Battery monitoring method and device, battery module and storage medium

Abstract

The embodiment of the invention provides a battery monitoring method and device, a battery module and a storage medium, and relates to the technical field of batteries. The method comprises the following steps: for each first fiber bragg grating, respectively measuring a first reflection wavelength variation corresponding to a first sub-measuring point and a second reflection wavelength variation corresponding to a second sub-measuring point; based on a difference value between the first reflection wavelength variation and the second reflection wavelength variation corresponding to each first fiber grating, determining a fiber dependent variable corresponding to each first fiber grating; and determining the health state of the battery module based on the optical fiber dependent variable. According to the embodiment of the invention, the accuracy of the optical fiber dependent variable is effectively improved, and the accuracy of the battery SOH is further improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery monitoring method, device, battery module and storage medium. Background Art

[0002] With the widespread adoption of lithium-ion batteries in electric vehicles and energy storage systems, the state of health (SOH) of batteries has become a key indicator for assessing the degree of performance degradation of lithium-ion batteries. Accurate SOH assessment has become a core industry requirement. Traditional SOH monitoring methods rely primarily on voltage / current curve analysis or temperature monitoring, which suffers from low assessment accuracy. Summary of the Invention

[0003] The present application provides a battery monitoring method, device, battery module and storage medium, which are used to solve the problem of low SOH assessment accuracy in the prior art.

[0004] According to one aspect of the present application, a battery monitoring method is provided, which is applied to a battery module. The battery module includes a battery cell connection system and multiple battery cells. The battery cell connection system includes multiple copper bars, each copper bar spanning a preset number of battery cells. At least one first fiber Bragg grating is provided on a surface of each copper bar. Each first fiber Bragg grating includes a first sub-measuring point and a second sub-measuring point. The distance between the first sub-measuring point and the second sub-measuring point is less than a preset distance threshold. The method includes:

[0005] For each first fiber Bragg grating, a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point are measured respectively; wherein the first reflection wavelength change and the second reflection wavelength change are both changes relative to an initial reflection wavelength of the first fiber Bragg grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point;

[0006] Determine the fiber strain corresponding to each first fiber Bragg grating based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating; wherein the fiber strain is used to characterize the expansion amplitude of the core;

[0007] Determine the health status of the battery module based on the optical fiber strain.

[0008] In a possible implementation, if two or more first fiber Bragg gratings are correspondingly provided on each copper busbar, the distance between two adjacent first fiber Bragg gratings on the same copper busbar is a preset distance value.

[0009] In one possible implementation, determining the health status of the battery module based on the optical fiber strain includes:

[0010] Taking the average value of the optical fiber strain corresponding to each first optical fiber Bragg grating as the average strain;

[0011] The health status of the battery module is determined based on the mean strain variable.

[0012] In another possible implementation, for each first fiber Bragg grating, measuring the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point respectively includes:

[0013] If the optical fiber measurement signal is determined, for each first optical fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively.

[0014] In another possible implementation, the above-mentioned determination of the optical fiber measurement signal is triggered based on any one of the following conditions:

[0015] Obtain the measurement time interval of the battery module, if the measurement time interval is not less than the preset time interval;

[0016] The battery cell temperature of the battery module is obtained. If the battery cell temperature is greater than a preset temperature threshold, the optical fiber measurement signal is determined.

[0017] In another possible implementation, the battery module further includes a plurality of second fiber Bragg gratings, each of which is disposed on a first surface of a target battery cell, on which a positive electrode column of the battery cell is disposed; the target battery cells are evenly spaced based on a preset number of battery cells;

[0018] Get the cell temperature of the battery module, including:

[0019] respectively measuring a change in the third reflection wavelength of each second fiber grating;

[0020] Determining a temperature change of the corresponding second fiber grating based on a third reflection wavelength change;

[0021] The cell temperature of the battery module is determined based on the temperature change.

[0022] In another possible implementation, determining the cell temperature of the battery module based on the temperature change includes:

[0023] For each second fiber Bragg grating, obtaining a corresponding initial reflected wave wavelength, and determining an initial temperature corresponding to the initial reflected wave wavelength;

[0024] Determining a temperature measurement value of each second fiber Bragg grating based on an initial temperature and a temperature variation corresponding to each second fiber Bragg grating;

[0025] The temperature of the battery cell of the battery module is determined based on the temperature measurement value of each second fiber Bragg grating.

[0026] In another possible implementation, the determining of the battery cell temperature of the battery module based on the temperature measurement value of each second fiber Bragg grating includes:

[0027] If all temperature measurement values ​​are less than the preset temperature monitoring threshold, the average of all temperature measurement values ​​is used as the battery cell temperature;

[0028] If any temperature measurement value is not less than the temperature monitoring threshold, the maximum value among the temperature measurement values ​​is taken as the battery cell temperature.

[0029] In another possible implementation, after determining the temperature measurement value of each second fiber Bragg grating, the method further includes:

[0030] Determining temperature distribution information of the battery module based on the temperature measurement value of each second fiber Bragg grating;

[0031] Determine the thermal management strategy of the battery module based on the temperature distribution information.

[0032] According to another aspect of an embodiment of the present application, a battery monitoring device is provided, which is applied to a battery module. The battery module includes a cell connection system and multiple cells. The cell connection system includes multiple copper bars, each copper bar spanning a preset number of cells. At least one first fiber Bragg grating is provided on a surface of each copper bar. Each first fiber Bragg grating includes a first sub-measuring point and a second sub-measuring point, wherein the distance between the first sub-measuring point and the second sub-measuring point is less than a preset threshold. The device includes:

[0033] a measurement module configured to measure, for each first fiber Bragg grating, a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point; wherein the first reflection wavelength change and the second reflection wavelength change are both changes relative to an initial reflection wavelength of the fiber Bragg grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point;

[0034] a strain calculation module, configured to determine the fiber strain corresponding to each first fiber Bragg grating based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating; wherein the fiber strain is used to characterize the expansion amplitude of the battery core;

[0035] The health monitoring module is used to determine the health status of the battery module based on the optical fiber strain.

[0036] According to another aspect of the present application, a battery module is provided, which includes: a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to implement the steps of the method shown in the first aspect of the present application.

[0037] According to another aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method shown in the first aspect of the present application are implemented.

[0038] The beneficial effects of the technical solution provided by this application are:

[0039] The battery monitoring method provided in this application can be performed by disposing at least one first fiber Bragg grating (FBG) on the surface of each copper busbar. For each first fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively. Then, based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating, the fiber strain corresponding to each first fiber Bragg grating is determined, so as to determine the health status of the battery module based on the fiber strain. Among them, the first reflection wavelength change at the first measurement point can represent the fiber strain, but it is also affected by temperature. Therefore, the second reflection wavelength change can be used to directly represent the fiber temperature change, so that the first reflection wavelength change can be temperature compensated according to the second reflection wavelength change, effectively improving the accuracy of the fiber strain and further improving the accuracy of the battery state of health. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] Figure 1 A schematic structural diagram of a battery module provided in an embodiment of the present application;

[0042] Figure 2 A schematic structural diagram of a first fiber Bragg grating in a battery module provided in an embodiment of the present application;

[0043] Figure 3 A flowchart of a battery monitoring method provided in an embodiment of the present application;

[0044] Figure 4 A flowchart of an exemplary battery monitoring method provided in an embodiment of the present application;

[0045] Figure 5 A schematic diagram of the structure of a battery monitoring device provided in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0048] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments of the present disclosure. These figures are not drawn to scale, and for the purpose of clarity, certain details are exaggerated and certain details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0049] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, it can be directly on the other layer / element or an intervening layer / element may be present therebetween. In addition, if a layer / element is "on" another layer / element in one orientation, it may be "below" the other layer / element when the orientation is reversed.

[0050] As the global energy transition accelerates, the large-scale application of lithium batteries in electric vehicles and energy storage systems places higher demands on battery management. SOH monitoring has become a core technology for ensuring battery safety and optimizing usage strategies. Accurate SOH assessment is crucial for predicting remaining battery life, formulating maintenance strategies, and ensuring safety.

[0051] In electric vehicles, SOH monitoring is used to assess the degradation of power battery packs, helping to predict remaining service life and optimize charging and discharging strategies. When SOH falls below 80%, battery capacity has significantly decreased and requires special attention. Accurate SOH monitoring can prevent sudden battery failures and improve driving safety.

[0052] The inventors discovered that as the battery is used, the stress between the cells gradually increases. Since the battery expands during use, some gas is generated in the cells. Therefore, the expansion force between the cells can be used to estimate the health status of the battery.

[0053] At the same time, operating power batteries within an optimal temperature range helps electric vehicles achieve optimal energy efficiency. Excessively high cell temperatures can shorten battery life and even cause thermal runaway, leading to cell combustion. Excessively low cell temperatures can reduce battery cycle life and charge / discharge capacity. The temperature of power batteries in new energy vehicles significantly impacts battery life and overall vehicle discharge efficiency. Therefore, real-time detection of cell temperature is crucial to ensuring battery safety.

[0054] Based on the above technical problems, some embodiments of the present application are to provide at least one first fiber Bragg grating (FBG) on the surface of each copper busbar. For each first fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively. Then, based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating, the fiber strain corresponding to each first fiber Bragg grating is determined, so as to determine the health status of the battery module based on the fiber strain. Among them, the first reflection wavelength change at the first measurement point can represent the fiber strain, but it is also affected by temperature. Therefore, the second reflection wavelength change can be used to directly represent the fiber temperature change, so that the first reflection wavelength change can be temperature compensated according to the second reflection wavelength change, effectively improving the accuracy of the fiber strain and further improving the accuracy of the battery SOH.

[0055] The following describes in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0056] The present application provides a battery monitoring method that can be applied to a battery module, such as Figure 1 As shown, the battery module 100 includes a cell connection system 102 and a plurality of cells 101. The cell connection system 102 includes a plurality of copper bars 106. Each copper bar is connected across a preset number of cells 101. At least one first fiber Bragg grating 103 is provided on the surface of each copper bar 106. Figure 2 As shown, each first fiber Bragg grating 103 includes a first sub-measurement point M ε and the second sub-point M T , where the first sub-point M ε and the second sub-point M T The distance L1 is less than the preset distance threshold.

[0057] like Figure 3 As shown, the method includes:

[0058] S101 , for each first fiber Bragg grating, measuring a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point.

[0059] The first reflection wavelength change and the second reflection wavelength change are both changes relative to the initial reflection wavelength of the first fiber grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point.

[0060] Optionally, the first measuring point is used to measure the strain of the fiber Bragg grating, and the second measuring point is used to measure the temperature change of the fiber Bragg grating. Since its strain is also affected by temperature, the first reflection wavelength change can be temperature compensated based on the second reflection wavelength change.

[0061] S102 : Determine the fiber strain corresponding to each first fiber Bragg grating based on the difference between the first reflection wavelength change amount and the second reflection wavelength change amount corresponding to each first fiber Bragg grating.

[0062] Among them, the optical fiber strain is used to characterize the expansion amplitude of the battery core.

[0063] Specifically, such as Figure 1 As shown, the battery module 100 may further include an optical fiber signal processor 105, which may determine the optical fiber strain corresponding to each first optical fiber Bragg grating based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first optical fiber Bragg grating.

[0064] Specifically, the first reflection wavelength change can be calculated and represented based on the following formula (1):

[0065] Δλ Bf / λ B0 =(1-P e )ε+(α L +α n )ΔT (1)

[0066] Where Δλ Bf is the change in the first reflection wavelength, λ B0 is the initial reflection wavelength, P e is the strain optical sensitivity coefficient, α L is the thermal expansion coefficient, α n is the optical sensitivity coefficient to temperature, ε is the optical fiber strain, and T is the temperature change.

[0067] The second reflected wavelength change can be calculated based on the following formula (2):

[0068] Δλ BT / λ B0 =(αL +α n )ΔT (2)

[0069] Where Δλ BT is the change in the second reflected wavelength.

[0070] The difference between the first reflected wavelength change and the second reflected wavelength change Δλ′ is Bf It can be calculated and characterized by the following formula:

[0071] Δλ′ Bf =Δλ Bf -Δλ BT (3)

[0072] Δλ′ Bf / λ B0 =(1-P e )ε (4)

[0073] The optical fiber strain ε can be calculated by formula (5):

[0074] ε=Δλ′ Bf / λ B0 (1-P e ) (5)

[0075] S103, determining the health status of the battery module based on the optical fiber strain.

[0076] Specifically, the health status of the battery module can be determined based on the optical fiber strain, battery charging status and battery internal resistance.

[0077] In an embodiment of the present application, at least one first fiber Bragg grating (FBG) is disposed on the surface of each copper busbar. For each first fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured. Then, based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating, the fiber strain corresponding to each first fiber Bragg grating is determined, thereby determining the health status of the battery module based on the fiber strain. The first reflection wavelength change at the first measurement point can represent the fiber strain, but it is also affected by temperature. Therefore, the second reflection wavelength change can be used to directly represent the fiber temperature change, so that the first reflection wavelength change is temperature compensated based on the second reflection wavelength change. This effectively improves the accuracy of the fiber strain and further improves the accuracy of the battery SOH.

[0078] A possible implementation method is provided in the embodiment of the present application, such as Figure 2 As shown, if two or more first fiber Bragg gratings are correspondingly provided on each copper busbar, the distance L2 between two adjacent first fiber Bragg gratings on the same copper busbar is a preset distance value.

[0079] Specifically, the distance between two adjacent first optical core gratings may be determined based on the cell crossover length of each copper busbar.

[0080] In an embodiment of the present application, two or more first fiber gratings can be set on each copper busbar, and each first fiber grating can be evenly arranged according to the cell crossover length of the corresponding copper busbar, which can effectively characterize the uniformity and effectiveness of the cell expansion of the battery module.

[0081] In an embodiment of the present application, a possible implementation method is provided, wherein the above-mentioned determination of the health status of the battery module based on the optical fiber strain includes:

[0082] S201 : Taking the average value of the optical fiber strain corresponding to each first optical fiber Bragg grating as the average strain.

[0083] S202 : Determine the health status of the battery module based on the mean strain variable.

[0084] In an embodiment of the present application, the mean value of the fiber strain corresponding to each first fiber grating can be used as the mean strain of the entire battery module to reflect the overall aging degree of the battery module based on the mean strain, which can further enhance the accuracy of the health status of the battery module.

[0085] In an embodiment of the present application, a possible implementation method is provided. For each first fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively, including:

[0086] If the optical fiber measurement signal is determined, for each first optical fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively.

[0087] In the embodiment of the present application, the measurement of the first fiber Bragg grating may be triggered by a fiber measurement signal, and the specific triggering steps will be described in detail below.

[0088] An embodiment of the present application provides a possible implementation method, wherein the above-mentioned determination of the optical fiber measurement signal is triggered based on any of the following conditions:

[0089] Obtain the measurement time interval of the battery module, if the measurement time interval is not less than the preset time interval;

[0090] The battery cell temperature of the battery module is obtained. If the battery cell temperature is greater than a preset temperature threshold, the optical fiber measurement signal is determined.

[0091] In some embodiments, the optical fiber measurement signal may be triggered based on a preset measurement time interval, for example, the optical fiber measurement signal may be triggered once every 30 days to implement regular detection of the battery module.

[0092] In other embodiments, the telecommunication temperature of the battery module can be monitored in real time. When the battery cell temperature is greater than a preset temperature threshold, an optical fiber measurement signal can be triggered to detect abnormal temperature of the battery module.

[0093] In some other embodiments, other signals of the battery module can also be monitored in real time to trigger the optical fiber measurement signal. The above other signals may include thermal runaway signals, abnormal charge state signals, etc., which are not specifically limited in the embodiments of the present application.

[0094] In an embodiment of the present application, a possible implementation method is provided. The battery module 100 further includes a plurality of second fiber Bragg gratings 104. The second fiber Bragg gratings 104 are arranged on a first surface of a target battery cell, on which a positive electrode column of the battery cell is arranged. The target battery cells are evenly spaced based on a preset number of battery cells.

[0095] The above method of obtaining the cell temperature of the battery module includes:

[0096] S301, measuring the change in the third reflection wavelength of each second fiber grating respectively.

[0097] S302: Determine a temperature change corresponding to the second fiber grating based on a third reflection wavelength change.

[0098] The expression of the third reflection wavelength variation in the second fiber Bragg grating is as follows:

[0099] Δλ / λ B0 =(α L +ξ)ΔT (6)

[0100] Among them, α L is the thermal expansion coefficient of the optical fiber, which indicates the relationship between the grating period and temperature change; ξ is the thermo-optical coefficient of the optical fiber, which indicates the rate of change of the refractive index with temperature; ΔT is the temperature change; λ B0 is the initial reflection wavelength, and Δλ is the change in the third reflection wavelength.

[0101] S303 , determining the cell temperature of the battery module based on the temperature change.

[0102] Specifically, the initial temperature of the battery module may be determined first, and then the cell temperature of the battery module may be determined based on the initial temperature and the temperature change. The specific cell temperature calculation method will be described in detail below.

[0103] In an embodiment of the present application, a possible implementation method is provided, wherein determining the cell temperature of the battery module based on the temperature change includes:

[0104] S401 : For each second fiber Bragg grating, obtain the corresponding initial reflected wave wavelength, and determine the initial temperature corresponding to the initial reflected wave wavelength.

[0105] The corresponding relationship between the initial reflected wave wavelength and the initial temperature can be determined based on the model of the second fiber grating, and then the initial temperature can be determined based on the corresponding relationship.

[0106] S402: Determine a temperature measurement value of each second fiber Bragg grating based on the initial temperature and the temperature variation corresponding to each second fiber Bragg grating.

[0107] Specifically, the sum of the initial temperature and the temperature change can be used as the temperature measurement value corresponding to the second fiber grating.

[0108] S403 : Determine the temperature of the battery cell of the battery module based on the temperature measurement value of each second fiber Bragg grating.

[0109] In some embodiments, the average of the temperature measurement values ​​of each second fiber Bragg grating can be used as the core temperature; in other embodiments, the extreme value of the temperature measurement value of each second fiber Bragg grating can also be used as the core temperature, which is not specifically limited in the embodiments of the present application.

[0110] In an embodiment of the present application, a possible implementation method is provided, wherein the above-mentioned determination of the battery cell temperature of the battery module based on the temperature measurement value of each second fiber Bragg grating includes:

[0111] If all temperature measurement values ​​are less than the preset temperature monitoring threshold, the average of the temperature measurement values ​​is taken as the battery cell temperature; if any temperature measurement value is not less than the temperature monitoring threshold, the maximum value of the temperature measurement values ​​is taken as the battery cell temperature.

[0112] In an embodiment of the present application, the temperature variation of each second fiber Bragg grating can be calculated to obtain a corresponding temperature measurement value. The temperature measurement values ​​of each second fiber Bragg grating can be sorted to obtain the battery cell temperature. When any temperature measurement value is not less than the temperature monitoring threshold, that is, there is an excessively large temperature measurement value, indicating that the battery is at a high risk of thermal runaway. The maximum value can be used as the battery cell temperature to facilitate thermal runaway management of the battery module. When all temperature measurement values ​​are less than the preset temperature monitoring threshold, the average of the temperature measurement values ​​can be used as the battery cell temperature. This embodiment of the present application allows for hierarchical management of the temperature measurement values, thereby improving the accuracy of the battery cell temperature.

[0113] An embodiment of the present application provides a possible implementation method, which includes: after determining the temperature measurement value of each second fiber Bragg grating, the following steps are performed:

[0114] S501 : Determine temperature distribution information of the battery module based on the temperature measurement value of each second fiber Bragg grating.

[0115] The temperature distribution information may be represented in the form of a temperature cloud map.

[0116] S502 : Determine a thermal management strategy for the battery module based on the temperature distribution information.

[0117] In an embodiment of the present application, the thermal management strategy of the battery module can be determined based on the temperature distribution information, the battery cells with abnormal temperatures can be quickly and intuitively located, and the targetedness of the thermal management strategy can be improved, effectively improving the user experience.

[0118] In order to better understand the above battery monitoring method, Figure 1 and Figure 4 An example of the battery monitoring method of the present application is described in detail, which can be applied to the battery module 100, such as Figure 1 As shown, the battery module 100 includes a cell connection system 102, a plurality of cells 101, a plurality of first fiber Bragg gratings 103 and a plurality of second fiber Bragg gratings 104 and an optical fiber signal processor 105. The cell connection system 102 includes a plurality of copper bars 106, each of which bridges a preset number of cells 101. At least one first fiber Bragg grating 103 is provided on the surface of each copper bar 106. Each first fiber Bragg grating 103 includes a first sub-measurement point M ε and the second sub-point M T , where the first sub-point M ε and the second sub-point M T The distance L1 is less than a preset distance threshold; the second fiber Bragg grating 104 is arranged on the first surface of a target battery cell, and a battery cell positive pole is arranged on the first surface; the target battery cells are evenly spaced based on a preset number of battery cells. The method includes the following steps:

[0119] S601, measuring the third reflection wavelength change of each second fiber Bragg grating respectively, determining the temperature change of the corresponding second fiber Bragg grating based on the third reflection wavelength change, and determining the battery core temperature of the battery module based on the temperature change.

[0120] S602: When the core temperature is greater than a preset temperature threshold, determine the optical fiber measurement signal.

[0121] S603 , in response to the optical fiber measurement signal, for each first optical fiber Bragg grating, respectively measure a first reflection wavelength change corresponding to the first sub-measurement point and a second reflection wavelength change corresponding to the second sub-measurement point.

[0122] The first reflection wavelength change and the second reflection wavelength change are both changes relative to the initial reflection wavelength of the first fiber grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point.

[0123] S604: Determine the fiber strain corresponding to each first fiber Bragg grating based on the difference between the first reflection wavelength change amount and the second reflection wavelength change amount corresponding to each first fiber Bragg grating.

[0124] Among them, the optical fiber strain is used to characterize the expansion amplitude of the battery core.

[0125] S605 , determining the health status of the battery module based on the optical fiber strain.

[0126] The present application provides a battery monitoring device, which is applied to a battery module. The battery module includes a cell connection system and a plurality of cells. The cell connection system includes a plurality of copper bars, each of which bridges a preset number of cells. At least one first fiber Bragg grating is provided on the surface of each copper bar. Each first fiber Bragg grating includes a first sub-measuring point and a second sub-measuring point. The distance between the first sub-measuring point and the second sub-measuring point is less than a preset threshold. Figure 5 As shown, the battery monitoring device 50 may include: a measurement module 501, a strain calculation module 502 and a health monitoring module 503;

[0127] The measurement module 501 is configured to measure, for each first fiber Bragg grating, a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point; wherein both the first reflection wavelength change and the second reflection wavelength change are changes relative to an initial reflection wavelength of the fiber Bragg grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point;

[0128] The strain calculation module 502 is configured to determine the fiber strain corresponding to each first fiber Bragg grating based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating; wherein the fiber strain is used to characterize the expansion amplitude of the core;

[0129] The health monitoring module 503 is used to determine the health status of the battery module based on the optical fiber strain.

[0130] A possible implementation method is provided in an embodiment of the present application. If two or more first fiber Bragg gratings are provided corresponding to each copper busbar, the distance between two adjacent first fiber Bragg gratings on the same copper busbar is a preset distance value.

[0131] In an embodiment of the present application, a possible implementation is provided. When determining the health status of the battery module based on the optical fiber strain, the health monitoring module 503 is configured to:

[0132] Taking the average value of the optical fiber strain corresponding to each first optical fiber Bragg grating as the average strain;

[0133] The health status of the battery module is determined based on the mean strain variable.

[0134] In an embodiment of the present application, a possible implementation is provided. When the measurement module 501 measures, for each first fiber Bragg grating, a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point, the measurement module 501 is configured to:

[0135] If the optical fiber measurement signal is determined, for each first optical fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively.

[0136] An embodiment of the present application provides a possible implementation method, wherein the above-mentioned determination of the optical fiber measurement signal is triggered based on any of the following conditions:

[0137] Obtain the measurement time interval of the battery module, if the measurement time interval is not less than the preset time interval;

[0138] The battery cell temperature of the battery module is obtained. If the battery cell temperature is greater than a preset temperature threshold, the optical fiber measurement signal is determined.

[0139] In an embodiment of the present application, a possible implementation method is provided. The battery module further includes a plurality of second fiber Bragg gratings, each of which is disposed on a first surface of a target battery cell, on which a positive electrode column of the battery cell is disposed. The target battery cells are evenly spaced based on a preset number of battery cells.

[0140] When obtaining the cell temperature of the battery module, the measurement module 501 is used to:

[0141] measuring the change of the third reflection wavelength of each fiber Bragg grating respectively;

[0142] Determining a temperature change of the corresponding second fiber grating based on a third reflection wavelength change;

[0143] The cell temperature of the battery module is determined based on the temperature change.

[0144] In an embodiment of the present application, a possible implementation is provided. When determining the cell temperature of the battery module based on the temperature variation, the measurement module 501 is configured to:

[0145] For each second fiber Bragg grating, obtaining a corresponding initial reflected wave wavelength, and determining an initial temperature corresponding to the initial reflected wave wavelength;

[0146] Determining a temperature measurement value of each second fiber Bragg grating based on an initial temperature and a temperature variation corresponding to each second fiber Bragg grating;

[0147] The temperature of the battery cell of the battery module is determined based on the temperature measurement value of each second fiber Bragg grating.

[0148] In an embodiment of the present application, a possible implementation is provided. When determining the temperature of the battery cell of the battery module based on the temperature measurement value of each second fiber Bragg grating, the measurement module 501 is configured to:

[0149] If all temperature measurement values ​​are less than the preset temperature monitoring threshold, the average of all temperature measurement values ​​is used as the battery cell temperature;

[0150] If any temperature measurement value is not less than the temperature monitoring threshold, the maximum value among the temperature measurement values ​​is taken as the battery cell temperature.

[0151] In an embodiment of the present application, a possible implementation is provided. After determining the temperature measurement value of each second fiber Bragg grating, the measurement module 501 is configured to:

[0152] Determining temperature distribution information of the battery module based on the temperature measurement value of each second fiber Bragg grating;

[0153] Determine the thermal management strategy of the battery module based on the temperature distribution information.

[0154] The device of the embodiment of the present application can execute the method provided by the embodiment of the present application, and its implementation principle is similar. The actions performed by each module in the device of each embodiment of the present application correspond to the steps in the method of each embodiment of the present application. For the detailed functional description of each module of the device, please refer to the description in the corresponding method shown in the previous text, and will not be repeated here.

[0155] In an embodiment of the present application, at least one first fiber Bragg grating (FBG) is disposed on the surface of each copper busbar. For each first fiber Bragg grating, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured. Then, based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating, the fiber strain corresponding to each first fiber Bragg grating is determined, thereby determining the health status of the battery module based on the fiber strain. The first reflection wavelength change at the first measurement point can represent the fiber strain, but it is also affected by temperature. Therefore, the second reflection wavelength change can be used to directly represent the fiber temperature change, so that the first reflection wavelength change is temperature compensated based on the second reflection wavelength change. This effectively improves the accuracy of the fiber strain and further improves the accuracy of the battery SOH.

[0156] In an embodiment of the present application, a battery module is provided, comprising a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of a battery monitoring method. Compared with the related art, the following can be achieved: the embodiment of the present application provides at least one first fiber Bragg grating (FBG) on the surface of each copper busbar. For each first fiber Bragg grating, a first reflection wavelength change corresponding to a first sub-measurement point and a second reflection wavelength change corresponding to a second sub-measurement point are measured respectively; then, based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each first fiber Bragg grating, the fiber strain corresponding to each first fiber Bragg grating is determined, so as to determine the health status of the battery module based on the fiber strain. Among them, the first reflection wavelength change at the first measuring point can represent the fiber strain, but it is also affected by temperature. Therefore, the second reflection wavelength change can be used to directly represent the fiber temperature change, so that the first reflection wavelength change is temperature compensated according to the second reflection wavelength change, effectively improving the accuracy of the fiber strain and further improving the accuracy of the battery state of health.

[0157] In an alternative embodiment, an electronic device is provided, such as Figure 6 As shown, Figure 6 The electronic device 60 shown includes: a processor 601 and a memory 603. The processor 601 and the memory 603 are connected, for example, via a bus 602. Optionally, the electronic device 60 may further include a transceiver 604, which can be used for data exchange between the electronic device and other electronic devices, such as data transmission and / or data reception. It should be noted that in actual applications, the number of transceivers 604 is not limited to one, and the structure of the electronic device 60 does not constitute a limitation on the embodiments of the present application.

[0158] The processor 601 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor 601 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0159] The bus 602 may include a path for transmitting information between the above components. The bus 602 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 602 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0160] The memory 603 can be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, other magnetic storage devices, or any other medium that can be used to carry or store computer programs and can be read by a computer, without limitation here.

[0161] The memory 603 is used to store the computer program for executing the embodiment of the present application, and the execution is controlled by the processor 601. The processor 601 is used to execute the computer program stored in the memory 603 to implement the steps shown in the above method embodiment.

[0162] The electronic devices include, but are not limited to, mobile terminals such as mobile phones, notebook computers, PADs, etc., and fixed terminals such as digital TVs, desktop computers, etc.

[0163] In an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method shown in the first aspect of the embodiment of the present application are implemented.

[0164] While the above description does not provide detailed technical details regarding the patterning of each layer, those skilled in the art will appreciate that various technical means can be employed to form layers, regions, and the like in desired shapes. Furthermore, those skilled in the art may devise methods that differ from those described above to achieve the same structure. Furthermore, while each embodiment has been described separately, this does not mean that the measures in each embodiment cannot be advantageously combined.

[0165] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0166] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A battery monitoring method, characterized in that: Applied to a battery module, the battery module includes a battery cell connection system and multiple battery cells, the battery cell connection system includes multiple copper bars, each of the copper bars spanning a preset number of battery cells, at least one first fiber Bragg grating (FBG) is provided on a surface of each copper bar, each of the first fiber Bragg grating (FBG) includes a first sub-measuring point and a second sub-measuring point, wherein the distance between the first sub-measuring point and the second sub-measuring point is less than a preset distance threshold, the method comprising: For each of the first fiber Bragg gratings, measuring a first reflection wavelength change corresponding to the first sub-measurement point and a second reflection wavelength change corresponding to the second sub-measurement point, respectively; wherein the first reflection wavelength change and the second reflection wavelength change are both changes relative to an initial reflection wavelength of the first fiber Bragg grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measurement point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measurement point; Determine the fiber strain corresponding to each of the first fiber Bragg gratings based on the difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each of the first fiber Bragg gratings; wherein the fiber strain is used to characterize the expansion amplitude of the core; The health status of the battery module is determined based on the optical fiber strain.

2. The method according to claim 1, characterized in that If two or more first optical fiber Bragg gratings are correspondingly provided for each of the copper busbars, the distance between two adjacent first optical fiber Bragg gratings on the same copper busbar is a preset distance value.

3. The method according to claim 1, characterized in that The determining the health status of the battery module based on the optical fiber strain includes: taking the average value of the optical fiber strain corresponding to each of the first optical fiber gratings as the average strain; A health state of the battery module is determined based on the mean strain.

4. The method according to claim 1, wherein The step of measuring, for each of the first fiber Bragg gratings, a first reflection wavelength change corresponding to the first sub-measurement point and a second reflection wavelength change corresponding to the second sub-measurement point, respectively, includes: If the optical fiber measurement signal is determined, for each of the first optical fiber Bragg gratings, the first reflection wavelength change corresponding to the first sub-measurement point and the second reflection wavelength change corresponding to the second sub-measurement point are measured respectively.

5. The method according to claim 4, characterized in that If the optical fiber measurement signal is determined, it is triggered based on any of the following conditions: Obtaining a measurement time interval of the battery module, if the measurement time interval is not less than a preset time interval; The battery cell temperature of the battery module is obtained, and if the battery cell temperature is greater than a preset temperature threshold, an optical fiber measurement signal is determined.

6. The method according to claim 5, characterized in that The battery module further includes a plurality of second fiber Bragg gratings, each of which is disposed on a first surface of a target battery cell, on which a positive electrode column of the battery cell is disposed; the target battery cells are evenly spaced based on a preset number of battery cells; The obtaining of the cell temperature of the battery module includes: respectively measuring a change in the third reflection wavelength of each of the second fiber gratings; Determining a temperature change corresponding to the second fiber grating based on the third reflection wavelength change; The battery cell temperature of the battery module is determined based on the temperature change.

7. The method according to claim 6, characterized in that The determining the cell temperature of the battery module based on the temperature change includes: For each of the second fiber Bragg gratings, obtaining a corresponding initial reflected wave wavelength, and determining an initial temperature corresponding to the initial reflected wave wavelength; Determining a temperature measurement value of each second fiber Bragg grating based on an initial temperature and a temperature change corresponding to each second fiber Bragg grating; The temperature of the battery cell of the battery module is determined based on the temperature measurement value of each second fiber Bragg grating.

8. The method according to claim 7, characterized in that The determining of the battery cell temperature of the battery module based on the temperature measurement value of each second fiber Bragg grating includes: If all the temperature measurement values ​​are less than the preset temperature monitoring threshold, the average of the temperature measurement values ​​is used as the battery core temperature; If any of the temperature measurement values ​​is not less than the temperature monitoring threshold, the maximum value among the temperature measurement values ​​is used as the battery core temperature.

9. The method according to claim 7, characterized in that After determining the temperature measurement value of each second fiber Bragg grating, the method further comprises: determining temperature distribution information of the battery module based on the temperature measurement value of each second fiber Bragg grating; A thermal management strategy for the battery module is determined based on the temperature distribution information.

10. A battery monitoring device, characterized in that: Applied to a battery module, the battery module includes a battery cell connection system and multiple battery cells, the battery cell connection system includes multiple copper bars, each of the copper bars spanning a preset number of battery cells, each of the copper bars is provided with at least one first fiber Bragg grating (FBG), each of the first fiber Bragg grating (FBG) includes a first sub-measuring point and a second sub-measuring point, wherein the distance between the first sub-measuring point and the second sub-measuring point is less than a preset threshold; the device includes: a measurement module configured to measure, for each of the first fiber Bragg gratings, a first reflection wavelength change corresponding to the first sub-measuring point and a second reflection wavelength change corresponding to the second sub-measuring point; wherein the first reflection wavelength change and the second reflection wavelength change are both changes relative to an initial reflection wavelength of the fiber Bragg grating; the first reflection wavelength change is positively correlated with the temperature and strain of the first sub-measuring point, and the second reflection wavelength change is positively correlated with the temperature of the second sub-measuring point; a strain calculation module, configured to determine the fiber strain corresponding to each of the first fiber Bragg gratings based on a difference between the first reflection wavelength change and the second reflection wavelength change corresponding to each of the first fiber Bragg gratings; wherein the fiber strain is used to characterize the expansion amplitude of the core; A health monitoring module is used to determine the health status of the battery module based on the optical fiber strain.

11. A battery module, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 9 when executing the computer program.

12. A storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 9 are implemented.

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