Fiber optic based sensing film

Abstract

This application discloses an optical fiber-based sensing film. According to an example, the optical fiber-based sensing film may include at least one optical fiber and a substrate. The at least one optical fiber may be integrated into the substrate. The substrate may include thickness and material properties specified to determine, via the at least one optical fiber and for a device, thermal and / or mechanical properties associated with the device or radiation levels associated with the device environment, wherein the device is continuously bonded to the surface of the substrate, including the substrate embedded in the device or including the surface of the substrate at a predetermined distance from the device.

Description

[0001] priority

[0002] This application claims priority to European Patent Application No. EP21305505.6, filed on April 16, 2021, entitled “OPTICAL FIBER-BASED SENSING MEMBRANE LAYOUT”, and European Patent Application No. EP21305506.4, filed on April 16, 2021, entitled “OPTICAL FIBER-BASED SENSING MEMBRANE”, the disclosures of which are hereby incorporated by reference in their entirety. background

[0003] Optical fibers can be used in various industries, such as communications, medical, military, and broadcasting, for data transmission and other related applications. Examples of applications can include sensing temperature, mechanical strain, vibration, and / or radiation dose using optical fibers. In this regard, the principles of Raman scattering, Rayleigh scattering, and / or Brillouin scattering can be implemented for sensing temperature, mechanical strain, vibration, and / or radiation dose. Summary of the Invention

[0004] In a first aspect, the present invention provides an optical fiber-based sensing film comprising: at least one optical fiber; and a substrate, wherein the at least one optical fiber is integrated in the substrate, the substrate comprising thickness and material properties, and the thickness and material properties being specified to determine, via the at least one optical fiber, at least one of thermal or mechanical properties associated with the device or a radiation level associated with the device environment, the device being: continuously coupled to a surface of the substrate, including the substrate embedded in the device, or including a surface of the substrate at a predetermined distance from the device.

[0005] Preferably, the device includes a battery pack for an electric vehicle.

[0006] Preferably, the mechanical properties include at least one of strain or vibration.

[0007] Preferably, the substrate comprises polyimide.

[0008] Preferably, at least one optical fiber and the substrate comprise approximately 200 g / m 2 Up to 500g / m 2 The combined weight between them.

[0009] Preferably, at least one optical fiber and the substrate have a combined thickness of less than about 0.5 mm.

[0010] Preferably, at least one optical fiber comprises a single optical fiber in a loop.

[0011] Preferably, the sensing film further includes a heat diffuser for transferring heat from areas of the device not monitored by the fiber-optic sensing film to areas monitored by the fiber-optic sensing film.

[0012] In a second aspect, the present invention provides an optical fiber-based sensing film comprising: at least one optical fiber; and a substrate, wherein the at least one optical fiber is integrated in the substrate, the substrate comprising thickness and material properties, and the thickness and material properties being specified to determine at least one of thermal or mechanical properties associated with a device via the at least one optical fiber.

[0013] Preferably, the device includes a battery pack for an electric vehicle.

[0014] Preferably, the substrate comprising at least one optical fiber is formed as a strip to be wrapped around the device.

[0015] Preferably, the substrate comprising at least one optical fiber is formed in a three-dimensional (3D) shape to at least partially surround the device.

[0016] In a third aspect, the present invention provides a method comprising: embedding an optical fiber-based sensing film in a device or continuously bonding an optical fiber-based sensing film to a device, wherein the optical fiber-based sensing film comprises: at least one optical fiber; and a substrate, wherein the at least one optical fiber is integrated in the substrate, and the substrate comprises thickness and material properties; and determining at least one of thermal or mechanical properties associated with the device via the embedded or continuously bonded optical fiber-based sensing film.

[0017] Preferably, the device includes a battery pack for an electric vehicle.

[0018] Preferably, the device includes a pouch battery module comprising at least one pouch that expands or contracts based on thermal changes within the pouch battery module, and wherein determining at least one of the thermal or mechanical properties associated with the device via an embedded or continuously coupled fiber-optic sensing film further includes determining the mechanical properties via the continuously coupled fiber-optic sensing film, the mechanical properties including strain based on the expansion of at least one pouch due to thermal changes associated with the device.

[0019] Preferably, the device includes a pouch battery module, the pouch battery module including at least one plate that expands based on thermal changes in the pouch battery module, and wherein determining at least one of the thermal or mechanical properties associated with the device via an embedded or continuously bonded fiber-optic sensing film further includes: determining the mechanical properties via a continuously bonded fiber-optic sensing film, the mechanical properties including strain based on the expansion of the at least one plate due to thermal changes associated with the device.

[0020] Preferably, at least one plate includes a curved profile.

[0021] Preferably, the device includes a pouch cell module, the pouch cell module including at least one piston that moves based on thermal changes in the pouch cell module, and wherein determining at least one of the thermal or mechanical properties associated with the device via an embedded or continuously coupled fiber-optic sensing film further includes determining the mechanical properties via the continuously coupled fiber-optic sensing film, the mechanical properties including strain based on the movement of at least one piston due to thermal changes associated with the device.

[0022] Preferably, determining the mechanical properties via a continuously bonded fiber-optic-based sensing film, including strain based on the movement of at least one piston caused by thermal changes associated with the device, further includes: determining the mechanical properties via a continuously bonded fiber-optic-based sensing film, the mechanical properties including strain based on the movement of at least one piston caused by the expansion of an associated soft package due to thermal changes associated with the device.

[0023] Preferably, the method further includes using a heat diffuser to transfer heat from an area of ​​the device not monitored by the fiber-optic sensing film to an area monitored by the fiber-optic sensing film. Brief description of the attached diagram

[0024] The features of this disclosure are illustrated by the examples shown in the figures below. In the figures below, similar numbers represent similar elements, where:

[0025] Figure 1 An example of an electric vehicle including an optical fiber-based sensing membrane is shown according to the present disclosure;

[0026] Figure 2 Examples according to this disclosure are shown. Figure 1 Electric vehicles in which the fiber-optic sensing film has been removed;

[0027] Figure 3 The example shown illustrates the use of this disclosure. Figure 1 A schematic diagram of a fiber-optic-based sensing film;

[0028] Figure 4 An example of a pre-cut membrane according to this disclosure is shown. Figure 1 A schematic diagram of a fiber-optic-based sensing film;

[0029] Figure 5An example of a ribbon configuration according to this disclosure is shown. Figure 1 A schematic diagram of a fiber-optic-based sensing film;

[0030] Figure 6 An example of a battery casing comprising a substrate is shown according to this disclosure. Figure 1 A schematic diagram of a fiber-optic-based sensing film;

[0031] Figure 7 An example of a pouch cell module according to the present disclosure is shown;

[0032] Figure 8 Examples according to this disclosure are shown. Figure 7 The normal and bulging states of the pouch battery module, and by utilizing Figure 1 Detection of bulging in pouch cell modules using fiber-optic sensing films or optical fibers;

[0033] Figure 9 and Figure 10 Variations of a pouch battery module according to an example of this disclosure are shown, as well as the method of utilizing... Figure 1 Other examples of fiber-optic based sensing films or fiber optic connections for detecting bulging in pouch cell modules; and

[0034] Figure 11 Examples of methods for use with this disclosure are shown. Figure 1 A thermal diffuser that utilizes fiber-optic sensing films together. Detailed description

[0035] For simplicity and illustrative purposes, this disclosure is described primarily by reference to examples thereof. Details are set forth in the following description to provide an understanding of this disclosure. However, it will be apparent that this disclosure may be practiced without limitation these details. In other instances, some methods and structures have not been described in detail to avoid unnecessarily obscuring this disclosure.

[0036] In this disclosure, the terms "a" and "an" are intended to mean at least one of a particular element. As used herein, the term "includes" means including but not limited to, and the term "including" means including but not limited to. The term "based on" means at least partially based on.

[0037] According to the examples disclosed herein, an optical fiber-based sensing film may include at least one optical fiber and a flexible substrate. The at least one optical fiber may be integrated into the flexible substrate. The flexible substrate may include thickness and material properties specified to determine the thermal and / or mechanical properties associated with the device via the at least one optical fiber, for devices continuously bonded to the surface of the flexible substrate, including flexible substrates embedded in devices or included on the surface of a flexible substrate at a predetermined distance from the device. Examples of mechanical properties may include strain, vibration, and other such properties. The device may include, for example, a battery pack for an electric vehicle, or any other type of flat or curved structure to be monitored. Applications may include, but are not limited to, monitoring of battery-based energy storage power plants, monitoring of nuclear power plants, and monitoring of defense devices. Furthermore, the substrate may be flexible or rigid. For example, for surface applications of the sensing film on a device or embedded applications of the sensing film in a device, the optical fiber may be embedded in a rigid sensing film formed from a rigid substrate. According to another example, for optical fibers integrated into molded components of a device such as a battery pack, the optical fiber may be embedded in a rigid sensing film formed from a rigid substrate.

[0038] In fiber optic sensing, fiber optics are typically used in some applications to monitor the thermal and / or mechanical characteristics of a device. The device, as used herein, can be any type of machine, component, structure, etc., to be monitored. For example, in devices such as battery packs for electric vehicles comprising a plurality of battery cells, fiber optics can be used to monitor the thermal and / or mechanical characteristics of the battery pack. In this respect, directly embedding fiber optics into the device may be impractical due to the technical challenges associated with laying, winding, and / or attaching optical connectors, for example, each time the individual components of the device (e.g., the battery cells of the battery pack) need to be handled.

[0039] To address at least the aforementioned technical challenges, the fiber-optic sensing film disclosed herein may include at least one optical fiber integrated into a flexible substrate. According to the examples disclosed herein, the fiber-optic sensing film may utilize, for example, a polyimide flex or other such materials. In this regard, the fiber-optic sensing film may also accommodate components such as an electrical track, a sensor, and an optical connector to reduce the electrical harness associated with the use of the fiber-optic sensing film.

[0040] Based on the examples disclosed herein, fiber-optic sensing films can include various types of layouts. For example, layouts can include single or multiple optical fibers, single-end or double-end access to the optical fibers, and other types of layouts. For instance, complete and perfect path folding can be achieved using multi-core optical fibers and loopback optics, with two cores connected in series at the far end of the interrogator.

[0041] Based on the examples disclosed herein, fiber-based sensing films may include fiber loops to compensate for spatial resolution. Alternatively or additionally, fiber-based sensing films may include path folds or partial path folds to compensate for fiber loss.

[0042] Based on the examples disclosed herein, fiber-optic sensing films can sense various types of parameters associated with a device. For example, parameters may include temperature, strain, vibration, radiation dose, and other such parameters.

[0043] Based on the examples disclosed herein, fiber-optic sensing films can enhance the ability to detect parameters that can be highly localized by transmitting parameters to the fiber location. For example, in detecting localized hotspots with a fiber loop structure, a heat diffuser can be applied to transfer heat to areas not covered by the fiber. Depending on the application constraints, a copper diffuser or a thermally conductive and electrically insulating material can be used.

[0044] Based on the examples disclosed herein, different types of parameters sensed by a fiber-optic sensing film can be used to generate different types of notifications or alarms. For example, a temperature change exceeding a specified temperature threshold can be used to generate a first type of notification or alarm. Similarly, a strain change exceeding a specified strain threshold (e.g., due to equipment damage) can be used to generate a second type of notification or alarm. The occurrence of thermal runaway in battery elements can also be classified by analyzing the time evolution, and particularly the rate of change of temperature or strain.

[0045] According to the examples disclosed herein, the number of components in the monitored device can be adjusted proportionally without the need for additional optical connectors. For example, the length or construction of the fiber-optic sensing film can be modified as needed to accommodate increases or decreases in the number of monitored components. In this respect, one or more optical connectors can be used for the fiber-optic sensing film, and the size of the fiber-optic sensing film can be increased or decreased as needed to accommodate multiple devices without requiring an optical connector for each device. Therefore, a single optical connection can be implemented for multiple monitored devices, thereby reducing the likelihood of malfunctions associated with the operation of the fiber-optic sensing film.

[0046] Based on the examples disclosed herein, the device being monitored can remain accessible, for example, for maintenance and other such activities, without being limited by the optics associated with the fiber-optic sensing film. For example, the fiber-optic sensing film can be configured to address a specific area of ​​the monitored device, while making other areas of the device available for maintenance and other activities.

[0047] Based on the examples disclosed herein, the fiber-optic sensing membrane itself can remain accessible, for example, for maintenance and other such activities. In this respect, the fiber-optic sensing membrane can be configured to address a specific area of ​​the monitored device, while other areas of the fiber-optic sensing membrane are available for maintenance and other activities.

[0048] Based on the examples disclosed herein, fiber-optic sensing films can be implemented in relatively harsh environments. For example, the environment for a fiber-optic sensing film can include a relatively significant temperature variation of approximately -40°C to 140°C. The material used for the sensing film can replace the standard fiber optic coating and continue to mechanically protect the fiber beyond the coating's melting point.

[0049] According to the examples disclosed herein, fiber-optic sensing films can include two-dimensional or three-dimensional configurations. Two-dimensional configurations can include multiple optical fibers embedded in a substrate and configured as a two-dimensional planar structure to match the corresponding two-dimensional surface of a device that will monitor temperature and / or strain changes, vibration and / or radiation dose. Three-dimensional configurations can include multiple optical fibers embedded in a substrate and configured as a three-dimensional structure to match the corresponding three-dimensional shape of a device that will monitor temperature and / or strain changes, vibration and / or radiation dose. Depending on the size of the structure to be monitored, the budget loss of the fiber optic system, and the dynamic range of the interrogator, the distance can be covered by a single chain or by multiple parallel optical fibers, which can be sequentially accessed from a single interrogator via an optical switch.

[0050] Based on the examples disclosed herein, fiber-optic sensing films can be used with optical time-domain reflectometers (OTDRs) to determine temperature, strain, and / or radiation dose associated with a device. An OTDR can represent an optoelectronic instrument used to characterize, for example, an optical fiber-based sensing film. An OTDR can inject a series of optical pulses into the fiber under test. Based on the injected optical pulses, the OTDR can extract light scattered or reflected back from points along the fiber from the same end where the pulses were injected. The re-converged scattered or reflected light can be used to characterize the fiber. For example, the re-converged scattered or reflected light can be used to detect, locate, and measure events at any location within the fiber. Events can include faults at any location within the fiber. Other types of characteristics that an OTDR can measure include attenuation uniformity and attenuation rate, segment length, and the location and insertion loss of connectors and splices.

[0051] OTDRs can be used to determine Brillouin and Rayleigh traces for optical fibers, such as those used for fiber-based sensing films. In one example, during initial acquisition, the Brillouin shift and Brillouin power can be used to establish an absolute reference for a Rayleigh reference trace (or more traces). The Rayleigh reference trace can represent a reference point for subsequent measurements using the Rayleigh shift. At this point, the absolute reference of the Rayleigh reference trace (or more traces) can then be used to determine the temperature and / or strain associated with the optical fiber by using the Brillouin and Rayleigh shifts in subsequent acquisitions.

[0052] According to the examples disclosed herein, fiber-optic sensing films can be used with OTDRs to determine temperature, strain, and / or vibration associated with devices such as battery packs based on distributed measurements.

[0053] According to the examples disclosed herein, an optical fiber-based sensing film may include at least one optical fiber and a substrate. The at least one optical fiber may be integrated into the substrate, and the substrate may include thickness and material properties. The thickness and material properties may be specified to determine the thermal and / or mechanical properties associated with the device or the radiation level associated with the device environment, via the at least one optical fiber and for a device continuously bonded to the surface of the substrate, including a substrate embedded in a device or a device comprising a surface of the substrate at a predetermined distance from the device.

[0054] For the fiber-optic-based sensing film described above, the device may include a battery pack for an electric vehicle.

[0055] For the fiber-optic-based sensing membrane described above, mechanical properties may include strain and / or vibration.

[0056] For the fiber-optic-based sensing film described above, the substrate may include polyimide.

[0057] For the fiber-optic sensing film described above, at least one optical fiber and the substrate can comprise approximately 200 g / m². 2 Up to 500g / m 2 The combined weight between them.

[0058] For the fiber-based sensing film described above, at least one fiber and the substrate may include a combined thickness of less than about 0.5 mm.

[0059] For the fiber-optic sensing film described above, at least one fiber may include a single fiber in a loop.

[0060] For the fiber-optic sensing film described above, the heat diffuser can transfer heat from areas of the device not monitored by the fiber-optic sensing film to areas monitored by the fiber-optic sensing film.

[0061] Based on the examples disclosed herein, an optical fiber-based sensing film may include at least one optical fiber and a substrate. The at least one optical fiber may be integrated into the substrate, and the substrate may include thickness and material properties. The thickness and material properties may be specified to determine the thermal and / or mechanical properties associated with the device via the at least one optical fiber.

[0062] For the fiber-optic sensing film described above, the substrate, including at least one fiber, can be formed as a strip to be wrapped around the device.

[0063] For the fiber-optic sensing film described above, the substrate, including at least one fiber, can be formed in a three-dimensional (3D) shape to at least partially surround the device.

[0064] According to the examples disclosed herein, a method may include embedding a fiber-optic sensing film in a device or continuously attaching a fiber-optic sensing film to a device. The fiber-optic sensing film may include at least one optical fiber and a substrate. The at least one optical fiber may be integrated into the substrate, and the substrate may include thickness and material properties. The method may also include determining thermal and / or mechanical properties associated with the device via the embedded or continuously attached fiber-optic sensing film.

[0065] For the methods described above, the device may include a pouch battery module comprising at least one pouch that expands or contracts based on thermal changes within the pouch battery module. In this regard, determining the thermal and / or mechanical properties associated with the device via an embedded or continuously coupled fiber-optic sensing film may also include determining the mechanical properties via a continuously coupled fiber-optic sensing film, the mechanical properties including strain based on the expansion of at least one pouch due to thermal changes associated with the device.

[0066] For the method described above, the device may include a pouch cell module comprising at least one plate that expands based on thermal changes within the pouch cell module. In this regard, determining the thermal and / or mechanical properties associated with the device via an embedded or continuously coupled fiber-optic sensing film may further include determining mechanical properties via a continuously coupled fiber-optic sensing film, the mechanical properties including strain based on the expansion of the at least one plate due to thermal changes associated with the device. The plate may include a curved profile.

[0067] For the method described above, the device may include a pouch battery module comprising at least one piston that moves based on thermal changes within the pouch battery module. In this regard, determining the thermal and / or mechanical characteristics associated with the device via an embedded or continuously coupled fiber-optic-based sensing film may further include determining the mechanical characteristics via the continuously coupled fiber-optic-based sensing film, the mechanical characteristics including strain based on the movement of at least one piston due to thermal changes associated with the device. In this regard, the mechanical characteristics may include strain based on the movement of at least one piston caused by the expansion of the associated pouch due to thermal changes associated with the device.

[0068] The method described above may further include using a heat diffuser to transfer heat from areas of the device not monitored by the fiber-optic sensing film to areas monitored by the fiber-optic sensing film.

[0069] Figure 1 An electric vehicle 100, including an optical fiber-based sensing film 102 (hereinafter referred to as "sensing film 102"), is shown as an example according to this disclosure. (See also...) Figure 1 The electric vehicle 100 may include a sensing membrane 102 disposed on a device such as a battery pack 104.

[0070] The electric vehicle 100 may include other known components, such as a thermal system 106 for cooling the vehicle, an auxiliary battery 108, an onboard battery charger 110, a vehicle transmission 112, a charging port 114 for a battery pack 104, a converter 116, a power electronic controller 118, and an electric traction motor 120.

[0071] Figure 2 Examples according to this disclosure are shown. Figure 1 An electric vehicle 100 in which the fiber-optic sensing film 102 has been removed.

[0072] Reference Figure 2 The diagram illustrates a battery pack 104 with the sensing membrane 102 removed. At this point, the battery pack 104 may include a plurality of battery cells 200 as shown. The sensing membrane 102 may be configured to sense changes in heat and / or strain, and / or vibration, associated with one, several, or all of the battery cells 200 of the battery pack 104.

[0073] Figure 3 A schematic diagram is shown illustrating an example of the use of an optical fiber-based sensing film 102 according to this disclosure.

[0074] Reference Figure 3 The fiber-optic sensing film 102 may include at least one optical fiber integrated into an adhesive substrate. Figure 3 In the example, as shown in the magnified view, multiple optical fibers 300 can be integrated into the adhesive substrate 302.

[0075] exist Figure 3 In the example, the sensing film can be Figure 3 The orientation is disposed on the upper and lower surfaces of the battery pack 104. The battery pack 104 may include a plurality of battery cells. In the example shown, the battery cells may be included in Figure 3 A cooling system 304 is provided between the upper and lower battery cells in the orientation. The upper and lower sensing films, as well as the battery pack 104, can be encapsulated in a housing, with the upper layer 306 and lower layer 308 of the housing... Figure 3 The orientation is shown.

[0076] for Figure 3 For example, the sensing film 102 at 310 can be used to sense the thermal and / or strain changes and / or vibrations of the upper battery cell at 312, and the sensing film 102 at 314 can be used to sense the thermal and / or strain changes and / or vibrations of the lower battery cell at 316.

[0077] The adhesive substrate may include polyimide or other such materials. The polyimide material can provide the necessary durability against vibrations associated with the battery pack 104 and / or other components that may be bonded to the sensing film 102. Similarly, the polyimide material can provide the necessary durability against temperature variations associated with the battery pack 104 and / or other components, which may be approximately -40°C to 140°C, or include a range larger than -40°C to 140°C. Furthermore, the polyimide material can provide the necessary flexibility associated with surface changes associated with the battery pack 104 and / or other components that may be bonded to the sensing film 102. The polyimide material may also be transparent, thus providing sufficient light transmission into the optical fiber for detecting light or anomalies associated with the battery pack 104 (e.g., high-temperature events).

[0078] The sensing membrane 102 can be lightweight (e.g., 200-500 g / m²). 2 In this respect, the sensing membrane 102 can add minimal weight to devices that monitor heat and / or strain changes and / or vibration.

[0079] The sensing film 102 can be approximately 0.5 mm thick, thus minimizing the integration challenges with respect to the monitored heat and / or strain changes and / or vibrations. In this regard, the thickness of the optical fiber embedded in the sensing film 102 can be approximately 0.25 mm. For optical fiber geometries including fiber crossings, such fibers can be treated after the sensing film is assembled, for example, by a combination of pressure and temperatures above the melting point of the fiber coating, without affecting the sensing film material. Therefore, the total thickness of 0.5 mm can thus increase the minimum thickness associated with the battery pack 104. The same process can be applied to reduce micro-bends applied to the optical fiber at each fiber crossing. The accumulation of thousands of micro-bends can induce attenuation.

[0080] Continue to refer to Figure 3 An example test setup is shown for evaluating the performance of a distributed temperature sensing system based on a distributed temperature sensing interrogator (DTS) 318 (also referred to herein as a distributed temperature sensor) and a fiber optic sensing film 320. This setup can be used to sense temperature, but a distributed strain sensing interrogator can also be used instead of the DTS to sense strain changes. In this regard, the distributed temperature sensing interrogator 318, which may include an OTDR, can be used with various examples of the sensing film 102 disclosed herein.

[0081] The sensing film 102 can provide monitoring of the entire surface of the battery pack 104. In this respect, the sensing film 102 can be formed to the required size to monitor part or the entire surface of the battery pack 104.

[0082] The sensing membrane 102 can be scalable to measure temperature and / or strain changes and / or vibrations associated with a group of cells. For example, multiple sensing membranes can be used to measure temperature and / or strain changes and / or vibrations associated with cells in a corresponding group.

[0083] The sensing membrane 102 can be similarly scalable to measure mechanical damage to the battery cells of the battery pack 104 and / or to the casing of the battery pack 104. At this point, any mechanical damage to the battery cells and / or casing exceeding a specified amount can be determined by the sensing membrane 102 as a strain change.

[0084] The sensing film 102 may be single-ended, including a single optical connector. In this respect, the single optical connector may be connected to a single optical fiber of the sensing film 102, wherein the single optical fiber may be constructed in various patterns, such as parallel to the loop, serrated, curved, etc., to cover the entire area of ​​the sensing film 102.

[0085] Figure 4 A schematic diagram of an optical fiber-based sensing membrane 102 including a pre-cut membrane, according to an example of the present disclosure, is shown.

[0086] refer to Figure 4 According to the examples disclosed herein, the sensing membrane 102 may include a plurality of pre-cut membranes 400 at one or more of its ends. Each pre-cut membrane may include an adhesive center 402 that can be removably secured to a region 404 or 406 of the battery 408. The battery 408 may be of the type used for electric vehicles and may include a planar region 410 and a raised region 412. Figure 4 In the example, the pre-cut film 400 can be staggered, such that when the sensing film 102 is laid onto the battery 408, the adhesive center is fixed to a region, such as region 404 or 406. For example, the pre-cut film 400 can be staggered to facilitate attachment to multiple optical fibers 414 looped at 416. The optical fibers 414 can, for example, be in… Figure 4 The optical fibers 414 are interconnected on the left-hand side, such that each fiber 414 is interconnected to form a sensing film 102. At this point, the entire battery 408 can be covered by a single fiber span including an optical connector. The sensing film 102 can include a relatively flat construction for easy storage. Furthermore, the relatively flat construction provides modular maintenance for the battery 408.

[0087] Figure 5 A schematic diagram of an optical fiber-based sensing film 102 comprising a strip structure, according to an example of the present disclosure, is shown.

[0088] refer to Figure 5 For the strip structure 500, the fiber-optic sensing film 102 can be wound around the battery 502 in a zigzag pattern as shown. For example, a single strip can be wound around four batteries in a zigzag pattern as shown.

[0089] Figure 6 A schematic diagram of an optical fiber-based sensing film 102 comprising a battery housing as a substrate, according to an example of the present disclosure, is shown.

[0090] refer to Figure 6 According to the examples disclosed herein, the fiber-optic sensing film 102 can utilize the battery housing as a substrate. In this respect, the fiber optic cable 600 can be adhered to or laminated to the surface of the battery housing cover 602 regardless of the material of the battery housing cover, or directly molded into the battery housing cover (in the case of a plastic or composite material battery housing cover).

[0091] Figure 7 An example of a pouch battery module according to the present disclosure is shown. Figure 8 Examples according to this disclosure are shown. Figure 7 The normal and bulging states of the pouch battery module, and the detection of the bulging of the pouch battery module using a sensing film 102 or an optical fiber. Figure 9 and Figure 10 The deformation of a pouch cell battery module according to an example of this disclosure is shown, as well as other examples of detecting the bulging of the pouch cell battery module by utilizing a sensing film 102 or an optical fiber.

[0092] Next reference Figures 7 to 9 Strain monitoring can allow the detection of gas generation in devices such as battery cells, and more specifically, pouch cell modules. Associated bulges in battery cells with internal pressure may be caused by faults, and early detection can prevent subsequent thermal escape. Regarding the sensing membrane 102, in one example, the optical fiber or fiber optic cable in the sensing membrane 102 may not be integrated during the battery cell assembly process and further within the device, such as the pouch cell module (avoiding optical connections entering and exiting the pouch cell module). In this respect, the sensing membrane 102 (or the optical fiber itself as disclosed herein) can be used to detect pressure outside the pouch cell module.

[0093] refer to Figure 7 Free space is available in some types of pouch cell modules (e.g., pouch cell module 700) that are heat-sealed and therefore narrower at three edges and possibly in two orthogonal dimensions. At this point, the sensing membrane 102 (or the optical fiber itself, as disclosed herein) can be used to measure pressure outside the pouch cell module 700. In one example, a liquid-filled pouch 702 can be placed in the free space between the pouch cells 704 of the pouch cell module 700. At this point, Figure 7 A cross-sectional view showing a pouch 702 (cut and full) and a pouch battery 704 (cut and full) is shown, each of which alternates in a pouch battery module 700.

[0094] like Figure 8 The diagram illustrates the pouch cell module 700 in its normal state at 800 and its bulging state at 802. The pouch cell can expand under pressure and protrude to the outside of the pouch cell module, for example, at 804, through a dedicated window 806 of the outer casing. At this point, a sensing film 102 (or the optical fiber itself, as disclosed herein) can be arranged at the dedicated window 806 to measure the strain from the expansion of the pouch cell.

[0095] In another example, such as Figure 9As shown, a pouch cell module 900 including pouch cells 902 may include a specifically profiled (e.g., curved) plate 904 placed in the free space between the pouch cells 902. In this case, lateral pressure on the plate 904 in the directions of arrows 906 and 908 (e.g., due to thermal expansion of the pouch cells 902) can cause the plate 904 to expand in the longitudinal direction at 908, so that it protrudes to the outside of the pouch cell module through a dedicated housing window 910. For the plate 904, an expansion of approximately 10% is achievable to allow movement on the order of centimeters. A sensing membrane 102 (or an optical fiber itself as disclosed herein) may be arranged at the dedicated window 910 to measure the strain from the expansion of the plate 904.

[0096] refer to Figure 10 , Figure 10 An example can achieve the following principle: the battery pouch alone can expand sufficiently to drive piston 1000 or any mechanism that protrudes to the outside of the pouch battery module 1002. Pouch 1004 can be optimized (e.g., including an enlarged region as shown) to enhance expansion at a target location to drive the desired movement and bending losses on the optical fiber of sensing film 102 (or the optical fiber itself, instead of sensing film 102 as disclosed herein). Therefore, when the pouch battery 1006 expands, pouch 1004 can similarly... Figure 10 The orientation expands upward to push the piston 1000 upward, wherein the strain induced in the optical fiber of the sensing film 102 (or the optical fiber itself, instead of the sensing film 102 as disclosed herein) can be sensed as disclosed herein. In the pouch cell... Figure 10 In the case of deformation from above, displacement can be used to press against a mechanical device installed in the cover of the pouch battery module.

[0097] for Figures 7 to 10 For example, the sensing membrane 102 or the optical fiber itself (e.g., without the sensing membrane 102 or in series after the sensing membrane 102) can be placed outside the soft package and in front of the pressure transmission component, as shown in the example. Figures 7 to 10The sensing film 102 is formed by a coating (e.g., a 900 μm buffer) surrounding the optical fiber, or the optical fiber including the coating (e.g., a 900 μm buffer) can be arranged in a polyimide ribbon and circulated throughout all pouch and pouch battery modules. In an example using the optical fiber itself, the optical fiber can be stranded in series after the sensing film 102, so that the optical fiber can be monitored using the same reflectometer that probes the sensing film 102. Protruding pressure on the pouch or plate can force the optical fiber (or sensing film 102) into a calibrated bend and will be detected as a loss on the reflection measurement trajectory. Different bend amounts can represent different loss types (e.g., a first bend amount can represent a first type of thermal event, a second bend amount can represent a second type of thermal event, etc.). Moderate spatial resolution on the OTDR can be used to detect which pouch battery module has a bulging pouch and take appropriate preventative action. Different preventative actions can correspond to different bend amounts.

[0098] Figure 11 An example of a thermal diffuser for use with an optical fiber-based sensing film 102, according to this disclosure, is shown.

[0099] refer to Figure 1 and Figure 11 The fiber-optic sensing film 102 can enhance the ability to detect parameters that can be highly localized by transmitting parameters to the fiber optic location. For example, in the case of detecting local hot spots with a fiber loop structure, a heat diffuser 1100 can be applied that is never exposed to the fiber (e.g., Figure 3 Heat is transferred over the area covered by the 300mm optical fiber. Depending on the application constraints, copper diffusers or thermally conductive and electrically insulating materials can be used.

[0100] The examples and variations thereof are described and illustrated herein. The terminology, descriptions, and figures used herein are illustrative only and are not intended to be limiting. Many variations are possible within the spirit and scope of this subject matter, which is intended to be defined by the appended claims and their equivalents, wherein all terms are used in their broadest reasonable sense unless otherwise stated.

Claims

1. An apparatus comprising: The fiber-optic sensing film comprises: At least one optical fiber and a substrate, wherein the at least one optical fiber is integrated in the substrate; and A pouch battery module includes a window, pouch batteries, and a curved plate disposed in the space between the pouch batteries, wherein, based on thermal changes within the pouch battery module, the pouch batteries expand to exert pressure on the plate, causing the plate to expand and protrude beyond the window of the pouch battery module. In this embodiment, at least one optical fiber of the fiber-based sensing film is arranged at the window of the pouch cell module to detect the expansion of the plate and to measure the mechanical properties of the device, including strain, based on the expansion of the plate.

2. The device according to claim 1, wherein, The device includes a battery pack for electric vehicles.

3. The device according to claim 1, wherein, The substrate comprises polyimide.

4. The device according to claim 1, wherein, The substrate includes a specified thickness and specified material properties to determine the strain associated with the device via at least one optical fiber of the fiber-based sensing film.

5. The device according to claim 1, wherein, The at least one optical fiber and the substrate comprise a combined thickness of less than approximately 0.5 mm.

6. The device according to claim 1, wherein, The at least one optical fiber includes a single optical fiber in a loop.

7. The device of claim 6 further includes a heat diffuser for transferring heat from a region of the device not monitored by the fiber-optic sensing film to a region monitored by the fiber-optic sensing film.

8. An apparatus comprising: The fiber-optic sensing film comprises: At least one optical fiber and a substrate, wherein the at least one optical fiber is integrated in the substrate; and A pouch battery module includes a window, a pouch, and a piston positioned between the pouch and the window, wherein, based on thermal changes within the pouch battery module, the pouch expands, and the expansion of the pouch pushes the piston to protrude beyond the window of the pouch battery module. In this embodiment, at least one optical fiber of the fiber-based sensing film is arranged at the window of the pouch cell module to detect the piston's movement and to measure the device's mechanical properties, including strain, based on the piston's movement.

9. The device according to claim 8, wherein, The device includes a battery pack for electric vehicles.

10. The device according to claim 8, wherein, The substrate, including the at least one optical fiber, is formed as a strip to be wrapped around the device.

11. The device according to claim 8, wherein, The substrate, including the at least one optical fiber, is formed in a three-dimensional (3D) shape to at least partially surround the device.

12. A method comprising: The fiber-based sensing film is embedded in the device or continuously coupled to the device, wherein the fiber-based sensing film comprises: at least one optical fiber and a substrate, wherein the at least one optical fiber is integrated in the substrate; A pouch battery module is provided, the pouch battery module including a window, pouch batteries, and a curved plate disposed in a space between the pouch batteries, such that, based on thermal changes in the pouch battery module, the pouch batteries expand to exert pressure on the plate, and the plate expands and protrudes beyond the window of the pouch battery module; and At least one optical fiber of the fiber-based sensing film is arranged at the window of the pouch cell module to detect the expansion of the plate and to measure mechanical properties, including strain, associated with the device based on the expansion of the plate.

13. The method according to claim 12, wherein, The device includes a battery pack for electric vehicles.

14. The method of claim 12, further comprising: The thermal characteristics of the device are determined based on the expansion of the plate via at least one optical fiber of the fiber-optic sensing film.

15. The method of claim 12, further comprising: A heat diffuser is used to transfer heat from areas of the device not monitored by the fiber-optic sensing film to areas monitored by the fiber-optic sensing film.

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