Device and method for dynamically detecting gas production rate of formation of soft package battery in situ

Abstract

The invention provides an in-situ dynamic detection soft package battery formation gas production rate device, which comprises a formation clamp, a supporting force monitoring device, a container tank, a liquid, a battery suspension device, a charging tester and a data processing system, and is characterized in that the data processing system is respectively connected with the supporting force monitoring device and the charging tester; the container tank is arranged on the supporting force monitoring device, liquid is arranged in the container tank, and the formation clamp is immersed in the liquid. According to the invention, the volume change in the battery formation process can be dynamically researched, the battery formation charging process and the volume change data are synchronously combined, and the method has important significance for the research of the battery formation process.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a device for in-situ dynamic detection of gas production of soft-pack batteries and a detection method using the device. Background Art

[0002] In the production process of soft-pack batteries, formation is an extremely critical process. During the formation and charging process, a series of complex chemical reactions occur in the battery, and a SEI film is generated on the surface of the negative electrode. Different gases will be produced at different time points. These gases have an important impact on battery performance. Therefore, detecting the gas production during the battery formation process, especially the in-situ dynamic detection of gas production during the formation process, is of great significance for the research and analysis of the formation mechanism.

[0003] At present, the gas production of soft-pack batteries can only be qualitatively judged through manual visual inspection, such as severe bulging, moderate bulging, and slight bulging. There is no special detection equipment that can quantitatively detect the gas production of the formation. The judgment varies with people's senses and there is no unified standard. CN104880232A provides a device and method for measuring the gas production of battery formation. The soft-pack battery is immersed in water, and the overflow water volume is collected by the drainage method to measure the gas production. Although this method can measure the gas production, its measurement accuracy by measuring the overflow volume is poor, and the response rate to slight volume changes is low. CN209623803U and CN220602633U improve the drainage device to improve the measurement accuracy of the drainage volume, thereby effectively improving the detection accuracy. However, its improved device is relatively complex, and the drainage volume measurement method cannot respond quickly to slight volume changes. CN212807220U provides a method for testing the gas production of a soft-pack battery, which directly places the formed soft-pack battery in a sealed vacuum container, tests the pressure change in the vacuum box, and detects the gas production during formation. Although this method can accurately detect a tiny amount of gas through a barometer, its device is complex and has strict requirements on the sealing of the vacuum box, and it is impossible to dynamically detect the change of the gas production of the battery over time during the formation process. Summary of the invention

[0004] In order to solve one of the technical problems existing in the background technology, the present invention improves the drainage method by ingenious design, converts the drainage volume measurement into the force measurement, greatly improves the measurement precision and accuracy of the battery formation gas production, and can directly measure the battery volume change in real time in situ, can quickly respond to the tiny volume change in the formation process, the measuring device is simple, can adapt to various test environments, and the test process operation method is simple and reliable. The present invention can actually measure the change of the battery volume during the formation and charging process, and synchronously test the change of the battery gas production rate during the formation.

[0005] To this end, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a device for in-situ dynamic detection of gas production during formation of a soft-pack battery, the device comprising: a formation fixture (2), a support force monitoring device (3), a container tank (4), a liquid (5), a battery suspension device (6), a charging tester (7) and a data processing system (8), wherein the data processing system (8) is connected to the support force monitoring device (3) and the charging tester (7), respectively, the container tank (4) is placed on the support force monitoring device (3), the container tank (4) is provided with a liquid (5), and the formation fixture (2) is immersed in the liquid (5).

[0007] In a specific embodiment of the present invention, the battery suspension device (6) is connected to the formation fixture (2) so that the formation fixture (2) is immersed in the liquid (5).

[0008] In a specific embodiment of the present invention, the battery suspension device (6) includes a suspension line, and the suspension line is a rigid filament that does not absorb liquid, so that the position of the formation fixture (2) does not move. In the present invention, during the gas production process of the battery core pack (1), the volume increases, and the upward buoyancy it is subjected to increases. The presence of the suspension line fixes the position of the battery core pack (1) to prevent it from floating on the liquid (5).

[0009] In a specific embodiment of the present invention, the formation fixture (2) is used to clamp the soft-pack battery (1) to be tested, and the positive and negative electrode tabs of the soft-pack battery (1) are respectively connected to a charging tester (7), and the charging tester (7) charges the soft-pack battery (1) to perform a formation process.

[0010] In a specific embodiment of the present invention, the data processing system (8) is used to collect the charging voltage of the charging tester (7) and the supporting force value monitored by the supporting force monitoring device (3), and convert the supporting force value through a calculation formula to output the gas production value.

[0011] In a specific embodiment of the present invention, the calculation formula is:

[0012] V 产气 =ΔF 支撑 / ρ 液 g, where V 产气 Indicates the gas production of soft-pack batteries, ΔF 支撑 represents the change in the supporting force value of the supporting force monitoring device (3) calculated by the data processing system (8), ρ 液 represents the density of liquid (5), g is the acceleration due to gravity, and g = 9.8 m / s 2 .

[0013] In a specific embodiment of the present invention, the liquid (5) is selected from water, silicone oil and kerosene.

[0014] In a specific embodiment of the present invention, the data processing system (8) can be connected to the supporting force monitoring device (3) and the charging tester (7) by electrical connection or signal connection.

[0015] In the device of the present invention, the chemical formation fixture (2) can be heated and adjusted according to the requirements of the chemical formation process.

[0016] On the other hand, the present invention provides a method for in-situ dynamic detection of gas production during formation of soft-pack batteries, wherein the detection method is performed by the device as described above.

[0017] In a specific embodiment of the present invention, the measuring method specifically comprises: placing the soft-pack battery (1) to be tested into a formation fixture (2), and connecting the positive and negative electrode tabs of the soft-pack battery (1) to a charging tester (7) respectively; starting the charging tester (7) to form the soft-pack battery (1) to be tested; and a data processing system (8) dynamically detecting the gas production during the formation of the soft-pack battery.

[0018] The basic principle of the present invention is that the soft-pack battery generates gas during the formation and charging process, which causes the air bag of the soft-pack battery to expand. The battery as a whole is suspended and immersed in the liquid. The battery volume increases and the buoyancy increases as a whole. According to Newton's third law, the container tank and the liquid therein as a whole will be subject to a downward reaction force, and the buoyancy is F. 浮 =ρ 液 V 排 The volume change of the battery as a whole when water is displaced is ΔV 排 That is the gas production of the battery as a whole, that is, ΔV 排 =V 产气 .

[0019] The stress analysis of the soft pack battery and the formation fixture as a whole is carried out:

[0020] Upward pulling force F of battery suspension device 拉 +Buoyancy F of the battery pack 浮 =The gravity of the soft pack battery and the formation fixture.

[0021] Perform stress analysis on the container tank and liquid as a whole:

[0022] The reaction force of buoyancy F 浮 + Weight of tank and liquid = Support force F of support force monitoring device 支撑 .

[0023] The gravity of all components will not change. Therefore, when the gas production volume of the soft pack battery increases, the buoyancy increases, and the reaction force of the buoyancy on the container tank and the liquid will also increase. The support force change of the support force monitoring device satisfies ΔF 支撑 =ρ 液 V 产气 ,Therefore, the gas production of the battery can be measured based on the force added by the support force monitoring device, that is, V 产气 =ΔF 支撑 / ρ 液 g.

[0024] Beneficial effects:

[0025] (1) The device of the present invention does not require other strict vacuum sealing equipment, and the equipment requirements are simple. The present invention converts the volume test caused by battery gas production into a support force test through ingenious design, avoiding the delay problem in the general drainage method for volume measurement, and converts the volume change of the battery into force test data in real time and dynamically.

[0026] (2) The use of a support force monitoring device greatly improves the accuracy and precision of the gas production test and can accurately measure tiny volume changes during the formation process.

[0027] (3) The present invention can dynamically study the volume change during the battery formation process and synchronously combine the battery formation and charging process with the volume change data, which is of great significance to the study of the battery formation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a device for in-situ dynamic detection of gas production of soft-pack batteries provided by the present invention;

[0029] Among them, 1-soft pack battery, 2-formation fixture, 3-gravity monitoring device, 4-container tank, 5-liquid, 6-battery hanging device, 7-charging tester, 8-data processing system;

[0030] Figure 2 This is a curve diagram showing synchronous changes in voltage and gas production volume during the formation and charging process of a soft-pack battery in Example 1 of the present invention;

[0031] Figure 3 This is a detection diagram of voltage change and gas production volume during the formation and charging process of the soft-pack battery in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0034] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0037] The present invention is further described in detail below through specific embodiments.

[0038] Example 1

[0039] like Figure 1As shown, this embodiment provides a device for in-situ dynamic detection of gas production during formation of a soft-pack battery, the device comprising: a formation fixture (2), a support force monitoring device (3), a container tank (4), a liquid (5), a battery suspension device (6), a charging tester (7) and a data processing system (8), wherein the data processing system (8) is connected to the support force monitoring device (3) and the charging tester (7), respectively, the container tank (4) is placed on the support force monitoring device (3), the container tank (4) is provided with a liquid (5), and the battery suspension device (6) is connected to the formation fixture (2) so that the formation fixture (2) is immersed in the liquid (5).

[0040] When the device of the present invention is used to dynamically detect the gas production of soft-pack batteries in situ, the following steps are included:

[0041] ① Preparation of soft-pack battery: Take a soft-pack battery (1) with air bag after filling and standing, clamp it with a formation fixture (2), expose the air bag, connect the positive and negative poles of the soft-pack battery (1) to the charging tester (7), and the charging tester (7) is connected to the data processing system (8). The soft-pack battery can be a lithium-ion soft-pack battery or a sodium-ion soft-pack battery.

[0042] ②Test system preparation: Take a container (4) of suitable size, fill it with half of liquid (5), place it in the support force monitoring device (3), and connect the support force monitoring device (3) to the data processing system (8). The liquid (5) is water, and the density of the liquid is ρ 液 .

[0043] ③ Assembling the test device: suspend the prepared soft-pack battery (1) and immerse it in the liquid (5), ensure that the air bag of the soft-pack battery (1) is immersed, the battery tabs are exposed, and there is no other contact between the soft-pack battery (1) and the container tank (4) except for the action of the liquid, and initialize and zero the support force monitoring device (3).

[0044] ④ Formation gas production test: Start the charging tester (7) to charge and form the soft pack battery (1), and the support force monitoring device (3) records the F in real time. 支撑 The data processing system (8) calculates the change ΔF of the data of the support force monitoring device (3) in real time. 支撑 The computer calculates the battery volume change and obtains the gas production V of the soft pack battery. 产气 =ΔF 支撑 / ρ 液 g. The data processing system (8) simultaneously records the charging voltage during the formation process in real time.

[0045] The voltage and gas production volume synchronous change curve obtained by the data processing system (8) in this embodiment is as follows: Figure 2As shown in the figure, it can be seen that the gas production rate in the second stage of the formation charging process is the largest, which is of great significance to the study of the battery formation process.

[0046] Comparative Example 1

[0047] This comparative example provides a conventional device for detecting the gas production of soft-pack batteries during formation, and the device comprises: a formation fixture, a measuring cylinder, a charging tester and a data processing system.

[0048] When using the device of this comparative example to in-situ detect the gas production of soft-pack battery formation, the following steps are included:

[0049] ① Preparation of soft-pack battery: Take the same soft-pack battery as in Example 1, immerse the battery in a measuring cylinder filled with liquid, and measure its initial volume V by drainage method. 1 , then remove the soft pack battery.

[0050] ② Formation charging test: The soft-pack battery is installed in the fixture, the positive and negative electrodes are connected to the charge and discharge tester respectively, the charging tester is started, and the soft-pack battery is charged by formation (the formation process is the same as that in Example 1), and the data processing system records the voltage change during the formation process in real time.

[0051] ③ Formation gas production test: After the formation test, remove the soft pack battery from the tester, remove the fixture, let the battery stand at room temperature and then immerse it in a measuring cylinder filled with liquid. Use the drainage method to measure its initial volume V 2 , calculate the volume change V of the battery during the formation process 产气 =V 2 -V 1 .

[0052] The battery voltage and gas production volume data obtained by the data processing system in this comparative example are as follows Figure 3 As shown in the figure, the volume change before and after formation charging can be obtained. Figure 2 and Figure 3 After the formation, the gas volume is 65cm 3 , indicating that the gas production detected by the device provided by the present invention is consistent with the traditional method, further verifying the detection accuracy of the device provided by the present invention.

[0053] The method for in-situ dynamic detection of gas production of soft-pack batteries provided by the present invention can synchronously detect gas production and formation voltage. Compared with the traditional method that can only know the volume difference before and after but cannot deeply analyze the gas production rate during the formation stage, the present invention can analyze which stage of the formation charging process is the most critical and has the largest gas production according to the gas production rate, and can be used to study and optimize the formation process.

[0054] The specific embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0055] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0056] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A device for in-situ dynamic detection of gas production of soft-pack batteries, characterized in that: The device comprises: a formation fixture (2), a supporting force monitoring device (3), a container tank (4), a liquid (5), a battery hanging device (6), a charging tester (7) and a data processing system (8), wherein the data processing system (8) is connected to the supporting force monitoring device (3) and the charging tester (7), respectively; the container tank (4) is placed on the supporting force monitoring device (3); the container tank (4) is provided with the liquid (5); and the formation fixture (2) is immersed in the liquid (5).

2. The device according to claim 1, characterized in that The battery suspension device (6) is connected to the formation fixture (2) so that the formation fixture (2) is immersed in the liquid (5).

3. The device according to claim 1, characterized in that The formation fixture (2) is used to clamp the soft-pack battery (1) to be tested. The positive and negative electrode tabs of the soft-pack battery (1) are respectively connected to a charging tester (7). The charging tester (7) charges the soft-pack battery (1) to perform a formation process.

4. The device according to claim 3, characterized in that The data processing system (8) is used to collect the charging voltage of the charging tester (7) and the supporting force value monitored by the supporting force monitoring device (3), and convert the supporting force value through a calculation formula to output a gas production value.

5. The device according to claim 4, characterized in that The calculation formula is: V 产气 =ΔF 支撑 / ρ 液 g, where V 产气 Indicates the gas production of soft-pack batteries, ΔF 支撑 represents the change in the supporting force value of the supporting force monitoring device (3) calculated by the data processing system (8), ρ 液 represents the density of the liquid (5), and g is the acceleration due to gravity.

6. The device according to claim 1, characterized in that The liquid (5) is selected from water, silicone oil and kerosene.

7. The device according to claim 1, characterized in that The battery suspension device (6) comprises a suspension line, and the suspension line is a rigid filament that does not absorb liquid, so that the position of the formation clamp (2) does not move.

8. A method for in-situ dynamic detection of gas production during formation of soft-pack batteries, characterized in that: The detection method is performed by a device as described in any one of claims 1 to 7; The measuring method comprises: placing a soft-pack battery (1) to be tested into a formation fixture (2), and connecting the positive and negative pole tabs of the soft-pack battery (1) to a charging tester (7) respectively; starting the charging tester (7) to form the soft-pack battery (1) to be tested; and a data processing system (8) dynamically detecting the gas production of the formation of the soft-pack battery.

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