CN113655396B - Method and system for diagnosing connection state of power loop of battery pack and management system - Google Patents
Method and system for diagnosing connection state of power loop of battery pack and management system Download PDFInfo
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- CN113655396B CN113655396B CN202010399392.9A CN202010399392A CN113655396B CN 113655396 B CN113655396 B CN 113655396B CN 202010399392 A CN202010399392 A CN 202010399392A CN 113655396 B CN113655396 B CN 113655396B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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Abstract
The invention provides a method and a system for diagnosing the power connection state of a battery pack, a storage medium, a battery management system and a vehicle, wherein the method comprises the following steps: acquiring a detection signal of a battery pack and a detection signal of each electric core in the battery pack; obtaining the internal resistance value of each battery cell according to the detection signal of the battery pack and the detection signal of each battery cell in the battery pack, obtaining the internal resistance value of a first whole battery pack of the battery pack according to the internal resistance value of each battery cell and the total connection resistance value of the battery pack, and obtaining the internal resistance value of a second whole battery pack of the battery pack according to the detection signal of the battery pack; and determining the connection state of the power circuit of the battery pack according to the first whole-pack internal resistance value at the current moment and the first whole-pack internal resistance value at the previous moment, and the second whole-pack internal resistance value at the current moment and the second whole-pack internal resistance value at the previous moment. According to the method for diagnosing the connection state of the power circuit of the battery pack, disclosed by the embodiment of the invention, the real-time performance and the reliability of power circuit diagnosis are improved by comparing the internal resistance values of the two whole packs in real time.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to a method and a system for diagnosing the connection state of a power circuit of a battery pack, a computer storage medium, a battery management system and a vehicle.
Background
The battery management system needs to measure the voltage and temperature of the single battery cell and collect the total voltage and current of the whole battery pack. And calculating the internal resistance R1 of the whole packed battery in real time according to the total voltage and the total current of the whole packed battery, and judging whether the high-voltage loop has abnormal connection or not by comparing the current battery internal resistance R1 with the initial total resistance R0, for example, R1 is greater than 10R 0.
However, since the internal resistance of the battery has an important relationship with the aging, temperature and SOC (State of Charge) State of the battery, the internal resistance of each cell is different, and the calculation of the internal resistance of the whole pack estimated is also changed under the aging or different temperature conditions of the battery, and it is inaccurate to compare the initial internal resistance with the internal resistance of the whole pack. Taking the influence of temperature on the internal resistance of the battery as an example, the internal resistance of the battery cell may have a large difference at different temperatures, and for a ternary battery, the change of the internal resistance of the battery cell may exceed an order of magnitude along with the decrease of the temperature, for example, the internal resistance of the battery cell changes from 0.1-1m Ω to 1-10m Ω at a low temperature of-20 ℃. It can be seen that the estimated internal resistance of the battery becomes an order of magnitude higher than the normal temperature, which makes the above-mentioned fixed proportional relationship between the internal resistance of the battery and the initial total resistance invalid, thereby making the diagnosis of the connection state of the high-voltage circuit deviated.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide a method for diagnosing a connection state of a power circuit of a battery pack, which can improve the real-time performance and reliability of power circuit diagnosis.
A second object of the invention is to propose a non-transitory computer storage medium.
A third objective of the present invention is to provide a battery management system.
A fourth object of the present invention is to provide a system for diagnosing a connection state of a power circuit of a battery pack.
A fifth object of the invention is to propose a vehicle.
In order to achieve the above object, a first aspect of the present invention provides a method for diagnosing a connection state of a power circuit of a battery pack, the method including: acquiring a detection signal of a battery pack and a detection signal of each battery cell in the battery pack; obtaining the internal resistance value of each electric core according to the detection signal of the battery pack and the detection signal of each electric core in the battery pack, obtaining the internal resistance value of a first whole battery pack of the battery pack according to the internal resistance value of each electric core and the internal resistance value of the battery pack, and obtaining the internal resistance value of a second whole battery pack of the battery pack according to the detection signal of the battery pack; and determining the connection state of the power circuit of the battery pack according to the first whole-pack internal resistance value at the current moment and the first whole-pack internal resistance value at the previous moment, and the second whole-pack internal resistance value at the current moment and the second whole-pack internal resistance value at the previous moment.
According to the method for diagnosing the power loop connection state of the battery pack, whether the power loop of the battery pack is open or not is judged by obtaining the first whole-pack internal resistance value and the second whole-pack internal resistance value, comparing the resistance value change of the first whole-pack internal resistance value and the resistance value change of the second whole-pack internal resistance value at the adjacent moment, namely, the comparison threshold value for evaluating the internal resistance of the battery pack is the sum of the cell internal resistance value and the connection internal resistance value of the battery pack, the adopted comparison threshold value is dynamic and contains the state information of the battery pack, and the first whole-pack internal resistance value and the second whole-pack internal resistance value are variable calculation and are synchronously changed, so that the problems of inconsistent connection impedance and open circuit connection of the power loop can be timely reflected.
In some embodiments, the determining the connection state of the power circuit of the battery pack according to the first whole-pack internal resistance value at the current moment and the first whole-pack internal resistance value at the previous moment, and the second whole-pack internal resistance value at the current moment and the second whole-pack internal resistance value at the previous moment comprises: and if the current-time first whole-pack internal resistance value is within a first preset internal resistance range compared with the previous-time first whole-pack internal resistance value and the current-time second whole-pack internal resistance value is greater than a first internal resistance threshold value compared with the previous-time second whole-pack internal resistance value, determining that an open circuit exists at the connection part of the power circuit of the battery pack.
In some embodiments, the determining the connection state of the power circuit of the battery pack according to the first whole-pack internal resistance value at the current time and the first whole-pack internal resistance value at the previous time, and the second whole-pack internal resistance value at the current time and the second whole-pack internal resistance value at the previous time further includes: and comparing the current time first whole packet internal resistance value with the previous time first whole packet internal resistance value, and comparing the current time second whole packet internal resistance value with the previous time second whole packet internal resistance value, wherein the current time second whole packet internal resistance value is larger than the first internal resistance threshold value, determining that an open circuit exists in the battery core of the battery pack.
In some embodiments, the first internal resistance threshold is a preset multiple of the second whole packet internal resistance value at the previous moment; the second internal resistance threshold value is the first whole packet internal resistance value at the previous moment of preset multiple.
In some embodiments, obtaining the internal cell resistance of each cell according to the detection signal of the battery pack and the detection signal of each cell in the battery pack, and obtaining the first entire pack internal resistance of the battery pack according to the internal cell resistance of each cell and the connection resistance value of the battery pack, include: summing all the cell internal resistance values of the battery pack to obtain a cell total internal resistance value; summing all connection resistance values of the battery pack to obtain a connection total resistance value; and summing the total internal resistance value of the battery core and the total connection resistance value to obtain a first whole pack internal resistance value of the battery pack.
In some embodiments, all of the connection resistance values of the battery pack include a connection resistance value between the battery modules in the battery pack, and a connection resistance value between the battery pack and the distribution box. In order to achieve the above object, a second aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, the computer program, when executed, implementing any of the above methods for diagnosing a battery pack power circuit connection state.
In order to achieve the above object, a third aspect of the present invention provides a battery management system, including: a processor; a memory communicatively coupled to the processor; wherein the memory stores a computer program executable by the processor, and the processor executes the computer program to implement the method for diagnosing the power circuit connection state of the battery pack mentioned in the above embodiment.
According to the battery management system provided by the embodiment of the invention, the connection state of the power circuit of the battery pack can be determined by executing the method for diagnosing the connection state of the power circuit of the battery pack through the processor, so that the proportional relation failure caused by various factors such as temperature change is avoided, and the reliability of power circuit diagnosis is improved.
In order to achieve the above object, a fourth aspect of the present invention provides a system for diagnosing a connection state of a power circuit of a battery pack, the system including: the battery cell monitoring circuit is used for detecting the voltage value of each battery cell in the battery pack; the high-voltage monitoring unit is used for detecting the current value of the battery pack; in the battery management system according to the above embodiment, the battery management system is connected to the cell monitoring circuit and the high-voltage monitoring unit respectively.
According to the system for diagnosing the connection state of the power loop of the battery pack, disclosed by the embodiment of the invention, the battery core monitoring circuit and the high-voltage monitoring circuit are adopted to respectively detect the battery core voltage value and the battery pack current value of each battery core, and the method for diagnosing the connection state of the power loop of the battery pack is executed by combining the battery management system, so that the proportional relation failure caused by various factors such as temperature change is avoided, and the reliability of power loop diagnosis is improved.
In order to achieve the above object, an embodiment of a fifth aspect of the invention proposes a vehicle including: the battery pack comprises at least one battery module, and each battery module comprises a plurality of battery cores; the above embodiments provide a system for diagnosing a connection state of a power circuit of a battery pack, which is used for diagnosing a connection state of a power circuit of a battery pack.
According to the vehicle provided by the embodiment of the invention, by adopting the system for diagnosing the connection state of the power circuit of the battery pack, the proportional relation failure caused by various factors such as temperature change is avoided, and the reliability of power circuit diagnosis is improved.
In some embodiments, the at least one battery module is connected in series, and the battery pack is connected to a distribution box of the vehicle.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of a method of diagnosing a battery pack power loop connection status according to one embodiment of the present invention;
fig. 2 is a schematic diagram of the internal resistance distribution of a battery pack according to one embodiment of the invention;
fig. 3 is a schematic diagram of a first-order equivalent circuit model of a cell according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a battery pack circuit model according to one embodiment of the invention;
FIG. 5 is a block diagram of a battery management system according to one embodiment of the present invention;
FIG. 6 is a block diagram of a system for diagnosing a battery pack power circuit connection status according to one embodiment of the present invention;
FIG. 7 is a block diagram of a vehicle according to one embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.
In the related art, along with environmental changes and changes of battery internal resistance due to self aging, the connection state of the high-voltage loop is diagnosed according to the fixed proportional relation between the battery internal resistance and the initial total resistance, which may cause inaccurate conditions, and further, if the multiple relation between the battery internal resistance R1 and the initial total resistance R0 is too widened, for example, the initial internal resistance R1 is increased, that is, the comparison threshold of the power loop is increased, which may cause a problem that the connection impedance of the power loop cannot be rapidly judged to be increased.
In order to solve the above-described problems, a method of diagnosing a battery pack power circuit connection state according to an embodiment of the first aspect of the present invention is described below with reference to fig. 1 to 4. As shown in fig. 1, the method for diagnosing the connection state of the power circuit of the battery pack according to the embodiment of the present invention includes at least step S1, step S2 and step S3, each of which is described in detail below.
Step S1, obtaining a detection signal of a battery pack and a detection signal of each battery cell in the battery pack.
In an embodiment, the battery pack includes a plurality of battery modules, each battery module includes a plurality of battery cells, and the plurality of battery cells may be connected in series or in parallel or in series and parallel to obtain a battery pack detection signal, such as a battery pack current value and a battery pack terminal voltage value; a detection signal of each cell in the battery pack, for example, a cell voltage value of each cell, is obtained.
Fig. 2 is a schematic diagram of a battery pack structure and its connections according to an embodiment of the present invention. Including two battery modules in fig. 2, each battery module has 12 electric cores, and each electric core has internal resistance R 0 The detection signal of each cell, for example, the cell voltage value, is recorded as U Cell The battery pack detection signal, for example, the battery pack current value is designated as PackI, and the battery pack terminal voltage value is designated as PackV. In an embodiment, a battery management system may be used to collect a battery pack current value PackI, a battery pack terminal voltage value PackV, and a cell voltage value U of each cell in a battery pack Cell And storing the current and voltage values into a memory.
And S2, obtaining the internal resistance value of each battery cell according to the detection signal of the battery pack and the detection signal of each battery cell in the battery pack, obtaining the internal resistance value of a first whole battery pack of the battery pack according to the internal resistance value of each battery cell and the internal resistance value of the battery pack, and obtaining the internal resistance value of a second whole battery pack of the battery pack according to the detection signal of the battery pack.
Fig. 3 is a schematic diagram of a first-order equivalent circuit model of a battery cell according to an embodiment of the present invention. The cell voltage value U of each cell can be detected by the cell monitoring circuit Cell Disclosure of the inventionDetecting the current value PackI of the battery pack by the over-high voltage monitoring unit, estimating the internal resistance of each battery cell by an algorithm, and calculating the voltage value U of each battery cell Cell And a battery pack current value PackI as an input variable, for example, as a kalman filtering algorithm of a first-order equivalent circuit model shown in fig. 3, calculating to obtain an electric core internal resistance value of each electric core, for example, recording as R 0 . The Kalman filtering algorithm is an algorithm for optimally estimating the system state by using a linear system state equation and inputting and outputting observation data through a system.
As shown in fig. 4, which is a schematic diagram of a battery pack circuit model according to an embodiment of the present invention, a battery pack terminal voltage value PackV and a battery pack current value PackI are monitored by a high-voltage monitoring unit, and according to the battery pack circuit model, the battery pack terminal voltage value PackV and the battery pack current value PackI are used as input variables, for example, a second whole-pack internal resistance value of the battery pack is calculated and obtained based on the battery pack circuit model shown in fig. 4, and is, for example, denoted as R 2 。
According to the first-order equivalent circuit of the battery core and the battery pack circuit model, a first whole pack internal resistance value and a second whole pack internal resistance value can be obtained through calculation.
And S3, determining the connection state of the power loop of the battery pack according to the first whole-pack internal resistance value at the current moment and the first whole-pack internal resistance value at the previous moment, and the second whole-pack internal resistance value at the current moment and the second whole-pack internal resistance value at the previous moment.
For example, a first whole packet internal resistance difference value of the first whole packet internal resistance values at two adjacent moments is calculated, a second whole packet internal resistance difference value of the two adjacent moments is calculated, and the connection state of the power circuit of the battery pack is determined according to the first whole packet internal resistance difference value and the second whole packet internal resistance difference value.
According to the method for diagnosing the power loop connection state of the battery pack, whether the power loop of the battery pack is open or not is judged by obtaining the first whole-pack internal resistance value and the second whole-pack internal resistance value, comparing the resistance value change of the first whole-pack internal resistance value and the resistance value change of the second whole-pack internal resistance value at the adjacent moment, namely, the comparison threshold for evaluating the internal resistance of the battery pack is the sum of the cell internal resistance value and the connection internal resistance value of the battery pack, the adopted comparison threshold is dynamic and contains the state information of the battery pack, the first whole-pack internal resistance value and the second whole-pack internal resistance value are calculated in real time and are synchronously changed, the problems of inconsistent connection impedance and power loop connection open circuit can be timely reflected, and compared with the method for judging the power loop state by using the fixed proportional relation of the internal resistance of the battery pack, the proportional relation failure caused by various factors such as temperature change can be avoided, and the reliability of power loop diagnosis is improved.
In some embodiments, determining the power circuit connection status of the battery pack according to the first full pack internal resistance value at the current moment and the first full pack internal resistance value at the previous moment, and the second full pack internal resistance value at the current moment and the second full pack internal resistance value at the previous moment comprises: and if the current-time first whole-pack internal resistance value is within the first preset internal resistance range compared with the previous-time first whole-pack internal resistance value and the current-time second whole-pack internal resistance value is larger than the first internal resistance threshold compared with the previous-time second whole-pack internal resistance value, determining that an open circuit exists at the connection position of the power circuit of the battery pack.
In an embodiment, the first preset internal resistance range is a tolerable range of the first whole packet of internal resistance value change, for example, the first preset internal resistance range may be: under the condition of low temperature, when the SOC =0, the maximum value of the first whole package internal resistance is taken as an upper limit value; when the SOC =60 under normal temperature conditions, the lower limit value is set to the value at which the first whole-pack internal resistance is minimum, that is, the first whole-pack internal resistance R is set to the value at which the first whole-pack internal resistance R is minimum under all SOC conditions at different operating temperatures 1 The variation ranges of the internal resistance values are all within a first preset internal resistance range, namely compared with a first whole-packet internal resistance value at the previous moment, the variation of the first whole-packet internal resistance value at the current moment is within the first preset internal resistance range, the first whole-packet internal resistance value is considered to be not changed or almost not changed, compared with a second whole-packet internal resistance value at the previous moment, the second whole-packet internal resistance value at the current moment is larger than a first internal resistance threshold value, wherein the first internal resistance threshold value is a preset multiple of the second whole-packet internal resistance value at the previous moment, namely the second whole-packet internal resistance values at two adjacent moments are suddenly changed, and the open circuit is determined to exist at the connection position of the power circuit of the battery pack.
In other embodiments, by counting two adjacent time instantsDetermining whether the difference value of the internal resistance of the first whole package is within a first preset internal resistance range, for example, the internal resistance value of the first whole package of the battery pack at the moment K is recorded as R 1 (k) And the first full packet internal resistance at time K-1 is recorded as R 1 (K-1), the internal resistance difference value at the K-th moment and the K-1 moment is a first whole packet internal resistance difference value and is recorded as delta R 1 (k)，△R 1 (k)＝R 1 (k)-R 1 (k-1), when Δ R 1 (k) When the internal resistance is within the first preset internal resistance range, the R is considered to be 1 (k) Is within a reasonable range, the first whole package is considered to have an unchanged internal resistance value.
And calculating the difference value of the internal resistance values of the second whole package at two adjacent moments, and determining whether the difference value of the internal resistance of the second whole package is greater than the first internal resistance threshold value, for example, the internal resistance value of the second whole package of the battery pack at the moment K is recorded as R 2 (k) And the resistance value in the second whole packet at the moment K-1 is recorded as R 2 (K-1), the internal resistance difference value at the K time and the K-1 time is a second integral internal resistance difference value, and is recorded as delta R 2 (k)，△R 2 (k)＝R 2 (k)-R 2 (k-1), when Δ R 2 (k) And when the internal resistance value of the second whole packet is larger than the first internal resistance threshold value, considering that the internal resistance values of the second whole packet are different by 2-10 times at adjacent moments, and determining that the power loop of the battery pack is in an open circuit state by combining the fact that the internal resistance value of the first whole packet is unchanged.
Or, calculating the second whole internal resistance value R 2 (k) The difference between the internal resistances at the K-1 th time and the K-2 th time is recorded as Δ R 2 (k-1)，△R 2 (k-1)＝R 2 (k-1)-R 2 (k-2). Comparison of Δ R 2 (k) And Δ R 2 (k-1) if Δ R 2 (k) And Δ R 2 And (k-1) determining that the internal resistance value of the second whole package changes suddenly when the difference between the internal resistance values is 2-10 times, and determining that the battery package loop is in an open circuit state by combining the same situation that the internal resistance value of the first whole package is unchanged.
In some embodiments, determining the connection state of the power circuit of the battery pack according to the first internal resistance value of the battery pack at the current time and the first internal resistance value of the battery pack at the previous time, and the second internal resistance value of the battery pack at the current time and the second internal resistance value of the battery pack at the previous time, further includes: comparing the current time first whole package internal resistance value with the previous time first whole package internal resistance value, the current time first whole package internal resistance value is larger than the second internal resistance threshold value, and comparing the current time second whole package internal resistance value with the previous time second whole package internal resistance value, the second whole package internal resistance value is larger than the first internal resistance threshold value, and then it is determined that an open circuit exists in the battery cell of the battery pack.
In an embodiment, the second internal resistance threshold is a preset multiple of the first internal resistance value in the first whole packet at the previous moment, and the first internal resistance value in the first whole packet at the current moment is greater than the second internal resistance threshold compared with the first internal resistance value in the first whole packet at the previous moment, which indicates that the first internal resistance value in the first whole packet at two adjacent moments differs by 2-10 times, such as R 1 (k)≥5R 1 (k-1), the internal resistance of the first whole package changes abruptly, and the internal resistance of the second whole package is Δ R 2 (k) Greater than a first internal resistance threshold, e.g. R 2 (k)≥5R 2 And (k-1), the internal resistance of the second whole package is suddenly changed, and the internal abnormality of the battery core can be determined.
In other embodiments, the difference Δ R between the internal resistance of the first full packet at time K and at time K-1 is calculated, for example 1 (k) (ii) a Internal resistance difference delta R between the K-1 time and the K-2 time 1 (k-1)，△R 1 (k-1)＝R 1 (k-1)-R 1 (k-2), if Δ R 1 (k) And Δ R 1 (k-1) if the difference is 2-10 times, the internal resistance of the first whole packet is considered to be suddenly changed; and calculating the difference value Delta R of the internal resistance of the second whole packet at the K-th moment and the K-1 moment 2 (k) And the difference value Delta R of the internal resistances of the K-1 time and the K-2 time 2 (k-1)，△R 2 (k-1)＝R 2 (k-1)-R 2 (k-2), if Δ R 2 (k) And Δ R 2 And (k-1) if the difference is 2-10 times, the internal resistance of the second whole package is considered to be suddenly changed, and at the moment, it can be determined that an open circuit exists in the battery cell of the battery package.
In some embodiments, obtaining the internal cell resistance of each cell according to the detection signal of the battery pack and the detection signal of each cell in the battery pack, and obtaining the first entire internal cell resistance of the battery pack according to the internal cell resistance of each cell and the connection resistance value of the battery pack includes: summing all the cell internal resistance values of the battery pack to obtain a cell total internal resistance value; summing all connection resistance values of the battery pack to obtain a connection total resistance value; and summing the total resistance value of the battery core and the total connection resistance value to obtain a first whole-pack internal resistance value of the battery pack.
Referring to fig. 2, the cell internal resistance value of each cell is, for example, denoted as R 0 The total resistance value of all the connections of the battery pack is R CU Summing all the cell internal resistance values to obtain a cell total internal resistance value, which is recorded as ∑ R 0 Summing all the connection resistance values of the battery pack to obtain a total connection resistance value, e.g. as ∑ R CU Obtaining a first whole package internal resistance value, e.g. R 1 ，R 1 ＝∑R 0 +∑R CU 。
Further, in some embodiments, all of the connection resistance values of the battery pack include a connection resistance value between the battery modules in the battery pack, and a connection resistance value of the connection tab between the battery pack and the distribution box.
As shown in fig. 2, all the connection resistance values of the battery pack include the connection resistance value R of the connection tab between the two modules CU The connection resistance value between the module and the distribution box is also R CU The resistance value of the connecting piece between the modules is an initial value of leaving factory, and the initial value is small and can not change. The connection resistance value of the connecting sheet between the module and the distribution box is set as an initial value of factory leaving, and usually does not change, and the connection resistance value sigma R of all the battery packs is obtained by adding the connection resistance value sigma R and the initial value CU 。
In summary, according to the method for diagnosing the connection status of the power circuit of the battery pack in the embodiment of the present invention, by obtaining the internal resistance value of the first whole pack and the internal resistance value of the second whole pack, comparing the internal resistance value changes of the first whole pack and the internal resistance value of the second whole pack at the adjacent time, and determining whether the power circuit of the battery pack is open, i.e. the comparison threshold for evaluating the internal resistance of the battery pack is the sum of the internal resistance value of the battery cell and the connection resistance value of the battery pack, the comparison threshold is dynamic and includes the status information of the battery pack, and the internal resistances of the first whole pack and the second whole pack are calculated in real time and both are synchronously changed, the problems of inconsistent connection impedance and open circuit of the power circuit connection can be reflected in time. And determining the abnormal internal resistance of the battery cell by calculating the internal resistance value of each battery cell.
A computer-readable storage medium according to an embodiment of the second aspect of the present invention has stored thereon a computer program that, when executed, implements the method of diagnosing a battery pack power circuit connection state of any one of the above-mentioned embodiments.
In an embodiment, the computer readable storage medium may be a transitory computer readable storage medium or a non-transitory computer readable storage medium.
A battery management system according to an embodiment of the third aspect of the invention is described below with reference to the drawings.
Fig. 5 is a block diagram of a battery management system according to an embodiment of the present invention, and as shown in fig. 5, a battery management system 10 of an embodiment of the present invention includes a processor 11 and a memory 12.
A memory 12 communicatively coupled to the processor 11; the memory 12 stores a computer program executable by the processor 11, and the processor 11 implements the method for diagnosing the connection state of the power circuit of the battery pack mentioned in the above embodiment when executing the computer program, wherein the implementation process of the method for diagnosing the connection state of the power circuit of the battery pack can be described with reference to the above embodiment.
According to the battery management system 10 of the embodiment of the invention, the processor 11 executes the method for diagnosing the connection state of the power circuit of the battery pack, so that the connection state of the power circuit of the battery pack can be determined, the proportional relation failure caused by various factors such as temperature change is avoided, and the reliability of power circuit diagnosis is improved.
A system for diagnosing a power circuit connection state of a battery pack according to a fourth aspect of the present invention will be described below with reference to the accompanying drawings.
Fig. 6 is a block diagram of a system for diagnosing a connection state of a power circuit of a battery pack according to an embodiment of the present invention, and as shown in fig. 6, a system 20 for diagnosing a connection state of a power circuit of a battery pack according to an embodiment of the present invention includes a cell monitoring circuit 21, a high voltage monitoring unit, and a battery management system 10.
The cell monitoring circuit 21 is configured to detect a cell voltage value of each cell in the battery pack; the high voltage monitoring unit 22 is used for detecting the current value of the battery pack; the battery management system 10 is connected to the cell monitoring circuit 21 and the high voltage monitoring unit 22, respectively.
According to the system 20 for diagnosing the connection state of the power circuit of the battery pack, which is disclosed by the embodiment of the invention, the cell voltage value and the current value of the battery pack of each cell are respectively detected by the cell monitoring circuit 21 and the high-voltage monitoring circuit 22, and the method for diagnosing the connection state of the power circuit of the battery pack is executed by combining the battery management system 10, so that the proportional relation failure caused by various factors such as temperature change is avoided, and the reliability of power circuit diagnosis is improved.
A vehicle according to an embodiment of the fifth aspect of the invention is described below with reference to the drawings.
Fig. 7 is a block diagram of a vehicle according to an embodiment of the invention, and as shown in fig. 7, a vehicle 30 of an embodiment of the invention includes a battery pack 31 and a system 20 for diagnosing a battery pack power circuit connection state.
The battery pack 31 includes at least one battery module 32, and each battery module 32 includes a plurality of battery cells; the system 20 for diagnosing the connection state of the battery pack power circuit is used to diagnose the connection state of the battery pack power circuit.
In some embodiments, at least one battery module 32 is connected in series, and the battery pack 31 is connected with a distribution box of the vehicle 30. And providing data support for obtaining the internal resistance value of the first whole packet.
According to the vehicle 30 of the embodiment of the invention, by adopting the system 20 for diagnosing the connection state of the power circuit of the battery pack, which is mentioned in the embodiment, the proportional relation failure of the power circuit caused by various factors such as temperature change is avoided, and the real-time performance and the reliability of the power circuit diagnosis are improved.
In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (9)
1. A method of diagnosing a battery pack power circuit connection status, comprising:
acquiring a detection signal of a battery pack and a detection signal of each electric core in the battery pack;
obtaining the internal resistance value of each electric core according to the detection signal of the battery pack and the detection signal of each electric core in the battery pack, obtaining the internal resistance value of a first whole battery pack of the battery pack according to the internal resistance value of each electric core and the total connection resistance value of the battery pack, and obtaining the internal resistance value of a second whole battery pack of the battery pack according to the detection signal of the battery pack,
obtaining a first whole internal resistance of the battery pack according to the internal resistance value of each battery cell and the total connection resistance value of the battery pack comprises: summing all the cell internal resistance values of the battery pack to obtain a cell total internal resistance value; summing all connection resistance values of the battery pack to obtain a total connection resistance value; summing the total internal resistance value of the battery core and the total connection resistance value to obtain a first whole internal resistance value of the battery pack, and obtaining a second whole internal resistance value of the battery pack according to the detection signal of the battery pack comprises: monitoring the battery pack end voltage and the battery pack end current, and determining a second whole pack internal resistance value of the battery pack according to the battery pack end voltage, the battery pack end current and a battery pack circuit model;
determining the connection state of the power circuit of the battery pack according to the first whole-pack internal resistance value at the current moment and the first whole-pack internal resistance value at the previous moment, and the second whole-pack internal resistance value at the current moment and the second whole-pack internal resistance value at the previous moment,
determining the battery pack power loop connection state comprises: and if the first whole-pack internal resistance value at the current moment is within a first preset internal resistance range compared with the first whole-pack internal resistance value at the previous moment and the second whole-pack internal resistance value at the current moment is greater than a first internal resistance threshold value compared with the second whole-pack internal resistance value at the previous moment, determining that an open circuit exists at the connection position of the power circuit of the battery pack.
2. The method of diagnosing a battery pack power circuit connection state according to claim 1, wherein the determining a battery pack power circuit connection state based on the first pack internal resistance value at the present time and the first pack internal resistance value at the previous time, and the second pack internal resistance value at the present time and the second pack internal resistance value at the previous time, further comprises:
and comparing the current time first whole packet internal resistance value with the previous time first whole packet internal resistance value, and comparing the current time second whole packet internal resistance value with the previous time second whole packet internal resistance value, wherein the current time second whole packet internal resistance value is larger than the first internal resistance threshold value, determining that an open circuit exists in the battery core of the battery pack.
3. The method for diagnosing the connection state of the power circuit of the battery pack according to claim 2, wherein the first internal resistance threshold value is a preset multiple of the second internal resistance value of the whole battery pack at the previous moment; the second internal resistance threshold value is the first whole internal resistance value at the previous moment of preset multiple.
4. The method of diagnosing a connection status of a power circuit of a battery pack according to claim 1, wherein all connection resistance values of the battery pack include a connection resistance value between battery modules in the battery pack, a connection resistance value between the battery pack and a distribution box.
5. A non-transitory computer storage medium having stored thereon a computer program that, when executed, implements the method of diagnosing a battery pack power circuit connection status of any one of claims 1-4.
6. A battery management system, comprising:
a processor;
a memory communicatively coupled to the processor;
wherein the memory has stored therein a computer program executable by the processor, the processor implementing the method of diagnosing a battery pack power circuit connection status according to any one of claims 1-4 when executing the computer program.
7. A system for diagnosing a battery pack power circuit connection status, comprising:
the battery cell monitoring circuit is used for detecting the voltage value of each battery cell in the battery pack;
the high-voltage monitoring unit is used for detecting the current value of the battery pack;
the battery management system of claim 6, the battery management system being connected to the cell monitoring circuit and the high voltage monitoring unit, respectively.
8. A vehicle, characterized by comprising:
the battery pack comprises at least one battery module, and each battery module comprises a plurality of battery cores;
the system for diagnosing a connection status of a battery pack power circuit of claim 7, which is used for diagnosing a connection status of a battery pack power circuit.
9. The vehicle of claim 8, wherein the at least one battery module is connected in series and the battery pack is connected to a distribution box of the vehicle.
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