CN114152826B - Method for detecting short circuit in lithium ion battery unit - Google Patents

Method for detecting short circuit in lithium ion battery unit Download PDF

Info

Publication number
CN114152826B
CN114152826B CN202111399433.5A CN202111399433A CN114152826B CN 114152826 B CN114152826 B CN 114152826B CN 202111399433 A CN202111399433 A CN 202111399433A CN 114152826 B CN114152826 B CN 114152826B
Authority
CN
China
Prior art keywords
docv
battery
value
ocv
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202111399433.5A
Other languages
Chinese (zh)
Other versions
CN114152826A (en
Inventor
孙逢春
柴志雄
江海赋
李军求
杨子传
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Institute of Technology BIT
Original Assignee
Beijing Institute of Technology BIT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing Institute of Technology BIT filed Critical Beijing Institute of Technology BIT
Priority to CN202111399433.5A priority Critical patent/CN114152826B/en
Publication of CN114152826A publication Critical patent/CN114152826A/en
Application granted granted Critical
Publication of CN114152826B publication Critical patent/CN114152826B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Secondary Cells (AREA)

Abstract

Compared with the prior art, the method for detecting the internal short circuit of the lithium ion battery cell does not need a model-based SOC estimation process, avoids the adverse effect of the defects of the selected model on the precision, and has small calculation amount. In the method, the current dOCV/dQ of the battery to be detected is updated in real time by adopting the LMRLS, so that the calculated amount and the data storage amount are greatly reduced. The whole detection process of the internal short circuit does not depend on the temperature rise phenomenon, so that the limitation of the specification index, the installation position and the like of the temperature sensor can be avoided. Because the method does not depend on data or parameter comparison among the battery cells, the method is suitable for both single battery cells and grouped scenes, and particularly has higher applicability to the lithium iron phosphate battery with a flat open-circuit voltage curve.

Description

Method for detecting short circuit in lithium ion battery unit
Technical Field
The invention belongs to the technical field of battery fault detection, and particularly relates to an internal short circuit detection method suitable for a lithium ion battery monomer.
Background
With the popularization of lithium ion batteries and electric vehicles, the electric vehicle fire accident caused by battery thermal runaway often occurs, and an internal short circuit is one of important inducers of thermal runaway and needs to be rapidly and accurately detected when necessary. In the prior art, methods for detecting short circuits in lithium ion batteries are roughly classified into the following types: 1) Threshold value method: the internal short circuit detection is realized by judging whether the voltage, the temperature, the voltage change rate or the temperature change rate of the battery exceeds a preset threshold value; 2) Electric quantity consumption method: the actual consumed electric quantity of the battery is obtained through an accurate SOC estimation process, and is compared with the used electric quantity (output end current integral) to obtain the battery leakage condition so as to realize detection; 3) Remaining chargeable capacity method: judging the leakage condition of the battery according to the difference of the residual chargeable capacities in the two adjacent charging processes; 4) Comparative analysis method: for the series battery pack, internal short circuit detection is realized by comparing consistency and correlation of voltage or other parameters among single batteries; 5) Sensor measurement: for the parallel battery pack, the detection of the internal short circuit can be realized through a ring circuit topological structure and a circuit sensor.
However, these methods have some drawbacks that limit their applicability or effectiveness, such as thresholding, which tends to be difficult to identify in the early stages of a relatively small degree, and limited by the placement of the temperature sensors; the electric quantity consumption method is greatly influenced by SOC estimation accuracy and is limited by a flat open-circuit voltage curve of the lithium iron phosphate battery, and the method is often difficult to be applied to the lithium iron phosphate battery; the residual chargeable capacity rule needs to be carried out in a charging scene, and cannot be used for sudden internal short circuit faults under the condition of battery discharging operation; the contrastive analysis method requires mutual contrast among the battery cells and cannot be used for scenes of single battery cells; sensor measurements rely on the topology of the circuit and additional current sensors, and are limited in applicability. Therefore, how to provide a more accurate internal short circuit detection method with less self-limitation and wide applicability is a technical problem to be solved in the art.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a method for detecting short circuit in a lithium ion battery cell, which specifically comprises the following steps:
s1, carrying out a small-rate discharge test on a single battery, and respectively obtaining the relationship among the open-circuit voltage OCV, the discharge capacity Q and the state of charge SOC of the single battery;
s2, calculating a standard value of dOCV/dQ according to the relationship between the OCV and the Q obtained in the step S1;
s3, measuring voltage and current data of the target lithium ion battery in real time;
s4, establishing an equivalent circuit model considering the internal short circuit condition for the target lithium ion battery, utilizing the voltage and current data obtained by measurement in the step S3, identifying model parameters on line based on a recursive least square method with forgetting factors, and calculating open-circuit voltage;
s5, aiming at the linear relation among the open-circuit voltage, the discharge capacity and the dOCV/dQ, updating and calculating the dOCV/dQ value in real time based on a recursive least square method and a limited memory recursive least square method by utilizing the open-circuit voltage identified in the step S4 and the measured accumulated discharge capacity;
and S6, comparing the dOCV/dQ value obtained by calculation in S5 with the OCV/dQ standard value obtained in the step S2, and determining that an internal short-circuit fault occurs when the difference value of the two exceeds a preset threshold value, otherwise, returning to S3 to continue to perform detection at the next moment.
Further, the specific process of the small-rate discharge test performed in step S1 includes: firstly, charging a battery monomer to full charge electric quantity in a constant current and constant voltage mode, standing for more than 3 hours, and then discharging to lower cut-off voltage in a constant current mode at a multiplying power less than or equal to 1/20C; the open circuit voltage is equivalent by the terminal voltage in the discharging process; the discharge test also comprises the step of repeatedly carrying out the same battery monomer at different temperatures respectively so as to obtain the open-circuit voltage of the battery at different temperatures; the relation between the equation capacity Q and the state of charge SOC is calculated by using an ampere-hour integration method.
Further, the calculation method of calculating the standard value of dcv/dQ in step S2 includes the following steps:
1) Taking the discharge capacity Q as an independent variable and the open-circuit voltage OCV as a dependent variable, and solving corresponding derivatives under different independent variables to obtain corresponding dOCV/dQ standard values;
2) According to the total capacity of the battery and the relation between the open-circuit voltage OCV and the SOC, spline sampling and derivation are adopted, and the result is converted into a dOCV/dQ standard value result;
the calculation of the standard value of the dOCV/dQ comprises the calculation aiming at different temperature conditions respectively.
Further, step S4 specifically includes the following steps:
1) Selecting one of a Rint model, a first-order RC model, a second-order RC model and the like to establish an equivalent circuit model considering the internal short circuit condition;
2) And identifying the model parameters of the equivalent circuit model according to the voltage and current data measured in the step S3 and based on a recursive least square method with forgetting factors, wherein the process is as follows:
Figure BDA0003364153550000021
in the formula, mu is a forgetting factor, and is usually 0.95 & lt mu & lt 1;
Figure BDA0003364153550000022
in order to input the vector of data,
Figure BDA0003364153550000023
for the parameter vector to be identified, the superscript Λ represents the estimated value of the corresponding parameter,
Figure BDA0003364153550000024
is an output; k is LS,k For RLS gain, P LS,k Is a covariance matrix, I is an identity matrix, and k represents the current time;
3) Calculating and identifying equivalent circuit model open-circuit voltage
Figure BDA0003364153550000025
Further, step S5 specifically includes the following processes:
1) Setting the length L of a memory window;
2) Using linear equations
Figure BDA0003364153550000026
Describes the linear relationship among the open-circuit voltage, the discharge capacity and dOCV/dQ, where y k =U OCV,k
Figure BDA0003364153550000027
Q Ah,k For the accumulated discharge capacity obtained by ampere-hour integration, the parameter vector theta = [ alpha beta ]] T Where the term α is dOCV/dQ, and subscript k denotes the current time;
3) By calculation
Figure BDA0003364153550000031
And Q Ah,k When k is less than or equal to L, updating the parameter vector theta by adopting a recursive least square method, as shown in the following formula:
Figure BDA0003364153550000032
when k is larger than L, updating the parameter vector theta by using a finite memory recursive least square method, wherein the method comprises the following two processes:
1) New data was introduced as shown by the following equation:
Figure BDA0003364153550000033
in the formula, P LS,k-L,k-1 And
Figure BDA0003364153550000034
respectively representing covariance matrix and parameter vector estimated value formed by L groups of measurement data from k-L to k-1; p is LS,k-L,k And
Figure BDA0003364153550000035
respectively representing a covariance matrix and a parameter vector estimation value formed by L +1 groups of measurement data from k-L to k; k LS,k-L,k Is the gain;
2) Removing old data as shown in the following formula:
Figure BDA0003364153550000036
in the formula, P LS,k-L+1,k And
Figure BDA0003364153550000037
respectively representing a covariance matrix and a parameter vector estimation value formed by L groups of measurement data from k-L +1 to k moments; k LS,k-L+1,k In order to obtain the gain of the gain,
Figure BDA0003364153550000038
i.e. the identification value that needs to be updated at the current moment.
Further, step S6 specifically includes:
1) Calculating the SOC of the target lithium ion battery by using the measured data based on an ampere-hour integration method, and determining the dOCV/dQ standard value at the current k moment by combining the relationship between the dOCV/dQ standard value obtained in the step S2 and the SOC;
2) And D, comparing the time k of dOCV/dQ calculated in the step S5 with the standard value of the time k-L/2 in a delayed manner, and determining whether the internal short circuit condition occurs.
Compared with the prior art, the method for detecting the short circuit in the lithium ion battery unit provided by the invention at least has the following beneficial effects:
1. the method does not need a model-based SOC estimation process, avoids the adverse effect of the defects of the selected model on the precision, has small calculated amount and has high practicability.
2. The current dOCV/dQ of the battery to be detected is updated in real time by adopting the LMRLS, so that the calculated amount and the data storage amount are greatly reduced.
3. The method does not depend on the temperature rise phenomenon in the detection process of the internal short circuit, so that the method is not limited by the specification indexes, the installation positions and the like of the temperature sensor.
4. Because data or parameter comparison among the cells is not relied on, the method is suitable for both single cells and grouped scenes.
5. The method has high applicability particularly to the lithium iron phosphate battery with a flat open-circuit voltage curve.
Drawings
FIG. 1 is a flow chart of the overall steps of the method provided by the present invention;
FIG. 2 is a graph of OCV versus SOC and a graph of dOCV/dQ versus SOC obtained in an embodiment of the present invention;
FIG. 3 is a schematic diagram of a first-order RC model for considering internal short circuits according to an embodiment of the present invention;
FIG. 4 shows the results of a test under no short circuit condition in an embodiment of the present invention;
fig. 5 shows the result of the detection under the internal short circuit condition in the embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for detecting short circuit in a lithium ion battery cell, as shown in fig. 1, which specifically comprises the following steps:
s1, carrying out a small-rate discharge test on a single battery, and respectively obtaining the relationship among the open-circuit voltage OCV, the discharge capacity Q and the state of charge SOC of the single battery;
s2, calculating a standard value of dOCV/dQ according to the relationship between the OCV and the Q obtained in the step S1;
s3, measuring voltage and current data of the target lithium ion battery in real time;
s4, establishing an equivalent circuit model considering the internal short circuit condition for the target lithium ion battery, utilizing the voltage and current data obtained by measurement in the step S3, identifying model parameters on line based on a recursive least square method with forgetting factors, and calculating open-circuit voltage;
s5, aiming at the linear relation among the open-circuit voltage, the discharge capacity and the dOCV/dQ, updating and calculating the dOCV/dQ value in real time based on a recursive least square method and a limited memory recursive least square method by using the open-circuit voltage identified in the step S4 and the measured accumulated discharge capacity;
and S6, comparing the dOCV/dQ value obtained by calculation in S5 with the OCV/dQ standard value obtained in the step S2, and determining that an internal short-circuit fault occurs when the difference value of the two exceeds a preset threshold value, otherwise, returning to S3 to continue to perform detection at the next moment.
In a preferred embodiment of the present invention, the specific process of the small-rate discharge test performed in step S1 includes: firstly, charging a battery monomer to full charge capacity in a constant-current constant-voltage mode, standing for more than 3 hours, and then discharging to lower cut-off voltage of 2.5V in a constant-current manner at a rate of 1/20C; the collected voltage is regarded as the OCV of the battery because the discharge rate is lower; and the discharge capacity and the SOC are calculated by an ampere-hour integration method according to the acquired current data. The solid line in fig. 2 shows the OCV versus SOC.
In a preferred embodiment of the present invention, in step S2, the relationship between the dvcv/dQ standard value and the discharge capacity is first obtained by fitting and deriving a smooth spline curve, and further, the relationship between the dvcv/dQ and the discharge capacity is converted into a relationship between the dvcv/dQ and the SOC according to the total battery capacity, as shown by a dashed-dotted line in fig. 2.
In a preferred embodiment of the present invention, the target battery to be detected is tested in the online detection stage under Dynamic Stress Test (DST) and Federal Urban operation (FUDS). And acquiring current and voltage data of the battery under corresponding current working conditions in real time at a sampling frequency of 1Hz through a sensor.
In a preferred embodiment of the present invention, step S4 specifically includes the following steps:
1) A first order RC model (including the short circuit resistance) as shown in fig. 3 is selected to establish an equivalent circuit model for the case of the internal short circuit under consideration, as shown in the following equation:
Figure BDA0003364153550000051
wherein t represents time; u shape t ,U OCV ,U 1 Respectively representing a battery terminal voltage, an open circuit voltage and a polarization voltage; r is 0 Is the ohmic internal resistance of the battery, C 1 For polarization capacitance, polarization time constant tau 1 =R 1 C 1 ,R 1 Is the polarization internal resistance; i denotes the current actually passing through the battery, represented by the operating current (i.e. the measured current) I load And short-circuit current I SC Forming; r SC Then the equivalent internal short circuit resistance is represented;
at U OCV,k ≈U OCV,k-1 Under the assumption that the model is discretized into the following linear equation form by a bilinear transformation method:
Figure BDA0003364153550000052
in the formula: y is k =U t,k
Figure BDA0003364153550000053
θ k =[(1-a 1 )U OCV,k a 1 a 2 a 3 ] T
Figure BDA0003364153550000054
Δ t is the sampling interval, I = I when no internal short circuit occurs load
When considering the internal short circuit condition, the short circuit current I is not measured SC The existence of I cannot be accurately measured, and an input vector is required
Figure BDA0003364153550000055
I to I in load The above linear equation can be converted into the following form:
Figure BDA0003364153550000061
in the formula:
Figure BDA0003364153550000062
Figure BDA0003364153550000063
Figure BDA0003364153550000064
2) And identifying the model parameters of the equivalent circuit model according to the voltage and current data measured in the step S3 and based on a recursive least square method with forgetting factors, wherein the process is as follows:
Figure BDA0003364153550000065
in the formula, mu is a forgetting factor, and is usually 0.95 & lt mu & lt 1;
Figure BDA0003364153550000066
in order to input the vector of data,
Figure BDA0003364153550000067
for the parameter vector to be identified, the superscript Λ represents the estimated value of the corresponding parameter,
Figure BDA0003364153550000068
is an output; k LS,k For RLS gain, P LS,k Is a covariance matrix, I is an identity matrix, and k represents the current moment;
to improve the performance of the method, the forgetting factor μ is adaptively adjusted according to the following formula:
Figure BDA0003364153550000069
wherein C represents the battery capacity, | I k I/C indicates the current multiplying power condition of the battery, and zeta is a self-defined parameter for adjusting mu when the zeta is more than or equal to 0 k Approximate numerical ranges of (d);
3) Calculating and identifying equivalent circuit model open-circuit voltage
Figure BDA00033641535500000610
Figure BDA00033641535500000611
In the formula (I), the compound is shown in the specification,
Figure BDA00033641535500000612
and
Figure BDA00033641535500000613
respectively corresponding to the parameter vectors
Figure BDA00033641535500000614
A first element and a second element. Note that when no internal short circuit occurs, the short-circuit resistance R SC Approaching infinity, the OCV calculated by the above equation will be substantially equal to the battery actual OCV; and after an internal short circuit occurs, the OCV calculated according to the above equation will deviate to:
Figure BDA00033641535500000615
significantly lower than the actual OCV. This deviation phenomenon is a key element of the method to be able to detect internal short circuits.
In a preferred embodiment of the present invention, step S5 specifically includes the following processes:
1) Setting the length L of a memory window;
2) Using linear equations
Figure BDA0003364153550000071
Describes the linear relationship among the open-circuit voltage, the discharge capacity and dOCV/dQ, where y k =U OCV,k
Figure BDA0003364153550000072
Q Ah,k For the accumulated discharge capacity obtained by ampere-hour integration, the parameter vector theta = [ alpha beta ]] T Wherein the term α is dOCV/dQ, and subscript k represents the current time;
3) Using calculation
Figure BDA0003364153550000073
And Q Ah,k When k is less than or equal to L, updating the parameter vector theta by adopting a recursive least square method, as shown in the following formula:
Figure BDA0003364153550000074
when k is larger than L, updating the parameter vector theta by using a finite memory recursive least square method, wherein the method comprises the following two processes:
1) New data was introduced as shown by the following equation:
Figure BDA0003364153550000075
in the formula, P LS,k-L,k-1 And
Figure BDA0003364153550000076
respectively representing a covariance matrix and a parameter vector estimation value formed by L groups of measurement data from k-L to k-1; p LS,k-L,k And
Figure BDA0003364153550000077
respectively representing a covariance matrix and a parameter vector estimation value formed by L +1 groups of measurement data from k-L to k; k is LS,k-L,k Is the gain;
2) Removing old data as shown in the following formula:
Figure BDA0003364153550000078
in the formula, P LS,k-L+1,k And
Figure BDA0003364153550000079
respectively representing a covariance matrix and a parameter vector estimation value formed by L groups of measurement data from k-L +1 to k moments; k LS,k-L+1,k In order to achieve the gain,
Figure BDA00033641535500000710
i.e. the identification value that needs to be updated at the current moment.
Further, step S6 specifically includes:
1) Calculating the SOC of the target lithium ion battery by using the measured data based on an ampere-hour integration method, and determining the dOCV/dQ standard value at the current k moment by combining the relationship between the dOCV/dQ standard value obtained in the step S2 and the SOC;
2) And (4) time delay comparison is carried out on the dOCV/dQ calculated at the time k through the step S5 and the standard value of the time k-L/2 (in the embodiment, the time k-500), and whether the internal short circuit condition occurs or not is determined.
In the battery used in the preferred embodiment, the detection is performed only in the battery normal section of 10-93% soc, considering that the change in dcv/dQ in the 0-10% and 93-100% soc sections is too significant to be effective for the detection of internal short circuits.
Fig. 4 and fig. 5 show the verification results of the online detection stage of the method in this embodiment. In fig. 4, the battery normally operates under the DST and FUDS conditions, respectively, and it can be seen that the dcv/dQ tracking value calculated in step S5 is always closer to the reference value and is maintained within the threshold. In fig. 5, during the operation of the battery, the internal short circuit conditions of different degrees (i.e. different short circuit currents) are simulated in the form of external parallel equivalent loads; the results show that within a short time after the short circuit trigger, the dcv/dQ trace value calculated in step S5 deviates from the standard value and exceeds the threshold value to successfully detect an internal short circuit fault. Although to a lesser extent internal short-circuiting (I) SC The detection performance of = 5A) is degraded.
It should be understood that, the sequence numbers of the steps in the embodiments of the present invention do not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic of the process, and should not constitute any limitation on the implementation process of the embodiments of the present invention.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (4)

1. A method for detecting short circuit in a lithium ion battery unit is characterized by comprising the following steps: the method specifically comprises the following steps:
s1, carrying out a small-rate discharge test on a single battery, and respectively obtaining the relationship among the open-circuit voltage OCV, the discharge capacity Q and the state of charge SOC of the single battery;
s2, calculating a standard value of dOCV/dQ according to the relationship between the OCV and the Q obtained in the step S1;
s3, measuring voltage and current data of the target lithium ion battery in real time;
s4, 1) selecting one of a Rint model, a first-order RC model and a second-order RC model for the target lithium ion battery to establish an equivalent circuit model considering the internal short circuit condition;
2) And (3) utilizing the voltage and current data obtained by the measurement in the step (S3) and identifying model parameters on line based on a recursive least square method with forgetting factors:
Figure FDA0003730426860000011
in the formula, mu is a forgetting factor, and mu is more than 0.95 and less than 1;
Figure FDA0003730426860000012
in order to input the vector of data,
Figure FDA0003730426860000013
for the parameter vector to be identified, the superscript Λ represents the estimated value of the corresponding parameter,
Figure FDA0003730426860000014
is an output; k is LS,k For RLS gain, P LS,k Is a covariance matrix, I is an identity matrix, and k represents the current moment;
3) Calculating and identifying open-circuit voltage of equivalent circuit model
Figure FDA0003730426860000015
S5, aiming at the linear relation among the open-circuit voltage, the discharge capacity and the dOCV/dQ, the open-circuit voltage identified in the step S4 and the measured accumulated discharge capacity are utilized, and the dOCV/dQ value is updated and calculated in real time based on a recursive least square method and a limited memory recursive least square method, wherein the specific process comprises the following steps of:
1) Setting the length L of a memory window;
2) Using linear equations
Figure FDA0003730426860000016
Describes the linear relationship among the open-circuit voltage, the discharge capacity and dOCV/dQ, where y k =U OCV,k
Figure FDA0003730426860000017
Q Ah,k For the accumulated discharge capacity obtained by ampere-hour integration, the parameter vector theta = [ alpha beta ]] T Where the term α is dOCV/dQ, and subscript k denotes the current time;
3) Using calculation
Figure FDA0003730426860000018
And Q Ah,k When k is less than or equal to L, updating the parameter vector theta by adopting a recursive least square method, as shown in the following formula:
Figure FDA0003730426860000019
when k is larger than L, updating the parameter vector theta by using a finite memory recursive least square method, wherein the method comprises the following two processes:
1) New data was introduced as shown by the following formula:
Figure FDA0003730426860000021
in the formula, P LS,k-L,k-1 And
Figure FDA0003730426860000022
respectively representing a covariance matrix and a parameter vector estimation value formed by L groups of measurement data from k-L to k-1; p LS,k-L,k And
Figure FDA0003730426860000023
then respectively represent the total of L +1 sets of measurements from k-L to kMeasuring a covariance matrix and a parameter vector estimation value formed by data; k LS,k-L,k Is the gain;
2) Culling old data, as shown in the following equation:
Figure FDA0003730426860000024
in the formula, P LS,k-L+1,k And
Figure FDA0003730426860000025
respectively representing covariance matrix and parameter vector estimated value formed by L groups of measurement data from k-L +1 to k moments; k LS,k-L+1,k In order to achieve the gain,
Figure FDA0003730426860000026
namely the identification value which needs to be updated at the current moment;
and S6, comparing the dOCV/dQ value obtained by calculation in the S5 with the OCV/dQ standard value obtained in the step S2, determining that an internal short-circuit fault occurs when the difference value of the dOCV/dQ value and the OCV/dQ standard value exceeds a preset threshold value, and returning to the S3 to continue to perform detection at the next moment if the difference value of the dOCV/dQ value and the OCV/dQ standard value exceeds the preset threshold value.
2. The method of claim 1, wherein: the specific process of the small-rate discharge test developed in the step S1 includes: firstly, charging a battery monomer to full charge electric quantity in a constant current and constant voltage mode, standing for more than 3 hours, and then discharging to lower cut-off voltage in a constant current mode at a multiplying power less than or equal to 1/20C; the open circuit voltage is equivalent by the terminal voltage in the discharging process; the discharge test also comprises the step of repeatedly carrying out the same battery monomer at different temperatures respectively so as to obtain the open-circuit voltage of the battery at different temperatures; the relationship between the discharge capacity Q and the state of charge SOC is calculated by an ampere-hour integration method.
3. The method of claim 2, wherein: the calculation method for calculating the standard value of dcv/dQ in step S2 includes the following steps:
1) Taking the discharge capacity Q as an independent variable and the open-circuit voltage OCV as a dependent variable, and solving corresponding derivatives under different independent variables to obtain a corresponding dOCV/dQ standard value;
2) According to the total capacity of the battery and the relation between the open-circuit voltage OCV and the SOC, sampling and derivation are carried out by adopting a spline, and a dOCV/dQ standard value result is converted;
the calculation of the standard value of the dOCV/dQ comprises the calculation for different temperature conditions.
4. The method of claim 1, wherein: step S6 specifically includes:
1) Calculating the SOC of the target lithium ion battery by using the measured data based on an ampere-hour integration method, and determining the dOCV/dQ standard value at the current k moment by combining the relationship between the dOCV/dQ standard value obtained in the step S2 and the SOC;
2) And D, comparing the time k of dOCV/dQ calculated in the step S5 with the standard value of the time k-L/2 in a delayed manner, and determining whether the internal short circuit condition occurs.
CN202111399433.5A 2021-11-19 2021-11-19 Method for detecting short circuit in lithium ion battery unit Active CN114152826B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111399433.5A CN114152826B (en) 2021-11-19 2021-11-19 Method for detecting short circuit in lithium ion battery unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111399433.5A CN114152826B (en) 2021-11-19 2021-11-19 Method for detecting short circuit in lithium ion battery unit

Publications (2)

Publication Number Publication Date
CN114152826A CN114152826A (en) 2022-03-08
CN114152826B true CN114152826B (en) 2022-11-18

Family

ID=80457423

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111399433.5A Active CN114152826B (en) 2021-11-19 2021-11-19 Method for detecting short circuit in lithium ion battery unit

Country Status (1)

Country Link
CN (1) CN114152826B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116482551B (en) * 2023-04-26 2024-03-29 上海玫克生储能科技有限公司 Calibration method, measurement method, system, equipment and medium for short circuit in module

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11121049A (en) * 1997-10-17 1999-04-30 Japan Storage Battery Co Ltd Capacity estimating method for lead-acid battery
WO2011108175A1 (en) * 2010-03-02 2011-09-09 新神戸電機株式会社 Lead storage battery
DE102014209463A1 (en) * 2014-05-19 2015-11-19 Robert Bosch Gmbh Detection of internal short circuits in battery cells
CN105277898B (en) * 2015-10-27 2018-07-10 浙江大学 A kind of detection method of battery charge state
WO2018124721A1 (en) * 2016-12-27 2018-07-05 Samsung Electronics Co., Ltd. Method and electronic device for detecting internal short circuit in battery
US9774197B1 (en) * 2017-02-22 2017-09-26 Bordrin Motor Corporation, Inc. Battery internal short-circuit detection method based on cell charge balancing
CN106802396B (en) * 2017-03-28 2019-04-05 上海理工大学 A kind of diagnostic method of battery internal short-circuit
CN110506215A (en) * 2017-04-26 2019-11-26 华为技术有限公司 A kind of method and device of determining battery internal short-circuit
CN108226693B (en) * 2017-12-18 2020-02-07 清华大学 Method and apparatus for detecting short circuit in battery in real time, and computer-readable storage medium
CN108562855B (en) * 2017-12-18 2020-02-07 清华大学 Method and device for detecting short circuit in battery and computer readable storage medium
US11355824B2 (en) * 2018-05-11 2022-06-07 The Regents Of The University Of Michigan Detection of an internal short circuit in a battery
WO2019229651A1 (en) * 2018-05-28 2019-12-05 Yazami Ip Pte. Ltd. Method and system for detecting internal short‐circuit (isc) in batteries and battery cells implementing such isc detection method
KR20210080069A (en) * 2019-12-20 2021-06-30 주식회사 엘지에너지솔루션 Apparatus and method for diagnosing battery
CN111198326B (en) * 2020-02-19 2021-05-04 北京理工大学 Battery monomer short-circuit resistance online detection method with anti-disturbance characteristic
CN111198327B (en) * 2020-02-24 2021-02-02 北京理工大学 Self-detection method for short circuit fault in single battery

Also Published As

Publication number Publication date
CN114152826A (en) 2022-03-08

Similar Documents

Publication Publication Date Title
CN111198327B (en) Self-detection method for short circuit fault in single battery
CN111610456B (en) Diagnostic method for distinguishing micro short circuit and small-capacity fault of battery
Chen et al. Battery state of charge estimation based on a combined model of Extended Kalman Filter and neural networks
JP5818878B2 (en) Lithium ion battery charge state calculation method
CN111551860B (en) Battery internal short circuit diagnosis method based on relaxation voltage characteristics
Seo et al. Online detection of soft internal short circuit in lithium-ion batteries at various standard charging ranges
CN110031777B (en) Method for quickly obtaining resistance values of all single batteries in battery pack
JP7030191B2 (en) Methods and devices for monitoring the stable convergence behavior of the Kalman filter
CN106126783B (en) A kind of lithium ion battery change time scale model parameter estimation method
CN111856282B (en) Vehicle-mounted lithium battery state estimation method based on improved genetic unscented Kalman filtering
Qiu et al. Battery hysteresis modeling for state of charge estimation based on Extended Kalman Filter
CN111781503A (en) Lithium ion energy storage battery SOC online estimation method
CN111929602A (en) Single battery leakage or micro short circuit quantitative diagnosis method based on capacity estimation
CN115792638A (en) SOC-internal short circuit joint estimation method based on battery model parameter identification
CN115494400B (en) Lithium battery lithium separation state online monitoring method based on ensemble learning
CN114152826B (en) Method for detecting short circuit in lithium ion battery unit
Ahmed et al. A scaling approach for improved open circuit voltage modeling in Li-ion batteries
CN115327415A (en) Lithium battery SOC estimation method based on limited memory recursive least square algorithm
CN114740385A (en) Self-adaptive lithium ion battery state of charge estimation method
Xiong et al. State-of-charge estimation for onboard LiFePO4 batteries with adaptive state update in specific open-circuit-voltage ranges
Bhattacharyya et al. On‐road estimation of state of charge of lithium‐ion battery by extended and dual extended Kalman filter considering sensor bias
Chen et al. Estimation of state of charge for lithium-ion battery considering effect of aging and temperature
CN112009252B (en) Fault diagnosis and fault-tolerant control method for power battery system
CN116184248B (en) Method for detecting tiny short circuit fault of series battery pack
Tang et al. An aging-and load-insensitive method for quantitatively detecting the battery internal-short-circuit resistance

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant