Lithium battery constant-current constant-voltage type active equalization device and lithium battery constant-current constant-voltage type active equalization method

Abstract

The invention discloses a constant-current constant-voltage active equalization device and method for a lithium battery, and the device comprises an active equalization constant-current constant-voltage power module which is used for charging a single battery cell with a constant current when the voltage of the single battery cell is lower than a constant voltage; when the voltage of the single battery cell reaches a constant voltage, the single battery cell is charged by the constant voltage; the battery cell voltage data acquisition module is used for acquiring voltage data of single battery cells in the battery cell group; the cell selection matrix switch module comprises an optical isolation solid-state relay; and the battery cell equalization control module is used for reading the voltage data of the battery cell voltage data acquisition module and controlling the battery cell selection matrix switch module and the active equalization constant-current constant-voltage power supply module according to the voltage data, so that the active equalization constant-current constant-voltage power supply module realizes charging equalization of the battery cell monomers in the battery cell group. When the voltage difference of the battery cells is large and the battery pack is actively balanced, the data acquisition of the AFE chip at the front end of the BMS is not influenced.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to a constant current and constant voltage active balancing device and method for lithium batteries. Background Technology

[0002] Lithium-ion battery balancing technology plays a crucial role in electric vehicles, energy storage systems, and other fields. Due to differences in cell consistency and the peripheral circuitry of each cell, the static power consumption of each cell is inconsistent. As usage time increases, these differences between cells become more pronounced, affecting battery lifespan and overall lifespan.

[0003] To reduce the impact of inconsistencies within lithium batteries on battery pack performance, battery balancing is necessary. Currently, battery balancing is divided into two types: passive balancing and active balancing.

[0004] The advantages of passive balancing are its simple circuit structure and low cost; the disadvantages are low energy utilization and increased heat dissipation of the module. During charging, passive balancing controls a small-current discharge circuit to discharge the overvoltage cells in the battery pack, delaying the overcharge protection time and allowing the low-voltage cells in the battery pack to charge, ensuring all cells in the battery pack are fully charged. Because this balancing method involves passive energy consumption, it is called passive balancing.

[0005] The advantages of active balancing are fast balancing speed and high energy utilization; the disadvantages are more complex circuitry and higher cost. Active balancing achieves energy transfer balancing by transferring energy from high-energy cells to low-energy cells, or by using the energy of the entire battery pack to charge low-energy cells, thereby reducing the energy gap between cells and ultimately achieving a balanced state. Because it is an active energy transfer process, it is called active balancing.

[0006] Current active balancing circuit designs for lithium-ion battery packs primarily employ capacitor, inductor, and transformer methods. All these balancing methods utilize pulsed charging and discharging for energy transfer. When the cell voltage difference is large, the operating current is high; when the cell voltage difference is small, the operating current is low. When the cell voltage difference is large, the high operating current during active balancing of the battery pack can affect the data acquisition of the AFE (Analog Front End) chip in the BMS (Battery Management System), causing fluctuations in the acquired cell voltage.

[0007] Therefore, there is an urgent need to develop a constant current and constant voltage active balancing device for lithium batteries to solve the problem of affecting the data acquisition of the BMS front-end AFE chip when the cell voltage difference is large and the battery pack is actively balanced. Summary of the Invention

[0008] In view of the above problems, the present invention provides a constant current and constant voltage active balancing device and method for lithium batteries.

[0009] The technical solution adopted by this invention to solve the technical problem is as follows: In a first aspect, the present invention provides a lithium battery constant current and constant voltage active balancing device, comprising: An active balancing constant current and constant voltage power supply module is used to charge a single battery cell with a constant current when the voltage of the single battery cell is lower than the constant voltage of the active balancing constant current and constant voltage power supply module; and to charge the single battery cell with the constant voltage when the voltage of the single battery cell reaches the constant voltage of the active balancing constant current and constant voltage power supply module. The cell voltage data acquisition module is used to collect the voltage data of individual cells in the cell group; The cell selection matrix switch module includes several optically isolated solid-state relays; The cell balancing control module is used to read the voltage data from the cell voltage data acquisition module, and based on this, controls the cell selection matrix switch module and the active balancing constant current and constant voltage power supply module to enable the active balancing constant current and constant voltage power supply module to achieve charging balancing of individual cells in the cell group.

[0010] In a preferred embodiment, the active balancing constant current and constant voltage power supply module, the cell voltage data acquisition module, and the cell selection matrix switch module are all connected to individual cells in the cell group, and the cell balancing control module is connected to the cell voltage data acquisition module, the cell selection matrix switch module, and the active balancing constant current and constant voltage power supply module.

[0011] In a preferred embodiment, the cell balancing control module includes an MCU power supply and an MCU module. The MCU power supply is used to power the MCU module, and the MCU module is used to read the voltage data from the cell voltage data acquisition module, and thereby control the cell selection matrix switch module to enable the active balancing constant current and constant voltage power supply module to achieve charging balancing of individual cells in the cell group.

[0012] In a preferred embodiment, the MCU module includes a voltage input pin, a ground pin, an enable pin, a clock signal pin, a chip select enable pin, a master input / slave output pin, a master output / slave input pin, several digital switch input channels, and multiple digital switch input pins. The input pins of the MCU module are connected to the MCU power supply. The clock signal pin, chip select enable pin, master input / slave output pin, and master output / slave input pin of the MCU module are all connected to the cell voltage data acquisition module. The enable pin of the MCU module is connected to the active equalization constant current / constant voltage power supply module.

[0013] In a preferred embodiment, the cell selection matrix switch module includes a first switch unit, a second switch unit, and multiple third switch units; the first switch unit, the second switch unit, and the third switch units are all optically isolated solid-state relays; the first switch unit is connected to the active balancing constant current and constant voltage power supply module, the third switch unit, and the cell balancing control module; the second switch unit is connected to the cell balancing control module and the third switch unit; the number of digital switch input pins is the same as that of the third switch units, and the digital switch input pins are connected one-to-one with the third switch units; the third switch unit is connected to a single cell.

[0014] In a preferred embodiment, the first switch unit, the second switch unit, and the third switch unit each include a voltage input pin, an output pin, and an enable pin. The first switch unit and the second switch unit are each connected to the digital switch input channel through their own enable pins, and the enable pin of the third switch unit is connected to the digital switch input pin.

[0015] In a preferred embodiment, the active equalization constant current and constant voltage power supply module includes a switching power supply chip, a DC / DC isolated power supply module, and a charging management chip connected in sequence, wherein the charging management chip is connected to the voltage input pin of the first switching unit.

[0016] In a preferred embodiment, the cell voltage data acquisition module includes a clock signal pin, a chip select enable pin, a master input / slave output pin, a master output / slave input pin, and multiple pins for acquiring individual cell voltages.

[0017] In a preferred embodiment, the cell balancing control module is used to control the switching of the active balancing constant current and constant voltage power supply module according to the voltage data.

[0018] Secondly, the present invention provides an active balancing method for the aforementioned lithium battery constant current constant voltage active balancing device, comprising: Based on the assessment, it can be determined whether any individual battery cells require balancing; If equalization is required, the cell equalization control module turns on the active equalization constant current and constant voltage power supply module through the DC_EN signal. The active equalization constant current and constant voltage power supply module outputs power. The first switch unit and the second switch unit corresponding to the cell that needs to be equalized are both turned on. The digital switch input pin corresponding to the cell that needs to be equalized is turned on. The cell selection matrix switch module selects the cell that needs to be equalized for equalization.

[0019] This invention utilizes an active balancing constant current and constant voltage power supply module, a cell voltage data acquisition module, a cell selection matrix switch module, and a cell balancing control module to achieve the following: when the voltage of a single cell is lower than the constant voltage of the active balancing constant current and constant voltage power supply module, the single cell is charged with a constant current; when the voltage of a single cell reaches the constant voltage of the active balancing constant current and constant voltage power supply module, the single cell is charged with the constant voltage. Even when the cell voltage difference is large and active balancing of the battery pack is being performed, the data acquisition of the BMS front-end AFE chip is not affected. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The diagram shows the structure and connection relationship of the active balancing device provided by the present invention. Figure 2 A schematic diagram of the active balancing constant current and constant voltage power supply module of the active balancing device provided by the present invention; Figure 3 A schematic diagram of the cell voltage data acquisition module of the active balancing device provided by the present invention; Figure 4 A schematic diagram of the cell balancing control module of the active balancing device provided by the present invention; Figure 5 A schematic diagram of the cell selection matrix switch module of the active balancing device provided by the present invention. Detailed Implementation

[0022] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0024] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0025] See Figure 1 In this embodiment, a lithium battery constant current and constant voltage active balancing device is provided, including: an active balancing constant current and constant voltage power supply module, a cell voltage data acquisition module, a cell selection matrix switch module, and a cell balancing control module; An active balancing constant current and constant voltage power supply module is used to charge a single battery cell with a constant current when the voltage of the single battery cell is lower than the constant voltage of the active balancing constant current and constant voltage power supply module; and to charge the single battery cell with the constant voltage when the voltage of the single battery cell reaches the constant voltage of the active balancing constant current and constant voltage power supply module. The cell voltage data acquisition module is used to collect the voltage data of individual cells in the cell group; The cell selection matrix switch module includes several optically isolated solid-state relays; The cell balancing control module is used to read the voltage data from the cell voltage data acquisition module, and based on this, controls the cell selection matrix switch module and the active balancing constant current and constant voltage power supply module to enable the active balancing constant current and constant voltage power supply module to achieve charging balancing of individual cells in the cell group.

[0026] Understandably, the active balancing constant current and constant voltage power supply module is used for charging balancing of individual cells in the battery pack. Charging balancing corresponds to the function of the active balancing constant current and constant voltage power supply module. Specifically, when the voltage of a single cell is lower than the constant voltage, it charges the cell with a constant current; when the voltage of a single cell reaches the constant voltage, it charges the cell with a constant voltage. The constant voltage of the active balancing constant current and constant voltage power supply module can be understood as a preset constant voltage, and the constant current can be understood as a preset constant current.

[0027] Please see Figure 1The active balancing constant current and constant voltage power supply module, the cell voltage data acquisition module, and the cell selection matrix switch module are all connected to individual cells in the cell group. The cell balancing control module is connected to the cell voltage data acquisition module, the cell selection matrix switch module, and the active balancing constant current and constant voltage power supply module. The cell balancing control module achieves charging balancing of individual cells in the cell group by controlling the active balancing constant current and constant voltage power supply module and the cell selection matrix switch module (i.e., providing signals to the active balancing constant current and constant voltage power supply module and signals to the cell selection matrix switch module).

[0028] In this embodiment, the cell balancing control module is used to control the switching of the active balancing constant current and constant voltage power supply module.

[0029] The active balancing constant current and constant voltage power supply module is a power supply module that can charge individual cells in a battery pack with constant current and constant voltage. The module outputs a voltage of 3.65V and a current of 1A. When the module is charging individual cells, if the cell voltage is lower than 3.65V, it charges the cell with a constant current of 1A; if the cell voltage reaches 3.65V, it charges the cell with a constant voltage of 3.65V.

[0030] See Figure 2 The active balancing constant current and constant voltage power supply module consists of: a switching power supply chip, a DC / DC isolated power supply module, and a charging management chip. It also includes external components such as resistors, capacitors, and inductors.

[0031] The switching power supply chip is used for voltage conversion and regulation, electrical isolation, and safety protection. The DC / DC isolated power supply module is a key component for achieving electrical isolation between high and low voltage circuits. The charging management chip is used for power path management, intelligently controlling the connection between the charging power supply and the battery to optimize charging efficiency; it is also used for charge and discharge control, precisely controlling the charging current and voltage based on the battery status (such as voltage, current, and temperature) to ensure that the battery is charged within a safe range; the charging management chip also integrates overcharge, over-discharge, overcurrent, and short-circuit protection mechanisms to prevent battery damage due to abnormal charging.

[0032] The switching power supply chip includes a voltage input pin (VIN), a ground pin (GND), an enable pin (EN), and a voltage output pin (VOUT).

[0033] The DC / DC isolated power supply module includes a voltage input pin (VIN), a ground pin (GND), a voltage output pin (VOUT), and an output signal reference ground (OUT_GND).

[0034] The DC / DC isolated power supply module is used to convert a 12V input to a 9V output.

[0035] The charging management chip, as a constant current and constant voltage charging module, includes a voltage input pin (VIN), a ground pin (GND), and a voltage output pin (VOUT).

[0036] The voltage output pin (VOUT) of the charging management chip outputs a constant voltage of 3.65V.

[0037] The voltage output pin of the switching power supply chip is connected to the voltage input pin of the DC / DC isolated power supply module. The voltage output pin of the DC / DC isolated power supply module is connected to the voltage input pin of the charging management chip. The voltage output pin of the charging management chip is connected to the cell selection matrix switch module. The voltage input pin of the switching power supply chip is connected to BAT+, and BAT- is connected to the ground pin of the switching power supply chip. External power is connected to the switching power supply chip through its own BAT+ and BAT- pins. The ground pin of the switching power supply chip, BAT-, and the ground pin of the DC / DC isolated power supply module are all grounded. The output signal reference ground of the DC / DC isolated power supply module and the voltage output pin of the charging management chip are both connected to ISO_BAT-, which serves as the negative terminal reference point for battery pack voltage detection.

[0038] The cell voltage data acquisition module is used to collect voltage data from multiple individual cells in the battery pack. It has multiple cell voltage acquisition channels and can convert and store the voltage of individual cells in the battery pack for use by the cell balancing control module.

[0039] See Figure 3 The cell voltage data acquisition module includes a voltage input pin (VIN) and a ground pin (GND). It also includes several pins for cell voltage acquisition, such as: BAT0, BAT1, BAT2, BAT3, BAT4, BAT5, BAT6, BAT7, BAT8, BAT9, BAT10, BAT11, BAT12, BAT13, BAT14, BAT15, and BAT16. The number of pins for cell voltage acquisition is the same as the number of pins in the third switching unit described below, and they are connected in a one-to-one correspondence. Each pin (BAT0 to BAT16) is connected to an output pin (OUT) of the third switching unit described below. The cell voltage data acquisition module also includes SPI1_CLK (clock signal pin), SPI1_CSN (chip select enable pin), SPI1_MISO (master input, slave output pin), and SPI1_MISI (master output, slave input pin), all used to connect to the cell equalization control module. The voltage input pin (VIN) is connected to the external power supply's BAT+, and the ground pin (GND) is connected to the external power supply's BAT-.

[0040] See Figure 4 The cell balancing control module includes an MCU power supply and an MCU module. The core component of the cell balancing control module is the MCU module. The MCU module obtains the voltage data in the battery pack by reading the data from the cell voltage data acquisition module. Based on the voltage data in the battery pack, it controls the active balancing constant current and constant voltage power supply module and the cell selection matrix switch module to balance the low-voltage cells in the cell pack.

[0041] The MCU power supply includes a voltage input pin (VIN), an output pin (OUT), and a ground pin (GND). The MCU module includes a voltage input pin (VIN), a ground pin (GND), an enable pin (DC_EN), an SPI1_CLK pin (clock signal pin), an SPI1_CSN pin (chip select enable pin), an SPI1_MISO pin (master input / slave output pin), an SPI1_MISI pin (master output / slave input pin), several digital switch input channels, and multiple digital switch input pins. Specifically, these include SW_1 pin (digital switch input channel one), SW_2 pin (digital switch input channel two), EB_B0 pin, EB_B1 pin, EB_B2 pin, EB_B3 pin, EB_B4 pin, EB_B5 pin, EB_B6 pin, EB_B7 pin, EB_B8 pin, EB_B9 pin, EB_B10 pin, EB_B11 pin, EB_B12 pin, EB_B13 pin, EB_B14 pin, EB_B15 pin, and EB_B16 pin. The EB_B pin represents a digital switch input pin. The number of digital switch input pins is the same as the number of the third switch unit, and they correspond one-to-one. The digital switch input pins are connected one-to-one with the EN pin of the third switch unit.

[0042] The MCU power supply powers the MCU module. The MCU power supply's voltage input pin (VIN) is connected to the external power supply's BAT+ pin, and its output pin (OUT) is connected to the MCU module's voltage input pin (VIN). Its ground pin (GND) is grounded, i.e., connected to the external power supply's BAT- pin. The MCU module's ground pin (GND) is grounded. The MCU module's SPI1_CLK, SPI1_CSN, SPI1_MISO, and SPI1_MISI pins are connected one-to-one to the SPI1_CLK, SPI1_CSN, SPI1_MISO, and SPI1_MISI pins of the cell voltage data acquisition module. The MCU module's enable pin (DC_EN) is connected to the switching power supply chip's enable pin (EN).

[0043] The cell selection matrix switch module is used to selectively connect different individual cells to the active balancing circuit in a time-division multiplexing manner. The cell selection matrix switch module achieves precise charge transfer between individual cells through "selective connection".

[0044] The cell selection matrix switch module consists of multiple opto-solid-state relays. Opto-isolated solid-state relays are electronic switching devices that achieve electrical isolation between input and output circuits through opto-coupling technology. Multiple opto-solid-state relays form a matrix switch for selecting individual cells, which is controlled by the cell equalization control module.

[0045] The cell selection matrix switch module includes a first switch unit, a second switch unit, and multiple third switch units. The number of third switch units is one more than the number of individual cell units, and they are connected correspondingly to the individual cell units. That is, each switch unit uses an optically isolated solid-state relay.

[0046] The first switching unit is used to connect the charging management chip of the active balancing constant current and constant voltage power supply module, the third switching unit, and the cell balancing control module. The second switching unit is used to connect the cell balancing control module and the third switching unit.

[0047] See Figure 5 This diagram illustrates the cell selection matrix switch module and its connection to the cells (BT1~BT16). The first, second, and third switch units each include a voltage input pin (VIN), an output pin (OUT), and an enable pin (EN). The voltage input pin (VIN) of the first switch unit connects to the voltage output pin (VOUT) of the charging management chip, and the output pin (OUT) connects to the voltage input pin (VIN) of the third switch unit. The enable pin (EN) connects to the digital switch input channel of the cell balancing control module, specifically to pin SW_1 or pin SW_2. The voltage input pin (VIN) of the second switch unit connects to ISO_BAT-, the output pin (OUT) connects to the voltage input pin (VIN) of the third switch unit, and the enable pin (EN) connects to the digital switch input channel of the cell balancing control module, specifically to pin SW_1 or pin SW_2. The output pin (OUT) of the third switching unit is connected to the individual cell, and the enable pin (EN) is connected to the digital switch input pin (one of EB_B0~EB_B16) of the cell equalization control module. The enable pins (EN) of the following 17 third switching units are connected to the 17 digital switch input pins one by one.

[0048] Specifically, there are two first switching units (switching units 18 and 19) and two second switching units (switching units 20 and 21), and 17 third switching units (switching units 1 to 17). Switching unit 1 is connected to the positive terminal of cell 16 and the BAT16 pin of the cell voltage acquisition module. Switching unit 2 is connected to the positive terminal of cell 15, the negative terminal of cell 16, and the BAT15 pin of the cell voltage acquisition module. Switching unit 3 is connected to the positive terminal of cell 14, the negative terminal of cell 15, and the BAT14 pin of the cell voltage acquisition module. And so on, switching units 4 to 16. Switching unit 16 is connected to the positive terminal of cell 1, the negative terminal of cell 2, and the BAT1 pin of the cell voltage acquisition module. Switching unit 17 is connected to the negative terminal of cell 1 and the BAT0 pin of the cell voltage acquisition module.

[0049] One of the first switch units (switch unit 18) and one of the second switch units (switch unit 20) are connected to a portion of the third switch units, specifically switch units 1, 3, 5, 7, 9, 11, 13, 15, and 17. Another first switch unit (switch unit 18) and another second switch unit (switch unit 21) are connected to another portion of the third switch units, specifically switch units 2, 4, 6, 8, 10, 12, 14, and 16.

[0050] The active balancing method of the lithium battery constant current constant voltage active balancing device includes the following steps: Based on the assessment, it can be determined whether any individual battery cells require balancing; If there are individual cells that need to be balanced, the cell balancing control module turns on the active balancing constant current and constant voltage power supply module through the DC_EN signal. The active balancing constant current and constant voltage power supply module outputs power, and the first switch unit and the second switch unit corresponding to the individual cell that needs to be balanced are both turned on. The digital switch input pin corresponding to the individual cell that needs to be balanced is turned on, and the cell selection matrix switch module selects the individual cell that needs to be balanced for balancing.

[0051] In this embodiment, the logic of the equalization algorithm is exemplified as follows: Example 1: In the battery pack, cell 1 (BT1) needs to be balanced. The cell balancing control module turns on the active balancing constant current and constant voltage power supply module through the DC_EN signal. The active balancing constant current and constant voltage power supply module outputs a constant current and constant voltage of 3.65V / 1A. SW_2 is turned on, and EB_B0 and EB_B1 are turned on. The cell selection matrix switch module selects BT1 for balancing.

[0052] Example 2: In the battery pack, cell 2 (BT2) needs to be balanced. The cell balancing control module turns on the active balancing constant current and constant voltage power supply module through the DC_EN signal. The active balancing constant current and constant voltage power supply module outputs a constant current and constant voltage of 3.65V / 1A. SW_1 is turned on, and EB_B1 and EB_B2 are turned on. The cell selection matrix switch module selects BT2 for balancing.

[0053] Example 3: In the battery pack, cell 15 (BT15) needs to be balanced. The cell balancing control module turns on the active balancing constant current and constant voltage power supply module through the DC_EN signal. The active balancing constant current and constant voltage power supply module outputs a constant current and constant voltage of 3.65V / 1A. SW_2 is turned on, and EB_B0 and EB_B1 are turned on. The cell selection matrix switch module selects BT15 for balancing.

[0054] Example 4: In the battery pack, cell 16 (BT16) needs to be balanced. The cell balancing control module turns on the active balancing constant current and constant voltage power supply module through the DC_EN signal. The active balancing constant current and constant voltage power supply module outputs a constant current and constant voltage of 3.65V / 1A. SW_1 is turned on, and EB_B1 and EB_B2 are turned on. The cell selection matrix switch module selects BT16 for balancing.

[0055] Other cell balancing algorithms are similar to the examples above.

[0056] The advantages of the lithium battery constant current and constant voltage active balancing device and method of the present invention are as follows: By using an active balancing constant current and constant voltage power supply module, a cell voltage data acquisition module, a cell selection matrix switch module, and a cell balancing control module, the device achieves the following: when the voltage of a single cell is lower than the constant voltage of the active balancing constant current and constant voltage power supply module, the single cell is charged with a constant current; when the voltage of a single cell reaches the constant voltage of the active balancing constant current and constant voltage power supply module, the single cell is charged with the constant voltage. This solves the problem of the BMS front-end AFE chip data acquisition being affected when the cell voltage difference is large and active balancing of the battery pack is performed.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A constant current and constant voltage active balancing device for lithium batteries, characterized in that, include: An active balancing constant current and constant voltage power supply module is used to charge a single battery cell with a constant current when the voltage of the single battery cell is lower than the constant voltage of the active balancing constant current and constant voltage power supply module; and to charge the single battery cell with the constant voltage when the voltage of the single battery cell reaches the constant voltage of the active balancing constant current and constant voltage power supply module. The cell voltage data acquisition module is used to collect the voltage data of individual cells in the cell group; The cell selection matrix switch module includes several optically isolated solid-state relays; The cell balancing control module is used to read the voltage data from the cell voltage data acquisition module, and based on this, controls the cell selection matrix switch module and the active balancing constant current and constant voltage power supply module to enable the active balancing constant current and constant voltage power supply module to achieve charging balancing of individual cells in the cell group.

2. The lithium battery constant current and constant voltage active balancing device as described in claim 1, characterized in that, The active balancing constant current and constant voltage power supply module, the cell voltage data acquisition module, and the cell selection matrix switch module are all connected to individual cells in the cell group. The cell balancing control module is connected to the cell voltage data acquisition module, the cell selection matrix switch module, and the active balancing constant current and constant voltage power supply module.

3. The lithium battery constant current and constant voltage active balancing device as described in claim 2, characterized in that, The cell balancing control module includes an MCU power supply and an MCU module. The MCU power supply is used to power the MCU module, and the MCU module is used to read the voltage data from the cell voltage data acquisition module, and based on this, control the cell selection matrix switch module so that the active balancing constant current and constant voltage power supply module can achieve charging balancing of individual cells in the cell group.

4. The lithium battery constant current and constant voltage active balancing device as described in claim 3, characterized in that, The MCU module includes a voltage input pin, a ground pin, an enable pin, a clock signal pin, a chip select enable pin, a master input / slave output pin, a master output / slave input pin, several digital switch input channels, and multiple digital switch input pins. The input pins of the MCU module are connected to the MCU power supply. The clock signal pin, chip select enable pin, master input / slave output pin, and master output / slave input pin of the MCU module are all connected to the cell voltage data acquisition module. The enable pin of the MCU module is connected to the active equalization constant current / constant voltage power supply module.

5. The lithium battery constant current and constant voltage active balancing device as described in claim 4, characterized in that, The cell selection matrix switch module includes a first switch unit, a second switch unit, and multiple third switch units; the first switch unit, the second switch unit, and the third switch units are all optically isolated solid-state relays; the first switch unit is connected to the active balancing constant current and constant voltage power supply module, the third switch unit, and the cell balancing control module, and the second switch unit is connected to the cell balancing control module and the third switch unit; the number of digital switch input pins is the same as that of the third switch units, and the digital switch input pins are connected one-to-one with the third switch units; the third switch unit is connected to a single cell.

6. The lithium battery constant current and constant voltage active balancing device as described in claim 5, characterized in that, The first switch unit, the second switch unit, and the third switch unit each include a voltage input pin, an output pin, and an enable pin. The first switch unit and the second switch unit are connected to the digital switch input channel through their own enable pins, and the enable pin of the third switch unit is connected to the digital switch input pin.

7. The lithium battery constant current and constant voltage active balancing device as described in claim 6, characterized in that, The active equalization constant current and constant voltage power supply module includes a switching power supply chip, a DC / DC isolated power supply module, and a charging management chip connected in sequence. The charging management chip is connected to the voltage input pin of the first switching unit.

8. A lithium battery constant current and constant voltage active balancing device as described in claim 6, characterized in that, The cell voltage data acquisition module includes a clock signal pin, a chip select enable pin, a master input / slave output pin, a master output / slave input pin, and multiple pins for acquiring individual cell voltages.

9. A lithium battery constant current and constant voltage active balancing device as described in claim 6, characterized in that, The cell balancing control module is used to control the switching of the active balancing constant current and constant voltage power supply module according to the voltage data.

10. The active balancing method of a lithium battery constant current constant voltage active balancing device as described in any one of claims 5-9, characterized in that, include: Based on the assessment, it can be determined whether any individual battery cells require balancing; If equalization is required, the cell equalization control module turns on the active equalization constant current and constant voltage power supply module through the DC_EN signal. The active equalization constant current and constant voltage power supply module outputs power. The first switch unit and the second switch unit corresponding to the cell that needs to be equalized are both turned on. The digital switch input pin corresponding to the cell that needs to be equalized is turned on. The cell selection matrix switch module selects the cell that needs to be equalized for equalization.

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