Protection circuit of MOS tube for BMS
By introducing diode D1 into the MOS tube protection circuit of the battery BMS, the high voltage of the drain of the MOS tube Q1 is returned to the problem of damage caused by excessive voltage in the case of short circuit, and achieving higher durability.
Patent Information
- Application Number
- CN202421736757.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-22
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-07-22
AI Technical Summary
In the application of battery BMS, MOS tubes are prone to withstand excessive voltages in short circuit situations, resulting in damage. No effective solution has been proposed in the prior art.
A protection circuit for BMS MOS tube is designed. By adding diode D1 between the drain of MOS tube Q1 and the battery BATT+, and connecting the positive electrode of D1 to the drain of MOS tube Q1 and the inductor L1 of the short-circuit line, the diode D1 is turned on when the voltage is higher than BATT+, and the voltage of the drain of MOS tube Q1 is returned to the inductor L1 of the short-circuit line, reducing the voltage of the drain of MOS tube Q1.
It effectively reduces the voltage of the drain of MOS tube Q1, prevents the MOS tube Q1 from being damaged due to excessive voltage, and significantly improves the durability of the MOS tube.
Smart Images
Figure CN222884347U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of battery BMS protection boards, in particular to a protection circuit for a MOS tube used in a BMS. Background Art
[0002] BMS (Battery Management System) is a system used to manage and monitor battery packs to ensure that batteries work in a safe, reliable and efficient state. BMS is widely used in electric vehicles, energy storage systems, consumer electronics and other fields.
[0003] MOS tube, the full name of metal oxide semiconductor field effect transistor, is a field effect transistor widely used in electronic circuits. It has become one of the core components of modern electronic devices with its advantages of high efficiency, low power consumption and fast switching speed. BMS usually uses MOS tubes to protect batteries from overcharge, over discharge, over current and short circuit.
[0004] like Figure 2 As shown, in specific applications, 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 the short-circuit line L1 has only a small inductance, it will bring a large induced electromotive force, resulting in charging and discharging, thereby generating a very high voltage. This high voltage will be added to the MOS tube Q1 through the body diode of the MOS tube Q2, causing Q1 to withstand a large voltage, exceeding the withstand voltage of the MOS tube Q1, and even damaging the MOS tube Q1.
[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Utility Model Content
[0006] In view of the problems in the related art, the utility model proposes a protection circuit for a MOS tube for a BMS to overcome the above technical problems existing in the existing related art.
[0007] To this end, the specific technical solutions adopted by the utility model are as follows:
[0008] A protection circuit for a MOS tube for a BMS includes a battery E1, a battery E2, a battery E3, a chip U1, a resistor R1, a diode D1, a MOS tube Q1, a MOS tube Q2 and an inductor L1 of a short circuit;
[0009] The battery E1, the battery E2 and the battery E3 are connected in sequence, one end of the battery E1 is respectively connected to the first pin of the chip U1, one end of the diode D1 and one end of the inductor L1 of the short-circuit line, and the other end of the inductor L1 of the short-circuit line is connected to the source of the MOS tube Q2;
[0010] The other end of the battery E3 is connected to the second pin of the chip U1 and one end of the resistor R1 respectively, and one end of the resistor R1 is connected to the third pin of the chip U1 and the source of the MOS tube Q1 respectively;
[0011] The fourth pin of the chip U1 is connected to the gate of the MOS transistor Q1, the fifth pin of the chip U1 is connected to the gate of the MOS transistor Q2, and the other end of the diode D1 is connected to the drain of the MOS transistor Q1 and the drain of the MOS transistor Q2 respectively.
[0012] Furthermore, when the inductor L1 of the short-circuit generates a high voltage, the high voltage is applied to the MOS tube Q1 through the body diode in the MOS tube Q2.
[0013] Furthermore, when the voltage is higher than the positive electrode voltage of the battery, the diode D1 may be turned on to return the voltage of the drain of the MOS tube Q1 to the inductor L1 of the short-circuit line.
[0014] Furthermore, the current flows back to the inductor L1 of the short-circuit line through the diode D1 after passing through the inductor L1 of the short-circuit line.
[0015] The beneficial effects of the utility model are:
[0016] 1. The utility model sets a diode D1 so that when the voltage is higher than BATT+, the diode D1 will be turned on, and then the voltage of the drain of the MOS tube Q1 will flow back to the inductor L1 of the short-circuit line, which greatly reduces the voltage of the drain of the MOS tube Q1.
[0017] 2. When the battery generates a large energy output and a short circuit occurs, generating a very high voltage, the utility model adds the high voltage to the MOS tube Q1 through the body diode of the MOS tube Q2, thereby preventing the MOS tube Q1 from being subjected to a large voltage that exceeds the withstand voltage of the MOS tube Q1 and causing damage to the MOS tube Q1. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0019] Figure 1 This is a schematic diagram of a protection circuit for a MOS tube for BMS according to an embodiment of the utility model;
[0020] Figure 2 This is the sub-block diagram of the existing battery BMS control board. DETAILED DESCRIPTION
[0021] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementation methods and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.
[0022] According to an embodiment of the utility model, a protection circuit for a MOS tube for a BMS is provided.
[0023] The present invention is now further described in conjunction with the accompanying drawings and specific implementation methods. Figure 1 As shown, the protection circuit of the MOS tube for BMS according to the embodiment of the utility model includes a battery E1, a battery E2, a battery E3, a chip U1, a resistor R1, a diode D1, a MOS tube Q1, a MOS tube Q2 and an inductor L1 of a short circuit line;
[0024] The battery E1, the battery E2 and the battery E3 are connected in sequence, one end of the battery E1 is respectively connected to the first pin of the chip U1, one end of the diode D1 and one end of the inductor L1 of the short-circuit line, and the other end of the inductor L1 of the short-circuit line is connected to the source (S) of the MOS tube Q2;
[0025] The other end of the battery E3 is connected to the second pin of the chip U1 and one end of the resistor R1 respectively, and one end of the resistor R1 is connected to the third pin of the chip U1 and the source of the MOS tube Q1 respectively;
[0026] The fourth pin of the chip U1 is connected to the gate (G) of the MOS transistor Q1, the fifth pin of the chip U1 is connected to the gate of the MOS transistor Q2, and the other end of the diode D1 is connected to the drain (D) of the MOS transistor Q1 and the drain (D) of the MOS transistor Q2.
[0027] In this embodiment, when the short-circuit line L1 generates a high voltage, the high voltage is applied to the MOS transistor Q1 through the body diode in the MOS transistor Q2.
[0028] In this embodiment, when the voltage is higher than the positive electrode voltage of the battery, the diode D1 may be turned on to return the voltage at the drain of the MOS tube Q1 to the inductor L1 of the short-circuit line.
[0029] In this embodiment, the current flows through the inductor L1 of the short-circuit line and then flows back to the inductor L1 of the short-circuit line through the diode D1 .
[0030] It needs to be explained that Figure 1As shown, a diode D1 is added between the drain of the MOS tube Q1 and the battery BATT+, and the anode of D1 is connected to the drain of the MOS tube Q1, and the anode of the diode D1 is connected to the MOS tube Q1 BATT+ and the inductor L1 of the short-circuit.
[0031] In the prior art, since the battery has a large amount of energy, when the output is short-circuited, the current flowing through the inductor L1 of the short-circuit line is very large. Even if the inductor L1 of the short-circuit line has only a small inductance, a large induced electromotive force will be generated, resulting in charging and discharging, thereby generating a very high voltage. At this time, the high voltage will be added to the MOS tube Q1 through the body diode of the MOS tube Q2.
[0032] When the voltage is higher than BATT+, the diode D1 will be turned on, and the voltage at the drain of the MOS tube Q1 will flow back to the inductor L1 of the short-circuit line. At this time, the current direction is: the inductor L1 of the short-circuit line to the diode D1 and finally back to the inductor L1 of the short-circuit line.
[0033] In order to facilitate understanding of the above technical solution of the present invention, the working principle or operation method of the present invention in the actual process is described in detail below.
[0034] In practical application, take a 20-series 72V ternary lithium battery 20AH battery short circuit test as an example:
[0035] When the output positive and negative short-circuit test is performed, the drain voltage of the MOS tube Q1 will reach 125V. After adding the diode D1, it is reduced to 100V during the short-circuit test, which greatly reduces the drain voltage of the MOS tube Q1, and the effect is obvious.
[0036] In summary, with the aid of the above technical solution of the utility model, the utility model sets a diode D1 so that when the voltage is higher than the voltage of BATT+, the diode D1 will be turned on, and then the voltage of the drain of the MOS tube Q1 will flow back to the inductor L1 of the short-circuit line, greatly reducing the voltage of the drain of the MOS tube Q1. When the battery generates a large energy output and a short circuit occurs, generating a very high voltage, the utility model adds the high voltage to the MOS tube Q1 through the body diode of the MOS tube Q2, thereby preventing the MOS tube Q1 from being subjected to a large voltage that exceeds the withstand voltage of the MOS tube Q1 and causing damage to the MOS tube Q1.
[0037] In the present utility model, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the utility model according to the specific circumstances.
[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A protection circuit for a MOS tube for BMS, characterized in that: It includes battery E1, battery E2, battery E3, chip U1, resistor R1, diode D1, MOS tube Q1, MOS tube Q2 and short-circuit inductor L1; The battery E1, the battery E2 and the battery E3 are connected in sequence, one end of the battery E1 is respectively connected to the first pin of the chip U1, one end of the diode D1 and one end of the inductor L1 of the short-circuit line, and the other end of the inductor L1 of the short-circuit line is connected to the source of the MOS tube Q2; The other end of the battery E3 is connected to the second pin of the chip U1 and one end of the resistor R1 respectively, and one end of the resistor R1 is connected to the third pin of the chip U1 and the source of the MOS tube Q1 respectively; The fourth pin of the chip U1 is connected to the gate of the MOS transistor Q1, the fifth pin of the chip U1 is connected to the gate of the MOS transistor Q2, and the other end of the diode D1 is connected to the drain of the MOS transistor Q1 and the drain of the MOS transistor Q2 respectively.
2. A protection circuit for a MOS tube for BMS according to claim 1, characterized in that: When the inductor L1 of the short-circuit line generates a high voltage, the high voltage is applied to the MOS transistor Q1 through the body diode in the MOS transistor Q2.
3. The protection circuit of a MOS tube for BMS according to claim 1, characterized in that: When the voltage is higher than the positive electrode voltage of the battery, the diode D1 may be turned on to return the voltage at the drain of the MOS tube Q1 to the inductor L1 of the short-circuit line.
4. The protection circuit of a MOS tube for BMS according to claim 1, characterized in that: The current flows through the inductor L1 of the short-circuit line and then flows back to the inductor L1 of the short-circuit line through the diode D1.