An equalization circuit and vehicle

Abstract

The application provides a balancing circuit and a vehicle, which comprises a closed magnetic core, a winding wound on the closed magnetic core, the winding being adapted to simultaneously connect a first battery cell and a second battery cell in series, and the polarity direction of the first battery cell and the second battery cell being opposite, and a switch tube assembly arranged between the winding and the first battery cell and between the winding and the second battery cell, and used for controlling mutual transfer of the electric quantity of the first battery cell and the electric quantity of the second battery cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, and more particularly to a balancing circuit and a vehicle. BACKGROUND

[0002] At present, the battery pack of an electric vehicle is greatly reduced in service life due to the use environment, personal habits, long-term placement, overheating and other reasons. One of the reasons is that it is difficult to ensure the consistency of large-scale series-parallel battery packs in use.

[0003] Poor battery consistency can lead to reduced battery charging and discharging performance, and some battery units in the battery pack may be overcharged or overdischarged. Lightly, it can cause battery damage and further shorten the service life of the battery; heavily, it can cause the battery to overheat and cause fire or explosion risk, greatly affecting user experience and even affecting driving safety.

[0004] In view of the above technical problems, the present application provides a new balancing circuit and a vehicle to at least partially solve the above problems. SUMMARY

[0005] The present application is proposed to solve at least one of the above problems. According to an aspect of the present application, a balancing circuit is provided, comprising:

[0006] A closed magnetic core;

[0007] A winding wound around the closed magnetic core, the winding being adapted to simultaneously connect a first cell and a second cell in series, and the polarity direction connected with the first cell and the second cell being opposite;

[0008] A switch tube assembly arranged between the winding and the first cell and between the winding and the second cell, for controlling the mutual transfer of the electric quantity of the first cell and the electric quantity of the second cell.

[0009] In some embodiments, a first potential end of the winding is connected to the positive electrode of the first cell and the negative electrode of the second cell, and a second potential end of the winding is connected to the negative electrode of the first cell and the positive electrode of the second cell.

[0010] In some embodiments, the switch tube assembly includes a first switch tube and a second switch tube, the first switch tube being arranged between the winding and the first cell, and the second switch tube being arranged between the winding and the second cell;

[0011] The first switch tube and the second switch tube are configured to be alternately turned on and turned off, so that when the first switch tube is turned on and the second switch tube is turned off, the electric quantity of the first cell can be transferred to the second cell; when the second switch tube is turned on and the first switch tube is turned off, the electric quantity of the second cell can be transferred to the first cell.

[0012] In some embodiments, the first end of the first switch tube is connected to the second potential end of the winding, the second end of the first switch tube is connected to the negative pole of the first battery cell, and the first switch tube further comprises a control end adapted to be connected to the controller.

[0013] The first end of the second switch tube is connected to the second potential end of the winding, the second end of the second switch tube is connected to the positive pole of the second battery cell, and the second switch tube further comprises a control end adapted to be connected to the controller.

[0014] In some embodiments, when the first switch tube connected to the first battery cell is turned on, and the second switch tube connected to the first battery cell, the first switch tube connected to the second battery cell, and the second switch tube connected to the second battery cell are all turned off, the electric quantity of the first battery cell is transferred to the second battery cell through the first switch tube connected to the second battery cell.

[0015] When the first switch tube connected to the first battery cell, the second switch tube connected to the first battery cell, the first switch tube connected to the second battery cell, and the second switch tube connected to the second battery cell are all turned off, the freewheeling of the winding is charged back to the first battery cell through the second switch tube connected to the first battery cell.

[0016] When the second switch tube connected to the first battery cell is turned on, and the first switch tube connected to the first battery cell, the first switch tube connected to the second battery cell, and the second switch tube connected to the second battery cell are turned off, the electric quantity of the first battery cell is transferred to the second battery cell through the second switch tube connected to the second battery cell.

[0017] In some embodiments, the first switch tube is equivalent to a first switch element and a first diode connected in parallel, and the second switch tube is equivalent to a second switch element and a second diode connected in parallel.

[0018] In some embodiments, the equalization circuit comprises a plurality of windings and a plurality of switch tube assemblies, and each winding has the same number of turns.

[0019] In some embodiments, any two windings of the plurality of windings are adapted to be connected to the same battery cell in a series connection, and the polarities of the connection of the any two windings and the same battery cell are opposite.

[0020] In some embodiments, the equalization circuit further comprises a charging winding wound on a closed magnetic core along the circumferential direction of the closed magnetic core, and the two ends of the charging winding are connected to a power supply; wherein the switch tube assembly is further used to control the electric quantity provided by the charging winding to be transferred to the first battery cell and / or the second battery cell, so as to equalize the electric quantity of the first battery cell and the electric quantity of the second battery cell.

[0021] In some embodiments, a plurality of freewheeling inductors are further included, and the winding is connected to the first battery cell and the second battery cell through at least one freewheeling inductor.

[0022] In some embodiments, a first end of the at least one freewheeling inductor is connected to a first potential end of the winding, and a second end of the at least one freewheeling inductor is connected to a positive electrode of the first battery cell and a negative electrode of the second battery cell; and / or a first end of the at least one freewheeling inductor is connected to a second potential end of the winding, and a second end of the at least one freewheeling inductor is connected to a negative electrode of the first battery cell and a positive electrode of the second battery cell.

[0023] In yet another aspect, the application provides a vehicle comprising a battery and the above-mentioned balancing circuit.

[0024] The balancing circuit and the vehicle according to the embodiments of the application use a closed magnetic core and a plurality of windings arranged on the closed magnetic core as a medium for electric quantity transmission. The closed magnetic core has the characteristics of magnetic circuit closure and small magnetic leakage. The transformer made by using these characteristics has the characteristics of small leakage inductance, good synchronization, and high working efficiency. In the whole balancing circuit, the synchronization control of the conduction or turn-off of the first switch tube and the second switch tube corresponding to each winding is used to selectively balance the battery cells that need to be balanced. The unbalanced electric quantity of the series-connected battery cells is synchronously transmitted to the balancing through the windings on the closed magnetic core. The consistency of the battery cells is better through the balancing of the battery cells. The problem of the decline of the vehicle endurance caused by the poor consistency is avoided. The service life of the battery is improved. The endurance and safety of the battery are improved. The driving safety is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and other objects, features and advantages of the application will become more apparent from the following detailed description of the application when taken in conjunction with the accompanying drawings. The drawings provided in the specification and the contents of the specification are part of the description and serve to explain the application together with the embodiments of the application and do not constitute a limitation on the application. In the drawings, the same reference numerals generally designate the same components or steps.

[0026] Figure 1 A schematic topological diagram of a balancing circuit according to an embodiment of the application is shown. The left diagram is a balancing circuit of a three-battery power supply in series before evolution. The right diagram is a topological diagram of the expansion of the number of series-connected battery cells to n+1. The distribution of the ring-shaped magnetic core and the windings is shown.

[0027] Figure 2 A schematic diagram of the electric quantity transmission of battery cell B1 according to an embodiment of the application is shown.

[0028] Figure 3 A schematic diagram of the electric quantity transmission of battery cell B1 to battery cell B3 according to an embodiment of the application is shown.

[0029] Figure 4 A timing diagram of the in-phase switch driving according to an embodiment of the application is shown.

[0030] Figure 5A timing diagram of in-phase variable duty cycle driving is shown according to an embodiment of the present application.

[0031] Figure 6 A schematic diagram of an equalization circuit is shown according to another embodiment of the present application.

[0032] Figure 7 A schematic diagram of an equalization circuit is shown according to yet another embodiment of the present application.

[0033] Figure 8 A schematic diagram is shown according to an embodiment of the present application when the shape of the closed magnetic core is an ellipse. DETAILED DESCRIPTION

[0034] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present application. However, it will be apparent to one of skill in the art upon

[0035] It should be understood that the present application can be embodied in different forms without departing from the spirit or central characteristics thereof. The present embodiments are to be considered in a descriptive sense only and not for purposes of limitation. The scope of the present application is therefore indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.

[0036] It will be understood that when an element or layer is referred to as being "on" or "adjacent" or "connected" or "coupled" to another element or layer, it can be directly on, adjacent, connected or coupled to the other element or layer or one or more intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on," "directly adjacent," "directly connected" or "directly coupled" to another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0037] For a more complete understanding of the present application, reference is made to the following description and accompanying drawings that set forth various embodiments of the present application. In the description of embodiments of the present application reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments by which the application can be practiced. The embodiments of the present application are described in sufficient detail to enable those skilled in the art to practice the application, and it is to be understood that other embodiments can be utilized and that structural, logical and electrical changes can be made without departing from the scope of the present application. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present application is indicated by the appended claims and their equivalents.

[0038] Reference will now be made to Figures 1 to 8 An equalization circuit according to one embodiment of the present application is described.

[0039] As Figure 1 shown, the present application provides an equalization circuit, a battery includes a plurality of battery cells B1, B2, B3, …, Bn, Bn+1 connected in series, n is a natural number series, the battery cell can be a single battery cell, or it can also be a battery pack after a plurality of single battery cells are connected in series, for example, 2, 3, or 4 single battery cells are connected in series, in some other embodiments, the battery cell can also be an energy storage capacitor, etc.

[0040] Continuing to refer to Figure 1 , the equalization circuit includes a closed magnetic core CL1, which can be any suitable ring shape, such as a circular ring, an elliptical ring (as Figure 8 shown), a rectangular ring, etc., wherein preferably the closed magnetic core is a circular ring. The closed magnetic core CL1 can be made of ferrite or other types of high-frequency magnetic cores, and its switching frequency is related to the material.

[0041] Further, the equalization circuit further includes a plurality of windings, each winding being wound around the closed magnetic core, the plurality of windings T0, T1, T2, T3, T4, …, Tn, Tn+1, the plurality of windings being wound around the closed magnetic core in sequence along the circumferential direction of the closed magnetic core, and adjacent two windings being opposite windings, specifically, the winding is adapted to be connected to a first battery cell and a second battery cell in series at the same time, and the polarity direction connected with the first battery cell and the second battery cell is opposite, for example, the winding is adapted to be connected to the first battery cell in forward direction and to the second battery cell in reverse direction, and the first battery cell and the second battery cell are connected in series. Optionally, the number of turns of each winding is the same. Optionally, the number of windings is one more than the number of battery cells.

[0042] Further, the equalization circuit further includes a switch tube assembly, which is arranged between the winding and the first battery cell, and between the winding and the second battery cell, for transferring the electric quantity of the first battery cell and the electric quantity of the second battery cell to each other.

[0043] In some embodiments, the switch tube assembly includes a first switch tube and a second switch tube, the first switch tube is arranged between the winding and the first battery cell, and the second switch tube is arranged between the winding and the second battery cell, the first switch tube and the second switch tube are configured to be alternately turned on and turned off, so that when the first switch tube is turned on and the second switch tube is turned off, the electric quantity of the first battery cell can be transferred to the second battery cell; when the second switch tube is turned on and the first switch tube is turned off, the electric quantity of the second battery cell can be transferred to the first battery cell. The closed magnetic core and the plurality of windings arranged on the closed magnetic core are used as the medium for electric quantity transmission, the closed magnetic core has the characteristics of magnetic circuit closure and small magnetic leakage, and the transformer made by using these characteristics has the characteristics of small leakage inductance, good synchronization, high work efficiency, etc. In the entire balancing circuit, the corresponding first switch tube and second switch tube of each winding are synchronously controlled to be turned on or turned off, and the battery cells that need to be balanced are selectively balanced, the unbalanced electric quantity of the series-connected battery cells is synchronously transferred to the balancing through the windings on the closed magnetic core, the battery cells are balanced, the consistency is better, the problem of vehicle endurance degradation due to poor consistency is avoided, the service life of the battery is improved, the endurance and safety of the battery are improved, and the driving safety is improved.

[0044] In some embodiments, the balancing circuit includes a plurality of first switch tubes QA1, QA2, …, QAn+1. The first switch tube can be a MOS tube (such as NMOS or PMOS) or other suitable switch tube, wherein the first switch tube can be equivalent to a parallel connection of a switch element and a diode, and the first switch tube can be controlled by a control signal of a controller to be turned on or turned off.

[0045] Further, the balancing circuit also includes a plurality of second switch tubes, each second switch tube can include a second switch tube, and the balancing circuit includes a plurality of second switch tubes QB1, QB2, …, QBn+1. The second switch tube can be a MOS tube or other suitable switch tube, wherein the second switch tube can be equivalent to a parallel connection of a switch element and a diode, and the control end of the second switch tube can be connected to a controller, which can be controlled by a control signal of the controller to be turned on or turned off.

[0046] Each battery cell is connected to a winding via a second switch tube, each battery cell is connected to different two windings in the plurality of windings, that is, connected to one winding via a first switch tube and connected to another winding via a second switch tube, and the two windings connected by each battery cell are opposite windings. In some embodiments, the first potential end (such as the low potential end) of the winding is connected to the positive electrode of the first battery cell and the negative electrode of the second battery cell, and the second potential end (such as the high potential end) of the winding is connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell. The connection between the winding and the positive electrode and the negative electrode of the battery cell can be direct connection or indirect connection (such as connection through the first switch tube or the second switch).

[0047] In some embodiments, the first end of the first switch tube is connected to the second potential end of the corresponding winding, the first end of the first switch tube is connected to the second potential end of the winding, the second end of the first switch tube is connected to the negative electrode of the first battery cell, the first switch tube further comprises a control end, and the control end of the first switch tube is connected to the controller; the first end of the second switch tube is connected to the second potential end of the winding, the second end of the second switch tube is connected to the positive electrode of the second battery cell, the second switch tube further comprises a control end, and the control end of the second switch tube is connected to the controller. In some embodiments, the first switch tube can be equivalent to a parallel connection of a switch element and a diode, and the second switch tube can be equivalent to a parallel connection of a switch element and a diode. Then, in some embodiments, the positive electrode of the diode of the first switch tube is connected to the negative electrode of the first battery cell, and the negative electrode of the diode of the first switch tube is connected to the second potential end of the winding; the positive electrode of the diode of the second switch tube is connected to the second potential end of the winding, and the negative electrode of the diode of the second switch tube is connected to the positive electrode of the second battery cell.

[0048] In some embodiments, the equalization circuit further comprises a controller connected to the control end of each first switch tube and the control end of each second switch tube, for controlling the conduction or closing (i.e. opening) of the first switch tube and the second switch tube, so as to transfer the electric quantity of the high-voltage battery cell in the plurality of battery cells to the low-voltage battery cell in the plurality of battery cells through the closed magnetic core, thereby achieving voltage balance between the plurality of battery cells.

[0049] In one specific embodiment, the equalization circuit comprises a closed magnetic core CL1, windings T (optionally, the number of turns of each winding is the same) on the closed magnetic core, and battery cells B, first switch tubes QA and second switch tubes QB, which form a cascaded series battery equalization system. The winding T0 is a compensation winding for compensating the magnetic reset current of the first battery cell B1. The winding T1 on the closed magnetic core and the first switch tube QA1 and the second switch tube QB1 connected thereto and the battery cell B1 are the smallest working unit of the equalization system. The working principle is to use the characteristics of the closed magnetic core, such as closed magnetic circuit, small magnetic leakage, and high efficiency, to use the full-bridge transformer wound thereon to have the characteristics of uniform winding distribution, good coupling, and good synchronization. The control strategy is used to synchronously (in phase) control the conduction (sometimes also referred to as turn-on in this paper) and closing of the first switch tube QA and the second switch tube QB of each unit, and the equalization current of the battery cell is adjusted by adjusting the conduction duty ratio of the first switch tube QA and the second switch tube QB of the smallest unit. The switching duty ratio of the unit with excessively high or low voltage is high, and the switching duty ratio of the unit that has reached or is close to balance is small or closed, so that the fast equalization of the unbalanced electric quantity can be achieved. Some specific details will be described in detail below with reference to the accompanying drawings.

[0050] The present application will be described in detail below with reference to the accompanying drawings and specific implementation methods. Figure 1The left side is the equalization principle diagram of the series battery, wherein the equalization circuit further comprises a plurality of windings T0, T1, T2, T3, T4, …, Tn, Tn+1, the T0 winding is an independent winding, used to compensate the reverse magnetic reset current of the T1 winding, and so on, the T0 winding is the reverse winding of the T1 winding, the T1 winding is the reverse winding of the T2 winding, …, the Tn+1 winding is the reverse winding of the Tn winding.

[0051] As shown in Figure 1 The plurality of battery cells comprises battery cell B1 and battery cell B2, and the exemplary connection mode between the battery cells, windings and switching circuits is described taking the battery cells B1 and B2 in the plurality of battery cells as examples, wherein the battery cells B1 and B2 have a connection relationship with the windings T0 to T2, the first potential end (for example, the low potential end) of the winding T1 is connected to the positive electrode of the battery cell B1 and the negative electrode of the battery cell B2, and the second potential end (for example, the high potential end) of the winding T1 is connected to the negative electrode of the battery cell B1, for example, the second potential end of the winding T1 is connected to the negative electrode of the body diode of the first switching tube QA1 through the first switching tube QA1, more specifically, the second potential end of the winding T1 is connected to the negative electrode (corresponding to the drain of the first switching tube QA1) of the body diode of the first switching tube QA1, the positive electrode of the body diode of the first switching tube QA1 is connected to the positive electrode (corresponding to the source of the first switching tube QA1) of the battery cell B1, and the control end (for example, the gate) of the first switching tube QA1 is connected to the controller, and the second potential end of the winding T1 is also connected to the positive electrode of the battery cell B2 through the second switching tube QB2, specifically, the second potential end of the winding T1 is connected to the positive electrode (corresponding to the source of the second switching tube QB2) of the diode (sometimes also referred to as the body diode) of the second switching tube QB2, the negative electrode (corresponding to the drain of the second switching tube QB2) of the body diode of the second switching tube QB2 is connected to the positive electrode of the battery cell B2, and the control end (for example, the gate) of the second switching tube QB2 is connected to the controller, the first potential end of the winding T0 is connected to the negative electrode of the battery cell B1, and the second potential end of the winding T0 is connected to the positive electrode of the battery cell B1, for example, the second potential end of the winding T0 is connected to the positive electrode of the battery cell B1 through the second switching tube, for example, the second switching tube QB1, specifically, the second potential end of the winding T0 is connected to the positive electrode (corresponding to the source of the second switching tube QB1) of the body diode of the second switching tube QB1, and the negative electrode (for example, corresponding to the drain of the second switching tube QB1) of the body diode of the second switching tube QB1 is connected to the positive electrode of the battery cell B1, and the winding T1 and the winding T0 are reverse windings through such a connection mode. Further, the first potential end of the winding T2 is connected to the positive electrode of the battery cell B2 and the negative electrode of the battery cell B3, and the second potential end of the winding T2 is connected to the negative electrode of the battery cell B2, for example, the second potential end of the winding T2 is connected to the negative electrode of the body diode of the first switching tube QA2 through the first switching tube, for example, the first switching tube QA2, specifically, the second potential end of the winding T2 is connected to the negative electrode of the body diode of the first switching tube QA2, and the positive electrode of the body diode of the first switching tube QA2 is connected to the positive electrode of the battery cell B2.

[0052] Other battery cells and corresponding windings in series can also be connected in a substantially similar manner.

[0053] Taking one basic unit of the balancing circuit as an example, the basic unit includes winding T1, first switch tube QA1, second switch tube QB1 and battery cell B1. For the convenience of understanding, the first switch tube and the second switch tube are replaced by the structure of a switch element in parallel with a diode, as shown in Figure 2 Several working conditions of the balancing circuit are explained and described.

[0054] Exemplarily, the controller is connected to the control end of the first switch tube and the control end of the second switch tube, for controlling the first switch tube and the second switch tube to be adapted to alternatingly turn on and turn off. Specifically, the controller is further configured to control the first switch tube connected to the battery cell to be balanced (the battery cell to be balanced can refer to a battery cell with higher electric quantity and a battery cell with lower electric quantity) to be turned on in a first time, and control the second switch tube connected to the battery cell to be balanced to be turned off in the first time, so as to make the battery cell to be balanced supply power to the winding connected thereto. Each winding on the annular magnetic core senses a corresponding electromotive force. When the electromotive force at both ends of the winding is greater than the voltage of the battery cell connected to the winding, the battery cell connected to the winding is charged.

[0055] Reference is made to Figure 2 Several working conditions of the circuit are described. Taking the balancing minimum unit of battery cell B1 as an example, reference is made to the standby state. When the balancing circuit is in the standby state, the first switch tube QA1 and QA2 are both in the off state. The current of the positive electrode of battery cell B1 and the positive electrode of battery cell B2 is cut off at the body diode of the first switch tube QA1 and QA2, respectively, and a loop cannot be formed. At this time, the entire balancing system (i.e. the balancing circuit) is in the standby state or the balanced state.

[0056] Specifically, the electric quantity transfer process is as follows Figure 2As shown in state A, when the first switch QA1 is controlled to be turned on in the first time, the second switch QB1 is controlled to be turned off (turned off means disconnected, the two ends of the switch are not conductive) in the first time, the T1 winding loop is connected, the current of the battery B1 flows through the winding T1 and the first switch QA1, and the closing of other windings on the magnetic core will also induce corresponding electromotive force, but since the corresponding first switch (QA2 to QAn+1) of the other battery is not turned on, if the voltage difference is large, that is, when the electromotive force at both ends of the winding is greater than the voltage of the battery connected to the winding by a predetermined threshold, the battery connected to each first switch will be charged through the body diode of each first switch, and the magnetic core will be charged. Taking the battery B1 and the battery B2 as an example, when the first switch QA1 connected to the battery B1 is turned on, and the second switch QB1 connected to the battery B1, the first switch QA2 connected to the battery B2 and the second switch QB2 connected to the battery B2 are turned off, the electric quantity of the battery B1 is transferred to the second battery B2 through the first switch QA2 (for example, through the body diode of the first switch QA2) connected to the battery B2.

[0057] Further, the controller is further configured to: when the first time ends, control each first switch to be turned off and each second switch to be turned off in a second time, the freewheeling current generated by the winding is back-flushed to the corresponding battery through the second switch connected thereto, or the voltage between the two ends of each second switch included in the second switch is lower than a predetermined value (for example, the voltage between the two ends of the second switch is close to 0), for example, continue as shown in state B. Figure 2 As shown in state B, when the first time ends, the first switch QA1 is turned off, and each winding on the magnetic core needs freewheeling current, and the polarity is reversed, as shown in state B, the freewheeling current generated by the winding T0 is back-flushed to the battery B1 through the body diode of the second switch QB1 or makes the voltage between the two ends of the second switch QB1 close to 0V. Taking the battery B1 and the battery B2 as an example, when the first switch QA1 connected to the battery B1 is turned off, and the second switch QB1 connected to the battery B1, the first switch QA2 connected to the battery B2 and the second switch QB2 connected to the battery B2 are all turned off, the freewheeling current of the winding T0 is back-flushed to the battery B1 through the second switch QB1 (for example, the body diode of the second switch QB1) connected to the battery B1.

[0058] In some embodiments, the controller is further configured to control the second switch connected to the battery to be balanced in the plurality of batteries to be turned on in a third time, and control the first switch to be turned off, each winding on the magnetic core induces a corresponding electromotive force, when the electromotive force at both ends of the winding is greater than the voltage of the battery connected to the winding, the battery connected to the second switch is charged through the second switch, for example, continue to refer to state C. Figure 2When the voltage difference between the two ends of the QB1 is close to 0V, the second switch QB1 is controlled to be turned on, and the soft switching effect of the second switch QB1 is realized, as shown in "state C". Other windings on the ring-shaped magnetic core will also induce corresponding electromotive forces, but the corresponding second switches of other electric cores are not turned on. If the voltage difference is large (for example, when the electromotive force between the two ends of the winding is greater than the voltage of the electric core connected to the winding by a predetermined threshold), the other electric cores will be charged through the body diode of each second switch, and the magnetic core will be reversely energized. Taking the electric core B1 and the electric core B2 as an example, when the second switch QB1 connected to the electric core B1 is turned on, the first switch QA1 connected to the electric core B1 is turned off, and the first switch QA2 connected to the electric core B2 and the second switch QB2 connected to the electric core B2 are both turned off, the electric quantity of the electric core B1 is transferred to the electric core B2 through the second switch QB2 (for example, the body diode of the second switch QB2) connected to the electric core B2.

[0059] In some embodiments, the controller is further configured to: when the third time ends, control each first switch to be closed and each second switch to be closed within a fourth time, or the voltage between the two ends of each first switch is lower than a predetermined value (for example, the voltage between the two ends of the first switch is close to 0), so that the freewheeling current generated by the winding is back-flushed to the corresponding electric core through the first switch connected thereto. For example, as shown in the following figure, when the third time ends, the second switch QB1 is turned off, and each first switch is kept closed. The winding on the magnetic core generates a freewheeling current, and the polarity is reversed again. The polarity of all windings is shown in "state D". The freewheeling current generated by each winding can be back-charged to the corresponding electric core through the body diode of the corresponding first switch, or the voltage between the two ends of each first switch is close to 0V, and then the first switch QA1 is controlled to be turned on at the same time, realizing the soft switching effect. By controlling the first switch QA1 and the second switch QB1 to repeatedly switch on and off, the process of transferring the electric quantity of the electric core B1 between the magnetic core and other batteries can be realized. If the QA synchronous switch and the QB synchronous switch of other winding units on the magnetic ring are controlled to be turned on and off alternately, the process of transferring the electric quantity between different battery monomers can be realized, so as to realize voltage balancing. Figure 2

[0060] In addition, the first switch or the second switch to be turned on is realized to achieve soft switching effect, so as to reduce switching loss and help to improve switching frequency.

[0061] It is worth mentioning that the first time, the second time, the third time and the fourth time can be reasonably set according to actual needs, and are not limited here. The first time, the second time, the third time and the fourth time can be executed cyclically.

[0062] ​In some embodiments, the controller can further be configured to acquire the voltage of each battery cell, determine the battery cell to be balanced according to the voltage of each battery cell, and perform a corresponding control strategy for voltage balancing. For example, the plurality of battery cells include a first battery cell and a second battery cell, and the voltage of the first battery cell is higher than the voltage of the second battery cell. The controller can further be configured to control the first switch tube connected to the first battery cell to be turned on for a first on-time, and control the first switch tube connected to the second battery cell to be turned on for a second on-time. The current of the first battery to be balanced flows into the corresponding winding through the first switch tube, and all the windings on the toroidal magnetic core induce corresponding induced voltages. The winding corresponding to the second battery cell charges the second battery cell through the first switch tube connected to the second battery cell, and the toroidal magnetic core operates in the first quadrant. The second on-time is at least one time point within the first on-time, i.e., the first switch tube corresponding to the first battery cell can be turned on at the same time as the first switch tube corresponding to the second battery cell, or the first switch tube corresponding to the second battery cell is turned on after the first switch tube corresponding to the first battery cell is turned on.

[0063] Further, the controller can further be configured to control each first switch tube to be turned off and each second switch tube to be turned off for a dead-time after the first on-time ends. The freewheeling current generated by each winding is discharged back to the corresponding battery cell through the second switch tube connected thereto. Alternatively, the voltage across the second switch tube is less than a predetermined value (e.g., close to zero), so that the second switch tube is turned on at zero voltage.

[0064] Further, the controller can further be configured to control the second switch tube connected to the first battery cell to be turned on for a third on-time after the dead-time ends, and control the second switch tube connected to the second battery cell to be turned on for a fourth on-time. The current of the first battery to be balanced flows into the corresponding winding through the second switch tube, and all the windings on the toroidal magnetic core induce corresponding induced voltages. The winding corresponding to the second battery cell charges the second battery cell through the second switch tube connected to the second battery cell, and the toroidal magnetic core operates in the third quadrant.

[0065] The balancing circuit of the present application can selectively balance the battery cells that need to be balanced, and synchronously transfer the unbalanced battery cell to the balancing through the winding of the toroidal transformer. The magnetic core of the present application can operate in the first quadrant and the third quadrant, so that the utilization rate of the magnetic core is higher.

[0066] In a specific example, the first battery cell is battery cell B1, and the second battery cell is battery cell B3. The voltage of battery cell B1 needs to be transferred to battery cell B3. The controller outputs a control driving signal to the corresponding switch tube with a reference voltage of 0V Figure 4Wherein, QA1_G is the drive of the first switch tube QA1, QB1_G is the drive of the second switch tube QB1, QA3_G is the drive of the first switch tube QA3, and QB3_G is the drive of the second switch tube QB3. The QA_G and QB_G drive signals are provided with a dead time DT in time sequence, the QA_G and QB_G turn-on and turn-off time are the same, and the phases are 180° apart.

[0067] Wherein, t_on is the turn-on time, and t_off is the turn-off time

[0068] Then the system working frequency is:

[0069]

[0070] Since the ring-shaped magnetic core adopts ferrite or other types of high-frequency magnetic cores, the switching frequency is related to the material. Too low frequency may cause the magnetic core to be saturated, and the efficiency to be reduced. Too high frequency may increase the switching loss or cause EMC interference problems. Therefore, the working frequency of the synchronous switch (i.e. each switch tube) can be controlled at 50kHZ-500kHZ, and the specific value needs to be calculated according to the magnetic ring parameters.

[0071] The process of transferring the electric quantity of the battery B1 to the battery B3 is as follows Figure 3As shown, first, as shown in "State A'," the controller simultaneously controls the first switch QA1 and the first switch QA3 to conduct during the first on-time, while the second switch QB1 and the first switch QB3 are off, and the winding T1 circuit is conducting. The current in cell B1 flows through winding T1, and the other windings on the same core also sense a corresponding electromotive force. Since the first switch QA3 is on, the induced voltage preferentially charges cell B3 through the first switch QA3, and the toroidal transformer (i.e., the structure consisting of the magnetic core and the windings disposed thereon) operates in the first quadrant. After the first on-time expires, the first switch QA1 and the first switch QA3 are simultaneously turned off, as shown in "State B'," entering the dead time. The stored current generated by the windings on the magnetic core flows through the body diodes of the second switches and is then fed back to the corresponding cells, or the voltage across the second switches approaches 0V. Simultaneously, second switches QB1 and QB3 are controlled to conduct, as shown in "State C'." This achieves zero-crossing conduction of second switch QB, connecting the loops of windings T0 and T2. The other windings on the same core also experience a corresponding electromotive force. However, since second switch QB3 is on, the induced voltage preferentially charges battery cell B3 through second switch QB3, placing the toroidal transformer in the third quadrant. After a period of time, second switches QB1 and QB3 are controlled to shut off. As shown in "State D'," when the dead time re-enters, the stored current generated by the windings on the core flows back to the battery through the body diode of the first switch, or the voltage across the first switch approaches 0V, achieving zero-crossing conduction of the first switch. Simultaneously, first switches QA1 and QA3 are controlled to conduct, returning to "State A'." This process is repeated during system operation. QA1 and QA3 are turned on or off synchronously, QB1 and QB3 are turned on or off synchronously, and the first switch tube QA and the second switch tube QB are turned on alternately to transfer electricity from battery cell B1 to battery cell B3, thereby making the voltage more balanced.

[0072] Similarly, if Figure 1 As shown in the toroidal transformer on the right, the balancing circuit can include n+1 minimum balancing units. By controlling the switching transistors QAn and QBn corresponding to each cell to be balanced in the entire circuit system to alternately turn on and off in phase, the power of the high-voltage cell can be transferred to the low-voltage cell through the magnetic core. It is also important to note that the frequency of the in-phase switching can be controlled to accommodate different core sizes, preventing increased saturation losses in the magnetic ring.

[0073] The phases of the first switching tubes of each battery cell involved in balancing are the same, and the phases of the second switching tubes are the same. For example, the battery cells involved in balancing include a first battery cell to be balanced and a second battery cell to be balanced. Then the phases of the first switching tubes are the same, which means that the first switching tube corresponding to the first battery cell to be balanced and the first switching tube corresponding to the second battery cell to be balanced are turned on or off at the same time. Similarly, the phases of the second switching tubes are the same, which means that the second switching tube corresponding to the first battery cell to be balanced and the second switching tube corresponding to the second battery cell to be balanced are turned on or off at the same time. By alternating the conduction of the first switching tube and the second switching tube, and reserving a dead time DT between the conduction of each switching tube, the first switching tube and the second switching tube are both turned off during the dead time DT. By adjusting the duty ratio of the drive signals QAn_G and QBn_G at the same time, the magnitude of the balancing current of each battery cell can be controlled separately. Figure 5 As shown, if the first and second switches QA1, QB1 connected to the discharge-controlling battery cell B1 have the same duty cycle and a 180° phase difference, and the first and second switches QA3, QB3 connected to the rechargeable battery B3 have the same duty cycle and a turn-on delay TB (i.e., first switch QA3 turns on only after first switch QA1 has been on for time TB), and the turn-off time is ahead of TF (i.e., after first switch QA3 turns off, first switch QA1 remains on for TB before turning off), then the balancing (charge and discharge) current of battery cell B1 is controlled. Similarly, the first switch QAn and the first switch QBn of each battery cell turn on and off simultaneously, with a 180° phase difference, and the duty cycles of the first and second switches QAn, QBn of each cell can be independently controlled. This allows for arbitrary transfer of battery pack charge, and the balancing (charge and discharge) current can be independently controlled. For voltage differences with large balancing currents, the corresponding switch can be turned on for a longer time. For voltage differences with small balancing currents, the corresponding switch can be turned on for a shorter time. This allows the entire balancing battery pack to quickly reach a balanced state, achieving rapid voltage balancing for the series battery pack. By controlling the duty cycle of turning on and off balancing cells with the same conduction phase, the balancing current can be controlled to prevent excessive current from damaging the battery.

[0074] In another embodiment of the present application, an equalization circuit is further provided, which is different from the above embodiments. Figure 6As shown, the balancing circuit in the embodiment also includes a charging winding T IN, which is wound on the closed magnetic core T101 along the circumferential direction of the closed magnetic core T101, for example, uniformly distributed on the entire closed magnetic core, wherein the two ends of the charging winding T IN are adapted to be connected to a power supply for charging at least one of the plurality of battery cells, so as to balance the charge of each battery cell. For example, the battery includes a first battery cell and a second battery cell connected in series, and the switch tube assembly is also used to transfer the charge provided by the charging winding to the first battery cell and / or the second battery cell, so as to balance the charge of the first battery cell and the second battery cell.

[0075] Alternatively, the input end of the charging winding T IN can also be connected to a full-bridge circuit, which can include four switch tubes, wherein two symmetrical switch tubes control the current direction between the positive and negative poles of the power supply, and the other two switch tubes are connected in parallel with the two switch tubes, respectively, to realize the reverse flow of current. When the working state of the switch tube changes, the voltage and current on the connected charging winding T IN also change accordingly.

[0076] For example, according to the voltages of the first battery cell and the second battery cell, the battery cell that needs to be charged can be determined. For example, taking battery cell B1 and battery cell B2 as an example, when the voltage of battery cell B1 is higher than that of battery cell B2, that is, the charge of battery cell B1 is higher than that of battery cell B2, when the charging winding T IN is connected to the driving signal through the connected full-bridge circuit, the current provided by the full-bridge circuit flows through the charging winding T IN. The controller can control the first switch tube QA2 connected to the battery cell B2 to be conductive, and the other windings of the magnetic ring will also induce corresponding electromotive force. Since the first switch tube QA2 is in the conductive state, the induced voltage preferentially charges the battery cell B2 through the first switch tube QA2, thereby transferring the charge provided to the charging winding T IN to the battery cell B2, increasing the charge of the battery cell B2, balancing the charge of the battery cell B1, and improving the consistency of the battery, avoiding the problem of declining vehicle endurance due to poor consistency, improving the service life of the battery, improving the endurance and safety of the battery, and improving driving safety.

[0077] Specifically, some details of the balancing circuit can refer to the description in the foregoing description, which will not be described here.

[0078] In still another embodiment of the present application, an equalization circuit is also provided, which, compared with the foregoing embodiments, further comprises a plurality of freewheeling inductors, each winding is connected to a corresponding battery cell through one of the freewheeling inductors, and each winding is connected to the first battery cell and the second battery cell through at least one of the freewheeling inductors. Further, a first end of at least one of the freewheeling inductors is connected to a first potential end of the winding, and a second end of the at least one of the freewheeling inductors is connected to a positive electrode of the first battery cell and a negative electrode of the second battery cell; and / or a first end of at least one of the freewheeling inductors is connected to a second potential end of the winding, and a second end of the at least one of the freewheeling inductors is connected to a negative electrode of the first battery cell and a positive electrode of the second battery cell. For example, as shown in FIG. 8, a first potential end of the winding T0 is connected to one end of the freewheeling inductor LS0, the other end of the freewheeling inductor LS0 is connected to a negative electrode of the battery cell B1, a first potential end of the winding T1 is connected to one end of the freewheeling inductor LS1, and the other end of the freewheeling inductor LS1 is connected to a negative electrode of the battery cell B2 and a positive electrode of the battery cell B1. Similarly, other windings and corresponding freewheeling inductors are connected to corresponding battery cells in the same manner. Figure 7

[0079] By adding the freewheeling inductors, the equalization current can be buffered, the equalization current is smoother, and the switching loss is reduced.

[0080] According to another aspect of the present application, a vehicle is also provided, which comprises a power battery and an equalization circuit. The equalization circuit can be implemented as the equalization circuit described above, and reference can be made to the description above, which will not be repeated here.

[0081] In summary, according to the equalization circuit and the vehicle according to the embodiments of the present application, the closed magnetic core and the plurality of windings arranged on the closed magnetic core are used as a medium for electric quantity transmission, the closed magnetic core has the characteristics of magnetic circuit closure and small magnetic leakage, the transformer made by using these characteristics has the characteristics of small leakage inductance, good synchronization, high work efficiency, etc. In the entire equalization circuit, the conduction or turn-off of the first switch tube and the second switch tube corresponding to each winding is synchronously controlled, and the battery cell units that need to be equalized are selectively equalized, the unbalanced electric quantity of the series-connected battery cells is synchronously transmitted to the equalization through the windings on the closed magnetic core, the battery cells are equalized, the consistency is better, the problem of degradation of the vehicle endurance caused by poor consistency is avoided, the service life of the battery is improved, the endurance and safety of the battery are improved, and the driving safety is improved.

[0082] Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are merely exemplary and are not intended to limit the scope of the present application. Those of ordinary skill in the art can make various changes and modifications without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0083] ​Similarly, it is to be understood that the embodiments of the present application can be used in the exact opposite way of that described in the examples, and that the present application should not be construed as limited to only one or the other of the embodiments described in the examples. Similarly, it is to be understood that, for the avoidance of doubt, the

[0084] Further, those skilled in the art will appreciate that the features of the various embodiments described herein are not mutually exclusive, but can be combined in different ways depending upon the needs and resources available. Thus, the application is not to be construed as limited to the specific embodiments disclosed in the examples, but only by the claims. Furthermore, the claimed application is intended to cover adjunct claims that are the equivalent of the claims presented in this application.

[0085] It is noted that the foregoing examples have been provided merely for the purposes of illustration and are not intended to limit the application as claimed. Other examples of variations that may fall within the scope of the application are possible. For example, any aspect of the claimed application can be applied in any combination with any other aspect of the claimed application. Furthermore, any features of the application can take any form of combinations with any other features of the application. For example, in the claims, any of the claimed application can be used in any combination.

Claims

1. An equalizing circuit, characterized in that: include: Closed core; a winding, the winding being wound around the closed magnetic core, the winding being adapted to simultaneously connect the first battery core and the second battery core connected in series, and having a polarity direction opposite to that of the first battery core and the second battery core; a switch tube assembly, the switch tube assembly being disposed between the winding and the first battery core, and between the winding and the second battery core, and being used to control the mutual transfer of power between the first battery core and the second battery core; The switch tube assembly includes a first switch tube and a second switch tube, the first switch tube is arranged between the winding and the first battery core, and the second switch tube is arranged between the winding and the second battery core; The first switch tube and the second switch tube are configured to be alternately turned on and off, so that when the first switch tube is turned on and the second switch tube is turned off, the power of the first battery cell can be transferred to the second battery cell; When the second switch tube is turned on and the first switch tube is turned off, the power of the second battery cell can be transferred to the first battery cell; When the first switching tube connected to the first battery cell is turned on, and the second switching tube connected to the first battery cell, the first switching tube connected to the second battery cell, and the second switching tube connected to the second battery cell are all turned off, the power of the first battery cell is transferred to the second battery cell via the first switching tube connected to the second battery cell; When the first switching tube connected to the first battery cell, the second switching tube connected to the first battery cell, the first switching tube connected to the second battery cell, and the second switching tube connected to the second battery cell are all turned off, the freewheeling current of the winding is reversely charged back to the first battery cell through the second switching tube connected to the first battery cell; When the second switching tube connected to the first battery cell is turned on, and the first switching tube connected to the first battery cell, the first switching tube connected to the second battery cell, and the second switching tube connected to the second battery cell are turned off, the electricity of the first battery cell is transferred to the second battery cell through the second switching tube connected to the second battery cell.

2. The equalizing circuit according to claim 1, wherein: The first potential end of the winding is connected to the positive electrode of the first battery cell and the negative electrode of the second battery cell, and the second potential end of the winding is connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell.

3. The equalizing circuit according to claim 1, wherein: The first end of the first switch tube is connected to the second potential end of the winding, the second end of the first switch tube is connected to the negative electrode of the first battery cell, and the first switch tube further includes a control end, and the control end of the first switch tube is suitable for connecting to a controller; The first end of the second switch tube is connected to the second potential end of the winding, the second end of the second switch tube is connected to the positive electrode of the second battery cell, and the second switch tube also includes a control end, and the control end of the second switch tube is suitable for connecting to a controller.

4. The equalizing circuit according to claim 1, wherein: The first switching tube is equivalent to a first switching element and a first diode connected in parallel, and the second switching tube is equivalent to a second switching element and a second diode connected in parallel.

5. The equalizing circuit according to any one of claims 1 to 4, characterized in that: The balancing circuit includes a plurality of windings and a plurality of switch tube assemblies, and each winding has the same number of turns.

6. The equalizing circuit according to claim 5, wherein: Any two of the plurality of windings are suitable for connecting to the same battery cell in series, and the polarities of the connections between any two of the windings and the same battery cell are opposite.

7. The equalizing circuit according to any one of claims 1 to 4, characterized in that: The balancing circuit further includes a charging winding, which is wound around the closed magnetic core along the circumference of the closed magnetic core, and two ends of the charging winding are suitable for connecting to a power source; The switch tube assembly is further used to control the power provided by the charging winding to be transferred to the first battery cell and / or the second battery cell, so that the power of the first battery cell and the power of the second battery cell are balanced.

8. The equalizing circuit according to any one of claims 1 to 4, wherein: It also includes multiple freewheeling inductors, and the winding is connected to the first battery core and the second battery core through at least one of the freewheeling inductors.

9. The equalizing circuit according to claim 8, wherein: The first end of the at least one freewheeling inductor is connected to the first potential end of the winding, and the second end of the at least one freewheeling inductor is connected to the positive pole of the first battery cell and the negative pole of the second battery cell; and / or the first end of the at least one freewheeling inductor is connected to the second potential end of the winding, and the second end of the at least one freewheeling inductor is connected to the negative pole of the first battery cell and the positive pole of the second battery cell.

10. A vehicle, characterized in that: The device comprises a battery and the balancing circuit according to any one of claims 1 to 9, wherein the battery is connected to the balancing circuit.

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