A method for testing the corrosion resistance and weather resistance of automotive battery packs

Abstract

This invention first provides a method for testing the corrosion resistance and weather resistance of automotive battery packs. The method involves pre-treating the battery pack by driving it on a test vehicle under preset road conditions for a certain period. The battery pack is then disassembled and stored in an environmental chamber for a preset period. Its corrosion resistance and weather resistance are then evaluated based on the corrosion observed. This invention conducts an environmental simulation storage experiment on the pre-treated battery pack in an environmental chamber, adjusting the environmental conditions: the pre-treated high-voltage battery pack is disassembled from the vehicle and subjected to alternating temperature, humidity, and salt spray environmental simulations. This effectively examines the corrosion resistance and sealing performance of the high-voltage battery pack and its components after exposure to pollution and gravel impacts.

Description

Technical Field

[0001] This invention relates to the field of vehicle component safety protection technology, specifically to a method for testing the weather resistance performance of an automotive battery pack. Background Technology

[0002] The production and sales of new energy vehicles in the Chinese market are currently growing rapidly. As a core component of new energy vehicles, the reliability and durability of high-voltage battery packs directly affect the overall safety performance of the vehicle. Corrosion resistance and sealing performance also significantly impact the reliability and durability of high-voltage battery packs. China is a vast country with complex road conditions, with significant differences in road conditions between highways, urban roads, county roads, township roads, and village roads. Some Chinese cities suffer from severe pollution, with high levels of industrial dust and poor air quality. Prolonged driving on dusty and polluted roads in heavily polluted environments significantly corrodes the vehicle chassis, placing higher demands on the corrosion resistance of high-voltage battery packs in new energy vehicles. However, the industry currently lacks systematic testing and evaluation methods for corrosion resistance and weather resistance.

[0003] Invention Patent Content

[0004] To address the aforementioned problems, this invention provides a method for testing the corrosion and weather resistance performance of automotive battery packs. This method utilizes "battery pack road test pretreatment" and "environmental simulation storage experiment" to test the corrosion and weather resistance performance of new energy vehicle battery packs, effectively evaluating their corrosion and weather resistance. The objective of this invention is achieved through the following technical solution:

[0005] This invention first provides a method for testing the corrosion resistance and weather resistance of automotive battery packs. The method involves a test vehicle carrying the battery pack under test driving for a certain period of time under preset road conditions for pretreatment, then disassembling the battery pack and placing it in an environmental chamber for a preset period of time, and finally evaluating its corrosion resistance and weather resistance based on the corrosion condition of the battery pack.

[0006] Furthermore, the method for testing corrosion resistance and weather resistance includes:

[0007] Step S100: Use a test vehicle carrying the battery pack under test to drive at a specific speed under preset road conditions for preprocessing time;

[0008] Step S200: Disassemble the battery pack to be tested, place it in the environmental chamber, adjust the environmental conditions of the environmental chamber, and store it for a preset period under different environmental chamber conditions;

[0009] Step S300: Remove the battery pack under test from the environmental chamber, check its corrosion, and evaluate its corrosion resistance and weather resistance based on the corrosion.

[0010] Furthermore, step S100 includes:

[0011] Step S101: Mount the battery pack to be tested onto the test vehicle according to the assembly requirements;

[0012] Step S110: Perform several preprocessing loops, each preprocessing loop including:

[0013] Step S111: Control the test vehicle to travel a first preset distance on a salt water road section at a first speed, wherein the salt water concentration of the salt water road section is 2-3%;

[0014] Step S112: Control the test vehicle to travel the second preset distance at the second speed on the dusty and gravel road section;

[0015] Step S113: Control the test vehicle to travel the third preset distance on the muddy road section at idle speed.

[0016] Further, the first speed is 15-25 km / h, and the first preset distance is 40-80 m; the second speed is 45-75 km / h, and the second preset distance is 8-12 km; the third preset distance is 15-25 m. Preferably, the first speed is 20 km / h, and the first preset distance is 50 m; the second speed is 60 km / h, and the second preset distance is 10 km; the third preset distance is 20 m.

[0017] Preferably, the pretreatment cycle is repeated at least 3 times; more preferably, the pretreatment cycle is repeated at least 7 times; in a preferred embodiment, the above steps constitute one road test cycle, and the vehicle is not washed after the test; preferably, the road test cycle is performed once a day, and the above cycle is repeated 10 times to complete the road test pretreatment. Through multiple road test cycles of pretreatment, the usage scenarios of the vehicle under extreme conditions such as dust, mud, gravel, and heavy ambient air pollution can be fully simulated.

[0018] Further, step S200 includes:

[0019] Step S201: Remove the battery pack under test, which has been pre-treated in step S100, from the test vehicle and place its bottom surface into the environmental chamber at a first angle to the ground. When storing, install the interfaces of each high-voltage component according to the installation method to avoid leakage from the interface position.

[0020] Step S220: Execute several environmental condition cycles, the environmental condition cycles including:

[0021] Step S221: Adjust the environmental chamber conditions to standard climate conditions, and store the battery pack under test under these standard climate conditions for a first settling time. The standard climate conditions are 20-25°C, 50% humidity, and 3-5 hours.

[0022] Step S222: Adjust the environmental chamber conditions to salt spray conditions, and store the battery pack under test under these salt spray conditions for a second settling time. The temperature in the salt spray conditions is 32-37°C, the salt concentration is 3%, and the second settling time is 1.5-2.5 hours.

[0023] Step S223: Adjust the environmental chamber conditions to the first humid and hot condition, and store the battery pack under test under the first humid and hot condition for a third standing time. The temperature in the first humid and hot condition is 45-55°C, the humidity is 95%, and the third standing time is 6-8 hours.

[0024] Step S224: Adjust the environmental chamber conditions to dry conditions, and store the battery pack under test under these dry conditions for a fourth settling time. The dry conditions are 38-42°C, 30% humidity, and 3-5 hours.

[0025] Furthermore, step S200 also includes step S225: adjusting the ambient temperature to a second humid heat condition, and storing the battery pack under test under this second humid heat condition for a fifth standing time. The temperature in the second humid heat condition is 45-55°C, the humidity is 85%, and the fifth standing time is 6-8 hours.

[0026] Furthermore, in step S220, the environmental conditions are cycled at least 20 times, and the preset period is at least 20 days; preferably, the time to complete one environmental condition cycle is set to 24 hours; preferably, the first settling time is 4 hours, the second settling time is 2 hours, the third settling time is 7 hours, the fourth settling time is 4 hours, and the fifth settling time is 7 hours; more preferably, the number of cycles is at least 50 times, and the preset period is at least 50 days.

[0027] Furthermore, in step S201, the first included angle is 5° to 15°; preferably, the first included angle is 10°, so as to ensure that a thin water film is maintained on the surface to simulate the actual use condition, while avoiding the influence of excessive water accumulation on the surface of the battery pack on the results.

[0028] Furthermore, step S300 includes:

[0029] Step S301: Remove the battery pack to be tested from the environmental chamber;

[0030] Step S311: Check whether the functions of each external interface are normal. If the interface functions are normal, proceed to step S320.

[0031] Step S312: Detect whether there are macroscopic defects in the battery pack casing, including bubbles, pitting corrosion and perforation corrosion;

[0032] Step S313: Use electron microscopy and energy dispersive spectroscopy to detect whether there is micro-corrosion on the battery pack casing;

[0033] Step S314: Inject a preset pressure into the battery pack through the battery pack interface to check whether the airtightness of the battery pack is qualified;

[0034] Step S320: Generate a judgment result on whether the corrosion resistance and weather resistance performance of the battery pack is qualified based on the test results of steps S311 to S314.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. This invention pre-processes the battery pack under test by mounting it on a test vehicle for road testing, simulating the vehicle's usage scenarios under extreme conditions of heavy dust, mud, gravel, and severe air pollution through salt water sections, mud sections, and dusty and rock-impacted sections.

[0037] 2. This invention conducts an environmental simulation storage experiment by placing the pre-treated battery pack in an environmental chamber and adjusting the environmental conditions: the pre-treated high-voltage battery pack is disassembled from the vehicle and subjected to alternating temperature, humidity and salt spray environment simulations. This can effectively examine the corrosion resistance and sealing performance of the high-voltage battery pack and high-voltage components after being subjected to pollution and gravel impact. Attached Figure Description

[0038] Figure 1 The figure shows the temperature and humidity changes in the environmental chamber over a period of time in a preferred embodiment of the present invention. Detailed Implementation

[0039] The preferred embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] This embodiment provides a method for testing the corrosion resistance and weather resistance of automotive battery packs. The method involves pre-treating the battery pack by driving a test vehicle with the battery pack under preset road conditions for a certain period of time, disassembling the battery pack and storing it in an environmental chamber for a preset period of time, and then evaluating its corrosion resistance and weather resistance based on the corrosion condition of the battery pack.

[0041] Specifically, the method for testing corrosion resistance and weather resistance includes:

[0042] Step S100: Pre-processing time is achieved by using a test vehicle carrying the battery pack under test to travel at a specific speed under preset road conditions. This step S100 includes:

[0043] Step S101: Mount the battery pack to be tested onto the test vehicle according to the assembly requirements;

[0044] Step S110: Perform several road test pretreatment cycles, each pretreatment cycle including:

[0045] Step S111: Control the test vehicle to travel a first preset distance on a salt water road section at a first speed, wherein the salt water concentration of the salt water road section is 2-3%;

[0046] Step S112: Control the test vehicle to travel the second preset distance at the second speed on the dusty and gravel road section;

[0047] Step S113: Control the test vehicle to travel the third preset distance on the muddy road section at idle speed.

[0048] Step S200: Disassemble the battery pack to be tested, place it in an environmental chamber, adjust the environmental conditions of the environmental chamber, and store it for a preset period under different environmental chamber conditions; Step S200 includes:

[0049] Step S201: Remove the battery pack under test, which has been pre-treated in step S100, from the test vehicle and place its bottom surface into the environmental chamber at a first angle to the ground. When storing, install the interfaces of each high-voltage component according to the installation method to avoid leakage from the interface position.

[0050] Step S220: Execute several environmental condition cycles, the environmental condition cycles including:

[0051] Step S221: Adjust the environmental chamber conditions to standard climate conditions, and store the battery pack under test under these standard climate conditions for a first settling time. The standard climate conditions are 20-25°C and 50% humidity.

[0052] Step S222: Adjust the environmental chamber conditions to salt spray conditions, and store the battery pack under test under these salt spray conditions for a second settling time. The temperature in the salt spray conditions is 32-37°C and the salt concentration is 3%.

[0053] Step S223: Adjust the environmental chamber conditions to the first humid and hot condition, and store the battery pack under test under the first humid and hot condition for a third standing time. The temperature in the first humid and hot condition is 45-55°C and the humidity is 95%.

[0054] Step S224: Adjust the environmental chamber conditions to dry conditions, and store the battery pack under test under these dry conditions for a fourth settling time. The temperature under these dry conditions is 38-42°C and the humidity is 30%.

[0055] Step S225: Adjust the ambient temperature to the second humid heat condition, and store the battery pack under test under this second humid heat condition for a fifth standing time. The temperature in the second humid heat condition is 45-55°C and the humidity is 85%.

[0056] Step S300: Remove the battery pack under test from the environmental chamber, inspect its corrosion, and evaluate its corrosion resistance and weather resistance based on the corrosion condition; Step S300 includes:

[0057] Step S301: Remove the battery pack to be tested from the environmental chamber;

[0058] Step S311: Check whether the functions of each external interface are normal. If the interface functions are normal, proceed to step S320. If the external interface functions are not normal, you can directly proceed to step S320 to determine that the battery pack's corrosion resistance and weather resistance performance is unqualified.

[0059] Step S312: Detect whether there are macroscopic defects in the battery pack casing, including bubbles, pitting corrosion and perforation corrosion;

[0060] Step S313: Use electron microscopy and energy dispersive spectroscopy to detect whether there is micro-corrosion on the battery pack casing;

[0061] Step S314: Inject a preset pressure into the battery pack through the battery pack interface to check whether the airtightness of the battery pack is qualified;

[0062] Step S320: Generate a judgment result on whether the corrosion resistance and weather resistance performance of the battery pack is qualified based on the test results of steps S311 to S314.

[0063] In a preferred embodiment, the first speed is 15–25 km / h, and the first preset distance is 40–80 m; the second speed is 45–75 km / h, and the second preset distance is 8–12 km; the third preset distance is 15–25 m. Preferably, the first speed is 20 km / h, and the first preset distance is 50 m; the second speed is 60 km / h, and the second preset distance is 10 km; the third preset distance is 20 m.

[0064] In a preferred embodiment, in step S110, the vehicle is not washed after completing one road test pretreatment cycle. The road test is repeated once a day for 10 cycles to complete the road test pretreatment.

[0065] In a preferred embodiment, the specific implementation process of step S313 is as follows: The battery pack casing is analyzed using electron microscopy and energy dispersive spectroscopy (EDS). The chemical composition of the casing is analyzed using an EDS spectrometer to determine the chemical composition in the analyzed area. Electron microscopy and EDS analysis can assist in analyzing the causes of corrosion and determining the degree of wear and corrosion of the battery pack casing. The specific method is as follows:

[0066] 1) The battery pack casing sample was ultrasonically cleaned in anhydrous ethanol and acetone, respectively;

[0067] 2) Use a scanning electron microscope to observe the morphology of the cleaned sample under a low magnification field of view and identify the location of the characteristic areas of corrosion products.

[0068] 3) Following a macroscopic to microscopic approach, gradually magnify the observation magnification to observe the morphology of the characteristic areas of corrosion products. Observe their morphological characteristics (calculate the corrosion volume through corrosion area and corrosion depth), and combine with energy dispersive spectroscopy analysis to determine the chemical composition (Al2O3, Fe2O3·xH2O, etc.) of the characteristic points or surfaces to obtain the types and contents of corrosion product elements, and determine whether the degree of corrosion meets the standard (if the content of the preset type of corrosion product element exceeds 3%, or the corrosion area exceeds 0.0002m2, or the corrosion depth exceeds 0.5cm, or the corrosion volume exceeds 1cm3, then it exceeds the specified corrosion standard). If it does not exceed the corrosion standard, step S314 can be executed.

[0069] In a preferred embodiment, in step S314, a pressure of ±50 mbar is injected into the battery pack through the battery pack interface, and the leakage rate is considered acceptable if it is between -50 and 50 ml / min.

[0070] In a preferred embodiment, the environmental condition cycle in step S220 is no less than 20 times, and the preset period is no less than 20 days; more preferably, the environmental condition cycle is no less than 50 times, and the preset period is no less than 50 days; in a preferred embodiment, the time to complete one environmental condition cycle is set to 24 hours, and the preset period is set to 12 weeks (i.e., 84 cycles). The battery pack is stored continuously under the above conditions for 12 weeks. After 12 weeks, the battery pack is removed, and its sealing and corrosion resistance performance is evaluated. For example, in a preferred embodiment, the first settling time is set to 4 hours, the second settling time to 2 hours, the third settling time to 7 hours, the fourth settling time to 4 hours, and the fifth settling time to 7 hours. The environmental conditions and settling times in one environmental condition cycle are shown in the table below. The temperature and humidity conditions of the environmental chamber change in one cycle as follows: Figure 1 As shown:

[0071]

[0072]

[0073] In a preferred embodiment, the first included angle in step S201 is 5° to 15°. Preferably, the included angle is set to 10°. Placing the battery pack under test at this angle can maintain a thin water film on the surface, simulating the actual use condition, and avoid the influence of excessive water accumulation on the surface of the battery pack on the results.

[0074] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention; the dimensions described in the drawings and embodiments are not related to the specific physical object and are not used to limit the protection scope of the present invention. The physical dimensions can be selected and changed according to actual needs.

Claims

1. A method for detecting the corrosion and weather resistance of an automobile battery pack, characterized by, The method comprises the following steps: a test vehicle is used to carry the battery pack to be tested to drive under preset road conditions for a predetermined time for pretreatment, the battery pack to be tested is disassembled and placed in an environment chamber for a predetermined period of storage, and then the corrosion resistance of the battery pack to be tested is evaluated according to the corrosion condition of the battery pack to be tested. The method for detecting the corrosion resistance of an automobile battery pack comprises the following steps: Step S100: a test vehicle is used to carry the battery pack to be tested to drive under preset road conditions at a specific speed for a predetermined pretreatment time; Step S200: the battery pack to be tested is disassembled and placed in an environment chamber, the environment conditions of the environment chamber are adjusted, and the battery pack to be tested is stored in the environment chamber under different environment conditions for a predetermined period of time; Step S300: the battery pack to be tested is taken out of the environment chamber, the corrosion condition of the battery pack to be tested is detected, and the corrosion resistance of the battery pack to be tested is evaluated according to the corrosion condition; The step S100 comprises the following steps: Step S101: the battery pack to be tested is carried onto the test vehicle according to the assembly requirements; Step S110: a plurality of pretreatment cycles are performed, and each pretreatment cycle comprises the following steps: Step S111: the test vehicle is controlled to drive at a first speed on a salt water section for a first predetermined distance, and the salt water concentration of the salt water section is 2-3%; Step S112: the test vehicle is controlled to drive at a second speed on a dusty gravel section for a second predetermined distance; Step S113: the test vehicle is controlled to drive at an idle speed on a mud section for a third predetermined distance; The test vehicle is not cleaned after completing one road test pretreatment cycle in step S110; The step S200 comprises the following steps: Step S201: the battery pack to be tested pretreated in step S100 is disassembled from the test vehicle, and the bottom surface of the battery pack to be tested is placed in the environment chamber at a first included angle with the ground; Step S220: a plurality of environment condition cycles are performed, and the environment condition cycle comprises the following steps: Step S221: the environment chamber conditions are adjusted to standard climate conditions, the battery pack to be tested is stored under the standard climate conditions for a first standing time, the temperature in the standard climate conditions is 20-25 DEG C, and the humidity is 50%; Step S222: the environment chamber conditions are adjusted to salt spray conditions, the battery pack to be tested is stored under the salt spray conditions for a second standing time, the temperature in the salt spray conditions is 32-37 DEG C, and the salt concentration is 3%; Step S223: the environment chamber conditions are adjusted to first humid heat conditions, the battery pack to be tested is stored under the first humid heat conditions for a third standing time, the temperature in the first humid heat conditions is 45-55 DEG C, and the humidity is 95%; Step S224: the environment chamber conditions are adjusted to dry conditions, the battery pack to be tested is stored under the dry conditions for a fourth standing time, the temperature in the dry conditions is 38-42 DEG C, and the humidity is 30%; The first included angle in step S201 is 5-15 DEG.

2. The method for detecting corrosion and weather resistance of an automobile battery pack according to claim 1, characterized in that, The first speed is 15-25 km / h, the first predetermined distance is 40-80 m, the second speed is 45-75 km / h, the second predetermined distance is 8-12 km, and the third predetermined distance is 15-25 m.

3. The method for detecting corrosion and weather resistance of an automobile battery pack according to claim 2, characterized in that, The step S220 further comprises a step S225 of adjusting the temperature of the environment chamber to a second humid heat condition, and storing the measured battery pack in the second humid heat condition for a fifth standing time, wherein the temperature in the second humid heat condition is 45-55 DEG C, and the humidity is 85%.

4. The method for detecting corrosion and weather resistance of an automobile battery pack according to claim 3, characterized in that, The number of cycles of the environment condition in the step S220 is not less than 20, and the preset period is not less than 20 days.

5. The method for detecting the corrosion and weather resistance of an automobile battery pack according to any one of claims 1-4, characterized in that, The step S300 comprises: a step S301 of taking out the measured battery pack from the environment chamber; a step S311 of detecting whether the functions of the external interfaces are normal, and if the interface functions are normal, executing a step S320; a step S312 of detecting whether there is a macro defect in the battery pack shell, wherein the macro defect comprises a bubble, a pitting corrosion and a perforation corrosion; a step S313 of detecting whether there is a micro corrosion in the battery pack shell by using an electron microscope and an energy spectrum analysis; a step S314 of detecting whether the air tightness of the battery pack is qualified by hitting a preset pressure into the battery pack through the interface of the battery pack; a step S320 of generating a judgment result of whether the corrosion resistance and weather resistance of the battery pack are qualified according to the detection results of the steps S311-S314.

Images