A lithium battery bms active balancing system and a balancing method thereof

Abstract

This invention discloses a lithium battery BMS active balancing system, including a lithium battery power supply module, a lithium battery balancing module, a control management box, and an integrated box for the power supply circuit and the balancing energy circuit. The lithium battery power supply module includes a type A lithium battery pack and a type B lithium battery pack. The lithium battery balancing module includes two balancing lithium batteries. The control management box contains a microcontroller and a BMS communication module. The integrated box for the power supply circuit and the balancing energy circuit has upper and lower layered boards. The upper layer of the integrated box contains the power supply circuit, and the lower layer contains the balancing and charging circuit. The method steps are as follows: two sets of type A lithium battery packs and one set of type B lithium battery packs are used for power balancing and replacement; the balancing batteries are then charged for balancing. This invention can accurately determine the battery charge and power demand, ensuring rapid balancing and charging of low-charge lithium batteries to replace them with new low-charge lithium batteries for power supply. The balancing and charging replacement speed is fast, ensuring balancing and charging efficiency.

Description

Technical Field

[0001] This invention relates to the field of lithium battery balancing technology, and in particular to a lithium battery BMS active balancing system and balancing method. Background Technology

[0002] Currently, there are three main types of active balancing solutions for lithium batteries on the market: capacitive balancing, inductive balancing, and transformer balancing. All three methods can achieve balancing during charging and during resting, but they all involve "shaving high-capacity cells and filling low-capacity cells": that is, transferring charge from high-capacity cells to low-capacity cells through external circuitry to achieve uniform charge levels. The drawbacks of these balancing solutions are as follows: 1. Capacitive and inductive balancing can only achieve energy transfer between adjacent cells: when only a few cells in the battery pack have excessively high or low capacity, the capacity of all cells needs to be adjusted, resulting in low balancing efficiency. 2. Transformer balancing can achieve energy transfer between non-adjacent cells, but extracting energy from high-capacity cells is equivalent to extra discharge from those cells, increasing their relative aging rate and accelerating their cycle life. The balancing process suffers from significant energy loss, which is detrimental to lithium battery power supply. Furthermore, the balancing process cannot precisely determine a balancing scheme for each lithium battery; after balancing, the lithium battery power supply may still not meet the requirements, or the charge difference between lithium batteries may remain significant. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to propose a lithium battery BMS active balancing system and its balancing method, which solves problems such as low balancing efficiency, high energy loss during the balancing process, and poor balancing performance.

[0004] According to the present invention, a lithium battery BMS active balancing system includes a lithium battery power supply module, a lithium battery balancing module, a control management box, and an integrated box for power supply circuit and balancing energy circuit.

[0005] The lithium battery power supply module includes two sets of type A lithium battery packs and one set of type B lithium battery packs. The number of lithium batteries in each type A and type B lithium battery packs is four and the lithium battery models are the same. The three sets of lithium battery packs are arranged in a row, and the tabs on the top of the lithium batteries are arranged on the same straight line near the right side. The two positive and negative tabs on the top of each lithium battery have the same structure. The tabs include tab posts, upper outer extension copper busbars and lower outer extension copper busbars.

[0006] The lithium battery balancing module includes two balancing lithium batteries, and each of the two balancing lithium batteries has two balancing power supply tabs on the top right side.

[0007] The control management box contains a microcontroller and a BMS communication module, and the microcontroller is electrically connected to the BMS communication module.

[0008] The integrated box of the power supply circuit and the energy balancing circuit is provided with upper and lower layered boards. The upper layer of the integrated box of the power supply circuit and the energy balancing circuit contains the power supply circuit, and the lower layer contains the balancing and charging circuit.

[0009] The power supply circuit includes two power supply wires, multiple first electronically controlled double-switch and multiple first electronically controlled single-switch. The two power supply wires are arranged in parallel and connected at the same end with a wire, and the other end is the output end. The first power supply wire is parallel to the tabs on the top of all lithium batteries that are in a straight line. The upper outer copper busbars on the positive and negative tabs of each lithium battery are respectively connected to two interfaces of the input end of a first electronically controlled double-switch. The two output wires of the output end of the first electronically controlled double-switch are connected to two points on the first power supply wire, and the power supply wire between these two points is connected to a first electronically controlled single-switch.

[0010] The equalization and charging circuit includes an input equalization circuit and three identical output equalization circuits. The input equalization circuit includes a DC / AC converter, a loop wire, and three sets of transformer positive windings. The two output ports of the DC / AC converter are electrically connected by the two ends of the loop wire. Three electronically controlled equalization start switches are evenly spaced on the loop wire. At each position of an electronically controlled equalization start switch, a transformer positive winding is connected in parallel on both sides of the switch. An electronically controlled series start switch is located at the input end of each transformer positive winding. Two external charging wires are connected to the loop wire at the output position of the DC / AC converter. The output equalization circuit includes an AC / DC converter, a transformer secondary winding, and four second electronically controlled double-switch switches. The AC / DC converter has a transformer secondary winding and an extension wire connected to its two input terminals respectively. The transformer secondary winding is parallel to a corresponding transformer positive winding. The transformer secondary winding has a switching wire electrically connected to the extension wire at the middle and end positions respectively. Both switching wires are equipped with a first voltage conversion electronically controlled single-switch and a second voltage conversion electronically controlled single-switch. The AC / DC converter output terminal will have two equalization wires. The input terminals of four second electronically controlled double-switch switches are connected in series on the two equalization wires. Each output equalization circuit corresponds to a set of lithium battery packs. The output terminals of the four second electronically controlled double-switch switches on the output equalization circuit are electrically connected to the lower outer extension copper busbars of the four lithium batteries in the set of lithium battery packs respectively.

[0011] Each of the two equalizing power supply tabs on the top of the two equalizing lithium batteries has a charging wire. One of the equalizing lithium batteries has a first charging switch on the two charging wires on the two equalizing power supply tabs on the top of the two equalizing lithium batteries. The other equalizing lithium battery has a second charging switch on the two charging wires on the two equalizing power supply tabs on the top of the two equalizing lithium batteries. A third charging switch is provided on the wires that are electrically connected between the two closest positive equalizing power supply tabs and the negative equalizing power supply tabs on the top of the two equalizing lithium batteries. The charging wires on the two equalizing power supply tabs on the top of the two equalizing lithium batteries are connected to the input terminal of the DC / AC converter.

[0012] The BMS communication module is used to acquire the voltage and power information of each lithium battery in the three groups of lithium batteries. The microcontroller is used to control all the electronically controlled double-switch and electronically controlled single-switch on the power supply circuit, the equalization and charging circuit, and the equalization lithium battery output circuit.

[0013] In some embodiments of the present invention, the two sets of type A lithium battery packs are priority power supply lithium battery packs, and the type B lithium battery packs are equalization replacement lithium battery packs. When the power supply voltage requirement is met, it is necessary to ensure that the capacity of each lithium battery is above 50% and at least eight lithium batteries are required.

[0014] In other embodiments of the present invention, the two balanced lithium batteries are of the same type, and the capacity of the balanced lithium battery is 2-3 times that of a single lithium battery.

[0015] In other embodiments of the present invention, an insulating pad is inserted between the lithium battery power supply module and the lithium battery balancing module and the control management box, and an insulating pad is also inserted between the top of the lithium battery balancing module and the control management box and the integrated box of the balancing energy circuit.

[0016] A lithium battery BMS active balancing method is provided, which uses the aforementioned lithium battery BMS active balancing system to achieve balancing. The specific balancing steps are as follows:

[0017] S1: When both sets of Type A lithium battery packs and one set of Type B lithium battery packs are fully charged, the two sets of Type A lithium battery packs are prioritized for power supply. The first electronically controlled double-switch corresponding to the extended copper busbars on the eight lithium batteries in the two sets of Type A lithium battery packs is closed and connected, and the first electronically controlled single-switch connected in parallel with these eight first electronically controlled double-switch switches is opened. The first electronically controlled double-switch corresponding to the extended copper busbars on the four lithium batteries in the Type B lithium battery pack is opened, and the first electronically controlled single-switch connected in parallel with these four first electronically controlled double-switch switches is opened. When the single-switch is turned off and on, the lithium batteries in the eight type A lithium battery packs will continuously consume power during the power supply process. When the average charge of the eight lithium batteries in the type A lithium battery packs is lower than 80% of the average charge of the four lithium batteries in the type B lithium battery packs, the power supply to the four lithium batteries with the lowest charge in the type A lithium battery packs will be disconnected through the BMS communication module, and the replacement mode will be started to replace the power supply of the four lithium batteries in the type B lithium battery packs.

[0018] S2: After the replacement mode is performed in step S1, the four lithium batteries in the working A-type lithium battery pack continue to work until the average charge of these four lithium batteries is less than 60%. Then, the second replacement mode will be performed, and the four lithium batteries in the A-type lithium battery pack that were replaced in the first replacement will continue to provide power. Subsequent replacement modes will no longer distinguish between A-type and B-type lithium battery packs, and will replace the four lithium batteries with the lowest charge among the eight working lithium batteries.

[0019] S3: If multiple replacements are performed after step S2, and the power supply voltage is low due to the low power of eight lithium batteries, the starting block or a block of lithium batteries will be connected in series to supply power so that the power supply voltage reaches the required level. At this time, the remaining two or three lithium batteries will start active equalization charging.

[0020] S4: In step S3, active equalization charging starts by activating one of the two equalization lithium batteries to supply power or the two batteries are connected in series to supply power. When the equalization lithium battery is supplying power, the DC power is converted into AC power by the DC / AC converter and circulates in the loop conductor. When the remaining two or three lithium batteries are in the A-type lithium battery pack or B-type lithium battery pack, the electronically controlled equalization start switch connected in parallel to the positive winding position of the transformer of the A-type lithium battery pack or B-type lithium battery pack is opened. At the same time, the electronically controlled series start switch on the positive winding of the transformer is closed. The electronically controlled equalization start switch that is not connected in parallel to the positive winding position of the transformer is closed, and its corresponding electronically controlled series start switch is opened. If the positive winding of the transformer is energized, it will provide interactive magnetic field lines to the corresponding secondary winding of the transformer, and the secondary winding of the transformer will generate AC power. The AC power generated by the secondary winding of the transformer is converted into DC power by the AC / DC converter. When a lithium battery needs equalization charging, the second electronically controlled double-switch connected to it is closed and then turned on to perform equalization charging on its lithium battery.

[0021] S5: In step S4, the average charge level of the lithium batteries undergoing equalization charging is M1. Among the lithium batteries currently supplying power, the lowest charge level is selected, which is the same number as the lithium batteries undergoing equalization charging. The average charge level of the lowest charge level lithium batteries is calculated as M2. If the charge level of M1 is 20% higher than that of M2, a replacement mode will be activated. The equalization charging of the lithium batteries undergoing equalization charging will be cut off, and the lowest charge level lithium batteries will be replaced. The replaced lowest charge level lithium batteries will then start equalization charging. This step S5 is repeated cyclically to achieve equalization power supply to the entire lithium battery.

[0022] In other embodiments of the present invention, if there are no lithium batteries with a charge of more than 95% when the two sets of type A lithium battery packs and one set of type B lithium battery packs are started to supply power, the two sets of type A lithium battery packs are not started to supply power first. Instead, the power supply is supplied according to the mode after the second replacement mode in step S2. The subsequent power supply balancing mode is the same as in steps S3-S5.

[0023] In other embodiments of the present invention, if all lithium batteries have a charge level below 40%, the lithium batteries that are being balanced need to be quickly charged to complete the replacement mode replacement frequency. At this time, two balancing lithium batteries are connected in series to provide a larger voltage for balancing charging. When the balancing lithium batteries are connected in series, the transformer secondary winding will start the entire transformer secondary winding to receive the interactive magnetic field lines emitted by the transformer positive winding, thereby obtaining a larger voltage and current for balancing charging and improving the charging speed.

[0024] In other embodiments of the present invention, if a group of lithium batteries is supplying power and one or more of them have a discharge rate significantly higher than the other lithium batteries that are supplying power, the batteries with the significantly higher discharge rate will be de-supplyed and marked, and equalization charging will no longer be performed. At the same time, the spare lithium batteries will be replaced to supply power according to the number of batteries. If the number of batteries with significantly higher discharge rates is greater than or equal to four, the batteries with significantly higher discharge rates will not be de-supplyed, but they will still be marked.

[0025] In other embodiments of the present invention, if the lithium battery charge in both sets of type A lithium battery packs and one set of type B lithium battery packs is below 20%, the equalization charging of the empty batteries cannot be initiated. In this case, the lithium battery supplying power is initiated to perform synchronous equalization charging.

[0026] In this invention, spare lithium batteries are used to replace those with low charge levels in the working lithium battery system to achieve balanced power supply. This reduces the large power loss and poor power supply of traditional balanced power supply. Two balanced lithium batteries are used to charge all low-charge lithium batteries (less than 50% charge) in a balanced manner. The batteries that are supplying power are supplying power, while the batteries that are not supplying power are charging. This prevents the low-charge lithium batteries from having large differences in charge levels or even being unable to supply power, which would result in a low overall power supply voltage and fail to meet the power supply requirements.

[0027] Balanced power supply can ensure that the power difference of all low-power lithium batteries is reduced and that they can all be supplied with power, so as to make the most of the remaining low power.

[0028] It can accurately determine the battery level and power demand, ensuring rapid and balanced charging of low-power lithium batteries to replace them with new low-power lithium batteries for power supply. The balanced charging replacement speed is fast and ensures balanced charging efficiency. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 This is a schematic diagram of the active balancing system structure of a lithium battery BMS proposed in this invention.

[0031] Figure 2 This is a schematic diagram of the structure of a lithium battery BMS active balancing system proposed in this invention (with the integrated box containing the power supply circuit and the energy balancing circuit removed).

[0032] Figure 3 This is a schematic diagram of the structure of the lithium battery module proposed in this invention.

[0033] Figure 4 This is a schematic diagram of the structure of a single lithium battery proposed in this invention.

[0034] Figure 5 This is a schematic diagram of the power supply circuit proposed in this invention.

[0035] Figure 6 This is a schematic diagram of the equalization and charging circuit proposed in this invention.

[0036] In the diagram: 1. Lithium battery; 2. Balancing lithium battery; 21. Balancing power supply tab; 211. First charging single-switch switch; 212. Second charging single-switch switch; 213. Third charging single-switch switch; 3. Control management box; 4. Integrated box for power supply circuit and balancing energy circuit; 5. Tab; 51. Upper outer extension copper busbar; 511. First electronically controlled double-switch switch; 512. First electronically controlled single-switch switch; 52. Lower outer extension copper busbar; 521. Second electronically controlled double-switch switch; 6. First electronically controlled double-switch switch; 61. Transformer positive winding; 611. Electronically controlled series start switch; 612. Electronically controlled balancing start switch; 7. AC / DC converter; 8. Transformer secondary winding; 81. First voltage conversion electronically controlled single-switch switch; 82. Second voltage conversion electronically controlled single-switch switch; 9. DC / AC converter; 10. Insulating pad. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0038] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0039] Reference Figure 1-6 A lithium battery BMS active balancing system includes a lithium battery power supply module, a lithium battery balancing module, a control management box 3, and an integrated box 4 for the power supply circuit and the balancing energy circuit.

[0040] The lithium battery power supply module includes two sets of type A lithium battery packs and one set of type B lithium battery packs. The number of lithium batteries 1 in each of the type A and type B lithium battery packs is four and the lithium battery 1 model is the same. The three sets of lithium battery packs are arranged in a row, and the tabs 5 on the top of each lithium battery 1 are arranged on the same straight line near the right side. The two positive and negative tabs on the top of each lithium battery 1 have the same structure. The tabs include tab posts, upper outer extension copper busbars 51 and lower outer extension copper busbars 52.

[0041] The A-type lithium battery pack has the same structure as the B-type lithium battery pack. Alternatively, the B-type lithium battery pack can be configured as two for replacement and balancing based on the performance of lithium battery 1.

[0042] The lithium battery balancing module includes two balancing lithium batteries 2, and each of the two balancing lithium batteries 2 has two balancing electrode tabs 21 on the top right side.

[0043] The control and management box 3 is equipped with a microcontroller (MCU) and a BMS communication module. The microcontroller is electrically connected to the BMS communication module. BMS communication refers to the communication between the Battery Management System (BMS) and other systems or devices, which is the process of data transmission and interaction between the BMS and other systems or devices.

[0044] The integrated box 4 containing the power supply circuit and the energy balancing circuit has upper and lower layered boards. The upper layer of the integrated box 4 contains the power supply circuit, and the lower layer contains the balancing and charging circuit; the two layers do not interfere with each other.

[0045] The power supply circuit includes two power supply wires, multiple first electronically controlled double-switch 511s and multiple first electronically controlled single-switch 512s. The two power supply wires are arranged in parallel and connected at the same end with a wire, and the other end is the output end. The first power supply wire is parallel to the tabs 5 on the top of all lithium batteries 1 that are in a straight line. The upper outer copper busbar 51 on the positive and negative tabs of each lithium battery 1 is respectively connected to two interfaces of the input end of a first electronically controlled double-switch 511. The two output wires of the output end of the first electronically controlled double-switch 511 are connected to two points on the first power supply wire, and the power supply wire between these two points is connected to a first electronically controlled single-switch 512. The first electronically controlled double-switch 511 and the first electronically controlled single-switch 512 switch whether the lithium battery 1 is connected in series for power supply.

[0046] The equalization and charging circuit includes an input equalization circuit and three identical output equalization circuits. The input equalization circuit includes a DC / AC converter 9, a loop wire 6, and three sets of transformer positive windings 61. The two output ports of the DC / AC converter 9 are electrically connected by the two ends of the loop wire 6. Three electrically controlled equalization start switches 612 are evenly spaced on the loop wire 6. A transformer positive winding 61 is connected in parallel on both sides of each electrically controlled equalization start switch 612 on the loop wire 6. An electrically controlled series start switch 611 is provided at the input end of each transformer positive winding 61. Two external charging wires are connected to the output of the DC / AC converter 9 via the loop wire 6. The output equalization circuit includes an AC / DC converter 7, a transformer secondary winding 8, and four second electrically controlled double-switch 5. 21. The two input terminals of the AC / DC converter 7 are respectively connected to a transformer secondary winding 8 and an extension wire. The transformer secondary winding 8 is parallel to a corresponding transformer positive winding 61. The transformer secondary winding 8 is provided with a switching wire electrically connected to the extension wire at the middle position and the tail position. Both switching wires are provided with a first voltage conversion electronically controlled single-switch 81 and a second voltage conversion electronically controlled single-switch 82. The output terminal of the AC / DC converter 7 will be provided with two equalization wires. The input terminals of four second electronically controlled double-switch 521s are connected in series on the two equalization wires. Each output equalization circuit corresponds to a set of lithium battery packs. The output terminals of the four second electronically controlled double-switch 521s on the output equalization circuit are respectively electrically connected to the lower outer extension copper busbar 52 on the four lithium batteries 1 in the set of lithium battery packs.

[0047] DC / AC converter 9 is a DC to AC converter, while AC / DC converter 7 is an AC to DC converter.

[0048] Each of the two equalizing power supply tabs 21 on the top of the two equalizing lithium batteries 2 has a charging wire. The two charging wires on the two equalizing power supply tabs on the top of one of the equalizing lithium batteries 2 are equipped with a first charging switch 211, and the two charging wires on the two equalizing power supply tabs 21 on the top of the other equalizing lithium battery 2 are equipped with a second charging switch 212. The wires that are electrically connected between the two closest positive equalizing power supply tabs 21 and negative equalizing power supply tabs 21 on the top of the two equalizing lithium batteries 2 are equipped with a third charging switch 213. The charging wires on the two equalizing power supply tabs 21 on the top of the two equalizing lithium batteries 2 are all connected to the input terminal of the DC / AC converter 9.

[0049] When the first equalizing lithium battery 2 is independently equalized, the first charging single-switch 211 is closed, while the second charging single-switch 212 and the third charging single-switch 213 are open. When the second equalizing lithium battery 2 is independently equalized, the second charging single-switch 212 is closed, while the first charging single-switch 211 and the third charging single-switch 213 are open. When connected in series, the third charging single-switch 213 between the two equalizing power supply electrodes 21 is closed, and the corresponding first charging single-switch 211 and second charging single-switch 212 on these two equalizing power supply electrodes 21 are open, while the other two first charging single-switch 211 and second charging single-switch 212 are closed.

[0050] The BMS communication module is used to acquire the voltage and power information of each lithium battery in the three groups of lithium batteries. The microcontroller is used to control all the electronically controlled double-switch and electronically controlled single-switch on the power supply circuit, the equalization and charging circuit, and the equalization lithium battery output circuit.

[0051] The two sets of Type A lithium battery packs are priority power supply lithium battery packs, and the Type B lithium battery packs are equalization replacement lithium battery packs. When the power supply voltage requirement is met, each lithium battery must have a charge level of over 50%, and at least eight lithium batteries are required. At least two sets of lithium battery packs are needed to supply power. This ensures that the number of lithium batteries not supplying power is relatively small, thus reducing the energy consumption of the vehicle.

[0052] The two equalizing lithium batteries 2 are of the same model, and the capacity of the equalizing lithium battery 2 is 2-3 times that of a single lithium battery 1. This ensures balanced charging and provides backup power. The two equalizing lithium batteries 2 can be charged using an independent charging system, or the DC / AC converter 9 can have a reverse conversion function, using two external charging wires for reverse charging.

[0053] An insulating pad 10 is placed between the lithium battery power supply module, the lithium battery balancing module, and the control management box 3. An insulating pad 10 is also placed between the top of the lithium battery balancing module and the control management box 3, and between the lithium battery balancing module and the integrated box 4 of the energy balancing circuit. This ensures the safety of the system.

[0054] A lithium battery BMS active balancing method is provided, which uses the aforementioned lithium battery BMS active balancing system to achieve balancing. The specific balancing steps are as follows:

[0055] S1: When both sets of Type A lithium battery packs and one set of Type B lithium battery packs are fully charged, the two sets of Type A lithium battery packs are prioritized for power supply. The first electronically controlled double-switch 511 corresponding to the extended copper busbars 51 on the eight lithium batteries in the two sets of Type A lithium battery packs is closed and connected, and the first electronically controlled single-switch 512 connected in parallel with these eight first electronically controlled double-switch 511s is opened. The first electronically controlled double-switch 511 corresponding to the extended copper busbars on the four lithium batteries 1 in the Type B lithium battery pack is opened and connected in parallel with these four first electronically controlled single-switch 511s. The first electronically controlled single-switch 512 will be closed and then connected. During the power supply process, the lithium batteries 1 in the eight type A lithium battery packs will continuously consume power. When the average charge of the eight lithium batteries 1 in the type A lithium battery pack is lower than 80% of the average charge of the four lithium batteries in the type B lithium battery pack, the power supply of the four lithium batteries 1 with the lowest charge in the type A lithium battery pack will be obtained through the BMS communication module. The power supply of the four lithium batteries 1 with the lowest charge in the type A lithium battery pack will be disconnected, and the replacement mode will be started to replace the power supply of the four lithium batteries 1 in the type B lithium battery pack.

[0056] S2: After the replacement mode is performed in step S1, the four lithium batteries 1 in the working A-type lithium battery pack continue to work until the average charge of these four lithium batteries is less than 60%. Then, the second replacement mode will be performed, and the four lithium batteries 1 in the A-type lithium battery pack that were replaced in the first time will continue to supply power. The subsequent replacement modes will no longer distinguish between A-type lithium battery packs and B-type lithium battery packs, and will replace the four lithium batteries with the lowest charge among the eight working lithium batteries.

[0057] S3: If multiple replacements are performed after step S2, and the power supply voltage is low due to the low power of eight lithium batteries, nine or ten lithium batteries will be connected in series to supply power so that the power supply voltage reaches the required level. At this time, the remaining two or three lithium batteries will start active equalization charging.

[0058] S4: In step S3, active equalization charging is initiated by starting one of the two equalization lithium batteries 2 to supply power, or by connecting the two batteries in series. When the equalization lithium battery 2 supplies power, the DC power is converted into AC power by the DC / AC converter 9 and circulates within the loop conductor 6. When the remaining two or three lithium batteries 1 are in the A-type or B-type lithium battery pack, the electrically controlled equalization start switch 612 connected in parallel at the position of the positive winding 61 of the transformer corresponding to the A-type or B-type lithium battery pack is opened. At the same time, the electrically controlled series start switch 61 on the positive winding 61 of the transformer is activated. 1. When the transformer is closed, the electronically controlled equalization start switch 612, which is not connected in parallel to the corresponding transformer positive winding 61, is in the closed state, and its corresponding electronically controlled series start switch 611 is open. If the transformer positive winding 61 is energized, it will provide interactive magnetic field lines to the corresponding transformer secondary winding 8, and the transformer secondary winding 8 will generate alternating current. The alternating current generated by the transformer secondary winding 8 is converted into direct current through the AC / DC converter 7. When a lithium battery 1 needs equalization charging, the second electronically controlled double-cut switch 521 connected to it is closed and then turned on to perform equalization charging on its lithium battery 1.

[0059] S5: In step S4, the average charge level of the lithium batteries undergoing equalization charging is M1. Among the lithium batteries currently being supplied with power, the lowest charge lithium battery 1 is selected, which is the same number as the lithium batteries undergoing equalization charging. The average charge level of the lowest charge lithium batteries is calculated as M2. If the charge level of M1 is 20% higher than that of M2, a replacement mode will be activated. The equalization charging of the lithium batteries 1 undergoing equalization charging will be cut off, and the lowest charge lithium batteries 1 will be replaced. The replaced lowest charge lithium batteries 1 will then start equalization charging. This step S5 is repeated in a cycle to achieve equalization power supply to the entire lithium battery.

[0060] To reduce the power difference between lithium batteries 1, you can adjust the replacement mode to activate when the difference is 10%, which will accurately replace batteries at 8% or 5%. The replacement mode is inconvenient; the balancing method mainly relies on alternating power supply among the 12 lithium batteries. Balancing charging is only activated when the battery level is below 50%, the power supply voltage is insufficient, or even when the battery level remains low after replacement, to ensure that each lithium battery 1 operates normally and does not become too low to supply power.

[0061] If, when two sets of type A lithium battery packs and one set of type B lithium battery packs are starting up to provide power, there is no lithium battery 1 with a charge of more than 95%, the two sets of type A lithium battery packs will not be started up first to provide power. Instead, power will be provided according to the mode after the second replacement mode in step S2. The subsequent power supply balancing mode is the same as in steps S3-S5.

[0062] When the battery is not fully charged at the beginning, the system prioritizes powering the highest-charged lithium battery based on the detected battery level, and then switches to a replacement mode. The system will cycle the power supply to the batteries in a certain way, so that the battery levels of the lithium batteries are kept to a small difference.

[0063] If all lithium batteries 1 have a charge level below 40%, the lithium batteries that are being balanced need to be quickly charged to complete the replacement frequency of the replacement mode. At this time, two balancing lithium batteries 2 are connected in series to provide a larger voltage for balanced charging. When the balancing lithium batteries 2 are connected in series, the transformer secondary winding 8 will start the entire transformer secondary winding 8 to receive the interactive magnetic field lines emitted by the transformer positive winding 61, so as to obtain a larger voltage and current for balanced charging and improve the charging speed.

[0064] When the battery level drops, only rapid equalization charging can replenish it to ensure that the lithium battery is not too low to provide power, unless both equalization lithium batteries are also low.

[0065] If a group of lithium batteries 1 is supplying power, and one or more of them have a significantly higher discharge rate than the other lithium batteries 1 that are supplying power, the batteries with the significantly higher discharge rate will be de-supplyed and marked, and equalization charging will no longer be performed. At the same time, the spare lithium batteries will be replaced according to the number of batteries. If the number of batteries with significantly higher discharge rates is greater than or equal to four, the batteries with significantly higher discharge rates will not be de-supplyed, but they will still be marked.

[0066] When there are many lithium batteries with abnormal power supply, the power supply can only be guaranteed temporarily and cannot be stopped. Otherwise, the battery will not be able to supply power and can be repaired or replaced later.

[0067] If the lithium battery charge levels in both A-type lithium battery packs and one B-type lithium battery pack are all below 20%, the equalization charging of the empty batteries cannot be initiated. In this case, the lithium battery supplying power will be activated for synchronous equalization charging.

[0068] When lithium battery 1 has a very low charge, if the equalization charging and replacement modes are switched, there may not be enough time to equalize the charge, and some lithium batteries may run out of power. In this case, equalization lithium battery 2 can be connected in parallel with lithium battery 1 to provide power. That is, during equalization charging, lithium battery 1 is also activated to provide power, thus ensuring normal power supply for driving.

[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A lithium battery BMS active balancing system, characterized in that: It includes a lithium battery power supply module, a lithium battery equalization module, a control management box (3), and an integrated box (4) for power supply circuit and equalization energy circuit. The lithium battery power supply module includes two sets of type A lithium battery packs and one set of type B lithium battery packs. The number of lithium batteries (1) in both the type A and type B lithium battery packs is four and the lithium battery (1) models are the same. The three sets of lithium battery packs are arranged in a row, and the tabs (5) on the top of the lithium battery (1) are set on the same straight line near the right side. The two positive and negative tabs on the top of each lithium battery (1) have the same structure. The tabs include tab posts, upper outer extension copper busbars (51) and lower outer extension copper busbars (52). The lithium battery balancing module includes two balancing lithium batteries (2), and each of the two balancing lithium batteries (2) has two balancing electrode tabs (21) on the top right side. The control management box (3) is equipped with a microcontroller and a BMS communication module, and the microcontroller is electrically connected to the BMS communication module; The integrated box (4) of the power supply circuit and the equalization energy circuit is provided with upper and lower layered boards. The upper layer of the integrated box (4) of the power supply circuit and the equalization energy circuit is provided with a power supply circuit, and the lower layer is provided with an equalization and charging circuit. The power supply circuit includes two power supply wires, multiple first electronically controlled double-switch (511) and multiple first electronically controlled single-switch (512). The two power supply wires are arranged in parallel and connected at the same end with a wire, and the other end is the output end. The first power supply wire is parallel to the tabs (5) on the top of all lithium batteries (1) that are in a straight line. The upper outer extension copper busbar (51) on the positive and negative tabs of each lithium battery (1) is respectively connected to the two interfaces of the input end of a first electronically controlled double-switch (511). The two output wires of the output end of the first electronically controlled double-switch (511) are connected to the two points of the first power supply wire, and the power supply wire between these two points is connected to the first electronically controlled single-switch (512). The equalization and charging circuit includes an input equalization circuit and three identical output equalization circuits. The input equalization circuit includes a DC / AC converter (9), a loop wire (6), and three sets of transformer positive windings (61). The two interfaces of the output terminal of the DC / AC converter (9) are electrically connected by the two ends of the loop wire (6). Three electrically controlled equalization start switches (612) are equally spaced on the loop wire (6). A transformer positive winding (61) is connected in parallel on both sides of the loop wire (6) at the position of each electrically controlled equalization start switch (612). An electrically controlled series start switch (611) is provided on the input terminal of the transformer positive winding (61). The loop wire (6) is connected in parallel with the DC / AC converter (9). Two external charging wires are connected to the output terminal of the converter (9). The output equalization circuit includes an AC / DC converter (7), a transformer secondary winding (8), and four second electronically controlled double-switch (521). The two input terminals of the AC / DC converter (7) are respectively connected to the transformer secondary winding (8) and an extension wire. The transformer secondary winding (8) is parallel to a corresponding transformer positive winding (61). The transformer secondary winding (8) is provided with a switching wire electrically connected to the extension wire at the middle position and the tail position. Each of the switching wires is provided with a first voltage conversion electronically controlled single-switch (81) and a second voltage conversion electronically controlled single-switch (82). The output terminal of the AC / DC converter (7) will be provided with two equalization wires. The input terminals of the four second electronically controlled double-switch (521) are connected in parallel on the two equalization wires. Each of the output equalization circuits corresponds to a set of lithium battery packs. The output terminals of the four second electronically controlled double-switch (521) on the output equalization circuit are respectively electrically connected to the lower outer extension copper busbar (52) on the four lithium batteries (1) in a set of lithium battery packs. Each of the two equalizing power supply tabs (21) on the top of the two equalizing lithium batteries (2) has a charging wire. The two charging wires on the two equalizing power supply tabs on the top of one of the equalizing lithium batteries (2) are provided with a first charging switch (211), and the two charging wires on the two equalizing power supply tabs (21) on the top of the other equalizing lithium battery (2) are provided with a second charging switch (212). The wires that are electrically connected between the two closest positive equalizing power supply tabs (21) and negative equalizing power supply tabs (21) on the top of the two equalizing lithium batteries (2) are provided with a third charging switch (213). The charging wires on the two equalizing power supply tabs (21) on the top of the two equalizing lithium batteries (2) are connected to the input terminal of the DC / AC converter (9). The BMS communication module is used to obtain the voltage and power information of each lithium battery in the three groups of lithium batteries. The microcontroller is used to control all the electronically controlled double-switch and electronically controlled single-switch on the power supply circuit, the equalization and charging circuit, and the equalization lithium battery output circuit. When fully charged, the system prioritizes power supply from the eight lithium batteries in the two Type A lithium battery packs. When their average charge level falls below 80% of the average charge level of the four lithium batteries in the Type B lithium battery pack, the four lithium batteries with the lowest charge level in the Type A pack are replaced, and the four lithium batteries in the Type B pack take over power supply. After the first replacement, if the remaining four working Type A lithium batteries have a charge level below 60%, the four Type A lithium batteries that were initially replaced are activated. Subsequent replacements do not distinguish between battery pack types; only the four lithium batteries with the lowest charge level among the currently working eight lithium batteries are replaced. After multiple replacements, if the low power supply voltage due to insufficient charge of the eight lithium batteries results in a low power supply voltage, the system will activate... Nine and ten lithium batteries are connected in series to provide power. The remaining two or three lithium batteries start active equalization charging. The power is supplied by the equalization lithium batteries. The DC power is converted to AC power by the DC / AC converter. The AC power is transmitted through the positive and negative windings of the transformer of the corresponding group. Then it is converted to DC power by the AC / DC converter. The second electronic control double switch controls the precise charging of the low-power lithium batteries. When the average power M1 of the equalization charging lithium batteries is 20% higher than the average power M2 of the currently lowest-power lithium battery, the charging of the former is cut off and the power supply is replaced. The original lowest-power lithium battery enters the equalization charging cycle to achieve overall equalization power supply.

2. The lithium battery BMS active balancing system according to claim 1, characterized in that: The two sets of A-type lithium battery packs are priority power supply lithium battery packs, and the B-type lithium battery packs are equalization replacement lithium battery packs. When the power supply voltage requirement is met, it is necessary to ensure that the power of each lithium battery (1) is above 50% and at least eight lithium batteries are required.

3. The lithium battery BMS active balancing system according to claim 1, characterized in that: The two balanced lithium batteries (2) are of the same model, and the capacity of the balanced lithium battery (2) is 2-3 times that of a lithium battery (1).

4. The lithium battery BMS active balancing system according to claim 1, characterized in that: An insulating pad (10) is placed between the lithium battery power supply module and the lithium battery equalization module and the control management box (3). An insulating pad (10) is also placed between the top of the lithium battery equalization module and the control management box (3) and the integrated box (4) of the equalization energy circuit.

5. A lithium battery BMS active balancing method, characterized in that: The lithium battery BMS active balancing system according to any one of claims 1-4 is used to achieve balancing, and the specific balancing steps are as follows: S1: When both sets of Type A lithium battery packs and one set of Type B lithium battery packs are fully charged, the two sets of Type A lithium battery packs are started first to provide power. The first electronically controlled double-switch (511) corresponding to the extended copper busbars (51) on the eight lithium batteries in the two sets of Type A lithium battery packs is closed and connected, and the first electronically controlled single-switch (512) connected in parallel with these eight first electronically controlled double-switch (511) is opened. The first electronically controlled double-switch (511) corresponding to the extended copper busbars on the four lithium batteries (1) in the Type B lithium battery pack is opened and connected in parallel with these four first electronically controlled double-switch (511) The first parallel-connected single-switch (512) will be closed and connected. During the power supply process, the lithium batteries (1) in the eight A-type lithium battery packs will continuously consume power. When the average power of the eight lithium batteries (1) in the A-type lithium battery pack is lower than 80% of the average power of the four lithium batteries in the B-type lithium battery pack, the BMS communication module will obtain the four lithium batteries (1) with the lowest power in the eight A-type lithium battery packs and disconnect the power supply of the four lithium batteries (1) with the lowest power in the A-type lithium battery packs. The replacement mode will be started to replace the power supply of the four lithium batteries (1) in the B-type lithium battery packs. S2: After the replacement mode is performed in step S1, the four lithium batteries (1) in the working A-type lithium battery pack continue to work until the average charge of these four lithium batteries is less than 60%. Then, the second replacement mode will be performed, and the four lithium batteries (1) in the A-type lithium battery pack that were replaced in the first time will continue to supply power. The subsequent replacement modes will no longer distinguish between A-type lithium battery packs and B-type lithium battery packs. The replacement will be performed based on the four lithium batteries with the lowest charge among the eight working lithium batteries. S3: If multiple replacements are performed after step S2, and the power supply voltage is low due to the low power of eight lithium batteries, nine or ten lithium batteries (1) will be connected in series to supply power so that the power supply voltage meets the requirements. At this time, the remaining two or three lithium batteries will start active equalization charging. S4: In step S3, active equalization charging is initiated by starting one of the two equalization lithium batteries (2) to supply power or by connecting the two batteries in series. When the equalization lithium battery (2) supplies power, it is powered by DC / AC. The converter (9) converts DC power into AC power, which circulates within the loop conductor (6). When the remaining two or three lithium batteries (1) are in the A-type or B-type lithium battery pack, the electronically controlled equalization start switch (612) connected in parallel to the positive winding (61) of the transformer corresponding to the A-type or B-type lithium battery pack is opened. At the same time, the electronically controlled series start switch (611) on the positive winding (61) of the transformer is closed. The electronically controlled equalization start switch (612) connected in parallel to the positive winding (61) of the transformer is closed, and its corresponding electronically controlled series start switch (611) is opened. If the positive winding (61) of the transformer is energized, it will provide interactive magnetic field lines to the corresponding secondary winding (8) of the transformer. The secondary winding (8) of the transformer will generate AC power. The AC power generated by the secondary winding (8) of the transformer is transmitted through AC / DC. When the converter (7) converts to DC power, and a certain lithium battery (1) needs to be charged evenly, the second electronic control double-switch (521) connected to it is turned off and turned on to charge the lithium battery (1) evenly. S5: In step S4, the average power of the lithium batteries that are being balanced and charged is M1. The lowest power lithium battery (1) is selected from the lithium batteries that are being supplied with power, and the average power of the lowest power lithium battery is calculated as M2. If the power of M1 is 20% higher than that of M2, a replacement mode will be activated, and the balanced charging of the lithium batteries (1) that are being balanced and charged will be cut off to replace the lowest power lithium batteries (1). The replaced lowest power lithium batteries (1) will start the balanced charging mode and charge. This step S5 is repeated to achieve balanced power supply for the entire lithium battery.

6. The lithium battery BMS active balancing method according to claim 5, characterized in that: If there are no lithium batteries with a charge of more than 95% when the two sets of type A lithium battery packs and one set of type B lithium battery packs are started to supply power (1), the two sets of type A lithium battery packs will not be started to supply power first. Instead, the power supply will be supplied according to the mode after the second replacement mode in step S2. The subsequent power supply balancing mode is the same as step S3-step S5.

7. The lithium battery BMS active balancing method according to claim 5, characterized in that: If all lithium batteries (1) have less than 40% charge, the lithium batteries that are being balanced need to be quickly charged to complete the replacement frequency of the replacement mode. At this time, two balanced lithium batteries (2) are connected in series to provide a larger voltage for balanced charging. When the balanced lithium batteries (2) are connected in series, the transformer secondary winding (8) will start the entire transformer secondary winding (8) to receive the interactive magnetic field lines emitted by the transformer positive winding (61) to obtain a larger voltage and current for balanced charging, so as to improve the charging speed.

8. The lithium battery BMS active balancing method according to claim 5, characterized in that: If a group of lithium batteries (1) is supplying power, and the discharge rate of one or more of them is significantly higher than that of other lithium batteries (1) that are supplying power, the power supply of the batteries with significantly higher power supply rates will be canceled and marked, and equalization charging will not be performed. At the same time, the spare lithium batteries will be replaced according to the number of batteries supplying power. If the number of batteries with significantly higher power supply rates is greater than or equal to four, the power supply of these batteries with significantly higher power supply rates will not be canceled, but they will still be marked.

9. The lithium battery BMS active balancing method according to claim 5, characterized in that: If the lithium battery levels in both sets of Type A lithium battery packs and one set of Type B lithium battery packs are all below 20%, the idle battery cannot be started. During the equalization charging of the battery, the lithium battery that powers the system is simultaneously and equally charged.

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