Voltage equalization circuit and electronic equipment

Abstract

The embodiment of the utility model discloses a voltage equalization circuit and electronic equipment, and relates to the field of circuits. An existing passive equalization control circuit is upgraded into an active equalization circuit, a single battery needing to be discharged is directly boosted to the rated voltage value of the battery pack by means of cooperation of the passive equalization sub-circuit and the boost conversion unit, the single battery is loaded to the battery pack for charging, and the dual equalization process of active equalization and passive equalization is achieved. The improvement greatly reduces the calorific value of the system, and improves the stability and safety of the system. Under the action of the boost conversion unit, the electric energy of the battery which needs to be discharged originally is converted into a high-voltage signal, and the high-voltage signal is loaded to the battery pack for charging. In the process, the electric energy which is possibly wasted originally is effectively recycled and reused, and the use efficiency of the electric energy is remarkably improved.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and particularly to a voltage equalization circuit and an electronic device. Background Art

[0002] Battery packs are basically series systems of single cells. The inconsistent performance of single cells and the barrel effect of the battery system will affect the output of the entire battery pack. For the above reasons, it is necessary to intervene in the unevenness of single cells during the charging and discharging processes to maximize the charging and discharging performance of the battery.

[0003] In the prior art, battery packs generally use passive equalization to perform voltage equalization on the battery pack, that is, the battery node with a higher battery voltage is connected to a discharge resistor for discharging to make it reach a safe voltage. Since this circuit consumes energy in the form of a heating resistor, there are problems of large heat generation and energy waste. Summary of the Utility Model

[0004] The embodiments of the present application provide a voltage equalization circuit and an electronic device, which can solve the problems of large heat generation and energy waste caused by using resistor discharge for voltage equalization in the prior art. The technical solutions are as follows:

[0005] In a first aspect, the embodiments of the present application provide a voltage equalization circuit, which triggers the operation of an active equalization unit through the passive equalization switch of a common passive equalization BMS chip, and is applied to a battery pack composed of n series-connected batteries, including: a voltage detection unit and n boost conversion units, where n is an integer greater than 1;

[0006] Wherein, the voltage detection unit is connected to the positive and negative electrodes of each battery, and there is a one-to-one correspondence between the n batteries and the n boost conversion units. The positive input terminal of the boost conversion unit is connected to the positive electrode of the corresponding battery, and the negative input terminal of the boost conversion unit is connected to the negative electrode of the corresponding battery; the positive output terminal of the boost conversion unit is connected to the positive electrode of the battery pack, and the negative terminal of the boost conversion unit is connected; the voltage detection unit is respectively connected to each boost conversion unit;

[0007] The voltage detection unit is configured to indicate the start of operation of the boost conversion circuit corresponding to the battery when it detects that the voltage of a certain battery in the battery pack is unbalanced and needs to be discharged;

[0008] The boost conversion unit is configured to boost the current voltage signal of the battery to obtain a high voltage signal, where the voltage value of the high voltage signal is equal to the rated voltage value of the battery pack, and load the high voltage signal onto the battery pack for charging.

[0009] In a second aspect, the present application provides an electronic device including the voltage equalization circuit of the present application.

[0010] The beneficial effects brought by the technical solutions provided in some embodiments of the present application at least include:

[0011] Through an innovative voltage equalization mechanism, beneficial effects such as resistor-free discharge, electric energy recovery, flexible scalability, and intelligent management are achieved, significantly improving the performance and usage efficiency of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0013] Figure 1 is a circuit structure diagram of the voltage equalization circuit provided by the present application;

[0014] Figure 2 is another circuit structure diagram of the voltage equalization circuit provided by the embodiments of the present application;

[0015] Figure 3 is yet another circuit structure diagram of the voltage equalization circuit provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0017] Please refer to Figure 2 and Figure 3 , a schematic structural diagram of a voltage equalization circuit provided by an embodiment of the present invention. The voltage equalization circuit includes: a voltage detection unit 0, a boost conversion unit B1 to a boost conversion unit Bn, where n is an integer greater than 1. The battery pack is composed of n series-connected batteries, that is, the batteries BAT1 to BATn are connected in series. There is a one-to-one correspondence between the n batteries and the n boost conversion units, that is, the battery BTA1 corresponds to the boost conversion unit B1, the battery BAT2 corresponds to the boost conversion unit B2, and so on, and the battery BATn corresponds to the boost conversion unit Bn. The internal structures and electrical performances of the respective boost conversion units are the same.

[0018] The connection relationship of the above-mentioned device is as follows: The voltage detection unit 0 is connected to the positive and negative electrodes of each battery, that is, the voltage detection unit 0 is respectively connected to the positive and negative electrodes of battery BAT1, battery BAT2, battery BAT3, … battery BATn. There is a one-to-one correspondence between the n batteries and the n boost conversion units. The positive electrode of battery BAT1 is connected to the positive input terminal of boost conversion unit B1, and the negative electrode of battery BAT1 is connected to the negative input terminal of boost conversion unit B1; the positive electrode of battery BAT2 is connected to the positive input terminal of boost conversion unit B2, and the negative electrode of battery BAT2 is connected to the negative input terminal of boost conversion unit B2, and so on. The positive electrode of battery BATn is connected to the positive input terminal of boost conversion unit Bn, and the negative electrode of battery BATn is connected to the negative input terminal of boost conversion unit Bn. The positive output terminals of boost conversion unit B1, boost conversion unit B2, …, boost conversion unit Bn are respectively connected to the positive electrode of the battery pack, that is, connected to the positive electrode of the first battery BAT1 in the battery pack. The negative output terminals of boost conversion unit B1, boost conversion unit B2, …, boost conversion unit Bn are respectively connected to the negative electrode of the battery pack, that is, connected to the negative electrode of the last battery BATn in the battery pack. The voltage detection circuit 0 is respectively connected to the control terminals of each boost conversion unit to send control instructions to each boost conversion unit.

[0019] The working principle of the voltage equalization circuit of this application is as follows: When the voltage detection unit detects that the voltage of a certain battery in the battery pack is unbalanced and needs to discharge it, it indicates that the boost circuit corresponding to this battery starts to work; the boost conversion unit boosts the current voltage signal of this battery to obtain a high voltage signal, and the voltage value of the high voltage signal is equal to the rated voltage value of the battery pack, and then loads the high voltage signal onto the battery pack for charging.

[0020] Among them, the voltage detection unit will first detect the voltage of each single battery in the battery pack, usually through a precise voltage measurement circuit, and can accurately read the voltage value of each battery. If the voltage detection unit detects that the voltage of a certain battery is significantly different from that of other batteries (that is, the voltage is unbalanced), it will trigger a signal indicating that voltage equalization operation is required. Once the voltage detection unit identifies the battery with unbalanced voltage, the voltage detection unit will send an instruction signal to the corresponding boost conversion unit, and this instruction signal will indicate the boost conversion unit to start working and boost the battery with lower voltage. After receiving the instruction, the corresponding boost conversion unit will start its internal boost circuit. The boost circuit will boost the current voltage signal of the battery with lower voltage until the voltage value of the output high voltage signal is equal to the rated voltage value of the battery pack. The boost process is usually achieved through power electronic devices (such as MOSFET, IGBT, etc.) and corresponding control circuits to ensure the efficiency and stability of the boost process.

[0021] When the high-voltage signal output by the boost conversion unit reaches the rated voltage value of the battery pack, it will load this high-voltage signal onto the battery pack. This loading process is usually achieved through a circuit connected between the boost conversion unit and the battery pack to ensure that the high-voltage signal can be safely and effectively transmitted to the battery pack. During the loading process, it is also necessary to ensure that the high-voltage signal does not damage the battery pack, so a series of protection measures need to be taken, such as overvoltage protection, overcurrent protection, etc.

[0022] During the entire voltage equalization process, the voltage detection unit continuously monitors the voltage changes of the battery pack and adjusts the output of the boost conversion unit as needed. If there are problems or abnormalities during the voltage equalization process, the voltage detection unit will send corresponding fault signals or warning signals for timely handling and repair. When the battery with a lower voltage is boosted and loaded onto the battery pack, the voltage of the entire battery pack will tend to be equalized. At this time, the voltage detection unit will detect the voltage distribution of the battery pack again to ensure that the voltages of all batteries are within the allowable range. If the voltages of all batteries reach the equalized state, the voltage equalization process is completed. Through the above steps, the voltage equalization of the batteries in the battery pack can be effectively achieved, improving the usage efficiency and safety of the battery pack.

[0023] In some embodiments of the present application, the open-circuit voltage can be used as a sign of whether the individual batteries are balanced with each other. If there is a significant difference between the voltage of a detected individual battery and that of other individual batteries, an equalization operation is required. If the capacities of the individual batteries are different, the capacity of the battery pack will be determined by the capacity of the individual battery that is depleted first. Therefore, ensuring the capacity balance between the individual batteries is crucial for improving the performance and lifespan of the entire battery pack. When the voltage of a certain battery cell exceeds a preset threshold, the equalization controller will trigger the equalization circuit. The equalization circuit is responsible for replenishing the battery cell with a higher voltage to the battery cell with a lower voltage by discharging to achieve the purpose of voltage equalization. When the battery management system (BMS) performs voltage detection, it will record the voltage values of each individual battery and calculate the average voltage or voltage range of the entire battery pack. If the voltage value of a certain individual battery exceeds the preset voltage range, or the difference from the average voltage exceeds a certain threshold (the threshold is usually set according to the battery type, battery pack design, and actual application requirements), then it can be considered that the voltage of this individual battery is significantly different from that of other individual batteries.

[0024] In some embodiments of the present application, refer to Figure 2 and Figure 3As shown in the figure, the circuit detection unit includes a BMS chip U1 and n voltage acquisition units, and the circuit structures and electrical performances of each voltage acquisition unit are the same. The BMS chip, that is, the Battery Management System chip, is an integrated circuit used to monitor, control, and protect the battery. By real-time monitoring parameters such as the voltage, current, and temperature of each single battery in the battery pack, the safety and performance stability of the battery are ensured.

[0025] Among them, the BMS chip is internally provided with n switches K1 to Kn, and there is a one-to-one relationship between the n switches and the n voltage acquisition circuits, that is, one switch is connected to one voltage acquisition circuit.

[0026] The connection relationship between the switch K1 and a corresponding voltage acquisition circuit will be described below:

[0027] The voltage acquisition circuit includes: a first capacitor C1, a first resistor R1, and a second resistor R2.

[0028] The first end of the switch K1 is connected to the first end of the first capacitor C1, and the second end of the switch K1 is connected to the second end of the first capacitor C1. The first end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the corresponding boost conversion unit, the second end of the first resistor R1 is connected to the positive electrode of the battery BAT1, the first end of the second resistor R2 is connected to the second end of the second capacitor C2, and the second end of the second resistor R2 is connected to the negative electrode of the battery BAT1.

[0029] In some embodiments of the present application, each boost conversion unit includes: a first MOS transistor Q1, a third resistor R3, a fourth resistor R4, a first diode D1, a second diode D2, a second capacitor C2, a third capacitor C3, a timer chip U2, a fifth resistor R5, a fourth capacitor C4, a second MOS transistor Q2, a transformer T1, and a third diode D3. The timer chip U2 can be used as a delay device, a trigger, or an oscillation element in circuits such as timers, pulse generators, and oscillation circuits. It has three basic operating modes: monostable, free-running (astable), and bistable (Schmitt trigger mode). The model of the timer chip can be NE555.

[0030] According to Figure 2 the shown circuit diagram, the voltage equalization circuit of the present application supports two equalization modes, that is, it can use the first resistor and the second resistor to discharge a certain battery to achieve the purpose of passive equalization, or it can use the boost conversion unit to boost the excess power of a certain battery and use the boosted voltage to charge the entire battery pack to achieve the purpose of active equalization.

[0031] The specific process is as follows: Discharge a certain battery through the first resistor and the second resistor, which is the basic implementation method of passive equalization. When it is detected that the voltage of a certain battery is too high, the redundant power can be released in the form of heat energy through the starting switch tube and the resistor, thereby reducing the voltage of the battery. This method is simple and direct, but the efficiency is low because the released energy is dissipated in the form of heat and cannot be reused.

[0032] The subsequent boost conversion unit can implement the function of active equalization. It can transfer the power in the high-voltage battery to the low-voltage battery or charge the entire battery pack. This method is more efficient because it can transfer the power from the high-voltage battery to the low-voltage battery, avoiding energy waste.

[0033] This application can combine the hybrid strategies of passive equalization and active equalization, and can flexibly select which equalization method to use according to the actual situation. For example, when the voltage difference of the battery pack is small (the voltage difference between the voltage value of a certain battery and the average voltage value is less than the threshold), active equalization can be mainly relied on for fine-tuning to achieve more precise voltage balance. And when the voltage difference of the battery pack is large (the voltage difference between the voltage value of a certain battery and the average voltage value is greater than the threshold) or it is necessary to quickly reduce the voltage of a certain battery, passive equalization can be started to accelerate the voltage equalization process.

[0034] See Figure 3 As shown, the connection relationship between the following boost conversion unit B1 and the corresponding voltage acquisition circuit and the battery BAT1 is as follows:

[0035] The drain of the first MOS transistor Q1 is connected to the positive electrode of the battery BAT1, the gate of the first MOS transistor Q1 is connected to the first end of the first resistor R1, and the source of the first MOS transistor Q1 is respectively connected to the first end of the third resistor R3, the positive power supply pin VCC of the timer chip U2, and the reset pin RST. The second end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4, the anode of the first diode D1, and the discharge pin DIS of the timer chip U2. The second end of the fourth resistor R4 is connected to the cathode of the second diode D2. The cathode of the first diode D1 is respectively connected to the threshold pin THRS of the timer chip U2, the trigger pin TRIG of the timer chip U2, the anode of the second diode D2, and the first end of the second capacitor C2. The second end of the second capacitor C2 is connected to the negative electrode of the battery BAT1.

[0036] The first terminal of the third capacitor C3 is connected to the control voltage pin CV of the timer chip U2, and the second terminal of the third capacitor C3 is connected to the negative electrode of the battery BAT1. The ground pin GND of the timer chip U2 is connected to the negative electrode of the battery BAT1. The output pin OUT of the timer chip U2 is connected to the first terminal of the fifth resistor R5, the second terminal of the fifth resistor R5 is connected to the gate of the second MOS transistor Q2, the source of the second MOS transistor is connected to the negative electrode of the battery BAT1, and the drain of the second MOS transistor is connected to the negative input pin 2 of the transformer T1. The positive input pin of the transformer T1 is respectively connected to the reset pin RST and the positive power supply pin VCC of the timer chip U2. The fourth capacitor C4 is connected across the positive input pin 1 and the negative input pin 2 of the transformer T1. The positive output pin 3 of the transformer T1 is connected to the anode of the third diode D3, the cathode of the third diode D3 is connected to the positive electrode of the battery BAT1, and the negative output pin 4 of the transformer T1 is connected to the negative electrode of the battery BATn.

[0037] Combined Figure 2 with Figure 3 the circuit diagram of the voltage equalization circuit, its working process can include:

[0038] All switches (K1 to Kn) are default in the off state. When the BMS chip U1 detects voltage imbalance in the battery BAT1 and needs to discharge it, it controls the switch K1 to close. At this time, the first capacitor C1 forms a voltage dividing circuit with the battery BAT1 through the first resistor R1 and the second resistor R2.

[0039] The voltage acquisition circuit can measure the voltage value of the battery BAT1 by measuring the voltage across the first capacitor C1. After the voltage acquisition is completed, the BMS chip U1 decides to perform a boost operation on the battery BAT1 and sends a control instruction to the timer chip U2 in the boost conversion unit B1. The positive power supply pin VCC and the reset pin RST of the timer chip U2 are powered through the source of the first MOS transistor Q1 and the third resistor R3. When the voltage at the first end of the first resistor R1 (connected to the gate of the first MOS transistor Q1) reaches a certain threshold, the first MOS transistor Q1 conducts. After the first MOS transistor Q1 conducts, the timer chip U2 is powered and starts to work. The timer chip U2 controls the conduction and cutoff of the second MOS transistor Q2 through the internal logic circuit. When the output pin OUT of the timer chip U2 outputs a high level, the second MOS transistor Q2 conducts and the transformer T1 starts to work. The positive input pin of the transformer T1 is connected to the positive electrode of the battery BAT1 through the source of the first MOS transistor Q1 and the third resistor R3, and the negative input pin is connected to the negative electrode of the battery BAT1 through the second MOS transistor Q2. The transformer T1 boosts the voltage of the battery BAT1 and outputs it through the positive output pin 3 and the negative output pin 4. The boosted voltage is output to the positive electrode of the battery BAT1 through the positive and negative electrodes of the third diode D3, forming a closed loop. The negative output pin 4 of the transformer T1 is usually connected to the negative electrode of other circuits or the battery BATn to provide additional power or for energy recovery.

[0040] The timer chip U2 controls the boost conversion period and duty cycle through the internal logic circuit and peripheral circuits (such as the third resistor R3, the fourth resistor R4, the first diode D1, the second diode D2, etc.). The output pin OUT of the timer chip U2 periodically outputs high and low levels, thereby controlling the conduction and cutoff of the second MOS transistor Q2 and realizing the periodic operation of the boost conversion.

[0041] In some embodiments of the present application, each boost conversion unit is arranged on the circuit board, and the circuit board is connected to the voltage detection unit and the battery in a pluggable manner.

[0042] Among them, due to the use of a pluggable connection method, when a certain boost conversion unit fails or needs to be upgraded, it can be easily pulled out from the circuit board and a new unit can be inserted. This not only simplifies the maintenance process but also reduces the maintenance cost. The pluggable design allows for flexible configuration of the number and position of the boost conversion units according to actual needs. For example, when the scale of the battery pack expands, more boost conversion units can be easily added to maintain voltage balance. During the maintenance process, since there is no need to weld or cut the circuit board, the risk of damage to the circuit board and other electronic components is reduced.

[0043] The present application has the following beneficial effects:

[0044] Traditional voltage equalization methods usually use resistors for discharging. This method is not only inefficient but also generates a large amount of heat, affecting the stability and safety of the battery pack. In this solution, the boost conversion unit directly boosts the voltage signal of the battery that needs to be discharged to the rated voltage value of the battery pack and loads it onto the battery pack for charging, realizing an equalization process without resistor discharge. This improvement greatly reduces the heat generation of the system and improves the stability and safety of the system.

[0045] Electric energy recovery and improved utilization efficiency: Under the action of the boost conversion unit, the electric energy of the battery that originally needed to be discharged is converted into a high-voltage signal and loaded onto the battery pack for charging. In this process, the electric energy that might have been wasted is effectively recovered and reused, significantly improving the utilization efficiency of electric energy. This feature is particularly important in the context of increasingly tight energy.

[0046] Flexibility and scalability: This solution adopts a modular design, with each battery corresponding to a boost conversion unit, making the system highly flexible and scalable. Regardless of how the scale of the battery pack changes, simply increasing or decreasing the number of boost conversion units accordingly can achieve voltage equalization management.

[0047] The electronic device provided in the embodiments of this application includes, but is not limited to, communication devices, terminal devices, computer devices, etc. In addition to the above voltage equalization circuit, the electronic device may further include: a housing for accommodating each component, a display screen, and an input device (such as a keyboard, mouse, or touch screen), etc.

[0048] The above-described embodiments do not constitute a limitation on the protection scope of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the above embodiments shall be included within the protection scope of this technical solution.

Claims

1. A voltage equalization circuit, applied to a battery pack consisting of n batteries connected in series, characterized in that: include: A voltage detection unit and n boost conversion units, where n is an integer greater than 1; Wherein, the voltage detection unit is connected to the positive and negative electrodes of each battery, the n batteries and the n boost conversion units are in a one-to-one correspondence, the positive input end of the boost conversion unit is connected to the positive electrode of the corresponding battery, and the negative input end of the boost conversion unit is connected to the negative electrode of the corresponding battery; the positive output end of the boost conversion unit is connected to the positive electrode of the battery pack, and the negative output end of the boost conversion unit is connected to the negative electrode of the battery pack; the voltage detection unit is connected to each boost conversion unit respectively; The voltage detection unit is used to instruct the boost conversion circuit corresponding to a battery to start working when it detects that the voltage of a battery in the battery pack is unbalanced and needs to be discharged; The boost conversion unit is used to boost the current voltage signal of the battery to obtain a high voltage signal, the voltage value of the high voltage signal is equal to the rated voltage value of the battery pack, and load the high voltage signal to the battery pack for charging.

2. The circuit according to claim 1, characterized in that The voltage detection unit includes: a BMS chip and n voltage collection circuits, the BMS chip has n switches built in, and the n switches and the n voltage collection circuits are in a one-to-one relationship; Each voltage acquisition circuit includes: a first capacitor, a first resistor, and a second resistor; In a pair of switches and voltage acquisition circuits having a corresponding relationship, the first end of the switch is connected to the first end of the first capacitor, and the second end of the switch is connected to the second end of the first capacitor; the first end of the first resistor is respectively connected to the first end of the first capacitor and the corresponding boost conversion unit, the second end of the first resistor is connected to the positive electrode of the corresponding battery, the first end of the second resistor is connected to the second end of the second resistor, and the second end of the second resistor is connected to the negative electrode of the corresponding battery.

3. The circuit according to claim 2, characterized in that Each boost conversion unit includes: a first MOS tube, a third resistor, a fourth resistor, a first diode, a second diode, a second capacitor, a third capacitor, a timer chip, a fifth resistor, a fourth capacitor, a second MOS tube, a transformer, and a third diode; The connection relationship between a set of boost conversion units, a voltage collection circuit, and a battery having a corresponding relationship is: The drain of the first MOS tube is connected to the positive electrode of the corresponding battery, the gate of the first MOS tube is connected to the first end of the first resistor, and the source of the first MOS tube is respectively connected to the first end of the third resistor, the positive power pin of the timer chip, and the reset pin; The second end of the third resistor is respectively connected to the first end of the fourth resistor, the anode of the first diode, and the discharge pin of the timer chip; The second end of the fourth resistor is connected to the cathode of the second diode; The cathode of the first diode is respectively connected to the threshold pin of the timer chip, the trigger pin of the timer chip, the anode of the second diode, and the first end of the second capacitor; The second end of the second capacitor is connected to the negative electrode of the corresponding battery; A first end of the third capacitor is connected to a control voltage pin of the timer chip, and a second end of the third capacitor is connected to a negative electrode of a corresponding battery; The ground pin of the timer chip is connected to the negative electrode of the corresponding battery; The output pin of the timer chip is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the gate of the second MOS tube, and the source of the second MOS tube is connected to the negative electrode of the corresponding battery; the drain of the second MOS tube is connected to the negative input pin of the transformer, the positive input pin of the transformer is respectively connected to the reset pin and the positive power pin of the timer chip, and the fourth capacitor is connected between the positive input pin and the negative input pin of the transformer; the positive output pin of the transformer is connected to the anode of the third diode, the cathode of the third diode is connected to the positive electrode of the first battery in the battery pack, and the negative output pin of the transformer is connected to the negative electrode of the last battery in the battery pack.

4. The circuit according to claim 1, 2 or 3, characterized in that: Each boost conversion unit is arranged on a circuit board, and the circuit board is connected to the voltage detection unit and the battery in a pluggable manner.

5. An electronic device, characterized in that: It comprises any one of the voltage equalization circuits according to claims 1 to 4, and a battery pack.

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