Button cell ultrasonic in-situ detection device and detection method

Abstract

The invention relates to a button cell ultrasonic in-situ detection device and method, and the device comprises a button cell fixing device which is used for clamping and fixing a button cell to be detected, and enabling the surface of a positive electrode shell and / or a negative electrode shell of the button cell to have at least 90% of an unclamped exposed region and at most 10% of a clamped region; the button cell fixing equipment performs electric signal application and acquisition on the tested button cell through the clamped area; the ultrasonic detection system is used for carrying out ultrasonic in-situ detection on the button cell through the exposed area on the button cell; and the electrochemical detection system is connected with the button cell fixing equipment and is used for carrying out an electrochemical test on the button cell to be tested through the clamped area on the button cell.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to an ultrasonic in-situ detection device and a detection method for button batteries. Background Art

[0002] The rapid development of lithium batteries has promoted the widespread application of new energy in the fields of electricity, transportation, industry, and military. In recent years, long-range electric vehicles, electric aircraft, national security and other fields have put forward higher requirements for battery performance, and the development of high-energy-density and high-safety lithium batteries is the main direction of current research and development.

[0003] The internal structure of high-energy-density lithium batteries involves complex multiphase physical reactions and coupled dynamic evolution processes. Its research and development requires observation and research combined with advanced characterization techniques. At the same time, high-energy-density lithium batteries need to use effective in-situ characterization techniques to accurately analyze the failure process of the battery during service. At present, there are some technical means to characterize the evolution process inside the battery. In-situ differential electrochemical mass spectrometer (DEMS) can be used to study the gas production behavior during battery charging and discharging, and obtain gas information qualitatively and quantitatively. However, this technology lacks spatial information on the distribution of gas in the battery, and it is difficult to associate the battery structure with the reaction. X-ray imaging technology is widely used for solid phase characterization inside batteries, and is relatively mature in solid phase structure research. However, due to the low contrast between X-rays and gas / liquid phases, it is difficult to characterize the gas and liquid in the battery. In recent years, ultrasonic technology has gradually been applied to the field of battery research, and the use of ultrasound to non-destructively characterize batteries has received widespread attention and recognition in the industry.

[0004] The common method of ultrasonic transmission testing of batteries is to use a pair of ultrasonic probes placed on both sides of the battery to be tested, one as a sound wave transmitting probe and the other as a sound wave receiving probe. During the test, the ultrasonic wave is emitted from the transmitting probe on one side of the battery, passes through the inside of the battery, and is finally received by the receiving probe on the other side. At present, the ultrasonic non-destructive characterization technology of batteries is mainly divided into two categories: the first category is to use a fixed-position ultrasonic sensor probe to perform fixed-point detection on the battery, and use the change of the ultrasonic wave shape to evaluate the change of the internal state of the battery. The second category is to combine the ultrasonic probe with a mechanical scanning device to scan and image the battery to characterize the structural defects, side reaction gas production, electrolyte infiltration and other phenomena inside the battery. The current battery ultrasonic detection technology, whether it is fixed-point detection or scanning imaging, is only used for the detection of soft-pack batteries and hard-shell batteries.

[0005] At present, the above-mentioned ultrasonic detection technology and ultrasonic imaging technology cannot be applied to the detection of button batteries, especially in-situ detection during the charging and discharging process of button batteries. The main reasons are as follows:

[0006] First, in electrochemical testing, the charging and discharging fixture is fixed on both sides of the button battery casing. However, due to the small size of the button battery, the fixture will block most of the battery casing, especially the location of the pole piece. Since the ultrasonic wave needs to pass through the battery casing to propagate into the battery before the internal structure can be detected, and the existing charging and discharging test fixture blocks the pole piece area, it will block the propagation path of the ultrasonic wave, resulting in the inability to obtain a clear and reliable ultrasonic signal. Secondly, how to stably fix the button battery on the propagation path of the ultrasonic wave so that the ultrasonic signal can be detected stably and continuously is also a problem that cannot be solved by the existing technology, resulting in the inability to obtain a consistent and clear ultrasonic signal. In addition, in the ultrasonic scanning imaging mode, the existing button battery charging and discharging fixture and its auxiliary components will hinder the movement trajectory of the ultrasonic probe, and the scanning imaging of the entire area of ​​the button battery cannot be achieved, which further limits the application of ultrasonic detection technology in the field of button batteries.

[0007] In summary, the existing ultrasonic detection and imaging technologies cannot be effectively applied to the detection of button batteries due to fixture obstruction, signal instability and equipment structure limitations. Summary of the invention

[0008] In view of the defects existing in the prior art, the present invention provides a button battery ultrasonic in-situ detection device and detection method. Through the design of the button battery fixing device, the ultrasonic signal can penetrate the inside of the button battery, thereby obtaining an effective and clear ultrasonic detection signal. The ultrasonic detection system can realize the emission and collection of ultrasonic signals, and process the ultrasonic signals. At the same time, the electrochemical performance parameters of the battery during the charge and discharge cycle are detected in combination with the electrochemical detection system, and the correspondence between the ultrasonic signal and the battery electrochemical performance parameters and the internal state changes of the button battery during the charge and discharge cycle is characterized, so that the internal state of the battery can be effectively characterized in real time.

[0009] To achieve the above object, the present invention provides a button battery ultrasonic in-situ detection device, comprising:

[0010] A button battery fixing device, used for clamping and fixing the button battery to be tested, so that at least 90% of the surface of the positive electrode shell and / or the negative electrode shell of the button battery has an exposed area that is not clamped, and at most 10% of the clamped area; the button battery fixing device applies and collects electrical signals to the button battery to be tested through the clamped area;

[0011] An ultrasonic testing system, used for performing ultrasonic in-situ testing on the button battery through the exposed area on the button battery;

[0012] The electrochemical detection system is connected to the button battery fixing device and is used to perform an electrochemical test on the button battery through the clamped area on the button battery.

[0013] Preferably, at least 90% of the exposed area on the surface of the positive electrode shell of the button battery completely covers the area where the positive electrode plate of the button battery is located; and / or

[0014] At least 90% of the exposed area on the surface of the negative electrode shell of the button battery completely covers the area where the negative electrode plate of the button battery is located.

[0015] Preferably, the button battery fixing device comprises: an insulating plate, a positive contact component, a negative contact component, a positive electrical signal transmission line, and a negative electrical signal transmission line;

[0016] The insulating plate is provided with a button battery receiving hole, and the button battery is placed in the button battery receiving hole;

[0017] The positive contact component and the negative contact component are both made of conductive materials; wherein the positive contact component and / or the negative contact component have a hollow structure in the middle; the positive contact component and the negative contact component are respectively fixed on the first surface and the second surface of the insulating plate; and the positive contact component and the negative contact component respectively cover the areas on the positive electrode shell surface and the negative electrode shell surface of the button battery to form the clamped area; the hollow areas in the middle of the positive contact component and / or the negative contact component correspond to the exposed areas on the positive electrode shell surface and / or the negative electrode shell surface of the button battery respectively;

[0018] The positive electrode electrical signal transmission line is electrically connected to the surface of the positive electrode shell through the positive electrode contact component, and the negative electrode electrical signal transmission line is electrically connected to the surface of the negative electrode shell through the negative electrode contact component.

[0019] Further preferably, the first surface and the second surface of the insulating plate have two symmetrically arranged strip-shaped grooves; one end of the positive electrode electrical signal transmission line and the negative electrode electrical signal transmission line are respectively placed in the two strip-shaped grooves and fixed in the strip-shaped grooves by a transmission line fixing device;

[0020] The first surface and the second surface of the insulating plate each have at least two screw holes; the positive contact component and the negative contact component each have at least two through holes corresponding to the positions of the screw holes; each group of corresponding through holes and screw holes are fixed by bolts, so that the positive contact component is fixed on the first surface of the insulating plate, and the negative contact component is fixed on the second surface of the insulating plate.

[0021] Further preferably, among the screw holes, a screw hole on the first surface and a screw hole on the second surface are opened along the strip groove;

[0022] Among the bolts, the bolts used for fixing the screw holes opened along the strip-shaped grooves are metal bolts.

[0023] Preferably, the ultrasonic detection system comprises:

[0024] Control and analysis processing equipment, sending detection control instructions and drive equipment control signals for ultrasonic detection of button batteries, and receiving detection reception signals of ultrasonic detection and performing analysis and processing;

[0025] An ultrasonic detection device receives the detection control instruction and outputs a corresponding ultrasonic emission control signal according to the detection control instruction;

[0026] An ultrasonic transmitting probe receives the ultrasonic transmitting control signal and transmits a corresponding ultrasonic signal to an exposed area on the positive electrode shell side or the negative electrode shell side of the button battery;

[0027] An ultrasonic receiving probe and the ultrasonic transmitting probe are respectively arranged on the same side or both sides of the button battery, and collect the ultrasonic signal reflected or transmitted by the button battery to obtain a detection receiving signal, which is sent to the control and analysis processing device through the ultrasonic detection device;

[0028] The driving device receives the driving device control signal and performs driving control to generate relative displacement between the ultrasonic transmitting probe, the ultrasonic receiving probe and the button battery.

[0029] Further preferably, the button battery ultrasonic in-situ detection device further comprises a containing device; the containing device is filled with an insulating liquid for transmitting ultrasonic waves in the insulating liquid;

[0030] The accommodating device is provided with a button battery fixing platform, a transmitting probe mounting platform and a receiving probe mounting platform, the button battery fixing device is fixed on the button battery fixing platform, the ultrasonic transmitting probe is fixed on the transmitting probe mounting platform, and the ultrasonic receiving probe is fixed on the receiving probe mounting platform;

[0031] Under the driving control of the driving device, the ultrasonic transmitting probe on the transmitting probe mounting platform and the ultrasonic receiving probe on the receiving probe mounting platform synchronously generate relative motion with the button battery fixing platform.

[0032] Preferably, the electrochemical detection system comprises: an electrochemical tester and a data analysis device;

[0033] The electrochemical tester is connected to the button battery fixing device, applies a test signal to the button battery under test through the clamped area on the button battery, receives an electrochemical response signal, and sends the electrochemical response signal to the data analysis device for data analysis and processing.

[0034] In a second aspect, an embodiment of the present invention provides a button-type battery ultrasonic in-situ detection method of the button-type battery ultrasonic in-situ detection device according to the first aspect, the detection method comprising:

[0035] Clamping and fixing the button battery to be tested in a button battery fixing device, so that at least 90% of the surface of the positive electrode shell and / or the negative electrode shell of the button battery is exposed without being clamped, and at most 10% of the surface is clamped;

[0036] Using an ultrasonic testing system to perform ultrasonic in-situ testing on the button battery through the exposed area on the button battery;

[0037] An electrochemical testing system is used to perform an electrochemical test on the button battery through the clamped area on the button battery.

[0038] The button battery ultrasonic in-situ detection device provided by the embodiment of the present invention can realize ultrasonic in-situ detection of button batteries during the charging and discharging process, and simultaneously perform electrochemical performance testing, ultrasonic detection, and imaging. The device uses hollow conductive materials as a fixing fixture for the positive and / or negative electrodes of the button battery, and also serves as a charging and discharging electrode connector. The hollow design exposes at least 90% of the battery shell, especially the pole piece area is completely exposed, ensuring smooth transmission of ultrasonic signals, and solving the problem of existing fixtures blocking and hindering ultrasonic detection. The button battery ultrasonic in-situ detection device proposed by the present invention has a simple and stable structure, does not affect the ultrasonic detection effect or charging and discharging test results, and ensures the consistency of the tests of similar button batteries. When hollow conductive materials are used on one side of the positive and negative electrode shells, ultrasonic reflection detection can be performed; when hollow materials are used on both sides, ultrasonic waves can penetrate the battery, thereby obtaining clear transmission signals, and performing in-situ scanning imaging. Through the linkage analysis of ultrasonic signals and charging and discharging data, the present invention can non-destructively characterize the changes in the internal state of the battery in real time, and the extracted ultrasonic characteristic signals are highly correlated with the changes in battery voltage and current, which is helpful for battery research and development and failure analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a button battery ultrasonic in-situ detection device provided by an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the structure of a button battery fixing device provided in an embodiment of the present invention;

[0041] Figure 3 A top view of an insulating plate in a button-type battery fixing device provided by an embodiment of the present invention;

[0042] Figure 4 The voltage and current curves of the button battery in Example 1 of the present invention and the ultrasonic transmission images at different time states;

[0043] Figure 5a A comparison diagram of a curve drawn based on the ultrasonic flight time value corresponding to the ultrasonic transmission image of time variation after testing a button battery in Example 2 of the present invention and a battery voltage curve;

[0044] Figure 5b A comparison diagram of a curve drawn based on the maximum peak intensity value corresponding to the ultrasonic transmission image of time-varying after testing a button battery in Example 2 of the present invention and a battery voltage curve;

[0045] Figure 5c This is a comparison diagram of a curve drawn based on the area value of the ultrasonic low transmission region corresponding to the ultrasonic transmission image changing over time after testing the button battery in Example 2 of the present invention and the battery voltage curve. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0047] An embodiment of the present invention provides a button-type battery ultrasonic in-situ detection device for button-type battery ultrasonic in-situ detection.

[0048] First, let me introduce the in-situ ultrasonic detection of batteries, which refers to the simultaneous ultrasonic detection during the process of charging and discharging the battery and detecting its electrochemical performance. The parameters used to describe the electrochemical performance of the battery include but are not limited to voltage, current, capacity, energy, power, etc., and all electrochemical performance parameters known to those skilled in the art can be included.

[0049] The ultrasonic in-situ detection device for button-type batteries proposed by the present invention has the following structure: Figure 1 The system shown includes: a button battery fixing device 100, an ultrasonic detection system and an electrochemical detection system.

[0050] The button battery fixing device 100 is used to clamp and fix the button battery under test, so that there is at least 90% of the unclamped exposed area and at most 10% of the clamped area on the surface of the positive electrode shell and / or the negative electrode shell of the button battery; the button battery fixing device 100 applies and collects electrical signals to the button battery under test through the clamped area.

[0051] Specifically, at least 90% of the exposed area on the surface of the positive electrode shell of the button battery completely covers the area where the positive electrode plate of the button battery is located; and / or, at least 90% of the exposed area on the surface of the negative electrode shell of the button battery completely covers the area where the negative electrode plate of the button battery is located.

[0052] The ultrasonic testing system is used to perform ultrasonic in-situ testing of button batteries through the exposed area on the button batteries. The ultrasonic testing system includes:

[0053] The control and analysis processing device 200 sends a detection control instruction and a drive device control signal for ultrasonic detection of button batteries, and receives and analyzes the detection reception signal of the ultrasonic detection;

[0054] The ultrasonic detection device 300 receives the detection control instruction and outputs a corresponding ultrasonic emission control signal according to the detection control instruction.

[0055] The ultrasonic transmitting probe 400 receives the ultrasonic transmitting control signal and transmits a corresponding ultrasonic signal to the exposed area on the positive electrode shell side or the negative electrode shell side of the button battery.

[0056] The ultrasonic receiving probe 500 and the ultrasonic transmitting probe 400 are respectively arranged on the same side or both sides of the button battery, and collect the ultrasonic signal reflected or transmitted by the button battery to obtain the detection receiving signal, which is sent to the control and analysis processing device 200 through the ultrasonic detection device 300.

[0057] The driving device 600 receives the driving device control signal and performs driving control to generate relative displacement between the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 and the button battery. The driving control may specifically be to control the movement of the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 according to the driving device control signal to generate relative displacement between them and the button battery, and / or drive the movement of the button battery fixing device 100 to generate relative displacement between it and the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500. The driving device may specifically be a stepping motor, but is not limited thereto, and other electromechanical devices commonly used in the prior art may also be used, such as a mechanical gear transmission structure, etc. As long as the device can drive the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 to move, it is within the protection scope of the present invention.

[0058] The electrochemical detection system is connected to the button battery fixing device 100 and is used to perform electrochemical testing on the button battery through the clamped area on the button battery. The electrochemical detection system includes: an electrochemical tester 700 and a data analysis device 800.

[0059] The electrochemical tester 700 is connected to the button battery fixing device 100, applies a test signal to the button battery under test through the clamped area on the button battery, and receives an electrochemical response signal, and sends the electrochemical response signal to the data analysis device 800 for data analysis and processing. The electrochemical tester 700 can be specifically a charge and discharge tester, but is not limited thereto.

[0060] In addition, the button battery ultrasonic in-situ detection device further comprises a containing device 900. The containing device 900 is filled with insulating liquid for ultrasonic waves to be transmitted in the insulating liquid. The containing device 900 is preferably a silicone oil pool.

[0061] The accommodating device 900 is provided with a button battery fixing platform, a transmitting probe mounting platform and a receiving probe mounting platform. The button battery fixing device 100 is fixed on the button battery fixing platform, the ultrasonic transmitting probe 400 is fixed on the transmitting probe mounting platform, and the ultrasonic receiving probe 500 is fixed on the receiving probe mounting platform.

[0062] Under the driving control of the driving device 600 , the ultrasonic transmitting probe 400 on the transmitting probe mounting platform and the ultrasonic receiving probe 500 on the receiving probe mounting platform generate synchronous movement.

[0063] The ultrasonic detection device 300 may be specifically an ultrasonic transmission detection device, or may be an ultrasonic reflection detection device.

[0064] The ultrasonic transmission detection equipment realizes ultrasonic transmission imaging of button batteries. The ultrasonic transmitting probe 400 placed on one side of the button battery emits ultrasonic waves. After the ultrasonic waves propagate through the button battery, they are received by the ultrasonic receiving probe 500 placed on the other side of the button battery and sent to the control and analysis processing device 200 through the ultrasonic detection equipment 300 to analyze and process the ultrasonic signals and form images. Figure 1 Shown is the device structure of ultrasound transmission imaging.

[0065] The ultrasonic reflection detection equipment is used to perform ultrasonic reflection detection. Two ultrasonic probes are placed at a certain angle on the same side of the button battery for detection. The ultrasonic waves emitted by the ultrasonic transmitting probe propagate through the inside of the button battery and are reflected at the interface. The received ultrasonic reflection signals are analyzed and processed to form an image. For example, two ultrasonic probes are placed on the same side of the button battery at an angle of 45° relative to the plane of the positive or negative side of the button battery, and at an angle of 90° between the two ultrasonic probes, to detect the button battery.

[0066] Figure 2The structural diagram of the button battery fixing device provided in the embodiment of the present invention provides a specific structure of the button battery fixing device 100. It can be understood that this structure is a preferred specific solution that can implement the detection device and detection method of the present invention, and is not the only limited structure of the button battery fixing device.

[0067] Figure 3 A top view of an insulating plate in a button-type battery fixing device provided by an embodiment of the present invention. Figure 2 and Figure 3 Provide explanation.

[0068] like Figure 2 As shown, the button battery fixing device includes: an insulating plate 1, a positive electrode contact component 4, a negative electrode contact component 3, a positive electrode electrical signal transmission line 6, and a negative electrode electrical signal transmission line 5.

[0069] The insulating plate 1 is provided with a button battery receiving hole 21 (such as Figure 3 As shown), the button battery 2 is placed in the button battery receiving hole 21.

[0070] The positive electrode contact component 4 and the negative electrode contact component 3 are respectively made of a conductive material with a hollow middle portion; the positive electrode contact component 4 and the negative electrode contact component 3 are respectively fixed on the first surface and the second surface of the insulating plate 1; and the positive electrode contact component 4 and the negative electrode contact component 3 respectively cover the areas on the positive electrode shell surface and the negative electrode shell surface of the button battery 2 to form a clamped area; the hollow middle areas 41 and 31 of the positive electrode contact component 4 and the negative electrode contact component 3 respectively correspond to the exposed areas on the positive electrode shell surface and the negative electrode shell surface of the button battery 2; wherein the conductive material includes: copper and / or aluminum and / or stainless steel.

[0071] The positive electrode electrical signal transmission line 6 is electrically connected to the surface of the positive electrode shell through the positive electrode contact component 4, and the negative electrode electrical signal transmission line 5 is electrically connected to the surface of the negative electrode shell through the negative electrode contact component 3.

[0072] Furthermore, the first surface and the second surface of the insulating plate 1 have two symmetrically arranged strip grooves 19; one end of the positive electrode electric signal transmission line 6 and the negative electrode electric signal transmission line 5 are respectively placed in the two strip grooves 19, and fixed in the strip grooves by the transmission line fixing device 17. The positive electrode electric signal transmission line 6 and the negative electrode electric signal transmission line 5 can be more than one wire, respectively, for applying the electrochemical test signal and collecting the signal back to the electrochemical detection system.

[0073] The first surface and the second surface of the insulating plate 1 each have at least two screw holes; the positive contact component 4 and the negative contact component 3 each have at least two through holes corresponding to the positions of the screw holes; each set of corresponding through holes and screw holes is fixed by bolts, so that the positive contact component 4 is fixed on the first surface of the insulating plate 1, and the negative contact component 3 is fixed on the second surface of the insulating plate 1. In a specific example, Figure 2 As shown in , the edge of the negative contact component 3 is provided with a negative contact screw hole 10 and a negative fixing screw hole 14. In this example, the negative contact screw hole 10 and the negative fixing screw hole 14 extend to the insulating plate respectively, and the negative contact bolt 9 and the negative fixing bolt 13 respectively fix the negative contact component 3 and the insulating plate 1 together. The edge of the positive contact component 4 is provided with a positive contact screw hole 12 and a positive fixing screw hole 16. In this example, the positive contact screw hole 12 and the positive fixing screw hole 16 extend to the insulating plate respectively, and the positive contact bolt 11 and the positive fixing bolt 15 fix the positive contact component 4 and the insulating plate 1 together. Among them, the length of the negative contact bolt 9 is not enough to penetrate the negative contact screw hole 10, so as to avoid electrical contact with the positive electrical signal transmission line 6. Similarly, the length of the positive contact bolt 11 is not enough to penetrate the positive contact screw hole 12, so as to avoid electrical contact with the negative electrical signal transmission line 5.

[0074] In other implementations, the screw holes may not be through holes, as long as they can be used to fix the bolts.

[0075] Preferably, in the screw holes, a screw hole on the first surface and a screw hole on the second surface are opened along the strip groove 19; Figure 3 As shown, the positive electrode contact screw hole 12 and the negative electrode contact screw hole 10 are opened along the strip groove 19. It can be understood that Figure 2 and Figure 3The two strip-shaped grooves 19 and the position settings of the positive electrode contact screw hole 12 and the negative electrode contact screw hole 10 given in the specification are only examples of a specific implementation method. In actual implementation, the two strip-shaped grooves can also be arranged in a staggered parallel structure or arranged at a certain angle to each other. Among the bolts, the bolts used to fix the screw holes opened along the strip-shaped grooves 19 are contact bolts, which are made of metal materials, wherein the metal materials may include: copper and / or aluminum and / or stainless steel. Therefore, the negative electrode electrical signal transmission line 5 is respectively connected to the negative electrode contact component 3, the negative electrode contact bolt 9, and the negative electrode connection terminal 7 of the electrochemical tester, and the positive electrode electrical signal transmission line 6 is respectively connected to the positive electrode contact component 4, the positive electrode contact bolt 11, and the positive electrode connection terminal 8 of the electrochemical tester. In a specific implementation, the negative pole electric signal transmission line 5 and the positive pole electric signal transmission line 6 are conductive wires, wherein the contact end of the negative pole electric signal transmission line 5 and the negative pole contact component 3 is stripped of the insulating wire skin, and a good electrical contact with the negative pole contact component 3 is ensured under the tightening of the negative pole contact bolt 9, and the negative pole contact bolt 9 is wound at least half a circle, and the portion of the negative pole electric signal transmission line 5 extending beyond the insulating plate 1 is extended according to the actual test situation to ensure that there is no interference with the ultrasonic detection equipment; the positive pole electric signal transmission line 6 is also configured in the same way and will not be described in detail. Of course, the connection method of the negative pole electric signal transmission line 5 and the positive pole electric signal transmission line 6 to the charge and discharge test instrument is not limited to the implementation method of the insulating wire skin described above, and the connection method of clamping the wire clamp provided by the charge and discharge test instrument can also be used.

[0076] In addition to the contact bolts, the fixing bolts of the positive and negative electrodes can be realized by commonly used ordinary bolts, which can be made of metal or non-metallic materials, to achieve the fastening of the positive contact component 4, the negative contact component 3 and the insulating plate 1.

[0077] The fixing method between the positive contact component 4, the negative contact component 3 and the insulating plate 1 is not limited to the bolt fastening method used in the embodiment, and the clamping method of the positive contact component 4 and the negative contact component 3 to the button battery 2 is also not limited to the bolt fastening method in the embodiment.

[0078] Furthermore, the positive electrode contact component 4 and the negative electrode contact component 3 can be metal rings with ears made of metal materials, but are not limited thereto. They can also be square rings, irregular rings, or holes in metal sheets, as long as they can meet the requirements of not less than 90% of the area of ​​the corresponding positive and negative electrode shells being exposed and not more than 10% of the area being electrically connected and in contact, and their shapes are not limited. The shapes of the positive electrode contact component 4 and the negative electrode contact component 3 can be the same or different.

[0079] Preferably, the transmission line fixing device 17 can be specifically a wire pressing plate, which is implemented by an insulating sheet with a through hole. After the positive electric signal transmission line 6 or the negative electric signal transmission line 5 is placed in the strip groove 19 on the insulating plate 1, the wire pressing fixing bolt 18 is passed through the through hole on the transmission line fixing device 17 to fix the transmission line in the strip groove 19 to avoid displacement of the transmission line during the test and interference with the ultrasonic probe; the wire pressing plate fixing bolt 18 is a metal self-tapping bolt, and after the wire is placed in the strip groove on the insulating plate 1, the transmission line fixing device 17 can be fixed to the insulating plate 1. The above-mentioned method of fixing the transmission line is only a specific implementation structure, and other methods can also be used to limit the position of the transmission line to achieve the above purpose, including but not limited to printed circuit boards, wire ties, etc.

[0080] The button battery ultrasonic in-situ detection device of the present invention can perform ultrasonic in-situ detection of button batteries. A specific ultrasonic transmission detection process is used as an example to illustrate the specific detection device assembly and detection method as follows:

[0081] Step 1: Build the ultrasonic testing equipment.

[0082] Two ultrasonic probes with a certain center frequency are selected, one of which is used as an ultrasonic transmitting probe and the other as an ultrasonic receiving probe. The two probes are fixedly mounted on a platform driven by a stepper motor and can move freely up, down, left and right. The two probes are connected to an ultrasonic detection device with an integrated controller and an oscilloscope, respectively, for transmitting and collecting ultrasonic signals. The ultrasonic detection device and the stepper motor are both connected to a control and analysis processing device, which controls the transmission of ultrasonic signals and processes the collected signals, as well as controls the motion range and motion trajectory of the stepper motor.

[0083] Step 2: Fix the button battery.

[0084] Strip off the insulation of about 4 mm at both ends of the negative wire and the positive wire, put the negative wire and the positive wire into the strip groove of the insulating plate, cover the wires with a wire pressing plate, and fix the wire pressing plate to the insulating plate with a wire pressing fixing bolt to fix the negative wire and the positive wire; cover the positive contact component on the corresponding position of the insulating plate, pass the positive contact bolt through the corresponding opening on the positive contact component, and then wrap the metal wire with the insulation stripped at the contact end of the positive wire and the positive contact component around the positive contact bolt, tighten the positive contact bolt and the positive contact screw hole, pass the positive fixing bolt through the corresponding opening on the positive contact component, and then tighten the positive fixing bolt and the positive fixing screw hole.

[0085] Place the button battery in the button battery fixing device so that the positive side battery shell of the button battery maintains good physical contact with the positive contact component. Cover the negative contact component on the corresponding position of the insulating plate, pass the negative contact bolt through the corresponding opening on the negative contact component, wrap the metal wire with the insulation skin stripped off at the contact end of the negative lead and the negative contact component around the negative contact bolt, tighten the negative contact bolt with the positive contact screw hole, pass the negative fixing bolt through the corresponding opening on the negative contact component, and tighten the negative fixing bolt with the negative fixing screw hole, so that the negative side battery shell of the button battery maintains good physical contact with the negative contact component.

[0086] After the button cell is fixed, there are at least 90% of unclamped exposed areas and at most 10% of clamped areas on the surface of the positive electrode shell and / or the negative electrode shell of the button cell.

[0087] Step 3: Place the button battery holder in the receiving device and fix it in the middle position of a pair of ultrasonic probes.

[0088] Preferably, the button-type battery fixing device in the receiving device is fixed on both sides of the insulating plate 1 to prevent the button-type battery fixing device from moving.

[0089] Step 4: Connect the charge and discharge tester to the button battery and the data analysis equipment through the positive wire and the negative wire respectively, so as to adjust the battery charge and discharge parameters and collect the charge and discharge data.

[0090] Step 5: Immerse the two ultrasonic probes, the button battery fixing device and the button battery in an insulating liquid medium. The insulating liquid medium used in this example is silicone oil.

[0091] Step 6: Use ultrasonic scanning imaging detection method, drive two ultrasonic probes to move synchronously through stepper motor, and perform scanning transmission imaging on the button battery; use charge and discharge tester to perform charge and discharge cycle on the button battery, and collect electrochemical performance data during the charge and discharge process of the button battery.

[0092] The ultrasonic scanning imaging test and the charge-discharge cycle test may be performed simultaneously or at different times.

[0093] According to the test requirements, step 6 can be repeated multiple times, and the collected ultrasonic signals are continuously recorded by the control and analysis processing equipment, and the electrochemical performance parameters are continuously recorded by the data analysis equipment, such as real-time voltage, current, capacity, energy, power and other data during the charging and discharging process, until the electrochemical performance of the button battery such as the state of charge and / or the number of cycles meets the test requirements. In actual applications, the test requirements are set by the technicians in charge of the test according to the needs.

[0094] Step 7: Draw the ultrasonic transmission image of the button battery at different voltages by testing the ultrasonic signal data and the battery charge and discharge voltage data.

[0095] Step 8: Process the ultrasonic signal and extract the ultrasonic characteristic signal, and compare the extracted ultrasonic characteristic signal with the battery charge and discharge data to characterize the corresponding relationship between the ultrasonic signal and the internal state change of the battery during the charge and discharge cycle of the button battery.

[0096] Processing the ultrasonic signal and extracting the ultrasonic characteristic signal may include but is not limited to: converting the ultrasonic radio frequency wave signal into an envelope wave signal through high-pass filtering and Hilbert envelope; selecting the first peak in the envelope wave signal obtained at a certain point and extracting its corresponding flight time to define it as the ultrasonic flight time of the point; selecting the strongest peak in the envelope wave signal obtained at a certain point and extracting its corresponding sound wave intensity value to define it as the maximum peak intensity of the point; wherein, if the ultrasonic signal intensity obtained at a certain point is lower than the 20% threshold of the maximum intensity, the point is defined as an ultrasonic low transmission area. Through processing and feature extraction, characteristic signals such as ultrasonic flight time, maximum peak intensity, and ultrasonic low transmission area area can be obtained. Combining them with battery charge and discharge data can be used to characterize the correspondence between the ultrasonic signal of the button battery during the charge and discharge cycle and the change of the internal state of the battery.

[0097] In the above embodiment of the present invention, the change of the internal state of the button battery is characterized by ultrasonic transmission detection, that is, one probe is used as an ultrasonic transmitting probe, and the other probe is used as an ultrasonic receiving probe for signal collection. It can be understood that the button battery ultrasonic in-situ detection device of the present invention is also suitable for characterizing the change of the internal state of the button battery by ultrasonic reflection detection.

[0098] The embodiment of the present invention uses ultrasonic scanning imaging to detect button batteries. It can be understood that when no stepper motor is installed or the stepper motor is kept in a fixed position, the button battery ultrasonic in-situ detection device of the present invention is also suitable for ultrasonic in-situ detection of specific point positions of button batteries.

[0099] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0100] Example 1

[0101] The test battery sample in this embodiment is a button-type lithium-ion half-cell, the model specification of the battery shell is CR2032, the positive electrode material is a lithium-rich manganese-based oxide material, and the negative electrode material is a metal lithium foil.

[0102] The button battery ultrasonic in-situ detection device provided in this embodiment is as follows: Figure 1-Figure 3 As shown, the device assembly and testing methods are as described above.

[0103] The center frequency of the ultrasonic probe selected in this example is 2.5 MHz, and the distance between the two ultrasonic probes is 5 cm.

[0104] The electrochemical test is as follows: a fresh button lithium battery is charged to 4.8V at a rate of 0.05C through a charge and discharge tester, and then discharged to 2.0V at a rate of 0.05C. The charge and discharge current, battery voltage and other data are collected every 10s, and the corresponding relationship with time is recorded. At the same time, the ultrasonic signal is synchronously collected and recorded.

[0105] Ultrasonic testing uses ultrasonic scanning imaging detection method, and two ultrasonic probes are driven by stepper motors to move synchronously to scan and transmit button batteries. By controlling the moving speed of the stepper motor, the button battery scanning imaging is completed every ten minutes.

[0106] Based on the collected voltage and current data, a curve of the voltage and current changing with time during the charge and discharge process of the button battery is drawn.

[0107] Based on the collected ultrasonic signal data, ultrasonic transmission images of the button battery at different times during the charging and discharging process are drawn.

[0108] By matching the time points, the voltage curve of the button battery and the comparison of the changes in the ultrasonic transmission image at different voltages are obtained to characterize the evolution of the internal state during the battery charging and discharging process.

[0109] like Figure 4 As shown in the figure, a series of button battery ultrasound images obtained at different times and different voltages and the voltage and current curves of the button battery are shown. The color depth distribution in the ultrasound image represents the transmission intensity distribution of the ultrasound signal, which can intuitively reflect the uniformity difference inside the button battery. This difference distribution information inside the button battery is difficult to obtain directly through electrochemical testing or other non-destructive testing methods.

[0110] By comparing the ultrasonic images of button batteries under different voltages and currents, it can be found that during the charge and discharge process of button batteries, the ultrasonic low transmission area, i.e. the black signal area, expands as the voltage increases during the battery charging process, and then shrinks slightly as the voltage decreases during the battery discharge process. The ultrasonic low transmission area generally corresponds to the area where the electrolyte infiltration inside the battery is insufficient or where side reactions occur to produce gas. Figure 4 The changing trend of the ultrasonic image acquisition intuitively represents the evolution of the internal ultrasonic low transmission area of ​​the button battery during the charging and discharging process.

[0111] The button battery ultrasonic in-situ detection device in this embodiment can use ultrasound to perform non-destructive visual detection of button batteries without affecting the normal charging and discharging of the battery. The device and method of the present invention realize the ultrasonic transmission imaging of button batteries and the in-situ imaging of button batteries during charging and discharging for the first time, that is, a new button battery in-situ characterization imaging method is provided, and the spatial distribution information of the internal state of button batteries that is difficult to obtain by ordinary electrochemical testing is obtained.

[0112] Although the test battery in Example 1 of the present invention is a button-type lithium secondary battery, it is understandable that the button-type battery ultrasonic in-situ detection device of the present invention can also be used for all button-type batteries, including but not limited to button-type primary batteries and button-type secondary batteries assembled with various electrode materials. The size specifications of button batteries suitable for the button-type battery ultrasonic in-situ detection device are not limited to CR2032.

[0113] Example 2

[0114] The test battery sample in this embodiment is a button-type lithium battery, the model specification of the battery shell is CR2032, the positive electrode material is a lithium-rich manganese-based oxide material, and the negative electrode material is a metal lithium foil.

[0115] The button battery ultrasonic in-situ detection device provided in this embodiment is as follows: Figure 1-Figure 3 As shown, the device assembly and testing methods are as described above.

[0116] The center frequency of the ultrasonic probe selected in this example is 2.5 MHz, and the distance between the two ultrasonic probes is 5 cm.

[0117] The electrochemical test is as follows: a fresh button lithium battery is charged to 4.8V at a rate of 0.1C through a charge and discharge tester, and then discharged to 3V at a rate of 0.1C. The charge and discharge current, battery voltage and other data are collected every 10s, and the corresponding relationship with time is recorded.

[0118] The ultrasonic test uses ultrasonic scanning imaging detection method, and the stepper motor drives two ultrasonic probes to move synchronously to scan and transmit the button battery. By controlling the moving speed of the stepper motor, the button battery scanning imaging is completed every ten minutes. During this process, ultrasonic signals are continuously collected until the charging and discharging process of the button battery is completed, which lasts a total of 810 minutes.

[0119] Through the collected voltage data, a curve of battery voltage changing with time during the charge and discharge process of button batteries is drawn.

[0120] Through the collected ultrasonic signal data, ultrasonic transmission images of button batteries at different time states during the charging and discharging process were drawn, and a total of 81 ultrasonic transmission images of batteries at different time states were obtained.

[0121] A set of ultrasonic signals corresponding to each ultrasonic transmission image is processed by high-pass filtering and Hilbert envelope signal processing methods to extract three characteristic values ​​of ultrasonic flight time (TOF), ultrasonic maximum peak intensity (SA), and ultrasonic low transmission area (LA) in the ultrasonic signal. Among them, the threshold of the low transmission area is 20%, that is, the area where the ultrasonic transmission intensity is less than 20% of the maximum ultrasonic transmission intensity in the entire battery ultrasonic image.

[0122] As shown in Figure 5(a), the flight time values ​​corresponding to each of the above 81 battery ultrasonic transmission images are plotted as a curve corresponding to the battery charging and discharging time. By comparing it with the battery voltage curve, it can be seen that during the battery charging process, the flight time of the ultrasonic wave passing through the button battery initially increases slowly as the battery voltage increases; when the battery voltage reaches 4.6V, the flight time increases rapidly; after entering the discharge stage, the flight time shortens as the battery voltage decreases.

[0123] As shown in Figure 5(b), the maximum peak intensity values ​​corresponding to each of the above 81 battery ultrasonic transmission images are plotted as a curve corresponding to the battery charging and discharging time. Compared with the battery voltage curve, it can be seen that during the battery charging process, the maximum peak intensity of the ultrasonic wave in the button battery initially weakens as the battery voltage increases; when the battery voltage reaches 4.6V, the maximum peak intensity decays rapidly; after entering the discharge stage, the maximum peak intensity increases as the battery voltage decreases.

[0124] As shown in Figure 5(c), the area values ​​of the ultrasonic low transmission areas corresponding to each of the above 81 battery ultrasonic transmission images are plotted as a curve corresponding to the battery charging and discharging time. Compared with the battery voltage curve, it can be seen that during the battery charging process, the area of ​​the low transmission area in the battery ultrasonic transmission image initially expands as the battery voltage increases; when the battery voltage reaches 4.6V, the area of ​​the ultrasonic low transmission area increases rapidly; after entering the discharge stage, the area of ​​the ultrasonic low transmission area decreases as the battery voltage decreases.

[0125] The above results verify that the ultrasonic characteristic signal can effectively reflect the changes in the internal state of the button battery during the charging and discharging process. Among them, the drastic change of the ultrasonic signal when the battery is charged to above 4.6V is closely related to the gas production behavior of the lithium-rich manganese-based positive electrode material above 4.6V. When the voltage reaches above 4.6V, the lattice oxygen in the positive electrode material will participate in charge compensation, lose electrons and become activated, and then react with the electrolyte to produce gas.

[0126] Compared with solid electrode materials and electrolytes, the sound velocity of gas is lower and the acoustic impedance is greatly different. Therefore, the generation of gas will cause the flight time of the ultrasonic transmission signal to increase rapidly, the maximum peak intensity to decay rapidly, and the area of ​​the ultrasonic low transmission region to increase rapidly, which corresponds to the voltage curve in Figure 5. However, it is difficult to characterize the gas generation behavior inside the button battery with existing electrochemical tests and other non-destructive imaging methods. This embodiment uses a button battery ultrasonic in-situ detection device and combines ultrasonic data analysis to characterize and verify this phenomenon in-situ in button batteries for the first time.

[0127] Through the ultrasonic in-situ detection device and data analysis of the button-type battery in this embodiment, it is illustrated that the ultrasonic in-situ detection device and detection method of the button-type battery proposed in the present invention can be used to in-situ characterize the changes in the internal state of the button-type battery during the charging and discharging process, and form a good correspondence with the electrochemical curve, which confirms the effectiveness and accuracy of the device and method.

[0128] Those skilled in the art should further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0129] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0130] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A button battery ultrasonic in-situ detection device, characterized in that: The detection device comprises: A button battery fixing device, used for clamping and fixing the button battery to be tested, so that at least 90% of the surface of the positive electrode shell and / or the negative electrode shell of the button battery has an exposed area that is not clamped, and at most 10% of the clamped area; the button battery fixing device applies and collects electrical signals to the button battery to be tested through the clamped area; An ultrasonic testing system, used for performing ultrasonic in-situ testing on the button battery through the exposed area on the button battery; The electrochemical detection system is connected to the button battery fixing device and is used to perform an electrochemical test on the button battery through the clamped area on the button battery.

2. The ultrasonic in-situ detection device for button-type batteries according to claim 1, characterized in that: At least 90% of the exposed area on the surface of the positive electrode shell of the button battery completely covers the area where the positive electrode plate of the button battery is located; and / or At least 90% of the exposed area on the surface of the negative electrode shell of the button battery completely covers the area where the negative electrode plate of the button battery is located.

3. The button battery ultrasonic in-situ detection device according to claim 1, characterized in that: The button battery fixing device comprises: an insulating plate, a positive contact component, a negative contact component, a positive electrical signal transmission line, and a negative electrical signal transmission line; The insulating plate is provided with a button battery receiving hole, and the button battery is placed in the button battery receiving hole; The positive contact component and the negative contact component are both made of conductive materials; wherein the positive contact component and / or the negative contact component have a hollow structure in the middle; the positive contact component and the negative contact component are respectively fixed on the first surface and the second surface of the insulating plate; and the positive contact component and the negative contact component respectively cover the areas on the positive electrode shell surface and the negative electrode shell surface of the button battery to form the clamped area; the hollow areas in the middle of the positive contact component and / or the negative contact component correspond to the exposed areas on the positive electrode shell surface and / or the negative electrode shell surface of the button battery respectively; The positive electrode electrical signal transmission line is electrically connected to the surface of the positive electrode shell through the positive electrode contact component, and the negative electrode electrical signal transmission line is electrically connected to the surface of the negative electrode shell through the negative electrode contact component.

4. The button battery ultrasonic in-situ detection device according to claim 3, characterized in that: The first surface and the second surface of the insulating plate have two symmetrically arranged strip-shaped grooves; one end of the positive electrode electrical signal transmission line and the negative electrode electrical signal transmission line are respectively placed in the two strip-shaped grooves and fixed in the strip-shaped grooves by a transmission line fixing device; The first surface and the second surface of the insulating plate each have at least two screw holes; the positive contact component and the negative contact component each have at least two through holes corresponding to the positions of the screw holes; each group of corresponding through holes and screw holes are fixed by bolts, so that the positive contact component is fixed on the first surface of the insulating plate, and the negative contact component is fixed on the second surface of the insulating plate.

5. The button battery ultrasonic in-situ detection device according to claim 4, characterized in that: Among the screw holes, a screw hole on the first surface and a screw hole on the second surface are opened along the strip groove; Among the bolts, the bolts used for fixing the screw holes opened along the strip-shaped grooves are metal bolts.

6. The button battery ultrasonic in-situ detection device according to claim 1, characterized in that: The ultrasonic detection system comprises: Control and analysis processing equipment, sending detection control instructions and drive equipment control signals for ultrasonic detection of button batteries, and receiving detection reception signals of ultrasonic detection and performing analysis and processing; An ultrasonic detection device receives the detection control instruction and outputs a corresponding ultrasonic emission control signal according to the detection control instruction; An ultrasonic transmitting probe receives the ultrasonic transmitting control signal and transmits a corresponding ultrasonic signal to an exposed area on the positive electrode shell side or the negative electrode shell side of the button battery; An ultrasonic receiving probe and the ultrasonic transmitting probe are respectively arranged on the same side or both sides of the button battery, and collect the ultrasonic signal reflected or transmitted by the button battery to obtain a detection receiving signal, which is sent to the control and analysis processing device through the ultrasonic detection device; The driving device receives the driving device control signal and performs driving control to generate relative displacement between the ultrasonic transmitting probe, the ultrasonic receiving probe and the button battery.

7. The ultrasonic in-situ detection device for button-type batteries according to claim 6, characterized in that: The button battery ultrasonic in-situ detection device further comprises a containing device; the containing device is filled with an insulating liquid, and ultrasonic waves are transmitted in the insulating liquid; The accommodating device is provided with a button battery fixing platform, a transmitting probe mounting platform and a receiving probe mounting platform, the button battery fixing device is fixed on the button battery fixing platform, the ultrasonic transmitting probe is fixed on the transmitting probe mounting platform, and the ultrasonic receiving probe is fixed on the receiving probe mounting platform; Under the driving control of the driving device, the ultrasonic transmitting probe on the transmitting probe mounting platform and the ultrasonic receiving probe on the receiving probe mounting platform synchronously generate relative motion with the button battery fixing platform.

8. The button battery ultrasonic in-situ detection device according to claim 1, characterized in that: The electrochemical detection system includes: an electrochemical tester and a data analysis device; The electrochemical tester is connected to the button battery fixing device, applies a test signal to the button battery under test through the clamped area on the button battery, receives an electrochemical response signal, and sends the electrochemical response signal to the data analysis device for data analysis and processing.

9. A method for ultrasonic in-situ detection of button type batteries based on the ultrasonic in-situ detection device for button type batteries according to any one of claims 1 to 8, characterized in that: The detection method comprises: Clamping and fixing the button battery to be tested in a button battery fixing device, so that at least 90% of the surface of the positive electrode shell and / or the negative electrode shell of the button battery is exposed without being clamped, and at most 10% of the surface is clamped; Using an ultrasonic testing system to perform ultrasonic in-situ testing on the button battery through the exposed area on the button battery; An electrochemical testing system is used to perform an electrochemical test on the button battery through the clamped area on the button battery.

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