Control method, circuit and device for balanced charging based on multi-winding magnetic coupling

Abstract

The application relates to the technical field of battery balancing charging, and particularly discloses a control method, a circuit and equipment for balancing charging based on multi-winding magnetic coupling, wherein the balancing charging control circuit actively performs active balancing control on the balancing circuit and the balancing charging power conversion circuit by combining the detected power change condition of the battery pack, so that the balancing circuit and the balancing charging power conversion circuit perform balancing charging on the battery pack, the dynamic voltage and the dynamic SOC of each battery are kept relatively consistent in the use process, the available capacity of the battery is improved, the service life of the battery is prolonged, the occurrence of the wood barrel effect caused by the series mismatch of the battery is reduced, or the occurrence of the heat runaway caused by the loop current caused by the parallel charging mismatch is reduced, the overall available capacity is further improved, the service life is prolonged, and the use safety and reliability of the battery are improved.

Description

Technical Field

[0001] This invention relates to the field of battery balancing charging technology, and in particular to a control method, circuit, and device for balancing charging based on multi-winding magnetic coupling. Background Technology

[0002] Current battery systems for residential and commercial energy storage consist of multiple PACKs connected in series and parallel in different ways to achieve the required voltage and capacity. Each PACK is composed of multiple batteries connected in series. Depending on the capacity and voltage, different numbers of PACKs are connected in series to form a battery cluster. Multiple battery clusters are then used to form a container with a capacity of 100KW to several MW, ranging from small capacity of 5KWH to large capacity of tens of MWh. The number of cells is increasing, from dozens to hundreds, or even hundreds of thousands.

[0003] Currently, the common practice for cell pairing is to use initial static balancing, which utilizes the differences in ΔSOC capacity, ΔV voltage, and ΔR internal resistance between cells. However, in practice, it has been found that this method cannot achieve precise pairing. Furthermore, after N cycles of use, the lifespan, self-discharge, internal gas generation (externally characterized as a gradual increase in pressure per unit area of ​​the module), and active material SOC internal resistance of each cell become increasingly inconsistent. Moreover, the passive balancing current widely used today is only a few hundred milliamps. Compared to the charging and discharging currents of several amperes, tens of amperes, or even thousands of amperes during use, this cannot maintain relatively consistent dynamic voltage and dynamic SOC among the cells, leading to a decrease in the usable capacity and lifespan of the entire battery cabinet and battery cluster.

[0004] Therefore, it is particularly important to propose a technical solution for actively balancing the charging of the battery pack so that each cell maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby improving the usable capacity of the battery and extending its service life.

[0005] Invention Data

[0006] The technical problem to be solved by the present invention is to provide a control circuit for balanced charging based on multi-winding magnetic coupling, which can actively balance the charging of the battery pack so that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby improving the usable capacity of the battery and extending its service life.

[0007] To address the aforementioned technical problems, the first aspect of this invention discloses a control method for balanced charging based on multi-winding magnetic coupling. This method is applied to a control circuit, which includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein:

[0008] The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit; the controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit; the charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack via multi-winding magnetic coupling, and the total number of batteries is greater than or equal to 2; the controlled terminal of the equalization circuit is electrically connected to the second control terminal of the balanced charging control circuit; the direct charging terminal of the equalization circuit is used to electrically connect to the battery pack; and the detection terminal of the balanced charging control circuit is used to electrically connect to the battery pack, wherein:

[0009] The method includes:

[0010] The balance charging control circuit detects the changes in the battery charge in the battery pack, and controls the balancing circuit and the balance charging power conversion circuit to perform balance charging control operations on the battery pack according to the changes in the battery charge.

[0011] As an optional implementation, in the first aspect of the present invention, the equalization circuit includes an active charging state equalization module and a direct charging module, wherein:

[0012] The switching terminal of the active charging state balancing module is electrically connected to the power supply terminal of the direct charging module, the controlled terminal of the direct charging module is electrically connected to the first sub-control terminal of the balance charging control circuit, and the direct charging terminal of the direct charging module is used to electrically connect to the battery pack.

[0013] The balancing terminal of the active charging state balancing module is electrically connected to the balancing terminal of the balanced charging power conversion circuit, and the controlled terminal of the active charging state balancing module is electrically connected to the second sub-control terminal of the balanced charging control circuit.

[0014] The first sub-control terminal and the second sub-control terminal of the balance charging control circuit constitute the second control terminal of the balance charging control circuit. The balancing terminal of the active balancing module of the charging state is the balancing terminal of the balancing circuit, and the direct charging terminal of the direct charging module is the direct charging terminal of the balancing circuit.

[0015] As an optional implementation, in the first aspect of the present invention, the balance charging control circuit detects the changes in the charge level of the batteries in the battery pack, and controls the balancing circuit and the balance charging power conversion circuit to perform a balance charging control operation on the battery pack according to the corresponding changes in the charge level of the battery pack, including:

[0016] When the current state of the battery pack indicates that the charge of the battery in the battery pack meets the predetermined first charge condition, the balance charging control circuit generates a connection signal corresponding to the balance charging power conversion circuit, and performs a connection operation on the branch where the balance charging power conversion circuit is located according to the connection signal corresponding to the balance charging power conversion circuit, so that the balance charging power conversion circuit performs a balance charging operation on the battery pack with a preset current.

[0017] The balance charging control circuit generates a direct charging shutdown signal for the direct charging module, and stops performing direct charging operation on the battery pack according to the direct charging shutdown signal of the direct charging module. After detecting that the direct charging operation on the battery pack has stopped, it generates a current increase signal for the balance charging power conversion circuit, and performs an increase operation on the charging current of the balance charging power conversion circuit according to the current increase signal of the balance charging power conversion circuit.

[0018] During the process of performing a balancing charge operation on the battery pack with the increased charging current of the balancing charge power conversion circuit, the balancing charge control circuit monitors the changes in the battery pack's charge level to obtain a first change in the battery pack's charge level. Based on the first change in the battery pack's charge level, it generates a first current reduction signal that matches the first change in the battery pack's charge level. Based on the first current reduction signal, it reduces the charging current of the balancing charge power conversion circuit until the voltage of each battery in the battery pack is greater than or equal to a preset voltage.

[0019] As an optional implementation, in the first aspect of the present invention, the balancing charging control circuit detects the changes in the charge level of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack according to the corresponding changes in the charge level of the battery pack, further comprising:

[0020] When the current state of the battery pack indicates that the battery pack's charge level meets a predetermined second charge condition, the balance charging control circuit monitors the second charge level change of the battery pack and determines whether the current condition of the battery pack meets the determined charging current reduction condition based on the second charge level change. The charge stored in the battery pack corresponding to the second charge condition is less than the charge stored in the battery pack corresponding to the first charge condition.

[0021] When it is determined that the charging current reduction condition is met, the balance charging control circuit generates a second current reduction signal for the balance charging power conversion circuit, and performs a reduction operation on the charging current of the balance charging power conversion circuit according to the second current reduction signal.

[0022] The balance charging control circuit generates a direct charging connection signal for the direct charging module, and connects the direct charging terminal of the direct charging module to the battery pack according to the direct charging connection signal to perform a direct charging operation on the battery pack.

[0023] The balance charging control circuit generates a shutdown signal corresponding to the balance charging power conversion circuit, and shuts off the balance charging operation of the battery pack according to the shutdown signal corresponding to the balance charging power conversion circuit, and triggers the operation of generating a turn-on signal corresponding to the balance charging power conversion circuit when the current state of the battery pack is used to indicate that the charge of the battery in the battery pack meets a predetermined first charge condition.

[0024] As an optional implementation, in the first aspect of the present invention, the balancing charging control circuit detects the changes in the charge level of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack according to the corresponding changes in the charge level of the battery pack, further comprising:

[0025] When the current state of the battery pack is used to indicate that the charge of the battery in the battery pack meets a predetermined third charge condition, the balance charging control circuit generates an on signal for the equalization circuit and a first charging signal for the balance charging power conversion circuit, wherein the charge stored in the battery pack corresponding to the third charge condition is less than the charge stored in the battery pack corresponding to the second charge condition.

[0026] The balance charging control circuit controls the balance circuit to turn on the balance charging power conversion circuit according to the turn-on signal of the balance circuit, and controls the balance charging power conversion circuit to perform a charging operation on the battery pack with a first charging current that matches the first charging signal according to the first charging signal of the balance charging power conversion circuit.

[0027] The balance charging control circuit detects the third change in the battery pack's charge level, generates a second charging signal for the balance charging power conversion circuit based on the third change in the battery pack's charge level, increases the charging current of the balance charging power conversion circuit based on the second charging signal, and triggers the operation of monitoring the second change in the battery pack's charge level when the current state of the battery pack indicates that the charge level of the batteries in the battery pack meets a predetermined second charge level condition.

[0028] As an optional implementation, in the first aspect of the present invention, the method further includes:

[0029] The balance charging control circuit determines whether the direct charging terminal of the direct charging module is disconnected from the battery pack. When the determination result is yes, it triggers the operation of detecting the third change in the battery pack's charge level.

[0030] When the result is determined to be negative, the balance charging control circuit generates a first shutdown signal, and according to the first shutdown signal, disconnects the connection between the direct charging terminal of the direct charging module and the battery pack, and triggers the operation of detecting the third change in the battery pack's charge level.

[0031] As an optional implementation, in the first aspect of the present invention, the method further includes:

[0032] During the charging process of the battery pack based on the balance charging power conversion circuit, the balance charging control circuit detects the first voltage change of each battery in the battery pack and determines the voltage change type of the battery pack based on the first voltage change of each battery.

[0033] When the voltage change type corresponding to the battery pack indicates that there is a first target battery in the battery pack whose voltage change meets a predetermined first current adjustment condition, the balance charging control circuit generates a first current control signal that matches the voltage change of the first target battery, and performs a reduction operation on the current charging current of the battery pack according to the first current control signal corresponding to the first target battery; after charging the first target battery with the reduced current charging current of the first target battery, when it is determined that the current voltage change of the first target battery meets a predetermined second current adjustment condition, a second current control signal that matches the voltage change of the first target battery is generated, and performs an increase operation on the current charging current of the battery pack according to the second current control signal corresponding to the first target battery;

[0034] When the voltage change type corresponding to the battery pack is used to indicate that the voltage change of all batteries in the battery pack meets the predetermined second current regulation condition, the balance charging control circuit generates a duty cycle control signal that matches the voltage change of the battery pack, and performs a pulse width duty cycle reduction operation on the primary side corresponding to the balance charging power conversion circuit according to the duty cycle control signal, so as to reduce the current charging current of the battery pack.

[0035] As an optional implementation, in the first aspect of the present invention, when the battery pack is in a discharging state, the balancing circuit includes a discharge state active balancing module, wherein the balancing terminal of the discharge state active balancing module is electrically connected to the balancing terminal of the balancing charging power conversion circuit, and the charging terminal of the discharge state active balancing module is used to electrically connect to the battery pack; wherein the balancing terminal of the discharge state active balancing module is the balancing terminal of the balancing circuit, and the charging terminal of the discharge state active balancing module is the direct charging terminal of the balancing circuit;

[0036] The balancing charging control circuit detects changes in the battery charge levels of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on these changes, including:

[0037] When it is determined that there is a second target battery in the battery pack during the discharge process, whose current voltage is less than or equal to a predetermined voltage threshold or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold, the balance charging control circuit generates a discharge equalization signal corresponding to the second target battery and a shutdown signal corresponding to each remaining battery in the battery pack other than the second target battery. According to the discharge equalization signal, the discharge state active equalization module is turned on to connect the discharge state active equalization module to the balance charging power conversion circuit. At the same time, according to the shutdown signal corresponding to each remaining battery, the charging branch of that remaining battery is disconnected.

[0038] During the balancing charge process for the second target battery, when the difference between the voltage of the second target battery and the average voltage of all the remaining batteries is less than or equal to a preset voltage difference, the balancing charge control circuit generates a shutdown signal corresponding to the second target battery. Based on the shutdown signal, the charging branch of the second target battery is disconnected, and the operation of determining whether there is a second target battery in the battery pack during the discharge process whose current voltage is less than or equal to a predetermined voltage threshold or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold is re-executed.

[0039] The second aspect of this invention discloses a control circuit for balanced charging based on multi-winding magnetic coupling. The control circuit includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein:

[0040] The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit, the controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit, and the charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack through multi-winding magnetic coupling, and the number of all the batteries is greater than or equal to 2.

[0041] The controlled terminal of the equalization circuit is electrically connected to the second control terminal of the equalization charging control circuit, the direct charging terminal of the equalization circuit is electrically connected to the battery pack, and the detection terminal of the equalization charging control circuit is electrically connected to the battery pack.

[0042] The balance charging control circuit is used to detect the changes in the battery charge in the battery pack, and control the balancing circuit and the balance charging power conversion circuit to perform balance charging control operation on the battery pack according to the changes in the battery charge.

[0043] The third aspect of the present invention discloses a balance charging control device, the balance charging control device including a device body and a control circuit as described in any of the control methods for balance charging based on multi-winding magnetic coupling in the first aspect, wherein the device body is used to house the control circuit, and the balance charging control device is used to execute the control method for balance charging based on multi-winding magnetic coupling as described in any of the first aspects.

[0044] Implementing this invention has the following beneficial effects:

[0045] This invention provides a control method for balanced charging based on multi-winding magnetic coupling. This method is applied in a control circuit, which includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit. The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit. The controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit. The charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack via multi-winding magnetic coupling, with the total number of batteries being greater than or equal to two. The controlled terminal of the equalization circuit is electrically connected to the second control terminal of the balanced charging control circuit. The direct charging terminal of the equalization circuit is used to connect to the battery pack. The detection terminal of the balanced charging control circuit is used to connect to the battery pack. The method includes: the balanced charging control circuit detecting changes in the battery charge level in the battery pack, and controlling the equalization circuit and the balanced charging power conversion circuit to perform balanced charging control operations on the battery pack based on the corresponding changes in battery charge level. As can be seen, the balance charging control circuit of the present invention actively balances and controls the balancing circuit and the balance charging power conversion circuit by combining the detected changes in the battery pack's charge level. This enables the balancing circuit and the balance charging power conversion circuit to perform balance charging on the battery pack, ensuring that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use. This improves the battery's usable capacity and extends its lifespan, while reducing the occurrence of the "weakest link" effect caused by series mismatch and the occurrence of thermal runaway caused by parallel mismatch due to circulating current. This further improves the overall usable capacity and extends the battery's lifespan, enhancing the battery's safety and reliability. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of a control circuit for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention;

[0048] Figure 2 This is a flowchart illustrating a control method for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention.

[0049] Figure 3 This is a schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention;

[0050] Figure 4This is a schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention;

[0051] Figure 5 A schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in this embodiment of the invention;

[0052] Figure 6 This is a schematic diagram of the structure of a balance charging control device disclosed in an embodiment of the present invention. Detailed Implementation

[0053] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0054] It should be noted that, unless otherwise explicitly specified and limited, the term "electrical connection" in the specification, claims, and accompanying drawings of this invention should be interpreted broadly. For example, it can refer to a fixed electrical connection, a detachable electrical connection, or an integral electrical connection; it can be a mechanical electrical connection, an electrical-electrical connection, or a connection capable of communication; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two elements or the interaction between two elements. Furthermore, the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] Example 1

[0056] Please see Figure 1-2 , Figure 1 This is a schematic diagram of a control circuit for balanced charging based on multi-winding magnetic coupling, as disclosed in an embodiment of the present invention. Figure 2 This is a flowchart illustrating a control method for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention. Figure 2 The method is applied in Figure 1 In the control circuit, this method and circuit are applicable to one of the following types of batteries: sodium-ion battery, ternary lithium battery, and lithium iron phosphate battery. For example... Figure 1 As shown, the control circuit includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein:

[0057] The equalization terminal of the equalization power conversion circuit is electrically connected to the equalization terminal of the equalization circuit, the controlled terminal of the equalization power conversion circuit is electrically connected to the first control terminal of the equalization charging control circuit, the charging terminal of the equalization power conversion circuit is used to connect each battery in the battery pack through multi-winding magnetic coupling, and the number of batteries in the battery pack is greater than or equal to 2; the controlled terminal of the equalization circuit is electrically connected to the second control terminal of the equalization charging control circuit, the direct charging terminal of the equalization circuit is used to electrically connect to the battery pack, and the detection terminal of the equalization charging control circuit is used to electrically connect to the battery pack.

[0058] like Figure 2 As shown, the control method for balanced charging based on multi-winding magnetic coupling may include the following steps:

[0059] 101. The balance charging control circuit detects changes in the battery charge level of the batteries in the battery pack.

[0060] 102. The balance charging control circuit controls the equalization circuit and the balance charging power conversion circuit to perform balance charging control operations on the battery pack according to the changes in the corresponding battery capacity.

[0061] It is evident that implementation Figure 2 The described method involves a balance charging control circuit that actively controls the balancing circuit and the balance charging power conversion circuit by combining the detected changes in the battery pack's charge level. This allows the balancing circuit and the balance charging power conversion circuit to perform balanced charging on the battery pack, ensuring that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use. This improves the battery's usable capacity and extends its lifespan, while also reducing the occurrence of the "weakest link" effect caused by series mismatch or the occurrence of thermal runaway caused by circulating current due to parallel charging mismatch. Ultimately, this enhances the overall usable capacity, extends the battery's lifespan, and improves the battery's safety and reliability.

[0062] In this embodiment of the invention, optionally, such as Figure 3 As shown, Figure 3 This is a schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention, as shown below. Figure 3 As shown, the equalization circuit includes an active charging state equalization module and a direct charging module, wherein:

[0063] The switching terminal of the active balancing module is electrically connected to the power supply terminal of the direct charging module. The controlled terminal of the direct charging module is electrically connected to the first sub-control terminal of the balancing charging control circuit. The direct charging terminal of the direct charging module is used to electrically connect to the battery pack, such as... Figure 3 The diagram illustrates a battery pack consisting of two batteries, specifically the batteries at the terminals of the battery pack that are electrically connected.

[0064] The balancing terminal of the active balancing module is electrically connected to the balancing terminal of the balance charging power conversion circuit, and the controlled terminal of the active balancing module is electrically connected to the second sub-control terminal of the balance charging control circuit.

[0065] Among them, the first sub-control terminal and the second sub-control terminal of the balance charging control circuit constitute the second control terminal of the balance charging control circuit, the equalization terminal of the active equalization module of the charging state is the equalization terminal of the equalization circuit, and the direct charging terminal of the direct charging module is the direct charging terminal of the equalization circuit.

[0066] In this embodiment of the invention, the direct charging module may include a direct charging switch and a direct charging power conversion module. The direct charging switch may be integrated into the direct charging power conversion module or may be independent of it. When independent of the direct charging power conversion module, the controlled terminal of the direct charging power conversion module and the controlled terminal of the direct charging switch are electrically connected to a sub-control terminal and another sub-control terminal of the balance charging control circuit, respectively. The sub-control terminal and the other sub-control terminal of the balance charging control circuit constitute the first sub-control terminal of the balance charging control circuit. The power supply terminal of the direct charging power conversion module is simultaneously electrically connected to the switch terminal of the active balancing charging module and the switch terminal of the direct charging switch. The direct charging terminal of the direct charging switch is used to electrically connect to the battery pack, specifically, to the battery located at the end point of the battery pack. The direct charging power conversion module provides the power source VIN for both balance charging and direct charging of the battery.

[0067] In this embodiment of the invention, optionally, such as Figure 4 As shown, Figure 4 This is a schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in an embodiment of the present invention, as shown below. Figure 4 As shown, the balancing circuit includes an active balancing module for discharge state, wherein the balancing terminal of the active balancing module for discharge state is electrically connected to the balancing terminal of the balancing power conversion circuit, and the charging terminal of the active balancing module for discharge state is used to electrically connect to the battery pack; wherein, the balancing terminal of the active balancing module for discharge state is the balancing terminal of the balancing circuit, and the charging terminal of the active balancing module for discharge state is the direct charging terminal of the balancing circuit.

[0068] In further optional embodiments of the present invention, such as Figure 3 and Figure 4As shown, the control circuit also includes a rectifier control switch circuit and a multi-winding magnetic coupling transformer. The multi-winding magnetic coupling transformer consists of a primary winding and multiple secondary windings. Furthermore, an iron core is provided between the primary winding and all secondary windings. The rectifier control switch circuit consists of multiple rectifier control switch modules, and the number of all rectifier control switch modules equals the number of secondary windings, which equals the number of batteries in the battery. Each rectifier control switch module has a unique corresponding battery and secondary winding. For any rectifier control switch module, the charging terminal of the balance charging power conversion circuit is coupled to the corresponding secondary winding of the rectifier control switch module through the primary winding of the multi-winding magnetic coupling transformer. The controlled terminal of the rectifier control switch module is electrically connected to the third control terminal of the balance charging control circuit, and the control terminal of the rectifier control switch module is used to electrically connect to the battery corresponding to that rectifier control switch module.

[0069] In this embodiment of the invention, optionally, when the battery pack is in a discharging state, the balancing charging control circuit detects the changes in the charge level of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack according to the corresponding changes in the charge level of the battery pack, including:

[0070] When the current state of the battery pack indicates that the battery charge in the battery pack meets the predetermined first charge condition, the balance charging control circuit generates the corresponding turn-on signal for the balance charging power conversion circuit, and performs a turn-on operation on the branch where the balance charging power conversion circuit is located according to the turn-on signal for the balance charging power conversion circuit, so that the balance charging power conversion circuit performs a balance charging operation on the battery pack with a preset current.

[0071] The balance charging control circuit generates a direct charging shutdown signal for the direct charging module and stops performing direct charging operation on the battery pack according to the direct charging shutdown signal. After detecting that the direct charging operation on the battery pack has stopped, it generates a current increase signal for the balance charging power conversion circuit and increases the charging current of the balance charging power conversion circuit according to the current increase signal.

[0072] During the process of performing a balancing charge operation on the battery pack with the increased charging current of the balancing charge power conversion circuit, the balancing charge control circuit monitors the changes in the battery pack's charge level to obtain the first change in the battery pack's charge level. Based on the first change in the battery pack's charge level, it generates a first current reduction signal that matches the first change in the battery pack's charge level. Based on the first current reduction signal, it reduces the charging current of the balancing charge power conversion circuit until the voltage of each battery in the battery pack is greater than or equal to a preset voltage.

[0073] In this embodiment of the invention, optionally, the balance charging control circuit detects the changes in the charge level of the batteries in the battery pack (such as changes in charge). When the changes in charge level indicate that the current charge of the battery pack is within a predetermined first range (such as 85%-90% of the full charge of the battery pack) and / or the voltage of each battery in the battery pack is stable within a predetermined first voltage range (such as 3.3V-3.5V, taking lithium iron phosphate batteries as an example), it indicates that the charge level of the batteries in the battery pack meets the predetermined first charge level condition. At this time, it can be understood as any charge level in the full charge segment.

[0074] In this embodiment of the invention, the active balancing module connects to the balancing power conversion circuit, indicating that the branch where the balancing power conversion circuit is located is connected. At this time, the battery pack can be charged with a small current (such as 5%-10% of the rated current), and the electrical connection between the direct charging module (more specifically, the direct charging switch) and the battery pack is turned off to stop direct charging. Then, the charging current of the balancing power conversion circuit is increased, such as reaching 30% of the rated current. The battery pack's charge level is monitored. For each battery, the charging current of the balancing power conversion circuit is reduced once for every preset voltage increase (such as 5mV) or every preset voltage increase slope increase (such as 0.1) until all batteries are charged to the preset voltage, such as the voltage corresponding to 98% full charge.

[0075] As can be seen, if the optional embodiment detects that the battery pack has a large amount of charge, it first selects a smaller balance charging current, then turns off the direct charging, then increases the balance charging current, and then gradually decreases the current according to the change in battery charge. This ensures that the charged charge does not cause the voltage to rise sharply, but rather maintains a stable and consistent rise in the voltage of each battery cell, further improving the consistency of battery dynamic voltage and dynamic SOC.

[0076] In a further optional embodiment of the present invention, the balancing charging control circuit detects the changes in the battery charge level of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on the corresponding changes in the battery charge level. The method further includes:

[0077] When the current state of the battery pack indicates that the charge of the batteries in the battery pack meets the predetermined second charge condition, the balance charging control circuit monitors the second charge change of the battery pack and determines whether the current condition of the battery pack meets the determined charging current reduction condition based on the second charge change of the battery pack. The charge stored in the battery pack corresponding to the second charge condition is less than the charge stored in the battery pack corresponding to the first charge condition.

[0078] When it is determined that the charging current reduction condition is met, the balance charging control circuit generates a second current reduction signal for the balance charging power conversion circuit, and performs a reduction operation on the charging current of the balance charging power conversion circuit according to the second current reduction signal.

[0079] The balance charging control circuit generates a direct charging connection signal for the direct charging module, and connects the direct charging terminal of the direct charging module to the battery pack according to the direct charging connection signal to perform a direct charging operation on the battery pack.

[0080] The balance charging control circuit generates a shutdown signal corresponding to the balance charging power conversion circuit, and shuts off the balance charging operation of the battery pack according to the shutdown signal corresponding to the balance charging power conversion circuit. It also triggers the operation of generating a turn-on signal corresponding to the balance charging power conversion circuit when the current state of the battery pack indicates that the battery charge in the battery pack meets the predetermined first charge condition.

[0081] In this embodiment of the invention, optionally, the balance charging control circuit detects the changes in the charge level of the batteries in the battery pack (such as charge changes). When the changes in charge level indicate that the current charge of the battery pack is within a predetermined second charge range (such as 15%-18% of the full charge of the battery pack) and / or the voltage of each battery in the battery pack is stable within a predetermined second voltage range (such as 3.18V-3.20V, taking lithium iron phosphate batteries as an example), it indicates that the charge level of the batteries in the battery pack meets the predetermined second charge level condition. At this time, it can be understood as any charge level within the capacity range.

[0082] In this embodiment of the invention, optionally, when the second charge change of the battery pack is used to indicate that the current charge of the battery pack is within a predetermined third charge range (e.g., 18%-23% of the full charge of the battery pack) and / or the voltage of each battery in the battery pack is stable within a predetermined third voltage range (e.g., 3.20V-3.21V, taking lithium iron phosphate batteries as an example), it indicates that the charging current reduction condition is met. According to the generated second current reduction signal, the charging current of the balancing charging power conversion circuit is reduced, such as to 5%-10% of the rated current. Then, the direct charging switch is turned on to perform direct charging operation on the battery pack, and the balancing charging power conversion circuit is turned off. The balancing charging power conversion circuit can be turned off by turning off the active balancing module or turning off the balancing charging power conversion module, that is, stopping the charging of the battery pack through the balancing charging power conversion circuit. It should be noted that since this starts from a certain charge level, when the battery pack is directly charged, the operation of generating the connection signal corresponding to the balance charging power conversion circuit when the current state of the battery pack indicates that the charge level of the batteries in the battery pack meets the predetermined first charge level condition can continue to be performed. This can be understood as changing from the capacity segment to the full charge segment, that is, continuing to perform the charging operation corresponding to the full charge segment.

[0083] As can be seen, in the embodiments of the present invention, if the battery pack has a certain amount of charge, the equalization charging current is reduced first and then the direct charging switch is turned on to the battery pack. That is, when the voltage of each battery in the battery pack is basically equal, the battery pack is directly charged, and then the charging of the battery pack through the equalization charging power conversion module is turned off. This improves the consistency of the battery dynamic voltage and dynamic SOC, while reducing the power consumption of the equalization charging power conversion circuit and the active equalization charging state module.

[0084] In a further embodiment of the present invention, the balance charging control circuit detects the changes in the battery charge level of the batteries in the battery pack, and controls the balancing circuit and the balance charging power conversion circuit to perform balance charging control operations on the battery pack based on the corresponding changes in the battery charge level. The method also includes:

[0085] When the current state of the battery pack is used to indicate that the charge of the battery in the battery pack meets the predetermined third charge condition, the balance charging control circuit generates the connection signal of the equalization circuit and the first charging signal of the balance charging power conversion circuit. The charge stored in the battery pack corresponding to the third charge condition is less than the charge stored in the battery pack corresponding to the second charge condition.

[0086] The balance charging control circuit controls the balance circuit to turn on the balance charging power conversion circuit according to the turn-on signal of the balance circuit, and controls the balance charging power conversion circuit to perform a charging operation on the battery pack with a first charging current that matches the first charging signal according to the first charging signal of the balance charging power conversion circuit.

[0087] The balance charging control circuit detects the third change in the battery pack's charge level and generates a second charging signal for the balance charging power conversion circuit based on this change. It then increases the charging current of the balance charging power conversion circuit based on the second charging signal and triggers the aforementioned operation of monitoring the second change in the battery pack's charge level when the current state of the battery pack indicates that the charge level of the batteries in the battery pack meets a predetermined second charge level condition.

[0088] In this embodiment of the invention, optionally, the balance charging control circuit detects the changes in the battery capacity (e.g., charge change) of the batteries in the battery pack. When the changes in battery capacity indicate that the current charge of the battery pack is within a predetermined fourth charge range (e.g., less than 0.5% of the battery pack's full charge) and / or the voltage of each battery in the battery pack is stable within a predetermined fourth voltage range (e.g., 2.8V-2.9V, taking lithium iron phosphate batteries as an example), it indicates that the battery capacity in the battery pack meets a predetermined third capacity condition. This can be understood as any capacity condition in the depleted state. The balance charging power conversion circuit and the active charging state balancing module are then connected to perform a charging operation on the battery pack with a first charging current (e.g., 5%-10% of the rated current).

[0089] In this embodiment of the invention, optionally, when the third charge change status of the battery pack is used to indicate that the current charge of the battery pack changes from one charge state to another (e.g., from 1% to 5% to 20% of the full charge), the charging current of the balance charging power conversion circuit is increased sequentially until the rated current is reached to charge the battery pack. It should be noted that since this starts from a very low charge state, when charging the battery pack with the rated current, the operation described above, which monitors the second charge change status of the battery pack when the current state of the battery pack indicates that the charge of the batteries in the battery pack meets the predetermined second charge condition, can continue to be performed. This can be understood as changing from a depleted state to a capacity state, i.e., continuing to perform the charging operation corresponding to the capacity state.

[0090] In this embodiment of the invention, it should be noted that when the current state of the battery pack is used to indicate that the battery charge in the battery pack meets the predetermined third charge condition, or when the balance charging power conversion circuit and the active charging state balancing module are turned on, if the active discharging state balancing module is turned on, the active discharging state balancing module needs to be turned off to prevent the battery pack from discharging further and becoming further depleted, while improving the accuracy and reliability of equalizing the battery pack through the active charging state balancing module and the balance charging power conversion circuit.

[0091] As can be seen, in the embodiments of the present invention, if the battery pack's charge level is detected to be very low, the battery pack is first charged with a small current through the active balancing module and the balancing charging power conversion circuit. Then, according to the changes in the battery pack's charge level, the charging current is increased sequentially to charge the battery pack in sequence, thereby further improving the accuracy and reliability of balancing charging of the battery pack when the charge level is low.

[0092] In an optional embodiment, the method may further include the following steps:

[0093] The balance charging control circuit determines whether the direct charging terminal of the direct charging module is disconnected from the battery pack. When the result is yes, it triggers the execution of the above-mentioned operation of detecting the third change in battery charge.

[0094] When the result is determined to be negative, the balance charging control circuit generates a first shutdown signal, and according to the first shutdown signal, disconnects the connection between the direct charging terminal of the direct charging module and the battery pack, and triggers the execution of the above-mentioned operation of detecting the third change in battery charge.

[0095] In this optional embodiment, during the process of the balancing charging power conversion circuit performing a charging operation on the battery pack with a first charging current that matches the first charging signal, if the direct charging terminal of the direct charging switch has been disconnected from the battery pack, the battery pack will continue to be charged through the active balancing module of charging state; if the connection has not been disconnected, the connection will be disconnected first, and then the battery pack will be charged through the active balancing module of charging state.

[0096] As can be seen, in this optional embodiment, when the battery pack is in a low charge state, if the direct charging branch of the battery pack is connected at this time, it will be disconnected first, and then the battery pack will be actively balanced and charged through the active balancing module and the balance charging power conversion circuit, which further improves the charging efficiency of the battery pack while actively balancing and charging the battery pack.

[0097] In another alternative embodiment, the method may further include the following steps:

[0098] During the charging process of the battery pack based on the balance charging power conversion circuit, the balance charging control circuit detects the first voltage change of each battery in the battery pack and determines the voltage change type of the battery pack based on the first voltage change of each battery.

[0099] When the voltage change type corresponding to the battery pack indicates that there is a first target battery in the battery pack whose voltage change meets the predetermined first current adjustment condition, the balance charging control circuit generates a first current control signal that matches the voltage change of the first target battery, and performs a reduction operation on the current charging current of the battery pack according to the first current control signal corresponding to the first target battery; after charging the first target battery with the reduced current charging current of the first target battery, when it is determined that the current voltage change of the first target battery meets the predetermined second current adjustment condition, a second current control signal that matches the current voltage change of the first target battery is generated, and performs an increase operation on the current charging current of the battery pack according to the second current control signal corresponding to the first target battery.

[0100] When the voltage change type corresponding to the battery pack is used to indicate that the voltage change of all batteries in the battery pack meets the predetermined second current regulation condition, the balance charging control circuit generates a duty cycle control signal that matches the voltage change of the battery pack. Based on the duty cycle control signal, the circuit performs a pulse width duty cycle reduction operation on the primary side corresponding to the balance charging power conversion circuit to reduce the current charging current of the battery pack.

[0101] In this optional embodiment, the balance charging control circuit performs a reduction operation on the current charging current of the battery pack according to the first current control signal corresponding to the first target battery, including:

[0102] The balance charging control circuit controls the rectifier control switch module corresponding to the first target battery to turn off according to the first current control signal corresponding to the first target battery, or performs a pulse width duty cycle reduction operation on the rectifier control switch module corresponding to the first target battery to reduce the current charging current of the first target battery.

[0103] Furthermore, the balance charging control circuit, based on the second current control signal corresponding to the first target battery, performs an increase operation on the current charging current of the battery pack, including:

[0104] The balance charging control circuit controls the rectifier control switch module corresponding to the first target battery to turn on according to the second current control signal corresponding to the first target battery, / or performs a pulse width duty cycle increase operation on the rectifier control switch module corresponding to the first target battery to increase the current charging current of the first target battery.

[0105] It should be noted that this optional embodiment can occur during the balancing charge process corresponding to the aforementioned first charge condition, second charge condition, third charge condition, or the boundary between two of these conditions. The number of the second target batteries may be one, two, or even other numbers, and the specific second target batteries and their corresponding numbers may be the same or different at different times, which is a dynamic process.

[0106] In this optional embodiment, the first current regulation condition includes that its voltage is higher than the difference between the voltage and the average voltage of all other batteries in the battery pack at the current moment is less than or equal to a preset voltage difference, such as 10mV, or that its voltage rise slope is greater than or equal to a preset rise slope, such as 2%. The second current regulation condition includes that the voltage rise slope of all batteries in the battery pack is greater than or equal to a preset rise slope.

[0107] In this optional embodiment, if the balance charging control circuit consists of a control chip MCU and a feedback loop, then whether the duty cycle of the rectifier control switch module is changed or the duty cycle of the primary side of the balance charging power conversion circuit is changed, the change is controlled by the feedback loop according to the corresponding current control signal.

[0108] In this optional embodiment, regarding the switching between the direct charging power conversion module and the balancing charging power conversion circuit, when a second target battery is detected, the battery pack is first charged through the balancing charging power conversion circuit using a small preset current (e.g., 5%-10% of the rated current). Then, the output current of the direct charging power conversion module is gradually reduced, the direct charging switch is turned off, and the battery pack is charged through the balancing charging power conversion circuit. The corresponding duty cycle is then changed, or the rectifier control switch module is turned off. When the voltage of all batteries in the battery pack is the same, charging is performed using a small preset current (e.g., 5%-10% of the rated current), and the direct charging switch is turned on to increase the direct charging current to the rated value for direct charging. This cycle repeats continuously, dynamically maintaining consistent voltage across all cells throughout the charging process.

[0109] As can be seen, this optional embodiment analyzes the voltage changes of the batteries in the battery pack regardless of the charging stage. If the voltage of a certain battery is too high or rises too quickly, charging is stopped or the duty cycle of the corresponding secondary-side rectifier control switch module is reduced, thereby reducing the average charging current of that circuit and making the voltage rise rate of that battery more gradual and consistent with the other batteries. Conversely, charging is started or the duty cycle is increased, thereby increasing the average charging current of that circuit, making it consistent with the other batteries while improving the charging efficiency of that battery. If the voltage of all batteries rises too quickly, the duty cycle of the primary side is reduced to reduce the average charging current of all batteries, making the voltage rise rate more gradual and preventing the battery voltage from being artificially high. That is, by dynamically adjusting the voltage and charging current of each battery according to the different voltage conditions of the batteries in the battery pack, the voltage and capacity of each battery are made as consistent as possible, and the batteries are not overcharged, nor are they triggered by primary or secondary overvoltage or overcharge protection.

[0110] In this embodiment of the invention, when the battery pack is in a discharging state, the balancing charging control circuit detects the changes in the charge level of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack according to the corresponding changes in the charge level of the battery pack, including:

[0111] When it is determined that there is a second target battery in the battery pack during the discharge process whose current voltage is less than or equal to a predetermined voltage threshold (e.g., 20mV) or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold, the balance charging control circuit generates a discharge equalization signal corresponding to the second target battery and a shutdown signal corresponding to each remaining battery in the battery pack other than the second target battery. According to the discharge equalization signal, the discharge state active equalization module is turned on to connect the discharge state active equalization module to the balance charging power conversion circuit. At the same time, according to the shutdown signal corresponding to each remaining battery, the charging branch of that remaining battery is disconnected.

[0112] During the balancing charge process for the second target battery, when the difference between the voltage of the second target battery and the average voltage of all remaining batteries is less than or equal to a preset voltage difference (e.g., 1mV), the balancing charge control circuit generates a shutdown signal corresponding to the second target battery. Based on the shutdown signal, the charging branch of the second target battery is disconnected, and the system re-determines whether there is a second target battery in the battery pack during the discharge process whose current voltage is less than or equal to a predetermined voltage threshold or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold. The same process is then continued.

[0113] In this optional embodiment, during discharge, batteries with high internal resistance experience a larger rate of external voltage drop. The external voltage can be equivalent to the battery voltage minus the internal resistance voltage. Optionally, if the direct charging switch is detected to be electrically connected to the battery pack, or if the direct charging power conversion module, the active balancing module for charging state transition, and the branch containing the balance charging control circuit are detected to be connected, then the circuit must be turned off first. It should be noted that the active balancing module for charging state transition also functions as the switch for the balance charging control circuit.

[0114] In this optional embodiment, specifically, according to the discharge equalization signal, the active equalization module for discharge state is turned on to connect with the balance charging power conversion circuit. Simultaneously, according to the shutdown signal corresponding to each remaining battery, the charging branch of that remaining battery is disconnected, i.e., the rectifier control switch module corresponding to that remaining battery is turned off, or the duty cycle of the corresponding rectifier switch control module is set to 0, so that the second target battery is charged through the rectifier control switch module corresponding to the second target battery during the battery pack discharge process. According to the shutdown signal corresponding to the second target battery, the charging branch of the second target battery is disconnected. Specifically, according to the shutdown signal corresponding to the second target battery, the rectifier control switch module corresponding to the second target battery is turned off, or the active equalization module for discharge state is turned off, or the balance charging power conversion circuit is turned off, or the duty cycle of the corresponding rectifier switch control module is set to 0, to stop charging the second target battery.

[0115] It should be noted that the battery discharge process and the charging process are interchangeable.

[0116] As can be seen, this optional embodiment monitors the voltage between batteries during the discharge process of the battery pack, and when inconsistencies are detected, adjusts and controls the charging current and voltage in real time according to the inconsistency situation. This process is repeated to dynamically maintain the voltage consistency of each cell throughout the discharge process.

[0117] It should be noted that, regardless of whether it is dynamic active balancing charging or discharging, the more batteries that need to be charged simultaneously, the larger the duty cycle of the primary side of the balancing charging power conversion circuit will be, and the smaller the number of batteries that need to be charged simultaneously, the smaller the duty cycle of the primary side of the balancing charging power conversion circuit will be. In addition, the charging voltage and charging current will be adjusted in real time according to the number of batteries being charged, the charging / discharging state, different stages of the battery pack (such as the depleted stage, the capacity stage, and the fully charged stage), the changes in the amount of charge at different times during the charging and discharging process of the battery pack, the number of cycle lifespans (such as calendar lifespan and actual group working lifespan), and the internal resistance of the batteries, in order to achieve dynamic balancing charging of the battery pack.

[0118] Example 2

[0119] The present invention discloses a control circuit for balanced charging based on multi-winding magnetic coupling, such as... Figure 1 As shown, it includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein:

[0120] The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit; the controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit; the charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack via multi-winding magnetic coupling, and the total number of batteries is greater than or equal to 2; the controlled terminal of the equalization circuit is electrically connected to the second control terminal of the balanced charging control circuit; the direct charging terminal of the equalization circuit is used to electrically connect to the battery pack; and the detection terminal of the balanced charging control circuit is used to electrically connect to the battery pack. Wherein:

[0121] The balance charging control circuit is used to detect the changes in the battery charge in the battery pack, and control the equalization circuit and the balance charging power conversion circuit to perform balance charging control operations on the battery pack according to the corresponding changes in the battery charge.

[0122] In this embodiment of the invention, Figure 5 A schematic diagram of another control circuit for balanced charging based on multi-winding magnetic coupling disclosed in this invention is shown below. Figure 5 As shown, the balance charging control circuit can be a control chip MCU, and can also include a feedback loop, such as... Figure 5As shown, the communication terminal of the control chip MCU is electrically connected to the communication terminal of the feedback loop. The first and second feedback terminals of the feedback loop are electrically connected to the controlled terminals of the balanced charging power conversion circuit, respectively. Both the grounding terminal of the feedback loop and the grounding terminal of the balanced charging power conversion circuit are used for grounding. Specifically, the feedback loop can be a circuit using optocouplers or isolation amplifiers for isolation. Furthermore, current detection can be achieved by measuring the voltage across the sampling resistor Rs. Taking four series-connected batteries BTAT1, BTAT2, BTAT3, and BTAT4 as an example, the charge stages corresponding to the first, second, and third charge conditions are defined as the full charge stage, capacity stage, and depletion stage, respectively. The battery pack includes these three stages, and this is combined with... Figure 1 , Figure 3 , Figure 4 , Figure 5 The working principle of the control circuit for balanced charging based on multi-winding magnetic coupling in the embodiments of the present invention is explained as follows:

[0123] When the battery pack is detected to be in a low-charge state during charging, the MCU first controls the direct charging power conversion module (which is the source of power VIN during charging) and the active balancing module during charging, and controls the balance charging power conversion module to open through the feedback loop, so that the branches of the three are open. The active balancing module during discharging is then turned off. At this time, the charging current of the balance charging power conversion module is set to 5%-10% of the rated charging current. Then, the electrical connection between the direct charging switch and the battery pack is turned off. The SOC change of the battery pack is detected in real time, from 1% to 15% to 20%. Based on this SOC change, the charging current is gradually increased to the rated current. During active equalization charging at rated current, if the voltage rise rate of one or more cells is detected to be too rapid (e.g., greater than 2%), or if its voltage exceeds the average voltage of all other cells in the battery pack by 10mV at the current moment, the feedback loop rapidly reduces the duty cycle of the secondary side of the corresponding rectifier control switch module or shuts down the corresponding rectifier control switch module. This reduces the charging current of that cell, causing its voltage rise rate to level off and become consistent with the other cells. Once the voltage of that cell drops to the average voltage of the other cells, then... By activating the corresponding rectifier control switch module or increasing the duty cycle on the secondary side of the corresponding rectifier control switch module, the charging current is prevented from becoming excessive, and the voltage rise is made more gradual. This dynamically adjusts the voltage and charging current of each battery cell, ensuring consistent voltage and capacity across all cells. If the voltage rise rate of all cells in the battery pack is detected to be too rapid, such as exceeding 2%, the duty cycle on the primary side of the balancing charging power conversion circuit is reduced through a feedback loop. This reduces the average charging current of all cells, smooths out the voltage rise rate, and prevents artificially high battery voltage. Continued monitoring of the battery pack... Regarding battery charge changes, when the battery pack's SOC reaches 18%-23% or each battery's voltage reaches the corresponding SOC value, first reduce the balancing charging current to 5%-10% of the rated charging current, then turn on the direct charging switch, and then turn off the balancing charging power conversion circuit to directly charge the battery pack. At this time, the voltage of each cell in the battery pack is basically the same, with a voltage difference not exceeding 5mV. When charging reaches the beginning of the full charge stage, such as 85%-90% SOC, the battery voltages are 3.36V, 3.4V, 3.41V, and 3.42V respectively. Then start the balancing charging... The system uses a balanced charging power conversion circuit and sets the charging current to 5%-10% of the rated charging current. Then, the direct charging switch is turned off, and the balanced charging current is adjusted to 30% of the rated charging current. Based on the voltage change and the rise slope, the balanced charging current is gradually reduced in 5mV increments to ensure that the charged amount of electricity does not cause a sharp rise in voltage, but rather maintains a slow and stable rise in the voltage of each cell. This dynamically maintains the voltage of each battery cell to be consistent until the voltage of each cell is equal when fully charged. This ensures that the voltage / capacity of each cell is basically the same, preventing overcharging and avoiding triggering the first and second level overvoltage / overcharge protection.Specifically, regarding the switching between the direct charging power conversion module and the balance charging power conversion circuit, during the charging process, whether in the depleted section, the capacity section, the fully charged section, or the boundary between two sections, if a high voltage (e.g., greater than the current arithmetic average of 10mV) and / or a high voltage rise rate is detected in a certain cell, exceeding the limit, the battery pack will first be charged with a small current balance charge (5%-10%) through the balance charging power conversion circuit, and then the direct charging switch will be turned off, leaving only the balance charging power conversion circuit to charge each cell.

[0124] During the discharge phase, batteries with high internal resistance experience a greater rate of voltage drop. When a battery's voltage is detected to be low (e.g., less than 20mV) or has a large rate of voltage drop, the active balancing module for the discharge phase is activated, connecting it to the balance charging power conversion module. The direct charging switch, the active balancing module (which also functions as the switch module for the balance charging power conversion circuit), and the direct charging power conversion module are then deactivated. At this time, the total battery voltage of the battery pack is used to charge the current battery through the active balancing module, the balance charging power conversion circuit, and the corresponding rectifier control switch module. The rectifier control switches for the other batteries are deactivated. When the voltage reaches the average value of all other battery cells, the balance charging is deactivated. The charging current and voltage are adjusted and controlled in real time, and this cycle repeats continuously to dynamically maintain consistent voltage across all cells throughout the discharge process.

[0125] It should be noted that for the descriptions of the balancing circuit, the balancing charging power conversion circuit, and the balancing charging control circuit, please refer to the descriptions in Embodiment 1, which will not be repeated here. It should also be noted that this can be extended to any number of batteries, such as 5 batteries connected in series, 6 batteries connected in series, or 24 batteries connected in series; this embodiment of the invention is not limited to any particular number of batteries.

[0126] It is evident that implementation Figure 5 The described control circuit for balanced charging based on multi-winding magnetic coupling includes a balanced charging control circuit, a balanced charging power conversion circuit, and an equalization circuit. Based on the balanced charging control circuit's detection of battery pack charge changes, it actively controls the equalization circuit and the balanced charging power conversion circuit to perform balanced charging of the battery pack. This ensures that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby improving the battery's usable capacity and extending its lifespan. It also reduces the occurrence of the "weakest link" effect caused by series battery mismatch or the occurrence of thermal runaway caused by circulating current due to parallel charging mismatch, further improving overall usable capacity, extending lifespan, and enhancing battery safety and reliability.

[0127] Example 3

[0128] Please see Figure 6 As shown, Figure 6 This is a schematic diagram of a balance charging control device disclosed in an embodiment of the present invention. This balance charging control device can perform balance charging when the battery pack is charging or when it is discharging. The balance charging control device includes a device body and a control circuit, wherein the control circuit is as follows: Figure 1 , Figure 3 , Figure 4 , Figure 5 The circuit described herein is used to execute the control method for balanced charging based on multi-winding magnetic coupling as described in Embodiment 1.

[0129] It should be noted that for a detailed description of the control circuit for balanced charging based on multi-winding magnetic coupling, and for a detailed description of the control method for balanced charging based on multi-winding magnetic coupling, please refer to the specific descriptions of the relevant content in Embodiments 1 and 2. This embodiment will not repeat them.

[0130] It is evident that implementation Figure 6 The described balance charging control device, through its balance charging control circuit, balance charging power conversion circuit, and equalization circuit, actively controls the equalization circuit and balance charging power conversion circuit based on the balance charging control circuit and the detected changes in the battery pack's charge level. This allows the equalization circuit and balance charging power conversion circuit to perform balance charging on the battery pack, ensuring that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use. This improves the battery's usable capacity and extends its lifespan, while reducing the occurrence of the "weakest link" effect caused by series battery mismatch or the occurrence of thermal runaway caused by circulating current due to parallel battery charging mismatch. Ultimately, this improves the overall usable capacity, extends the battery's lifespan, and enhances the battery's safety and reliability.

[0131] The foregoing has provided a detailed description of a control method, circuit, and device for balanced charging based on multi-winding magnetic coupling disclosed in the embodiments of the present invention. Specific embodiments have been used to illustrate the principles and implementation methods of the present invention. However, the above preferred embodiments are not intended to limit the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A control method for balanced charging based on multi-winding magnetic coupling, characterized in that, The method is applied in a control circuit, which includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein: The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit; the controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit; the charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack via multi-winding magnetic coupling, and the number of all the batteries is greater than or equal to 2; the controlled terminal of the equalization circuit is electrically connected to the second control terminal of the balanced charging control circuit; the direct charging terminal of the equalization circuit is used to electrically connect to the battery pack; and the detection terminal of the balanced charging control circuit is used to electrically connect to the battery pack. The method includes: The balance charging control circuit detects the changes in the battery charge in the battery pack, and controls the equalization circuit and the balance charging power conversion circuit to perform balance charging control operations on the battery pack according to the changes in the battery charge. The balancing charging control circuit detects changes in the battery charge levels of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on these changes, including: When the current state of the battery pack indicates that the charge of the batteries in the battery pack meets a predetermined first charge condition, the balance charging control circuit generates a connection signal corresponding to the balance charging power conversion circuit, and performs a connection operation on the branch where the balance charging power conversion circuit is located according to the connection signal corresponding to the balance charging power conversion circuit, so that the balance charging power conversion circuit performs a balance charging operation on the battery pack with a preset current. When the charge change indicates that the current charge of the battery pack is within a predetermined first range and / or the voltage of each battery in the battery pack is stable within a predetermined first voltage range, it indicates that the charge of the batteries in the battery pack meets the first charge condition. The balance charging control circuit generates a direct charging shutdown signal for the equalization circuit, and stops performing direct charging operation on the battery pack according to the direct charging shutdown signal of the equalization circuit. After detecting that the direct charging operation on the battery pack has stopped, the balance charging power conversion circuit generates a current increase signal, and performs an increase operation on the charging current of the balance charging power conversion circuit according to the current increase signal of the balance charging power conversion circuit. During the balancing charge operation of the battery pack using the increased charging current of the balancing charge power conversion circuit, the balancing charge control circuit monitors the changes in the battery pack's charge level to obtain a first change in the battery pack's charge level. Based on this first change in charge level, it generates a first current reduction signal that matches the first change in charge level. Then, based on this first current reduction signal, it reduces the charging current of the balancing charge power conversion circuit until the voltage of each battery in the battery pack is greater than or equal to a preset voltage. Specifically, for each battery in the battery pack whose voltage increases by the preset voltage or whose voltage increase slope increases by the preset slope, the charging current of the balancing charge power conversion circuit is reduced once, until all batteries are charged to the preset voltage.

2. The control method for balanced charging based on multi-winding magnetic coupling according to claim 1, characterized in that, The equalization circuit includes an active charging state equalization module and a direct charging module, wherein: The switching terminal of the active charging state balancing module is electrically connected to the power supply terminal of the direct charging module, the controlled terminal of the direct charging module is electrically connected to the first sub-control terminal of the balance charging control circuit, and the direct charging terminal of the direct charging module is used to electrically connect to the battery pack. The balancing terminal of the active charging state balancing module is electrically connected to the balancing terminal of the balanced charging power conversion circuit, and the controlled terminal of the active charging state balancing module is electrically connected to the second sub-control terminal of the balanced charging control circuit. The first sub-control terminal and the second sub-control terminal of the balance charging control circuit constitute the second control terminal of the balance charging control circuit. The balancing terminal of the active balancing module of the charging state is the balancing terminal of the balancing circuit, and the direct charging terminal of the direct charging module is the direct charging terminal of the balancing circuit.

3. The control method for balanced charging based on multi-winding magnetic coupling according to claim 2, characterized in that, The balancing charging control circuit detects the changes in the battery charge of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on the corresponding changes in the battery charge. The circuit also includes: When the current state of the battery pack indicates that the battery pack's charge level meets a predetermined second charge condition, the balance charging control circuit monitors the second charge level change of the battery pack and determines whether the current condition of the battery pack meets the determined charging current reduction condition based on the second charge level change. The charge stored in the battery pack corresponding to the second charge condition is less than the charge stored in the battery pack corresponding to the first charge condition. When it is determined that the charging current reduction condition is met, the balance charging control circuit generates a second current reduction signal for the balance charging power conversion circuit, and performs a reduction operation on the charging current of the balance charging power conversion circuit according to the second current reduction signal. The balance charging control circuit generates a direct charging connection signal for the direct charging module, and connects the direct charging terminal of the direct charging module to the battery pack according to the direct charging connection signal to perform a direct charging operation on the battery pack. The balance charging control circuit generates a shutdown signal corresponding to the balance charging power conversion circuit, and shuts off the balance charging operation of the battery pack according to the shutdown signal corresponding to the balance charging power conversion circuit, and triggers the operation of generating a turn-on signal corresponding to the balance charging power conversion circuit when the current state of the battery pack is used to indicate that the charge of the battery in the battery pack meets a predetermined first charge condition.

4. The control method for balanced charging based on multi-winding magnetic coupling according to claim 3, characterized in that, The balancing charging control circuit detects the changes in the battery charge of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on the corresponding changes in the battery charge. The circuit also includes: When the current state of the battery pack is used to indicate that the charge of the battery in the battery pack meets a predetermined third charge condition, the balance charging control circuit generates an on signal for the equalization circuit and a first charging signal for the balance charging power conversion circuit, wherein the charge stored in the battery pack corresponding to the third charge condition is less than the charge stored in the battery pack corresponding to the second charge condition. The balance charging control circuit controls the balance circuit to turn on the balance charging power conversion circuit according to the turn-on signal of the balance circuit, and controls the balance charging power conversion circuit to perform a charging operation on the battery pack with a first charging current that matches the first charging signal according to the first charging signal of the balance charging power conversion circuit. The balance charging control circuit detects the third change in the battery pack's charge level, generates a second charging signal for the balance charging power conversion circuit based on the third change in the battery pack's charge level, increases the charging current of the balance charging power conversion circuit based on the second charging signal, and triggers the operation of monitoring the second change in the battery pack's charge level when the current state of the battery pack indicates that the charge level of the batteries in the battery pack meets a predetermined second charge level condition.

5. The control method for balanced charging based on multi-winding magnetic coupling according to claim 4, characterized in that, The method further includes: The balance charging control circuit determines whether the direct charging terminal of the direct charging module is disconnected from the battery pack. When the determination result is yes, it triggers the operation of detecting the third change in the battery pack's charge level. When the result is determined to be negative, the balance charging control circuit generates a first shutdown signal, and according to the first shutdown signal, disconnects the connection between the direct charging terminal of the direct charging module and the battery pack, and triggers the operation of detecting the third change in the battery pack's charge level.

6. The control method for balanced charging based on multi-winding magnetic coupling according to any one of claims 1-5, characterized in that, The method further includes: During the charging process of the battery pack based on the balance charging power conversion circuit, the balance charging control circuit detects the first voltage change of each battery in the battery pack and determines the voltage change type of the battery pack based on the first voltage change of each battery. When the voltage change type corresponding to the battery pack indicates that there is a first target battery in the battery pack whose voltage change meets a predetermined first current adjustment condition, the balance charging control circuit generates a first current control signal that matches the voltage change of the first target battery, and performs a reduction operation on the current charging current of the battery pack according to the first current control signal corresponding to the first target battery; after charging the first target battery with the reduced current charging current of the first target battery, when it is determined that the current voltage change of the first target battery meets a predetermined second current adjustment condition, a second current control signal that matches the voltage change of the first target battery is generated, and performs an increase operation on the current charging current of the battery pack according to the second current control signal corresponding to the first target battery; When the voltage change type corresponding to the battery pack is used to indicate that the voltage change of all batteries in the battery pack meets the predetermined second current regulation condition, the balance charging control circuit generates a duty cycle control signal that matches the voltage change of the battery pack, and performs a pulse width duty cycle reduction operation on the primary side corresponding to the balance charging power conversion circuit according to the duty cycle control signal, so as to reduce the current charging current of the battery pack.

7. The control method for balanced charging based on multi-winding magnetic coupling according to claim 1, characterized in that, The balancing circuit includes a discharge state active balancing module, wherein the balancing terminal of the discharge state active balancing module is electrically connected to the balancing terminal of the balancing charging power conversion circuit, and the charging terminal of the discharge state active balancing module is used to electrically connect to the battery pack; wherein the balancing terminal of the discharge state active balancing module is the balancing terminal of the balancing circuit, and the charging terminal of the discharge state active balancing module is the direct charging terminal of the balancing circuit. The balancing charging control circuit detects changes in the battery charge levels of the batteries in the battery pack, and controls the balancing circuit and the balancing charging power conversion circuit to perform balancing charging control operations on the battery pack based on these changes. The system also includes: When it is determined that there is a second target battery in the battery pack during the discharge process, whose current voltage is less than or equal to a predetermined voltage threshold or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold, the balance charging control circuit generates a discharge equalization signal corresponding to the second target battery and a shutdown signal corresponding to each remaining battery in the battery pack other than the second target battery. According to the discharge equalization signal, the discharge state active equalization module is turned on to connect the discharge state active equalization module to the balance charging power conversion circuit. At the same time, according to the shutdown signal corresponding to each remaining battery, the charging branch of that remaining battery is disconnected. During the balancing charge process for the second target battery, when the difference between the voltage of the second target battery and the average voltage of all the remaining batteries is less than or equal to a preset voltage difference, the balancing charge control circuit generates a shutdown signal corresponding to the second target battery. Based on the shutdown signal, the charging branch of the second target battery is disconnected, and the system re-determines whether there is a second target battery in the battery pack during the discharge process whose current voltage is less than or equal to a predetermined voltage threshold or whose current voltage change rate is greater than or equal to a predetermined voltage change threshold.

8. A control circuit for balanced charging based on multi-winding magnetic coupling, characterized in that, The control circuit is used to execute the control method for balanced charging based on multi-winding magnetic coupling as described in any one of claims 1-7, and the control circuit includes a balanced charging power conversion circuit, an equalization circuit, and a balanced charging control circuit, wherein: The equalization terminal of the balanced charging power conversion circuit is electrically connected to the equalization terminal of the equalization circuit, the controlled terminal of the balanced charging power conversion circuit is electrically connected to the first control terminal of the balanced charging control circuit, and the charging terminal of the balanced charging power conversion circuit is used to connect each battery in the battery pack through multi-winding magnetic coupling, and the number of all the batteries is greater than or equal to 2. The controlled terminal of the equalization circuit is electrically connected to the second control terminal of the equalization charging control circuit, the direct charging terminal of the equalization circuit is electrically connected to the battery pack, and the detection terminal of the equalization charging control circuit is electrically connected to the battery pack. The balance charging control circuit is used to detect the changes in the battery charge in the battery pack, and control the balancing circuit and the balance charging power conversion circuit to perform balance charging control operation on the battery pack according to the changes in the battery charge.

9. A balance charging control device, the balance charging control device comprising a device body and a control circuit for balance charging based on multi-winding magnetic coupling as described in claim 8, wherein the device body is used to house the control circuit, and the balance charging control device is used to execute the control method for balance charging based on multi-winding magnetic coupling as described in any one of claims 1-7.

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