CN115079018A - Electrical performance test method for lithium ion battery for manned submersible vehicle - Google Patents

Abstract

The invention discloses an electrical performance test method of a lithium ion battery which is suitable for bearing pressure in a full-sea-depth range used by a manned submersible, wherein the electrical performance of the lithium ion battery in a pressure-bearing state is pre-judged by taking the discharge capacity and the alternating-current ohmic internal resistance of the battery as main judgment bases through a pressure simulation device simulation test and a normal-pressure electrical performance test; by the testing method, whether the lithium ion battery monomer has effective discharge in the full-sea deep pressure range can be quickly and simply evaluated, and safe and reliable energy power guarantee is provided for safe operation of the ten-thousand-meter pressure-bearing deep-sea manned submersible vehicle in the pressure range of 0-11000 meters of seawater.

Description

A method for testing the electrical properties of lithium-ion batteries for manned submersibles

technical field

The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrical performance detection method of a self-supporting lithium ion battery for manned submersibles suitable for full-sea deep operation.

Background technique

Lithium-ion batteries have become the most potential deep-sea equipment batteries due to their high specific energy and high specific power characteristics. Replacing traditional silver-zinc batteries for deep-sea submersibles with lithium-ion batteries can greatly improve the endurance and electrical load capacity of deep-sea equipment. . However, whether lithium-ion batteries can withstand the huge seawater pressure in the deep sea is the primary problem that restricts their application in deep-sea equipment.

At present, lithium-ion batteries used in deep-sea equipment mainly adopt two pressure-bearing methods: (1) relying on the pressure-bearing shell to bear pressure; (2) lithium-ion batteries are directly pressure-bearing. The heavy shell required by the former greatly reduces the mass ratio of the entire battery system, making it difficult to meet the needs of deep-sea equipment development. Due to the direct pressure of lithium-ion batteries, the latter has high requirements for battery technology, and its ability to withstand deep-sea pressure is not yet clear.

How to investigate whether a lithium-ion battery with a pressure-resistant design can really withstand the complex pressure environment in the deep sea and ensure the safe operation of deep-sea submersibles in the entire depth of the sea has become one of the bottleneck technologies in deep-sea battery technology.

The manned submersible is the equipment with the highest requirements for the reliability of the electrical performance of the lithium-ion battery in the deep-sea equipment. When used as the main power, the stability of its electrical performance directly determines whether the submersible can return to the voyage smoothly. According to the current use requirements of manned submersibles around the world, the electrical performance requirements of lithium-ion batteries are met: (1) It can be discharged normally for a long time in a hydrostatic pressure environment of 0-115MPa; (2) The discharge temperature matches the deep-sea low temperature environment ; (3) The ability to withstand the pressure change rate adapting to the working conditions of the manned submersible.

In order to ensure the reliability of the submersible's power consumption, the electrical properties of the battery need to be strictly tested after the preparation of the lithium-ion battery under pressure. The number of piezoelectric performance testing is more than 30 times, and the single withstand voltage testing time is long, which makes the entire electrical performance testing cycle long, and the human and material resources are consumed in the testing process. This is one of the important reasons why the manufacturing cost of lithium-ion batteries for manned submersibles is much higher than that of conventional lithium-ion batteries.

However, speeding up the electrical performance testing and screening cycle and reducing the number of withstand voltage tests will reduce the reliability of the test for the withstand voltage performance of lithium-ion batteries. Therefore, in order to reduce the manufacturing cost of deep-sea pressurized lithium-ion batteries and ensure the reliability and non-destructiveness of electrical performance testing, it is urgent to solve the above technical contradictions.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a method for testing the electrical performance of a lithium-ion battery that is suitable for use in manned submersibles under pressure in the full sea depth range.

The technical solution adopted by the present invention to solve the technical problem is as follows: a method for testing the electrical performance of lithium ion batteries for manned submersibles, the ohmic internal resistance R tested by the method is a lithium ion battery cell with a _{normal pressure} of 1mΩ～2mΩ, It has the ability to work under pressure directly in the water pressure or seawater pressure environment of 0 to 11,000 meters, and can meet the transformation load of the maximum limit transformation rate of 2MPa/min. The specific pressure resistance test process includes the following steps:

The first step is to visually inspect the appearance of the lithium-ion battery, which must meet the requirements of no particles on the surface of the battery, no traces of electrolyte, no wrinkles, no damage and no deformation;

In the second step, the AC impedance spectrum test is performed on the battery cell in the fully charged state, and the ohmic impedance R _{normal pressure} related to the transportation of lithium ions and electrons through the electrolyte, porous separator, and active material particles in the lithium ion battery is obtained, R _{normal pressure} Should be between 1mΩ ~ 2mΩ;

The third step is to conduct a low-temperature electrical performance test at about 0°C for the fully charged lithium-ion battery: the normal pressure low-temperature test and the 127MPa low-temperature electrical performance test for a time, a≥5, the battery capacity before and after the test must meet the Q _{withstand voltage a} /Q _{normal pressure} ≥ 99%, and AC ohmic impedance R satisfies 0.5≤R _{withstand voltage a/R normal pressure≤0.9} .

Further, the low-temperature electrical performance test at about 0°C should be performed at a temperature of -4 to 5°C, and the electrical performance test at normal pressure should be performed in an environment with a relative humidity of 25 to 85% and an air pressure of 90 to 108 kPa, and a resistance of 127 MPa. The cryogenic test should be carried out in a simulated pressure cylinder, including the following steps:

Step 1: According to the rated capacity of the lithium-ion battery, charge the battery with constant current at a rate of 0.2C. After charging to the rated cut-off voltage, stop charging and let the battery stand for ≥30 minutes. Connect the battery to the AC impedance test. device, perform AC impedance spectrum scanning under open circuit voltage conditions, the AC frequency scanning range should not be lower than 0.01Hz ~ 0.1MHz, test the ohmic internal resistance R obtained after fitting the AC impedance spectrum, and the fitting accuracy of the spectrum should be above 90%;

The second step is to discharge the lithium-ion battery with a constant current current of 0.2C of the rated capacity, and stop after discharging to the rated discharge cut-off voltage to obtain the normal pressure discharge capacity Q _{normal pressure} ;

The third step, according to the first step, the same constant current charging method to fully charge the lithium-ion battery and then stand still, the resting time is ≥ 30 minutes;

Step 4, place the lithium-ion battery in the pressure simulation device, and connect the positive and negative electrodes to the external circuit;

Step 5, start the pressure simulation device, pressurize to 127MPa at the pressurizing rate S1=0～2MPa/min, and keep the pressure T1≥310 minutes;

In step 6, when the pressure simulation device reaches 127MPa, the lithium-ion battery performs AC impedance spectrum scanning under the condition of open circuit voltage, and the obtained ohmic internal resistance R _{withstand voltage a} , where the AC frequency scanning range and spectral fitting accuracy are the same as the first the same step;

The 7th step, under the environment of 127MPa, the lithium ion battery is discharged at a constant current rate of 0.2C at the rated capacity, and then stops after discharging to the rated discharge cut-off voltage, and the obtained a-th withstand voltage discharge capacity is recorded as Q _{withstand voltage a} ;

Step 8, the pressure simulation device is released to normal pressure at the pressure release rate S2≥1MPa/min;

Step 9, take the battery out of the pressure simulation device and let it stand for 30 minutes;

Step 10: Repeat steps 3 to 9 for a times, a ≥ 5 times.

Further, the lithium-ion battery is a ternary nickel-cobalt-manganese battery, a ternary nickel-cobalt-aluminum battery, a lithium iron phosphate, a lithium titanate battery or a lithium-rich battery.

The beneficial effects of the present invention are:

Through the testing method of the present invention, the ability of lithium-ion batteries to be equipped with manned submersibles to complete effective electric energy supply can be quickly and easily predicted and evaluated. Or in the seawater pressure environment, the bearing pressure reaches 114MPa, and the maximum ultimate pressure capacity reaches 127MPa, and the load discharge can be safely cycled.

The method can provide a safe and reliable energy and power guarantee for the safe operation of the manned submersible in the pressure range of 0-11000 meters of seawater. It can be used as a power battery in deep-sea manned submersibles, and can also be used in other deep-sea unmanned submersibles, deep-sea preset platforms, etc., as well as deep-sea underwater robots, deep-sea power stations, deep-sea communication base stations and other fields, but not limited to this.

Description of drawings

Fig. 1 is the comparison between the normal pressure impedance and the fitting result before the fully charged battery cell in Example 1 of the present invention;

FIG. 2 is the boost curve of the pressure device in the test process of the withstand voltage performance of the battery cell in Example 1 of the present invention.

Detailed ways

The present invention finds the following conditions for the preparation of tens of thousands of lithium-ion batteries for manned submersibles, the assessment of the withstand voltage performance, and the data summarizing the feedback of the batteries with the actual flight electrical performance of the "Striver" submersible:

(1) After the continuous low temperature environment of the manned submersible and the thermal field generated by the operation of the supporting power battery pack under different working conditions, the actual operating environment temperature of the lithium-ion battery is between 0 and 5 °C, and combined with the flexible bearing of the 127MPa lithium-ion battery. Based on the low-temperature transport characteristics of lithium ions exhibited by the linear small-molecule electrolyte formulation in the pressure structure, it is determined that the ambient temperature range for predicting the discharge performance of batteries for manned submersibles can be set between -4 °C and 5 °C.

(2) In-depth analysis of the actual voltage transformation rate and the ultimate tolerance of the internal pressure-bearing materials of the lithium-ion battery during the diving and ascent of manned submersibles in various countries in the world, and found that the ohmic internal resistance of the lithium-ion battery accurately fitted by the AC impedance spectrum The variation law of R _{withstand voltage} under the pressure environment of 127MPa, the design of the battery flexible pressure bearing structure and the battery capacity are closely related, and the battery flexible pressure bearing structure design is positively related to the ohmic internal resistance R _{under normal pressure} . Therefore, the boundary conditions of the above parameters can be accurately summarized through the measured data as the basis for shortening the test cycle and ensuring the reliability of the test.

The present invention is further described in detail below with reference to the examples, but is not intended to limit the protection scope of the present invention.

The relationship between the boundary conditions and the quantitative correlation of the parameters in the electrical performance test of the lithium-ion battery for manned submersibles of the present invention is achieved through the following technical solutions.

First, the ohmic internal resistance R tested by this method is a lithium-ion battery cell with a _{normal pressure} of 1mΩ to 2mΩ, which has the ability to work directly under pressure in a water pressure or seawater pressure environment of 0 to 11,000 meters, and can be To meet the transformation load with the maximum limit transformation rate of 2MPa/min, the specific withstand voltage performance test process includes the following steps.

The first step is to visually inspect the appearance of the lithium-ion battery, which must meet the requirements: no particles on the surface of the battery (including particles in the inner layer of aluminum plastic film), no traces of electrolyte, wrinkles, damage, and deformation.

In the second part, the AC impedance spectrum test is performed on the battery cell in the fully charged state, and the ohmic impedance R _{normal pressure} , R _normal pressure, related to the transportation of lithium ions and electrons through the electrolyte, porous separator, and active material particles in the lithium ion battery is obtained. Should be between 1mΩ ~ 2mΩ.

The principle is that the research of the present invention finds that the lithium-ion battery with R _{normal pressure} in this range has a high group rate in the process of matching the total energy required by the manned submersible, and the 127MPa resistance associated with the selection of raw materials in the pressure design and the battery structure design. The pressure change range can be accurately predicted, and the non-destructive pressure relaxation and stability period can be accurately shortened to 5 weeks. At the same time, when the _{normal pressure} of R is within this range, the lithium-ion battery cell can also be widely used in various manned submersibles.

The third step is to perform low-temperature electrical performance tests on the fully charged lithium-ion battery in the range of -4°C to 5°C, including the normal pressure low-temperature test and a 127MPa withstand voltage low-temperature electrical performance test. Before and after the test, the battery capacity must meet Q _{Withstand voltage a} /Q _{normal pressure} ≥ 99%, and AC ohmic impedance R satisfies: 0.5≤ R _{withstand voltage a/R normal pressure} ≤ 0.9, where a≥5.

The principle of this step is that the _{normal pressure} of R should be between 1mΩ and 2mΩ for the lithium-ion battery cell. When the R _{withstand voltage a/R normal pressure} is less than 0.5, the internal resistance microstructure of the battery cell and the theoretical calculation summary found that there is irreversible damage. The probability increases, and when the R _{withstand voltage a/R normal pressure} is greater than 0.9, the lithium-ion battery has poor withstand voltage flexibility, and the battery cycle performance will rapidly decay.

The lithium-ion battery that is subjected to the withstand voltage performance test needs to be tested in the above three steps in sequence, and must meet the test requirements at the same time, so that the lithium-ion battery can pass the electrical performance test of the lithium-ion battery for manned submersibles.

In the second aspect, the present invention provides a low-temperature electrical performance test at about 0°C as described in the first aspect above. The temperature should be -4 to 5°C, and the electrical performance test at normal pressure should be performed at a relative humidity of 25°C. ~85%, air pressure: 90 ~ 108kPa environment, 127MPa low temperature test should be carried out in a pressure simulation device (simulated pressure cylinder), including the following specific steps.

The first step is to charge the battery with a constant current at a rate of 0.2C according to the rated capacity of the lithium-ion battery. After charging to the rated cut-off voltage, stop charging and let the battery stand for ≥30 minutes. Connect the battery to the AC impedance test The device is used to perform AC impedance spectrum scanning under the condition of open circuit voltage. The AC frequency sweep range should be no less than 0.01Hz to 0.1MHz, and the ohmic internal resistance R _{normal pressure} obtained after fitting the AC impedance spectrum obtained from the test, in which the fitting accuracy of the spectrum should be above 90%.

In the second step, the lithium-ion battery is discharged with a constant current current of 0.2C rate of the rated capacity, and stops after discharging to the rated discharge cut-off voltage to obtain the normal pressure discharge capacity Q _{normal pressure} .

The third step is to fully charge the lithium-ion battery according to the same constant current charging method as the first step, and then stand still for ≥30 minutes.

In the fourth step, the lithium ion battery is placed in the pressure simulation device, and the positive and negative electrodes are externally connected to an external circuit.

The fifth step is to start the pressurization system. According to the pressurization rate of about S1, S1=(0MPa/min～2MPa/min, pressurize to 127MPa, maintain pressure for T1min, T1≥310min.

The sixth step, when the pressure simulation device reaches 127MPa, the lithium-ion battery performs AC impedance spectrum scanning under the condition of open circuit voltage, and the obtained ohmic internal resistance R _{withstand voltage a} , where the AC frequency scanning range and spectral fitting accuracy are the same as the first. same step.

In the seventh step, under the environment of 127MPa, the lithium ion battery is discharged at a constant current rate of 0.2C at the rated capacity, and stops after discharging to the rated discharge cut-off voltage. The obtained a-th withstand voltage discharge capacity is recorded as Q _{withstand voltage a} .

The eighth step, the pressure simulation device is released to normal pressure, and the pressure release rate S2, S2 ≥ 1MPa/min.

The ninth step, take out the battery from the pressure simulation device and let it stand for 30 minutes.

The tenth step is to repeat the third to the ninth step a times, a ≥ 5 times.

In the third aspect, the five cycles described in the first aspect provided by the present invention are the minimum number of times of the withstand voltage performance test, and also include more than five test cycles of the same steps.

In the fourth aspect, in the first aspect of the present invention, the boost rate and the depressurization rate, 2MPa/min is the minimum rate for the withstand voltage performance test, and also includes the rapid boost and rapid depressurization rates greater than 2MPa/min .

In the fifth aspect, the second aspect of the present invention provides constant current discharge at a rate of 0.2C at the rated capacity, where 0.2C is the minimum discharge rate for the piezoelectric withstand performance test, and also includes a discharge rate greater than 0.2C.

In the sixth aspect, the first aspect of the present invention provides a method for testing the electrical performance of lithium-ion batteries for manned submersibles, where the lithium-ion batteries are ternary nickel-cobalt-manganese batteries or ternary nickel-cobalt-aluminum batteries or iron phosphate. Lithium or Lithium Titanate battery or Lithium rich base battery.

Example 1

Select 100 full-sea deep-sea lithium iron phosphate battery cells with a specification of 48Ah (the No. 712 Research Institute of China Shipbuilding Industry Corporation) to test the withstand voltage performance. The specific operation steps are as follows:

①Use a charging and discharging cabinet (accuracy 0.01A, China Shipbuilding Industry Corporation No. 712 Research Institute) to charge the battery cell to be tested according to the charging procedure: 1 atmospheric pressure, 25 °C under the condition of 0.2C current constant current charging, Stop charging when the battery cell voltage reaches 3.60V. Let stand for 30 minutes after charging.

②Connect the charged battery cell to an AC impedance tester (frequency accuracy 0.0001Hz, maximum frequency range 2MHz), and perform AC impedance spectrum scanning under the condition of open circuit voltage. The AC frequency sweep range is set to 0.01Hz~0.1MHz, sweep from high frequency to low frequency, and simulate the spectrum after the test. The simulation results are shown in Figure 1. When the fitting accuracy reaches 95%, record the R _constant at this time. _pressure .

③ Discharge the lithium-ion battery with a constant current current of 0.2C rate of rated capacity, and stop after discharging to the rated discharge cut-off voltage to obtain the normal pressure discharge capacity Q _{normal pressure} .

④ According to the same constant current charging method as ①, fully charge the lithium-ion battery and then stand still for ≥ 30 minutes.

⑤ Put the charged battery cells into the pressure-resistant tank of the deep-sea pressure simulation device (accuracy 115MPa/2MPa), and connect the positive and negative measuring wires to the charging and discharging cabinet (accuracy 0.01A, the seventh of China Shipbuilding Industry Corporation). One or two research institutes), turn on the deep-sea pressure simulation device, pressurize to 127MPa at a pressurizing rate of 2MPa/min, and maintain the pressure for 320 minutes. The pressure rise curve is shown in Figure 2.

⑥ When the pressure simulation device reaches 127MPa, the lithium-ion battery is subjected to AC impedance spectrum scanning under the condition of open circuit voltage, and the obtained ohmic internal resistance R _{withstand voltage 1} , in which the AC frequency scanning range and spectral fitting accuracy are the same as the first step.

⑦ In the environment of 127MPa, the lithium-ion battery is discharged at a constant current rate of 0.2C at the rated capacity, and stops after discharging to the rated discharge cut-off voltage. The obtained first withstand voltage discharge capacity is recorded as Q _{withstand voltage 1} .

⑧ The pressure simulation device is released to normal pressure, and the pressure release rate is 2MPa/min.

⑨ Take the battery out of the pressure simulation device and let it stand for 30 minutes.

Repeat ④ to ⑨ 5 times to obtain the Q _{withstand voltage 5} and the R _{withstand voltage 5} for the 5th time.

Among the above 100 full-sea deep-sea lithium iron phosphate batteries, those with a Q _{withstand voltage of 5} /Q _{normal pressure} <99% are recorded as A1 type battery cells, and the rest of the battery cells are recorded as B1 type. The number distribution of various battery cells is shown in the following table (Appendix 1: The number of battery cells that passed the test after the various withstand voltage performance tests).

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Using the battery charging and discharging cabinet (accuracy 0.01A, China Shipbuilding Industry Corporation No. 712 Research Institute), the B1 battery cells are charged according to the normal pressure battery capacity of 0.2C, and the 10,000-meter manned deep-sea submersible needs Under the pressure environment of 115MPa and 127MPa, the discharge cycle test is carried out at a normal pressure battery capacity of 0.5C for 500 cycles. During the 500-cycle test, the number of battery cells whose discharge capacity of B1 battery cells drops to 32.8Ah or below is divided by the B1 battery cells. The total number of cells, denoted as C1, is shown in the following table (Appendix 2: Probability that the capacity of the battery after passing the test does not meet the requirements after 500-cycle withstand voltage cycles).

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Comparative Example 1

Select 100 full-sea deep-sea lithium iron phosphate battery cells with a specification of 48Ah (No. 712 Research Institute of China Shipbuilding Industry Corporation) to test the withstand voltage performance. The specific operation steps are as follows.

①Use a charging and discharging cabinet (accuracy 0.01A, China Shipbuilding Industry Corporation No. 712 Research Institute) to charge the battery cell to be tested according to the charging procedure: 1 atmospheric pressure, 25 °C under the condition of 0.2C current constant current charging, Stop charging when the battery cell voltage reaches 3.60V. Let stand for 30 minutes after charging.

②Put the charged battery cells into the pressure-resistant tank of the deep-sea pressure simulation device (accuracy 115MPa/0.1MPa), and connect the positive and negative measuring wires to the charging and discharging cabinet (accuracy 0.01A, China Shipbuilding Industry Corporation No. 712 Research Institute), turn on the deep-sea pressure simulation device, and carry out the withstand voltage performance test according to the following table (voltage resistance test boosting procedure).

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Lithium-ion battery cells are discharged with a constant current of 0.2C after boosting for 30 minutes, and stop discharging when the battery cell voltage reaches 2.65V, and stand for 30 minutes.

③ Repeat steps ① to ② for 50 cycles, and record the discharge capacity Q50 of the 50th time and the discharge capacity Q0 of the first time.

Among the above 100 full-sea deep-sea lithium iron phosphate batteries, those with a Q50/Q0 value of less than 98% are recorded as A2 type battery cells, and the rest of the battery cells are recorded as B2 type. The number distribution of various battery cells is shown in Table 1.

Using the battery charging and discharging cabinet (accuracy 0.01A, China Shipbuilding Industry Corporation No. 712 Research Institute), the B1 battery cells are charged according to the normal pressure battery capacity of 0.2C, and the 10,000-meter manned deep-sea submersible needs Under the pressure environment of 115MPa and 127MPa, the discharge cycle test is carried out at a normal pressure battery capacity of 0.5C for 500 cycles. During the 500-cycle test, the number of battery cells whose discharge capacity of B2 battery cells drops to 32.8Ah or below is divided by the B2 battery cells. The total number of monomers, denoted as C2, is shown in Table 2.

Example 1 and Comparative Example 1 used lithium-ion battery cells of the same specification and the same manufacturer. Attached Table 1 can illustrate that both methods can detect the voltage resistance of the battery. Example 1 of the present invention and Comparative Example of the present invention 1 The test method of withstand voltage performance provided by the test method has simpler test steps and shorter test period. Attached table 2 can illustrate that the embodiment 1 provided by the present invention has the same detection and evaluation effect compared with the comparative example 1, and the battery cells that pass the electrical performance test of the lithium-ion battery for manned submersibles provided by the first aspect of the present invention The battery capacity retention rate is ≥80% during the 500-cycle withstand voltage cycle test, and the probability of batteries that do not meet the electrical performance requirements is 0%.

It can be seen from the attached table 2 that compared with the comparative example 1, the battery tested by the withstand voltage performance test provided by the present invention has the same prediction effect as the comparative example 1, but the detection period is obviously shortened, which can greatly reduce the lithium ion used in manned submersibles. The preparation cycle and assessment time of ion batteries are of great significance to the long-cycle operation of lithium-ion batteries in the deep sea.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (3)

1. A method for testing the electrical performance of a lithium ion battery for a manned potential vehicle is characterized by comprising the following steps: comprises the following steps

Firstly, visually observing the appearance of the lithium ion battery, and meeting the requirements of no particles on the surface of the battery, no electrolyte trace, no wrinkle, no damage and no deformation;

secondly, carrying out alternating current impedance spectrum test on the battery monomer in a full-state to obtain ohmic impedance R of the lithium ion battery _{Atmospheric pressure} ，R _{Atmospheric pressure} Should be between 1m omega-2 m omega;

thirdly, testing the low-temperature electrical property of the fully-charged lithium ion battery: the normal pressure low temperature test and the a times 127MPa voltage-withstanding low temperature electrical property test show that a is more than or equal to 5, and the battery capacity before and after the test needs to meet Q _{Withstand voltage a} /Q _{Atmospheric pressure} Not less than 99%, and the AC ohmic resistance R is not less than 0.5 _{Withstand voltage a} /R _{Atmospheric pressure} ≤0.9。

2. The electrical property test method of the lithium ion battery for the manned submersible vehicle according to claim 1, characterized in that the low-temperature electrical property test is carried out in an environment with a temperature of-4 ℃ to 5 ℃, a relative humidity of 25% to 85% and an air pressure of 90 kPa to 108kPa, a 127MPa withstand voltage low-temperature test is carried out in a pressure simulation device, and the method specifically comprises the following steps:

step 1, performing constant current charging on a battery under the condition of 0.2C multiplying power according to the rated capacity of the lithium ion battery, stopping charging after the battery is charged to rated cut-off voltage, standing the battery, connecting the battery to an alternating current impedance testing device after the standing time is more than or equal to 30 minutes, performing alternating current impedance spectrum scanning under the condition of open circuit voltage, wherein the alternating current frequency scanning range is 0.01 Hz-0.1 MHz, testing the obtained ohmic internal resistance R after an alternating current impedance spectrum is fitted, and the spectrum fitting precision is more than 90%;

step 2, discharging the lithium ion battery with a constant current with a rated capacity of 0.2C, stopping discharging until a rated discharge cut-off voltage, and obtaining a normal-pressure discharge capacity Q _{Atmospheric pressure} ；

Step 3, according to the step 1, the lithium ion battery is charged and then stands still for more than or equal to 30 minutes;

step 4, placing the lithium ion battery in a pressure simulation device, and externally connecting the positive electrode and the negative electrode to an external circuit;

step 5, starting a pressure simulation device, pressurizing to 127MPa according to the pressurizing speed S1= 0-2 MPa/min, and keeping the pressure T1 for more than or equal to 310 minutes;

6, when the pressure simulator reaches 127MPa, the lithium ion battery carries out AC impedance spectrum scanning under the condition of open-circuit voltage to obtain ohmic internal resistance R _{Withstand voltage a} ；

And 7, discharging the lithium ion battery monomer at constant current with rated capacity of 0.2C under 127MPa, stopping discharging until rated discharge cut-off voltage is reached, and recording the obtained a-th withstand voltage and discharge capacity as Q _{Withstand voltage a} ；

Step 8, the pressure of the pressure simulation device is released to normal pressure according to the pressure release rate S2 which is more than or equal to 1 MPa/min;

step 9, taking the battery out of the pressure simulator, and standing for 30 minutes;

and step 10, circulating the steps 3 to 9 for a times, wherein a is more than or equal to 5 times.

3. The method for testing the electrical property of the lithium ion battery for the manned vehicle according to claim 2, wherein the lithium ion battery is a ternary nickel cobalt manganese battery, a ternary nickel cobalt aluminum battery, lithium iron phosphate, a lithium titanate battery or a lithium-rich battery.

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