Lithium battery BMS equalization method and equipment

Abstract

The invention relates to the technical field of BMS, and discloses a lithium battery BMS equalization method and equipment, and the method comprises the steps: obtaining a first charge state of each cell and a periodic charge amount in a first time period of a semi-online period; in a second time period of the semi-online period, determining a to-be-balanced battery cell according to the first charge state and calculating a balancing duty ratio parameter; in a third time period of the semi-online period, the equalization circuit of each to-be-equalized battery cell is driven according to the equalization duty ratio parameter to carry out discharge equalization, and the actual equalization charge quantity is counted; and updating the first charge state based on the actual balanced charge quantity to obtain a second charge state, calculating a second capacity parameter according to the periodically charged charge quantity, and starting a first time period of the next half on-line period based on the second charge state and the second capacity parameter, thereby realizing continuous tracking of the state of the battery cell and dynamic correction of the parameters. And compared with off-line equalization, the response frequency of the dynamic change of the battery cell state in the charging process is improved.

Description

Technical Field

[0001] This invention relates to the field of BMS technology, and in particular to a lithium battery BMS equalization method and equipment. Background Technology

[0002] During the charging and discharging process of lithium battery packs, inconsistencies in capacity, internal resistance, and state of charge exist among individual cells due to differences in manufacturing processes, usage environments, and uneven aging. This leads to a decline in overall battery pack performance, a shortened cycle life, and even safety hazards. To address the issue of cell inconsistency, an equalization circuit continuously operates throughout the charging process. However, existing technologies tend to cause the equalization resistor to overheat for extended periods, resulting in significant energy loss and increased power consumption, which in turn affects the accuracy of state estimation and the real-time performance of equalization control. Summary of the Invention

[0003] This invention provides a lithium battery BMS balancing method and device, thereby realizing continuous tracking of cell status and dynamic correction of parameters, which improves the response frequency to dynamic changes in cell status during charging compared with offline balancing.

[0004] The first aspect of this invention provides a lithium battery BMS balancing method, the lithium battery BMS balancing method comprising: During the first period of the semi-online cycle, the first state of charge and the amount of charge charged in the cycle for each cell are obtained. During the second period of the half-online cycle, the cells to be balanced are determined based on the first state of charge and the balancing duty cycle parameters are calculated. During the third period of the half-online cycle, the equalization circuit of each cell to be equalized is driven to perform discharge equalization according to the equalization duty cycle parameter and the actual equalization charge is counted. The first state of charge is updated based on the actual balanced charge amount to obtain the second state of charge, and the second capacity parameter is calculated according to the periodic charge amount. The first period of the next half of the online cycle is started based on the second state of charge and the second capacity parameter.

[0005] In conjunction with the first aspect, in a first implementation of the first aspect of the present invention, it further includes: Read the historical capacity parameters and historical state of charge of each cell, and configure the fixed sampling period and equalization start threshold of the BMS system; Set the total duration of the semi-online cycle in the BMS system; The total duration of the semi-online cycle is divided into a first time period for collecting charging data, a second time period for calculating equalization parameters, and a third time period for performing equalization control according to a preset time ratio. The duration of the third time period is greater than the sum of the durations of the first and second time periods.

[0006] In conjunction with the first aspect, in a second implementation of the first aspect of the present invention, during the first time period of the semi-online cycle, acquiring the first state of charge and the amount of charge charged in the cycle for each cell includes: During the first period of the semi-online cycle, the terminal voltage and charging current of each cell are collected according to a fixed sampling period; The state of charge increment is calculated based on the charging current and the charging coulombic efficiency. The state of charge increment is accumulated with the first capacity parameter of each cell and the state of charge at the previous sampling point to obtain the real-time state of charge, and the real-time state of charge of each cell is taken as the first state of charge at the end of the first time period. The amount of charge charged during the cycle is calculated based on the charging current and the fixed sampling period.

[0007] In conjunction with the first aspect, in a third implementation of the first aspect of the present invention, during the second time period of the half-online cycle, determining the cell to be balanced based on the first state of charge and calculating the balancing duty cycle parameter includes: In the second time period of the semi-online cycle, the average state of charge and the state of charge deviation are calculated based on the first state of charge. The state of charge deviation is compared with a preset deviation threshold to determine whether to initiate the equalization control process. When the equalization control process is started, the cells are traversed and the cells with the first state of charge higher than the average state of charge are selected as cells to be equalized. The difference between the first state of charge and the average state of charge of each cell to be equalized is multiplied by the first capacity parameter of the corresponding cell to obtain the target amount of released charge. The required balancing time for each cell to be balanced is calculated based on the target charge release amount. The required balancing time for each cell to be balanced is compared with the available time of the third time period to obtain the balancing duty cycle parameter of each cell to be balanced.

[0008] In conjunction with the first aspect, in a fourth implementation of the first aspect of the present invention, comparing the state of charge deviation with a preset deviation threshold to determine whether to initiate an equalization control process includes: The state of charge deviation with the largest value is taken as the maximum deviation value, and the state of charge deviation with the smallest value is taken as the minimum deviation value. Calculate the target deviation value based on the maximum deviation value and the minimum deviation value; The target deviation value is compared with a preset threshold. When the target deviation value is greater than the preset threshold, the equalization control process is initiated; when the target deviation value is less than or equal to the preset threshold, the equalization control process is skipped and the next half of the online cycle is started directly.

[0009] In conjunction with the first aspect, in the fifth implementation of the first aspect of the present invention, the required balancing time for each cell to be balanced is calculated based on the target released charge amount, and the required balancing time for each cell to be balanced is compared with the available time of the third time period to obtain the balancing duty cycle parameter of each cell to be balanced, including: Obtain the cell voltage of each cell to be balanced at the end of the first time period, and divide the cell voltage by the balancing resistor to obtain the balancing current of each cell to be balanced. Divide the target released charge by the product of the corresponding equalization current and the equalization efficiency coefficient to obtain the required equalization time; The required balancing durations are summed to obtain an accumulated value, and the accumulated value is compared with the available duration of the third time period; When the accumulated value is less than or equal to the available duration, the equalization duty cycle parameter of each cell to be equalized is set to full duty cycle. When the accumulated value is greater than the available duration, the equalization duty cycle parameter is calculated based on the ratio of the required equalization duration to the single-path allocation duration.

[0010] In conjunction with the first aspect, in the sixth implementation of the first aspect of the present invention, during the third time period of the half-online cycle, the equalization circuits of each cell to be equalized are driven to perform discharge equalization according to the equalization duty cycle parameter, and the actual equalization charge is counted, including: The PWM control signal is generated based on the equalization duty cycle parameter to drive the MOSFET switch of each cell to be equalized. By controlling the MOSFET to turn on and off, the equalization resistor is connected to both ends of the cell to form a discharge circuit. During the third period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced exceeds the temperature safety threshold, the PWM control signal of the cell to be balanced is turned off and the discharge circuit is cut off. At the end of the third time period, the effective balancing time of each cell to be balanced is obtained and the temperature protection pause time is deducted. The effective balancing time is then multiplied by the corresponding balancing current, balancing duty cycle parameter and balancing efficiency coefficient to obtain the actual balancing charge.

[0011] In conjunction with the first aspect, in the seventh implementation of the first aspect of the present invention, during the third time period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with a temperature safety threshold. When the surface temperature of any cell to be balanced exceeds the temperature safety threshold, the PWM control signal of the cell to be balanced is turned off and the discharge circuit is cut off, including: During the third time period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced is greater than or equal to the temperature safety threshold, the PWM control signal corresponding to the cell to be balanced is turned off and the balancing circuit of the cell is cut off. The temperature protection flag of the cell to be balanced is set in the status register and the cell to be balanced is added to the temperature monitoring list. When the surface temperature of the corresponding cell to be balanced in the temperature monitoring list drops below the temperature recovery threshold, the temperature protection flag of the corresponding cell to be balanced is cleared, the remaining amount of charge to be released and the remaining balancing time of the corresponding cell to be balanced are calculated, and it is determined whether to restart the discharge circuit of the corresponding cell to be balanced.

[0012] In conjunction with the first aspect, in the eighth implementation of the first aspect of the present invention, the first state of charge is updated based on the actual balanced charge amount to obtain a second state of charge, and a second capacity parameter is calculated based on the periodic charge amount. The first time period of the next half of the online cycle is then initiated based on the second state of charge and the second capacity parameter, including: Divide the actual balanced charge by the corresponding first capacity parameter to obtain the state of charge drop, and subtract the corresponding state of charge drop from the first state of charge to obtain the second state of charge. Divide the amount of charge charged in the cycle by the increment of the state of charge in the current half-online cycle to obtain the equivalent capacity value. Take a weighted average of the equivalent capacity value and the first capacity parameter to obtain the second capacity parameter. The second state of charge and the second capacity parameter are used as the initial state of charge and initial capacity parameter for the next half of the online cycle, and the first time period of the next half of the online cycle is started to re-acquire charging data.

[0013] A second aspect of the present invention provides a lithium battery BMS balancing device, the lithium battery BMS balancing device comprising: The acquisition module is used to acquire the first state of charge and the amount of charge charged in the cycle for each cell during the first period of the semi-online cycle. The calculation module is used to determine the cells to be balanced and calculate the balancing duty cycle parameters based on the first state of charge during the second time period of the half-online cycle. The discharge equalization module is used to drive the equalization circuit of each cell to be equalized to perform discharge equalization and count the actual equalization charge amount in the third period of the half-online cycle according to the equalization duty cycle parameter. The startup module is used to update the first state of charge based on the actual balanced charge amount to obtain the second state of charge, calculate the second capacity parameter according to the periodic charge amount, and start the first period of the next half of the online cycle based on the second state of charge and the second capacity parameter.

[0014] Compared to existing technologies, this invention divides the charging process into multiple fixed-duration semi-online cycles. Each cycle is sequentially divided into a data acquisition period, a parameter calculation period, and an equalization execution period, achieving temporal decoupling between charging state estimation and equalization control. During the data acquisition period, the focus is on voltage and current acquisition and state of charge calculation, ensuring the accuracy of the charging state estimation. During the parameter calculation period, equalization demand judgment and duty cycle allocation are centrally processed, avoiding computational resource conflicts. During the equalization execution period, the equalization circuit operates centrally, significantly reducing the operating time of the equalization circuit and the overall system power consumption compared to full-cycle online equalization. By setting the duration of the third period to be greater than the sum of the first two periods, sufficient time window is ensured for equalization control to complete charge release. Simultaneously, this invention employs a periodic data inheritance mechanism, using the second state of charge and second capacity parameters calculated in the current cycle as the initial parameters for the next cycle, achieving continuous tracking of the cell state and dynamic parameter correction, thus improving the response frequency to dynamic changes in the cell state during charging compared to offline equalization. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0017] Figure 1 This is a schematic flowchart of the lithium battery BMS balancing method provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the working process of the semi-online cyclic equalization control method for lithium battery BMS provided in this embodiment of the invention. Figure 3 This is a working state diagram of the full-cycle online balancing method provided in the embodiments of the present invention; Figure 4 This is a diagram showing the working state of the offline load balancing method provided in this embodiment of the invention. Figure 5 This is a diagram showing the working state of the semi-online periodic cyclic equilibrium method provided in this embodiment of the invention. Figure 6 This is a schematic block diagram of the structure of the lithium battery BMS balancing device provided in the embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0020] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items, and all possible combinations, and includes such combinations. See also Figure 1 One embodiment of the lithium battery BMS equalization method in this invention includes: Step 100: During the first time period of the semi-online cycle, obtain the first state of charge and the amount of charge charged in the cycle for each cell; In this embodiment, during the first time period of the semi-online cycle, continuous measurement is performed using a fixed sampling interval Δt. The main control chip initiates the AFE chip through the control interface to sequentially collect the terminal voltage V(k) of all cells. Simultaneously, the main circuit current I(k) is measured using a Hall sensor, and zero-point correction is performed on I(k) to remove offset errors. The main control chip, combined with the preset charging coulombic efficiency η, calculates the increment of state of charge per unit time ΔS = η × I(k) × Δt ÷ Q based on the current I(k), where Q is the first capacity parameter of the corresponding cell, and ΔS reflects the increase in state of charge per unit capacity under the current current condition. The ΔS value is added to the state of charge S(k) of the previous sampling point to form the updated S(k+1), and the integration process is continuously performed to cover the entire first time period. When the time reaches the end of the first time period, for example, t = 120 seconds, the main control chip records the S(k+1) value of each cell at this time as the first state of charge S1 of this cycle. Meanwhile, the main control chip calculates the single-point charging charge ΔQ=I(k)×Δt by multiplying the current value I(k) of each sampling point by Δt, and continues to sum up to form the total charging charge Q1 of the cycle.

[0022] Step 200: In the second time period of the half-online cycle, determine the cells to be balanced based on the first state of charge and calculate the balancing duty cycle parameters; In this embodiment, during the second time period of the semi-online cycle, the first state of charge S1 of each cell, which was collected and integrated in the previous time period, is read, and the average value S of all cells is calculated by the main control chip. a S a =ΣS1÷n, where n is the number of cells connected in series. Calculate the state-of-charge deviation ΔS=S1 for each cell. S a And determine the maximum deviation ΔS m Does it exceed the preset deviation threshold θ, for example, θ=2%? If ΔS m If ΔS ≤ θ, then the consistency between cells is considered good and equalization control is not triggered; however, when ΔS m If S1 > θ, then the balancing control process begins. After starting the balancing process, all cells are traversed again, and all cells with S1 > S1 are processed. a The selected cells are added to the balancing set H, and for each cell in H, its S1 and S2 are compared. a The difference ΔS is multiplied by the first capacity parameter Q of the battery cell to obtain the target released charge Q0, i.e., Q0 = ΔS × Q. This value represents the amount of charge the battery cell needs to release in order to achieve S. a The total charge to be released. Combining the cell voltage V at the end of the first time period and the preset balancing resistor R, the balancing current I is calculated using I = V ÷ R. Then, the required balancing time T0 is calculated by substituting Q0 ÷ (I × η), where η is the balancing efficiency constant, for example, η = 0.92. The main control chip calculates all T0s and sums them, denoted as T.t , and the fixed upper limit T of the third time period m =420 seconds for comparison, if T t ≤T m Therefore, a duty cycle D=1.0 is set for each cell, meaning it will continue to conduct until T0 is completed, and when T... t >T m When that happens, normalize the allocation of all T0s, and assign T... m The cells are divided equally according to their priority after being sorted by ΔS, and the value of D for each cell is calculated as D = T0 ÷ T. ma T ma The maximum allocatable duration of the battery cell, if T0 > T ma If so, D = 1.0; otherwise, D is set proportionally.

[0023] Step 300: In the third period of the half-online cycle, drive the equalization circuit of each cell to be equalized to perform discharge equalization according to the equalization duty cycle parameter and count the actual equalization charge. In this embodiment, the main control chip reads the duty cycle parameter D calculated during the second time period and configures an independent PWM timer for each cell to be balanced. Based on the value of D, it calculates the set value of its comparison register, sets the PWM control period to 1ms, and the duty cycle resolution to 0.1%, forming a periodic PWM waveform. The main control chip drives the corresponding MOSFET through the PWM output control signal, causing it to close and conduct within the conduction time determined by D in each PWM cycle. This connects the preset balancing resistor R across the two ends of the cell to form a closed discharge circuit. During the low-level phase of the PWM, the MOSFET is turned off, and the balancing circuit is disconnected. During the third time period of the half-online cycle, the surface temperature T of all cells to be balanced is continuously sampled at a period of Δt = 100ms, and T is compared with the preset upper temperature limit T in real time. s When comparing, if T ≥ T of a certain cell s For example, T s If the temperature reaches 45℃, it is determined to be an excessive temperature rise. The main control chip immediately interrupts the PWM output corresponding to that cell and cuts off its discharge path. At the same time, it sets the temperature protection flag and records the start time of the protection. If subsequent monitoring shows that the cell temperature T drops to the temperature recovery threshold T... r The following, for example, T r If the temperature reaches 40℃, the battery cell is determined to have returned to a safe state. The system clears the protection flag and restarts its PWM output, accumulating the interruption time as the temperature protection pause time. When the end time of the third period, t=600 seconds, is reached, the main control chip forcibly shuts down all PWM outputs and turns off all MOSFETs, stopping the equalization discharge operation. Subsequently, the main control chip reads the cumulative conduction time T of each battery cell to be equalized. eThe effective balancing time is obtained by subtracting the pause duration from the PWM on-counter, and then multiplied by the balancing current I, circuit duty cycle D, and balancing efficiency η of the cell to calculate Q. a =I×D×T e ×η gives the actual balanced charge Q released by the cell in this cycle. a .

[0024] Figure 2 This diagram illustrates the working process of a semi-online cyclic equalization control method for lithium-ion batteries using a BMS. The horizontal axis represents the time progression of a single semi-online cycle, divided into three phases: the first phase (data acquisition, 20%), the second phase (parameter calculation, 10%), and the third phase (equalization execution, 70%). The vertical axis represents the State of Charge (SOC) of each cell. Solid, dashed, and dotted lines represent three cells with different initial SOCs. In the first phase, the SOC of each cell increases with charging. In the second phase, the system calculates the first SOC1 and the maximum SOC deviation ΔSOC_max. In the third phase, the high-charge-state cells (solid lines) discharge through the equalization circuit, causing their SOC to decrease, while the low-charge-state cells (dotted lines) continue charging, increasing their SOC. Finally, at the end of the cycle, all cells reach the second SOC2, significantly reducing the inter-cell deviation and achieving cyclic equalization control.

[0025] Step 400: Update the first state of charge based on the actual balanced charge amount to obtain the second state of charge, calculate the second capacity parameter according to the periodic charge amount, and start the first period of the next half of the online cycle based on the second state of charge and the second capacity parameter.

[0026] In this embodiment, after the third time period ends, the state update logic is entered, and the main control chip retrieves the actual equalized charge Q released by all the cells that have completed equalization in the current cycle. a And in conjunction with its first capacity parameter Q, the decrease in state of charge ΔS=Q is calculated. a ÷Q, and then subtract ΔS from the first state of charge S1 at the end of this cycle to obtain the second state of charge S2 = S1 after balance correction. ΔS; For cells not participating in equalization, their S2 is directly inherited from S1 and does not need to be deducted. Based on the total charging charge Q1 accumulated in this cycle, and the increment ΔS'=S2 between S2 and the initial state of charge S0 of the previous cycle. S0 calculates the equivalent capacity value Q' = Q1 ÷ ΔS' for this cycle. The equivalent capacity value represents the effective energy storage capacity exhibited by the cell under actual charging behavior. Then, Q' is weighted and averaged with the current first capacity parameter Q, for example, by combining them in the manner of Q2 = 0.9 × Q + 0.1 × Q', to generate the second capacity parameter Q2 to adapt to the capacity evolution trend. The updated S2 and Q2 are written into the status register as the initial state of charge and capacity input for the next cycle, and the time stamp t is reset to zero. The first period of the next half of the online cycle is started, and voltage and current acquisition and integration calculation are restarted, entering a new SOC calculation and equalization judgment loop.

[0027] Figure 3 This is a diagram illustrating the working state of the full-cycle online balancing method. Throughout the charging process, the charging state and balancing state occur synchronously, with the balancing circuit operating continuously from the start of charging (t=0) to the end of charging (t=T). The advantage of this method is that the balancing circuit operates continuously, enabling real-time response to changes in cell state. However, the system has high power consumption, and the balancing resistors generate significant heat over time, leading to substantial energy loss. Furthermore, the simultaneous estimation of charging state and balancing control increases the computational burden.

[0028] Figure 4 This is a diagram illustrating the working state of the offline balancing method. During the charging phase (t=0 to t=T), the system only charges without performing balancing control, and the state of charge deviation of the cells gradually accumulates during charging. After charging is completed, the charger is disconnected, and the offline balancing phase begins, where the cells are balanced in a concentrated manner. This method is characterized by the separation of charging and balancing, resulting in low system power consumption. However, it cannot respond to dynamic changes in the cell state during charging, leading to a delayed balancing effect and making it difficult to meet the needs of fast charging scenarios.

[0029] Figure 5 This diagram illustrates the working state of the semi-online cyclic equalization method. The entire charging process is divided into multiple fixed-duration semi-online cycles. Each cycle sequentially includes a data acquisition period (20%), a parameter calculation period (10%), and an equalization execution period (70%). The charging process (light gray grid area) spans the entire cycle. During the data acquisition period, voltage and current are collected and the state of charge (SOC) is calculated. During the parameter calculation period, equalization requirements are determined and duty cycle parameters are calculated. During the equalization execution period, the equalization circuit is activated to discharge cells in the high-charge state. At the end of the cycle, the second SOC2 and the updated capacity parameters are passed to the next cycle as initial parameters, achieving continuous state tracking. This invention achieves a balance between power consumption, real-time performance, and dynamic response capability.

[0030] In one specific embodiment, it further includes: Read the historical capacity parameters and historical state of charge of each cell, and configure the fixed sampling period and equalization start threshold of the BMS system; Set the total duration of the semi-online cycle in the BMS system; The total duration of the semi-online cycle is divided into three periods according to a preset time ratio: a first period for collecting charging data, a second period for calculating equalization parameters, and a third period for executing equalization control. The duration of the third period is greater than the sum of the durations of the first and second periods.

[0031] In this embodiment, the main control chip accesses the non-volatile memory to read the previously recorded capacity parameter Q and state of charge S of each cell, and loads these historical values ​​into the current working register for initialization. The main control chip sets a fixed sampling interval Δt for this operation, for example, Δt=100ms, and writes it to the system control module to synchronize all sampling operations. Simultaneously, it loads a preset equalization start threshold θ, for example, θ=2%, as a reference standard for determining whether cell differences require equalization operations. The total running time T of the semi-online cycle is set to a fixed value, for example, T=600 seconds, and the total time is divided into three stages according to a preset ratio. The first stage is used to collect voltage and current data, the second stage is used to analyze the cell state and calculate equalization parameters, and the third stage is used to drive the equalization circuit for energy regulation. For example, the first stage accounts for 0.2%, for example, T1=120 seconds; the second stage accounts for 0.1%, for example, T2=60 seconds; and the third stage accounts for 0.7%, for example, T3=420 seconds, thus satisfying the requirement that the duration of the third stage is greater than the sum of the first and second stages.

[0032] In one specific embodiment, the process of performing step 100 may specifically include the following steps: During the first period of the semi-online cycle, the terminal voltage and charging current of each cell are collected according to a fixed sampling period; The state-of-charge increment is calculated based on the charging current and the charging coulombic efficiency. The state of charge increment is accumulated with the first capacity parameter of each cell and the state of charge at the previous sampling point to obtain the real-time state of charge. At the end of the first time period, the real-time state of charge of each cell is taken as the first state of charge. The amount of charge charged per cycle is calculated based on the charging current and a fixed sampling period.

[0033] In this embodiment, a fixed sampling interval Δt is set during the initialization phase of the semi-online cycle, for example, Δt = 100ms. The main control chip is configured to start a timed sampling mechanism, driving the AFE chip to perform a complete channel polling once according to Δt. During each sampling cycle, the AFE chip sequentially connects to the terminal voltage channels of each cell and inputs the analog signal into the ADC module for numerical conversion. The main control chip reads the instantaneous voltage V(k) of each cell as the current sample, and simultaneously acquires the charging current I(k) at that moment through a Hall current sensor, performing offset correction on I(k) to eliminate zero-drift interference. Combined with a preset charging coulombic efficiency η, for example, η = 0.98, the state-of-charge increment is calculated for the current sampling point according to the formula ΔS = η × I(k) × Δt ÷ Q, where Q is the first capacity parameter preset in the EEPROM for the cell, and ΔS represents the relative charge ratio charged during the sampling cycle. The main control chip performs an update operation on the current state-of-charge S(k) of each cell, accumulating ΔS to the S(k) of the previous sampling point. 1), thus obtaining S(k) = S(k 1) + ΔS, and write the updated value to the real-time state buffer. This operation will continue until the end of the first time period, for example, t=120 seconds. At this moment, the main control chip performs a complete synchronous update of S(k) for all cells and stores it in the state register as the first state of charge S1 of this cycle. At the same time, in order to obtain the total charging charge Q1 of this cycle, the product calculation is performed by I(k) and Δt at each sampling point to obtain the instantaneous charging amount ΔQ=I(k)×Δt at the current sampling point. A charging integration register is established in the main control chip, and each ΔQ is continuously accumulated until the end of the first time period to obtain Q1=ΣΔQ.

[0034] In one specific embodiment, the process of performing step 200 may specifically include the following steps: In the second period of the semi-online cycle, the average state of charge and the state of charge deviation are calculated based on the first state of charge. The state of charge deviation is compared with a preset deviation threshold to determine whether to initiate the equalization control process. When the equalization control process is started, the cells are traversed and those with a first state of charge higher than the average state of charge are selected as cells to be equalized. The difference between the first state of charge and the average state of charge of each cell to be equalized is multiplied by the first capacity parameter of the corresponding cell to obtain the target amount of released charge. The required balancing time for each cell to be balanced is calculated based on the target charge release amount. The required balancing time for each cell to be balanced is compared with the available time in the third time period to obtain the balancing duty cycle parameter for each cell to be balanced.

[0035] In this embodiment, during the second time period of the half-online cycle, the main control chip reads the first state of charge S1 of each cell at the end of the first time period, and calculates the average value S using all S1 values. a =ΣS1÷n, where n is the number of battery cells, and the value of each cell relative to S is calculated individually. a The deviation ΔS=S1 S a Then, the maximum positive deviation and the maximum negative deviation are found among all cells to form the maximum deviation amplitude ΔS of the entire group of cells. m =max(S1) min(S1), ΔS m Compare with a preset threshold θ, for example, θ = 2%, if ΔS m If ΔS ≤ θ, the cells are considered to be in the same state, and no balancing process needs to be initiated; the system directly enters the next cycle. m If S1 > θ, then the balancing process begins. In this state, the main control chip iterates through all cells to ensure that S1 > S2. a The cells are added to the set H to be balanced, and each cell in set H is treated according to ΔQ=(S1) S a The target charge release amount ΔQ is calculated by multiplying Q by 1, where Q is the first capacity parameter. Then, the equalization current I = V ÷ R is calculated from the voltage V at the end of the first time period of the cell and the set equalization resistor R. The target charge amount is then divided by the product of the equalization current and the efficiency η, i.e., T = ΔQ ÷ (I × η), to obtain the theoretical equalization time T required for the cell. All T values ​​are summed to form T. t Total demand time and maximum available time T in the third period m =420 seconds for comparison, if T t ≤T m Then, set the duty cycle D=1.0 for all cells, that is, achieve full power balance in the third time period; if T t >T m Then T m Allocate in descending order of ΔS, with a maximum allocation T per cell. x =T m ÷m, where m is the number of cells in set H, according to D = min(T÷T) x ,1.0) Calculate the duty cycle parameter D.

[0036] In one specific embodiment, the process of comparing the state of charge deviation with a preset deviation threshold and determining whether to initiate the equalization control process may specifically include the following steps: The state of charge deviation with the largest value is taken as the maximum deviation value, and the state of charge deviation with the smallest value is taken as the minimum deviation value. Calculate the target deviation value based on the maximum and minimum deviation values; Compare the target deviation value with a preset threshold; When the target deviation value is greater than the preset threshold, the equalization control process is started. When the target deviation value is less than or equal to the preset threshold, the equalization control process is skipped and the next half of the online cycle is started directly.

[0037] In this embodiment, after the start of the second time period, the main control chip reads the state of charge S1 of each cell at the end of the first time period, and uses the average value S1 of all S1s as the basis for calculation. a For reference, the deviation ΔS=S1 of each cell is calculated individually. S a These deviations are stored in a deviation array, and the deviation value ΔS with the largest value is retrieved from the deviation array. + The smallest deviation value ΔS - And perform difference calculation ΔS t =ΔS + ΔS - ΔS t This is the target deviation value, representing the maximum SOC inconsistency range of the current cell group. ΔS t Compare numerically with a threshold θ, for example, if θ is set to 2%, when ΔS t When ΔS > θ, it indicates that the current cell state distribution has exceeded the allowable range, and it is determined that a balancing operation needs to be performed, thus entering the balancing parameter calculation and PWM control process; conversely, when ΔS > θ, it indicates that the current cell state distribution has exceeded the allowable range, and it is determined that a balancing operation needs to be performed, thus entering the balancing parameter calculation and PWM control process; t When ≤θ, it means that the cell state distribution is within the tolerance range. The main control chip will skip the equalization execution stage, directly update the internal counter and start the first period of the next half of the online cycle, thereby saving energy and reducing unnecessary MOSFET conduction times.

[0038] In one specific embodiment, the process of calculating the required balancing time for each cell to be balanced based on the target released charge amount, and comparing the required balancing time for each cell to be balanced with the available time of the third time period to obtain the balancing duty cycle parameter of each cell to be balanced can specifically include the following steps: Obtain the cell voltage of each cell to be balanced at the end of the first time period, divide the cell voltage by the balancing resistor, and obtain the balancing current of each cell to be balanced. Divide the target released charge by the product of the corresponding equalization current and the equalization efficiency coefficient to obtain the required equalization time; The required balancing durations are summed to obtain the cumulative value, and then the cumulative value is compared with the available duration of the third time period; When the accumulated value is less than or equal to the available time, the equalization duty cycle parameter of each cell to be equalized is set to full duty cycle. When the accumulated value is greater than the available time, the equalization duty cycle parameter is calculated based on the ratio of the required equalization time to the single-path allocation time.

[0039] In this embodiment, the voltage value V corresponding to the end of the first time period for each cell to be balanced is extracted from the state buffer. The V value is then divided by the balancing resistor R to obtain the balancing current I = V ÷ R. This current represents the theoretical discharge capacity of the balancing circuit in full conduction mode. The target released charge Q is divided by I × η for each cell to obtain the required balancing time T = Q ÷ (I × η), where η is the balancing efficiency coefficient, for example, η = 0.92. The main control chip sums all T values ​​to form the total required time T. s The accumulated value is then compared with the maximum allowed duration T of the third time period. m =420 seconds for comparison, when T s ≤T m When T indicates that the number of cells to be balanced and the target charge are both within the discharge capacity coverage range, a full duty cycle D=1.0 can be configured for all cells to ensure that the balancing circuit continues to conduct throughout the entire third time period until the charge release is completed; when T s >T m If all cells to be balanced operate at full duty cycle simultaneously, it will exceed the time budget. Therefore, time-sharing scheduling is implemented for the balancing process. At this time, the main control chip uses T... m Divide by the number of cells to be balanced, m, and calculate the single-path distribution time T. x =T m ÷m, and T for each cell with T x The ratio is calculated to obtain the equilibrium duty cycle D = min(T ÷ T). x ,1.0), ensuring that high-deviation cells obtain a higher conduction ratio, while low-deviation cells automatically compress the duty cycle, realizing a reasonable dynamic allocation of time resources.

[0040] In one specific embodiment, the process of performing step 300 may specifically include the following steps: The PWM control signal is generated based on the equalization duty cycle parameter to drive the MOSFET switch of each cell to be equalized. By controlling the MOSFET to turn on and off, the equalization resistor is connected to both ends of the cell to form a discharge circuit. During the third period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced exceeds the temperature safety threshold, the PWM control signal of the cell to be balanced is turned off and the discharge circuit is cut off. At the end of the third time period, the effective balancing time of each cell to be balanced is obtained and the temperature protection pause time is deducted. The effective balancing time is then multiplied by the corresponding balancing current, balancing duty cycle parameter and balancing efficiency coefficient to obtain the actual balancing charge.

[0041] In this embodiment, after entering the third time period, the main control chip reads the equalization duty cycle parameter D calculated in the second time period and configures an independent PWM control module for each cell to be equalized. The PWM period is set to a fixed value, such as 1ms, and the duty cycle resolution is set to 0.1%. The main control chip calculates the corresponding comparison register value based on D and loads it into the PWM register, so that the control signal outputs a high level according to the conduction time determined by D in each PWM cycle, thereby driving the MOSFET on the corresponding cell to conduct. During the MOSFET conduction period, a preset equalization resistor R is connected between the positive and negative terminals of the cell to form a closed discharge circuit, so that the cell continuously releases charge with an equalization current I. The main control chip simultaneously starts the temperature acquisition task, acquiring the cell surface temperature T from each NTC temperature channel at a fixed interval Δt=100ms, and comparing it with the temperature safety threshold T. s For example, T s =45℃, for comparison, when the temperature of a certain cell T≥T s Upon this event, the temperature protection logic is immediately triggered. The main control chip shuts down its PWM control output, forcibly turns off the MOSFET, and records the channel as an interrupt state affected by temperature control. Simultaneously, a timer begins for subsequent deduction. At this time, the system marks the cell's state as paused and continues to periodically sample its temperature. If the temperature subsequently drops to the recovery threshold T... r For example, T r If the temperature reaches 40℃, the temperature protection flag will be cleared and PWM output will be restored. Simultaneously, the cumulative time Δt during the protection period will be recorded. p When the third time period reaches its end time t=T3, for example, T3=420 seconds, all PWM outputs are immediately turned off and all discharge circuits are disconnected. Subsequently, the main control chip reads the cumulative conduction time t of each cell to be balanced. e and Δt p From t e The final effective equilibrium duration t is obtained by subtracting from the middle. a =t e Δt p , with t a Based on this, the actual balanced charge Q of the cell in this cycle is obtained by multiplying the cell's equalization current I, duty cycle D, and efficiency η. a =I×D×t a ×η.

[0042] In one specific embodiment, the execution step of collecting the surface temperature of each cell to be balanced during the third time period of the half-online cycle and comparing it with a temperature safety threshold, and when the surface temperature of any cell to be balanced exceeds the temperature safety threshold, shutting down the PWM control signal of the cell to be balanced and cutting off the discharge circuit can specifically include the following steps: In the third period of the semi-online cycle, the surface temperatures of the cells to be balanced are collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced is greater than or equal to the temperature safety threshold, the PWM control signal corresponding to the cell to be balanced is turned off and the balancing circuit of the cell is cut off. The temperature protection flag bit of the corresponding cell to be balanced is set in the status register, and the corresponding cell to be balanced is added to the temperature monitoring list. When the surface temperature of the corresponding cell to be balanced in the temperature monitoring list drops below the temperature recovery threshold, the temperature protection flag bit of the corresponding cell to be balanced is cleared, and the remaining charge to be released and the remaining balancing duration of the corresponding cell to be balanced are calculated, and it is judged whether to restart the discharge circuit of the corresponding cell to be balanced.

[0043] In this embodiment, in the third period of the semi-online cycle, the main control chip starts the temperature monitoring task and polls the NTC sensors of all cells to be balanced at a fixed interval Δt to obtain the current surface temperature T in real time, and compares T with the preset temperature safety threshold T s When it is detected that T≥T for a certain cell s , for example, T s =45°C, an interrupt operation is immediately executed to turn off the PWM control signal of the cell, turn off its MOSFET to cut off the discharge path formed by the balancing resistor, write the temperature protection flag 1 in the corresponding status register bit, and at the same time add the cell number to the temperature monitoring list to mark that it is currently in a thermal interruption state. Periodic temperature sampling and judgment are performed on all cells in the temperature monitoring list at the same sampling interval. If the temperature of a certain cell drops below the temperature recovery threshold T r , for example, T r =40°C, it is determined that the cell has returned to the controllable temperature range, the main control chip clears its temperature protection flag bit, and re-evaluates whether the cell has remaining balancing requirements. According to the target charge to be released Q t and the released charge Q a , the difference calculation ΔQ = Q t Q a is performed, and the balancing current I = V÷R is calculated in combination with its corresponding voltage V and resistance R, and then the remaining balancing duration T = ΔQ÷(I×η) is deduced in combination with the balancing efficiency η. Subsequently, it is judged whether the difference Δt between the current system time t and the upper limit T3 of the third period is greater than or equal to T. If Δt≥T, the PWM control module of the cell is immediately restarted, and the duty cycle is set to D = 1.0 to resume the balancing operation at full duty cycle; if Δt<T, the main control chip sets the duty cycle to D = T÷Δt to enable it to complete the balancing release task within the remaining time, ensuring the thermal safety of the cells and the responsiveness, reparability and control closed-loop of the energy release process throughout the cycle.

[0044] In one specific embodiment, the process of performing step 400 may specifically include the following steps: Divide the actual balanced charge by the corresponding first capacity parameter to obtain the state of charge drop, and subtract the corresponding state of charge drop from the first state of charge to obtain the second state of charge. Divide the amount of charge charged in a cycle by the increment of the state of charge in the current half-online cycle to obtain the equivalent capacity value. Take a weighted average of the equivalent capacity value and the first capacity parameter to obtain the second capacity parameter. The second state of charge and the second capacity parameter are used as the initial state of charge and initial capacity parameter for the next half of the online cycle, and the first time period of the next half of the online cycle is started to re-acquire charging data.

[0045] In this embodiment, the state update phase begins immediately after the third time period ends, and the main control chip reads the actual charge Q released by each cell to be balanced during this cycle. a Q a Dividing by the first capacity parameter Q of the corresponding cell, we obtain the decrease in state of charge ΔS=Q caused by this balancing process. a ÷Q, subtract ΔS from the first state of charge S1 recorded at the end of the previous cycle, and execute S2=S1. ΔS yields the second state of charge after equalization correction. For cells not involved in equalization, S2 is directly copied from S1 without correction. This is based on the difference between the periodic charge Q1 and the initial and final states of charge, ΔS'=S2, obtained statistically in the first time period. S0 performs equivalent capacity estimation, calculating the equivalent capacity value Q' of the cell in the current cycle using the formula Q'=Q1÷ΔS'. Q' reflects the actual charging capacity within a unit state-of-charge variation range. To ensure smooth update of capacity parameters, the main control chip uses a weighted average strategy to merge Q' with the old capacity Q, forming a new second capacity parameter Q2=α×Q+β×Q', where α and β are preset weighting coefficients, such as α=0.9 and β=0.1. The updated Q2 reflects the balance trend between historical capacity and observed capacity in the current cycle. S2 and Q2 are written into the initial state buffer of the next half-online cycle, and the counting registers related to time, integration, and sampling in the main control chip are reset. Simultaneously, the cycle controller is restarted, and the system enters the first time period of the next cycle and begins sampling at a new Δt interval. Based on the new Q2 and S2 parameters, synchronous acquisition of voltage, current, and temperature and integration of state of charge are performed again.

[0046] The lithium battery BMS balancing method in the embodiments of the present invention has been described above. The lithium battery BMS balancing device in the embodiments of the present invention is described below. Please refer to [link / reference]. Figure 6One embodiment of the lithium battery BMS equalization device in this invention includes: The acquisition module 601 is used to acquire the first state of charge and the amount of charge charged in the cycle for each cell during the first period of the semi-online cycle. Calculation module 602 is used to determine the cells to be balanced and calculate the balancing duty cycle parameters based on the first state of charge during the second time period of the half-online cycle. The discharge equalization module 603 is used to drive the equalization circuit of each cell to be equalized to perform discharge equalization and count the actual equalization charge in the third period of the half-online cycle according to the equalization duty cycle parameter. The startup module 604 is used to update the first state of charge based on the actual balanced charge amount to obtain the second state of charge, calculate the second capacity parameter according to the periodic charge amount, and start the first period of the next half of the online cycle based on the second state of charge and the second capacity parameter.

[0047] Through the synergistic cooperation of the above components, this invention divides the charging process into multiple semi-online cycles of fixed duration. Each cycle is divided into a data acquisition period, a parameter calculation period, and an equalization execution period according to the time proportion. This achieves the time decoupling of charging state estimation and equalization control, realizes continuous tracking of cell state and dynamic correction of parameters, and improves the response frequency to dynamic changes in cell state during charging compared to offline equalization.

[0048] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0049] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an electronic device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0050] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lithium battery BMS equalization method, characterized in that, include: During the first period of the semi-online cycle, the first state of charge and the amount of charge charged in the cycle for each cell are obtained. During the second period of the half-online cycle, the cells to be balanced are determined based on the first state of charge and the balancing duty cycle parameters are calculated. During the third period of the half-online cycle, the equalization circuit of each cell to be equalized is driven to perform discharge equalization according to the equalization duty cycle parameter and the actual equalization charge is counted. The first state of charge is updated based on the actual balanced charge amount to obtain the second state of charge, and the second capacity parameter is calculated according to the periodic charge amount. The first period of the next half of the online cycle is started based on the second state of charge and the second capacity parameter.

2. The lithium battery BMS equalization method according to claim 1, characterized in that, Also includes: Read the historical capacity parameters and historical state of charge of each cell, and configure the fixed sampling period and equalization start threshold of the BMS system; Set the total duration of the semi-online cycle in the BMS system; The total duration of the semi-online cycle is divided into a first time period for collecting charging data, a second time period for calculating equalization parameters, and a third time period for performing equalization control according to a preset time ratio. The duration of the third time period is greater than the sum of the durations of the first and second time periods.

3. The lithium battery BMS equalization method according to claim 1, characterized in that, During the first period of the semi-online cycle, the first state of charge and the amount of charge charged in the cycle for each cell are acquired, including: During the first period of the semi-online cycle, the terminal voltage and charging current of each cell are collected according to a fixed sampling period; The state of charge increment is calculated based on the charging current and the charging coulombic efficiency. The state of charge increment is accumulated with the first capacity parameter of each cell and the state of charge at the previous sampling point to obtain the real-time state of charge, and the real-time state of charge of each cell is taken as the first state of charge at the end of the first time period. The amount of charge charged during the cycle is calculated based on the charging current and the fixed sampling period.

4. The lithium battery BMS balancing method according to claim 1, characterized in that, In the second time period of the half-online cycle, the cells to be balanced are determined based on the first state of charge, and the balancing duty cycle parameters are calculated, including: In the second time period of the semi-online cycle, the average state of charge and the state of charge deviation are calculated based on the first state of charge. The state of charge deviation is compared with a preset deviation threshold to determine whether to initiate the equalization control process. When the equalization control process is started, the cells are traversed and the cells with the first state of charge higher than the average state of charge are selected as cells to be equalized. The difference between the first state of charge and the average state of charge of each cell to be equalized is multiplied by the first capacity parameter of the corresponding cell to obtain the target amount of released charge. The required balancing time for each cell to be balanced is calculated based on the target charge release amount. The required balancing time for each cell to be balanced is compared with the available time of the third time period to obtain the balancing duty cycle parameter of each cell to be balanced.

5. The lithium battery BMS equalization method according to claim 4, characterized in that, The state of charge deviation is compared with a preset deviation threshold to determine whether to initiate the equalization control process, including: The state of charge deviation with the largest value is taken as the maximum deviation value, and the state of charge deviation with the smallest value is taken as the minimum deviation value. Calculate the target deviation value based on the maximum deviation value and the minimum deviation value; The target deviation value is compared with a preset threshold. When the target deviation value is greater than the preset threshold, the equalization control process is initiated; when the target deviation value is less than or equal to the preset threshold, the equalization control process is skipped and the next half of the online cycle is started directly.

6. The lithium battery BMS balancing method according to claim 5, characterized in that, The required balancing time for each cell to be balanced is calculated based on the target released charge amount. The required balancing time for each cell to be balanced is compared with the available time of the third time period to obtain the balancing duty cycle parameters for each cell to be balanced, including: Obtain the cell voltage of each cell to be balanced at the end of the first time period, and divide the cell voltage by the balancing resistor to obtain the balancing current of each cell to be balanced. Divide the target released charge by the product of the corresponding equalization current and the equalization efficiency coefficient to obtain the required equalization time; The required balancing durations are summed to obtain an accumulated value, and the accumulated value is compared with the available duration of the third time period; When the accumulated value is less than or equal to the available duration, the equalization duty cycle parameter of each cell to be equalized is set to full duty cycle. When the accumulated value is greater than the available duration, the equalization duty cycle parameter is calculated based on the ratio of the required equalization duration to the single-path allocation duration.

7. The lithium battery BMS balancing method according to claim 1, characterized in that, During the third period of the half-online cycle, the equalization circuits of each cell to be equalized are driven to perform discharge equalization according to the equalization duty cycle parameters, and the actual equalization charge is counted, including: The PWM control signal is generated based on the equalization duty cycle parameter to drive the MOSFET switch of each cell to be equalized. By controlling the MOSFET to turn on and off, the equalization resistor is connected to both ends of the cell to form a discharge circuit. During the third period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced exceeds the temperature safety threshold, the PWM control signal of the cell to be balanced is turned off and the discharge circuit is cut off. At the end of the third time period, the effective balancing time of each cell to be balanced is obtained and the temperature protection pause time is deducted. The effective balancing time is then multiplied by the corresponding balancing current, balancing duty cycle parameter and balancing efficiency coefficient to obtain the actual balancing charge.

8. The lithium battery BMS equalization method according to claim 7, characterized in that, During the third time period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with a temperature safety threshold. When the surface temperature of any cell to be balanced exceeds the temperature safety threshold, the PWM control signal of the cell to be balanced is turned off and the discharge circuit is cut off, including: During the third time period of the semi-online cycle, the surface temperature of each cell to be balanced is collected and compared with the temperature safety threshold. When the surface temperature of a cell to be balanced is greater than or equal to the temperature safety threshold, the PWM control signal corresponding to the cell to be balanced is turned off and the balancing circuit of the cell is cut off. The temperature protection flag of the cell to be balanced is set in the status register and the cell to be balanced is added to the temperature monitoring list. When the surface temperature of the corresponding cell to be balanced in the temperature monitoring list drops below the temperature recovery threshold, the temperature protection flag of the corresponding cell to be balanced is cleared, the remaining amount of charge to be released and the remaining balancing time of the corresponding cell to be balanced are calculated, and it is determined whether to restart the discharge circuit of the corresponding cell to be balanced.

9. The lithium battery BMS equalization method according to claim 1, characterized in that, The first state of charge is updated based on the actual balanced charge amount to obtain a second state of charge, and a second capacity parameter is calculated based on the periodic charge amount. The first time period of the next half of the online cycle is then initiated based on the second state of charge and the second capacity parameter, including: Divide the actual balanced charge by the corresponding first capacity parameter to obtain the state of charge drop, and subtract the corresponding state of charge drop from the first state of charge to obtain the second state of charge. Divide the amount of charge charged in the cycle by the increment of the state of charge in the current half-online cycle to obtain the equivalent capacity value. Take a weighted average of the equivalent capacity value and the first capacity parameter to obtain the second capacity parameter. The second state of charge and the second capacity parameter are used as the initial state of charge and initial capacity parameter for the next half of the online cycle, and the first time period of the next half of the online cycle is started to re-acquire charging data.

10. A lithium battery BMS balancing device, characterized in that, A method for performing the lithium battery BMS balancing method as described in any one of claims 1-7, comprising: The acquisition module is used to acquire the first state of charge and the amount of charge charged in the cycle for each cell during the first period of the semi-online cycle. The calculation module is used to determine the cells to be balanced and calculate the balancing duty cycle parameters based on the first state of charge during the second time period of the half-online cycle. The discharge equalization module is used to drive the equalization circuit of each cell to be equalized to perform discharge equalization and count the actual equalization charge amount in the third period of the half-online cycle according to the equalization duty cycle parameter. The startup module is used to update the first state of charge based on the actual balanced charge amount to obtain the second state of charge, calculate the second capacity parameter according to the periodic charge amount, and start the first period of the next half of the online cycle based on the second state of charge and the second capacity parameter.

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