Battery management system, battery device and electric device

Abstract

The utility model discloses a battery management system, a battery device and a power utilization device. The battery management system comprises a switch group, a second switch, a third switch and a bidirectional transformer; the switch group is electrically connected with each single battery in the battery pack, and the switch group comprises a plurality of first switches; the bidirectional transformer comprises a first winding, a second winding and a third winding, the first winding is respectively coupled with the second winding and the third winding, the first winding is electrically connected with each single battery in the battery pack through the switch group, and the second winding is electrically connected with each even-numbered single battery in the battery pack through the second switch and the switch group; and the third winding is electrically connected with each odd number of single batteries in the battery pack through the third switch and the switch group. According to the embodiment of the invention, the problems of complex topology and high cost of the active equalization circuit in the related technology can be solved.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to a battery management system, battery device, and power consumption device. Background Technology

[0002] With the rapid development of electric vehicles and energy storage systems, lithium-ion battery packs are widely used due to their advantages such as high energy density and long cycle life. However, due to differences in manufacturing processes, operating temperatures, and aging levels, individual cells within a battery pack are prone to the "weakest link effect," where the state of charge (SOC) and capacity are inconsistent. This leads to a decrease in the system's usable capacity, a shortened lifespan, and even the risk of thermal runaway. To improve the energy utilization rate of battery packs and extend their cycle life, effective battery balancing technologies must be employed to reduce the inconsistency within the battery pack.

[0003] Depending on the balancing method, balancing circuits in related technologies can be divided into passive balancing and active balancing technologies. Passive balancing technology achieves voltage balance by dissipating energy through resistors, but suffers from low efficiency and increased thermal management burden. Active balancing technology can effectively utilize the full charge and capacity of the battery pack, offering high overall efficiency and strong balancing capabilities, and represents the main development direction for future energy balancing technologies. However, active balancing circuits in related technologies suffer from complex topologies and high costs. Utility Model Content

[0004] This application provides a battery management system, a battery device, and an electrical device, which can solve the problems of complex topology and high cost of active balancing circuits in related technologies.

[0005] In a first aspect, this application provides a battery management system, including a switch group, a second switch, a third switch, and a bidirectional transformer; the switch group is electrically connected to each individual battery cell in the battery pack, and the switch group includes a plurality of first switches; the bidirectional transformer includes a first winding, a second winding, and a third winding, the first winding being coupled to the second winding and the third winding respectively, the first winding being electrically connected to each individual battery cell in the battery pack through the switch group, the second winding being electrically connected to each even-numbered individual battery cell in the battery pack through the second switch and the switch group, and the third winding being electrically connected to each odd-numbered individual battery cell in the battery pack through the third switch and the switch group.

[0006] According to the battery management system provided in this application embodiment, its bidirectional transformer includes three windings. The first winding is electrically connected to each individual cell in the battery pack through a switch group. The second winding is electrically connected to each even-numbered individual cell in the battery pack through a switch group and a second switch. The third winding is electrically connected to each odd-numbered individual cell in the battery pack through a switch group and a third switch. For any individual cell, when the first switch between it and the first winding is turned on, energy can be transferred between the individual cell and the first winding. For any even-numbered individual cell, when the first and second switches between it and the second winding are turned on, energy can be transferred between the individual cell and the second winding. For any odd-numbered individual cell, when the first and third switches between it and the third winding are turned on, energy can be transferred between the individual cell and the third winding. In this way, only one bidirectional transformer is needed, and energy balance between any two individual cells can be achieved by controlling the state of the switches. This solves the problems of complex topology and high cost of active balancing circuits in related technologies. Furthermore, it is easy to expand and can be applied to battery packs with any total number of individual cells.

[0007] In one possible implementation of the first aspect, the number of first switches in the switch group is one more than the number of individual cells in the battery pack; the positive terminal of each odd-numbered individual cell in the battery pack is electrically connected to a first connecting line via a first switch; the positive terminal of each even-numbered individual cell in the battery pack is electrically connected to a second connecting line via a first switch; one end of a first winding is electrically connected to the first connecting line, and the other end of the first winding is electrically connected to the second connecting line; one end of a second winding is electrically connected to the first connecting line, and the other end of the second winding is electrically connected to the second connecting line; one end of a third winding is electrically connected to the first connecting line, and the other end of the third winding is electrically connected to the second connecting line; and at least one of the first connecting line and the second connecting line is electrically connected to the second winding via a second switch, and at least one of the first connecting line and the second connecting line is electrically connected to the third winding via a third switch.

[0008] In this embodiment, the number of first switches is one more than the total number of individual cells in the battery pack. A first connecting line is provided to electrically connect the positive terminal of each odd-numbered individual cell in the battery pack, and a second connecting line is provided to electrically connect the positive terminal of each even-numbered individual cell. The first and second connecting lines are electrically connected to the two ends of the first winding, the two ends of the second winding, and the two ends of the third winding, respectively. In this way, the first winding can be electrically connected to any individual cell, the second winding to any even-numbered individual cell, and the third winding to any odd-numbered individual cell with a smaller number of switches, which can further simplify the topology and reduce costs.

[0009] In one possible implementation of the first aspect, when the total number of individual cells in the battery pack is even, the negative terminal of the last individual cell in the battery pack is electrically connected to the first connecting line.

[0010] In this embodiment, by electrically connecting the negative terminal of the last even-numbered cell in the battery pack to the first connection line, it is not necessary to set up an additional connection line, which can further simplify the circuit topology.

[0011] In one possible implementation of the first aspect, when the total number of individual cells in the battery pack is odd, the negative terminal of the last individual cell in the battery pack is electrically connected to the second connecting line.

[0012] In this embodiment, by electrically connecting the negative terminal of the last odd-numbered cell in the battery pack to the second connection line, it is not necessary to set up an additional connection line, which can further simplify the circuit topology.

[0013] In one possible implementation of the first aspect, the battery management system further includes a fourth switch, wherein at least one end of the first winding is electrically connected to the switch group via the fourth switch.

[0014] In this embodiment, by setting a fourth switch, it is equivalent to designing a double safety measure, which can improve the reliability of the circuit.

[0015] In one possible implementation of the first aspect, at least one of the first switch, the second switch, the third switch, and the fourth switch includes a bidirectional switching transistor.

[0016] In this embodiment, since bidirectional MOSFETs have advantages over relay switches in terms of speed, lifespan, reliability, lack of physical contacts, absence of mechanical wear and arc erosion, and bidirectional conduction control capability, when the switch includes a bidirectional switching transistor, it is possible to more accurately control the charging or discharging of individual batteries, thereby improving circuit reliability.

[0017] In one possible implementation of the first aspect, the battery management system is configured to:

[0018] If the absolute value of the difference between the voltage of the i-th cell and the voltage of the j-th cell in the battery pack is greater than a preset threshold, and the j-th cell is an even-numbered cell in the battery pack, then the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the second switch is turned on.

[0019] In this embodiment, the i-th cell can be any single cell, the j-th cell can be any even-numbered cell, the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the second switch is turned on. In this way, energy balance can be achieved between any single cell and any even-numbered cell.

[0020] In one possible implementation of the first aspect, the battery management system is configured to:

[0021] If the absolute value of the difference between the voltage of the i-th cell and the voltage of the j-th cell in the battery pack is greater than a preset threshold, and the j-th cell is an odd-numbered cell in the battery pack, then the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the third switch is turned on.

[0022] In this embodiment, the i-th cell can be any single cell, the j-th cell can be any odd-numbered single cell, the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the third switch is turned on. In this way, energy balance can be achieved between any single cell and any odd-numbered single cell.

[0023] In one possible implementation of the first aspect, the i-th cell and the j-th cell are the two cells with the highest and lowest voltages in the battery pack.

[0024] In this embodiment, when the voltage difference between the single cell with the highest voltage and the single cell with the lowest voltage in the battery pack is greater than a preset threshold, equalization control is initiated, resulting in a high equalization speed.

[0025] Based on the same technical concept, in a second aspect, embodiments of this application provide a battery device including a battery management system as described in any embodiment of the first aspect.

[0026] Based on the same technical concept, in a third aspect, embodiments of this application provide an electrical device, including a battery device as described in any embodiment of the first aspect.

[0027] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0028] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the structure of a battery management system according to an embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the structure of a battery management system according to another embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the structure of a battery management system according to another embodiment of this application;

[0032] Figure 4 This is a schematic diagram of the charging and discharging of a single battery cell according to an embodiment of this application;

[0033] Figure 5 This is a schematic diagram of the working mode of a battery management system according to an embodiment of this application;

[0034] Figure 6 This is a schematic diagram of the working mode of a battery management system according to another embodiment of this application;

[0035] Figure 7 This is a schematic diagram of the working mode of a battery management system according to another embodiment of this application;

[0036] Figure 8 This is a schematic diagram of the structure of a battery device according to an embodiment of this application. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0039] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0040] The equalization circuit can adjust the voltage or charge state of each individual cell in the battery pack, eliminate their differences, prevent overcharging / over-discharging, thereby improving the overall performance of the battery pack and extending its service life.

[0041] For example, in an active balancing circuit, a transformer can be used to transfer energy between individual cells for balancing. However, related technologies require a transformer for each individual cell, resulting in complex circuit topologies, high costs, and difficulties in large-scale application.

[0042] To address the aforementioned technical problems, embodiments of this application provide a battery management system, a battery device, and an electrical device. The embodiments of this application will be described below with reference to the accompanying drawings.

[0043] The battery management system provided in the embodiments of this application will be described below.

[0044] like Figure 1 As shown, the battery management system includes a switch group 10, a second switch 2, a third switch 3, and a bidirectional transformer 5.

[0045] The battery management system is used to manage the battery pack 200. The battery pack 200 includes, but is not limited to, battery packs in electrical devices and battery packs in energy storage systems.

[0046] Battery pack 200 comprises multiple individual cells connected in series. For example, battery pack 200 comprises n individual cells connected in series, where n is an integer greater than 1. Specifically, the first individual cell B1 to the nth individual cell B1... n The cells are connected in series, with the negative terminal of the first cell B1 electrically connected to the positive terminal of the second cell B2, the negative terminal of the second cell B2 electrically connected to the positive terminal of the third cell B3, and so on, until the (n-1)th cell B... n-1 The negative electrode and the nth single cell B n The positive terminal of the first single cell B1 is connected; the positive terminal of the first single cell B1 serves as the positive terminal of the battery pack 200, and the positive terminal of the nth single cell B... n The negative electrode is used as the negative electrode of battery pack 200.

[0047] The switch group 10 is electrically connected to each individual battery cell in the battery pack 200. The switch group 10 includes multiple first switches 1. Each individual battery cell has a first switch 1 connected to its positive and negative terminals. The bidirectional transformer 5 is electrically connected to each individual battery cell through the first switches 1. By controlling the state of the first switch 1 connected to the corresponding individual battery cell, it is possible to control whether the individual battery cell can connect to the bidirectional transformer 5, thereby controlling whether the individual battery cell can transfer energy through the bidirectional transformer 5, and thus achieving corresponding equalization control.

[0048] The bidirectional transformer 5 includes a first winding W1, a second winding W2, and a third winding W3. The first winding W1 is coupled to both the second winding W2 and the third winding W3. The first winding W1 is the primary winding, and the second winding W2 and the third winding W3 are the two secondary windings. Energy can be transferred between the first winding W1 and the second winding W2, and also between the first winding W1 and the third winding W3.

[0049] For example, the second winding W2 and the third winding W3 have the same winding direction.

[0050] For example, the number of turns in the first winding W1, the second winding W2, and the third winding W3 can be the same. Of course, the number of turns in the first winding W1, the second winding W2, and the third winding W3 can also be designed according to actual needs.

[0051] The first winding W1 is electrically connected to each individual cell in the battery pack 200 through the switch group 10. The second winding W2 is electrically connected to each even-numbered individual cell in the battery pack 200 through the second switch 2 and the switch group 10. The third winding W3 is electrically connected to each odd-numbered individual cell in the battery pack 200 through the third switch 3 and the switch group 10.

[0052] Understandably, the first winding W1 is electrically connected to the positive and negative terminals of each individual cell in the battery pack 200, the second winding W2 is electrically connected to the positive and negative terminals of each even-numbered individual cell in the battery pack 200, and the third winding W3 is electrically connected to the positive and negative terminals of each odd-numbered individual cell in the battery pack 200; and the first winding W1 is electrically connected to any individual cell via the first switch 1, the second winding W2 is electrically connected to any even-numbered individual cell via the first switch 1 and the second switch 2, and the third winding W3 is electrically connected to any odd-numbered individual cell via the first switch 1 and the third switch 3.

[0053] When the first switch 1 between any individual battery cell and the first winding W1 is turned on, the individual battery cell is connected to the first winding W1, and energy can be transferred between the individual battery cell and the first winding W1.

[0054] For any even-numbered cell, when the first switch 1 and the second switch 2 between the cell and the second winding W2 are turned on, the cell is connected to the second winding W2, and energy can be transferred between the cell and the second winding W2.

[0055] For any odd-numbered individual battery cell, when the first switch 1 and the third switch 3 between the individual battery cell and the third winding W3 are turned on, the individual battery cell is connected to the third winding W3, and energy can be transferred between the individual battery cell and the third winding W3.

[0056] As an example, in the case where it is necessary to balance the i-th cell and the j-th cell in the battery pack, where the i-th cell can be any cell and the j-th cell is an even-numbered cell, the first switch connected to the i-th cell can be turned on, the first switch connected to the j-th cell can be turned on, and the second switch can be turned on. In this way, the first winding W1 and the second winding W2 form a flyback converter to realize the energy transfer between the i-th cell and the j-th cell, so as to achieve the balanced control of the i-th cell and the j-th cell.

[0057] As another example, when it is necessary to balance the i-th cell and the j-th cell in the battery pack, where the i-th cell can be any cell and the j-th cell is an odd-numbered cell, the first switch connected to the i-th cell can be turned on, the first switch connected to the j-th cell can be turned on, and the third switch can be turned on. In this way, the first winding W1 and the third winding W3 form a flyback converter to realize the energy transfer between the i-th cell and the j-th cell, so as to achieve the balanced control of the i-th cell and the j-th cell.

[0058] The bidirectional transformer 5 enables bidirectional energy transfer. For example, if the energy of the i-th cell is higher than that of the j-th cell, the i-th cell releases energy to the bidirectional transformer 5, and the j-th cell absorbs energy from the bidirectional transformer 5. Conversely, if the energy of the i-th cell is lower than that of the j-th cell, the j-th cell releases energy to the bidirectional transformer 5, and the i-th cell absorbs energy from the bidirectional transformer 5.

[0059] The i-th and j-th individual cells are two different individual cells. The i-th individual cell can be any single cell, and the j-th individual cell can be any odd-numbered cell, or any even-numbered cell. Furthermore, the total number of individual cells in the battery pack can be even or odd. In other words, the embodiments of this application can achieve energy balance between any two individual cells.

[0060] According to the battery management system provided in the embodiments of this application, its bidirectional transformer 5 includes three windings. The first winding W1 is electrically connected to each individual cell in the battery pack 200 through a switch group 10. The second winding W2 is electrically connected to each even-numbered individual cell in the battery pack 200 through a switch group 10 and a second switch 2. The third winding W3 is electrically connected to each odd-numbered individual cell in the battery pack 200 through a switch group 10 and a third switch 3. For any individual cell, when the first switch 1 between it and the first winding W1 is turned on, energy can be transferred between the individual cell and the first winding W1. For any even-numbered individual cell... When the first switch 1 and the second switch 2 between the cell and the second winding W2 are turned on, energy can be transferred between the cell and the second winding W2. For any odd-numbered cell, when the first switch 1 and the third switch 3 between the cell and the third winding W3 are turned on, energy can be transferred between the cell and the third winding W3. In this way, only a bidirectional transformer is needed, and energy balance between any two cells can be achieved by controlling the state of the switches. This solves the problems of complex topology and high cost of active balancing circuits in related technologies. Furthermore, it is easy to expand and can be applied to battery packs with any total number of cells.

[0061] In some embodiments, such as Figure 1 As shown, the number of first switches 1 in switch group 10 is one more than the number of individual cells in battery pack 200. For example, battery pack 200 includes n individual cells connected in series, labeled as the first individual cell B1 to the nth individual cell B1. n The switch group 10 includes n+1 first switches 1. For any two adjacent connected individual cells, the negative terminal of the previous individual cell and the positive terminal of the next individual cell are electrically connected to the same first switch 1. For example, the negative terminal of the first individual cell B1 and the positive terminal of the second individual cell B2 are electrically connected to the same first switch 1, the negative terminal of the second individual cell B2 and the positive terminal of the third individual cell B3 are electrically connected to the same first switch 1, and so on, the negative terminal of the (n-1)th individual cell B2 and the positive terminal of the nth individual cell B3 are electrically connected to the same first switch 1. n The positive terminal is connected to the same first switch 1.

[0062] The positive terminal of each odd-numbered cell in the battery pack 200 is electrically connected to the first connecting line 61 via the first switch 1; the positive terminal of each even-numbered cell in the battery pack 200 is electrically connected to the second connecting line 62 via the first switch 1.

[0063] The first connecting wire 61 and the second connecting wire 62 are electrically connected to the two ends of the first winding W1, the two ends of the second winding W2, and the two ends of the third winding W3, respectively. In other words, one end of the first winding W1 is electrically connected to the first connecting wire 61, and the other end of the first winding W1 is electrically connected to the second connecting wire 62; one end of the second winding W2 is electrically connected to the first connecting wire 61, and the other end of the second winding W2 is electrically connected to the second connecting wire 62; one end of the third winding W3 is electrically connected to the first connecting wire 61, and the other end of the third winding W3 is electrically connected to the second connecting wire 62.

[0064] In addition, at least one of the first connecting line 61 and the second connecting line 62 is electrically connected to the second winding W2 via the second switch 2, and at least one of the first connecting line 61 and the second connecting line 62 is electrically connected to the third winding W3 via the third switch 3.

[0065] As an example, such as Figure 1 As shown, the same-name terminal of the first winding W1 is electrically connected to the first connecting line 61, and the opposite-name terminal of the first winding W1 is electrically connected to the second connecting line 62. The opposite-name terminal of the second winding W2 is electrically connected to the first connecting line 61, and the same-name terminal of the second winding W2 is electrically connected to the second connecting line 62. The same-name terminal of the third winding W3 is electrically connected to the first connecting line 61, and the opposite-name terminal of the third winding W3 is electrically connected to the second connecting line 62. The second connecting line 62 and the opposite-name terminal of the second winding W2 are electrically connected through the second switch 2, and the second connecting line 62 and the same-name terminal of the third winding W3 are electrically connected through the third switch 3.

[0066] Of course, in other embodiments, it can also be designed such that: the first connecting line 61 and the second winding W2 are electrically connected through the second switch 2, or the first connecting line 61, the second connecting line 62, and the second winding W2 are all electrically connected through the second switch 2. The first connecting line 61 and the third winding W3 are electrically connected through the second switch 2, or the first connecting line 61, the second connecting line 62, and the third winding W3 are all electrically connected through the second switch 2.

[0067] In this embodiment, the number of first switches 1 is one more than the total number of individual cells in the battery pack 200. A first connecting line 61 is provided to electrically connect to the positive terminal of each odd-numbered individual cell in the battery pack 200, and a second connecting line 62 is provided to electrically connect to the positive terminal of each even-numbered individual cell. The first connecting line 61 and the second connecting line 62 are respectively electrically connected to the two ends of the first winding W1, the two ends of the second winding W2, and the two ends of the third winding W3. In this way, the first winding W1 can be electrically connected to any individual cell, the second winding W2 can be electrically connected to any even-numbered individual cell, and the third winding W3 can be electrically connected to any odd-numbered individual cell with a smaller number of switches, which can further simplify the topology and reduce costs.

[0068] In some embodiments, such as Figure 1 or Figure 2 As shown, the total number of individual cells in the battery pack is n, where n is an even number. The last individual cell in the battery pack of 200 is B. n The negative terminal is electrically connected to the first connecting line 61. Thus, the last even-numbered cell B... n The positive terminal is electrically connected to one end (such as the opposite terminal) of the second winding W2 via the second connecting wire 62, and the last even-numbered single cell B n The negative terminal is electrically connected to the other end (same-name terminal) of the second winding W2 via the first connecting wire 61, when it is necessary to connect the last even-numbered cell B. n In the case of balancing, the corresponding switch can be closed so that the second winding W2 can participate in the balancing adjustment.

[0069] Understandably, the first connecting line 61 is not only electrically connected to the positive terminal of each odd-numbered cell, but also electrically connected to the negative terminal of each even-numbered cell.

[0070] Of course, in other embodiments, an additional connecting line can also be provided to connect the last even-numbered cell B. n The negative terminal is electrically connected to the other end of the second winding W2. In this embodiment, the last even-numbered cell B in the battery pack 200 is connected... n The negative terminal is electrically connected to the first connection line 61, eliminating the need for additional connection lines and further simplifying the circuit topology.

[0071] In other embodiments, such as Figure 3 As shown, the total number of individual cells in the battery pack is m, where m is an odd number. The last individual cell in the 200-cell battery pack is B. m The negative terminal is electrically connected to the second connecting wire 62. Thus, the last odd-numbered cell B... mThe positive terminal is electrically connected to one end (such as the opposite-name terminal) of the third winding W3 via the first connecting wire 61, and the last odd-numbered single cell B m The negative terminal is electrically connected to the other end (same-name terminal) of the third winding W3 via the second connecting wire 62, when the last odd-numbered cell B needs to be connected. m When balancing is being performed, the corresponding switch can be closed to allow the third winding W3 to participate in the balancing adjustment.

[0072] Understandably, the second connecting line 62 is not only electrically connected to the positive terminal of each even-numbered cell, but also electrically connected to the negative terminal of each odd-numbered cell.

[0073] Of course, in other embodiments, an additional connecting line can also be provided to connect the last odd-numbered cell B. m The negative terminal is electrically connected to the other end of the third winding W3. In this embodiment, the last odd-numbered cell B in the battery pack 200 is connected... m The negative terminal is electrically connected to the second connection line 62, eliminating the need for additional connection lines and further simplifying the circuit topology.

[0074] In some embodiments, such as Figure 2 or Figure 3 As shown, the battery management system also includes a fourth switch 4, and at least one end of the first winding W1 is electrically connected to the switch group 10 through the fourth switch 4.

[0075] As an example, the opposite-named end of the first winding W1 is electrically connected to the switch group 10 via the fourth switch 4. Of course, in other embodiments, it can also be designed such that the same-named end of the first winding W1 is electrically connected to the switch group 10 via the fourth switch 4; or, both the opposite-named end and the same-named end of the first winding W1 are electrically connected to the switch group 10 via the third switch 3.

[0076] When equalization adjustment of a single cell is required, the first switch 1 and the fourth switch 4, which are electrically connected to the positive and negative terminals of that cell, are turned on to initiate equalization adjustment. When equalization adjustment is not required, the fourth switch 4 is turned off. Even if the first switch connected to a single cell is mistakenly turned on while the fourth switch 4 is off, equalization adjustment will not be initiated. In this embodiment, by setting the fourth switch 4, a double safety measure is designed, which improves the reliability of the circuit.

[0077] In some embodiments, such as Figure 2 or Figure 3 As shown, at least one of the first switch 1, the second switch 2, the third switch 3, and the fourth switch 4 includes a bidirectional switching transistor.

[0078] A bidirectional switching transistor consists of two MOSFETs connected back-to-back in series, and can bidirectionally block current through a control signal.

[0079] For example, the first switch 1 includes a bidirectional switching transistor, and the two MOSFETs included in the first switch 1 connected to the positive terminal of the first single cell B1 are respectively labeled S. 1（a） S 1（b） The first switch 1, which connects the negative terminal of the first cell B1 and the positive terminal of the second cell B2, includes two MOSFETs labeled S. 2（a） S 2（b） The first switch 1, whose negative terminal of the second cell B2 and positive terminal of the third cell B3 are connected, includes two MOSFETs labeled S. 3（a） S 3（b） And so on.

[0080] The second switch 2 includes two MOSFETs labeled S. 21 S 22 .

[0081] The third switch 3 includes two MOSFETs labeled S. 31 S 32 .

[0082] The second MOSFET included in the fourth switch 4 is labeled S. 41 S 42 .

[0083] Two MOSFETs connected end-to-end can achieve balanced bidirectional energy transfer. Taking the two MOSFETs of the first switch as an example, such as... Figure 4 As shown, taking single cell B as an example. n Let's take an example to explain how it works:

[0084] For example, in single cell B n When the energy is at its highest, then during balanced operation, cell B... n Energy needs to be released, at which point the control circuit outputs a high level to turn on the MOSFET S. n（a） With S n+1（b） Through MOSFET S n（a） With S n+1（b） and MOSFET S n（b） With S n+1（a） The freewheeling diode releases energy to reduce the single cell B. n Energy.

[0085] For example, in single cell B n When the energy is at its lowest, then during the equilibrium operation, cell B... n Energy needs to be absorbed, at which point the control circuit outputs a high level to turn on the MOSFET S.n（b） With S n+1（a）， Through MOSFET S n（b） With S n+1（a） And through MOSFET S n（a） With S n+1（b） The freewheeling diode absorbs energy to improve the performance of the single cell B. n Energy.

[0086] In this embodiment, since bidirectional MOSFETs have advantages over relay switches in terms of speed, lifespan, reliability, lack of physical contacts, absence of mechanical wear and arc erosion, and bidirectional conduction control capability, when the switch includes a bidirectional switching transistor, it is possible to more accurately control the charging or discharging of individual batteries, thereby improving circuit reliability.

[0087] As described above, the battery management system provided in this application embodiment can achieve balanced adjustment between any two individual cells, that is, it can enable charging and discharging between any two individual cells. Specifically, the first winding W1 and the second winding W2 form a flyback converter, enabling energy transfer between any individual cell and any even-numbered individual cell. The first winding W1 and the third winding W3 form a flyback converter, enabling energy transfer between any individual cell and any odd-numbered individual cell.

[0088] For example, if the absolute value of the voltage difference between two individual cells is greater than a preset threshold, equalization adjustment of the two individual cells can be initiated to reduce the energy difference between the two individual cells.

[0089] In some embodiments, the battery management system is configured to: when the absolute value of the difference between the voltage of the i-th individual cell and the voltage of the j-th individual cell in the battery pack is greater than a preset threshold, and the j-th individual cell is an even-numbered individual cell in the battery pack, the first switch connected to the i-th individual cell is turned on, the first switch connected to the j-th individual cell is turned on, and the second switch is turned on.

[0090] The i-th cell can be either an odd-numbered cell or an even-numbered cell.

[0091] As an example, the i-th cell is an odd-numbered cell, and the j-th cell is an even-numbered cell. Please refer to [reference needed]. Figure 5Taking the i-th cell as the first cell and the j-th cell as the fourth cell as an example, if the voltage of the first cell B1 is greater than the voltage of the fourth cell B4, and the absolute value of the difference between the voltage of the first cell B1 and the voltage of the fourth cell B4 is greater than a preset threshold, the state of the corresponding switch can be controlled so that the first cell B1 releases energy to the first winding W1, and the fourth cell B4 absorbs energy from the second winding W2.

[0092] For example, in the first time period, the MOSFET S 1（a） S 2（b） and S 42 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 1（a） S 2（b） S 42 and MOSFET S 1（b） S 2（a） S 41 The freewheeling diodes together form an energy release circuit, enabling the first single cell B1 to release energy to the first winding W1.

[0093] In the second time period, MOSFET S 4（b） S 5（a） S 22 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 4（b） S 5（a） S 22 And through MOSFET S 4（a） S 5（b） S 21 The freewheeling diodes together form an energy absorption circuit, enabling the fourth cell B4 to absorb energy from the second winding W2.

[0094] For example, when balancing the first cell B1 and the fourth cell B4, the battery management system may alternately execute the first time period and the second time period until the absolute value of the difference between the voltage of the first cell B1 and the voltage of the fourth cell B4 is less than or equal to a preset threshold.

[0095] As another example, the i-th cell is an even-numbered cell, and the j-th cell is also an even-numbered cell. Please refer to [reference needed]. Figure 6 Taking the i-th cell as the second cell and the j-th cell as the fourth cell as an example, if the voltage of the second cell B2 is greater than the voltage of the fourth cell B4, and the absolute value of the difference between the voltage of the second cell B2 and the voltage of the fourth cell B4 is greater than a preset threshold, the state of the corresponding switch can be controlled so that the second cell B2 releases energy to the first winding W1, and the fourth cell B4 absorbs energy from the second winding W2.

[0096] For example, in the third time period, the MOSFET S 2（a） S 3（b） and S 42 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 2（a） S 3（b） S 42 and MOSFET S 2（b） S 3（a） S 41 The freewheeling diodes together form an energy release circuit, enabling the second single cell B2 to release energy to the first winding W1.

[0097] In the fourth time period, the MOSFET S 4（b） S 5（a） S 22 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 4（b） S 5（a） S 22 And through MOSFET S 4（a） S 5（b） S 21 The freewheeling diodes together form an energy absorption circuit, enabling the fourth cell B4 to absorb energy from the second winding W2.

[0098] For example, when balancing the second cell B2 and the fourth cell B4, the battery management system may alternately execute the third and fourth time periods until the absolute value of the difference between the voltage of the second cell B2 and the voltage of the fourth cell B4 is less than or equal to a preset threshold.

[0099] According to the embodiments of this application, the i-th single cell is any single cell, the j-th single cell is any even-numbered single cell, the first switch connected to the i-th single cell is turned on, the first switch connected to the j-th single cell is turned on, and the second switch is turned on. In this way, energy balance between any single cell and any even-numbered single cell can be achieved.

[0100] In some embodiments, the battery management system is configured to: when the absolute value of the difference between the voltage of the i-th cell and the voltage of the j-th cell in the battery pack is greater than a preset threshold, and the j-th cell is an odd-numbered cell in the battery pack, the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the third switch is turned on.

[0101] The i-th cell can be either an odd-numbered cell or an even-numbered cell.

[0102] As an example, the i-th cell is an odd-numbered cell, and the j-th cell is also an odd-numbered cell. Please refer to [reference needed]. Figure 7 Taking the i-th cell as the first cell and the j-th cell as the third cell as an example, if the voltage of the first cell B1 is greater than the voltage of the third cell B3, and the absolute value of the difference between the voltage of the first cell B1 and the voltage of the third cell B3 is greater than a preset threshold, the state of the corresponding switch can be controlled so that the first cell B1 releases energy to the first winding W1, and the third cell B3 absorbs energy from the third winding W3.

[0103] For example, in the fifth time period, the MOSFET S 1（a） S 2（b） and S 42 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 1（a） S 2（b） S 42 and MOSFET S 1（b） S 2（a） S 41 The freewheeling diodes together form an energy release circuit, enabling the first single cell B1 to release energy to the first winding W1.

[0104] In the sixth time period, the MOSFET S 4（b） S 5（a） S 31 When the transistor is turned on, other MOSFETs are turned off, and power flows through the MOSFET's S... 4（b） S 5（a） S 31 And through MOSFET S 4（a） S 5（b） S 32 The freewheeling diodes together form an energy absorption circuit, enabling the third cell B3 to absorb energy from the third winding W3.

[0105] For example, when balancing the first cell B1 and the third cell B3, the battery management system may alternately execute the fifth and sixth time periods until the absolute value of the difference between the voltage of the first cell B1 and the voltage of the third cell B3 is less than or equal to a preset threshold.

[0106] According to the embodiments of this application, the i-th single cell is any single cell, the j-th single cell is any odd-numbered single cell, the first switch connected to the i-th single cell is turned on, the first switch connected to the j-th single cell is turned on, and the third switch is turned on. In this way, energy balance between any single cell and any odd-numbered single cell can be achieved.

[0107] In some embodiments, the i-th cell and the j-th cell are the two cells with the highest and lowest voltages in the battery pack.

[0108] The system can identify the highest and lowest voltage cells in the battery pack. If the voltage difference between the highest and lowest voltage cells exceeds a preset threshold, equalization adjustment is initiated. When the highest and lowest voltage cells are odd-numbered and even-numbered cells respectively, the battery management system operates as follows: Figure 5 As shown. When both the highest-voltage and lowest-voltage single-cell cells are even-numbered cells, the battery management system's operating mode can be as follows: Figure 6 As shown. When both the cell with the highest voltage and the cell with the lowest voltage are odd-numbered cells, the battery management system can operate as follows: Figure 7 As shown. In this way, energy balance can be achieved between any single cell with the highest voltage and any single cell with the lowest voltage, without affecting the other single cells that do not need to be balanced.

[0109] In this embodiment, when the voltage difference between the single cell with the highest voltage and the single cell with the lowest voltage in the battery pack is greater than a preset threshold, equalization control is initiated, resulting in a high equalization speed.

[0110] This application also provides a battery device. For example... Figure 8 As shown, the battery device 1000 includes a battery pack 200 and a battery management system 100. The battery management system 100 includes the battery management system in any of the above embodiments. It is understood that the battery device has the beneficial effects of the battery management system provided in the embodiments of this application. For details, please refer to the specific descriptions of the battery management system in the above embodiments, which will not be repeated here.

[0111] Based on the same technical concept, this application also provides an electrical device. The electrical device includes a battery device, and the battery device includes the battery management system in any of the above embodiments. It is understood that the electrical device has the beneficial effects of the battery management system provided in the embodiments of this application. For details, please refer to the specific descriptions of the battery management system in the above embodiments, which will not be repeated here.

[0112] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0113] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery management system, characterized in that, Includes switchgear, second switch, third switch, and bidirectional transformer; The switch group is electrically connected to each individual battery cell in the battery pack, and the switch group includes a plurality of first switches; The bidirectional transformer includes a first winding, a second winding, and a third winding. The first winding is coupled to the second winding and the third winding respectively. The first winding is electrically connected to each individual cell in the battery pack through the switch group. The second winding is electrically connected to each even-numbered individual cell in the battery pack through the second switch and the switch group. The third winding is electrically connected to each odd-numbered individual cell in the battery pack through the third switch and the switch group.

2. The battery management system according to claim 1, characterized in that, The number of first switches in the switch group is one more than the number of individual cells in the battery pack; The positive terminal of each odd-numbered individual cell in the battery pack is electrically connected to the first connecting line via the first switch. The positive terminal of each even-numbered cell in the battery pack is electrically connected to the second connecting line via the first switch. One end of the first winding is electrically connected to the first connecting line, and the other end of the first winding is electrically connected to the second connecting line. One end of the second winding is electrically connected to the first connecting line, and the other end of the second winding is electrically connected to the second connecting line. One end of the third winding is electrically connected to the first connecting line, and the other end of the third winding is electrically connected to the second connecting line. Furthermore, at least one of the first connecting line and the second connecting line is electrically connected to the second winding via the second switch, and at least one of the first connecting line and the second connecting line is electrically connected to the third winding via the third switch.

3. The battery management system according to claim 2, characterized in that, When the total number of individual cells in the battery pack is even, the negative terminal of the last individual cell in the battery pack is electrically connected to the first connecting line.

4. The battery management system according to claim 2, characterized in that, When the total number of individual cells in the battery pack is odd, the negative terminal of the last individual cell in the battery pack is electrically connected to the second connecting line.

5. The battery management system according to claim 1, characterized in that, The battery management system further includes a fourth switch, and at least one end of the first winding is electrically connected to the switch group via the fourth switch.

6. The battery management system according to claim 5, characterized in that, At least one of the first switch, the second switch, the third switch, and the fourth switch includes a bidirectional switching transistor.

7. The battery management system according to claim 1, characterized in that, The battery management system is configured as follows: If the absolute value of the difference between the voltage of the i-th cell and the voltage of the j-th cell in the battery pack is greater than a preset threshold, and the j-th cell is an even-numbered cell in the battery pack, then the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the second switch is turned on.

8. The battery management system according to claim 1, characterized in that, The battery management system is configured as follows: If the absolute value of the difference between the voltage of the i-th cell and the voltage of the j-th cell in the battery pack is greater than a preset threshold, and the j-th cell is an odd-numbered cell in the battery pack, then the first switch connected to the i-th cell is turned on, the first switch connected to the j-th cell is turned on, and the third switch is turned on.

9. The battery management system according to claim 7 or 8, characterized in that, The i-th cell and the j-th cell are the two cells with the highest and lowest voltages in the battery pack.

10. A battery device, characterized in that, Includes a battery pack and a battery management system as described in any one of claims 1-9.

11. An electrical appliance, characterized in that, Includes the battery device as described in claim 10.

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