Active equalization circuit, battery management system, and active equalization control method

Abstract

An active equalization circuit, a battery management system, and an active equalization control method. The active equalization circuit comprises: a plurality of cascaded equalization modules, which are respectively sequentially connected to at least one group of batteries in a battery pack, and are used for controlling energy equalization between the at least one group of batteries; and an analog front-end sampling module, which uses a first port to sample the cell voltage of each battery cell, uses a second port to send the sampled cell voltage to a control unit and receive drive data provided by the control unit, and uses a third port to be communicatively connected to a first-stage equalization module among the plurality of cascaded equalization modules, transmit the drive data to the plurality of cascaded equalization modules by means of the first-stage equalization module, and control the plurality of equalization modules to perform active equalization.

Description

Active balancing circuit, battery management system and active balancing control method

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on June 21, 2024, with application number 202410812666.0, entitled “Active Balancing Circuit, Battery Management System and Active Balancing Control Method”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery management technology, and in particular to an active balancing circuit, a battery management system, and an active balancing control method. Background Technology

[0004] With the development of the new energy industry, battery systems are being used more widely in automobiles and energy storage. To increase battery capacity, the number of batteries connected in series and parallel is constantly increasing, leading to higher overall battery system voltage and higher requirements for the voltage withstand rating of isolation devices. The inconsistency in the voltage of individual cells within the battery system severely affects battery capacity. To address this, a balancing technology has been proposed. When the voltage of a cell is too low, energy from the connected power source is transferred to that cell; conversely, energy from a cell with an excessively high voltage is transferred to the power source. This achieves real-time balancing during charging and discharging, maximizing the potential of each cell. This ensures that each cell is fully charged during charging and discharged to its minimum discharge limit, maintaining the same voltage throughout the charging and discharging process. This allows each cell in the battery pack to reach its maximum capacity, effectively extending the lifespan of the entire battery pack.

[0005] However, the related balanced topology typically requires a large number of components, which is detrimental to the trend of product miniaturization and low cost. Furthermore, the failure rate of the entire battery control circuit board is relatively high during the manufacturing process. Therefore, it is necessary to provide improved technical solutions to overcome the technical problems existing in the related technologies. Summary of the Invention

[0006] According to various embodiments of this application, an active balancing circuit, a battery management system, and an active balancing control method are provided.

[0007] According to a first aspect of this application, an active equalization circuit is provided, comprising:

[0008] Multiple cascaded equalization modules are sequentially connected to at least one group of batteries in the battery pack, and are used to control the energy balance among the at least one group of batteries;

[0009] The analog front-end sampling module includes a first port, a second port, and a third port. The first port is connected to each individual cell in the battery pack and is used to sample the battery voltage of each individual cell. The second port is communicatively connected to the control unit and is used to send the sampled battery voltage to the control unit and receive drive data provided by the control unit. The third port is communicatively connected to the first-level equalization module in the cascaded plurality of equalization modules and is used to transmit the drive data to the cascaded plurality of equalization modules through the first-level equalization module and control the cascaded plurality of equalization modules to perform active equalization.

[0010] Optionally, each equalization module includes:

[0011] The first I connected to the previous level equalization module 2 The C port and the first enable port are used to implement the drive data transmission with the previous level equalization module;

[0012] The second I connected to the next level equalization module 2 Port C and the second enable port are used to implement the drive data transmission with the next-level equalization module;

[0013] The battery connection port is connected to the positive and negative terminals of at least one individual battery cell.

[0014] Among them, the first I of the first-level equalization module 2 The C port and the first enable port are connected to the analog front-end sampling module to realize the drive data transmission with the analog front-end sampling module.

[0015] Optionally, the drive data includes at least one of: enable data, address data, and drive control data.

[0016] Optionally, the drive control data includes at least one of: equalization on-direction configuration data and equalization current configuration data.

[0017] Optionally, the analog front-end sampling module and the first-level equalization module, as well as the two adjacent equalization modules, are connected via I... 2 C-bus communication connection.

[0018] Optionally, the driving data is transmitted between the analog front-end sampling module and the first-level equalization module, as well as between two adjacent equalization modules, using a relay method.

[0019] According to a second aspect of this application, a battery management system is provided, including an active balancing circuit as described in any embodiment of this application.

[0020] According to a third aspect of this application, an electric vehicle is provided, comprising: at least one set of batteries; and a battery management system as described in any embodiment of this application.

[0021] According to a fourth aspect of this application, an energy storage device is provided, comprising: at least one set of energy storage elements; and a battery management system as described in any embodiment of this application.

[0022] According to a fifth aspect of this application, an active equalization control method is provided, applied to an active equalization circuit as described in any embodiment of this application, the active equalization control method comprising:

[0023] The battery voltage of each individual cell is sampled and sent to the control unit;

[0024] Receive drive data provided by the control unit based on the sampled battery voltage;

[0025] The drive data is transmitted to multiple cascaded equalization modules using a daisy-chain communication method, and the multiple cascaded equalization modules are controlled to perform active equalization.

[0026] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the published drawings without creative effort.

[0028] Figure 1 shows a schematic diagram of one topology of the active balancing module.

[0029] Figure 2 shows a schematic diagram of the structure of a battery management system provided according to an embodiment of this application.

[0030] Figure 3 shows a flowchart of the active balancing control method provided according to an embodiment of this application. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0033] In the description of this application, words such as "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments. The term "and / or" in this document describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. "Multiple" refers to two or more. Furthermore, to facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0034] In addition, the same reference numerals in the figures indicate the same or similar structures, so repeated descriptions of them will be omitted. That is, the various parts in this specification are described in a combination of parallel and progressive manner. Each part focuses on the differences from other parts, and the same or similar parts between the various parts can be referred to each other.

[0035] In high-voltage applications, a large number of batteries or supercapacitors need to be connected in series. Voltage inconsistencies between individual batteries or supercapacitors can severely impact the system's usable capacity, creating a so-called "weakest link" effect. This can also lead to overcharging or over-discharging of individual batteries or supercapacitors, affecting system reliability. Active balancing technology, simply put, is about mitigating strengths and compensating for weaknesses. It uses specific techniques to transfer energy from batteries or supercapacitors with higher voltages to those with lower voltages, achieving real-time balance during charging and discharging. This maximizes the potential of each battery or supercapacitor and ensures that each battery or supercapacitor is fully charged and discharged simultaneously, extending system lifespan.

[0036] Figure 1 shows a schematic diagram of a topology for an active balancing module. As shown in Figure 1, this active balancing topology includes: an analog front-end sampling module (AFE) 110, an I / O expansion module 120, multiple optocoupler isolation devices 130, and multiple balancing modules (including balancing module 1 to balancing module n, where n is a positive integer greater than 1). Each balancing module is connected to at least one individual cell in the battery pack and is also connected to the I / O expansion module 120 through a corresponding optocoupler isolation device 130. The I / O expansion module 120 is also communicatively connected to the analog front-end sampling module (AFE) 110.

[0037] Its basic working process is as follows:

[0038] First, the analog front-end sampling module (AFE) 110 detects the voltage of each individual cell (hereinafter referred to as a cell) in the battery pack to determine which cells need to be balanced; then, the analog front-end sampling module (AFE) 110 uses I... 2 The C bus communicates with the I / O expansion module 120, sending equalization information to the I / O expansion module 120. This triggers the I / O expansion module 120 to output a high level on the I / O port of the equalization channel corresponding to the battery to be equalized, controlling the primary side of the corresponding optocoupler isolation device 130 to be turned on, thus enabling the enable pin of the corresponding equalization module. Finally, the enabled equalization module is used to complete the energy equalization operation of the battery to be equalized.

[0039] However, due to the topology of the active balancing module shown in Figure 1, I 2 The control operation of multiple equalization modules 1 to n can only be achieved by C expansion module 120, multiple resistors (including R1 to R2n) and multiple optocoupler isolation devices 130. The control part requires a large number of components, which not only makes the system cost higher, but also makes more components occupy a larger board area, which is not conducive to the miniaturization of the board size. At the same time, it will also increase the failure rate of the entire battery control circuit board.

[0040] To address the aforementioned issues, this application provides a cascaded topology for an active balancing module, which can be applied in the battery management system 200 shown in Figure 2. As shown in Figure 2, this cascaded topology for the active balancing module can use a daisy-chain communication method to control the balancing module, eliminating the need for additional I / O expansion chips and isolation devices. The number of components required for the circuit is reduced, thereby lowering the system cost and board area, and significantly reducing the failure rate of the entire battery control circuit board.

[0041] In the example shown in Figure 2, the battery management system 200 is connected to at least one group of batteries in the battery pack 240 for battery management, including energy balancing, of the connected battery pack 240. For example, in some embodiments, the battery management system 200 can also monitor parameters such as voltage / current and temperature of the battery pack 240 during charging / discharging and provide charging / discharging protection.

[0042] The battery pack 240 includes multiple individual cells V1 to Vm connected in series, where m is a positive integer greater than 1. In some other examples, the battery pack 240 may also be replaced by an energy storage module consisting of multiple supercapacitors or other energy storage elements.

[0043] The battery management system 200 includes an active balancing circuit and a control unit 210 connected to the active balancing circuit. In some other examples, the control unit 210 may also be included within the active balancing circuit.

[0044] Optionally, the control unit 210 may be any one of a microcontroller unit (MCU), a digital signal processor (DSP), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). In this embodiment, it may be a microcontroller unit (MCU), but this is not intended to limit the embodiments of this application. In other embodiments, it may be replaced by the above or other devices or components capable of performing digital signal control.

[0045] The active equalization circuit further includes: multiple cascaded equalization modules 231 to 23n, and an analog front-end sampling module (AFE) 220, where n is a positive integer greater than 1.

[0046] Multiple cascaded equalization modules 231-23n are sequentially connected to at least one group of batteries in the battery pack 240 to control the energy balance among the at least one group of batteries. In this embodiment, the solution of this application will be described only by taking the connection of multiple cascaded equalization modules 231-23n to multiple series-connected individual batteries V1-Vm as an example.

[0047] Optionally, the topology of the basic unit (or module) within each equalization module can be selected from non-isolated Boost, Buck, and Boost-Buck converter circuits, or from bidirectional isolated DC / DC converter circuits or other flyback topologies. Depending on the applicable scenario and system requirements, other components or modules readily conceived by those skilled in the art can be flexibly adjusted or replaced, without limitation.

[0048] The analog front-end sampling module (AFE) 220 includes a first port (not shown), a second port (not shown), and a third port (not shown). The first port is connected to each individual cell in the battery pack 240 (e.g., connected to multiple nodes C20 to C2m of the battery pack 240) to sample the battery voltage of each individual cell (e.g., V1 = C21 - C20, V2 = C22 - C21, ..., Vm = C2m - C2(m-1)). The second port is communicatively connected to the control unit 210 to send the sampled battery voltage to the control unit 210 and to receive drive data provided by the control unit 210. The third port is communicatively connected to the first-stage equalization module 231 of the cascaded equalization modules to transmit drive data to the cascaded equalization modules through the first-stage equalization module 231 and to control the cascaded equalization modules to perform active equalization.

[0049] Optionally, the second port of the analog front-end sampling module (AFE) 220 is connected to the control unit 210, and the third port of the analog front-end sampling module (AFE) 220 is connected to the first-stage equalization module 231 via I / O. 2 Data communication is performed via the C-bus or other communication protocols. Furthermore, the first, second, and third ports of the analog front-end sampling module (AFE) 220 can be implemented, for example, by at least one GPIO (general purpose input / output) pin.

[0050] In this embodiment, each equalization module includes: a first I 2 Port C (including the first clock port DSCL and the first data port DSDA), the first enable port DEN, and the second I... 2 Port C (including the second clock port USCL and the second data port USDA), the second enable port UEN, and the battery connection port. Among these, the first I... 2 Port C and the first enable port DEN are respectively connected to the second I of the previous level equalization module. 2 The C port and the second enable port UEN are connected to enable drive data transmission with the previous level equalization module; the second I... 2 Port C and the second enable port UEN are respectively connected to the first I of the next-level equalization module. 2The C port and the first enable port DEN are connected to enable drive data transmission with the next-level equalization module; the battery connection port is connected to the positive and negative terminals of at least one individual battery cell. That is to say, in these examples, adjacent equalization modules communicate via I... 2 C bus communication connection, thereby through I 2 Data communication is performed using the C-bus protocol. Of course, in other embodiments, adjacent equalization modules or multiple cascaded equalization modules can also be connected and cascaded through other conventional communication interfaces.

[0051] It should be noted that in a cascaded series of equalization modules, the first I of the first-level equalization module... 2 The C port and the first enable port DEN are connected to the second port of the analog front-end sampling module 220 to enable drive data transmission with the analog front-end sampling module 220; and the second I port of the last stage equalization module 23n 2 Port C and the second enable port UEN are not connected.

[0052] In the example shown in Figure 2, the battery connection ports include a first connection port VP, a second connection port VM, and a third connection port GND. In this case, each equalization module can be simultaneously connected to the positive and negative terminals of two adjacent individual cells through the battery connection ports. Of course, other implementations are also possible. For example, in other embodiments of this application, the battery connection ports may include a greater number of connection ports, thereby enabling simultaneous connection to three or more adjacent individual cells. This application does not impose strict limitations on this.

[0053] Furthermore, the analog front-end sampling module 220 and the first-stage equalization module 231, as well as adjacent equalization modules, use a relay method to transmit drive data. This ensures that the communication waveform does not attenuate as the number of equalization modules increases, guaranteeing the accuracy and reliability of drive data transmission during cascaded communication.

[0054] In this embodiment, the drive data includes at least one of: enable data, address data, and drive control data. Enable data is transmitted through a corresponding enable port, while address data and drive control data are transmitted through corresponding I / O ports. 2 Transmission is handled via port C. Enable data controls the data transmission of each equalizer module; when enable data is active, the equalizer module is powered on and can receive drive data from the upstream equalizer module and transmit it to the downstream equalizer module. Address data is used to locate the equalizer module; based on the address data, drive control data can be transmitted to the specific equalizer module. Drive control data is used to control the equalizer module to perform active equalization operations.

[0055] In some optional examples, the drive control data further includes at least one of: equalization activation direction configuration data and equalization current configuration data. In this embodiment, the equalization activation direction (e.g., buck or boost) and equalization current magnitude of the equalization module during active equalization can be easily determined via I... 2 The C-communication configuration allows the active equalization circuit to be adapted to different application scenarios.

[0056] In this embodiment, the basic working process of the active equalization circuit is as follows:

[0057] The analog front-end sampling module (AFE) 220 collects the voltage of each individual cell (hereinafter referred to as a cell) in the battery pack 240 and sends the collected cell voltage to the control unit 210. The control unit 210 determines which cells need to be balanced based on the voltage of each individual cell, generates corresponding drive data, and transmits it to the analog front-end sampling module (AFE) 220. The analog front-end sampling module (AFE) 220 then uses I... 2 The C-bus communicates with the first-level equalization module 231 to transmit drive data to multiple cascaded equalization modules. This includes first enabling the multiple cascaded equalization modules according to the enable data in the drive data, and then using a daisy-chain communication method to transmit the drive control data through a relay to one or more equalization modules that need to perform active equalization operations according to the address data in the drive data. The equalization module is then controlled to complete the energy or charge equalization of the individual cells to be equalized according to the drive control data in the drive data.

[0058] It is understood that the active balancing schemes provided in the embodiments of this application adopt a cascaded communication topology to set up multiple balancing modules connected to at least one group of batteries. This allows the multiple cascaded balancing modules to communicate data in a daisy-chain manner during active balancing control. Therefore, compared with the traditional topology, the active balancing circuits provided in the embodiments of this application do not require additional I / O expansion chips, reducing the workload of software and requiring fewer components, which can reduce the cost and board area of ​​the system, and the failure rate of the entire battery control circuit board is low.

[0059] Furthermore, one embodiment of this application also provides an electric vehicle, including: at least one set of batteries (or supercapacitors), and a battery management system 200 as disclosed in any of the foregoing embodiments.

[0060] Furthermore, another embodiment of this application provides an energy storage device, including: at least one set of energy storage elements (such as batteries or supercapacitors), and a battery management system 200 as disclosed in any of the foregoing embodiments.

[0061] By installing the aforementioned battery management system 200 in electric vehicles, energy storage devices, and other equipment, real-time balancing during charging and discharging can be fully realized, maximizing the potential of each battery cell. This ensures that each battery cell is fully charged during charging and discharged to its minimum limit during discharging, while maintaining the same voltage throughout the charging and discharging process. This allows the capacity of each battery cell in the battery pack to be fully utilized, thus effectively extending the lifespan of the entire battery pack.

[0062] Furthermore, one embodiment of this application also discloses an active balancing control method, which can be applied to the active balancing circuit or battery management system disclosed in any of the foregoing embodiments. In specific implementation, as shown in FIG3, the active balancing control method includes performing the following steps:

[0063] Step 310: Sample the battery voltage of each individual cell and send the sampled battery voltage to the control unit.

[0064] Step 320: Receive drive data provided by the control unit based on the sampled battery voltage.

[0065] Step 330: The drive data is transmitted to multiple cascaded equalization modules using a daisy-chain communication method, and the multiple cascaded equalization modules are controlled to perform active equalization.

[0066] In practice, the specific implementation of each step in the active balancing control method described above and the beneficial effects it can bring can be found in the aforementioned embodiments of the active balancing circuit or battery management system, and will not be repeated here.

[0067] It should be noted that all the modules and units mentioned above can be implemented through hardware devices, including corresponding circuits or components.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An active equalization circuit, characterized in that, include: Multiple cascaded equalization modules are sequentially connected to at least one group of batteries in the battery pack, and are used to control the energy balance among the at least one group of batteries; The analog front-end sampling module includes a first port, a second port, and a third port. The first port is connected to each individual cell in the battery pack and is used to sample the battery voltage of each individual cell. The second port is communicatively connected to the control unit and is used to send the sampled battery voltage to the control unit and receive drive data provided by the control unit. The third port is communicatively connected to the first-level equalization module among the cascaded equalization modules, and is used to transmit the driving data to the cascaded equalization modules through the first-level equalization module, and control the cascaded equalization modules to perform active equalization.

2. The active equalization circuit according to claim 1, wherein, Each equalization module includes: The first I connected to the previous level equalization module 2 The C port and the first enable port are used to implement the drive data transmission with the previous level equalization module; The second I connected to the next level equalization module 2 Port C and the second enable port are used to implement the drive data transmission with the next-level equalization module; The battery connection port is connected to the positive and negative terminals of at least one individual battery cell. Among them, the first I of the first-level equalization module 2 The C port and the first enable port are connected to the analog front-end sampling module to realize the drive data transmission with the analog front-end sampling module.

3. The active equalization circuit according to claim 1 or 2, wherein, The drive data includes at least one of the following: enable data, address data, and drive control data.

4. The active equalization circuit according to claim 3, wherein, The drive control data includes at least one of the following: equalization activation direction configuration data and equalization current configuration data.

5. The active equalization circuit according to claim 1, wherein, The analog front-end sampling module and the first-level equalization module, as well as the two adjacent equalization modules, are connected via I... 2 C-bus communication connection.

6. The active equalization circuit according to claim 1, wherein, The driving data is transmitted between the analog front-end sampling module and the first-level equalization module, as well as between the two adjacent equalization modules, using a relay method.

7. A battery management system, characterized in that, include: The active equalization circuit as described in any one of claims 1-6.

8. An electric vehicle, characterized in that, include: At least one set of batteries; The battery management system as described in claim 7.

9. An energy storage device, characterized in that, include: At least one set of energy storage elements; The battery management system as described in claim 7.

10. An active equalization control method, applied to the active equalization circuit as described in any one of claims 1-6, characterized in that, The active balancing control method includes: The battery voltage of each individual cell is sampled and sent to the control unit; Receive drive data provided by the control unit based on the sampled battery voltage; The drive data is transmitted to multiple cascaded equalization modules using a daisy-chain communication method, and the multiple cascaded equalization modules are controlled to perform active equalization.

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