Control method, circuit and device for balanced charging based on charge transfer

Abstract

The present invention relates to the technical field of battery balanced charging, and specifically discloses a control method, circuit, and device for balanced charging based on charge transfer. The balanced control circuit analyzes collected voltage change data of a battery pack and performs active balanced control on a power control circuit and a charge transfer control circuit, so that the power control circuit and the charge transfer control circuit perform active balanced charging on the batteries in the battery pack according to the voltage change data of the batteries in the battery pack, so that each battery in the battery pack maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby improving the available capacity of the battery pack and extending the service life of the battery pack, and reducing the occurrence of the barrel effect caused by battery series mismatch and the occurrence of thermal runaway caused by circulating current due to parallel mismatch, further improving the overall available capacity, overall performance, and extending the service life, which is conducive to improving the safety and reliability of the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of battery balanced charging, and in particular to a control method, circuit and device for balanced charging based on charge transfer. Background Art

[0002] Current battery systems for home and commercial energy storage are composed of multiple packs connected in series and parallel in various ways to achieve the required voltage and capacity. Each pack is composed of multiple batteries connected in series. Depending on the capacity and voltage, a different number of packs are connected in series to form a battery cluster. Multiple battery clusters are then combined to form a container with a capacity ranging from 100 kW to several MW. The number of battery cells is increasing, from dozens to hundreds or even hundreds of thousands, ranging from small capacities of 5 kW-h to large capacities of dozens of MW-h.

[0003] Currently, cell grouping is typically performed using an initial static balancing method, which uses the difference in ΔSOC capacity, ΔV voltage, and ΔR internal resistance between cells. However, in practice, this method fails to achieve precise grouping. Furthermore, after numerous cycles, the cell lifespan, self-discharge, internal gassing (externally manifested as a gradual increase in pressure per unit area of ​​the module), and active material SOC internal resistance become increasingly inconsistent. Furthermore, the currently widely used passive balancing current is only a few hundred milliamperes. For charge and discharge currents of several amperes, tens of amperes, or even thousands of amperes, this method is unable to maintain relatively consistent dynamic voltage and dynamic SOC across cells during use, resulting in a decrease in the available capacity and lifespan of the entire battery cabinet and battery cluster.

[0004] Therefore, it is particularly important to propose a new method for active balanced charging of battery packs so that each battery maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby increasing the available capacity of the battery and extending the battery life. Summary of the Invention

[0005] The present invention provides a control circuit for balanced charging based on charge transfer, which can actively balance charging of a battery pack so that each battery cell maintains relatively consistent dynamic voltage and dynamic SOC during use, thereby increasing the available capacity of the battery and extending the battery life.

[0006] In order to solve the above technical problems, the first aspect of the present invention discloses a control method for balanced charging based on charge transfer. The method is applied to a control circuit, which includes a balanced control circuit, a power control circuit, and a charge transfer control circuit, wherein:

[0007] The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to be electrically connected to a power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, the battery pack includes at least two batteries, and the batteries included in the battery pack are connected in series; the balancing end of the charge transfer control circuit is used to be electrically connected to the battery pack; and the detection end of the balancing control circuit is used to be electrically connected to the battery pack.

[0008] The method comprises:

[0009] The balancing control circuit collects voltage change data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack.

[0010] As an optional embodiment, in the first aspect of the present invention, the balancing control circuit controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack, including:

[0011] When the voltage change data of the batteries in the battery pack indicates that there is a first battery in the battery pack whose current voltage change meets a predetermined first balanced charging condition, the balancing control circuit reduces the charging current of the battery pack according to the current voltage change of the first battery; the current voltage of the first battery is greater than the current voltage of each of all batteries in the battery pack except the first battery; after reducing the charging current of the battery pack, the balancing control circuit controls the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; when the charge transfer condition corresponding to the first battery meets a predetermined charge transfer termination condition, the balancing control circuit controls the first battery to disconnect from the charge transfer control circuit so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the batteries in the battery pack except the first battery;

[0012] When the voltage change data of the batteries in the battery pack indicates that there is a second battery in the battery pack whose current voltage change meets a predetermined second equalizing charging condition, the equalizing control circuit selects the second battery from the batteries in the battery pack; the equalizing control circuit controls the charge transfer control circuit to disconnect the charge transfer control circuit from the battery pack, connect the power control circuit to the second battery, and disconnect the power control circuit from all batteries in the battery pack except the second battery; the equalizing control circuit controls the power control circuit to perform an equalizing charging operation on the second battery using the total voltage of the battery pack until the voltage of the charged second battery reaches a first preset voltage, wherein the current voltage of the second battery is less than the current voltage of each of all batteries in the battery pack except the second battery.

[0013] As an optional embodiment, in the first aspect of the present invention, the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the battery other than the first battery in the battery pack, including:

[0014] The balancing control circuit determines all third batteries that need to be charged from all batteries in the battery pack except the first battery;

[0015] The balancing control circuit controls the charge transfer control circuit so that all the third batteries are connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to all the third batteries at the same time; or, the balancing control circuit controls the charge transfer control circuit so that one of the third batteries is connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the third battery, and when the current voltage of the third battery reaches the second preset voltage corresponding to the third battery, controls the third battery to be disconnected from the charge transfer control circuit, and continues to perform the same charge transfer operation on the next third battery until the current voltage of all the third batteries reaches the corresponding second preset voltage.

[0016] As an optional embodiment, in the first aspect of the present invention, the method further comprises:

[0017] The balancing control circuit calculates a mean voltage corresponding to the battery pack according to the current voltage of each battery in the battery pack;

[0018] The balancing control circuit calculates the difference between the current voltage of the first battery and the mean voltage corresponding to the battery pack to obtain a difference voltage corresponding to the first battery;

[0019] The balancing control circuit determines the charge transfer end condition according to the differential voltage corresponding to the first battery.

[0020] As an optional embodiment, in the first aspect of the present invention, the method further comprises:

[0021] The balancing control circuit obtains the current voltage of the energy storage device of the charge transfer control circuit, and determines whether the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to a preset transfer voltage;

[0022] When it is determined that the voltage is greater than or equal to the preset transfer voltage, the balancing control circuit triggers the execution of the operation of controlling the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit;

[0023] When it is determined that the voltage is less than the preset transfer voltage, the balancing control circuit controls the power control circuit to perform a charging operation on the energy storage device of the charge transfer control circuit;

[0024] When the charging status of the energy storage device indicates that the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to the preset transfer voltage, performing the operation of controlling the charge transfer control circuit to be connected to the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit;

[0025] The method further comprises:

[0026] The balancing control circuit acquires a current voltage of each battery in all batteries except the first battery in the battery pack;

[0027] The balancing control circuit calculates an arithmetic mean of current voltages of all batteries in the battery pack except the first battery as the preset transfer voltage.

[0028] A second aspect of the present invention discloses a control circuit for balanced charging based on charge transfer, the control circuit comprising a balanced control circuit, a power control circuit, and a charge transfer control circuit, wherein:

[0029] The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to be electrically connected to a power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, the battery pack includes at least two batteries, and the batteries included in the battery pack are connected in series; the balancing end of the charge transfer control circuit is used to be electrically connected to the battery pack; and the detection end of the balancing control circuit is used to be electrically connected to the battery pack.

[0030] The balancing control circuit is configured to collect voltage change data of the batteries in the battery pack, and control the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack.

[0031] As an optional implementation, in the second aspect of the present invention, the power control circuit includes a power pre-charge control module, a first switch module, and a second switch module, wherein:

[0032] The first end of the power pre-charge control module is electrically connected to the first end of the first switch module, the second end of the power pre-charge control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charge control module is electrically connected to the balancing control circuit;

[0033] The second end of the first switch module is used to electrically connect to the battery pack, and the third end of the first switch module is used to electrically connect to the power supply module;

[0034] The second end of the second switch module is electrically connected to the bus terminal of the charge transfer control circuit, and the third end of the second switch module is electrically connected to the controlled end of the charge transfer control circuit;

[0035] Wherein, the bus terminal of the charge transfer control circuit and the controlled terminal of the charge transfer control circuit constitute the first controlled terminal of the charge transfer control circuit;

[0036] The power pre-charge control module is configured to control the first switch module, the second switch module and the charge transfer control circuit under the control of the balancing control circuit to perform a balancing charging operation on the batteries in the battery pack.

[0037] As an optional embodiment, in the second aspect of the present invention, the charge transfer control circuit includes a charge transfer control module, a balanced charge and discharge bus, and a plurality of switch groups;

[0038] The balanced charge and discharge busbar includes a first busbar and a second busbar, the number of all the switch groups is equal to the number of all the batteries in the battery pack; each battery in the battery pack has a one-to-one corresponding switch group;

[0039] The first controlled end of the charge transfer control module is electrically connected to the third end of the second switch module, the second controlled end of the charge transfer control module is electrically connected to the second control end of the balancing control circuit, the first transfer end of the charge transfer control module is electrically connected to one end of one of the switches in the switch group of each battery in the battery pack through the first bus, and the second transfer end of the charge transfer control module is electrically connected to one end of the other switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches in each switch group are electrically connected to the battery corresponding to the switch group;

[0040] The charge transfer control module is configured to perform a balanced charging operation on the batteries in the battery pack through the balanced charge and discharge bus and the plurality of switching switch groups under the control of the balanced control circuit and the power control circuit.

[0041] As an optional implementation, in the second aspect of the present invention, the charge transfer control circuit further includes a protection module;

[0042] The protection module includes a saturable inductor and a linear inductor connected in series with the saturable inductor; the saturable inductor and the linear inductor are connected in series between the first transfer terminal of the charge transfer control module and the first bus;

[0043] Wherein, the saturable inductor is used to suppress transient current spikes during the charging and discharging process of the charge transfer control circuit;

[0044] The linear inductor is used to suppress the RMS value of the current during the charging process of the charge transfer control circuit;

[0045] The charge transfer control circuit also includes a freewheeling absorption module;

[0046] The freewheeling absorption module is connected in parallel to the saturable inductor and the linear inductor, and one end of the freewheeling absorption module is electrically connected to the second transfer end of the charge transfer control module;

[0047] The freewheeling absorption module is used to absorb the energy stored in the saturable inductor and the linear inductor and release the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit.

[0048] A third aspect of the present invention discloses a balanced charging control device, comprising a device body and a control circuit for balanced charging based on charge transfer as described in any one of the second aspects, wherein the device body is used to house the control circuit, and the balanced charging control device is used to execute the control method for balanced charging based on charge transfer as described in any one of the first aspects.

[0049] The implementation of the present invention has the following beneficial effects:

[0050] The present invention provides a control method for balanced charging based on charge transfer, which is applied to a control circuit, wherein the control circuit includes a balanced control circuit, a power control circuit and a charge transfer control circuit, wherein the controlled end of the power control circuit is electrically connected to the first control end of the balanced control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balanced control circuit; the power receiving end of the power control circuit is used to be electrically connected to a power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, the battery pack includes at least two batteries, and each battery is connected in series; the balanced end of the charge transfer control circuit is used to be electrically connected to the battery pack; the detection end of the balanced control circuit is used to be electrically connected to the battery; wherein the balanced control circuit collects voltage change data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack, and performs balanced charging control operations on the batteries in the battery pack. It can be seen that the balancing control circuit of the present invention analyzes the collected voltage change data of the battery pack and actively performs balancing control on the power control circuit and the charge transfer control circuit, so that the power control circuit and the charge transfer control circuit perform active balancing charging on the batteries in the battery pack according to the voltage change data of the batteries in the battery pack, so that each battery in the battery pack maintains a relatively consistent dynamic voltage and dynamic SOC during use (including charging), thereby improving the available capacity of the battery pack and extending the service life of the battery pack, and reducing the occurrence of the barrel effect caused by battery series mismatch and the occurrence of thermal runaway caused by circulating current due to parallel mismatch, further improving the overall available capacity, overall performance and extending the service life, which is conducive to improving the safety and reliability of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 This is a schematic structural diagram of a control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention;

[0053] Figure 2 This is a flow chart of a control method for balanced charging based on charge transfer disclosed in an embodiment of the present invention;

[0054] Figure 3 1 is a schematic structural diagram of another control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention;

[0055] Figure 4 It is a structural diagram of a balanced charging control device disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0057] It should be noted that, unless otherwise expressly specified and limited, the term "electrical connection" in the specification and claims of the present invention and the above-mentioned drawings should be understood in a broad sense. For example, it can be 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 can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two elements or an interactive relationship between two elements. In addition, the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. The terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Furthermore, references to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0059] The present invention discloses a control method, circuit, and device for charge transfer-based equalization charging. The equalization control circuit analyzes collected voltage variation data from a battery pack and actively controls the power control circuit and the charge transfer control circuit. This allows the power control circuit and the charge transfer control circuit to perform active equalization charging on the batteries in the battery pack based on the voltage variation data. This ensures that each battery in the battery pack maintains a relatively consistent dynamic voltage and dynamic SOC during use (including charging). This increases the available capacity and extends the battery pack's service life. It also reduces the occurrence of the "barrel effect" caused by series battery mismatch and the occurrence of thermal runaway caused by circulating current due to parallel battery mismatch. This further increases the overall available capacity, overall performance, and service life, thereby enhancing the safety and reliability of the battery pack. These methods are described in detail below.

[0060] Example 1

[0061] See also Figure 1-3 , Figure 1 1 is a schematic structural diagram of a control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention. Figure 2 1 is a flow chart of a control method for balanced charging based on charge transfer disclosed in an embodiment of the present invention. Figure 3 This is a schematic diagram of another control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention. Figure 2 The method is applied in Figure 1 、 3 In the control circuit, the method and circuit are applicable to one of the batteries including but not limited to sodium ion battery, ternary lithium battery, lithium iron phosphate battery, etc. Figure 1 As shown, the control circuit includes a balancing control circuit, a power control circuit and a charge transfer control circuit, wherein:

[0062] The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to be electrically connected to the power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, and the battery pack includes at least two batteries, wherein the batteries included in the battery pack are connected in series; the balancing end of the charge transfer control circuit is used to be electrically connected to the battery pack; and the detection end of the balancing control circuit is used to be electrically connected to the battery pack.

[0063] like Figure 2 As shown, the control method for balanced charging based on charge transfer may include the following steps:

[0064] 101. The balancing control circuit collects voltage change data of the batteries in the battery pack.

[0065] 102. The balancing control circuit controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack, and performs a balancing charging control operation on the batteries in the battery pack.

[0066] It can be seen that implementation Figure 2 In the described method, the balancing control circuit analyzes the collected voltage change data of the battery pack and actively performs balancing control on the power control circuit and the charge transfer control circuit, so that the power control circuit and the charge transfer control circuit perform active balancing charging on the batteries in the battery pack according to the voltage change data of the batteries in the battery pack, so that the batteries in the battery pack maintain relatively consistent dynamic voltage and dynamic SOC during use (including charging), thereby improving the available capacity of the battery pack and extending the service life of the battery pack, and reducing the occurrence of the barrel effect caused by battery series mismatch and the occurrence of thermal runaway caused by circulating current due to parallel mismatch, further improving the overall available capacity, overall performance and extending the service life, which is conducive to improving the safety and reliability of the battery pack.

[0067] In the embodiment of the present invention, optionally, different power supply modules correspond to different situations of the battery pack. Specifically, when the battery pack is in a charging state, the power supply module can be a direct charging switch and a direct charging power change module. At this time, the power receiving end and the charging end of the power control circuit are different ends; when the battery pack is in a discharging state, the power supply module can be a battery pack. At this time, the power receiving end and the charging end of the power control circuit are the same end. Furthermore, the direct charging switch can be integrated into the direct charging power conversion module or can be independent of the direct charging power conversion module. Among them, when independent of the direct charging power conversion module, such as Figure 3 As shown, the balancing control circuit may include a control unit MCU, the controlled end of the direct-charging power conversion module and the controlled end of the direct-charging switch are electrically connected to the third control end and the fourth control end of the balancing control circuit (specifically, the control unit MCU), respectively, the power supply end of the direct-charging power conversion module is electrically connected to the power receiving end of the power control circuit and the switch end of the direct-charging switch at the same time, and the direct-charging end of the direct-charging switch is used to electrically connect the battery pack, specifically, to electrically connect the battery at the end point in the battery pack, and the other end of the battery at the other end point is grounded, or is grounded through the sampling resistor Rs. The direct-charging power conversion module is used to directly charge the batteries of the battery pack. Furthermore, it is also used to charge the energy storage device of the charge transfer control circuit.

[0068] In the embodiment of the present invention, Figure 3 As shown, the power control circuit includes a power pre-charge control module, a first switch module and a second switch module, wherein:

[0069] The first end of the power pre-charge control module is electrically connected to the first end of the first switch module, the second end of the power pre-charge control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charge control module is electrically connected to the balancing control circuit;

[0070] The second end of the first switch module is used to electrically connect to the battery pack, and further, the third end of the first switch module is used to electrically connect to the power supply module;

[0071] The second end of the second switch module is electrically connected to the bus terminal of the charge transfer control circuit, specifically Figure 3 The first bus in the second switch module, the third end of the second switch module is electrically connected to the controlled end of the charge transfer control circuit;

[0072] The bus terminal of the charge transfer control circuit and the controlled terminal of the charge transfer control circuit constitute a first controlled terminal of the charge transfer control circuit.

[0073] In the embodiment of the present invention, further optional, such as Figure 3 As shown, the charge transfer control circuit includes a charge transfer control module, a balanced charge and discharge bus, and multiple switch groups; wherein the balanced charge and discharge bus includes a first bus and a second bus, and the number of all switch groups is equal to the number of all batteries in the battery pack; each battery in the battery pack (or each sub-battery group, the batteries in each sub-battery group are connected in parallel) has a one-to-one corresponding switch group, such as Figure 3 As shown, the battery pack includes four batteries: BAT1, BAT2, BAT3, and BAT4. The corresponding switch groups for batteries BAT1, BAT2, BAT3, and BAT4 are SW11 and SW12, SW21 and SW22, SW31 and SW32, and SW41 and SW42. Any switch group can be, but is not limited to, a MOS transistor (e.g., conduction loss Pd = I² × Rdson), a relay, a DC switch, or a triode, as long as it can connect and disconnect the corresponding branch. Among them, the first controlled end of the charge transfer control module is electrically connected to the third end of the second switch module, the second controlled end of the charge transfer control module is electrically connected to the second control end of the balancing control circuit, the first transfer end of the charge transfer control module is electrically connected to one end of one of the switches in the switch group of each battery in the battery pack through the first bus, and the second transfer end of the charge transfer control module is electrically connected to one end of the other switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches in each switch group are electrically connected to the battery corresponding to the switch group.

[0074] In an embodiment of the present invention, optionally, the balancing control circuit controls the power control circuit and the charge transfer control circuit according to voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack, including:

[0075] When the voltage change data of the batteries in the battery pack indicates that there is a first battery in the battery pack whose current voltage change condition satisfies a predetermined first balancing charging condition, the balancing control circuit reduces the charging current of the battery pack according to the current voltage change condition of the first battery; the current voltage of the first battery is greater than the current voltage of each of the batteries in the battery pack except the first battery; after reducing the charging current of the battery pack, the balancing control circuit controls the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; when the charge transfer condition corresponding to the first battery satisfies a predetermined charge transfer termination condition, the balancing control circuit controls the first battery to disconnect from the charge transfer control circuit so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the batteries in the battery pack except the first battery;

[0076] When the voltage change data of the batteries in the battery pack indicates that a second battery exists in the battery pack whose current voltage change satisfies a predetermined second equalizing charging condition, the equalizing control circuit selects the second battery from the batteries in the battery pack; the equalizing control circuit controls the charge transfer control circuit to disconnect the charge transfer control circuit from the battery pack, connect the power control circuit to the second battery, and disconnect the power control circuit from all batteries in the battery pack except the second battery; and the equalizing control circuit controls the power control circuit to perform an equalizing charging operation on the second battery using the total voltage of the battery pack until the voltage of the charged second battery reaches a first preset voltage, wherein the current voltage of the second battery is less than the current voltage of each of all batteries in the battery pack except the second battery.

[0077] In an embodiment of the present invention, the balancing control circuit optionally detects voltage change data of batteries in the battery pack. When the voltage change data of the batteries in the battery pack indicates that there is a first battery in the battery pack whose difference between a current voltage and the current voltage of each remaining battery in the battery pack is greater than or equal to a first balancing start voltage (e.g., 20 mV), or there is a first battery whose voltage rise rate is greater than or equal to a first balancing voltage rise rate (e.g., 60%), it indicates that there is a first battery in the battery pack whose current voltage change condition meets a predetermined first balancing charging condition.

[0078] In an embodiment of the present invention, optionally, the purpose of reducing the charging current of the battery pack can be achieved by reducing the current total charging current of the battery pack (such as reducing it to 5%-10%) or directly shutting down the current total charging current, so that the first battery fails to achieve the expected voltage reduction effect and the other batteries in the battery pack also fail to achieve the expected voltage boost effect.

[0079] In an embodiment of the present invention, the balancing control circuit optionally detects voltage change data of batteries in the battery pack. When the voltage change data of the batteries in the battery pack indicates that there is a second battery in the battery pack whose current voltage difference with the current voltage of each remaining battery in the battery pack is less than or equal to a second balancing start voltage (e.g., 15 mV), or when there is a second battery whose voltage drop rate is greater than or equal to a second balancing voltage drop rate (e.g., 40%), it indicates that there is a second battery in the battery pack whose current voltage change meets a predetermined second balancing charging condition.

[0080] In an embodiment of the present invention, specifically, the balancing control circuit controls the switch groups SW11 and SW12 corresponding to the first battery (using BAT1 as an example) to close, thereby connecting the charge transfer control module to the first battery, thereby transferring the charge of the first battery to the energy storage device of the charge transfer control module. When the charge transfer corresponding to the first battery meets the charge transfer termination condition, the balancing control circuit controls the switch groups SW11 and SW12 to open, disconnecting the first battery from the charge transfer control module, and stopping the first battery from transferring charge to the energy storage device of the charge transfer control module. Optionally, the energy storage device can be a supercapacitor, a conventional capacitor (such as an electrolytic capacitor, a ceramic capacitor, a CBB capacitor, etc.), a battery (such as a solid-state battery, a solid-liquid hybrid battery, a liquid battery of various current materials, etc.), or an energy storage device of a certain material or method in the future, as long as it can serve as an energy relay.

[0081] In the embodiment of the present invention, further optionally, the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to batteries other than the first battery in the battery pack, including:

[0082] The balancing control circuit determines all third batteries that need to be charged from all batteries in the battery pack except the first battery;

[0083] The balancing control circuit controls the charge transfer control circuit so that all third batteries are connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to all third batteries simultaneously. Alternatively, the balancing control circuit controls the charge transfer control circuit so that one of the third batteries is connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the third battery. When the current voltage of the third battery reaches the second preset voltage corresponding to the third battery, the third battery is disconnected from the charge transfer control circuit, and the same charge transfer operation is continued for the next third battery until the current voltages of all third batteries reach the corresponding second preset voltage.

[0084] In the embodiment of the present invention, optionally, all the third batteries may be all batteries in the battery pack except the first battery, or may be part of the batteries, preferably all the batteries.

[0085] In the embodiment of the present invention, specifically, Figure 3 Taking the low-voltage batteries BAT2, BAT3, and BAT4 as an example, the control unit MCU simultaneously controls the switch groups SW21 and SW22, SW31 and SW32, and SW41 and SW42 corresponding to each of the third batteries BAT2, BAT3, and BAT4, so that the charge transfer control module is simultaneously connected to each of the third batteries, thereby simultaneously transferring the charge in the energy storage device of the charge transfer control module to all of the third batteries, so that each of the third batteries can obtain the corresponding amount of electricity, that is, reach the corresponding second preset voltage. Alternatively, the control unit MCU first controls the switch groups SW21 and SW22 corresponding to the third battery BAT2 to close, so that the charge transfer control module is first connected to the third battery BAT2, thereby transferring the charge in the energy storage device of the charge transfer control module to the third battery BAT2. After the third battery BAT2 reaches the corresponding second preset voltage, the control unit MCU controls the switch groups SW21 and SW22 to open, so that the charge transfer control module is first disconnected from the third battery BAT2, and charge is transferred to the third batteries BAT3 and BAT4 in the same manner to obtain the corresponding second preset voltage.

[0086] It should be noted that when the current voltage of all third batteries reaches the corresponding second preset voltage, the balancing control circuit continues to control the direct charging power conversion module and the direct charging switch to charge the battery pack, and so on. When the current voltage of the second battery reaches the corresponding second preset voltage, the balancing control circuit controls the power control circuit to turn off to stop charging the second battery, so that the battery pack continues to perform the discharge process, and so on. The cycle is carried out to achieve active balanced charging.

[0087] It can be seen that this optional embodiment enriches the charge transfer method and the circuit function by providing simultaneous charge transfer to low-voltage batteries, or performing charge transfer individually and sequentially; and improves the overall charge transfer efficiency by simultaneously transferring charge to low-voltage batteries, or improves the overall charge transfer stability and reliability by performing charge transfer individually and sequentially.

[0088] In an optional embodiment, the method may further include the following steps:

[0089] The balancing control circuit calculates the mean voltage corresponding to the battery pack based on the current voltage of each battery in the battery pack;

[0090] The balancing control circuit calculates the difference between the current voltage of the first battery and the mean voltage corresponding to the battery group to obtain the difference voltage corresponding to the first battery;

[0091] The balancing control circuit determines a charge transfer termination condition according to the differential voltage corresponding to the first battery.

[0092] In this optional embodiment, specifically, Figure 3 The battery pack shown contains four batteries: BAT1, BAT2, BAT3, and BAT4. The charge transfer termination condition is determined using the current voltages of BAT1, BAT2, BAT3, and BAT4 as examples. Theoretically, after active balancing charging, the voltage of each battery should be equal, specifically, Ux = (Ua + Ub + Uc + Ud) / 4. For battery BAT1, the required discharge voltage is ΔVa = Ua - Ux. ΔVa of battery BAT1 can be used directly as the charge transfer termination condition. That is, if the voltage corresponding to the charge discharged by battery BAT1 reaches ΔVa, the charge transfer termination condition is met. Alternatively, ΔVa of battery BAT1 can be multiplied by a voltage coefficient, such as 1.2. That is, if the voltage corresponding to the charge discharged by battery BAT1 reaches 1.2*ΔVa, the charge transfer termination condition is met.

[0093] In this optional embodiment, the required charging voltages for batteries BAT2, BAT3, and BAT4 are ΔVb = Ux - Ub, ΔVc = Ux - Uc, and ΔVd = Ux - Ud, respectively. Based on the high-voltage battery discharge voltage, the low-voltage battery charge voltage, the preset discharge and charge currents I, and the duration T, the capacity of the energy storage device required for charging battery BAT2 is Cb = IT / ΔVb, the capacity of the energy storage device required for charging battery BAT3 is Cc = IT / ΔVc, and the capacity of the energy storage device required for charging battery BAT4 is Cd = IT / ΔVd. The total capacity is Cx = Cb + Cc + Cd. The best case scenario is that the energy storage device capacities required for all three batteries are the same, i.e., Cx = 3Cc. However, considering the conduction loss of the main switch of the charge-discharge balancing bus (i.e., the switching switch group corresponding to the battery), especially the MOS tube, as well as the resistive loss of the charge-discharge balancing bus and the loss of the equivalent series resistance of the energy storage device, especially the capacitor type, the total capacity Cx needs to be multiplied by a preset capacity factor, such as 1.2. That is, the charge that needs to be transferred from the energy storage device of the charge transfer control module is at least the total charge capacity Cx required by all low-voltage batteries multiplied by the preset capacity factor, such as 1.2*Cx.

[0094] It can be seen that this optional embodiment can improve the accuracy and efficiency of the charge transfer termination conditions by comprehensively analyzing the current voltage of the high-voltage battery and the current voltage of the low-voltage battery in the battery pack to determine the charge transfer termination conditions of the high-voltage battery, thereby helping to improve the accuracy and efficiency of the charge required to be transferred from the high-voltage battery, and further helping to improve the probability of each battery in the battery pack maintaining a relatively consistent dynamic voltage and dynamic SOC during use (including charging).

[0095] In another optional embodiment, the method may further include the following steps:

[0096] The balancing control circuit obtains attribute parameters of target components, wherein the target components include one or more of a charge-discharge balancing busbar, a switching switch group, and an energy storage device; wherein the attribute parameters of the charge-discharge balancing busbar include material and / or length, the attribute parameters of the switching switch group include the type of the switching switch group, and the attribute parameters of the energy storage device include the type of the energy storage device and circuit structure composition (such as a capacitor and a resistor connected in parallel with it, and an inductor and a resistor connected in series with it). wherein, for a detailed description of the type of the switching switch group and the type of the energy storage device, please refer to the relevant description elsewhere in the present invention;

[0097] The balancing control circuit obtains the usage time of each target component and estimates the charge loss caused by the charge transfer for each target component based on the usage time and corresponding property parameters. Different property parameters result in different degrees of charge loss caused by charge transfer. For example, supercapacitors have less charge loss caused by charge transfer than ordinary capacitors. Furthermore, the longer the usage time, the greater the charge loss caused by charge transfer.

[0098] The balancing control circuit determines a preset capacity factor based on the charge loss of all target components. The greater the charge loss, the larger the corresponding preset capacity factor, indicating that more charge needs to be transferred from the energy storage device. Furthermore, the preset transfer voltage will also increase to accommodate the increase in charge loss.

[0099] It can be seen that this optional embodiment analyzes the charge loss generated during the charge transfer process by combining the attribute parameters of the charge-discharge balancing bus, the energy storage device, and the switching switch group and their usage time, and has determined the corresponding preset capacity coefficient, thereby improving the analysis accuracy and reliability of the preset capacity coefficient, thereby facilitating further improving the accuracy of charge transfer from the energy storage device to the low-voltage battery, and further facilitating further improving the consistency of dynamic charge between the batteries in the battery pack.

[0100] In another optional embodiment, the method may further include the following steps:

[0101] The balancing control circuit obtains the current voltage of the energy storage device of the charge transfer control circuit, and determines whether the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to the preset transfer voltage;

[0102] When it is determined that the voltage is greater than or equal to the preset transfer voltage, the balancing control circuit triggers the execution of the above-mentioned operation of controlling the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit;

[0103] When it is determined that the voltage is less than the preset transfer voltage, the balancing control circuit controls the power control circuit to perform a charging operation on the energy storage device of the charge transfer control circuit;

[0104] When the charging condition of the energy storage device is used to indicate that the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to the preset transfer voltage, the above-mentioned operation of controlling the charge transfer control circuit to be connected to the first battery is performed so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit.

[0105] In this optional embodiment, specifically, the balancing control circuit controls the first end of the first switch module to contact the third end of the first switch module, and controls the second end of the second switch module to contact the third end of the second switch module; after both are in contact, the balancing control circuit controls the power pre-charge control module to transfer the voltage of the power supply module to charge the energy storage device of the charge transfer control circuit through the first switch module and the second switch module until the current voltage of the energy storage device is greater than or equal to the preset transfer voltage. Furthermore, during the charging process of the energy storage device, a PWM method can be used to reduce the average charging current of the energy storage device, thereby reducing the average current stress on the switching switch group corresponding to the battery pack during the charging time, protecting the switching switch group from damage.

[0106] As can be seen, this optional embodiment analyzes the current voltage (charge) in the energy storage device before transferring the charge of the high-voltage battery to the energy storage device of the charge transfer control circuit. If the current voltage (charge) is greater than or equal to the preset transfer voltage, the subsequent charge transfer operation continues. If not, the energy storage device is charged based on the power control circuit and the charge transfer control circuit, and the high-voltage battery is connected again for charge transfer when the current voltage is greater than or equal to the preset transfer voltage. This ensures that charge transfer can be performed when the voltage difference between the energy storage device and the high-voltage battery is relatively small, reducing the current, improving the safety of charge transfer from the high-voltage battery, and reducing the possibility of component damage. This is especially true for capacitor-type energy storage devices, whose inherent physical characteristic is that the voltage across the two ends cannot suddenly change. If the high-voltage battery directly charges the energy storage device with an initial voltage of zero, it will generate an extremely large peak current, which will damage the switching switch group, thereby causing the high-voltage battery to discharge rapidly at an ultra-high rate and damage the battery. In addition, the saturable inductor and linear inductor in the charge transfer control module are used to suppress the current, further reducing the circuit current and further improving the safety of charge transfer.

[0107] In another optional embodiment, the method may further include the following steps:

[0108] The balancing control circuit obtains a current voltage of each battery in all batteries except the first battery in the battery pack;

[0109] The balancing control circuit calculates an arithmetic average of the current voltages of all batteries except the first battery in the battery pack as a preset transfer voltage.

[0110] In this optional embodiment, the preset transfer voltage can optionally be the arithmetic mean of the voltages of all low-voltage batteries in the battery pack at the current moment, such as (Ub + Uc + Ud) / 3, or it can be greater than this voltage arithmetic mean. Furthermore, during the charging process of the energy storage device, the arithmetic mean of the voltages of all low-voltage batteries in the battery pack is constantly monitored and tracked, and can be kept consistent with this voltage arithmetic mean. This allows the high-voltage battery to charge the energy storage device at a much lower current when the equalization circuit activates due to a large voltage difference. This, combined with the linear inductor and saturable inductor connected in series with the charge transfer control module, reduces the rate of change of the supercapacitor's charge and discharge current during the rising phase.

[0111] It can be seen that this optional embodiment improves the accuracy and reliability of determining the preset transfer voltage by detecting the momentary voltages of all low-voltage batteries and determining the preset transfer voltage based on the arithmetic mean of the momentary voltages, thereby facilitating further improving the accuracy and safety of transferring the charge in the high-voltage battery to the energy storage device.

[0112] In another optional embodiment, the charge transfer control circuit may further include a protection module; wherein, Figure 3 As shown, the protection module includes a saturable inductor and a linear inductor connected in series with the saturable inductor; the saturable inductor and the linear inductor are connected in series between the first transfer terminal and the first bus of the charge transfer control module; wherein the saturable inductor is used to suppress transient current spikes during the charging and discharging process of the charge transfer control circuit; and the linear inductor is used to suppress the root mean square value of the current during the charging process of the charge transfer control circuit.

[0113] It can be seen that this optional embodiment can suppress the transient current spikes during the charging and discharging process of the charge transfer control circuit and suppress the root mean square value of the current during the charging process of the charge transfer control circuit by setting a saturable inductor and a linear inductor between the charge transfer control module and the bus, so as to reduce the damage to the charge transfer control module caused by the transient current spikes during the charging and discharging process, and make the current smoother during the charging and discharging process, thereby improving the efficiency and stability of the charge transfer and protecting the components in the circuit.

[0114] In another optional embodiment, Figure 3As shown, the charge transfer control circuit may further include a freewheeling absorption module; wherein the freewheeling absorption module is connected in parallel to the saturable inductor and the linear inductor, and one end of the freewheeling absorption module is electrically connected to the second transfer end of the charge transfer control module; wherein the freewheeling absorption module is used to absorb the energy stored in the saturable inductor and the linear inductor while releasing the energy to the battery pack or the energy storage device of the charge transfer control circuit. The freewheeling absorption module may be composed of one or more of a freewheeling diode, an RC absorption circuit, a transient voltage suppressor diode, and a varistor, as long as it can absorb the energy stored in the saturable inductor and the linear inductor while releasing the energy to the battery pack or the energy storage device of the charge transfer control circuit.

[0115] It can be seen that this optional embodiment, by setting a freewheeling absorption module between the charge transfer control module and the busbar and connecting it in parallel with the protection module, absorbs the energy stored in the saturable inductance and the linear inductance and releases the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit, thereby reducing the occurrence of high voltage damage to the switching switch corresponding to the battery due to nowhere to release the energy, and improving the reliability and success probability of active equalization charging in the charging state of the battery pack.

[0116] In another optional embodiment, Figure 3 As shown, the balancing control circuit may further include a feedback loop, wherein the connection relationship between the control unit MCU and the communication end of the feedback loop and other circuits may be as follows: Figure 3 As shown. Furthermore, the control unit MCU can detect the charging current of the battery pack by measuring the voltage across the sampling resistor Rs. Further optionally, the control circuit can also be a temperature detection circuit, wherein the temperature detection circuit includes multiple temperature detection modules, wherein each temperature detection module corresponds to a battery (or a sub-battery group, the batteries of the sub-battery group are connected in parallel), and is used to detect the temperature of the corresponding battery during the charging or discharging process. Optionally, the temperature detection module specifically corresponds to Figure 3The temperature sensor in the battery pack is fed back to the control unit MCU, which controls the charge transfer control module, the switching switch group, the second switch module, the first switch module, and (or through the feedback loop) the power pre-charge control module to perform active equalization charging on the batteries in the battery pack. If the detected battery temperature is greater than or equal to a preset temperature, the active equalization charging operation is stopped. When the detected battery temperature is less than the preset temperature, the active equalization charging operation is continued. In this way, by providing corresponding temperature sensors for the batteries in the battery pack to detect the temperature of the battery pack cells during the charging and discharging process, and stopping or continuing the charging or active equalization charging operation of the battery pack based on the temperature detection result, the charging and discharging of the battery pack and the active equalization charging during the charging and discharging process are achieved, while reducing damage to components caused by excessive temperature, thereby protecting the electronic components in the circuit.

[0117] It should be noted that the discharge and charge processes of the batteries in a battery pack are interchangeable. The series connection of the batteries in a battery pack can be understood as the series connection of all batteries in the battery pack, or as the series connection of multiple sub-battery packs, where the batteries in each sub-battery pack are connected in parallel. The larger the capacity of a single battery or the more batteries in a sub-battery pack are connected in parallel, the larger the capacity of the energy storage device required. Figure 3 The present technical solution is explained by taking a battery pack consisting of 4 batteries as an example, that is, the present technical solution is not limited to 4 batteries (electronic groups), but can also be 2 batteries (electronic groups), 6 batteries (electronic groups), 24 batteries (electronic groups), etc., without limitation. Among them, for each additional battery, a switching switch group and a corresponding temperature detection module are added.

[0118] Example 2

[0119] The embodiment of the present invention discloses a control circuit for balanced charging based on charge transfer, such as Figure 1 As shown, the control circuit includes a balancing control circuit, a power control circuit and a charge transfer control circuit, wherein:

[0120] The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to electrically connect to the power supply module, and the charging end of the power control circuit is used to electrically connect to the battery pack, which includes at least two batteries, and each battery is connected in series; the balancing end of the charge transfer control circuit is used to electrically connect to the battery pack; and the detection end of the balancing control circuit is used to electrically connect to the battery.

[0121] Among them, the balancing control circuit is used to collect voltage change data of the batteries in the battery pack, and control the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform balanced charging control operations on the batteries in the battery pack.

[0122] In the embodiment of the present invention, optionally, Figure 3 FIG. 1 is a schematic diagram of another control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention. Figure 3 As shown, the balancing control circuit may be a control unit MCU, and the power control circuit includes a power pre-charge control module, a first switch module, and a second switch module, wherein:

[0123] The first end of the power pre-charge control module is electrically connected to the first end of the first switch module, the second end of the power pre-charge control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charge control module is electrically connected to the balancing control circuit;

[0124] The second end of the first switch module is used to electrically connect to the battery pack, and further, the third end of the first switch module is used to electrically connect to the power supply module;

[0125] The second end of the second switch module is electrically connected to the bus terminal of the charge transfer control circuit, specifically Figure 3 The first bus in the second switch module, the third end of the second switch module is electrically connected to the controlled end of the charge transfer control circuit;

[0126] Wherein, the bus terminal of the charge transfer control circuit and the controlled terminal of the charge transfer control circuit constitute a first controlled terminal of the charge transfer control circuit;

[0127] The power pre-charge control module is used to control the first switch module, the second switch module and the charge transfer control circuit under the control of the balancing control circuit to perform a balancing charging operation on the batteries in the battery pack.

[0128] In the embodiment of the present invention, further optional, such as Figure 3 As shown, the charge transfer control circuit includes a charge transfer control module, a balanced charge and discharge bus, and multiple switch groups; wherein the balanced charge and discharge bus includes a first bus and a second bus, and the number of all switch groups is equal to the number of all batteries in the battery pack; each battery in the battery pack has a one-to-one corresponding switch group, such as Figure 3 As shown, the battery pack includes four batteries BAT1, BAT2, BAT3, and BAT4. The switching switch groups corresponding to the batteries BAT1, BAT2, BAT3, and BAT4 are SW11 and SW12, SW21 and SW22, SW31 and SW32, and SW41 and SW42.

[0129] The first controlled end of the charge transfer control module is electrically connected to the third end of the second switch module, the second controlled end of the charge transfer control module is electrically connected to the second control end of the balancing control circuit, the first transfer end of the charge transfer control module is electrically connected to one end of one of the switches in the switch group of each battery in the battery pack via the first bus, and the second transfer end of the charge transfer control module is electrically connected to one end of the other switch in the switch group of each battery in the battery pack via the second bus; the other ends of the two switches in each switch group are electrically connected to the battery corresponding to the switch group;

[0130] Among them, the charge transfer control module is used to perform balanced charging operations on the batteries in the battery pack through the balanced charge and discharge bus and multiple switching switch groups under the control of the balanced control circuit and the power control circuit.

[0131] In an optional embodiment, if Figure 3 As shown, the charge transfer control circuit may further include a protection module;

[0132] The protection module includes a saturable inductor and a linear inductor connected in series with the saturable inductor; the saturable inductor and the linear inductor are connected in series between the first transfer terminal of the charge transfer control module and the first bus;

[0133] Among them, the saturable inductor is used to suppress the transient current spike during the charging and discharging process of the charge transfer control circuit; the linear inductor is used to suppress the root mean square value of the current during the charging process of the charge transfer control circuit.

[0134] It can be seen that this optional embodiment can suppress the transient current spikes during the charging and discharging process of the charge transfer control circuit and suppress the root mean square value of the current during the charging process of the charge transfer control circuit by setting a saturable inductor and a linear inductor between the charge transfer control module and the bus, so as to reduce the damage to the charge transfer control module caused by the transient current spikes during the charging and discharging process, and make the current smoother during the charging and discharging process, thereby improving the efficiency and stability of the charge transfer and protecting the components in the circuit.

[0135] In another optional embodiment, the charge transfer control circuit may further include a freewheeling absorption module;

[0136] The freewheeling absorption module is connected in parallel to the saturable inductor and the linear inductor, and one end of the freewheeling absorption module is electrically connected to the second transfer end of the charge transfer control module;

[0137] Among them, the freewheeling absorption module is used to absorb the energy stored in the saturable inductor and the linear inductor and release the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit.

[0138] It can be seen that this optional embodiment, by setting a freewheeling absorption module between the charge transfer control module and the busbar and connecting it in parallel with the protection module, absorbs the energy stored in the saturable inductance and the linear inductance and releases the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit, thereby reducing the occurrence of high voltage damage to the switching switch corresponding to the battery due to nowhere to release the energy, and improving the reliability and success probability of active equalization charging in the charging state of the battery pack.

[0139] In the embodiment of the present invention, Figure 3 As shown, the balancing control circuit can be a control unit MCU, and can also include a feedback loop, wherein the connection relationship between the control unit MCU and the communication end of the feedback loop and other circuits can be as follows Figure 3 As shown, further, the charging current detection of the battery pack can be achieved by measuring the voltage across the sampling resistor Rs. Further optionally, the control circuit can also be a temperature detection circuit, wherein the temperature detection circuit includes multiple temperature detection modules, wherein each temperature detection module corresponds to a battery, and is used to detect the temperature of the corresponding battery during the charging or discharging process, specifically corresponding to Figure 3 The temperature sensor in the battery pack is fed back to the control unit MCU, which controls the charge transfer control module, the switching switch group, the second switch module, the first switch module, and (or through a feedback loop) the power pre-charge control module to perform active balancing charging on the batteries in the battery pack. If the detected battery temperature is greater than or equal to a preset temperature, the active balancing charging operation is stopped. When the detected battery temperature is less than the preset temperature, the active balancing charging operation is continued. In this way, by providing corresponding temperature sensors for the batteries in the battery pack to detect the temperature of the battery pack cells during charging and discharging, and stopping or continuing the active balancing charging operation based on the temperature detection results, the active balancing charging operation is reduced while achieving active balancing charging during the charging and discharging of the battery pack and during the charging and discharging process, thereby protecting the electronic components in the circuit.

[0140] Example 3

[0141] See also Figure 4 As shown, Figure 4 This is a structural diagram of a balanced charging control device disclosed in an embodiment of the present invention. The balanced charging control device can actively balance charge the battery pack when it is in a charging state or when it is in a discharging state. The balanced charging control device includes a device body and a control circuit, wherein the control circuit is as follows: Figure 1 and Figure 3 The circuit described, and the device body is used to place the control circuit, and is used to execute the control method for balanced charging based on charge transfer as described in embodiment 1.

[0142] It should be noted that for a detailed description of the control circuit for balanced charging based on charge transfer and a detailed description of the control method for balanced charging based on charge transfer, please refer to the specific description of the relevant contents in the first and second embodiments, which will not be repeated in this embodiment.

[0143] It can be seen that implementation Figure 4 The described balanced charging control device can actively perform balanced control on the power control circuit and the charge transfer control circuit based on the balanced control circuit set therein by analyzing the collected voltage change data of the battery pack, so that the power control circuit and the charge transfer control circuit perform active balanced charging on the batteries in the battery pack according to the voltage change data of the batteries in the battery pack, so that the batteries in the battery pack maintain relatively consistent dynamic voltage and dynamic SOC during use (including charging), thereby improving the available capacity of the battery pack and extending the service life of the battery pack, and reducing the occurrence of the barrel effect caused by battery series mismatch and the occurrence of thermal runaway caused by circulating current due to parallel mismatch, further improving the overall available capacity, overall performance and extending the service life, which is conducive to improving the safety and reliability of the battery pack.

[0144] The above describes in detail a control method, circuit, and device for balanced charging based on charge transfer disclosed in an embodiment of the present invention. Specific embodiments are used herein to illustrate the principles and implementation methods of the present invention. However, the preferred embodiments are not intended to limit the present invention. The description of the above embodiments is only intended to help understand the method and core concept of the present invention. At the same time, for those skilled in the art, based on the concept of the present invention, changes may be made in the specific implementation methods and application scopes without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. A control method for balanced charging based on charge transfer, characterized in that: The method is applied to a control circuit, which includes a balancing control circuit, a power control circuit, and a charge transfer control circuit, wherein: The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to be electrically connected to a power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, the battery pack includes at least two batteries, and the batteries included in the battery pack are connected in series; the balancing end of the charge transfer control circuit is used to be electrically connected to the battery pack; and the detection end of the balancing control circuit is used to be electrically connected to the battery pack. The method comprises: The balancing control circuit collects voltage change data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack; The balancing control circuit controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack, including: When the voltage change data of the batteries in the battery pack indicates that there is a first battery in the battery pack whose current voltage change meets a predetermined first balanced charging condition, the balancing control circuit reduces the charging current of the battery pack according to the current voltage change of the first battery; the current voltage of the first battery is greater than the current voltage of each of all batteries in the battery pack except the first battery; after reducing the charging current of the battery pack, the balancing control circuit controls the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; when the charge transfer condition corresponding to the first battery meets a predetermined charge transfer termination condition, the balancing control circuit controls the first battery to disconnect from the charge transfer control circuit so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the batteries in the battery pack except the first battery; The first battery that meets the first balanced charging condition includes a battery in the battery pack having a voltage difference between its current voltage and the current voltage of each remaining battery in the battery pack that is greater than or equal to a first balanced starting voltage, or a battery having a voltage rise rate that is greater than or equal to a first balanced voltage rise rate.

2. The control method for balanced charging based on charge transfer according to claim 1, characterized in that: The balancing control circuit controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charge control operation on the batteries in the battery pack, and further includes: When the voltage change data of the batteries in the battery pack indicates that a second battery exists in the battery pack whose current voltage change satisfies a predetermined second equalizing charging condition, the equalizing control circuit selects the second battery from the batteries in the battery pack; the equalizing control circuit controls the charge transfer control circuit to disconnect the charge transfer control circuit from the battery pack, connect the power control circuit to the second battery, and disconnect the power control circuit from all batteries in the battery pack except the second battery; the equalizing control circuit controls the power control circuit to perform an equalizing charging operation on the second battery using the total voltage of the battery pack until the voltage of the second battery after charging reaches a first preset voltage; wherein the current voltage of the second battery is less than the current voltage of each of all batteries in the battery pack except the second battery.

3. The control method for balanced charging based on charge transfer according to claim 2, characterized in that: The balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the batteries in the battery pack except the first battery, including: The balancing control circuit determines all third batteries that need to be charged from all batteries in the battery pack except the first battery; The balancing control circuit controls the charge transfer control circuit so that all the third batteries are connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to all the third batteries at the same time; or, the balancing control circuit controls the charge transfer control circuit so that one of the third batteries is connected to the charge transfer control circuit, and controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the third battery, and when the current voltage of the third battery reaches the second preset voltage corresponding to the third battery, controls the third battery to be disconnected from the charge transfer control circuit, and continues to perform the same charge transfer operation on the next third battery until the current voltage of all the third batteries reaches the corresponding second preset voltage.

4. The control method for balanced charging based on charge transfer according to claim 2 or 3, characterized in that: The method further comprises: The balancing control circuit calculates a mean voltage corresponding to the battery pack according to the current voltage of each battery in the battery pack; The balancing control circuit calculates the difference between the current voltage of the first battery and the mean voltage corresponding to the battery pack to obtain a difference voltage corresponding to the first battery; The balancing control circuit determines the charge transfer end condition according to the differential voltage corresponding to the first battery.

5. The control method for balanced charging based on charge transfer according to claim 4, characterized in that: The method further comprises: The balancing control circuit obtains the current voltage of the energy storage device of the charge transfer control circuit, and determines whether the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to a preset transfer voltage; When it is determined that the voltage is greater than or equal to the preset transfer voltage, the balancing control circuit triggers the execution of the operation of controlling the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; When it is determined that the voltage is less than the preset transfer voltage, the balancing control circuit controls the power control circuit to perform a charging operation on the energy storage device of the charge transfer control circuit; When the charging status of the energy storage device indicates that the current voltage of the energy storage device of the charge transfer control circuit is greater than or equal to the preset transfer voltage, performing the operation of controlling the charge transfer control circuit to be connected to the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; The method further comprises: The balancing control circuit acquires a current voltage of each battery in all batteries except the first battery in the battery pack; The balancing control circuit calculates an arithmetic mean of current voltages of all batteries in the battery pack except the first battery as the preset transfer voltage.

6. A control circuit for balanced charging based on charge transfer, characterized in that: The control circuit includes a balancing control circuit, a power control circuit and a charge transfer control circuit, wherein: The controlled end of the power control circuit is electrically connected to the first control end of the balancing control circuit, and the control end of the power control circuit is electrically connected to the first controlled end of the charge transfer control circuit; the second controlled end of the charge transfer control circuit is electrically connected to the second control end of the balancing control circuit; the power receiving end of the power control circuit is used to be electrically connected to a power supply module; the charging end of the power control circuit is used to be electrically connected to a battery pack, the battery pack includes at least two batteries, and the batteries included in the battery pack are connected in series; the balancing end of the charge transfer control circuit is used to be electrically connected to the battery pack; and the detection end of the balancing control circuit is used to be electrically connected to the battery pack. The balancing control circuit is configured to collect voltage change data of the batteries in the battery pack, and control the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack to perform a balancing charging control operation on the batteries in the battery pack; The balancing control circuit collects voltage change data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage change data of the batteries in the battery pack. The specific manner in which the balancing control circuit performs the balancing charge control operation on the batteries in the battery pack includes: When the voltage change data of the batteries in the battery pack indicates that there is a first battery in the battery pack whose current voltage change meets a predetermined first balanced charging condition, the balancing control circuit reduces the charging current of the battery pack according to the current voltage change of the first battery; the current voltage of the first battery is greater than the current voltage of each of all batteries in the battery pack except the first battery; after reducing the charging current of the battery pack, the balancing control circuit controls the charge transfer control circuit to connect with the first battery so that the charge of the first battery is transferred to the energy storage device of the charge transfer control circuit; when the charge transfer condition corresponding to the first battery meets a predetermined charge transfer termination condition, the balancing control circuit controls the first battery to disconnect from the charge transfer control circuit so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balancing control circuit controls the charge transfer control circuit to transfer the charge in the energy storage device of the charge transfer control circuit to the batteries in the battery pack except the first battery; The first battery that meets the first balanced charging condition includes a battery in the battery pack having a voltage difference between its current voltage and the current voltage of each remaining battery in the battery pack that is greater than or equal to a first balanced starting voltage, or a battery having a voltage rise rate that is greater than or equal to a first balanced voltage rise rate.

7. The control circuit for balanced charging based on charge transfer according to claim 6, characterized in that: The power control circuit includes a power pre-charge control module, a first switch module and a second switch module, wherein: The first end of the power pre-charge control module is electrically connected to the first end of the first switch module, the second end of the power pre-charge control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charge control module is electrically connected to the balancing control circuit; The second end of the first switch module is used to electrically connect to the battery pack, and the third end of the first switch module is used to electrically connect to the power supply module; The second end of the second switch module is electrically connected to the bus terminal of the charge transfer control circuit, and the third end of the second switch module is electrically connected to the controlled end of the charge transfer control circuit; Wherein, the bus terminal of the charge transfer control circuit and the controlled terminal of the charge transfer control circuit constitute the first controlled terminal of the charge transfer control circuit; The power pre-charge control module is configured to control the first switch module, the second switch module and the charge transfer control circuit under the control of the balancing control circuit to perform a balancing charging operation on the batteries in the battery pack.

8. The control circuit for balanced charging based on charge transfer according to claim 7, characterized in that: The charge transfer control circuit includes a charge transfer control module, a balanced charge and discharge bus and a plurality of switching switch groups; The balanced charge and discharge busbar includes a first busbar and a second busbar, the number of all the switch groups is equal to the number of all the batteries in the battery pack; each battery in the battery pack has a one-to-one corresponding switch group; The first controlled end of the charge transfer control module is electrically connected to the third end of the second switch module, the second controlled end of the charge transfer control module is electrically connected to the second control end of the balancing control circuit, the first transfer end of the charge transfer control module is electrically connected to one end of one of the switches in the switch group of each battery in the battery pack through the first bus, and the second transfer end of the charge transfer control module is electrically connected to one end of the other switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches in each switch group are electrically connected to the battery corresponding to the switch group; The charge transfer control module is configured to perform a balanced charging operation on the batteries in the battery pack through the balanced charge and discharge bus and the plurality of switching switch groups under the control of the balanced control circuit and the power control circuit.

9. The control circuit for balanced charging based on charge transfer according to claim 8, characterized in that: The charge transfer control circuit further includes a protection module; The protection module includes a saturable inductor and a linear inductor connected in series with the saturable inductor; the saturable inductor and the linear inductor are connected in series between the first transfer terminal of the charge transfer control module and the first bus; Wherein, the saturable inductor is used to suppress transient current spikes during the charging and discharging process of the charge transfer control circuit; The linear inductor is used to suppress the RMS value of the current during the charging process of the charge transfer control circuit; The charge transfer control circuit also includes a freewheeling absorption module; The freewheeling absorption module is connected in parallel to the saturable inductor and the linear inductor, and one end of the freewheeling absorption module is electrically connected to the second transfer end of the charge transfer control module; The freewheeling absorption module is used to absorb the energy stored in the saturable inductor and the linear inductor and release the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit.

10. A balanced charging control device, comprising a device body and the control circuit according to any one of claims 6 to 9, wherein the device body is used to house the control circuit, and the balanced charging control device is used to execute the control method for balanced charging based on charge transfer according to any one of claims 1 to 5.

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