Control method of battery equalization control circuit

Abstract

The invention discloses a control method of a battery equalization control circuit. The control method of the battery equalization control circuit comprises the following steps: sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery in the battery pack and the current of each target battery in the battery pack; the sampling voltage of the battery pack, the sampling current of the battery pack, the initial sampling voltage of each target battery and the sampling current of each target battery are obtained; synchronously correcting the initial sampling voltages of all the target batteries in the battery pack, and determining whether the sum of the voltages obtained by synchronously correcting the initial sampling voltages of all the target batteries is within a set normal range or not; determining whether the initial sampling voltage of each target battery is within a preset battery voltage normal range or not after synchronous correction; and carrying out balance control on the voltage of the target battery.

Description

Technical Field

[0001] The present application relates to the field of battery balancing systems, and in particular to a control method for a battery balancing control circuit. Background Art

[0002] Equipment in industrial, banking, data centers, communication base stations and other scenarios have high requirements for power supply reliability. When the power grid is in an abnormal state such as a power outage, backup batteries are often needed as energy storage devices to continuously power the equipment. The application of this backup energy has high requirements for battery reliability. Although high-energy-density batteries such as lithium batteries are increasingly widely used, mature and safe batteries are still generally used to form battery packs for safety reasons, such as lead-acid batteries or lead-carbon batteries.

[0003] A battery pack is usually made up of multiple batteries connected in series. The rated voltage of a single battery is commonly 2V, 6V, 12V, etc. The voltage of a single lead-acid battery is about 2V. It is generally believed that the voltage of a single lead-acid battery is about 2V. low ~V high The voltage between is safe. high or below V low , which may damage the battery. For a 2V lead-acid battery, V low Generally considered to be 1.7V, V high It is generally considered to be 2.35V. 6V and 12V batteries are generally made of 2V batteries in series. Different batteries have different V low With V high The following uses a 2V lead-acid battery as an example to explain the impact of abnormal conditions such as power outages on backup batteries. Other batteries are similar.

[0004] Figure 1 The figure shows a simple equivalent model of a battery. In the case of DC or low frequency, R 1 , R 2 are the first equivalent series impedance and the second equivalent series impedance respectively, R 3 is the equivalent parallel impedance. R 1 , R 2 It represents the internal resistance of the battery. R 3 Related to battery leakage current. This model states that as a battery sits, its charge gradually decreases.

[0005] FIG. 2A to FIG. 4B The diagram shows several working states of the battery pack. The DC power supply provides energy to the battery pack and the load. The battery pack is composed of n 2V lead-acid batteries connected in series. For the convenience of explanation, it is assumed that the load is a constant resistance.i load is the load current; i battery is the battery current; i changer is the current output by the DC power supply; BAT 1 , BAT 2 , BAT 3 ， ..., BAT n They are the 1st battery, the 2nd battery, the 3rd battery, ..., the nth battery; v 1 , v 2 , v 3 ， ..., v n They are the voltages of the first battery, the second battery, the third battery, ..., the nth battery from top to bottom in the figure; v battery Indicates the voltage of the DC power supply. t indicates time. There is generally an equivalent impedance in the battery circuit, which is composed of line resistance, contact resistance, etc. in series. For DC power, it can be approximately regarded as resistance. R s Indicates; equivalent impedance R s The voltage used v Rs express.

[0006] Specifically, Figure 2A and Figure 2B The diagram shows that when the grid loses power, the battery discharges externally, allowing the equipment to continue working, which is called the discharge state. Figure 2B It can be seen that when the battery is discharged, the battery voltage gradually decreases. i battery With Figure Figure 2A The sign direction is opposite, so it is a negative current, and the value is the same as i load same.

[0007] Figure 3A and Figure 3B It shows the state in which the battery is charged by the DC power supply after the power grid returns to normal, which is called the equalization charging state. Figure 3A The DC power supply provides current to the load i load , and charge the battery, so there is i changer = ibattery + i load As the battery is charged, its voltage gradually increases.

[0008] When the voltage of the battery pack reaches the set full threshold, the battery pack is considered fully charged. At this time, if the DC power supply is disconnected, the battery pack is in a shelved state, and its power will gradually decrease due to leakage. In most cases, the battery pack is not used as a backup power source, so the battery may be in a low-power state or even damaged due to deep discharge, which will cause the battery pack to fail to enter normally. Figure 2A and Figure 2B The external discharge state shown in the figure causes the powered equipment to fail to work, resulting in significant losses.

[0009] In order to solve this problem, when the battery pack is fully charged, the DC power supply does not leave the battery pack and maintains a certain voltage. This state is called floating charge state, and the current flowing through the battery pack at this time is called floating charge current. Figure 4A and Figure 4B shown. Figure 4A The DC power supply provides current to the load i load , and charge the battery, so there is i changer = i battery + i load . Figure 4A and Figure 4B The battery status shown is similar to Figure 3A and Figure 3B The differences in the battery status shown are: Figure 4A and Figure 4B When the battery shown is in floating charge state, the voltage of the battery pack is stable and consistent with the DC power supply. At this time, the current flowing into the battery is very small.

[0010] Figure 5 The present invention is an embodiment of a statistical table of battery voltages of a battery pack in a floating charge state. Figure 4A and Figure 4B In the floating charge state shown in the figure, the voltage statistics of n batteries in the battery pack are as follows: Figure 5 shown. Figure 5 The horizontal axis in the middle represents the battery voltage in volts. If the battery below 1.95V has m 1 The number of batteries with a voltage greater than 1.95V and less than 2.00V is m 2 The number of batteries with a voltage greater than 2.00V and not exceeding 2.05V is m 3The number of batteries with a voltage greater than 2.05V and not exceeding 2.10V is m4, the number of batteries with a voltage greater than 2.10V and not exceeding 2.15V is m5, the number of batteries with a voltage greater than 2.15V and not exceeding 2.20V is m6, the number of batteries with a voltage greater than 2.20V and not exceeding 2.25V is m7, the number of batteries with a voltage greater than 2.25V and not exceeding 2.30V is m8, the number of batteries with a voltage greater than 2.30V and not exceeding 2.35V is m9, and the number of batteries with a voltage greater than 2.35V and not exceeding 2.40V is m 10 It can be considered that the voltage greater than 2.20V and not exceeding 2.25V is the optimal range of battery voltage. m 7 batteries are in this range. Voltages not exceeding 2.00V and greater than 2.35V are considered abnormal voltage ranges. The number of batteries satisfies equation (1), and the battery voltage relationship satisfies equation (2).

[0011]

[0012]

[0013] in, v k Indicates k The voltage of the battery; v RS express n The total equivalent resistance of the battery.

[0014] When the voltages of all cells in the battery pack are within the normal voltage range, the battery pack can be considered to be in a healthy state. Once a cell with a cell voltage within the abnormal voltage range appears, the battery pack can be considered to be in an unhealthy state.

[0015] In the floating charge state, for batteries connected in series, due to individual differences in batteries, it is difficult for the voltages of each battery to be in the optimal voltage range; as time goes by, this voltage difference may become larger and larger, and even some battery voltages may enter the optimal voltage range. Figure 5 The abnormal voltage range shown causes the battery pack to be unhealthy at this time; once the battery enters the discharge state, the discharge duration will be shortened, resulting in failure to meet the backup power supply requirements.

[0016] Therefore, a control method for a battery balancing control circuit is needed. Summary of the invention

[0017] An advantage of the present application is that it provides a control method for a battery balancing control circuit, wherein the control method for the battery balancing control circuit enables the voltage of each target battery to be reliably sampled and balanced, thereby extending the life of the battery pack.

[0018] Another advantage of the present application is that it provides a control method for a battery balancing control circuit, wherein the control method for the battery balancing control circuit can improve the reliability of voltage data of a target battery to a certain extent.

[0019] According to one aspect of the present application, a control method for a battery balancing control circuit is provided, which comprises the steps of: Sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery in the battery pack, and the current of each target battery in the battery pack to obtain a sampled voltage of the battery pack, a sampled current of the battery pack, an initial sampled voltage of each target battery, and a sampled current of each target battery; Synchronously correct the initial sampled voltages of all target batteries in the battery pack, and determine whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is within a set normal range; wherein, Calculate the voltage of each target battery after the initial sampling voltage is synchronously corrected; where, V k ( t nj ) indicates the k The target battery j The voltage after synchronous correction of the initial sampling voltage; V k ( t kj ) indicates the k The target battery t kj The moment j The initial sampling voltage of the time; ω Indicates the correction coefficient of the sampling voltage based on time and sampling error, which is a preset value; t nj Indicates n Target battery No. j The time of subsampling; t kj Indicates k Target battery No. j The time of subsampling; n Indicates the number of all target batteries; Determine whether the voltage of each target battery after synchronous correction of the initial sampled voltage is within a preset normal range of battery voltage; and The voltage of the target battery is balanced and controlled.

[0020] In one embodiment of the control method of the battery balancing control circuit described in the present application, in the process of sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery in the battery pack, and the current of each target battery in the battery pack, the current of the battery pack, the voltage of the battery pack, and the current of the target battery are sampled by a sampling unit of the battery balancing control circuit to obtain a sampled current of the battery pack, a sampled voltage of the battery pack, and a sampled current of the target battery; the voltage of each target battery is sampled by the balancing unit of the battery balancing control circuit to obtain an initial sampled voltage of each target battery.

[0021] In one embodiment of the control method of the battery balancing control circuit described in the present application, the initial sampled voltages of all target batteries in the battery pack are synchronously corrected, and in the process of determining whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is within a set normal range, when the difference between the sum of the voltages of the initial sampled voltages of all target batteries after the synchronous correction and the normal value of the battery pack voltage is less than a preset error threshold, the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is within the set normal range; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries after the synchronous correction and the normal value of the battery pack voltage is greater than or equal to the preset error threshold, it is determined that the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is not within the set normal range.

[0022] In one embodiment of the control method of the battery balancing control circuit according to the present application, in the process of determining whether the voltage of each target battery after synchronous correction of the initial sampled voltage is within the preset normal range of the battery voltage, when When k The target battery j The voltage after synchronous correction of the initial sampling voltage is assigned to the j times before ( j -1) times of the target battery's initial sampled voltage after synchronous correction, and control the count value of the sampled voltage alarm counter to add 1. When the count value of the sampled voltage alarm counter is greater than the preset number threshold N When k target batteries failed; among them, V kj Indicates the battery pack k The target battery j The voltage after synchronous correction of the initial sampling voltage; V low Indicates the voltage low threshold; Indicates the voltage error threshold; ,in,V pred Indicates j times before ( j -1) times the average voltage of the initial sampled voltage of the target battery after synchronous correction; V kM Indicates k The target battery M The sampling voltage of the time.

[0023] In one embodiment of the control method of the battery balancing control circuit described in the present application, the control method of the battery balancing control circuit also includes the steps of: detecting whether the battery pack is in a floating charge state; detecting whether the initial sampling voltage of each target battery is stable and whether the sampling current of each target battery is stable; and determining whether the difference between the sum of the initial sampling voltages of all target batteries and the sampling voltage of the battery pack is less than a preset difference threshold.

[0024] In one embodiment of the control method of the battery balancing control circuit described in the present application, during the process of balancing the voltage of the target battery, it is determined whether the voltage of the target battery after the synchronous correction is within the optimal voltage range based on the difference between the voltage of the initial sampled voltage of each target battery after the synchronous correction and the target voltage of the target battery.

[0025] In one embodiment of the control method of the battery balancing control circuit described in the present application, when the difference between the voltage after the synchronous correction of the initial sampled voltage of each target battery and the target voltage of the target battery is less than a preset voltage difference threshold and the target voltage of the target battery is in an optimal voltage interval, it is determined that the voltage after the synchronous correction of the initial sampled voltage of the target battery is in the optimal voltage interval; when the difference between the voltage after the synchronous correction of the initial sampled voltage of each target battery and the target voltage of the target battery is greater than or equal to the preset voltage difference threshold and the target voltage of the target battery is in the optimal voltage interval, it is determined that the voltage after the synchronous correction of the initial sampled voltage of the target battery is not in the optimal voltage interval, and it is detected whether the sampling time of the initial sampled voltage of the target battery is within the preset balancing control time.

[0026] In one embodiment of the control method of the battery balancing control circuit described in the present application, when the synchronously corrected sampled voltage of the target battery is not in the optimal voltage range and the sampling time of the initial sampled voltage of the target battery is within the preset balancing control time, the voltage of the target battery is adjusted by the balancing unit of the battery balancing control circuit.

[0027] In one embodiment of the control method of the battery balancing control circuit described in the present application, in the process of adjusting the voltage of the target battery by the balancing unit of the battery balancing control circuit, the current of the controllable discharge circuit of the balancing unit is adjusted, and then the current of the target battery is adjusted to adjust the voltage of the initial sampled voltage of the target battery after synchronous correction to be close to the optimal voltage range.

[0028] In one embodiment of the control method of the battery balancing control circuit described in the present application, the control method of the battery balancing control circuit also includes the step of uploading the voltage after synchronous correction of the initial sampled voltage of the target battery, the actual floating charge current of the target battery, the current of the controllable discharge circuit, and the sampled temperature to the convergence unit.

[0029] Further objectives and advantages of the present application will be fully reflected through understanding of the following description and drawings.

[0030] These and other objects, features and advantages of the present application are fully reflected in the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0032] Figure 1 The figure shows a simple equivalent model of a battery.

[0033] Figure 2A The diagram shows the schematic diagram of the current flow in various parts of the circuit when the battery is in a discharged state.

[0034] Figure 2B The figure shows the waveform diagram of the current in various parts of the circuit when the battery is in a discharged state.

[0035] Figure 3A The figure shows a schematic diagram of the current flow in various parts of the circuit when the battery is in the equalization charging state.

[0036] Figure 3B The figure shows the waveform diagram of the current in various parts of the circuit when the battery is in the equalization charging state.

[0037] Figure 4A The diagram shows the current flow in various parts of the circuit when the battery is in a floating charge state.

[0038] Figure 4B The figure shows the waveform diagram of the current in various parts of the circuit when the battery is in a floating charge state.

[0039] Figure 5 The figure shows a schematic diagram of a statistical table of battery voltage in an example when the battery is in a floating charge state.

[0040] Figure 6 FIG. 1 is a schematic diagram of a battery balancing control circuit according to an embodiment of the present application.

[0041] Figure 7 Schematic diagram showing the sources of error in sampling time.

[0042] Figure 8 The figure shows a partial flow chart of a sampling process of a battery balancing control circuit according to an embodiment of the present application.

[0043] Fig. 9 The figure shows a flow chart of a process of sampling the voltage of a target battery by a battery balancing control circuit according to an embodiment of the present application.

[0044] Fig.10 The figure shows a block diagram of a balancing unit of a battery balancing control circuit according to an embodiment of the present application.

[0045] Fig.11 The figure shows a flow chart of a process of balancing the voltage of a target battery by a battery balancing control circuit according to an embodiment of the present application.

[0046] Fig.12 The figure shows a block diagram of a controllable discharge circuit of a battery balancing control circuit according to an embodiment of the present application.

[0047] Fig.13 The figure illustrates a flow chart of a control method of a battery balancing control circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] Below, the exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the exemplary embodiments described here.

[0049] It is understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number. "Multiple" means greater than or equal to two.

[0050] Although ordinals such as "first," "second," and the like will be used to describe various components, those components are not limited herein. The term is used only to distinguish one component from another. For example, a first component may be referred to as a second component, and likewise, a second component may be referred to as a first component without departing from the teachings of the present application. The term "and / or" as used herein includes any and all combinations of one or more associated listed items.

[0051] The terms used herein are only used for the purpose of describing various embodiments and are not intended to be limiting. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates an exception. It will also be understood that the terms "including" and / or "having" when used in this specification specify the presence of the described features, numbers, steps, operations, components, elements, or combinations thereof, without excluding the presence or addition of one or more other features, numbers, steps, operations, components, elements, or combinations thereof.

[0052] like Figures 6 to 12 As shown, a battery balancing control circuit according to an embodiment of the present application is illustrated. The battery balancing control circuit is used to balance the voltages of multiple target batteries 200 of a battery pack, wherein the multiple target batteries 200 are connected in series. Figure 6 As shown, the battery balancing control circuit includes a DC power supply 10 , a current sensor 20 , a sampling unit 40 , a balancing component 50 and a convergence unit 60 . The DC power supply 10 is suitable for being connected to a power grid and to a plurality of target batteries 200, and is used to convert the power of the power grid into DC power; the current sensor 20 is suitable for being connected in series with a plurality of target batteries 200, and is used to sample the current flowing through the battery pack; the sampling unit 40 is connected to the current sensor 20 and the DC power supply 10, and is used to sample the charging voltage and the charging current provided by the DC power supply 10 to the battery pack; the balancing component 50 includes a plurality of balancing units 51, each of which is suitable for being connected in parallel to a corresponding target battery 200, and is suitable for sampling the voltage at both ends of the corresponding target battery 200; the convergence unit 60 is connected to the sampling unit 40 and the plurality of balancing units 51, and is used to receive signals from the sampling unit 40 and the plurality of balancing units 51, so as to obtain target battery 200 data, for example, the sampled current of each target battery 200, the initial sampled voltage of each target battery 200, the sampled current of the battery pack, and the sampled voltage of the battery pack.

[0053] In one embodiment of the present application, the aggregation unit 60 is adapted to be connected to the cloud platform 300 , and is used to upload the target battery 200 data to the cloud platform 300 .

[0054] exist Figure 1In the battery model shown, when the floating charge current flowing into the battery is equal to the leakage current, the battery voltage no longer changes, and the battery reaches a steady state; however, in this steady state, the battery voltage often behaves like Figure 5 In order to adjust the battery voltage to Figure 5 The optimal voltage range shown requires the current flowing into the battery to be changed by the balancing unit 51 .

[0055] In the embodiments of the present application, Fig.10 As shown, the balancing unit 51 includes a controllable discharge circuit 511, a current detection circuit 512, a voltage detection circuit 517, a temperature detection circuit 513, a micro control unit circuit 514 (i.e., an MCU circuit), an isolated power supply circuit 515, and an isolated communication circuit 516. The controllable discharge circuit 511, the current detection circuit 512, the temperature detection circuit 513, and the isolated communication circuit 516 are connected to the micro control unit circuit 514. The controllable discharge circuit 511 is connected in series with the current detection circuit 512 and forms a voltage control loop with the target battery 200. The controllable discharge circuit 511 is configured to adjust the current flowing through the controllable discharge circuit 511; the current detection circuit 512 is configured to detect the current of the controllable discharge circuit 511. The temperature detection circuit 513 is used to detect the sampling temperature. The isolated communication circuit 516 is used to detect the voltage of the target battery 200.

[0056] like Fig.12As shown, the controllable discharge circuit 511 includes a driving unit 5111, a sampling feedback unit 5112 and a discharge switch array 5113. The driving unit 5111 is connected to the micro control unit circuit 514, and is used to receive the control signal of the micro control unit circuit 514, and drive the discharge switch array 5113 based on the signal received from the micro control unit circuit 514. The discharge switch array 5113 is connected to the driving unit 5111 and the sampling feedback unit 5112, and includes a plurality of discharge switches 51131; the plurality of discharge switches 51131 are connected in parallel. The discharge switch 51131 can be a semiconductor device such as a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), etc. The sampling feedback unit 5112 is composed of a series of sampling elements (such as sampling resistors, Hall, current transformers, etc.), comparators, operational amplifiers, voltage references and other components, and can sample the discharge current of each of the discharge switches 51131, and feed it back to the driving unit 5111 and then to the micro control unit circuit 514. The driving unit 5111 adjusts the number of closures of the discharge switches 51131 in the discharge switch array 5113 or the size of the discharge current according to the driving signal of the micro control unit circuit 514 and the feedback signal of the sampling feedback unit 5112, thereby achieving the effect of adjusting the size of the discharge current of the controllable discharge circuit 511.

[0057] In particular, the applicant of the present application has found that in the process of balancing the voltage of the target battery 200, the reliability of the voltage data of the target battery 200 and the health status of the battery pack must be ensured first. Accordingly, the present application has designed a specific sampling method of the target battery 200 to ensure the reliability of the voltage data of the target battery 200. The design concept of the sampling method of the initial sampling voltage of the target battery 200 of the present application is described below.

[0058] Specifically, if the initial sampling voltage of the target battery 200 obtained by directly collecting V k ( k =1, 2, 3, ..., n ) is the final sampling voltage to determine whether the voltage of the target battery 200 is within the abnormal range. In the case of communication abnormality or sampling abnormality, the real-time voltage status of the target battery 200 is difficult to be accurately determined.

[0059] In engineering practice, due to the influence of sampling error, equivalent resistance in the loop, synchronization of sampling time and other factors, the sum of the voltages of all target batteries 200 collected by the convergence unit 60 is often not equal to the voltage of the battery pack.

[0060] Without considering sampling error and sampling time synchronization, the ideal voltage relationship should be: ;in, V k Indicates k An initial sampling voltage of a target battery 200; V RS express n The total equivalent resistance of the target battery 200; V battery It represents the charging voltage provided by the DC power supply 10 to the battery pack.

[0061] Figure 7 shows the sources of error in the sampling time, where V 1 , V 2 , V 3 ， ..., V n They are 1st, 2nd, 3rd, ..., n An initial sampling voltage of a target battery 200; t 11 , t 21 , ..., t n1 They are 1st, 2nd, 3rd, ..., n The time of first sampling of each target battery 200; t 12 , t 22 , ..., t n2 They are 1st, 2nd, 3rd, ..., n The time of the second sampling of the target battery 200; t 1j , t 2j , ..., t nj They are 1st, 2nd, 3rd, ..., n Target battery 200 j Taking the data sampled for the first time as an example, the aggregation unit 60 collects the data sampled for the first time. n The initial sampling voltages of the target batteries 200 are V1 ( t 11 ), V 2 ( t 21 ), ..., V n ( t n1 ), the sampling times are t 11 , t 21 , ..., t n1 , because of the intervals between sampling times and the time difference in communication with the gateway, it is obviously impossible to achieve synchronous sampling of the voltages of each target battery 200, that is, it is impossible to sample the voltages of each target battery 200 at the same time. Therefore, if the initial sampling voltage of the directly measured target battery 200 is used as the final sampling voltage, misjudgment is prone to occur when the voltage fluctuates.

[0062] The present application proposes that in the process of sampling the voltage of the target battery 200, the initial sampled voltages of all target batteries 200 can be synchronously corrected, so as to subsequently judge the health status of the battery pack based on whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries 200 is within a set normal range.

[0063] In the process of synchronously correcting the initial sampled voltages of all target batteries 200, the initial sampled voltages of all target batteries 200 in the battery pack are corrected to be the same as the voltage of the last target battery 200 (i.e., the first target battery 200). n The "sampled voltage that is synchronized in time with the last target battery 200 for voltage acquisition each time" corresponding to each target battery 200 means: the corresponding voltage of each target battery 200 at the same sampling time as the last target battery 200 for voltage acquisition each time. It should be understood that since the voltage sampling times of each battery are spaced apart from each other, it is impossible to achieve true voltage sampling time synchronization. Therefore, the "sampled voltage that is synchronized in time with the last target battery 200 for voltage acquisition each time" corresponding to each target battery 200 is a calculated value, which can be obtained by a specific calculation method.

[0064] Specifically, each target battery 200 is subjected to the first j The relationship between the initial sampling voltages of the target voltages obtained by sampling is: ;in, V k ( tkj ) indicates the k Target battery 200 in t kj The moment j The initial sampling voltage of the time; express n Target battery 200 t kj The moment j The sum of the initial sampling voltages; Represents the error voltage; V battery ( t batteryj )express n Target battery 200 t kj The moment j The actual value corresponding to the sum of the initial sampling voltages of times; n represents the number of all target batteries 200. If the voltage fluctuation of a single target battery 200 is large, and t 11 , t 21 , ..., t j1 The larger the discreteness, the larger the error voltage.

[0065] In order to eliminate the voltage error caused by the asynchronous voltage sampling time of multiple target batteries 200 and reduce the error voltage of the entire battery pack formed by multiple target batteries 200, the initial sampling voltage of each target battery 200 is synchronously corrected. After the voltage of all target batteries 200 in the battery pack is synchronously corrected, it can be obtained: ;in, V k ( t nj ) indicates the k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage is k The first target battery 200 and the last one (i.e., n ) to conduct the j The target battery 200 of the voltage acquisition is synchronized with the j The sampling voltage of the second; ω Indicates the correction coefficient of the sampling voltage based on time and sampling error, which is a preset value; t nj Indicates n Target battery 200 j The time of subsampling; t kj Indicates kTarget battery 200 j The sampling time. Indicates k Target battery 200 j The time of the second sampling is n Target battery 200 j The time interval between subsampling times. The smaller, the k The smaller the voltage error of each target battery 200 due to the asynchronous sampling time is, the smaller the sampling error of the entire battery group is.

[0066] After the initial sampled voltages of all target batteries 200 in the battery pack are synchronously corrected, it is determined whether the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is within a set normal range. In the process of determining whether the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is within the set normal range, the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction are summed, and the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is compared with the normal value of the battery pack voltage; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction and the normal value of the battery pack voltage is less than a preset error threshold, the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is within the set normal range, and the state of the battery pack is healthy; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction and the normal value of the battery pack voltage is greater than or equal to the preset error threshold, it is determined that the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is not within the set normal range, the state of at least some of the target batteries 200 is unhealthy, and the state of the battery pack is unhealthy.

[0067] It can be further determined whether the voltage of each target battery 200 after synchronous correction is within the preset normal battery voltage range. Specifically, in the process of determining whether the voltage of each target battery 200 after synchronous correction is within the preset normal battery voltage range, Fig. 9As shown, when the voltage of a certain initial sampling voltage of a target battery 200 in the battery pack after synchronous correction is far below the low voltage threshold, the voltage of the initial sampling voltage of the target battery 200 after synchronous correction is assigned to a specific value, for example, the average value of the voltages of the initial sampling voltages of the target battery 200 before the current sampling of the target battery 200 after synchronous correction, and the count value of the sampling voltage alarm counter is controlled to increase by 1; when the number of times that the voltage of the initial sampling voltage of the target battery 200 after synchronous correction is far below the low voltage threshold exceeds the preset number threshold, and the count value of the sampling voltage alarm counter is greater than the preset number threshold, it is determined that the voltage of the initial sampling voltage of the target battery 200 after synchronous correction is not within the preset battery voltage normal range, and the state of the target battery 200 is unhealthy and a fault has occurred.

[0068] For example, when the battery pack k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage V k ( t nj ) is well below the voltage low threshold V low When k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage is assigned to the j times before ( j -1) The average voltage of the initial sampled voltage of the target battery 200 after synchronous correction V pred , and controls the count value of the sampling voltage alarm counter to increase by 1, where, , V kM ( t nj ) indicates the k The target battery 200 M The voltage after the initial sampling voltage is synchronously corrected. When the count value of the sampling voltage alarm counter is greater than the preset number threshold N When k The voltage of the target battery 200 after synchronous correction of the initial sampling voltage is not within the preset normal range of battery voltage. k The state of the target battery 200 is unhealthy and a failure has occurred.

[0069] The alarm information of the sampling voltage alarm counter can be reported through the convergence unit 60 and the cloud platform 300, which can reduce the probability of false alarms of the balancing unit 51 for sampling failure, large sampling error, etc. to a certain extent.

[0070] like Figure 8 As shown, before the initial sampling voltages of all target batteries 200 are synchronously corrected, it is possible to determine whether the initial sampling voltage of each target battery 200 is credible. Specifically, first detect whether the battery pack is in a floating charge state; after determining that the battery pack is in a floating charge state, detect whether the initial sampling voltage of each target battery 200 is stable and whether the sampling current of each target battery 200 is stable; then determine whether the difference between the sum of the initial sampling voltages of all target batteries 200 and the sampling voltage of the battery pack is less than a preset difference threshold.

[0071] In the process of detecting whether the battery pack is in a floating charge state, the sampling current and the sampling voltage of the battery pack can be obtained through the convergence unit 60; based on the sampling current and the sampling voltage of the battery pack, it is judged whether the target battery 200 of the battery pack is in a floating charge state. The convergence unit 60 can obtain the sampling current and the sampling voltage of the battery pack through the sampling unit 40. When the battery pack is in a floating charge state, the sampling current of the battery pack is greater than 0, and the sampling current of the battery pack is equal to the charging current provided by the DC power supply 10 to the battery pack; and the current flowing through the battery pack is stable; the sampling current of the battery pack is less than the floating charge current of the battery pack; the sampling voltage of the battery pack is stable and consistent with the floating charge voltage. When the target battery 200 of the battery pack is not in a floating charge state, the sampling current and the sampling voltage of the battery pack are obtained again through the convergence unit 60. When it is determined that the battery pack is in a floating charge state, it is judged whether the initial sampling voltage and sampling current of each target battery 200 are stable.

[0072] In the process of determining whether the initial sampling voltage and sampling current of each target battery 200 are stable, the initial sampling voltage of each target battery 200 and the sampling current of each target battery 200 can be obtained through the convergence unit 60. The initial sampling voltage of each target battery 200 can be collected by the equalization unit 51 and transmitted to the convergence unit 60 by the equalization unit 51; the sampling current of each target battery 200 can be collected by the sampling unit 40 and transmitted to the convergence unit 60 by the sampling unit. When the initial sampling voltage or sampling current of each target battery 200 is unstable, the sampling current and the sampling voltage of the battery group are obtained again through the convergence unit 60.

[0073] When the target battery 200 of the battery pack is in a floating charge state and the voltage of the target battery 200 is stable, it is determined whether the difference between the sum of the initial sampled voltages of all the target batteries 200 and the sampled voltage of the battery pack is less than a preset difference threshold. When the target battery 200 of the battery pack is in a floating charge state and the voltage of the target battery 200 is stable and the difference between the sum of the initial sampled voltages of all the target batteries 200 and the sampled voltage of the battery pack is less than a preset difference threshold, the initial sampled voltage of each target battery 200 is trusted, that is, it is determined that the initial sampled voltage of each target battery 200 is credible. When the difference between the sum of the initial sampled voltages of all the target batteries 200 and the sampled voltage of the battery pack is not less than the preset difference threshold, the sampled current of the battery pack and the sampled voltage of the battery pack are obtained again through the convergence unit 60.

[0074] In the process of balancing the voltage of the target battery 200, the balancing unit 51 samples the voltage of each target battery 200 after synchronous correction of the initial sampling voltage; based on the voltage of each target battery 200 after synchronous correction, the current of the target battery 200 is controlled, thereby controlling the voltage of the target battery 200.

[0075] In the process of performing equalization control on the voltage of the target battery 200, when the battery voltage of the target battery 200 is stable, it can be determined whether the voltage of the initial sampled voltage of the target battery 200 after synchronous correction is in the optimal voltage range based on the deviation degree of the voltage of each target battery 200 after synchronous correction relative to the target voltage of the target battery 200. Specifically, the deviation degree of the voltage of each target battery 200 after synchronous correction relative to the target voltage of the target battery 200 can be determined based on the difference between the voltage of each target battery 200 after synchronous correction and the target voltage of the target battery 200. It should be understood that the deviation degree of the voltage of each target battery 200 after synchronous correction relative to the target voltage of the target battery 200 can also be determined by other methods.

[0076] When the difference between the initial sampled voltage of each target battery 200 after synchronous correction and the target voltage of the target battery 200 is less than a preset voltage difference threshold (for example, 50mV) and the target voltage of the target battery 200 is within the optimal voltage range, it is determined that the initial sampled voltage of the target battery 200 after synchronous correction is within the optimal voltage range; the balancing unit 51 keeps sampling and monitoring the battery voltage.

[0077] like Fig.11As shown, when the difference between the voltage after synchronous correction of the initial sampling voltage of each target battery 200 and the target voltage of the target battery 200 is greater than or equal to the preset voltage difference threshold and the target voltage of the target battery 200 is in the optimal voltage interval, it is determined that the voltage after synchronous correction of the initial sampling voltage of the target battery 200 is not in the optimal voltage interval; it is necessary to detect whether the sampling time of the initial sampling voltage of the target battery 200 is within the preset balancing control time, wherein, when the sampling time of the initial sampling voltage of the target battery 200 is within the preset balancing control time, the current of the controllable discharge circuit 511 is set, and the current of the controllable discharge circuit 511 is adjusted based on the set current threshold of the controllable discharge circuit 511, and then the current of the target battery 200 is adjusted to adjust the voltage of the initial sampling voltage of the target battery 200 after synchronous correction to be close to the optimal voltage interval. In the process of adjusting the current of the controllable discharge circuit 511 based on the set value of the current of the controllable discharge circuit 511, the balancing unit 51 operates the controllable discharge circuit 511 through the micro control unit circuit 514 to adjust the current of the target battery 200. Detecting whether the sampling time of the initial sampling voltage of the target battery 200 is within the preset balancing control time can, to a certain extent, avoid the balancing unit 51 frequently operating the controllable discharge circuit 511 to cause additional loss.

[0078] The current of the controllable discharge circuit 511 has the following relationship:

[0079] in, I j represents the current of the controllable discharge circuit 511. When the voltage of the target battery 200 is stable, the current of the controllable discharge circuit 511 is substantially equal to the charging current provided by the DC power supply 10 to the target battery 200. I battery Subtract the battery's own leakage current; I jK The controllable discharge circuit 511 is represented by k A discharge current of a discharge switch 51131; K =1, 2, 3, ..., N ; V j represents the voltage of the target battery 200 after the initial sampling voltage is synchronously corrected; V up represents the upper limit of the optimal voltage range of the target battery 200; V C1 , V C2 , V C3 ，..., V CN are the 1st, 2nd, 3rd, ..., of the controllable discharge circuit 511 respectively. N A preset threshold voltage corresponding to each discharge switch 51131; V C1 , V C2 , V C3 ， ..., V CN The larger the difference between the voltage after synchronous correction of the initial sampled voltage of the target battery 200 and the target optimal voltage range, the larger the discharge current of the controllable discharge circuit 511 inside the equalization unit 51, so that the voltage after synchronous correction of the initial sampled voltage of the target battery 200 is finally close to the target optimal voltage.

[0080] In the process of performing balanced control on the voltage of the target battery 200, it is very important to monitor the voltage of the target battery 200. After setting the current of the controllable discharge circuit 511, the voltage stability of the target battery 200 can be detected.

[0081] The current of the controllable discharge circuit 511 is very small, generally 100mA, and the maximum value is no more than 500mA. Thus, under normal circumstances, the current and voltage of the target battery 200 change very slowly. When the current change of the target battery 200 is very small, for example, no more than 10%, the voltage change value of the target battery 200 is less than 50mV within a period of time, and it can be considered that the initial sampling voltage of the target battery 200 is V j Stablize.

[0082] According to Kirchhoff's law, I battery = I batteryj + I j ; I battery represents the charging current provided by the DC power supply 10 to the target battery 200; I batteryj Indicates j The actual float charge current of the target battery 200; I j represents the discharge current of the controllable discharge circuit 511; when the battery voltage of the target battery 200 is stable, it is considered that the DC power supply 10 provides a charging current of the target battery 200 I atteryj It is also stable, and it can be equivalent to the leakage current of the target battery 200.

[0083] Accordingly, in the process of detecting the voltage stability of the target battery 200, the first j The discharge current of the equalization unit 51 of each target battery 200 connected in parallel and the voltage of the target battery 200 after synchronous correction are sampled; when the change value of the voltage of the target battery 200 after synchronous correction within a continuous preset time is less than the preset voltage change threshold, it is determined that the voltage of the target battery 200 is stable, and the actual floating charge current of the target battery 200 is I batteryj and leakage current; or, when the voltage change ratio of the target battery 200 after synchronous correction within a continuous preset time is less than the preset voltage change threshold ratio value, the target battery 200 is determined to be stable in voltage. The preset time can be selected according to demand, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or other time ranges. The preset voltage change threshold can also be selected according to demand, for example, 50mV. When the voltage of the target battery 200 after synchronous correction is abnormal for a continuous preset time range, an alarm is issued, and the local alarm indicator light is on; and the alarm information is uploaded to the convergence unit 60.

[0084] In the process of balancing the voltage of the target battery 200, the initial sampled voltage of the target battery 200 after synchronous correction, the actual floating charge current of the target battery 200, the current of the controllable discharge circuit 511, and the sampled temperature can also be uploaded to the convergence unit 60.

[0085] According to the structure and working principle of the above-mentioned battery balancing control circuit, the present application proposes a control method of the battery balancing control circuit. Specifically, Fig.13 As shown, the control method of the battery balancing control circuit includes the steps of: S110, sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery 200 in the battery pack, and the current of each target battery 200 in the battery pack to obtain the sampled voltage of the battery pack, the sampled current of the battery pack, the initial sampled voltage of each target battery 200, and the sampled current of each target battery 200; S120, synchronously correcting the initial sampled voltages of all target batteries 200 in the battery pack, and determining whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries 200 is within a set normal range; wherein, by Calculate the voltage of each target battery 200 after synchronous correction of the initial sampled voltage; wherein, V k ( t nj ) indicates the k The target battery 200 jThe voltage after synchronous correction of the initial sampling voltage; V k ( t kj ) indicates the k Target battery 200 t kj The moment j The initial sampling voltage of the time; ω Indicates the correction coefficient of the sampling voltage based on time and sampling error, which is a preset value; t nj Indicates n Target battery 200 j The time of subsampling; t kj Indicates k Target battery 200 j The time of subsampling; n Indicates the number of all target batteries 200; S130, determine whether the voltage of each target battery 200 after synchronous correction of the initial sampling voltage is within the preset normal range of battery voltage; S140, balance control the voltage of the target battery 200.

[0086] In step S110, the voltage of the battery pack, the current of the battery pack, the voltage of each target battery 200 in the battery pack, and the current of each target battery 200 in the battery pack are sampled to obtain the sampled voltage of the battery pack, the sampled current of the battery pack, the initial sampled voltage of each target battery 200, and the sampled current of each target battery 200. Specifically, the current of the battery pack, the current of the target battery 200, and the voltage of the battery pack can be sampled by the sampling unit of the battery balancing control circuit to obtain the sampled current of the battery pack, the sampled voltage of the battery pack, and the sampled current of the target battery 200; and then the sampled current of the battery pack, the sampled voltage of the battery pack, and the sampled current of the target battery are transmitted to the convergence unit 60 of the battery balancing control circuit. The voltage of each target battery 200 can be sampled by the balancing unit 51 of the battery balancing control circuit to obtain the initial sampled voltage of each target battery 200; and then the initial sampled voltage of each target battery 200 is transmitted to the convergence unit 60 of the battery balancing control circuit.

[0087] In step S120, the initial sampled voltages of all target batteries 200 in the battery pack are synchronously corrected, and it is determined whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries 200 is within a set normal range. In the process of determining whether the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is within the set normal range, the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction are summed, and the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is compared with the normal value of the battery pack voltage; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction and the normal value of the battery pack voltage is less than a preset error threshold, the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is within the set normal range, and the state of the battery pack is healthy; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction and the normal value of the battery pack voltage is greater than or equal to the preset error threshold, it is determined that the sum of the voltages of the initial sampled voltages of all target batteries 200 after synchronous correction is not within the set normal range, the state of at least some of the target batteries 200 is unhealthy, and the state of the battery pack is unhealthy.

[0088] In one embodiment of the present application, the control method of the battery balancing control circuit determines whether the initial sampling voltage of each target battery 200 is credible before step S120; determining whether the initial sampling voltage of each target battery 200 is credible includes the steps of: S101, detecting whether the battery pack is in a floating charge state; S102, detecting whether the initial sampling voltage of each target battery 200 is stable and whether the sampling current of each target battery 200 is stable; S103, determining whether the difference between the sum of the initial sampling voltages of all target batteries 200 and the sampling voltage of the battery pack is less than a preset difference threshold.

[0089] In step S101, it is detected whether the battery pack is in a floating charge state. Specifically, when the battery pack is in a floating charge state, the sampling current of the battery pack is greater than 0, and the sampling current of the battery pack is equal to the charging current provided by the DC power supply 10 to the battery pack; and the current flowing through the battery pack is stable; the sampling current of the battery pack is less than the floating charge current of the battery pack; the sampling voltage of the battery pack is stable and consistent with the floating charge voltage. When the target battery 200 of the battery pack is not in a floating charge state, the sampling current of the battery pack and the sampling voltage of the battery pack are obtained again through the convergence unit 60. When it is determined that the battery pack is in a floating charge state, it is determined whether the initial sampling voltage and sampling current of each target battery 200 are stable.

[0090] When the initial sampling voltage or the sampling current of each target battery 200 is unstable, the sampling current and the sampling voltage of the battery group are obtained again through the convergence unit 60 .

[0091] When the target battery 200 of the battery pack is in a floating charge state and the voltage of the target battery 200 is stable, it is determined whether the difference between the sum of the initial sampled voltages of all the target batteries 200 and the sampled voltage of the battery pack is less than a preset difference threshold.

[0092] When the target battery 200 of the battery pack is in a floating charge state and the voltage of the target battery 200 is stable and the difference between the sum of the initial sampling voltages of all the target batteries 200 and the sampling voltage of the battery pack is less than the preset difference threshold, the initial sampling voltage of each target battery 200 is trusted, that is, the initial sampling voltage of each target battery 200 is determined to be credible. When the difference between the sum of the initial sampling voltages of all the target batteries 200 and the sampling voltage of the battery pack is not less than the preset difference threshold, the sampling current of the battery pack and the sampling voltage of the battery pack are obtained again through the convergence unit 60.

[0093] When the initial sampling voltage of the target battery 200 of the battery pack is abnormal, an alarm is generated. When the initial sampling voltage of the target battery 200 of the battery pack is normal, the sampling current and the sampling voltage of the battery pack are obtained again through the convergence unit 60 .

[0094] In step S130, it is determined whether the voltage of each target battery 200 after synchronous correction of the initial sampling voltage is within the preset normal range of battery voltage. k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage V k ( t nj ) is well below the voltage low threshold v low When, that is, When k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage is assigned to the j times before ( j -1) The average value of the initial sampled voltage of the target battery 200 after synchronous correction V pred , and control the count value of the sampling voltage alarm counter to add 1. When the count value of the sampling voltage alarm counter is greater than the preset number threshold N When k The voltage of the target battery 200 after synchronous correction of the initial sampling voltage is not within the preset normal range of battery voltage.k target batteries failed; among them, V kj Indicates the battery pack k The target battery 200 j The voltage after synchronous correction of the initial sampling voltage; V low Indicates the voltage low threshold; Indicates the voltage error threshold; ,in, V pred Indicates j times before ( j -1) times the average value of the initial sampled voltage of the target battery 200 after synchronous correction; V kM Indicates k The target battery 200 M The sampling voltage is the voltage after synchronous correction.

[0095] In step S140, the voltage of the target battery 200 is balanced and controlled. Specifically, based on the difference between the voltage of the initial sampled voltage of each target battery 200 after synchronous correction and the target voltage of the target battery 200, it is determined whether the voltage of the initial sampled voltage of the target battery 200 after synchronous correction is in the optimal voltage range. When the difference between the voltage of the initial sampled voltage of each target battery 200 after synchronous correction and the target voltage of the target battery 200 is less than a preset voltage difference threshold (for example, 50mV) and the target voltage of the target battery 200 is in the optimal voltage range, it is determined that the voltage of the initial sampled voltage of the target battery 200 after synchronous correction is in the optimal voltage range; the balancing unit 51 keeps sampling and monitoring the battery voltage. When the difference between the voltage after synchronous correction of the initial sampled voltage of each target battery 200 and the target voltage of the target battery 200 is greater than or equal to the preset voltage difference threshold and the target voltage of the target battery 200 is in the optimal voltage range, it is determined that the voltage after synchronous correction of the initial sampled voltage of the target battery 200 is not in the optimal voltage range, and it is detected whether the sampling time of the initial sampled voltage of the target battery 200 is within the preset balancing control time, wherein when the sampling time of the initial sampled voltage of the target battery 200 is within the preset balancing control time, the voltage of the target battery 200 is adjusted by the balancing unit 51.

[0096] In the process of adjusting the voltage of the target battery 200 through the equalization unit 51, the current of the controllable discharge circuit 511 is adjusted, and then the charging current of the target battery 200 is adjusted, so that the voltage of the initial sampling voltage of the target battery 200 after synchronous correction is adjusted to be close to the optimal voltage range. In the process of adjusting the current of the controllable discharge circuit 511, the micro control unit circuit 514 operates the controllable discharge circuit 511 to adjust the current of the controllable discharge circuit 511, and then the charging current of the target battery 200 is adjusted.

[0097] In the process of balancing the voltage of the target battery 200, the voltage stability of the target battery 200 can also be detected. Specifically, when the change value of the voltage after the synchronous correction of the initial sampled voltage of the target battery 200 is less than the preset voltage change threshold value within a continuous preset time, the voltage of the target battery 200 is determined to be stable; or, when the change ratio of the voltage after the synchronous correction of the initial sampled voltage of the target battery 200 is less than the preset voltage change threshold ratio value within a continuous preset time, the voltage of the target battery 200 is determined to be stable. When the voltage after the synchronous correction of the initial sampled voltage of the target battery 200 is abnormal within a preset time range, an alarm is issued, and the local alarm indicator light is on; and the alarm information is uploaded to the convergence unit 60.

[0098] In the process of balancing the voltage of the target battery 200, the initial sampled voltage of the target battery 200 after synchronous correction, the actual floating charge current of the target battery 200, the current of the controllable discharge circuit 511, and the sampled temperature can also be uploaded to the convergence unit 60.

[0099] In summary, the control method of the battery balancing control circuit according to the embodiment of the present application is explained, and the control method of the battery balancing control circuit enables the voltage of each target battery 200 to be reliably sampled and balanced, thereby extending the life of the battery pack.

[0100] The present application and its implementation methods are described above, and such description is not restrictive. The drawings show only one implementation method of the present application, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design structural methods and embodiments similar to the technical solution without creative design without departing from the inventive purpose of the present application, they should all fall within the protection scope of the present application.

Claims

1. A control method for a battery balancing control circuit, wherein: The method for controlling the voltage of a target battery of a battery pack comprises the steps of: Sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery in the battery pack, and the current of each target battery in the battery pack to obtain a sampled voltage of the battery pack, a sampled current of the battery pack, an initial sampled voltage of each target battery, and a sampled current of each target battery; Synchronously correct the initial sampled voltages of all target batteries in the battery pack, and determine whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is within a set normal range; wherein, Calculate the voltage of each target battery after the initial sampling voltage is synchronously corrected; where, V k ( t nj ) indicates the k The target battery j The voltage after synchronous correction of the initial sampling voltage; V k ( t kj ) indicates the k The target battery t kj The moment j The initial sampling voltage of the time; ω Indicates the correction coefficient of the sampling voltage based on time and sampling error, which is a preset value; t nj Indicates n Target battery No. j The time of subsampling; t kj Indicates k Target battery No. j The time of subsampling; n Indicates the number of all target batteries; Determine whether the voltage of each target battery after synchronous correction of the initial sampled voltage is within a preset normal range of battery voltage; and The voltage of the target battery is balanced and controlled.

2. The control method of the battery balancing control circuit according to claim 1, characterized in that: In the process of sampling the voltage of the battery pack, the current of the battery pack, the voltage of each target battery in the battery pack, and the current of each target battery in the battery pack, the current of the battery pack, the voltage of the battery pack, and the current of the target battery are sampled by the sampling unit of the battery balancing control circuit to obtain the sampled current of the battery pack, the sampled voltage of the battery pack, and the sampled current of the target battery; the voltage of each target battery is sampled by the balancing unit of the battery balancing control circuit to obtain the initial sampling voltage of each target battery.

3. The control method of the battery balancing control circuit according to claim 1, characterized in that: In the process of synchronously correcting the initial sampled voltages of all target batteries in the battery pack and determining whether the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is within a set normal range, when the difference between the sum of the voltages of the initial sampled voltages of all target batteries after the synchronous correction and the normal value of the battery pack voltage is less than a preset error threshold, the sum of the voltages of the initial sampled voltages of all target batteries after the synchronous correction is within the set normal range; when the difference between the sum of the voltages of the initial sampled voltages of all target batteries after the synchronous correction and the normal value of the battery pack voltage is greater than or equal to the preset error threshold, it is determined that the sum of the voltages obtained after the synchronous correction of the initial sampled voltages of all target batteries is not within the set normal range.

4. The control method of the battery balancing control circuit according to claim 1, characterized in that: In the process of determining whether the voltage of each target battery after synchronous correction of the initial sampled voltage is within the preset normal range of battery voltage, When k The target battery j The voltage after synchronous correction of the initial sampling voltage is assigned to the j times before ( j -1) times of the target battery's initial sampled voltage after synchronous correction, and control the count value of the sampled voltage alarm counter to add 1. When the count value of the sampled voltage alarm counter is greater than the preset number threshold N When k target batteries failed; among them, V kj Indicates the battery pack k The target battery j The voltage after synchronous correction of the initial sampling voltage; V low Indicates the voltage low threshold; Indicates the voltage error threshold; ,in, V pred Indicates j times before ( j -1) times the average voltage of the initial sampled voltage of the target battery after synchronous correction; V kM Indicates k The target battery M The sampling voltage of the time.

5. The control method of the battery balancing control circuit according to claim 1, characterized in that: The control method of the battery balancing control circuit also includes the steps of: detecting whether the battery pack is in a floating charge state; detecting whether the initial sampling voltage of each target battery is stable and whether the sampling current of each target battery is stable; and determining whether the difference between the sum of the initial sampling voltages of all target batteries and the sampling voltage of the battery pack is less than a preset difference threshold.

6. The control method of the battery balancing control circuit according to claim 1, characterized in that: During the voltage balancing control of the target battery, it is determined whether the synchronously corrected initial sampled voltage of the target battery is within the optimal voltage range based on the difference between the synchronously corrected initial sampled voltage of each target battery and the target voltage of the target battery.

7. The control method of the battery balancing control circuit according to claim 6, characterized in that: When the difference between the synchronously corrected voltage of the initial sampled voltage of each target battery and the target voltage of the target battery is less than the preset voltage difference threshold and the target voltage of the target battery is in the optimal voltage range, it is determined that the synchronously corrected voltage of the initial sampled voltage of the target battery is in the optimal voltage range; When the difference between the voltage after synchronous correction of the initial sampled voltage of each target battery and the target voltage of the target battery is greater than or equal to the preset voltage difference threshold and the target voltage of the target battery is in the optimal voltage range, it is determined that the voltage after synchronous correction of the initial sampled voltage of the target battery is not in the optimal voltage range, and it is detected whether the sampling time of the initial sampled voltage of the target battery is within the preset balancing control time.

8. The control method of the battery balancing control circuit according to claim 7, characterized in that: When the synchronously corrected sampled voltage of the target battery is not within the optimal voltage range and the sampling time of the initial sampled voltage of the target battery is within the preset balancing control time, the voltage of the target battery is adjusted by the balancing unit of the battery balancing control circuit.

9. The control method of the battery balancing control circuit according to claim 8, characterized in that: In the process of adjusting the voltage of the target battery through the balancing unit of the battery balancing control circuit, the current of the controllable discharge circuit of the balancing unit is adjusted, and then the charging current of the target battery is adjusted to adjust the voltage of the initial sampling voltage of the target battery after synchronous correction to be close to the optimal voltage range.

10. The control method of the battery balancing control circuit according to claim 9, characterized in that: The control method of the battery balancing control circuit also includes the steps of uploading the voltage of the initial sampled voltage of the target battery after synchronous correction, the actual floating charge current of the target battery, the current of the controllable discharge circuit, and the sampled temperature to the convergence unit.

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