CN107045103B - Device and method for testing service life of power battery of electric automobile - Google Patents

Abstract

The invention discloses an electric vehicle power battery life testing device and method. It uses the vibration table to apply the vibration of the tested electric vehicle power battery to simulate road driving, and uses the constant temperature and humidity chamber to simulate the temperature and humidity throughout the year, and then uses the charging and discharging equipment to charge and discharge the tested electric vehicle power battery. Simulate road running current and collect relevant data, record and derive the battery information, and determine the life of the tested electric vehicle power battery. The invention comprehensively considers comprehensive factors such as changes in temperature and humidity in four seasons, charging and discharging conditions, charging and discharging depth, and vibration conditions, and includes various operating states of electric vehicle power batteries. The aging extrapolation formula is fitted, and the corresponding life is deduced, so it is a more accurate life evaluation test model. It intercepts some stages in the life decline process, thus greatly shortening the test time.

Description

Electric vehicle power battery life testing device and method

technical field

The invention relates to the field of electric vehicle power battery testing, in particular to an electric vehicle power battery life testing device and method.

Background technique

As the core component of electric vehicles, the life test and evaluation of power battery is very necessary and important for R&D and application. If the service life of the power battery is known and the failure time is predicted, the R&D department can design or modify the product accordingly, and the manufacturer can grasp the product quality and service cycle, thereby providing a basis for cost calculation and fault repair. However, if the road test is used for the life test, although it is closer to the actual working conditions, the time period is very long and the cost is high, and it is not suitable for the needs of current engineering development. Therefore, the life of electric vehicle power battery pack should be estimated in advance and then obtained by accelerated test.

From the current research on the accelerated life model of power batteries, there are mainly the following problems.

The first problem is that the acceleration model only considers one or a few stresses, but the influencing factors caused by the interaction between multiple stresses are not considered, so it is difficult to truly represent the actual complex working conditions of the electric vehicle power battery.

For example, consider only a linear fit model for charge and discharge current conditions:

y=kx+b

Among them, k and b are the constants to be measured in the test, x is the number of cycles, and y is the capacity to be measured. The working conditions in this model only consider the charging and discharging current.

As another example, consider the life model of temperature and electrical stress:

L=exp[A(E)+B(E)/T]

in

A(E)=A ₁ +A ₂ E

B(E)=B ₁ +B ₂ E

Among them, T is the absolute temperature, E is the electrical stress, A ₁ , A ₂ , B ₁ , and B ₂ are constants, all obtained from the experimental data, because when the electrical stress is below a certain level, the life of the power battery is similar to this The correlation of electrical stress is small, so this model cannot fully reflect the relationship between the life of the power battery and the various stresses.

The second problem is that the multi-stress acceleration model considering mutual influence is complicated to solve and has too many assumptions. The authenticity of the prediction needs to be further verified.

For example, consider a pH model for multiple stresses:

为只与各种应力相关而与时间无关的正函数，其中为行向量，

为列向量，

m为与时间独立的应力变量个数。从中可以看出，求解该模型变得相当复杂，且参数更多。where λ ₀ (t) is the time-dependent basic failure function,

is a positive function related only to various stresses and independent of time, where is a row vector,

is a column vector,

m is the number of time-independent stress variables. As can be seen, solving the model becomes quite complex and has more parameters.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an electric vehicle power battery life testing device and method, which can simply and quickly measure the life of an electric vehicle power battery under the condition of considering multiple factors at the same time.

The invention provides an electric vehicle power battery life test device, comprising:

A vibration table, the electric vehicle power battery to be tested is fixedly installed on the vibration table, and the vibration table can vibrate according to the set frequency, acceleration and displacement;

a constant temperature and humidity chamber, wherein the vibrating table and the electric vehicle power battery fixedly mounted thereon are placed together in the constant temperature and humidity chamber, and the constant temperature and humidity chamber can provide a constant temperature and humidity environment according to the set temperature and humidity;

A charging and discharging device, the charging and discharging device is located outside the constant temperature and humidity room and is electrically connected to the electric vehicle power battery to be tested, so as to charge and discharge the electric vehicle power battery and record the electric vehicle power battery voltage, current and temperature; and,

A control computer, which is located outside the constant temperature and humidity room and is electrically connected to the vibrating table and the charging and discharging equipment, so as to control the vibrating table to vibrate according to the set frequency, acceleration and displacement, and control the charging and discharging equipment. The discharge device charges and discharges the electric vehicle power battery and collects battery information, and calculates the estimated life mileage of the tested electric vehicle power battery (2) according to the collected battery information.

Further, the charging and discharging device is connected to the electric vehicle power battery through a main cable, so as to charge and discharge the electric vehicle power battery; and,

The charging and discharging device is connected to the electric vehicle power battery through a voltage collection line, a current collection line and a temperature collection line, so as to collect voltage, current and temperature information of the electric vehicle power battery.

Further, the battery information includes voltage, current and temperature information of the electric vehicle power battery.

Further, the control computer is connected to the charging and discharging device through a data cable, so as to obtain the battery information through the data cable, and use the battery information to determine the life of the tested electric vehicle power battery.

The present invention also provides a life test method for an electric vehicle power battery. The electric vehicle power battery life test method adopts the electric vehicle power battery life test device described in any one of the above, and the method includes:

respectively setting the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition;

Use the vibration table to simulate the vibration of the car while driving;

While the vibrating table vibrates, a first charge-discharge cycle operation is performed on the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence, and the first charge-discharge cycle is obtained. A first trend formula for the change of the discharge capacity of the tested electric vehicle power battery with time in a charge-discharge cycle operation, and a second trend formula for the change of the maximum cell voltage difference of the tested electric vehicle power battery with time;

Use the first trend formula and the second trend formula to iteratively calculate the subsequent charging and discharging cycles of the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence The discharge capacity of the tested electric vehicle power battery and the maximum cell voltage difference of the tested electric vehicle power battery;

When the iteratively calculated discharge capacity reaches the preset discharge capacity threshold, or when the iteratively calculated maximum cell voltage difference reaches the preset voltage difference threshold, stop the iterative calculation;

When the iterative calculation is stopped, the accumulated time of all the cycles that have been experienced is used as the estimated life of the tested electric vehicle power battery, and the vibration spectrum line of the vibration table within the estimated life of the tested electric vehicle power battery corresponds to The mileage of the vehicle is used as the estimated life mileage of the tested electric vehicle power battery.

Further, a first charge-discharge cycle operation is performed on the tested electric vehicle power battery under the first environment condition, the second environment condition, the third environment condition and the fourth environment condition in sequence, and the first charge-discharge cycle operation is obtained. The first trend formula of the tested electric vehicle power battery's discharge capacity with time, and the second trend formula of the tested electric vehicle power battery's maximum cell voltage difference with time, including:

Execute the first charge-discharge cycle LOOP1 process:

Under the first environmental condition, the following steps a to c are performed:

Step a, in the state that the vibration table does not vibrate, turn on the charging and discharging equipment, and charge the tested electric vehicle power battery to the maximum SOC with Ic current;

Step b, turning on the vibrating table, so that the vibrating table applies vibration to the electric vehicle power battery under test according to the power battery vibration spectrum line when the vehicle is running, and simultaneously uses the charging and discharging equipment to conduct the electric vehicle power battery. Discharge, when the power of the power battery is discharged, in the state that the vibration table does not vibrate, the tested electric vehicle power battery is charged to the maximum SOC with Ic current;

Step c, repeat the discharging and charging process of the above-mentioned step b, and collect the voltage and current of the electric vehicle power battery under test during the discharging and charging process of the above-mentioned step b, and calculate the voltage and current of the electric vehicle power battery under test every time the electric vehicle power battery is discharged. The discharge capacity value Q _11i and the maximum voltage difference ΔU _11i of the single cell in the tested electric vehicle power battery, and record the total time t, where i represents the number of discharges;

Under the first environmental condition, when the calculated discharge capacity Q _11i has a downward trend, under the second environmental condition, the processes of the above steps b and c are performed, wherein the above steps are performed under the second environmental condition The process of b and step c is the same as the duration of the process of performing the above-mentioned steps b and step c under the first environmental condition;

After the process of performing the above-mentioned steps b and c under the second environmental condition is completed, the above-mentioned process of the above-mentioned steps b and the step c is performed under the third environmental condition, wherein the above-mentioned steps b and the above-mentioned steps are performed under the third environmental condition. The process of step c is the same as the duration of the process of performing the above-mentioned steps b and step c under the first environmental condition;

After the process of performing the above step b and step c under the third environmental condition is completed, the process of the above step b and step c is continued to be performed under the fourth environmental condition, wherein the above step b is performed under the fourth environmental condition and the process of step c, the same duration as the process of performing the above-mentioned steps b and step c under the first environmental condition;

Approximate formulas Q _a1 =f _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 = f _a2 (t) and ΔU _a2 =φ _AA (t), Q _a3 =f ₁₃ (t) and ΔU _a3 =φ _a3 (t), Q _a4 =f ₁₄ (t) and ΔU _a4 =φ _a4 (t) , where Q _a1 is the time-varying value of the discharge capacity of the tested electric vehicle power battery under the first environmental condition, and ΔU _a1 is the maximum cell voltage difference of the tested electric vehicle power battery under the first environmental condition The value of the change with time t, Q _a2 is the value of the discharge capacity of the tested electric vehicle power battery with time t under the second environmental condition, ΔU _a2 is the tested electric vehicle power battery under the second environmental condition. The value of the maximum cell voltage difference with time t, Q _a3 is the value of the discharge capacity of the tested electric vehicle power battery with time t under the third environmental condition, ΔU _a3 is the tested value under the third environmental condition The value of the maximum cell voltage difference of the electric vehicle power battery changing with time t, Q _a4 is the value of the discharge capacity of the tested electric vehicle power battery changing with time t under the fourth environmental condition, ΔU _a4 is the fourth environmental condition The value of the maximum cell voltage difference of the tested electric vehicle power battery changing with time t, t is the discharge time;

End the first charge-discharge cycle LOOP1 process.

Further, using the first trend formula and the second trend formula to iteratively calculate the subsequent charging of the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence. The discharge capacity of the tested electric vehicle power battery for the discharge cycle and the maximum cell voltage difference of the tested electric vehicle power battery, including:

In the first charge-discharge cycle LOOP1, the last complete discharge capacity value Q _14n and the maximum cell voltage difference ΔU _14n in the fourth environmental condition stage are taken as the values of the first environmental condition stage of the second charge-discharge cycle LOOP2. The first discharge capacity value Q ₂₁₁ and the maximum voltage difference ΔU ₂₁₁ of the single cell in the electric vehicle power battery to be tested for the first time, according to the above-mentioned first environmental condition stage, second environmental condition stage, and third environmental condition Stage, Approximate Formulas for the Fourth Ambient Conditions Stage Q _a1 =f _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 =f _a2 (t) and ΔU _a2 =φ ₁₂ (t), Q _a3 =f ₁₃ (t) and ΔU _a3 =φ _a3 (t), Q _a4 =f ₁₄ (t) and ΔU _a4 =φ _a4 (t), the fourth environment in the second charge-discharge cycle LOOP2 is derived from Q ₂₁₁ and ΔU ₂₁₁ The last complete discharge capacity Q _24n and the maximum cell voltage difference ΔU _24n of the conditional stage;

The above calculation is repeated to sequentially obtain the last complete discharge capacity value and the maximum cell voltage difference value of the fourth environmental condition stage in each charge-discharge cycle after the second charge-discharge cycle LOOP2.

Further, the first environmental condition is: the constant temperature and humidity chamber is set to a first average temperature and a first average humidity;

The second environmental condition is: the constant temperature and humidity chamber is set to a second average temperature and a second average humidity;

The third environmental condition is: the constant temperature and humidity chamber is set to a third average temperature and a third average humidity;

The fourth environmental condition is: the constant temperature and humidity chamber is set to a fourth average temperature and a fourth average humidity.

Further, the first environmental conditions, the second environmental conditions, the third environmental conditions and the fourth environmental conditions correspond to the use environmental conditions of the electric vehicle power battery in winter, spring, summer and autumn, respectively.

It can be seen from the above solutions that the device and method for testing the life of an electric vehicle power battery of the present invention simultaneously considers various factors such as ambient temperature and humidity, charging and discharging current conditions, charging and discharging depth, and vibration during driving, and basically includes The complex working conditions of the actual operation of the power battery, and at the same time, according to the fact that the failure mechanism of the material remains unchanged within the limit range, the appropriate test time is intercepted, and the relationship between the discharge capacity and time of the power battery pack is fitted, so as to use this relationship Iteratively iterates the formula to obtain a high-precision predicted life. Compared with the original method, the present invention has high prediction accuracy because it considers various working condition factors affecting the power battery pack, and does not presuppose a complex model, but only solves the final model formula by means of experiments and segmental fitting. (a variety of main influencing conditions are considered, and it is based on the common assumption that the material failure mechanism remains unchanged within the limit range), the test time is short (a part of the test time is intercepted), and the implementation is simple (no need to build a complex life model ) and other advantages, it is very suitable for rapid evaluation of electric vehicle power battery life.

Description of drawings

The following drawings merely illustrate and explain the present invention schematically, and do not limit the scope of the present invention.

1 is a schematic diagram of an electric vehicle power battery life testing device according to an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for testing the life of an electric vehicle power battery according to an embodiment of the present invention.

Label description

11. Vibration table

12. Constant temperature and humidity room

13. Charging and discharging equipment

14. Control computer

2. Electric vehicle power battery

Detailed ways

In order to have a clearer understanding of the technical features, objects and effects of the invention, the specific embodiments of the invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same parts.

As used herein, "schematic" means "serving as an example, instance, or illustration" and any illustration, embodiment described herein as "schematic" should not be construed as a preferred or advantageous one Technical solutions.

In order to make the drawings concise, only the relevant parts of the present invention are schematically shown in each drawing, and do not represent the actual structure of the product. In addition, in order to make the drawings concise and easy to understand, in some drawings, only one of the components having the same structure or function is schematically shown, or only one of them is marked.

As used herein, "one" does not mean to limit the number of relevant parts of the invention to "only one", and "one" does not mean to exclude "more than one" number of relevant parts of the invention.

In this document, "upper", "lower", "front", "rear", "left", "right", etc. are only used to indicate the relative positional relationship between related parts, rather than limit the absolute positions of these related parts .

In this document, "first", "second", etc. are only used to distinguish each other, but do not indicate the degree of importance and order, and the premise of mutual existence.

In this paper, "equal", "same" and the like are not limitations in strict mathematical and/or geometric senses, and also include errors that can be understood by those skilled in the art and allowed by manufacturing or use. Unless otherwise indicated, numerical ranges herein include not only the entire range between its two endpoints, but also several subranges subsumed therein.

As shown in FIG. 1 , the electric vehicle power battery life testing device according to the embodiment of the present invention includes a vibration table 11 , a constant temperature and humidity chamber 12 , a charging and discharging device 13 and a control computer 14 . Wherein, the tested electric vehicle power battery 2 is fixedly installed on the vibration table 11, and the vibration table 11 can vibrate according to the set frequency, acceleration and displacement. The vibrating table 11 is placed in the constant temperature and humidity chamber 12 together with the electric vehicle power battery 2 fixedly mounted thereon, and the constant temperature and humidity chamber 12 can provide a constant temperature and humidity environment according to the set temperature and humidity. The charging and discharging device 13 is located outside the constant temperature and humidity chamber 12 , and the charging and discharging device 13 is electrically connected to the electric vehicle power battery 2 to be tested, so as to charge and discharge the electric vehicle power battery 2 And record the voltage, current and temperature of the electric vehicle power battery 2 . The control computer 14 is located outside the constant temperature and humidity chamber 13, and the control computer 14 is electrically connected to the vibration table 11 and the charging and discharging device 13 to control the vibration table 11 according to the set frequency, The acceleration and displacement vibrate, and the charging and discharging device 13 is controlled to charge and discharge the electric vehicle power battery 2 and collect battery information. The battery information includes voltage, current and temperature information of the electric vehicle power battery 2 .

In the embodiment of the present invention, the charging and discharging device 13 is connected to the electric vehicle power battery 2 through a main cable, so as to charge and discharge the electric vehicle power battery 2 . In addition, in order to collect the voltage, current and temperature information of the electric vehicle power battery 2, the charging and discharging device 13 is also connected to the electric vehicle power battery 2 through a voltage collection line, a current collection line and a temperature collection line to collect The voltage, current and temperature information of the electric vehicle power battery 2 . FIG. 1 is only for illustration, and does not specifically show the connection relationship of various cables, such as the voltage collection line, the current collection line, and the temperature collection line.

In the embodiment of the present invention, the control computer 14 is connected to the charging and discharging device 13 through a data line, so as to obtain the battery information (ie, the voltage, current and temperature information of the electric vehicle power battery 2 ) through the data line ), and use the battery information to determine the life of the tested electric vehicle power battery 2, that is, to calculate the estimated life mileage of the tested electric vehicle power battery 2 according to the collected battery information.

In the embodiment of the present invention, the lifespan of the electric vehicle power battery 2 is mainly obtained by using the charging and discharging device 13 to charge and discharge the electric vehicle power battery 2. The relationship between battery information and time, A correlation formula is fitted, and then the correlation formula is used to extrapolate to determine the life of the electric vehicle power battery 2 . The relevant calculation work is performed by the control computer 14 using the collected battery information and time.

The electric vehicle power battery life test method according to the embodiment of the present invention adopts the above-mentioned electric vehicle power battery life test device, as shown in FIG. 2 , the method includes:

respectively setting the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition;

Use the vibration table to simulate the vibration of the car while driving;

While the vibrating table vibrates, a first charge-discharge cycle operation is performed on the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence, and the first charge-discharge cycle is obtained. A first trend formula of the discharge capacity of the tested electric vehicle power battery over time in a charge-discharge cycle operation, and a second trend formula of the maximum cell voltage difference of the tested electric vehicle power battery over time, wherein , the discharge capacity refers to the amount of electricity released by discharge, in Ah (Ah);

Use the first trend formula and the second trend formula to iteratively calculate the subsequent charging and discharging cycles of the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence The discharge capacity of the tested electric vehicle power battery and the maximum cell voltage difference of the tested electric vehicle power battery;

When the iteratively calculated discharge capacity reaches the preset discharge capacity threshold, or when the iteratively calculated maximum cell voltage difference reaches the preset voltage difference threshold, stop the iterative calculation;

When the iterative calculation is stopped, the accumulated time of all the cycles that have been experienced is used as the estimated life of the tested electric vehicle power battery, and the vibration spectrum line of the vibration table within the estimated life of the tested electric vehicle power battery corresponds to The mileage of the vehicle is used as the estimated life mileage of the tested electric vehicle power battery.

Further, in the above method, a first charge-discharge cycle operation is performed on the tested electric vehicle power battery under the first environment condition, the second environment condition, the third environment condition and the fourth environment condition in sequence, and the first charge-discharge cycle is obtained. The first trend formula of the discharge capacity of the tested electric vehicle power battery with time in the discharge cycle operation, and the second trend formula of the tested electric vehicle power battery's maximum cell voltage difference with time, including:

Execute the first charge-discharge cycle LOOP1 process:

Under the first environmental condition, the following steps a to c are performed:

Step a, in the state that the vibration table does not vibrate, turn on the charging and discharging equipment, charge the tested electric vehicle power battery to the maximum SOC with Ic current, and let it stand for a period of time, and the standstill time can be based on It depends on the actual situation;

Step b, turning on the vibrating table, so that the vibrating table applies vibration to the electric vehicle power battery under test according to the power battery vibration spectrum line when the vehicle is running, and simultaneously uses the charging and discharging equipment to conduct the electric vehicle power battery. Simulate the discharge of the real operating current (or NEDC), when the power of the power battery is discharged (that is, when it is discharged to the cut-off voltage of the power battery), in the state that the vibration table does not vibrate, the Ic current is used to test the The electric vehicle power battery is charged to the maximum SOC and left for a period of time, which can be determined according to the actual situation;

Step c, repeat the discharging and charging process of the above-mentioned step b, and collect the voltage and current of the electric vehicle power battery under test during the discharging and charging process of the above-mentioned step b, and calculate the voltage and current of the electric vehicle power battery under test every time the electric vehicle power battery is discharged. The discharge capacity value Q _11i and the maximum voltage difference ΔU _11i of the single battery in the tested electric vehicle power battery, and record the total time t, where i represents the number of discharges, and the total time t includes charging, discharging and resting Time, that is, the total time t = charging time + resting time + discharging time;

Under the first environmental condition, when the calculated discharge capacity Q _11i has a downward trend, under the second environmental condition, the processes of the above steps b and c are performed, wherein the above steps are performed under the second environmental condition The process of b and step c is the same as the duration of the process of performing the above-mentioned steps b and step c under the first environmental condition;

After the process of performing the above-mentioned steps b and c under the second environmental condition is completed, the above-mentioned process of the above-mentioned steps b and the step c is performed under the third environmental condition, wherein the above-mentioned steps b and the above-mentioned steps are performed under the third environmental condition. The process of step c is the same as the duration of the process of performing the above-mentioned steps b and step c under the first environmental condition;

After the process of performing the above-mentioned steps b and c under the third environmental condition is completed, the above-mentioned process of the above-mentioned steps b and the step c is performed under the fourth environmental condition, wherein the above-mentioned steps b and the above-mentioned steps are performed under the fourth environmental condition. The process of step c is the same as the duration of the process of performing the above-mentioned steps b and step c under the first environmental condition;

Approximate formulas Q _a1 =f _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 = f _a2 (t) and ΔU _a2 =φ ₁₂ (t), Q _a3 =f ₁₃ (t) and ΔU _a3 =φ _a3 (t), Q _a4 =f ₁₄ (t) and ΔU _a4 =φ _a4 (t) , where Q _a1 is the time-varying value of the discharge capacity of the tested electric vehicle power battery under the first environmental condition, and ΔU _a1 is the maximum cell voltage difference of the tested electric vehicle power battery under the first environmental condition The value of the change with time t, Q _a2 is the value of the discharge capacity of the tested electric vehicle power battery with time t under the second environmental condition, ΔU _a2 is the tested electric vehicle power battery under the second environmental condition. The value of the maximum cell voltage difference with time t, Q _a3 is the value of the discharge capacity of the tested electric vehicle power battery with time t under the third environmental condition, ΔU _a3 is the tested value under the third environmental condition The value of the maximum cell voltage difference of the electric vehicle power battery changing with time t, Q _a4 is the value of the discharge capacity of the tested electric vehicle power battery changing with time t under the fourth environmental condition, ΔU _a4 is the fourth environmental condition The value of the maximum cell voltage difference of the tested electric vehicle power battery with time t, t is the discharge time; wherein, Q _a1 =f _a1 (t), Q _a2 =f _a2 (t), Q _a3 = f ₁₃ (t), Q _a4 =f ₁₄ (t) are the first trend formulas, ΔU _a1 =φ _a1 (t), ΔU _a2 =φ ₁₂ (t), ΔU _a3 =φ _a3 (t), ΔU _a4 = φ _a4 (t) is the second trend formula;

End the first charge-discharge cycle LOOP1 process.

In the embodiment of the present invention: Q represents the discharge capacity value of the tested electric vehicle power battery; _Qjmi represents the tested electric vehicle power when the i-th discharge is completed under the m-th environmental condition in the j-th charge-discharge cycle The discharge capacity value of the battery, for example, Q _11i represents the discharge capacity value of the tested electric vehicle power battery at the i-th discharge under the first environmental condition in the first charge-discharge cycle; ΔU represents the tested electric vehicle power battery The maximum voltage difference of the vehicle power battery; ΔU _jmi represents the maximum voltage difference of the tested electric vehicle power battery when the i-th discharge is completed under the m-th environmental condition in the j-th charge-discharge cycle, for example, ΔU _11i represents the maximum voltage difference of the tested electric vehicle power battery when the i-th discharge is completed under the first environmental condition in the first charge-discharge cycle.

In the above method, the first trend formula and the second trend formula are used to iteratively calculate the subsequent performance of the tested electric vehicle power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition. The discharge capacity of the tested electric vehicle power battery for the charge-discharge cycle and the maximum cell voltage difference of the tested electric vehicle power battery, including:

In the first charge-discharge cycle LOOP1, the last complete discharge capacity value Q _14n and the maximum cell voltage difference ΔU _14n in the fourth environmental condition stage are taken as the values of the first environmental condition stage of the second charge-discharge cycle LOOP2. The first discharge capacity value Q ₂₁₁ and the value of the maximum voltage difference ΔU ₂₁₁ of the single cell in the electric vehicle power battery tested for the first time (that is, the value of Q _14n is assigned to Q ₂₁₁ , and the value of ΔU _14n is assigned to ΔU ₂₁₁ , namely Q ₂₁₁ =Q _14n , ΔU ₂₁₁ =ΔU _14n ), according to the approximate formula Q _a1 =f of the first environmental condition stage, the second environmental condition stage, the third environmental condition stage and the fourth environmental condition stage _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 =f _a2 (t) and ΔU _a2 =φ ₁₂ (t), Q _a3 =f ₁₃ (t) and ΔU _a3 =φ _a3 (t), Q _a4 = f ₁₄ (t) and ΔU _a4 = φ _a4 (t), the last full discharge capacity Q _24n and the maximum single discharge capacity Q 24n of the fourth ambient condition stage in the second charge-discharge cycle LOOP2 are derived from Q ₂₁₁ and ΔU ₂₁₁ body voltage difference ΔU _24n ;

The above-mentioned iterative calculation is repeatedly used to sequentially obtain the last complete discharge capacity value and the maximum cell voltage difference value of the fourth environmental condition stage in each charge-discharge cycle after the second charge-discharge cycle LOOP2.

Among them, in Q _14n and ΔU _14n , n represents the number of the last discharge, 14n represents the nth (ie the last) discharge under the fourth environmental condition in the first charge-discharge cycle, and Q _14n represents the first The discharge capacity value of the tested electric vehicle power battery after the nth (ie the last) discharge under the fourth environmental condition in a charge-discharge cycle, ΔU _14n represents the fourth environment in the first charge-discharge cycle The maximum cell voltage difference of the tested electric vehicle power battery when the nth (ie the last) discharge is completed under the conditions. In Q ₂₁₁ and ΔU ₂₁₁ , 211 indicates the first discharge under the first environmental condition in the second charge-discharge cycle, and Q ₂₁₁ indicates the first discharge under the first ambient condition in the second charge-discharge cycle The discharge capacity value of the tested electric vehicle power battery when charging, ΔU ₂₁₁ represents the maximum cell of the tested electric vehicle power battery at the first discharge under the first environmental condition in the second charge-discharge cycle voltage difference.

In the embodiment of the present invention, the cycle of winter, spring, summer, and autumn is simulated throughout the year, and then the objective environment in the cycle of the year after year during the use of the electric vehicle power battery is simulated, and the environment of the four seasons is simulated. Among the conditions, the most important ones are temperature and humidity. Furthermore, in the embodiment of the present invention, the first environmental condition simulates a winter environmental state, that is, the first environmental condition corresponds to the use environmental condition of the electric vehicle power battery in winter, and the first environmental condition is: the constant temperature and humidity The chamber is set to a first average temperature and a first average humidity, wherein the first average temperature is the average temperature in winter, and the first average humidity is the average humidity in winter; the second environmental condition simulates the spring environment state, namely The second environmental condition corresponds to the use environmental condition of the electric vehicle power battery in spring, and the second environmental condition is: the constant temperature and humidity chamber is set to a second average temperature and a second average humidity, wherein the second average temperature is spring The second average humidity is the average humidity in spring; the third environmental condition simulates the summer environmental state, that is, the third environmental condition corresponds to the electric vehicle power battery use environmental condition in summer, and the third environmental condition is : the constant temperature and humidity chamber is set to a third average temperature and a third average humidity, wherein the third average temperature is the average temperature in summer, and the third average humidity is the average humidity in summer; is the autumn environment state, that is, the fourth environment condition corresponds to the use environment condition of the electric vehicle power battery in autumn, and the fourth environment condition is: the constant temperature and humidity chamber is set to the fourth average temperature and the fourth average humidity, wherein, The fourth average temperature is the average temperature in autumn, and the fourth average humidity is the average humidity in autumn.

Hereinafter, the present invention will be described again.

First, connect the device according to the above-mentioned embodiment of the electric vehicle power battery life test device. After the connection is complete, the electric vehicle power battery life test can be performed. The test process is as follows.

Open the constant temperature and humidity chamber, and set four average temperatures and average humidity to simulate winter, spring, summer and autumn in turn according to Table 1.

Table 1 Circular table

In Table 1, the ambient temperature is set by a constant temperature and humidity chamber, and the time for the temperature applied in each stage (step) of the following 1, 2, 3, and 4 accounts for 1/4 of the total time. Among them, in stage 1 (ie, step 1), the ambient temperature of T1 is the lowest temperature allowed by the battery (considering the lowest limit temperature that the electric vehicle power battery can normally use), which is used to imitate the ambient temperature in winter; in stage 2 ( That is, in step 2), the ambient temperature of T2 is normal temperature, which is used to simulate the ambient temperature in spring; in phase 3 (that is, step 3), the ambient temperature of T3 is the maximum temperature allowed by the battery (considering that the electric vehicle power battery can be normal The maximum limit temperature used) is used to imitate the ambient temperature in summer; in stage 4 (ie, step 4), the ambient temperature of T4 is normal temperature to imitate the ambient temperature in autumn, where T4=T2.

为春季平均湿度，用以模仿春季环境湿度；在阶段3(即步骤3)中，

为夏季平均湿度，用以模仿夏季环境湿度；在阶段4(即步骤4)中，

为秋季平均湿度，用以模仿秋季环境湿度。Likewise, the ambient humidity is also set by the constant temperature and humidity chamber. Among them, in stage 1 (ie step 1), is the average humidity in winter to simulate the ambient humidity in winter; in stage 2 (ie, step 2),

is the average humidity in spring to simulate the environmental humidity in spring; in stage 3 (ie step 3),

is the average humidity in summer to simulate the ambient humidity in summer; in stage 4 (ie, step 4),

It is the average humidity in autumn, which is used to simulate the environmental humidity in autumn.

In Table 1, regarding the charging and discharging conditions, the charging and discharging depth is 100% DOC/DOD, that is, it is fully charged every time and completely discharged every time. DOC is Depth Of Charge, depth of charge, DOD is Depth Of Discharge, depth of discharge, each time is charged and discharged according to NEDC (New European Driving Cycle, New European Driving Cycle) or measured conditions.

In Table 1, with regard to the vibration conditions, the vibration of the electric vehicle is considered when it is actually driving on the road, in which it is the superimposed vibration imposed by the traditional vehicle vibration road spectrum or the random vibration road spectrum according to the national standard.

It is further explained that the four temperatures T1, T2, T3, and T4 are the temperatures of the installation position of the power battery, which do not exceed the temperature resistance limit of the power battery.

Turn on the vibrating table and apply vibration to the tested electric vehicle power battery according to the vehicle's driving road spectrum.

环境条件下：在振动台按国标规定的NEDC工况或者自定义的道路路谱振动的情况下，对被测试的电动汽车动力电池按上述国标规定的NEDC工况或者自定义的道路路谱所转换成的充放电设备能够识别的充放电电流放电，当动力电池的电量放完时，再在所述振动台并不震动的状态下，以I_C电流(I_C为电池允许的恒流充电电流)对动力电池包充电至100％DOC(即最大SOC)，然后在振动台按国标规定的NEDC工况或者自定义的道路路谱振动的情况下，再次对被测试的电动汽车动力电池按上述国标规定的NEDC工况或者自定义的道路路谱所转换成的充放电设备能够识别的充放电电流放电，以此不断进行充放电循环。Turn on the charging and discharging equipment, charge the power battery pack to 100% DOC (that is, the maximum SOC) with the _IC current ( _IC is the constant current charging current allowed by the battery) under the condition that the vibrating table does not vibrate, and let it stand. After a period of time, according to the NEDC working conditions specified in the national standard or the custom road spectrum, it is converted into a charge and discharge current that can be recognized by the charging and discharging equipment (this current is less than the discharge limit of the tested electric vehicle power battery). Run winter mode, i.e. at T1 and

Under environmental conditions: when the vibration table vibrates according to the NEDC working conditions specified in the national standard or the custom road spectrum, the tested electric vehicle power battery is tested according to the NEDC working conditions specified in the above national standard or the custom road spectrum. The converted charging and discharging equipment can discharge the charging and discharging current that can be recognized. When the power of the power battery is discharged, and the vibration table does not vibrate, charge the battery with the _IC current ( _IC is the constant current allowed by the battery. current) to charge the power battery pack to 100% DOC (that is, the maximum SOC), and then under the condition that the shaking table vibrates according to the NEDC working conditions specified by the national standard or the custom road spectrum vibration, the tested electric vehicle power battery is pressed again. The charging and discharging currents that can be recognized by the charging and discharging equipment converted from the NEDC working conditions specified in the above national standards or the custom road spectrum, so as to continuously perform charging and discharging cycles.

Use the control computer to collect the dynamic signals of the voltage and current of the tested electric vehicle power battery during the above charging and discharging process with time, and calculate the discharge capacity Q _11i and the maximum single discharge capacity of the tested electric vehicle power battery when it is discharged to the lowest discharge limit each time. The bulk voltage difference ΔU _11i and the time t _11i and the total duration t are recorded. Among them, regarding the time t _jmi , where t _jmi represents the time when the i-th discharge is completed under the m-th environmental condition in the j-th charge-discharge cycle, for example, t _11i represents the time under the first environmental condition in the first charge-discharge cycle The time when the battery is discharged for the i-th time.

环境条件下，当放电容量Q_11i随着t_11i变化的曲线出现下降趋势时，按照以上方法运行春季模式，即在T2和环境条件下执行上述充放电过程，并记录上述充放电过程的电压、电流随时间变化的动态信号，计算被测试的电动汽车动力电池每次放电到最低放电极限的放电容量Q_12i和最大单体电压差ΔU_12i，并记录时间t_12i以及记录总持续时间t。其中，T2和环境条件下的充放电运行时间与T1和

环境条件下的充放电运行时间相同。at T1 and

Under ambient conditions, when the curve of the discharge capacity Q _11i with t _11i shows a downward trend, run the spring mode according to the above method, that is, at T2 and Execute the above-mentioned charging and discharging process under environmental conditions, and record the dynamic signals of the voltage and current changing with time during the above-mentioned charging and discharging process, and calculate the discharge capacity Q _12i and the maximum cell of the tested electric vehicle power battery when it is discharged to the lowest discharge limit each time. voltage difference ΔU _12i and record time t _12i as well as record total duration t. where T2 and The charge-discharge run time under ambient conditions is related to T1 and

Charge and discharge run times are the same under ambient conditions.

环境条件下的充放电运行结束时，按照以上方法运行夏季模式，即在T3和

环境条件下执行上述充放电过程，并记录上述充放电过程的电压、电流随时间变化的动态信号，计算被测试的电动汽车动力电池每次放电到最低放电极限的放电容量Q_13i和最大单体电压差ΔU_13i，并记录时间t_13i以及记录总持续时间t。其中，T3和

环境条件下的充放电运行时间与T1和

环境条件下的充放电运行时间相同。at T2 and

At the end of the charge and discharge operation under ambient conditions, run the summer mode as above, that is, at T3 and

Execute the above-mentioned charging and discharging process under environmental conditions, and record the dynamic signals of the voltage and current changing with time during the above-mentioned charging and discharging process, and calculate the discharge capacity Q _13i and the maximum cell of the tested electric vehicle power battery when it is discharged to the lowest discharge limit each time. voltage difference ΔU _13i and record time t _13i as well as record total duration t. Among them, T3 and

The charge-discharge run time under ambient conditions is related to T1 and

Charge and discharge run times are the same under ambient conditions.

环境条件下的充放电运行结束时，按照以上方法运行秋季模式，即在T4和

环境条件下执行上述充放电过程，并记录上述充放电过程的电压、电流随时间变化的动态信号，计算被测试的电动汽车动力电池每次放电到最低放电极限的放电容量Q_14i和最大单体电压差ΔU_14i，并记录时间t_14i以及记录总持续时间t。其中，T4和

环境条件下的充放电运行时间与T1和

环境条件下的充放电运行时间相同。at T3 and

At the end of the charging and discharging operation under ambient conditions, run the autumn mode according to the above method, that is, at T4 and

Execute the above charging and discharging process under environmental conditions, and record the dynamic signals of the voltage and current changing with time during the above charging and discharging process, and calculate the discharge capacity Q _14i and the maximum cell of the tested electric vehicle power battery when it is discharged to the lowest discharge limit each time. voltage difference ΔU _14i and record time t _14i as well as record total duration t. Among them, T4 and

The charge-discharge run time under ambient conditions is related to T1 and

Charge and discharge run times are the same under ambient conditions.

环境条件阶段、T2和

环境条件阶段、T3和

环境条件阶段、T4和

环境条件阶段)的近似公式Q_a1＝f_a1(t)和ΔU_a1＝φ_a1(t)、Q_a2＝f_a2(t)和ΔU_a2＝φ₁₂(t)、Q_a3＝f₁₃(t)和ΔU_a3＝φ_a3(t)、Q_a4＝f₁₄(t)和ΔU_a4＝φ_a4(t)，其中，After the above steps are completed, each stage (i.e. T1 and

Ambient condition stage, T2 and

Ambient Conditions Phase, T3 and

Ambient condition stage, T4 and

The approximate formulas for the environmental condition stage) Q _a1 =f _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 =f _a2 (t) and ΔU _a2 =φ ₁₂ (t), Q _a3 =f ₁₃ (t) ) and ΔU _a3 =φ _a3 (t), Q _a4 =f ₁₄ (t) and ΔU _a4 =φ _a4 (t), where,

环境条件下的被测试的电动汽车动力电池的放电容量随时间变化的值，ΔU_a1为T1和

环境条件下的被测试的电动汽车动力电池的最大单体电压差随时间t变化的值，Q_a2为T2和

环境条件下的被测试的电动汽车动力电池的放电容量随时间t变化的值，ΔU_a2为T2和

环境条件下的被测试的电动汽车动力电池的最大单体电压差随时间t变化的值，Q_a3为T3和

环境条件下的被测试的电动汽车动力电池的放电容量随时间t变化的值，ΔU_a3为T3和

环境条件下的被测试的电动汽车动力电池的最大单体电压差随时间t变化的值，Q_a4为T4和

环境条件下的被测试的电动汽车动力电池的放电容量随时间t变化的值，ΔU_a4为T4和

环境条件下的被测试的电动汽车动力电池的最大单体电压差随时间t变化的值，t为放电时间。其中，拟合可采用数字处理软件例如excel等工具进行。In this embodiment, Q _a1 is T1 and

The value of the discharge capacity of the tested electric vehicle power battery over time under ambient conditions, ΔU _a1 is T1 and

The maximum cell voltage difference of the tested electric vehicle power battery under ambient conditions changes with time t, Q _a2 is T2 and

The value of the discharge capacity of the tested electric vehicle power battery changing with time t under ambient conditions, ΔU _a2 is T2 and

The maximum cell voltage difference of the tested electric vehicle power battery under ambient conditions changes with time t, Q _a3 is T3 and

Under ambient conditions, the discharge capacity of the tested electric vehicle power battery changes with time t, ΔU _a3 is T3 and

The maximum cell voltage difference of the tested electric vehicle power battery under ambient conditions changes with time t, Q _a4 is T4 and

Under ambient conditions, the discharge capacity of the tested electric vehicle power battery changes with time t, ΔU _a4 is T4 and

The value of the maximum single-cell voltage difference of the tested electric vehicle power battery under environmental conditions that changes with time t, where t is the discharge time. Wherein, the fitting can be performed using tools such as digital processing software such as excel.

So far, a complete first charge-discharge cycle LOOP1 has been completed. After that, the relevant calculations for each subsequent charge-discharge cycle will be obtained by derivation.

环境条件阶段的最后一个完整的放电容量Q_24n及最大单体电压差△U_24n：Derivation of T4 and

The last complete discharge capacity Q _24n and the maximum cell voltage difference ΔU _24n in the ambient condition stage:

环境条件阶段最后一个完整的放电容量Q_14n及最大单体电压差△U_14n外推第二充放电循环LOOP2的T1和

环境条件阶段的第一个放电容量Q₂₁₁和第一个最大单体电压差△U₂₁₁，即Q₂₁₁＝Q_14n，△U₂₁₁＝△U_14n，按照以上的分段拟合公式Q_a1＝f_a1(t)和ΔU_a1＝φ_a1(t)、Q_a2＝f_a2(t)和ΔU_a2＝φ₁₂(t)、Q_a3＝f₁₃(t)和ΔU_a3＝φ_a3(t)、Q_a4＝f₁₄(t)和ΔU_a4＝φ_a4(t)推导出第二充放电循环LOOP2中T4和

环境条件阶段最后一个完整的放电容量Q_24n和最大单体电压差△U_24n。With the first charge-discharge cycle in LOOP1, T4 and

The last complete discharge capacity Q _14n and the maximum cell voltage difference ΔU _14n in the environmental condition stage extrapolate the T1 and the second charge-discharge cycle LOOP2

The first discharge capacity Q ₂₁₁ and the first maximum cell voltage difference ΔU ₂₁₁ in the environmental condition stage, that is, Q ₂₁₁ =Q _14n , ΔU ₂₁₁ =ΔU _14n , according to the above segmented fitting formula Q _a1 = f _a1 (t) and ΔU _a1 =φ _a1 (t), Q _a2 =f _a2 (t) and ΔU _a2 =φ ₁₂ (t), Q _a3 =f ₁₃ (t) and ΔU _a3 =φ _a3 (t) , Q _a4 =f ₁₄ (t) and ΔU _a4 =φ _a4 (t) to derive T4 and T4 in the second charge-discharge cycle LOOP2

The last complete discharge capacity Q _24n and the maximum cell voltage difference ΔU _24n in the ambient condition stage.

环境条件阶段的最后一个完整的放电容量Q_24n及最大单体电压差△U_24n的计算方法，依次类推直到最后一个充放电循环LOOP_Z中放电容量Q_Zmi(除了T1和

环境条件阶段以外的其它环境条件阶段的放电容量)接近被测试的电动汽车动力电池允许的放电容量或者最大单体电压差△U_Zmi(除了T1和环境条件阶段以外的其它环境条件阶段的最大单体电压差)接近允许的最大电压差时，停止推导。取Q_Zmi、△U_Zmi两者其中最先达到规定允许值的那个时间作为计算基准，此基准之前所有循环时间的累加(即总持续时间t，包括第一充放电循环LOOP1中的总时间加上后续各个充放电循环外推的总时间)即是被测试的电动汽车动力电池的预估寿命时间t_life，t_life时间内所包含的所有NEDC(或实测工况)里程的累加，即为寿命里程S_life。T4 and T4 in the second charge-discharge cycle LOOP2 are derived as above

The calculation method of the last complete discharge capacity Q _24n and the maximum cell voltage difference ΔU _24n in the environmental condition stage, and so on until the discharge capacity Q _Zmi in the last charge and discharge cycle LOOP _Z (except for T1 and

The discharge capacity of the environmental condition stage other than the environmental condition stage) is close to the discharge capacity allowed by the tested electric vehicle power battery or the maximum cell voltage difference △U _Zmi (except T1 and The derivation is stopped when the maximum cell voltage difference in the environmental condition stage other than the environmental condition stage) is close to the maximum allowable voltage difference. Take the time when Q _Zmi and △U _Zmi reach the specified allowable value first as the calculation benchmark, and the accumulation of all cycle times before this benchmark (that is, the total duration t, including the total time in the first charge-discharge cycle LOOP1 plus The extrapolated total time of each subsequent charge-discharge cycle) is the estimated life time t _life of the electric vehicle power battery to be tested, and the accumulation of all NEDC (or measured operating conditions) mileage included in the t _life time is Life mileage S _life .

If NEDC is adopted, then S _life = 11.023×N (unit is km, 11.023 is the mileage corresponding to each NEDC working condition, and N is the number of NEDCs included in the whole t _life time).

Iterative calculations in LOOP1, LOOP2... LOOP _Z can be performed by computer programming to avoid the tedious manual calculation.

The electric vehicle power battery life testing device and method of the present invention comprehensively considers comprehensive factors such as changes in temperature and humidity in spring, summer, autumn and winter, charging and discharging conditions, depth of charge and discharge, and vibration conditions, and basically includes electric At the same time, the aging extrapolation formula is fitted and the corresponding life is deduced by using the invariable failure mechanism of the material within the limit range, so it is a relatively accurate life evaluation test model. It intercepts some stages in the life decline process, thus greatly shortening the test time. The invention is simple, easy to implement, and practical.

It should be understood that the documents cited herein are for informational purposes only and do not contain any content which may conflict with that herein.

It should be understood that although this specification is described according to various embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Changes, such as combination, division or repetition of features, should be included within the scope of protection of the present invention.

Claims (6)

1. A method for testing the service life of a power battery of an electric automobile adopts a service life testing device of the power battery of the electric automobile, which comprises a vibration table, a constant temperature and humidity chamber, charging and discharging equipment and a control computer, wherein the power battery of the electric automobile to be tested is fixedly arranged on the vibration table; the vibration table and an electric automobile power battery fixedly arranged on the vibration table are arranged in the constant temperature and humidity chamber together; the charging and discharging equipment is positioned outside the constant temperature and humidity chamber and is electrically connected to the tested electric automobile power battery so as to charge and discharge the electric automobile power battery and record the voltage, the current and the temperature of the electric automobile power battery; the control computer is positioned outside the constant temperature and humidity chamber and is electrically connected with the vibration table and the charging and discharging equipment so as to control the vibration table to vibrate according to the set frequency, acceleration and displacement and control the charging and discharging equipment to charge and discharge the power battery of the electric automobile and acquire battery information; the method comprises the following steps:

respectively setting a first environmental condition, a second environmental condition, a third environmental condition and a fourth environmental condition;

simulating the vibration of the automobile during running by using a vibration table;

when the vibration table vibrates, sequentially performing first charge-discharge cycle operation on the tested electric automobile power battery under a first environment condition, a second environment condition, a third environment condition and a fourth environment condition, and acquiring a first trend formula of the change of the discharge capacity of the tested electric automobile power battery along with time in the first charge-discharge cycle operation and a second trend formula of the change of the maximum monomer voltage difference of the tested electric automobile power battery along with time;

iteratively calculating the discharge capacity of the tested electric automobile power battery and the maximum monomer voltage difference of the tested electric automobile power battery in subsequent charge-discharge cycles of the tested electric automobile power battery under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence by utilizing the first trend formula and the second trend formula;

stopping iterative computation when the discharge capacity calculated in an iterative way reaches a preset discharge capacity threshold value or when the maximum monomer voltage difference calculated in an iterative way reaches a preset voltage difference threshold value;

when the iterative computation is stopped, the accumulated time of all the cycles is used as the estimated service life of the tested electric automobile power battery, and the automobile driving mileage corresponding to the vibration spectral line of the vibration table in the estimated service life of the tested electric automobile power battery is used as the estimated service life mileage of the tested electric automobile power battery;

the first environmental condition is: the constant temperature and humidity chamber is set to a first average temperature and a first average humidity;

the second environmental condition is: the constant temperature and humidity chamber is set to a second average temperature and a second average humidity;

the third environmental condition is: the constant temperature and humidity chamber is set to a third average temperature and a third average humidity;

the fourth environmental condition is: the constant temperature and humidity chamber is set to a fourth average temperature and a fourth average humidity;

the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition respectively correspond to the using environmental conditions of the power battery of the electric automobile in winter, spring, summer and autumn.

2. The method for testing the service life of the power battery of the electric automobile according to claim 1, wherein the first charge-discharge cycle operation is performed on the tested power battery of the electric automobile under a first environmental condition, a second environmental condition, a third environmental condition and a fourth environmental condition in sequence, and a first trend formula of the discharge capacity of the tested power battery of the electric automobile in the first charge-discharge cycle operation changing along with time and a second trend formula of the maximum monomer voltage difference of the tested power battery of the electric automobile changing along with time are obtained, and the method comprises the following steps:

the first charge-discharge cycle LOOP1 process is performed:

under first environmental conditions, the following process of steps a to c is performed:

step a, starting the charging and discharging equipment under the condition that the vibration table does not vibrate, and charging the tested power battery of the electric automobile to the maximum SOC by using Ic current;

b, starting the vibration table to enable the vibration table to apply vibration to the tested electric automobile power battery according to the power battery vibration spectral line when the automobile runs, discharging the electric automobile power battery by using the charging and discharging equipment, and charging the tested electric automobile power battery to the maximum SOC by using Ic current under the condition that the vibration table is not vibrated when the electric quantity of the power battery is discharged;

and c, repeating the discharging and charging process of the step b, collecting the voltage and the current of the tested electric automobile power battery in the discharging and charging process of the step b, and calculating the discharging capacity value Q of the tested electric automobile power battery when the discharging of the tested electric automobile power battery is finished each time_11iAnd the maximum voltage difference value delta U of the single battery in the tested electric automobile power battery_11iAnd recording the total time t, wherein i represents the number of discharges;

under the first environmental condition, when the obtained discharge capacity Q is calculated_11iWhen the descending trend appears, the processes of the step b and the step c are executed under a second environmental condition, wherein the time length for executing the processes of the step b and the step c under the second environmental condition is the same as the time length for executing the processes of the step b and the step c under the first environmental condition;

after the processes of the step b and the step c are executed under the second environmental condition, the processes of the step b and the step c are continuously executed under a third environmental condition, wherein the time length for executing the processes of the step b and the step c under the third environmental condition is the same as the time length for executing the processes of the step b and the step c under the first environmental condition;

after the processes of the step b and the step c are executed under the third environmental condition, the processes of the step b and the step c are continuously executed under a fourth environmental condition, wherein the time length for executing the processes of the step b and the step c under the fourth environmental condition is the same as the time length for executing the processes of the step b and the step c under the first environmental condition;

respectively fitting approximate formulas Q of a first environmental condition stage, a second environmental condition stage, a third environmental condition stage and a fourth environmental condition stage_a1＝f_a1(t) and. DELTA.U_a1＝φ_a1(t)、Q_a2＝f_a2(t) and. DELTA.U_a2＝φ₁₂(t)、Q_a3＝f₁₃(t) and. DELTA.U_a3＝φ_a3(t)、Q_a4＝f₁₄(t) and. DELTA.U_a4＝φ_a4(t) wherein Q_a1Is the value of the discharge capacity of the tested electric automobile power battery in the first environmental condition along with the time change, delta U_a1The value Q of the maximum single voltage difference of the tested electric automobile power battery under the first environmental condition along with the change of time t_a2Is the value of the discharge capacity of the tested electric automobile power battery under the second environmental condition, delta U_a2The value Q of the maximum monomer voltage difference of the tested electric automobile power battery under the second environmental condition along with the change of the time t_a3Is the value of the discharge capacity of the tested electric automobile power battery under the third environmental condition along with the change of the time t, delta U_a3The value Q of the maximum monomer voltage difference of the tested electric automobile power battery under the third environmental condition along with the change of time t_a4Is the value of the discharge capacity of the tested electric automobile power battery under the fourth environmental condition along with the change of the time t, delta U_a4The maximum monomer voltage difference of the tested electric automobile power battery under the fourth environmental condition is a value changing along with time t, wherein t is discharging time;

the first charge-discharge cycle LOOP1 process is ended.

3. The method for testing the service life of the power battery of the electric automobile according to claim 2, wherein the step of iteratively calculating the discharge capacity of the tested power battery of the electric automobile and the maximum cell voltage difference of the tested power battery of the electric automobile in subsequent charge and discharge cycles of the tested power battery of the electric automobile under the first environmental condition, the second environmental condition, the third environmental condition and the fourth environmental condition in sequence by using the first trend formula and the second trend formula comprises the following steps:

the last full discharge capacity value Q of the fourth period of ambient conditions in the first charge-discharge cycle LOOP1_14nAnd the maximum cell voltage difference value DeltaU_14nAs the first secondary discharge capacity value Q of the first ambient condition phase of the second charge-discharge cycle LOOP2₂₁₁And the maximum voltage difference value delta U of the single battery in the electric automobile power battery tested for the first time₂₁₁According to the approximate formula Q of the first environmental condition stage, the second environmental condition stage, the third environmental condition stage and the fourth environmental condition stage_a1＝f_a1(t) and. DELTA.U_a1＝φ_a1(t)、Q_a2＝f_a2(t) and. DELTA.U_a2＝φ₁₂(t)、Q_a3＝f₁₃(t) and. DELTA.U_a3＝φ_a3(t)、Q_a4＝f₁₄(t) and. DELTA.U_a4＝φ_a4(t) from Q₂₁₁And Δ U₂₁₁The last complete discharge capacity Q of the fourth period of ambient conditions in the second charge-discharge cycle LOOP2 was derived_24nAnd the maximum cell voltage difference Δ U_24n；

The above calculation is repeated to sequentially obtain the last complete discharge capacity value and the maximum cell voltage difference value of the fourth environmental condition stage in each charge-discharge cycle after the second charge-discharge cycle LOOP 2.

4. The method for testing the service life of the power battery of the electric automobile according to claim 1, characterized in that:

the charging and discharging equipment is connected to the electric automobile power battery through a main cable so as to charge and discharge the electric automobile power battery; and the number of the first and second electrodes,

the charging and discharging equipment is connected with the electric automobile power battery through a voltage acquisition line, a current acquisition line and a temperature acquisition line so as to acquire voltage, current and temperature information of the electric automobile power battery.

5. The method for testing the service life of the power battery of the electric automobile according to claim 1, characterized in that:

the battery information comprises voltage, current and temperature information of the power battery of the electric automobile.

6. The method for testing the service life of the power battery of the electric automobile according to claim 1, characterized in that:

the control computer is connected with the charging and discharging equipment through a data line so as to obtain the battery information through the data line and determine the service life of the tested power battery of the electric automobile by utilizing the battery information.

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