A battery pack voltage equalization control system, method and battery pack

Abstract

The application discloses a battery pack voltage equalization control system, method and battery pack. The control method comprises a charging equalization control process and / or a discharging equalization control process. The charging equalization control process comprises detecting the voltage of each battery module, obtaining a battery module with the highest voltage, controlling the battery module with the highest voltage to bypass and controlling the remaining battery modules to continue dynamic equalization charging. The discharging equalization control process comprises detecting the voltage of each battery module in a discharging state, obtaining a battery module with the highest voltage, controlling the battery module with the highest voltage to increase the discharging current of a battery cell for discharging, and controlling the battery cells of the remaining battery modules to dynamically equalize discharging at a normal discharging current.

Description

Technical Field

[0001] This invention relates to the field of voltage equalization control technology, specifically to a battery pack voltage equalization control system, method, and battery pack. Background Technology

[0002] With the widespread application of lithium-ion batteries in electric vehicles, energy storage systems, and portable electronic devices, the performance and safety of lithium battery packs are receiving increasing attention. In practical applications, due to differences in manufacturing processes, usage environments, and aging levels, the voltage and capacity of individual cells within a battery pack often exhibit inconsistencies, a phenomenon known as "cell voltage imbalance." This imbalance directly affects the overall performance of the battery pack. Especially during charging and discharging, cells with lower voltages reach their charge / discharge cutoff voltage earlier, while cells with higher voltages cannot fully utilize their capacity, leading to a decrease in the overall usable capacity of the battery pack, creating a "weakest link" effect.

[0003] Currently, battery pack balancing technologies are mainly divided into two categories: passive balancing and active balancing. Passive balancing technology achieves voltage equalization by connecting energy-dissipating resistors in parallel with individual battery cells, dissipating the energy of cells with higher voltages as heat. While this method is simple in structure and low in cost, it suffers from drawbacks such as high energy loss, slow balancing speed, and the inability to perform balancing only in a static state. Especially during dynamic charging and discharging, the battery pack lacks sufficient resting time for balancing, leading to the gradual accumulation of imbalance problems and severely impacting the battery pack's lifespan and energy efficiency.

[0004] Active balancing technology improves energy efficiency by transferring energy from high-voltage cells to low-voltage cells. Existing active balancing solutions include inductive, capacitive, and transformer topologies, but they typically suffer from problems such as complex circuitry, difficult control, high cost, and difficulty in achieving dynamic real-time balancing. Summary of the Invention

[0005] To address the shortcomings of existing technologies, a battery pack voltage balancing control system, method, and battery pack are provided.

[0006] To achieve the above objectives, the present invention provides a battery pack equalization control method, including a charging equalization control process and / or a discharging equalization control process; wherein, the charging equalization control process includes: detecting the voltage of each battery module to identify the battery module with the highest voltage; controlling the battery module with the highest voltage to bypass and controlling the remaining battery modules to continue dynamic equalization charging; the discharging equalization control process includes: detecting the voltage of each battery module in a discharging state to identify the battery module with the highest voltage; controlling the battery module with the highest voltage to increase the discharge current of its individual cells for discharging and controlling the individual cells of the remaining battery modules to perform dynamic equalization discharging at normal discharge current.

[0007] According to one embodiment of the present invention, during the charging equalization control process, detecting the voltage of each battery module in the charging state includes: at the beginning of charging, first detecting the voltage of all battery modules in the battery pack to identify the battery module with the highest voltage; then, every preset first interval, detecting the voltage of the battery modules in the bypass state and all other battery modules that continue to charge; after each round of detection is completed, identifying the battery module with the highest voltage in this round of detection.

[0008] According to one embodiment of the present invention, during the discharge equalization control process, detecting the voltage of each battery module in the discharge state includes: detecting the battery module with the highest voltage among all discharged battery modules at preset second intervals, and after each round of detection is completed, knowing the battery module with the highest voltage in this round of detection.

[0009] According to one embodiment of the present invention, dynamic equalization charging includes: during charging, controlling the charging of battery cells with lower voltage in the battery module, pausing the charging of battery cells with higher voltage in the battery module, and charging the two battery cells simultaneously when their voltages are equal.

[0010] According to one embodiment of the present invention, dynamic equalization discharge includes: during discharge, controlling the higher voltage battery cell in the battery module to discharge, pausing the discharge of the lower voltage battery cell in the battery module, and the discharge current of the higher voltage battery cell being equal to half of the load current; when the voltages of two battery cells are equal, the two battery cells discharge simultaneously, and the discharge current of each battery cell is equal to half of the load current.

[0011] This invention also provides a battery pack voltage equalization control system, comprising: a main control chip, multiple battery modules, multiple switching units, and multiple unidirectional conduction units; each battery module has a charging positive terminal, a charging negative terminal, a discharging negative terminal, and a discharging positive terminal; the main control chip is electrically connected to the multiple battery modules and the multiple switching units, a switching unit is connected between the charging negative and charging positive terminals of two adjacent battery modules, and a unidirectional conduction unit is connected between the discharging positive and discharging negative terminals of two adjacent battery modules; wherein, when the main control chip receives a charging signal, the main control chip controls the multiple switching units to close and the multiple unidirectional conduction units to open, and then the main control chip detects the voltage of each battery module to identify the battery module with the highest voltage, controls the battery module with the highest voltage to bypass, and controls the remaining battery modules to dynamically equalize charging; when the main control chip receives a discharging signal, the main control chip controls the multiple switching units to open and the multiple unidirectional conduction units to close, and then the main control chip detects the voltage of each battery module in a discharging state to identify the battery module with the highest voltage, controls the battery module with the highest voltage to increase the discharge current of its individual cells for discharging, and controls the individual cells of the remaining battery modules to dynamically equalize discharge with normal discharge current.

[0012] According to one embodiment of the present invention, when the main control chip receives a charging signal, at the beginning of charging, the main control chip first detects the voltage of all battery modules to determine the battery module with the highest voltage; then, every preset first interval, the main control chip detects the voltage of the battery modules in bypass state and all other battery modules that continue to charge. After each round of detection is completed, the battery module with the highest voltage in this round of detection is determined.

[0013] According to one embodiment of the present invention, when the main control chip receives a discharge signal, it detects the battery module with the highest voltage among all the discharged battery modules at a preset second interval. After each round of detection is completed, the main control chip knows the battery module with the highest voltage in this round of detection.

[0014] According to one embodiment of the present invention, each battery module includes a switching element, a first unidirectional conducting element, a second unidirectional conducting element, a first battery cell, and a second battery cell; one end of the switching element is connected to the charging positive terminal, the positive terminal of the first battery cell, and the positive terminal of the second unidirectional conducting element, respectively, and the other end is connected to the charging negative terminal, the negative terminal of the second battery cell, and the negative terminal of the first unidirectional conducting element; the switching element is also connected to a main control chip; the negative terminal of the first battery cell is connected to the positive terminal of the first unidirectional conducting element and the discharging negative terminal, respectively; the positive terminal of the second battery cell is connected to the negative terminal of the second unidirectional conducting element and the discharging positive terminal, respectively. When the main control chip receives a charging signal, after determining the battery module with the highest voltage, the main control chip controls the battery module with the highest voltage. When the switching elements in the module are closed, the battery module with the highest voltage is bypassed. The main control chip also controls the switching elements in the remaining battery modules to open, and the first and second battery cells are connected in parallel to charge the remaining battery modules. When the main control chip receives a discharge signal, it identifies the battery module with the highest voltage and controls the switching elements in that module to close. The first and second battery cells are connected in series, causing the first and second battery cells in the highest voltage battery module to increase their discharge current and discharge. The main control chip also controls the switching elements in the remaining battery modules to open, and the first and second battery cells are connected in parallel, allowing the first and second battery cells in the remaining battery modules to discharge with normal current.

[0015] The present invention also provides a battery pack including the above-described battery pack voltage equalization control system.

[0016] The beneficial effects of this invention are as follows: During the charging phase, the battery module with the highest voltage is bypassed, while the remaining battery modules are dynamically and evenly charged, avoiding overcharging or undercharging of some battery modules and ensuring that all battery modules gradually reach voltage balance during the charging process. During the discharging phase, when the battery cell with the highest voltage increases its discharge current, the battery module with the highest voltage will preferentially release energy, increasing the discharge rate. As discharge progresses, its voltage gradually decreases. At this time, the main control chip continuously monitors the voltage changes of each module and adjusts the discharge strategy in real time, causing the remaining battery modules to gradually increase their discharge capacity. Ultimately, this achieves a coordinated voltage decrease in all battery modules during the discharge process, effectively improving the overall discharge efficiency and energy utilization of the battery pack, while preventing negative impacts on the performance of the entire battery pack due to abnormal voltage in individual modules. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a circuit diagram of the battery pack voltage equalization control system in Example 1;

[0019] Figure 2 This is a charging flowchart of the control system in Embodiment 1;

[0020] Figure 3 This is a discharge flowchart of the control system in Example 1;

[0021] Figure 4 This is a circuit diagram of the battery module in Example 1;

[0022] Figure 5 This is a schematic diagram of the battery module in bypass mode in Example 1;

[0023] Figure 6 This is a schematic diagram of the battery module in the first embodiment being in a dynamic equalization charging state;

[0024] Figure 7 This is a schematic diagram of the battery module in Example 1 being in a state where the individual battery cells are increasing their discharge current.

[0025] Figure 8 This is a schematic diagram of the battery module in the first embodiment being in a dynamic equalization discharge state.

[0026] Explanation of reference numerals in the attached figures

[0027] 1. Main control chip;

[0028] 2. Battery module; 21. Switching element; 22. First unidirectional conducting element; 23. Second unidirectional conducting element; 24. First battery cell; 25. Second battery cell;

[0029] 3. Switching unit;

[0030] 4. Unidirectional conduction unit. Detailed Implementation

[0031] The following drawings disclose several embodiments of the present invention. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0032] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, such a combination should be considered nonexistent and not within the scope of protection claimed by this invention.

[0033] Example 1

[0034] Please refer to Figures 1-3 , Figure 1 This is the circuit diagram for the battery pack balancing control system. Figure 2 The charging flowchart for the control system. Figure 3 This is a discharge flowchart of the control system. This embodiment provides a battery pack voltage balancing control system, which includes a main control chip 1, multiple battery modules 2, multiple switching units 3, and multiple unidirectional conduction units 4. Each battery module 2 has a charging positive terminal, a charging negative terminal, a discharging positive terminal, and a discharging negative terminal, with the discharging positive and negative terminals of the battery module 2 in opposite positions. During connection, the main control chip 1 is electrically connected to the multiple battery modules 2 and the multiple switching units 3. A switching unit 3 is connected between the charging negative and charging positive terminals of two adjacent battery modules 2, and a unidirectional conduction unit 4 is connected between the discharging positive and discharging negative terminals of two adjacent battery modules 2.

[0035] When the main control chip 1 receives a charging signal, it controls multiple switching units 3 to close. At this time, the charging terminals of each battery module 2 are connected in series, meaning the positive charging terminal of one battery module 2 is connected in series with the negative charging terminal of an adjacent battery module 2. Multiple unidirectional conducting units 4 are reverse-biased and cut off, making the discharging terminal of each battery module 2 open-circuit, meaning the positive discharging terminal of one battery module 2 is disconnected from the negative discharging terminal of an adjacent battery module 2. Then, the main control chip 1 detects the voltage of each battery module 2 and, based on the detected voltage, controls the battery module 2 with the highest voltage to bypass, while the remaining battery modules 2 undergo dynamic equalization charging.

[0036] When the main control chip 1 receives a discharge signal, it controls multiple switching units 3 to disconnect. At this time, the load current causes the unidirectional conduction unit 4 to close in the forward direction, thereby connecting the discharge terminals of multiple battery modules 2 in series. That is, the positive discharge terminal of one battery module 2 is connected in series with the negative discharge terminal of the adjacent battery module 2. Then, the main control chip 1 detects the voltage of each battery module 2 and, based on the detected voltage of each battery module 2, controls the battery cells of the battery module 2 with the highest voltage to increase the discharge current for rapid discharge, while the battery cells of the remaining battery modules 2 are discharged evenly with normal discharge current.

[0037] Thus, when the main control chip 1 receives a charging signal, it controls multiple switching units 3 to close, connecting the charging terminals of multiple battery modules 2. Then, the main control chip 1 detects the voltage of each battery module 2 and controls the battery module 2 with the highest voltage to bypass, prioritizing charging the other battery modules 2 with lower voltages to achieve voltage balance among the multiple battery modules 2. Simultaneously, the other battery modules 2 with lower voltages are charged evenly, ensuring voltage balance among the individual battery cells within each battery module 2 and preventing overcharging. When the main control chip 1 receives a discharging signal, it controls multiple switching units 3 to open, connecting the discharging terminals of multiple battery modules 2. Then, the main control chip 1 detects the voltage of each battery and controls the battery cells in the battery module 2 with the highest voltage to increase the discharge current, causing the battery module 2 with the highest voltage to discharge more intensely, rapidly reducing the voltage of the battery module 2 and achieving voltage balance among the multiple battery modules 2. The battery cells in the other battery modules 2 undergo dynamic equalization discharge with normal discharge current, ensuring smooth and even discharge among the battery cells within each battery module 2, thereby achieving voltage balance among the battery cells within each battery module 2 and preventing over-discharge.

[0038] In this example, switching unit 3 is an NMOS transistor, and unidirectional conduction unit 4 is a diode. During connection, the gate of switching unit 3 is connected to the main control chip 1, the drain of switching unit 3 is connected to the negative charging terminal of one battery module 2, and the source of switching unit 3 is connected to the positive charging terminal of another battery module 2. The positive terminal of unidirectional conduction unit 4 is connected to the positive discharging terminal of one battery module 2, and the negative terminal of unidirectional conduction unit 4 is connected to the negative discharging terminal of another battery module 2. When the main control chip 1 receives a charging signal, it sends a high-level signal to the gate of switching unit 3, causing switching unit 3 to close and conduct; when the main control chip 1 receives a discharging signal, it sends a low-level signal to the gate of switching unit 3, causing switching unit 3 to turn off.

[0039] Furthermore, in practical applications, the main control chip 1 is electrically connected to the host computer. When the main control chip 1 receives a charging signal from the host computer, it controls multiple switch units 3 to close, causing the charging terminals of multiple battery modules 2 to be connected in series. Then, the main control chip 1 detects the voltage of each battery module 2, bypasses the battery module 2 with the highest voltage, and controls the remaining battery modules 2 to continue charging.

[0040] When battery module 2 is bypassed, the voltage across it approaches zero. At this time, the total voltage output from the external charger is distributed to the remaining unbypassed battery modules 2, causing the voltage of the highest-voltage battery module 2 to stop rising, while the lower-voltage battery modules 2 receive higher charging voltages, resulting in larger charging currents and faster voltage increases. The remaining battery modules 2 continue charging, and the individual battery cells within each module are charged evenly, further achieving voltage balance within the battery modules 2.

[0041] Furthermore, since the voltage of each battery module 2 changes continuously during the charging process, the main control chip 1 needs to continuously detect the voltage of each battery module 2 and dynamically adjust the working state of each battery module 2 based on the real-time detected voltage data.

[0042] Specifically, when the main control chip 1 receives a charging signal, in the initial charging stage, it detects the voltage of all battery modules 2 to identify the battery module 2 with the highest voltage. Then, after a preset first interval, the main control chip 1 detects the voltage of all other battery modules 2 that are either in bypass mode or continuing to charge, thus identifying the battery module 2 with the highest voltage in each round of detection. In this example, the preset first interval is 50ms, and the main control chip 1 detects the voltage of the battery modules 2 every 50ms. The main control chip 1 compares the voltage of each battery module 2 and then selects the battery module 2 with the highest voltage. In this example, the main control chip 1 uses a bubble sort method to select the battery module 2 with the highest voltage. Then, the main control chip 1 bypasses the battery module 2 with the highest voltage and continues charging the remaining battery modules 2.

[0043] Thus, when the voltage of a previously charging battery module 2 rises to its highest voltage, the main control chip 1 immediately short-circuits it, while reconnecting the previously bypassed battery module 2 to the charging circuit. This continuous voltage monitoring and mode switching mechanism ensures that throughout the entire charging cycle, only the battery module 2 with the highest voltage is bypassed, while the remaining battery modules 2 are charged at appropriate voltages and currents. This effectively avoids uneven charging caused by excessively high voltages in individual battery modules 2, thereby improving the overall charging efficiency and lifespan of the battery pack. Simultaneously, during mode switching, the main control chip 1 precisely controls the on / off timing of the switching unit 3 to ensure the stability of the charging circuit, preventing sudden current changes or voltage fluctuations from impacting the battery modules 2 and the charging system.

[0044] During charging, the main control chip 1 checks whether each battery module 2 has completed charging. If any battery module 2 has not completed charging, the main control chip 1 returns to the step of detecting the voltage of each battery module 2 to determine the battery module 2 with the highest voltage, and the main control chip 1 controls the completed battery module 2 to bypass, allowing the remaining battery modules 2 that have not completed charging to continue charging. If the main control chip 1 detects that each battery module 2 has completed charging, the main control chip 1 determines that charging is complete and controls multiple battery modules 2 to stop charging.

[0045] When the main control chip 1 receives a discharge signal, multiple switching units 3 are disconnected, causing the discharge terminals of multiple battery modules 2 to discharge in series. Then, the main control chip 1 detects the voltage of each battery module 2, controls the battery cell of the battery module 2 with the highest voltage to increase the discharge current, and controls the battery cells of the remaining battery modules 2 to discharge evenly with normal discharge current.

[0046] When the discharge current of the individual cells in battery module 2 increases, the voltage drop rate of battery module 2 increases. This allows the battery module 2 with the highest voltage to rapidly discharge, quickly reducing its voltage to match that of the other lower-voltage modules. The individual cells in the remaining battery modules 2 discharge at normal current, resulting in a slower voltage drop rate. Furthermore, when the remaining battery modules 2 discharge at normal current, the individual cells within each module discharge evenly, achieving voltage balance within battery module 2.

[0047] Similarly, to prevent over-discharge of individual battery modules 2, the main control chip 1 detects the voltage of each battery module 2 at preset second intervals. In this example, the preset second interval is 50ms, and the main control chip 1 detects the voltage of each battery module 2 every 50ms. Then, the main control chip 1 compares the voltages of each battery module 2 and selects the battery module 2 with the highest voltage. In this example, the main control chip 1 uses a bubble sort method to select the battery module 2 with the highest voltage. Then, the main control chip 1 controls the battery cells of the battery module 2 with the highest voltage to increase the discharge current for discharge, while controlling the battery cells of the other battery modules 2 to discharge at normal discharge current.

[0048] As the discharge process continues, when the battery cell of the battery module 2 with the highest voltage initially increases its discharge current, causing battery module 2 to discharge rapidly to a voltage close to that of the other battery modules 2, the main control chip 1 will trigger the detection mechanism again to re-compare the real-time voltages of all battery modules 2. At this point, a new battery module 2 with the highest voltage may appear. The main control chip 1 will immediately adjust the operating state of each battery module 2, causing the battery cell of the new highest voltage battery module 2 to increase its discharge current to improve the discharge speed, while the battery cells of the other battery modules 2 maintain or switch to normal discharge current for balanced discharge, and this cycle repeats. Through this dynamic adjustment method, the overall discharge efficiency can be avoided due to the excessively high voltage of a single battery module 2, and the damage to any battery module 2 due to over-discharge can be prevented. At the same time, it ensures that the voltage of each battery module 2 remains in a relatively balanced state throughout the discharge process, effectively improving the discharge stability and service life of the battery modules 2.

[0049] During the discharge process, the main control chip 1 detects whether each battery module 2 has completed discharging. If any battery module 2 has not completed discharging, the main control chip 1 returns to the step of detecting the voltage of each battery module 2 to determine the battery module 2 with the highest voltage, and controls the battery module 2 that has completed discharging to stop discharging, while controlling the remaining battery modules 2 to continue discharging. When the main control chip 1 detects that each battery module 2 has completed discharging, the main control chip 1 controls multiple battery modules 2 to stop discharging.

[0050] Please refer to Figure 4 , Figure 4This is a circuit diagram of the battery module. Further, the battery module 2 includes a switching element 21, a first unidirectional conducting element 22, a second unidirectional conducting element 23, a first battery cell 24, and a second battery cell 25. During connection, one end of the switching element 21 is connected to the charging positive terminal, the positive terminal of the first battery cell 24, and the positive terminal of the second unidirectional conducting element 23, respectively; its other end is connected to the charging negative terminal, the negative terminal of the second battery cell 25, and the negative terminal of the first unidirectional conducting element 22. The switching element 21 is also connected to the main control chip 1. The negative terminal of the first battery cell 24 is connected to both the positive terminal and the discharging negative terminal of the first unidirectional conducting element 22; the positive terminal of the second battery cell 25 is connected to both the negative terminal and the discharging positive terminal of the second unidirectional conducting element 23.

[0051] In this example, switching element 21 is an NMOS transistor, and the first unidirectional conducting element 22 and the second unidirectional conducting element 23 are both diodes. During connection, the gate of switching unit 3 is connected to the main control chip 1, the drain of switching unit 3 is connected to the charging positive terminal, the positive terminal of the first battery cell 24, and the positive terminal of the second unidirectional conducting element 23, respectively, and the source of switching unit 3 is connected to the charging negative terminal, the negative terminal of the second battery cell 25, and the negative terminal of the first unidirectional conducting element 22, respectively. When the main control chip 1 sends a high-level signal to switching unit 3, switching unit 3 is turned on; when the main control chip 1 sends a low-level signal to switching unit 3, switching unit 3 is turned off.

[0052] Please refer to Figure 5 , Figure 5 This diagram illustrates the battery module in bypass mode. During charging, when the main control chip 1 controls the battery module 2 to bypass, the main control chip 1 controls the switch element 21 to close, at which point the switch element 21 is in the conducting state. With the switch element 21 conducting, it provides a low-impedance path for the current. The charging current output by the charger enters from the positive terminal of the battery module 2, passes through the switch element 21, and then exits from the negative terminal of the battery module 2. At this time, no current flows through the first battery cell 24 and the second battery cell 25 in the battery module 2; therefore, the first battery cell 24 and the second battery cell 25 are not charged. Thus, by closing the switch element 21, a very low-impedance "short-circuit" path in parallel with the battery is established for the charging current, so that the battery module 2 no longer bears a significant voltage division function in the charging series circuit, thereby redistributing the charging energy to the other battery modules 2.

[0053] Please refer to Figure 6 , Figure 6This diagram illustrates the battery module in a dynamic equalization charging state. When the main control chip 1 controls the battery module 2 to dynamically equalize charge, the main control chip 1 controls the switch element 21 to open. At this time, the first battery cell 24 and the second battery cell 25 are connected in parallel through the first unidirectional conducting element 22 and the second unidirectional conducting element 23. When the voltage of the first battery cell 24 is higher than the voltage of the second battery cell 25, the potential of the negative terminal of the first battery cell 24 (i.e., the positive terminal of the first unidirectional conducting element 22) is lower, causing the first unidirectional conducting element 22 to fail to meet the conduction condition. The first unidirectional conducting element 22 is then cut off, preventing the charging circuit of the first battery cell 24 from closing and thus preventing the first battery cell 24 from charging. However, because the voltage of the second battery cell 25 is lower, the potential of the positive terminal of the second battery cell 25 (i.e., the negative terminal of the second unidirectional conducting element 23) is lower, satisfying the conduction condition of the second unidirectional conducting element, causing the second unidirectional element to conduct. Thus, the charging current output by the charger is input from the positive terminal of the charging module, then flows through the second unidirectional conducting element 23 and into the positive terminal of the second battery cell 25, then outputs from the negative terminal of the second battery cell 25 to the negative terminal of the charging module, and finally outputs from the negative terminal of the charging module, thus forming a complete electrical circuit for the second battery cell 25 and charging the second battery cell 25.

[0054] As charging progresses, the voltage of the second battery cell 25 gradually increases. When the voltage of the second battery cell 25 is the same as that of the first battery cell 24, the negative potentials of the first unidirectional conducting element 22 and the second unidirectional conducting element 23 are close. At this time, both the first unidirectional conducting element 22 and the second unidirectional conducting element 23 meet the conduction conditions and conduct simultaneously. The charging current output by the charger simultaneously charges the first battery cell 24 and the second battery cell 25, ensuring that the first battery cell 24 and the second battery cell 25 always maintain a high degree of consistency, achieving the effect of balanced charging of the first battery cell 24 and the second battery cell 25.

[0055] When the voltage of the second battery cell 25 is higher than the voltage of the first battery cell 24, the positive terminal of the second battery cell 25 (i.e., the negative terminal of the second unidirectional conducting element 23) has a higher potential. At this time, the second unidirectional conducting element 23 is cut off, and the second battery cell 25 cannot be charged. Since the voltage of the second battery cell 25 is lower (i.e., the negative terminal of the first unidirectional conducting element 22 has a lower potential), the conduction condition of the first unidirectional conducting element 22 is met, causing the charging circuit of the first battery cell 24 to close, and the first battery cell 24 to charge.

[0056] The voltage of the first battery cell 24 gradually increases as it is charged. When the voltage of the first battery cell 24 is equal to that of the second battery cell 25, the negative potential of the first unidirectional conducting element 22 and the negative potential of the second unidirectional conducting element 23 are close. At this time, both the first unidirectional conducting element 22 and the second unidirectional conducting element 23 meet the conduction conditions. The first unidirectional conducting element 22 and the second unidirectional conducting element 23 conduct simultaneously, and the charging current output by the charger charges both the first battery cell 24 and the second battery cell 25 at the same time.

[0057] Through the aforementioned dynamic adjustment mechanism, during dynamic equalization charging, the charging current of battery module 2 always preferentially flows to the battery cells with lower voltage until their voltages converge, at which point they charge together. This effectively avoids overcharging or undercharging caused by voltage imbalances among battery cells. This adaptive charging path switching method based on unidirectional conduction elements eliminates the need for complex voltage sampling feedback adjustment algorithms. It achieves dynamic equalization among battery cells solely through the characteristics of the hardware circuit, significantly improving the safety and reliability of the charging process of battery module 2 while simplifying the complexity and cost of circuit design.

[0058] Please refer to Figure 7 , Figure 7 This diagram illustrates the battery module in a state where the individual battery cells are increasing their discharge current. During discharge, the main control chip 1 controls the switch element 21 to close. At this time, the first battery cell 24 and the second battery cell 25 are discharged in series. When the switch element 21 is closed, it is in a conducting state, providing a low-impedance path for the discharge current. Because the switch element 21 is closed, the potential of the positive terminals of the first unidirectional conducting element 22 and the second unidirectional conducting element 23 is pulled low by the switch element 21. The negative terminal of the first unidirectional conducting element 22 is connected to the positive terminal of the first battery cell 24, and the negative terminal of the second unidirectional conducting element 23 is connected to the positive terminal of the second battery cell 25. Therefore, the negative terminal potentials of the first unidirectional conducting element 22 and the second unidirectional conducting element 23 are high, causing the first unidirectional conducting element 22 and the second unidirectional conducting element 23 to be cut off and not participate in conduction. The first battery cell 24 and the second battery cell 25 discharge simultaneously. The discharge current of the first battery cell 24 passes through the switching element 21, then through the second battery cell 25, and is output from the positive discharge terminal of the battery module 2 along with the discharge current of the second battery cell 25. This discharge current then passes through the load and is finally output to the negative discharge terminal of the battery module 2. When the battery module 2 is in a state where the battery cells are increasing their discharge current, the switching unit 3 is closed, and the first battery cell 24 and the second battery cell 25 are connected in series. The discharge current of the first battery cell 24 equals the discharge current of the second battery cell 25, which equals the load current.

[0059] Please refer to Figure 8 , Figure 8This diagram illustrates the battery module in a dynamic equalization discharge state. When battery module 2 is in this state, the main control chip 1 controls the switching element 21 to disconnect. At this time, the first battery cell 24 and the second battery cell 25 are connected in parallel through the first unidirectional conducting element 22 and the second unidirectional conducting element 23. Because the switching element 21 is disconnected, the discharge current cannot flow through it. Therefore, the discharge current path is divided into two paths. One path is that the second battery cell 25 outputs discharge current from its positive terminal, then passes through the load and is input from its negative terminal. When the first conducting element meets the conduction condition, the discharge current passes through the first unidirectional conducting element 22 and then returns to the negative terminal of the second battery cell 25. The other path is that the first battery cell 24 outputs discharge current from its positive terminal. When the second unidirectional conducting element 23 meets the conduction condition, the discharge current passes through the second unidirectional conducting element 23, then outputs from its positive terminal, passes through the load, returns to the negative terminal, and then flows from the negative terminal into the negative terminal of the first battery cell 24.

[0060] When battery module 2 discharges, if the voltage of the first battery cell 24 is higher than the voltage of the second battery cell 25, the potential of the positive terminal of the first battery cell 24 (i.e., the positive terminal of the second unidirectional conducting element 23) is higher than the potential of the positive terminal of the second battery cell 25 (i.e., the negative terminal of the second unidirectional conducting element 23). At this time, the forward conduction condition of the second unidirectional conducting element 23 is met, and the second unidirectional conducting element 23 conducts, forming a closed circuit in the discharge path of the first battery cell 24, causing the first battery cell 24 to discharge. Simultaneously, because the positive terminal potential of the first unidirectional conducting element 22 is lower than its negative terminal potential, the first unidirectional conducting element 22 is reverse-biased and cannot close the discharge circuit of the second battery cell 25. At this time, battery module 2 is discharged by the first battery cell 24 with the higher voltage, and the discharge current of the first battery cell 24 is half of the load current.

[0061] When the voltage of the first battery cell 24 is less than the voltage of the second battery cell 25, the potential of the positive terminal of the second battery cell 25 (i.e., the negative terminal of the second unidirectional conducting element 23) is higher than the potential of the positive terminal of the first battery cell 24 (i.e., the positive terminal of the second unidirectional conducting element 23). Therefore, the condition for the second unidirectional conducting element 23 to conduct is not met, and the second unidirectional conducting element 23 is turned off. Simultaneously, the potential of the positive terminal of the first unidirectional conducting element 22 is higher than the potential of its negative terminal, causing the first unidirectional conducting element 22 to conduct. At this time, the discharge circuit of the second battery cell 25 is closed, and the second battery cell 25 discharges. Furthermore, the discharge current of the second battery cell 25 is half of the load current.

[0062] When the voltages of the first battery cell 24 and the second battery cell 25 are equal, both the first unidirectional conducting element 22 and the second unidirectional conducting element 23 are turned on, and the first battery cell 24 and the second battery cell 25 discharge simultaneously. The sum of the discharge currents of the first battery cell 24 and the second battery cell 25 is equal to the load current.

[0063] Thus, by utilizing the forward conduction and reverse cutoff characteristics of the first unidirectional conducting element 22 and the second unidirectional conducting element 23, a parallel circuit is formed inside the battery module 2, thereby achieving current shunting and automatic balancing of the first battery cell 24 and the second battery cell 25. This automatic balancing mechanism requires no additional control circuits or complex algorithm logic, relying entirely on the physical characteristics of the unidirectional conducting elements. In practical applications, when a voltage difference occurs between the two battery cells, the system can quickly respond and adjust the discharge state, ensuring that the cell with the higher voltage preferentially bears part of the load current. As the discharge process continues, the cell with the lower voltage gradually participates in the discharge until the voltages of both cells tend to be consistent and they jointly supply power. This design not only simplifies the structure of the battery balancing system and reduces cost and energy consumption, but also improves the stability and reliability of the battery module 2, effectively avoiding over-discharge problems caused by uneven battery cell voltages and extending the overall service life of the battery module 2.

[0064] Example 2

[0065] This example provides a battery pack voltage equalization control method, which includes a charging equalization control process and / or a discharging equalization control process.

[0066] The charging equalization control process includes: detecting the voltage of each battery module 2 and identifying the battery module 2 with the highest voltage; controlling the battery module 2 with the highest voltage to bypass and controlling the remaining battery modules 2 to continue dynamic equalization charging. The discharging equalization control process includes: detecting the voltage of each battery module 2 in the discharging state and identifying the battery module 2 with the highest voltage; then controlling the battery cells of the battery module 2 with the highest voltage to increase the discharge current and controlling the battery cells of the remaining battery modules 2 to perform dynamic equalization discharging with normal discharge current.

[0067] Furthermore, during the charging equalization control process, at the beginning of charging, the voltage of all battery modules 2 in the battery pack is detected to identify the battery module 2 with the highest voltage. Then, at preset first intervals, the voltage of the battery module 2 in the bypass state and all other battery modules 2 that are continuing to charge are detected. After each round of detection is completed, the battery module 2 with the highest voltage in this round of detection is identified.

[0068] During the discharge equalization control process, at every preset second interval, the battery module 2 with the highest voltage among all discharged battery modules 2 is detected. After each round of detection is completed, the battery module 2 with the highest voltage in this round of detection is known.

[0069] It should be noted that the first preset interval and the second preset interval can be set to be the same or different. In this example, both the first preset interval and the second preset interval are set to 50ms.

[0070] Specifically, when the main control chip 1 receives a charging signal, the main control chip 1 controls multiple switching units 3 to close and multiple unidirectional conduction units 4 to open; after the multiple unidirectional conduction units 4 are opened, the main control chip 1 detects the voltage of multiple battery modules 2 and finds the battery module 2 with the highest voltage, so that the battery module 2 with the highest voltage is bypassed, and the remaining battery modules 2 are dynamically balanced for charging.

[0071] When the main control chip 1 receives a discharge signal, it controls multiple switching units 3 to open and multiple unidirectional conduction units 4 to close. After the multiple unidirectional conduction units 4 are closed, the main control chip 1 detects the voltage of multiple battery modules 2, identifies the battery module 2 with the highest voltage, and increases the discharge current of the battery cells in the battery module 2 with the highest voltage. The battery cells in the other battery modules 2 are dynamically balanced and discharged with normal discharge current.

[0072] During the charging phase, when the battery module 2 with the highest voltage is bypassed, the remaining battery modules 2 are dynamically and evenly charged to prevent overcharging or undercharging of some modules, ensuring that all battery modules 2 gradually reach voltage balance during charging. During the discharging phase, when the battery cells in the battery module 2 with the highest voltage increase their discharge current, the module 2 with the highest voltage will preferentially release energy, increasing the discharge rate. As discharge progresses, its voltage gradually decreases. At this time, the main control chip 1 continuously monitors the voltage changes of each module and adjusts the discharge strategy in real time, causing the remaining battery modules 2 to gradually increase their discharge capacity. Ultimately, this achieves a coordinated voltage decrease in all battery modules 2 during the discharge process, effectively improving the overall discharge efficiency and energy utilization of the battery pack, while preventing negative impacts on the performance of the entire battery pack due to abnormal voltage in individual battery modules 2.

[0073] The specific switching method of battery module 2 during charging and discharging is the same as in Embodiment 1. Please refer to Embodiment 1 for details, which will not be repeated here.

[0074] Furthermore, dynamic equalization charging includes: during the charging process, when the voltages of the individual battery cells in battery module 2 are not equal, the cell with the lower voltage in battery module 2 is charged, while the cell with the higher voltage is suspended from charging; when the voltages of the two individual battery cells are equal, the two individual battery cells are charged simultaneously.

[0075] Dynamic equalization discharge includes the following: During the discharge process, when the voltages of the individual battery cells in battery module 2 are not equal, the battery cell with the higher voltage discharges, while the battery cell with the lower voltage pauses discharging, and the discharge current of the battery cell with the higher voltage is equal to half of the load current. When the voltages of two battery cells in battery module 2 are equal, both battery cells discharge simultaneously, and the discharge current of each battery cell is equal to half of the load current.

[0076] Example 3

[0077] This embodiment provides a battery pack including the aforementioned battery pack voltage equalization control system.

[0078] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A battery pack voltage equalization control method, characterized in that, This includes a charge equalization control process and / or a discharge equalization control process; among which, The charging equalization control process includes: Detect the voltage of each battery module to identify the battery module with the highest voltage; Bypass the battery module with the highest voltage and control the remaining battery modules to continue dynamic equalization charging. The discharge equalization control process includes: The voltage of each battery module in a discharged state is detected to identify the battery module with the highest voltage. The system controls the battery module with the highest voltage to increase the discharge current of its individual cells for discharge, and controls the individual cells of the remaining battery modules to perform dynamic equalization discharge at normal discharge current. During the charging equalization control process, detecting the voltage of each battery module in the charging state includes: at the beginning of charging, first detecting the voltage of all battery modules in the battery pack to identify the battery module with the highest voltage; then, every preset first interval, detecting the voltage of the battery modules in the bypass state and all other battery modules that continue to charge; after each round of detection is completed, identifying the battery module with the highest voltage in this round of detection. The dynamic equalization charging includes: during charging, controlling the lower-voltage battery cells in the battery module to charge, while pausing the charging of the higher-voltage battery cells in the battery module; when the voltages of two battery cells are equal, the two battery cells charge simultaneously; during discharging, controlling the higher-voltage battery cells in the battery module to discharge, while pausing the discharging of the lower-voltage battery cells in the battery module; the discharge current of the higher-voltage battery cells is equal to half of the load current; when the voltages of two battery cells are equal, the two battery cells discharge simultaneously, and the discharge current of each battery cell is equal to half of the load current.

2. The control method according to claim 1, characterized in that, During the discharge equalization control process, detecting the voltage of each battery module in the discharge state includes: every preset second interval, detecting the battery module with the highest voltage among all discharged battery modules, and after each round of detection is completed, knowing the battery module with the highest voltage in this round of detection.

3. A battery pack voltage balancing control system, characterized in that, The battery pack voltage equalization control method according to any one of claims 1-2 includes: a main control chip, multiple battery modules, multiple switching units, and multiple unidirectional conduction units; each battery module has a charging positive terminal, a charging negative terminal, a discharging negative terminal, and a discharging positive terminal; the main control chip is electrically connected to the multiple battery modules and the multiple switching units, a switching unit is connected between the charging negative terminal and the charging positive terminal of two adjacent battery modules, and a unidirectional conduction unit is connected between the discharging positive terminal and the discharging negative terminal of two adjacent battery modules; wherein, when the main control chip receives a charging signal, the main control chip controls the multiple switching units to close, and the multiple unidirectional conduction units are activated. When a battery module is disconnected, the main control chip detects the voltage of each battery module to identify the module with the highest voltage. It then controls the battery module with the highest voltage to bypass and controls the other battery modules to dynamically balance charging. When the main control chip receives a discharge signal, it controls multiple switching units to disconnect and multiple unidirectional conducting units to close. The main control chip then detects the voltage of each battery module in the discharge state to identify the module with the highest voltage. It then controls the battery module with the highest voltage to increase the discharge current of its individual cells and controls the individual cells of the other battery modules to dynamically balance discharge with normal discharge current.

4. The control system according to claim 3, characterized in that, When the main control chip receives a charging signal, at the beginning of charging, the main control chip first detects the voltage of all battery modules to determine the battery module with the highest voltage. Then, at a preset first interval, the main control chip detects the voltage of the battery modules in bypass mode and all other battery modules that are continuing to charge. After each round of detection is completed, the battery module with the highest voltage in this round of detection is determined.

5. The control system according to claim 3, characterized in that, When the main control chip receives a discharge signal, it detects the battery module with the highest voltage among all the discharging battery modules at a preset second interval. After each round of detection is completed, it knows the battery module with the highest voltage in this round of detection.

6. The control system according to claim 3, characterized in that, Each battery module includes a switching element, a first unidirectional conducting element, a second unidirectional conducting element, a first battery cell, and a second battery cell. One end of the switching element is connected to the charging positive terminal, the positive terminal of the first battery cell, and the positive terminal of the second unidirectional conducting element, respectively, and the other end is connected to the charging negative terminal, the negative terminal of the second battery cell, and the negative terminal of the first unidirectional conducting element. The switching element is also connected to a main control chip. The negative terminal of the first battery cell is connected to the positive terminal and the discharging negative terminal of the first unidirectional conducting element, respectively. The positive terminal of the second battery cell is connected to the negative terminal and the discharging positive terminal of the second unidirectional conducting element, respectively. When the main control chip receives a charging signal, after identifying the battery module with the highest voltage, the main control chip controls the switch in the battery module with the highest voltage. When the main control chip closes the switch element, it bypasses the battery module with the highest voltage. The main control chip also controls the switching elements in the remaining battery modules to open, and the first and second battery cells are connected in parallel to charge the remaining battery modules. When the main control chip receives a discharge signal, it determines which battery module has the highest voltage and controls the switch element in that module to close. The first and second battery cells are connected in series, causing the first and second battery cells in the highest voltage battery module to increase their discharge current and discharge. The main control chip also controls the switching elements in the remaining battery modules to open, and the first and second battery cells are connected in parallel, allowing the first and second battery cells in the remaining battery modules to discharge with normal current.

7. A battery pack, characterized in that, Includes the battery pack voltage equalization control system as described in any one of claims 3-6.

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