An ultrasonic in-situ testing device and method for button batteries

Abstract

This invention relates to an ultrasonic in-situ testing device and method for coin cells. The testing device includes: a coin cell fixing device for clamping and fixing the coin cell under test, such that at least 90% of the surface of the positive electrode shell and / or negative electrode shell of the coin cell has an unclamped exposed area and at most 10% has a clamped area; the coin cell fixing device applies and acquires electrical signals to the coin cell under test through the clamped area; an ultrasonic testing system for performing ultrasonic in-situ testing of the coin cell through the exposed area; and an electrochemical testing system connected to the coin cell fixing device for performing electrochemical testing of the coin cell under test through the clamped area.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to an ultrasonic in-situ testing device and method for button batteries. Background Technology

[0002] The rapid development of lithium batteries has driven the widespread application of new energy in fields such as power, transportation, industry, and the military. In recent years, fields such as long-range electric vehicles, electric aircraft, and national security have placed higher demands on battery performance, making the development of high-energy-density and high-safety lithium batteries the main direction of current research and development.

[0003] High-energy-density lithium batteries involve complex multiphase reactions and coupled dynamic evolution processes, requiring advanced characterization techniques for observation and research. Simultaneously, during service, high-energy-density lithium batteries necessitate precise analysis of their failure processes using effective in-situ characterization techniques. Currently, several techniques exist for characterizing the internal evolution processes of batteries. In-situ differential electrochemical mass spectrometry (DEMS) can be used to study gas generation behavior during battery charging and discharging, providing qualitative and quantitative gas information; however, this technique lacks spatial information on gas distribution within the battery, making it difficult to correlate battery structure with reactions. X-ray imaging technology is widely used for solid-phase characterization within batteries and is relatively mature in solid-phase structure research; however, due to the low contrast of X-rays with the gas / liquid phase, it is difficult to characterize gases and liquids within the battery. In recent years, ultrasonic technology has been increasingly applied to battery research, utilizing ultrasound for non-destructive characterization of batteries, gaining widespread attention and recognition within the industry.

[0004] The common method for ultrasonic transmission testing of batteries involves placing a pair of ultrasonic probes on either side of the battery under test, one acting as the transmitting probe and the other as the receiving probe. During testing, ultrasonic waves are emitted from the transmitting probe on one side of the battery, pass through the battery's interior, and are finally received by the receiving probe on the other side. Currently, ultrasonic non-destructive characterization techniques for batteries are mainly divided into two categories: the first uses a fixed-position ultrasonic sensor probe to perform point-to-point testing on the battery, utilizing changes in the ultrasonic wave shape to assess changes in the battery's internal state. The second combines ultrasonic probes with mechanical scanning devices to perform scanning imaging of the battery, characterizing internal structural defects, side reaction gas generation, electrolyte wetting, and other phenomena. Current ultrasonic testing technologies for batteries, whether point-to-point testing or scanning imaging, are only applied to the testing of pouch cells and hard-case cells.

[0005] Currently, the aforementioned ultrasonic testing and imaging technologies cannot be applied to the testing of coin cells, especially for in-situ testing during the charging and discharging process. The main reasons are as follows:

[0006] First, in electrochemical testing, charge-discharge fixtures are fixed to both sides of the coin cell casing. However, due to the small size of coin cells, the fixtures obscure a large area of ​​the casing, especially the electrode area. Since ultrasonic waves need to penetrate the casing to reach the battery's interior for internal structural testing, the existing charge-discharge fixtures, by obstructing the electrode area, block the propagation path of the ultrasonic waves, resulting in the inability to obtain clear and reliable ultrasonic signals. Second, how to stably fix the coin cell in the ultrasonic wave propagation path to ensure a stable and continuous ultrasonic signal is also a problem that current technology cannot solve, leading to inconsistent and unclear ultrasonic signals. Furthermore, in ultrasonic scanning imaging mode, existing coin cell charge-discharge fixtures and their auxiliary components obstruct the movement trajectory of the ultrasonic probe, preventing scanning and imaging of the entire coin cell area, which further limits the application of ultrasonic testing technology in the coin cell field.

[0007] In summary, existing ultrasonic testing and imaging technologies cannot be effectively applied to the testing of button cells due to limitations such as fixture obstruction, signal instability, and equipment structure. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides an ultrasonic in-situ testing device and method for button cells. Through the design of the button cell fixing device, ultrasonic signals can penetrate the interior of the button cell, thereby obtaining effective and clear ultrasonic detection signals. The ultrasonic detection system can transmit and acquire ultrasonic signals, process them, and simultaneously combine them with an electrochemical detection system to detect electrochemical performance parameters during the battery's charge-discharge cycle. This characterizes the correspondence between the ultrasonic signals, battery electrochemical performance parameters, and internal state changes during the charge-discharge cycle, enabling real-time and effective characterization of the battery's internal state.

[0009] To achieve the above objectives, the present invention provides an ultrasonic in-situ testing device for button cells, comprising:

[0010] A button cell fixing device is used to clamp and fix a button cell under test, such that at least 90% of the surface of the positive and / or negative electrode shell of the button cell is exposed and at most 10% is clamped; the button cell fixing device applies and collects electrical signals to the button cell under test through the clamped area.

[0011] An ultrasonic testing system is used to perform in-situ ultrasonic testing on the coin cell through the exposed area on the coin cell.

[0012] An electrochemical detection system, connected to the button cell fixing device, is used to perform electrochemical testing on the button cell under test through the clamped area on the button cell.

[0013] Preferably, at least 90% of the exposed area on the surface of the positive electrode casing of the coin cell completely covers the area where the positive electrode sheet of the coin cell is located; and / or

[0014] At least 90% of the exposed area on the surface of the negative electrode casing of the coin cell completely covers the area where the negative electrode sheet of the coin cell is located.

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

[0016] The insulating plate has a button cell receiving hole, and the button cell is placed in the button cell receiving hole;

[0017] Both the positive electrode contact component and the negative electrode contact component are made of conductive material; wherein the positive electrode contact component and / or the negative electrode contact component has a hollow structure in the middle; the positive electrode contact component and the negative electrode contact component are respectively fixed to the first surface and the second surface of the insulating plate; and the areas of the positive electrode contact component and the negative electrode contact component covering the positive electrode shell surface and the negative electrode shell surface of the coin cell respectively form the clamping area; the hollow areas in the middle of the positive electrode contact component and / or the negative electrode contact component correspond to the exposed areas of the positive electrode shell surface and / or the negative electrode shell surface of the coin cell 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] More preferably, the first and second surfaces of the insulating plate have two symmetrically arranged strip-shaped grooves; one end of the positive electrical signal transmission line and the negative electrical signal transmission line are respectively placed in the two strip-shaped grooves and fixed in the strip-shaped grooves by the transmission line fixing device;

[0020] The first and second surfaces of the insulating plate each have at least two screw holes; the positive and negative contact components 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 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] More preferably, in the screw hole, a screw hole on a first surface and a screw hole on a second surface are formed along the strip groove;

[0022] Of the bolts, the bolts used to fix the threaded holes opened along the strip groove are metal bolts.

[0023] Preferably, the ultrasonic testing system includes:

[0024] The control and analysis processing equipment sends detection control commands and drive equipment control signals for ultrasonic testing of button cells, and receives and analyzes ultrasonic testing signals.

[0025] An ultrasonic testing device receives the testing control command and outputs a corresponding ultrasonic emission control signal according to the testing control command.

[0026] An ultrasonic transmitting probe receives the ultrasonic transmitting control signal and sends a corresponding ultrasonic signal to the exposed area of ​​the positive or negative electrode shell side of the button cell.

[0027] An ultrasonic receiving probe, which is disposed on the same side or both sides of the button cell battery, and the ultrasonic transmitting probe are respectively disposed on the same side or both sides of the button cell battery. The ultrasonic signals reflected or transmitted by the button cell battery are collected to obtain a detection and receiving signal, which is then sent to the control and analysis processing equipment through the ultrasonic detection equipment.

[0028] The driving device receives the control signal from the driving device and executes driving control to cause relative displacement between the ultrasonic transmitting probe and the ultrasonic receiving probe and the button cell battery.

[0029] More preferably, the button cell ultrasonic in-situ testing device further includes a containing device; the containing device is filled with an insulating liquid for transmitting ultrasonic waves in the insulating liquid;

[0030] The containing device includes 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 drive control of the drive 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 includes: an electrochemical testing instrument and a data analysis device;

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

[0034] In a second aspect, embodiments of the present invention provide a method for ultrasonic in-situ testing of a button cell battery using the ultrasonic in-situ testing device described in the first aspect above, the testing method comprising:

[0035] The button cell to be tested is clamped and fixed in a button cell fixing device, such that at least 90% of the surface of the positive and / or negative electrode shells of the button cell is exposed and at most 10% is clamped.

[0036] The button cell is subjected to in-situ ultrasonic testing using an ultrasonic testing system through the exposed area on the button cell.

[0037] An electrochemical testing system is used to perform electrochemical tests on the coin cell under test through the clamped area on the coin cell.

[0038] The ultrasonic in-situ testing device for coin cells provided in this invention enables in-situ ultrasonic testing of coin cells during charging and discharging, while simultaneously performing electrochemical performance testing, ultrasonic detection, and imaging. The device uses a perforated conductive material as a fixing clamp for the positive and / or negative electrodes of the coin cell, which also serves as a charging and discharging electrode connector. The perforated design exposes at least 90% of the battery casing, especially the electrode area, ensuring smooth ultrasonic signal transmission and solving the problem of existing clamps obstructing ultrasonic testing. The ultrasonic in-situ testing device for coin cells proposed in this invention has a simple and stable structure, does not affect the ultrasonic testing effect or charge / discharge test results, and ensures consistency in testing similar coin cells. When a perforated conductive material is used on one side of the positive and negative electrode casing, ultrasonic reflection testing can be performed; when perforated 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 charge / discharge data, this invention can non-destructively characterize changes in the internal state of the battery in real time. The extracted ultrasonic feature signals are highly correlated with changes in battery voltage and current, which is helpful for battery research and development and failure analysis. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the composition structure of the ultrasonic in-situ testing device for button batteries provided in an embodiment of the present invention;

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

[0041] Figure 3 This is a top view of the insulating plate in the button cell fixing device provided in an embodiment of the present invention;

[0042] Figure 4 The figures show the voltage and current curves of the button cell in Embodiment 1 of the present invention, as well as ultrasonic transmission images at different time states.

[0043] Figure 5a This is a comparison chart of the ultrasonic flight time value corresponding to the ultrasonic transmission image based on time variation after testing a button cell in Embodiment 2 of the present invention and the battery voltage curve.

[0044] Figure 5b This is a comparison chart of the maximum peak intensity value of the ultrasonic transmission image based on time variation after testing a button cell in Embodiment 2 of the present invention and the battery voltage curve.

[0045] Figure 5c This is a comparison chart of the curve plotted on the area value of the low-transmission region corresponding to the time-varying ultrasonic transmission image after testing a button cell in Embodiment 2 of the present invention and the battery voltage curve. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] This invention provides an ultrasonic in-situ testing device for button batteries, used for ultrasonic in-situ testing of button batteries.

[0048] First, we will introduce in-situ ultrasonic testing of batteries, which refers to performing ultrasonic testing simultaneously during the charging and discharging process of a battery to test its electrochemical performance. Parameters used to describe the battery's electrochemical performance include, but are not limited to, voltage, current, capacity, energy, and power; electrochemical performance parameters known to those skilled in the art can also be included.

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

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

[0051] Specifically, at least 90% of the exposed area of ​​the positive electrode casing of the coin cell completely covers the area where the positive electrode plate of the coin cell is located; and / or, at least 90% of the exposed area of ​​the negative electrode casing of the coin cell completely covers the area where the negative electrode plate of the coin cell is located.

[0052] An ultrasonic testing system is used for in-situ ultrasonic testing of coin cells through exposed areas. The ultrasonic testing system includes:

[0053] The control and analysis processing device 200 sends detection control commands and drive device control signals for ultrasonic testing of button cells, and receives and analyzes ultrasonic testing reception signals.

[0054] The ultrasonic testing equipment 300 receives testing control commands and outputs corresponding ultrasonic transmission control signals according to the testing control commands.

[0055] The ultrasonic transmitting probe 400 receives ultrasonic transmission control signals and sends corresponding ultrasonic signals to the exposed areas of the positive or negative electrode shell side of the button cell.

[0056] The ultrasonic receiving probe 500 and the ultrasonic transmitting probe 400 are respectively set on the same side or both sides of the button cell battery. The ultrasonic signals reflected or transmitted by the button cell battery are collected to obtain the detection and receiving signals, which are then sent to the control and analysis processing equipment 200 through the ultrasonic detection equipment 300.

[0057] The driving device 600 receives a driving device control signal and executes driving control to create relative displacement between the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 and the button cell battery. Specifically, the driving control may involve controlling the movement of the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 according to the driving device control signal to create relative displacement between them and the button cell battery, and / or driving the movement of the button cell battery fixing device 100 to create relative displacement between it and the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500. The driving device may be a stepper motor, but is not limited to this; other commonly used electromechanical devices in the prior art, such as mechanical gear transmission structures, may also be used. Any device capable of driving the ultrasonic transmitting probe 400 and the ultrasonic receiving probe 500 to move is within the scope of protection of this invention.

[0058] An electrochemical detection system, connected to a coin cell fixing device 100, is used to perform electrochemical tests on the coin cell under test through the clamped area on the coin cell. The electrochemical detection system includes an electrochemical tester 700 and a data analysis device 800.

[0059] The electrochemical tester 700 is connected to the coin cell fixing device 100. It applies a test signal to the coin cell under test through the clamping area on the coin cell and receives the electrochemical response signal, which is then sent to the data analysis device 800 for data analysis and processing. The electrochemical tester 700 may be specifically a charge-discharge tester, but is not limited to this.

[0060] In addition, the button cell ultrasonic in-situ testing device also includes a receiving device 900; the receiving device 900 is filled with an insulating liquid for transmitting ultrasonic waves. The receiving device 900 is preferably a silicone oil bath.

[0061] The housing device 900 includes 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 drive control of the aforementioned drive 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 move synchronously.

[0063] The aforementioned ultrasonic testing equipment 300 can be specifically an ultrasonic transmission testing equipment or an ultrasonic reflection testing equipment.

[0064] The ultrasonic transmission testing equipment realizes ultrasonic transmission imaging of button cells. Ultrasonic waves are emitted by an ultrasonic transmitting probe 400 placed on one side of the button cell. After the ultrasonic waves propagate through the button cell, they are received by an ultrasonic receiving probe 500 placed on the other side of the button cell. The ultrasonic waves are then sent to the control and analysis processing equipment 200 through the ultrasonic testing equipment 300 for ultrasonic signal analysis and processing to form an image. Figure 1 The diagram shows the structure of an ultrasound transmission imaging device.

[0065] Ultrasonic reflection testing equipment is used for ultrasonic reflection testing. Two ultrasonic probes are placed at a certain angle on the same side of the coin cell for testing. The ultrasonic waves emitted by the ultrasonic transmitting probe propagate through the inside of the coin cell 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 coin cell at a 45° angle relative to the plane of the positive or negative electrode side of the coin cell, and at a 90° angle between the two ultrasonic probes, to test the coin cell.

[0066] Figure 2This is a schematic diagram of the structure of a button cell battery fixing device provided in an embodiment of the present invention, showing a specific structure of a button cell battery fixing device 100. It should be understood that this structure is a preferred embodiment of the detection device and detection method of the present invention, and is not the only limited structure for a button cell battery fixing device.

[0067] Figure 3 This is a top view of the insulating plate in the button cell battery fixing device provided in an embodiment of the present invention. (In conjunction with...) Figure 2 and Figure 3 Please provide an explanation.

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

[0069] The insulating plate 1 has a button cell battery receiving hole 21 (e.g., Figure 3 As shown, the button cell 2 is placed in the button cell receiving hole 21.

[0070] The positive electrode contact 4 and the negative electrode contact 3 are made of conductive material with a hollow center. The positive electrode contact 4 and the negative electrode contact 3 are fixed to the first surface and the second surface of the insulating plate 1, respectively. The positive electrode contact 4 and the negative electrode contact 3 cover the positive electrode shell surface and the negative electrode shell surface of the button cell 2, respectively, forming a clamping area. The hollow center areas 41 and 31 of the positive electrode contact 4 and the negative electrode contact 3 correspond to the exposed areas of the positive electrode shell surface and the negative electrode shell surface of the button cell 2, respectively. The conductive material includes copper and / or aluminum and / or stainless steel.

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

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

[0073] The first and second surfaces of the insulating board 1 each have at least two screw holes; the positive electrode contact 4 and the negative electrode contact 3 each have at least two through holes corresponding to the screw hole positions; each set of corresponding through holes and screw holes is fixed by bolts, so that the positive electrode contact 4 is fixed to the first surface of the insulating board 1, and the negative electrode contact 3 is fixed to the second surface of the insulating board 1. In a specific example, such as Figure 2 As shown, the negative contact component 3 has a negative contact screw hole 10 and a negative fixing screw hole 14 on its edge. In this example, the negative contact screw hole 10 and the negative fixing screw hole 14 extend to the insulating plate, respectively. The negative contact bolt 9 and the negative fixing bolt 13 fix the negative contact component 3 to the insulating plate 1, respectively. The positive contact component 4 has a positive contact screw hole 12 and a positive fixing screw hole 16 on its edge. In this example, the positive contact screw hole 12 and the positive fixing screw hole 16 extend to the insulating plate, respectively. The positive contact bolt 11 and the positive fixing bolt 15 fix the positive contact component 4 to the insulating plate 1, respectively. The length of the negative contact bolt 9 is insufficient to penetrate the negative contact screw hole 10 to avoid electrical contact with the positive electrical signal transmission line 6. Similarly, the length of the positive contact bolt 11 is insufficient to penetrate the positive contact screw hole 12 to avoid electrical contact with the negative electrical signal transmission line 5.

[0074] In other implementation schemes, the aforementioned screw holes do not need to be through holes, as long as they can be used to fix the bolts.

[0075] Preferably, in the screw hole, a screw hole on a first surface and a screw hole on a second surface are formed along the groove 19; as shown Figure 3 As shown, the positive electrode contact screw hole 12 and the negative electrode contact screw hole 10 are formed along the strip groove 19. It can be understood that... Figure 2 and Figure 3The positions of the two strip grooves 19 and the positive and negative contact screw holes 12 and 10 shown are only examples of one specific implementation. In actual implementation, the two strip grooves can also be arranged in a staggered parallel structure or at a certain angle to each other. Among the bolts, the bolts used to fix the screw holes along the strip grooves 19 are contact bolts, made of metal, which may include copper and / or aluminum and / or stainless steel. Therefore, the negative electrical signal transmission line 5 is connected to the negative contact component 3, the negative contact bolt 9, and the negative connection terminal 7 of the electrochemical tester, respectively, and the positive electrical signal transmission line 6 is connected to the positive contact component 4, the positive contact bolt 11, and the positive connection terminal 8 of the electrochemical tester, respectively. In practice, the negative signal transmission line 5 and the positive signal transmission line 6 are wires. The insulation of the negative signal transmission line 5 is removed from the contact end with the negative contact component 3. With the negative contact bolt 9 tightened, good electrical contact with the negative contact component 3 is ensured, and the negative contact bolt 9 is wound at least half a turn. The portion of the negative signal transmission line 5 extending beyond the insulation plate 1 is extended as needed to ensure no interference with the ultrasonic testing equipment. The positive signal transmission line 6 is configured similarly and will not be elaborated further. Of course, the connection method between the negative signal transmission line 5 and the positive signal transmission line 6 and the charge / discharge testing instrument is not limited to the insulation method described above; the clamping method provided with the charge / discharge testing instrument can also be used.

[0076] Apart from the contact bolts, the fixing bolts for the positive and negative poles can be made of common ordinary bolts, either metal or non-metal, to secure the positive contact component 4, the negative contact component 3, and the insulating plate 1.

[0077] The fixing method between the positive electrode contact component 4, the negative electrode 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 electrode contact component 4 and the negative electrode contact component 3 for the button cell 2 is 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 lugs made of metallic material, but are not limited to this. They can also be square rings, irregular rings, or obtained by opening holes in a metal sheet, as long as they can satisfy the requirement that no less than 90% of the area of ​​the corresponding positive and negative electrode shells is exposed and no more than 10% of the area is for electrical connection contact. Their shapes are not limited. The positive electrode contact component 4 and the negative electrode contact component 3 can have the same shape or different shapes.

[0079] Preferably, the aforementioned transmission line fixing device 17 can be specifically a wire clamping plate, implemented by an insulating sheet with through holes. After the positive electrical signal transmission line 6 or the negative electrical signal transmission line 5 is placed into the slot 19 on the insulating plate 1, the wire clamping fixing bolt 18 passes through the through hole on the transmission line fixing device 17 to fix the transmission line in the slot 19, preventing displacement of the transmission line during testing and interference with the ultrasonic probe. The wire clamping fixing bolt 18 is a metal self-tapping bolt, which can be used to fix the transmission line fixing device 17 to the insulating plate 1 after the wire is placed into the slot on the insulating plate 1. The above-described method of fixing the transmission line is only one specific implementation structure. Other methods can also be used to restrict the position of the transmission line to achieve the above purpose, including but not limited to printed circuit boards, wire ties, etc.

[0080] The ultrasonic in-situ testing device for button batteries of the present invention is capable of performing ultrasonic in-situ testing of button batteries. The following description uses a specific ultrasonic transmission testing process as an example. The specific assembly of the testing device and the testing method are as follows:

[0081] Step 1: Set up the ultrasonic testing equipment.

[0082] Two ultrasonic probes with a specific center frequency are selected, one as the ultrasonic transmitter and the other as the ultrasonic receiver. The two probes are fixedly mounted on a platform driven by a stepper motor that can move freely up, down, left, and right. The two probes are connected to an ultrasonic testing device equipped with an integrated controller and an oscilloscope, respectively for transmitting and acquiring ultrasonic signals. Both the ultrasonic testing device and the stepper motor are connected to a control and analysis processing device, which controls the transmission of ultrasonic signals, processes the acquired signals, and controls the movement range and trajectory of the stepper motor.

[0083] Step 2: Secure the button battery.

[0084] Strip approximately 4mm of insulation from both ends of the negative and positive wires. Place the negative and positive wires into the slots of the insulating board, cover the wires with a wire clamp, and fix the clamp to the insulating board with wire clamping bolts to secure the negative and positive wires. Place the positive contact component on the corresponding position on the insulating board. After passing the positive contact bolt through the corresponding hole on the positive contact component, wrap the stripped metal wire at the contact end of the positive wire and the positive contact component around the positive contact bolt. Tighten the positive contact bolt to the positive contact screw hole. After passing the positive fixing bolt through the corresponding hole on the positive contact component, tighten the positive fixing bolt to the positive fixing screw hole.

[0085] Place the button cell battery in the button cell battery holder, ensuring good physical contact between the positive terminal side of the battery casing and the positive terminal contact component. Place the negative terminal contact component on the corresponding position on the insulating board. Pass the negative terminal contact bolt through the corresponding opening on the negative terminal contact component. Wrap the stripped metal wire (with the insulation removed) around the negative terminal contact bolt. Tighten the negative terminal contact bolt to the positive terminal contact screw hole. Pass the negative terminal fixing bolt through the corresponding opening on the negative terminal contact component and tighten it to the negative terminal fixing screw hole, ensuring good physical contact between the negative terminal side of the button cell battery casing and the negative terminal contact component.

[0086] After the button cell is secured, at least 90% of the surface of the positive and / or negative electrode casings of the button cell is exposed and at most 10% is clamped.

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

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

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

[0090] Step 5: Immerse the two ultrasonic probes, the button cell securing device, and the button cell in an insulating liquid medium. In this example, silicone oil is used as the insulating liquid medium.

[0091] Step 6: Using ultrasonic scanning imaging detection method, two ultrasonic probes are moved synchronously by a stepper motor to perform scanning transmission imaging on the coin cell battery; the coin cell battery is charged and discharged in cycles using a charge and discharge tester to collect electrochemical performance data during the charging and discharging process.

[0092] Ultrasonic scanning imaging and charge-discharge cycle testing can be performed simultaneously or at different times.

[0093] Depending on the testing requirements, step 6 can be repeated multiple times. The acquired ultrasonic signals are continuously recorded using control and analysis equipment, and electrochemical performance parameters, such as real-time voltage, current, capacity, energy, and power during charging and discharging, are continuously recorded using data analysis equipment until the coin cell's state of charge and / or cycle count, and other electrochemical performance characteristics, meet the testing requirements. In practical applications, the testing requirements are set by those skilled in the art who perform the testing.

[0094] Step 7: Using the ultrasonic signal data and battery charge / discharge voltage data obtained from the test, plot ultrasonic transmission images of the coin cell at different voltages.

[0095] Step 8: Process the ultrasonic signal and extract the ultrasonic feature signal, and compare the extracted ultrasonic feature signal with the battery charge and discharge data to characterize the correspondence between the ultrasonic signal and the internal state changes of the coin cell during the charge and discharge cycle.

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

[0097] In the above embodiments of the present invention, the changes in the internal state of the coin cell are characterized by ultrasonic transmission detection, i.e., one probe acts as an ultrasonic transmitting probe, and the other probe acts as an ultrasonic receiving probe to collect signals. It is understood that the coin cell ultrasonic in-situ detection device of the present invention is also applicable to characterizing changes in the internal state of the coin cell using ultrasonic reflection detection.

[0098] The embodiments of the present invention use ultrasonic scanning imaging to detect button cells. It can be understood that, even without a stepper motor or when the stepper motor is kept in a fixed position, the ultrasonic in-situ detection device for button cells of the present invention is also applicable to ultrasonic in-situ detection of specific points on button cells.

[0099] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0100] Example 1

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

[0102] The coin cell ultrasonic in-situ testing device provided in this embodiment is as follows: Figures 1-3 As shown, the equipment assembly and testing methods are as described above.

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

[0104] Electrochemical testing was conducted as follows: Fresh coin-type lithium batteries were charged to 4.8V at a rate of 0.05C using a charge-discharge tester, and then discharged to 2.0V at a rate of 0.05C. Charge / discharge current, battery voltage, and other data were collected every 10 seconds, and the correlation with time was recorded. Ultrasonic signals were also simultaneously acquired and recorded.

[0105] The ultrasonic testing employs an ultrasonic scanning imaging method. Two ultrasonic probes are moved synchronously by a stepper motor to perform scanning transmission imaging of the button cell. By controlling the movement speed of the stepper motor, a button cell scanning image is completed every ten minutes.

[0106] Based on the collected voltage and current data, plot the voltage and current variation curves over time during the charging and discharging process of the coin cell battery.

[0107] Based on the collected ultrasonic signal data, ultrasonic transmission images of the coin cell at different times during the charging and discharging process were plotted.

[0108] By matching time points, the voltage curve of the coin cell and the changes in ultrasonic transmission images at different voltages are obtained, which characterizes the evolution of the internal state of the battery during charging and discharging.

[0109] like Figure 4 As shown in the figure, a series of ultrasonic images of coin cells obtained at different times and voltages, along with the voltage-current curves of the coin cells, are presented. The color distribution in the ultrasonic images represents the transmission intensity distribution of the ultrasonic signal, which can intuitively reflect the uniformity differences within the coin cell. This information on the internal distribution differences of the coin cell is difficult to obtain directly through electrochemical testing or other non-destructive testing methods.

[0110] By comparing ultrasonic images of coin cells under different voltages and currents, it can be observed that during the charging and discharging process of coin cells, the ultrasonic low-transmission region, i.e., the black signal region, expands as the voltage increases during charging, and then slightly shrinks as the voltage decreases during discharging. The ultrasonic low-transmission region generally corresponds to areas where the electrolyte wetting inside the battery is insufficient or where side reactions and gas generation occur. Figure 4 The changing trends acquired by ultrasound images intuitively characterize the evolution of the low-transmission ultrasound region inside the coin cell during charging and discharging.

[0111] The coin cell ultrasonic in-situ testing device in this embodiment can perform non-destructive visual testing of coin cells using ultrasound without affecting the normal charging and discharging of the battery. The device and method of this invention achieve, for the first time, ultrasonic transmission imaging and in-situ imaging during the charging and discharging process of coin cells, providing a novel in-situ characterization and imaging method for coin cells, and obtaining spatial distribution information of the internal state of coin cells that is difficult to obtain through ordinary electrochemical testing.

[0112] Although the test battery in Embodiment 1 of this invention is a coin cell lithium secondary battery, it is understood that the ultrasonic in-situ testing device for coin cells of this invention can also be used for all coin cells, including but not limited to coin cell primary batteries and coin cell secondary batteries assembled with various electrode materials. The size specifications of the coin cells suitable for this ultrasonic in-situ testing device are not limited to CR2032.

[0113] Example 2

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

[0115] The coin cell ultrasonic in-situ testing device provided in this embodiment is as follows: Figures 1-3 As shown, the equipment assembly and testing methods are as described above.

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

[0117] The electrochemical test was conducted by charging a fresh coin cell lithium battery to 4.8V at a rate of 0.1C using a charge-discharge tester, and then discharging it to 3V at a rate of 0.1C. Data such as charge / discharge current and battery voltage were collected every 10 seconds, and the correlation between these data and time was recorded.

[0118] The ultrasonic testing employed an ultrasonic scanning imaging method. Two ultrasonic probes, driven by a stepper motor, moved synchronously to perform scanning transmission imaging of the coin cell battery. By controlling the stepper motor's movement speed, a coin cell battery scan was completed every ten minutes. Ultrasonic signals were continuously acquired throughout this process until the coin cell battery's charging and discharging process ended, lasting a total of 810 minutes.

[0119] By collecting voltage data, a curve showing the change of battery voltage over time during the charging and discharging process of a coin cell battery is plotted.

[0120] By collecting ultrasonic signal data, ultrasonic transmission images of the coin cell at different time states during the charging and discharging process were drawn, resulting in a total of 81 ultrasonic transmission images of the battery at different time states.

[0121] The ultrasonic signals corresponding to each ultrasonic transmission image were processed using high-pass filtering and Hilbert envelope signal processing methods to extract three feature values: time of flight (TOF), maximum peak intensity (SA), and area of ​​low transmission region (LA). The threshold for the low transmission region was 20%, meaning the area where the ultrasonic transmission intensity was 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 81 ultrasonic transmission images of the battery 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 waves passing through the button cell 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 81 ultrasonic transmission images of the battery are plotted as a curve corresponding to the battery charging and discharging time. By comparing 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 cell initially decreases 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 corresponding low-transmission regions in the 81 ultrasonic transmission images of the battery are plotted as a curve corresponding to the battery charging and discharging time. By comparing with the battery voltage curve, it can be seen that during the battery charging process, the area of ​​the low-transmission region in the ultrasonic transmission image of the battery initially expands as the battery voltage increases; when the battery voltage reaches 4.6V, the area of ​​the low-transmission region increases rapidly; after entering the discharging stage, the area of ​​the low-transmission region decreases as the battery voltage decreases.

[0125] The above results verify that ultrasonic characteristic signals can effectively reflect the changes in the internal state of coin cells during charging and discharging. Specifically, the drastic changes in the ultrasonic signal that occur when the battery is charged to above 4.6V are closely related to the gas generation behavior of the lithium-rich manganese-based cathode material above 4.6V. When the voltage reaches above 4.6V, lattice oxygen in the cathode material participates in charge compensation, loses electrons and becomes activated, and then reacts with the electrolyte to produce gas.

[0126] Compared to solid electrode materials and electrolytes, gases have lower sound velocity and significantly different acoustic impedances. Therefore, gas generation leads to a rapid increase in the flight time of the ultrasonic transmission signal, a rapid decrease in the maximum peak intensity, and a rapid increase in the area of ​​the low-transmission region, corresponding to the voltage curve in Figure 5. Existing electrochemical testing and other non-destructive imaging methods struggle to characterize the gas generation behavior inside coin cells. This embodiment, through a coin cell ultrasonic in-situ detection device combined with ultrasonic data analysis, is the first to characterize and verify this phenomenon in coin cells in situ.

[0127] Through the ultrasonic in-situ detection device and data analysis of the coin cell battery in this embodiment, it is shown that the ultrasonic in-situ detection device and detection method of the coin cell battery proposed in this invention can be used to characterize the changes in the internal state of the coin cell battery during the charging and discharging process in situ, 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 will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0129] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented in hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0130] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment 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 within the scope of protection of the present invention.

Claims

1. A button cell ultrasonic in-situ testing device, characterized in that, The detection device includes: A button cell fixing device is used to clamp and fix a button cell under test, such that at least 90% of the surface of the positive and / or negative electrode shells of the button cell is exposed and at most 10% is clamped; the exposed area completely covers the area where the electrode is located, and a perforated conductive material is used as a fixing clamp for the positive and / or negative electrodes of the button cell, which also serves as a charge / discharge electrode connector; the button cell fixing device applies and collects electrical signals to the button cell under test through the clamped area. An ultrasonic testing system is used to perform in-situ ultrasonic testing of the coin cell in an insulating liquid medium through the exposed area on the coin cell. An electrochemical detection system, connected to the button cell fixing device, is used to perform electrochemical testing on the button cell under test through the clamped area on the button cell.

2. The ultrasonic in-situ testing device for button batteries according to claim 1, characterized in that, At least 90% of the exposed area on the surface of the positive electrode casing of the coin cell completely covers the area where the positive electrode sheet of the coin cell is located; and / or At least 90% of the exposed area on the surface of the negative electrode casing of the coin cell completely covers the area where the negative electrode sheet of the coin cell is located.

3. The ultrasonic in-situ testing device for button batteries according to claim 1, characterized in that, The button cell fixing device includes: an insulating plate, a positive electrode contact component, a negative electrode contact component, a positive electrode electrical signal transmission line, and a negative electrode electrical signal transmission line; The insulating plate has a button cell receiving hole, and the button cell is placed in the button cell receiving hole; Both the positive electrode contact component and the negative electrode contact component are made of conductive material; wherein the positive electrode contact component and / or the negative electrode contact component has a hollow structure in the middle; the positive electrode contact component and the negative electrode contact component are respectively fixed to the first surface and the second surface of the insulating plate; and the areas of the positive electrode contact component and the negative electrode contact component covering the positive electrode shell surface and the negative electrode shell surface of the coin cell respectively form the clamping area; the hollow areas in the middle of the positive electrode contact component and / or the negative electrode contact component correspond to the exposed areas of the positive electrode shell surface and / or the negative electrode shell surface of the coin cell 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 ultrasonic in-situ testing device for button batteries according to claim 3, characterized in that, The first and second surfaces of the insulating plate have two symmetrically arranged strip-shaped grooves; one end of the positive electrical signal transmission line and the negative electrical signal transmission line are respectively placed in the two strip-shaped grooves and fixed in the strip-shaped grooves by the transmission line fixing device; The first and second surfaces of the insulating plate each have at least two screw holes; the positive and negative contact components 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 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 ultrasonic in-situ testing device for button batteries according to claim 4, characterized in that, In the screw hole, a screw hole on a first surface and a screw hole on a second surface are formed along the strip groove; Of the bolts, the bolts used to fix the threaded holes opened along the strip groove are metal bolts.

6. The ultrasonic in-situ testing device for button batteries according to claim 1, characterized in that, The ultrasonic testing system includes: The control and analysis processing equipment sends detection control commands and drive equipment control signals for ultrasonic testing of button cells, and receives and analyzes ultrasonic testing signals. An ultrasonic testing device receives the testing control command and outputs a corresponding ultrasonic emission control signal according to the testing control command. An ultrasonic transmitting probe receives the ultrasonic transmitting control signal and sends a corresponding ultrasonic signal to the exposed area of ​​the positive or negative electrode shell side of the button cell. An ultrasonic receiving probe, which is disposed on the same side or both sides of the button cell battery, and the ultrasonic transmitting probe are respectively disposed on the same side or both sides of the button cell battery. The ultrasonic signals reflected or transmitted by the button cell battery are collected to obtain a detection and receiving signal, which is then sent to the control and analysis processing equipment through the ultrasonic detection equipment. The driving device receives the control signal from the driving device and executes driving control to cause relative displacement between the ultrasonic transmitting probe and the ultrasonic receiving probe and the button cell battery.

7. The ultrasonic in-situ testing device for button batteries according to claim 6, characterized in that, The button cell ultrasonic in-situ testing device also includes a containment device; the containment device is filled with an insulating liquid for ultrasonic waves to be transmitted in the insulating liquid. The containing device includes 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 drive control of the drive 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 ultrasonic in-situ testing device for button batteries according to claim 1, characterized in that, The electrochemical detection system includes: an electrochemical testing instrument and a data analysis device; The electrochemical tester is connected to the button cell fixing device, applies a test signal to the button cell under test through the clamped area on the button cell, and receives the 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 testing of a coin cell battery based on the ultrasonic in-situ testing device for coin cells according to any one of claims 1-8, characterized in that, The detection method includes: The button cell to be tested is clamped and fixed in a button cell fixing device, such that at least 90% of the surface of the positive and / or negative electrode shells of the button cell has an unclamped exposed area and at most 10% has a clamped area; the unclamped exposed area completely covers the area where the electrode is located. A hollow conductive material is used as a fixing clamp for the positive and / or negative electrodes of the button cell, which also serves as a charging and discharging electrode connector. An ultrasonic testing system is used to perform in-situ ultrasonic testing of the coin cell in an insulating liquid medium through the exposed area on the coin cell. An electrochemical testing system is used to perform electrochemical tests on the coin cell under test through the clamped area on the coin cell.

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