Method and system for testing air tightness of battery pack

Abstract

Disclosed in the present invention are a method and system for testing the air tightness of a battery pack, the method comprising: step S1, by means of an upper-computer APP, setting air tightness test parameters comprising a target test air pressure and an allowable leakage rate; step S2, the upper-computer APP generating an inflation policy in light of an air inflow rate per unit time and the target test air pressure, and issuing same to a lower-computer program; step S3, the lower-computer program stepwise inflating a battery pack on the basis of the inflation policy until the battery pack reaches the target test air pressure, and displaying a real-time air pressure value; step S4, the lower-computer program stopping inflating the battery pack, and waiting until the air pressure of the battery pack is stable; step S5, the upper-computer APP acquiring from the lower-computer program the difference between an initial air pressure and a final air pressure during a leakage test time period, calculating a leakage rate per unit time and, on the basis of the allowable leakage rate set in step S1, determining whether the air tightness of the battery pack passes; and step S6, the lower-computer program controlling the battery pack to deflate. The present invention can improve the precision of testing the air tightness of batteries, helping to improve the production quality of the batteries.

Description

Battery pack air tightness detection method and system Technical Field

[0001] The present invention relates to a battery pack performance testing method, and in particular to a battery pack air tightness testing method and system. Background Art

[0002] With the development of electric vehicles and renewable energy, battery technology is becoming increasingly important. Battery airtightness is a key indicator of battery performance and is crucial for ensuring battery safety and stability. Therefore, battery airtightness testers have become indispensable equipment in battery production and quality control. Existing battery airtightness testers typically use methods such as pressure change and gas diffusion rate to test the airtightness inside the battery. In addition, some devices also use data acquisition and waveform analysis technologies to process and analyze the test results.

[0003] However, many existing battery air tightness testers still have some problems in actual use. For example, some devices may have problems such as insufficient sensitivity, inaccurate data processing, and insufficient adaptability to different types of batteries. In addition, some devices may misjudge or miss detections when processing complex waveforms, thereby affecting the accuracy and reliability of the test results. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a battery pack air tightness detection method and system that can improve the accuracy of battery air tightness detection and help improve the quality of battery production, in response to the shortcomings of the existing technology.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for detecting air tightness of a battery pack is implemented based on a lower computer program and an upper computer APP, and the method includes the following steps: step S1, a setting stage, in which air tightness detection parameters including a target test air pressure and a qualified leakage amount are set by the upper computer APP; step S2, a preparation stage, in which the upper computer APP combines the air intake volume per unit time and the target test air pressure to generate an inflation strategy and sends it to the lower computer program; step S3, an inflation stage, in which the lower computer program inflates the battery pack in a stepwise manner according to the inflation strategy until the battery pack reaches the target test air pressure, and displays the real-time air pressure value; step S4, a pressure stabilization stage, in which the lower computer program stops inflating the battery pack and waits for the battery pack air pressure to stabilize; step S5, a leakage detection stage, in which the upper computer APP obtains the starting air pressure and the ending air pressure difference within the leakage detection time period from the lower computer program, calculates the leakage amount per unit time, and judges whether the battery pack is air-tight according to the qualified leakage amount set in step S1; step S6, an exhaust stage, in which the lower computer program controls the exhaust of the battery pack.

[0007] Preferably, in step S2, the lower computer program controls the switch of the solenoid valve connected between the battery pack and the air source, thereby controlling the air intake per unit time.

[0008] Preferably, in step S3, the lower computer program uploads the air pressure data in the battery pack to the upper APP every preset time. After the upper APP collects a set of data containing n pressure values, it calculates the current air pressure value.

[0009] Preferably, in step S3, the lower computer program uploads the air pressure data in the battery pack to the upper APP every 40 ms.

[0010] Preferably, in step S3, a composite filtering algorithm is used to calculate the current air pressure value, and an inflation curve is drawn according to the real-time air pressure value set.

[0011] Preferably, in step S3, the composite filtering algorithm includes sorting the current set of data from low to high, taking n / 2 data values ​​in the middle position, and performing an average operation to obtain the current air pressure value.

[0012] Preferably, in step S4, the lower computer program closes the solenoid valve, and the upper APP displays the real-time air pressure value.

[0013] Preferably, in step S4, a data queue with a length of m is created, and the real-time air pressure value is saved in the data queue for standby use. The data queue adopts a first-in-first-out principle for data storage.

[0014] Preferably, in step S5, the calculation process of the leakage amount includes: defining the leakage detection time period as n seconds, the difference between the starting air pressure and the ending air pressure as a Pa, and the calculation formula of the leakage amount is: leakage amount = a*(60 / n).

[0015] A battery pack air tightness detection system includes a lower computer program and an upper computer APP, and the system is used to execute the battery pack air tightness detection method described above.

[0016] In the battery pack air tightness detection method disclosed in the present invention, based on steps S1 to S6, the present invention achieves the purpose of detecting leakage by detecting changes in the battery pack air pressure, and then judging the battery pack air tightness. In actual application, the system's own air pressure sensor is connected to the battery pack through an air pipe, and the air pressure sensor is used to obtain the air pressure in the battery pack in real time. When the detection is started, an external air pump inflates the battery pack through a specific port of the device. By controlling the proportional valve and the solenoid valve, when the battery pack reaches the specified air pressure set by the parameter, the inflation can be turned off in time. At this stage, the air tightness detection begins. After waiting for a period of time, the air pressure difference at the beginning and end of this period is compared to calculate the leakage per unit time, and then the battery pack air tightness is judged to be qualified based on the leakage. Compared with the existing technology, the present invention adopts a more reasonable algorithm for data processing and optimization, which not only greatly improves the accuracy of the measurement results, but also helps to improve the quality management of the battery, and better meets the application needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a flow chart of a battery pack air tightness detection method according to the present invention;

[0018] FIG2 is a schematic diagram of a data queue for storing real-time air pressure values. DETAILED DESCRIPTION

[0019] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

[0020] The present invention discloses a method for testing the air tightness of a battery pack. Referring to FIG1 , the method is implemented based on a lower computer program and an upper computer APP. The upper computer APP is an application installed on the upper computer, and the lower computer program is an application built into a testing instrument. The battery pack to be tested is connected to a preset air source via a pipeline having a proportional valve and a solenoid valve. The proportional valve serves as a safety protection and controls the upper limit of the air pressure. The solenoid valve is used to control the air intake switch and the air intake volume per unit time. Based on this, the method includes the following steps:

[0021] Step S1, setting stage, setting airtightness detection parameters including target test pressure and qualified leakage amount through the upper APP;

[0022] Step S2, preparation stage, the upper APP combines the air intake per unit time and the target test air pressure to generate an inflation strategy and sends it to the lower computer program;

[0023] Step S3, the inflation phase, the lower computer program inflates the battery pack step by step according to the inflation strategy until the battery pack reaches the target test pressure and displays the real-time pressure value;

[0024] Step S4, voltage stabilization stage, the lower computer program stops inflating the battery pack and waits for the battery pack pressure to stabilize;

[0025] Step S5, leakage detection phase, the upper APP obtains the difference between the starting and ending air pressures within the leakage detection period from the lower computer program, calculates the leakage volume per unit time, and determines whether the battery pack is airtight according to the qualified leakage volume set in step S1;

[0026] Step S6, the exhaust phase, the lower computer program controls the battery pack exhaust.

[0027] In the above method, based on steps S1 to S6, the present invention achieves the purpose of detecting leakage by detecting changes in the battery pack's air pressure, and then judging the battery pack's air tightness. In actual applications, the system's built-in air pressure sensor is connected to the battery pack through an air pipe, and the air pressure sensor is used to obtain the air pressure inside the battery pack in real time. When the test is started, an external air pump inflates the battery pack through a specific port of the device. By controlling the proportional valve and the solenoid valve, when the battery pack reaches the specified air pressure set by the parameter, the inflation can be turned off in time. At this stage, the air tightness test begins. After waiting for a period of time, the air pressure difference at the beginning and end of this period is compared to calculate the leakage per unit time, and then the air tightness of the battery pack is judged to be qualified based on the leakage. Compared with the existing technology, the present invention adopts a more reasonable algorithm for data processing and optimization, which not only greatly improves the accuracy of the measurement results, but also helps to improve the quality management of the battery, and better meets the application requirements.

[0028] Regarding the various detailed steps of the above method, in this embodiment:

[0029] For step S1, this embodiment sets corresponding airtightness detection parameters according to the standards of different battery packs, such as the test time of each stage, the test pressure required for inflation, the leakage qualification, etc., and the test is started only after the settings are made.

[0030] Furthermore, in step S2, the lower computer program controls the opening and closing of the solenoid valve connecting the battery pack and the air source, thereby controlling the air intake per unit time. Specifically, in step S2, the lower computer program pre-controls the opening and closing of the solenoid valve. Based on the air intake per unit time and the test pressure parameter, the inflation strategy for the next stage is generated. During this stage, the display value is not required, and the real-time value displayed on the upper app is reset to zero.

[0031] In step S3 of this embodiment, the lower computer program uploads the battery pack internal pressure data to the upper APP at preset intervals. After the upper APP collects a set of data containing n pressure values, it calculates the current pressure value. Simultaneously, in step S3, the lower computer program uploads the battery pack internal pressure data to the upper APP every 40ms. Furthermore, in step S3, a composite filtering algorithm is used to calculate the current pressure value, and an inflation curve is drawn based on the real-time pressure value set. The composite filtering algorithm includes sorting the current set of data from low to high, taking the n / 2 data values ​​in the middle position, and averaging them to obtain the current pressure value.

[0032] Specifically, in step S3, the lower-level computer program regularly controls the solenoid valve switch to inflate the air in a step-by-step manner until the test pressure is reached. During this stage, the current real-time air pressure value needs to be displayed. The lower-level computer program uploads real-time sensor data to the upper-level app every 40ms. After collecting a full set of n data, the upper-level app performs a composite filtering algorithm to calculate a real-time display of the current air pressure value. Based on the real-time point set, an inflation curve can be drawn. The algorithm implementation method includes: sorting the current set of data from low to high, intercepting the median value (i.e., taking the middle n / 2 values ​​to maximize the exclusion of data with excessive fluctuations), and then performing an algorithmic averaging on the remaining values ​​to obtain the final value.

[0033] In step S4, in this embodiment, the lower computer program closes the solenoid valve, discontinues inflation, and waits for the air pressure to stabilize. At this stage, the current real-time air pressure value is displayed. The data processing algorithm is the same as in step S3. A data queue of length m is created, and the real-time air pressure value is stored in the queue for future use. The queue operates on a first-in, first-out basis (see Figure 2).

[0034] It can be seen from the above principle that in the step S4 of this embodiment, the lower computer program closes the solenoid valve, and the upper APP displays the real-time air pressure value. At the same time, in the step S4, as shown in Figure 2, a group of data queues with a length of m is created, and the real-time air pressure value is saved in the data queue for standby use. The data queue adopts the first-in-first-out principle to save data.

[0035] Regarding step S5, this embodiment calculates the leakage volume per unit time based on the difference between the starting and ending air pressures within the detection period. This stage places higher demands on air pressure accuracy and stability, introducing a data queue. Based on the filtering algorithm, a recursive smoothing algorithm is then applied to obtain the final real-time value. The algorithm implementation involves first processing the collected data using the same algorithm as step S3 to obtain a temporary value, which is then added to the data queue created in step S4. The data in the queue is then processed using the algorithm of step S3 to obtain the final value.

[0036] The calculation process of leakage volume includes: the unit of leakage volume is Pascal per minute (Pa / min), the leakage detection time period is defined as n seconds, the difference between the starting air pressure and the ending air pressure is a Pa, and the calculation formula of leakage volume is: leakage volume = a*(60 / n).

[0037] In step 6 of this embodiment, the leakage volume per unit time is calculated based on the pressure difference obtained during the leakage detection phase. Combined with the qualified leakage volume set by the parameters, it is determined whether the battery pack is airtight. After the entire process is completed, exhaust begins.

[0038] On this basis, this embodiment also proposes a battery pack air tightness detection system, which is used to execute the battery pack air tightness detection method in the above embodiment. The system includes a lower computer program and an upper APP. Specifically, the lower computer program includes: MCU (microcontroller unit in embedded system) chip program, which is used to control the status of the proportional valve and the solenoid valve, and read the value of the air pressure sensor, and upload the data to the upper APP for processing. Among them, the role of the proportional valve is safety protection and control of the upper limit of air pressure. The solenoid valve serves as an air intake switch to control the air intake volume per unit time. In addition, the upper APP, as an application installed on the upper computer, can realize test logic control, data processing, interface display and user interaction, etc.

[0039] The above-mentioned algorithm provided by the present invention is based on the air pressure value obtained in real time by the air pressure sensor. During the various stages of starting the air tightness detection (preparation, inflation, pressure stabilization, leakage detection, exhaust), a relatively accurate real-time value is obtained through the composite operation of filtering, limiting, median, averaging and other algorithms and plotted into an air pressure waveform for intuitive display. At the same time, the present invention can effectively identify and filter out abnormal waveforms caused by interference or noise, thereby improving the accuracy and reliability of data processing. Based on the above characteristics, it can be seen that the method and system provided by the present invention have made outstanding progress in improving the air tightness performance of batteries, are particularly suitable for promotion and application in battery pack air tightness detection, and have good application prospects.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the technical scope of the present invention should be included in the scope of protection of the present invention.

Claims

1. A battery pack air tightness detection method, characterized in that: The method is implemented based on the lower computer program and the upper APP, and the method includes the following steps: Step S1, setting stage, setting airtightness detection parameters including target test pressure and qualified leakage amount through the upper APP; Step S2, preparation stage, the upper APP combines the air intake per unit time and the target test air pressure to generate an inflation strategy and sends it to the lower computer program; Step S3, the inflation phase, the lower computer program inflates the battery pack step by step according to the inflation strategy until the battery pack reaches the target test pressure and displays the real-time pressure value; Step S4, voltage stabilization stage, the lower computer program stops inflating the battery pack and waits for the battery pack pressure to stabilize; Step S5, leakage detection phase, the upper APP obtains the difference between the starting and ending air pressures within the leakage detection period from the lower computer program, calculates the leakage volume per unit time, and determines whether the battery pack is airtight according to the qualified leakage volume set in step S1; Step S6, the exhaust phase, the lower computer program controls the battery pack exhaust.

2. The battery pack air tightness detection method according to claim 1, wherein: In step S2, the lower computer program controls the switch of the solenoid valve connected between the battery pack and the air source, thereby controlling the air intake per unit time.

3. The battery pack air tightness detection method according to claim 1, wherein: In step S3, the lower computer program uploads the air pressure data in the battery pack to the upper APP every preset time. After the upper APP collects a set of data containing n pressure values, it calculates the current air pressure value.

4. The battery pack airtightness detection method according to claim 3, wherein: In step S3, the lower computer program uploads the air pressure data in the battery pack to the upper APP every 40 ms.

5. The battery pack air tightness detection method according to claim 3, wherein: In step S3, the current air pressure value is calculated using a composite filtering algorithm, and an inflation curve is drawn based on the real-time air pressure value set.

6. The battery pack air tightness detection method according to claim 5, wherein: In step S3, the composite filtering algorithm includes sorting the current set of data from low to high, taking n / 2 data values ​​in the middle position, and performing an average operation to obtain the current air pressure value.

7. The battery pack air tightness detection method according to claim 1, wherein: In step S4, the lower computer program closes the solenoid valve, and the upper APP displays the real-time air pressure value.

8. The battery pack airtightness detection method according to claim 7, wherein: In step S4, a data queue of length m is created, and the real-time air pressure value is saved in the data queue for standby use. The data queue adopts the first-in-first-out principle to save data.

9. The battery pack air tightness detection method according to claim 1, wherein: In step S5, the calculation process of the leakage amount includes: defining the leakage detection time period as n seconds, the difference between the starting air pressure and the ending air pressure as a Pa, and the calculation formula of the leakage amount is: leakage amount = a*(60 / n).

10. A battery pack air tightness detection system, characterized in that: The system includes a lower-level computer program and an upper-level APP, and the system is used to execute the battery pack air tightness detection method described in any one of claims 1-9.

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