Circuit for protecting MOS tube during short circuit of battery BMS

Abstract

The utility model relates to the technical improvement of a battery BMS (Battery Management System) protection board, in particular to a circuit for protecting an MOS (Metal Oxide Semiconductor) tube when a battery BMS is short-circuited, which is used for effectively protecting the MOS tube by additionally arranging a protection structure. Comprising a power supply, an MCU module MOS tube Q1 and a short-circuit line L1, a BATT + and a BATT-of the power supply are electrically connected with the MCU module, a grid electrode of the MOS tube Q1 is electrically connected with the MCU module, a source electrode of the MOS tube Q1 is electrically connected with a power supply BATT-, an output of the power supply BATT + is connected with a drain electrode of the MOS tube Q1 through the short-circuit line L1, a positive electrode of the diode D1 is connected with the drain electrode of the MOS tube Q1, a negative electrode of the diode D1 is connected between the BATT + of the power supply and the short-circuit line L1, and a negative electrode of the diode D1 is connected with a negative electrode of the MOS tube Q1. The positive electrode of the diode is connected between the drain electrode of the MOS tube Q1 and the short-circuit line L1.

Description

Technical Field

[0001] This utility model relates to a technical improvement of a battery BMS protection board, specifically a circuit for protecting the MOSFET when the battery BMS is short-circuited. Background Technology

[0002] The existing battery BMS control board block diagram is as follows: Figure 1 As shown, the block diagram for outputting positive and negative short circuits is as follows: Figure 2 As shown,

[0003] Because the battery has a lot of energy, when a short circuit occurs at the output, the current flowing through the short circuit line L1 is very large. Even if L1 has only a small inductance, it will generate a large induced electromotive force, resulting in charging and discharging, which will generate a very high voltage. This high voltage will be applied to the MOSFET Q1, causing Q1 to withstand a very large voltage, exceeding the withstand voltage of the MOSFET Q1, and even damaging the MOSFET Q1.

[0004] How to protect the MOSFET in the event of a short circuit on an existing battery BMS control board is a technical problem that needs to be solved. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the existing defects and provide a circuit for protecting the MOSFET when the battery BMS is short-circuited. By adding a protection structure, the MOSFET is effectively protected.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a circuit for protecting the MOSFET when the battery BMS is short-circuited, including a power supply, an MCU module MOSFET Q1, and a shorting line L1. The BATT+ and BATT- of the power supply are electrically connected to the MCU module, the gate of the MOSFET Q1 is electrically connected to the MCU module, the source of the MOSFET Q1 is electrically connected to the power supply BATT-, the output of the power supply BATT+ is connected to the drain of the MOSFET Q1 through the shorting line L1, and a diode D1 is also included. The anode of the diode D1 is connected to the drain of the MOSFET Q1, the cathode of the diode is connected between the power supply BATT+ and the shorting line L1, and the anode of the diode is connected between the drain of the MOSFET Q1 and the shorting line L1.

[0007] Preferably, the forward voltage of the diode D1 is higher than the power supply voltage.

[0008] The beneficial effects of this utility model are as follows: The circuit for protecting the MOSFET when the battery BMS is short-circuited is designed with a protective structure, namely diode D1, between the MOSFET and the short circuit line, and the MOSFET is effectively protected by controlling the conduction voltage of diode D1. Attached Figure Description

[0009] Figure 1 Block diagram of existing battery BMS control board;

[0010] Figure 2 Block diagram of the existing battery BMS control board outputting positive and negative short circuits;

[0011] Figure 3 This is a block diagram of the battery BMS control board of the present invention;

[0012] Figure 4 This is a block diagram of the battery BMS control board outputting positive and negative short circuits according to the present invention. Detailed Implementation

[0013] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0014] like Figure 3 As shown, the circuit for protecting the MOSFET during a short circuit in a battery BMS of this invention includes a power supply, an MCU module, a MOSFET Q1, and a shorting line L1. The power supply's BATT+ and BATT- are electrically connected to the MCU module, the gate of the MOSFET Q1 is electrically connected to the MCU module, the source of the MOSFET Q1 is electrically connected to the power supply's BATT-, and the output of the power supply's BATT+ is connected to the drain of the MOSFET Q1 through the shorting line L1. The invention is characterized by further including a diode D1. The anode of the diode D1 is connected to the drain of the MOSFET Q1, the cathode of the diode is connected between the power supply's BATT+ and the shorting line L1, and the anode of the diode is connected between the drain of the MOSFET Q1 and the shorting line L1. The forward voltage of the diode D1 is higher than the power supply voltage.

[0015] like Figure 4 As shown, since the battery has a lot of energy, when the output is short-circuited, the current flowing through the short-circuit line L1 is very large. Even if L1 has only a small inductance, it will generate a large induced electromotive force, resulting in charging and discharging, which will generate a very high voltage. This high voltage will be applied to the MOSFET Q1 through the short-circuit MOSFET.

[0016] When the voltage is higher than the BATT+ voltage, diode D1 will conduct, returning the drain voltage of Q1 to L1. This absorbs some of the energy of the short circuit L1, which is equivalent to adding an absorption, allowing the MOSFET Q1 to withstand much less energy. The current direction is L1→D1→L1.

[0017] Taking a 20-cell, 72V ternary lithium battery (20AH) as an example for short-circuit testing: During positive and negative short-circuit testing, the drain voltage of MOSFET Q1 will reach 135V. Increasing the voltage by... Figure 4After diode D1 is shown, the voltage drops to 110V during short-circuit testing; this greatly reduces the drain voltage of the MOSFET and provides significant protection for the MOSFET.

[0018] The above are preferred embodiments of this utility model. Those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above. Any obvious improvements, substitutions or modifications made by those skilled in the art based on this utility model shall fall within the protection scope of this utility model.

Claims

1. A circuit for protecting a MOSFET during a short circuit in a battery BMS, comprising a power supply, an MCU module MOSFET Q1, and a shorting line L1, wherein the power supply's BATT+ and BATT- are electrically connected to the MCU module, the gate of the MOSFET Q1 is electrically connected to the MCU module, the source of the MOSFET Q1 is electrically connected to the power supply's BATT-, and the output of the power supply's BATT+ is connected to the drain of the MOSFET Q1 through the shorting line L1, characterized in that... It also includes diode D1, whose anode is connected to the drain of MOSFET Q1, whose cathode is connected between the power supply BATT+ and short circuit L1, and whose anode is connected between the drain of MOSFET Q1 and short circuit L1.

2. The circuit for protecting the MOSFET during a short circuit in the battery BMS as described in claim 1, characterized in that, The forward voltage of diode D1 is higher than the power supply voltage.

Images