A method and system for in-situ detection of lithium dendrites based on optical fiber sensor

Abstract

The present invention relates to the field of lithium battery technology, and specifically discloses a method for in-situ detection of lithium dendrites based on an optical fiber sensor, which comprises: evaporating the same metal material as the electrode to be detected on the surface of a first optical fiber sensor, and covering the surface of a second optical fiber sensor with a protective cover; passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending them outside the aluminum-plastic film to connect to a demodulation system; injecting electrolyte into the aluminum-plastic film; obtaining detection signals from the first optical fiber sensor and the second optical fiber sensor respectively through the demodulation system, and obtaining a lithium metal stress signal; and analyzing the lithium metal growth state in the lithium battery based on the measured electrochemical test signal of the lithium battery and the lithium metal stress signal. The present invention also discloses a lithium dendrite in-situ detection system based on an optical fiber sensor. The in-situ detection method for lithium dendrites based on an optical fiber sensor provided by the present invention can realize in-situ detection of lithium dendrites.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to an in-situ detection method for lithium dendrites based on an optical fiber sensor and an in-situ detection system for lithium dendrites based on an optical fiber sensor. Background Art

[0002] Within the existing energy framework, the foreseeable depletion of fossil fuels is increasingly in conflict with modern society's environmental priorities. The need to replace fossil fuels with pure electric drives in various scenarios is becoming increasingly apparent. The discovery of lithium iron phosphate and ternary materials has made lithium-ion batteries the most widely used energy storage device of this century. However, after decades of development, the rate of improvement in lithium-ion battery energy density has significantly slowed and is gradually approaching its theoretical limit. Lithium metal batteries (such as lithium-sulfur batteries) and new anode-free batteries are among the most promising next-generation high-energy-density storage devices, capable of meeting the requirements of emerging industries. However, issues such as volume expansion caused by uneven lithium metal deposition, SEI rupture, and "dead lithium" are primary limitations on their large-scale application.

[0003] Researchers have used a variety of methods to characterize and detect the deposition behavior of metallic lithium, such as scanning electron microscopy and cryo-electron microscopy. However, these technologies have the following problems: (1) they cannot perform in-situ detection on commonly used commercial battery systems; (2) to achieve in-situ detection, they can only use the method of constructing simulated batteries (such as nut batteries), which cannot reflect the actual behavior of lithium growth in battery configurations with real application value. Summary of the Invention

[0004] The present invention provides an in-situ detection method for lithium dendrites based on an optical fiber sensor and an in-situ detection system for lithium dendrites based on an optical fiber sensor, which solve the problem in the related art that lithium dendrites cannot be detected in-situ.

[0005] As a first aspect of the present invention, a method for in-situ detection of lithium dendrites based on an optical fiber sensor is provided, which comprises:

[0006] The surface of the first optical fiber sensor is evaporated with the same metal material as the electrode to be detected, and the surface of the second optical fiber sensor is covered with a protective cover, and one end of the first optical fiber sensor and the second optical fiber sensor are connected to a broadband light source;

[0007] Passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending out of the aluminum-plastic film to connect to the demodulation system, wherein the lithium battery is connected to the battery performance testing system;

[0008] Sealing the aluminum-plastic film and injecting electrolyte into the aluminum-plastic film;

[0009] Acquire detection signals of the first optical fiber sensor and the second optical fiber sensor respectively through the demodulation system, and obtain a lithium metal stress effect signal in the lithium battery;

[0010] The growth state of lithium metal in the lithium battery is analyzed based on the electrochemical test signal of the lithium battery measured by the battery performance test system and the lithium metal stress action signal.

[0011] Furthermore, the other ends of the first optical fiber sensor and the second optical fiber sensor are passed through the aluminum-plastic film on the lithium battery and extended out of the aluminum-plastic film, wherein the lithium battery is connected to the battery performance testing system, including:

[0012] The other ends of the first optical fiber sensor and the second optical fiber sensor are sequentially passed through the aluminum-plastic films on multiple lithium batteries and finally connected to the demodulation system, wherein the multiple lithium batteries are connected in series or in parallel and then connected to the battery performance testing system.

[0013] Furthermore, the step of passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending the other ends of the first optical fiber sensor out of the aluminum-plastic film comprises:

[0014] After the other ends of the first optical fiber sensor and the second optical fiber sensor are both placed in the protective sleeve, they are then inserted into the aluminum-plastic film on the lithium battery and extended out of the aluminum-plastic film.

[0015] Furthermore, the demodulation system is used to obtain the detection signals of the first optical fiber sensor and the second optical fiber sensor respectively, and obtain the lithium metal stress signal in the lithium battery, including:

[0016] The demodulation system demodulates and analyzes the first optical fiber sensor to obtain a first demodulation signal, and the demodulation system demodulates and analyzes the second optical fiber sensor to obtain a second demodulation signal, wherein the first demodulation signal includes a lithium metal stress signal and a temperature interference signal of the lithium battery, and the second demodulation signal includes a temperature interference signal;

[0017] The second demodulated signal is subtracted from the first demodulated signal to obtain a lithium metal stress effect signal in the lithium battery.

[0018] Furthermore, the metal material that is the same as the electrode to be tested includes any one of copper, gold and silver.

[0019] As another aspect of the present invention, a fiber optic sensor-based lithium dendrite in-situ detection system is provided, comprising: a first fiber optic sensor, a second fiber optic sensor, a broadband light source, a lithium battery, a demodulation system, and a battery testing system. The surface of the first fiber optic sensor is evaporated with the same metal material as the electrode to be detected, the surface of the second fiber optic sensor is covered with a protective cover, one end of the first fiber optic sensor and one end of the second fiber optic sensor are both connected to the broadband light source, the other ends of the first fiber optic sensor and the other ends of the second fiber optic sensor pass through the aluminum-plastic film on the lithium battery and extend outside the aluminum-plastic film to be connected to the demodulation system, and the battery testing system is connected to the lithium battery.

[0020] The demodulation system can obtain the detection signals of the first optical fiber sensor and the second optical fiber sensor, and obtain the lithium metal stress effect signal in the lithium battery. The battery performance testing system can measure the electrochemical test signal of the lithium battery.

[0021] Furthermore, the optical fiber sensor-based lithium dendrite in-situ detection system includes multiple lithium batteries, and the other end of the first optical fiber sensor and the other end of the second optical fiber sensor pass through the aluminum-plastic film on the multiple lithium batteries in sequence and are finally connected to the demodulation system, and the multiple lithium batteries are connected in series or in parallel and then connected to the battery performance testing system.

[0022] Furthermore, the optical fiber sensor-based lithium dendrite in-situ detection system also includes: a protective sleeve, which is sleeved on the other end of the first optical fiber sensor and the second optical fiber sensor, and is used to fix the other end of the first optical fiber sensor and the second optical fiber sensor together.

[0023] Furthermore, the metal material that is the same as the electrode to be tested includes any one of copper, gold and silver.

[0024] The in-situ detection method for lithium dendrites based on optical fiber sensors provided by the present invention monitors the surface state of the electrode to be detected through two optical fiber sensors. On the basis of maintaining the configuration of a commercially available battery, it can monitor the growth of lithium dendrites on the electrode surface in situ and compare it with the electrochemical test signal at the same time. While ensuring that the battery operates in a conventional form, non-destructive monitoring is performed to read the stress changes on the electrode surface, which can be used for basic scientific research and failure warning. In addition, due to the use of two optical fiber sensors, the signal of the stress-sensitive response main optical fiber can be decoupled through the signal of the temperature-sensitive response comparison optical fiber, and the signal of the main stress effect can be extracted, thereby ensuring the accuracy of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

[0026] Figure 1 This is a flow chart of the in-situ detection method for lithium dendrites based on optical fiber sensors provided by the present invention.

[0027] Figure 2 A schematic structural diagram of an embodiment of the in-situ detection system for lithium dendrites based on optical fiber sensors provided by the present invention.

[0028] Figure 3 A schematic structural diagram of another embodiment of the in-situ detection system for lithium dendrites based on optical fiber sensors provided by the present invention. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0032] In this embodiment, a method for in-situ detection of lithium dendrites based on an optical fiber sensor is provided. Figure 1 is a flow chart of a method for in-situ detection of lithium dendrites based on an optical fiber sensor according to an embodiment of the present invention. Figure 2 FIG. 1 is a schematic structural diagram of a lithium dendrite in-situ detection system based on an optical fiber sensor according to an embodiment of the present invention. Figure 1 and Figure 2 Shown, including:

[0033] S110, evaporating the same metal material as the electrode to be detected on the surface of the first optical fiber sensor, covering the surface of the second optical fiber sensor with a protective cover, and connecting one end of the first optical fiber sensor and the second optical fiber sensor to a broadband light source 14;

[0034] It should be noted that by covering the surface of the second optical fiber sensor with a protective cover, the second optical fiber sensor can be prevented from responding to the stress of the lithium-ion battery, so that it only responds to the temperature. In this way, the first optical fiber sensor has the same metal material as the electrode to be detected evaporated on its surface to ensure the electrodeposition behavior, thereby responding to the stress of the lithium metal.

[0035] S120, passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film 11 on the lithium battery and extending out of the aluminum-plastic film 11 to connect to the demodulation system 15, wherein the lithium battery is connected to the battery performance testing system 16;

[0036] like Figure 2 As shown, the other ends of the first optical fiber sensor and the second optical fiber sensor are put together and then pass through the micropores 12 on the aluminum-plastic film 11 on the lithium battery to enter the interior of the lithium battery, then approach the electrode sheet to be tested, and pass through the outside of the aluminum-plastic film to connect to the demodulation system. At the same time, the two tabs of the lithium battery are connected to the battery performance test system.

[0037] It should be noted that the aluminum-plastic film 11 is the shell of the battery (including but not limited to soft-pack batteries and cylindrical batteries), and micropores 12 are opened on the surface of the shell, and two optical fiber sensors can be inserted into the micropores 12.

[0038] S130, sealing the aluminum-plastic film 11 and injecting electrolyte into the aluminum-plastic film 11;

[0039] It should be noted that sealing can be performed using a sealing agent, which includes but is not limited to epoxy resin and battery termination tape.

[0040] It should be understood that after the electrolyte is injected into the aluminum-plastic film, the lithium battery can enter a working state under the action of the battery performance testing system, thereby achieving its electrochemical performance test and lithium metal stress detection.

[0041] S140, acquiring detection signals from the first optical fiber sensor and the second optical fiber sensor respectively through the demodulation system, and obtaining a lithium metal stress effect signal in the lithium battery;

[0042] S150 , analyzing the growth state of lithium metal in the lithium battery according to the electrochemical test signal of the lithium battery measured by the battery performance test system and the lithium metal stress action signal.

[0043] The in-situ detection method for lithium dendrites based on optical fiber sensors provided in an embodiment of the present invention monitors the surface state of the electrode to be detected through two optical fiber sensors. On the basis of maintaining the configuration of a commercially available battery, it can monitor the growth of lithium dendrites on the electrode surface in situ and compare it with the electrochemical test signal at the same time. While ensuring that the battery operates in a conventional form, non-destructive monitoring is performed to read the stress changes on the electrode surface, which can be used for basic scientific research and failure warning. In addition, due to the use of two optical fiber sensors, the signal of the stress-sensitive response main optical fiber can be decoupled by comparing the signal of the temperature-sensitive response contrast optical fiber, and the signal of the main stress effect can be extracted, thereby ensuring the accuracy of the signal.

[0044] Specifically, the other ends of the first optical fiber sensor and the second optical fiber sensor are passed through the aluminum-plastic film on the lithium battery and extended out of the aluminum-plastic film, wherein the lithium battery is connected to the battery performance testing system, including:

[0045] The other ends of the first optical fiber sensor and the second optical fiber sensor are sequentially passed through the aluminum-plastic films on multiple lithium batteries and finally connected to the demodulation system, wherein the multiple lithium batteries are connected in series or in parallel and then connected to the battery performance testing system.

[0046] like Figure 3 As shown, continuous distributed monitoring of multiple lithium batteries can be achieved simultaneously. In this embodiment, the optical fiber is installed in the protective sleeve 13 and passed into the hole of the aluminum-plastic film. The lithium battery is then packaged and filled with liquid. The independent lithium batteries are connected in series through the optical fiber sensor group 20 (including the first optical fiber sensor and the second optical fiber sensor). After collecting the composite signal, it is demodulated and analyzed by the demodulation system. In addition, multiple lithium batteries can be connected in series or in parallel. The specific selection is made according to needs and is not set here. The battery testing system is connected to the lithium battery group connected in series or the lithium battery group connected in parallel to detect the electrochemical signal, and finally distributed continuous electrode status monitoring of the battery group can be achieved.

[0047] Specifically, passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending the other ends of the first optical fiber sensor and the second optical fiber sensor out of the aluminum-plastic film includes:

[0048] After the other ends of the first optical fiber sensor and the second optical fiber sensor are placed in the protective sleeve 13, they are then inserted into the aluminum-plastic film on the lithium battery and extended out of the aluminum-plastic film.

[0049] It should be understood that before penetrating the aluminum-plastic film of the lithium battery, the other end of the first optical fiber sensor and the other end of the second optical fiber sensor can be fixed by a protective sleeve 13. Similarly, when extending out of the aluminum-plastic film 11, another protective sleeve 13 can be used to fix the other end of the extended first optical fiber sensor and the other end of the second optical fiber sensor.

[0050] It should be noted that the protective sleeve 13 and the aluminum-plastic film 11 can be bonded and sealed with epoxy resin to prevent leakage after liquid injection.

[0051] Specifically, the demodulation system is used to obtain the detection signals of the first optical fiber sensor and the second optical fiber sensor respectively, and obtain the lithium metal stress signal in the lithium battery, including:

[0052] The demodulation system demodulates and analyzes the first optical fiber sensor to obtain a first demodulation signal, and the demodulation system demodulates and analyzes the second optical fiber sensor to obtain a second demodulation signal, wherein the first demodulation signal includes a lithium metal stress signal and a temperature interference signal of the lithium battery, and the second demodulation signal includes a temperature interference signal;

[0053] The second demodulated signal is subtracted from the first demodulated signal to obtain a lithium metal stress effect signal in the lithium battery.

[0054] In some embodiments, the metal material that is the same as the electrode to be detected includes any one of copper, gold and silver.

[0055] It should be understood that the metal material that is the same as the electrode to be tested also includes various alloys.

[0056] In summary, the fiber-optic sensor-based in-situ detection method for lithium dendrites provided by the present invention utilizes a stress-sensitive primary fiber-optic sensor and a temperature-sensitive comparison fiber-optic sensor to continuously monitor the electrode surface state in real time, combined with electrochemical test signals, to achieve non-destructive in-situ monitoring. This method offers advantages such as high measurement accuracy, strong scalability, and low cost.

[0057] As another embodiment of the present invention, a lithium dendrite in-situ detection system based on an optical fiber sensor is provided, wherein Figure 2As shown, it includes: a first optical fiber sensor, a second optical fiber sensor, a broadband light source 14, a lithium battery, a demodulation system 15 and a battery testing system 16. The surface of the first optical fiber sensor is evaporated with the same metal material as the electrode to be detected, and the surface of the second optical fiber sensor is covered with a protective cover. One end of the first optical fiber sensor and one end of the second optical fiber sensor are both connected to the broadband light source 14. The other end of the first optical fiber sensor and the other end of the second optical fiber sensor pass through the aluminum-plastic film 11 on the lithium battery and extend out of the aluminum-plastic film 11 to be connected to the demodulation system 15. The battery testing system 16 is connected to the lithium battery.

[0058] The demodulation system 15 can obtain the detection signals of the first optical fiber sensor and the second optical fiber sensor, and obtain the lithium metal stress effect signal in the lithium battery. The battery performance testing system 16 can measure the electrochemical test signal of the lithium battery.

[0059] The in-situ detection system for lithium dendrites based on optical fiber sensors provided by an embodiment of the present invention monitors the surface state of the electrode to be detected through two optical fiber sensors. On the basis of maintaining the configuration of a commercially available battery, it can monitor the growth of lithium dendrites on the electrode surface in situ and compare it with the electrochemical test signal at the same time. While ensuring that the battery operates in a conventional form, non-destructive monitoring is performed to read the stress changes on the electrode surface, which can be used for basic scientific research and failure warning. In addition, due to the use of two optical fiber sensors, the signal of the stress-sensitive response main optical fiber can be decoupled by comparing the signal of the temperature-sensitive response contrast optical fiber, and the signal of the main stress effect can be extracted, thereby ensuring the accuracy of the signal.

[0060] Specifically, if Figure 3 As shown, the fiber optic sensor-based lithium dendrite in-situ detection system includes multiple lithium batteries, and the other end of the first fiber optic sensor and the other end of the second fiber optic sensor pass through the aluminum-plastic films on the multiple lithium batteries in sequence and are finally connected to the demodulation system, and the multiple lithium batteries are connected in series or in parallel and then connected to the battery performance testing system.

[0061] Specifically, the optical fiber sensor-based lithium dendrite in-situ detection system also includes: a protective sleeve 13, which is sleeved on the other end of the first optical fiber sensor and the second optical fiber sensor, and is used to fix the other end of the first optical fiber sensor and the second optical fiber sensor together.

[0062] In some embodiments, the metal material that is the same as the electrode to be detected includes any one of copper, gold and silver.

[0063] Regarding the specific working principle of the in-situ detection system for lithium dendrites based on optical fiber sensors provided in an embodiment of the present invention, reference can be made to the description of the in-situ detection method for lithium dendrites based on optical fiber sensors in the previous text, which will not be repeated here.

[0064] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for in-situ detection of lithium dendrites based on optical fiber sensors, characterized in that: include: The surface of the first optical fiber sensor is evaporated with the same metal material as the electrode to be detected, and the surface of the second optical fiber sensor is covered with a protective cover, and one end of the first optical fiber sensor and the second optical fiber sensor are connected to a broadband light source; Passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending out of the aluminum-plastic film to connect to the demodulation system, wherein the lithium battery is connected to the battery performance testing system; Sealing the aluminum-plastic film and injecting electrolyte into the aluminum-plastic film; Acquire detection signals of the first optical fiber sensor and the second optical fiber sensor respectively through the demodulation system, and obtain a lithium metal stress effect signal in the lithium battery; Analyzing the growth state of lithium metal in the lithium battery based on the electrochemical test signal of the lithium battery measured by the battery performance test system and the lithium metal stress action signal; The method of acquiring the detection signals of the first optical fiber sensor and the second optical fiber sensor respectively through the demodulation system and obtaining the lithium metal stress signal in the lithium battery includes: The demodulation system demodulates and analyzes the detection signal obtained from the first optical fiber sensor to obtain a first demodulated signal, and the demodulation system demodulates and analyzes the detection signal obtained from the second optical fiber sensor to obtain a second demodulated signal, wherein the first demodulated signal includes a lithium metal stress signal and a temperature interference signal of the lithium battery, and the second demodulated signal includes a temperature interference signal; The second demodulated signal is subtracted from the first demodulated signal to obtain a lithium metal stress effect signal in the lithium battery.

2. The in-situ detection method for lithium dendrites based on optical fiber sensor according to claim 1, characterized in that: Passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending the other ends of the first optical fiber sensor through the aluminum-plastic film, wherein the lithium battery is connected to the battery performance testing system, comprises: The other ends of the first optical fiber sensor and the second optical fiber sensor are sequentially passed through the aluminum-plastic films on multiple lithium batteries and finally connected to the demodulation system, wherein the multiple lithium batteries are connected in series or in parallel and then connected to the battery performance testing system.

3. The in-situ detection method for lithium dendrites based on an optical fiber sensor according to claim 1 or 2, characterized in that: Passing the other ends of the first optical fiber sensor and the second optical fiber sensor through the aluminum-plastic film on the lithium battery and extending the other ends of the first optical fiber sensor and the second optical fiber sensor out of the aluminum-plastic film comprises: After the other ends of the first optical fiber sensor and the second optical fiber sensor are both placed in the protective sleeve, they are then inserted into the aluminum-plastic film on the lithium battery and extended out of the aluminum-plastic film.

4. The in-situ detection method for lithium dendrites based on optical fiber sensor according to claim 1, characterized in that: The metal material that is the same as the electrode to be detected includes any one of copper, gold and silver.

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