Battery series voltage equalization circuit and electronic device

Abstract

The application discloses a battery series voltage equalization circuit and electronic equipment, and relates to the technical field of power management, which comprises a battery pack, a voltage conversion unit, a on-off control unit and a voltage equalization control unit. The voltage conversion unit is used for outputting two charging voltages suitable for overall battery pack charging and single battery charging; the on-off control unit is used for establishing an electrical connection path between the voltage conversion unit and the overall battery pack or any single battery; and the voltage equalization control unit is used for detecting the total voltage of the battery pack and the voltage of each single battery, controlling the voltage conversion unit to switch the charging voltage type according to the detection result, and controlling the on-off state of the on-off control unit, so as to selectively execute overall charging of the battery pack or separate charging of the single battery whose voltage does not reach a preset value. The application realizes the charging mode of overall charging + separate supplement of the overall battery pack, guarantees the charging efficiency, and effectively solves the problem of charging imbalance of each single battery in the battery pack caused by individual differences.

Description

Technical Field

[0001] This application relates to the field of power management technology, and in particular to a battery series voltage equalization circuit and electronic device. Background Technology

[0002] With the widespread use of portable electronic devices and power tools, multi-cell battery series connection has become a common power supply method. To meet the higher operating voltage requirements of these devices, multiple individual cells are typically connected in series to form a battery pack to increase the output voltage. For example, in many applications, four lithium batteries need to be used in series to achieve an operating voltage range of 14.8V to 16.8V.

[0003] However, in actual use, series-connected battery packs commonly suffer from voltage imbalance during charging. Due to differences in production batches, usage time, internal resistance, and actual capacity among individual cells within the pack, the charging speed and state of charge of each cell are inconsistent. When using a constant current / constant voltage method to charge the entire battery pack, some cells may be fully charged while others are not. Continuing to charge could lead to overcharging of the fully charged cells, posing a safety hazard; stopping charging would prevent the partially charged cells from reaching their rated capacity, resulting in a decrease in the overall effective capacity of the battery pack and impacting the device's runtime and performance. Utility Model Content

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a battery series voltage equalization circuit and electronic device, which can avoid the problem of uneven charging caused by individual differences among individual cells in a battery pack.

[0005] In a first aspect, embodiments of this application provide a battery series voltage equalization circuit.

[0006] The battery series voltage equalization circuit according to an embodiment of this application includes: The battery series voltage equalization circuit according to the embodiments of this application has at least the following beneficial effects: by setting a voltage conversion unit capable of outputting two different charging voltages, and cooperating with the on / off control unit and the voltage equalization control unit, intelligent voltage equalization charging of the series battery pack is realized. The battery series voltage equalization circuit in the embodiment uses a first charging voltage to charge the entire battery pack. After the overall charging is completed, the voltage equalization control unit detects the voltage state of each individual battery, identifies the individual battery whose voltage has not reached a preset value, then switches the voltage conversion unit to output a second charging voltage, and establishes an electrical connection path with the individual battery through the on / off control unit for targeted individual charging compensation. This "overall charging + individual supplementation" method not only ensures charging efficiency but also effectively solves the problem of uneven charging caused by individual differences among the individual batteries in the battery pack, avoiding overcharging or undercharging of some batteries, thereby improving the overall capacity utilization of the battery pack, extending battery life, and enhancing the safety of the charging process. Compared with existing technologies, the battery series voltage equalization circuit of this embodiment realizes the charging control of the entire battery pack and each individual battery, without the need to configure an independent charging circuit for each battery, which significantly simplifies the circuit structure, reduces system cost and size, and improves voltage equalization efficiency and reliability, and has good practical value and promotion prospects.

[0007] According to some embodiments of this application, the voltage conversion unit is provided with a voltage control input terminal, a positive output terminal and a negative output terminal, and the voltage conversion unit is used to selectively output the first charging voltage or the second charging voltage between the positive output terminal and the negative output terminal according to the mode selection signal received by the voltage control input terminal.

[0008] According to some embodiments of this application, the on / off control unit includes a plurality of positive switching devices and a plurality of negative switching devices, each corresponding to a single battery; the input terminal of the positive switching device is connected to the positive output terminal of the voltage conversion unit, and the output terminal of the positive switching device is connected to the positive terminal of the corresponding single battery; the input terminal of the negative switching device is connected to the negative terminal of the corresponding single battery, and the output terminal of the negative switching device is connected to the negative output terminal of the voltage conversion unit.

[0009] According to some embodiments of this application, the voltage equalization control unit is provided with a plurality of voltage detection input terminals, a plurality of switch control output terminals and at least one voltage mode output terminal; the voltage detection input terminals are connected one-to-one with each terminal of a single cell in the battery pack, the switch control output terminals are connected to the control terminal of the positive electrode switching device or the control terminal of the negative electrode switching device, and the voltage mode output terminal is connected to the voltage control input terminal of the voltage conversion unit. The voltage equalization control unit is used to detect the total voltage of the battery pack and the voltage of each individual cell through the voltage detection input terminal, and control the voltage conversion unit to selectively output the first charging voltage or the second charging voltage according to the detection result; the voltage equalization control unit is also used to control the on / off state of the positive and negative switching devices through the switch control output terminal, so as to apply the first charging voltage to the two ends of the battery pack, or apply the second charging voltage to the two ends of the individual cell whose voltage has not reached the preset value.

[0010] According to some embodiments of this application, the voltage conversion unit includes: A voltage conversion module, wherein the output terminal of the voltage conversion module is connected to the positive output terminal; A voltage regulation circuit is connected to the voltage feedback terminal of the voltage conversion module and to the voltage mode output terminal of the voltage equalization control unit. The voltage regulation circuit is used to adjust the output voltage of the voltage conversion module under the control of the mode selection signal.

[0011] According to some embodiments of this application, the voltage conversion module is a DC-DC conversion chip; the voltage regulation circuit includes a first resistor, a second resistor, a third resistor, and a voltage divider switch device. One end of the first resistor is connected to the output terminal of the DC-DC conversion chip, and the other end is connected to the second resistor. The other end of the second resistor is grounded. The third resistor is connected in series with the voltage divider switch device and then in parallel across the two ends of the second resistor. The control terminal of the voltage divider switch device is connected to the voltage mode output terminal of the voltage equalization control unit.

[0012] According to some embodiments of this application, a current detection unit is further included, which is connected in series with one of the positive output terminal and the negative output terminal; the voltage equalization control unit further includes at least one current detection input terminal, which is connected to the current signal output terminal of the current detection unit to receive a charging current signal; the voltage equalization control unit is also used to collect the total voltage of the battery pack in response to the charging current signal being lower than a preset current threshold.

[0013] According to some embodiments of this application, the current detection unit includes a sampling resistor connected in series with the negative output terminal, and one end of the sampling resistor is connected to the current detection input terminal of the voltage equalization control unit.

[0014] According to some embodiments of this application, an alarm indication circuit is also included, connected to the equalization control unit, for issuing an alarm signal when the equalization is abnormal.

[0015] Secondly, embodiments of this application provide an electronic device. The electronic device includes the battery series voltage equalization circuit described in any embodiment of the first aspect. Attached Figure Description

[0016] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the module structure of the battery series voltage equalization circuit in an embodiment. Figure 2 This is a schematic diagram of the circuit structure of a battery series voltage equalization circuit as an example. Detailed Implementation

[0017] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0018] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0021] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] In a first aspect, embodiments of this application provide a battery series voltage equalization circuit.

[0023] like Figure 1 As shown, the battery series voltage equalization circuit in the embodiment includes a battery pack, a voltage conversion unit, an on / off control unit, and a voltage equalization control unit.

[0024] A battery pack consists of several individual cells connected in series. For example, Figure 2 As shown, the battery pack includes four individual cells, namely, the first individual cell 1#, the second individual cell 2#, the third individual cell 3#, and the fourth individual cell 4#, which are connected in series.

[0025] The following example illustrates the battery series voltage equalization circuit using four individual batteries connected in series as an example. The nominal voltage of a single battery in the example is 4.2V, therefore the total voltage of the battery pack after four batteries are connected in series is 16.8V. It should be noted that the number of individual batteries in the battery pack can be adjusted according to actual needs; for example, it can be two, three, five, or more individual batteries connected in series. The nominal voltage of each individual battery can also be selected according to the actual usage scenario.

[0026] The voltage conversion unit outputs a first charging voltage and a second charging voltage. The first charging voltage is adapted to the overall battery pack, and the second charging voltage is adapted to a single battery cell. For example, the first charging voltage is 16.8V for charging a four-cell battery pack connected in series; the second charging voltage is 4.2V for charging a single battery cell individually. The voltage conversion unit can switch between the two charging voltages according to a control signal to adapt to different charging mode requirements.

[0027] The on / off control unit is used to establish an electrical connection between the voltage conversion unit and the battery pack as a whole, or with any individual cell within the battery pack. The on / off control unit selects the charging current path by controlling the on / off states of different switching devices. When the entire battery pack needs to be charged, the on / off control unit establishes a connection between the voltage conversion unit and the positive and negative terminals of the battery pack; when a single cell needs to be charged individually, the on / off control unit establishes a connection between the voltage conversion unit and the positive and negative terminals of that single cell.

[0028] The voltage equalization control unit is used to detect the total voltage of the battery pack and the voltage of each individual cell. Based on the detection results, it controls the voltage conversion unit to switch the output charging voltage type and controls the on / off state of the on / off control unit to selectively perform overall charging of the battery pack or individual charging of individual cells whose voltage has not reached the preset value.

[0029] The voltage equalization control unit monitors the total voltage of the battery pack and the voltage of each individual cell in real time, comparing the detected values ​​with preset target voltage values. When the total battery pack voltage does not reach the target value, the voltage equalization control unit controls the voltage conversion unit to output a first charging voltage, and simultaneously controls the on / off control unit to establish a connection path between the voltage conversion unit and the entire battery pack, charging the entire battery pack. After the entire battery pack is fully charged, the voltage equalization control unit further monitors the voltage of each individual cell. If any individual cell is found to have a voltage below the preset value, it indicates a voltage imbalance in the battery pack, requiring voltage equalization. At this time, the voltage equalization control unit controls the voltage conversion unit to output a second charging voltage, and controls the on / off control unit to sequentially establish a connection path between the voltage conversion unit and the individual cell with insufficient voltage, providing individual supplementary charging to the individual cell with insufficient voltage, thereby achieving voltage equalization of the battery pack.

[0030] The series battery equalization circuit in this embodiment can automatically detect the voltage state of the battery pack and intelligently switch the charging mode. It can charge the entire battery pack as a whole, or perform targeted equalization charging for individual batteries with insufficient voltage. This effectively solves the problem of voltage imbalance in series battery packs, improves the charging and discharging performance and lifespan of the battery pack, and ensures the safety of battery use.

[0031] The following example uses four individual batteries connected in series to form a battery pack to illustrate the battery series voltage equalization circuit in more detail. In this example, the nominal voltage of a single battery is 4.2V, therefore the total voltage of the battery pack after four batteries are connected in series is 16.8V. It should be noted that the number of individual batteries in the battery pack can be adjusted according to actual needs; for example, it can be two, three, five, or more individual batteries connected in series. The nominal voltage of each individual battery can also be selected according to the actual usage scenario.

[0032] like Figure 1As shown in the figure, the voltage conversion unit has a voltage control input terminal, a positive output terminal, and a negative output terminal. The voltage conversion unit selectively outputs a first charging voltage or a second charging voltage between the positive and negative output terminals based on the mode selection signal received from the voltage control input terminal. Specifically, the voltage control input terminal is connected to the voltage equalization control unit and receives the mode selection signal sent by the voltage equalization control unit. This mode selection signal indicates which charging voltage the voltage conversion unit should output. The positive output terminal serves as the positive output port of the voltage conversion unit, and the negative output terminal serves as the negative output port; the charging voltage is output between these two ports. When the voltage control input terminal receives the first mode selection signal, the voltage conversion unit outputs the first charging voltage (e.g., 16.8V) between the positive and negative output terminals; when the voltage control input terminal receives the second mode selection signal, the voltage conversion unit outputs the second charging voltage (e.g., 4.2V) between the positive and negative output terminals. In this way, the voltage conversion unit can flexibly switch the output voltage according to actual charging needs, meeting different requirements for overall charging and individual voltage equalization charging.

[0033] The on / off control unit includes several positive switching devices and several negative switching devices, with each positive and negative switching device corresponding to a single battery cell. Figure 2 In the illustrated embodiment, since the battery pack comprises four individual cells, the on / off control unit includes four positive switching devices K1, K2, K3, and K4 and four negative switching devices K5, K6, K7, and K8. Specifically, positive switching device K1 corresponds to the fourth individual cell (4#), positive switching device K2 corresponds to the third individual cell (3#), positive switching device K3 corresponds to the second individual cell (2#), and positive switching device K4 corresponds to the first individual cell (1#). Similarly, negative switching device K5 corresponds to the fourth individual cell (4#), negative switching device K6 corresponds to the third individual cell (3#), negative switching device K7 corresponds to the second individual cell (2#), and negative switching device K8 corresponds to the first individual cell (1#).

[0034] The input terminal of each positive switching device is connected to the positive output terminal of the voltage conversion unit, and the output terminal of each positive switching device is connected to the positive terminal of the corresponding single battery. Specifically, the input terminal of positive switching device K1 is connected to the positive output terminal, and its output terminal is connected to the positive terminal of the fourth single battery #4; the input terminal of positive switching device K2 is connected to the positive output terminal, and its output terminal is connected to the positive terminal of the third single battery #3; the input terminal of positive switching device K3 is connected to the positive output terminal, and its output terminal is connected to the positive terminal of the second single battery #2; the input terminal of positive switching device K4 is connected to the positive output terminal, and its output terminal is connected to the positive terminal of the first single battery #1. The input terminal of each negative switching device is connected to the negative terminal of the corresponding single battery, and the output terminal of each negative switching device is connected to the negative output terminal of the voltage conversion unit. Specifically, the input terminal of negative switch K5 is connected to the negative terminal of the fourth single battery 4#, and its output terminal is connected to the negative output terminal; the input terminal of negative switch K6 is connected to the negative terminal of the third single battery 3#, and its output terminal is connected to the negative output terminal; the input terminal of negative switch K7 is connected to the negative terminal of the second single battery 2#, and its output terminal is connected to the negative output terminal; the input terminal of negative switch K8 is connected to the negative terminal of the first single battery 1#, and its output terminal is connected to the negative output terminal.

[0035] Through the above connection method, the on / off control unit can flexibly establish a charging path between the voltage conversion unit and the entire battery pack or any single cell by controlling the on / off states of different positive and negative switching devices. For example, when the entire battery pack needs to be charged, the positive switching device K1 and the negative switching device K8 are simultaneously turned on, while the other switching devices are turned off. At this time, the charging current flows from the positive output terminal through K1 into the positive terminal of the fourth single cell 4#, flows through the four series-connected single cells in sequence, and finally flows from the negative terminal of the first single cell 1# through K8 to the negative output terminal, thus charging the entire battery pack. When a single cell (e.g., the third single cell 3#) needs to be charged individually, the positive switching device K2 and the negative switching device K6 are simultaneously turned on, while the other switching devices are turned off. At this time, the charging current flows from the positive output terminal through K2 into the positive terminal of the third single cell 3#, and from the negative terminal of the third single cell 3# through K6 to the negative output terminal, thus charging the third single cell 3# individually.

[0036] The voltage equalization control unit has several voltage detection input terminals, several switch control output terminals, and at least one voltage mode output terminal. Figure 2In the illustrated embodiment, the voltage equalization control unit is implemented using a voltage equalization control chip U1. The voltage detection input terminals are connected one-to-one with each terminal of a single cell in the battery pack. In this embodiment, since there are four single cells connected in series, there are a total of five voltage detection points (including the highest and lowest potential terminals of the battery pack and the connection points between the individual cells). Therefore, the voltage equalization control unit U1 has five voltage detection input terminals. Specifically, the first voltage detection input terminal (e.g., pin V1) of the voltage equalization control unit U1 is connected to the negative terminal of the first single cell 1# (i.e., the negative terminal of the battery pack); the second voltage detection input terminal (e.g., pin V2) is connected to the positive terminal of the first single cell 1# and the negative terminal of the second single cell 2#; the third voltage detection input terminal (e.g., pin V3) is connected to the positive terminal of the second single cell 2# and the negative terminal of the third single cell 3#; the fourth voltage detection input terminal (e.g., pin V4) is connected to the positive terminal of the third single cell 3# and the negative terminal of the fourth single cell 4#; and the fifth voltage detection input terminal (e.g., pin VCC) is connected to the positive terminal of the fourth single cell 4# (i.e., the positive terminal of the battery pack). Through these five voltage detection input terminals, the voltage equalization control unit can detect the total voltage of the battery pack and the voltage of each individual cell.

[0037] The switch control output terminal is connected to the corresponding control terminal of the positive or negative switching device. Figure 2 In the illustrated embodiment, the voltage equalization control unit U1 has eight switch control output terminals (e.g., pins K1 to K8), which are respectively connected to the control terminals of eight switching devices K1 to K8. Through these switch control output terminals, the voltage equalization control unit can independently control the on / off state of each switching device.

[0038] The voltage-mode output is connected to the voltage control input of the voltage conversion unit. For example... Figure 2 As shown, the voltage mode output terminal of the voltage equalization control unit U1 (e.g., the GATE pin, corresponding to...) Figure 2 Pin 17 (marked as U1) is connected to the voltage control input of the voltage conversion unit. The voltage equalization control unit outputs a mode selection signal through this pin to control the voltage conversion unit to switch between different charging voltages.

[0039] The voltage equalization control unit detects the total voltage of the battery pack and the voltage of each individual cell through its voltage detection input. Based on the detection results, it controls the voltage conversion unit to selectively output a first charging voltage or a second charging voltage. Specifically, the voltage equalization control unit obtains the total voltage of the battery pack by comparing the voltage difference between the highest and lowest potential terminals; and obtains the voltage of the corresponding individual cell by comparing the voltage difference between two adjacent voltage detection input terminals. For example, at the initial stage of charging, when the battery pack is being charged as a whole, the voltage equalization control unit outputs a first mode selection signal through its voltage mode output terminal to control the voltage conversion unit to output the first charging voltage. When charging reaches a preset time threshold, or the overall charging current drops to a preset current threshold, if the total voltage of the battery pack is detected to be below the target value (total voltage value of the battery pack, such as 16.8V), the voltage equalization control unit outputs a second mode selection signal through its voltage mode output terminal to control the voltage conversion unit to output the second charging voltage.

[0040] like Figure 2 As shown, the voltage equalization control unit is also used to control the on / off state of the positive and negative switching devices via the switch control output terminal, so as to apply a first charging voltage to both ends of the battery pack, or apply a second charging voltage to both ends of a single cell whose voltage has not reached a preset value. In the overall charging mode, the voltage equalization control unit controls the positive switching device K1 and the negative switching device K8 to be turned on, while the other switching devices are turned off, so that the first charging voltage is applied to both ends of the battery pack. In the single-cell voltage equalization charging mode, the voltage equalization control unit controls the corresponding pair of positive and negative switching devices to be turned on, while the other switching devices are turned off, based on the detected single cell with insufficient voltage, so that the second charging voltage is applied to both ends of the single cell with insufficient voltage. For example, if the voltage of the third single cell 3# is detected to be insufficient, the positive switching device K2 and the negative switching device K6 are controlled to be turned on, while the other switching devices are turned off, so that the third single cell 3# is charged separately.

[0041] Understandably, the battery series voltage equalization circuit in the embodiment also includes a current detection unit. For example... Figure 1 and Figure 2 As shown, the current detection unit is connected in series with one of the positive and negative output terminals to detect the charging current flowing through the voltage conversion unit. In this embodiment, the current detection unit is connected in series in the circuit of the negative output terminal, meaning that the charging current flows through the current detection unit and then to the negative output terminal of the voltage conversion unit. In other embodiments, the current detection unit can also be connected in series in the circuit of the positive output terminal.

[0042] Accordingly, the voltage equalization control unit also includes at least one current detection input terminal, which is connected to the current signal output terminal of the current detection unit to receive the charging current signal. For example... Figure 2In the illustrated embodiment, the current detection input of the voltage equalization control unit U1 is pin 18 of U1. This pin is connected to the current detection unit and receives the charging current signal in real time. Through this current detection input, the voltage equalization control unit can determine the current charging current magnitude. The voltage equalization control unit is also used to collect the total voltage of the battery pack in response to the charging current signal falling below a preset current threshold. Specifically, in the initial stage of the charging process, the voltage of the battery pack or individual cells is low, and the charging current is high. As the charging process progresses, the battery voltage gradually increases, and the charging current gradually decreases. When the charging current drops below the preset current threshold, it indicates that the current object being charged (battery pack or individual cell) is close to being fully charged.

[0043] For example, the preset current threshold is 0.15A. When the voltage equalization control unit detects that the charging current is below 0.15A, it determines that the current charging stage is nearing completion. At this time, the voltage equalization control unit collects the total voltage of the battery pack and compares the collected total voltage value with the preset target voltage value (e.g., 16.8V). If the total voltage of the battery pack reaches or is close to the target voltage value, it indicates that the overall charging is complete; if the total voltage of the battery pack is significantly lower than the target voltage value, it indicates that there is a voltage imbalance within the battery pack. Subsequently, the voltage of each individual cell is detected sequentially. If it is found that the voltage of an individual cell has not reached the preset value (e.g., 4.2V), the individual cell with insufficient voltage is charged separately.

[0044] By setting up the current detection unit, the voltage equalization control unit can monitor the changes in charging current in real time, accurately judge the progress of the charging stage, and thus switch the charging mode and detect the voltage status at the appropriate time (from the overall charging mode of the battery pack to the voltage equalization charging mode of the individual cells), thereby improving the accuracy and intelligence of charging control.

[0045] Optional, such as Figure 2 As shown, the current detection unit includes a sampling resistor RCS. The sampling resistor RCS is connected in series with the negative output terminal. For example, one end of the sampling resistor RCS is connected to the output terminal of the negative switching device, and the other end is grounded (SGND) through a voltage conversion unit. When the charging current flows through the sampling resistor RCS, a voltage drop is generated across the sampling resistor RCS, which is proportional to the current flowing through it. One end of the sampling resistor RCS is connected to the current detection input terminal of the voltage equalization control unit. Specifically, the end of the sampling resistor RCS furthest from the negative switching device is connected to the voltage equalization control unit (such as pin 18 of U1) via a connecting wire. The voltage equalization control unit calculates the current charging current value by detecting the voltage difference across the sampling resistor RCS.

[0046] In some embodiments, the voltage conversion unit includes a voltage conversion module and a voltage regulation circuit. The voltage conversion module converts the input voltage into an adjustable output voltage to charge the battery pack or individual battery. The output terminal of the voltage conversion module is connected to the positive output terminal to provide charging current to the battery pack or individual battery. Figure 2 In the illustrated embodiment, the voltage conversion module is a DC-DC converter chip U2, which converts the input DC voltage into the required charging voltage. The DC-DC converter chip U2 has an output terminal Vo, a feedback terminal FB, and other necessary pins (such as a power input terminal Vin, a ground terminal GND, and an enable terminal). The output terminal Vo serves as the positive output terminal of the voltage conversion unit, outputting the charging voltage. The voltage regulation circuit is connected to the voltage feedback terminal of the voltage conversion module and also to the voltage mode output terminal of the voltage equalization control unit. The voltage regulation circuit is used to adjust the output voltage of the voltage conversion module under the control of the mode selection signal. Specifically, the voltage regulation circuit controls the DC-DC converter chip U2 to adjust its output voltage by changing the feedback voltage value at the voltage feedback terminal, thereby achieving the switching between the first charging voltage and the second charging voltage.

[0047] The working principle of a DC-DC converter chip is based on feedback control: the chip internally compares the voltage at the feedback terminal FB with an internal reference voltage, and adjusts the voltage at the output terminal Vo to stabilize the voltage at the feedback terminal FB at the reference voltage value. Therefore, by changing the voltage division ratio at the feedback terminal FB, the output voltage at the output terminal Vo can be changed. The voltage regulation circuit achieves output voltage switching by changing the voltage division ratio at the feedback terminal.

[0048] Furthermore, such as Figure 2As shown, the voltage regulation circuit includes a first resistor R6, a second resistor R7, a third resistor R8, and a voltage divider switch Q1. One end of the first resistor R6 is connected to the output pin Vo of the DC-DC converter chip U2, and the other end is connected to the feedback pin FB of the DC-DC converter chip U2. The first resistor R6 serves as the upper voltage divider resistor in the voltage divider circuit, used for voltage division sampling of the output voltage. One end of the second resistor R7 is connected to the feedback pin FB of the DC-DC converter chip U2, and the other end is grounded (SGND). The second resistor R7 serves as the lower voltage divider resistor in the voltage divider circuit, forming a basic voltage divider network together with the first resistor R6. The third resistor R8 is connected in series with the voltage divider switch Q1 and then in parallel across the two ends of the second resistor R7. Specifically, one end of the third resistor R8 is connected to the feedback pin FB, and the other end is connected to one current terminal (e.g., drain or collector) of the voltage divider switch Q1; the other current terminal (e.g., source or emitter) of the voltage divider switch Q1 is grounded (SGND). Thus, the series branch of the third resistor R8 and the voltage divider switch Q1 is connected in parallel with the second resistor R7. The control terminal (e.g., gate or base) of the voltage divider switch Q1 is connected to the voltage-mode output terminal of the voltage equalization control unit U1. In this embodiment, the voltage divider switch Q1 is a transistor, and its base is connected to the GATE pin (pin 17) of the voltage equalization control unit U1, with base current limited by the connecting resistor R9. The emitter of the voltage divider switch Q1 is grounded, and the collector is connected to the third resistor R8. In other embodiments, the voltage divider switch Q1 can also be other types of switching devices such as a MOSFET.

[0049] When the voltage equalization control unit outputs a high-level signal through its voltage-mode output terminal, the voltage divider switch Q1 is turned on. The third resistor R8 is connected to ground through the turned-on voltage divider switch Q1. At this time, the third resistor R8 and the second resistor R7 are connected in parallel, forming a smaller equivalent lower voltage divider resistance. According to the voltage divider principle, the voltage division value at the feedback terminal FB decreases. To raise the voltage at the feedback terminal FB back to the reference voltage value, the DC-DC converter chip U2 increases the voltage at the output terminal Vo, thereby outputting a higher first charging voltage (e.g., 16.8V). At this time, the voltage conversion unit outputs the first charging voltage to charge the battery pack as a whole. When the voltage equalization control unit outputs a low-level signal through its voltage-mode output terminal, the voltage divider switch Q1 is turned off, and the parallel branch of the third resistor R8 and the second resistor R7 is broken. At this time, only the second resistor R7 acts as the lower voltage divider resistance. According to the voltage divider principle, the voltage division value at the feedback terminal FB increases. To bring the voltage at the feedback terminal FB back to the reference voltage, the DC-DC converter chip U2 reduces the voltage at the output terminal Vo, thus outputting a lower second charging voltage (e.g., 4.2V). At this time, the voltage conversion unit outputs the second charging voltage for equalizing the voltage of individual cells. Through the cooperation of the voltage conversion module and the voltage regulation circuit, the voltage conversion unit can flexibly and accurately switch between the two charging voltages according to the control signal from the equalization control unit, meeting the different needs of overall battery pack charging and individual cell equalization charging. In some embodiments, the battery series voltage equalization circuit further includes an alarm indication circuit. The alarm indication circuit is connected to the voltage equalization control unit and is used to issue an alarm signal when voltage equalization is abnormal, to alert the user that the battery pack is in an abnormal state and requires inspection or maintenance. For example, the alarm indication circuit includes an alarm indication device. Figure 2 As shown, taking the red LED1 as the alarm indicator as an example, the alarm output terminal of the voltage equalization control unit U1 can output a control signal to control the on / off state of the alarm indicator LED1. When the voltage equalization control unit detects an abnormal voltage equalization, the alarm output terminal outputs a low-level signal, causing the alarm indicator LED1 to conduct and emit a red light alarm signal; when the battery pack is working normally, the alarm output terminal outputs a high-level signal, and the alarm indicator LED1 does not emit light.

[0050] For example, the determination of voltage equalization anomalies may include, but is not limited to, the following situations: Scenario 1: After the voltage equalization control unit executes multiple voltage equalization processes, the voltage of some individual cells in the battery pack still fails to reach the target value. Specifically, after the voltage equalization control unit completes the overall charging of the battery pack, if it detects that the voltage of one or more individual cells has not reached the preset target value (e.g., 4.2V), it initiates the voltage equalization charging process to charge the individual cells with insufficient voltage separately. If the voltage of a single cell still fails to reach the target value after being charged separately for a preset time threshold (e.g., 30 minutes, 1 hour, or 2 hours), then the single cell is determined to be abnormal. Scenario 2: During the voltage equalization charging process, an abnormal charging current of a single cell is detected. Under normal circumstances, when charging a single cell, the charging current should gradually decrease as the battery voltage increases. If the charging current is detected to remain at a high level without decreasing, or if the charging current suddenly increases abnormally, it may indicate that the single cell has an internal short circuit or other fault. Scenario 3: During the voltage equalization charging process, an abnormal voltage of a single cell is detected. For example, if, during the charging of a single battery, the voltage of that single battery drops instead of increasing, or the voltage value exceeds the normal range (e.g., exceeding the single battery's maximum safe voltage of 4.3V), then that single battery is determined to be abnormal. Scenario four: Excessive voltage differences are detected between the individual batteries within the battery pack. For example, after completing overall charging or equalization charging, if the voltage difference between the highest-voltage and lowest-voltage single battery in the battery pack exceeds a preset difference threshold (e.g., 0.5V or 1V), then the battery pack voltage is determined to be severely unbalanced, the equalization function cannot work effectively, and the alarm indicator circuit is activated to issue an alarm signal. Scenario five: During overall charging, the charging time is detected to be too long and the battery is still not fully charged. For example, if the overall charging of the battery pack exceeds the preset maximum charging time (e.g., 8 hours or 10 hours), and the total voltage of the battery pack still has not reached the target value, or the charging current still has not decreased to the preset current threshold, then the charging is determined to be abnormal, and the alarm indicator circuit is activated to issue an alarm signal.

[0051] Understandably, in some embodiments, the voltage equalization control unit U1 includes a timer and a counter to record charging time and the number of voltage equalization attempts. The voltage equalization control unit also includes anomaly detection logic to determine whether any of the aforementioned voltage equalization anomalies are met based on detected parameters such as voltage, current, and time. Once a voltage equalization anomaly is detected, the voltage equalization control unit immediately controls the alarm indication circuit to issue an alarm signal and may simultaneously stop the charging process to avoid potential safety risks from continued charging of the abnormal battery. In other embodiments, the alarm indication circuit may also include a buzzer, speaker, or other audible alarm device, or send alarm information to the user's mobile phone or other terminal device via a wireless communication module. The alarm indication circuit can also be set with different alarm modes, such as indicating different types of anomalies through different LED flashing frequencies or different buzzer sounds.

[0052] Secondly, embodiments of this application provide an electronic device. The electronic device of this embodiment includes a battery series voltage equalization circuit according to any embodiment of the first aspect. The principle and beneficial effects of the electronic device of this embodiment are derived from the battery series voltage equalization circuit of the first aspect embodiment; therefore, the specific implementation details of the electronic device of this embodiment will not be repeated here.

[0053] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A battery series voltage equalization circuit, characterized in that, include: A battery pack consists of several individual cells connected in series. A voltage conversion unit is used to output a first charging voltage and a second charging voltage, wherein the first charging voltage is a charging voltage adapted to the entire battery pack, and the second charging voltage is a charging voltage adapted to the individual battery. An on / off control unit is used to establish an electrical connection path between the voltage conversion unit and the battery pack as a whole, or with any of the individual cells in the battery pack. The voltage equalization control unit is used to detect the total voltage of the battery pack and the voltage of each individual cell. Based on the detection results, it controls the voltage conversion unit to switch the output charging voltage type and controls the on / off state of the on / off control unit to selectively perform overall charging of the battery pack or individual charging of individual cells whose voltage has not reached the preset value.

2. The battery series voltage equalization circuit according to claim 1, characterized in that, The voltage conversion unit is provided with a voltage control input terminal, a positive output terminal and a negative output terminal. The voltage conversion unit is used to selectively output the first charging voltage or the second charging voltage between the positive output terminal and the negative output terminal according to the mode selection signal received by the voltage control input terminal.

3. The battery series voltage equalization circuit according to claim 2, characterized in that, The on / off control unit includes several positive switching devices and several negative switching devices, each corresponding to a single battery. The input terminal of the positive switching device is connected to the positive output terminal of the voltage conversion unit, and the output terminal of the positive switching device is connected to the positive terminal of the corresponding single battery. The input terminal of the negative switching device is connected to the negative terminal of the corresponding single battery, and the output terminal of the negative switching device is connected to the negative output terminal of the voltage conversion unit.

4. The battery series voltage equalization circuit according to claim 3, characterized in that, The voltage equalization control unit is provided with several voltage detection input terminals, several switch control output terminals, and at least one voltage mode output terminal; the voltage detection input terminals are connected one-to-one with each terminal of the single cell in the battery pack, the switch control output terminals are connected to the control terminal of the positive electrode switching device or the control terminal of the negative electrode switching device, and the voltage mode output terminal is connected to the voltage control input terminal of the voltage conversion unit. The voltage equalization control unit is used to detect the total voltage of the battery pack and the voltage of each individual cell through the voltage detection input terminal, and control the voltage conversion unit to selectively output the first charging voltage or the second charging voltage according to the detection result; the voltage equalization control unit is also used to control the on / off state of the positive and negative switching devices through the switch control output terminal, so as to apply the first charging voltage to the two ends of the battery pack, or apply the second charging voltage to the two ends of the individual cell whose voltage has not reached the preset value.

5. The battery series voltage equalization circuit according to claim 4, characterized in that, The voltage conversion unit includes: A voltage conversion module, wherein the output terminal of the voltage conversion module is connected to the positive output terminal; A voltage regulation circuit is connected to the voltage feedback terminal of the voltage conversion module and to the voltage mode output terminal of the voltage equalization control unit. The voltage regulation circuit is used to adjust the output voltage of the voltage conversion module under the control of the mode selection signal.

6. The battery series voltage equalization circuit according to claim 5, characterized in that, The voltage conversion module is a DC-DC converter chip; the voltage regulation circuit includes a first resistor, a second resistor, a third resistor, and a voltage divider switch. One end of the first resistor is connected to the output terminal of the DC-DC converter chip, and the other end is connected to the second resistor. The other end of the second resistor is grounded. The third resistor is connected in series with the voltage divider switch and then in parallel across the two ends of the second resistor. The control terminal of the voltage divider switch is connected to the voltage mode output terminal of the voltage equalization control unit.

7. The battery series voltage equalization circuit according to claim 6, characterized in that, It also includes a current detection unit, which is connected in series with one of the positive output terminal and the negative output terminal; the voltage equalization control unit further includes at least one current detection input terminal, which is connected to the current signal output terminal of the current detection unit to receive the charging current signal; the voltage equalization control unit is also used to collect the total voltage of the battery pack in response to the charging current signal being lower than a preset current threshold.

8. The battery series voltage equalization circuit according to claim 7, characterized in that, The current detection unit includes a sampling resistor connected in series with the negative output terminal, and one end of the sampling resistor is connected to the current detection input terminal of the voltage equalization control unit.

9. The battery series voltage equalization circuit according to claim 1, characterized in that, It also includes an alarm indication circuit, which is connected to the equalization control unit and is used to issue an alarm signal when the equalization is abnormal.

10. An electronic device, characterized in that, The electronic device is equipped with a battery series voltage equalization circuit as described in any one of claims 1-9.

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