WO2019042356A1

WO2019042356A1 - Battery equalization method and system, vehicle, storage medium, and electronic device

Info

Publication number: WO2019042356A1
Application number: PCT/CN2018/103251
Authority: WO
Inventors: 罗红斌; 王超; 沈晓峰; 曾求勇; 刘苑红; 张祥
Original assignee: 比亚迪股份有限公司
Priority date: 2017-08-31
Filing date: 2018-08-30
Publication date: 2019-03-07
Also published as: CN109435771A; CN109435771B

Abstract

A battery equalization method and system, a vehicle, a storage medium, and an electronic device. The battery equalization method comprises: obtaining SOC values of cells to be equalized in a battery pack (S51); obtaining reference SOC values required for equalization (S52); according to the SOC values of the cells to be equalized, the reference SOC values, and a preset equalization duty cycle, determining a target equalization duration of the cells to be equalized, wherein the equalization duty cycle is a ratio of an equalization period within a unit cycle to the unit cycle, the unit cycle comprising the equalization period and a sampling period (S53); and according to the target equalization duration, controlling, within the equalization period of the unit cycle, the equalization of the cells to be equalized (S54).

Description

Battery balancing method, system, vehicle, storage medium, and electronic device

Cross-reference to related applications

The present application claims the priority of the Chinese patent application No. "201710775017.8", which was filed on August 31, 2017, by the BYD Co., Ltd., entitled "Battery equalization method, system, vehicle, storage medium and electronic device".

Technical field

The present disclosure relates to the field of control technologies, and in particular, to a battery equalization method, system, vehicle, storage medium, and electronic device.

Background technique

Large-capacity batteries that provide power for electric vehicles are often referred to as power batteries. A vehicle power battery generally consists of a plurality of single cells connected in series to form a module. With the use of the battery, the difference between the individual cells gradually expands, and the consistency between the cells is poor. Due to the short board effect of the battery, the capacity of the battery pack is limited, so that the capacity of the battery pack cannot be fully exerted, resulting in the battery pack. The overall capacity is reduced. On the other hand, the gradual enlargement of the differences between the individual cells will cause over-charging of some single cells, over-discharge of some single cells, affecting battery life, damaging the battery, and possibly generating a large amount of heat to cause the battery. Burning or exploding.

Therefore, effective balancing management of the electric vehicle power battery is beneficial to improve the consistency of each battery in the power battery pack, reduce the battery capacity loss, extend the service life of the battery and the driving range of the electric vehicle, and is of great significance.

The current battery equalization method may also collect battery information while also performing equalization. Since the equalization process may cause fluctuations in battery information, this may result in inaccurate collection of battery information, which may result in equalization of cells in a single cell. When the calculated equalization time is inaccurate, the equalization effect is poor.

Summary of the invention

The purpose of the present disclosure is to provide a battery equalization method, system, vehicle, storage medium and electronic device, which can separately perform sampling and equalization in a unit cycle, ensuring the accuracy of the collected battery information, and calculating the equilibrium. The duration is more accurate, and it also improves the balance of the battery pack.

In order to achieve the above object, in a first aspect, the present disclosure provides a battery equalization method, the method comprising:

Obtaining an SOC value of the battery to be equalized in the battery pack;

Obtain the reference SOC value required for equalization;

Determining, according to the SOC value of the to-be-equalized unit cell, the reference SOC value, and a preset equalization duty ratio, a target equalization period of the to-be-equalized unit cell, wherein the equalization duty ratio is a unit period a ratio of the equalization period within the unit period to the unit period, the unit period including the equalization period and the sampling period;

According to the target equalization duration, the equalization of the cells to be equalized is controlled during the equalization period of the unit period.

In a second aspect, the present disclosure provides a battery equalization system, where the system includes: an equalization module, an acquisition module, and a control module;

The collecting module is configured to collect battery information of a battery pack, and the battery information is used to determine an SOC value of each single battery in the battery pack;

The control module is configured to acquire an SOC value of the unit cell to be equalized in the battery group; obtain a reference SOC value required for equalization; and according to the SOC value of the unit battery to be equalized, the reference SOC value, and a pre- Determining a duty ratio of the target equalization time of the unit to be equalized, wherein the equalization duty ratio is a ratio of the equalization period to the unit period; and, according to the target equalization period, Controlling the equalization of the cells to be equalized during the equalization period of the unit period;

The equalization module is configured to equalize the to-equalize cells under the control of the control module.

In a third aspect, the present disclosure provides a vehicle comprising the battery equalization system of the above second aspect.

In a fourth aspect, the present disclosure provides a computer readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the method of the first aspect described above.

In a fifth aspect, the present disclosure provides an electronic device, including:

a computer readable storage medium according to the fourth aspect;

One or more processors for executing a computer program in the computer readable storage medium.

Through the above technical solution, the collection and equalization of the battery information are performed in a time-division manner in a unit period, so as to avoid the influence of the equalization current on the accuracy of the battery information collection when the battery information collection and equalization are simultaneously performed; on the other hand, the equalization duty ratio can be It reflects the proportion of the equalization period and the adoption period in the unit duration. Therefore, the target equalization period calculated in consideration of the equilibrium duty ratio can better balance the cells that need to be balanced, and also provides a kind of A new way to determine the target's equilibrium duration.

Other features and advantages of the present disclosure will be described in detail in the detailed description which follows.

DRAWINGS

The drawings are intended to provide a further understanding of the disclosure, and are in the In the drawing:

1 is a schematic diagram of a battery equalization system according to an embodiment of the present disclosure;

2 is a schematic diagram of a battery equalization system in which two single cells share an equalization module according to an embodiment of the present disclosure;

3 is a schematic diagram of a battery equalization system according to another embodiment of the present disclosure;

4 is a schematic diagram of a battery equalization system in which two single cells share one equalization module according to another embodiment of the present disclosure;

FIG. 5 is a schematic flow chart of a battery equalization method according to an embodiment of the present disclosure; FIG.

6 is an open circuit voltage OCV-remaining power SOC curve of a single cell according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram of an equalization module according to an embodiment of the present disclosure.

Detailed ways

The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are not to be construed

1 is a schematic diagram of a battery equalization system according to an embodiment of the present disclosure. The battery equalization system includes a control module 101, an acquisition module 102, and an equalization module 103. The battery equalization system can be used to equalize the battery pack 104.

In one embodiment, each unit cell corresponds to one acquisition module 102 and one equalization module 103. The acquisition module 102 and the equalization module 103 corresponding to the same single cell are respectively connected to the control module 101 through different control channels. The control module may include a control chip, and the control chip is respectively connected to the acquisition module and the equalization module corresponding to the same single cell through two pins, and the two pins are in one-to-one correspondence with the two channels.

In this embodiment, the control module 101 controls the collection module 102 and the equalization module 103 to be turned on and off according to the unit cycle, respectively, to collect battery information and equalize the battery, so that battery information collection and equalization are performed in a time-sharing manner. Avoid the impact of equalizing current on the accuracy of battery information collection when battery information acquisition and equalization are performed simultaneously.

In one embodiment, as shown in FIG. 1, each of the cells in the battery is coupled to an acquisition module 102 and an equalization module 103, respectively. If the battery pack includes N single cells, there are N acquisition modules 102 and N equalization modules 103. Thus, the control module 101 passes through 2×N control channels, respectively, with N acquisition modules and N equalization modules. connection.

The control channel or channel refers to a transmission path of a control command of the control module to the execution end (acquisition module and equalization module).

In other embodiments, different single cells may share an equalization module, for example, N single cells in a battery pack, may share the same equalization module, or each preset number (eg, 2, 3, or 5 equal) single cells share an equalization module and the like. When at least two of the multi-cell cells sharing one equalization module need to be equalized, the equalization module and each of the at least two single cells that need to be equalized are equalized during the equalization period of the unit period. The batteries are connected alternately.

Referring to FIG. 2, two single cells share an equalization module. When two cells of a single equalization module need to be equalized, the equalization module is alternately connected with each cell during an equalization period of a unit cycle. Alternate connections may be alternate connections at a certain period. For example, referring to FIG. 2, when the parallel switch 150 on the parallel branch 15 corresponding to one of the two single cells 111 is closed for 2 s under the control of the control module 14, the other of the two cells The parallel switch 150 on the parallel branch 15 corresponding to the unit cell 111 is disconnected for 2 s under the control of the control module 14. That is, the parallel switch 150 on the parallel branch 15 corresponding to each of the two single cells, in the equalization period, switches from the closed state to the open state every two seconds, or from the disconnected state. Switch to the closed state. Therefore, on the basis of the time-division of the acquisition module and the equalization module, during the equalization period, the single cells sharing the same equalization module are alternately connected with the shared equalization module to achieve equalization.

3 is a schematic structural diagram of a battery equalization system according to another embodiment of the present disclosure.

The battery equalization system includes a control module 301, an acquisition module 302, and an equalization module 303, which can be used to equalize the battery pack 304. Wherein, the battery pack 304 includes a plurality of unit cells connected in series. The control module 301 is connected to the acquisition module 302 and the equalization module 303 corresponding to the same single cell through a control channel 305. The control module 301 is configured to control and control when it is determined that the single battery connected to the control module 301 does not need to be equalized. The module 301 is connected to the corresponding sampling module 302. Alternatively, the control module 301 is further configured to: when determining that the single battery connected to the control module 301 needs to be equalized, the collecting module 302 and the equalizing module 303 divide the channel according to the unit period. 305.

One unit period includes: an acquisition period and an equalization period. The control module 301 controls the acquisition module 302 to sample the battery information of the single battery during the collection period to obtain the battery information of the single battery. The battery information includes at least one of the following: voltage, current, temperature, and the like. In one embodiment, the battery information may include only voltage values, whereby voltage performance parameters of the single battery may be obtained. In another embodiment, the battery information may also include a voltage value, a current value, a temperature value, and the like, thereby obtaining a SOC (State of Charge), an internal resistance, a self-discharge rate, and the like of the single battery. parameter.

The control module 301 determines, according to the battery information of the single battery collected by the collection module 302, the cell to be equalized that needs to be balanced. The control module 301 controls an equalization module corresponding to the to-be-equalized unit cell to balance the cells to be equalized during the equalization period.

Therefore, in the embodiment of the present disclosure, the acquisition module and the equalization module share the same control channel, and the control module controls the acquisition module and the equalization module, and the control channel is time-multiplexed according to the unit period, thereby avoiding battery information collection and equalization. In the process of performing, the influence of the equalization current on the accuracy of the battery information collection; on the other hand, compared with the embodiment shown in FIG. 1 above, the number of channels of the control module chip is reduced, and the hardware cost can be saved.

In one embodiment, a switch K is provided in the control channel shared by the acquisition module and the equalization module. The control module 301 is connected to the switch K, and the time-sharing is connected to the acquisition module 302 or the equalization module 303 by controlling the switch K. When the switch K is connected to the acquisition module 302, the control module 301 controls the acquisition module 302 to collect battery information for the single battery during the collection cycle. When the switch K is connected to the equalization module 303, the control module 301 controls the equalization module 303. The corresponding single cells are equalized.

In one embodiment, as shown in FIG. 3, each of the cells in the battery is connected to an acquisition module 302 and an equalization module 303, respectively. If the battery pack includes N single cells, the number of the acquisition modules 302 is N, and the equalization module 303 is N. Thus, the control module 301 is connected to the acquisition module and the equalization module through N control channels.

Referring to FIG. 4, an exemplary schematic diagram of sharing an equalization module for two single cells is shown. When two cell units sharing one equalization module need to be equalized, the equalization module is alternately connected with each unit cell during the equalization period of the unit period. Alternate connections may be alternate connections at a certain period. Therefore, on the basis of the time-division of the acquisition module and the equalization module, during the equalization period, the single cells sharing the same equalization module are alternately connected with the shared equalization module to achieve equalization.

In one embodiment, the acquisition module can be a voltage acquisition chip for collecting the voltage of the single battery during the acquisition period.

Referring to FIG. 5, based on the battery equalization system shown in any of the foregoing embodiments of FIG. 1, FIG. 2, FIG. 3 or FIG. 4, the battery equalization method according to an embodiment of the present disclosure includes:

In step S51, the SOC value of the unit cell to be equalized in the battery pack is acquired.

In step S52, the reference SOC value required for equalization is obtained.

In step S53, determining a target equalization time period of the unit cells to be equalized according to the SOC value of the unit cells to be equalized, the reference SOC value, and a preset equalization duty ratio, wherein the equalization duty ratio is an equalization in a unit period. The ratio of the time period to the unit period, and the unit period includes the equalization period and the sampling period.

In step S54, the equalization of the cells to be equalized is controlled in the equalization period of the unit period in accordance with the target equalization period.

The sampling module can collect battery information of each single battery in the battery pack (including, for example, a voltage value, a current value, a temperature value, and the like), and the control module can calculate the SOC value according to the battery information collected by the sampling module.

For any single cell in the battery pack, the SOC value of the single cell can be calculated by using the ampere integration method or the ampere integration method in combination with the voltage correction method.

The ampere-hour integral method refers to the SOC value of the single-cell battery obtained by integrating the current value of the collected single-cell battery with time; the ampere-hour integration method combined with the voltage correction method first calculates the SOC of the single-cell battery by using the chrono integration method. The value is then corrected using the load voltage value of the single cell to the calculated SOC value, and the corrected SOC value is taken as the final SOC value of the single cell.

The voltage value of the single cell collected during the sampling period of the unit period is the load voltage value of the single cell, that is, the voltage value during charging or discharging of the single cell. According to the correspondence relationship between the load voltage value of the single cell and the OCV value, that is, the OCV value=the load voltage value+the internal resistance value of the single cell×the charging current value or the discharge current value of the single cell, the single cell can be obtained. OCV value.

Since each single cell corresponds to an OCV-SOC curve, as shown in Fig. 6, in the interval [0, SOC1] and the interval [SOC2, 1], the OCV value varies greatly, so the ampere-time integration method is adopted. The SOC value obtained by the voltage correction method is more accurate; within the interval (SOC1, SOC2), the variation of the OCV value is small. If the ampere-hour integration method combined with the voltage correction method is used in this interval, the single-cell battery may not be accurately obtained. The SOC value, which in turn leads to the inability to accurately determine the cell to be equalized, is therefore more accurate with the SOC value obtained by the ampere-time integration method.

Optionally, in order to accurately calculate the SOC value of any single battery, in one embodiment, the value range of the SOC value is divided into an end value of 0 and a first SOC value according to an OCV-SOC curve of the corresponding single battery. The first interval of the first interval (the SOC1 in FIG. 6), the second value of the first SOC value and the second SOC value (such as SOC2 in FIG. 6), and the end value is the second SOC value and the first 100% The third interval, the method for calculating the SOC value includes a first calculation manner and a second calculation manner, wherein the first calculation manner corresponds to the first interval and the third interval, and the second calculation manner corresponds to the second interval. Correspondingly, the above step S51 includes the following steps:

For any single battery in the battery pack, the control module determines the SOC value of the single battery according to the first calculation manner.

When the SOC value determined according to the first calculation manner belongs to the second interval, the control module re-determines the SOC value of the single battery according to the second calculation manner.

Optionally, the first calculation method is an ampere-hour integration method or an ampere-hour integration method combined with a voltage correction method, and the second calculation method is an ampere-hour integration method and an ampere-hour integration method combined with a voltage correction method that is different from the first calculation method. the way.

In the embodiment of the present disclosure, since the first interval and the third interval have a large rate of voltage change, the SOC value of the battery can be calculated by adjusting the real-time voltage of the battery (in this case, the load voltage). Because the rate of change of the battery voltage is small in the second interval, the accuracy of calculating the SOC value by introducing the voltage variable is not high, so the SOC value can be directly calculated by the ampere-time integration method. In this way, it is possible to further determine how to obtain the SOC value of the single cell for the difference in the SOC value interval of the single cell, so that the obtained SOC value of the single cell is relatively accurate, thereby making the determined need Balanced single cells are also more accurate.

In another embodiment, when the battery is just working, the battery SOC value can also be calculated by using an open circuit voltage method, that is, the voltage value of the battery is collected (the equivalent is an open circuit voltage value), and the OCV-SOC correspondence can be checked. Calculate the battery SOC value.

Optionally, the first calculation manner is a calculation method used by the single battery to calculate the SOC value.

For any single cell in the battery pack, the SOC value of the single cell can be calculated first by using any one of the hourly integration method and the ampere-hour integration method combined with the voltage correction method. For the first calculation method. Next, the first calculation method is an ampere-time integration method and the first calculation method is an ampere-hour integration combined with a voltage correction method.

Case 1: The first calculation method is the ampere-hour integration method. Correspondingly, the second calculation method is the ampere-hour integration combined with the voltage correction method.

In response to this, first, based on the ampere-time integration method, the SOC value of the unit cell is obtained based on the collected battery information (such as a current value) of the unit cell, and the section to which the calculated SOC value belongs is determined. If the calculated SOC value belongs to the first interval or the third interval, since the results obtained by using the ampere-hour integral combined with the voltage correction method in the first interval and the third interval are more accurate, the ampere-hour integral combined with the voltage correction method is used to determine The SOC value of the single battery, and the ampere-hour integration combined with the voltage correction method as the first calculation method, that is, the next calculation of the SOC value of the single battery is first calculated by using the ampere-hour integral combined with the voltage correction method; The SOC value belongs to the second interval. Since the result obtained by using the ampere-time integral method in the second interval is more accurate, there is no need to recalculate, and the chrono integration method can be used as the first calculation method, that is, the next calculation of the single cell The SOC value is first calculated using the ampere-time integral method.

Case 2: The first calculation method is an ampere-hour integral combined with a voltage correction method, and correspondingly, the second calculation method is an ampere-time integration method.

For this situation, firstly, based on the integration time and voltage correction method, the SOC value of the single battery is obtained according to the collected battery information (such as the load voltage value), and the interval to which the calculated SOC value belongs is determined. . If the calculated SOC value belongs to the first interval or the third interval, since the results obtained by using the ampere-hour integral combined with the voltage correction method in the first interval and the third interval are more accurate, the calculation may be performed without re-calculation. Combined with the voltage correction method as the first calculation method, the next calculation of the SOC value of the single cell is first calculated by using the ampere-hour integral combined with the voltage correction method; if the calculated SOC value belongs to the second interval, it is adopted in the second interval. The result obtained by the ampere-time integral method is more accurate, and the SOC value of the single battery is re-determined by the ampere-hour integration method, and the ampere-hour integration method can be used as the first calculation method, that is, when the SOC value of the single-cell battery is calculated next time. First, it is calculated by the ampere-time integral method.

After the control module determines the SOC value of each single battery in the battery pack, the reference SOC value may be determined, and the SOC value of any one of the battery cells may be used as a reference SOC value, for example, the second section in the battery pack The SOC value of the body battery is taken as a reference SOC value; or, the reference SOC value may be determined according to the SOC value of each unit cell. For example, any one of the minimum SOC value, the maximum SOC value, the average value, and the like among the SOC values of the individual cells in the battery pack may be determined as the reference SOC value.

The unit cell to be equalized may be a unit cell in the battery pack determined by some performance parameters of the battery, and the performance parameters for determining the unit cell to be equalized may include, for example, voltage value, SOC, internal resistance, self-discharge. Rate, voltage change rate, power rate change rate, time change rate, and so on.

Please refer to Table 1 below. Table 1 exemplifies the parameters used to determine the cell to be equalized as voltage value, SOC, internal resistance, self-discharge rate, voltage change rate, power change rate or time change rate. The manner in which the cell to be equalized is to be balanced is determined in the battery pack, and after determining the cell to be equalized, the corresponding cell to be equalized is subsequently balanced.

Among them, the self-discharge rate of the single cell is used to characterize the capacity loss and capacity loss rate of the single cell. In one embodiment, when the battery pack stops working and reaches a steady state (at time t1), the open circuit voltage value V1 of each unit battery of the power battery pack is detected and recorded; when the battery pack starts to start again (t2 time) Detecting and recording the open circuit voltage value V2 of each single cell of the power battery pack; calculating the self-discharge rate η of each single cell and calculating the self-discharge rate value η according to the open circuit voltage values of the individual cells obtained by the two tests The method is:

(1) Based on the OCV-SOC curve of the battery (such as the curve shown in FIG. 6), the SOC value corresponding to V1 and the SOC value corresponding to V2 are found according to the detected V1 and V2;

(2) calculating the SOC change value ΔSOC of the battery according to the two SOC values respectively corresponding to V1 and V2;

(3) Calculate the battery capacity discharged from the battery self-discharge according to ΔSOC and the battery full capacity C, ΔQ=ΔSOC*C;

(4) Calculate the value of the self-discharge rate η of the battery: η = ΔQ / (t1 - t2).

The voltage change rate of the unit cell may be a voltage change amount when the unit of the specified physical quantity of the unit cell is changed. For example, in the present disclosure, a predetermined amount of electric power is charged or discharged to a single battery, a voltage variation amount (dv/dq) of the single battery, or a preset time for charging or discharging the single battery, and a voltage change of the single battery. The amount (dv/dt) is taken as an example for explanation.

The rate of change in the amount of electricity of the unit cell may be the amount of change in the amount of electricity when the unit of the specified physical quantity of the unit cell changes. For example, in the present disclosure, the amount of charge (dq/dv) required to increase the voltage of the unit cell by one unit voltage from the initial voltage, or the amount of decrease in the unit voltage by one unit voltage from the initial voltage (dq/) Dv) is explained as an example.

The time change rate of the unit cell may be the amount of time change when the unit of the specified physical quantity of the unit cell changes. For example, in the present disclosure, the charging time (dt/dv) required for the voltage of the single cell to rise by one unit voltage from the initial voltage, or the discharge time required for the voltage of the single cell to drop by one unit voltage from the initial voltage (dt/) Dv) is explained as an example.

Table 1

In the embodiment of the present disclosure, the reference SOC value used to calculate the target equalization time of the unit cells to be equalized may be a minimum value of the SOC values of the individual cells, a maximum value of each of the cell voltages, or a single The average of the SOC values of the body batteries.

The equalization duty ratio is a ratio of the equalization period in the unit period to the unit period, and can be used to represent the proportion of the equalization period and the sampling period in the unit period. The preset equalization duty ratio may be preset, and the equalization duty ratio is constant during the equalization process, for example, set to 50%, and the like.

Optionally, after determining the SOC value of the cell to be equalized, the target equalization time period for equalizing the cell to be equalized under the set equalization duty ratio may be calculated. Hereinafter, a description will be given of a manner in which it is possible to determine the target equalization time length of the unit cells to be equalized, depending on the SOC value of the unit cells to be equalized and the reference SOC value.

The first way:

First, the power difference is determined according to ΔQ=ΔSOC×C _n , where ΔQ is the power difference, ΔSOC is the SOC difference between the SOC value of the cell to be equalized and the reference SOC value, and C _n is the cell to be equalized Available capacity

Then, the target equalization duration is determined according to t = ΔQ / (I × τ), where t is the target equalization duration, I is the equalization current of the unit cell to be equalized, and τ is the preset equalization duty.

The second way:

Determining, according to a preset correspondence between the SOC difference between the SOC value of the unit cell to be equalized and the reference SOC value, the equalization duty ratio, and the SOC difference value, the equalization duty ratio, and the target equalization time length. The target equalization time of the cell to be balanced.

The correspondence between the preset SOC difference, the equalization duty ratio and the equalization duration can be obtained by multiple equalization tests or experience, such as by means of a table, so that the measured SOC difference can be found in the table. And the value of the corresponding target equalization time period under the preset equalization duty ratio.

After obtaining the target equalization duration, the equalized cells can be equalized according to the target equalization duration in the equalization period of the unit period. The manner of equalization may be different depending on the difference in the reference SOC value used to calculate the equalization duration.

Optionally, if the reference SOC value is the minimum value of the SOC values of the single cells, the battery cells to be equalized are controlled to be discharged during the equalization period of the unit cycle; or, if the reference SOC value is the SOC value of each of the single cells The maximum value of the cell to be equalized is controlled during the equalization period of the unit period; or, if the reference SOC value is the average value of the SOC values of the individual cells, the SOC value of the cell to be equalized is greater than the reference SOC value At the time of the equalization period of the unit period, the battery cells to be equalized are controlled to be discharged, and when the SOC value of the unit to be equalized is less than the reference SOC value, the battery to be equalized is controlled to be equalized during the equalization period of the unit period.

The following embodiments focus on the equalization process related embodiments: Referring to FIG. 7, a schematic diagram of an equalization module according to an embodiment of the present disclosure. The equalization of the unit cells to be equalized in the equalization period of the unit period is performed in conjunction with the above-described equalization judgment. According to the step of equalization judgment, it is determined that the equalization mode of the cells to be equalized is passive equalization (ie, discharging the cell to be equalized), or is actively equalized (that is, charging the cell to be equalized), and the corresponding equalization is turned on. Module.

Referring to FIG. 7, for passive equalization, the equalization module includes: a resistor 811, each of which corresponds to an equalization module, that is, a resistor is connected in parallel with each end of each unit cell.

For a cell to be balanced that needs to be passively equalized, during an equalization period of a unit period, the control module controls parallel circuit conduction between the cell to be equalized and its corresponding resistor to perform passive operation on the cell balanced. Referring to FIG. 7, the control module is turned on by controlling the switch module 812 to realize conduction of a parallel circuit between the cell to be equalized and its corresponding resistor.

The resistor 811 can be a fixed value resistor or a variable resistor. In one embodiment, the resistor 811 can be a positive temperature coefficient thermistor, which can change with temperature, thereby adjusting the equalization current generated during equalization, thereby automatically adjusting the heat generation of the battery equalization system, and finally The temperature of the battery equalization system is effectively controlled.

Referring to FIG. 7, for active equalization, the equalization module includes a charging branch 94 connected in parallel with each of the unit cells 95 in the battery pack. The charging branch 94 is in one-to-one correspondence with the unit cells 95, and each charging branch 94 is provided. Both are coupled to a generator 92 that is mechanically coupled to the engine 91 via a gear.

For the unit cell to be balanced that needs to be actively equalized, the control module controls the charging branch 94 corresponding to the unit cell to be equalized to be turned on. When the engine 91 rotates, the generator 92 is driven to generate electricity, so that the electric power generated by the generator 92 is supplied to the unit cells to be equalized, so that the electric quantity of the unit to be equalized is increased.

Referring to FIG. 7, when the generator 92 is an alternator, the equalization module further includes a rectifier 93 in series with the generator 92, each of the charging branches 130 being connected in series with the rectifier 132. After the alternating current generated by the generator 92 is converted to direct current by the rectifier 93, the generator 92 can be enabled to charge the individual cells to be equalized.

Referring to FIG. 7, the control module can be turned on by controlling the switch 96 corresponding to the cell to be balanced, so that the charging branch corresponding to the cell to be balanced is turned on, and the active equalization of the cell to be equalized is performed.

In other embodiments, in addition to charging the unit cells with a generator as shown in FIG. 7, the unit cells to be equalized can also be charged by the starter battery in the vehicle.

In another embodiment, in addition to the parallel resistor and the unit battery to be balanced, as shown in FIG. 7, the unit cell to be equalized can be connected in parallel with the starting battery of the vehicle, and the battery to be balanced can be charged. The battery is activated to achieve equalization of the cells to be balanced while effectively avoiding waste of energy.

As described above, in the embodiment of the present disclosure, a plurality of single cells may share one equalization module, and when at least two of the multi-cell cells sharing one equalization module need to be equalized, in a unit period During the equalization period, the equalization module is alternately connected with each of the at least two single cells that need to be equalized, and is separately equalized.

Accordingly, embodiments of the present disclosure also provide a vehicle including the battery equalization system described above.

Correspondingly, an embodiment of the present disclosure further provides a computer readable storage medium having stored thereon computer program instructions, the computer program instructions being implemented by a processor to implement the battery equalization method described above.

Correspondingly, an embodiment of the present disclosure further provides an electronic device, comprising: the foregoing computer readable storage medium; and one or more processors for executing a computer program in the computer readable storage medium.

The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the scope of the technical idea of the present disclosure. These simple variations are all within the scope of the disclosure.

It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not be further described in various possible combinations.

In addition, any combination of various embodiments of the present disclosure may be made as long as it does not deviate from the idea of the present disclosure, and should also be regarded as the disclosure of the present disclosure.

Claims

A battery equalization method, characterized in that the method comprises:

Obtaining an SOC value of the battery to be equalized in the battery pack;

Obtain the reference SOC value required for equalization;

Determining, according to the SOC value of the to-be-equalized unit cell, the reference SOC value, and a preset equalization duty ratio, a target equalization period of the to-be-equalized unit cell, wherein the equalization duty ratio is a unit period a ratio of the equalization period within the unit period to the unit period, the unit period including the equalization period and the sampling period;

According to the target equalization duration, the equalization of the cells to be equalized is controlled during the equalization period of the unit period.
The method according to claim 1, wherein the determining the unit cell to be equalized according to the SOC value of the unit cell to be equalized, the reference SOC value, and a preset equalization duty ratio Target equalization duration, including:

Determining the electric quantity difference according to ΔQ=ΔSOC×C n , wherein ΔQ is the electric quantity difference, and ΔSOC is a SOC difference value between the SOC value of the unit cell to be equalized and the reference SOC value, and C n is the The available capacity of the cell to be balanced;

The target equalization duration is determined according to t=ΔQ/(I×τ), where t is the target equalization duration, I is the equalization current of the cell to be equalized, and τ is the equalization duty.
The method according to claim 1 or 2, wherein the determining the unit to be equalized according to the SOC value of the unit cell to be equalized, the reference SOC value, and a preset equalization duty ratio The target balance time of the battery, including:

And pre-preparing between the SOC difference between the SOC value of the unit cell to be equalized and the reference SOC value, the equalization duty ratio, and the SOC difference value, the equalization duty ratio, and the target equalization duration Corresponding relationship is set to determine a target equalization duration of the unit to be balanced.
The method according to any one of claims 1-3, wherein the range of values of the SOC value is divided into a first interval in which the end value is 0 and the first SOC value according to the OCV-SOC curve of the corresponding single cell, The end value is a second interval of the first SOC value and the second SOC value, and the end value is the second SOC value and a third interval of 100%, and the method of calculating the SOC value includes the first calculation mode and the second a calculation manner, the first calculation manner corresponds to the first interval and the third interval, and the second calculation manner corresponds to the second interval;

Obtain the SOC value of each single battery in the battery pack, including:

Determining, according to the first calculation manner, the SOC value of the single battery for any one of the battery cells;

When the SOC value determined according to the first calculation manner belongs to the second interval, the SOC value of the single battery is re-determined according to the second calculation manner.
The method according to claim 4, wherein said first calculation mode is a manner in which said single cell calculates a SOC value last time.
The method according to claim 4, wherein the first calculation method is an ampere-hour integration method or an ampere-time integration method combined with a voltage correction method, and the second calculation method is an ampere-hour integration method and an ampere-hour integration method. A calculation method different from the first calculation method in the voltage correction method is combined.
The method according to any one of claims 1 to 6, wherein the reference SOC value is a minimum value among SOC values of the individual cells, a maximum value of each SOC value of each unit cell, or each order The average of the SOC values of the body batteries.
The method according to any one of claims 1 to 7, wherein the controlling the equalization of the cells to be equalized during the equalization period of the unit period comprises:

If the reference SOC value is a minimum value among the SOC values of the individual cells, the cell to be equalized is discharged during the equalization period of the unit period; or

If the reference SOC value is the maximum value of the SOC values of the individual cells, the cell to be equalized is controlled to be charged during the equalization period of the unit period; or

If the reference SOC value is an average value among the SOC values of the individual cells, when the SOC value of the cell to be balanced is greater than the reference SOC value, the waiting period is controlled during the equalization period of the unit period The cell battery is discharged, and when the SOC value of the cell to be equalized is less than the reference SOC value, the cell to be equalized is controlled to be charged during the equalization period of the unit period.
The method according to any one of claims 1-8, wherein the method further comprises:

Determining the cells to be equalized from the battery pack according to performance parameters of each of the battery cells in the battery pack, wherein the performance parameters include an SOC value, an internal resistance value, a self-discharge rate value, and a voltage At least one of a rate of change, a rate of change in power, and a rate of change in time.
A battery equalization system, comprising: an equalization module, an acquisition module, and a control module,

The collecting module is configured to collect battery information of a battery pack, and the battery information is used to determine an SOC value of each single battery in the battery pack;

The control module is configured to acquire an SOC value of the unit cell to be equalized in the battery group; obtain a reference SOC value required for equalization; and according to the SOC value of the unit battery to be equalized, the reference SOC value, and a pre- Determining a duty ratio of the target equalization time of the unit to be equalized, wherein the equalization duty ratio is a ratio of an equalization period in a unit period to the unit period, and the unit period includes the And an equalization period and a sampling period; and, according to the target equalization period, controlling the equalization of the cells to be equalized during the equalization period of the unit period.

The equalization module is configured to equalize the to-equalize cells.
The battery equalization system according to claim 10, wherein the control module is configured to:

Determining the electric quantity difference according to ΔQ=ΔSOC×C n , wherein ΔQ is the electric quantity difference, and ΔSOC is a SOC difference value between the SOC value of the unit cell to be equalized and the reference SOC value, and C n is the The available capacity of the cell to be balanced;

The target equalization duration is determined according to t=ΔQ/(I×τ), where t is the target equalization duration, I is the equalization current of the cell to be equalized, and τ is the equalization duty.
The battery equalization system according to claim 10 or 11, wherein the control module is configured to:

And pre-preparing between the SOC difference between the SOC value of the unit cell to be equalized and the reference SOC value, the equalization duty ratio, and the SOC difference value, the equalization duty ratio, and the target equalization duration Corresponding relationship is set to determine a target equalization duration of the unit to be balanced.
The battery equalization system according to any one of claims 10 to 12, characterized in that the value range of the SOC value is divided into the first value of the end value of 0 and the first SOC value according to the OCV-SOC curve of the corresponding single battery. The interval, the end value is a second interval of the first SOC value and the second SOC value, and the end value is the second SOC value and a third interval of 100%, and the method for calculating the SOC value includes the first calculation mode and a second calculation manner, the first calculation manner corresponds to the first interval and the third interval, and the second calculation manner corresponds to the second interval;

The control module is used to:

Determining, by the first calculation manner, the SOC value of the to-be-equalized unit battery for any one of the battery cells;

When the SOC value determined according to the first calculation manner belongs to the second interval, the SOC value of the to-be-equalized unit battery is re-determined according to the second calculation manner.
The battery equalization system according to claim 13, wherein the first calculation mode is a manner in which the single battery calculates the SOC value last time.
The battery equalization system according to claim 13, wherein the first calculation method is an ampere-hour integration method or an ampere-time integration method combined with a voltage correction method, and the second calculation method is an ampere-hour integration method and an ampere-hour method The integration method is combined with a calculation method different from the first calculation method in the voltage correction method.
The battery equalization system according to any one of claims 10-15, wherein the control module is further configured to:

Determining the cells to be equalized from the battery pack according to performance parameters of each of the battery cells in the battery pack, wherein the performance parameters include an SOC value, an internal resistance value, a self-discharge rate value, and a voltage At least one of a rate of change, a rate of change in power, and a rate of change in time.
The battery equalization system according to any one of claims 10 to 16, wherein the control module is connected to an acquisition module and an equalization module corresponding to the same single cell through a channel, and the control module is used for determining When the single battery connected to the control module does not need to be equalized, the control module is controlled to be connected with the corresponding sampling module; or

The control module is further configured to: when the cell connected to the control module needs to be equalized, the acquiring module and the equalization module time-multiplex the channel.
The battery equalization system according to claim 17, wherein the control module comprises a control chip, and the control chip is connected to the acquisition module and the equalization module corresponding to the same single cell through one pin and the one channel. .
The battery equalization system according to any one of claims 10-16, wherein the control module is respectively connected to the acquisition module and the equalization module corresponding to the same single cell through two channels.
The battery equalization system according to claim 19, wherein the control module comprises a control chip, and the control chip is respectively connected to an acquisition module and an equalization module corresponding to the same single cell through two pins, Two pins are in one-to-one correspondence with the two channels.
A vehicle characterized by comprising: a battery pack and the battery equalization system according to any one of claims 10-20.
A computer readable storage medium having stored thereon computer program instructions, wherein the computer program instructions, when executed by a processor, implement the method of any of claims 1-9.
An electronic device, comprising:

The computer readable storage medium of claim 22;

One or more processors for executing a computer program in the computer readable storage medium.