Optical fiber sensor implantation evaluation and lossless implantation method and system

Abstract

The invention discloses an optical fiber sensor implantation evaluation and lossless implantation method and system, and relates to the technical field of lithium ion battery monitoring and manufacturing processes, and the method comprises the steps: calculating the shortest distance between each monitoring node in a to-be-monitored region and a to-be-evaluated optical fiber implantation arrangement path; determining a monitoring satisfaction degree according to the shortest distance of each monitoring node; the average value of monitoring satisfaction of all monitoring nodes in a to-be-monitored area is taken as a space coverage index, and a multiplication penalty factor attenuated along with the total length index of the optical fiber is combined to determine a monitoring performance score of a to-be-evaluated optical fiber implantation arrangement path, so that an optimal optical fiber implantation arrangement scheme is determined. And by improving the cathode structure and optimizing the manufacturing process, safe integration of the optical fiber sensor in the cell core area is realized without influencing the battery performance, and the technical problems that the optical fiber sensor layout design lacks scientific basis and the cell is easy to damage in the implantation process in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery monitoring and manufacturing process technology, and in particular to a fiber optic sensor implantation evaluation, non-destructive implantation method and system. Background Technology

[0002] With the rapid development of new energy vehicles and large-scale energy storage industries, the safety, performance, and lifespan of lithium-ion batteries, as the core energy storage unit, have become key factors determining the industry's development. Real-time and accurate monitoring of the battery's internal state, especially core parameters such as temperature and strain, is a fundamental technical means to improve the efficiency of the Battery Management System (BMS), provide early warning of thermal runaway, and extend battery life. Against this backdrop, fiber optic sensors, due to their small size (down to the micrometer level), resistance to electromagnetic interference, high sensitivity, and ability to perform distributed measurements, have shown great application potential in the field of lithium-ion battery internal monitoring.

[0003] Currently, research on applying fiber optic sensors to monitor the internal state of lithium-ion batteries has made some progress. For example, in cylindrical lithium-ion batteries with a central pore, existing technologies have attempted to embed fiber optic sensors within the core, successfully monitoring internal temperature and strain. However, stacked (pouch) lithium-ion batteries, one of the mainstream technologies in power batteries and energy storage, are composed of highly compacted layers of positive, negative, and separator sheets, lacking significant inherent gaps. This presents a severe technical challenge for the internal embedding of fiber optic sensors. To circumvent this problem, some existing technologies propose placing the fiber optic sensor in the gap between the cell stack and the aluminum-plastic film shell. While this approach allows for embedding, the sensor does not actually enter the active area of ​​the cell, making it impossible to directly and accurately obtain temperature and strain signals from the core area. As battery technology develops towards larger capacity and higher rate capabilities, the problems of heat accumulation and uneven mechanical stress distribution within a single cell (e.g., exceeding 100Ah) during operation are becoming increasingly prominent. The temperature difference between the core area and the surface can reach over 10°C, and the stress gradient is also very significant. Therefore, the limitations of this surface monitoring method are becoming increasingly apparent, making it difficult to meet the requirements of next-generation high-performance batteries for precise safety management.

[0004] In conclusion, although the industry has recognized the importance of fiber optic in-situ monitoring, its application in the field of stacked lithium-ion batteries still faces a series of technical bottlenecks that urgently need to be addressed. These bottlenecks hinder the realization of reliable and efficient in-situ precision monitoring systems.

[0005] Firstly, there is a lack of scientific design methods for sensor deployment schemes. How can optical fibers be laid in a two-dimensional or three-dimensional space to minimize the increased cost, process complexity, and potential impact on battery performance caused by the total fiber length, while ensuring monitoring coverage and accuracy? Current technologies largely rely on experience for layout, lacking quantifiable performance evaluation indicators for scientific guidance and optimization.

[0006] Secondly, there is a lack of mature, non-destructive implantation technology for sensors. Forcibly implanting optical fibers between tightly packed electrode layers inevitably creates localized gaps, disrupting the uniform transport channels for lithium ions, leading to a decrease in battery electrochemical performance and long-term reliability. Furthermore, the thermo-press sealing step during battery packaging can easily cause mechanical damage to the delicate optical fibers, affecting the final yield and signal transmission stability. Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes a fiber optic sensor implantation evaluation, non-destructive implantation method, and system. By comprehensively monitoring performance evaluation indicators, it guides the optimal spatial layout of the fiber optic sensor. Through improvements to the negative electrode structure and optimization of the manufacturing process, it achieves safe integration of the fiber optic sensor in the core area of ​​the battery cell without affecting battery performance. This solves the technical problems of the lack of scientific basis for fiber optic sensor layout design and the easy damage to the battery cell during the implantation process in the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for evaluating the implantation of an optical fiber sensor, comprising: For each monitoring node within the monitoring area, calculate the shortest distance from the fiber optic cable implantation path to be evaluated; The monitoring satisfaction level is determined based on the shortest distance at each monitoring node. The average monitoring satisfaction of all monitoring nodes in the area to be monitored is used as the spatial coverage index. Combined with the multiplicative penalty factor that decreases exponentially with the total length of the optical fiber, the monitoring performance score of the optical fiber implantation path to be evaluated is determined, and the optimal optical fiber implantation scheme is determined accordingly.

[0009] As an alternative implementation method, monitoring satisfaction is recommended. S ( r )for: ; In the formula, r 0 represents the feature monitoring radius, signifying the critical distance between satisfaction and dissatisfaction; k The attenuation coefficient; r The shortest distance between each monitoring node and the fiber optic implantation path to be evaluated.

[0010] As an alternative implementation method, the multiplication penalty factorP ( L C )for: In the formula, L C This represents the total length of the current fiber optic installation and deployment scheme; β The coefficient is the exponential penalty coefficient. L char The characteristic length; The monitoring performance score is obtained by multiplying the spatial coverage index and the multiplication penalty factor.

[0011] Secondly, the present invention provides a method for non-destructive implantation of an optical fiber sensor, comprising: A single-sided coated negative electrode sheet is prepared by coating an active material layer on one side of the current collector with the negative electrode material. According to the optimal fiber optic implantation arrangement scheme, microgrooves are prefabricated on the base surface, and the groove depth is matched with the diameter of the fiber optic sensor, so as to embed the fiber optic sensor into the microgrooves; the optimal fiber optic implantation arrangement scheme is obtained by using the fiber optic sensor implantation evaluation method described in the first aspect. Assemble a single-sided coated negative electrode sheet and a base for embedding an optical fiber sensor to form a composite negative electrode; The composite negative electrode, separator, and positive electrode are stacked sequentially according to the stacking process before battery encapsulation.

[0012] As an alternative implementation, a substrate with microgrooves is prepared using microfabrication or 3D printing methods; two single-sided coated negative electrode sheets are assembled with the substrate containing the fiber optic sensor to form a composite negative electrode structure, the structure of which is negative electrode active material layer - current collector - substrate - current collector - negative electrode active material layer.

[0013] As an alternative implementation, the battery encapsulation process includes: pre-fabricating one or more openings on the bottom side of the battery aluminum-plastic film according to the lead-out point position of the fiber optic sensor in the fiber optic implantation arrangement scheme. The diameter of the opening matches the diameter of the fiber optic cable, and the position of the opening corresponds to the lead-out end of the fiber optic cable on the composite negative electrode base to lead out the fiber optic connector. At the same time, it is planned in the non-core active area of ​​the battery cell.

[0014] As an alternative implementation method, the battery packaging process also includes: Top sealing area encapsulation: Heat sealing technology is used to seal the top sealing area by controlling the heat sealing temperature and pressure, ensuring the bonding between the electrode end and the battery aluminum-plastic film; and the optical fiber lead-out path avoids the top sealing area and extends along the edge of the cell to the bottom opening; Side sealing: The aluminum-plastic film on both sides of the battery is sealed by heat sealing equipment, which controls the heat sealing temperature and pressure.

[0015] As an alternative implementation method, the battery packaging process also includes: One-seal encapsulation: First, the optical fiber is passed through the reserved opening. At the end away from the tab, i.e. the one-seal area, a preliminary seal is performed, leaving an injection port. At the same time, a ring of sealant is pre-applied around the opening for preliminary isolation. Then, electrolyte is injected through the injection port to complete the preliminary sealing of the one-seal area. Secondary sealing area and opening sealing: After the battery has undergone formation and venting processes, the final vacuum heat sealing is performed to complete the secondary sealing area encapsulation and ensure that the battery cell is completely sealed.

[0016] Thirdly, the present invention provides a fiber optic sensor implantation evaluation system, comprising: The distance assessment module is configured to calculate the shortest distance from the fiber optic implantation path to each monitoring node within the monitoring area. The satisfaction assessment module is configured to determine monitoring satisfaction based on the shortest distance to each monitoring node; The performance evaluation module is configured to use the average monitoring satisfaction of all monitoring nodes in the area to be monitored as the spatial coverage index, and combine it with a multiplicative penalty factor that decreases exponentially with the total length of the optical fiber to determine the monitoring performance score of the optical fiber implantation path to be evaluated, and to determine the optimal optical fiber implantation scheme based on this score.

[0017] Fourthly, the present invention provides a lithium-ion battery, comprising: prepared using the non-destructive implantation method of the fiber optic sensor described in the second aspect.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: To address the lack of scientific design basis for fiber optic implantation layout schemes, this invention provides a fiber optic sensor implantation evaluation method. This method guides the optimal spatial layout of fiber optic sensors through comprehensive monitoring performance evaluation indicators. These indicators combine a spatial coverage index, which characterizes coverage, with a multiplicative penalty factor that decreases exponentially with the total fiber length. This enables a scientific evaluation of different fiber optic implantation layout schemes and establishes a unified and quantitative evaluation index for scientifically evaluating the comprehensive effectiveness of any given fiber optic implantation layout scheme.

[0019] After determining the optimal fiber optic implantation layout, this invention addresses the problem of damaging the battery cell structure and adversely affecting lithium-ion transport performance during fiber optic sensor implantation by improving the negative electrode structure and optimizing the manufacturing process. It provides a non-destructive fiber optic sensor implantation method. Compared to existing technologies, this invention constructs a composite negative electrode structure consisting of a grooved base and two single-sided coated negative electrode sheets. The fiber optic sensor is embedded in the microgroove of the base, achieving safe integration of the fiber optic sensor in the core area of ​​the battery cell without affecting battery performance. This avoids the risks of damaging the battery cell structure and affecting lithium-ion transport performance associated with traditional implantation methods. Furthermore, the fiber optic sensor, located in the core area of ​​the battery cell, can directly acquire temperature and strain data from key components, thereby effectively improving the accuracy and representativeness of the monitoring data.

[0020] In the non-destructive implantation method for fiber optic sensors of this invention, the encapsulation process involves directly opening a hole on the bottom side of the battery's aluminum-plastic film to lead out the fiber optic connector, and employing a secondary reinforced sealing method. This not only effectively solves the sealing problem at the lead-out point but also reduces potential signal loss and encapsulation complexity by shortening the redundant path of the fiber optic cable within the encapsulation body, thereby improving the yield and reliability of the implanted fiber optic connector. This invention enables non-destructive implantation of fiber optic sensors in the core area of ​​stacked batteries and in-situ parameter monitoring, improving battery safety and management efficiency. It is applicable to fiber optic implantation in the manufacturing process of full-size stacked lithium-ion batteries.

[0021] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 The overall flowchart of fiber optic sensor implantation evaluation and non-destructive implantation provided by this invention; Figure 2 This is a flowchart of the fiber optic sensor implantation evaluation method provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the monitoring area grid nodes provided in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the non-destructive implantation method for fiber optic sensors provided in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the grid nodes in the battery monitoring area provided in Verification Example 1 of the present invention; Figure 6 This is a spatial distribution cloud map of the node monitoring satisfaction level corresponding to the optical fiber implantation layout path scheme (a) provided in Example 1 of the present invention. Figure 7 This is a spatial distribution cloud map of node monitoring satisfaction corresponding to the optical fiber implantation layout path scheme (b) provided in Example 1 of the present invention. Figure 8 This is a spatial distribution cloud map of node monitoring satisfaction corresponding to the optical fiber implantation layout path scheme (c) provided in Verification Example 1 of the present invention. Figure 9 This is a spatial distribution cloud map of node monitoring satisfaction corresponding to the optical fiber implantation layout path scheme (d) provided in Example 1 of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that the terms “comprising” and “including”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0028] Example 1 To address the lack of scientific design basis for fiber optic implantation and deployment schemes, this embodiment proposes a fiber optic sensor implantation evaluation method, aiming to establish a unified and quantitative evaluation index for scientifically evaluating the comprehensive performance of any given fiber optic implantation and deployment scheme.

[0029] Combination Figures 1-2 As shown, it specifically includes: For each monitoring node within the monitoring area, calculate the shortest distance from the fiber optic cable implantation path to be evaluated; The monitoring satisfaction level is determined based on the shortest distance at each monitoring node. The average monitoring satisfaction of all monitoring nodes in the area to be monitored is used as the spatial coverage index. Combined with the multiplicative penalty factor that decreases exponentially with the total length of the optical fiber, the monitoring performance score of the optical fiber implantation path to be evaluated is determined, and the optimal optical fiber implantation scheme is determined accordingly.

[0030] Specifically: like Figure 3 As shown, to facilitate quantitative calculations, the continuous monitoring region Ω (such as a plane of a battery) is spatially discretized.

[0031] Specifically, a virtual, uniformly distributed grid is established within the area to be monitored, Ω, and the intersections of the grid are the monitoring nodes P. Each monitoring node represents the monitoring status of a small area around it. By evaluating the overall status of all monitoring nodes, the monitoring effect of the entire area to be monitored can be approximately represented.

[0032] Assume that the area to be monitored Ω contains N monitoring nodes. P = { p 1, p 2, ..., p N}, where each monitoring node p i The coordinates are ( x i , y i For any monitoring node in the grid. p Its monitoring satisfaction depends on its shortest distance from the optical fiber.

[0033] Assume the fiber optic implantation path is a continuous curve. C This means that for any monitoring node p Calculate the fiber curve C Euclidean shortest distance r : (1); in, q It is a curve C Any point on it.

[0034] Then, define the monitoring satisfaction function for the monitoring nodes. S ( r The function has a range of [0, 1], where 1 represents optimal monitoring and 0 represents no monitoring.

[0035] (2); In the formula, r 0 represents the feature monitoring radius, signifying the critical distance between satisfactory and unsatisfactory conditions. r =r At 0 o'clock, S( r 0) = 0.5; k The attenuation coefficient controls the steepness of the function curve. k The larger the value, the more drastic the transition of satisfaction from 1 to 0, meaning that the greater the satisfaction level, the more intense the transition from 1 to 0. r The greater the distance penalty, the greater the penalty.

[0036] The overall monitoring performance of a fiber optic deployment scheme depends on the monitoring satisfaction of all monitoring nodes in the area to be monitored, which is defined as the arithmetic mean of the monitoring satisfaction of all monitoring nodes.

[0037] For a given fiber optic implantation path, the curve C and grid P Spatial coverage index I cov The calculation is as follows: (3); in, p i It is the first in the grid i One monitoring node, N This is the total number of nodes; I cov The value range is also between [0, 1]. The closer it is to 1, the better the overall coverage performance.

[0038] Furthermore, to avoid blindly pursuing the use of infinitely long or overly complex optical fibers... I cov To approximate 1, a penalty is introduced on the total fiber length. Specifically, a multiplicative penalty factor is defined that decreases exponentially with the total fiber length. P ( L C The range of the penalty factor is (0, 1]. L C =0 is 1, and so on L C It increases and approaches 0.

[0039] (4); In the formula, L C This represents the total length of the current fiber optic installation and deployment scheme; β The exponential penalty coefficient is a dimensionless parameter used to adjust the severity of the length penalty. L char The characteristic length (such as the diagonal length of a battery) is used for normalization. L C .

[0040] Finally, the spatial coverage index and the multiplicative penalty factor are combined to obtain the final monitoring performance score. Q ; (5).

[0041] The Q-value, as a normalized comprehensive score, can scientifically and objectively evaluate the advantages and disadvantages of different fiber optic implantation and placement schemes, thus providing decisive data support for achieving the optimal sensor spatial layout.

[0042] Example 2 After determining the optimal fiber optic implantation layout, this embodiment solves the problem of damaging the cell structure and adversely affecting lithium-ion transport performance during fiber optic implantation by improving the negative electrode structure and optimizing the manufacturing process, thus providing a non-destructive implantation method for fiber optic sensors.

[0043] Combination Figure 1 and Figure 4 As shown, the specific steps include: A single-sided coated negative electrode sheet is prepared by coating an active material layer on one side of the current collector with the negative electrode material. According to the optimal fiber optic implantation arrangement scheme, microgrooves are prefabricated on the base surface, and the groove depth is matched with the diameter of the fiber optic sensor, so as to embed the fiber optic sensor into the microgrooves. Assemble a single-sided coated negative electrode sheet and a base for embedding an optical fiber sensor to form a composite negative electrode; The composite negative electrode, separator, and positive electrode are stacked sequentially according to the stacking process before battery encapsulation. The optimal fiber optic implantation layout scheme is obtained by using the fiber optic sensor implantation evaluation method described in Example 1.

[0044] Specifically: (1) Preparation of single-sided coated negative electrode sheet.

[0045] Two single-sided coated negative electrode sheets are prepared by coating an active material layer on one side of a copper foil current collector using negative electrode materials such as graphite.

[0046] Each negative electrode structure consists of a negative electrode active material layer and a current collector, with the coating thickness controlled between 50-150 μm to ensure the uniformity of the subsequent stacked structure and the stability of its electrochemical performance.

[0047] (2) Base fabrication and fiber optic sensor integration.

[0048] The base is designed according to the fiber optic implantation path and diameter. The base is preferably made of a polymer material with good mechanical strength and chemical stability, such as ABS plastic (ABS plastic is a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S), polyimide, polyethylene terephthalate, or a photosensitive resin with similar properties that is resistant to electrolyte corrosion.

[0049] The base can be fabricated and the fiber optic sensor can be embedded using one of the following two methods.

[0050] Microfabrication method: Microgrooves are pre-fabricated on the substrate surface using microfabrication techniques such as laser engraving and precision scribing. The groove depth matches the diameter of the fiber optic sensor (typically 0.1mm-1mm), and the groove width error is controlled within ±50μm. After processing, surface residues are removed by plasma cleaning to improve surface adhesion. The fiber optic sensor is embedded in the microgrooves and fixed using a low-temperature curing adhesive (such as epoxy-based adhesives with a curing temperature below 80℃) to ensure a tight fit between the fiber optic sensor and the substrate without protruding from the substrate surface.

[0051] 3D Printing Method: High-precision additive manufacturing technologies (such as Fused Deposition Modeling (FDM) for thermoplastics like ABS, or StereoLithography Apparatus (SLA) / Digital Light Processing (DLP) for photosensitive resins) are used to print a substrate with pre-fabricated microgrooves. Printing parameters are set according to the selected technology to ensure precise matching between the microgroove depth and the diameter of the fiber optic sensor, with the groove width error controlled within ±50μm, and a smooth, structurally intact substrate surface. After printing, plasma cleaning, fiber embedding, and low-temperature curing are performed for fixation.

[0052] (3) Composite negative electrode assembly.

[0053] Two single-sided coated negative electrode sheets are assembled with a base embedded with an optical fiber sensor to form a composite negative electrode structure, namely: negative electrode active material layer - current collector - base - current collector - negative electrode active material layer.

[0054] During assembly, the negative electrode current collector is bonded to the base using high-performance conductive adhesive (such as silver-based or carbon-based conductive adhesive with a conductivity ≥10). 4 The conductive adhesive (S / m) is uniformly applied to the contact surface between the current collector and the substrate, with a coating thickness controlled between 5-20 μm. The curing temperature of the conductive adhesive is controlled between 60-100℃, and the curing time is 10-30 minutes to ensure bonding strength (shear strength ≥5MPa).

[0055] Precision pressing technology is employed, using constant pressure pressing equipment to control the pressing pressure at 0.3-1.5 MPa and the pressing time at 5-15 seconds, ensuring that there are no air bubbles or pores between each layer. During the pressing process, the flatness of the pressing surface must be monitored (error ≤10μm) to avoid displacement of the fiber optic sensor or deformation of the base due to uneven pressure.

[0056] Assembly is carried out in a cleanroom (cleanliness level ≥ ISO5), with the ambient temperature controlled at 20-25℃ and relative humidity below 30% to prevent dust or moisture from contaminating the conductive adhesive or electrode structure. After assembly, the internal structure of the composite negative electrode is inspected using ultrasonic imaging or X-ray inspection to confirm the absence of bubbles, cracks, or fiber optic sensor misalignment.

[0057] (4) Cell stacking.

[0058] The composite negative electrode, separator, and positive electrode are stacked sequentially using conventional lamination processes to form the basic unit of negative electrode-separator-positive electrode. During the lamination process, a constant-pressure lamination device is used to control the lamination pressure within the range of 0.5-2MPa, ensuring that the fiber optic sensor in the composite negative electrode does not shift or break, while maintaining the compactness and consistency of the cell structure.

[0059] (5) Battery packaging.

[0060] Pre-drilled openings: Based on the fiber optic sensor lead-out point location in the fiber optic implantation layout plan, one or more micro-openings are pre-drilled on the bottom side of the aluminum-plastic film (away from the tab side). The opening locations correspond to the fiber optic lead-out endpoints on the composite negative electrode base, and are planned within the non-core active area of ​​the cell to ensure that the structural strength of the battery is not affected. The opening diameter is determined based on the fiber optic diameter (approximately 0.1-1 mm).

[0061] Top sealing area encapsulation: Heat sealing technology is used, with the heat sealing temperature controlled at 160-200℃ and the pressure at 0.2-0.8MPa, to seal the top sealing area and ensure a tight bond between the electrode tip and the aluminum-plastic film. The optical fiber lead-out path is designed to avoid the top sealing area and extend along the edge of the cell to the bottom opening to avoid pressure.

[0062] Side sealing: The aluminum-plastic film is sealed on both sides using heat sealing equipment. The heat sealing temperature is 150-190℃ and the pressure is 0.3-1.0MPa.

[0063] First sealing: A preliminary seal is performed at the end furthest from the tab (i.e., the first sealing area), leaving an injection port. Before this step, the optical fiber is passed through the pre-drilled opening. To prevent leakage during subsequent injection, a ring of flexible sealant (such as silicone sealant) is pre-applied around the opening for initial isolation. Then, electrolyte (such as carbonate-based electrolyte) is injected, and the first sealing area is pre-heat-sealed, with the temperature controlled at 140-180℃ and the pressure at 0.2-0.6MPa.

[0064] Secondary sealing area and opening sealing: After the battery has undergone formation, venting and other processes, the final vacuum heat sealing is carried out to complete the secondary sealing area encapsulation, ensuring that the battery cells are completely sealed. The temperature is 150-190℃ and the pressure is 0.3-0.8MPa.

[0065] In this embodiment, the final sealing of the fiber optic lead-out opening is a crucial step. This step employs a high-precision dispensing process, using a polymeric sealing material (such as electrolyte-resistant epoxy resin or silicone sealant) to fill and cover both the inner and outer sides of the opening, followed by thermosetting or UV curing under a specific pressure (0.1-0.5 MPa). This step aims to create a long-term, reliable sealing structure with excellent airtightness and sufficient mechanical strength, ensuring battery safety and long-term stability of fiber optic signal transmission. Finally, the lead-out fiber end is connected to an external monitoring system.

[0066] Compared with existing technologies, the above-mentioned solution in this embodiment achieves non-destructive implantation of fiber optic sensors inside stacked lithium-ion batteries by improving the negative electrode structure and optimizing the manufacturing process. This avoids the risks of damaging the cell structure and affecting lithium-ion transport performance associated with traditional implantation methods. The fiber optic sensor is located in the core area of ​​the cell and can directly acquire temperature and strain data of key parts, thereby effectively improving the accuracy and representativeness of the monitoring data. The packaging process, by directly opening holes on the bottom side of the aluminum-plastic film and using a secondary reinforced sealing method, not only effectively solves the sealing problem of the lead-out points, but also reduces potential signal loss and packaging complexity by shortening the redundant path of the optical fiber in the package, thereby improving the yield and reliability of implantation. This method is suitable for fiber optic implantation in the manufacturing process of full-size stacked lithium-ion batteries.

[0067] Verification Example 1: Performance evaluation of fiber optic monitoring.

[0068] This validation example aims to conduct a comprehensive performance evaluation of a pre-defined sinusoidal fiber optic implantation layout scheme. For example... Figure 5 As shown, the evaluation object is a [size] with a width of [width]. W = 50 mm, height H A rectangular monitoring area of ​​100 mm was first discretized into a 10×20 grid, and monitoring nodes to be evaluated were set at the vertices of all cells, for a total of N=231. The theoretical fiber optic implantation path C to be evaluated was set as a sine curve, the mathematical expression of which is: x ( y ) = 25 - 25sin(0.1 y ), where y varies from 0 to 100 mm. Before starting the calculation, the parameters of the evaluation model must be given, including the feature monitoring radius. r 0 = 4 mm, attenuation coefficient k=1, and the exponential penalty coefficient used for length penalty. β = 0.1.

[0069] In this verification example, the total arc length of the S-curve is calculated by numerically integrating the derivative of the path function. L C It is approximately 198.05 mm. Subsequently, based on this total length and the sensor's spatial resolution (Δ... s =1.28 mm), and using an algorithm that steps along the arc length, a set S of actual sensor measurement points containing 510 discrete points is generated along the theoretical path. Furthermore, for all 231 grid nodes, the model calculates the shortest Euclidean distance from each node to the 510 discrete measurement points in set S. r ( p This shortest distance was then substituted into the satisfaction monitoring function. S ( r )=1 / (1+e k(r-r0) The monitoring satisfaction score for each node is obtained by using the data from the monitoring data of the node. The calculation results for each node are shown in Table 1.

[0070] Table 1 Fiber Optic Implantation Path x ( y ) = 25 - 25sin(0.1 y The corresponding node monitoring satisfaction level; .

[0071] After obtaining the satisfaction scores of all 231 nodes, the spatial coverage index of this scheme can be obtained by calculating their arithmetic mean. I cov It is approximately 0.273. Meanwhile, to avoid excessively pursuing spatial coverage index and using excessively long fiber lengths, thus affecting cost, a multiplication penalty factor is introduced. P ( L C ) = e -β(LC / Lchar) The total length of the optical fiber in this verification example was calculated. L C = 198.05 mm, region feature length L char = 111.80mm, calculated P ( L C The spatial coverage index is calculated to be 0.8377. Finally, the comprehensive performance index of this scheme is obtained by multiplying the spatial coverage index by the multiplication penalty factor. Q = I cov × P ( L C= 0.229.

[0072] To further verify the effectiveness and sensitivity of the proposed comprehensive performance evaluation index Q, this verification example selects four sinusoidal curves with sequentially increasing spatial frequencies (i.e., curvature) as the theoretical fiber implantation paths to be evaluated, labeled as scheme (a), scheme (b), scheme (c), and scheme (d), respectively. The evaluation process and results can be obtained through... Figures 6-9 Present it visually. Figures 6-9 In the diagram, the red lines represent the fiber optic implantation path, the gray dashed lines form a 10×20 grid, and the black solid lines define a 50 mm × 100 mm battery area.

[0073] Specifically, Figure 6 The function corresponding to the fiber optic implantation path is: x ( y ) = 25 - 25sin(0.1 y Spatial distribution cloud map of node monitoring satisfaction. Figure 7 The function corresponding to the fiber optic implantation path is: x ( y ) = 25 - 25sin(0.3 y Spatial distribution cloud map of node monitoring satisfaction. Figure 8 The function corresponding to the fiber optic implantation path is: x ( y ) = 25 - 25sin(0.5 y Spatial distribution cloud map of node monitoring satisfaction. Figure 9 The function corresponding to the fiber optic implantation path is: x ( y ) = 25 - 25sin(0.7 y The spatial distribution cloud map of the node monitoring satisfaction is shown. The 231 monitoring nodes are assigned different colors from blue to yellow based on their monitoring satisfaction, visually displaying the spatial distribution of monitoring satisfaction at different nodes.

[0074] like Figures 6-9 As shown, from scheme (a) to scheme (d), as the complexity and total length of the fiber optic installation path increase, the overall color of the node gradually warms up, indicating an improvement in monitoring satisfaction. This intuitively corresponds to the spatial coverage index. I cov A sustained increase from 0.2730 to 0.8815. However, the final overall performance index... Q The value exhibits a non-monotonic change, first increasing and then decreasing, and reaches a maximum value of 0.3917 at scheme (b).

[0075] Furthermore, the core performance indicators of each scheme calculated by the model are shown in Table 2. It can be seen that from scheme (a) to scheme (b)...I cov Achieving a significant increase of over 120% yields positive benefits far outweighing the penalty effect caused by the increased length, resulting in a substantial increase in the Q value to 0.3917. This significant improvement indicates that the increased cost of fiber optic laying complexity at this stage leads to a high performance conversion efficiency. However, in subsequent stages, the diminishing marginal returns become very apparent. (From scheme (b) to scheme (c)...) I cov The increase slowed to approximately 29%, at which point the improvement in coverage was insufficient to fully offset the enhancing effect of the length penalty, causing the Q value to drop from its peak to 0.3823. This trend was even more pronounced in scheme (d), where... L C It has reached 1127.91 mm, and I cov The improvement compared to scheme (c) is very limited, indicating that the monitoring coverage is close to saturation. Therefore, its small gain cannot compensate for the penalty effect caused by the increase in fiber length, causing the Q value to drop to 0.3214.

[0076] In summary, this verification example, through a systematic evaluation and quantitative comparison of a set of specific schemes, fully demonstrates the implementation process and effectiveness of the evaluation method. It proves that this method can serve as an objective and accurate decision-making tool, scientifically selecting, through a comprehensive performance index Q, the design shown in scheme (b) that achieves the optimal balance between coverage performance and economic cost from multiple candidate schemes, providing important technical support for the optimization of fiber optic sensor systems for lithium-ion batteries.

[0077] Table 2. Comparison of core performance indicators of four fiber optic implantation and deployment schemes. .

[0078] Verification Example 2: Fabrication of a 10 Ah stacked lithium-ion battery with a built-in S-type fiber optic sensor.

[0079] This validation example aims to illustrate the specific application of the non-destructive implantation method for fiber optic sensors. The goal is to fabricate a stacked lithium-ion battery with a nominal capacity of 10 Ah, dimensions of 85 mm × 120 mm × 12 mm, and an internally embedded S-shaped fiber optic sensor.

[0080] 1. Preparation of negative electrode by single-sided coating.

[0081] Artificial graphite was selected as the negative electrode active material, and 8μm thick copper foil was used as the current collector. Two single-sided coated negative electrode sheets matching the size of a 10Ah battery cell were prepared by single-sided coating using a blade coating process. To accommodate the 10Ah capacity design, the dry film thickness after coating was precisely controlled at 70μm.

[0082] 2. Base fabrication and integration with fiber optic sensor.

[0083] A 3D printing method was used to fabricate the base for supporting the optical fiber. The base material was ABS (acrylonitrile-butadiene-styrene copolymer) plastic. A fused deposition modeling (FDM) 3D printer was used to print the base with pre-defined S-shaped microgrooves at a layer height of 0.1 mm and a nozzle diameter of 0.2 mm. The microgroove depth was set to 0.9 mm to match the optical fiber dimensions.

[0084] 3. Fiber preparation and splicing.

[0085] A distributed optical fiber with a diameter of 0.87 mm and a perfluoroalkoxy tube was selected and precisely embedded into the microgroove of the printed ABS substrate.

[0086] 4. Base surface treatment and fiber fixation.

[0087] To enhance the long-term chemical stability of the substrate in the electrolyte environment, the printed ABS substrate underwent polishing and plasma cleaning, followed by vacuum chemical vapor deposition of a 5μm thick parylene coating. This coating is dense, insulating, and corrosion-resistant, effectively protecting the ABS substrate. After treatment, the optical fiber was locally fixed using a low-temperature epoxy adhesive and cured in an oven at 70°C for 30 minutes.

[0088] 5. Composite negative electrode assembly.

[0089] This step is performed in an ultra-clean, dry room with an ISO 5 cleanliness level, a temperature of 22°C, and a relative humidity below 25%. The uncoated copper foil sides of the two single-sided negative electrode sheets are aligned with both sides of the ABS substrate embedded with optical fibers. A layer of silver-based conductive adhesive with a thickness of 8μm is uniformly applied to the bonding surface. Using precision pressing equipment, the electrodes are pressed together for 12 seconds under a constant pressure of 0.8MPa. Subsequently, they are heat-cured at 70°C for 25 minutes to ensure complete curing of the conductive adhesive and achievement of the designed bonding strength. After assembly, the surface flatness is checked using a high-precision 3D profilometer to ensure the error is within 10μm.

[0090] 6. Cell stacking.

[0091] The composite negative electrode is treated as a single negative electrode unit and alternately stacked with lithium iron phosphate (LFP) positive electrode sheets and composite separators using conventional stacking processes to form a complete 10 Ah battery cell. The entire stacking process is carried out under a constant voltage of 1.0 MPa.

[0092] 7. Battery packaging.

[0093] (1) Pre-drilled openings: The S-type optical fiber has two leads, one in and one out. Based on its lead-out position on the base, two micro openings with matching spacing and a diameter of 0.9 mm are pre-drilled at the end of the aluminum-plastic film away from the electrode tab.

[0094] (2) Top and side sealing: After the battery cell is placed into the aluminum-plastic film bag, the top sealing area is first sealed at 180°C and 0.5MPa. Then, the side sealing area is heat sealed at 170°C and 0.6MPa.

[0095] (3) Electrolyte injection and sealing: Pass both ends of the optical fiber through the two reserved openings and apply silicone sealant around the inside of the openings. After the electrolyte injection is completed, seal the sealing area at 160℃ and 0.4MPa.

[0096] (4) Secondary sealing and enhanced sealing of openings: After the battery is formed and vented, a final secondary sealing is performed. Subsequently, a secondary enhanced sealing is performed on the two optical fiber lead-out openings. A high-precision dispensing process is used to fill and cover the inner and outer sides of the openings with an epoxy resin sealant that is resistant to electrolyte corrosion, and the openings are heat-cured under a local pressure of 0.2 MPa to form a reliable sealing structure.

[0097] Example 3 This embodiment provides a fiber optic sensor implantation evaluation system, including: The distance assessment module is configured to calculate the shortest distance from the fiber optic implantation path to each monitoring node within the monitoring area. The satisfaction assessment module is configured to determine monitoring satisfaction based on the shortest distance to each monitoring node; The performance evaluation module is configured to use the average monitoring satisfaction of all monitoring nodes in the area to be monitored as the spatial coverage index, and combine it with a multiplicative penalty factor that decreases exponentially with the total length of the optical fiber to determine the monitoring performance score of the optical fiber implantation path to be evaluated, and to determine the optimal optical fiber implantation scheme based on this score.

[0098] It should be noted that the above modules correspond to the steps described in Embodiment 1, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in Embodiment 1. It should also be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer-executable instructions.

[0099] In further embodiments, the following is also provided: A lithium-ion battery comprising: prepared by the non-destructive implantation method of the fiber optic sensor described in Example 2.

[0100] An electronic device includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, perform the method described in Embodiment 1. For brevity, further details are omitted here.

[0101] It should be understood that in this embodiment, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0102] Memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of memory may also include non-volatile random access memory. For example, memory may also store information about the device type.

[0103] A computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in Embodiment 1.

[0104] The method in Example 1 can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not provided here.

[0105] A computer program product includes a computer program that, when executed by a processor, implements the method described in Embodiment 1.

[0106] The present invention also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, which execute in a device on a target real or virtual processor to perform the processes / methods described above. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of program modules can be combined or divided among program modules as needed. The machine-executable instructions for the program modules can execute within a local or distributed device. In a distributed device, the program modules can reside in both local and remote storage media.

[0107] The computer program code used to implement the methods of the present invention may be written in one or more programming languages. This computer program code may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the computer or other programmable data processing device, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a computer, partially on a computer, as a stand-alone software package, partially on a computer and partially on a remote computer, or entirely on a remote computer or server.

[0108] In the context of this invention, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, and the like. Examples of signals may include electrical, optical, radio, sound, or other forms of propagation signals, such as carrier waves, infrared signals, etc.

[0109] Those skilled in the art will recognize that the units and algorithm steps described in connection with the various examples of this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. 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 implementation should not be considered beyond the scope of this invention.

[0110] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for evaluating the implantation of fiber optic sensors, characterized in that, include: For each monitoring node within the monitoring area, calculate the shortest distance from the fiber optic cable implantation path to be evaluated. The monitoring satisfaction level is determined based on the shortest distance at each monitoring node. The average monitoring satisfaction of all monitoring nodes in the area to be monitored is used as the spatial coverage index. Combined with the multiplicative penalty factor that decreases exponentially with the total length of the optical fiber, the monitoring performance score of the optical fiber implantation path to be evaluated is determined, and the optimal optical fiber implantation scheme is determined accordingly.

2. The fiber optic sensor implantation evaluation method as described in claim 1, characterized in that, Monitoring satisfaction S ( r )for: ; In the formula, r 0 represents the feature monitoring radius, signifying the critical distance between satisfaction and dissatisfaction; k The attenuation coefficient; r The shortest distance between each monitoring node and the fiber optic implantation path to be evaluated.

3. The fiber optic sensor implantation evaluation method as described in claim 1, characterized in that, Multiplication penalty factor P ( L C )for: In the formula, L C This represents the total length of the current fiber optic installation and deployment scheme; β The coefficient is the exponential penalty coefficient. L char The characteristic length; The monitoring performance score is obtained by multiplying the spatial coverage index and the multiplication penalty factor.

4. A method for non-destructive implantation of a fiber optic sensor, characterized in that, include: A single-sided coated negative electrode sheet is prepared by coating an active material layer on one side of the current collector with the negative electrode material. According to the optimal fiber optic implantation arrangement scheme, microgrooves are prefabricated on the base surface, and the groove depth is matched with the diameter of the fiber optic sensor, so as to embed the fiber optic sensor into the microgrooves. The optimal fiber optic implantation layout scheme is obtained by using the fiber optic sensor implantation evaluation method according to any one of claims 1-3; Assemble a single-sided coated negative electrode sheet and a base for embedding an optical fiber sensor to form a composite negative electrode; The composite negative electrode, separator, and positive electrode are stacked sequentially according to the stacking process before battery encapsulation.

5. The method for non-destructive implantation of a fiber optic sensor as described in claim 4, characterized in that, A substrate with microgrooves is prepared using microfabrication or 3D printing methods. Two single-sided coated negative electrode sheets are assembled with the substrate containing an embedded fiber optic sensor to form a composite negative electrode structure. The structure of the composite negative electrode is: negative electrode active material layer - current collector - substrate - current collector - negative electrode active material layer.

6. The non-destructive implantation method for a fiber optic sensor as described in claim 4, characterized in that, The battery encapsulation process includes: according to the fiber optic sensor lead-out point position in the fiber optic implantation arrangement scheme, pre-fabricating one or more openings on the bottom side of the battery aluminum-plastic film, with the opening diameter matching the fiber optic diameter, and the opening position corresponding to the fiber optic lead-out end on the composite negative electrode base to lead out the fiber optic connector, while planning in the non-core active area of ​​the cell.

7. The non-destructive implantation method for a fiber optic sensor as described in claim 6, characterized in that, The battery packaging process also includes: Top sealing area encapsulation: Heat sealing technology is used to seal the top sealing area by controlling the heat sealing temperature and pressure, ensuring the bonding between the electrode end and the battery aluminum-plastic film; and the optical fiber lead-out path avoids the top sealing area and extends along the edge of the cell to the bottom opening; Side sealing: The aluminum-plastic film on both sides of the battery is sealed by heat sealing equipment, which controls the heat sealing temperature and pressure.

8. The method for non-destructive implantation of a fiber optic sensor as described in claim 7, characterized in that, The battery packaging process also includes: One-seal encapsulation: First, the optical fiber is passed through the reserved opening. At the end away from the tab, i.e. the one-seal area, a preliminary seal is performed, leaving an injection port. At the same time, a ring of sealant is pre-applied around the opening for preliminary isolation. Then, electrolyte is injected through the injection port to complete the preliminary sealing of the one-seal area. Secondary sealing area and opening sealing: After the battery has undergone formation and venting processes, the final vacuum heat sealing is performed to complete the secondary sealing area encapsulation and ensure that the battery cell is completely sealed.

9. A fiber optic sensor implantation evaluation system, characterized in that, include: The distance assessment module is configured to calculate the shortest distance from the fiber optic implantation path to each monitoring node within the monitoring area. The satisfaction assessment module is configured to determine monitoring satisfaction based on the shortest distance to each monitoring node; The performance evaluation module is configured to use the average monitoring satisfaction of all monitoring nodes in the area to be monitored as the spatial coverage index, and combine it with a multiplicative penalty factor that decreases exponentially with the total length of the optical fiber to determine the monitoring performance score of the optical fiber implantation path to be evaluated, and to determine the optimal optical fiber implantation scheme based on this score.

10. A lithium-ion battery, characterized in that, include: The fiber optic sensor was prepared using the non-destructive implantation method according to any one of claims 4-8.

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