Control method, circuit and equipment for equalizing charge based on charge transfer

Abstract

The invention relates to the technical field of battery equalization charging, and particularly discloses a control method, circuit and equipment for equalization charging based on charge transfer, and the equalization control circuit analyzes the collected voltage change data of a battery pack, and carries out active equalization control on a power control circuit and a charge transfer control circuit. Therefore, the power control circuit and the charge transfer control circuit perform active equalizing 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 in the use process. Therefore, the available capacity of the battery pack is improved, the service life of the battery pack is prolonged, the cask effect caused by series mismatch of the batteries is reduced, the thermal runaway caused by circulating current generated by parallel mismatch is reduced, the overall available capacity and the overall performance are further improved, and the service life is prolonged. And the use safety and reliability of the battery pack can be improved.

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] The current battery systems for household energy storage and industrial and commercial energy storage are composed of multiple PACKs connected in series and parallel in different ways to form the required voltage and capacity. Each PACK is composed of multiple batteries in series. According to different capacities and voltages, different numbers of PACKs will be connected in series to form a battery cluster, and then multiple battery clusters will form a container with a capacity of 100KW-several MW. From a small capacity of 5KWH to a large capacity of dozens of MWH, the number of battery cells is increasing, from dozens to hundreds, or even hundreds of thousands.

[0003] At present, the initial static balancing method is generally used for cell matching, that is, the ΔSOC capacity difference, ΔV voltage difference, and ΔR internal resistance difference between batteries are used for matching. However, in practice, it is found that this method cannot achieve accurate matching, and the life of each cell, self-discharge, internal gas production level (externally manifested as the pressure per unit area of ​​the module gradually increases), and the SOC internal resistance of the active material tend to be more and more inconsistent after N cycles in use. Moreover, the passive balancing current currently used in large quantities is only a few hundred milliamperes. For charging and discharging currents of several amperes, tens of amperes, or even thousands of amperes during use, it is impossible to keep each battery cell in a relatively consistent dynamic voltage and dynamic SOC during use, resulting in a decrease in the available capacity of the entire battery cabinet and the entire battery cluster and a shortened life.

[0004] Therefore, it is particularly important to propose a new method for actively balancing charging of a battery pack so that each battery cell 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 charge a battery pack so that each battery cell maintains a relatively consistent dynamic voltage and dynamic SOC during use, thereby increasing the available capacity of the battery and extending the service life of the battery.

[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, 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 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; the detection end of the balancing control circuit is used to be electrically connected to the battery pack; Wherein, the method comprises: The balancing control circuit collects voltage variation data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage variation data of the batteries in the battery pack, so as to perform a balancing charging control operation on the batteries in the battery pack.

[0007] As an optional implementation, 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: When the voltage change data of the batteries in the battery pack is used to indicate that there is a first battery in the battery pack whose current voltage change condition satisfies a predetermined first balanced charging condition, the balanced 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 battery in all batteries except the first battery in the battery pack; after reducing the charging current of the battery pack, the balanced control circuit controls 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; when the charge transfer condition corresponding to the first battery satisfies a predetermined charge transfer end condition, the balanced control circuit controls the first battery and the charge transfer control circuit to be disconnected so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balanced 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 except the first battery in the battery pack; When the voltage change data of the batteries in the battery pack is used to indicate that there is a second battery in the battery pack whose current voltage change condition satisfies a predetermined second balanced charging condition, the balanced control circuit selects the second battery from the batteries in the battery pack; the balanced control circuit controls the charge transfer control circuit so that the charge transfer control circuit is disconnected from the battery pack, the power control circuit is connected to the second battery, and the power control circuit is disconnected from all batteries in the battery pack except the second battery; the balanced control circuit controls the power control circuit to perform a balanced charging operation on the second battery through the total voltage of the battery pack until the voltage of the second battery after being charged reaches a first preset voltage, wherein the current voltage of the second battery is less than the current voltage of each battery in all batteries in the battery pack except the second battery.

[0008] As an optional implementation, 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: 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.

[0009] As an optional embodiment, in the first aspect of the present invention, 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 group to obtain the difference voltage corresponding to the first battery; The balancing control circuit determines the charge transfer termination condition according to the differential voltage corresponding to the first battery.

[0010] As an optional embodiment, in the first aspect of the present invention, 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 equalization control circuit triggers 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; 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 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 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 is performed; The method further comprises: The balancing control circuit acquires the current voltage of each battery in all batteries except the first battery in the battery pack; The balancing control circuit calculates an arithmetic mean value of current voltages of all batteries in the battery group except the first battery as the preset transfer voltage.

[0011] The 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: 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; the detection end of the balancing control circuit is used to be electrically connected to the battery pack; 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 a balancing charging control operation on the batteries in the battery pack.

[0012] 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: The first end of the power pre-charging control module is electrically connected to the first end of the first switch module, the second end of the power pre-charging control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charging 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 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.

[0013] As an optional implementation, 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; The balanced charge and discharge bus includes a first bus and a second bus, 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; Wherein, 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 another switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches of each switch group are electrically connected to the battery corresponding to the switch group; The charge transfer control module is used to perform a balanced charging operation on the batteries in the battery pack through the balanced charging and discharging bus and the multiple switching switch groups under the control of the balanced control circuit and the power control circuit.

[0014] As an optional implementation, in the second aspect of the present invention, the charge transfer control circuit further includes a protection module; Wherein, the protection module comprises 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; 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; 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.

[0015] A third aspect of the present invention discloses a balanced charging control device, the 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, and the device body is used to place 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.

[0016] The implementation of the present invention has the following beneficial effects: 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 comprises 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 electrically connect to a power supply module; the charging end of the power control circuit is used to electrically connect to a battery pack, the battery pack comprises at least two batteries, and each battery is connected in series; the balanced end of the charge transfer control circuit is used to electrically connect to the battery pack; the detection end of the balanced control circuit is used to electrically connect to the battery; wherein the balanced control circuit collects voltage change data of 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 of 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 reducing the occurrence of circulating current causing thermal runaway due to parallel mismatch, further improving the overall available capacity, overall performance and extending the service life, which is beneficial to improving the safety and reliability of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0018] Figure 1 It is a structural schematic diagram of a control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention; Figure 2 It 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 It is a structural schematic diagram of another control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention; Figure 4It is a structural schematic diagram of a balanced charging control device disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] 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 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 creative work are within the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise clearly 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, and it can be the internal connection of two elements or the interaction 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.

[0021] Also, reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] The present invention discloses a control method, circuit and device for balanced charging based on charge transfer. The balanced control circuit analyzes the collected voltage change data of the battery pack and actively balances the power control circuit and the 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 (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, reducing the occurrence of circulating current causing thermal runaway caused by 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. The following are detailed descriptions.

[0023] Embodiment 1 See also Figure 1-3 , Figure 1 is a schematic diagram of a control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention, Figure 2 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 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: 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; the charging end of the power control circuit is used to electrically connect to a battery pack, 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 electrically connect to the battery pack; and the detection end of the balancing control circuit is used to electrically connect to the battery pack.

[0024] like Figure 2 As shown, the control method for balanced charging based on charge transfer may include the following steps: 101. The balancing control circuit collects voltage change data of the batteries in the battery pack.

[0025] 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.

[0026] 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 each battery of 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 reducing the occurrence of circulating current causing thermal runaway due to parallel mismatch, further improving the overall available capacity, overall performance and extending the service life, which is beneficial to improving the safety and reliability of the battery pack.

[0027] 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 may 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 may 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 may be integrated into the direct charging power conversion module, or may 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 grounded through the sampling resistor Rs. Among them, the direct charging power conversion module is used to directly charge the battery of the battery pack. Furthermore, it is also used to charge the energy storage device of the charge transfer control circuit.

[0028] 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: A first end of the power pre-charging control module is electrically connected to a first end of the first switch module, a second end of the power pre-charging control module is electrically connected to a first end of the second switch module, and a controlled end of the power pre-charging control module is electrically connected to a balancing control circuit; 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; 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; 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.

[0029] 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 a plurality of 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, and the 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. For any switch group, its type may include but is not limited to one of MOS tubes (such as conduction loss Pd=I2×Rdson), relays, DC switches, and triodes, as long as it can realize the connection and disconnection of the 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 switching switches in the switching 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 switching switch in the switching switch group of each battery in the battery pack through the second bus; the other ends of the two switching switches of each switching switch group are electrically connected to the battery corresponding to the switching switch group.

[0030] In the embodiment of the present invention, optionally, 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 is used to indicate that there is a first battery in the battery pack whose current voltage change condition satisfies a predetermined first balanced charging condition, the balanced 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 battery in all batteries except the first battery in the battery pack; after reducing the charging current of the battery pack, the balanced 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 end condition, the balanced control circuit controls the first battery and the charge transfer control circuit to disconnect so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balanced 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 except the first battery in the battery pack; When the voltage change data of the batteries in the battery pack is used to indicate that there is a second battery in the battery pack whose current voltage change condition satisfies a predetermined second balanced charging condition, the balanced control circuit selects the second battery from the batteries in the battery pack; the balanced 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 balanced control circuit controls the power control circuit to perform a balanced charging operation on the second battery through 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 battery in all batteries in the battery pack except the second battery.

[0031] In the embodiment of the present invention, optionally, the balancing control circuit detects voltage change data of batteries in the battery pack. When the voltage change data of batteries in the battery pack is used to indicate that there is a first battery in the battery pack whose difference voltage between a current voltage and a 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 satisfies a predetermined first balancing charging condition.

[0032] 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 cannot achieve the expected voltage reduction effect, and other batteries in the battery pack cannot achieve the expected voltage boost effect.

[0033] In the embodiment of the present invention, optionally, the balancing control circuit detects voltage change data of batteries in the battery pack. When the voltage change data of batteries in the battery pack is used to indicate that there is a second battery in the battery pack whose difference voltage between a current voltage and a 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 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 condition satisfies a predetermined second balancing charging condition.

[0034] In the embodiment of the present invention, specifically, the balancing control circuit controls the switching switch groups SW11 and SW12 corresponding to the first battery (taking BAT1 as an example) to close, so that the charge transfer control module is 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 module. When the charge transfer situation corresponding to the first battery meets the charge transfer end condition, the balancing control circuit controls the switching switch groups SW11 and SW12 to disconnect, so that the first battery and the charge transfer control module are disconnected, so that the first battery stops transferring charge to the energy storage device of the charge transfer control module. Optionally, the energy storage device can be a supercapacitor, or a common capacitor (such as an electrolytic capacitor, a ceramic capacitor, a CBB capacitor, etc.), or a battery (such as a solid-state battery, a solid-liquid hybrid battery, a liquid battery of various materials at present, etc.), or an electric energy storage device of a certain material or method in the future, as long as it can act as an energy repeater.

[0035] 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 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 voltages of all the third batteries reach the corresponding second preset voltage.

[0036] 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.

[0037] In the embodiment of the present invention, specifically, Figure 3 Taking the low voltage battery BAT2, BAT3, BAT4 as an example, the control unit MCU simultaneously controls the switching switch groups SW21 and SW22, SW31 and SW32, SW41 and SW42 corresponding to each third battery in all the third batteries BAT2, BAT3, BAT4, so that the charge transfer control module is connected to each third battery at the same time, so that the charge in the energy storage device of the charge transfer control module is transferred to all the third batteries at the same time, so that each third battery can obtain the corresponding amount of electricity, that is, reach the corresponding second preset voltage. Alternatively, the control unit MCU first controls the switching 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, so that the charge in the energy storage device of the charge transfer control module is transferred to the third battery BAT2, and after the third battery BAT2 reaches the corresponding second preset voltage, the switching switch groups SW21 and SW22 are controlled to be disconnected, so that the charge transfer control module is first disconnected from the third battery BAT2, and the charge transfer is performed on the third batteries BAT3 and BAT4 in the same way to obtain the corresponding second preset voltage.

[0038] 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 repeated to achieve active balancing charging.

[0039] 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.

[0040] In an optional embodiment, the method may further include the following steps: The balancing control circuit calculates the 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 group to obtain the difference voltage corresponding to the first battery; The balancing control circuit determines a charge transfer termination condition according to the differential voltage corresponding to the first battery.

[0041] In this optional embodiment, specifically, Figure 3 The battery pack shown contains 4 batteries BAT1, BAT2, BAT3, and BAT4. The current voltages of BAT1, BAT2, BAT3, and BAT4 are respectively Ua, Ub, Uc, and Ud. In theory, the voltage of each battery after active equalization charging should be equal, specifically Ux=(Ua+Ub+Uc+Ud) / 4. Corresponding to the BAT1 battery, the voltage to be discharged is ΔVa=Ua-Ux, where the ΔVa of the battery BAT1 can be directly used as the charge transfer termination condition, that is, if the voltage corresponding to the charge discharged by the battery BAT1 reaches ΔVa, it means that the charge transfer termination condition is met. Alternatively, the ΔVa of the battery BAT1 can be multiplied by a voltage coefficient, such as 1.2, that is, if the voltage corresponding to the charge discharged by the battery BAT1 reaches 1.2*ΔVa, it means that the charge transfer termination condition is met.

[0042] In this optional embodiment, for BAT2, BAT3, and BAT4 batteries, the voltages that need to be charged 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 current I, and the duration T, it can be obtained that the capacity of the energy storage device required for charging the battery BAT2 is Cb=IT / ΔVb, the capacity of the energy storage device required for charging the battery BAT3 is Cc=IT / ΔVc, and the capacity of the energy storage device required for charging the battery BAT4 is Cd=IT / ΔVd. The total capacity is Cx=Cb+Cc+Cd. The best case is that the capacities of the energy storage devices required for the three batteries are the same, that is, Cx=3Cc. However, considering the main switch of the charge-discharge balancing bus (i.e., the switching switch group corresponding to the battery), especially the MOS tube, which has conduction loss and resistive loss of the charge-discharge balancing bus and energy storage devices, especially capacitor types, the loss of equivalent series resistance, 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.

[0043] It can be seen that this optional embodiment can improve the accuracy and efficiency of the charge transfer termination condition 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 condition of the high-voltage battery, which is beneficial to improve the accuracy and efficiency of the charge required to be transferred from the high-voltage battery, and further helps to improve the probability of each battery in the battery pack maintaining a relatively consistent dynamic voltage and dynamic SOC during use (including charging).

[0044] In another optional embodiment, the method may further include the following steps: The balancing control circuit obtains the attribute parameters of the target components, wherein the target components include one or more of a charge-discharge balancing bus, a switching switch group, and an energy storage device; wherein the attribute parameters of the charge-discharge balancing bus 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 the circuit structure composition (such as a capacitor and a resistor connected in parallel with it, an inductor and a resistor connected in series with it), wherein the description of the type of the switching switch group and the type of the energy storage device is detailed in the relevant description elsewhere in the present invention; The balancing control circuit obtains the usage time of each target component, and estimates the charge loss caused by the charge transfer for any target component according to the usage time and the corresponding property parameters of the target component, wherein different property parameters have different degrees of charge loss caused by the charge transfer, such as the charge loss caused by the supercapacitor to the charge transfer is smaller than that of the ordinary capacitor; and the longer the usage time, the greater the charge loss caused by the charge transfer; The balancing control circuit determines the preset capacity factor according to the charge loss corresponding to all target components, wherein the greater the charge loss, the greater the corresponding preset capacity factor, indicating that more charge needs to be transferred from the energy storage device. Furthermore, at this time, the preset transfer voltage will also increase relatively to meet the increase in charge loss.

[0045] It can be seen that this optional embodiment analyzes the charge loss generated in the charge transfer process by analyzing 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, which is beneficial to further improve the accuracy of the energy storage device transferring the charge to the low-voltage battery, and further helps to further improve the consistency of the dynamic charge between the batteries in the battery pack.

[0046] In yet another optional embodiment, the method may further include the following steps: 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; When it is determined that the voltage is greater than or equal to the preset transfer voltage, the balancing control circuit triggers the above-mentioned control of connecting the charge transfer control circuit 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; 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 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 with 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.

[0047] 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 first switch module; after both are in contact, the balancing control circuit controls the power pre-charge control module to charge the energy storage device of the charge transfer control circuit with the voltage of the power supply module 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, in the process of charging 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 of the switching switch group corresponding to the battery pack during the charging time, and protecting the switching switch group from damage.

[0048] It can be seen that, before transferring the charge of the high-voltage battery to the energy storage device of the charge transfer control circuit, the optional embodiment first analyzes the current voltage (charge) in the energy storage device. If it is greater than or equal to the preset transfer voltage, the subsequent charge transfer operation continues. If not, it is charged based on the power control circuit and the charge transfer control circuit, and when the current voltage is greater than or equal to the preset transfer voltage, the high-voltage battery is connected for charge transfer. This can ensure that the charge transfer is performed when the voltage difference between the energy storage device and the high-voltage battery is relatively small, reduce the current, improve the safety of the high-voltage battery for charge transfer, and reduce the damage to components, especially capacitor-type energy storage devices, whose inherent physical property is that the voltage at both 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; and the saturable inductor and linear inductor in the charge transfer control module are used to suppress the current, further reducing the current of the circuit and further improving the safety of charge transfer.

[0049] In yet another optional embodiment, the method may further include the following steps: The balancing control circuit obtains the current voltage of each battery in all batteries except the first battery in the battery pack; The balancing control circuit calculates an arithmetic mean value of the current voltages of all batteries except the first battery in the battery pack as a preset transfer voltage.

[0050] In this optional embodiment, the preset transfer voltage can be the arithmetic mean voltage 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 the arithmetic mean voltage. Further, in the process of charging the energy storage device, the arithmetic mean voltage of all low-voltage batteries in the battery pack is constantly monitored and tracked, and the voltage arithmetic mean voltage can be kept consistent at all times, so that when the equalization circuit with a large voltage difference is started, the charging current of the high-voltage battery to the energy storage device will be much smaller, and combined with the linear inductor and saturable inductor connected in series in the charge transfer control module, the change rate of the supercapacitor charging and discharging current rise period is reduced.

[0051] 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, which is beneficial to further improve the accuracy and safety of transferring the charge in the high-voltage battery to the energy storage device.

[0052] In yet 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; 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.

[0053] It can be seen that this optional embodiment can suppress transient current spikes during the charging and discharging process of the charge transfer control circuit and suppress the root mean square value of 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 of the charge transfer control module to 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.

[0054] In yet another optional embodiment, Figure 3As shown, the charge transfer control circuit may also 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 and release the energy to the battery of the battery pack or the energy storage device of the charge transfer control circuit. wherein the freewheeling absorption module may be composed of one or more of a freewheeling diode, an RC absorption circuit, a transient voltage suppression diode, and a varistor, as long as it can 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.

[0055] It can be seen that this optional embodiment, by setting a freewheeling absorption module between the charge transfer control module and the bus and connecting it in parallel with the protection module, absorbs the energy stored in the saturable inductor and the linear inductor 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 damaging 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 under the charging state of the battery pack.

[0056] In yet 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. Further, 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 charging or discharging. Optionally, the temperature detection module specifically corresponds to Figure 3The temperature sensor in the battery pack is fed back to the control unit MCU, and the MCU 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 balanced charging operations on the batteries in the battery pack. If the temperature of the detected battery is greater than or equal to the preset temperature, the active balanced charging operation is stopped. When the temperature of the detected battery is less than the preset temperature, the active balanced charging operation is continued. In this way, by setting corresponding temperature sensors for the batteries in the battery pack, the temperature of the battery pack batteries during the charging and discharging process is detected, and the charging or active balanced charging operation of the battery pack is stopped or continued according to the temperature detection result. While realizing the charging and discharging of the battery pack and the active balanced charging during the charging and discharging process, the damage of components caused by excessive temperature is reduced, and the electronic components in the circuit are protected.

[0057] It should be noted that the discharge process and the charging process of the battery in the battery pack are mutually convertible processes. The batteries contained in the battery pack are connected in series, which can be understood as all the batteries contained in the battery pack are connected in series, or it can be understood as multiple sub-battery groups are connected in series, wherein the batteries of each sub-battery group are connected in parallel. If the capacity of a single battery is large or the number of batteries in a single sub-battery group is large, then the capacity of the energy storage device required is larger. Figure 3 The technical solution is explained by taking a battery pack composed of 4 batteries as an example, that is, the 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, wherein for each additional battery, a switching switch group and a corresponding temperature detection module are added.

[0058] Embodiment 2 A control circuit for balanced charging based on charge transfer disclosed in an embodiment of the present invention is as follows: Figure 1 As shown, 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 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, the battery pack 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; the detection end of the balancing control circuit is used to electrically connect to the battery.

[0059] 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.

[0060] 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: A first end of the power pre-charging control module is electrically connected to a first end of the first switch module, a second end of the power pre-charging control module is electrically connected to a first end of the second switch module, and a controlled end of the power pre-charging control module is electrically connected to a balancing control circuit; 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; 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; 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; 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.

[0061] 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 a plurality of 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.

[0062] Wherein, 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 another switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches of each switch group are electrically connected to the battery corresponding to the switch group; Among them, the charge transfer control module is used to perform balanced charging operations on the batteries in the battery pack through a balanced charging and discharging bus and multiple switching switch groups under the control of the balanced control circuit and the power control circuit.

[0063] In an optional embodiment, if Figure 3 As shown, the charge transfer control circuit may further include a protection module; Wherein, 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; 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.

[0064] It can be seen that this optional embodiment can suppress transient current spikes during the charging and discharging process of the charge transfer control circuit and suppress the root mean square value of 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 of the charge transfer control module to 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.

[0065] In another optional embodiment, 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; 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.

[0066] It can be seen that this optional embodiment, by setting a freewheeling absorption module between the charge transfer control module and the bus and connecting it in parallel with the protection module, absorbs the energy stored in the saturable inductor and the linear inductor 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 damaging 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 under the charging state of the battery pack.

[0067] In the embodiment of the present invention, Figure 3 As shown, the balancing control circuit may be a control unit MCU, and may 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 may be as follows: Figure 3 As shown, further, the charging current detection of the battery pack can be realized 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, and the MCU 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 balanced charging operations on the batteries in the battery pack. If the temperature of the detected battery is greater than or equal to the preset temperature, the active balanced charging operation is stopped. When the temperature of the detected battery is less than the preset temperature, the active balanced charging operation is continued. In this way, by setting corresponding temperature sensors for the batteries in the battery pack, the temperature of the battery pack batteries during the charging and discharging process is detected, and the active balanced charging operation is stopped or continued according to the temperature detection result, while realizing the charging and discharging of the battery pack and the active balanced charging during the charging and discharging process, the damage of components caused by excessive temperature is reduced, and the electronic components in the circuit are protected.

[0068] Embodiment 3 See also Figure 4 As shown, Figure 4 1 is a schematic diagram of a balanced charging control device disclosed in an embodiment of the present invention, wherein the balanced charging control device can actively balance charge a 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 described circuit, 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 the first embodiment.

[0069] 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 Embodiments 1 and 2, which will not be repeated in this embodiment.

[0070] It can be seen that implementation Figure 4 The described balanced charging control device can analyze the collected voltage change data of the battery pack based on the balanced control circuit set by the balanced control circuit, and actively balance the power control circuit and the 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 of 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 reducing the occurrence of circulating current causing thermal runaway 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.

[0071] The above is a detailed introduction to a control method, circuit and device for balanced charging based on charge transfer disclosed in an embodiment of the present invention. The principles and implementation methods of the present invention are described in detail using specific embodiments. However, the above preferred embodiments are not intended to limit the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be based on the scope defined in 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; the detection end of the balancing control circuit is used to be electrically connected to the battery pack; Wherein, the method comprises: The balancing control circuit collects voltage variation data of the batteries in the battery pack, and controls the power control circuit and the charge transfer control circuit according to the voltage variation data of the batteries in the battery pack, so as to perform a balancing charging control operation on the batteries in the battery pack.

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, and performs 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 is used to indicate that there is a first battery in the battery pack whose current voltage change condition satisfies a predetermined first balanced charging condition, the balanced 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 battery in all batteries except the first battery in the battery pack; after reducing the charging current of the battery pack, the balanced control circuit controls 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; when the charge transfer condition corresponding to the first battery satisfies a predetermined charge transfer end condition, the balanced control circuit controls the first battery and the charge transfer control circuit to be disconnected so that the first battery stops transferring charge to the energy storage device of the charge transfer control circuit; the balanced 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 except the first battery in the battery pack; When the voltage change data of the batteries in the battery pack is used to indicate that there is a second battery in the battery pack whose current voltage change condition satisfies a predetermined second balanced charging condition, the balanced control circuit selects the second battery from the batteries in the battery pack; the balanced control circuit controls the charge transfer control circuit so that the charge transfer control circuit is disconnected from the battery pack, the power control circuit is connected to the second battery, and the power control circuit is disconnected from all batteries in the battery pack except the second battery; the balanced control circuit controls the power control circuit to perform a balanced charging operation on the second battery through the total voltage of the battery pack until the voltage of the second battery after being charged reaches a first preset voltage; wherein the current voltage of the second battery is less than the current voltage of each battery in 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 group to obtain the difference voltage corresponding to the first battery; The balancing control circuit determines the charge transfer termination 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 equalization control circuit triggers 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; 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 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 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 is performed; The method further comprises: The balancing control circuit acquires the current voltage of each battery in all batteries except the first battery in the battery pack; The balancing control circuit calculates an arithmetic mean value of current voltages of all batteries in the battery group 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; the detection end of the balancing control circuit is used to be electrically connected to the battery pack; 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 a balancing charging control operation on the batteries in the battery pack.

7. The control circuit for balanced charging based on charge transfer according to claim 6, characterized in that: The power control circuit comprises a power pre-charge control module, a first switch module and a second switch module, wherein: The first end of the power pre-charging control module is electrically connected to the first end of the first switch module, the second end of the power pre-charging control module is electrically connected to the first end of the second switch module, and the controlled end of the power pre-charging 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 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.

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 switch groups; The balanced charge and discharge bus includes a first bus and a second bus, 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; Wherein, 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 another switch in the switch group of each battery in the battery pack through the second bus; the other ends of the two switches of each switch group are electrically connected to the battery corresponding to the switch group; The charge transfer control module is used to perform a balanced charging operation on the batteries in the battery pack through the balanced charging and discharging bus and the multiple 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 also includes a protection module; Wherein, the protection module comprises 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; 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; 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 a control circuit as claimed in any one of claims 6 to 9, wherein the device body is used to place the control circuit, and the balanced charging control device is used to execute the control method for balanced charging based on charge transfer as claimed in any one of claims 1 to 5.

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