CN113884922A - Battery internal short circuit quantitative diagnosis method based on voltage and electric quantity outlier coefficient - Google Patents

Battery internal short circuit quantitative diagnosis method based on voltage and electric quantity outlier coefficient Download PDF

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CN113884922A
CN113884922A CN202111260301.4A CN202111260301A CN113884922A CN 113884922 A CN113884922 A CN 113884922A CN 202111260301 A CN202111260301 A CN 202111260301A CN 113884922 A CN113884922 A CN 113884922A
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voltage
charging process
battery
short circuit
outlier
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CN113884922B (en
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魏学哲
乔冬冬
戴海峰
范文君
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Tongji University
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Abstract

The invention relates to a method for quantitatively diagnosing a short circuit in a battery based on voltage and electric quantity outliers, which comprises the following steps: 1) acquiring voltage, current and charging time data of each single battery in the charging process of the power battery on line; 2) respectively calculating a voltage outlier coefficient and an electric quantity outlier coefficient of each single battery in each cyclic charging process; 3) determining whether the power battery has an internal short circuit or not based on the voltage outlier coefficient and the electric quantity outlier coefficient, and positioning the single battery with the internal short circuit; 4) and quantitatively calculating the short-circuit resistance value of the single battery with the internal short circuit. Compared with the prior art, the method has the advantages of simple and convenient implementation, short diagnosis time, high diagnosis accuracy and the like.

Description

Battery internal short circuit quantitative diagnosis method based on voltage and electric quantity outlier coefficient
Technical Field
The invention relates to the technical field of energy storage batteries, in particular to a battery internal short circuit quantitative diagnosis method based on voltage and electric quantity outlier coefficients.
Background
The lithium ion battery is used as a core component of a new energy electric automobile, has the advantages of high energy density, long cycle life, no memory effect, low self-discharge rate and the like, and is widely concerned by people. However, lithium ion batteries have potential safety problems, and in recent years, many lithium ion battery safety accidents have occurred. The internal short circuit is one of the main reasons for causing the safety accidents of the lithium ion battery, the early internal short circuit symptoms are not obvious, but the continuous evolution can cause thermal runaway, so that the battery burns and even explodes. Therefore, the internal short circuit fault is detected as early as possible, and the method has important significance for improving the safety of the battery.
The existing internal short circuit detection methods comprise the following 4 methods: 1) a model-based diagnostic method. And judging whether the internal short circuit occurs or not by judging whether the error between the actual value of the parameters such as the voltage and the temperature measured by the battery and the predicted value of the battery model exceeds a threshold value or not. However, the modeling process of the method is complex and needs to be tested and verified for many times. 2) And detecting the change of voltage and temperature. And detecting whether the change rate of the battery voltage and the temperature exceeds a threshold set by a system so as to judge whether the internal short circuit occurs. However, the method is mainly suitable for the end stage of the internal short circuit, and the early characteristics of the internal short circuit cannot be accurately detected. 3) A method for detecting whether self-discharge occurs. Whether the self-discharge phenomenon of the battery exceeds the normal range is detected to judge whether the internal short circuit occurs. The method requires monitoring by a sensor or a series ammeter, increasing the cost of the battery pack. 4) Alternating current impedance method. And judging whether the battery has an internal short circuit or not by comparing the alternating current impedance spectrum of the battery to be detected with the alternating current impedance spectrum of the normal battery. However, the method has high technical difficulty and high cost, and the internal short circuit resistance value cannot be calculated quantitatively.
Disclosure of Invention
The present invention is directed to overcoming the above-mentioned drawbacks of the prior art and providing a method for quantitatively diagnosing a short circuit in a battery based on voltage and capacity outliers.
The purpose of the invention can be realized by the following technical scheme:
a method for quantitatively diagnosing a short circuit in a battery based on voltage and charge outliers, the method comprising:
1) acquiring voltage, current and charging time data of each single battery in the charging process of the power battery on line;
2) respectively calculating a voltage outlier coefficient and an electric quantity outlier coefficient of each single battery in each cyclic charging process;
3) determining whether the power battery has an internal short circuit or not based on the voltage outlier coefficient and the electric quantity outlier coefficient, and positioning the single battery with the internal short circuit;
4) and quantitatively calculating the short-circuit resistance value of the single battery with the internal short circuit.
Preferably, the voltage outlier in step 2) is obtained by the following formula:
Figure BDA0003325434610000021
wherein u isi(n1) Is n th1The voltage outlier coefficient of the ith single battery in the cyclic charging process, t is the charging time, t0(n1) Is n th1Starting time of a cyclic charging process, ts(n1) Is n th1The end time of the charge-up process of each cycle,
Figure BDA0003325434610000022
is n th1The voltage of the ith single battery at the moment t in the charging process of each cycle,
Figure BDA0003325434610000023
is n th1The average cell voltage at time t during a cycle of charging,
Figure BDA0003325434610000024
is n th1The maximum cell voltage at time t during each cycle of charging,
Figure BDA0003325434610000025
is n th1Minimum cell voltage at time t during each cycle of charging.
Preferably, the electric quantity outlier is obtained by the following method:
firstly, determining a charging voltage window of each cycle charging process;
then, calculating the charging electric quantity of each single battery in a voltage window in each cycle charging process;
and finally, calculating the electric quantity outlier coefficient of each single battery in each cycle charging process.
Preferably, the charging voltage window is determined by:
Figure BDA0003325434610000026
Figure BDA0003325434610000027
in the formula of Ulb(n2) Is n th2Lower limit voltage of voltage window in cyclic charging process, Uub(n2) Is n th2The upper limit voltage of the voltage window in the charging process of each cycle,
Figure BDA0003325434610000028
is n th2The maximum cell voltage after a time delay of delta t duration after the start of the cyclic charging process,
Figure BDA0003325434610000029
is n th2Minimum cell voltage at the end of the cyclic charging process, t0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2The termination time of each cyclic charging process.
Preferably, the charge capacity of each single battery in the voltage window during the cyclic charging process is calculated by the following formula:
Figure BDA0003325434610000031
wherein Q isj(n2) Is n th2The charging capacity of the jth single battery in the cyclic charging process,
Figure BDA0003325434610000032
is n th2And charging current of the jth single battery at the moment t in the cyclic charging process.
Preferably, the electric quantity outlier is calculated by the following formula:
Figure BDA0003325434610000033
in the formula, qj(n2) Is n th2The electric quantity outlier coefficient of the jth single battery in the cyclic charging process,
Figure BDA0003325434610000034
is n th2Average monomer charge capacity, Q, in a cyclic charging processmax(n2) Is n th2Maximum monomer charge capacity, Q, in a cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity in the cyclic charging process.
Preferably, step 3) is specifically:
31) if the ith single battery is at the nth1Voltage outlier u during cyclic chargingi(n1) Less than 0, and ui(n1) And n is1-m1Voltage outlier u during cyclic chargingi(n1-m1) Satisfies u (n)1-m1)-u(n1) If the voltage is more than or equal to g, preliminarily judging that the power battery has internal short circuit, wherein g is a constant more than 0;
32) if the jth single battery is at the nth2Electric quantity outlier q in cyclic charging processj(n2) Greater than 0, and qj(n2) And n is2-m2Electric quantity outlier coefficient q in cyclic charging processj(n2-m2) Satisfy q (n)2-m2)-q(n2) If the internal short circuit is not more than h, preliminarily judging that the power battery has an internal short circuit, wherein h is a constant more than 0;
33) if i is j, n is satisfied simultaneously1＝n2、m1＝m2And judging that the ith single battery in the power battery is an internal short circuit battery.
Preferably, let n be2If the jth single battery has an internal short circuit in the cyclic charging process, the short circuit resistance value of the single battery with the internal short circuit in the step 4) is calculated according to the following formula:
Figure BDA0003325434610000035
Figure BDA0003325434610000036
wherein, IISCr(n2) Is n th2Leakage current value, t, during each cycle of charging0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2End time of the cyclic charging process, Δ t being n2Time delay, delta Q, after the start of a cyclic charging processISCr(n2) For the jth single battery at [ t0(n2)+Δt]～ts(n2) Total leakage, Q, in a voltage windowj(n2) Is n th2The charge capacity, Q, of the jth cell in the cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity, R, in a cyclic charging processISCr(n2) Is n th2Resistance value of internal short-circuit resistor in cyclic charging processj(n2) Is n th2The resistance value of the internal short circuit resistor of the jth single battery in the charging process of each cycle,
Figure BDA0003325434610000041
is n th2The jth monomer is in [ t ] in the cyclic charging process0(n2)+Δt]～ts(n2) Average voltage within the voltage window.
Preferably, the constant g takes the values: g is more than or equal to 0.55 and less than or equal to 0.65.
Preferably, the constant h takes the value: h is more than or equal to 0.5 and less than or equal to 0.85.
Compared with the prior art, the invention has the following advantages:
(1) the method utilizes the voltage and electric quantity outlier coefficient to carry out internal short circuit judgment and short circuit resistance value quantitative calculation, can simply and accurately diagnose the battery frequently in the charging process on line, and can effectively ensure the safety of the electric automobile.
(2) The invention has simple and convenient implementation, short diagnosis time and high diagnosis accuracy.
Drawings
FIG. 1 is a block flow diagram of a method for quantitatively diagnosing a short circuit in a battery based on voltage and capacity outliers in accordance with the present invention;
FIG. 2 is a voltage-time curve of each cell in an embodiment of the present invention;
FIG. 3 is a graph of voltage outliers versus cycle number for each cell in an embodiment of the present disclosure;
FIG. 4 is a graph of the charge capacity versus the cycle number of each battery cell in an embodiment of the present invention;
fig. 5 is a graph of the charge outlier versus the cycle number of each cell in the embodiment of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to be limited to the application or the use thereof, and is not limited to the following embodiments.
Examples
As shown in fig. 1, the present embodiment provides a method for quantitatively diagnosing a short circuit in a battery based on voltage and capacity outlier, the method comprising:
1) and acquiring the voltage, current and charging time data of each single battery in the charging process of the power battery on line.
2) And respectively calculating the voltage outlier coefficient and the electric quantity outlier coefficient of each single battery in each cyclic charging process.
Wherein the voltage outlier is obtained by:
Figure BDA0003325434610000051
wherein u isi(n1) Is n th1The voltage outlier coefficient of the ith single battery in the cyclic charging process, t is the charging time, t0(n1) Is n th1Starting time of a cyclic charging process, ts(n1) Is n th1The end time of the charge-up process of each cycle,
Figure BDA0003325434610000052
is n th1The voltage of the ith single battery at the moment t in the charging process of each cycle,
Figure BDA0003325434610000053
is n th1The average cell voltage at time t during a cycle of charging,
Figure BDA0003325434610000054
is n th1The maximum cell voltage at time t during each cycle of charging,
Figure BDA0003325434610000055
is n th1Minimum cell voltage at time t during each cycle of charging.
The electric quantity outlier coefficient is obtained by the following method:
firstly, determining a charging voltage window of each cycle charging process;
then, calculating the charging electric quantity of each single battery in a voltage window in each cycle charging process;
and finally, calculating the electric quantity outlier coefficient of each single battery in each cycle charging process.
The charging voltage window is determined by:
Figure BDA0003325434610000056
Figure BDA0003325434610000057
in the formula of Ulb(n2) Is n th2Lower limit voltage of voltage window in cyclic charging process, Uub(n2) Is n th2The upper limit voltage of the voltage window in the charging process of each cycle,
Figure BDA0003325434610000058
is n th2The maximum cell voltage after a time delay of delta t duration after the start of the cyclic charging process,
Figure BDA0003325434610000059
is n th2Minimum cell voltage at the end of the cyclic charging process, t0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2The termination time of each cyclic charging process.
The charge capacity of each single battery in the voltage window in the cyclic charging process is calculated by the following formula:
Figure BDA00033254346100000510
wherein Q isj(n2) Is n th2The charging capacity of the jth single battery in the cyclic charging process,
Figure BDA00033254346100000511
is n th2And charging current of the jth single battery at the moment t in the cyclic charging process.
The charge outlier is calculated by the following equation:
Figure BDA00033254346100000512
in the formula, qj(n2) Is n th2The electric quantity outlier coefficient of the jth single battery in the cyclic charging process,
Figure BDA00033254346100000513
is n th2Average monomer charge capacity, Q, in a cyclic charging processmax(n2) Is n th2Maximum monomer charge capacity, Q, in a cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity in the cyclic charging process.
3) Whether the power battery has an internal short circuit or not is determined based on the voltage outlier coefficient and the electric quantity outlier coefficient, and the single battery with the internal short circuit is positioned, specifically:
31) if the ith single battery is at the nth1Voltage outlier u during cyclic chargingi(n1) Less than 0, and ui(n1) And n is1-m1Voltage outlier u during cyclic chargingi(n1-m1) Satisfies u (n)1-m1)-u(n1) And if the constant g is more than or equal to g, preliminarily judging that the power battery has internal short circuit, wherein the constant g takes the value as follows: g is more than or equal to 0.55 and less than or equal to 0.65;
32) if the jth single battery is at the nth2Electric quantity outlier q in cyclic charging processj(n2) Greater than 0, and qj(n2) And n is2-m2Electric quantity outlier coefficient q in cyclic charging processj(n2-m2) Satisfy q (n)2-m2)-q(n2) H is not more than h, then preliminarily judge that the power battery has an internal short circuit, and the constant h takes the value as: h is more than or equal to 0.5 and less than or equal to 0.85;
33) if i is j, n is satisfied simultaneously1＝n2、m1＝m2And judging that the ith single battery in the power battery is an internal short circuit battery.
4) Quantitatively calculating the short circuit resistance value of the single battery with the internal short circuit, and assuming the nth2And if the jth single battery generates an internal short circuit in the cyclic charging process, calculating the short circuit resistance value of the single battery with the internal short circuit according to the following formula:
Figure BDA0003325434610000061
Figure BDA0003325434610000062
wherein, IISCr(n2) Is n th2Leakage current value, t, during each cycle of charging0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2End time of the cyclic charging process, Δ t being n2Time delay, delta Q, after the start of a cyclic charging processISCr(n2) For the jth single battery at [ t0(n2)+Δt]～ts(n2) Total leakage, Q, in a voltage windowj(n2) Is n th2The charge capacity, Q, of the jth cell in the cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity, R, in a cyclic charging processISCr(n2) Is n th2Resistance value of internal short-circuit resistor in cyclic charging processj(n2) Is n th2The resistance value of the internal short circuit resistor of the jth single battery in the charging process of each cycle,
Figure BDA0003325434610000063
is n th2The jth monomer is in [ t ] in the cyclic charging process0(n2)+Δt]～ts(n2) Average voltage within the voltage window.
The battery used in this embodiment is a ternary lithium ion battery, and the charge and discharge cutoff voltages are 4.2V and 2.5V, respectively, but not limited to this in practical application. In the experiment, a 1000-ohm resistor is externally connected to the battery 4 to simulate the internal short circuit of the battery.
1. And voltage data of the power battery in the charging process are collected on line, and a voltage outlier coefficient is calculated.
Because each single battery is connected in series, the working conditions are the same, and therefore, the voltage of each single battery is approximately the same for a healthy battery. When the ith single battery is at the nth1When the internal short circuit occurs in each cycle, the internal short circuit battery leaks at the internal short circuit position, so that the voltage of the internal short circuit battery is lower than that of other normal batteries, the more serious the short circuit of the monomer i is, the more obvious the electric leakage phenomenon is, namely the voltage
Figure BDA0003325434610000071
The smaller. The voltage-time curve of each cell is shown in fig. 2.
According to the online collected voltage data of the charging process of the power battery, calculating the voltage outlier coefficient of each single battery, wherein the voltage outlier coefficient of each single battery is the average value of the difference value of the single voltage and the average single voltage at each moment in a certain cyclic charging process divided by the voltage range, namely:
Figure BDA0003325434610000072
when the ith single battery is at the nth1When an internal short circuit occurs during the charging process of each cycle, the voltage of the ith battery is gradually reduced and is usually positioned at the lowest part of the charging voltage curve, so that the voltage of the ith battery is gradually reduced
Figure BDA0003325434610000073
During the charging process of the battery, although the voltage of each single battery is gradually increased, the voltage of each single battery is gradually increased
Figure BDA0003325434610000074
Increase less than
Figure BDA0003325434610000075
And due to
Figure BDA0003325434610000076
Thus, it is possible to provide
Figure BDA0003325434610000077
Is greater than
Figure BDA0003325434610000078
I.e., the internal short-circuited battery outlier is gradually reduced. Plotting voltage ionThe population coefficient-cycle number curve is shown in fig. 3.
2. And determining a charging voltage window and calculating the electric quantity outlier coefficient of each single battery in the voltage window.
In this embodiment, when the charging window is determined, the internal resistance influence of the initial 250s of the charging process is eliminated, that is, Δ t is set to 250s, the lower limit of the voltage window is the maximum cell voltage at Δ t seconds after the charging process starts, and the upper limit is the minimum cell voltage at the end of charging, that is:
Figure BDA0003325434610000079
Figure BDA00033254346100000710
in the formula of Ulb(n2) Is n th2Lower limit voltage of voltage window in cyclic charging process, Uub(n2) Is n th2The upper limit voltage of the voltage window in the charging process of each cycle,
Figure BDA00033254346100000711
is n th2The maximum cell voltage after a time delay of delta t duration after the start of the cyclic charging process,
Figure BDA00033254346100000712
is n th2Minimum cell voltage at the end of the cyclic charging process, t0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2The termination time of each cyclic charging process.
The charging capacity of each single battery in the voltage window is calculated by an ampere-hour integral method, namely:
Figure BDA00033254346100000713
wherein Q isj(n2) Is n th2The charging capacity of the jth single battery in the cyclic charging process,
Figure BDA00033254346100000714
is n th2And charging current of the jth single battery at the moment t in the cyclic charging process.
Because each single battery is connected in series and the working conditions are the same, the charging electric quantity of each single battery in the same voltage window is approximately the same when the normal battery pack is charged every time. But when the jth single battery is at the nth2When an internal short circuit occurs in a cyclic charging process, the jth single battery can self-discharge and additionally consume electric quantity, the larger the short circuit degree is, the larger the leakage quantity is, and the charging electric quantity Q isj(n2) The larger. The charge-cycle number curve of each cell is shown in fig. 4.
The electric quantity outlier coefficient is the charging electric quantity outlier coefficient of the single battery in the voltage window, and the electric quantity range is divided by the difference value between the single electric quantity and the average single electric quantity, namely:
Figure BDA0003325434610000081
in the formula, qj(n2) Is n th2The electric quantity outlier coefficient of the jth single battery in the cyclic charging process,
Figure BDA0003325434610000082
is n th2Average monomer charge capacity, Q, in a cyclic charging processmax(n2) Is n th2Maximum monomer charge capacity, Q, in a cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity in the cyclic charging process.
When the jth single battery is at the nth2When the internal short circuit occurs in each cycle, the charging capacity Q of the jth single batteryj(n2) The charged electric quantity of other single batteries is increased and larger, so that the single battery is in the nth state2Electric quantity outlier coefficient q of each cyclej(n2) The charge outlier-cycle curve is plotted as shown in fig. 5, which should be increased and larger than the charge outliers of other cells.
3. And comprehensively judging whether the power battery is internally short-circuited or not based on the voltage and electric quantity outlier coefficients.
In the present embodiment, the voltage outlier reduction threshold g is set to 0.6, and as can be seen from fig. 3 obtained in step 1, the charging voltage outlier u of the battery 4 at the 4 th cycle4(3) 0.691, coefficient u of charging voltage outlier of cycle 34(3) When the internal short circuit occurs, the internal short circuit is decreased by 0.809 compared with 0.118.
In this embodiment, the power outlier rising threshold h is set to 0.8, and as can be seen from fig. 5 obtained in step 2, the power outlier q of the battery 4 at the 3 rd cycle is set4(4) 0.721, and the power outlier q of the 35 th cycle4(3) The voltage was increased by 1.272 compared to-0.551, and the number 4 cell was judged to have an internal short circuit from the 4 th cycle in combination with the voltage outlier calculation result.
4. And calculating the short-circuit resistance value of the battery based on the charging electric quantity and the charging time of the internal short-circuit battery in the voltage window.
At the n-th2One cycle, the difference Δ Q between the charge of the shorted battery j and the minimum charge of the normal batteryISCr(n2) To short the total leakage of cell j within this voltage window, the total leakage is expressed as Δ QISCr(n2) Dividing the charging time of the battery in the voltage window to obtain the leakage current value I of the short-circuited batteryISCr(n2) I.e. by
Figure BDA0003325434610000083
Calculating the average voltage of the short-circuit battery j in the voltage window
Figure BDA0003325434610000084
Divided by short-circuit current IISCr(n2) The short-circuit resistance R can be obtainedISCr(n2) Namely:
Figure BDA0003325434610000085
the short-circuit resistance R of the battery 4 at the 4 th cycle in which the internal short-circuit occurs can be obtained by the above calculation stepISCr(4) 901.821 Ω, the error is 9.818%. The method can be used for quantitatively diagnosing the internal short circuit of the battery by quantitatively calculating the resistance value.
The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments may be implemented in other various manners, and various omissions, substitutions, and changes may be made without departing from the technical spirit of the present invention.

Claims (10)

1. A method for quantitatively diagnosing a short circuit in a battery based on voltage and capacity outliers, the method comprising:
1) acquiring voltage, current and charging time data of each single battery in the charging process of the power battery on line;
2) respectively calculating a voltage outlier coefficient and an electric quantity outlier coefficient of each single battery in each cyclic charging process;
3) determining whether the power battery has an internal short circuit or not based on the voltage outlier coefficient and the electric quantity outlier coefficient, and positioning the single battery with the internal short circuit;
4) and quantitatively calculating the short-circuit resistance value of the single battery with the internal short circuit.
2. The method for quantitatively diagnosing the short circuit in the battery based on the voltage and electric quantity outlier of claim 1, wherein the voltage outlier in the step 2) is obtained by the following formula:
Figure FDA0003325434600000011
wherein u isi(n1) Is n th1In the cyclic charging processVoltage outlier coefficient of i single batteries, t is charging time, t0(n1) Is n th1Starting time of a cyclic charging process, ts(n1) Is n th1The end time of the charge-up process of each cycle,
Figure FDA0003325434600000012
is n th1The voltage of the ith single battery at the moment t in the charging process of each cycle,
Figure FDA0003325434600000013
is n th1The average cell voltage at time t during a cycle of charging,
Figure FDA0003325434600000014
is n th1The maximum cell voltage at time t during each cycle of charging,
Figure FDA0003325434600000015
is n th1Minimum cell voltage at time t during each cycle of charging.
3. The method according to claim 1, wherein the battery short circuit quantitative diagnosis method based on the voltage and the electric quantity outlier is characterized in that the electric quantity outlier is obtained by the following method:
firstly, determining a charging voltage window of each cycle charging process;
then, calculating the charging electric quantity of each single battery in a voltage window in each cycle charging process;
and finally, calculating the electric quantity outlier coefficient of each single battery in each cycle charging process.
4. The method of claim 3, wherein the charging voltage window is determined by the following equation:
Figure FDA0003325434600000016
Figure FDA0003325434600000017
in the formula of Ulb(n2) Is n th2Lower limit voltage of voltage window in cyclic charging process, Uub(n2) Is n th2The upper limit voltage of the voltage window in the charging process of each cycle,
Figure FDA0003325434600000021
is n th2The maximum cell voltage after a time delay of delta t duration after the start of the cyclic charging process,
Figure FDA0003325434600000022
is n th2Minimum cell voltage at the end of the cyclic charging process, t0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2The termination time of each cyclic charging process.
5. The method as claimed in claim 4, wherein the charge capacity of each cell in the voltage window during the cyclic charging process is calculated by the following formula:
Figure FDA0003325434600000023
wherein Q isj(n2) Is n th2The charging capacity of the jth single battery in the cyclic charging process,
Figure FDA0003325434600000024
is n th2In the process of cyclic chargingAnd charging current of the jth single battery at the moment t.
6. The method of claim 5, wherein the battery short circuit quantitative diagnosis method is based on voltage and battery outlier, wherein the battery outlier is calculated by the following formula:
Figure FDA0003325434600000025
in the formula, qj(n2) Is n th2The electric quantity outlier coefficient of the jth single battery in the cyclic charging process,
Figure FDA0003325434600000026
is n th2Average monomer charge capacity, Q, in a cyclic charging processmax(n2) Is n th2Maximum monomer charge capacity, Q, in a cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity in the cyclic charging process.
7. The method for quantitatively diagnosing the short circuit in the battery based on the voltage and electric quantity outlier according to claim 1, wherein the step 3) is specifically as follows:
31) if the ith single battery is at the nth1Voltage outlier u during cyclic chargingi(n1) Less than 0, and ui(n1) And n is1-m1Voltage outlier u during cyclic chargingi(n1-m1) Satisfies u (n)1-m1)-u(n1) If the voltage is more than or equal to g, preliminarily judging that the power battery has internal short circuit, wherein g is a constant more than 0;
32) if the jth single battery is at the nth2Electric quantity outlier q in cyclic charging processj(n2) Greater than 0, and qj(n2) And n is2-m2Electric quantity outlier coefficient q in cyclic charging processj(n2-m2) Satisfy q (n)2-m2)-q(n2) If the internal short circuit is not more than h, preliminarily judging that the power battery has an internal short circuit, wherein h is a constant more than 0;
33) if i is j, n is satisfied simultaneously1＝n2、m1＝m2And judging that the ith single battery in the power battery is an internal short circuit battery.
8. The method of claim 1, wherein the nth method is assumed to be based on voltage and capacity outlier2If the jth single battery has an internal short circuit in the cyclic charging process, the short circuit resistance value of the single battery with the internal short circuit in the step 4) is calculated according to the following formula:
Figure FDA0003325434600000031
wherein, IISCr(n2) Is n th2Leakage current value, t, during each cycle of charging0(n2) Is n th2Starting time of a cyclic charging process, ts(n2) Is n th2End time of the cyclic charging process, Δ t being n2Time delay, delta Q, after the start of a cyclic charging processISCr(n2) For the jth single battery at [ t0(n2)+Δt]～ts(n2) Total leakage, Q, in a voltage windowj(n2) Is n th2The charge capacity, Q, of the jth cell in the cyclic charging processmin(n2) Is n th2Minimum monomer charge capacity, R, in a cyclic charging processISCr(n2) Is n th2Resistance value of internal short-circuit resistor in cyclic charging processj(n2) Is n th2The resistance value of the internal short circuit resistor of the jth single battery in the charging process of each cycle,
Figure FDA0003325434600000032
is n th2The jth monomer is in [ t ] in the cyclic charging process0(n2)+Δt]～ts(n2) Average voltage within the voltage window.
9. The method according to claim 7, wherein the constant g is a value selected from the group consisting of: g is more than or equal to 0.55 and less than or equal to 0.65.
10. The method according to claim 7, wherein the constant h is a value selected from the group consisting of: h is more than or equal to 0.5 and less than or equal to 0.85.
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