TW202132802A - Short-circuit monitoring method, system and device for single battery in power battery - Google Patents

Abstract

The invention relates to the technical field of battery short-circuit monitoring, particularly provides a short-circuit monitoring method, system and device for a single battery in a power battery, and aims to solve the problem of how to accurately monitor whether the single battery in the power battery is short-circuited. According to the invention, the deviation degree of each single voltage relative to the overall distribution of all single voltages within a certain time length is calculated; whether the single batteries are short-circuited or not is judged according to the deviation degrees; whether the single batteries are short-circuited or not can be analyzed according to the long-time and large-quantity single voltage of the power batteries under various conditions such as low-current charging, high-current charging, electric automobile stillness and electric automobile operation; the accuracy of monitoring the short circuit of the single battery in the power battery is improved, and the problem that the accuracy of a monitoring result is reduced due to the fact that whether the single battery is short-circuited or not cannot be monitored during large-current charging and electric vehicle running in the prior art is solved.

Description

Short circuit monitoring method, system and device of single battery in power battery

The invention relates to the technical field of battery short-circuit monitoring, in particular to a method, system and device for short-circuit monitoring of a single cell in a power battery.

The power battery in an electric vehicle may be thermally out of control due to a short circuit during charging and discharging, thereby endangering the safety of the power battery and the passengers in the electric vehicle. For example: when the power battery is in extreme conditions such as overcharge, overdischarge, high temperature charging and overcurrent, the single cells (cells) in the power battery may produce dendrites. If the dendrites produced by a single battery and Contact with other single cells, these single cells may short-circuit, and the short-circuited single cell will increase its temperature due to the excessive short-circuit current. If the temperature of the short-circuited single battery is too high, it may also cause short-circuits and temperature rises in other surrounding single batteries, thereby increasing the risk of thermal runaway of the power battery. In addition, when conductive particles are entrained in the power battery, the diaphragm is damaged, and the local stress is too large, it may also cause a short circuit in the single battery, which increases the risk of thermal runaway.

At present, the short-circuit monitoring method of the single battery in the power battery is mainly to monitor whether the power battery is short-circuited through the battery management system in the electric vehicle when the power battery is charged with a small current and when the electric vehicle is stationary. When charging and electric vehicles are running, it is impossible to monitor whether the single cells in the power battery are short-circuited.

Correspondingly, a new power battery short-circuit test solution is needed in this field to solve the above-mentioned problems.

In order to overcome the above shortcomings, the present invention is proposed to provide a short-circuit monitoring method, system and device for single cells in a power battery that solves or at least partially solves the problem of how to accurately monitor whether the single cells in the power battery are short-circuited.

In a first aspect, a method for short-circuit monitoring of a single cell in a power battery is provided, the method including:

Obtain the corresponding cell voltage of each cell in the power battery received within a certain period of time, and calculate the corresponding cell voltage of each cell within the certain period of time relative to all the cell voltages received The deviation of the overall distribution;

According to the deviation degree corresponding to each cell voltage, it is determined whether the power battery has a cell short circuit; if it is, an alarm message is output.

Among them, “get the corresponding cell voltage of each cell in the power battery received within a certain period of time, and calculate the corresponding cell voltage of each cell within the certain period of time relative to all the received cell voltages. The step of "the degree of deviation of the overall distribution of the cell voltage" specifically includes: taking the preset battery short-circuit monitoring time as the time starting point, obtaining all the data received within the preset first time period after the preset battery short-circuit monitoring time. According to the first cell voltage corresponding to each single cell in the power battery, the first deviation degree of each first cell voltage corresponding to the overall distribution of all the first cell voltages is calculated respectively.

Wherein, the step of "determining whether the power battery has a single battery short circuit according to the respective deviation degree corresponding to each single cell voltage" specifically includes: judging whether the first deviation degree corresponding to all the first single cell voltages is less than Or equal to a preset deviation threshold; if yes, it is determined that no single battery short circuit has occurred in the power battery.

Wherein, the step of "determining whether the power battery has a single battery short circuit according to the deviation degree corresponding to each of the individual cell voltages" further includes:

When the first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, the preset battery short-circuit monitoring time is used as the time starting point to obtain the preset battery short-circuit monitoring time The second cell voltage corresponding to each cell in the power battery received within the preset second time period is calculated, and the corresponding second cell voltage of each second cell voltage is calculated with respect to all the second cell voltages. The second degree of deviation of the overall voltage distribution;

According to the first degree of deviation and the second degree of deviation, judging whether the power battery has a single battery short circuit;

The preset second duration is greater than the preset first duration.

Wherein, the step of "determining whether the power battery has a single battery short circuit based on the first deviation degree and the second deviation degree" specifically includes:

Arranging the second degree of deviation and the first degree of deviation in the order of the cell voltage receiving time from first to last to obtain an array of deviation degrees;

Perform linear regression calculation on the deviation degree in the deviation degree array to obtain a linear regression curve equation and a linear fit degree;

Determine whether the linear fit is greater than the preset first fit threshold; if so, obtain the slope value of the corresponding linear regression curve according to the linear regression curve equation

Determine whether the slope value is greater than a preset slope threshold; if it is, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit.

Wherein, it further includes: if the linear fit is less than or equal to the preset first fit threshold, performing polynomial fitting calculation on the deviation in the deviation array to obtain a second-order polynomial fitting curve equation And polynomial fit;

Judging whether the polynomial fit degree is greater than a preset second degree of fit threshold;

If the degree of fit of the polynomial is greater than the preset second degree of fit threshold, the coefficient corresponding to the second-order term in the polynomial fitting curve equation is obtained and it is determined whether the coefficient is greater than zero; if so, it is determined that the power battery is The single battery is short-circuited; if not, it is determined that the power battery does not have a single battery short-circuit;

If the polynomial degree of fit is less than or equal to the preset second degree of fit threshold, it is determined that the power battery does not have a single battery short circuit.

Wherein, the step of “respectively calculating the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time” specifically includes:

Calculate the deviation degree according to the method shown in the following formula:

是在所述一定時長內第i時刻接收到的所述動力電池中第j個單體電池的單體電壓，所述devi_i_j是所述單體電壓

對應的偏離度，所述

是在所述一定時長內第i時刻接收到的所有單體電壓的均值，所述

是在所述一定時長內第i時刻接收到的所有單體電壓的標準差。Said

Is the cell voltage of the j-th cell in the power battery received at the i-th time within the certain period of time, and the devi_i_j is the cell voltage

Corresponding degree of deviation, the

Is the average value of all cell voltages received at the i-th time within the certain period of time, the

It is the standard deviation of all cell voltages received at the i-th time within the certain period of time.

Wherein, before the step of “respectively calculating the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time”, the method further includes:

Acquiring each working current of the power battery received within the certain period of time;

Arranging the working currents in the order of current receiving time from first to last to obtain a working current array, and performing differential calculation on the working currents in the working current array to obtain the respective difference corresponding to each working current;

Acquiring the working current whose difference is greater than a preset difference threshold and the data receiving time corresponding to the working current;

Obtain and delete the corresponding cell voltage of each cell received within a certain period of time before and after the data receiving time within the certain period of time, and then execute the step "calculated separately according to the remaining cell voltages" The deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time".

In a second aspect, a short-circuit monitoring system for a single battery in a power battery is provided, the system including:

Deviation degree calculation device, which is configured to obtain the corresponding cell voltage of each cell in the power battery received within a certain time period, and calculate the corresponding cell voltage of each cell voltage within the certain time period. The degree of deviation from the overall distribution of all cell voltages received;

The battery short-circuit judging device is configured to judge whether the power battery has a single-cell short-circuit according to the deviation degree corresponding to each of the individual cell voltages; if so, output an alarm message.

Wherein, the deviation degree calculation device includes a first deviation degree calculation module, and the first deviation degree calculation module is configured to perform the following operations: taking a preset battery short-circuit monitoring moment as a time starting point, obtaining the The first cell voltage corresponding to each single cell in the power battery received within the preset first time period after the battery short-circuit monitoring moment is calculated, and the corresponding first cell voltage of each first cell voltage is calculated respectively relative to all the first cell voltages. The first degree of deviation of the overall voltage distribution of the first cell.

Wherein, the battery short-circuit judging device includes a first short-circuit judging module, and the first short-circuit judging module is configured to perform the following operations: judging whether the first deviation degrees corresponding to all the first cell voltages are less than or equal to a preset Deviation threshold; if yes, it is determined that no single cell short circuit has occurred in the power battery.

Wherein, the deviation degree calculation device includes a second deviation degree calculation module, and the battery short-circuit judgment device includes a second short-circuit judgment module;

The second degree of deviation calculation module is configured to use the preset battery short-circuit monitoring moment as a time starting point to obtain the preset second time period before the preset battery short-circuit monitoring moment. The second cell voltage corresponding to each single cell in the power battery is calculated separately, and the second deviation degree corresponding to each second cell voltage with respect to the overall distribution of all second cell voltages is calculated respectively; wherein, the prediction Set the second duration to be greater than the preset first duration;

The second short-circuit judgment module is configured to, when the first short-circuit judgment module judges that a first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, according to the first deviation And the second deviation degree to determine whether the power battery has a single battery short circuit.

Wherein, it also includes that the second short-circuit judgment module is configured to perform the following operations:

Arranging the second degree of deviation and the first degree of deviation in the order of the cell voltage receiving time from first to last to obtain an array of deviation degrees;

Perform linear regression calculation on the deviation degree in the deviation degree array to obtain a linear regression curve equation and a linear fit degree;

Determine whether the linear fit is greater than the preset first fit threshold; if so, obtain the slope value of the corresponding linear regression curve according to the linear regression calculation result;

Determine whether the slope value is greater than a preset slope threshold; if it is, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit.

Wherein, it also includes that the second short-circuit judgment module is configured to perform the following operations:

If the linear fit is less than or equal to the preset first fit threshold, perform polynomial fitting calculation on the deviation in the deviation array to obtain the second-order polynomial fitting curve equation and the polynomial fit threshold ；

Judging whether the polynomial fit degree is greater than a preset second degree of fit threshold;

If the degree of fit of the polynomial is greater than the preset second degree of fit threshold, obtain the coefficient corresponding to the second-order term in the second-order polynomial fitting curve equation and determine whether the coefficient is greater than zero; The power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit;

If the polynomial degree of fit is less than or equal to the preset second degree of fit threshold, it is determined that the power battery does not have a single battery short circuit.

Wherein, it also includes that the deviation degree calculation device is configured to perform the following operations:

Calculate the deviation degree according to the method shown in the following formula:

是在所述一定時長內第i時刻接收到的所述動力電池中第j個單體電池的單體電壓，所述

是所述單體電壓

對應的偏離度，所述

是在所述一定時長內第i時刻接收到的所有單體電壓的均值，所述

是在所述一定時長內第i時刻接收到的所有單體電壓的標準差。Among them, the

Is the cell voltage of the j-th cell in the power battery received at the i-th time within the certain period of time, the

Is the cell voltage

Corresponding degree of deviation, the

Is the average value of all cell voltages received at the i-th time within the certain period of time, the

It is the standard deviation of all cell voltages received at the i-th time within the certain period of time.

Wherein, it also includes that the deviation degree calculation device is configured to perform the following operations:

Acquiring each working current of the power battery received within the certain period of time;

Arranging the working currents in the order of current receiving time from first to last to obtain a working current array, and performing differential calculation on the working currents in the working current array to obtain the respective difference corresponding to each working current;

Acquiring a working current whose difference is greater than a preset difference threshold and acquiring a data receiving time corresponding to the working current;

Obtain and delete the corresponding cell voltage of each cell received within a certain period of time before and after the data receiving time within the certain period of time, and then execute the step "calculated separately according to the remaining cell voltages" The deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time".

In a third aspect, a storage device is provided. The storage device stores a plurality of program codes, and the program codes are adapted to be loaded and run by a processor to perform any one of the above-mentioned short-circuit monitoring of a single battery in a power battery method.

In a fourth aspect, a control device is provided. The control device includes a processor and a storage device. The storage device is adapted to store multiple pieces of program code, and the program code is adapted to be loaded and run by the processor to execute any one of the foregoing. The short-circuit monitoring method of the single battery in the power battery described in the item.

The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

In the technical solution of the present invention, through the statistical analysis of the long-term and large-data volume cell voltages, it is concluded that the voltage of each cell of each cell is relative to all the cells in a relatively long period of time. The deviation of the average value of the cell voltage of the battery. If the deviation of the cell voltage of all the single cells is less than or equal to the preset deviation threshold, it means that no single cell has a short circuit. Based on the average value of the cell voltage of all cells, analyze the deviation of the cell voltage of each cell from the average value and use the deviation to indicate the voltage change state of each cell voltage, even if some cells The battery has a short ohmic polarization under the action of a large charging current or discharging current (for example: the cell voltage of some single cells decreases and/or the cell voltage of some single cells increases), but all cells The average cell voltage of the battery will also change accordingly, so as long as all cell voltages are still near the average cell voltage, it can be judged that no cell short circuit has occurred. If the deviation of a part of the cell voltage of a single battery with respect to the average value of the cell voltages of all the single cells is greater than the preset deviation threshold, it indicates that the single battery may have a short circuit. In this regard, the present invention further analyzes the deviation of the cell voltage for a longer time and more data volume, and obtains the deviation of the cell voltage of this single cell from all the cell voltages within the longer time range. The change trend of the average value, according to the change trend to determine whether a single battery short circuit occurs. From the above analysis, it can be seen that the deviation of the cell voltage is only related to the average value of the cell voltage of all the cells, and only the comparison result of the deviation and the threshold of the deviation is considered when analyzing whether the short circuit of the cell occurs according to the deviation. As well as the variation trend of the degree of deviation, the accuracy of the short-circuit monitoring result will not be affected regardless of whether the single battery has ohmic polarization. Therefore, the present invention is not only suitable for low-current charging of the power battery and short-circuit monitoring of the single battery when the vehicle is stationary. It is also suitable for high-current charging of power batteries and short-circuit monitoring of single batteries during vehicle driving.

Hereinafter, some embodiments of the present invention will be described with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention.

In the description of the present invention, "module" and "processor" may include hardware, software, or a combination of both. A module can include hardware circuits, various suitable sensors, communication ports, and memory, and can also include software parts, such as program codes, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and/or signal processing functions. The processor can be implemented in software, hardware, or a combination of the two. The non-transitory computer-readable storage medium includes any suitable medium that can store program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, and so on. The term "A and/or B" means all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one of A or B" or "at least one of A and B" has a meaning similar to "A and/or B" and may include only A, only B, or A and B. The terms "a", "this", and "some" in the singular form may also include plural forms.

Here, some terms involved in the present invention will be explained first.

A single battery refers to the basic battery unit that constitutes a power battery, and multiple single batteries are connected in series and parallel to form a power battery.

The cell voltage refers to the voltage of the cell.

The deviation of a cell voltage from the overall distribution of all cell voltages refers to the degree to which this cell voltage deviates from the average value of all cell voltages. If the deviation of the corresponding cell voltage of a single battery is smaller, it indicates that the risk of short circuit of the single battery is lower.

The working current of the power battery refers to the working current (charging current or discharging current) of the power battery during the charging and discharging process.

Because the resistance value of each single battery in the power battery is not the same, there will be a certain difference (voltage deviation) in the single voltage of each single battery. For the power battery that does not have a single battery short circuit, these The voltage deviation is very small, that is, the single battery in the power battery has a higher voltage consistency. However, when a single cell short circuit occurs in a power battery, the voltage deviation between a part of the cell voltage will be relatively large, resulting in a lower voltage consistency of the single cell. The prior art method for monitoring the short circuit of the single battery in the power battery is to use the above-mentioned voltage change law of the single battery to monitor whether the power battery has a single battery short circuit, that is, to detect the voltage consistency of the single battery in the power battery. The detection result determines whether the power battery has a single battery short circuit. However, when using a large current to charge a power battery, a large charging current will cause a short ohmic polarization of the single battery (the phenomenon of electrode potential deviating from the equilibrium potential caused by the ohmic resistance of the battery), and ohmic polarization may It will reduce the voltage consistency of the single battery (for example: the single voltage of a part of the single battery decreases and/or the single voltage of a part of the single battery increases, thereby causing the voltage consistency of the single battery to decrease). Using the voltage consistency test result to determine whether a single battery short circuit occurs will cause a misjudgment. Therefore, this method is not suitable for detecting whether a power battery has a single battery short circuit when the power battery is charged with a large current. Similarly, during the driving of the vehicle, due to the complex and changeable driving conditions of the vehicle, the discharge current of the power battery may be relatively large, and a relatively large discharge current will also cause a short ohmic polarization of the single battery. The method is also not suitable for detecting whether the power battery has a single battery short circuit during the driving of the vehicle.

In the embodiment of the present invention, the cell voltage corresponding to each cell in the power battery within a certain period of time is extracted, and the corresponding cell voltage of each cell voltage during this period of time is calculated with respect to all the cells received. The deviation of the overall voltage distribution, and based on these deviations, determine whether the power battery has a single battery short circuit and output an alarm message. An example: The battery management system in an electric vehicle detects the cell voltage of each cell in the power battery in real time, and sends the detected cell voltage to the back-end server connected to the electric vehicle network, and the back-end server receives and stores each cell voltage. Each cell in the power battery corresponds to the cell voltage. After the background server determines that the power battery is short-circuited by the single battery by performing the above operations, it outputs an alarm message to the electric vehicle to remind the electric vehicle user that the power battery has the risk of a single battery short-circuit and conduct timely maintenance.

In the embodiment of the present invention, by performing statistical analysis on the long-term and large-data-volume single-cell voltage, it is obtained that the single-cell voltage of each single-cell battery is relative to the single-cell voltage of all the single-cell batteries within a relatively long period of time. If the deviation of the cell voltage of all the single cells is less than or equal to the preset deviation threshold, it means that no single cell has a short circuit. Based on the average value of the cell voltage of all cells, analyze the deviation of the cell voltage of each cell from the average value and use the deviation to indicate the voltage change state of each cell voltage, even if some cells The battery has a short ohmic polarization under the action of a large charging current or discharging current (for example: the cell voltage of some single cells decreases and/or the cell voltage of some single cells increases), but all cells The average cell voltage of the battery will also change accordingly, so as long as all cell voltages are still near the average cell voltage, it can be judged that no cell short circuit has occurred.

If the deviation of a part of the cell voltage of a single battery with respect to the average value of the cell voltages of all the single cells is greater than the preset deviation threshold, it indicates that the single battery may have a short circuit. However, because the cell voltage of a single battery will fluctuate normally during the charging and discharging process, if the deviation of certain cell voltages is greater than the preset deviation threshold, it may be caused by a short circuit. Misjudgment, therefore, the present invention further analyzes the deviation of the cell voltage of a longer time and more data volume, and obtains the deviation of the cell voltage of this single cell from all the cell voltages within this longer time range. The change trend of the average value, according to the change trend to determine whether a single battery short circuit occurs. Specifically, the corresponding cell voltage of each cell in the power battery can be extracted in time intervals, and first judged according to the deviation of the cell voltage in the first time period (the deviation of the cell voltage in a shorter time range) Whether the power battery has a single battery short circuit, if the deviation of a certain single cell voltage is greater than the preset deviation threshold, the deviation of the single cell voltage in the first and second time periods is obtained at the same time (within a longer time range) The deviation degree of the single cell voltage), and then perform linear regression calculation on all the deviation degrees of this single battery in the above-mentioned long time range. If the slope value of the linear regression curve calculated by linear regression is less than zero (linear decreasing function), it means that the cell voltage of this cell is gradually approaching the average cell voltage of all cells, and the above part deviates The voltage of a single cell with a degree greater than the deviation threshold is only the normal fluctuation of the single battery during the charging and discharging process, and the single battery is not short-circuited. If the slope of the linear regression curve is greater than zero (linear increasing function), it means that the cell voltage of this single battery is gradually moving away from the average value of the cell voltages of all the single cells. In this case, you can use the slope value and preset The slope threshold of the comparison result is used to further determine whether the single battery is short-circuited. The specific method is to test the power battery before short-circuit monitoring to obtain the slope of the corresponding linear regression curve when a single battery is short-circuited, and set the slope threshold according to the slope (the slope threshold is less than the slope and the slope threshold is greater than zero) . In short-circuit monitoring, after obtaining the slope corresponding to a single battery, call the slope threshold and compare the slopes. If the slope corresponding to the single battery is greater than or equal to the slope threshold, it indicates that the single battery is in a short-circuit state. If the corresponding slope of the single battery is less than the slope threshold, it indicates that the single battery is still in the normal voltage change state, and the single battery has not short-circuited.

From the above analysis, it can be seen that the deviation of the cell voltage is only related to the average value of the cell voltage of all the cells, and only the comparison result of the deviation and the threshold of the deviation is considered when analyzing whether the short circuit of the cell occurs according to the deviation. As well as the variation trend of the degree of deviation (the slope of the linear regression curve), the accuracy of the short-circuit monitoring result will not be affected regardless of whether the single battery has ohmic polarization or not. Therefore, the present invention is not only suitable for low-current charging of power batteries and stationary vehicles The single battery short-circuit monitoring at the time is also suitable for high-current charging of the power battery and the single-battery short-circuit monitoring during the driving of the vehicle.

Referring to FIG. 4, FIG. 4 is a schematic diagram of an application scenario of an embodiment involved in the technical solution of the present invention. The electric vehicle 21 is provided with a communication device, a power battery, and a battery management system (Battery Management System, BMS) capable of detecting the battery parameters of the power battery (including but not limited to: the working current of the power battery and the cell voltage of the single battery) , The electric vehicle 21 establishes a communication connection with the background server 22 through a communication device (including but not limited to: a WIFI communication device and a 4G communication device ((a communication device based on the fourth-generation mobile communication and its technology))). The battery management system detects the cell voltage of each cell in the power battery in real time, and the electric vehicle 21 sends the detected cell voltage to the background server 22 in real time through the communication device. The back-end server 22 performs data analysis on the received cell voltage, and when it is analyzed that the power battery has a single battery short circuit, it sends an alarm message to the electric vehicle 21 (for example: the current power battery has a single battery short circuit) to remind the electric vehicle The driver within 21 should check and repair the power battery in time.

Further, the back-end server 22 can also communicate with the terminals of the users of the electric vehicles 21 (including but not limited to: mobile phones and tablets) and/or the terminals of the service providers of the electric vehicles (including but not limited to: computer equipment). After the short circuit of the single battery of the power battery, it sends an alarm message to the user’s terminal and/or sends an alarm message to the terminal of the electric vehicle service provider according to the current power battery’s identification code (including but not limited to: the ID number of the power battery). : The power battery whose ID number is "Battery111" has a single battery short circuit) to remind the service provider of electric vehicles to check and repair the power battery in time.

Referring to FIG. 1, FIG. 1 is a schematic flow diagram of the main steps of a method for short-circuit monitoring of a single cell in a power battery according to an embodiment of the present invention. As shown in Figure 1, the method for short-circuit monitoring of a single cell in a power battery in an embodiment of the present invention mainly includes the following steps:

Step S101: Receive the individual voltage corresponding to each individual battery in the power battery.

In one embodiment, the cell voltage of each cell in the power battery detected and sent by a cell voltage detection device such as a battery management system can be directly received, or other cell voltages connected to the cell voltage detection device network can be received. The unit voltage of the power battery sent by the device, these devices can receive/store the unit voltage of the power battery detected by the unit voltage detection device. One example: directly receiving the corresponding cell voltage of each cell in the power battery sent by the battery management system of the electric vehicle; another example: receiving each cell voltage in the power battery sent by the on-board control device of the electric vehicle Corresponding to the cell voltage, the on-board control device is connected to the battery management system network and can receive/store the cell voltage of the power battery detected by the battery management system.

Step S102: Obtain the corresponding cell voltage of each cell in the power battery received within a certain period of time, and respectively calculate the corresponding cell voltage of each cell voltage within the certain period of time relative to all the received cell voltages. The deviation of the overall distribution of the cell voltage.

In the embodiment of the present invention, the degree of deviation of a cell voltage relative to the overall distribution of all cell voltages refers to the degree to which this cell voltage deviates from the average value of all cell voltages.

（1）In one embodiment, the method shown in the following formula (1) may be used to calculate the deviation of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time:

(1)

The meaning of each parameter in formula (1) is:

是在所述一定時長內第i時刻接收到的一個動力電池中第j個單體電池的單體電壓，

是單體電壓

對應的偏離度，

是在所述一定時長內第i時刻接收到的這個動力電池的所有單體電壓的均值，

是在所述一定時長內接收到的這個動力電池的單體電壓的總數；

是在所述一定時長內第i時刻接收到的所有單體電壓的標準差，

。

Is the cell voltage of the j-th cell in a power battery received at the i-th time within the certain period of time,

Is the cell voltage

The corresponding deviation,

Is the average value of all cell voltages of this power battery received at the i-th time within the certain period of time,

Is the total number of cell voltages of this power battery received within the certain period of time;

Is the standard deviation of all cell voltages received at the i-th time within the certain period of time,

.

的物理意義是以標準差

為單位，單體電壓

在均值

之上有多少個標準差

，或是在均值

之下有多少個標準差

，該偏離度

能夠清楚表明單體電壓

偏離所有單體電壓總體分佈的程度。The deviation degree calculated by the above formula (1) in the embodiment of the present invention

The physical meaning of is the standard deviation

Unit, cell voltage

In mean

How many standard deviations above

, Or at the mean

How many standard deviations below

, The deviation

Can clearly indicate the cell voltage

The degree of deviation from the overall voltage distribution of all cells.

In one embodiment, before separately calculating the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time, a cell voltage screening step may also be included, by The cell voltage screening step can delete unreal and effective cell voltages caused by data quality problems such as data transmission asynchronous, data loss or misalignment, thereby improving the accuracy of short-circuit monitoring. This step specifically includes:

Step 1: Obtain each operating current of the powered battery received within the certain period of time. It should be noted that the "definite time period" in this embodiment is the same as the "definite time period" in the foregoing embodiment.

Step 2: Arrange the working currents in the order of the current receiving time from first to last to obtain a working current array, and perform differential calculation on the working currents in the working current array to obtain the respective difference corresponding to each working current.

In this embodiment, a first-order difference calculation or a multi-order difference calculation can be performed on the working currents in the working current array to obtain the respective difference corresponding to each working current.

Step 3: Obtain the working current corresponding to the difference greater than the preset difference threshold among the differences obtained in Step 2, and obtain the data receiving time corresponding to the working current.

Step 4: Obtain and delete the corresponding cell voltage of each cell received within a certain period of time before and after the data reception time within the certain period of time, and then execute the step according to the remaining cell voltage. Calculate the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time".

，將這些工作電流按照接收時間由先至後的順序進行排列得到工作電流數組

，對工作電流數組中的每個工作電流進行差分計算，得到每個工作電流各自對應的差分

，其中，大於預設差分閾值的差分是

，該差分

對應的工作電流

的數據接收時間是下午5點50分。若“數據接收時間前後一定時間範圍”是下午5點50分的前後10分鐘內，則獲取下午5點40分至下午6點之間的單體電壓並刪除這些單體電壓，隨後計算剩下的單體電壓（下午5點至5點39分之間以及下午6點01分至下午7點之間接收到的單體電壓）的偏離度。An example: Assuming that the current time is 8:00 pm on January 1, 2020, the preset battery short-circuit monitoring time is based on the current time as the starting point, 3 hours before the current time (January 1, 2020 5 pm), the preset first time period is 2 hours, then the "preset first time period after the preset battery short-circuit monitoring time" refers to 5 pm to 7 pm, get the reception during this time Working current of power battery A

, Arrange these working currents in the order of receiving time from first to last to get the working current array

, To calculate the difference of each working current in the working current array, and get the corresponding difference of each working current

, Where the difference greater than the preset difference threshold is

, The difference

Corresponding working current

The data reception time is 5:50 pm. If the "a certain time range before and after the data reception time" is within 10 minutes before and after 5:50 pm, obtain the cell voltages between 5:40 pm and 6 pm and delete these cell voltages, and then calculate the remaining The deviation of the cell voltage (the cell voltage received between 5 pm and 5:39 pm and between 6:01 pm and 7 pm).

Data quality issues such as unsynchronized data transmission, data loss or misalignment will cause some cell voltages to have a large difference in voltage value compared with other cell voltages received before and after it. These cell voltages cannot truly reflect the cell battery. In the voltage state at the corresponding receiving time, if these monomer voltages are used to determine whether a single battery short circuit occurs, a misjudgment may occur, and these monomer voltages need to be deleted. Considering that the difference can represent the variation between discrete quantities, the embodiment of the present invention calculates the respective difference of each working current to obtain the variation between all adjacent working currents, and the current value can be determined according to the difference value. Abnormal fluctuations (the differential value is greater than the preset differential threshold) operating current, these operating currents and other operating currents received before and after the current value is relatively large difference, and the receiving time of these operating currents correspond to the monomer received The voltage is the above-mentioned cell voltage that cannot truly reflect the voltage state of the cell that needs to be deleted. Further, in order to delete as much as possible all potential cell voltages that cannot truly reflect the voltage state of the cell and improve the accuracy of short-circuit monitoring, all cell voltages received within a certain time range before and after the receiving time of the above operating current can be Both are deleted.

Further, in one embodiment, after the cell voltage screening step, the filtered cell voltage may be voltage filtered, and the deviation degree of the cell voltage after the voltage filtering may be calculated, so as to further improve the accuracy of short circuit monitoring. In one embodiment, the cell voltage can be filtered before the cell voltage screening step, and then the cell voltage after the voltage filtering is screened by performing the cell voltage screening step, and the cell voltage after the screening is performed The deviation calculation further improves the accuracy of short-circuit monitoring.

Step S103: According to the deviation degree corresponding to each single cell voltage, it is judged whether the power battery has a single cell short circuit. Specifically, if it is determined that the power battery has a single battery short circuit, then go to step S104; if it is determined that the power battery does not have a single battery short circuit, then go to step S105.

In one embodiment, it can be determined whether a single battery short circuit occurs in the power battery according to the following steps:

Step 1: Taking the preset battery short-circuit monitoring time as the starting point of time, obtain the first order corresponding to each single cell in the power battery received within the preset first time period after the preset battery short-circuit monitoring time. Body voltage, respectively calculating the first deviation degree of each first cell voltage corresponding to the overall distribution of all first cell voltages.

An example: Assuming that the current time is 8:00 pm on January 1, 2020, the preset battery short-circuit monitoring time is based on the current time as the starting point, 3 hours before the current time (January 1, 2020 5 pm), the preset first time period is 2 hours, then "the preset first time period after the preset battery short-circuit monitoring time" refers to 5 pm to 7 pm, get the reception during this time The first cell voltage corresponding to each single cell in power battery A is calculated, and then the first cell voltage of each first cell in power battery A is calculated relative to all the received first cell voltages according to the method shown in formula (1). The first degree of deviation of the overall cell voltage distribution.

The preset first time period after the preset battery short-circuit monitoring time is a period of time before the current time and relatively close to the current time, during which the received cell voltage (first cell voltage) can be Approximately reflect the latest voltage state of the single battery, calculating and using the deviation of these single voltages (first deviation) can more accurately determine whether a single battery short circuit occurs.

Step 2: Determine whether the first deviation degrees corresponding to all the first cell voltages calculated in step 1 are less than or equal to the preset deviation degree threshold (the preset deviation threshold can be in the range of 1.5 to 10); If the first deviation degree corresponding to all the first single cell voltages is less than or equal to the preset deviation degree threshold, it is determined that no single cell short circuit has occurred in the power battery. If the first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, it can be determined that the power battery is short-circuited.

In the embodiment of the present invention, by performing long-term statistical analysis of the deviation degree of the cell voltage of each single cell with a large amount of data, it can be obtained that the cell voltage of this single cell deviates from the average value of all the cell voltages in a period of time. If the deviation of all cell voltages during this period is less than or equal to the preset deviation threshold, it indicates that the cell voltage of this single battery has not been abnormal during this period and is in normal working condition; if During this period of time, there are situations where the deviation of some cell voltages is greater than the preset deviation threshold, which indicates that the single battery may or may not be short-circuited. Therefore, when the deviation of some cell voltages is greater than the preset deviation threshold, further analysis is required to accurately determine whether a short circuit of the cell occurs.

Further, in one embodiment, when it is determined in step 2 that the first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, it is also possible to determine whether the power battery is short-circuited in the single cell according to the following steps:

Step 21: Taking the preset battery short-circuit monitoring time in the foregoing embodiment as the starting point of time, obtain the respective single cells of the power batteries received within the preset second time period before the preset battery short-circuit monitoring time For the corresponding second cell voltages, the second deviation degree of each second cell voltage corresponding to the overall distribution of all second cell voltages is calculated respectively. Wherein, the preset second duration is greater than the preset first duration in the foregoing embodiment. An example: the preset second duration is 1-10 times the preset first duration.

An example: Assuming that the current time is 8:00 pm on January 1, 2020, the preset battery short-circuit monitoring time is based on the current time as the starting point, 3 hours before the current time (January 1, 2020 5 pm), the preset second time is 3 hours, then "the preset second time before the preset battery short-circuit monitoring time" refers to 2 pm-5 pm, get the reception during this time The second cell voltage corresponding to each cell in power battery A is then calculated according to the method shown in formula (1). The second degree of deviation of the overall cell voltage distribution.

Step 22: According to the first degree of deviation and the second degree of deviation, determine whether the power battery has a single battery short circuit.

In the case that it is impossible to determine whether a single battery short circuit occurs according to the deviation of the single cell voltage in the first time period, the embodiment of the present invention is based on a longer time range (the time period composed of the first time period and the second time period). The deviation (the first deviation and the second deviation) of the cell voltage (the first cell voltage and the second cell voltage) within the range) can be used to evaluate the cell voltage in a longer time range. Deviation from the change trend of the average value of all cell voltages, according to this change trend, it can be further analyzed whether a cell short circuit occurs.

In an embodiment, the above step 22 may specifically include:

Step 221: Arrange the second degree of deviation and the first degree of deviation according to the order of the cell voltage receiving time to obtain an array of deviation degrees.

Step 222: Perform linear regression calculation on the deviation degree in the deviation degree array to obtain the linear regression curve equation and the linear fit degree. The degree of linear fit can indicate the credibility of the linear regression calculation results. The greater the degree of linear fit, the greater the possibility of linearizing these deviations, and the linear curve represented by the linear regression curve equation can be It reflects the changing trend of these deviations more truly; the smaller the linear fit, the less likely it is to linearize the deviations, and the linear curve represented by the linear regression curve equation cannot reflect more truly The trend of these deviations. The linear regression calculation method adopted in this embodiment is a conventional linear regression method in the field, and for the sake of concise description, it will not be repeated here.

An example: The first cell voltage of the single cell a of the 120 power battery A is received between 5 pm and 7 pm on January 1, 2020, and the 120 voltage is calculated according to the method shown in formula (1). The first degree of deviation corresponding to the first cell voltage; the second cell voltage of the single cell a of the 180 power battery A is received between 2 o'clock in the afternoon and 5 o'clock in the afternoon, according to the method shown in formula (1) Calculate the second degree of deviation corresponding to the 180 second cell voltages; arrange the 180 second degree of deviation and 120 first degree of deviation obtained from the above calculation according to the order of the cell voltage receiving time from first to last Get the deviation degree array. Perform linear regression calculation on 300 deviation degrees in the deviation degree array, and then obtain the linear regression equation and linear fit.

Step 223: Determine whether the linear fit obtained in step 222 is greater than a preset first fit threshold (the preset first fit threshold may have a value range of 0.3 to 1).

If the linear fit is greater than the preset first fit threshold, it indicates that the linear regression calculation result in step 222 has high credibility, and the linear curve represented by the linear regression curve equation can truly reflect these deviations. At this time, the slope value of the corresponding linear regression curve can be obtained according to the linear regression curve equation, and then it can be judged whether the slope value is greater than the preset slope threshold (the value range of the preset slope threshold can be 0.01 to 10 ); If yes, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit.

If the linear fit is less than or equal to the preset first fit threshold, it indicates that the reliability of the linear regression calculation result in step 222 is low. In order to simplify the processing logic of short-circuit monitoring and reduce the corresponding computational workload, When the linear fit is less than or equal to the preset first fit threshold, it can also be determined whether the power battery has a single battery short circuit according to the comparison result of the slope value of the linear regression curve and the preset slope threshold.

From the foregoing analysis, it can be seen that since the deviation of the cell voltage in the first time period is greater than the preset deviation threshold, the method of comparing the deviation of the cell voltage with the preset deviation threshold can no longer be used. To determine whether a single battery short circuit occurs. Considering that the deviations of all cell voltages are discrete quantities, the embodiment of the present invention performs linear regression calculation on the deviations of these discrete cell voltages, and obtains a linear regression that can characterize the variation trend of the deviations of the cell voltages. Curve equation and linear fit degree. Under the condition that the linear fit degree is greater than the preset first degree of fit threshold, the slope value of the linear regression curve equation is obtained, and this slope value is used as a characterization of the variation trend of the deviation degree of these monomer voltages A quantitative indicator, the larger the slope value, the greater the deviation of the cell voltage of the single cell from the average value of all cell voltages during this period of time. If the slope value is greater than the corresponding value when the single cell is short-circuited The slope value (the preset slope threshold value above) can immediately determine that the single battery has a short-circuit fault.

Further, in this embodiment, when the linear fit is less than or equal to the preset first fit threshold, in order to more accurately determine whether the power battery has a single battery short circuit, the following may be included after step 223 step:

Step 224: Perform polynomial fitting calculation on the deviation degrees in the deviation degree array obtained in step 221 to obtain the second-order polynomial fitting curve equation and the polynomial fitting degree. The second-order polynomial fitting curve equation refers to an equation in which the highest term in the polynomial fitting curve equation is the second degree. Similar to the function of linear fit, the degree of polynomial fit can indicate the credibility of the calculation result of polynomial fit. For the sake of brevity, it will not be repeated here. In addition, the polynomial fitting calculation method adopted in this embodiment is a conventional polynomial fitting method in the art, and for simplicity of description, it will not be repeated.

Step 225: Determine whether the polynomial fit obtained in step 224 is greater than the preset second fit threshold (the preset first fit threshold can range from 0.3 to 1); if so, obtain the second degree The coefficients corresponding to the second-order term in the polynomial fitting curve equation.

If the degree of polynomial fit is greater than the preset second degree of fit threshold, it indicates that the polynomial fitting calculation result in step 224 has high credibility, and the polynomial fitting curve can truly reflect the changing trend of the degree of deviation. At this time, it can be judged whether the coefficient corresponding to the second-order term (the coefficient of the highest term in the second-order polynomial fitting curve equation) is greater than zero; The body battery is short-circuited.

If the polynomial fit is less than or equal to the preset second fit threshold, it indicates that the reliability of the polynomial fit calculation result in step 224 is low. At the same time, it can be seen from the foregoing analysis that the linear regression calculation results of these deviations The credibility of the power battery is also relatively low. This situation indicates that these deviations are in an irregular fluctuation state, indicating that the cell voltage of the single battery in the power battery may be in a normal fluctuation state, so it can be determined that the power battery does not have a single cell. The battery is short-circuited.

In the case that the linear curve represented by the linear regression curve equation cannot truly reflect the change trend of these deviations, the embodiment of the present invention combines the linear regression calculation results and the polynomial calculation results to analyze at the same time, and can specifically determine the deviations. Which change trend is in, and then analyze whether the power battery has a single battery short circuit according to the judgment result, so as to avoid the misjudgment of the single battery short circuit caused when the linear fit is low.

In the following, the method of this embodiment is determined with reference to FIG. 2 to first determine that the first deviation corresponding to the first cell voltage is greater than the preset deviation threshold, and then at the same time according to the first deviation and the second corresponding to the second cell voltage. The deviation degree judges whether the power battery is short-circuited as an example for further details.

Step S201: Receive the respective cell voltage of each cell in the power battery sent by the battery management system in the electric vehicle.

Step S202: Using the preset battery short-circuit monitoring time as the starting point of time, obtain the first battery corresponding to each single cell in the power battery received within the preset first time period after the preset battery short-circuit monitoring time. Body voltage.

Step S203: Calculate the respective first deviation degrees of the voltages of each first cell relative to the overall distribution of the voltages of all the first cells respectively.

Step S204: Determine whether the first deviation degrees corresponding to all the first cell voltages are less than or equal to a preset deviation degree threshold. Specifically, if all the first deviation degrees are less than or equal to the preset deviation degree threshold, then go to step S216; if there is a certain first deviation degree greater than the preset deviation threshold, then go to step S205.

Step S205: Taking the preset battery short-circuit monitoring time as the starting point of time, obtain the second cell corresponding to each single cell in the power battery received within the preset second time period before the preset battery short-circuit monitoring time. Body voltage.

Step S206: Calculate the second degree of deviation corresponding to the voltage of each second cell relative to the overall distribution of the voltages of all the second cells respectively.

Step S207: Arranging the second deviation degree and the first deviation according to the order of the cell voltage receiving time to obtain the deviation degree array.

Step S208: Perform linear regression calculation on the deviation degree in the deviation degree array to obtain the linear regression curve equation and the linear fit degree.

Step S209: Determine whether the linear fit is greater than the preset first fit threshold; if so, go to step S210; if not, go to step S212.

Step S210: Obtain the slope value of the corresponding linear regression curve according to the linear regression curve equation.

Step S211: Determine whether the slope value is greater than the preset slope threshold; if yes, go to step S215; if not, go to step S216.

Step S212: Perform polynomial fitting calculation on the deviation degrees in the deviation degree array to obtain the second-order polynomial fitting curve equation and the polynomial fitting degree.

Step S213: Determine whether the polynomial fit degree is greater than the preset second degree of fit threshold; if yes, go to step S214; if not, go to step S216.

Step S214: Obtain the coefficient corresponding to the second-order term in the second-order polynomial fitting curve equation and determine whether the coefficient is greater than zero; if yes, go to step S215; if not, go to step S216.

Step S215: A short circuit of a single battery occurs and an alarm message is output.

Step S216: no single battery short circuit occurs, and no alarm information is output.

It should be pointed out that although the various steps are described in a specific sequence in the above embodiments, those skilled in the art can understand that in order to achieve the effects of the present invention, different steps do not have to be executed in this order. They can be executed simultaneously (in parallel) or in other sequences, and these changes are all within the protection scope of the present invention.

Referring to FIG. 3, FIG. 3 is a schematic diagram of the main structure of a short-circuit monitoring system for a single cell in a power battery according to an embodiment of the present invention. As shown in FIG. 3, the short-circuit monitoring system of the single battery in the power battery in the embodiment of the present invention mainly includes a deviation degree calculation device 11 and a battery short-circuit judgment device 12. For the sake of simplification, although the processor and the memory are not shown in FIG. 3, those skilled in the art can understand that the short-circuit monitoring system of the single battery in the power battery may be a part of the processor and/or the memory. For example, in some embodiments, one or more modules in the deviation degree calculation device 11 and the battery short-circuit determination device 12 may be a part of the processor. In some embodiments, these modules may respectively correspond to a part of electronic circuits in the processor for signal or data processing, and may also correspond to related program codes stored in a computer-readable medium (such as a memory). In some embodiments, one or more of the deviation degree calculating device 11 and the battery short-circuit judging device 12 may be combined into one module. In some embodiments, the deviation degree calculation device 11 may be configured to obtain the respective cell voltages of each cell in the power battery received within a certain period of time, and calculate the respective cell voltages of each cell within the certain period of time. The deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received. The battery short-circuit judging device 12 may be configured to judge whether the power battery has a single-cell short-circuit according to the respective deviation degree of each cell voltage; if so, output an alarm message. In an embodiment, the description of the specific realized function can refer to the description of step S101 to step S104.

In an embodiment, the deviation degree calculation device 11 may include a first deviation degree calculation module, and in this embodiment, the first deviation degree calculation module may be configured to perform the following operations:

Taking the preset battery short-circuit monitoring moment as the starting point of time, obtain the first cell corresponding to each single cell in the power battery received within the preset first time period after the preset battery short-circuit monitoring moment For voltage, the first deviation degree of each first cell voltage corresponding to the overall distribution of all first cell voltages is calculated respectively. In an embodiment, for the description of the specific realized functions, refer to the description in step S103.

In an embodiment, the battery short-circuit judgment device 12 may include a first short-circuit judgment module, and in this embodiment, the first short-circuit judgment module may be configured to perform the following operations:

It is determined whether the first deviation degrees corresponding to all the first cell voltages are less than or equal to the preset deviation degree threshold; if so, it is determined that no single cell short circuit has occurred in the power battery. In an embodiment, for the description of the specific realized functions, refer to the description in step S103.

In one embodiment, the deviation degree calculation device 11 may include a second deviation degree calculation module. In this embodiment, the battery short-circuit determination device 12 may include a second short-circuit determination module.

The second degree of deviation calculation module may be configured to use the preset battery short-circuit monitoring time as a time starting point to obtain the power batteries received in the preset second time period before the preset battery short-circuit monitoring time The second cell voltage corresponding to each single battery is calculated separately, and the second deviation degree of each second cell voltage corresponding to the overall distribution of all second cell voltages is calculated respectively; wherein, the second duration is preset Greater than the preset first duration. The second short circuit determination module may be configured to, when the first short circuit determination module determines that the first deviation degree corresponding to a certain first cell voltage is greater than a preset deviation degree threshold, according to the first deviation degree and the second deviation degree, Determine whether the power battery has a short-circuit of the single battery. In an embodiment, for the description of the specific realized functions, refer to the description in step S103.

Further, in one embodiment, the second short-circuit judgment module may be configured to perform the following operations: arrange the second deviation degree and the first deviation degree in the order of the cell voltage receiving time from first to last to obtain a deviation degree array; Perform linear regression calculation on the deviation degree in the deviation degree array to obtain the linear regression curve equation and linear fit; determine whether the linear fit is greater than the preset first fit threshold; if so, obtain it according to the linear regression curve equation The slope value of the corresponding linear regression curve; it is judged whether the slope value is greater than the preset slope threshold; if it is, it is judged that the power battery has a single battery short circuit. In an embodiment, for the description of the specific realized functions, refer to the description in step S103.

Further, in one embodiment, the second short-circuit judgment module is configured to perform the following operations: if the linear fit is less than or equal to the preset first fit threshold, perform a polynomial simulation on the deviation in the deviation array. Calculate together to obtain the second-order polynomial fitting curve equation and the polynomial fitting degree; determine whether the polynomial fitting degree is greater than the preset second-degree-of-fit threshold; if so, obtain the second-order term corresponding to the second-order polynomial fitting curve equation Determine whether the coefficient corresponding to the second-order item is greater than zero; if it is, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit. In an embodiment, for the description of the specific realized functions, refer to the description in step S103.

In one embodiment, the deviation degree calculation device 11 may be configured to execute the method shown in formula (1) to calculate the deviation degree of each cell voltage relative to the overall distribution of all cell voltages received. In an embodiment, for the description of the specific realized functions, refer to the description in step S102.

In an embodiment, the deviation degree calculation device 12 may be configured to perform the following operations:

Acquiring each current data of the power battery received within the certain period of time;

Arrange the working currents according to the current receiving time from first to last to obtain the working current array, and calculate the difference of the working currents in the working current array to obtain the respective difference of each working current; obtain the difference greater than the preset difference threshold The working current and the data receiving time corresponding to the working current; the corresponding cell voltage of each cell received within a certain time range before and after the data receiving time within the certain period of time is obtained and deleted, and then according to the remaining The cell voltage execution step of "respectively calculate the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time". In an embodiment, for the description of the specific realized functions, refer to the description in step S102.

The above-mentioned short-circuit monitoring system for single cells in power batteries is used to implement the embodiment of the short-circuit monitoring method for single cells in power batteries shown in FIG. Those skilled in the art can clearly understand that, for the convenience and concise description, the specific working process and related instructions of the short-circuit monitoring system of the single battery in the power battery can refer to the short-circuit monitoring method of the single battery in the power battery. The content described in the embodiment will not be repeated here.

Based on the foregoing method embodiment, the present invention also provides a storage device embodiment. In the storage device embodiment, the storage device stores a plurality of program codes, and the program codes are adapted to be loaded and run by the processor to execute the short-circuit monitoring method of the single battery in the power battery of the foregoing method embodiment. For ease of description, only the parts related to the embodiment of the present invention are shown. For specific technical details that are not disclosed, please refer to the method part of the embodiment of the present invention.

Based on the foregoing method embodiment, the present invention also provides an embodiment of a control device. In an embodiment of the control device, the device includes a processor and a storage device, and the storage device stores a plurality of program codes, and the program codes are suitable for being loaded and run by the processor to execute the single battery in the power battery of the foregoing method embodiment. Short-circuit monitoring method. For ease of description, only the parts related to the embodiment of the present invention are shown. For specific technical details that are not disclosed, please refer to the method part of the embodiment of the present invention.

Those skilled in the art can understand that all or part of the process in the method of the above-mentioned embodiment of the present invention can also be completed by instructing relevant hardware through a computer program, and the computer program can be stored in a computer readable In the storage medium, when the computer program is executed by the processor, the steps of the foregoing method embodiments can be implemented. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file, or some intermediate forms. The computer-readable medium may include: any entity or device, medium, portable disk, portable hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, and electronic carrier that can carry the computer program code. Signals, telecommunications signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or deleted according to the requirements of the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to the legislation and patent practice, the computer-readable medium Does not include electrical carrier signals and telecommunication signals.

Further, it should be understood that since the setting of each module is only to illustrate the functional units of the system of the present invention, the physical devices corresponding to these modules may be the processor itself, or a part of the software in the processor, a part of the hardware, or the software. Part of the combination with hardware. Therefore, the number of modules in the figure is only schematic.

Those skilled in the art can understand that each module in the system can be adaptively split or merged. Such splitting or merging of specific modules will not cause the technical solution to deviate from the principle of the present invention. Therefore, the technical solutions after splitting or merging will fall within the protection scope of the present invention.

The short-circuit monitoring method of the single battery in the power battery of the embodiment of the present invention receives and stores the corresponding single voltage of each single battery in each power battery sent by the battery management system in the electric vehicle, and extracts the voltage within a certain period of time. The corresponding cell voltage of each cell in the power battery is calculated, and the deviation of each cell voltage corresponding to the overall distribution of all cell voltages received during this period of time is calculated, and then according to these deviations Determine whether the power battery has a single battery short circuit and output an alarm message. The embodiment of the present invention analyzes whether the power battery is short-circuited according to the long-term and large number of single cell voltages of the power battery under various conditions such as low-current charging, high-current charging, electric vehicle static, and electric vehicle operation. The accuracy of power battery short-circuit monitoring overcomes the problem that the prior art cannot monitor whether the power battery has a single battery short circuit during high-current charging and electric vehicle operation, which reduces the accuracy of the monitoring result.

So far, the technical solution of the present invention has been described in conjunction with an embodiment shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

11: Deviation degree calculation device 12: Battery short circuit judgment device 21: Electric cars 22: background server

The specific embodiments of the present invention are described below with reference to the accompanying drawings, in which: Fig. 1 is a schematic flow chart of main steps of a method for short-circuit monitoring of a single cell in a power battery according to an embodiment of the present invention. 2 is a schematic flow chart of the main steps of a method for short-circuit monitoring of single cells in a power battery according to another embodiment of the present invention. 3 is a schematic diagram of the main structure of a short-circuit monitoring system for a single cell in a power battery according to an embodiment of the present invention. Figure 4 is a schematic diagram of an application scenario of the present invention.

Claims (18)

A method for short-circuit monitoring of a single cell in a power battery includes: Obtain the corresponding cell voltage of each cell in the power battery received within a certain period of time, and calculate the corresponding cell voltage of each cell within the certain period of time relative to all the cell voltages received The deviation of the overall distribution; According to the deviation degree corresponding to each cell voltage, it is determined whether the power battery has a cell short circuit; if it is, an alarm message is output. The method for short-circuit monitoring of a single cell in a power battery according to claim 1, wherein, "get the corresponding cell voltage of each single cell in the power battery received within a certain period of time, and calculate it in the The step of "the deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within a certain period of time" specifically includes: Taking the preset battery short-circuit monitoring moment as the starting point of time, obtain the first corresponding first battery of each single cell in the power battery received within the preset first time period after the preset battery short-circuit monitoring moment. For cell voltages, the first degree of deviation of each first cell voltage corresponding to the overall distribution of all first cell voltages is calculated respectively. The method for short-circuit monitoring of a single battery in a power battery according to claim 2, wherein the step of "determining whether the power battery has a single battery short circuit according to the deviation degree corresponding to each single cell voltage" is specific include: It is determined whether the first deviation degrees corresponding to all the first cell voltages are less than or equal to the preset deviation degree threshold; if so, it is determined that no single cell short circuit has occurred in the power battery. The method for short-circuit monitoring of a single battery in a power battery according to claim 3, wherein the step of "determining whether the power battery has a single battery short circuit according to the deviation degree corresponding to each of the voltages of each single battery" is further include: When the first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, the preset battery short-circuit monitoring time is used as the time starting point to obtain the preset battery short-circuit monitoring time The second cell voltage corresponding to each cell in the power battery received within the preset second time period is calculated, and the corresponding second cell voltage of each second cell voltage is calculated with respect to all the second cell voltages. The second degree of deviation of the overall voltage distribution; According to the first degree of deviation and the second degree of deviation, judging whether the power battery has a single battery short circuit; Wherein, the preset second duration is greater than the preset first duration. The method for short-circuit monitoring of a single battery in a power battery according to claim 4, wherein the step of "determining whether the power battery has a single battery short-circuit based on the first degree of deviation and the second degree of deviation" specifically includes : Arranging the second degree of deviation and the first degree of deviation in the order of the cell voltage receiving time from first to last to obtain an array of deviation degrees; Perform linear regression calculation on the deviation degree in the deviation degree array to obtain a linear regression curve equation and a linear fit degree; Determine whether the linear fit is greater than the preset first fit threshold; if so, obtain the slope value of the corresponding linear regression curve according to the linear regression curve equation; Determine whether the slope value is greater than a preset slope threshold; if it is, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit. The method for short-circuit monitoring of a single cell in a power battery according to claim 5, which further includes: If the linear fit is less than or equal to the preset first fit threshold, perform polynomial fitting calculation on the deviation in the deviation array to obtain the second-order polynomial fitting curve equation and the polynomial fit threshold ； Judging whether the polynomial fit degree is greater than a preset second degree of fit threshold; If the degree of fit of the polynomial is greater than the preset second degree of fit threshold, obtain the coefficient corresponding to the second-order term in the second-order polynomial fitting curve equation and determine whether the coefficient is greater than zero; The power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit; If the polynomial degree of fit is less than or equal to the preset second degree of fit threshold, it is determined that the power battery does not have a single battery short circuit. The method for short-circuit monitoring of a single cell in a power battery according to any one of claims 1 to 6, wherein “respectively calculate the corresponding value of each cell voltage within the certain period of time relative to all received The step of "the degree of deviation of the overall distribution of cell voltage" specifically includes: Calculating the degree of deviation according to the method shown in the following formula:

Among them, the

Is the cell voltage of the j-th cell in the power battery received at the i-th time within the certain period of time, the

Is the cell voltage

Corresponding degree of deviation, the

Is the average value of all cell voltages received at the i-th time within the certain period of time, the

It is the standard deviation of all cell voltages received at the i-th time within the certain period of time. The method for short-circuit monitoring of a single battery in a power battery according to any one of claims 1 to 6, wherein, in "respectively calculating the corresponding voltage of each single cell within the certain period of time, relative to the received Before the step of "the degree of deviation of the overall distribution of the voltages of all cells", the short-circuit monitoring method of the single cells in the power battery further includes: Acquiring each working current of the power battery received within the certain period of time; Arranging the working currents in the order of current receiving time from first to last to obtain a working current array, and performing differential calculation on the working currents in the working current array to obtain the respective difference corresponding to each working current; Acquiring the working current whose difference is greater than a preset difference threshold and the data receiving time corresponding to the working current; Obtain and delete the corresponding cell voltage of each cell received within a certain period of time before and after the data receiving time within the certain period of time, and then execute the step "calculated separately according to the remaining cell voltages" The deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time". A short-circuit monitoring system for a single battery in a power battery includes: A deviation degree calculation device, which is configured to obtain the corresponding cell voltage of each cell in the power battery received within a certain period of time, and respectively calculate the corresponding cell voltage of each cell in the certain period of time The deviation degree from the overall distribution of all cell voltages received; A battery short circuit judging device, which is configured to judge whether the power battery has a single battery short circuit according to the deviation degree corresponding to each of the individual cell voltages; if so, output an alarm message. The short-circuit monitoring system for a single battery in a power battery according to claim 9, wherein the deviation degree calculation device includes a first deviation degree calculation module, and the first deviation degree calculation module is configured to perform the following operations: Taking a preset battery short-circuit monitoring moment as the starting point of time, obtain the corresponding corresponding to each single cell in the power battery received within a preset first time period after the preset battery short-circuit monitoring moment For the first cell voltage, the first deviation degree of each first cell voltage corresponding to the overall distribution of all the first cell voltages is calculated respectively. The short-circuit monitoring system for a single battery in a power battery according to claim 10, wherein the battery short-circuit judging device includes a first short-circuit judging module, and the first short-circuit judging module is configured to perform the following operations: It is determined whether the first deviation degrees corresponding to all the first cell voltages are less than or equal to the preset deviation degree threshold; if so, it is determined that no single cell short circuit has occurred in the power battery. The short-circuit monitoring system of a single battery in a power battery according to claim 11, wherein the deviation degree calculation device includes a second deviation degree calculation module, and the battery short-circuit judgment device includes a second short-circuit judgment module; The second degree of deviation calculation module is configured to use the preset battery short-circuit monitoring time as a time start point to obtain all the data received within a preset second time period before the preset battery short-circuit monitoring time. According to the second cell voltage corresponding to each single cell in the power battery, the second deviation degree corresponding to each second cell voltage with respect to the overall distribution of all second cell voltages is calculated respectively; wherein, the The preset second duration is greater than the preset first duration; The second short-circuit judgment module is configured to, when the first short-circuit judgment module judges that a first deviation degree corresponding to a certain first cell voltage is greater than the preset deviation degree threshold, according to the first deviation And the second deviation degree to determine whether the power battery has a single battery short circuit. The short-circuit monitoring system for single cells in a power battery according to claim 12, wherein the second short-circuit judgment module is configured to perform the following operations: Arranging the second degree of deviation and the first degree of deviation in the order of the cell voltage receiving time from first to last to obtain an array of deviation degrees; Perform linear regression calculation on the deviation degree in the deviation degree array to obtain a linear regression curve equation and a linear fit degree; Determine whether the linear fit is greater than the preset first fit threshold; if so, obtain the slope value of the corresponding linear regression curve according to the linear regression curve equation; Determine whether the slope value is greater than a preset slope threshold; if it is, it is determined that the power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit. The short-circuit monitoring system for a single cell in a power battery according to claim 13, wherein the second short-circuit judgment module is configured to perform the following operations: If the linear fit is less than or equal to the preset first fit threshold, perform polynomial fitting calculation on the deviation in the deviation array to obtain the second-order polynomial fitting curve equation and the polynomial fit threshold ； Judging whether the polynomial fit degree is greater than a preset second degree of fit threshold; If the degree of fit of the polynomial is greater than the preset second degree of fit threshold, obtain the coefficient corresponding to the second-order term in the second-order polynomial fitting curve equation and determine whether the coefficient is greater than zero; The power battery has a single battery short circuit; if not, it is determined that the power battery does not have a single battery short circuit; If the polynomial degree of fit is less than or equal to the preset second degree of fit threshold, it is determined that the power battery does not have a single battery short circuit. The short circuit monitoring system of a single cell in a power battery according to any one of claims 9 to 14, wherein the deviation degree calculation device is configured to perform the following operations: calculate the deviation according to the method shown in the following formula Spend:

Among them, the

Is the cell voltage of the j-th cell in the power battery received at the i-th time within the certain period of time, the

Is the cell voltage

Corresponding degree of deviation, the

Is the average value of all cell voltages received at the i-th time within the certain period of time, the

It is the standard deviation of all cell voltages received at the i-th time within the certain period of time. The short-circuit monitoring system of a single cell in a power battery according to any one of claims 9 to 14, wherein the deviation degree calculation device is configured to perform the following operations: Acquiring each working current of the power battery received within the certain period of time; Arranging the working currents in the order of current receiving time from first to last to obtain a working current array, and performing differential calculation on the working currents in the working current array to obtain the respective difference corresponding to each working current; Acquiring a working current whose difference is greater than a preset difference threshold and acquiring a data receiving time corresponding to the working current; Obtain and delete the corresponding cell voltage of each cell received within a certain period of time before and after the data receiving time within the certain period of time, and then execute the step "calculated separately according to the remaining cell voltages" The deviation degree of each cell voltage corresponding to the overall distribution of all cell voltages received within the certain period of time". A storage device, wherein multiple pieces of program codes are stored, wherein the program codes are adapted to be loaded and run by a processor to execute the short-circuit of a single battery in a power battery according to any one of request items 1 to 8. Monitoring method. A control device, comprising a processor and a storage device, the storage device is adapted to store a plurality of program codes, characterized in that the program code is adapted to be loaded and run by the processor to execute any of the request items 1 to 8. A method for short-circuit monitoring of single cells in power batteries as described in one item.

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