BMS dual protection circuit and protection method

Abstract

The invention provides a BMS dual protection circuit and protection method. The circuit comprises a charging loop and a discharging loop. The charging loop also comprises a primary charging MOS tube Q3, a secondary charging MOS tube Q4 and an isolation MOS tube Q5 which are connected with the power supply end in sequence; the other end of the isolation MOS tube Q5 is connected with a charging C-end; the first protection circuit is connected with the primary charging MOS tube Q3 in parallel; the second protection circuit is connected in parallel with the double charging MOS tube Q4 and the isolation MOS tube Q5; the discharge loop also comprises a first discharge circuit and a second discharge circuit, wherein the first discharge circuit and the second discharge circuit are connected in series between the battery and the output end load. According to the invention, a dual control scheme is utilized, that is, charging and discharging processes are realized through hardware control, and flowing of current is controlled by adopting different MOS tubes and signals during charging and discharging, so that a safe and efficient charging and discharging process is realized.

Description

Technical Field

[0001] The present application belongs to the field of circuit protection technology, and in particular, relates to a BMS dual protection circuit and protection method. Background Art

[0002] As lithium-ion batteries are increasingly used in two-wheeled vehicles, market competition is fierce. It is necessary to meet the regulatory requirements for charging and discharging protection circuits while also requiring a low-cost solution. Therefore, a low-cost BMS protection circuit solution is particularly important for product competition in the market.

[0003] At present, in terms of BMS circuits, there are many circuit solutions that use software solutions to control the charging and discharging MOS tubes by communicating with the front-end chip and MCU to meet the dual protection requirements of regulations. This dual protection software BMS solution is relatively expensive and the standby power consumption is relatively high. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the present application provides a BMS dual protection circuit and protection method, which realizes dual protection of charging and discharging by controlling the charging MOS and the discharging MOS through the hardware front-end IC.

[0005] Specifically, the present application provides a BMS dual protection circuit, the circuit comprising: a charging circuit and a discharging circuit;

[0006] The charging circuit also includes: a single-charge MOS tube Q3, a double-charge MOS tube Q4 and an isolation MOS tube Q5 connected in sequence to the power supply end; the other end of the isolation MOS tube Q5 is connected to the charging C-end; a first protection circuit connected in parallel with the single-charge MOS tube Q3; and a second protection circuit connected in parallel with the double-charge MOS tube Q4 and the isolation MOS tube Q5;

[0007] The discharge circuit further comprises: a primary discharge circuit and a secondary discharge circuit, wherein the primary discharge circuit and the secondary discharge circuit are arranged in series between the battery and the output end load.

[0008] Preferably, the first protection circuit includes: a resistor R33, a resistor R37, a transistor Q1, a diode D11, a resistor R39, a voltage stabilizing diode Z5, and a resistor R45;

[0009] Resistor R39 is used to limit the current and drive a heavy charging MOS tube Q3;

[0010] Resistor R45 is used to prevent the first-stage charging MOS tube Q3 from malfunctioning;

[0011] The voltage stabilizing diode Z5 is used to protect the gate source of a heavy charging MOS tube Q3;

[0012] Transistor Q1 is used to amplify current; resistor R33 is used to amplify circuit input resistance; resistor R37 is used to amplify bias; and diode D11 is used for unidirectional conduction.

[0013] Preferably, the second protection circuit includes: a resistor R34, a resistor R38, a transistor Q2, a diode D12, a resistor R40, a voltage stabilizing diode Z6, a resistor R42, and a resistor R41;

[0014] Resistor R40 is used to limit the current and drive the double charging MOS tube Q4;

[0015] Resistor R41 is used to limit the current and drive the isolation MOS tube Q5;

[0016] Resistor R42 is used to prevent the double charging MOS tube Q4 and the isolation MOS tube Q5 from malfunctioning;

[0017] The voltage stabilizing diode Z6 is used to protect the gate-source of the double-charging MOS tube Q4 and the isolation MOS tube Q5;

[0018] Transistor Q2 is used to amplify current; resistor R34 is used to amplify circuit input resistance; resistor R38 is used to amplify bias; and diode D12 is used for unidirectional conduction.

[0019] Preferably, the charging circuit further includes: a capacitor C31 and a capacitor C34; the capacitor C31 and the capacitor C34 are arranged between the charging C+ and the charging C- for filtering processing.

[0020] Preferably, the charging circuit further includes: a sampling resistor R77 and a sampling resistor R80 for current sampling, the sampling resistor R77 and the sampling resistor R80 are connected in parallel, and one end is connected to a heavy charging MOS tube Q3, and the other end is connected to the negative electrode of the battery.

[0021] Preferably, the first discharge circuit comprises: a MOS transistor Q9, a MOS transistor Q12 and a MOS transistor Q16; and a resistor R60, a resistor R70 and a resistor R78 respectively connected in parallel with the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16;

[0022] The resistor R86 and the resistor R53 are connected in series with the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16; the resistor R53 is used for current limiting driving of the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16; the resistor R86 is used for preventing the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16 from malfunctioning.

[0023] Preferably, the double discharge circuit comprises: a MOS tube Q10, a MOS tube Q13 and a MOS tube Q17; and a resistor R61, a resistor R71 and a resistor R79 respectively connected in parallel with the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17;

[0024] The resistor R89 ​​and the resistor R58 are connected in series with the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17; the resistor R89 ​​is used to prevent the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17 from malfunctioning; the resistor R58 is used to limit the current and drive the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17.

[0025] Preferably, the discharge circuit further includes: a capacitor C60 and a capacitor C66; the capacitor C60 and the capacitor C66 are arranged between the load P+ and the load P- for filtering processing.

[0026] Furthermore, the circuit further includes:

[0027] A protection element F1 connected in series with the charging circuit and the discharging circuit;

[0028] A first control chip U1 connected to the first protection circuit;

[0029] A second control chip U2 connected to the second protection circuit;

[0030] The load P+ and the charging C+ are the same port;

[0031] The load P- and the charging C- are different ports.

[0032] Based on the above circuit, the present application also proposes a BMS dual protection circuit protection method, including:

[0033] When the BMS is in the charging state, the CO1 signal of the first control chip U1 and the CO2 signal of the second control chip U2 are both high level, the CO1 signal controls the first charging MOS tube Q3 to be turned on after the current is amplified by the transistor Q1, and the CO2 signal controls the second charging MOS tube Q4 and the isolation MOS tube Q5 to be turned on after the current is amplified by the transistor Q2, and the charging current flows through the protection element F1, the sampling resistor R77 and the sampling resistor R80, the first charging MOS tube Q3, the second charging MOS tube Q4 and the isolation MOS tube Q5;

[0034] When the BMS is in the discharging state, the first control chip U1 outputs a high-level DO1 signal, and the single-discharging MOS tubes Q9, Q12, and Q16 are turned on. The second control chip U2 outputs a high-level DO2 signal, and the double-discharging MOS tubes Q10, Q13, and Q17 are turned on. The discharge current flows through the protection element F1, the output load, the discharge MOS tubes Q9, Q12, Q16, Q10, Q13, and Q17, the sampling resistors R77, and the sampling resistors R80.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] A BMS dual protection circuit and protection method proposed in the present application utilize a dual control scheme, that is, the charging and discharging processes are realized through hardware control, and different MOS tubes and signals are used to control the flow of current during charging and discharging, thereby realizing a safe and efficient charging and discharging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a circuit diagram of a BMS dual protection circuit in an embodiment of the present application.

[0038] Figure 2 This is a circuit diagram of a charging circuit in one embodiment of the present application.

[0039] Figure 3 1 is a circuit diagram of a discharge circuit in one embodiment of the present application.

[0040] Figure 4 This is a diagram of the first control chip U1 in one embodiment of the present application.

[0041] Figure 5 This is a diagram of the second control chip U2 in one embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] Embodiment 1:

[0044] As attached Figure 1 As shown, the present application provides a BMS dual protection circuit, the circuit comprising: a charging circuit and a discharging circuit;

[0045] As attached Figure 2 As shown, the charging circuit also includes: a single-charge MOS tube Q3, a double-charge MOS tube Q4 and an isolation MOS tube Q5 connected to the power supply end in sequence; the other end of the isolation MOS tube Q5 is connected to the charging C-end; a first protection circuit connected in parallel with the single-charge MOS tube Q3; and a second protection circuit connected in parallel with the double-charge MOS tube Q4 and the isolation MOS tube Q5;

[0046] As attached Figure 3 As shown, the discharge circuit further includes: a primary discharge circuit and a secondary discharge circuit, and the primary discharge circuit and the secondary discharge circuit are arranged in series between the battery and the output end load.

[0047] This application ensures that the current flow and voltage control during the charging process are highly safe and avoids potential risks such as overcharging and overcurrent by linking components such as the single-charge MOS tube Q3, the double-charge MOS tube Q4, and the isolation MOS tube Q5, in combination with the first protection circuit and the second protection circuit. By precisely controlling the single and double charge and discharge MOS tubes, the battery management system can achieve a precise charging and discharging process, optimize the battery's charging and discharging efficiency, and extend the battery life; the circuit design includes multiple levels of protection to prevent damage to the battery or other system components due to abnormal voltage and current fluctuations. The safety and reliability of the battery management system are improved through precise current limiting, voltage stabilization, and unidirectional conduction design.

[0048] Preferably, the first protection circuit includes: a resistor R33, a resistor R37, a transistor Q1, a diode D11, a resistor R39, a voltage stabilizing diode Z5, and a resistor R45;

[0049] Resistor R39 is used to limit the current to drive the first recharge MOS tube Q3; prevent the charging current from being too large, and thus protect the first recharge MOS tube Q3 from being damaged by overcurrent. By controlling the driving current of the MOS tube, it is ensured that it works within a safe range to avoid damage to the MOS tube or system failure caused by excessive current.

[0050] The resistor R45 is used to prevent the first-stage charging MOS tube Q3 from malfunctioning when it is not needed; the MOS tube Q3 may be turned on at an inappropriate time due to voltage fluctuations or other external interferences, and R45 helps to suppress these malfunctions by providing appropriate current paths and load conditions. The present application sets the resistor R45 between the gate and source of the MOS tube Q3 to ensure that the MOS tube will only be turned on under reasonable voltage conditions, preventing incorrect turning on or off due to circuit noise or unstable control signals.

[0051] The voltage stabilizing diode Z5 is used to protect the gate-source of the rechargeable MOS tube Q3; when the voltage stabilizing diode Z5 works in the breakdown region, it will provide a stable voltage protection to ensure that the voltage of the gate-source is always within the safe range. If the voltage exceeds the set voltage stabilizing value, Z5 will be turned on to absorb the excessive voltage and protect Q3 from voltage shock. The excessive voltage of the gate-source may cause damage to the MOS tube Q3. The voltage stabilizing diode Z5 stabilizes the gate-source voltage to prevent the excessive voltage from damaging the MOS tube.

[0052] Transistor Q1 is used to amplify the current; it amplifies the weak control signal, thereby driving the gate of MOS tube Q3 to make it work in an appropriate state. When the control circuit generates a small current signal, transistor Q1 amplifies the signal according to the change of the input signal, so that MOS tube Q3 can be stably turned on or off.

[0053] Resistor R33 is used to amplify the circuit input resistance and properly attenuate or amplify the input signal. It works with transistor Q1 to form a stable operating point at the control signal input end. By setting resistor R33, the current input size can be adjusted to ensure that the subsequent current amplification stage (such as the amplification effect of Q1) can effectively control the MOS tube Q3.

[0054] Resistor R37 (bias resistor) is used to amplify the bias effect; by setting the appropriate bias current, resistor R37 enables transistor Q1 to be in the linear amplification region, thereby ensuring that it can effectively respond to the input signal and accurately drive MOS tube Q3. Without proper bias, Q1 may not provide sufficient amplification, resulting in instability of the entire charging circuit.

[0055] Diode D11 (i.e., unidirectional conduction diode) is used for unidirectional conduction. When the current flows in the expected direction, diode D11 conducts and allows the current to pass; when the current flows in the reverse direction, the diode blocks the current flow, thereby protecting the circuit components (such as transistor Q1 and MOS tube Q3) from damage. As a unidirectional conduction element, diode D11 ensures that the current only flows in the specified direction, thereby preventing the reverse current from damaging the circuit. It also helps to avoid malfunction or system instability caused by reverse current.

[0056] In a preferred embodiment, in order to further improve the protection capability of the circuit, some additional functional modules or improvements may be added to the first protection circuit, such as (but not limited to):

[0057] Current monitoring module: By adding a current sensor or a more complex current detection circuit, it is possible to monitor the current changes in real time and dynamically adjust the protection mechanism according to the actual current situation. For example, when overcurrent is detected, the current is immediately cut off or the protection mechanism is triggered to prevent the MOS tube Q3 from overloading.

[0058] Temperature monitoring function: In order to prevent the MOS tube from being damaged due to excessive temperature, a temperature sensor can be added, combined with a thermistor or temperature switch, to monitor the battery temperature and the operating temperature of the MOS tube in real time. When the temperature exceeds the safety threshold, the temperature control protection mechanism is activated.

[0059] Voltage feedback loop: The protection function of Zener diode Z5 can be further enhanced by adding voltage feedback mechanism into the circuit design to ensure that the gate voltage is always within a safe range and avoid voltage surges that damage the MOS tube.

[0060] Through current limiting, biasing, amplification, voltage stabilization and other measures, the system can effectively avoid overcurrent, overvoltage and other problems, and improve the stability and safety of the charging process. In addition, further functional expansion such as current monitoring, temperature protection and voltage feedback mechanism can better cope with complex working environments and improve the safety and reliability of the BMS system.

[0061] Preferably, the second protection circuit includes: a resistor R34, a resistor R38, a transistor Q2, a diode D12, a resistor R40, a voltage-stabilizing diode Z6, a resistor R42, and a resistor R41.

[0062] Resistor R40, i.e., current limiting resistor, is used to limit the current driving the double-charge MOS tube Q4. Resistor R40 controls the magnitude of the current flowing to Q4 so that it operates within a safe current range. Current limitation is essential for the normal operation of the double-charge MOS tube, especially in high-current charging scenarios, which can effectively prevent the MOS tube from being damaged due to overcurrent.

[0063] Resistor R41, i.e., current limiting resistor, is used to limit the current and drive the isolated MOS tube Q5. Resistor R41 is connected to the gate drive circuit of Q5 to limit the current and ensure that the MOS tube will not be damaged or work abnormally due to excessive current. Similar to R40, R41 ensures that the MOS tube Q5 operates within the appropriate current range to prevent the battery management system from malfunctioning due to overcurrent.

[0064] Resistor R42, i.e., anti-misoperation resistor, is used to prevent misoperation of the double-charging MOS tube Q4 and the isolation MOS tube Q5. By properly limiting the current of the gates of Q4 and Q5, R42 can effectively suppress misoperation caused by voltage fluctuations or external noise, ensuring that the MOS tube works stably according to the predetermined control conditions. Misoperation or shutdown of the MOS tube at an inappropriate time will affect the charging efficiency and may cause damage to the circuit components. The role of R42 is to ensure that the MOS tube only works at the right time through appropriate current paths and voltage adjustments.

[0065] The voltage stabilizing diode Z6 is used to protect the gate-source of the double-charged MOS tube Q4 and the isolated MOS tube Q5. The voltage stabilizing diode Z6 ensures that the gate-source voltage is always kept within a safe range through its voltage stabilizing characteristics. When the gate-source voltage is too high, Z6 starts to conduct and guides the excess voltage to a safe path, thereby protecting the MOS tube from overvoltage damage.

[0066] Transistor Q2 is used to amplify the current and drive the gates of MOS tubes Q4 and Q5 to ensure that they can work according to the control logic of the battery management system; driven by the input signal, Q2 converts it into a sufficiently large current signal to drive the gate switches of Q4 and Q5. Through proper current amplification, Q2 ensures that the MOS tube can respond and control the charging process as expected.

[0067] Input resistor R34 is used to amplify the input resistance of the circuit; resistor R34 adjusts the impedance of the circuit input end to match the input signal, ensuring that transistor Q2 can amplify the signal in the best working state and avoid malfunction caused by excessively high or low input voltage. R34 works with Q2 to ensure the stability and accuracy of the signal during current amplification.

[0068] The bias resistor R38 is used to amplify the bias effect; the resistor R38 sets a suitable current to flow to the base of Q2, ensuring that the transistor can enter the appropriate amplification area and stably respond to the input signal. The appropriate bias current can enable Q2 to effectively amplify the input signal, thereby driving the MOS tubes Q4 and Q5.

[0069] The unidirectional conducting diode D12 is used for unidirectional conduction. When the current flows in the predetermined direction, D12 is turned on to allow the current to pass; when the current flows in the reverse direction, the diode D12 blocks the current to prevent it from flowing in the reverse direction, thus protecting Q2 and the MOS tube from damage.

[0070] The second protection circuit of this circuit ensures the normal operation of multiple MOS tubes (Q4, Q5) during the charging process and prevents problems such as overcurrent, overvoltage and malfunction through carefully designed current limiting, amplification, biasing and protection mechanisms. Combined with components such as voltage regulator diodes, transistors, resistors, etc., the second protection circuit plays a key role in protecting the battery management system. Further expansion and optimization such as temperature monitoring, current feedback and redundant design can effectively improve the stability and reliability of the entire battery management system.

[0071] Preferably, during the charging process, the power supply may generate high-frequency noise, fluctuations or transients. Based on this, the charging circuit described in the present application also includes: capacitor C31 and capacitor C34; the capacitor C31 and capacitor C34 are arranged between charging C+ and charging C- for filtering. By short-circuiting the high-frequency signal, the low-frequency DC signal is allowed to pass, thereby smoothing the voltage output and reducing the impact of power supply noise on battery charging, reducing high-frequency noise and fluctuations in the power supply signal. This filtering helps to stabilize the charging current and improve the stability and efficiency of battery charging. Among them, the capacity of C31 and C34 is generally selected according to the operating frequency and noise requirements of the circuit. Larger capacitors can more effectively smooth low-frequency signals, while smaller capacitors are suitable for filtering high-frequency noise.

[0072] Preferably, the charging circuit also includes: a sampling resistor R77 and a sampling resistor R80 for current sampling, wherein the sampling resistor R77 and the sampling resistor R80 are connected in parallel, and one end is connected to a heavy charging MOS tube Q3, and the other end is connected to the negative electrode of the battery. By sampling the voltage and the known resistance value, the charging current can be accurately calculated. If the current is too large or too small, the battery management system (BMS) can adjust the charging process by adjusting the switching state of the MOS tube to ensure safe charging of the battery.

[0073] Among them, the control of the first recharge MOS tube Q3 is usually adjusted by the BMS through its gate voltage. When the current detected by the current sampling resistor exceeds the predetermined range, the BMS will adjust the gate voltage of the first recharge MOS tube Q3, change the conduction state of the MOS tube, and then adjust the charging current flowing to the battery.

[0074] The switching state of the first-stage charging MOS tube Q3 is closely related to the feedback of the current sampling resistor, ensuring that the battery is always charged within a safe charging current range.

[0075] Preferably, as attached Figure 3 As shown, the first discharge circuit includes: a MOS tube Q9, a MOS tube Q12 and a MOS tube Q16; and a resistor R60, a resistor R70 and a resistor R78 respectively connected in parallel with the MOS tube Q9, the MOS tube Q12 and the MOS tube Q16;

[0076] The resistor R86 and the resistor R53 are connected in series with the MOS tube Q9, the MOS tube Q12 and the MOS tube Q16; the resistor R53 is used to limit the current and drive the MOS tube Q9, the MOS tube Q12 and the MOS tube Q16; if the gate current is too large, it may cause overshoot or unstable operation of the MOS tube, and even damage the gate drive circuit. R53 is connected in series in the gate drive path to limit the current flowing through the MOS tube gate, thereby ensuring that the MOS tube is turned on and off smoothly. Usually, the resistance value will be selected between several hundred ohms and several thousand ohms to ensure the stable operation of the MOS tube under the appropriate drive current, which is not limited here.

[0077] During the operation of the circuit, due to noise, transient voltage changes or other interference, the MOS tube may be subjected to an unexpected activation signal, causing it to malfunction, thereby causing circuit instability or failure. The present application adds a resistor R86 to reduce the possibility of such malfunction by limiting unnecessary current or stabilizing voltage. Therefore, the resistor R86 is used to prevent MOS tube Q9, MOS tube Q12 and MOS tube Q16 from malfunctioning.

[0078] Preferably, the double discharge circuit comprises: a MOS tube Q10, a MOS tube Q13 and a MOS tube Q17; wherein:

[0079] R61 (in parallel with Q10): The role of resistor R61 may be to limit the current passing through Q10 to prevent excessive current from damaging the MOS tube. It may also play a role in balancing current distribution to ensure uniform distribution of discharge current.

[0080] R71 (in parallel with Q13): Similarly, R71 limits the current of Q13 and helps to distribute the current reasonably among multiple parallel MOS tubes. If Q13 is overloaded, R71 can provide a current shunt path to protect Q13.

[0081] R79 (in parallel with Q17): The function of R79 is similar to that of R61 and R71. It ensures that the current of Q17 is not too large when it is working, and at the same time provides a certain protection for Q17.

[0082] The double discharge circuit is usually used in energy storage systems, such as battery or capacitor discharge management. MOS tubes Q10, Q13 and Q17 are used as switch elements to start or stop the discharge process according to the control signal. The resistors (R61, R71, R79) connected in parallel with them ensure that there will not be too much current passing through a single path during different discharge processes, thereby avoiding damage to circuit components.

[0083] The resistor R89 ​​and the resistor R58 are connected in series with the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17; the resistor R89 ​​is used to prevent the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17 from malfunctioning; the resistor R58 is used to limit the current and drive the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17.

[0084] Preferably, the discharge circuit further includes: a capacitor C60 and a capacitor C66; the capacitor C60 and the capacitor C66 are arranged between the load P+ and the load P- for filtering processing.

[0085] Furthermore, the circuit further includes:

[0086] A protection element F1 connected in series with the charging circuit and the discharging circuit;

[0087] The first control chip U1 connected to the first protection circuit is as shown in the attached Figure 4 As shown;

[0088] The second control chip U2 connected to the second protection circuit is as shown in the attached Figure 5 As shown;

[0089] The load P+ and the charging C+ are the same port;

[0090] The load P- and the charging C- are different ports.

[0091] Embodiment 2: The present application also proposes a BMS dual protection circuit protection method, comprising:

[0092] When the BMS is in the charging state, the CO1 signal of the first control chip U1 and the CO2 signal of the second control chip U2 are both high level, the CO1 signal controls the first charging MOS tube Q3 to be turned on after the current is amplified by the transistor Q1, and the CO2 signal controls the second charging MOS tube Q4 and the isolation MOS tube Q5 to be turned on after the current is amplified by the transistor Q2, and the charging current flows through the protection element F1, the sampling resistor R77 and the sampling resistor R80, the first charging MOS tube Q3, the second charging MOS tube Q4 and the isolation MOS tube Q5;

[0093] When the BMS is in the discharging state, the first control chip U1 outputs a high-level DO1 signal, and the single-discharging MOS tubes Q9, Q12, and Q16 are turned on. The second control chip U2 outputs a high-level DO2 signal, and the double-discharging MOS tubes Q10, Q13, and Q17 are turned on. The discharge current flows through the protection element F1, the output load, the discharge MOS tubes Q9, Q12, Q16, Q10, Q13, and Q17, the sampling resistors R77, and the sampling resistors R80.

[0094] In summary, during charging, the control chips U1 and U2 control the conduction of the MOS tubes through high-level signals to ensure that the charging current passes through the first and second charging MOS tubes and the isolation MOS tube. During discharging, U1 and U2 control the conduction of the first and second discharging MOS tubes through DO1 and DO2 signals respectively, so that the discharge current can flow to the load, and the current is monitored through the sampling resistor. The protection element F1 plays a protective role in both states to ensure the safety of the battery management system.

[0095] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0096] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0097] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0098] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0099] Although the description of the present application is carried out in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes based on the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. A BMS dual protection circuit, the circuit comprising: Charging circuit and discharging circuit; characterized in that the charging circuit also includes: a single-charge MOS tube Q3, a double-charge MOS tube Q4 and an isolation MOS tube Q5 connected to the power supply end in sequence; the other end of the isolation MOS tube Q5 is connected to the charging C-end; a first protection circuit connected in parallel with the single-charge MOS tube Q3; and a second protection circuit connected in parallel with the double-charge MOS tube Q4 and the isolation MOS tube Q5; The discharge circuit further comprises: a primary discharge circuit and a secondary discharge circuit, wherein the primary discharge circuit and the secondary discharge circuit are arranged in series between the battery and the output end load.

2. A BMS dual protection circuit as claimed in claim 1, characterized in that: The first protection circuit includes: a resistor R33, a resistor R37, a transistor Q1, a diode D11, a resistor R39, a voltage stabilizing diode Z5, and a resistor R45; Resistor R39 is used to limit the current and drive a heavy charging MOS tube Q3; Resistor R45 is used to prevent the first-stage charging MOS tube Q3 from malfunctioning; The voltage stabilizing diode Z5 is used to protect the gate source of a heavy charging MOS tube Q3; Transistor Q1 is used to amplify current; resistor R33 is used to amplify circuit input resistance; resistor R37 is used to amplify bias; and diode D11 is used for unidirectional conduction.

3. A BMS dual protection circuit according to claim 2, characterized in that: The second protection circuit includes: a resistor R34, a resistor R38, a transistor Q2, a diode D12, a resistor R40, a voltage stabilizing diode Z6, a resistor R42, and a resistor R41; Resistor R40 is used to limit the current and drive the double charging MOS tube Q4; Resistor R41 is used to limit the current and drive the isolation MOS tube Q5; Resistor R42 is used to prevent the double charging MOS tube Q4 and the isolation MOS tube Q5 from malfunctioning; The voltage stabilizing diode Z6 is used to protect the gate-source of the double-charging MOS tube Q4 and the isolation MOS tube Q5; Transistor Q2 is used to amplify current; resistor R34 is used to amplify circuit input resistance; resistor R38 is used to amplify bias; and diode D12 is used for unidirectional conduction.

4. A BMS dual protection circuit according to claim 1, characterized in that: The charging circuit further includes: a capacitor C31 and a capacitor C34; the capacitor C31 and the capacitor C34 are arranged between the charging C+ and the charging C- for filtering.

5. A BMS dual protection circuit according to claim 1, characterized in that: The charging circuit also includes: a sampling resistor R77 and a sampling resistor R80 for current sampling. The sampling resistor R77 and the sampling resistor R80 are connected in parallel, and one end of the sampling resistor R77 and the sampling resistor R80 are connected to a heavy charging MOS tube Q3, and the other end is connected to the negative electrode of the battery.

6. A BMS dual protection circuit according to claim 1, characterized in that: The first discharge circuit includes: a MOS tube Q9, a MOS tube Q12 and a MOS tube Q16; and a resistor R60, a resistor R70 and a resistor R78 respectively connected in parallel with the MOS tube Q9, the MOS tube Q12 and the MOS tube Q16; The resistor R86 and the resistor R53 are connected in series with the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16; the resistor R53 is used for current limiting driving of the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16; the resistor R86 is used for preventing the MOS transistor Q9, the MOS transistor Q12 and the MOS transistor Q16 from malfunctioning.

7. A BMS dual protection circuit according to claim 6, characterized in that: The double discharge circuit includes: a MOS tube Q10, a MOS tube Q13 and a MOS tube Q17; and a resistor R61, a resistor R71 and a resistor R79 respectively connected in parallel with the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17; The resistor R89 ​​and the resistor R58 are connected in series with the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17; the resistor R89 ​​is used to prevent the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17 from malfunctioning; the resistor R58 is used to limit the current and drive the MOS tube Q10, the MOS tube Q13 and the MOS tube Q17.

8. A BMS dual protection circuit according to claim 1, characterized in that: The discharge circuit further includes: a capacitor C60 and a capacitor C66; the capacitor C60 and the capacitor C66 are arranged between the load P+ and the load P- for filtering.

9. A BMS dual protection circuit according to claim 1, characterized in that: The circuit further comprises: A protection element F1 connected in series with the charging circuit and the discharging circuit; A first control chip U1 connected to the first protection circuit; A second control chip U2 connected to the second protection circuit; The load P+ and the charging C+ are the same port; The load P- and the charging C- are different ports.

10. A protection method for a BMS dual protection circuit according to claims 1-9, characterized in that: include: When the BMS is in the charging state, the CO1 signal of the first control chip U1 and the CO2 signal of the second control chip U2 are both high level, the CO1 signal controls the first charging MOS tube Q3 to be turned on after the current is amplified by the transistor Q1, and the CO2 signal controls the second charging MOS tube Q4 and the isolation MOS tube Q5 to be turned on after the current is amplified by the transistor Q2, and the charging current flows through the protection element F1, the sampling resistor R77 and the sampling resistor R80, the first charging MOS tube Q3, the second charging MOS tube Q4 and the isolation MOS tube Q5; When the BMS is in the discharging state, the first control chip U1 outputs a high-level DO1 signal, and the single-discharging MOS tubes Q9, Q12, and Q16 are turned on. The second control chip U2 outputs a high-level DO2 signal, and the double-discharging MOS tubes Q10, Q13, and Q17 are turned on. The discharge current flows through the protection element F1, the output load, the discharge MOS tubes Q9, Q12, Q16, Q10, Q13, and Q17, the sampling resistors R77, and the sampling resistors R80.

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