CN-121984167-A - Battery equalization circuit, battery equalization method and energy storage system

CN121984167ACN 121984167 ACN121984167 ACN 121984167ACN-121984167-A

Abstract

The application relates to a battery equalization circuit, a battery equalization method and an energy storage system. The battery cell control unit of the circuit is used for collecting battery cell state parameters of a plurality of battery cells and executing charge and discharge control, the electric quantity balance conversion loop is used for carrying out energy transfer among different battery cells, the micro control unit is used for receiving the battery cell state parameters collected by the battery cell control unit and generating corresponding energy balance control instructions, the analog front end switching unit is used for responding to the energy balance control instructions and switching current paths among different battery cells through corresponding optocoupler control channels so as to balance the energy of the battery cells, the technical problems that the cost is high and the circuit is complex due to the fact that a large number of control chips, power devices and magnetic elements are used in an active balancing scheme of a high-serial number energy storage system are solved, the number of control chips, power devices and magnetic elements required is reduced, and the technical effects of remarkably reducing the hardware cost and the circuit complexity of active balancing of the high-serial number battery system are achieved.

Inventors

TANG SHUANGXI
RONG ZHOU
Shang Huimei
Weng Chuxuan

Assignees

浙江卧龙储能系统有限公司

Dates

Publication Date: 20260505
Application Date: 20251215

Claims (11)

1. A battery equalization circuit, comprising: The battery cell control unit is used for collecting battery cell state parameters of a plurality of battery cells and executing charge and discharge control, and the battery cells comprise a plurality of battery cells connected in series; the electric quantity balance conversion circuit is used for transferring energy among different battery units; the micro control unit is used for receiving the battery core state parameters acquired by the battery core control unit, generating corresponding energy balance control instructions and sending the corresponding energy balance control instructions to the analog front-end switching unit; The analog front-end switching unit is arranged between the battery cell control unit and the electric quantity balance conversion loop and is used for responding to the energy balance control instruction and switching current paths among different battery units through corresponding optocoupler control channels so as to balance the energy of the battery units.
2. The battery equalization circuit of claim 1, wherein the analog front-end switching unit comprises at least one analog front-end switching sub-unit, each of the analog front-end switching sub-units being correspondingly connected to one of the optocoupler control channels.
3. The battery equalization circuit of claim 1, further comprising a digital isolation unit disposed between the micro control unit and the analog front end switching unit for achieving electrical isolation and signal transmission.
4. The battery equalization circuit of claim 1, further comprising a first control unit and a second control unit, wherein the micro control unit is further configured to select an analog front-end switching unit, and control the first control unit to work cooperatively with the second control unit, and turn on an optocoupler control channel of a corresponding battery unit in the selected analog front-end switching unit.
5. The battery equalization circuit of claim 4, wherein the cell control unit monitors and equalizes cell state parameters of the battery cells through the first control unit, and the first control unit is correspondingly connected with different battery cells through a plurality of optocoupler control channels.
6. The battery equalization circuit of claim 4, wherein a single optocoupler control channel of the first control unit simultaneously controls multiple groups of switching tubes, each corresponding to a same serial number cell in multiple different analog front-end switching units.
7. The battery equalization circuit of claim 4, wherein the charge equalization conversion loop controls energy transfer from a high-power cell to a low-power cell via the second control unit.
8. The battery equalization circuit of claim 4, wherein said micro control unit is further configured to switch the power supply of said analog front end switching unit and the ground reference synchronously so that the operating voltage of said second control unit does not exceed the maximum withstand voltage threshold value before equalization is performed.
9. The battery equalization circuit of any of claims 1-8, wherein the energy transfer process comprises: In the BUCK stage, a 12V power supply discharges to the ground through an inductor, and the inductor stores energy; in the follow current stage, the inductor releases energy through an electric quantity balance conversion loop corresponding to the low-power battery cell, and the low-power battery cell is charged.
10. A battery equalization method applied to the battery equalization circuit according to any one of claims 1 to 9, characterized in that the battery equalization method comprises: The micro-control unit collects the state parameters of the battery cells of each battery cell; judging whether a battery cell with the battery cell state parameter deviation exceeding a preset threshold value exists or not; If yes, the micro control unit sends an energy balance control instruction to the corresponding analog front end switching unit; The analog front end switching unit switches corresponding optocoupler control channels according to the energy balance control instruction, and a current path is established; the electric quantity balance conversion loop is started to transfer surplus energy from the high-electric-quantity battery cell to the low-electric-quantity battery cell; when the state parameter deviation of the battery core tends to balance, the micro control unit closes the optical coupler control channel to finish one-time balancing operation.
11. An energy storage system comprising a battery equalization circuit as claimed in any one of claims 1 to 9.

Description

Battery equalization circuit, battery equalization method and energy storage system Technical Field The application relates to the technical field of energy storage of electrochemical devices, in particular to a battery equalization circuit, a battery equalization method and an energy storage system. Background With the improvement of the capacity and voltage requirements of the battery pack by the application of electric vehicles, energy storage systems and the like, the number of series batteries is increased, the problems caused by monomer differences are increasingly serious, the traditional resistance energy consumption type equalization efficiency is low, and the requirements of a high-energy-density battery system cannot be met. The active equalization technology of the energy storage system is a key component in a Battery management system (Battery MANAGEMENT SYSTEM, BMS) and is mainly used for solving the problem of inconsistency among single cells in a Battery pack. The core idea is to transfer the energy of the monomer battery with higher electric quantity to the monomer battery with lower electric quantity in an active energy transfer mode, so as to realize the dynamic balance of the energy in the battery pack. The existing mainstream active equalization technology based on inductance energy storage needs a large number of control chips, power devices and magnetic elements, and has the problems of high difficulty in circuit layout of high-string-number battery packs, large number of control chips and high cost. In view of the above problems, no effective solution has been proposed at present. Disclosure of Invention The embodiment of the application provides a battery equalization circuit, a battery equalization method and an energy storage system, which at least solve the technical problems of high cost and complex circuit caused by the use of a large number of control chips, power devices and magnetic elements in an active equalization scheme of a high-serial-number energy storage system. According to one aspect of the embodiment of the application, a battery equalization circuit is provided, which comprises a battery cell control unit, an electric quantity equalization conversion loop, a micro control unit (Microcontroller Unit, MCU) and an Analog Front End (AFE) switching unit, wherein the battery cell control unit is used for collecting battery cell state parameters of a plurality of battery cells and executing charge and discharge control, the battery cells comprise a plurality of battery cells connected in series, the electric quantity equalization conversion loop is used for carrying out energy transfer among different battery cells, the micro control unit (Microcontroller Unit, MCU) is used for receiving the battery cell state parameters collected by the battery cell control unit and generating corresponding energy equalization control instructions to send to the Analog Front End (AFE) switching unit, and the Analog Front End switching unit is arranged between the battery cell control unit and the electric quantity equalization conversion loop and used for switching current paths among different battery cells through corresponding optocoupler control channels in response to the energy equalization control instructions. Optionally, the analog front end switching unit includes at least one analog front end switching subunit, and each analog front end switching subunit is correspondingly connected to one optical coupler control channel. Optionally, the device further comprises a digital isolation unit, which is arranged between the micro control unit and the analog front end switching unit and is used for realizing electrical isolation and signal transmission. Optionally, the system further comprises a first control unit and a second control unit, wherein the micro control unit is further used for selecting an analog front end switching unit and controlling the first control unit and the second control unit to work cooperatively, and an optocoupler control channel of a corresponding battery unit in the selected analog front end switching unit is opened. Optionally, the battery cell control unit monitors and equalizes the battery cell state parameters of the battery cells through the first control unit, and the first control unit is correspondingly connected with different battery cells through a plurality of optocoupler control channels respectively. Optionally, a single optocoupler control channel of the first control unit simultaneously controls multiple groups of switching tubes, and the multiple groups of switching tubes respectively correspond to the same serial number battery cells in multiple different analog front-end switching units. Optionally, the electric quantity balancing conversion loop controls energy transfer from the high-electric-quantity battery cell to the low-electric-quantity battery cell through the second control unit. Optionally, the micro control unit is further