CN108693478A - A kind of method for detecting leakage of lithium-ion-power cell - Google Patents

A kind of method for detecting leakage of lithium-ion-power cell Download PDF

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Publication number
CN108693478A
CN108693478A CN201810341466.6A CN201810341466A CN108693478A CN 108693478 A CN108693478 A CN 108693478A CN 201810341466 A CN201810341466 A CN 201810341466A CN 108693478 A CN108693478 A CN 108693478A
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China
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leakage
battery
occurs
ion
lithium
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熊瑞
杨瑞鑫
陈泽宇
卢家欢
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Beijing Institute of Technology BIT
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Beijing Institute of Technology BIT
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Abstract

The present invention provides a kind of method for detecting leakage of lithium-ion-power cell, can accurately judge whether short trouble causes battery leakage in the case where not opening battery case observation.By establishing the battery model of external short circuit failure, and grader of the operation based on random forest method realizes joint leakage identification.This method is suitable for battery failures diagnostic system, can predict to provide foundation with diagnosis for the fault degree after battery short circuit, have many advantageous effects such as operation is simple, is easily achieved.

Description

A kind of method for detecting leakage of lithium-ion-power cell
Technical field
The present invention relates to cell safety technical field more particularly to a kind of method for detecting leakage of lithium-ion-power cell.
Background technology
External short circuit belongs to a kind of catastrophic discontinuityfailure most commonly seen in vehicle lithium-ion power battery failure, outside occurring In tens seconds after portion's short circuit, high temperature and high current caused by power battery, it is most likely that cause serious leakage, leak Electrolyte then can further cause the even more serious consequence including on fire, therefore power battery leakage is differentiated It is highly important.However, since vehicle lithium-ion power battery is usually disposed with battery case, by unpacking, observation battery is No leakage was both inconvenient or dangerous, and automobile-used lithium ion battery is often hundreds of batteries series, parallel composition battery packs, Dense arrangement between battery, even if observing that leakage is also difficult to realize positioning to the battery location of specific leakage.It can be seen that existing The leakage detection mode of some lithium-ion-power cells still has certain limitation, is not beaten even if this field urgent need is a kind of The method that leakage detects can be realized by opening battery case also.
Invention content
For technical problem present in above-mentioned this field, the present invention provides a kind of leakage of lithium-ion-power cell inspections Survey method, specifically includes following steps:
Step 1: carrying out multigroup external short circuit experiment, record current, voltage and temperature to different lithium-ion-power cells Data;
Step 2: battery model is established to lithium-ion-power cell, and based on the data recorded in the step 1 Parameter identification is carried out to the battery model, and determines and short trouble state threshold and generation leakage state threshold occurs;
Step 3: inline diagnosis is carried out to failure using the battery model established in step 2, and according to power battery Data judge it and short trouble state occur and the goodness of fit of leakage state occurs;
Step 4: the grader based on random forests algorithm is established, and according to the data recorded in the step 1 The grader is trained, is realized to short trouble state occurs and the monitoring of leakage state occurs.
Step 5: combine the battery model and it is described based on the grader of random forests algorithm to whether leakage occurring It is detected.
Further, the step 2 specifically includes:
The battery model established uses fractional order impedance model, utilizes electric current, voltage and the temperature when not occurring leakage Degrees of data is trained the model, to establish out the electricity that can simulate non-leakage state lower outer portion short circuit electrical property change Pool model;Parameter identification is carried out to the fractional order impedance model based on genetic algorithm.
Further, failure progress inline diagnosis is specifically included described in the step 3:
The voltage that practical power battery voltage and the fractional order impedance model export under short trouble state is carried out Compare, calculates since short circuit to the goodness of fit χ in the period at current time:
VmFor model prediction terminal voltage, V is the practical terminal voltage of battery, and n is data length.
The generation short trouble state threshold δ that will be determined in the goodness of fit χ and the step 21And it leaks Liquid status threshold value δ2It is compared.
Further, the grader based on random forests algorithm and its training process established in the step 4 are specific Including:
4.1, after acquisition short circuit occurs in M lithium-ion-power cell sample leakage battery and non-leakage battery it is maximum warm Liter and discharge capacity statistical data, are input to as total training dataset in random forests algorithm;
4.2, resampling is carried out using Bootstrap methods, randomly generates N number of training dataset S1,S2,…,SN.Wherein, Si(1≤i≤N) is the data set that ith has the extraction put back to be formed from M battery sample data;
4.3, it is based on generated N number of training dataset and generates N decision tree at random respectively, after every decision tree is trained to Grasp the classification capacity for judging whether that leakage occurs by maximum temperature rise and discharge capacity data.
Further, the joint fractional order impedance model described in the step 5 and described it is based on random forest The grader of algorithm is detected, and is specifically included:
5.1, according to goodness of fit χ and the generation short trouble state threshold δ1And leakage state threshold δ occurs2Ratio Relatively result is judged, if χ > δ2, it is believed that leakage, assignment K1=0 does not occur;If δ1<χ<δ2, then it is assumed that leakage occurs, assigns Value K=1;
5.2, run the grader based on random forests algorithm, by collected lithium-ion-power cell maximum temperature rise with put Electricity is input to as test data set X in trained each decision tree, exports leakage monitoring state K2, when generation leakage When assignment K2=1;
5.3, when K1 and K2 are simultaneously 1, assignment K=1 indicates that leakage occurs for battery, otherwise K=0, and expression is not leaked Liquid.
It, being capable of the accurately judgement short circuit in the case where not opening battery case observation according to the above method provided by the present invention Whether failure causes battery leakage.By establishing the battery model of external short circuit failure, and operation based on random forest side The grader of method realizes joint leakage identification.This method is suitable for battery failures diagnostic system, can be for after battery short circuit Fault degree predicts to provide foundation with diagnosis have many advantageous effects such as operation is simple, is easily achieved.
Description of the drawings
Fig. 1 is the flow diagram according to method provided by the present invention
Fig. 2 is the schematic diagram of lithium-ion-power cell fractional order impedance model
Fig. 3 is that power battery terminal voltage predicted value changes over time pass with measured value in a specific example according to the present invention It is (SoC=20%)
Fig. 4 is that power battery terminal voltage predicted value changes over time pass with measured value in a specific example according to the present invention It is (SoC=60%)
Fig. 5 is that power battery terminal voltage predicted value changes over time pass with measured value in a specific example according to the present invention It is (SoC=100%)
Fig. 6 is the grader schematic diagram based on random forests algorithm
Fig. 7 is that leakage detection differentiates result
Specific implementation mode
Below in conjunction with the accompanying drawings to the technical solution of the method for detecting leakage of lithium-ion-power cell provided by the present invention, do Go out and further illustrates in detail.
As shown in Figure 1, method provided by the present invention specifically includes following steps:
Step 1: carrying out multigroup external short circuit experiment, record current, voltage and temperature to different lithium-ion-power cells Data;
Step 2: fractional order impedance model is established to lithium-ion-power cell, and based on the institute recorded in the step 1 It states data and parameter identification is carried out to the fractional order impedance model, and determine and short trouble state threshold and generation leakage occurs State threshold;
Step 3: inline diagnosis is carried out to failure using the fractional order impedance model established in step 2, and according to dynamic Power battery data judges it and short trouble state occurs and the goodness of fit of leakage state occurs;
Step 4: the grader based on random forests algorithm is established, and according to the data recorded in the step 1 The grader is trained, is realized to short trouble state occurs and the monitoring of leakage state occurs.
Step 5: combine the fractional order impedance model and it is described based on the grader of random forests algorithm to whether sending out Raw leakage is detected.
In the preferred embodiment of the application, the step 2 specifically includes:
The fractional order impedance model established uses fractional order impedance model, as shown in Fig. 2, V in figureocvFor open-circuit voltage, RoFor ohmic internal resistance, RctFor electric charge transfer internal resistance, CPE is normal phase angle original paper, and W is weber impedance.When using leakage not occurring Electric current, voltage and temperature data the model is trained, it is initial for basic, normal, high three kinds under room temperature (20 DEG C) SoC (20%, 60% and 100%) is carried out, and tests 1 battery cell under identical conditions respectively, and 3 battery cells of record were tested Cell voltage in journey and curent change, this 3 monomers are without occurring the phenomenon of leakage.Non- leakage can be simulated to establish out The battery model of state lower outer portion short circuit electrical property change;Parameter is carried out based on genetic algorithm to the fractional order impedance model to distinguish Know.Power battery terminal voltage prediction result and actual measurement terminal voltage result are as in Figure 3-5.Error mean square root is as listed in table 1.
Table 1
In the preferred embodiment of the application, failure progress inline diagnosis is specifically wrapped described in the step 3 It includes:
The voltage that practical power battery voltage and the fractional order impedance model export under short trouble state is carried out Compare, calculates since short circuit to the goodness of fit χ in the period at current time:
VmFor model prediction terminal voltage, V is the practical terminal voltage of battery, and n is data length.
The generation short trouble state threshold δ that will be determined in the goodness of fit χ and the step 21And it leaks Liquid status threshold value δ2It is compared.Optionally 3 initial SoC are respectively that 20%, 60% and 100% battery carries out external short circuit reality It tests, note electric current, voltage and temperature data.Using the first step trained model prediction external short circuit failure behavior, obtain Preceding 2s inner terminal voltages predicted value and measured value root-mean-square error, as shown in table 2.
Table 2
In the preferred embodiment of the application, as shown in fig. 6, established in the step 4 based on random forest The grader and its training process of algorithm specifically include:
4.1, after acquisition short circuit occurs in M lithium-ion-power cell sample leakage battery and non-leakage battery it is maximum warm Liter and discharge capacity statistical data, are input to as total training dataset in random forests algorithm;
4.2, resampling is carried out using Bootstrap methods, randomly generates N number of training dataset S1,S2,…,SN.Wherein, Si(1≤i≤N) is the data set that ith has the extraction put back to be formed from M battery sample data;
4.3, it is based on generated N number of training dataset and generates N decision tree at random respectively, after every decision tree is trained to Grasp the classification capacity for judging whether that leakage occurs by maximum temperature rise and discharge capacity data.
In the preferred embodiment of the application, the joint fractional order impedance model described in the step 5 with And the grader based on random forests algorithm is detected, and is specifically included:
5.1, according to goodness of fit χ and the generation short trouble state threshold δ1And leakage state threshold δ occurs2Ratio Relatively result is judged, if χ > δ2, it is believed that leakage, assignment K1=0 does not occur;If δ1<χ<δ2, then it is assumed that leakage occurs, assigns Value K=1;
5.2, run the grader based on random forests algorithm, by collected lithium-ion-power cell maximum temperature rise with put Electricity is input to as test data set X in trained each decision tree, exports leakage monitoring state K2, when generation leakage When assignment K2=1;
5.3, when K1 and K2 are simultaneously 1, assignment K=1 indicates that leakage occurs for battery, otherwise K=0, and expression is not leaked Liquid.
In the case that known SoC is 100% from the experiment of this case verification, leakage occurs for battery, using patent of the present invention Last differentiates that result is also coincide with practical to leakage, and classification tree number is as shown in Fig. 7.
It although an embodiment of the present invention has been shown and described, for the ordinary skill in the art, can be with Understanding without departing from the principles and spirit of the present invention can carry out these embodiments a variety of variations, modification, replace And modification, the scope of the present invention is defined by the appended.

Claims (5)

1. a kind of method for detecting leakage of lithium-ion-power cell, it is characterised in that:Specifically include following steps:
Step 1: carrying out multigroup external short circuit experiment, record current, voltage and temperature number to different lithium-ion-power cells According to;
Step 2: battery model is established to lithium-ion-power cell, and based on the data recorded in the step 1 to institute It states battery model and carries out parameter identification, and determine and short trouble state threshold and generation leakage state threshold occurs;
Step 3: inline diagnosis is carried out to failure using the battery model established in step 2, and according to power battery data Judge it and short trouble state occurs and the goodness of fit of leakage state occurs;
Step 4: the grader based on random forests algorithm is established, and according to the data recorded in the step 1 to institute It states grader to be trained, realize to short trouble state occurs and the monitoring of leakage state occurs.
Step 5: combine the battery model and it is described based on the grader of random forests algorithm to whether occur leakage carry out Detection.
2. the method as described in claim 1, it is characterised in that:The step 2 specifically includes:
The battery model established uses fractional order impedance model, utilizes electric current, voltage and the temperature number when not occurring leakage It is trained according to the model, to establish out the battery mould that can simulate non-leakage state lower outer portion short circuit electrical property change Type;Parameter identification is carried out to the fractional order impedance model based on genetic algorithm.
3. method as claimed in claim 2, it is characterised in that:It is specific to failure progress inline diagnosis described in the step 3 Including:
Practical power battery voltage is compared with the voltage that the fractional order impedance model exports under short trouble state, It calculates since short circuit to the goodness of fit χ in the period at current time:
VmFor model prediction terminal voltage, V is the practical terminal voltage of battery, and n is data length.
The generation short trouble state threshold δ that will be determined in the goodness of fit χ and the step 21And leakage shape occurs State threshold value δ2It is compared.
4. the method as described in claim 1, it is characterised in that:Established in the step 4 based on random forests algorithm Grader and its training process specifically include:
4.1, after acquisition short circuit occurs in M lithium-ion-power cell sample the maximum temperature rise of leakage battery and non-leakage battery and Discharge capacity statistical data is input to as total training dataset in random forests algorithm;
4.2, resampling is carried out using Bootstrap methods, randomly generates N number of training dataset S1,S2,…,SN.Wherein, Si(1 ≤ i≤N) it is the data set that ith has the extraction put back to be formed from M battery sample data;
4.3, it is based on generated N number of training dataset and generates N decision tree at random respectively, every decision tree is grasped after being trained to Judge whether the classification capacity of generation leakage by maximum temperature rise and discharge capacity data.
5. method as claimed in claim 3, it is characterised in that:The joint fractional order modulus of impedance described in the step 5 Type and the grader based on random forests algorithm are detected, and are specifically included:
5.1, according to goodness of fit χ and the generation short trouble state threshold δ1And leakage state threshold δ occurs2Comparison knot Fruit is judged, if χ > δ2, it is believed that leakage, assignment K1=0 does not occur;If δ1<χ<δ2, then it is assumed that leakage, assignment K=occurs 1;
5.2, the grader based on random forests algorithm is run, by collected lithium-ion-power cell maximum temperature rise and discharge capacity It is input in trained each decision tree as test data set X, exports leakage monitoring state K2, assigned when leakage occurs Value K2=1;
5.3, when K1 and K2 are simultaneously 1, assignment K=1 indicates that leakage occurs for battery, otherwise K=0, and leakage does not occur for expression.
CN201810341466.6A 2018-04-17 2018-04-17 A kind of method for detecting leakage of lithium-ion-power cell Pending CN108693478A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109657720A (en) * 2018-12-20 2019-04-19 浙江大学 A kind of inline diagnosis method of power transformer shorted-turn fault
WO2020155233A1 (en) * 2019-01-28 2020-08-06 东北大学 Method for diagnosing external short circuit fault of lithium-ion battery pack on basis of two-stage model prediction
CN111537913A (en) * 2020-05-14 2020-08-14 广东汉力威技术有限公司 Method for diagnosing short circuit by using pre-discharge loop
CN116429339A (en) * 2023-06-07 2023-07-14 海斯坦普汽车组件(北京)有限公司 Leakage detection method and system for new energy battery box

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CN106168799A (en) * 2016-06-30 2016-11-30 常伟 A kind of method carrying out batteries of electric automobile predictive maintenance based on big data machine learning
CN106526493A (en) * 2016-11-01 2017-03-22 北京理工大学 Power battery external short circuit fault diagnosing and temperature rise prediction method and system based on BP neural networks
CN106980091A (en) * 2017-03-29 2017-07-25 北京理工大学 A kind of electrokinetic cell system health status method of estimation based on fractional model
CN107192956A (en) * 2017-05-19 2017-09-22 北京理工大学 A kind of battery short circuit leakage on-line monitoring method and device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106168799A (en) * 2016-06-30 2016-11-30 常伟 A kind of method carrying out batteries of electric automobile predictive maintenance based on big data machine learning
CN106526493A (en) * 2016-11-01 2017-03-22 北京理工大学 Power battery external short circuit fault diagnosing and temperature rise prediction method and system based on BP neural networks
CN106980091A (en) * 2017-03-29 2017-07-25 北京理工大学 A kind of electrokinetic cell system health status method of estimation based on fractional model
CN107192956A (en) * 2017-05-19 2017-09-22 北京理工大学 A kind of battery short circuit leakage on-line monitoring method and device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109657720A (en) * 2018-12-20 2019-04-19 浙江大学 A kind of inline diagnosis method of power transformer shorted-turn fault
CN109657720B (en) * 2018-12-20 2021-05-11 浙江大学 On-line diagnosis method for turn-to-turn short circuit fault of power transformer
WO2020155233A1 (en) * 2019-01-28 2020-08-06 东北大学 Method for diagnosing external short circuit fault of lithium-ion battery pack on basis of two-stage model prediction
CN111537913A (en) * 2020-05-14 2020-08-14 广东汉力威技术有限公司 Method for diagnosing short circuit by using pre-discharge loop
CN116429339A (en) * 2023-06-07 2023-07-14 海斯坦普汽车组件(北京)有限公司 Leakage detection method and system for new energy battery box
CN116429339B (en) * 2023-06-07 2023-09-01 海斯坦普汽车组件(北京)有限公司 Leakage detection method and system for new energy battery box

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