Energy storage battery equalization circuit, method and energy storage battery equalizer

Abstract

The present application relates to an energy storage battery balancing circuit and an energy storage battery equalizer. The energy storage battery balancing circuit includes a plurality of first battery modules connected in series, a plurality of second battery modules connected in series, a first balancing module and a plurality of second balancing modules. When the voltage difference between any two battery modules meets a preset condition, the first balancing module switches the flow direction of the charge and discharge current between each first battery module, and each second balancing module switches the flow direction of the charge and discharge current between each first battery module and the corresponding second battery module, so that the voltage difference between any two battery modules is within a preset range, thereby achieving energy balancing in two different directions at the same time, reducing energy loss, shortening the energy transmission path, and improving the utilization rate and service life of battery energy.

Description

Technical Field

[0001] The present application relates to the field of energy storage battery balancing control, and in particular to an energy storage battery balancing circuit, method and energy storage battery equalizer. Background Art

[0002] In recent years, the implementation of the "dual carbon" policy has enabled my country's energy storage industry to make great progress, especially the application of lithium batteries. When energy storage batteries are in use, a single battery cell usually cannot meet the needs of actual applications. Therefore, in order to obtain higher voltage and power, multiple battery cells are generally used in series or in parallel. However, due to the characteristics of deep charging and discharging of energy storage systems, after multiple charges and discharges, the consistency of the battery cell capacity within the battery cluster will have a serious impact on the available capacity of the energy storage system. If effective measures are not taken, the reliability of the entire energy storage battery system will be greatly reduced, its service life will be shortened, and even serious safety hazards may be caused. Therefore, the development of a safe, efficient and reliable battery balancing control system is of great significance to improving the inconsistency between battery cells.

[0003] The existing battery balancing technology requires a large number of balancing times, a long balancing time, and a high cost to achieve cyclic balancing of the entire system, and is not suitable for occasions requiring a large number of batteries. Summary of the invention

[0004] Based on this, it is necessary to provide an energy storage battery balancing circuit, method and energy storage battery equalizer, which can simultaneously achieve balancing in two different directions, reduce the loss of energy transfer between batteries, shorten the energy transfer path, and improve the utilization rate and balancing speed of battery energy.

[0005] An energy storage battery balancing circuit, comprising:

[0006] A plurality of first battery modules connected in series and a plurality of second battery modules connected in series;

[0007] A first balancing module is connected to the positive terminal and the negative terminal of each of the first battery modules respectively;

[0008] A plurality of second balancing modules, wherein the two first ends of each of the second balancing modules are respectively connected to the positive terminal and the negative terminal of one of the first battery modules, and the two second ends of each of the second balancing modules are respectively connected to the positive terminal and the negative terminal of one of the second battery modules;

[0009] Wherein, each of the first battery modules and a corresponding second battery module share a second balancing module; when the voltage difference between any two battery modules meets a preset condition, the first balancing module is used to switch the flow direction of the charge and discharge current between each of the first battery modules, so that the voltage difference between the first battery modules is within a preset range; each of the second balancing modules is used to switch the flow direction of the charge and discharge current between each of the first battery modules and the corresponding second battery module, so that the voltage difference between any of the first battery modules and the corresponding second battery module is within a preset range. In one embodiment, the first balancing module includes:

[0010] A plurality of first balancing units, wherein the first ends of each of the first balancing units are connected to each other, and the second ends of each of the first balancing units are respectively connected to the positive terminal and the negative terminal of a first battery module, and are used to switch the flow direction of the charge and discharge current between the first battery modules when the voltage difference between any two of the first battery modules meets a preset condition, so that the voltage difference between any two of the first battery modules is within a preset range.

[0011] In one embodiment, the first equalization unit comprises:

[0012] an energy storage inductor, wherein a first end of the energy storage inductor is respectively connected to a negative terminal of a corresponding one of the first battery modules and a positive terminal of another first battery module connected in series to the corresponding one of the first battery modules, and a voltage value of another first battery module is lower than that of the corresponding one of the first battery modules;

[0013] A first switch tube, wherein the first switch tubes of each of the first balancing units are connected in series, and a first end of each of the first switch tubes is further connected to a second end of the corresponding energy storage inductor;

[0014] The second end of the first switch tube of the first first balancing unit is connected to the positive terminal of a corresponding first battery module, and the second end of the first switch tube of the last first balancing unit is connected to the negative terminal of a corresponding first battery module.

[0015] In one embodiment, the second equalization module includes:

[0016] an energy storage unit, wherein a first end of the energy storage unit is connected to a positive end of the first battery module, a second end of the energy storage unit is connected to a negative end of the first battery module, a third end of the energy storage unit is connected to a negative end of the second battery module, and a fourth end of the energy storage unit is connected to a positive end of the second battery module, and is used to receive electric energy transmitted by a battery module at a high voltage when a voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, and release and transmit the electric energy to a battery module at a low voltage, so that the voltage difference between any two of the first battery modules and the second battery modules is within a preset range;

[0017] A switch unit, wherein the first end of the switch unit is connected to the second end of the energy storage unit, and the second end of the switch unit is connected to the fourth end of the energy storage unit, and is used to close or open when the voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, so as to switch the direction of the charge and discharge current between each of the first battery modules and each of the second battery modules.

[0018] In one embodiment, the energy storage unit comprises:

[0019] A coupled inductor, wherein a first end of the coupled inductor is connected to a positive terminal corresponding to the first battery module, and a second end of the coupled inductor is connected to a negative terminal corresponding to the second battery module;

[0020] An energy storage capacitor, wherein two ends of the energy storage capacitor are respectively connected to two ends of the coupling inductor.

[0021] In one embodiment, the coupled inductor comprises:

[0022] A first coupled inductor, wherein a like-name end of the first coupled inductor is connected to a positive terminal of a corresponding first battery module, and an opposite-name end of the first coupled inductor is respectively connected to a first end of the energy storage capacitor and a first end of the switch unit;

[0023] A second coupled inductor, wherein the same-name end of the second coupled inductor is connected to the negative terminal of the corresponding second battery module, and the opposite-name end of the second coupled inductor is respectively connected to the second end of the energy storage capacitor and the second end of the switch unit.

[0024] In one embodiment, the energy storage capacitor comprises:

[0025] A first capacitor, wherein two ends of the first capacitor are respectively connected to opposite-name ends of the first coupled inductor and opposite-name ends of the second coupled inductor;

[0026] A second capacitor, wherein a first end of the second capacitor is connected to a negative end of a corresponding first battery module, and a second end of the second capacitor is connected to a positive end of a corresponding second battery module.

[0027] In one embodiment, the switch unit comprises:

[0028] a second switch tube, wherein a first end of the second switch tube is respectively connected to the opposite-name end of the first coupled inductor and the first end of the first capacitor, and a second end of the second switch tube is connected to the first end of the second capacitor;

[0029] a third switch tube, wherein a first end of the third switch tube is respectively connected to the opposite-name end of the second coupled inductor and the second end of the first capacitor, and a second end of the third switch tube is connected to the second end of the second capacitor;

[0030] Wherein, the second end of the second switch tube of the last second balancing module is directly connected to the second end of the third switch tube.

[0031] In one embodiment, it also includes:

[0032] The control module is respectively connected to the gate of each switch tube, and is used to control the closing and opening of each switch tube when the voltage difference between any two of the battery modules meets a preset condition, so as to switch the flow direction of the charge and discharge current between any two of the battery modules.

[0033] The present application also proposes an energy storage battery equalizer, comprising the energy storage battery equalization circuit as described above.

[0034] The present application also proposes a method for balancing an energy storage battery, comprising:

[0035] When the voltage difference between any two battery modules meets a preset condition, controlling the first balancing module to switch the flow direction of the charge and discharge current between the first battery modules so that the voltage difference between the first battery modules is within a preset range;

[0036] and controlling the second balancing module to switch the direction of the charge and discharge current between each of the first battery modules and the corresponding second battery module, so that the voltage difference between any of the first battery modules and the corresponding second battery module is within a preset range.

[0037] The energy storage battery balancing circuit, method and energy storage battery equalizer described above, the energy storage battery balancing circuit comprises a plurality of first battery modules connected in series, a plurality of second battery modules connected in series, a first balancing module and a plurality of second balancing modules. When the voltage difference between any two battery modules meets a preset condition, the first balancing module switches the flow direction of the charge and discharge current between each first battery module, and each second balancing module switches the flow direction of the charge and discharge current between each first battery module and the corresponding second battery module, so that the voltage difference between any two battery modules is within a preset range, thereby achieving energy balancing in two different directions at the same time, reducing energy loss, shortening the energy transfer path, and improving the utilization rate and service life of the battery energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is one of the structural block diagrams of an energy storage battery equalization circuit according to an embodiment;

[0040] Figure 2 This is a second structural block diagram of an energy storage battery balancing circuit according to an embodiment;

[0041] Figure 3 A circuit diagram of an energy storage battery balancing circuit according to an embodiment;

[0042] Figure 4 The balancing mode 1 of the first balancing module of the energy storage battery balancing circuit of one embodiment;

[0043] Figure 5 The balancing mode 2 of the first balancing module of the energy storage battery balancing circuit of one embodiment;

[0044] Figure 6 The balancing mode 3 of the first balancing module of the energy storage battery balancing circuit of one embodiment;

[0045] Figure 7 The balancing mode n of the first balancing module of the energy storage battery balancing circuit of an embodiment;

[0046] Figure 8 A waveform diagram of a first equalization module of an energy storage battery equalization circuit according to an embodiment;

[0047] Fig. 9 The balancing mode 1 of the second balancing module of the energy storage battery balancing circuit of one embodiment;

[0048] Fig.10 The balancing mode 2 of the second balancing module of the energy storage battery balancing circuit of one embodiment;

[0049] Fig.11 One of the balancing modes n of the second balancing module of the energy storage battery balancing circuit of an embodiment;

[0050] Fig.12 The second balancing mode n of the second balancing module of the energy storage battery balancing circuit of an embodiment;

[0051] Fig.13 A waveform diagram of a second equalization module of an energy storage battery equalization circuit according to an embodiment;

[0052] Fig.14 The figure is a flow chart of a method for balancing energy storage batteries according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0055] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first switch tube may be referred to as a second switch tube, and similarly, a second switch tube may be referred to as a first switch tube. Both the first switch tube and the second switch tube are switch tubes, but they are not the same switch tube.

[0056] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0057] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0058] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0059] Figure 1 This is one of the structural block diagrams of the energy storage battery equalization circuit of an embodiment, referring to Figure 1 As shown, the energy storage battery balancing circuit of this embodiment includes: a plurality of first battery modules 100 , a plurality of second battery modules 200 , a first balancing module 300 and a plurality of second balancing modules 400 .

[0060] A plurality of first battery modules 100 and a plurality of second battery modules 200 are connected in series respectively; a first balancing module 300 is connected to the positive terminal and the negative terminal of each first battery module 100 respectively; a plurality of second balancing modules 400, wherein the two first terminals of each second balancing module 400 are connected to the positive terminal and the negative terminal of a first battery module 100 respectively, and the two second terminals of each second balancing module 400 are connected to the positive terminal and the negative terminal of a second battery module 200 respectively; wherein each first battery module 100 and a corresponding second battery module 200 share a second balancing module 400; when the voltage difference between any two battery modules meets a preset condition, the first balancing module 300 is used to switch the flow direction of the charge and discharge current between each first battery module 100, so that the voltage difference between the first battery modules 100 is within a preset range; each second balancing module 400 is used to switch the flow direction of the charge and discharge current between each first battery module 100 and the corresponding second battery module 200, so that the voltage difference between any first battery module 100 and the corresponding second battery module 200 is within a preset range.

[0061] Among them, the first ends of multiple first battery modules 100 are connected in series with each other, and the first balancing module 300 is respectively connected to the positive terminal and the negative terminal of each first battery module 100, forming a longitudinal balancing module along the series direction of the first battery modules 100, which can achieve energy balance between any two first battery modules 100; the first end of each second balancing module 400 is respectively connected to the positive terminal and the negative terminal of the first battery module 100, and the second end of each second balancing module 400 is respectively connected to the positive terminal and the negative terminal of the second battery module 200, forming a transverse balancing module from the first battery module 100 to the second battery module 200, which can achieve energy balance between any two first battery modules 100 and the corresponding second battery module 200.

[0062] Optionally, the preset condition may be that the voltage difference between a battery at high energy and a battery at low energy is greater than a preset threshold, for example, greater than 50 mV. Generally, as the charge and discharge cycles increase, the voltages of each single cell gradually diverge. If the voltage deviation of a lithium battery cell during charging is above 50 mV, the battery life will be severely shortened.

[0063] Optionally, the preset range may be such that after balancing control, the voltage difference between any two battery modules is within 0-50 mV, which does not affect the use of the battery.

[0064] Optionally, a DC / DC conversion method can be used to achieve balance between battery modules. The DC / DC converter mainly converts the voltage value of the input power supply through the energy storage characteristics of switches, inductors and capacitors. The first balancing module 300 can be, for example, a switching inductor circuit, and the second balancing module 200 can be, for example, a Cuk circuit, a bidirectional flyback converter, etc., which can achieve balance between battery cells and transfer power between PACKs. Compared with traditional Buck-Boost or Cuk balancing circuits between adjacent batteries, the overall balancing efficiency is greatly improved.

[0065] Therefore, the energy storage battery balancing circuit provided in this embodiment switches the flow direction of the charge and discharge current between the first battery modules 100 through the first balancing module 300 when the voltage difference between any two battery modules meets the preset condition, so that the voltage difference between the first battery modules 100 is within a preset range, and switches the flow direction of the charge and discharge current between each first battery module 100 and the corresponding second battery module 200 through each second balancing module 400, so that the voltage difference between any first battery module 100 and the corresponding second battery module 200 is within a preset range, so as to achieve energy balancing in two different directions at the same time, thereby reducing energy loss, shortening the energy transmission path, and improving the utilization rate and service life of the battery energy.

[0066] Figure 2 This is a second structural block diagram of an energy storage battery balancing circuit according to an embodiment of the present invention. Figure 2 In this embodiment, the first balancing module 300 includes: a plurality of first balancing units 310 .

[0067] A plurality of first balancing units 310, wherein the first ends of each first balancing unit 310 are connected to each other, and the second ends of each first balancing unit 310 are respectively connected to the positive terminal and the negative terminal of a first battery module 100, and are used to switch the flow direction of the charge and discharge current between the first battery modules 100 when the voltage difference between any two first battery modules 100 meets a preset condition, so that the voltage difference between any two first battery modules 100 is within a preset range.

[0068] Therefore, the plurality of first balancing units 310 form a longitudinal balancing module along the series connection direction of the plurality of first battery modules 100 , and can achieve energy balancing between any two first battery modules 100 .

[0069] Optionally, when voltage inconsistency occurs between any two first battery modules 100, that is, when the voltage difference between any two first battery modules 100 meets a preset condition, part of the energy of the high-voltage battery is transferred to the low-voltage battery by switching the direction of the charge and discharge current between the first battery modules 100, so that the voltage difference between any two first battery modules 100 is within a preset range.

[0070] In one embodiment, if Figure 3 As shown, the first balancing unit 310 includes: an energy storage inductor Li and a first switch tube Si (the energy storage inductor Li and the first switch tube Si represent any inductor and switch tube respectively, as shown in the figure, i can be 1, 2, 3..., n respectively).

[0071] The first end of the energy storage inductor Li is respectively connected to the negative end of a corresponding first battery module 100 and the positive end of another first battery module 100 connected in series with the corresponding first battery module 100, and the voltage value of the other first battery module is lower than that of the corresponding first battery module; the first switch tube Si, the first switch tube Si of each first balancing unit 310 is connected in series with each other, and the first end of each first switch tube Si is also connected to the second end of the corresponding energy storage inductor Li.

[0072] The second end of the first switch tube Si of the first first balancing unit 310 is connected to the positive terminal of the corresponding first battery module 100 , and the second end of the first switch tube Si of the last first balancing unit 310 is connected to the negative terminal of the corresponding first battery module 100 .

[0073] When the voltage difference between any two first battery modules 100 meets the preset conditions, the first switch tube Si corresponding to the high-energy battery module is closed, and the first switch tubes Si corresponding to the remaining battery modules are turned off. Optionally, the first switch tube can be a MOS tube. According to the freewheeling characteristics of the body diode in the closed first switch tube Si, the flow direction of the charging and discharging current between the first battery modules 100 is switched, and the battery energy is transferred one by one through the energy storage inductor Li until the voltage difference between any two first battery modules 100 is within the preset range, thereby completing the energy balance between the first battery modules 100 within one cycle, thereby reducing the complexity of the control strategy.

[0074] In addition, compared with the existing balancing topology structure, the first balancing module 300 reduces the number of switches and inductors used, thereby reducing the cost of the equalizer while ensuring that the balancing speed is not reduced.

[0075] Optionally, please continue to refer to Figure 3 The second balancing module 400 includes: an energy storage unit 410 and a switch unit 420 .

[0076] An energy storage unit 410, wherein a first end of the energy storage unit 410 is connected to a positive end of a first battery module 100, a second end of the energy storage unit 410 is connected to a negative end of a first battery module 100, a third end of the energy storage unit 410 is connected to a negative end of a second battery module 200, and a fourth end of the energy storage unit 410 is connected to a positive end of a second battery module 200, and is used to receive electric energy transmitted from a battery module at high voltage when a voltage difference between any two first battery modules 100 and second battery modules 200 meets a preset condition, and to release and transmit electric energy to a battery module at low voltage, so that the voltage difference between any two first battery modules 100 and second battery modules 200 is within a preset range.

[0077] The switch unit 420 has a first end connected to the second end of the energy storage unit 410, and a second end connected to the fourth end of the energy storage unit 410, and is used to close or open when the voltage difference between any two first battery modules 100 and the second battery modules 200 meets a preset condition, so as to switch the direction of the charge and discharge current between each first battery module 100 and each second battery module 200.

[0078] When the voltage difference between the two first battery modules 100 and the second battery module 200 connected to any one of the second balancing modules 400 satisfies a preset condition, the first switch unit 420 is closed to switch the direction of the charge and discharge current between the first battery module 100 and the second battery module 200, so that part of the energy of the high-energy battery module is transferred to the low-energy battery module through the energy storage unit 410, until the voltage difference between the two first battery modules 100 and the second battery module 200 is within a preset range, the energy balancing between the first battery module 100 and the second battery module 200 within one cycle is completed; optionally, the energy storage unit 410 is a combined circuit unit of a coupled inductor and an energy storage capacitor, and the switch unit 420 is a switch unit composed of the same switch devices as the above-mentioned first switch tube.

[0079] The first balancing module 300 and the second balancing module 400 each have a balancing period of different period lengths.

[0080] In one embodiment, the energy storage unit 410 includes: a coupling inductor L and an energy storage capacitor C.

[0081] The first end of the coupling inductor L is connected to the positive terminal of a corresponding first battery module 100, and the second end of the coupling inductor L is connected to the negative terminal of a corresponding second battery module 200; the two ends of the energy storage capacitor C are respectively connected to the two ends of the coupling inductor L.

[0082] In one embodiment, the coupled inductor L includes: a first coupled inductor Li1 and a second coupled inductor Li2, the same-name end of the first coupled inductor Li1 is connected to the positive end of a corresponding first battery module 100, and the opposite-name end of the first coupled inductor Li1 is respectively connected to the first end of the energy storage capacitor and the first end of the switch unit 420; the same-name end of the second coupled inductor Li2 is connected to the negative end of a corresponding second battery module 200, and the opposite-name end of the second coupled inductor Li2 is respectively connected to the second end of the energy storage capacitor C and the second end of the switch unit 420.

[0083] In one embodiment, the energy storage capacitor C includes: a first capacitor Ci1 and a second capacitor Ci2, wherein the two ends of the first capacitor Ci1 are respectively connected to the opposite ends of the first coupling inductor Li1 and the opposite ends of the second coupling inductor Li2; the first end of the second capacitor Ci2 is connected to the negative end of a corresponding first battery module 100, and the second end of the second capacitor Ci2 is connected to the positive end of a corresponding second battery module 200.

[0084] In one embodiment, the switch unit 420 includes: a second switch tube Si1 and a third switch tube Si2, wherein the first end of the second switch tube Si1 is respectively connected to the opposite-name end of the first coupling inductor Li1 and the first end of the first capacitor Ci1, and the second end of the second switch tube Si1 is connected to the first end of the second capacitor Ci2; the first end of the third switch tube Si2 is respectively connected to the opposite-name end of the second coupling inductor Li2 and the second end of the first capacitor Ci1, and the second end of the third switch tube Si2 is connected to the second end of the second capacitor Ci2; wherein the second end of the second switch tube Si1 of the last second balancing module 400 is directly connected to the second end of the third switch tube Si2.

[0085] Among them, when the voltage difference between the two first battery modules 100 and the second battery module 200 correspondingly connected to any second balancing module 400 meets the preset condition, within one balancing cycle, the second switch tube Si1 is first closed, and the third switch tube Si2 is turned off, and the flow direction of the charge and discharge current between the first battery module 100 and the second battery module 200 is switched, so that part of the energy of the high-energy battery module is transferred to the first coupling inductor Li1, and the battery energy is transferred to the low-energy battery module through the induced current of the second coupling inductor Li2 and the energy storage capacitor C; then the second switch tube Si1 is turned off, and the third switch tube Si2 is closed, and the energy stored in the first coupling inductor Li1 continues to transfer energy to the low-energy battery module through the second coupling inductor Li2, and at the same time, the first coupling inductor Li1 transfers energy to the energy storage capacitor through the induced current together with the high-energy battery module, until the voltage difference between the two first battery modules 100 and the second battery module 200 is within the preset range, the energy balance between the first battery module 100 and the second battery module 200 within one cycle is completed, thereby realizing the energy transfer between PACKs, and greatly improving the overall balancing efficiency.

[0086] Among them, in the last second balancing module 400, only the first capacitor Ci1 of the energy storage capacitor C participates in the energy transfer of charging and discharging, and the rest of the balancing process is the same as the working process of the other second balancing modules mentioned above.

[0087] In one embodiment, the energy storage battery balancing circuit further includes: a control module (not shown in the above figure).

[0088] The control module is respectively connected to the gate of each switch tube (not shown in the above figure), and is used to control the closing and opening of each switch tube when the voltage difference between any two battery modules meets the preset conditions, so as to switch the flow direction of the charging and discharging current between any two battery modules.

[0089] Optionally, the control module may be, for example, a device for outputting a level signal (such as an external power supply, etc.), and controls the on and off of the switch tube by outputting a high level or low level signal to the gate of the switch tube.

[0090] In one embodiment, the equalization mode 1 of the first equalization module 300 is as follows: Figure 4 Shown: t z0 -t z1 At this moment, the switch tube S1 is turned on, S2, S3...S n The battery unit B1, inductor L1 and switch tube S1 form a loop. At this time, B1 charges the inductor L1 through the loop, and the current on the inductor L1 rises linearly until t z1 At this moment, the current on the inductor L1 reaches its peak value. B1 and i L1 The actual current direction is opposite to the reference direction.

[0091] In one embodiment, the equalization mode 2 of the first equalization module 300 is as follows: Figure 5 Shown: t z1 -t z2 At this moment, the switch tube S1 is turned off, S2, S3, ... n At this time, the inductor L1 is in the discharge state, and the battery unit B2, the inductor L1, the body diode of the switch tube S2, and the inductor L2 form a loop; B3, the inductor L2, the body diode of the switch tube S3, and the inductor L3 form a loop...B n 、Inductance L n-1 , switch tube S n Therefore, the energy in the inductor L1 is respectively transferred to the inductors L2, L3, ... L n-1 and battery cell B i+1 Charge.

[0092] In one embodiment, the equalization mode 3 of the first equalization module 300 is as follows: Figure 6 Shown: t z2 -t z3 At this moment, the switch tubes S1, S2...S n At this time, the inductor L1 continues to discharge. n The role of the body diode, at t z3 At this moment, the battery current i Bn When it drops to 0, this circuit stops working, and the working status of other circuits is similar.

[0093] In one embodiment, the equalization mode n of the first equalization module 300 is as follows: Figure 7 Shown: t z(n-1) -t znAt this moment, the switch tubes S1, S2...S n Still remain off. At this time, the inductor L1 continues to discharge, and the current further decreases. Finally, due to the action of the body diode of the switch tube S2, until t zn At this moment, the battery current i B2 When it drops to 0, this loop stops working, that is, one cycle of balancing work is completed.

[0094] In one embodiment, the operating waveform of the first equalization module 300 during equalization is as follows: Figure 8 As shown, the waveform represents the current change of the inductor L1 when the first battery modules are balanced within a complete cycle. During the balance, the driving signal of the switch tube S1 is UGS1.

[0095] In one embodiment, the equalization mode 1 of the second equalization module 400 is as follows: Fig. 9 As shown: At t0-t1, the switch tube S i1 Turn on, switch tube S i2 Shutdown. Coupled inductor L i1 , S i1 and battery cell B i Form a loop, B i Give the coupled inductor L i1 At the same time, the coupled inductor L i2 The current is induced from right to left, and L i2 , capacitor C i1 , S i1 , C i2 and battery B n-i+1 So, L i2 With capacitor C i1 , C i2 Commonly through the circuit to battery B n-i+1 and L i2 Charge.

[0096] In one embodiment, the equalization mode 2 of the second equalization module 400 is as follows: Fig.10 As shown: at t1-t2, the switch tube S i1 Turn off, switch S i2 The coupled inductor L i2 , S i2 and battery cell B n-i+1 The loop is formed and stored in L i1 The energy is given to B through the circuit n-i+1 At the same time, the coupled inductor L i1 The current from left to right is induced, and B i , coupled inductor L i1 , capacitor C i1 , S i2 and Ci2 Therefore, B i With L i1 Through the loop to the capacitor C i1 , C i2 Charge.

[0097] In one embodiment, the equalization mode of the nth second equalization module 400 is as follows: Fig.11 , Fig.12 As shown: The working principle is basically the same as that of the i-th lateral Cuk circuit. The biggest difference between the two is that the n-th lateral Cuk circuit lacks a capacitor and only has one capacitor C n1 Participate in charging and discharging, and its specific balancing process will not be repeated here.

[0098] In one embodiment, the operating waveform of the second equalization module 400 during equalization is as follows: Fig.13 As shown, the waveform represents the current change of the coupled inductor when the first battery module 100 and the second battery module 200 are balanced during a complete cycle. During the balance, the driving signals of the switch tubes Si1-Si2 and Sn1-Sn2 are UGSi1-UGSi2 and UGSn1-UGSn2 respectively.

[0099] The embodiment of the present application also provides an energy storage battery equalizer, including the energy storage battery equalization circuit of the above embodiment. The energy storage battery equalizer of this embodiment can achieve energy balance in two directions at the same time, thereby reducing energy loss, shortening the energy transfer path, improving the utilization rate and service life of battery energy, and reducing a set of switch tubes and inductors, thereby reducing the use cost of the equalizer.

[0100] Fig.14 This is a flow chart of a method for balancing energy storage batteries according to an embodiment of the present invention. Fig.14 The energy storage battery balancing method is applied to an energy storage battery equalizer, and the energy storage battery balancing method includes step 142.

[0101] Step 142, when the voltage difference between any two battery modules meets the preset condition, control the first balancing module to switch the flow direction of the charge and discharge current between the first battery modules so that the voltage difference between the first battery modules is within a preset range; and control the second balancing module to switch the flow direction of the charge and discharge current between each first battery module and the corresponding second battery module so that the voltage difference between any first battery module and the corresponding second battery module is within a preset range.

[0102] Among them, step 142 can be executed by the control module in the above embodiment. For relevant features of the control module, the first battery module, the second battery module, the first balancing module, the second balancing module, etc., please refer to the relevant introduction in the above embodiment, which will not be repeated here.

[0103] The energy storage battery balancing method provided in this embodiment controls the first balancing module to switch the flow direction of the charge and discharge current between the first battery modules and controls the second balancing module to switch the flow direction of the charge and discharge current between the first battery modules and the corresponding second battery module when the voltage difference between any two battery modules meets the preset condition, so that the voltage difference between any two battery modules is within the preset range, and energy balancing in two directions can be achieved simultaneously, thereby reducing energy loss, shortening the energy transfer path, and improving the utilization rate and service life of battery energy.

[0104] It should be understood that, although each step in the flow chart of the above-described embodiment is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flow chart of the above-described embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0105] The present application may also provide an energy storage battery balancing device of an embodiment, which is applied to an energy storage battery equalizer. The energy storage battery balancing device is used to control the first balancing module 300 to switch the flow direction of the charge and discharge current between the first battery modules 100 when the voltage difference between any two battery modules meets a preset condition, so that the voltage difference between the first battery modules 100 is within a preset range; and control the second balancing module 400 to switch the flow direction of the charge and discharge current between each first battery module and the corresponding second battery module, so that the voltage difference between any first battery module 100 and the corresponding second battery module 200 is within a preset range.

[0106] The energy storage battery balancing device provided in this embodiment controls the first balancing module 300 to switch the flow direction of the charge and discharge current between the first battery modules 100 when the voltage difference between any two battery modules meets the preset condition, so that the voltage difference between the first battery modules 100 is within a preset range; controls the second balancing module 400 to switch the flow direction of the charge and discharge current between each first battery module 100 and the corresponding second battery module 200, so that the voltage difference between any first battery module 100 and the corresponding second battery module 200 is within the preset range, and can simultaneously achieve energy balancing in two directions, thereby reducing energy loss, shortening the energy transfer path, and improving the utilization rate and service life of battery energy.

[0107] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0108] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A storage battery equalization circuit, characterized in that: include: A plurality of first battery modules connected in series and a plurality of second battery modules connected in series; A first balancing module is connected to the positive terminal and the negative terminal of each of the first battery modules respectively; A plurality of second balancing modules, wherein the two first ends of each of the second balancing modules are respectively connected to the positive terminal and the negative terminal of one of the first battery modules, and the two second ends of each of the second balancing modules are respectively connected to the positive terminal and the negative terminal of one of the second battery modules; Wherein, each of the first battery modules and a corresponding second battery module share one second balancing module; when the voltage difference between any two battery modules meets a preset condition, the first balancing module is used to switch the flow direction of the charge and discharge current between each of the first battery modules, so that the voltage difference between the first battery modules is within a preset range; each of the second balancing modules is used to switch the flow direction of the charge and discharge current between each of the first battery modules and the corresponding second battery module, so that the voltage difference between any of the first battery modules and the corresponding second battery module is within a preset range; Wherein, the second balancing module comprises: An energy storage unit, wherein two first ends of the energy storage unit are connected to a positive end of the first battery module, a second end of the energy storage unit is connected to a negative end of the first battery module, a third end of the energy storage unit is connected to a negative end of the second battery module, and a fourth end of the energy storage unit is connected to a positive end of the second battery module, and is used to receive electric energy transmitted by a battery module at a high voltage when a voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, and release and transmit the electric energy to a battery module at a low voltage, so that the voltage difference between any two of the first battery modules and the second battery modules is within a preset range; A switch unit, wherein the first end of the switch unit is connected to the second end of the energy storage unit, and the second end of the switch unit is connected to the fourth end of the energy storage unit, and is used to close or open when the voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, so as to switch the direction of the charge and discharge current between each of the first battery modules and each of the second battery modules.

2. The energy storage battery equalization circuit according to claim 1, characterized in that: The first equalization module comprises: A plurality of first balancing units, wherein the first ends of each of the first balancing units are connected to each other, and the second ends of each of the first balancing units are respectively connected to the positive terminal and the negative terminal of a first battery module, and are used to switch the flow direction of the charge and discharge current between the first battery modules when the voltage difference between any two of the first battery modules meets a preset condition, so that the voltage difference between any two of the first battery modules is within a preset range.

3. The energy storage battery equalization circuit according to claim 2, characterized in that: The first equalizing unit comprises: an energy storage inductor, wherein a first end of the energy storage inductor is respectively connected to a negative terminal of a corresponding one of the first battery modules and a positive terminal of another first battery module connected in series to the corresponding one of the first battery modules, and a voltage value of another first battery module is lower than that of the corresponding one of the first battery modules; A first switch tube, wherein the first switch tubes of each of the first balancing units are connected in series, and a first end of each of the first switch tubes is further connected to a second end of the corresponding energy storage inductor; The second end of the first switch tube of the first first balancing unit is connected to the positive terminal of a corresponding first battery module, and the second end of the first switch tube of the last first balancing unit is connected to the negative terminal of a corresponding first battery module.

4. The energy storage battery equalization circuit according to claim 1, characterized in that: The energy storage unit comprises: A coupled inductor, wherein a first end of the coupled inductor is connected to a positive terminal corresponding to the first battery module, and a second end of the coupled inductor is connected to a negative terminal corresponding to the second battery module; An energy storage capacitor, wherein two ends of the energy storage capacitor are respectively connected to two ends of the coupling inductor.

5. The energy storage battery equalization circuit according to claim 4, characterized in that: The coupled inductor comprises: A first coupled inductor, wherein a like-name end of the first coupled inductor is connected to a positive terminal of a corresponding first battery module, and an opposite-name end of the first coupled inductor is respectively connected to a first end of the energy storage capacitor and a first end of the switch unit; A second coupled inductor, wherein the same-name end of the second coupled inductor is connected to the negative terminal of a corresponding second battery module, and the opposite-name end of the second coupled inductor is respectively connected to the second end of the energy storage capacitor and the second end of the switch unit.

6. The energy storage battery equalization circuit according to claim 5, characterized in that: The energy storage capacitor comprises: A first capacitor, wherein two ends of the first capacitor are respectively connected to opposite-name ends of the first coupled inductor and opposite-name ends of the second coupled inductor; A second capacitor, wherein a first end of the second capacitor is connected to a negative end of a corresponding first battery module, and a second end of the second capacitor is connected to a positive end of a corresponding second battery module.

7. The energy storage battery equalization circuit according to claim 6, characterized in that: The switch unit comprises: a second switch tube, wherein a first end of the second switch tube is respectively connected to the opposite-name end of the first coupled inductor and the first end of the first capacitor, and a second end of the second switch tube is connected to the first end of the second capacitor; a third switch tube, wherein a first end of the third switch tube is respectively connected to the opposite-name end of the second coupled inductor and the second end of the first capacitor, and a second end of the third switch tube is connected to the second end of the second capacitor; Wherein, the second end of the second switch tube of the last second balancing module is directly connected to the second end of the third switch tube.

8. The energy storage battery equalization circuit according to claim 7, characterized in that: Also includes: The control module is respectively connected to the gate of each switch tube, and is used to control the closing and opening of each switch tube when the voltage difference between any two of the battery modules meets a preset condition, so as to switch the flow direction of the charge and discharge current between any two of the battery modules.

9. An energy storage battery equalizer, characterized in that: The invention comprises an energy storage battery equalization circuit as claimed in any one of claims 1 to 8.

10. A method for balancing an energy storage battery, characterized in that: Applied to an energy storage battery equalizer, the energy storage battery equalization method includes: When the voltage difference between any two battery modules meets a preset condition, controlling the first balancing module to switch the flow direction of the charge and discharge current between the first battery modules so that the voltage difference between the first battery modules is within a preset range; and controlling the second balancing module to switch the flow direction of the charge and discharge current between each of the first battery modules and the corresponding second battery modules, so that the voltage difference between any of the first battery modules and the corresponding second battery modules is within a preset range; Wherein, the second balancing module comprises: An energy storage unit, wherein two first ends of the energy storage unit are connected to a positive end of the first battery module, a second end of the energy storage unit is connected to a negative end of the first battery module, a third end of the energy storage unit is connected to a negative end of the second battery module, and a fourth end of the energy storage unit is connected to a positive end of the second battery module, and is used to receive electric energy transmitted by a battery module at a high voltage when a voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, and release and transmit the electric energy to a battery module at a low voltage, so that the voltage difference between any two of the first battery modules and the second battery modules is within a preset range; A switch unit, wherein the first end of the switch unit is connected to the second end of the energy storage unit, and the second end of the switch unit is connected to the fourth end of the energy storage unit, and is used to close or open when the voltage difference between any two of the first battery modules and the second battery modules meets a preset condition, so as to switch the direction of the charge and discharge current between each of the first battery modules and each of the second battery modules.

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