Active equalization device of lithium battery and preparation method

Abstract

The invention discloses an active equalization device of a lithium battery and a preparation method, and the method comprises the steps: preparing a battery active equalization module used for carrying out the active equalization of a battery pack, and the battery active equalization module comprises an isolation power supply module and a lithium battery charging management chip; preparing a power supply module for supplying power to the battery active equalization module; preparing an automatic switch module for automatically controlling whether the power supply module supplies power to the battery active equalization module or not; the lead is connected with the power module and the automatic switch module, and the lead is connected with the power module and the battery active equalization module to obtain an active equalization device; and the battery active equalization module is used for starting an active equalization function when the power supply of the power supply module is obtained and closing the active equalization function when the power supply of the power supply module is lost. The active equalization device is low in cost, whether active equalization is started or not can be automatically controlled, preparation is efficient and rapid, and the integrated active equalization device can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery equalization circuits, and in particular to an active equalization device for a lithium battery and a preparation method thereof. Background Art

[0002] Lithium battery balancing technology plays a vital role in electric vehicles, energy storage systems and other fields. With the continuous development of new energy technologies, lithium batteries have been widely used as an efficient and reliable energy storage device. However, the phenomenon of different parameters such as battery capacity, SOC, internal resistance and voltage due to internal differences or different external usage states of the battery is called battery inconsistency. Due to the internal inconsistency of lithium batteries, the performance and service life of the battery pack will be seriously affected.

[0003] In order to reduce the impact of internal inconsistencies in lithium batteries on battery pack performance, the batteries need to be balanced. Currently, there are two types of battery balancing: passive balancing and active balancing.

[0004] The advantages of passive balancing are simple circuit structure and low cost; the disadvantages are low energy utilization and increased heat dissipation of the module. If the battery is detected to be unbalanced, passive balancing selectively closes the discharge circuit of the high-energy single battery, closes the switch, and discharges the cells with higher energy in the battery pack through the resistance in the circuit, consuming the high energy, thereby reducing the gap between the cells and finally achieving a balanced state. Since this balancing method is a passive energy consumption, it is called passive balancing.

[0005] The advantages of active balancing are fast balancing speed and high energy utilization; the disadvantages are complex circuits and high costs. Active balancing is to transfer energy from high-energy batteries to low-energy batteries in the battery pack to achieve energy transfer balancing, thereby reducing the gap between cells and ultimately achieving a balanced state. Because it is an active energy transfer, it is called active balancing.

[0006] Currently, mainstream active balancing devices all use pulsed current to actively balance the battery. There is a lack of an active balancing device and a preparation method for constant current active balancing that can automatically switch on and off, is inexpensive, and has a simple structure. Therefore, a preparation method for an active balancing device for a lithium battery is needed. Summary of the invention

[0007] In view of the above problems, the present invention provides an active equalization device for a lithium battery and a preparation method thereof.

[0008] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0009] In a first aspect, the present invention provides a method for preparing an active equalization device for a lithium battery, comprising:

[0010] Prepare a battery active balancing module for actively balancing a battery pack, wherein the battery active balancing module includes an isolation power module and a lithium battery charging management chip;

[0011] Prepare a power module for supplying power to the battery active balancing module;

[0012] Prepare an automatic switch module for automatically controlling whether the power module supplies power to the battery active balancing module;

[0013] The wire connects the power module and the automatic switch module, and the wire connects the power module and the battery active balancing module to obtain an active balancing device.

[0014] In a preferred embodiment, the preparation of the battery active balancing module for actively balancing the battery pack specifically includes: setting the charging voltage and charging current for the lithium battery charging management chip, using EDA software to draw the circuit schematic diagram of the battery active balancing module, drawing the PCB, performing SMT patching, and obtaining the battery active balancing module.

[0015] In a preferred embodiment, the isolated power supply module has a short circuit protection function, and the lithium battery charging management chip is a lithium battery charging management chip for a single string of lithium batteries.

[0016] In a preferred embodiment, the automatic switch module includes an operational amplifier device or a comparator device. The specific process of preparing the automatic switch module is: according to the number of balanced battery groups, the equalization start voltage threshold is selected, and the operational amplifier device or the comparator device is selected; using EDA software to draw the circuit schematic diagram of the automatic start equalization module, draw the PCB, perform SMT patch, and obtain the automatic start equalization module.

[0017] In a preferred embodiment, the operating power consumption of the operational amplifier device is less than 50 μA.

[0018] In a preferred embodiment, the automatic switch module includes resistors, and the accuracy of all resistors in the automatic switch module is 0.1%.

[0019] In a preferred embodiment, the power module includes a switching power chip, a power inductor, a capacitor and a resistor; the preparation process of the power module is specifically as follows: according to the number of balanced battery cell strings, input voltage, input power, output voltage, output power, and conversion efficiency, a switching power chip, a power inductor, a capacitor, and a resistor are selected, and a circuit schematic is drawn using EDA software, a PCB is drawn, and SMT patch is performed to obtain a power module.

[0020] In a preferred embodiment, the switching power supply chip conversion efficiency is greater than 90%.

[0021] In a preferred embodiment, the battery active balancing module includes a VIN interface, a ground interface, a lithium battery positive electrode interface and a lithium battery negative electrode interface; the power module includes an output port, a switch port, a positive input port and a negative input port; the automatic switch module includes a switch port, a positive input port and a negative input port; the battery active balancing module includes a VIN interface, a ground interface, a lithium battery positive electrode interface and a lithium battery negative electrode interface; the output port of the power module is connected to the VIN interface of each battery active balancing module, the negative input port of the power module, the negative input port of the automatic switch module and the ground interface of the battery active balancing module are connected and grounded, and the switch port of the power module is connected to the switch port of the automatic switch module.

[0022] In a second aspect, the present invention provides an active equalization device for a lithium battery, wherein the active equalization device is prepared by the method for preparing an active equalization device for a lithium battery as described in the first aspect.

[0023] The present invention realizes constant current and constant voltage active balancing by adopting a lithium battery charging management chip, rather than pulse active balancing. The present invention has low cost and a simple structure compared with pulse active balancing. The isolated power supply module realizes protection of the lithium battery and provides working power for the battery active balancing module. The automatic switch module controls whether the power supply module supplies power to the battery active balancing module, thereby realizing automatic control of whether the battery active balancing module is turned on. The present invention prepares the battery active balancing module, the power supply module and the automatic switch module separately, and then connects and integrates them with wires. Such a design makes the preparation efficient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A flow chart of a method for preparing an active equalization device for a lithium battery;

[0026] Figure 2 It is a connection diagram of the active equalization device;

[0027] Figure 3 is a circuit diagram of a power module;

[0028] Figure 4 This is a circuit diagram of a battery active balancing module;

[0029] Figure 5 This is a circuit diagram of the automatic switch module.

[0030] Among them, 10, battery active balancing module, 11, isolation power module, 12, lithium battery charging management chip, 20, power module, 30, automatic switch module. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0033] It should be noted that the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0034] The present application provides a method for preparing a lithium battery active equalization device, see Figure 1 ,include:

[0035] A battery active balancing module 10 for actively balancing a battery pack is prepared, wherein the battery active balancing module 10 includes an isolation power module 11 and a lithium battery charging management chip 12;

[0036] Prepare a power module 20 for supplying power to the battery active balancing module 10;

[0037] An automatic switch module 30 is prepared for automatically controlling whether the power module 20 supplies power to the battery active balancing module 10;

[0038] The power module 20 and the automatic switch module 30 are connected by a wire, and the power module 20 and the battery active balancing module 10 are connected by a wire to obtain an active balancing device.

[0039] It can be understood that the battery active balancing module 10 is used to start the active balancing function when the power supply of the power module 20 is obtained, and to turn off the active balancing function when the power supply of the power module 20 is lost.

[0040] It can be understood that the wire connection is to achieve electrical connection. In one embodiment, the wire connection between the power module 20 and the automatic switch module 30 is not only the wire connected between the power module 20 circuit board and the automatic switch module 30 circuit board, but also includes the wire in the power module 20 circuit board and the wire in the automatic switch module 30 circuit board. Similarly, the power module 20 and the battery active balancing module 10 can be connected. In another embodiment, the battery active balancing module 10, the power module 20 and the automatic switch module 30 can be integrated into a circuit module at the same time, and the modules are connected by PCB copper wires.

[0041] It should be understood that the specific steps prepared in the above method may vary according to different execution processes, so the above method does not represent or imply that all steps must be performed in this order. A person skilled in the art can transform or change the execution order of the above steps based on the present invention, for example, prepare a battery active balancing module, a power module and an automatic switch module at the same time.

[0042] In this embodiment, the number of the active battery balancing modules 10 is the same as the number of the battery groups, and they are arranged in a one-to-one correspondence. One active battery balancing module 10 is used to actively balance the battery group uniquely corresponding to it.

[0043] The battery pack includes a cell, the battery pack is one cell (the number of cell is only 1), or the battery pack is a parallel cell (that is, the lithium battery pack includes a plurality of branches, each branch has a plurality of cell, and it is not limited whether the number of cell on different branches is the same. It can be understood that the number of branches is at least 2), and the cell is a lithium cell.

[0044] Here, the number of battery cells included in different lithium ion battery packs is not required to be the same, and can be set according to the needs of actual applications.

[0045] In this field, a battery pack is generally composed of multiple battery packs (connected in series), and a battery management system is also added, which is the product that the battery factory finally supplies to users. The number of battery active balancing modules 10 is not limited, and can be set according to the number of battery packs that need to be balanced. This embodiment is suitable for active balancing of multiple battery packs.

[0046] In this embodiment, the lithium battery active equalization device prepared by the above method includes a plurality of battery active equalization modules 10 , an automatic switch module 30 , and a power module 20 or a plurality of power modules 20 .

[0047] See also Figure 2The battery active balancing module 10 includes a VIN interface, a ground (GND) interface, a lithium battery positive electrode (B+) interface, and a lithium battery negative electrode (B-) interface. The power module 20 includes an output port (OUT), a switch port (ON\OFF), a positive input port (VIN+), and a negative input port (VIN-). The automatic switch module 30 includes a switch port (ON\OFF), a positive input port (VIN+), and a negative input port (VIN-).

[0048] For the purpose of name distinction, the switch port (ON\OFF) of the power module 20 can be called the first switch port, the positive input port (VIN+) can be called the first positive input port, and the negative input port (VIN-) can be called the first positive input port; the switch port (ON\OFF) of the automatic switch module 30 can be called the second switch port, the positive input port (VIN+) can be called the second positive input port, and the negative input port (VIN-) can be called the second negative input port.

[0049] The wire connection relationship is as follows: the switch port of the automatic switch module 30 is connected to the switch port of the power module 20, and the opening signal and the closing signal are transmitted through the two switch ports, so that the automatic switch module 30 controls the opening and closing of the battery active balancing module 10 by determining whether the power module 20 supplies power to the battery active balancing module 10.

[0050] The output port (OUT) of the power module 20 is connected to the VIN interface of each active battery balancing module 10. The negative input port of the power module 20, the negative input port of the automatic switch module 30 and the ground interface of the active battery balancing module 10 are connected together and grounded.

[0051] The positive input port of the power module 20 is connected to the positive electrode (BAT+) of the first battery group or the positive electrode (PACK+) of the first battery pack, and the negative input port of the power module 20 is connected to the negative electrode (BAT-) of the first battery group or the negative electrode (PACK-) of the first battery pack; the positive input port of the automatic switch module 30 is connected to the positive electrode (BAT+) of the first battery group or the positive electrode (PACK+) of the first battery pack, and the negative input port of the automatic switch module 30 is connected to the negative electrode (BAT-) of the first battery group or the negative electrode (PACK-) of the first battery pack. The first battery group is composed of battery groups actively balanced by all battery active balancing modules 10, and the first battery pack is composed of battery groups actively balanced by all battery active balancing modules 10 and a battery management system.

[0052] The positive electrode (B+) interface of the lithium battery of the active battery balancing module 10 is connected to the positive electrode of the battery pack, and the negative electrode (B-) interface of the lithium battery of the active battery balancing module 10 is connected to the negative electrode of the battery pack. As an embodiment, there are 4 battery packs in total, and there are 4 active battery balancing modules 10 corresponding to each other.

[0053] The power module 20 can obtain a switch signal from the automatic switch module 30 (through two switch ports). The power module 20 controls the power supply to the battery active balancing module 10 according to the switch signal sent thereto by the automatic switch module 30 , that is, controls the operation of the power module 20 .

[0054] In this embodiment, the automatic switch module 30 is also connected to the first battery group or the first battery pack by a wire, and is used to obtain the voltage of the first battery group or the first battery pack and determine whether the power module 20 supplies power to the battery active balancing module 10 accordingly. Specifically, the automatic switch module 30 sets a threshold for the open signal and a threshold for the close signal. When the voltage of the first battery group or the first battery pack reaches the corresponding threshold, the open signal or the close signal is obtained and sent to the power module 20, and the power module 20 supplies power to the battery active balancing module 10 or does not supply power to the battery active balancing module 10 accordingly.

[0055] In other embodiments, the battery active balancing module 10 includes an active balancing unit and a monitoring unit. The power module 20 supplies power to the active balancing unit and the monitoring unit of the battery active balancing module 10. The active balancing unit is used to control the voltage difference of the battery cells in the battery pack within a certain range during the charging and discharging process, so as to achieve the purpose of balancing the battery cells in the battery pack and thus prolonging the life of the battery pack. The monitoring unit of the battery active balancing module 10 can continuously monitor the real-time data of the battery pack (including voltage data and balancing current data); the automatic switch module 30 can monitor the voltage data of the first battery pack or the first battery pack in real time, and analyze and compare it with the set balancing threshold value to obtain an opening signal or a closing signal, and send the opening signal and the closing signal to the power module 20. The power module 20 receives and controls whether to supply power to the active balancing unit accordingly. If it is powered, the active balancing unit performs active balancing.

[0056] The circuits and preparations of the battery active balancing module 10 , the power module 20 , and the automatic switch module 30 are described in detail below.

[0057] The power module 20 includes a switching power chip. Preferably, the conversion efficiency of the switching power chip is greater than 90%, and the switching power chip has a shutdown control pin or an undervoltage protection function.

[0058] The power module 20 includes any one or more combinations of synchronous switching power chips and asynchronous switching power chips. Preferably, the power module 20 only includes synchronous switching power chips.

[0059] Specifically, the power module 20 also includes a number of power inductors, a number of peripheral devices of a switching power chip, a number of resistors, a number of capacitors, and a number of diodes.

[0060] The preparation process of the power module 20 is as follows: according to the number of balanced battery groups (for example Figure 2 As shown, a lithium battery active balancing device balances 4 battery packs in total, then the number of battery packs is 4, the number of battery packs can be called the number of battery cell strings), input voltage, input power, output voltage, output power, conversion efficiency, select switching power supply chips, power inductors, capacitors (input capacitors, output capacitors), resistors, use EDA software to draw circuit schematics, draw PCBs, perform SMT patching, and obtain power module 20. It can be understood that the selection also includes selecting peripheral devices, resistors, diodes, etc.

[0061] See also Figure 3 In this embodiment, the circuit of the power module 20 is as follows: the switching power supply chip has at least 21 pins. The first pin is grounded through the capacitor C7, the twentieth pin is connected to one end of the capacitor C6, the eighteenth pin, the seventeenth pin and the nineteenth pin are all connected to the other end of the capacitor C6, the sixteenth pin and the fifteenth pin are all connected to the positive pole of the first diode and the positive pole of the second diode, the negative pole of the first diode, the negative pole of the second diode and the other end of the capacitor C6 are all connected to one end of the capacitor C8 and one end of the inductor L1, and the other end of the inductor L1 is connected to the positive pole of the polar capacitor C9, one end of the capacitor C10, one end of the resistor R6, and one end of the resistor R4. The other end of the capacitor C8 is connected to one end of the resistor R3, and the other end of the resistor R3, the negative pole of the polar capacitor C9, and the other end of the capacitor C10 are connected together and grounded. One end of the resistor R4 is connected to the twelfth pin. The other end of the inductor L1, the positive electrode of the polarized capacitor C9, one end of the capacitor C10, one end of the resistor R6, one end of the resistor R4 and the twelfth pin are connected to the output port (OUT) of the power module 20. The other end of the resistor R6 is connected to the positive electrode of the light-emitting diode D2, the other end of the resistor R4 is connected to one end of the resistor R5, the other end of the resistor R4 and one end of the resistor R5 are connected to the seventh pin, the seventh pin is also connected to one end of the capacitor C4, and the other end of the capacitor C4 is connected to the sixth pin through the resistor R1. The fourteenth pin, the thirteenth pin, the tenth pin and the twenty-first pin are connected and grounded. The ninth pin is connected to one end of the capacitor C5, the eighth pin is connected to one end of the resistor R2, and the other end of the capacitor C5 and the other end of the resistor R2 are connected and grounded. The fifth pin is not connected. The eleventh pin is grounded through the capacitor C3. The second pin is used as the switch port (ON\OFF) of the power module 20. The fourth pin and the third pin are simultaneously connected to one end of the capacitor C2, one end of the capacitor C1 and the positive input port (VIN+) of the power module 20. The other end of the capacitor C2 and the other end of the capacitor C1 serve as a negative input port (VIN-) of the power module 20 , and the other end of the capacitor C2 and the other end of the capacitor C1 are both grounded.

[0062] The battery active balancing module 10 includes an isolation power module 11 and a lithium battery charging management chip 12 .

[0063] The preparation process of the battery active balancing module 10 is as follows: setting the charging voltage and charging current for the lithium battery charging management chip 12, using EDA software to draw a circuit schematic, drawing a PCB, and performing SMT (surface mounting technology) patching to obtain the battery active balancing module 10.

[0064] Specifically, the battery active balancing module 10 further includes peripheral devices, capacitors, resistors, and diodes. It can be understood that the preparation process includes steps such as selecting resistors, capacitors, and diodes for the battery active balancing module 10.

[0065] See also Figure 4 , the isolated power module 11 (U5) is used to protect the battery pack and to provide power for the active battery balancing module 10. The isolated power module 11 (U5) is connected to the output port (OUT) of the power module 20, and the isolated power module 11 (U5) provides working power for the active balancing module 10. Preferably, a high-efficiency isolated power module 11 with short-circuit protection function is selected. The output end +VO of the isolated power module 11 (U5) is connected to one end of the capacitor C22 and one end of the capacitor C24, and the voltage port OV of the isolated power module 11 (U5) is connected to the other end of the capacitor C22 and the other end of the capacitor C24. The VIN interface of the active battery balancing module 10 is connected to the input end VIN of the isolated power module 11 (U5), one end of the capacitor C20 and one end of the capacitor C21, that is, the input end VIN of the isolated power module 11 (U5) is used as the VIN interface of the active battery balancing module 10, and the input end VIN of the isolated power module 11 (U5) is connected to one end of the capacitor C20 and one end of the capacitor C21. The ground terminal GND of the isolated power module 11 is connected to the other end of the capacitor C20 and the other end of the capacitor C21, and is grounded at the same time. The ground terminal GND of the isolated power module 11, the other end of the capacitor C20, and the other end of the capacitor C21 are grounded as the ground (GND) interface of the battery active balancing module 10.

[0066] The lithium battery charging management chip 12 (U6) is used to manage the charging of the battery pack, that is, to realize the active balancing function as an active balancing unit. The charging cut-off voltage and charging current are set in the lithium battery charging management chip 12. When the voltage of the battery cell is less than the charging cut-off voltage, the lithium battery charging management chip 12 manages the battery pack to charge with the set charging current. When the voltage of the lithium battery cell reaches the charging cut-off voltage, the lithium battery charging management chip 12 stops charging the battery cell. The lithium battery charging management chip 12 (U6) uses a high-precision single-string lithium battery management lithium battery charging management chip 12, which can only manage the charging of one battery pack. The lithium battery charging management chip 12 (U6) has 5 terminals, namely, an output terminal (CHRG terminal) for indicating the charging status, a ground terminal (GND terminal), a charging current outflow terminal (BAT terminal), a positive input power supply voltage terminal (VCC terminal), and a programming charging current input terminal (PROG terminal). The PROG terminal is used to realize the corresponding charging current setting, termination charging current setting, shutdown and other functions, and the BAT terminal monitors the battery cell voltage.

[0067] The voltage port OV of the isolated power module 11 (U5) is connected to the negative electrode (B-) interface of the lithium battery of the battery active balancing module 10. The VCC terminal of the lithium battery charging management chip 12 (U6) and one end of the resistor R21 are both connected to the fourth pin of U5 of the battery active balancing module 10 (the output terminal +VO of the isolated power module 11, outputting the isolated power supply VCC); one end of the resistor R20 is connected to the negative electrode (B-) interface of the lithium battery. The other end of the resistor R20 is connected to the PROG terminal of the lithium battery charging management chip 12 (U6). The other end of the resistor R21 is connected to the positive electrode of the light-emitting diode D6, and the negative electrode of the light-emitting diode D6 is connected to the CHRG terminal of the lithium battery charging management chip 12 (U6). The BAT terminal of the lithium battery charging management chip 12 (U6) is connected to one end of the capacitor C23, and serves as the positive electrode (B+) interface of the lithium battery of the battery active balancing module 10. The GND terminal of the lithium battery charging management chip 12 (U6) is connected to the other end of the capacitor C23, and the other end of the resistor R20 and the other end of the capacitor C23 are connected to the lithium battery negative electrode (B-) interface of the battery active balancing module 10. The lithium battery positive electrode (B+) interface is used to connect to the positive electrode of the battery pack, and the lithium battery negative electrode (B-) interface is used to connect to the negative electrode of the battery pack.

[0068] In this embodiment, the isolated power supply module 11 is a combination of one or more isolated power supplies, the isolated power supply module 11 is an integrated power supply, and the isolated power supply module 11 is composed of an isolated power supply and discrete devices. Discrete devices refer to devices that need to be separately (purchased and) connected in order to realize the application of isolated power supply to the active balancing device and realize its function, such as capacitors, resistors, power chips, etc. It is preferred that the isolated power supply module 11 only includes an integrated isolated power supply, and does not include discrete devices.

[0069] In this embodiment, the lithium battery charging management chip 12 is usually a directly purchased single-string lithium battery management lithium battery charging management chip 12, which can also be designed and manufactured.

[0070] The automatic switch module 30 includes an operational amplifier device or a comparator device. Preferably, the operational amplifier device is a low-power operational amplifier chip with an operating power consumption of less than 50 μA. The operational amplifier device is one or a combination of an integrated low-power operational amplifier chip (operational amplifier) ​​and a low-power comparator (voltage comparator).

[0071] The preparation process of the automatic switch module 30 is as follows: according to the number of balanced battery strings, the balanced start voltage threshold is selected, and an operational amplifier device or a comparator device is selected; the circuit schematic diagram of the automatic start-up balanced module is drawn using EDA software, the PCB is drawn, and SMT patch is performed to obtain the automatic start-up balanced module.

[0072] See also Figure 5 The automatic switch module 30 includes a power chip U3, an operational amplifier U2A, an operational amplifier U2B, an AND gate device U4, a resistor, etc. Preferably, the resistors in the automatic switch module 30 are all high-precision resistors with a resistance accuracy of 0.1%. Here, the accuracy of all resistors in the automatic switch module 30 is 0.1%.

[0073] The circuit of the automatic switch module 30 is as follows: V IN The first end is connected to one end of capacitor C13, one end of capacitor C16, the cathode of voltage zener diode D4, and one end of resistor R10. The other end of resistor R10 is connected to the cathode of diode D3. The anode of diode D3 is connected to the positive input port (VIN+) of automatic switch module 30, one end of capacitor C13, one end of capacitor C16, and VIN+ of power chip U3. OUT The first end is connected to one end of capacitor C17, one end of capacitor C18, and one end of magnetic bead FB1. The other end of magnetic bead FB1 is connected to the cathode of voltage-stabilizing diode D5 and one end of capacitor C19 to provide working power VCC (the working power is obtained by filtering the VOUT output of power chip U3 through capacitor C17, capacitor C18, magnetic bead FB1, and capacitor C19). The other end of capacitor C13, the other end of capacitor C16, the anode of voltage-stabilizing diode D4, the GND end of power chip U3, the other end of capacitor C17, the other end of capacitor C18, the anode of voltage-stabilizing diode D5 and the other end of capacitor C19 are connected, and all are connected to the negative input port (VIN-) of automatic switch module 30 and ground.

[0074] One input terminal IN1 of the AND gate device U4 is connected to the output terminal of the operational amplifier U2A, the other input terminal of the AND gate device U4 is connected to the output terminal of the operational amplifier U2B, the VCC terminal of the AND gate device U4 is connected to the corresponding working power supply VCC, the GND of the AND gate device U4 is grounded, the output terminal of the AND gate device U4 is connected to the resistor R19 and the switch port (ON\OFF) of the automatic switch module 30, that is, as the switch port of the automatic switch module 30, the other end of the resistor R19 is grounded. The reverse input terminal of the operational amplifier U2A is connected to the reference voltage VREF, the positive input terminal of the operational amplifier U2A is connected to one end of the capacitor C14 and one end of the resistor R17, the other end of the resistor R17 is connected to one end of the resistor R11 and one end of the resistor R12, the other end of the resistor R11 is connected to the positive input port (VIN+) of the automatic switch module 30, the other end of the resistor R12 is connected to one end of the resistor R13, the other end of the resistor R13 is connected to the other end of the capacitor C14 and grounded. The positive input terminal of the operational amplifier U2B is connected to the reference voltage VREF, the reverse input terminal of the operational amplifier U2B is connected to one end of the capacitor C15 and one end of the resistor R18, the other end of the resistor R18 is connected to one end of the resistor R15 and one end of the resistor R14, the other end of the resistor R14 is connected to the positive input port (VIN+) of the automatic switch module 30, the other end of the resistor R15 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to the other end of the capacitor C15 and is grounded.

[0075] The working power supply VCC is connected to the eighth pin of the operational amplifier U2C and one end of the capacitor C11, and the other end of the capacitor C12 and the fourth pin of the operational amplifier U2C are both grounded. The working power supply VCC is connected to one end of the resistor R7, the other end of the resistor R7 is connected to one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R9 is connected to one end of the capacitor C12 and the reference voltage VREF (VREF is obtained by dividing the working power supply VCC by the resistor R7 and the resistor R8, and then filtering by the resistor R9 and the capacitor C12), and the other end of the capacitor C12 is connected to the other end of the resistor R8 and grounded.

[0076] The present embodiment is a lithium battery active equalization device and a preparation method thereof, which adopts a lithium battery charging management chip 12. The charging process of the lithium battery charging management chip 12 includes three stages: pre-charging, constant current charging and constant voltage charging. The lithium battery charging management chip 12 is used to realize constant current and constant voltage active equalization, rather than pulse current active equalization. The lithium battery charging management chip 12 is used to make the present embodiment simpler than the structure of pulse current active equalization; the isolation power module 11 is used to realize the protection of the battery pack and provide working power for the battery active equalization module 10; the automatic switch module 30 is used to control whether the power module 20 supplies power to the battery active equalization module 10, thereby realizing automatic control of whether the battery active equalization module 10 is turned on. The cost of the constant current active equalization device is low. The battery active equalization module 10 with the isolation power module 11 and the lithium battery charging management chip 12 makes the cost of the active equalization device low. The battery active equalization module 10, the power module 20 and the automatic switch module 30 are prepared separately first, and then connected and integrated with wires (including PCB board copper wires or wires), so that the preparation is efficient and fast.

[0077] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concept is known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing an active equalization device for a lithium battery, characterized in that: include: Prepare a battery active balancing module for actively balancing a battery pack, wherein the battery active balancing module includes an isolation power module and a lithium battery charging management chip; Prepare a power module for supplying power to the battery active balancing module; Prepare an automatic switch module for automatically controlling whether the power module supplies power to the battery active balancing module; The wire connects the power module and the automatic switch module, and the wire connects the power module and the battery active balancing module to obtain an active balancing device.

2. The method for preparing an active equalization device for a lithium battery according to claim 1, characterized in that: The preparation of the battery active balancing module for actively balancing the battery pack specifically comprises: setting the charging voltage and charging current for the lithium battery charging management chip, using EDA software to draw the circuit schematic diagram of the battery active balancing module, drawing the PCB, performing SMT patching, and obtaining the battery active balancing module.

3. The method for preparing an active equalization device for a lithium battery according to claim 1, characterized in that: The isolated power supply module has a short circuit protection function, and the lithium battery charging management chip is a lithium battery charging management chip for a single string of lithium batteries.

4. The method for preparing an active equalization device for a lithium battery as claimed in claim 1, characterized in that: The automatic switch module includes an operational amplifier device or a comparator device. The specific preparation process of the automatic switch module is: according to the number of balanced battery groups, a balanced start voltage threshold is selected, and an operational amplifier device or a comparator device is selected; using EDA software to draw a circuit schematic diagram of the automatic start-up balanced module, draw a PCB, and perform SMT patching to obtain the automatic start-up balanced module.

5. The method for preparing an active equalization device for a lithium battery as claimed in claim 4, characterized in that: The operating power consumption of the operational amplifier device is less than 50 μA.

6. The method for preparing an active equalization device for a lithium battery as claimed in claim 1, characterized in that: The automatic switch module includes resistors, and the accuracy of all resistors in the automatic switch module is 0.1%.

7. The method for preparing an active equalization device for a lithium battery as claimed in claim 1, characterized in that: The power module includes a switching power chip, a power inductor, a capacitor and a resistor; the preparation process of the power module is specifically as follows: according to the number of balanced battery cell strings, input voltage, input power, output voltage, output power and conversion efficiency, a switching power chip, a power inductor, a capacitor and a resistor are selected, a circuit schematic is drawn using EDA software, a PCB is drawn, and SMT patch is performed to obtain a power module.

8. The method for preparing an active equalization device for a lithium battery as claimed in claim 7, characterized in that: The switching power supply chip conversion efficiency is greater than 90%.

9. The method for preparing an active equalization device for a lithium battery as claimed in claim 1, characterized in that: The battery active balancing module includes a VIN interface, a ground interface, a lithium battery positive electrode interface and a lithium battery negative electrode interface; the power module includes an output port, a switch port, a positive input port and a negative input port; the automatic switch module includes a switch port, a positive input port and a negative input port; the battery active balancing module includes a VIN interface, a ground interface, a lithium battery positive electrode interface and a lithium battery negative electrode interface; the output port of the power module is connected to the VIN interface of each battery active balancing module, the negative input port of the power module, the negative input port of the automatic switch module and the ground interface of the battery active balancing module are connected and grounded, and the switch port of the power module is connected to the switch port of the automatic switch module.

10. An active equalization device for a lithium battery, characterized in that: The active equalization device is prepared by the method for preparing an active equalization device for a lithium battery according to any one of claims 1 to 9.

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