High-voltage battery pack equalization control circuit and control method

Abstract

The invention provides a high-voltage battery pack equalization control circuit and a control method, the high-voltage battery pack equalization control circuit comprises an isolation transformer module, a first bridge switch module, a second bridge switch module, an isolation driver module and a monitoring module, by adopting the circuit provided by the invention, an efficient isolation transformer and an MOS (Metal Oxide Semiconductor) tube are used for realizing energy transmission, energy loss is reduced, and the service life of the high-voltage battery pack is prolonged. And meanwhile, the stability of energy conversion is ensured. The isolation driver module provides electrical isolation protection, avoids the influence of a high-voltage circuit on a low-voltage control circuit, improves the safety of the system, cooperates with the monitoring module, detects the current, voltage and balance state of a battery cell in real time, responds to an abnormal condition in time, and prevents a battery from being overcharged or overdischarged. The system adopts a modular design, and each cell is equipped with a DC-DC circuit, so that the system can be conveniently expanded.

Description

Technical Field

[0001] The present invention relates to the field of high-voltage battery pack control technology, and more specifically, to a high-voltage battery pack balancing control circuit and control method. Background Art

[0002] In the prior art, high-voltage battery packs usually achieve high voltage output by connecting multiple cells in series. The series connection scheme can effectively increase the output voltage of the battery pack, but it also has the following problems: High cell consistency requirements: The series cells need to be highly consistent, otherwise it will cause individual cells to be overcharged or over-discharged, affecting the performance and life of the battery pack. For systems with large battery scales, the cost of later maintenance is high. In terms of management complexity, series-connected batteries often need to be implemented using a centralized BMS, and the monitoring and management functions of all cells are concentrated in one master control unit. However, it may limit the scalability of larger battery systems and may introduce the possibility of single point failures. Distributed BMS is also often used to implement this, distributing the monitoring and management functions of the battery pack to multiple slave control units, each slave control unit is responsible for managing a small number of cells, and the master control unit is responsible for overall coordination and communication.

[0003] Existing high-voltage battery packs cannot achieve control and flexible adjustment of individual cells, making it difficult to improve system management efficiency. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a high-voltage battery pack balancing control circuit and control method to overcome the shortcomings of the existing high-voltage battery packs that cannot realize the control and flexible adjustment of each battery pack and it is difficult to improve the management efficiency of the system.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: In a first aspect, the present invention provides a high-voltage battery pack balancing control circuit, comprising: an isolation transformer module, used to convert a high voltage into a low voltage, and / or convert a low voltage into a high voltage; a first bridge switch module, at least used to convert direct current into alternating current, and / or convert alternating current into direct current; the first bridge switch module comprises a first side and a second side, the first side is electrically connected to the battery pack, and the second side is electrically connected to the primary side of the isolation transformer module; a second bridge switch module, at least used to convert direct current into alternating current, and / or convert alternating current into direct current; the second bridge switch module comprises a third side and a fourth side, the third side is electrically connected to an external circuit, and the fourth side is electrically connected to the isolation transformer module The secondary side of the block is electrically connected; an isolation driver module is used to output a drive signal to control the first bridge switch and / or the second bridge switch to be turned on or off; the first output end of the isolation driver module is electrically connected to the control end of the first bridge switch module; the second output end of the isolation driver module is electrically connected to the control end of the second bridge switch module; a monitoring module is used to at least detect the first current of the battery pack, and determine whether there is a balancing requirement based on the first current, and if so, send a balancing command to the isolation driver module; the negative electrode of the battery pack is electrically connected to the first bridge switch module after passing through the monitoring module, and the monitoring module is also communicatively connected to the isolation driver module.

[0006] In one embodiment, the first bridge switch module at least includes a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube; the gate of the first MOS tube, the gate of the second MOS tube, the gate of the third MOS tube and the gate of the fourth MOS tube are all connected to the isolation driver module; the drain of the first MOS tube and the drain of the second MOS tube are both electrically connected to the positive electrode of the battery pack; the source of the third MOS tube and the source of the fourth MOS tube are both electrically connected to the negative electrode of the battery pack; the source of the first MOS tube is electrically connected to the drain of the third MOS tube; the source of the second MOS tube is electrically connected to the drain of the fourth MOS tube; the source of the first MOS tube is electrically connected to the first end of the primary side of the isolation transformer module; the source of the second MOS tube is electrically connected to the second end of the primary side of the isolation transformer module.

[0007] In one embodiment, the second bridge switch module at least includes a fifth MOS tube, a sixth MOS tube, a seventh MOS tube and an eighth MOS tube; the gate of the fifth MOS tube, the gate of the sixth MOS tube, the gate of the seventh MOS tube and the gate of the eighth MOS tube are all connected to the isolation driver module; the drain of the fifth MOS tube and the drain of the sixth MOS tube are both electrically connected to the positive electrode of the external circuit; the source of the seventh MOS tube and the source of the eighth MOS tube are both electrically connected to the negative electrode of the external circuit; the source of the fifth MOS tube is electrically connected to the drain of the seventh MOS tube; the source of the sixth MOS tube is electrically connected to the drain of the eighth MOS tube; the source of the fifth MOS tube is electrically connected to the first end of the secondary side of the isolation transformer module; the source of the second MOS tube is electrically connected to the second end of the secondary side of the isolation transformer module.

[0008] In one embodiment, the isolation driver module includes a first pin, a second pin, a third pin and a fourth pin; the first pin is electrically connected to the gate of the first MOS tube; the second pin is electrically connected to the gate of the second MOS tube; the third pin is electrically connected to the gate of the third MOS tube; the fourth pin is electrically connected to the gate of the fourth MOS tube; during the discharge of the battery pack, the first pin and the fourth pin output a first level signal; the second pin and the third pin output a second level signal, and the first level signal and the second level signal are complementary signals.

[0009] In one embodiment, the isolation driver module also includes a fifth pin, a sixth pin, a seventh pin and an eighth pin; the fifth pin is electrically connected to the gate of the fifth MOS tube; the sixth pin is electrically connected to the gate of the sixth MOS tube; the seventh pin is electrically connected to the gate of the seventh MOS tube; the eighth pin is electrically connected to the gate of the eighth MOS tube; during the discharge of the battery pack, the sixth pin and the seventh pin output a third level signal, the fifth pin and the eighth pin output a fourth level signal, and the third level signal and the fourth level signal are complementary signals.

[0010] In one embodiment, the first bridge switch module further includes: a ninth MOS tube, a tenth MOS tube, an eleventh MOS tube and a twelfth MOS tube; the gate of the ninth MOS tube, the gate of the tenth MOS tube, the gate of the eleventh MOS tube and the gate of the twelfth MOS tube are all connected to the isolation driver module; the drain of the ninth MOS tube and the drain of the tenth MOS tube are both electrically connected to the positive electrode of the battery pack; the source of the eleventh MOS tube and the source of the twelfth MOS tube are both electrically connected to the negative electrode of the battery pack; the source of the ninth MOS tube is electrically connected to the drain of the eleventh MOS tube; the source of the tenth MOS tube is electrically connected to the drain of the twelfth MOS tube; the source of the ninth MOS tube is electrically connected to the third end of the primary side of the isolation transformer module; the source of the tenth MOS tube is electrically connected to the fourth end of the primary side of the isolation transformer module.

[0011] In one embodiment, the monitoring module includes: a shunt and a comparator unit; the negative electrode of the battery pack is electrically connected to the first bridge switch module through the shunt; the output end of the shunt is electrically connected to the input end of the comparator unit; the output end of the comparator unit is communicatively connected to the isolation driver module.

[0012] In one embodiment, the shunt includes: a first sampling resistor, a second sampling resistor, a third sampling resistor and a fourth sampling resistor; a first end of the first sampling resistor, a first end of the second sampling resistor, a first end of the third sampling resistor and a first end of the fourth sampling resistor are all electrically connected to the negative electrode of the battery pack; a second end of the first sampling resistor, a second end of the second sampling resistor, a second end of the third sampling resistor and a second end of the fourth sampling resistor are all electrically connected to the first bridge switch module; a first end of the first sampling resistor, a first end of the second sampling resistor, a first end of the third sampling resistor and a first end of the fourth sampling resistor are all electrically connected to the first pin of the comparator unit; a second end of the first sampling resistor, a second end of the second sampling resistor, a second end of the third sampling resistor and a second end of the fourth sampling resistor are all electrically connected to the second pin of the comparator unit.

[0013] In one embodiment, a fuse is further included; the positive electrode of the battery pack is electrically connected to the first bridge switch module through the fuse.

[0014] In a second aspect, the present invention further provides a high-voltage battery pack balancing control method, which is applied to the control circuit of the first aspect, and the method includes: In response to an external control signal, the isolation driver module is used to output a driving signal to the first bridge switch module and / or the second bridge switch module respectively, so that the first bridge switch module converts direct current into alternating current and the second bridge switch module converts alternating current into direct current; or the first bridge switch module converts alternating current into direct current and the second bridge switch module converts direct current into alternating current; Using the monitoring module to detect at least the negative electrode current of the battery pack, and judging whether there is a power balancing requirement based on the detection result of the monitoring module, and if so, sending a balancing command to the isolation driver module; In response to the balancing command, the isolation driver module cuts off the first bridge switch module and / or the second bridge switch module to prevent the battery pack from being overcharged or over-discharged.

[0015] In summary, the present invention has the following beneficial effects: a high-voltage battery pack balancing control circuit, comprising: an isolation transformer module, a first bridge switch module, a second bridge switch module, an isolation driver module and a monitoring module. The circuit of the present invention uses an efficient isolation transformer and a MOS tube for energy transmission, which reduces energy loss and ensures the stability of energy conversion. The isolation driver module provides electrical isolation protection, avoids the influence of the high-voltage circuit on the low-voltage control circuit, improves the safety of the system, cooperates with the monitoring module to detect the current, voltage and balancing state of the battery cell in real time, responds to abnormal conditions in time, and prevents the battery from being overcharged or over-discharged; the system adopts a modular design, and each battery cell is equipped with a DC-DC circuit, which can facilitate the expansion of the system. When the battery packs are connected in parallel, each battery pack can act as a host to control the remaining battery packs for power balancing, avoiding the disadvantage that the remaining battery packs cannot achieve power balancing after the host battery pack is offline. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A topological diagram of a high-voltage battery pack balancing control circuit of the present invention; Figure 2 A schematic diagram of a high-voltage battery pack balancing control circuit of the present invention; Figure 3 This is a schematic diagram of the circuit of the first bridge switch module of the present invention; Figure 4 The monitoring module circuit diagram of the present invention; Figure 5 This is a circuit schematic diagram of the second bridge switch module of the present invention; Figure 6 It is the circuit principle diagram of the temperature detection module of the present invention; Figure 7 It is a schematic diagram of the MCU chip circuit of the present invention; Figure 8 is a schematic diagram of a high-speed sampling circuit of the present invention; Fig. 9 This is a flow chart of the high-voltage battery pack balancing control method of the present invention.

[0017] In the figure: 1. Isolation transformer module; 2. First bridge switch module; 3. Second bridge switch module; 4. Isolation driver module; 5. Monitoring module. DETAILED DESCRIPTION

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0019] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The terms "vertical", "horizontal", "left", "right", "above", "below" and similar expressions are for illustrative purposes only, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Embodiment 1

[0021] In order to solve the above problems, the present invention provides a high-voltage battery pack balancing control circuit, such as Figure 1 As shown, including: An isolation transformer module 1, used for converting a high voltage into a low voltage, and / or converting a low voltage into a high voltage; A first bridge switch module 2, at least used for converting direct current into alternating current, and / or converting alternating current into direct current; the first bridge switch module 2 comprises a first side and a second side, the first side is electrically connected to the battery pack, and the second side is electrically connected to the primary side of the isolation transformer module 1; The second bridge switch module 3 is at least used to convert direct current into alternating current, and / or to convert alternating current into direct current; the second bridge switch module 3 includes a third side and a fourth side, the third side is electrically connected to the external circuit, and the fourth side is electrically connected to the secondary side of the isolation transformer module 1; an isolation driver module 4, configured to output a drive signal to control the first bridge switch and / or the second bridge switch to be turned on or off; a first output end of the isolation driver module 4 is electrically connected to a control end of the first bridge switch module 2; a second output end of the isolation driver module 4 is electrically connected to a control end of the second bridge switch module 3; The monitoring module 5 is used to at least detect the first current of the battery pack and determine whether there is a balancing requirement based on the first current. If so, a balancing command is sent to the isolation driver module 4; the negative electrode of the battery pack is electrically connected to the first bridge switch module 2 after passing through the monitoring module 5, and the monitoring module 5 is also communicatively connected to the isolation driver module 4.

[0022] In practical applications, by setting up the isolation transformer module 1, high voltage can be converted into low voltage, or low voltage can be converted into high voltage, so as to perform effective energy transmission between different voltage levels and ensure the flexibility and efficiency of the system. The isolation transformer can also ensure that the battery pack and the external circuit are isolated from each other, thereby improving the safety of the circuit. The first bridge switch module 2 and the second bridge switch module 3 can perform bidirectional conversion between direct current and alternating current, so that the system can realize the voltage conversion function of DC-DC, and the bridge switch module can control its opening or closing according to actual needs to achieve the balance of power between the battery packs. The isolation driver module 4 can provide a driving signal for the first bridge switch and the second bridge switch to ensure the precise control of the switch state. The isolation driver module 4 can provide a pure digital driving signal with the advantages of high precision and high speed. In the present application, by monitoring the current and voltage and adjusting the charge and discharge state of the battery pack according to the real-time situation, the situation of overcharging or overdischarging can be effectively avoided, and the service life and safety of the battery pack can be improved.

[0023] In one embodiment, the first bridge switch module at least includes a first MOS tube MOS1, a second MOS tube MOS2, a third MOS tube MOS3 and a fourth MOS tube MOS4; the gate of the first MOS tube MOS1, the gate of the second MOS tube MOS2, the gate of the third MOS tube MOS3 and the gate of the fourth MOS tube MOS4 are all connected to the isolation driver module; the drain of the first MOS tube MOS1 and the drain of the second MOS tube MOS2 are both electrically connected to the positive electrode of the battery pack; the source of the third MOS tube MOS3 and the source of the fourth MOS tube MOS4 are both electrically connected to the negative electrode of the battery pack; the source of the first MOS tube MOS1 is electrically connected to the drain of the third MOS tube MOS3; the source of the second MOS tube MOS2 is electrically connected to the drain of the fourth MOS tube MOS4; the source of the first MOS tube MOS1 is electrically connected to the first end of the primary side of the isolation transformer module; the source of the second MOS tube MOS2 is electrically connected to the second end of the primary side of the isolation transformer module.

[0024] In one embodiment, the second bridge switch module at least includes a fifth MOS tube MOS5, a sixth MOS tube MOS6, a seventh MOS tube MOS7 and an eighth MOS tube MOS8; the gate of the fifth MOS tube MOS5, the gate of the sixth MOS tube MOS6, the gate of the seventh MOS tube MOS7 and the gate of the eighth MOS tube MOS8 are all connected to the isolation driver module; the drain of the fifth MOS tube MOS5 and the drain of the sixth MOS tube MOS6 are both electrically connected to the positive electrode of the external circuit; the source of the seventh MOS tube MOS7 and the source of the eighth MOS tube MOS8 are both electrically connected to the negative electrode of the external circuit; the source of the fifth MOS tube MOS5 is electrically connected to the drain of the seventh MOS tube MOS7; the source of the sixth MOS tube MOS6 is electrically connected to the drain of the eighth MOS tube MOS8; the source of the fifth MOS tube MOS5 is electrically connected to the first end of the secondary side of the isolation transformer module; the source of the second MOS tube MOS2 is electrically connected to the second end of the secondary side of the isolation transformer module.

[0025] In one embodiment, the isolation driver module includes a first pin, a second pin, a third pin and a fourth pin; the first pin is electrically connected to the gate of the first MOS tube MOS1; the second pin is electrically connected to the gate of the second MOS tube MOS2; the third pin is electrically connected to the gate of the third MOS tube MOS3; the fourth pin is electrically connected to the gate of the fourth MOS tube MOS4; during the discharge of the battery pack, the first pin and the fourth pin output a first level signal; the second pin and the third pin output a second level signal, and the first level signal and the second level signal are complementary signals.

[0026] In one embodiment, the isolation driver module further includes a fifth pin, a sixth pin, a seventh pin and an eighth pin; the fifth pin is electrically connected to the gate of the fifth MOS tube MOS5; the sixth pin is electrically connected to the gate of the sixth MOS tube MOS6; the seventh pin is electrically connected to the gate of the seventh MOS tube MOS7; the eighth pin is electrically connected to the gate of the eighth MOS tube MOS8; during the discharge of the battery pack, the sixth pin and the seventh pin output a third level signal, the fifth pin and the eighth pin output a fourth level signal, and the third level signal and the fourth level signal are complementary signals.

[0027] In practical applications, the first bridge switch module and the second bridge switch module respectively convert the DC power of the battery pack into AC power through the alternating conduction and disconnection of the MOS tube to pass through the isolation transformer, or convert the AC power output by the isolation transformer into DC power to charge the battery pack or discharge it to the external circuit. This bidirectional control method, especially the efficient power conversion achieved by the MOS tube, improves the utilization efficiency of the battery pack and enables the parallel battery system to work stably in different states; by using multiple MOS tubes in the first bridge switch module and the second bridge switch module, and connecting their gates to the isolation driver module, the conduction and disconnection states of each MOS tube can be accurately controlled. The gate signal of each MOS tube is a complementary signal provided by the isolation driver module, which can ensure the coordinated operation of the switch, thereby achieving accurate control of the battery pack and avoiding uneven power between batteries; the isolation driver module adjusts the switch state of the MOS tube according to the charge and discharge state of the battery pack to ensure that the battery pack can maintain a relatively balanced power distribution during the charging and discharging process, thereby extending the battery life and improving the use efficiency of the entire battery system; the isolation driver module has multiple pins connected to the MOS tube, and can output different level signals during the discharge process of the battery pack to control the working state of different bridge modules. Through multi-channel control, power balancing of multiple battery packs in parallel can be achieved, improving the charging and discharging efficiency and control accuracy of the entire battery system.

[0028] In one embodiment, the first bridge switch module further includes: a ninth MOS tube, a tenth MOS tube, an eleventh MOS tube and a twelfth MOS tube; the gate of the ninth MOS tube, the gate of the tenth MOS tube, the gate of the eleventh MOS tube and the gate of the twelfth MOS tube are all connected to the isolation driver module; the drain of the ninth MOS tube and the drain of the tenth MOS tube are both electrically connected to the positive electrode of the battery pack; the source of the eleventh MOS tube and the source of the twelfth MOS tube are both electrically connected to the negative electrode of the battery pack; the source of the ninth MOS tube is electrically connected to the drain of the eleventh MOS tube; the source of the tenth MOS tube is electrically connected to the drain of the twelfth MOS tube; the source of the ninth MOS tube is electrically connected to the third end of the primary side of the isolation transformer module; the source of the tenth MOS tube is electrically connected to the fourth end of the primary side of the isolation transformer module.

[0029] In the scenario of connecting multiple battery packs in parallel, the current may be large. Therefore, designing an additional set of MOS tubes for use in parallel can significantly improve the current carrying capacity of the system and ensure that the system can still operate stably under high load conditions. In addition, by adding a set of parallel MOS tubes, when one MOS tube fails, the other parallel MOS tubes can still continue to work, increasing the redundancy and reliability of the system.

[0030] In one embodiment, the monitoring module includes: a shunt and a comparator unit; the negative electrode of the battery pack is electrically connected to the first bridge switch module through the shunt; the output end of the shunt is electrically connected to the input end of the comparator unit; the output end of the comparator unit is communicatively connected to the isolation driver module.

[0031] In practical applications, the detection of negative electrode current can accurately monitor the charging and discharging process of the battery pack. By detecting the negative electrode current of the battery pack through a shunt or other means, the current data of the battery pack can be obtained, so as to understand the discharge of the battery pack. Since the current flows out from the negative electrode of the battery pack, monitoring this current can effectively reflect the load condition of the battery pack and whether the battery pack is working properly. When multiple battery packs are used in parallel, the power, charging state and internal resistance of different battery packs may be different, resulting in uneven current between battery packs. The detection of negative electrode current helps to detect this imbalance. By detecting the negative electrode current, it can be determined which battery pack has a high or low current, and then it can be determined whether it is necessary to perform power balancing operations between battery packs. Timely discovery and adjustment can ensure that the power of multiple battery packs is consistent and prevent some battery packs from over-discharging or over-charging. The comparator unit not only has the function of current detection, but also has a 485 communication interface, which can transmit the detection results to the main control device in a timely manner, and the main control device determines whether there is a situation where power balancing is required. If so, the corresponding battery pack is controlled to perform power balancing operations.

[0032] In one embodiment, Figure 3 As shown, each MOS tube is provided with a gate capacitor, which is connected in parallel between the gate and the source to stabilize the gate voltage, suppress high-frequency noise, and prevent the MOS tube from being triggered by mistake; each MOS tube is also provided with a source-drain capacitor, which is connected between the source and the drain and the ground or the power supply to smooth the current fluctuation and reduce the voltage spike during the switching transient. A capacitor group is also connected in parallel at the output end of the first bridge switch module, which is used to suppress high-frequency ripple and improve the quality of the output current. A gate resistor is also provided on each MOS tube, which is used to limit the gate charging current, prevent oscillation caused by parasitic capacitance, and optimize the switching speed.

[0033] In one embodiment, Figure 4As shown, the shunt includes: a first sampling resistor RS1, a second sampling resistor RS2, a third sampling resistor RS3 and a fourth sampling resistor RS4; the first end of the first sampling resistor RS1, the first end of the second sampling resistor RS2, the first end of the third sampling resistor RS3 and the first end of the fourth sampling resistor RS4 are all electrically connected to the negative electrode of the battery pack; the second end of the first sampling resistor RS1, the second end of the second sampling resistor RS2, the second end of the third sampling resistor RS3 and the second end of the fourth sampling resistor RS4 are all electrically connected to the first bridge switch module; the first end of the first sampling resistor RS1, the first end of the second sampling resistor RS2, the first end of the third sampling resistor RS3 and the first end of the fourth sampling resistor RS4 are all electrically connected to the first pin of the comparator unit; the second end of the first sampling resistor RS1, the second end of the second sampling resistor RS2, the second end of the third sampling resistor RS3 and the second end of the fourth sampling resistor RS4 are all electrically connected to the second pin of the comparator unit.

[0034] In practical applications, four sampling resistors are set so that the total resistance value after parallel connection is 1 / 4 of a single resistor (assuming four identical resistors). According to the shunt principle, the current is evenly distributed to four branches. The impact of the resistance error of a single resistor on the total measurement is reduced, and the resistance drift caused by overheating is significantly reduced. The parallel design of four sampling resistors can also provide redundancy to avoid circuit open circuits. Even if one of the resistors is open, the remaining three can continue to work, avoiding single point failures that cause the entire current measurement to fail. Figure 7 As shown, the comparator unit specifically includes: an MCU chip, and the MCU chip specifically adopts an MCU chip of model TMS320F28034PNT; wherein the comparator unit can convert the analog signal into a digital signal according to the sampling data of the first pin and the third pin, and remotely communicate the sampling data with the external control device from the eleventh pin and the thirteenth pin, the eleventh pin and the thirteenth pin are RS485 signal transmission pins, and the comparator unit transmits differential signals through twisted pair cables, effectively suppresses common mode interference, and supports long-distance communication.

[0035] like Figure 8 As shown, the high-speed sampling circuit includes a high-speed current sampling circuit and a high-speed voltage sampling circuit. The specific working principle of the high-speed voltage sampling circuit is: the voltage signal to be measured enters the circuit through INP. If the input voltage exceeds the input range of the operational amplifier, the amplitude is adjusted through the resistor voltage divider network; the operational amplifier U10A / S amplifies the differential signal to improve the signal-to-noise ratio of the small signal; the capacitor filters out high-frequency noise, and the voltage regulator diode limits the upper limit of the output voltage to prevent overvoltage from damaging the subsequent circuit, and finally outputs a stable differential or single-ended voltage signal for comparison and processing by the MCU chip.

[0036] The working principle of the high-speed current sampling circuit is as follows: the sampling resistor R45 converts the input current into a small voltage signal, and the operational amplifier U14A, as a transimpedance amplifier, amplifies the voltage signal on R45 and outputs it as a voltage signal suitable for subsequent processing; the DC bias of the operational amplifier is adjusted by an adjustable voltage source to eliminate input offset or zero drift, and the capacitor filters high-frequency noise; the power pin realizes analog / digital power isolation to reduce interference. The final output signal (OUTN / OUTP) is a voltage signal proportional to the input current, which is connected to the MCU chip for processing.

[0037] In one embodiment, Figure 5 As shown, the monitoring module also includes a fifth sampling resistor RS5. The negative electrode of the second bridge switch module is electrically connected to the external circuit through the fifth sampling resistor RS5. The fifth sampling resistor is used to detect the current between the DC-DC module and the external circuit to determine whether the battery pack needs to be balanced.

[0038] In one embodiment, Figure 5 As shown, it also includes a relay module, the positive electrode of the second bridge switch module is electrically connected to the external circuit through the relay module, and the relay module can be based on the external device (that is, Figure 1 The control signal of the MCU module in the DC-DC module controls the conduction or disconnection between the DC-DC module and the external circuit.

[0039] In one embodiment, an AFE module is also included. The AFE module is used to collect analog signals such as voltage, current, temperature, etc. of each battery cell in the battery pack, and convert them into digital signals for processing by the main controller. The AFE module is communicated with an external MCU module and can detect each battery cell in the battery pack. In the event of a failure in a certain battery cell, it can also provide timely feedback to the MCU to take the battery pack offline for maintenance personnel to perform maintenance.

[0040] In one embodiment, Figure 6 As shown, it also includes a temperature detection module, which can detect the temperature inside the battery pack. When the temperature in the battery pack is abnormal, when it is detected that the battery cell temperature is too low, the built-in heating film is activated to keep the battery at an efficient charging and discharging temperature. If the temperature is too high, the battery will trigger protection and will not allow charging or discharging.

[0041] In summary, the present application provides a battery pack control circuit, which reduces energy loss and ensures the stability of energy conversion by setting up efficient isolation transformers and MOS tubes for energy transmission. The isolation driver module provides electrical isolation protection, avoids the influence of high-voltage circuits on low-voltage control circuits, improves the safety of the system, cooperates with the monitoring module to detect the current, voltage and balance state of the battery cell in real time, responds to abnormal conditions in time, and prevents battery overcharge or over-discharge; the system adopts a modular design, and each battery cell is equipped with a DC-DC circuit, which can facilitate the expansion of the system. When the battery packs are connected in parallel, each battery pack can act as a host to control the remaining battery packs for power balancing, avoiding the disadvantage that the remaining battery packs cannot achieve power balancing after the host battery pack is offline. Embodiment 2

[0042] A high-voltage battery pack balancing control method, comprising: S1. In response to an external control signal, using the isolation driver module to output a drive signal to the first bridge switch module and / or the second bridge switch module, respectively, so that the first bridge switch module converts direct current into alternating current, and the second bridge switch module converts alternating current into direct current; or, so that the first bridge switch module converts alternating current into direct current, and the second bridge switch module converts direct current into alternating current; S2, using the monitoring module to detect at least the negative electrode current of the battery pack, and judging whether there is a power balancing requirement based on the detection result of the monitoring module, and if so, sending a balancing command to the isolation driver module; S3. In response to the balancing command, the isolation driver module cuts off the first bridge switch module and / or the second bridge switch module to prevent the battery pack from being overcharged or over-discharged.

[0043] In this embodiment, each pin of the isolation driver module is connected to the gate of each MOS tube, and the MOS tube can be turned on or off based on the isolation driver module. When the isolation driver module outputs a high level, the MOS tube is turned on, and when the isolation driver module outputs a low level, the MOS tube is turned off. Therefore, the isolation driver module can output alternating high and low levels to turn on different MOS tubes, so that the direct current passing through the isolation transformer is continuously changed in direction and converted into alternating current, and the voltage conversion is realized by using the transformer.

[0044] The monitoring module includes four parallel sampling resistors, which can monitor the negative current of the battery pack. When the negative current of the battery pack is abnormal, the monitoring module can send the abnormal current data to the isolation driver module in time, and the isolation driver module can convert all the output levels to low levels in time, so that the front and rear MOS tubes of the isolation transformer are all turned off to avoid overcharging or over-discharging of the battery pack. Through external MCU control, other battery packs can also be used to actively balance the overcharged or over-discharged battery packs, transfer the power of the overcharged battery to other battery packs, or use other battery packs to charge the over-discharged battery packs to avoid further over-discharging of the battery packs.

[0045] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0046] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-voltage battery pack balancing control circuit, characterized in that: include: Isolation transformer modules for converting high voltage to low voltage and / or converting low voltage to high voltage; a first bridge switch module, at least used for converting direct current into alternating current, and / or converting alternating current into direct current; the first bridge switch module comprises a first side and a second side, the first side is electrically connected to the battery pack, and the second side is electrically connected to the primary side of the isolation transformer module; a second bridge switch module, at least used for converting direct current into alternating current, and / or converting alternating current into direct current; the second bridge switch module comprises a third side and a fourth side, the third side is electrically connected to an external circuit, and the fourth side is electrically connected to a secondary side of the isolation transformer module; an isolation driver module, configured to output a drive signal to control the first bridge switch and / or the second bridge switch to be turned on or off; a first output terminal of the isolation driver module is electrically connected to a control terminal of the first bridge switch module; The second output terminal of the isolation driver module is electrically connected to the control terminal of the second bridge switch module; A monitoring module is used to at least detect a first current of the battery pack and determine whether there is a balancing requirement based on the first current. If so, a balancing command is sent to the isolation driver module; the negative electrode of the battery pack is electrically connected to the first bridge switch module after passing through the monitoring module, and the monitoring module is also communicatively connected to the isolation driver module.

2. A high-voltage battery pack balancing control circuit according to claim 1, characterized in that: The first bridge switch module at least includes a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor; The gate of the first MOS tube, the gate of the second MOS tube, the gate of the third MOS tube and the gate of the fourth MOS tube are all connected to the isolation driver module; The drain of the first MOS tube and the drain of the second MOS tube are both electrically connected to the positive electrode of the battery pack; The source electrode of the third MOS tube and the source electrode of the fourth MOS tube are both electrically connected to the negative electrode of the battery pack; The source of the first MOS tube is electrically connected to the drain of the third MOS tube; The source of the second MOS tube is electrically connected to the drain of the fourth MOS tube; The source of the first MOS transistor is electrically connected to the first end of the primary side of the isolation transformer module; the source of the second MOS transistor is electrically connected to the second end of the primary side of the isolation transformer module.

3. A high-voltage battery pack balancing control circuit according to claim 2, characterized in that: The second bridge switch module at least includes a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor and an eighth MOS transistor; The gate of the fifth MOS tube, the gate of the sixth MOS tube, the gate of the seventh MOS tube and the gate of the eighth MOS tube are all connected to the isolation driver module; The drain of the fifth MOS tube and the drain of the sixth MOS tube are both electrically connected to the positive electrode of the external circuit; The source electrode of the seventh MOS tube and the source electrode of the eighth MOS tube are both electrically connected to the negative electrode of the external circuit; The source of the fifth MOS tube is electrically connected to the drain of the seventh MOS tube; The source of the sixth MOS tube is electrically connected to the drain of the eighth MOS tube; The source of the fifth MOS transistor is electrically connected to the first end of the secondary side of the isolation transformer module; the source of the second MOS transistor is electrically connected to the second end of the secondary side of the isolation transformer module.

4. A high-voltage battery pack balancing control circuit according to claim 3, characterized in that: The isolation driver module includes a first pin, a second pin, a third pin and a fourth pin; The first pin is electrically connected to the gate of the first MOS tube; The second pin is electrically connected to the gate of the second MOS tube; The third pin is electrically connected to the gate of the third MOS tube; The fourth pin is electrically connected to the gate of the fourth MOS tube; During the discharge of the battery pack, the first pin and the fourth pin output a first level signal; the second pin and the third pin output a second level signal, and the first level signal and the second level signal are complementary signals.

5. A high-voltage battery pack balancing control circuit according to claim 3, characterized in that: The isolation driver module further includes a fifth pin, a sixth pin, a seventh pin and an eighth pin; The fifth pin is electrically connected to the gate of the fifth MOS tube; The sixth pin is electrically connected to the gate of the sixth MOS tube; The seventh pin is electrically connected to the gate of the seventh MOS tube; The eighth pin is electrically connected to the gate of the eighth MOS tube; During the discharge of the battery pack, the sixth pin and the seventh pin output a third level signal, the fifth pin and the eighth pin output a fourth level signal, and the third level signal and the fourth level signal are complementary signals.

6. A high-voltage battery pack balancing control circuit according to claim 2, characterized in that: The first bridge switch module further includes: a ninth MOS transistor, a tenth MOS transistor, an eleventh MOS transistor and a twelfth MOS transistor; The gate of the ninth MOS tube, the gate of the tenth MOS tube, the gate of the eleventh MOS tube and the gate of the twelfth MOS tube are all connected to the isolation driver module; The drain of the ninth MOS tube and the drain of the tenth MOS tube are both electrically connected to the positive electrode of the battery pack; The source electrode of the eleventh MOS tube and the source electrode of the twelfth MOS tube are both electrically connected to the negative electrode of the battery pack; The source of the ninth MOS tube is electrically connected to the drain of the eleventh MOS tube; The source of the tenth MOS tube is electrically connected to the drain of the twelfth MOS tube; The source of the ninth MOS transistor is electrically connected to the third end of the primary side of the isolation transformer module; the source of the tenth MOS transistor is electrically connected to the fourth end of the primary side of the isolation transformer module.

7. A high-voltage battery pack balancing control circuit according to claim 1, characterized in that: The monitoring module includes: a shunt and a comparator unit; the negative electrode of the battery pack is electrically connected to the first bridge switch module through the shunt; The output end of the shunt is electrically connected to the input end of the comparator unit; and the output end of the comparator unit is communicatively connected to the isolation driver module.

8. A high-voltage battery pack balancing control circuit according to claim 7, characterized in that: The shunt comprises: a first sampling resistor, a second sampling resistor, a third sampling resistor and a fourth sampling resistor; The first end of the first sampling resistor, the first end of the second sampling resistor, the first end of the third sampling resistor, and the first end of the fourth sampling resistor are all electrically connected to the negative electrode of the battery pack; the second end of the first sampling resistor, the second end of the second sampling resistor, the second end of the third sampling resistor, and the second end of the fourth sampling resistor are all electrically connected to the first bridge switch module; The first end of the first sampling resistor, the first end of the second sampling resistor, the first end of the third sampling resistor and the first end of the fourth sampling resistor are all electrically connected to the first pin of the comparator unit; The second end of the first sampling resistor, the second end of the second sampling resistor, the second end of the third sampling resistor, and the second end of the fourth sampling resistor are all electrically connected to the second pin of the comparator unit.

9. A high-voltage battery pack balancing control circuit according to claim 8, characterized in that: It also includes a fuse; the positive electrode of the battery pack is electrically connected to the first bridge switch module through the fuse.

10. A high-voltage battery pack balancing control method, characterized in that: Applied to the high-voltage battery pack balancing control circuit as claimed in any one of claims 1 to 9, the control method comprises: In response to an external control signal, the isolation driver module is used to output a driving signal to the first bridge switch module and / or the second bridge switch module respectively, so that the first bridge switch module converts direct current into alternating current and the second bridge switch module converts alternating current into direct current; or the first bridge switch module converts alternating current into direct current and the second bridge switch module converts direct current into alternating current; Using the monitoring module to detect at least the negative electrode current of the battery pack, and judging whether there is a power balancing requirement based on the detection result of the monitoring module, and if so, sending a balancing command to the isolation driver module; In response to the balancing command, the isolation driver module cuts off the first bridge switch module and / or the second bridge switch module to prevent the battery pack from being overcharged or over-discharged.

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