A fast-driven battery management system and its control method

Abstract

The present invention belongs to the technical field of battery management systems, and discloses a battery management system with fast driving, which includes a main control module, an analog front-end module, and a fast driving circuit. The fast driving circuit includes an energy storage element, a driving switch, a conduction unit, a turn-off unit, and a charge-discharge MOS transistor. When controlling the charge-discharge MOS transistor to conduct, the main control module controls the analog front-end module to charge the energy storage element, and controls the driving switch to control the conduction unit to charge the junction capacitance of the charge-discharge MOS transistor with the energy storage element, so as to achieve fast conduction of the charge-discharge MOS transistor; when controlling the charge-discharge MOS transistor to turn off, the main control module controls the driving switch to control the turn-off unit to connect the gate and source of the charge-discharge MOS transistor, so that the junction capacitance discharges, and achieves fast turn-off of the charge-discharge MOS transistor. Through the setting of the analog front-end module and the fast driving circuit, the present invention realizes fast switching of the charge-discharge MOS transistor, and solves the problem of weak direct driving ability of the BMS chip.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery management systems, and particularly relates to a fast-driven battery management system and its control method. Background Art

[0002] With the rapid development of the new energy market and technology, the application of energy storage batteries has become increasingly widespread. In large-scale energy storage systems, the battery system needs to support large charging and discharging currents, and multiple MOSFETs need to be connected in parallel to control the input and output of the battery system to meet the large current demand. However, as the number of parallel MOSFETs increases, their junction capacitance also increases, thus requiring a higher driving current to achieve the fast switching of MOSFETs and ensure their normal operation under large current conditions.

[0003] However, in the prior art, common BMS (battery management system) standard chips are directly connected to and control multiple MOSFETs, and the driving ability of the chip output is limited and it is difficult to provide sufficient driving current. When driving multiple MOSFETs, the switching speed will slow down, resulting in possible damage to the MOSFETs during the switching process, thereby posing a potential risk to the safety of the battery system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the driving ability of the battery management system for charging and discharging MOSFETs is insufficient, resulting in a slowdown or even damage to the switching speed of MOSFETs, thereby providing a fast-driven battery management system and its control method.

[0005] A fast-driven battery management system includes a main control module, an analog front-end module, and a fast driving circuit;

[0006] The fast driving circuit includes a charging switch module and a discharging switch module;

[0007] The charging switch module includes a first energy storage element, a first switch, a first conducting unit, a first turning-off unit, and a charging MOS transistor; the first switch is used to drive the switches of the first conducting unit and the first turning-off unit; the first conducting unit connects the first energy storage element to the gate of the charging MOS transistor; the first turning-off unit connects the gate and the source of the charging MOS transistor;

[0008] The discharging switch module includes a second energy storage element, a second switch, a second conducting unit, a second turning-off unit, and a discharging MOS transistor; the second switch is used to drive the switches of the second conducting unit and the second turning-off unit; the second conducting unit connects the second energy storage element to the gate of the discharging MOS transistor; the second turning-off unit (connects the gate and the source of the discharging MOS transistor;

[0009] The charging switch and the discharging switch are connected in series at the output end of the battery;

[0010] The analog front-end module is used to collect data of the battery, including a first charging port and a second charging port, which are respectively connected to the first energy storage element and the second energy storage element;

[0011] The main control module is communicatively connected to the analog front-end module, including a charging control port and a discharging control port, which are respectively connected to the control ends of the first switch and the second switch.

[0012] Further, the first energy storage element and the second energy storage element are energy storage capacitors.

[0013] Further, the first switch and the second switch include small-signal N-channel MOSFETs.

[0014] Further, the first conduction unit and the second conduction unit include small-signal P-channel MOSFETs.

[0015] Further, the charging MOSFET and the discharging MOSFET are N-channel MOSFETs.

[0016] Further, the first turn-off unit includes a first control switch tube and a first drive switch tube; the control end of the first control switch tube is connected to the output end of the first drive switch tube, the output end of the first control switch tube is connected to the control end of the first drive switch tube, and the output end of the first drive switch tube is connected to the gate and source of the discharging MOSFET;

[0017] The second turn-off unit includes a second control switch tube and a second drive switch tube. The control end of the second control switch tube is connected to the output end of the second drive switch tube, the output end of the second control switch tube is connected to the control end of the second drive switch tube, and the output end of the second drive switch tube is connected to the gate and source of the charging MOSFET.

[0018] Further, the first control switch tube and the second control switch tube are small-signal N-channel depletion-mode MOSFETs; the first drive switch tube and the second drive switch tube are small-signal PNP bipolar transistors.

[0019] A control method for a fast-driving battery management system, the battery management system being as described above, the method comprising:

[0020] When driving the charging MOS transistor to conduct, the main control module controls the first charging port of the analog front-end module to start charging, starts timing the charging time of the first energy storage element, and when the charging time reaches the preset time, controls the first charging port of the analog front-end module to stop charging, and controls the first switch to drive the first conducting unit to conduct;

[0021] When driving the discharging MOS transistor to conduct, the main control module controls the second charging port of the analog front-end module to start charging, starts timing the charging time of the second energy storage element, and when the charging time reaches the preset time, controls the second charging port of the analog front-end module to stop charging, and controls the second switch to drive the second conducting unit to conduct.

[0022] Further, the first energy storage element and the second energy storage element are energy storage capacitors, and the preset time satisfies:

[0023] t > 3RC;

[0024] where t is the preset time, R is the corresponding output impedance of the analog front-end module, and C is the capacitance value of the energy storage capacitor.

[0025] Further, the first energy storage element and the second energy storage element are energy storage capacitors. In the charging switch module and the discharging switch module, the capacitance value C of the energy storage capacitor satisfies:

[0026] C > 10 * Cj * (Vgs + Vbat) / Vgs;

[0027] where Vbat is the maximum operating voltage of the battery;

[0028] In the charging switch module, Cj is the junction capacitance of the charging MOS transistor, and Vgs is the driving voltage of the charging MOS transistor;

[0029] In the discharging switch module, Cj is the junction capacitance of the discharging MOS transistor, and Vgs is the driving voltage of the discharging MOS transistor.

[0030] Beneficial effects: The present invention discloses a battery management system with fast driving, which includes a main control module, an analog front-end module, and a fast driving circuit. The fast driving circuit includes an energy storage element, a driving switch, a conduction unit, a turn-off unit, and a charge and discharge MOS transistor. When controlling the charge and discharge MOS transistor to conduct, the main control module controls the analog front-end module to charge the energy storage element, and controls the driving switch to control the conduction unit to charge the junction capacitance of the charge and discharge MOS transistor with the energy storage element, realizing the fast conduction of the charge and discharge MOS transistor; when controlling the charge and discharge MOS transistor to turn off, the main control module controls the driving switch to control the turn-off unit to connect the gate and source of the charge and discharge MOS transistor, discharging the junction capacitance, realizing the fast turn-off of the charge and discharge MOS transistor. Through the setting of the analog front-end module and the fast driving circuit, the present invention realizes the fast switching of the charge and discharge MOS transistor, and solves the problem of weak direct driving ability of the BMS chip. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 is the circuit schematic diagram of the present invention;

[0033] Figure 2 is the schematic diagram of the connection structure of the main control module and the analog front-end module of the present invention.

[0034] Description of the reference numerals: B1, battery; U1, main control module; U2, analog front-end module; C1, first energy storage element; C2, second energy storage element; Q10, charging MOS transistor; Q11, first switch; Q12, first conduction unit; Q13, first control switch transistor; Q14, first driving switch transistor; Q20, discharging MOS transistor; Q21, second switch; Q22, second conduction unit; Q23, second control switch transistor; Q24, second driving switch transistor; R11, first input resistor; R12, first voltage dividing resistor; R13, second voltage dividing resistor; R21, second input resistor; R22, third voltage dividing resistor; R23, fourth voltage dividing resistor; CRL1, charging control port; CRL2, discharging control port; CHG1, first charging port; CHG2, second charging port; OUT+, positive output terminal; OUT-, negative output terminal. Detailed Embodiments

[0035] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0036] In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0037] In the present application, unless otherwise clearly defined and limited, terms such as "installed", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0038] Embodiment 1:

[0039] Referring to Figure 1 and Figure 2 as shown, this embodiment provides a battery management system with fast driving, including a main control module U1, an analog front-end module U2, and a fast driving circuit; the fast driving circuit includes a charging switch module and a discharging switch module;

[0040] The charging switch module includes a first energy storage element C1, a first switch Q11, a first conduction unit Q12, a first turn-off unit, and a charging MOS transistor Q10; the first switch Q11 is used to drive the switches of the first conduction unit Q12 and the first turn-off unit; the first conduction unit Q12 connects the first energy storage element C1 to the gate of the charging MOS transistor Q10; the first turn-off unit connects the gate and source of the charging MOS transistor Q10; the discharging switch module includes a second energy storage element C2, a second switch Q21, a second conduction unit Q22, a second turn-off unit, and a discharging MOS transistor Q20; the second switch Q21 is used to drive the switches of the second conduction unit Q22 and the second turn-off unit; the second conduction unit Q22 connects the second energy storage element C2 to the gate of the discharging MOS transistor Q20; the second turn-off unit connects the gate and source of the discharging MOS transistor Q20; the charging switch and the discharging switch are connected in series at the output end of the battery B1; the analog front-end module U2 is used to collect data of the battery B1, including a first charging port CHG1 and a second charging port CHG2, which are respectively connected to the first energy storage element C1 and the second energy storage element C2; the main control module U1 is communicatively connected to the analog front-end module U2, including a charging control port CRL1 and a discharging control port CRL2, which are respectively connected to the control ends of the first switch Q11 and the second switch Q21. The other end of the discharging switch forms the positive output terminal OUT+ of the battery module, and the negative electrode of the battery B1 forms the negative output terminal OUT- of the battery module.

[0041] In some embodiments of this embodiment, there are multiple charging MOS and discharging MOS. The gates, sources, and drains of the charging MOS are respectively connected together, and the gates, sources, and drains of the discharging MOS are respectively connected together, so as to meet the relatively high charging or discharging current of the battery B1.

[0042] In this embodiment, the first energy storage element C1 and the second energy storage element C2 are energy storage capacitors. The energy storage capacitors have a low cost and a small leakage current, and are more suitable for the low-power design requirements of the BMS.

[0043] As a preference of this embodiment, the first switch Q11 and the second switch Q21 include small-signal N-channel field effect transistors. The first conduction unit Q12 and the second conduction unit Q22 include small-signal P-channel field effect transistors. The charging MOS transistor Q10 and the discharging MOS transistor Q20 are N-channel field effect transistors. Small-signal field effect transistors have the characteristics of small junction capacitance, small driving signal current, and fast switching speed. The fast switching of the charging and discharging MOS transistors Q20 can be achieved by controlling the small-signal field effect transistors through weak voltage signals.

[0044] In this embodiment, the first turn-off unit includes a first control switch transistor Q13 and a first drive switch transistor Q14; the control end of the first control switch transistor Q13 is connected to the output end of the first drive switch transistor Q14, the output end of the first control switch transistor Q13 is connected to the control end of the first drive switch transistor Q14, and the output end of the first drive switch transistor Q14 is connected to the gate and source of the discharge MOS transistor Q20; when the turn-off control signal is output from the charging control port CRL1, the first switch Q11 quickly turns off the first conduction unit Q12, cutting off the power supply circuit of the energy storage element to the charging MOS transistor Q10. At the same time, the first control switch transistor Q13 is controlled to conduct, thereby enabling the first drive switch transistor Q14 to conduct, short-circuiting the gate and drain of the charging MOS transistor Q10, and quickly discharging the charge of the junction capacitance of the charging MOS transistor Q10, achieving the quick turn-off of the charging MOS transistor Q10.

[0045] The second turn-off unit includes a second control switch transistor Q23 and a second drive switch transistor Q24. The control end of the second control switch transistor Q23 is connected to the output end of the second drive switch transistor Q24, the output end of the second control switch transistor Q23 is connected to the control end of the second drive switch transistor Q24, and the output end of the second drive switch transistor Q24 is connected to the gate and source of the charging MOS transistor Q10.

[0046] Preferably, in this embodiment, the first control switch transistor Q13 and the second control switch transistor Q23 are small-signal N-channel depletion-mode field-effect transistors; the first drive switch transistor Q14 and the second drive switch transistor Q24 are small-signal PNP bipolar transistors. Small-signal N-channel depletion-mode field-effect transistors and small-signal PNP bipolar transistors have characteristics such as small junction capacitance and fast switching speed. The small-signal N-channel depletion-mode field-effect transistor can be turned on with only a weak voltage signal, and the small-signal PNP bipolar transistor can achieve several times the current conduction control through a tiny current control.

[0047] Specifically, it further includes a first input resistor R11, a first voltage-dividing resistor R12, a second voltage-dividing resistor R13, a second input resistor R21, a third voltage-dividing resistor R22, and a fourth voltage-dividing resistor R23. The first input resistor R11 is connected to the first charging port CHG1 of the analog front-end module U2. The first end of the first voltage-dividing resistor R12 is connected to the source of the charging MOS transistor Q10, and the second end is connected to the base of the first control switch transistor Q13. The first end of the second voltage-dividing resistor R13 is connected to the base of the first control switch transistor Q13, and the second end is connected to the drain of the first switch Q11. The second input resistor R21 is connected to the second charging port CHG2 of the analog front-end module U2. The first end of the third voltage-dividing resistor R22 is connected to the source of the discharging MOS transistor Q20, and the second end is connected to the base of the second control switch transistor Q23. The first end of the fourth voltage-dividing resistor R23 is connected to the base of the second control switch transistor Q23, and the second end is connected to the drain of the second switch Q21.

[0048] Embodiment 2:

[0049] This embodiment provides a control method for a fast-driving battery management system. The battery management system is as described above. The method includes:

[0050] When driving the charging MOS transistor Q10 to conduct, the main control module U1 controls the first charging port CHG1 of the analog front-end module U2 to start charging, starts timing the charging time of the first energy storage element C1. When the charging time reaches the preset time, it controls the first charging port CHG1 of the analog front-end module U2 to stop charging, and controls the first switch Q11 to drive the first conducting unit Q12 to conduct.

[0051] When driving the discharging MOS transistor Q20 to conduct, the main control module U1 controls the second charging port CHG2 of the analog front-end module U2 to start charging, starts timing the charging time of the second energy storage element C2. When the charging time reaches the preset time, it controls the second charging port CHG2 of the analog front-end module U2 to stop charging, and controls the second switch Q21 to drive the second conducting unit Q22 to conduct.

[0052] Furthermore, the first energy storage element C1 and the second energy storage element C2 are energy storage capacitors, and the preset time satisfies:

[0053] t > 3RC;

[0054] where t is the preset time, R is the corresponding output impedance of the analog front-end module U2, and C is the capacitance value of the energy storage capacitor.

[0055] Further, the first energy storage element C1 and the second energy storage element C2 are energy storage capacitors. In the charging switch module and the discharging switch module, the capacitance value C of the energy storage capacitor satisfies:

[0056] C > 10 * Cj * (Vgs + Vbat) / Vgs;

[0057] wherein, Vbat is the maximum operating voltage of the battery B1;

[0058] In the charging switch module, Cj is the junction capacitance of the charging MOS transistor Q10, and Vgs is the driving voltage of the charging MOS transistor Q10;

[0059] In the discharging switch module, Cj is the junction capacitance of the discharging MOS transistor Q20, and Vgs is the driving voltage of the discharging MOS transistor Q20.

[0060] A battery management system with fast driving provided in this embodiment includes a main control module, an analog front-end module, and a fast driving circuit. The fast driving circuit includes an energy storage element, a driving switch, a conducting unit, a turning-off unit, and a charging and discharging MOS transistor. When controlling the charging and discharging MOS transistor to conduct, the main control module controls the analog front-end module to charge the energy storage element, and controls the driving switch to control the conducting unit to charge the junction capacitance of the charging and discharging MOS transistor with the energy storage element, so as to realize the fast conduction of the charging and discharging MOS transistor; when controlling the charging and discharging MOS transistor to turn off, the main control module controls the driving switch to control the turning-off unit to connect the gate and source of the charging and discharging MOS transistor, so that the junction capacitance discharges, and realizes the fast turning-off of the charging and discharging MOS transistor. Through the setting of the analog front-end module and the fast driving circuit, the present invention realizes the fast switching of the charging and discharging MOS transistor, and solves the problem of weak direct driving ability of the BMS chip.

[0061] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0062] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A fast-driven battery management system, characterized in that, It includes a main control module, an analog front-end module, and a fast drive circuit; The fast drive circuit includes a charging switch module and a discharging switch module; The charging switch module includes a first energy storage element, a first switch, a first conduction unit, a first turn-off unit, and a charging MOS transistor; the first switch is used to drive the switches of the first conduction unit and the first turn-off unit; The first conduction unit connects the first energy storage element to the gate of the charging MOS transistor; the first turn-off unit connects the gate and the source of the charging MOS transistor; The discharging switch module includes a second energy storage element, a second switch, a second conduction unit, a second turn-off unit, and a discharging MOS transistor; the second switch is used to drive the switches of the second conduction unit and the second turn-off unit; The second conduction unit connects the second energy storage element to the gate of the discharging MOS transistor; The second turn-off unit connects the gate and the source of the discharging MOS transistor; The charging switch and the discharging switch are connected in series at the output terminal of the battery; The analog front-end module is used to collect data of the battery, including a first charging port and a second charging port, which are respectively connected to the first energy storage element and the second energy storage element; The main control module is communicatively connected to the analog front-end module, including a charging control port and a discharging control port, which are respectively connected to the control ends of the first switch and the second switch.

2. The fast-driven battery management system according to claim 1, wherein, The first energy storage element and the second energy storage element are energy storage capacitors.

3. The battery management system with fast driving according to claim 1, characterized in that, The first switch and the second switch include small-signal N-channel field effect transistors.

4. A fast-driven battery management system according to claim 1, characterized in that, The first conduction unit and the second conduction unit include small-signal P-channel field effect transistors.

5. A fast-driven battery management system according to claim 1, characterized in that, The charging MOS transistor and the discharging MOS transistor are N-channel field effect transistors.

6. The battery management system with fast drive according to claim 1, wherein The first turn-off unit includes a first control switch transistor and a first drive switch transistor; the control end of the first control switch transistor is connected to the output end of the first drive switch transistor, the output end of the first control switch transistor is connected to the control end of the first drive switch transistor, and the output end of the first drive switch transistor is connected to the gate and the source of the discharging MOS transistor; The second turn-off unit includes a second control switch transistor and a second drive switch transistor, the control end of the second control switch transistor is connected to the output end of the second drive switch transistor, the output end of the second control switch transistor is connected to the control end of the second drive switch transistor, and the output end of the second drive switch transistor is connected to the gate and the source of the charging MOS transistor.

7. A fast-driven battery management system according to claim 6, characterized in that, The first control switch transistor and the second control switch transistor are small-signal N-channel depletion-mode field effect transistors; the first drive switch transistor and the second drive switch transistor are small-signal PNP bipolar transistors.

8. A control method for a fast-driven battery management system, characterized in that, The battery management system is as described in any one of claims 1 to 7, and the method includes: When driving the charging MOS transistor to conduct, the main control module controls the first charging port of the analog front-end module to start charging, and starts timing the charging time of the first energy storage element. When the charging time reaches the preset time, it controls the first charging port of the analog front-end module to stop charging, and controls the first switch to drive the first conducting unit to conduct; When driving the discharging MOS transistor to conduct, the main control module controls the second charging port of the analog front-end module to start charging, and starts timing the charging time of the second energy storage element. When the charging time reaches the preset time, it controls the second charging port of the analog front-end module to stop charging, and controls the second switch to drive the second conducting unit to conduct.

9. The control method of a fast-driven battery management system according to claim 8, characterized in that The first energy storage element and the second energy storage element are energy storage capacitors, and the preset time satisfies: t>3RC; where t is the preset time, R is the corresponding output impedance of the analog front-end module, and C is the capacitance value of the energy storage capacitor.

10. The control method of a fast-driven battery management system according to claim 8, characterized in that, The first energy storage element and the second energy storage element are energy storage capacitors. In the charging switch module and the discharging switch module, the capacitance value C of the energy storage capacitor satisfies: C>10*Cj*(Vgs+Vbat) / Vgs; where Vbat is the maximum operating voltage of the battery; In the charging switch module, Cj is the junction capacitance of the charging MOS transistor, and Vgs is the driving voltage of the charging MOS transistor; In the discharging switch module, Cj is the junction capacitance of the discharging MOS transistor, and Vgs is the driving voltage of the discharging MOS transistor.

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