Large size battery fiber optic sensor layout evaluation method and system

Abstract

The application belongs to the field of battery monitoring, and provides a large-size battery optical fiber sensor layout evaluation method and system. A battery surface is discretized into a battery model, the battery model includes a plurality of diagonal line length resolution squares arranged in a matrix form, and the center point of each grid and the key detection area of the battery charging and discharging process are marked. An optical fiber sensor layout scheme is mapped to the discretized battery model, the optical fiber sensor layout scheme includes the layout position, layout shape, layout mode of the optical fiber sensor and the parameters of the selected optical fiber sensor. The optical fiber measurement point coverage score, optical fiber length score, optical fiber bending score and optical fiber turning score are calculated respectively, and then fused to calculate the final total score of the optical fiber sensor layout. Whether the optical fiber sensor layout scheme is appropriate is evaluated according to the total score. The application can scientifically evaluate the optical fiber layout scheme when detecting the battery performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of battery monitoring, and particularly relates to a large-size battery optical fiber sensor layout evaluation method and system. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] In the era of rapid construction of new energy vehicles and large-scale energy storage systems, the safety performance, working efficiency and life cycle of lithium ion batteries as the core carrier of energy storage have become the core elements restricting the upgrading of the industry. In order to improve the intelligent level of the battery management system (BMS), realize early warning of thermal runaway and prolong the service life of the battery, it is crucial to monitor the key state parameters inside the battery in real time and accurately. Under the demand of this technical breakthrough, optical fiber sensors, with their micron-level size, strong anti-electromagnetic interference capability, high sensitivity characteristics and distributed measurement advantages, have shown irreplaceable technical value and application prospect in the field of lithium ion battery internal state monitoring, and have become a key technical path to break through the limitations of traditional monitoring methods and promote the safety and performance of batteries.

[0004] At present, some progress has been made in the research of applying optical fiber sensors to lithium ion batteries and detecting their key parameters. For example, a large prismatic battery is wrapped around a circle by a distributed optical fiber (based on Rayleigh scattering principle), and a temperature field measurement with a spatial resolution of about 3 mm is realized, and the hot spot distribution near the current tab is identified. Although this research can effectively identify the hot spot distribution, there are still many defects in the optical fiber layout. The current optical fiber layout scheme can be roughly divided into two types, one is to rely on experience to cover multiple key areas, and the other is to cover all areas comprehensively. However, both of these two layout schemes will lead to redundant laying of optical fiber network or monitoring blind area, which not only increases the cost but also affects the battery performance, resulting in that the optical fiber sensor cannot fully meet the scientific and accurate monitoring needs. SUMMARY

[0005] In order to solve the above problems, the present application proposes a large-size battery optical fiber sensor layout evaluation method and system, which can scientifically evaluate the optical fiber layout scheme when detecting the battery performance.

[0006] According to some embodiments, the present application adopts the following technical scheme:

[0007] The large-size battery optical fiber sensor layout evaluation method comprises the following steps:

[0008] discretize the surface of the battery into a battery model, the battery model comprising a plurality of squares arranged in a matrix with diagonal length of resolution of the fiber sensor, marking a center point of each square and a key detection area of the battery charging and discharging process;

[0009] mapping the fiber sensor layout scheme onto the discretized battery model, the fiber sensor layout scheme comprising layout positions, layout shapes, layout manners of the fiber sensor and parameters of the selected fiber sensor;

[0010] calculating a distance between the center point of each square and the nearest fiber measurement point, judging whether the corresponding square can be covered by the corresponding fiber measurement point according to the calculated distance, combining whether the fiber measurement point covers the key detection area, and calculating a fiber measurement point coverage score;

[0011] According to the fiber sensor layout scheme, the fiber length is calculated, the fiber length and the budget fiber length are compared, and the fiber length score is calculated;

[0012] According to the fiber sensor layout scheme, the fiber bending curvature of each position is calculated, the fiber bending curvature and the maximum curvature allowed by the fiber are compared, the over-standard curvature is calculated, the average curvature energy density is calculated according to the over-standard curvature, and then the fiber bending score is calculated;

[0013] According to the fiber sensor layout scheme, the number of fiber turns is calculated, the number of fiber turns and the budget number of turns are compared, and the fiber turning score is calculated;

[0014] Fusion of fiber measurement point coverage score, fiber length score, fiber bending score and fiber turning score, the total score of the final fiber sensor layout is calculated, and whether the fiber sensor layout scheme is suitable is evaluated according to the total score.

[0015] As an alternative embodiment, the process of marking the center point of each square and the key detection area of the battery charging and discharging process comprises: recording the intersection point of two diagonals of each square as the center point of the corresponding square, and defining the heat concentration area in the battery charging and discharging process as the key detection area according to the general heat generation law in the battery charging and discharging process.

[0016] As an alternative embodiment, the process of calculating the distance between the center point of each square and the nearest fiber measurement point, and judging whether the corresponding square can be covered by the corresponding fiber measurement point according to the calculated distance comprises:

[0017] measuring the shortest distance between the center point of the corresponding square and the fiber measurement point d i , the Euclidean distance in two-dimensional plane, and the geodesic distance in three-dimensional plane;

[0018] the shortest distanced i The score is calculated by substituting into the square score formula, and the specific formula is:

[0019] ;

[0020] In the formula, p is the decay coefficient, which is used to control the steepness of the score curve, p The greater the score curve is steeper, that is, the farther the distance, the faster the score decreases; is the score control coefficient, which is used to control the coverage of the score, that is, when , ;

[0021] According to the square score, it is judged whether the square is covered by the measurement point. If , it is recorded that the corresponding square is covered by the measurement point; If , the corresponding square is not covered by the measurement point, is a preset threshold.

[0022] As an optional implementation, in combination with whether the fiber measurement point covers the key detection area, the process of calculating the fiber measurement point coverage score includes:

[0023] The fiber measurement point coverage score calculation formula is:

[0024] ;

[0025] In the formula, is the maximum score when all squares are covered, which is used to normalize , is the score of each fiber measurement point, and the specific formula is as follows:

[0026] ;

[0027] In the formula, n is the number of ordinary area square covered by the fiber measurement point, m is the number of key area square covered by the fiber measurement point, is the key area square weighting coefficient. When the square score , it is judged whether the square is a square in the key detection area. If it is a key area square, it is added by one. If it is a square in the non-key detection area, it is added by one. m n

[0028] ​As an alternative embodiment, the process of calculating the fiber length, comparing the fiber length with the fiber budget length, and calculating the fiber length score includes evaluating using a fiber length score function, scoring 0 when the fiber length is not more than the budget fiber length, and scoring after the fiber length exceeds the budget fiber length, and the score calculation formula is:

[0029] ;

[0030] wherein, X L is the over budget function:

[0031] ;

[0032] L budget is the fiber budget length, and is the perimeter or single side length of the area to be measured.

[0033] As an alternative embodiment, the process of calculating the fiber length, comparing the fiber length with the fiber budget length, and calculating the fiber length score includes evaluating using a fiber length score function, scoring 0 when the fiber length is not more than the budget fiber length, and scoring after the fiber length exceeds the budget fiber length, and the score calculation formula is: k max :

[0034] ;

[0035] wherein, is the minimum bending radius allowed by the fiber;

[0036] calculating the over-standard curvature k excess， For each point on the curve, the degree to which it exceeds the maximum curvature is calculated, i.e.:

[0037] ;

[0038] wherein, k is the curvature corresponding to the current point, which is calculated as follows:

[0039] ;

[0040] is the first order derivative of the path with respect to the arc length, is the second order derivative of the path with respect to the arc length.

[0041] As an alternative embodiment, the process of calculating the average curvature energy density according to the over-standard curvature and calculating the fiber bending score includes: for each over-standard curvature, calculating the square sum and performing a normalization calculation, and the average curvature energy density E is:

[0042] ;

[0043] wherein L is the total length of the path;

[0044] Calculate the fiber bending score:

[0045] ;

[0046] wherein E 0 is the fractional mapping half penalty point, i.e. when , S bend =0.5; X E is the fiber length score, i.e. the energy exceeding the budget is scored, and the energy not exceeding the budget is not scored, and the specific formula is:

[0047] ;

[0048] E budget is the budget energy.

[0049] As an optional implementation, according to the fiber sensor layout scheme, the number of fiber turns is calculated, and then the fiber turn score is calculated, and the process includes:

[0050] ;

[0051] wherein, T 0 is the fractional mapping half penalty point, i.e. when , S turn =0.5; X T is the over budget function, which produces a score when the actual number of turns exceeds the expected number of turns:

[0052] ;

[0053] wherein, N turn_budget is the budget number of turns, N turn is the actual number of turns, and the actual number of turns is calculated by judging the slope of the curve, and the number of turns is increased by one when the sign of the slope changes.

[0054] As an optional implementation, the fiber measurement point coverage score, the fiber length score, the fiber bending score and the fiber turn score are fused to calculate the final total score of the fiber sensor layout , and the process includes:

[0055] ;

[0056] In the formula, W covered , W length , W bend , W turn The proportion coefficient of the optical fiber measurement point coverage score , the optical fiber length score , the optical fiber bending score and the optical fiber turning score reflects its importance in evaluation, which is determined according to the evaluation requirements.

[0057] The large-size battery optical fiber sensor layout evaluation system comprises:

[0058] The discrete model construction module is configured to discretize the battery surface area into a battery model, the battery model comprising a plurality of squares with diagonal line length of resolution arranged in a matrix, and marking the center point of each square and the key detection area of the battery charging and discharging process;

[0059] The mapping module is configured to map the optical fiber sensor layout scheme to the discretized battery model, the optical fiber sensor layout scheme comprising the layout position, layout shape, layout mode and parameters of the selected optical fiber sensor;

[0060] The optical fiber measurement point coverage evaluation module is configured to calculate the distance between the center point of each square and the nearest optical fiber measurement point, determine whether the corresponding square can be covered by the corresponding optical fiber measurement point according to the calculated distance, and calculate the optical fiber measurement point coverage score by combining whether the optical fiber measurement point covers the key detection area;

[0061] The optical fiber length evaluation module is configured to calculate the optical fiber length according to the optical fiber sensor layout scheme, compare the optical fiber length with the optical fiber budget length, and calculate the optical fiber length score;

[0062] The optical fiber bending evaluation module is configured to calculate the optical fiber bending curvature at each position according to the optical fiber sensor layout scheme, compare the optical fiber bending curvature with the maximum curvature allowed by the optical fiber, calculate the over-standard curvature, calculate the average curvature energy density according to the over-standard curvature, and further calculate the optical fiber bending score;

[0063] The optical fiber turning evaluation module is configured to calculate the number of optical fiber turning according to the optical fiber sensor layout scheme, and further calculate the optical fiber turning score;

[0064] The fusion evaluation module is configured to fuse the optical fiber measurement point coverage score, the optical fiber length score, the optical fiber bending score and the optical fiber turning score, calculate a final total score of the optical fiber sensor layout, and evaluate whether the optical fiber sensor layout scheme is suitable according to the total score.

[0065] Compared with the prior art, the present application has the following beneficial effects:

[0066] The present application comprehensively evaluates the designed optical fiber layout scheme from four aspects of optical fiber measurement point coverage, optical fiber length exceeding the budget, optical fiber bending and optical fiber turning, can objectively evaluate whether the optical fiber layout scheme is reasonable, and selects an optical fiber layout scheme that can meet the scientific and accurate monitoring requirements under different conditions, and solves the problem that there is no scientific evaluation method for the optical fiber layout scheme when the battery performance is detected by the optical fiber sensor.

[0067] In order to make the above-mentioned objects, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are used for explanation. BRIEF DESCRIPTION OF DRAWINGS

[0068] The drawings accompanying the specification of the present application form a part of the present application, the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0069] Figure 1 It is a soft package battery discrete visualization model and key area calibration condition in an embodiment;

[0070] Figure 2 It is a cylindrical battery discrete visualization model and key area calibration condition in an embodiment;

[0071] Figure 3 It is an optical fiber layout scheme evaluation flowchart in an embodiment;

[0072] Figure 4 It is a soft package battery optical fiber path measurement point schematic diagram in an embodiment;

[0073] Figure 5 It is a soft package battery optical fiber path measurement point score schematic diagram in an embodiment;

[0074] Figure 6 It is a soft package battery optical fiber path measurement point score schematic diagram in an embodiment;

[0075] Figure 7 It is a soft package battery optical fiber path measurement point score schematic diagram in an embodiment;

[0076] Figure 8 is a fiber path for a pouch cell in an embodiment is a plot of measurement point scores

[0077] Figure 9 is a plot of measurement points for a fiber path for a cylindrical cell in an embodiment

[0078] Figure 10 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment

[0079] Figure 11 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment

[0080] Figure 12 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment

[0081] Figure 13 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment

[0082] Figure 14 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment

[0083] Figure 15 is a plot of measurement point scores for a helical fiber path for a cylindrical cell in an embodiment DETAILED DESCRIPTION

[0084] The present application will be further described with reference to the drawings and embodiments.

[0085] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the 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.

[0086] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. 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.

[0087] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0088] Embodiment One

[0089] Evaluation methods for the deployment of large-size battery fiber optic sensors, such as Figure 3 As shown, it includes the following steps:

[0090] (a) Discretization of battery surface area and calibration of key areas

[0091] Discretize the battery surface into N A square with a diagonal length of resolution is given, and the intersection of the two diagonals of the square is denoted as . O i，j (No. i Line number j (The center point of the square is listed). Based on the general heat generation patterns during battery charging and discharging, key detection areas for the battery charging and discharging process are defined (marked with solid red lines), such as... Figure 1 , Figure 2 As shown.

[0092] The fiber optic sensor deployment scheme is mapped onto the discrete battery model. The fiber optic sensor deployment scheme includes the deployment location, shape, method, and parameters of the selected fiber optic sensors.

[0093] (ii) Coverage score of fiber optic measurement points

[0094] The main purpose of this scoring section is to assess the coverage of fiber optic measurement points, observe the utilization of each point, and prevent duplicate measurements in certain areas or underutilization of fiber optic measurement points. The specific scoring formula is as follows:

[0095] (1)

[0096] In the formula, It is the maximum score when all squares are covered, used for normalization. , This is the score for each fiber optic measurement point, and its specific formula is as follows:

[0097] (2)

[0098] In the formula, n This represents the number of squares in the ordinary area covered by the fiber optic measurement points. m This represents the number of square areas covered by the fiber optic measurement points. These are the weighting coefficients for the key area square.

[0099] To make a scientific and objective judgment m and n Regarding the specific numerical values, this invention proposes the following evaluation method: using the center point of each square... O i,jFor the origin, calculate the distance between the point and the nearest fiber measurement point, and determine whether the square can be better covered by the measurement point according to the distance. The specific determination steps are:

[0100] (1) Measure the shortest distance between the square center point and the fiber measurement point d i (Euclidean distance in two-dimensional plane, geodesic distance in three-dimensional plane).

[0101] (2) Substitute the shortest distance d i into the square score formula to calculate the score, and the specific formula is:

[0102] (3)

[0103] In the formula, p is the attenuation coefficient, which controls the steepness of the score curve, p The larger the score curve is steeper, that is, the farther the distance, the faster the score decreases; is the score control coefficient, which is used to control the coverage range of the score, that is, when , .

[0104] (3) Determine whether the square is covered by the measurement point according to the square score, and the judgment standard is as follows: When , it is recorded that the square is covered by the measurement point;

[0105] (4) Determine the specific value of m and n: when , determine whether the square is a key area square, if it is a key area square, then m add one, if it is a non-key area square, then n add one.

[0106] (Three) Fiber length score

[0107] This part of the score function is an over-budget score function, that is, when the fiber length does not exceed the budget, the score is 0, and after exceeding the budget, the fiber length is scored, the more it exceeds, the higher the score, the value range of the function is [0, 1], the main purpose is to limit the meaningless extension of the fiber and reduce the waste of the fiber. The specific score formula is as follows:

[0108] (4)

[0109] In the formula X L is the over-budget function:

[0110] (5)

[0111] L budget The fiber budget length is the length when simply covering the measurement area, such as the perimeter or the single side length of the measurement area.

[0112] (Four) Fiber bending score

[0113] Excessive bending of the optical fiber will cause a sharp increase in signal transmission loss. When the bending radius is less than the minimum bending radius allowed by the optical fiber, the optical signal will produce serious scattering and leakage at the core-cladding interface, causing the monitoring signal to attenuate and affecting the measurement accuracy of temperature, strain and other parameters. Therefore, the bending radius of the optical fiber should be limited when laying the optical fiber, and the curvature is a direct factor reflecting the bending radius, so the curvature can be used to evaluate the bending degree of the optical fiber. The specific evaluation steps are as follows:

[0114] (1) Calculate the maximum curvature allowed by the optical fiber k max .

[0115] (6)

[0116] In the formula, is the minimum bending radius allowed by the optical fiber.

[0117] (2) Calculate the over-standard curvature k excess .

[0118] For each point on the curve, calculate the degree of exceeding , and the specific calculation formula is as follows:

[0119] (7)

[0120] In the formula, k is the curvature corresponding to the current point, and its calculation method is as follows:

[0121] (8)

[0122] is the first-order derivative of the path with respect to the arc length, is the second-order derivative of the path with respect to the arc length. This calculation method is suitable for two-dimensional and three-dimensional curvature calculation, and ensures the robustness of the calculation.

[0123] (3) Calculate the average curvature energy density E.

[0124] For each over-standard curvature, calculate the sum of its squares and perform a normalization calculation, so that the bending degree of paths with different lengths is comparable. The specific calculation formula is as follows:

[0125] (9)

[0126] where L is the total length of the path.

[0127] (4) Calculate the fiber bending score.

[0128] (10)

[0129] where E 0 is the fractional mapping half penalty point, i.e. when , S bend = 0.5; X E is the fiber length score, i.e. the energy exceeding the budget will be scored, and no score will be given if the budget is not exceeded, and the specific formula is:

[0130] (11)

[0131] E budget is the budget energy.

[0132] (Five) Fiber turning score

[0133] The main purpose of this part of the score is to suppress unnecessary high-frequency turning and oscillation in the path. The specific formula is as follows:

[0134] (12)

[0135] where, T0 is the fractional mapping half penalty point, i.e. when , S turn = 0.5; X T is the over budget function, which is an over budget function, and a score is generated when the actual turning number exceeds the expected turning number.

[0136] (13)

[0137] where, N turn_budget is the budget turning number, N turn is the actual turning number, which is calculated by judging the slope of the curve, and the turning number is increased by one when the sign of the slope changes.

[0138] (Six) Fiber laying system fusion score

[0139] To make the above score more intuitive and systematic, a fiber layout system score is defined, which reflects the measurement point coverage, fiber length, fiber bending degree and fiber turning of the fiber layout scheme, and the specific formula is:

[0140] (14)

[0141] In the formula, W covered , W length , W bend , W turn are the fiber length score, the fiber bending degree score, the fiber turning score, and the proportion coefficient reflecting their importance in the scoring system, respectively.

[0142] To verify the effectiveness of the large-size battery fiber sensor layout evaluation method and system proposed in the present application, the following describes in detail the comprehensive evaluation of the system in different fiber layout schemes, taking cylindrical batteries and soft-pack batteries as research objects, respectively.

[0143] Example 1: Comprehensive evaluation of soft-pack battery fiber layout scheme

[0144] The object to be observed in this example is a rectangular area, the size of which is composed of 48 squares along the length direction and 16 squares along the width direction. The diagonal length of each square corresponds to the resolution of the fiber. The cosine type fiber layout scheme is now systematically evaluated. The following specific steps are involved:

[0145] (1) Define the specific parameters of the fiber layout scheme.

[0146] In this example, a fiber with a resolution of 1.28 mm is used for measurement, i.e. a fiber measurement point is generated every 1.28 mm. The preset fiber path is a cosine path, and the specific analytical expression is:

[0147] (15)

[0148] In the formula L plot represents the length of the rectangle, W plot represents the width of the rectangle, N wave represents the period number of the cosine function in [0, L plot ] in this example L plot , W plot , N wave43.44, 14.48, 3, the expression after simplification is .

[0149] Then the light path is discretized into fiber measurement points at intervals of 1.28 mm, and the fiber measurement points are represented by black dots, as shown in Figure 4 .

[0150] (2) Fiber measurement point coverage score calculation

[0151] First, calculate the Euclidean shortest distance between the square center point and the fiber measurement point , d ,

[0152] (16)

[0153] Then substitute it into the square score formula to calculate its score and determine whether the square is covered by the measurement point:

[0154] (17)

[0155] The parameters used in this embodiment are as follows: The side length of the square is 0.9; the attenuation index p is 2; S min is 0.5.

[0156] Then determine whether the square is covered, that is, the value is greater than or equal to 0.5, which indicates that the square is covered. Then determine whether the square is in the key area, if yes, m add one, if not, n add one.

[0157] Then calculate the detection score of the fiber measurement point, that is:

[0158] (18)

[0159] In this embodiment, the parameter is equal to 1, that is, the measurement point detects a normal square and adds one point, and detects a key area square and adds two points. The detection score of each measurement point is shown in Table 1 (X i,j in the table represents the ijth measurement point, for example, X 2,3 represents the 23rd measurement point):

[0160] Table 1 Fiber routing path Fiber measurement point detection score

[0161]

[0162] For the convenience of observation, the scores of the measurement points in the path are visualized, and the scores of the measurement points are displayed through their colors. The darker the color, the higher the score, and the score of each measurement point is more intuitively displayed. As shown in Figure 5 .

[0163] Finally, the total score of all measurement points is calculated and normalized:

[0164] (19)

[0165] In this embodiment, the total number of squares is 768, and the number of squares in the key area is 168. When all the squares are covered, the total score , and the calculation result is .

[0166] (3) Fiber length score calculation

[0167] Because the score in this part is the fiber length score, which is scored only when the length exceeds the budget. Therefore, first calculate the fiber budget length and the fiber actual length of the layout scheme. In this embodiment, the budget length is , that is, 86.84 mm, and the actual fiber length is calculated to be 100.13 mm.

[0168] Secondly, calculate the over budget function value, that is:

[0169] (20)

[0170] The calculation result is .

[0171] Finally, calculate the fiber length score, that is:

[0172] (21)

[0173] In the above X L代入 The calculation result is .

[0174] (4) Fiber bending score calculation

[0175] In this embodiment, the minimum bending radius of the fiber is 10 mm, that is .

[0176] First, calculate the function over-standard curvature and integrate and sum the over-standard curvature and then normalize, that is:

[0177] (22)

[0178] (23)

[0179] = 0.263, k = 0.082. E = 0.082.

[0180] The over budget energy is then calculated, i.e.

[0181] (24)

[0182] The fiber bending score is then calculated, i.e. E budget = 0.0012. X E = 0.0012.

[0183] The fiber bending score is then calculated, i.e.

[0184] (25)

[0185] = 0.0012. E = 0.0012. S bend = 0.0012.

[0186] (5) Fiber turning score

[0187] The fiber turning number is first calculated, i.e. the number of times the sign of the slope changes, and the cosine path turning number is selected as 5 in this embodiment, i.e. N turn = 5.

[0188] The over budget function value is then calculated, i.e. X turn = 0.0012.

[0189] (26)

[0190] The budget turning number N turn_budget = 8, so X T = 0.

[0191] The fiber turning score is then calculated, i.e.

[0192] (27)

[0193] Since X T = 0, so S turn = 0.

[0194] (6) Fiber layout scheme fusion score

[0195] Substituting the scores from each of the above calculations into the scoring formula yields the system's total score, i.e.:

[0196] (28)

[0197] The parameter values ​​are as follows: W covered =1, W length =0.2, W bend =0.2, W turn =0.2. The final calculated total system score is: S total =0.2606.

[0198] To further verify the effectiveness of the large-size battery fiber optic sensor deployment evaluation method and system proposed in this invention, this embodiment uses four different cosine paths as the evaluation schemes, with the degree of curvature and the number of turns increasing sequentially for the four cosine paths. Figure 6 This is a schematic diagram of the fiber optic measurement point scores for fiber optic deployment scheme 1, showing its path function. ; Figure 5 This is a schematic diagram of the fiber optic measurement point scores for fiber optic deployment scheme 2, and its path function is: ; Figure 7 This is a schematic diagram of the fiber optic measurement point scores for fiber optic deployment scheme 3, and its path function is: ; Figure 8 This is a schematic diagram of the fiber optic measurement point scores for fiber optic deployment scheme 4, and its path function is: .

[0199] As the fiber optic paths become denser, the changes in their core scores are shown in Table 2:

[0200] Table 2 Comparison of Core Scores for Different Fiber Optic Deployment Paths

[0201]

[0202] As shown in the table above, as the period of the cosine function decreases, the length of the fiber optic path gradually increases, leading to increased coverage. However, the fiber length score also increases, along with the degree of bending and the number of turns. This results in a gradual increase in coverage but not in the overall score. The data in the table also shows that while Scheme 4 has a higher coverage than Scheme 2, its bending score is too high, exceeding the normal bending tolerance of the fiber. Therefore, Scheme 2 is superior to the other schemes, demonstrating the effectiveness of this evaluation method.

[0203] Example 2: Comprehensive Evaluation of Fiber Optic Deployment Scheme for Cylindrical Cells

[0204] This embodiment takes a cylinder with a base radius of 6.9 mm and a height of 14.5 mm as the observation object to evaluate the spiral fiber layout scheme. The specific steps are as follows:

[0205] (1) Clearly define the specific parameters of the fiber layout scheme.

[0206] This embodiment uses a fiber with a resolution of 1.28 mm for measurement. First, the area to be observed is discretized into 768 squares with a diagonal of the fiber resolution and the key areas are labeled, as shown in Figure 2 . The preset fiber path is a spiral path, and the specific expression is:

[0207] (29)

[0208] In the formula, L plot represents the circumference of the cylinder base, W plot represents the height of the cylinder, , , N represents the number of turns of the spiral on the cylinder as 3, and the parameters are substituted into the expression as .

[0209] Then, the light path is discretized into fiber measurement points at intervals of 1.28 mm, as shown in Figure 9 .

[0210] (2) Fiber measurement point coverage score calculation

[0211] First, calculate the shortest distance (geodesic distance) on the cylindrical surface between the center point of the square and the fiber measurement point d , , is the angle difference between the center point and the measurement point, is the height difference between the center point and the measurement point. The remaining steps are the same as in Example One, and the same parameters are used for convenience. The detection score of each measurement point is shown in Table 3 (X i,j represents the ijth measurement point, such as X 2,3 represents the 23rd measurement point):

[0212] Table 3 Fiber layout spiral path measurement point detection score

[0213]

[0214] For convenience of observation, the fiber measurement point scores in the path are visualized and the cylinder is unfolded along the generatrix to form a rectangle, which more intuitively shows the score of each fiber measurement point, as shown in Figure 10 , 11 .

[0215] Finally, the total score of all measurement points is calculated and normalized. In this embodiment, the total number of square cylinders is 768, and the number of squares in the focus area is 48. When all squares are covered, , the calculation is .

[0216] (3) Fiber length score calculation

[0217] The same as in Example 1, the fiber budget length and the actual length in this embodiment need to be calculated first. Since the detection area in this embodiment is a cylinder with a bottom radius of 6.9 mm and a height of 14.5 mm, the budget length is 3.5 times the circumference of the bottom, i.e. 152.06 mm; the actual length of the fiber is 131.14 mm. That is, the over budget function value is X L =0, S length =0.

[0218] (4) Fiber bending score calculation

[0219] The same as the fiber used in Example 1, the minimum bending radius is 10 mm, i.e. .

[0220] First, calculate the function over-standard curvature and integrate and sum the over-standard curvature, then normalize, i.e. k =0.3341, E =0.079. Then calculate the over-standard energy, in this embodiment, choose E budget 0.01, the calculation can get X E =0.069.

[0221] Finally, calculate the fiber bending score, S bend =0.9856.

[0222] (5) Fiber turning score

[0223] Since the spiral path selected in this embodiment is a one-way upward path, the number of turns is 0, i.e. S turn =0.

[0224] (6) Fiber laying scheme system fusion score

[0225] The calculation results of each part of the score are substituted into the scoring formula to get the system comprehensive score, i.e.

[0226] (30)

[0227] The parameter values are as follows:W covered = 1, W length = 0.5, W bend = 0.3, W turn = 0.2. Finally, the total score of the system is calculated as: S total = 0.0272.

[0228] To further verify the effectiveness of the large-size battery fiber sensor layout evaluation method and system proposed in the present application, four different spiral paths are used as the to-be-evaluated schemes in the present embodiment, and the pitches of the four spiral paths decrease in turn, that is, the number of turns of the spiral path winding on the surface of the cylinder increases in turn. Figure 12 Fig. 4 is a schematic diagram of the fiber path measurement point score of the fiber layout scheme 5, and the pitch is 1.61; Figure 13 Fig. 5 is a schematic diagram of the fiber path measurement point score of the fiber layout scheme 6, and the pitch is 1.45; Figure 14 Fig. 6 is a schematic diagram of the fiber path measurement point score of the fiber layout scheme 7, and the pitch is 1.32; Figure 15 Fig. 7 is a schematic diagram of the fiber path measurement point score of the fiber layout scheme 8, and the pitch is 1.21.

[0229] With the continuous densification of the fiber path, the changes of the core scores are as shown in Table 4:

[0230] Table 4 Comparison of core scores of different fiber layout paths

[0231]

[0232] As can be seen from the above table, since the different paths rotate around the same cylinder, the bending degree of the different paths is the same; with the continuous decrease of the pitch, the fiber coverage rate increases, but the length of the fiber path gradually increases, which causes the fiber length score to increase, resulting in that although the coverage rate gradually increases, the comprehensive score does not gradually increase. As can be seen from the data in the table, although the coverage rate of scheme 4 is higher than that of scheme 2, the fiber length score is too high, the fiber is too long, which causes fiber waste, and scheme 2 is better than other schemes, which proves the effectiveness of the evaluation method.

[0233] Embodiment Two

[0234] The large-size battery fiber sensor layout evaluation system comprises:

[0235] The discrete model construction module is configured to discretize the surface of the battery into a battery model, the battery model comprising a plurality of squares with a diagonal line length of a resolution arranged in a matrix manner, and marking a center point of each square and a key detection area of the battery charging and discharging process;

[0236] a mapping module configured to map the fiber sensor layout scheme onto the discretized battery model, the fiber sensor layout scheme including layout positions, layout shapes, layout manners of the fiber sensors, and parameters of the selected fiber sensors;

[0237] a fiber measurement point coverage evaluation module configured to calculate distances between center points of each square and the nearest fiber measurement point, determine whether the corresponding square can be covered by the corresponding fiber measurement point according to the calculated distances, and calculate a fiber measurement point coverage score by combining whether the fiber measurement point covers the key detection area;

[0238] a fiber length evaluation module configured to calculate fiber lengths according to the fiber sensor layout scheme, compare the fiber lengths with a predetermined fiber budget length, and calculate a fiber length score;

[0239] a fiber bending evaluation module configured to calculate fiber bending curvatures at various positions according to the fiber sensor layout scheme, compare the fiber bending curvatures with a maximum curvature allowed by the fiber, calculate an over-standard curvature, calculate an average curvature energy density according to the over-standard curvature, and further calculate a fiber bending score;

[0240] a fiber turning evaluation module configured to calculate a number of fiber turns according to the fiber sensor layout scheme, and further calculate a fiber turning score;

[0241] a fusion evaluation module configured to fuse the fiber measurement point coverage score, the fiber length score, the fiber bending score, and the fiber turning score, calculate a final total score of the fiber sensor layout, and evaluate whether the fiber sensor layout scheme is suitable according to the total score.

[0242] Those skilled in the art should understand that embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk memory, optical storage, etc.) having computer-usable program code contained therein or thereon. CD - ROM

[0243] ​The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0244] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0245] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0246] The application described above is merely preferred embodiments of the application, and is not intended to limit the application. Any modification, equivalent replacement and improvement made without departing from the spirit and principle of the application shall fall within the protection scope of the application.

Claims

1. A method for evaluating the deployment of large-size battery fiber optic sensors, characterized by: Includes the following steps: The battery surface is discretized into a battery model, which includes multiple squares arranged in a matrix with a resolution of diagonal length. The center point of each square and the key detection area during the battery charging and discharging process are marked. Specifically, the intersection of the two diagonals of each square is recorded as the center point of the corresponding square, and the area where the heat is concentrated during the battery charging and discharging process is defined as the key detection area based on the general heat generation pattern during the battery charging and discharging process. The fiber optic sensor deployment scheme is mapped onto the discrete battery model. The fiber optic sensor deployment scheme includes the deployment location, shape, method, and parameters of the selected fiber optic sensors. Calculate the distance between the center point of each square and the nearest fiber optic measurement point. Based on the calculated distance, determine whether the corresponding square can be covered by the corresponding fiber optic measurement point. Combine this with whether the fiber optic measurement point covers the key detection area to calculate the fiber optic measurement point coverage score. Based on the fiber optic sensor deployment plan, the fiber length is calculated, the fiber length is compared with the fiber budget length, and the fiber length score is calculated. Based on the fiber optic sensor deployment scheme, the fiber bending curvature at each location is calculated. The fiber bending curvature is compared with the maximum allowable curvature of the fiber to calculate the excess curvature. The average curvature energy density is calculated based on the excess curvature, and then the fiber bending score is calculated. Based on the fiber optic sensor deployment scheme, the number of fiber optic turning times is calculated, and then the fiber optic turning score is calculated. By integrating the fiber optic measurement point coverage score, fiber length score, fiber bending score, and fiber reversal score, the final total score for the fiber optic sensor deployment is calculated. The suitability of the fiber optic sensor deployment scheme is evaluated based on the total score, specifically including: In the formula, W covered , W length , W bend , W turn The coverage score of the fiber optic measurement points is as follows. Fiber optic length rating Fiber optic bending score and fiber optic steering score The percentage coefficient reflects its importance in the assessment and is determined according to the assessment requirements.

2. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 1, characterized in that, The process of calculating the distance between the center point of each square and the nearest fiber optic measurement point, and determining whether the corresponding square can be covered by the corresponding fiber optic measurement point based on the calculated distance, includes: Measure the shortest distance between the center point of the corresponding square and the fiber optic measurement point. d i In a two-dimensional plane, it is the Euclidean distance; in a three-dimensional plane, it is the geodesic distance. Shortest distance d i Substitute the values ​​into the square scoring formula to calculate the score. The specific formula is as follows: In the formula, p This is the attenuation coefficient, used to control the steepness of the score curve. p The larger the value, the steeper the score curve, meaning the farther the distance, the faster the score decreases. This is a scoring control coefficient used to control the coverage of scores, i.e., when... hour, ; Determine whether the square is covered by the measurement point based on the square score. When the measurement point is covered, it is recorded as the corresponding square. The corresponding square is not covered by the measurement point. This is the preset threshold.

3. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 1, characterized in that, The process of calculating the fiber optic measurement point coverage score, based on whether the fiber optic measurement points cover the key detection area, includes: The formula for calculating the coverage score of fiber optic measurement points is as follows: In the formula, It is the maximum score when all squares are covered, used for normalization. , This is the score for each fiber optic measurement point, and its specific formula is as follows: In the formula, n This represents the number of ordinary squares covered by the fiber optic measurement points. m The number of key squares covered by the fiber optic measurement points. It is the weighting coefficient of the key area square, when the square score When the square is within the key detection area, determine whether it is a square within the key detection area. If it is a square within the key detection area, then... m Add one, if it is a square within a non-key detection area, then n Add one.

4. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 1, characterized in that, The fiber length is calculated and compared to the predetermined fiber budget length. The fiber length score calculation process includes evaluation using a fiber length scoring function. A score of 0 is given if the fiber length does not exceed the budget; a score is given for fiber lengths exceeding the budget. The scoring formula is as follows: In the formula, X L For over-budget functions: L budget The fiber optic budget length is denoted as , and the perimeter or side length of the area to be measured is denoted as .

5. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 1, characterized in that, The process of calculating the fiber optic bending curvature at various locations and comparing it with the maximum allowable curvature of the fiber includes: calculating the maximum allowable curvature of the fiber. k max : In the formula, It is the minimum bending radius allowed for optical fiber; Calculate the excessive curvature k excess， For each point on the curve, calculate its excess curvature. The degree, that is: In the formula, k It is the curvature corresponding to the current point, and it is calculated as follows: It is the first derivative of the path with respect to the arc length. It is the second derivative of the path with respect to the arc length.

6. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 5, characterized in that, The process of calculating the average curvature energy density based on the excessive curvature, and then calculating the fiber bending score, includes: for each excessive curvature, calculating its sum of squares and normalizing it; the average curvature energy density E is: In the formula L This represents the total path length. Calculate fiber optic bending score: In the formula E 0 is the half-penalty point of the fractional mapping, that is, when hour, S bend =0.5; X E This is fiber length scoring, meaning that energy exceeding the budget is scored, while energy within the budget is not scored. The specific formula is as follows: E budget For budgeted energy.

7. The method for evaluating the deployment of large-size battery fiber optic sensors as described in claim 1, characterized in that, Based on the fiber optic sensor deployment scheme, the number of fiber optic turning cycles is calculated, and then the fiber optic turning score is calculated. The process includes: In the formula, T 0 is the half-penalty point of the fractional mapping, that is, when hour, S turn =0.5; X T This is an over-budget function that generates a score when the actual number of turns exceeds the expected number of turns. In the formula, N turn_budget For the number of budget shifts, N turn This represents the actual number of turns. The actual number of turns is calculated by judging the slope of the curve. When the sign of the slope changes, the number of turns is incremented by one.

8. A large-size battery fiber optic sensor deployment evaluation system, employing the large-size battery fiber optic sensor deployment evaluation method as described in any one of claims 1-7, characterized in that, include: The discrete model building module is configured to discretize the battery surface into a battery model, which includes multiple squares with a resolution of diagonal length arranged in a matrix, and marks the center point of each square and the key detection area of ​​the battery charging and discharging process. The mapping module is configured to map the fiber optic sensor deployment scheme onto the discrete battery model. The fiber optic sensor deployment scheme includes the deployment location, shape, method, and parameters of the selected fiber optic sensors. The fiber optic measurement point coverage assessment module is configured to calculate the distance between the center point of each square and the nearest fiber optic measurement point. Based on the calculated distance, it determines whether the corresponding square can be covered by the corresponding fiber optic measurement point. Combining this with whether the fiber optic measurement point covers the key detection area, a fiber optic measurement point coverage score is calculated. The fiber optic length assessment module is configured to calculate the fiber optic length based on the fiber optic sensor deployment plan, compare the fiber optic length with the predetermined fiber optic budget length, and calculate the fiber optic length score. The fiber optic bending assessment module is configured to calculate the fiber bending curvature at each location based on the fiber optic sensor deployment scheme, compare the fiber bending curvature with the maximum allowable curvature of the fiber, calculate the excess curvature, calculate the average curvature energy density based on the excess curvature, and then calculate the fiber bending score. The fiber optic steering evaluation module is configured to calculate the number of fiber optic steerings based on the fiber optic sensor deployment scheme, and then calculate the fiber optic steering score. The fusion evaluation module is configured to fuse fiber optic measurement point coverage scores, fiber optic length scores, fiber optic bending scores, and fiber optic reversal scores to calculate the final total score of the fiber optic sensor deployment. The appropriateness of the fiber optic sensor deployment scheme is evaluated based on the total score.

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