A battery balancing control device, method and battery

Abstract

The present invention discloses a battery balancing control device, method and battery, the device comprises: a sampling unit, collecting battery parameters of the battery; a control unit, determining the battery balancing parameters according to the battery parameters of the battery; and, when the battery balancing parameters meet the set flyback balancing start-up conditions, controlling the battery cells to be balanced in the battery and the flyback balancing unit to form a loop, so as to use the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery; when the battery balancing parameters do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, controlling the battery cells to be balanced in the battery and the trickle balancing unit to form a loop, so as to use the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery. This scheme reduces the difficulty of battery balancing of large-capacity batteries by performing battery balancing according to different current sizes of battery charge and discharge characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and specifically relates to a battery balancing control device, method and battery, and more particularly to a large-capacity battery balancing control device, method and large-capacity battery based on a large-capacity battery balancing circuit. Background Art

[0002] Batteries have inconsistent charge due to production processes and environmental factors, which requires battery balancing management during use. Large-capacity batteries are prone to large charge differences due to their large capacity, which brings certain challenges to battery balancing.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a battery balancing control device, method and battery to solve the problem that battery balancing of large-capacity batteries is difficult, so as to achieve the effect of reducing the difficulty of battery balancing of large-capacity batteries by performing battery balancing according to different current sizes of battery charging and discharging characteristics.

[0005] The present invention provides a battery balancing control device, wherein the battery comprises: N battery cells, where N is a positive integer; the balancing circuit of the battery comprises: a flyback balancing unit and a trickle balancing unit; the battery balancing control device comprises: a sampling unit and a control unit; wherein the sampling unit is configured to collect battery parameters of the battery; the control unit is configured to determine the balancing parameters of the battery according to the battery parameters of the battery; and, when the balancing parameters of the battery meet the set flyback balancing start-up conditions, the battery cells to be balanced in the battery are controlled to form a loop with the flyback balancing unit, so that the flyback balancing unit is used to perform flyback balancing on the battery cells to be balanced in the battery; when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, the battery cells to be balanced in the battery are controlled to form a loop with the trickle balancing unit, so that the trickle balancing unit is used to perform trickle balancing on the battery cells to be balanced in the battery.

[0006] In some embodiments, the balancing parameters of the battery include: any one of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of the root mean square difference, the maximum value difference, and the average value difference corresponding to any one of the parameters of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

[0007] In some embodiments, the flyback balancing unit includes: a flyback circuit; the flyback circuit includes: a flyback converter, a first flyback switch tube module and a second flyback switch tube module; the first flyback switch tube module is arranged at the primary winding of the flyback converter; the second flyback switch tube module is arranged at the secondary winding of the flyback converter; the primary winding of the flyback converter can form a loop with the battery cells to be balanced in the battery; the secondary winding of the flyback converter can form a loop with a set storage battery.

[0008] In some embodiments, the trickle balancing unit includes: an energy-consuming balancing circuit; the energy-consuming balancing circuit includes: a resistance module and an energy-consuming switch tube module; wherein the resistance module and the energy-consuming switch tube module can form a loop with the battery cells to be balanced in the battery.

[0009] In some embodiments, the battery balancing circuit further includes: a first selection unit; the first selection unit includes: N+1 selection branches; among the N battery cells, the positive electrode of each of the battery cells is connected to one selection branch of the N+1 selection branches, and the negative electrode of each of the battery cells is connected to another selection branch of the N+1 selection branches; the battery balancing control device further includes: the control unit is further configured to determine the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an access instruction for accessing the battery cells to be balanced in the battery; the first selection unit is configured to connect the corresponding selection branches of the N+1 selection branches of the first selection unit itself that are connected to the positive and negative electrodes of the battery cells to be balanced in the battery when receiving the access instruction, so as to access the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit to form a loop with the flyback balancing unit or the trickle balancing unit.

[0010] In some implementations, in the N+1 selection branches, each selection branch includes: a first selection switch module and a second selection switch module; the first selection switch module and the second selection switch module are arranged in series.

[0011] In some embodiments, the battery balancing circuit further includes: a second selection unit; the second selection unit includes: a first polarity selection branch and a second polarity selection branch; the battery balancing control device further includes: the control unit is further configured to determine the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an opening instruction for enabling a polarity selection branch in the selection unit; the second selection unit is configured to enable a polarity selection branch in the second selection unit upon receiving the opening instruction, so as to process the polarity of the battery cells to be balanced in the battery, so that the battery cells to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

[0012] In some embodiments, in the first polarity selection branch and the second polarity selection branch, each polarity selection branch includes: a first polarity selection switch tube module and a second polarity selection switch tube module; the first polarity selection switch tube module and the second polarity selection switch tube module are arranged in parallel.

[0013] Matching the above device, the present invention further provides a battery, including: the above battery balancing control device.

[0014] Matching the above-mentioned battery, the present invention provides a battery balancing control method on another aspect, wherein the battery comprises: N battery cells, N being a positive integer; the balancing circuit of the battery comprises: a flyback balancing unit and a trickle balancing unit; the battery balancing control method comprises: collecting battery parameters of the battery; determining the balancing parameters of the battery according to the battery parameters; and, when the balancing parameters of the battery meet the set flyback balancing start-up conditions, controlling the battery cells to be balanced in the battery and the flyback balancing unit to form a loop, so as to utilize the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery; when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, controlling the battery cells to be balanced in the battery and the trickle balancing unit to form a loop, so as to utilize the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery.

[0015] In some embodiments, the balancing parameters of the battery include: any one of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of the root mean square difference, the maximum value difference, and the average value difference corresponding to any one of the parameters of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

[0016] In some embodiments, the battery balancing circuit further includes: a first selection unit; the first selection unit includes: N+1 selection branches; among the N battery cells, the positive electrode of each of the battery cells is connected to one selection branch among the N+1 selection branches, and the negative electrode of each of the battery cells is connected to another selection branch among the N+1 selection branches; the battery balancing control method further includes: determining the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issuing an access instruction for accessing the battery cells to be balanced in the battery; through the first selection unit, when receiving the access instruction, connecting the corresponding selection branches of the N+1 selection branches of the first selection unit itself that are connected to the positive and negative electrodes of the battery cells to be balanced in the battery, so as to access the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit, and forming a loop with the flyback balancing unit or the trickle balancing unit.

[0017] In some embodiments, the battery balancing circuit further includes: a second selection unit; the second selection unit includes: a first polarity selection branch and a second polarity selection branch; the battery balancing control method further includes: determining the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issuing an opening instruction for enabling a polarity selection branch in the selection unit; through the second selection unit, upon receiving the opening instruction, enabling a polarity selection branch in the second selection unit to process the polarity of the battery cells to be balanced in the battery, so that the battery cells to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

[0018] Therefore, the scheme of the present invention sets a large-capacity battery balancing circuit by using a large-current balancing circuit based on a flyback type and a trickle balancing circuit based on an energy consumption element. When the difference in the state of charge of the batteries is large, the large-current balancing circuit is used to perform large-current balancing on the batteries. When the difference in the state of charge of the batteries is small, the trickle balancing circuit is used to perform trickle balancing on the batteries, thereby achieving battery balancing of large-capacity batteries; thereby, by performing battery balancing according to different current sizes of battery charge and discharge characteristics, the difficulty of battery balancing of large-capacity batteries is reduced.

[0019] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of an embodiment of a battery balancing control device of the present invention;

[0022] Figure 2 A flow chart of an embodiment of a control method for a large-capacity battery balancing circuit;

[0023] Figure 3 A schematic diagram of the structure of an embodiment of a large-capacity battery equalization circuit;

[0024] Figure 4 A structural schematic diagram of an embodiment of a control system for a large-capacity battery balancing circuit;

[0025] Figure 5 A schematic flow chart of an embodiment of a battery balancing control method of the present invention;

[0026] Figure 6 A schematic diagram of a flow chart of an embodiment of selecting a battery cell in a method of the present invention;

[0027] Figure 7 The figure is a flow chart of an embodiment of the method of the present invention for processing the polarity of a battery cell. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] For example, for batteries such as lithium titanate, when the battery capacity is large, the difference is also large. Balancing is generally turned on when the battery is almost fully charged or almost fully discharged. If the battery balancing current is relatively small (such as conventional passive balancing of tens to hundreds of milliamperes), the balancing target cannot be achieved. Although conventional active balancing can provide a balancing current of several amperes or even tens of amperes, each solution also has various problems, such as complex topology, difficulty in implementation and high cost, and insufficient control to achieve precise balancing. The large-capacity battery here mainly refers to the battery that cannot achieve the battery balancing target by passive balancing. The failure to achieve the battery balancing target means that when the battery capacity is large, such as a lithium titanate battery with a capacity of 40 ampere-hours, the SOC between the battery cells is only 1% different, but it is 4 ampere-hours. If balancing is performed at 100 milliampere-hours, a 1% difference in SOC will also take 40 hours to balance. This balancing time is too long and does not meet the actual battery usage and balancing requirements.

[0030] Battery balancing methods are mainly divided into energy-consuming balancing and non-energy-consuming balancing. Energy-consuming balancing consumes the excess power of high-charged batteries through energy-consuming components. Non-energy-consuming balancing realizes power transfer between high-charged batteries and low-charged batteries through Buck-Boost circuits, Cuk circuits, flyback circuits, etc. Among them, Buck-Boost circuit is a buck or boost chopper, whose output average voltage U0 is greater than or less than the input voltage Ui, with opposite polarity and inductive transmission. Cuk circuit is a buck or boost chopper, whose output average voltage U0 is greater than or less than the input voltage Ui, with opposite polarity and capacitive transmission.

[0031] For large-capacity batteries, energy-consuming balancing can only be balanced with a small current due to the power limitation and heat dissipation problem of its energy-consuming components. Small current balancing requires a very long balancing time for large-capacity batteries with high charge differences, so it is not suitable for large-capacity batteries. Non-energy-consuming balancing can be balanced with a larger balancing current; but in non-energy-consuming balancing, Buck-Boost circuits and Cuk circuits are often only suitable for balancing adjacent battery cells. Balancing non-adjacent batteries with Buck-Boost circuits and Cuk circuits requires a complex circuit structure, which increases the cost and design complexity; and non-energy-consuming balancing based on flyback circuits, although a simple circuit can be used to achieve balancing of non-adjacent battery cells, the flyback circuit is affected by the characteristics of the flyback converter. To obtain a small balancing current, a very high-frequency driving signal and sampling signal are required, which is a problem for the controller, drive, sampling, and impulse problems in balancing. Balancing with a large current all the time is prone to over-balancing, thereby repeatedly starting balancing. Therefore, there is a lack of a fast and high-precision balancing circuit and method for large-capacity batteries.

[0032] According to an embodiment of the present invention, a battery balancing control device is provided. Figure 1 The structural schematic diagram of an embodiment of the battery balancing control device of the present invention is shown. The battery comprises: N battery cells, N is a positive integer. The battery has a balancing circuit. The balancing circuit of the battery comprises: a flyback balancing unit and a trickle balancing unit. The flyback balancing unit can perform flyback balancing on the battery cells to be balanced in the battery when the flyback balancing unit forms a loop with the battery cells to be balanced in the battery. The trickle balancing unit can perform trickle balancing on the battery cells to be balanced in the battery when the flyback balancing unit forms a loop with the battery cells to be balanced in the battery. The current of the flyback balancing is greater than the current of the trickle balancing. The flyback balancing unit is such as a flyback balancing loop. The trickle balancing unit is such as a trickle balancing loop.

[0033] The battery balancing control device comprises: a sampling unit and a control unit.

[0034] The sampling unit is configured to collect battery parameters of the battery, such as the voltage, temperature and other information of the battery.

[0035] The control unit is configured to determine a balancing parameter of the battery according to a battery parameter of the battery. And,

[0036] The control unit is further configured to control the battery cells to be balanced in the battery to form a loop with the flyback balancing unit when the balancing parameters of the battery meet the set flyback balancing start-up conditions, so as to use the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery. The flyback balancing start-up conditions are conditions for starting the flyback balancing unit so that the flyback balancing unit itself and the battery cells to be balanced in the battery form a loop.

[0037] The control unit is further configured to control the battery cells to be balanced in the battery to form a loop with the trickle balancing unit when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, so as to use the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery. The trickle balancing start-up conditions are conditions for turning on the trickle balancing unit so that the trickle balancing unit itself forms a loop with the battery cells to be balanced in the battery.

[0038] Of course, the control unit is also configured to control the flyback balancing unit and the trickle balancing unit to be turned off, that is, to control the battery to be disconnected from the flyback balancing unit and the trickle balancing unit, when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions and the set trickle balancing start-up conditions.

[0039] The control unit may be one controller or two controllers. In the case where there are two controllers, one controller may be used to determine the equalization parameters of the battery according to the battery parameters of the battery, and the other controller may be used to perform other processing.

[0040] The solution of the present invention designs a large-capacity battery balancing circuit and a balancing system and method, which includes a large current balancing circuit based on a flyback type (i.e., a flyback balancing circuit) and a trickle balancing circuit based on an energy-consuming element, and performs large current balancing on the battery when the difference in the battery state of charge is large. When the difference in the battery state of charge is small, using trickle balancing can balance the battery with different current sizes that meet the battery charge and discharge characteristics, while achieving rapid balancing and accurate balancing of large-capacity batteries, achieving a balancing process that meets the battery charge and discharge characteristics, and extending the battery life. In addition, the balancing speed is fast, and trickle balancing is used at the end of the balancing period, so that the balancing is smooth and accurate, and repeated balancing is avoided. In addition, the topology of the large-capacity battery balancing circuit is simple and the control is convenient, which effectively reduces the cost compared with other non-energy-consuming balancing.

[0041] In the solution of the present invention, an energy-consuming balancing circuit and a flyback balancing circuit are simultaneously constructed in the balancing circuit, which solves the problems in related solutions of too small balancing current or insufficiently precise balancing current control or complex balancing circuit structure. Compared with the prior art, it has a good balancing effect on large-capacity batteries.

[0042] Specifically, the flyback converter can achieve a balancing current of more than ten amperes or even tens of amperes, which is much larger than other solutions. For large-capacity batteries with high single-cell capacity, a larger balancing current is necessary, but the balancing circuit designed based on the flyback converter is difficult to achieve refined balancing current. Therefore, although the balancing speed is fast, the balancing effect is not good. Therefore, the solution of the present invention relies on the flyback converter (i.e., a large current balancing circuit based on the flyback type) to achieve large current balancing, but also constructs a balancing circuit based on energy-consuming devices (i.e., a trickle balancing circuit based on energy-consuming elements) to achieve refined balancing of the battery and reduce the difficulty of battery balancing of large-capacity batteries. In addition, the battery has charging and discharging characteristics and is suitable for charging currents of different sizes at different stages. The solution of the present invention can achieve this effect very well. In addition, the solution of the present invention makes high use of each device in the battery balancing circuit and has a high reuse rate. The main reason is that the two balancing circuits mentioned above achieve the effect of balancing multiple batteries with simple devices and simple control through the two parts of the circuit, namely, the shared circuit selector and the selection array. Compared with the existing solution, the cost reduction effect is obvious.

[0043] In some embodiments, the balancing parameters of the battery include: any one of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of the root mean square difference, the maximum value difference, and the average value difference corresponding to any one of the parameters of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

[0044] Specifically, the battery state of charge (i.e., SOC, which is the ratio of the remaining charge of the battery to the charge capacity), the remaining charge of the battery, the battery voltage, etc. can be selected as the balancing variables. Correspondingly, the root mean square difference or the maximum difference of the corresponding balancing variable, or the difference between the corresponding balancing variable and the average value, can be used as the balancing start judgment condition. Among them, the maximum difference represents the difference between the maximum value and the minimum value of the balancing variable, and the difference from the average value represents the difference between each value of the balancing variable and the average value.

[0045] The scheme of the present invention proposes an embodiment, using SOC as the balancing variable and the root mean square difference of SOC as the balancing start judgment condition. The scheme of the present invention has multiple advantages. For a single balancing method, the energy-consuming trickle balancing is slow and not suitable for large-capacity battery balancing. In non-energy-consuming balancing, Cuk, Boost and other circuits are complex, difficult to control and costly when balancing multiple batteries. Flyback balancing is not suitable for small current balancing (small current balancing requires extremely high control frequency and sampling frequency, and the current impulse and oscillation problems are serious, and the balancing current is not accurate), resulting in low balancing accuracy. When the balancing is about to be completed, the balancing is repeatedly turned on, reducing the service life of the device. The scheme of the present invention enables different balancing circuits according to the balancing situation of the battery, which can achieve the two advantages of fast battery balancing and high accuracy. At the same time, the designed circuit topology is simple, easy to control and low cost.

[0046] Figure 2 FIG. 1 is a flow chart of an embodiment of a control method for a large-capacity battery balancing circuit. Figure 2 As shown, the control method of the large-capacity battery balancing circuit includes:

[0047] Step 1: The battery information acquisition module first collects information such as battery voltage and temperature, and then sends the collected data to another main control chip through the communication module.

[0048] Step 2: Another main control chip estimates the SOC of the battery and calculates the root mean square difference of the SOC.

[0049] Step 3: Determine whether the root mean square difference of the SOC is greater than the flyback balanced start-up condition: If so, execute steps 41 to 43. Otherwise, execute step 5.

[0050] Step 41 : If the RMS difference of the SOC is greater than the flyback balanced start-up condition, which is 0.03 in this embodiment, step 42 is executed.

[0051] Step 42, screen out the highest SOC battery and the lowest SOC battery, and calculate the balancing current size according to the battery charge and discharge curve, and then execute step 43.

[0052] Step 43: Perform flyback discharge on the battery with the highest SOC and flyback charge on the battery with the lowest SOC with the calculated balancing current, and then return to step 1.

[0053] Step 51 : If the RMS difference of the SOC is greater than the trickle balance start condition but not greater than the flyback balance start condition, in this embodiment, the trickle start condition is 0.02, then execute step 52 .

[0054] Step 52: Filter out the battery with the highest SOC, and then execute step 53.

[0055] Step 53: trickle discharge the battery with the highest SOC, and then return to step 1. If the root mean square difference of the SOC is not greater than the trickle balancing start condition, return to step 1.

[0056] In some embodiments, in addition to using the RMS difference of the battery state of charge as the balancing start judgment condition, the difference between the maximum state of charge and the minimum state of charge of the battery can also be used as the judgment condition. In addition to using the battery state of charge as the balancing variable, the battery voltage can also be used as the balancing variable.

[0057] Specifically, the battery information is collected to obtain the state of charge of each cell, and the maximum difference in the battery state of charge is obtained by subtracting the SOC of the cell with the highest charge in the battery system from the SOC of the cell with the lowest charge. The maximum difference is compared with the flyback balancing start-up condition and the trickle balancing start-up condition to determine whether to turn on flyback balancing or trickle balancing. The specific start-up conditions can be set to 3% for the flyback balancing start-up condition and 2.8% for the trickle balancing start-up condition. Of course, the specific setting depends on the SOC estimation accuracy and the balancing target.

[0058] When the battery voltage is used as the balancing variable, the battery voltage is directly collected. In the specific judgment process, the state of charge in the process of using SOC as the balancing target is directly replaced by the battery voltage. Generally speaking, it is simple and easy to use voltage as the balancing object, but it is more difficult to use the state of charge as the balancing object. The balancing effect is more accurate than that of using voltage as the balancing object. The specific effect depends on the estimation method of the state of charge.

[0059] In some embodiments, the flyback balancing unit includes a flyback circuit, a flyback converter, a first flyback switch module, and a second flyback switch module. The first flyback switch module is such as an N-channel MOS tube M1, and the second flyback switch module is such as an N-channel MOS tube M2.

[0060] The first flyback switch tube module is arranged at the primary winding of the flyback converter. The second flyback switch tube module is arranged at the secondary winding of the flyback converter.

[0061] The primary winding of the flyback converter can form a loop with the battery cells to be balanced in the battery. The secondary winding of the flyback converter can form a loop with the set storage battery. The set storage battery is a storage battery for balancing, such as a 24V storage battery.

[0062] Figure 3 FIG. 1 is a schematic diagram of a structure of an embodiment of a large-capacity battery balancing circuit. Figure 3In the example shown, a non-energy-consuming balancing circuit is formed by a flyback converter, an N-channel MOS transistor M1, an N-channel MOS transistor M2, a primary current sampling module, and a secondary current sampling module. The N-channel MOS transistor M1 and the N-channel MOS transistor M2 form a balancing MOS module. The drain of the N-channel MOS transistor M3 is connected to the same-name end of the primary winding of the flyback converter. The opposite-name end of the primary winding of the flyback converter is connected to the drain of the N-channel MOS transistor M1. The source of the N-channel MOS transistor M1 is connected to the first end of the primary current sampling module. The source of the N-channel MOS transistor M11 is connected to the second end of the primary current sampling module. The opposite-name end of the secondary winding of the flyback converter is connected to the positive electrode of the 24V battery. The negative electrode of the 24V battery is grounded. The negative electrode of the 24V battery is also connected to the source of the N-channel MOS transistor M2 after passing through the secondary current sampling module. The drain of the N-channel MOS transistor M2 is connected to the same-name end of the secondary winding of the flyback converter.

[0063] In some embodiments, the trickle current balancing unit includes: an energy consumption balancing circuit. The energy consumption balancing circuit includes: a resistor module and an energy consumption switch tube module. The resistor module is such as resistor R1, and the switch tube module is such as N-channel MOS tube M11.

[0064] The resistance module and the energy consumption switch tube module can form a loop with the battery cells to be balanced in the battery.

[0065] exist Figure 3 In the example shown, the resistor R1 and the N-channel MOS transistor M11 form an energy-consuming balancing loop. The drain of the N-channel MOS transistor M3 is connected to the drain of the N-channel MOS transistor M11 through the resistor R1. The drain of the N-channel MOS transistor M6 is connected to the source of the N-channel MOS transistor M11. The source of the N-channel MOS transistor M11 is also grounded.

[0066] In some embodiments, the battery balancing circuit further includes: a first selection unit, such as a selection array. The first selection unit includes: N+1 selection branches. Among the N battery cells, the positive electrode of each of the battery cells is connected to one of the N+1 selection branches, and the negative electrode of each of the battery cells is connected to another selection branch of the N+1 selection branches.

[0067] The battery balancing control device also includes: a process of selecting battery cells.

[0068] The control unit is further configured to determine the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an access instruction for accessing the battery cells to be balanced in the battery. The access instruction is an instruction for accessing the battery cells to be balanced in the battery to the balancing circuit, such as an instruction for accessing the flyback balancing unit or the trickle balancing unit.

[0069] The first selection unit is configured to, upon receiving the access instruction, connect the corresponding selection branches among the N+1 selection branches of the first selection unit itself that are connected to the positive and negative electrodes of the battery cells to be balanced in the battery, so as to connect the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit, and form a loop with the flyback balancing unit or the trickle balancing unit.

[0070] In the scheme of the present invention, multiple batteries use the same flyback balancing and trickle balancing, and the balancing is divided into two processes, which can complete the variable current balancing that meets the battery charging and discharging characteristics, and the circuit is simple. That is to say, the balancing is divided into two processes, and the variable current balancing is implemented, which meets the battery charging and discharging characteristics. The flyback balancing is used to complete the main balancing process, with self-isolation, simple topology, and controllable balancing current. That is to say, the flyback balancing completes the main balancing process, the flyback balancing circuit is simple, the balancing current value can be set for balancing, and it has self-isolation. Multiple batteries share the trickle balancing circuit, only one MOS tube is required, and the trickle balancing mainly works at the end of the balancing period. Multiple batteries share the same trickle balancing, and the trickle balancing only works at the end of the balancing period, which is simple to control and low in cost. Therefore, the problems of slow balancing speed and low balancing accuracy of large-capacity batteries can be solved, and variable current balancing can be performed on large-capacity batteries. The initial balancing current is large, the balancing speed is fast, and the trickle balancing is performed at the end. The balancing is stable and accurate, and it meets the battery charging and discharging characteristics, extending the battery life. The balancing circuit is simple and low in cost.

[0071] The solution of the present invention proposes a large-capacity battery balancing circuit and a balancing method thereof. The designed balancing circuit includes a trickle balancing circuit and a flyback balancing circuit. When the balancing variable reaches the flyback balancing start-up condition, the flyback balancing circuit is turned on for balancing. When the balancing variable reaches the trickle balancing start-up condition and does not reach the flyback balancing start-up condition, the energy consumption balancing circuit is turned on for balancing. When the balancing variable neither reaches the flyback balancing start-up condition nor the trickle balancing start-up condition, the balancing is not turned on.

[0072] In some implementations, in the N+1 selection branches, each selection branch includes: a first selection switch module and a second selection switch module. The first selection switch module and the second selection switch module are arranged in series.

[0073] exist Figure 3 In the example shown, a selection array is formed by a P-channel MOS tube M8, a P-channel MOS tube M10, an N-channel MOS tube M7, and an N-channel MOS tube M9, and the selection array is used to select the balanced battery cells. The positive electrode of each battery cell is connected to the source of the N-channel MOS tube M7. The drain of the N-channel MOS tube M7 is connected to the source of the P-channel MOS tube M8. The drain of the P-channel MOS tube M8 is connected to the first input terminal of the loop selector. The negative electrode of each battery cell is connected to the source of the N-channel MOS tube M9. The drain of the N-channel MOS tube M9 is connected to the source of the P-channel MOS tube M10. The drain of the P-channel MOS tube M10 is connected to the second input terminal of the loop selector.

[0074] In some embodiments, the battery balancing circuit further includes: a second selection unit, such as a loop selector. The second selection unit includes: a first polarity selection branch and a second polarity selection branch. The second selection unit can process the polarity of the battery cells to be balanced in the battery when one polarity selection branch in the second selection unit is connected to the battery cells to be balanced in the battery, and the second selection unit is connected to the flyback balancing unit or the trickle balancing unit, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

[0075] The battery balancing control device also includes: a process of processing the polarity of the battery cells.

[0076] The control unit is further configured to determine the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and to issue an opening instruction for a polarity selection branch in the selection unit, that is, to issue an opening instruction for one of the first polarity selection branch and the second polarity selection branch in the selection unit.

[0077] The second selection unit is configured to, upon receiving the opening instruction, open a polarity selection branch in the second selection unit to process the polarity of the battery cells to be balanced in the battery, that is, according to the polarity of the battery cells to be balanced in the battery, the battery cells to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

[0078] In some embodiments, in the first polarity selection branch and the second polarity selection branch, each polarity selection branch includes: a first polarity selection switch tube module and a second polarity selection switch tube module. The first polarity selection switch tube module and the second polarity selection switch tube module are arranged in parallel.

[0079] like Figure 3 The large-capacity battery balancing circuit shown includes: a battery cell, a selection array, a circuit selector, an energy-consuming balancing circuit, a flyback balancing circuit, and a 24V storage battery. The battery cell is connected to the energy-consuming balancing circuit and the flyback balancing circuit respectively after being selected by the selection array and the circuit selector. The 24V storage battery is connected to the flyback balancing circuit.

[0080] exist Figure 3 In the example shown, N-channel MOS transistor M3, N-channel MOS transistor M4, N-channel MOS transistor M5, and N-channel MOS transistor M6. The drain of P-channel MOS transistor M8 is connected to the source of N-channel MOS transistor M3. The drain of P-channel MOS transistor M8 is also connected to the source of N-channel MOS transistor M4. The source of N-channel MOS transistor M3 serves as the first input end of the loop selector. The drain of N-channel MOS transistor M3 is connected to the first input end of the energy consumption type equalization circuit. The drain of N-channel MOS transistor M3 is also connected to the first input end of the flyback type equalization loop. The drain of N-channel MOS transistor M3 is also connected to the drain of N-channel MOS transistor M5. The drain of P-channel MOS transistor M10 is connected to the source of N-channel MOS transistor M5. The drain of P-channel MOS transistor M10 is also connected to the source of N-channel MOS transistor M6. The source of N-channel MOS transistor M5 serves as the second input end of the loop selector. The drain of the N-channel MOS transistor M6 is connected to the drain of the N-channel MOS transistor M4. The drain of the N-channel MOS transistor M6 is also connected to the second input end of the energy consumption type equalization circuit. The drain of the N-channel MOS transistor M6 is also connected to the second input end of the flyback type equalization loop. Figure 3 In the example shown, the gate of each MOS tube is connected to the controller to be turned on or off under the control of the controller.

[0081] exist Figure 3In the large-capacity battery balancing circuit shown, two balancing loops based on energy-consuming elements such as resistors and flyback converters are constructed. The two balancing loops can be turned on by their respective balancing MOS tubes to achieve fine balancing of small currents and fast balancing of large currents, which is conducive to achieving the balancing purpose of large-capacity batteries. In addition to requiring accurate balancing, large-capacity batteries also require fast balancing speed. In addition, the two balancing loops are constructed by the same loop selector and selection array, that is, when the number of balanced batteries increases, only the selection array channels corresponding to the number of batteries need to be increased, and the loop selector can achieve balancing of the opposite polarity of the batteries connected to the loop with one balancing loop. Compared with other schemes, balancing loops can be saved, and the control is simple, and only the balancing MOS tube of the corresponding loop needs to be controlled to turn on the loop. That is, compared with the related schemes, the large-capacity battery balancing circuit adopted by the scheme of the present invention has high utilization rate of each device, good balancing effect that can be implemented, simple control, and lower cost.

[0082] For example, six batteries require seven back-to-back MOSs as selection array channels, while seven batteries require eight back-to-back selection array channels. The subsequent loop selection and balancing loops in the circuit do not need to be changed.

[0083] The selection array will only connect one battery cell, and when the batteries are connected in series, the polarity of the connected batteries may be opposite. The role of the circuit selector is to determine the battery connection polarity according to the connected battery number and select the corresponding circuit to connect to the balancing circuit. In this way, all battery cells use the same circuit selector and balancing circuit when balancing, instead of each cell having a balancing circuit in other solutions.

[0084] In the balancing solutions based on topologies such as buck and boost, a balancing loop is set for each monomer, which has complex circuits, inconvenient control and high costs.

[0085] The circuit selector selects the access mode of the battery to ensure the connection polarity between the battery and the balancing circuit. When balancing is to be turned on, the MOS tube in the selection array connected to the target battery cell is turned on, and the MOS tube in the commutator is turned on according to the polarity of the battery connection, so that the positive electrode of the battery cell is connected to the upper end of the balancing circuit in the figure, and the negative electrode of the battery cell is connected to the lower end of the balancing circuit in the figure, and the corresponding balancing circuit is turned on and controlled according to the battery charge. Specifically, the parameters of the flyback converter should be calculated according to the input voltage, output voltage, peak current and other requirements according to the design method of the converter. The MOS tube should be selected to meet the maximum stress voltage. The resistance value of resistor R1 is calculated according to the input voltage and the target balancing current, and the package that meets this power requirement is selected. If there is no package type that meets the power, the resistance value and power can be made up by connecting resistors in series and parallel. The primary current sampling module and the secondary current sampling module can be a sampling circuit or current sensor composed of a sampling resistor, an operational amplifier and other signal conditioning circuits.

[0086] Figure 4 FIG. 1 is a schematic diagram of a control system for a large-capacity battery balancing circuit according to an embodiment of the present invention. Figure 4 As shown, the control system of the large-capacity battery balancing circuit includes: a balancing current sampling module, a balancing module, a controller, a battery information acquisition module, a communication module and a storage module. The balancing current sampling module is connected to the balancing module. The controller is connected to the balancing module, the controller, the communication module and the storage module respectively.

[0087] Figure 3 The system implementing the equalization of the large-capacity battery equalization circuit shown in the figure may include the following: Figure 4 The modules shown in the figure. Among them, the controller, the balancing module and the balancing current sampling module are the modules necessary for the implementation of the balancing action, the battery information acquisition module is the module required for the implementation of the balancing strategy, and the communication module and the storage module are optional modules. In this system, the controller can select any MCU (control unit) or DSP (digital signal processing unit) that meets the performance requirements. For example, the control chip model TMS320F28035 can be used as the controller. The main body of the balancing module is as follows Figure 3 The balancing circuit shown in the figure has the corresponding selection requirements in Figure 3 The example shown in the figure shows the balanced current sampling module. Figure 3In the primary current sampling and secondary current sampling parts, the solution of the present invention uses a current acquisition circuit composed of a sampling resistor and an operational amplifier and other signal conditioning circuits to perform balanced current acquisition. The battery information acquisition module is used to obtain battery voltage, temperature and other information for obtaining balanced variables. In this embodiment, SOC is used as the balanced variable, such as using an AFE (analog front end) chip model LTC6811 and its application circuit as a battery information acquisition module to obtain battery voltage and temperature. In this embodiment, there are optional communication modules and storage modules. In this embodiment, the calculation of SOC is not Figure 4 The controller TMS320F28035 is used for calculation, but is sent to another main control chip for calculation through the communication module. The communication module of this embodiment can use a CAN (controller area network) communication chip such as a chip with a signal of TD501. In addition, this embodiment stores the SOC root mean square difference of the large current non-energy consumption type balancing start condition and the SOC root mean square difference of the small current energy consumption type balancing start condition, as well as other system parameters and fault information in the storage module. The storage chip used in this embodiment is a chip with a model of GT25C512.

[0088] The solution of the present invention is a balancing circuit including a flyback balancing circuit and a trickle balancing circuit, and a related balancing system and method. By performing flyback balancing on the battery when the difference in the battery state of charge is large, and using trickle balancing when the difference in the battery state of charge is small, a balancing process that meets the battery charging and discharging characteristics can be achieved, and the battery service life can be extended. In addition, trickle balancing is used at the end of balancing, and the balancing is stable and accurate, which can simultaneously achieve rapid balancing and accurate balancing of large-capacity batteries.

[0089] The technical solution of the present invention is adopted, by using a large current balancing circuit based on a flyback type and a trickle balancing circuit based on an energy consumption element, a large capacity battery balancing circuit is set, when the difference in the state of charge of the battery is large, the large current balancing circuit is used to perform large current balancing on the battery, and when the difference in the state of charge of the battery is small, the trickle balancing circuit is used to perform trickle balancing on the battery, thereby realizing battery balancing of large capacity batteries. Thus, by performing battery balancing according to different current sizes of battery charge and discharge characteristics, the difficulty of battery balancing of large capacity batteries is reduced.

[0090] According to an embodiment of the present invention, a battery corresponding to the battery balancing control device is also provided. The battery may include: the battery balancing control device described above.

[0091] Since the processing and functions implemented by the battery of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0092] By adopting the technical solution of the present invention, a large-capacity battery balancing circuit is set by using a large-current balancing circuit based on a flyback type and a trickle balancing circuit based on an energy consumption element. When the difference in the states of charge of the batteries is large, the large-current balancing circuit is used to perform large-current balancing on the batteries. When the difference in the states of charge of the batteries is small, the trickle balancing circuit is used to perform trickle balancing on the batteries. Battery balancing of large-capacity batteries is achieved, and rapid and precise balancing of large-capacity batteries can be achieved, which complies with the battery charging and discharging characteristics and can extend the battery life.

[0093] According to an embodiment of the present invention, a battery balancing control method corresponding to the battery balancing control device is also provided, such as Figure 5 A flow chart of an embodiment of a battery balancing control method of the present invention is shown. The battery comprises: N battery cells, where N is a positive integer. The battery has a balancing circuit. The balancing circuit of the battery comprises: a flyback balancing unit and a trickle balancing unit. The flyback balancing unit can perform flyback balancing on the battery cells to be balanced in the battery when the flyback balancing unit forms a loop with the battery cells to be balanced in the battery. The trickle balancing unit can perform trickle balancing on the battery cells to be balanced in the battery when the flyback balancing unit forms a loop with the battery cells to be balanced in the battery. The current of the flyback balancing is greater than the current of the trickle balancing. The flyback balancing unit is such as a flyback balancing loop. The trickle balancing unit is such as a trickle balancing loop.

[0094] The battery balancing control method includes: steps S110 to S140.

[0095] In step S110, the battery parameters of the battery are collected, such as the voltage, temperature and other information of the battery.

[0096] At step S120, the balancing parameters of the battery are determined according to the battery parameters of the battery. And,

[0097] At step S130, when the balancing parameters of the battery meet the set flyback balancing start-up conditions, the battery cells to be balanced in the battery are controlled to form a loop with the flyback balancing unit, so as to use the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery. The flyback balancing start-up conditions are conditions for turning on the flyback balancing unit so that the flyback balancing unit itself and the battery cells to be balanced in the battery form a loop.

[0098] At step S140, when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, the battery cells to be balanced in the battery are controlled to form a loop with the trickle balancing unit, so as to use the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery. The trickle balancing start-up conditions are conditions for turning on the trickle balancing unit so that the trickle balancing unit itself forms a loop with the battery cells to be balanced in the battery.

[0099] Of course, when the balancing parameters of the battery do not meet the set flyback balancing start-up conditions and the set trickle balancing start-up conditions, the flyback balancing unit and the trickle balancing unit are controlled to be turned off, that is, the battery is controlled to be disconnected from the flyback balancing unit and the trickle balancing unit.

[0100] The solution of the present invention designs a large-capacity battery balancing circuit and a balancing system and method, which includes a large current balancing circuit based on a flyback type (i.e., a flyback balancing circuit) and a trickle balancing circuit based on an energy-consuming element, and performs large current balancing on the battery when the difference in the battery state of charge is large. When the difference in the battery state of charge is small, using trickle balancing can balance the battery with different current sizes that meet the battery charge and discharge characteristics, while achieving rapid balancing and accurate balancing of large-capacity batteries, achieving a balancing process that meets the battery charge and discharge characteristics, and extending the battery life. In addition, the balancing speed is fast, and trickle balancing is used at the end of the balancing period, so that the balancing is smooth and accurate, and repeated balancing is avoided. In addition, the topology of the large-capacity battery balancing circuit is simple and the control is convenient, which effectively reduces the cost compared with other non-energy-consuming balancing.

[0101] In the solution of the present invention, an energy-consuming balancing circuit and a flyback balancing circuit are simultaneously constructed in the balancing circuit, which solves the problems in related solutions of too small balancing current or insufficiently precise balancing current control or complex balancing circuit structure. Compared with the prior art, it has a good balancing effect on large-capacity batteries.

[0102] Specifically, the flyback converter can achieve a balancing current of more than ten amperes or even tens of amperes, which is much larger than other solutions. For large-capacity batteries with high single-cell capacity, a larger balancing current is necessary, but the balancing circuit designed based on the flyback converter is difficult to achieve refined balancing current. Therefore, although the balancing speed is fast, the balancing effect is not good. Therefore, the solution of the present invention relies on the flyback converter (i.e., a large current balancing circuit based on the flyback type) to achieve large current balancing, but also constructs a balancing circuit based on energy-consuming devices (i.e., a trickle balancing circuit based on energy-consuming elements) to achieve refined balancing of the battery and reduce the difficulty of battery balancing of large-capacity batteries. In addition, the battery has charging and discharging characteristics and is suitable for charging currents of different sizes at different stages. The solution of the present invention can achieve this effect very well. In addition, the solution of the present invention makes high use of each device in the battery balancing circuit and has a high reuse rate. The main reason is that the two balancing circuits mentioned above achieve the effect of balancing multiple batteries with simple devices and simple control through the two parts of the circuit, namely, the shared circuit selector and the selection array. Compared with the existing solution, the cost reduction effect is obvious.

[0103] In some embodiments, the balancing parameters of the battery include: any one of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of the root mean square difference, the maximum value difference, and the average value difference corresponding to any one of the parameters of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

[0104] Specifically, the battery state of charge (i.e., SOC, which is the ratio of the remaining charge of the battery to the charge capacity), the remaining charge of the battery, the battery voltage, etc. can be selected as the balancing variables. Correspondingly, the root mean square difference or the maximum difference of the corresponding balancing variable, or the difference between the corresponding balancing variable and the average value, can be used as the balancing start judgment condition. Among them, the maximum difference represents the difference between the maximum value and the minimum value of the balancing variable, and the difference from the average value represents the difference between each value of the balancing variable and the average value.

[0105] The scheme of the present invention proposes an embodiment, using SOC as the balancing variable and the root mean square difference of SOC as the balancing start judgment condition. The scheme of the present invention has multiple advantages. For a single balancing method, the energy-consuming trickle balancing is slow and not suitable for large-capacity battery balancing. In non-energy-consuming balancing, Cuk, Boost and other circuits are complex, difficult to control and costly when balancing multiple batteries. Flyback balancing is not suitable for small current balancing (small current balancing requires extremely high control frequency and sampling frequency, and the current impulse and oscillation problems are serious, and the balancing current is not accurate), resulting in low balancing accuracy. When the balancing is about to be completed, the balancing is repeatedly turned on, reducing the service life of the device. The scheme of the present invention enables different balancing circuits according to the balancing situation of the battery, which can achieve the two advantages of fast battery balancing and high accuracy. At the same time, the designed circuit topology is simple, easy to control and low cost.

[0106] Figure 2 FIG. 1 is a flow chart of an embodiment of a control method for a large-capacity battery balancing circuit. Figure 2 As shown, the control method of the large-capacity battery balancing circuit includes:

[0107] Step 1: The battery information acquisition module first collects information such as battery voltage and temperature, and then sends the collected data to another main control chip through the communication module.

[0108] Step 2: Another main control chip estimates the SOC of the battery and calculates the root mean square difference of the SOC.

[0109] Step 3: Determine whether the root mean square difference of the SOC is greater than the flyback balanced start-up condition: If so, execute steps 41 to 43. Otherwise, execute step 5.

[0110] Step 41 : If the RMS difference of the SOC is greater than the flyback balanced start-up condition, which is 0.03 in this embodiment, step 42 is executed.

[0111] Step 42, screen out the highest SOC battery and the lowest SOC battery, and calculate the balancing current size according to the battery charge and discharge curve, and then execute step 43.

[0112] Step 43: Perform flyback discharge on the battery with the highest SOC and flyback charge on the battery with the lowest SOC with the calculated balancing current, and then return to step 1.

[0113] Step 51 : If the RMS difference of the SOC is greater than the trickle balance start condition but not greater than the flyback balance start condition, in this embodiment, the trickle start condition is 0.02, then execute step 52 .

[0114] Step 52: Filter out the battery with the highest SOC, and then execute step 53.

[0115] Step 53: trickle discharge the battery with the highest SOC, and then return to step 1. If the root mean square difference of the SOC is not greater than the trickle balancing start condition, return to step 1.

[0116] In some embodiments, in addition to using the RMS difference of the battery state of charge as the balancing start judgment condition, the difference between the maximum state of charge and the minimum state of charge of the battery can also be used as the judgment condition. In addition to using the battery state of charge as the balancing variable, the battery voltage can also be used as the balancing variable.

[0117] Figure 3 FIG. 1 is a schematic diagram of a structure of an embodiment of a large-capacity battery balancing circuit. Figure 3 In the example shown, a non-energy-consuming balancing circuit is formed by a flyback converter, an N-channel MOS transistor M1, an N-channel MOS transistor M2, a primary current sampling module, and a secondary current sampling module. The N-channel MOS transistor M1 and the N-channel MOS transistor M2 form a balancing MOS module. The drain of the N-channel MOS transistor M3 is connected to the same-name end of the primary winding of the flyback converter. The opposite-name end of the primary winding of the flyback converter is connected to the drain of the N-channel MOS transistor M1. The source of the N-channel MOS transistor M1 is connected to the first end of the primary current sampling module. The source of the N-channel MOS transistor M11 is connected to the second end of the primary current sampling module. The opposite-name end of the secondary winding of the flyback converter is connected to the positive electrode of the 24V battery. The negative electrode of the 24V battery is grounded. The negative electrode of the 24V battery is also connected to the source of the N-channel MOS transistor M2 after passing through the secondary current sampling module. The drain of the N-channel MOS transistor M2 is connected to the same-name end of the secondary winding of the flyback converter.

[0118] exist Figure 3 In the example shown, the resistor R1 and the N-channel MOS transistor M11 form an energy-consuming balancing loop. The drain of the N-channel MOS transistor M3 is connected to the drain of the N-channel MOS transistor M11 through the resistor R1. The drain of the N-channel MOS transistor M6 is connected to the source of the N-channel MOS transistor M11. The source of the N-channel MOS transistor M11 is also grounded.

[0119] In some embodiments, the battery balancing circuit further includes: a first selection unit, such as a selection array. The first selection unit includes: N+1 selection branches. Among the N battery cells, the positive electrode of each of the battery cells is connected to one of the N+1 selection branches, and the negative electrode of each of the battery cells is connected to another selection branch of the N+1 selection branches.

[0120] The battery balancing control method further includes: a process of selecting battery cells.

[0121] Combine the following Figure 6 The flowchart of an embodiment of selecting a battery cell in the method of the present invention further illustrates the specific process of selecting a battery cell, including: step S210 and step S220.

[0122] Step S210, determining the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issuing access instructions for accessing the battery cells to be balanced in the battery. The access instructions are instructions for accessing the battery cells to be balanced in the battery to the balancing circuit, such as instructions for accessing the flyback balancing unit or the trickle balancing unit.

[0123] Step S220: When the access instruction is received, the first selection unit connects the corresponding selection branches of the N+1 selection branches of the first selection unit itself that are connected to the positive and negative electrodes of the battery cells to be balanced in the battery, so as to connect the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit to form a loop with the flyback balancing unit or the trickle balancing unit.

[0124] In the scheme of the present invention, multiple batteries use the same flyback balancing and trickle balancing, and the balancing is divided into two processes, which can complete the variable current balancing that meets the battery charging and discharging characteristics, and the circuit is simple. That is to say, the balancing is divided into two processes, and the variable current balancing is implemented, which meets the battery charging and discharging characteristics. The flyback balancing is used to complete the main balancing process, with self-isolation, simple topology, and controllable balancing current. That is to say, the flyback balancing completes the main balancing process, the flyback balancing circuit is simple, the balancing current value can be set for balancing, and it has self-isolation. Multiple batteries share the trickle balancing circuit, only one MOS tube is required, and the trickle balancing mainly works at the end of the balancing period. Multiple batteries share the same trickle balancing, and the trickle balancing only works at the end of the balancing period, which is simple to control and low in cost. Therefore, the problems of slow balancing speed and low balancing accuracy of large-capacity batteries can be solved, and variable current balancing can be performed on large-capacity batteries. The initial balancing current is large, the balancing speed is fast, and the trickle balancing is performed at the end. The balancing is stable and accurate, and it meets the battery charging and discharging characteristics, extending the battery life. The balancing circuit is simple and low in cost.

[0125] The solution of the present invention proposes a large-capacity battery balancing circuit and a balancing method thereof. The designed balancing circuit includes a trickle balancing circuit and a flyback balancing circuit. When the balancing variable reaches the flyback balancing start-up condition, the flyback balancing circuit is turned on for balancing. When the balancing variable reaches the trickle balancing start-up condition and does not reach the flyback balancing start-up condition, the energy consumption balancing circuit is turned on for balancing. When the balancing variable neither reaches the flyback balancing start-up condition nor the trickle balancing start-up condition, the balancing is not turned on.

[0126] exist Figure 3 In the example shown, a selection array is formed by a P-channel MOS tube M8, a P-channel MOS tube M10, an N-channel MOS tube M7, and an N-channel MOS tube M9, and the selection array is used to select the balanced battery cells. The positive electrode of each battery cell is connected to the source of the N-channel MOS tube M7. The drain of the N-channel MOS tube M7 is connected to the source of the P-channel MOS tube M8. The drain of the P-channel MOS tube M8 is connected to the first input terminal of the loop selector. The negative electrode of each battery cell is connected to the source of the N-channel MOS tube M9. The drain of the N-channel MOS tube M9 is connected to the source of the P-channel MOS tube M10. The drain of the P-channel MOS tube M10 is connected to the second input terminal of the loop selector.

[0127] In some embodiments, the battery balancing circuit further includes: a second selection unit, such as a loop selector. The second selection unit includes: a first polarity selection branch and a second polarity selection branch. The second selection unit can process the polarity of the battery cells to be balanced in the battery when one polarity selection branch in the second selection unit is connected to the battery cells to be balanced in the battery, and the second selection unit is connected to the flyback balancing unit or the trickle balancing unit, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

[0128] The battery balancing control method further includes: a process of processing the polarity of the battery cells.

[0129] Combine the following Figure 7 The flowchart of an embodiment of processing the polarity of a battery cell in the method of the present invention further illustrates the specific process of processing the polarity of a battery cell, including: step S310 and step S320.

[0130] Step S310, determining the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issuing an opening instruction for a polarity selection branch in the selection unit, that is, issuing an opening instruction for one of the first polarity selection branch and the second polarity selection branch in the selection unit.

[0131] Step S320, through the second selection unit, when the opening instruction is received, a polarity selection branch in the second selection unit is opened to process the polarity of the battery cell to be balanced in the battery, that is, according to the polarity of the battery cell to be balanced in the battery, the battery cell to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cell to be balanced in the battery is balanced by the flyback balancing unit or the trickle balancing unit.

[0132] like Figure 3 The large-capacity battery balancing circuit shown includes: a battery cell, a selection array, a circuit selector, an energy-consuming balancing circuit, a flyback balancing circuit, and a 24V storage battery. The battery cell is connected to the energy-consuming balancing circuit and the flyback balancing circuit respectively after being selected by the selection array and the circuit selector. The 24V storage battery is connected to the flyback balancing circuit.

[0133] exist Figure 3 In the example shown, N-channel MOS transistor M3, N-channel MOS transistor M4, N-channel MOS transistor M5, and N-channel MOS transistor M6. The drain of P-channel MOS transistor M8 is connected to the source of N-channel MOS transistor M3. The drain of P-channel MOS transistor M8 is also connected to the source of N-channel MOS transistor M4. The source of N-channel MOS transistor M3 serves as the first input end of the loop selector. The drain of N-channel MOS transistor M3 is connected to the first input end of the energy consumption type equalization circuit. The drain of N-channel MOS transistor M3 is also connected to the first input end of the flyback type equalization loop. The drain of N-channel MOS transistor M3 is also connected to the drain of N-channel MOS transistor M5. The drain of P-channel MOS transistor M10 is connected to the source of N-channel MOS transistor M5. The drain of P-channel MOS transistor M10 is also connected to the source of N-channel MOS transistor M6. The source of N-channel MOS transistor M5 serves as the second input end of the loop selector. The drain of the N-channel MOS transistor M6 is connected to the drain of the N-channel MOS transistor M4. The drain of the N-channel MOS transistor M6 is also connected to the second input end of the energy consumption type equalization circuit. The drain of the N-channel MOS transistor M6 is also connected to the second input end of the flyback type equalization loop. Figure 3 In the example shown, the gate of each MOS tube is connected to the controller to be turned on or off under the control of the controller.

[0134] exist Figure 3In the large-capacity battery balancing circuit shown, two balancing loops based on energy-consuming elements such as resistors and flyback converters are constructed. The two balancing loops can be turned on by their respective balancing MOS tubes to achieve fine balancing of small currents and fast balancing of large currents, which is conducive to achieving the balancing purpose of large-capacity batteries. In addition to requiring accurate balancing, large-capacity batteries also require fast balancing speed. In addition, the two balancing loops are constructed by the same loop selector and selection array, that is, when the number of balanced batteries increases, only the selection array channels corresponding to the number of batteries need to be increased, and the loop selector can achieve balancing of the opposite polarity of the batteries connected to the loop with one balancing loop. Compared with other schemes, balancing loops can be saved, and the control is simple, and only the balancing MOS tube of the corresponding loop needs to be controlled to turn on the loop. That is, compared with the related schemes, the large-capacity battery balancing circuit adopted by the scheme of the present invention has high utilization rate of each device, good balancing effect that can be implemented, simple control, and lower cost.

[0135] The circuit selector selects the access mode of the battery to ensure the connection polarity between the battery and the balancing circuit. When balancing is to be turned on, the MOS tube in the selection array connected to the target battery cell is turned on, and the MOS tube in the commutator is turned on according to the polarity of the battery connection, so that the positive electrode of the battery cell is connected to the upper end of the balancing circuit in the figure, and the negative electrode of the battery cell is connected to the lower end of the balancing circuit in the figure, and the corresponding balancing circuit is turned on and controlled according to the battery charge. Specifically, the parameters of the flyback converter should be calculated according to the input voltage, output voltage, peak current and other requirements according to the design method of the converter. The MOS tube should be selected to meet the maximum stress voltage. The resistance value of resistor R1 is calculated according to the input voltage and the target balancing current, and the package that meets this power requirement is selected. If there is no package type that meets the power, the resistance value and power can be made up by connecting resistors in series and parallel. The primary current sampling module and the secondary current sampling module can be a sampling circuit or current sensor composed of a sampling resistor, an operational amplifier and other signal conditioning circuits.

[0136] Figure 4 FIG. 1 is a schematic diagram of a control system for a large-capacity battery balancing circuit according to an embodiment of the present invention. Figure 4 As shown, the control system of the large-capacity battery balancing circuit includes: a balancing current sampling module, a balancing module, a controller, a battery information acquisition module, a communication module and a storage module. The balancing current sampling module is connected to the balancing module. The controller is connected to the balancing module, the controller, the communication module and the storage module respectively.

[0137] Figure 3 The system implementing the equalization of the large-capacity battery equalization circuit shown in the figure may include the following: Figure 4The modules shown in the figure. Among them, the controller, the balancing module and the balancing current sampling module are the modules necessary for the implementation of the balancing action, the battery information acquisition module is the module required for the implementation of the balancing strategy, and the communication module and the storage module are optional modules. In this system, the controller can select any MCU (control unit) or DSP (digital signal processing unit) that meets the performance requirements. For example, the control chip model TMS320F28035 can be used as the controller. The main body of the balancing module is as follows Figure 3 The balancing circuit shown in the figure has the corresponding selection requirements in Figure 3 The example shown in the figure shows the balanced current sampling module. Figure 3 In the primary current sampling and secondary current sampling parts, the solution of the present invention uses a current acquisition circuit composed of a sampling resistor and an operational amplifier and other signal conditioning circuits to perform balanced current acquisition. The battery information acquisition module is used to obtain battery voltage, temperature and other information for obtaining balanced variables. In this embodiment, SOC is used as the balanced variable, such as using an AFE (analog front end) chip model LTC6811 and its application circuit as a battery information acquisition module to obtain battery voltage and temperature. In this embodiment, there are optional communication modules and storage modules. In this embodiment, the calculation of SOC is not Figure 4 The controller TMS320F28035 is used for calculation, but is sent to another main control chip for calculation through the communication module. The communication module of this embodiment can use a CAN (controller area network) communication chip such as a chip with a signal of TD501. In addition, this embodiment stores the SOC root mean square difference of the large current non-energy consumption type balancing start condition and the SOC root mean square difference of the small current energy consumption type balancing start condition, as well as other system parameters and fault information in the storage module. The storage chip used in this embodiment is a chip with a model of GT25C512.

[0138] The solution of the present invention is a balancing circuit including a flyback balancing circuit and a trickle balancing circuit, and a related balancing system and method. By performing flyback balancing on the battery when the difference in the battery state of charge is large, and using trickle balancing when the difference in the battery state of charge is small, a balancing process that meets the battery charging and discharging characteristics can be achieved, and the battery service life can be extended. In addition, trickle balancing is used at the end of balancing, and the balancing is stable and accurate, which can simultaneously achieve rapid balancing and accurate balancing of large-capacity batteries.

[0139] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned battery, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0140] By adopting the technical solution of this embodiment, a large-capacity battery balancing circuit is set by using a large-current balancing circuit based on a flyback type and a trickle balancing circuit based on an energy-consuming element. When the difference in the state of charge of the batteries is large, the large-current balancing circuit is used to perform large-current balancing on the batteries. When the difference in the state of charge of the batteries is small, the trickle balancing circuit is used to perform trickle balancing on the batteries. Battery balancing of large-capacity batteries is achieved with a fast balancing speed. The trickle balancing at the end of the balancing period has high precision, and repeated balancing is avoided.

[0141] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0142] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A battery balancing control device, characterized in that: The battery comprises: N battery cells, where N is a positive integer; the battery balancing circuit comprises: a flyback balancing unit and a trickle balancing unit; The battery balancing control device comprises: a sampling unit and a control unit; wherein, The sampling unit is configured to collect battery parameters of the battery; The control unit is configured to determine a balancing parameter of the battery according to a battery parameter of the battery; and When the balancing parameters of the battery meet the set flyback balancing start condition, the battery cells to be balanced in the battery are controlled to form a loop with the flyback balancing unit, so as to use the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery; When the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, control the battery cells to be balanced in the battery and the trickle balancing unit to form a loop, so as to use the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery; The battery balancing circuit further includes: a first selection unit; the first selection unit includes: N+1 selection branches; the battery balancing control device further includes: The control unit is further configured to determine the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an access instruction for accessing the battery cells to be balanced in the battery; The first selection unit is configured to, upon receiving the access instruction, connect the corresponding selection branch connected to the positive and negative electrodes of the battery cells to be balanced in the battery among the N+1 selection branches of the first selection unit itself, so as to connect the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit, and form a loop with the flyback balancing unit or the trickle balancing unit; The battery balancing circuit further includes: a second selection unit; the battery balancing control device further includes: The control unit is further configured to determine the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an opening instruction for a polarity selection branch in the selection unit; The second selection unit is configured to, upon receiving the opening instruction, open a polarity selection branch in the second selection unit to process the polarity of the battery cells to be balanced in the battery, so that the battery cells to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

2. The battery balancing control device according to claim 1, characterized in that: The balancing parameters of the battery include: any parameter of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of a root mean square difference, a maximum difference, and a mean value difference corresponding to any parameter of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

3. The battery balancing control device according to claim 1, characterized in that: The flyback balancing unit comprises: a flyback circuit; the flyback circuit comprises: a flyback converter, a first flyback switch tube module and a second flyback switch tube module; The first flyback switch tube module is arranged at the primary winding of the flyback converter; the second flyback switch tube module is arranged at the secondary winding of the flyback converter; The primary winding of the flyback converter can form a loop with the battery cells to be balanced in the battery; the secondary winding of the flyback converter can form a loop with the set storage battery.

4. The battery balancing control device according to claim 1, characterized in that: The trickle current balancing unit includes: an energy consumption balancing circuit; the energy consumption balancing circuit includes: a resistance module and an energy consumption switch tube module; wherein, The resistance module and the energy consumption switch tube module can form a loop with the battery cells to be balanced in the battery.

5. The battery balancing control device according to claim 1, characterized in that: Among the N battery cells, a positive electrode of each of the battery cells is connected to one of the N+1 selection branches, and a negative electrode of each of the battery cells is connected to another selection branch of the N+1 selection branches.

6. The battery balancing control device according to claim 5, characterized in that: In the N+1 selection branches, each selection branch includes: a first selection switch module and a second selection switch module; the first selection switch module and the second selection switch module are arranged in series.

7. The battery balancing control device according to any one of claims 1 to 6, characterized in that: The second selection unit includes: a first polarity selection branch and a second polarity selection branch.

8. The battery balancing control device according to claim 7, characterized in that: In the first polarity selection branch and the second polarity selection branch, each polarity selection branch includes: a first polarity selection switch tube module and a second polarity selection switch tube module; the first polarity selection switch tube module and the second polarity selection switch tube module are arranged in parallel.

9. A battery, characterized in that: include: A battery equalization control device according to any one of claims 1 to 8.

10. A battery balancing control method as claimed in claim 9, characterized in that: The battery comprises: N battery cells, where N is a positive integer; the battery balancing circuit comprises: a flyback balancing unit and a trickle balancing unit; The battery balancing control method comprises: collecting battery parameters of the battery; determining a balancing parameter of the battery according to a battery parameter of the battery; and, When the balancing parameters of the battery meet the set flyback balancing start condition, the battery cells to be balanced in the battery are controlled to form a loop with the flyback balancing unit, so as to use the flyback balancing unit to perform flyback balancing on the battery cells to be balanced in the battery; When the balancing parameters of the battery do not meet the set flyback balancing start-up conditions but meet the set trickle balancing start-up conditions, the battery cells to be balanced in the battery are controlled to form a loop with the trickle balancing unit, so as to use the trickle balancing unit to perform trickle balancing on the battery cells to be balanced in the battery.

11. The battery balancing control method according to claim 10, characterized in that: The balancing parameters of the battery include: any parameter of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery, and at least one of a root mean square difference, a maximum difference, and a mean value difference corresponding to any parameter of the battery state of charge of the battery, the remaining battery charge of the battery, and the battery voltage of the battery.

12. The battery balancing control method according to claim 10, characterized in that: The battery balancing circuit further includes: a first selection unit; the first selection unit includes: N+1 selection branches; among the N battery cells, the positive electrode of each of the battery cells is connected to one of the N+1 selection branches, and the negative electrode of each of the battery cells is connected to another selection branch of the N+1 selection branches; The battery balancing control method further includes: Determining a battery cell to be balanced in the battery according to the balancing parameters of the battery, and issuing an access instruction for accessing the battery cell to be balanced in the battery; When the access instruction is received by the first selection unit, the corresponding selection branches among the N+1 selection branches of the first selection unit itself, which are connected to the positive and negative electrodes of the battery cells to be balanced in the battery, are connected to connect the battery cells to be balanced in the battery to the flyback balancing unit or the trickle balancing unit to form a loop with the flyback balancing unit or the trickle balancing unit.

13. The battery balancing control method according to any one of claims 10 to 12, characterized in that: The battery balancing circuit further includes: a second selection unit; the second selection unit includes: a first polarity selection branch and a second polarity selection branch; The battery balancing control method further includes: Determine the polarity of the battery cells to be balanced in the battery according to the balancing parameters of the battery, and issue an opening instruction for a polarity selection branch in the selection unit; When the activation instruction is received by the second selection unit, a polarity selection branch in the second selection unit is activated to process the polarity of the battery cells to be balanced in the battery, so that the battery cells to be balanced in the battery and the flyback balancing unit or the trickle balancing unit form a loop, so that the battery cells to be balanced in the battery are balanced by the flyback balancing unit or the trickle balancing unit.

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