advantageous effects

Adopt the technical scheme provided by the utility model, compare with existing well-known technique, have following beneficial effect:

(1) In view of present MOSFET diagnostic method is mostly the current detection strategy, easily causes the erroneous judgement when the electric current collection became invalid to influence the problem of battery safety, the utility model discloses insert the excitation circuit of analog load in the guard plate circuit, insert voltage detection circuit simultaneously, utilize amplifier detection voltage, can detect out the short circuit and the open circuit state of charge and discharge MOS under the condition of not inserting the load, can send the early warning in advance, guaranteed the safety of battery.

(2) The utility model discloses a protection shield MOSFET self-diagnosis circuit does not rely on current detection's mode, can judge whether the MOS pipe became invalid, thereby can effectually avoid the current acquisition inefficacy to lead to the problem of detection error. Simultaneously, both can detect under the circumstances of no load whether protection shield MOSFET breaks down, also can be under the circumstances of having the load, detect protection shield MOSFET at the during operation, can early warning in advance, also can detect the protection shield condition at any time at the during operation, can in time report to the police when the protection shield goes wrong, guaranteed battery and personnel's safety.

(3) The utility model discloses a protection shield MOSFET self-diagnosis circuit, when the charging and discharging MOS is closed, whether the load is connected to the charging device is detected by using the shunt; when the charging and discharging MOS is disconnected, the charger access detection circuit is used for detecting whether the load is connected to the charging device or not, whether the load is in a charging state or not can be detected at any time, and users can be reminded in time.

Drawings

Fig. 1 is a circuit diagram of the self-diagnosis system of the protection board of the present invention;

fig. 2 is a flow chart of the detection process of the present invention.

Detailed Description

For a further understanding of the present invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

Examples

With reference to fig. 1, the protection board MOSFET self-diagnostic circuit of this embodiment includes a voltage acquisition module and a current excitation module, where in the current excitation module, a battery pack BT1 applies an excitation current to a protection board, and the voltage acquisition module is electrically connected to a protection board AFE; in the current excitation module, the anode of a battery pack BT1 is connected to the S pole of an MOS (metal oxide semiconductor) transistor Q2 through a switch SW1, the D pole of the MOS transistor Q2 is connected to the D pole of the MOS transistor Q1, and the S pole of the MOS transistor Q1 is connected to the cathode of the battery pack BT 1; the G pole of the MOS tube Q2 is connected to a charging control port of the protection plate AFE, and the G pole of the MOS tube Q1 is connected to a discharging control port of the protection plate AFE. A shunt R1 is further arranged between the negative electrode of the battery pack BT1 and the MOS tube Q1, and the negative electrode of the battery pack BT1 is grounded. And a load RLOAD is connected between the switch SW1 and the MOS tube Q2.

The voltage acquisition module comprises an amplifier U1, the positive electrode input end of the amplifier U1 is connected with the S electrode of an MOS tube Q2, and the voltage of the protection plate AFE is detected through the MOS tube Q2; the negative input end of the amplifier U1 is connected with the output end of the amplifier U1, and the output end of the amplifier U1 is connected with the display voltage of the display; the negative power supply end of the amplifier U1 is grounded, and the positive power supply end is connected with the MCU. In the embodiment, the excitation circuit of the analog load is connected into the protection plate circuit, the voltage detection circuit is connected into the protection plate circuit, the AFE voltage of the protection plate is detected by using the amplifier, the short circuit and open circuit states of the charge and discharge MOS can be detected under the condition that the load is not connected, early warning can be sent out in advance, and the safety of the battery is ensured.

In this embodiment, a current detection module is further connected between the MOS transistor Q1 and the shunt R1 to detect the current of the shunt R1. The current detection module comprises an amplifier U2, the positive input end of the amplifier U2 is connected with the S pole of the MOS tube Q1, the negative input end of the amplifier U2 is connected with the output end of the amplifier U2, and the output end is connected with the display; the negative power supply end of the amplifier U2 is grounded, and the positive power supply end is connected with the MCU. The voltage of this embodiment detection shunt R1 reachs protection shield MOSFET's electric current through calculating, can be with the mode that does not rely on current detection, can judge whether the MOS pipe became invalid, thereby can effectually avoid the problem that current collection became invalid and lead to the detection error. Simultaneously, both can detect under the circumstances of no load whether protection shield MOSFET breaks down, also can be under the circumstances of having the load, detect protection shield MOSFET at the during operation, can early warning in advance, also can detect the protection shield condition at any time at the during operation, can in time report to the police when the protection shield goes wrong, guaranteed battery and personnel's safety. In this embodiment, the MCUs accessed by the amplifier U1 and the amplifier U2 both provide 3.3V voltage.

Referring to fig. 2, in the present embodiment, when self-diagnosis is performed, the switch SW1 is first closed, a load for excitation is generated,

1. and closing the MOS tubes Q1 and Q2, wherein under the normal condition, the Q1 and Q2 are conducted, the voltage of V1 is less than 1mv within 1mohm of internal resistance, and if the voltage of the read V1 is more than 100mv, the Q1/Q2 is considered to have open circuit abnormity.

2. Closing the MOS tube Q1, and disconnecting the MOS tube Q2, wherein under the normal condition, the MOS tube Q1 is conducted, the internal resistance is 1mohm, the MOS tube Q2 is disconnected, the exciting current flows through the body diode of the MOS tube Q2, the voltage drop of the body diode of the MOS tube Q2 is about 0.6V, and if the voltage of the read V1 is less than 0.4V, the MOS tube Q2 is considered to have short circuit abnormity.

3. And disconnecting the MOS tube Q1 and closing the MOS tube Q2, wherein under the normal condition, the MOS tube Q1 is disconnected, the internal resistance is over 10Mohm, and if the voltage of the read V1 is less than 0.1V, the MOS tube Q1 is considered to have short circuit abnormality.

4. And disconnecting the MOS tubes Q1 and Q2, wherein the MOS tubes Q1 and Q2 are disconnected under the normal condition, the internal resistance is over 10Mohm, and if the voltage of the read V1 is less than 0.4V, the MOS tube Q1 is considered to have a short circuit.

The present invention and its embodiments have been described above schematically, and the description is not limited thereto, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching of the present invention, without departing from the inventive spirit of the present invention, the person skilled in the art should also design the similar structural modes and embodiments without creativity to the technical solution, and all shall fall within the protection scope of the present invention.

Claims

1. A self-diagnostic circuit for protecting a MOSFET, comprising: the device comprises a voltage acquisition module and a current excitation module, wherein in the current excitation module, a battery pack BT1 applies excitation current to a protection plate, and the voltage acquisition module is electrically connected with a protection plate AFE; in the current excitation module, the anode of a battery pack BT1 is connected to the S pole of an MOS (metal oxide semiconductor) transistor Q2 through a switch SW1, the D pole of the MOS transistor Q2 is connected to the D pole of the MOS transistor Q1, and the S pole of the MOS transistor Q1 is connected to the cathode of the battery pack BT 1; the G pole of the MOS tube Q2 is connected to the charging control port of the protection plate AFE, and the G pole of the MOS tube Q1 is connected to the discharging control port of the protection plate AFE.

2. A protection board MOSFET self-diagnostic circuit as claimed in claim 1, wherein: a shunt R1 is further arranged between the negative electrode of the battery pack BT1 and the MOS transistor Q1, and the negative electrode of the battery pack BT1 is grounded.

3. A protection board MOSFET self-diagnostic circuit as claimed in claim 2, wherein: the voltage acquisition module comprises an amplifier U1, the positive electrode input end of the amplifier U1 is connected with the S electrode of an MOS tube Q2, and the voltage of the protection plate AFE is detected through the MOS tube Q2; the negative input end of the amplifier U1 is connected with the output end of the amplifier U1, and the output end of the amplifier U1 is connected with the display voltage of the display; the negative power supply end of the amplifier U1 is grounded, and the positive power supply end is connected with the MCU.

4. A protection board MOSFET self-diagnostic circuit as defined in claim 3, wherein: and a current detection module is connected between the MOS tube Q1 and the shunt R1 to detect the current of the shunt R1.

5. The self-diagnostic circuit of a protection board MOSFET of claim 4, wherein: the current detection module comprises an amplifier U2, the positive input end of the amplifier U2 is connected with the S pole of the MOS tube Q1, the negative input end of the amplifier U2 is connected with the output end of the amplifier U2, and the output end is connected with the display; the negative power supply end of the amplifier U2 is grounded, and the positive power supply end is connected with the MCU.

6. A protection board MOSFET self-diagnostic circuit as claimed in claim 5, wherein: and a load RLOAD is connected between the switch SW1 and the MOS tube Q2.

7. A protection board MOSFET self-diagnostic circuit as claimed in claim 6, wherein: and the MCU connected with the amplifier U1 and the amplifier U2 provides 3.3V voltage.