CN114675190A

CN114675190A - Battery safety assessment method and device and electronic equipment

Info

Publication number: CN114675190A
Application number: CN202210403158.8A
Authority: CN
Inventors: 田培根; 肖曦; 于璐; 张辉
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-04-18
Filing date: 2022-04-18
Publication date: 2022-06-28

Abstract

The invention provides a method and a device for evaluating battery safety and electronic equipment, wherein the method comprises the following steps: acquiring single indexes of a plurality of single batteries in the battery module, wherein the single indexes comprise voltage differences and temperatures of the single batteries; determining the monomer score of each battery monomer according to the monomer index of each battery monomer; determining module indexes of a plurality of battery modules in the battery system, wherein the module indexes comprise the charge state range of the battery modules and the monomer scoring key value of a single battery; and determining the module score of each battery module according to the module index of each battery module. According to the technical scheme provided by the embodiment of the invention, the health degree of the battery can be evaluated from two levels of the battery monomer and the battery module, the safety of the battery can be more accurately evaluated, whether the battery monomer is abnormal or not is comprehensively determined from two dimensions of electrical parameters and temperature parameters, and the accuracy of evaluation can be improved; and the online monitoring of the battery can be realized.

Description

Battery safety assessment method and device and electronic equipment

Technical Field

The invention relates to the technical field of battery evaluation, in particular to a method and a device for battery safety evaluation, electronic equipment and a computer-readable storage medium.

Background

At present, the retired power battery of the electric automobile is low in recycling price, meets the requirements of an energy storage power station, is beneficial to reducing the cost of power energy storage equipment, and can be widely popularized in the field of power system energy storage. Because the battery is used for a long time by the electric automobile in a gradient way, potential safety hazards such as dendritic crystal growth, impedance increase, internal electrochemical structure change and the like exist. Safety becomes a key influence factor for large-scale construction and popularization of a power battery echelon utilization energy storage system, and the safety problem is more and more emphasized.

Because the battery is used for echelon aging, the safety performance is weaker than a brand-new battery, and in the actual operation of the battery, the overcharge and the overdischarge of the battery monomers generate heat between the battery modules unevenly and the inconsistency can cause the occurrence of safety risks.

Most of the existing safety early warning methods for Battery systems (energy storage systems) are protection measures for Battery modules, such as BMS (Battery management system), Battery thermal management system, etc., but at the level of Battery cells in the energy storage system, monitoring and evaluation on the safety performance of the Battery are lacking.

Disclosure of Invention

In order to solve the existing technical problem, embodiments of the present invention provide a method and an apparatus for battery safety assessment, an electronic device, and a computer-readable storage medium.

In a first aspect, an embodiment of the present invention provides a method for evaluating battery safety, including:

acquiring single indexes of a plurality of single batteries in a battery module, wherein the single indexes comprise voltage differences and temperatures of the single batteries, and the voltage differences of the single batteries are differences between current voltages and standard voltages of the single batteries;

determining a cell score of each battery cell according to the cell index of each battery cell, wherein the cell score is used for representing the health degree of the battery cell;

determining module indexes of a plurality of battery modules in a battery system, wherein the module indexes comprise the charge state range of the battery modules and the monomer score key values of a plurality of single batteries in the battery modules;

and determining a module score of each battery module according to the module index of each battery module, wherein the module score is used for expressing the health degree of the battery module.

In a second aspect, an embodiment of the present invention further provides an apparatus for evaluating battery safety, including:

the first obtaining module is used for obtaining single indexes of a plurality of single batteries in a battery module, wherein the single indexes comprise voltage differences and temperatures of the single batteries, and the voltage differences of the single batteries are differences between current voltages and standard voltages of the single batteries;

the first scoring module is used for determining a single score of each battery cell according to a single index of each battery cell, and the single score is used for representing the health degree of the battery cells;

the second acquisition module is used for determining module indexes of a plurality of battery modules in a battery system, wherein the module indexes comprise the charge state ranges of the battery modules and the single scoring key values of a plurality of single batteries in the battery modules;

and the second grading module is used for determining the module grade of each battery module according to the module index of each battery module, and the module grade is used for expressing the health degree of the battery module.

In a third aspect, an embodiment of the present invention provides an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored on the memory and executable on the processor, where the transceiver, the memory, and the processor are connected via the bus, and the computer program, when executed by the processor, implements the steps in the method for battery safety assessment described in any one of the above.

In a fourth aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps in the method for battery safety assessment described in any one of the above.

According to the method, the device, the electronic equipment and the computer readable storage medium for evaluating the safety of the battery, provided by the embodiment of the invention, the health degree of the battery monomer is firstly determined, the battery is monitored and evaluated from the battery monomer layer, then the health degree of the battery module is further determined on the basis of the health degree of the battery monomer, the health degree of the battery can be evaluated from two levels of the battery monomer and the battery module, and the safety of the battery can be evaluated more accurately. The voltage difference and the temperature of the single battery are collected, whether the single battery is abnormal or not is comprehensively determined from two dimensions of the electrical parameter and the temperature parameter, and the accuracy of evaluation can be improved; and moreover, the voltage difference, the temperature and the charge state of the battery monomer can be collected in real time, the health degree of the battery monomer and the health degree of the battery module can be determined in real time, the online monitoring of the battery is realized, and a reliable basis can be provided for the safe operation of the battery.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present invention, the drawings required to be used in the embodiments or the background art of the present invention will be described below.

FIG. 1 is a flow chart illustrating a method for battery safety assessment provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an apparatus for battery safety assessment according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an electronic device for performing a method for battery safety evaluation according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 shows a flowchart of a method for battery safety evaluation according to an embodiment of the present invention. As shown in fig. 1, the method includes:

step 101: the method comprises the steps of obtaining single indexes of a plurality of single batteries in the battery module, wherein the single indexes comprise voltage differences and temperatures of the single batteries, and the voltage differences of the single batteries are difference values between current voltages and standard voltages of the single batteries.

In the embodiment of the invention, for the battery system to be evaluated, for example, the battery is utilized in the echelon to be evaluated; the battery system generally comprises a plurality of battery modules, each battery module comprises a plurality of battery cells, and at least part of the battery cells are used as single battery cells to perform safety evaluation by taking the single battery cells as units. For each battery cell, the voltage difference and the temperature of the battery cell can be collected, and both the voltage difference and the temperature are indexes which can be used for evaluating the safety of the battery cell, and the embodiment is called as a cell index. For example, the current voltage and the temperature of each battery cell may be collected in real time, so that a difference value between the current voltage and the standard voltage, that is, a voltage difference may be determined, and a cell index including the voltage difference and the temperature of each battery cell may be obtained in real time.

For example, a curve between a state of charge (SOC) and a voltage of the battery cell may be preset, and a voltage corresponding to the current SOC in the curve may be used as the current desired voltage. Alternatively, the average value of the current voltages of all the battery cells in the battery module may be used as the standard voltage.

When the existing battery system runs safely, the safety of the existing battery system is often judged based on the abnormity of single or single parameters, and if the temperature rise rate of the battery is greater than 1 ℃/s (lasting for more than 3 s) and the temperature of the battery is greater than 200 ℃, the battery is considered to be abnormal. However, the safety of the battery in the energy storage is determined by different levels of multiple factors such as electricity, heat and the like, the battery has different performance characteristics, and single-factor evaluation cannot reliably and comprehensively express the safety performance of the battery in operation. According to the embodiment of the invention, the voltage difference and the temperature of the single battery are acquired, whether the single battery is abnormal or not is comprehensively determined from two dimensions of the electrical parameter and the temperature parameter, and the accuracy of evaluation can be improved.

Optionally, the state of the battery module mainly includes a charging/discharging state (specifically, a charging state or a discharging state) and a static state (i.e., a state when the battery module does not operate). When the battery module is at rest, the collected current voltage of the battery cell is an Open Circuit Voltage (OCV) of the battery cell, that is, a potential difference between an anode and a cathode of the battery cell in an Open circuit state. In the case of charging and discharging the battery module, the current voltage of the battery cell is the real-time voltage of the battery cell, such as the charging voltage or the discharging voltage of the battery cell.

Step 102: and determining the monomer score of each battery monomer according to the monomer index of each battery monomer, wherein the monomer score is used for expressing the health degree of the battery monomer.

In the embodiment of the invention, after the monomer index of each battery monomer in the battery module is determined, the score capable of evaluating the health degree of the battery monomer, namely the monomer score, is determined based on the monomer index of the battery monomer; each cell corresponds to a cell score. The single body score of the battery is related to the voltage difference and the temperature of the battery, and the voltage difference and the temperature change of the battery can affect the single body score; for example, the higher the temperature of the battery cell, the more likely there is a safety problem, and the worse its health, the lower the cell score.

Step 103: the method comprises the steps of determining module indexes of a plurality of battery modules in the battery system, wherein the module indexes comprise the charge state range of the battery modules and the single scoring key values of a plurality of single batteries in the battery modules.

In the embodiment of the invention, after the monomer scores of a plurality of battery monomers in the battery module are determined, the module index of the battery module can be determined based on the monomer scores, namely, the monomer score key value is used as the module index of the battery module. The cell score key value is a value between the cell scores of the plurality of battery cells, for example, the cell score key value may be an average value, a median value, and the like of the cell scores of the plurality of battery cells; alternatively, the cell score key value may be a minimum value of the cell scores of the plurality of battery cells. In addition, the method and the device also determine the state of charge (SOC) of each battery cell in the battery module, and represent the residual capacity of the battery cell by the SOC; based on the state of charge of a plurality of battery monomers in the battery moduleDetermining the SOC range of the battery module by the maximum value of the SOC value, and taking the SOC range as a class of module indexes of the battery module; wherein the state of charge range α_socTo the maximum value of the state of charge SOC at the present moment_maxAnd state of charge minimum SOC_minThe difference between them, i.e. alpha_soc＝SOC_max-SOC_min. In general, the state of charge range remains unchanged when the performance of each of the plurality of cells is unchanged.

Optionally, the module index may further include: voltage statistics and/or temperature statistics of a plurality of cells in a battery module. The voltage statistic comprises at least one of a mean value of voltage differences of the plurality of battery cells, a standard deviation of current voltage and a variance of the current voltage; the temperature statistics include at least one of a mean, a standard deviation, and a variance of the temperatures of the plurality of battery cells. For example, the voltage difference average value and the temperature average value of all the battery cells in the battery module can be used as the module-like index. If the standard voltage is the average value of the current voltages of all the battery cells in the battery module, the average value of the voltage differences of the plurality of battery cells is equivalent to the variance of the current voltages.

Step 104: and determining the module grade of each battery module according to the module index of each battery module, wherein the module grade is used for expressing the health degree of the battery module.

In the embodiment of the present invention, similar to the step 102, after determining the various module indexes of each battery module, a score that can evaluate the health degree of the battery module, that is, a module score, is determined based on the various module indexes; each battery module corresponds to one module score. The lower the module score, the worse the health of the battery module, the more likely it is to have safety issues.

According to the method for evaluating the safety of the battery, provided by the embodiment of the invention, the health degree of the single battery is firstly determined, the battery is monitored and evaluated from the single battery layer, then the health degree of the battery module is further determined on the basis of the health degree of the single battery, the health degree of the battery can be evaluated from two levels of the single battery and the battery module, and the safety of the battery can be evaluated more accurately. The voltage difference and the temperature of the single battery are collected, whether the single battery is abnormal or not is comprehensively determined from two dimensions of the electrical parameter and the temperature parameter, and the accuracy of evaluation can be improved; and moreover, the voltage difference, the temperature and the charge state of the battery monomer can be collected in real time, the health degree of the battery monomer and the health degree of the battery module can be determined in real time, the online monitoring of the battery is realized, and a reliable basis can be provided for the safe operation of the battery.

Alternatively, the step 102 of "determining the cell score of each battery cell according to the cell index of each battery cell" includes the following step a1, and/or the step 104 of "determining the module score of each battery module according to the module index of each battery module" includes the following step B1:

step A1: and taking the single battery as a target object, taking the single index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as a corresponding single score.

Step B1: and taking the battery module as a target object, taking the module index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as a corresponding module score.

The step a1 or the step B1 of "determining a target score of the target object based on the target index" includes:

step C1: the weight of each type of target index is determined.

Step C2: and determining the target score of the target object by weighting each type of target index.

In the embodiment of the invention, in the process of determining the cell score or the module score, the corresponding index can be used as a target index, the corresponding object (the battery cell or the battery module) can be used as a target object, and the corresponding target score, namely the cell score or the module score, is determined based on the steps C1-C2. Specifically, in the process of determining the cell score based on steps C1-C2, the weight of each type of cell indicator, for example, the weight of the voltage difference and the weight of the temperature, is determined, and then the cell indicator of each type is weighted based on the weights, and the weighted result is regarded as the cell score. Alternatively, in the process of determining the module score in steps C1-C2, the weight of each type of module index, for example, the weight of the state of charge range and the weight of the key value of the individual score, is determined, and then the module index of each type is weighted based on the weights, and the weighted result is used as the module score.

Alternatively, the weight of each type of target index may be set to be the same, or the weight of each type of target index may be set based on experience. Alternatively, in the embodiment of the present invention, the weight of each type of target indicator is determined by using an entropy value, and the step C1 "determining the weight of each type of target indicator" includes steps C11-C12:

step C11: constructing a decision matrix Q, wherein the element Q of the ith row and the jth column in the decision matrix Q_ijA value of a jth class target index representing an ith target object; i is 1,2, …, m, j is 1,2, …, n, m represents the number of target objects, and n represents the number of types of target indexes.

In the embodiment of the present invention, in the process of determining the target scores of a plurality of target objects, each target object relates to a plurality of types of target indexes, so that the decision matrix Q is set in this embodiment. Specifically, if it is required to determine target scores of m target objects, each target object relates to n target indexes, an m × n decision matrix Q may be established, where one form of the decision matrix Q is as follows:

wherein, the element Q of the ith row and the jth column in the decision matrix Q_ijThe value of the jth class target index representing the ith target object. For example, in the process of determining the cell score, if the battery module includes 10 battery cells and both the voltage difference and the temperature indexes are involved, m is 10, and n is 2; wherein, the 1 st column in the decision matrix Q may represent the voltage difference of 10 battery cells, and the 2 nd column represents 10 battery cellsThe temperature of the body. Or, for example, in the process of determining the module score, if the four module indexes, i.e., the state of charge range of the battery module, the cell score key value, the standard deviation of the current voltage, and the temperature standard deviation, are all involved, n is 4.

Optionally, since different types of indexes are involved in the embodiment, and the measurement units of each type of index are not uniform, the embodiment of the present invention performs normalization processing on the acquired original value, that is, converts the original absolute value of the index into a relative value, thereby solving the problem of homogenization of various index values of different qualities. Specifically, the step C11 "constructing the decision matrix Q" may include:

step C111: normalizing the original value of the jth target index of the ith target object, and taking the normalized result as the element Q of the jth row and the jth column in the decision matrix Q_ij(ii) a And satisfies the following conditions:

wherein q is_ij' original value of j-th class target index representing ith target object, q_j' denotes an original value corresponding to the j-th class target index.

In the embodiment of the invention, the original value of each type of target index of each target object can be determined in an acquisition manner, and the original value refers to an absolute value (not a relative value) which can be directly obtained in an acquisition manner. For each original value q by the above equation (2)_ij' normalization is performed to obtain the desired value q_ijThereby generating an m × n decision matrix Q. Wherein q is_j' denotes the original value corresponding to the j-th type target index, which contains m original values, max (q)_j') represents the maximum of the m original values corresponding to the j-th class target index, and accordingly min (q)_j') represents the minimum of the m original values for the j-th class of target indicators.

For example, the jth type target index (cell index) is temperature, and if the ith cell temperature is 40 ℃, the original value q is_ij' is 40 ℃. If maximum value of temperature60 ℃ and a minimum value of 20 ℃ based on the above formula (2), and after normalization, the value q of the indicator (i.e., temperature) of the j-th cell of the i-th cell_ij＝0.5。

Step C12: determining the weight of each class of target indexes according to the decision matrix Q, wherein the weight lambda of the jth class of target indexes_iSatisfies the following conditions:

wherein the content of the first and second substances,

in the embodiment of the invention, the specific gravity r of the ith target object under the jth type target index is determined_ijAnd the specific gravity r_ijSatisfies the following conditions:

determining entropy H of jth class target index_jAnd the entropy value H_jSatisfies the following conditions:

further, the weight lambda of the j-th target index can be determined_iAnd weight λ_iSatisfies the following conditions:

for each type of target indicator (i.e., j takes a different value, and j ═ 1,2, …, n), the weight of the corresponding target indicator can be determined based on equation (5) above, i.e., n weights can be determined.

Further alternatively, the weighting process may be performed in a conventional weighting manner; for example, for the ith target object, the values of the n target indexes are respectivelyq_i1、q_i2、…、q_inTarget score s of the ith target object_iCan be as follows:

this way the target score for each target object is determined independently, without taking into account the relevance between the target objects. In the embodiment of the invention, the optimal index and the worst index in each type of target index are used for weighting. Specifically, the step C2 "determining the target score of the target object by weighting each type of target index" includes steps C21-C22:

step C21: weighting the difference between the target index of the target object and the optimal index of the corresponding target index to determine the optimal distance d_i ⁺(ii) a Weighting the difference between the target index of the target object and the worst index of the target index of the corresponding class to determine the worst distance d_i ^-。

In the embodiment of the invention, the target index of the target object is not directly weighted, but the difference value between the target index and the corresponding optimal index and the difference value between the target index and the worst index are weighted. Specifically, the j-th type target index q for the ith target object_ijThe corresponding class target index is the jth class target index; if the optimal index of the jth class target index is C_j ⁺Then the target index q can be determined_ijAnd the optimum index C_j ⁺The difference between them is:

further, the difference corresponding to the n types of target indexes is weighted to obtain the optimal distance d which can represent the distance between the ith target object and the optimal index_i ⁺(ii) a The optimal distance d_i ⁺The smaller the number, the better the health of the ith target object.

Similarly, if the worst index of the j-th class target index is C_j ^-Then the target finger can be determinedMark q_ijWith the worst index C_j ^-The difference between them is:

further, the difference values corresponding to the n types of target indexes are weighted to obtain the distance between the ith target object and the worst index, namely the worst distance d_i ^-(ii) a Conversely, the worst distance d_i ^-The smaller the value, the worse the health of the ith target subject.

Optionally, the step C21 may specifically include steps C211 to C213:

step C211: constructing a decision matrix Q, wherein the element Q of the ith row and the jth column in the decision matrix Q_ijA value of a jth class target index representing an ith target object; i is 1,2, …, m, j is 1,2, …, n, m represents the number of target objects, and n represents the number of types of target indexes.

In the embodiment of the present invention, the same process as that in the step C11 above, the decision matrix Q may be constructed, and the construction process thereof may specifically refer to the step C111 above. For example, the embodiment of the present invention may construct a decision matrix Q, and perform step C12 based on the decision matrix Q to determine the weight λ of the target index_i(ii) a And step C21 (e.g., subsequent steps C212-C213) is performed based on the decision matrix Q to determine an optimal distance and an inferior distance.

Step C212: determining the optimal index and the worst index of each type of target index, and meeting the following conditions:

C_j ⁺＝{(maxq_ij|j∈J₁),(minq_ij|j∈J₂)}；

C_j ^-＝{(minq_ij|j∈J₁),(maxq_ij|j∈J₂)}；

wherein, C_j ⁺、C_j ^-Respectively representing the optimal index and the worst index of the jth class target index, J₁Represents a positive index set, J₂Representing a set of negative indicators.

The embodiment of the invention relates to m types of target indexes, each type of target index is different, and the influence on the health degree is different; in the embodiment of the invention, if the target index is larger and the health degree is higher (namely, the target score is higher), the target index is called as a positive index, namely, the larger the positive index is, the better the positive index is; conversely, if the target index is smaller, the degree of health is higher (i.e., the target score is higher), the target index is referred to as a "negative index", i.e., the smaller the negative index, the better. For example, for the module index "state of charge range" or "voltage standard deviation", etc., the smaller the value is, the better the value is, so it is a negative index; for the module index "monomer score key value", the larger the value, the better, so it is a positive index.

In the embodiment of the invention, the positive indexes of all classes form a positive index set J₁So that the negative indicators of a class form a negative indicator set J₂. For the J-th type target index, if it is a positive index, J belongs to J₁The optimal index C of the jth class target index_j ⁺Is maxq_ijThe worst index C_j ^-Is minq_ij(ii) a Conversely, if the J-th type target index is a negative index, i.e., J ∈ J₂The optimal index C of the jth class target index_j ⁺Is minq_ijThe worst index C_j ^-Is maxq_ij。

Step C213: determining an optimal distance d of a target object_i ⁺And the worst distance d_i ^-And satisfies:

alternatively, the first and second electrodes may be,

alternatively, the first and second electrodes may be,

step C22: according to the optimal distance d_i ⁺And the worst distance d_i ^-Determining a target score of the target object, the target score of the target object and the optimal distance d_i ⁺Has a negative correlation with the worst distance d_i ^-The two are in positive correlation.

In the embodiment of the present invention, as described above, the optimal distance d_i ⁺The smaller the value, the better the health of the ith target object is; conversely, the worst distance d_i ^-The smaller the value, the worse the health of the ith target subject. Thus, the target score of the ith target object is the optimal distance d_i ⁺The negative correlation relationship is formed between the target score and the worst distance d_i ^-The two are in positive correlation. For example, if the target score of the ith target object is s_iThen the target score s_iCan satisfy the following conditions:

alternatively, in step C212, regarding the temperature-related index, such as the temperature of the battery cell (cell index), the temperature average value of the battery module (module index), and the like, generally, the larger the temperature-related index is, the worse the health degree is, that is, the index may be used as a negative index. However, since the health of the battery is also affected when the temperature is low, that is, the temperature-related index is optimal at a certain value, the health is decreased above or below the optimal value; therefore, the embodiment of the present invention sets the optimum index having a fixed property for the index relating to the temperature, that is, the optimum index is fixed. For example, when the j-th type target index is an index related to temperature, the optimal index of the j-th type target index is set to a fixed value, and the optimal distance can be determined reasonably.

Further, in the case where the j-th type target index is a temperature-related index, the j-th type target index is set with a first worst index smaller than the optimum index and a large indexThe second worst index of the optimal index. And, a difference value Deltaq between the target index of the target object and the worst index of the j-th class target index_jAnd satisfies the following conditions:

wherein, c_1,j ^-、c_2,j ^-Respectively represent a first worst index, a second worst index, C_j ⁺And the optimal index represents the j-th type target index.

In the embodiment of the invention, the optimal index C is actively set for the j category target index related to the temperature_j ⁺The first worst index c_1,j ^-The second worst index c_2,j ^-And the three satisfy: c. C_1,j ^-＜C_j ⁺＜c_2,j ^-. For values q of different sizes_ijDetermining the difference between this value and the nearest worst indicator, i.e. when q is_ij＜C_j ⁺When is, Δ q_j＝|q_ij-c_1,j ^-L, |; when q is_ij＞C_j ⁺When is, Δ q_j＝|q_ij-c_2,j ^-L. For example, the first worst indicator c_1,j ^-Can be the minimum value of the j-th type target index, the second worst index c_2,j ^-May be the maximum value of the j-th class target index.

It should be noted that "setting the optimal index of the jth type target index to be a fixed value" in the embodiment of the present invention means that the optimal index of the jth type target index has a fixed attribute, and the optimal index is not limited to be absolutely unchanged. For example, if the optimum temperature of the battery cell is 25 ℃, the optimum index may be set to be a fixed 25 ℃; however, since embodiments of the present invention involve normalization, the normalized values may not be fixed (e.g., the normalized values are related to the current maximum and minimum temperatures), but this does not affect the normalized values to still have fixed properties.

Further alternatively, the step 102 of "determining the cell score of each battery cell according to the cell index of each battery cell" may include the following step a2, and/or the step 104 of "determining the module score of each battery module according to the module index of each battery module" may include the following step B2:

step A2: and when the current voltage of the battery cell is zero or the current voltage change rate exceeds a safety threshold value, setting the cell score of the battery cell as a minimum score.

Step B2: and setting the module score of the battery module as the minimum score when the cell score of at least one battery cell in the battery module is the minimum score.

In the embodiment of the invention, under normal conditions, the voltage value of the single battery cannot be zero, and the single battery has a certain charge-discharge rate, and the current voltage change rate of the single battery cannot be very large. If the voltage value of the battery cell is zero or the current voltage change rate exceeds the safety threshold (for example, a voltage drop occurs greatly), it indicates that the battery cell is abnormal, which may possibly affect the normal operation of the entire battery module or the battery system, and at this time, the cell score of the battery cell is set to the minimum score (for example, set to 0) to indicate that the health degree of the battery cell is very poor.

Similarly, if the health degree of a certain battery cell in the battery module is very poor, because a plurality of battery cells in the battery module are generally connected in series, a certain battery cell is abnormal, and the whole battery module has great inconsistency, thereby causing the charging and discharging abnormality of the battery module. Therefore, if there is a battery cell having a cell score of the minimum score in the battery module, the module score of the battery module is also set to the minimum score, for example, 0.

According to the method for evaluating the safety of the battery, provided by the embodiment of the invention, the health degree of the single battery is firstly determined, the battery is monitored and evaluated from the single battery layer, then the health degree of the battery module is further determined on the basis of the health degree of the single battery, the health degree of the battery can be evaluated from two levels of the single battery and the battery module, and the safety of the battery can be evaluated more accurately. The voltage difference and the temperature of the single battery are collected, whether the single battery is abnormal or not is comprehensively determined from two dimensions of the electrical parameter and the temperature parameter, and the accuracy of evaluation can be improved; and moreover, the voltage difference, the temperature and the charge state of the battery monomer can be collected in real time, the health degree of the battery monomer and the health degree of the battery module can be determined in real time, the online monitoring of the battery is realized, and a reliable basis can be provided for the safe operation of the battery. The weight is determined by utilizing the entropy value, so that the importance degree of each type of index can be more reliably determined; the target score of a certain target object can be determined integrally by using the difference value between the target index and the optimal index and the worst index for weighting processing, and combining with other target objects, so that the relevance among the target objects can be strengthened. And a fixed optimal index is set for the temperature index, so that the optimal distance can be reasonably determined, and further, a reasonable score is determined.

The method for evaluating the safety of the battery provided by the embodiment of the invention is described above in detail, and the method can also be implemented by a corresponding device.

Fig. 2 is a schematic structural diagram illustrating an apparatus for evaluating battery safety according to an embodiment of the present invention. As shown in fig. 2, the apparatus for battery safety evaluation includes:

the first obtaining module 21 is configured to obtain cell indexes of a plurality of cells in a battery module, where the cell indexes include voltage differences and temperatures of the cells, and the voltage differences of the cells are differences between current voltages and standard voltages of the cells;

the first scoring module 22 is configured to determine a cell score of each battery cell according to a cell index of each battery cell, where the cell score is used to indicate a health degree of the battery cell;

the second obtaining module 23 is configured to determine module indexes of a plurality of battery modules in a battery system, where the module indexes include a state of charge range of the battery module and a cell score key value of a plurality of battery cells in the battery module;

and the second grading module 24 is configured to determine a module grade of each battery module according to the module index of each battery module, where the module grade is used to indicate the health degree of the battery module.

In a possible implementation manner, the module index further includes a voltage statistic and/or a temperature statistic of a plurality of battery cells in the battery module;

the voltage statistic comprises at least one of a mean value of voltage differences of a plurality of battery cells, a standard deviation of current voltage and a variance of current voltage;

the temperature statistic includes at least one of a mean, a standard deviation, and a variance of the temperatures of the plurality of battery cells.

In one possible implementation manner, the determining, by the first scoring module 22, the cell score of each battery cell according to the cell index of each battery cell includes: taking the single battery as a target object, taking the single index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as the corresponding single score;

and/or

The second scoring module 24 determines module scoring of each battery module according to the module index of each battery module, including: taking the battery module as a target object, taking the module index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as the corresponding module score;

wherein the determining a target score of the target object based on the target index comprises:

determining the weight of each type of target index;

and determining the target score of the target object by weighting each type of the target indexes.

In a possible implementation manner, the determining the weight of each type of the target indicator includes:

constructing a decision matrix Q, wherein an element Q in the ith row and the jth column in the decision matrix Q_ijA value of a jth class target index representing an ith target object; i is 1,2, …, m, j is 1,2, …, n, m represents the number of the target objects, n represents the number of the target indexes;

determining the weight of each class of target indexes according to the decision matrix Q, wherein the weight lambda of the jth class of target indexes_iSatisfies the following conditions:

wherein the content of the first and second substances,

in a possible implementation manner, the determining the target score of the target object by weighting each type of the target index includes:

weighting the difference value between the target index of the target object and the optimal index of the target index of the corresponding class to determine the optimal distance d_i ⁺(ii) a Weighting the difference value between the target index of the target object and the worst index of the target index of the corresponding class to determine the worst distance d_i ^-；

According to the optimal distance d_i ⁺And the worst distance d_i ^-Determining a target score of the target object, the target score of the target object and the optimal distance d_i ⁺Is in negative correlation with the worst distance d_i ^-The two are in positive correlation.

In a possible implementation manner, the difference between the target index of the target object and the optimal index of the target index of the corresponding class is weighted to determine the optimal distance d_i ⁺(ii) a Target indexes of the target objects and the corresponding target indexesThe difference between the worst indexes is weighted to determine the worst distance d_i ^-The method comprises the following steps:

determining the optimal index and the worst index of each type of target index, and meeting the following conditions:

C_j ⁺＝{(maxq_ij|j∈J₁),(minq_ij|j∈J₂)}；

C_j ^-＝{(minq_ij|j∈J₁),(maxq_ij|j∈J₂)}；

wherein, C_j ⁺、C_j ^-Respectively represent the optimal index and the worst index of the jth class target index, J₁Represents a positive index set, J₂Representing a negative set of indicators;

determining an optimal distance d of the target object_i ⁺And the worst distance d_i ^-And satisfies the following conditions:

alternatively, the first and second electrodes may be,

alternatively, the first and second electrodes may be,

in one possible implementation manner, in a case that a jth type target index is an index related to temperature, an optimal index of the jth type target index is set to a fixed value, and a first worst index smaller than the optimal index and a second worst index larger than the optimal index are set for the jth type target index;

and the difference value deltaq between the target index of the target object and the worst index of the j-th class target index_jAnd satisfies the following conditions:

wherein, c_1,j ^-、c_2,j ^-Respectively represent the first worst index, the second worst index, C_j ⁺And the optimal index represents the j-th type target index.

In one possible implementation, the constructing the decision matrix Q includes:

normalizing the original value of the jth target index of the ith target object, and taking the normalized result as the element Q of the jth row and the jth column in the decision matrix Q_ij(ii) a And satisfies:

In one possible implementation manner, the determining, by the first scoring module 22, the cell score of each battery cell according to the cell index of each battery cell includes: when the current voltage of the battery monomer is zero or the current voltage change rate exceeds a safety threshold, setting the monomer score of the battery monomer as a minimum score;

and/or

The second scoring module 24 determines module scoring of each battery module according to the module index of each battery module, including: and under the condition that the monomer score of at least one battery monomer in the battery module is the minimum score, setting the module score of the battery module as the minimum score.

In one possible implementation manner, when the battery module is at rest, the current voltage of the battery cell is the open-circuit voltage of the battery cell;

and under the condition of charging and discharging the battery module, the current voltage of the battery monomer is the real-time voltage of the battery monomer.

In addition, an embodiment of the present invention further provides an electronic device, which includes a bus, a transceiver, a memory, a processor, and a computer program stored in the memory and capable of running on the processor, where the transceiver, the memory, and the processor are connected via the bus, and when the computer program is executed by the processor, the processes of the method for battery safety assessment are implemented, and the same technical effects can be achieved, and are not described herein again to avoid repetition.

Specifically, referring to fig. 3, an electronic device according to an embodiment of the present invention includes a bus 1110, a processor 1120, a transceiver 1130, a bus interface 1140, a memory 1150, and a user interface 1160.

In an embodiment of the present invention, the electronic device further includes: a computer program stored on the memory 1150 and executable on the processor 1120, the computer program when executed by the processor 1120 implementing the various processes of the method embodiments of battery safety assessment described above.

A transceiver 1130 for receiving and transmitting data under the control of the processor 1120.

In embodiments of the invention in which a bus architecture (represented by bus 1110) is used, bus 1110 may include any number of interconnected buses and bridges, and bus 1110 may connect various circuits including one or more processors, represented by processor 1120, and a memory, represented by memory 1150.

Bus 1110 represents one or more of any of several types of bus structures, including a memory bus, and memory controller, a peripheral bus, an Accelerated Graphics Port (AGP), a processor, or a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include: industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA), Peripheral Component Interconnect (PCI) bus.

Processor 1120 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits in hardware or instructions in software in a processor. The processor described above includes: general purpose processors, Central Processing Units (CPUs), Network Processors (NPs), Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), Complex Programmable Logic Devices (CPLDs), Programmable Logic Arrays (PLAs), Micro Control Units (MCUs) or other Programmable Logic devices, discrete gates, transistor Logic devices, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. For example, the processor may be a single core processor or a multi-core processor, which may be integrated on a single chip or located on multiple different chips.

Processor 1120 may be a microprocessor or any conventional processor. The steps of the method disclosed in connection with the embodiments of the present invention may be directly performed by a hardware decoding processor, or may be performed by a combination of hardware and software modules in the decoding processor. The software modules may be located in a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable Programmable ROM (EPROM), a register, and other readable storage media known in the art. The readable storage medium is located in the memory, and the processor reads the information in the memory and combines the hardware to complete the steps of the method.

The bus 1110 may also connect various other circuits such as peripherals, voltage regulators, or power management circuits to provide an interface between the bus 1110 and the transceiver 1130, as is well known in the art. Therefore, the embodiments of the present invention will not be further described.

The transceiver 1130 may be one element or may be multiple elements, such as multiple receivers and transmitters, providing a means for communicating with various other apparatus over a transmission medium. For example: the transceiver 1130 receives external data from other devices, and the transceiver 1130 transmits data processed by the processor 1120 to other devices. Depending on the nature of the computer system, a user interface 1160 may also be provided, such as: touch screen, physical keyboard, display, mouse, speaker, microphone, trackball, joystick, stylus.

It is to be appreciated that in embodiments of the invention, the memory 1150 may further include memory located remotely with respect to the processor 1120, which may be coupled to a server via a network. One or more portions of the above-described networks may be an ad hoc network (ad hoc network), an intranet (intranet), an extranet (extranet), a Virtual Private Network (VPN), a Local Area Network (LAN), a Wireless Local Area Network (WLAN), a Wide Area Network (WAN), a Wireless Wide Area Network (WWAN), a Metropolitan Area Network (MAN), the Internet (Internet), a Public Switched Telephone Network (PSTN), a plain old telephone service network (POTS), a cellular telephone network, a wireless fidelity (Wi-Fi) network, and combinations of two or more of the above. For example, the cellular telephone network and the wireless network may be a global system for Mobile Communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Worldwide Interoperability for Microwave Access (WiMAX) system, a General Packet Radio Service (GPRS) system, a Wideband Code Division Multiple Access (WCDMA) system, a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a long term evolution-advanced (LTE-a) system, a Universal Mobile Telecommunications (UMTS) system, an enhanced Mobile Broadband (eMBB) system, a mass Machine Type Communication (mtc) system, an Ultra Reliable Low Latency Communication (urrllc) system, or the like.

It is to be understood that the memory 1150 in embodiments of the present invention can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. Wherein the nonvolatile memory includes: Read-Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically Erasable PROM (EEPROM), or Flash Memory.

The volatile memory includes: random Access Memory (RAM), which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as: static random access memory (Static RAM, SRAM), Dynamic random access memory (Dynamic RAM, DRAM), Synchronous Dynamic random access memory (Synchronous DRAM, SDRAM), Double Data Rate Synchronous Dynamic random access memory (Double Data Rate SDRAM, DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), and Direct memory bus RAM (DRRAM). The memory 1150 of the electronic device described in the embodiments of the invention includes, but is not limited to, the above and any other suitable types of memory.

In an embodiment of the present invention, memory 1150 stores the following elements of operating system 1151 and application programs 1152: an executable module, a data structure, or a subset thereof, or an expanded set thereof.

Specifically, the operating system 1151 includes various system programs such as: a framework layer, a core library layer, a driver layer, etc. for implementing various basic services and processing hardware-based tasks. Applications 1152 include various applications such as: media Player (Media Player), Browser (Browser), for implementing various application services. A program implementing a method of an embodiment of the invention may be included in application program 1152. The application programs 1152 include: applets, objects, components, logic, data structures, and other computer system executable instructions that perform particular tasks or implement particular abstract data types.

In addition, an embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the computer program implements each process of the above-mentioned method for battery safety assessment, and can achieve the same technical effect, and in order to avoid repetition, details are not repeated here.

The computer-readable storage medium includes: permanent and non-permanent, removable and non-removable media may be tangible devices that retain and store instructions for use by an instruction execution apparatus. The computer-readable storage medium includes: electronic memory devices, magnetic memory devices, optical memory devices, electromagnetic memory devices, semiconductor memory devices, and any suitable combination of the foregoing. The computer-readable storage medium includes: phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), non-volatile random access memory (NVRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic tape cartridge storage, magnetic tape disk storage or other magnetic storage devices, memory sticks, mechanically encoded devices (e.g., punched cards or raised structures in a groove having instructions recorded thereon), or any other non-transmission medium useful for storing information that may be accessed by a computing device. As defined in embodiments of the present invention, the computer-readable storage medium does not include transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses traveling through a fiber optic cable), or electrical signals transmitted through a wire.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus, electronic device and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions in actual implementation, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may also be an electrical, mechanical or other form of connection.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to solve the problem to be solved by the embodiment of the invention.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present invention may substantially or partially contribute to the prior art, or all or part of the technical solutions may be embodied in the form of a software product stored in a storage medium, and including several instructions for causing a computer device (including a personal computer, a server, a data center or other network devices) to execute all or part of the steps of the methods according to the embodiments of the present invention. And the storage medium includes various media that can store the program code as listed in the foregoing.

In the description of the embodiments of the present invention, it should be apparent to those skilled in the art that the embodiments of the present invention can be embodied as methods, apparatuses, electronic devices, and computer-readable storage media. Thus, embodiments of the invention may be embodied in the form of: entirely hardware, entirely software (including firmware, resident software, micro-code, etc.), a combination of hardware and software. Furthermore, in some embodiments, embodiments of the invention may also be embodied in the form of a computer program product in one or more computer-readable storage media having computer program code embodied in the medium.

The computer-readable storage media described above may take any combination of one or more computer-readable storage media. The computer-readable storage medium includes: an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of the computer-readable storage medium include: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only Memory (ROM), an erasable programmable read-only Memory (EPROM), a Flash Memory, an optical fiber, a compact disc read-only Memory (CD-ROM), an optical storage device, a magnetic storage device, or any combination thereof. In embodiments of the invention, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, device, or apparatus.

The computer program code embodied on the computer readable storage medium may be transmitted using any appropriate medium, including: wireless, wire, fiber optic cable, Radio Frequency (RF), or any suitable combination thereof.

Computer program code for carrying out operations for embodiments of the present invention may be written in assembly instructions, Instruction Set Architecture (ISA) instructions, machine related instructions, microcode, firmware instructions, state setting data, integrated circuit configuration data, or in one or more programming languages, including an object oriented programming language, such as: java, Smalltalk, C + +, and also include conventional procedural programming languages, such as: c or a similar programming language. The computer program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be over any of a variety of networks, including: a Local Area Network (LAN) or a Wide Area Network (WAN), which may be connected to the user's computer, may be connected to an external computer.

The method, the device and the electronic equipment are described through the flow chart and/or the block diagram.

It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions. These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner. Thus, the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The above description is only a specific implementation of the embodiments of the present invention, but the scope of the embodiments of the present invention is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the embodiments of the present invention, and all such changes or substitutions should be covered by the scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method of battery safety assessment, comprising:

determining a single score of each battery cell according to the single index of each battery cell, wherein the single score is used for expressing the health degree of the battery cell;

2. The method of claim 1, wherein the module indicator further comprises a voltage statistic and/or a temperature statistic of a plurality of the cells in the battery module;

3. The method of claim 1,

the determining the cell score of each battery cell according to the cell index of each battery cell includes: taking the single battery as a target object, taking the single index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as the corresponding single score;

and/or

The module score according to every battery module's module index is confirmed every battery module includes: taking the battery module as a target object, taking the module index as a target index, executing a process of determining a target score of the target object based on the target index, and taking the determined target score as the corresponding module score;

determining the weight of each type of target index;

4. The method of claim 3, wherein determining the weight of each type of the target metric comprises:

wherein the content of the first and second substances,

5. the method of claim 3, wherein determining the target score of the target object by weighting each of the target metrics comprises:

According to the optimal distance d_i ⁺And said worst distance d_i ^-Determining a target score of the target object, the target score of the target object and the optimal distance d_i ⁺Is in negative correlation with the worst distance d_i ^-The two are in positive correlation.

6. The method according to claim 5, wherein the difference between the target index of the target object and the optimal index of the target index of the corresponding class is weighted to determine the optimal distance d_i ⁺(ii) a Weighting the difference value between the target index of the target object and the worst index of the target index of the corresponding class to determine the worst distance d_i ^-The method comprises the following steps:

C_j ⁺＝{(maxq_ij|j∈J₁),(minq_ij|j∈J₂)}；

C_j ^-＝{(minq_ij|j∈J₁),(maxq_ij|j∈J₂)}；

wherein, C_j ⁺、C_j ^-Respectively representing the optimal index and the worst index of the jth class target index, J₁Represents a positive index set, J₂Representing a negative set of indicators;

alternatively, the first and second electrodes may be,

alternatively, the first and second electrodes may be,

7. the method according to claim 5 or 6, characterized in that in a case where a j-th type target index is an index related to temperature, an optimum index of the j-th type target index is set to a fixed value, and a first worst index smaller than the optimum index and a second worst index larger than the optimum index are set for the j-th type target index;

8. The method of claim 4 or 6, wherein the constructing the decision matrix Q comprises:

normalizing the original value of the jth target index of the ith target object, and taking the normalized result as the element Q of the jth row and the jth column in the decision matrix Q_ij(ii) a And satisfies the following conditions:

9. The method of claim 1,

the determining the cell score of each battery cell according to the cell index of each battery cell includes: when the current voltage of the battery monomer is zero or the current voltage change rate exceeds a safety threshold, setting the monomer score of the battery monomer as a minimum score;

and/or

The module score according to every battery module's module index is confirmed every battery module includes: and under the condition that the monomer score of at least one battery monomer in the battery module is the minimum score, setting the module score of the battery module as the minimum score.

10. The method of claim 1,

under the condition that the battery module is static, the current voltage of the battery monomer is the open-circuit voltage of the battery monomer;

11. An apparatus for battery safety assessment, comprising:

the first acquisition module is used for acquiring single indexes of a plurality of single batteries in a battery module, wherein the single indexes comprise voltage differences and temperatures of the single batteries, and the voltage differences of the single batteries are differences between current voltages and standard voltages of the single batteries;

the first scoring module is used for determining a single score of each battery cell according to a single index of each battery cell, and the single score is used for expressing the health degree of the battery cells;

12. An electronic device comprising a bus, a transceiver, a memory, a processor and a computer program stored on the memory and executable on the processor, the transceiver, the memory and the processor being connected via the bus, characterized in that the computer program realizes the steps in the method for battery safety assessment according to any of claims 1 to 10 when executed by the processor.

13. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of battery safety assessment according to any one of claims 1 to 10.