CN113093038B - Power battery internal resistance composition analysis method based on pulse charge and discharge test - Google Patents
Power battery internal resistance composition analysis method based on pulse charge and discharge test Download PDFInfo
- Publication number
- CN113093038B CN113093038B CN202110236057.1A CN202110236057A CN113093038B CN 113093038 B CN113093038 B CN 113093038B CN 202110236057 A CN202110236057 A CN 202110236057A CN 113093038 B CN113093038 B CN 113093038B
- Authority
- CN
- China
- Prior art keywords
- terminal voltage
- value
- internal resistance
- power battery
- pulse
- 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
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Secondary Cells (AREA)
- Tests Of Electric Status Of Batteries (AREA)
Abstract
The invention provides a power battery internal resistance composition analysis method based on pulse charge and discharge tests. The method comprises the steps of adjusting to an SOC value to be tested, testing an alternating current internal resistance value, discharging with constant current pulses and obtaining a terminal voltage time sequence in the pulse discharging process, standing, charging with constant current pulses and obtaining a terminal voltage time sequence in the pulse charging process, analyzing the terminal voltage time sequence, and obtaining an electrochemical polarization internal resistance value and a concentration polarization internal resistance value of the power battery in the pulse discharging and charging processes respectively. The method uses simple and convenient steps to obtain the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which form the internal resistance of the power battery, and has scientific and reasonable method, good stability and no dependence on expensive and complex instruments.
Description
Technical Field
The invention relates to the field of lithium ion power batteries, in particular to a power battery internal resistance composition analysis method based on pulse charge and discharge tests.
Background
Lithium ion power batteries have been widely used because of their advantages of high energy density, good environmental suitability, high power density, and the like. Indexes such as rate performance, charge-discharge capacity, heat generation power and the like of the lithium ion power battery are influenced by internal resistance to a great extent. If the internal resistance of the lithium ion battery is larger, the rate capability and the charge-discharge capacity are reduced, the heat generation power is increased, and the heat management difficulty is increased. The total internal resistance of the lithium ion power battery mainly comprises three components of ohmic internal resistance, electrochemical polarization internal resistance and concentration polarization internal resistance. Wherein ohmic internal resistance is induced by ohmic polarization, the occurrence of which is instantaneous; the electrochemical internal resistance is caused by electrochemical polarization, and the main reason is that the electrochemical reaction speed on the positive electrode and the negative electrode of the battery is less than the movement speed of electrons, and the generation process is very short; the concentration polarization internal resistance is related to concentration polarization, and is polarization caused by the fact that the diffusion speed of lithium ions participating in the reaction is lower than the electrochemical reaction speed, the polarization speed is much lower than that of ohmic polarization and electrochemical polarization, and the concentration polarization is generally considered to be completed within seconds. The total internal resistance and the composition of the lithium ion power battery under different SOC (state of charge) are obtained, and the method is very important for the design, the process quality analysis, the performance evaluation, the service life prediction and the like of the lithium ion power battery. Generally, people obtain the alternating current internal resistance of the lithium ion power battery through an alternating current resistance tester, and approximately think that the alternating current internal resistance value is equal to the ohmic internal resistance; the total internal resistance of the lithium ion power battery including the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance is obtained through a pulse charge and discharge test, wherein the most typical test scheme is an HPPC (Hybrid pulse power characteristic) test.
In the prior known technical scheme, in order to accurately obtain the total internal resistance composition of the lithium ion power battery, an electrochemical workstation is required to be used for testing alternating current impedance and the like, which not only depends on expensive and precise professional instruments with complex operation, but also can only test laboratory samples rather than actual complete power battery products. The pulse charge and discharge test for the battery product only gives the total internal resistance of the battery. Therefore, a method for internal resistance test and analysis of the structure thereof, which is convenient to operate, scientific and reasonable and aims at the practical product of the lithium ion power battery, is urgently needed to be developed.
Disclosure of Invention
In order to solve the technical problems, the invention provides the power battery internal resistance composition analysis method based on the pulse charge-discharge test, which is convenient to operate, scientific and reasonable, and the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which are formed by the internal resistance of the power battery are obtained by using simple and convenient steps.
In order to achieve the purpose, the invention adopts the following technical scheme:
a power battery internal resistance composition analysis method based on pulse charge and discharge tests comprises the following operation steps:
(1) charging and discharging the power battery, adjusting the power battery to the SOC value required to be tested, standing for 1 hour +/-1 minute, measuring and recording the open-circuit voltage value U oc ；
(2) And testing and recording the alternating current internal resistance value R of the power battery by using an alternating current resistance tester 0 ；
(3) To power battery with I 1 The constant current pulse discharge time is 10 +/-0.5 seconds, the change condition of the terminal voltage of the power battery along with the time in the discharge process is recorded at fixed time intervals of delta t, and the terminal voltage time sequence { U ] in the pulse discharge process is obtained di In which I 1 Is a corresponding current value between 1C and 10C multiplying power, delta t is not more than 0.001 second, U di Representing the ith terminal voltage value in the power battery terminal voltage time sequence in the pulse discharging process;
(4) laying the power battery for 40 +/-1 seconds, measuring and recording an open-circuit voltage value U at the laying end moment od ；
(5) To power battery with I 2 The constant current pulse charging is carried out for 10 seconds, the change condition of the terminal voltage of the power battery in the charging process along with the time is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse charging process is obtained ci In which I 2 Is a corresponding current value between 1C and 5C multiplying power, delta t is not more than 0.001 second, U ci Representing the ith terminal voltage value in the terminal voltage time sequence in the pulse charging process;
(6) and combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse discharge process obtained in the step (3) di Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de Sum concentration polarization internal resistance value R dm ；
(7)、The ac internal resistance value R obtained in connection with step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse charging process obtained in the step (5) ci Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce Sum concentration polarization internal resistance value R cm 。
Preferably, the internal resistance composition analysis method of the power battery based on the pulse charge-discharge test comprises the following specific operation steps of (6):
(6.1) terminal voltage time sequence based on pulse discharge process { U di Subtracting each terminal voltage value from the next adjacent terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse discharging process di In which Δ U di Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse discharging process:
ΔU di ＝U di -U d(i+1) (1)
(6.2) terminal voltage difference time sequence based on pulse discharge process [ delta U ] di Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence d1 Are compared with each other until the first satisfaction of delta U is obtained dk <fΔU d1 The kth terminal voltage difference value DeltaU of this condition dk And recording the value of k, wherein f is a fixed value between 0.1 and 0.5;
(6.3) calculating electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de ：
R de ＝(U oc -U dk )/I 1 -R 0 (2)
In the formula of U oc Representing the open circuit voltage value obtained in the step (1); u shape dk Representing the kth terminal voltage value in the terminal voltage time sequence of the power battery in the pulse discharging process, wherein the k value is obtained in the step (6.2); i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2);
(6.4) calculating concentration polarization internal resistance R of the power battery in the pulse discharge process dm ：
R dm ＝(U oc -U dn )/I 1 -R 0 -R de (3)
In the formula of U oc Representing the open circuit voltage value obtained in the step (1); u shape dn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse discharging process; i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2); r is de And (4) obtaining the electrochemical polarization internal resistance value of the power battery in the pulse discharge process in the step (6.3).
Preferably, the invention relates to a power battery internal resistance composition analysis method based on pulse charge-discharge test, wherein the step (7) specifically comprises the following steps:
(7.1) terminal voltage time series { U) based on pulse charging process ci Starting from the 2 nd terminal voltage value, subtracting the previous terminal voltage value adjacent to each terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse charging process ci In which Δ U ci Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse charging process:
ΔU ci ＝U c(i+1) -U ci (4)
(7.2) terminal voltage difference value time series [ Delta U ] based on pulse charging process ci Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence c1 Are compared with each other until the first satisfaction of delta U is obtained cs <pΔU c1 The s terminal voltage difference value DeltaU of this condition cs And recording the value of s, wherein p is a fixed value between 0.1 and 0.5;
(7.3) calculating the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce ：
R ce ＝(U cs -U od )/I 2 -R 0 (5)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); u shape cs Representing the s terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process, wherein the s value is obtained in the step (7.2); i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2);
(7.4) calculating concentration polarization internal resistance value R of the power battery in the pulse charging process cm ：
R cm ＝(U cn -U od )/I 2 -R 0 -R ce (6)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); in the formula of U cn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process; i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2); r is ce And (4) the electrochemical polarization internal resistance value of the power battery for the pulse charging process obtained in the step (7.3).
Compared with the prior art, the invention has the following obvious prominent substantive characteristics and obvious advantages:
1. the invention uses the actual lithium ion power battery product as a test and analysis object, the test itself only needs to carry out the conventional alternating current resistance and pulse charge and discharge test, does not depend on expensive and complicated instruments such as an electrochemical workstation and the like, is simple and convenient to operate, and can directly test the power battery product itself;
2. according to the difference of the occurrence rates of the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which form the total internal resistance of the lithium ion power battery, the phase of rapid voltage drop or voltage rise at the end in a short time in the pulse discharge or charge process is regarded as the action of the ohmic internal resistance and the electrochemical polarization internal resistance through the analysis of the change rate of the end voltage, the change of the end voltage at the time of pulse discharge reduction is regarded as the action of the total internal resistance of the battery, and the measured alternating current resistance value is regarded as the ohmic internal resistance value, so that the accurate values of the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance can be respectively obtained through simple operation, and the scheme is scientific and reasonable and has good stability;
3. the method obtains the voltage difference value time sequence based on the pulse charge-discharge terminal voltage time sequence, compares the difference values in the sequence with the 1 st difference value in sequence, finds the inflection point of the difference value change from fast to slow as the starting point of the action of the concentration polarization internal resistance, effectively distinguishes the sum of the ohmic internal resistance and the electrochemical polarization internal resistance and the concentration polarization internal resistance by the data analysis means, and has small calculation amount, simplicity and effectiveness.
Drawings
Fig. 1 is a flow chart of a power battery internal resistance composition analysis method based on pulse charge and discharge testing in a preferred embodiment of the invention.
Detailed Description
The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings:
the first embodiment is as follows:
referring to fig. 1, a method for analyzing internal resistance composition of a power battery based on pulse charge and discharge test includes the following steps:
(1) charging and discharging the power battery, adjusting the power battery to the SOC value required to be tested, standing for 1 hour +/-1 minute, measuring and recording the open-circuit voltage value U oc ；
(2) And testing and recording the alternating current internal resistance value R of the power battery by using an alternating current resistance tester 0 ；
(3) To power battery with I 1 The constant current pulse discharge is carried out for 10 seconds +/-0.5 seconds, the change condition of the terminal voltage of the power battery along with the time in the discharge process is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse discharge process is obtained di In which I 1 Is a corresponding current value between 1C and 10C multiplying power, delta t is not more than 0.001 second, U di Representing the ith terminal voltage value in the power battery terminal voltage time sequence in the pulse discharging process;
(4) laying the power battery for 40 +/-1 seconds, measuring and recording an open-circuit voltage value U at the laying end moment od ；
(5) To power battery with I 2 The constant current pulse charging is carried out for 10 seconds +/-0.5 seconds, the change condition of the terminal voltage of the power battery in the charging process along with the time is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse charging process is obtained ci In which I 2 Is 1C to 5C timesCurrent values corresponding to the ratios, Δ t not more than 0.001 second, U ci Representing the ith terminal voltage value in the terminal voltage time sequence in the pulse charging process;
(6) and combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse discharge process obtained in the step (3) di Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de Sum concentration polarization internal resistance value R dm ；
(7) And combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse charging process obtained in the step (5) ci Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce Sum concentration polarization internal resistance value R cm 。
The embodiment uses simple and convenient steps to obtain the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which form the internal resistance of the power battery, and the method is scientific and reasonable, has good stability and does not depend on expensive and complex instruments
Example two:
referring to fig. 1, a method for analyzing internal resistance composition of a power battery based on pulse charge and discharge test includes the following steps:
(1) charging and discharging the power battery, adjusting the power battery to the SOC value required to be tested, standing for 1 hour, measuring and recording the open-circuit voltage value U oc ；
(2) And testing and recording the alternating current internal resistance value R of the power battery by using an alternating current resistance tester 0 ；
(3) To power battery with I 1 The constant current pulse discharge is carried out for 10 seconds, the change condition of the terminal voltage of the power battery along with the time in the discharge process is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse discharge process is obtained di In which I 1 Is a corresponding current value between 1C and 10C multiplying power, delta t is not more than 0.001 second, U di Representing the ith terminal voltage value in the power battery terminal voltage time sequence in the pulse discharging process;
(4) laying the power battery aside for 40 seconds, measuring and recording the open circuit at the laying-aside end momentVoltage value U od ；
(5) To power battery with I 2 The constant current pulse charging is carried out for 10 seconds, the change condition of the terminal voltage of the power battery in the charging process along with the time is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse charging process is obtained ci In which I 2 Is a corresponding current value between 1C and 5C multiplying power, delta t is not more than 0.001 second, U ci Representing the ith terminal voltage value in the terminal voltage time sequence in the pulse charging process;
(6) and combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse discharge process obtained in the step (3) di Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de Sum concentration polarization internal resistance value R dm ；
In this embodiment, step (6) is specifically divided into the following sub-steps:
(6.1) terminal voltage time sequence based on pulse discharge process { U di Subtracting each terminal voltage value from the next adjacent terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse discharging process di In which Δ U di Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse discharging process:
ΔU di ＝U di -U d(i+1) (1)
(6.2) terminal voltage difference time sequence based on pulse discharge process [ delta U ] di Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence d1 Are compared with each other until the first satisfaction of delta U is obtained dk <fΔU d1 The kth terminal voltage difference value DeltaU of this condition dk And recording the value of k, wherein f is a fixed value between 0.1 and 0.5;
(6.3) calculating the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de ：
R de ＝(U oc -U dk )/I 1 -R 0 (2)
In the formula of U dk RepresentsA kth terminal voltage value in a terminal voltage time sequence of the power battery in the pulse discharging process is obtained in the step (6.2); i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2);
(6.4) calculating concentration polarization internal resistance R of the power battery in the pulse discharge process dm ：
R dm ＝(U oc -U dn )/I 1 -R 0 -R de (3)
In the formula of U dn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse discharging process; i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2); r de And (4) obtaining the electrochemical polarization internal resistance value of the power battery in the pulse discharge process in the step (6.3).
(7) And combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse charging process obtained in the step (5) ci Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce Sum concentration polarization internal resistance value R cm 。
Referring to fig. 1, step (7) is specifically divided into the following sub-steps:
(7.1) terminal voltage time series { U) based on pulse charging process ci Starting from the 2 nd terminal voltage value, subtracting the previous terminal voltage value adjacent to each terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse charging process ci In which Δ U ci Representing the ith terminal voltage difference value in the terminal voltage difference value time sequence of the power battery in the pulse charging process:
ΔU ci ＝U c(i+1) -U ci (4)
(7.2) terminal voltage difference value time series [ Delta U ] based on pulse charging process ci Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence c1 Are compared with each other until the first satisfaction of delta U is obtained cs <pΔU c1 The s terminal voltage difference value DeltaU of this condition cs And recording the value of s, wherein p is a fixed value between 0.1 and 0.5;
(7.3) calculating the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce ：
R ce ＝(U cs -U od )/I 2 -R 0 (5)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); in the formula of U cs Representing the s terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process, wherein the s value is obtained in the step (7.2); i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2);
(7.4) calculating concentration polarization internal resistance value R of the power battery in the pulse charging process cm ：
R cm ＝(U cn -U od )/I 2 -R 0 -R ce (6)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); in the formula of U cn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process; i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2); r ce And (4) the electrochemical polarization internal resistance value of the power battery obtained in the step (7.3) in the pulse charging process.
The embodiments are further described below with reference to the drawings.
The nominal capacity of a certain square aluminum shell lithium ion power battery is 13Ah, the nominal voltage is 3.8V, the discharge cut-off voltage is 3.2V, the internal resistance composition of the power battery in 90% of SOC state is tested and analyzed, the test process is completed at room temperature, and the flow chart is shown in figure 1.
First, the cell was discharged to 3.2V at a constant current at 1C rate (i.e., current of 13A), left for 0.5 hours, and then charged to 90% SOC at 1C rate. After standing for 1 hour, measuring and recording the open-circuit voltage value U oc And (4.250) testing and recording the alternating current internal resistance value R of the power battery by using an alternating current resistance tester 0 ＝0.0012Ω。
Then, the power battery is charged with I 1 Pulse discharging for 10 seconds at constant current (corresponding to 6C multiplying power) of 78A, recording the change of terminal voltage of power battery in the discharging process along with time at fixed time intervals of 0.0005 seconds, and obtaining terminal voltage time sequence { U ] in the pulse discharging process di Laying aside for 40 seconds, measuring and recording an open-circuit voltage value U at the laying-aside end moment od ＝3.876V。
Then, the power battery is charged with I 2 Pulse charging at constant current (equivalent to 3C multiplying power) of 39A for 10 seconds, recording the variation of the terminal voltage of the power battery in the charging process along with the time at fixed time intervals of 0.0005 second, and obtaining the terminal voltage time sequence { U ] of the pulse charging process ci }。
The analysis of the test data of the pulsed discharge process now begins.
First, a terminal voltage time series { U ] based on a pulse discharge process di Subtracting each terminal voltage value from the next adjacent terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse discharging process di In which Δ U di Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse discharging process:
ΔU di ＝U di -U d(i+1) (1)
wherein, the 1 st terminal voltage difference value delta U is obtained by calculation d1 ＝U d1 -U d2 ＝4.052-4.002＝0.040V。
Secondly, taking f as 0.3, and based on a terminal voltage difference time sequence { delta U) in the pulse discharge process di Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence d1 Comparing with each other, finding the 6 th terminal voltage delta U d6 0.0151V, initially satisfies Δ U dk <fΔU d1 This condition corresponds to a k value of 6.
Thus, the terminal voltage time series { U ] is discharged from the pulse di Find U d6 Calculating electrochemical polarization internal resistance value R of the power battery in the pulse discharge process as 3.826V de ＝(U oc -U dk )/I 1 -R 0 ＝(4.250-3.826)/78-0.0012＝0.0042Ω。
Power battery terminal voltage time sequence { U ] in pulse discharging process di The last terminal voltage value U in dn 3.72V, so the concentration polarization internal resistance R of the power battery in the pulse discharge process is calculated dm ＝(U oc -U dn )/I 1 -R 0 -R de ＝(4.250-3.72)/78-0.0012-0.0042＝0.0014Ω。
Therefore, the power battery I to be tested 1 The ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance of the constant current pulse discharge process were 0.0012 Ω, 0.0042 Ω, and 0.0014 Ω, respectively, of 78A.
Next, the test data of the pulse charging process is analyzed.
First, based on the terminal voltage time series { U ] of the pulse charging process ci Starting from the 2 nd terminal voltage value, subtracting the previous terminal voltage value adjacent to each terminal voltage value to obtain a time sequence of terminal voltage difference values in the pulse charging process { delta U } ci In which Δ U ci Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse charging process:
ΔU ci ＝U c(i+1) -U ci (4)
wherein, the 1 st terminal voltage difference value delta U is obtained by calculation c1 ＝U c2 -U c1 ＝3.995-3.986＝0.009V。
Secondly, taking p as 0.3, and based on the voltage difference time sequence { delta U during pulse charging ci Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence c1 Comparing with each other, finding the 10 th terminal voltage delta U c10 When 0.0021V, Δ U starts to be satisfied cs <pΔU c1 This condition corresponds to an s value of 10.
Thus, the terminal voltage time series from the pulse charging process { U } ci Find U c10 Calculating the electrochemical polarization internal resistance value R of the power battery in the pulse charging process as 4.068V ce ＝(U cs -U od )/I 2 -R 0 ＝(4.068-3.876)/39-0.0012＝0.0037Ω。
Power battery terminal voltage time sequence { U ] in pulse charging process ci The last terminal voltage value U in cn 4.118V, the concentration polarization internal resistance R of the power battery in the pulse charging process is calculated cm ＝R cm ＝(U cn -U od )/I 2 -R 0 -R ce ＝(4.118-3.876)/39-0.0012-0.0037＝0.0013Ω。
Therefore, the tested power battery I 2 The ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance of the constant current pulse charging process, which is 39A, were 0.0012 Ω, 0.0037 Ω, and 0.0013 Ω, respectively.
The method for analyzing the internal resistance composition of the power battery based on the pulse discharge test provided by the embodiment performs conventional alternating current resistance and pulse discharge test on an actual lithium ion power battery product, does not depend on expensive and complex instruments such as an electrochemical workstation, and is simple and convenient to operate and direct in measurement means; according to the difference of the occurrence rates of the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which form the total internal resistance of the lithium ion power battery, analyzing the change rate of the end voltage, regarding the stage of rapid voltage drop (or rise) at the end in a short time in the pulse discharging (or charging) process as the action of the ohmic internal resistance and the electrochemical polarization internal resistance, regarding the change of the end voltage at the end of the pulse discharging as the action of the total internal resistance of the battery, and regarding the measured alternating current resistance value as the ohmic internal resistance value, so that the accurate values of the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance can be respectively obtained through simple operation, and the scheme is scientific and reasonable and has good stability; in the data analysis process, aiming at the terminal voltage difference value time sequence, the difference values in the sequence and the 1 st difference value are compared with each other in sequence, and the inflection point of the difference value change from fast to slow is found out to be used as the starting point of the action of the concentration polarization internal resistance, so that the sum of the ohmic internal resistance and the electrochemical polarization internal resistance and the concentration polarization internal resistance are effectively distinguished, and the calculation amount is small, simple and effective.
In summary, the power battery internal resistance composition analysis method based on the pulse charge and discharge test is provided in the above embodiments. The method comprises the steps of adjusting to an SOC value to be tested, testing an alternating current internal resistance value, discharging with constant current pulses and obtaining a terminal voltage time sequence in the pulse discharging process, standing, charging with constant current pulses and obtaining a terminal voltage time sequence in the pulse charging process, analyzing the terminal voltage time sequence, and obtaining an electrochemical polarization internal resistance value and a concentration polarization internal resistance value of the power battery in the pulse discharging and charging processes respectively. The method of the embodiment obtains the ohmic internal resistance, the electrochemical polarization internal resistance and the concentration polarization internal resistance which form the internal resistance of the power battery by using simple and convenient steps, is scientific and reasonable, has good stability and does not depend on expensive and complex instruments.
The embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the embodiments, and various changes and modifications can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention shall be equivalent substitutions, as long as the purpose of the present invention is met, and the present invention shall fall within the protection scope of the present invention without departing from the technical principle and inventive concept of the present invention.
Claims (2)
1. A power battery internal resistance composition analysis method based on pulse charge and discharge tests is characterized by comprising the following operation steps:
(1) charging and discharging the power battery, adjusting the power battery to the SOC value required to be tested, standing for 1 hour +/-1 minute, measuring and recording the open-circuit voltage value U oc ；
(2) Testing by using an alternating current resistance tester, and recording to obtain the alternating current internal resistance value R of the power battery 0 ；
(3) To power battery with I 1 The constant current pulse discharge is carried out for 10 seconds +/-0.5 seconds, the change condition of the terminal voltage of the power battery along with the time in the discharge process is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse discharge process is obtained di In which I 1 Is a current value corresponding to 1C to 10C multiplying power, delta t is not more than 0.001 second, U di Representing the terminal voltage of the power cell during pulse dischargeThe ith terminal voltage value in the sequence;
(4) laying the power battery for 40 +/-1 seconds, measuring and recording an open-circuit voltage value U at the laying end moment od ；
(5) To power battery with I 2 The constant current pulse charging is carried out for 10 seconds +/-0.5 seconds, the change condition of the terminal voltage of the power battery in the charging process along with the time is recorded at fixed time intervals of delta t, and a terminal voltage time sequence { U ] in the pulse charging process is obtained ci In which I 2 Is a corresponding current value between 1C and 5C multiplying power, delta t is not more than 0.001 second, U ci Representing the ith terminal voltage value in the terminal voltage time sequence in the pulse charging process;
(6) and combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse discharge process obtained in the step (3) di Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de Sum concentration polarization internal resistance value R dm ；
(7) And combining the AC internal resistance value R obtained in step S2 0 Analyzing the terminal voltage time sequence { U ] of the pulse charging process obtained in the step (5) ci Obtaining the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce Sum concentration polarization internal resistance value R cm ；
The specific operation step of the step (6) is as follows:
(6.1) terminal voltage time sequence based on pulse discharge process { U di Subtracting each terminal voltage value from the next adjacent terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse discharging process di In which Δ U di Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse discharging process:
ΔU di ＝U di -U d(i+1) (1)
(6.2) terminal voltage difference time sequence based on pulse discharge process [ delta U ] di Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence d1 Are compared with each other until the first satisfaction of delta U is obtained dk <fΔU d1 The k-th of this conditionTerminal voltage difference value delta U dk And recording the value of k, wherein f is a fixed value between 0.1 and 0.5;
(6.3) calculating the electrochemical polarization internal resistance value R of the power battery in the pulse discharge process de ：
R de ＝(U oc -U dk )/I 1 -R 0 (2)
In the formula of U oc Representing the open circuit voltage value obtained in the step (1); u shape dk Representing the kth terminal voltage value in the terminal voltage time sequence of the power battery in the pulse discharging process, wherein the k value is obtained in the step (6.2); i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2);
(6.4) calculating concentration polarization internal resistance R of the power battery in the pulse discharge process dm ：
R dm ＝(U oc -U dn )/I 1 -R 0 -R de (3)
In the formula of U oc Representing the open circuit voltage value obtained in the step (1); u shape dn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse discharging process; i is 1 The pulse discharge current value in the step (3); r 0 The alternating current internal resistance value obtained in the step (2); r de And (4) obtaining the electrochemical polarization internal resistance value of the power battery in the pulse discharge process in the step (6.3).
2. The method for analyzing the internal resistance composition of the power battery based on the pulse charge-discharge test is characterized in that the specific operation step of the step (7) is as follows:
(7.1) terminal voltage time series { U) based on pulse charging process ci Starting from the 2 nd terminal voltage value, subtracting the previous terminal voltage value adjacent to each terminal voltage value to obtain a terminal voltage value time sequence { delta U ] of the pulse charging process ci In which Δ U ci Representing the ith terminal voltage difference value in the power battery terminal voltage difference value time sequence in the pulse charging process:
ΔU ci ＝U c(i+1) -U ci (4)
(7.2) terminal voltage difference value time series [ Delta U ] based on pulse charging process ci Respectively comparing each terminal voltage difference value with the 1 st terminal voltage difference value delta U in sequence c1 Are compared with each other until the first satisfaction of delta U is obtained cs <pΔU c1 The s terminal voltage difference value DeltaU of this condition cs And recording the value of s, wherein p is a fixed value between 0.1 and 0.5;
(7.3) calculating the electrochemical polarization internal resistance value R of the power battery in the pulse charging process ce ：
R ce ＝(U cs -U od )/I 2 -R 0 (5)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); u shape cs Representing the s terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process, wherein the s value is obtained in the step (7.2); i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2);
(7.4) calculating concentration polarization internal resistance value R of the power battery in the pulse charging process cm ：
R cm ＝(U cn -U od )/I 2 -R 0 -R ce (6)
In the formula of U od Representing the open circuit voltage value obtained in the step (4); u shape cn Representing the last terminal voltage value in the terminal voltage time sequence of the power battery in the pulse charging process; i is 2 The pulse charging current value in the step (5); r 0 The alternating current internal resistance value obtained in the step (2); r ce And (4) the electrochemical polarization internal resistance value of the power battery obtained in the step (7.3) in the pulse charging process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110236057.1A CN113093038B (en) | 2021-03-03 | 2021-03-03 | Power battery internal resistance composition analysis method based on pulse charge and discharge test |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110236057.1A CN113093038B (en) | 2021-03-03 | 2021-03-03 | Power battery internal resistance composition analysis method based on pulse charge and discharge test |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113093038A CN113093038A (en) | 2021-07-09 |
| CN113093038B true CN113093038B (en) | 2022-08-05 |
Family
ID=76666311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110236057.1A Active CN113093038B (en) | 2021-03-03 | 2021-03-03 | Power battery internal resistance composition analysis method based on pulse charge and discharge test |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113093038B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109143106A (en) * | 2018-08-09 | 2019-01-04 | 南京卡耐新能源技术发展有限公司 | A method of battery consistency is quickly detected by ac impedance measurement |
| CN111007400A (en) * | 2019-11-22 | 2020-04-14 | 西安工程大学 | Lithium battery SOC estimation method based on self-adaptive double-extended Kalman filtering method |
| CN111208352A (en) * | 2020-01-19 | 2020-05-29 | 广东科学技术职业学院 | Storage battery internal resistance measuring method and system |
| CN111751731A (en) * | 2020-07-19 | 2020-10-09 | 东北石油大学 | Method and device for determining battery activity, electronic equipment and storage medium |
| CN212275916U (en) * | 2020-04-14 | 2021-01-01 | 浙江华云信息科技有限公司 | Battery internal resistance component measuring device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105576306A (en) * | 2014-10-17 | 2016-05-11 | 东莞新能源科技有限公司 | Fast battery charging method |
| CN106125000A (en) * | 2016-08-18 | 2016-11-16 | 中国电力科学研究院 | A kind of method of testing of lithium battery ohmic internal resistance based on dipulse electric current |
| CN109752663A (en) * | 2017-11-01 | 2019-05-14 | 微宏动力系统（湖州）有限公司 | A kind of measurement method of the internal resistance of cell |
| JP7067566B2 (en) * | 2017-12-13 | 2022-05-16 | 住友電気工業株式会社 | Battery monitoring device, computer program and battery monitoring method |
| JP2020106317A (en) * | 2018-12-26 | 2020-07-09 | Fdk株式会社 | Method for identifying internal resistance of lithium primary battery, depth of discharge estimation device, and depth of discharge estimation method |
| CN109946613A (en) * | 2019-04-08 | 2019-06-28 | 上海理工大学 | The internal resistance On-line Estimation and life detecting method of Vehicular dynamic battery |
| CN111426971A (en) * | 2020-04-14 | 2020-07-17 | 浙江华云信息科技有限公司 | Method and device for measuring battery internal resistance component |
-
2021
- 2021-03-03 CN CN202110236057.1A patent/CN113093038B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109143106A (en) * | 2018-08-09 | 2019-01-04 | 南京卡耐新能源技术发展有限公司 | A method of battery consistency is quickly detected by ac impedance measurement |
| CN111007400A (en) * | 2019-11-22 | 2020-04-14 | 西安工程大学 | Lithium battery SOC estimation method based on self-adaptive double-extended Kalman filtering method |
| CN111208352A (en) * | 2020-01-19 | 2020-05-29 | 广东科学技术职业学院 | Storage battery internal resistance measuring method and system |
| CN212275916U (en) * | 2020-04-14 | 2021-01-01 | 浙江华云信息科技有限公司 | Battery internal resistance component measuring device |
| CN111751731A (en) * | 2020-07-19 | 2020-10-09 | 东北石油大学 | Method and device for determining battery activity, electronic equipment and storage medium |
Non-Patent Citations (2)
| Title |
|---|
| State of charge estimation based on a new dual-polarization resistance model for electric vehicles;Xiaowei Zhao, Yishan Cai, Lin Yang;《ENERGY》;20170618;第135卷;40-52 * |
| 混动车用氢镍动力电池欧姆内阻估算方法研究;倪红军，陈青青，陈祥，朱建新，储爱华;《电源技术》;20180330;第3卷(第42期);399-403 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113093038A (en) | 2021-07-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103344917B (en) | A kind of lithium battery cycle life method for rapidly testing | |
| CN110988086B (en) | Method for detecting structural stability of electrode material in battery cycle process | |
| CN109663756B (en) | Battery core screening method and medium based on self-discharge rate | |
| CN113777501B (en) | SOH estimation method of battery module | |
| CN108732499B (en) | Method and system for detecting cycle life of lithium ion battery | |
| CN111458642A (en) | Nondestructive testing method for lithium separation of lithium ion storage battery | |
| CN112098866B (en) | Nondestructive analysis method for judging whether lithium separation occurs in battery circulation process | |
| CN112526352B (en) | SOH estimation method for retired lithium ion battery | |
| CN111366863B (en) | Lithium ion battery service life acceleration pre-judging method based on low-temperature circulation | |
| Banaei et al. | Real time condition monitoring in Li-Ion batteries via battery impulse response | |
| CN111216595B (en) | SOC calibration method of severe hybrid electric vehicle based on lithium battery equivalent circuit model | |
| CN111896880A (en) | Method for detecting service life of lithium ion battery for electric vehicle | |
| CN113296010B (en) | Battery health state online evaluation method based on differential voltage analysis | |
| CN112924869B (en) | Method and device for determining health state of battery pack | |
| CN112130080B (en) | Accurate measurement method for SOC-OCV curve of power lithium ion battery at low temperature | |
| CN113093038B (en) | Power battery internal resistance composition analysis method based on pulse charge and discharge test | |
| CN110031772B (en) | Real-time estimation method for equivalent internal resistance of lithium ion battery | |
| CN117471324A (en) | Method and device for evaluating consistency of single capacity in battery module | |
| CN112114260A (en) | Method for testing and evaluating overcharge stability of lithium ion battery monomer | |
| CN116718932A (en) | Method for testing critical lithium-ion battery lithium-ion current | |
| CN116413608A (en) | Lithium ion battery state of charge and state of health joint estimation method | |
| CN112649735A (en) | Method for rapidly obtaining total capacity of battery pack | |
| JP4606641B2 (en) | Method and apparatus for determining deterioration of lithium secondary battery | |
| JP2964745B2 (en) | Inspection methods for sealed lead-acid batteries | |
| Joshi et al. | Analyzing Internal Resistance in Lithium Nickel Cobalt Oxide (LiNiCoO) Vehicle Batteries for Enhanced SOC and SOH Prediction |
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 |