Fiber optic sensor implant evaluation, non-invasive implantation method and system

Abstract

The application discloses a kind of optical fiber sensor implantation evaluation, nondestructive implantation method and system, it is related to lithium ion battery monitoring and manufacturing process technical field, including: to each monitoring node in the region to be monitored, the shortest distance of the optical fiber implantation arrangement path to be evaluated is calculated;According to the shortest distance of each monitoring node, determine monitoring satisfaction;With the average value of the monitoring satisfaction of all monitoring nodes in the region to be monitored as spatial coverage index, combined with the multiplication penalty factor attenuated with the total length of optical fiber, determine the monitoring performance score of the optical fiber implantation arrangement path to be evaluated, to determine the optimal optical fiber implantation arrangement scheme, then by improving negative electrode structure and optimizing manufacturing process, realize the safe integration of optical fiber sensor in the core area of battery cell without affecting battery performance, solve the technical problems that optical fiber sensor layout design lacks scientific basis and implantation process is easy to damage battery cell in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery monitoring and manufacturing process, and particularly relates to a fiber sensor implantation evaluation, non-destructive implantation method and system. BACKGROUND

[0002] With the rapid development of new energy vehicles and large-scale energy storage industries, the safety, performance and service life of lithium ion batteries as the core energy storage unit have become the key factors determining the development of the industry. Real-time and accurate monitoring of the internal state of the battery, especially the temperature and strain, is the fundamental technical means to improve the efficiency of the battery management system (BMS), early warning of thermal runaway, and prolonging the service life of the battery. In this context, fiber optic sensors have shown great application potential in the field of lithium ion battery internal monitoring due to their small size (up to microns), resistance to electromagnetic interference, high sensitivity, and ability to achieve distributed measurement.

[0003] Currently, research on the application of fiber optic sensors in lithium ion battery internal state monitoring has made some progress. For example, in cylindrical lithium ion batteries with a central hole, existing technologies have attempted to implant fiber optic sensors in the winding core and successfully achieved internal temperature and strain monitoring. However, as one of the mainstream technical routes in the power battery and energy storage fields, the laminated (soft pack) lithium ion battery is composed of highly compacted positive and negative electrode and separator sheets, with no obvious inherent voids, making the internal implantation of fiber optic sensors a serious technical challenge. To avoid this problem, some existing technologies propose placing fiber optic sensors in the gap between the cell stack and the aluminum plastic film shell. Although this scheme can achieve implantation, the sensor does not truly enter the active area of the cell, and cannot directly and accurately obtain the temperature and strain signals at the core position of the cell. With the development of battery technology towards high capacity and high rate, the uneven distribution of heat accumulation and mechanical stress inside the single cell (e.g., exceeding 100 Ah) during operation becomes increasingly prominent, with a temperature difference of more than 10℃ between the core area and the surface, and a significant stress gradient. Therefore, the limitations of this surface monitoring method are increasingly evident, making it difficult to meet the needs of precise and safe management of the next generation of high-performance batteries.

[0004] In summary, although the importance of in-situ fiber monitoring has been recognized in the industry, its application in laminated lithium ion batteries still faces a series of technical bottlenecks that need to be addressed, which hinder the realization of reliable and efficient in-situ precise monitoring systems.

[0005] Firstly, there is a lack of scientific sensor layout design method. How to lay optical fibers in a two-dimensional or three-dimensional space to reduce the cost increase, process complication and potential impact on battery performance caused by the total length of optical fibers as much as possible under the premise of ensuring monitoring coverage and accuracy. The existing technology relies on experience for layout, and lacks quantifiable performance evaluation index to scientifically guide and optimize the design.

[0006] Secondly, there is a lack of mature non-destructive implantation process inside the sensor. If the optical fiber is forcibly implanted between the compact electrode layers, it will inevitably cause local gaps and damage the uniform transport channel of lithium ions, thereby causing the decline of battery electrochemical performance and the reduction of long-term reliability. At the same time, the hot-press sealing step in the battery packaging process is also easy to cause mechanical damage to the delicate optical fiber, affecting the final yield and signal transmission stability. SUMMARY

[0007] In order to solve the above problems, the present application provides a fiber sensor implantation evaluation, non-destructive implantation method and system, which guides the optimal spatial layout of the fiber sensor through comprehensive monitoring performance evaluation index, realizes the safe integration of the fiber sensor in the core area of the battery without affecting the battery performance through the improvement of the negative electrode structure and the optimization of the manufacturing process, and solves the technical problems of lack of scientific basis for fiber sensor layout design and damage to the battery during the implantation process in the prior art.

[0008] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0009] In a first aspect, the present application provides a fiber sensor implantation evaluation method, comprising:

[0010] For each monitoring node in the to-be-monitored area, the shortest distance from the to-be-evaluated fiber implantation layout path is calculated;

[0011] The monitoring satisfaction degree of each monitoring node is determined according to the shortest distance;

[0012] The average value of the monitoring satisfaction degrees of all monitoring nodes in the to-be-monitored area is taken as the spatial coverage index, and the monitoring performance score of the to-be-evaluated fiber implantation layout path is determined in combination with the multiplication penalty factor attenuated with the total length of the optical fiber, and the optimal fiber implantation layout scheme is determined accordingly.

[0013] As an optional implementation, the monitoring satisfaction degree S ( r ) is: ;

[0014] In the formula, r 0 is the characteristic monitoring radius, representing the critical distance between satisfaction and dissatisfaction; k is the attenuation coefficient; rThe shortest distance between each monitoring node and the path of the optical fiber to be evaluated.

[0015] As an alternative embodiment, the multiplication penalty factor P ( L C ) is: ; in which, L C L is the total length of the current optical fiber implantation arrangement scheme; β is an exponential penalty coefficient; L char is a characteristic length;

[0016] The space coverage index and the multiplication penalty factor are multiplied to obtain the monitoring performance score.

[0017] In a second aspect, the present application provides a method for non-destructive implantation of an optical fiber sensor, comprising:

[0018] A single-sided coated negative electrode sheet is prepared by coating an active material layer on one side of the current collector using a negative electrode material;

[0019] A micro groove is pre-prepared on the surface of the base according to the optimal optical fiber implantation arrangement scheme, and the groove depth matches the diameter of the optical fiber sensor, so as to embed the optical fiber sensor in the micro groove; the optimal optical fiber implantation arrangement scheme is obtained by using the optical fiber sensor implantation evaluation method of the first aspect;

[0020] The single-sided coated negative electrode sheet and the base embedded with the optical fiber sensor are assembled to form a composite negative electrode;

[0021] The composite negative electrode, the separator and the positive electrode are sequentially stacked according to the stacking process, and then the battery is packaged.

[0022] As an alternative embodiment, a micro-machining method or a 3D printing method is used to prepare the base with a micro groove; two single-sided coated negative electrode sheets and the base embedded with the optical fiber sensor are assembled to form a composite negative electrode structure, and the structure of the composite negative electrode is negative electrode active material layer-current collector-base-current collector-negative electrode active material layer.

[0023] As an alternative embodiment, the battery packaging process includes: according to the position of the optical fiber sensor lead-out point in the optical fiber implantation arrangement scheme, one or more openings are pre-prepared on the bottom side of the battery aluminum plastic film, the opening diameter matches the diameter of the optical fiber, and the opening position corresponds to the optical fiber lead-out endpoint on the base of the composite negative electrode, so as to lead out the optical fiber joint, while planning in the non-core active area of the battery cell.

[0024] As an alternative embodiment, the battery packaging process further includes:

[0025] Top sealing area packaging: using heat sealing technology, by controlling the heat sealing temperature and pressure, sealing the top sealing area, ensuring the combination of 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 battery cell to the bottom opening;

[0026] Side sealing area packaging: through the heat sealing equipment, by controlling the heat sealing temperature and pressure, sealing the two sides of the battery aluminum plastic film.

[0027] As an alternative embodiment, the battery packaging process further comprises:

[0028] One sealing area packaging: first, the optical fiber is pulled out from the reserved opening, and the preliminary sealing is carried out at the end away from the tab, that is, one sealing area, and the liquid injection port is left; at the same time, a circle of sealant is coated around the opening for preliminary isolation, and then the electrolyte is injected through the liquid injection port to complete the preliminary sealing of one sealing area;

[0029] Two sealing area and opening sealing: after the battery is subjected to formation and exhaust process, the final vacuum heat sealing is carried out to complete the two sealing area packaging, ensuring that the battery monomer is completely sealed.

[0030] In a third aspect, the present application provides a fiber optic sensor implantation evaluation system, comprising:

[0031] The distance evaluation module is configured to calculate the shortest distance from each monitoring node in the to-be-monitored area to the to-be-evaluated fiber implantation arrangement path;

[0032] The satisfaction evaluation module is configured to determine the monitoring satisfaction according to the shortest distance of each monitoring node;

[0033] The performance evaluation module is configured to take the average value of the monitoring satisfaction of all monitoring nodes in the to-be-monitored area as the spatial coverage index, combine the multiplicative penalty factor attenuated with the total length of the fiber, determine the monitoring performance score of the to-be-evaluated fiber implantation arrangement path, and determine the optimal fiber implantation arrangement scheme.

[0034] In a fourth aspect, the present application provides a lithium ion battery, comprising: prepared by the fiber optic sensor non-destructive implantation method of the second aspect.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] In view of the problem that the fiber implantation arrangement lacks scientific design basis, the application provides a fiber sensor implantation evaluation method, which guides the optimal spatial layout of the fiber sensor through comprehensive monitoring performance evaluation indexes, the indexes combine the spatial coverage index representing coverage with a multiplication penalty factor decaying with the total length index of the fiber, so that scientific evaluation of different fiber implantation arrangement schemes is realized, and a unified and quantitative evaluation index is established for scientifically evaluating the comprehensive performance of any given fiber implantation arrangement scheme.

[0037] After the optimal fiber implantation arrangement is determined, the application solves the problem that the structure of the battery cell is damaged and the lithium ion transport performance is adversely affected in the process of implanting the fiber sensor by improving the negative electrode structure and optimizing the manufacturing process, and provides a fiber sensor lossless implantation method.

[0038] In the fiber sensor lossless implantation method of the application, the packaging process directly punches a hole in the bottom side of the battery aluminum plastic film to lead out the fiber joint, and adopts a secondary reinforced sealing mode, which not only effectively solves the sealing problem of the leading-out point, but also shortens the redundant path of the fiber in the packaging body, reduces the potential signal loss and packaging complexity, and improves the yield and reliability of the implantation.

[0039] The advantages of the additional aspects of the application will be partially given in the following description, partially become obvious from the following description, or be learned through the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only show the embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0041] Figure 1 The overall flowchart of the fiber sensor implantation evaluation and lossless implantation provided by the application is shown in the following figure:

[0042] Figure 2 The flow chart of the fiber sensor implantation evaluation method provided for the embodiment 1 of the present application is shown in FIG. 1;

[0043] Figure 3 The schematic diagram of the monitoring area grid node provided for the embodiment 1 of the present application is shown in FIG. 2;

[0044] Figure 4 The flow chart of the fiber sensor non-destructive implantation method provided for the embodiment 2 of the present application is shown in FIG. 3;

[0045] Figure 5 The schematic diagram of the battery monitoring area grid node provided for the verification example 1 of the present application is shown in FIG. 4;

[0046] Figure 6 The node monitoring satisfaction degree spatial distribution cloud diagram corresponding to the fiber implantation arrangement path scheme (a) provided for the verification example 1 of the present application is shown in FIG. 5;

[0047] Figure 7 The node monitoring satisfaction degree spatial distribution cloud diagram corresponding to the fiber implantation arrangement path scheme (b) provided for the verification example 1 of the present application is shown in FIG. 6;

[0048] Figure 8 The node monitoring satisfaction degree spatial distribution cloud diagram corresponding to the fiber implantation arrangement path scheme (c) provided for the verification example 1 of the present application is shown in FIG. 7;

[0049] Figure 9 The node monitoring satisfaction degree spatial distribution cloud diagram corresponding to the fiber implantation arrangement path scheme (d) provided for the verification example 1 of the present application is shown in FIG. 8. DETAILED DESCRIPTION

[0050] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0051] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present application. Unless otherwise defined, 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 application belongs.

[0052] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0053] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0054] Example 1

[0055] 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.

[0056] Combination Figures 1-2 As shown, it specifically includes:

[0057] For each monitoring node within the monitoring area, calculate the shortest distance from the fiber optic cable implantation path to be evaluated;

[0058] The monitoring satisfaction level is determined based on the shortest distance at each monitoring node.

[0059] 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.

[0060] Specifically:

[0061] like Figure 3 As shown, to facilitate quantitative calculations, the continuous monitoring region Ω (such as a plane of a battery) is spatially discretized.

[0062] 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.

[0063] 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.

[0064] Assume the fiber optic implantation path is a continuous curve. CThis means that for any monitoring node p Calculate the fiber curve C Euclidean shortest distance r :

[0065] (1);

[0066] in, q It is a curve C Any point on it.

[0067] 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.

[0068] (2);

[0069] 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.

[0070] 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.

[0071] For a given fiber optic implantation path, the curve C and grid P Spatial coverage index I cov The calculation is as follows:

[0072] (3);

[0073] 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.

[0074] Furthermore, to avoid blindly pursuing the use of infinitely long or overly complex optical fibers... I covapproaches 1, a penalty on the total length of the optical fiber is introduced. That is, a multiplicative penalty factor is defined which decays exponentially with the total length of the optical fiber P L C , whose value range is (0, 1], L C =0 is 1, and approaches 0 as L C increases.

[0075] (4).

[0076] wherein, L C is the total length of the current optical fiber implantation arrangement; β is the exponential penalty coefficient, which is a dimensionless parameter, used to adjust the severity of the length penalty; L char is the characteristic length (e.g. the diagonal length of the battery), used to normalize L C .

[0077] Finally, the spatial coverage index and the multiplicative penalty factor are combined to obtain the final monitoring performance score Q ;

[0078] (5).

[0079] The Q value as a normalized comprehensive score can scientifically and objectively evaluate the pros and cons of different optical fiber implantation arrangement, thereby providing decisive data support for realizing the optimal sensor spatial layout.

[0080] Embodiment 2

[0081] After determining the optimal optical fiber implantation arrangement, this embodiment solves the problem of damaging the structure of the battery and adversely affecting the lithium ion transport performance during the optical fiber implantation process by improving the negative electrode structure and optimizing the manufacturing process, and provides a non-destructive implantation method of optical fiber sensor.

[0082] In combination with the embodiments shown in Figure 1 and Figure 4 , the specific steps include:

[0083] The active material layer is coated on one side of the current collector using the negative electrode material to obtain a single-sided coated negative electrode sheet;

[0084] According to the optimal optical fiber implantation arrangement, a micro groove is prefabricated on the surface of the base, and the groove depth matches the diameter of the optical fiber sensor, so that the optical fiber sensor is embedded in the micro groove;

[0085] The single-sided coated negative electrode sheet and the base embedded with the optical fiber sensor are assembled to form a composite negative electrode.​

[0086] The composite negative electrode, the separator and the positive electrode are stacked in sequence according to a lamination process, and then the battery is packaged.

[0087] The optimal fiber implantation arrangement is obtained by using the fiber sensor implantation evaluation method of embodiment 1.

[0088] Specifically:

[0089] (1) Preparation of single-sided coated negative electrode sheet.

[0090] A single-sided coated active material layer is coated on a copper foil current collector using a negative electrode material such as graphite, thereby preparing two single-sided coated negative electrode sheets.

[0091] Each negative electrode structure is a negative electrode active material layer-current collector, and the coating thickness is controlled to be 50-150 μm to ensure the uniformity and electrochemical performance stability of the subsequent lamination structure.

[0092] (2) Preparation of base and embedding of fiber sensor.

[0093] The base is designed according to the fiber implantation arrangement path and diameter. The base is preferably made of a high 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.

[0094] The base can be prepared and the fiber sensor can be embedded by one of the following two methods.

[0095] Microfabrication method: A microgroove is pre-fabricated on the surface of the base by microfabrication techniques such as laser engraving and precision scribing. The groove depth matches the diameter of the fiber sensor (usually 0.1-1 mm), and the groove width error is controlled within ±50 μm. After processing, the surface residues are removed by plasma cleaning to improve the surface affinity. The fiber sensor is embedded in the microgroove and fixed using a low-temperature curing adhesive (such as an epoxy-based adhesive, with a curing temperature below 80°C) to ensure that the fiber sensor is tightly attached to the base and does not protrude from the surface of the base.

[0096] 3D printing method: using high-precision additive manufacturing technology (such as Fused Deposition Modeling (FDM) suitable for thermoplastic plastics such as ABS, or StereoLithography Apparatus (SLA) / Digital Light Processing (DLP) suitable for photosensitive resin), print the base with pre-prepared microgrooves. The printing parameters are set according to the selected technology to ensure that the microgroove depth is accurately matched with the diameter of the optical fiber sensor, the groove width error is controlled within ±50μm, and the base surface is flat and the structure is complete. After printing, plasma cleaning, optical fiber embedding and low temperature curing and fixing are also carried out.

[0097] (3) Composite negative electrode assembly.

[0098] Two single-sided coated negative electrode sheets are assembled with the base embedded with the optical fiber sensor to form a composite negative electrode structure, i.e. negative active material layer - current collector - base - current collector - negative active material layer.

[0099] During assembly, the adhesion of the negative electrode current collector to the base uses high-performance conductive adhesive (such as silver-based or carbon-based conductive adhesive, conductivity ≥10 4 S / m), which is uniformly coated on the contact surface of the current collector and the base, with a coating thickness of 5-20μm. The conductive adhesive curing temperature is controlled at 60-100℃, and the curing time is 10-30 minutes to ensure the bonding strength (shear strength ≥5MPa).

[0100] A precision pressing technique is used with a constant pressure pressing device to control the pressing pressure at 0.3-1.5MPa and the pressing time at 5-15 seconds to ensure that there are no bubbles or pores between the layers. During the pressing process, the flatness of the pressing surface (error ≤10μm) needs to be monitored to avoid displacement of the optical fiber sensor or deformation of the base due to uneven pressure.

[0101] Assembly is carried out in a dust-free workshop (cleanliness level ≥ISO5) with an environmental temperature controlled at 20-25℃ and a relative humidity less than 30% to prevent dust or moisture from contaminating the performance of the conductive adhesive or the structure of the electrode. After assembly, the internal structure of the composite negative electrode is checked by ultrasonic imaging or X-ray detection technology to confirm that there are no bubbles, cracks or optical fiber sensor displacement.

[0102] (4) Cell lamination.

[0103] The composite negative electrode, separator and positive electrode are sequentially stacked according to the conventional lamination process 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 to ensure that the optical fiber sensor in the composite negative electrode does not displace or break, while maintaining the tightness and consistency of the cell structure.

[0104] (5) Battery packaging.

[0105] Open hole reservation: According to the position of the fiber sensor's exit point in the fiber implantation arrangement scheme, one or more micro-holes are pre-made on the bottom side of the aluminum-plastic film (away from the tab). The hole position corresponds to the exit point of the fiber on the composite negative base, while planning in the non-core active area of the battery, ensuring that it does not affect the structural strength of the battery. The hole diameter is determined according to the fiber diameter (about 0.1-1 mm).

[0106] Top seal area packaging: Using heat sealing technology, the heat sealing temperature is controlled at 160-200℃, the pressure is 0.2-0.8MPa, and the top sealing area is sealed to ensure the close combination of the electrode end and the aluminum-plastic film. The fiber exit path is designed to avoid the top sealing area and extend to the bottom hole along the edge of the battery to avoid pressure.

[0107] Side seal area packaging: The aluminum-plastic film on both sides is sealed by a heat sealing device, with a heat sealing temperature of 150-190℃ and a pressure of 0.3-1.0MPa.

[0108] One seal area packaging: Preliminary sealing is performed at the end away from the tab (i.e. one seal area), and a liquid injection port is left. Before this step, the fiber is pulled out of the pre-made hole. To prevent leakage during subsequent electrolyte injection, a circle of flexible sealant (such as silicone glue) is pre-applied around the hole for preliminary isolation. Then, electrolyte (such as carbonate electrolyte) is injected, and preliminary heat sealing of the one seal area is completed, with a temperature control of 140-180℃ and a pressure of 0.2-0.6MPa.

[0109] Two seal area and hole sealing: After the battery has undergone processes such as formation and exhaust, the final vacuum heat sealing is performed to complete the two seal area packaging, ensuring that the battery monomer is completely sealed, with a temperature of 150-190℃ and a pressure of 0.3-0.8MPa.

[0110] In this embodiment, the final sealing of the fiber exit hole is a key step. This step uses high-precision dispensing technology, using high-molecular sealing materials (such as electrolyte-resistant epoxy resin or silicone glue) to fill and coat the inside and outside of the hole, and then heat curing or UV curing under a specific pressure (0.1-0.5MPa). This step aims to form a long-term, reliable, and excellent airtight and mechanically strong sealing structure, ensuring the safety of the battery and the long-term stability of the fiber signal transmission. Finally, the exit fiber end is connected to the external monitoring system.

[0111] 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.

[0112] Verification Example 1: Performance evaluation of fiber optic monitoring.

[0113] 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.

[0114] 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+ek(r-r0) ) to obtain the monitoring satisfaction score of the node. The calculation results of each node are shown in Table 1.

[0115] Table 1 Fiber implantation arrangement path x y = 25 - 25sin(0.1 y ) corresponding to the monitoring satisfaction of each node;

[0116] .

[0117] After obtaining the satisfaction scores of all 231 nodes, the spatial coverage index of the scheme can be obtained by calculating the arithmetic mean thereof I cov about 0.273. At the same time, in order to avoid excessive pursuit of the spatial coverage index and use of too long fiber length to affect the cost, a multiplication penalty factor P ( L C ) = e -β(LC / Lchar) is introduced. It is calculated that the total length of the fiber in the present verification example L C = 198.05 mm, the area characteristic length L char = 111.80 mm, and P ( L C ) = 0.8377. Finally, the spatial coverage index is multiplied by the multiplication penalty factor to obtain the comprehensive performance index of the scheme Q = I cov × P ( L C ) = 0.229.

[0118] To further verify the effectiveness and sensitivity of the proposed comprehensive performance evaluation index Q, four sinusoidal curves with increasing spatial frequencies (i.e. bending degrees) are selected as the theoretical fiber implantation arrangement paths to be evaluated, which are marked as scheme (a), scheme (b), scheme (c) and scheme (d) in turn. The evaluation process and results can be visually presented by Figures 6-9 . Figures 6-9 In the figure, the red line is the fiber implantation arrangement path, the gray dashed line constitutes a 10x20 grid, and the black solid line frame defines a 50 mm x 100 mm battery area.

[0119] Specifically, Figure 6 is the fiber implantation arrangement path, and the corresponding function is x ( y )=25-25sin(0.1 y ​node monitoring satisfaction spatial distribution cloud map of Figure 7 is the path corresponding function of fiber implantation arrangement x ( y )=25-25sin(0.3 y ) node monitoring satisfaction spatial distribution cloud map, Figure 8 is the path corresponding function of fiber implantation arrangement x ( y )=25-25sin(0.5 y ) node monitoring satisfaction spatial distribution cloud map, Figure 9 is the path corresponding function of fiber implantation arrangement x ( y )=25-25sin(0.7 y ) node monitoring satisfaction spatial distribution cloud map. 231 monitoring nodes are endowed with different colors from blue to yellow according to monitoring satisfaction, which intuitively shows the spatial distribution of different node monitoring satisfaction.

[0120] As shown in Figures 6-9 , from scheme (a) to scheme (d), with the increase of fiber implantation arrangement path complexity and total length, the overall color of the node gradually warms up, indicating the improvement of its monitoring satisfaction. Intuitively corresponding to the spatial coverage index I cov continuously grows from 0.2730 to 0.8815. However, the final comprehensive performance index Q value presents a non-monotonic change of first increasing and then decreasing, and reaches the maximum value of 0.3917 at scheme (b).

[0121] In addition, 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 achieves a significant growth of more than 120%, and the positive benefit is much greater than the penalty effect caused by the increase in length, so the Q value is greatly improved to 0.3917. This significant improvement shows that the cost of increasing the fiber laying complexity at this stage brings higher performance conversion efficiency. However, in the subsequent stage, the marginal benefit decreases obviously. From scheme (b) to scheme (c), I cov the increase slows down to about 29%, at this time, the improvement of coverage is not enough to completely offset the enhanced effect of length penalty, resulting in the Q value decreasing from the peak to 0.3823. This trend is more obvious in scheme (d), its L C has reached 1127.91 mm, while I covThe promotion compared to scheme (c) is very limited, indicating that the monitoring coverage is close to saturation. Therefore, its small gain cannot make up for the penalty effect caused by the increase in fiber length, making the Q value drop to 0.3214.

[0122] In summary, the present validation example, through the systematic evaluation and quantitative comparison of a group 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 filtering out the design as 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 lithium-ion battery optical fiber sensor systems.

[0123] Table 2 Comparison of core performance indicators of four fiber implantation arrangement schemes;

[0124] .

[0125] Validation Example 2: Preparation of a 10 Ah laminated lithium-ion battery with an embedded S-shaped optical fiber sensor.

[0126] The present validation example aims to detail the specific application of the optical fiber sensor non-destructive implantation method. The goal is to prepare a method for a laminated lithium-ion battery with a nominal capacity of 10 Ah, an external size of 85 mm x 120 mm x 12 mm, and an embedded S-shaped optical fiber sensor.

[0127] 1. Single-sided coating of negative electrode preparation.

[0128] Artificial graphite was selected as the negative active material, and an 8 μm thick copper foil was used as the current collector. Single-sided coating was performed by doctor blade coating to prepare two single-sided coated negative electrode sheets matching the size of the 10 Ah cell. To accommodate the 10 Ah capacity design, the dry film thickness after coating was precisely controlled at 70 μm.

[0129] 2. Preparation of base and embedding of optical fiber sensor.

[0130] A 3D printing method was selected to prepare the base for carrying the optical fiber. ABS (acrylonitrile-butadiene-styrene copolymer) plastic was chosen as the base material. A fused deposition modeling 3D printing device was used to print the base with a preset S-shaped micro groove, with a layer height of 0.1 mm and a nozzle diameter of 0.2 mm. The micro groove depth was set to 0.9 mm to match the fiber size.

[0131] 3. Fiber preparation and embedding.

[0132] A distributed optical fiber with a diameter of 0.87 mm and a perfluoroalkoxy tube was selected and precisely embedded in the micro groove of the printed ABS base.

[0133] 4. Base surface treatment and fiber fixation.

[0134] To enhance the long-term chemical stability of the base in the electrolyte environment, the printed ABS base is additionally treated with a 5-μm-thick parylene coating by vacuum chemical vapor deposition after polishing and plasma cleaning. The coating is dense, insulating, and corrosion-resistant, effectively protecting the ABS base. After treatment, the optical fiber is partially fixed using a low-temperature epoxy adhesive and cured in an oven at 70°C for 30 minutes.

[0135] 5. Composite negative electrode assembly.

[0136] This step is performed in a super-clean dry room with an ISO 5 cleanliness level, a temperature of 22°C, and a relative humidity of less than 25%. The uncoated copper foil side of two single-sided negative electrode sheets is aligned with the two sides of the ABS base with embedded optical fibers. A layer of 8-μm-thick silver-based conductive adhesive is evenly applied to the bonding surface. A precision pressing device is used to press at a constant pressure of 0.8 MPa for 12 seconds. Subsequently, thermal curing is performed at 70°C for 25 minutes to ensure complete curing of the conductive adhesive and achieve the designed bonding strength. After assembly, the surface flatness is checked by a high-precision three-dimensional profilometer to ensure an error within 10 μm.

[0137] 6. Cell stacking.

[0138] The composite negative electrode is used as a whole negative electrode unit, and is alternately stacked with lithium iron phosphate (LFP) positive electrode sheets and composite separators according to the conventional stacking process to form a complete 10 Ah battery cell. The entire stacking process is performed under a constant pressure of 1.0 MPa.

[0139] 7. Battery packaging.

[0140] (1) Hole reservation: The S-shaped optical fiber has two outgoing ends, one in and one out. According to the outgoing position on the base, two micro-holes with a diameter of 0.9 mm and matching spacing are pre-prepared on the side of the aluminum-plastic film away from the electrode tab.

[0141] (2) Top and side packaging: After the battery cell is placed in the aluminum-plastic film bag, the top sealing area is first packaged at 180°C and 0.5 MPa. Subsequently, the side sealing area is heat-sealed at 170°C and 0.6 MPa.

[0142] (3) Liquid injection and one-seal: The two ends of the optical fiber are pulled out from the two reserved holes, and silicone sealant is applied around the inside of the holes. After completing the electrolyte injection, the one-seal area is packaged at 160°C and 0.4 MPa.

[0143] (4) Two-sealing and hole-strengthening sealing: After the battery is exhausted, the final two-sealing is performed. Subsequently, two optical fiber lead-out holes are subjected to secondary strengthening sealing. A high-precision dispensing process is adopted, and an epoxy resin sealing agent resistant to electrolyte corrosion is used to fill and coat the two sides inside and outside the hole, and heat curing is performed under a local pressure of 0.2 MPa to form a reliable sealing structure.

[0144] Embodiment 3

[0145] The embodiment provides a fiber sensor implantation evaluation system, comprising:

[0146] A distance evaluation module is configured to calculate, for each monitoring node in the to-be-monitored region, a shortest distance to the to-be-evaluated fiber implantation arrangement path;

[0147] A satisfaction evaluation module is configured to determine a monitoring satisfaction degree according to the shortest distance of each monitoring node;

[0148] A performance evaluation module is configured to determine a monitoring performance score of the to-be-evaluated fiber implantation arrangement path by taking an average value of the monitoring satisfaction degrees of all the monitoring nodes in the to-be-monitored region as a spatial coverage index and combining a multiplication penalty factor that attenuates with a total length index of the fiber, and to determine an optimal fiber implantation arrangement scheme according to the monitoring performance score.

[0149] It should be noted that the modules correspond to the steps described in Embodiment 1, and the modules have the same examples and application scenarios as the corresponding steps, but are not limited to the content disclosed in Embodiment 1. It should be noted that the modules as part of the system can be executed in a computer system such as a set of computer executable instructions.

[0150] In more embodiments, there are also provided:

[0151] A lithium ion battery, comprising: being prepared by the fiber sensor nondestructive implantation method described in Embodiment 2.

[0152] An electronic device, comprising a memory and a processor, and computer instructions stored in the memory and running on the processor, when the computer instructions are run by the processor, the method described in Embodiment 1 is completed. For the sake of brevity, it will not be repeated here.

[0153] It should be understood that in the embodiment, the processor can be a central processing unit CPU, and the processor can also be other general-purpose processors, digital signal processors DSPs, application-specific integrated circuits ASICs, ready-to-program gate arrays FPGAs or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0154] The memory can include read-only memory and random access memory, and provide instructions and data to the processor, a portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0155] A computer readable storage medium for storing computer instructions, which are executed by a processor to complete the method described in embodiment 1.

[0156] The method in embodiment 1 can be directly embodied as hardware processor execution completion, or executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0157] A computer program product, comprising a computer program, which is executed by a processor to realize the method described in embodiment 1.

[0158] The present application 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 are executed in devices on the target real or virtual processor to perform the processes / methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functions of the program modules can be combined or divided as desired. Machine executable instructions for program modules can be executed within a local or distributed device. In a distributed device, program modules can be located in local and remote storage media.

[0159] The computer program code for implementing the method of the present application can be written in one or more programming languages. These computer program codes can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, so that the program codes cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented when the computer or other programmable data processing apparatus executes the program codes. The program codes can be executed entirely on the computer, partially on the computer, as a separate software package, partially on the computer and partially on a remote computer, or entirely on a remote computer or server.

[0160] In the context of the present application, the computer program code or related data can be carried by any suitable carrier to enable the 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 can include electrical, optical, radio, sound or other forms of propagated signals, such as carrier waves, infrared signals, and the like.

[0161] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the present embodiment can be realized in electronic hardware or in combination of computer software and electronic hardware. Whether the functions are realized in hardware or software manner depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0162] The above describes the specific embodiments of the present application in conjunction with the accompanying drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A method of non-invasive implantation of an optical fiber sensor, characterized in that, The application relates to a negative electrode sheet and a battery with a fiber sensor. The microgrooves are prefabricated on the surface of the base according to the optimal fiber implantation arrangement scheme, and the groove depth matches the diameter of the fiber sensor so that the fiber sensor is embedded in the microgrooves. The determination process of the optimal fiber implantation arrangement scheme comprises the following steps: For each monitoring node in the to-be-monitored area, the shortest distance to the to-be-evaluated fiber implantation arrangement path is calculated; the monitoring satisfaction degree of each monitoring node is determined according to the shortest distance; the average value of the monitoring satisfaction degrees of all the monitoring nodes in the to-be-monitored area is taken as a spatial coverage index, and a multiplication penalty factor that attenuates with the total length of the fiber is combined to determine the monitoring performance score of the to-be-evaluated fiber implantation arrangement path, and the optimal fiber implantation arrangement scheme is determined according to the monitoring performance score. The spatial coverage index and the multiplication penalty factor are multiplied to obtain the monitoring performance score. Monitoring satisfaction S ( r ) is: ; wherein r 0 is a characteristic monitoring radius, representing the critical distance between satisfaction and dissatisfaction; k is a decay coefficient; r is the shortest distance of each monitoring node from the path of the optical fiber to be evaluated. multiplication penalty factor P ( L C ) is: ; where, L C is the total length of the current fiber implant arrangement; β is an exponential penalty coefficient; L char is a characteristic length; The two single-side coated negative electrode sheets and the base with the embedded fiber sensor are assembled to form a composite negative electrode, and the structure of the composite negative electrode is negative electrode active material layer-current collector-base-current collector-negative electrode active material layer. The composite negative electrode, the separator and the positive electrode are sequentially stacked according to the stacking process, and then the battery is packaged. The base with the microgrooves is prepared by a microprocessing method or a 3D printing method.

2. A method of non-invasive implantation of an optical fiber sensor according to claim 1, characterized in that, The process of the battery packaging comprises the following steps: one or more openings are prefabricated on the bottom side of the battery aluminum plastic film according to the lead-out point position of the fiber sensor in the fiber implantation arrangement scheme, the diameter of the opening matches the diameter of the fiber, the opening position corresponds to the fiber lead-out endpoint on the base of the composite negative electrode, and the fiber joint is led out while the non-core active area of the battery cell is planned.

3. A method of non-invasive implantation of an optical fiber sensor according to claim 1, wherein, The process of the battery packaging further comprises the following steps:

4. A method of non-invasive implantation of an optical fiber sensor according to claim 3, characterized in that, Top sealing area packaging: a heat sealing technology is adopted to seal the top sealing area by controlling the heat sealing temperature and pressure, so that the combination of the electrode end and the battery aluminum plastic film is ensured, and the fiber lead-out path avoids the top sealing area and extends to the bottom opening along the edge of the battery cell. Side sealing area packaging: the heat sealing equipment is used to seal the two sides of the battery aluminum plastic film by controlling the heat sealing temperature and pressure. The process of the battery packaging further comprises the following steps:

5. A method of non-invasive implantation of an optical fibre sensor according to claim 4, characterised in that, One sealing area packaging: firstly, the fiber is led out from the reserved opening, and the preliminary sealing is carried out at the end far away from the tab, that is, the one sealing area, and the injection port is left; meanwhile, a circle of sealant is coated around the opening for preliminary isolation, then the electrolyte is injected through the injection port, and the preliminary sealing of the one sealing area is completed; Two sealing area and opening sealing: after the battery is subjected to the formation and exhaust processes, the final vacuum heat sealing is carried out to complete the two sealing area packaging, so that the battery monomer is completely sealed. The application relates to a negative electrode sheet and a battery with a fiber sensor.

6. A lithium-ion battery, characterized by The application relates to a negative electrode sheet and a battery with a fiber sensor. ​

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