Fiber optic sensor, measurement apparatus, battery, battery system and measurement system

Abstract

A fiber optic sensor, a measurement apparatus, a battery, a battery system, and a measurement system. The fiber optic sensor comprises: an optical fiber and a plurality of sub-sensors, the plurality of sub-sensors being successively arranged in a fiber core of the optical fiber in the extension direction of the optical fiber, and the sub-sensors being used for measuring temperature and / or strain at corresponding positions. Each sub-sensor can measure the temperature and / or strain, such that the temperature and / or strain at multiple positions can be measured by one fiber optic sensor, allowing temperature and strain measurement processes to be simpler and more efficient.

Description

Fiber optic sensors, detection devices, batteries, battery systems, and detection systems

[0001] This application claims priority to Chinese Patent Application No. 202411001261.5, filed on July 25, 2024, entitled "Fiber Optic Sensor, Detection Device, Battery, Battery System and Detection System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a fiber optic sensor, a detection device, a battery, a battery system, and a detection system. Background Technology

[0003] During product use, temperature and strain can affect battery performance, so it is necessary to monitor the product's temperature and strain. For example, temperature and strain during charging and discharging can affect battery performance.

[0004] Currently, multiple sensors are required to detect temperature and strain at multiple locations, which results in a cumbersome detection process. Summary of the Invention

[0005] This application provides a fiber optic sensor, a detection device, a battery, a battery system, and a detection system that solve the problem of cumbersome current temperature and strain detection processes.

[0006] The first aspect of this application provides an optical fiber sensor, including: an optical fiber and a plurality of sub-sensors, wherein the plurality of sub-sensors are arranged sequentially in the core of the optical fiber along the extension direction of the optical fiber; the sub-sensors are used to detect temperature and / or strain at corresponding locations.

[0007] In one alternative embodiment, the sub-sensor receives target light within a corresponding wavelength range, and different sub-sensors receive target light within different wavelength ranges.

[0008] In one optional embodiment, the sub-sensor includes: a fiber Bragg grating sensor unit and a Fabry-Perot cavity sensor unit; the Fabry-Perot cavity sensor unit is located in the optical path of the transmitted light of the fiber Bragg grating sensor unit.

[0009] In one alternative embodiment, the optical fiber further includes a cladding that covers the fiber core.

[0010] A second aspect of this application provides a detection device connected to an optical fiber sensor according to any one of the first aspects. The detection device is used to: determine the temperature and / or strain of a target object detected by the sub-sensor based on reflected light and / or multiple beams returned by the sub-sensor based on incident target light.

[0011] In one alternative embodiment, determining the temperature and / or strain of the target object detected by the sub-sensor based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light includes: demodulating the multiple beams returned by the sub-sensor based on the incident target light to obtain the phase difference between adjacent beams in the multiple beams; and determining the strain based on the phase difference.

[0012] In one alternative embodiment, determining the temperature and / or strain of the target object detected by the sub-sensor based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light includes: demodulating the reflected light and multiple beams returned by the sub-sensor based on the incident target light to obtain the wavelength of the reflected light and the phase difference between adjacent beams in the multiple beams; and determining the temperature based on the phase difference, the wavelength of the reflected light, and the wavelength of the target light.

[0013] In one optional embodiment, the detection device is further configured to: determine the maximum temperature detected by the plurality of sub-sensors as the temperature of the corresponding target object; and / or determine the maximum strain detected by the plurality of sub-sensors as the strain of the corresponding target object.

[0014] A third aspect of this application provides a battery, including: a battery pack and at least one fiber optic sensor according to the first aspect, wherein the fiber optic sensor is disposed on the inner surface and / or outer surface of the battery pack.

[0015] In one alternative embodiment, the battery pack includes at least one battery cell, and the fiber optic sensor includes multiple sub-sensors, which are correspondingly disposed on the inner and / or outer surfaces of the battery cell. The sub-sensors are used to detect the temperature and / or strain of the corresponding battery cell.

[0016] In one alternative embodiment, the sub-sensor is attached to the inner and / or outer surface of the battery cell.

[0017] In one alternative embodiment, there are multiple fiber optic sensors, with different fiber optic sensors positioned at different locations within the battery pack.

[0018] A fourth aspect of this application provides a battery system, comprising: a detection device according to any of the second aspects and a battery according to any of the third aspects, wherein the detection device is connected to an optical fiber sensor on the battery, and the detection device is configured to: determine the temperature and / or strain of a corresponding battery cell based on reflected light and / or multiple beams returned by a sub-sensor based on incident target light.

[0019] In one alternative embodiment, the detection device is further configured to: determine the lithium plating state of the battery cell based on the strain of the battery cell.

[0020] In one optional embodiment, determining the lithium plating state of a battery cell based on its strain includes: determining the current strain amplitude of the battery cell based on the maximum and minimum strain detected during the current battery charging process; obtaining the historical strain amplitude of the battery cell during multiple historical charge-discharge processes; determining the trend of strain amplitude change based on multiple historical strain amplitudes and the current strain amplitude; and determining the lithium plating state based on the inflection point if there is an inflection point in the trend.

[0021] In one optional embodiment, the detection device is further configured to: determine the state of the battery cell based on the temperature and / or strain of the battery cell; and output a warning message when the state of the battery cell is abnormal.

[0022] In one optional embodiment, determining the state of a battery cell based on its temperature and / or strain includes: if the strain is greater than a strain threshold and / or the temperature is greater than a temperature threshold, determining that the state of the battery cell corresponding to the sub-sensor is an abnormal state.

[0023] In one alternative embodiment, the detection device is a battery management system.

[0024] The fifth aspect of this application provides a detection system, including an optical fiber sensor according to any one of the first aspects and a detection device according to any one of the second aspects, wherein the detection device is connected to the optical fiber sensor.

[0025] The sixth aspect of this application provides a detection method applied to the detection apparatus of any of the second aspects. The detection method includes: determining the temperature and / or strain of a corresponding target object based on reflected light and / or multiple beams returned by a sub-sensor based on incident target light.

[0026] A seventh aspect of this application provides a vehicle, the vehicle including: a battery system according to any one of the fourth aspects above.

[0027] The eighth aspect of this application provides an electronic device, including: a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the detection method of the sixth aspect.

[0028] The ninth aspect of this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the detection method of the sixth aspect.

[0029] The tenth aspect of this application provides a computer program product, the program product comprising: a computer program stored in a readable storage medium, at least one processor of an electronic device being able to read the computer program from the readable storage medium, and the at least one processor executing the computer program causing the electronic device to perform the detection method of the sixth aspect.

[0030] This application is applied to temperature and / or strain detection scenarios. The fiber optic sensor provided in this application includes an optical fiber and multiple sub-sensors, which are sequentially arranged along the fiber's extension direction within the fiber core. Each sub-sensor can detect temperature and / or strain at a corresponding location. Each sub-sensor in this application can detect temperature and / or strain, thus enabling the detection of temperature and / or strain at multiple locations using a single fiber optic sensor, making the temperature and strain detection process simpler and more efficient. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 is a schematic diagram of an optical fiber sensor provided in an exemplary embodiment of this application;

[0033] Figure 2 is a schematic diagram of a battery system provided by an exemplary embodiment of this application;

[0034] Figure 3 is a schematic diagram of a battery provided in an exemplary embodiment of this application;

[0035] Figure 4 is a schematic diagram of another battery system provided by an exemplary embodiment of this application;

[0036] Figure 5 is a graph showing the variation trend of strain amplitude provided by an exemplary embodiment of this application;

[0037] Figure 6 is another trend diagram of strain amplitude and SOH provided by an exemplary embodiment of this application;

[0038] Figure 7 is a microscopic image of lithium plating characteristics before and after an inflection point provided by an exemplary embodiment of this application;

[0039] Figure 8 is a schematic diagram of strain changing over time according to an exemplary embodiment of this application;

[0040] Figure 9 is a schematic diagram of the structure of an electronic device provided by an exemplary embodiment of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Within the existing energy framework, the foreseeable depletion of fossil fuels increasingly clashes with the environmental themes of modern society. The demand for pure electric power to replace fossil fuel-powered energy sources is becoming increasingly apparent in various scenarios. The discovery of lithium iron phosphate and ternary materials has made lithium-ion batteries the most widely used power storage device of this century.

[0043] However, battery performance can be affected by temperature and / or strain during use. One related technology involves placing and fixing a fiber Bragg grating sensor (FBG sensor) on the outer layer of the battery cell after it has been wound, stacked, and pressurized inside the battery. The FBG sensor is used to measure the internal state of the battery. However, this method involves implanting two FBG sensors inside the battery for temperature compensation, which presents a cumbersome detection process. Another method involves providing two fiber optic sensors. The surface of the first fiber optic sensor is deposited with the same metal material as the electrode to be tested, and the surface of the second fiber optic sensor is covered with a protective sleeve. The other ends of the first and second fiber optic sensors are passed through an aluminum-plastic film on the lithium battery and extend out of the film to connect to the demodulation system. Electrolyte is injected into the aluminum-plastic film. The demodulation system acquires the detection signals from the first and second fiber optic sensors respectively, and obtains the lithium metal stress signal. The lithium metal growth state in the lithium battery is analyzed based on the measured electrochemical test signal and the lithium metal stress signal. This method also requires two fiber optic sensors for processing and temperature compensation to obtain the stress signal, and it also has the problem of cumbersome operation.

[0044] To address the aforementioned issues, this application provides an optical fiber sensor comprising multiple sub-sensors arranged sequentially along the fiber's extension direction within the fiber core. Each sub-sensor can detect temperature and / or strain at a corresponding location. Each sub-sensor in this application can detect temperature and / or strain, thus enabling the detection of temperature and / or strain at multiple locations using a single optical fiber sensor, simplifying and simplifying the temperature and strain detection process.

[0045] Referring to Figure 1, which is a schematic diagram of an optical fiber sensor provided in this application, the optical fiber sensor includes: an optical fiber and multiple sub-sensors, the multiple sub-sensors being arranged sequentially in the core of the optical fiber along the extension direction of the optical fiber; the sub-sensors are used to detect temperature and / or strain at corresponding locations.

[0046] Each sub-sensor has the function of detecting temperature and strain at its corresponding location. In actual use, the sub-sensors can be configured to detect temperature and / or strain.

[0047] In the embodiments of this application, the fiber optic sensor can detect temperature and / or strain at multiple locations, making the detection process simple and cost-effective.

[0048] For example, sub-sensor a1 detects temperature, sub-sensor a2 detects temperature and strain, sub-sensor a3 detects strain, sub-sensor a4 detects temperature and strain, sub-sensor a5 detects temperature, and sub-sensor a6 detects temperature and strain. Alternatively, sub-sensors a1 through a6 may all detect temperature and strain.

[0049] Furthermore, each sub-sensor receives target light within a corresponding wavelength range, and different sub-sensors receive different wavelength ranges of target light. The wavelength range of the target light received by a sub-sensor is determined by its structure, which is pre-formed; therefore, the wavelength range corresponding to each sub-sensor is fixed during use. For example, referring to Figure 1, the light source emits broadband light to the fiber optic sensor, with a wavelength of 1500nm-1600nm. Sub-sensor a1 only receives target light with a wavelength range of 1510nm-1590nm, sub-sensor a2 only receives target light with a wavelength range of 1515nm-1580nm, and sub-sensor a3 only receives target light with a wavelength range of 1520nm-1570nm.

[0050] In the embodiments of this application, different sub-sensors are configured to receive target light with different wavelength ranges.

[0051] In one embodiment, the wavelength range of the sub-sensor positioned before the optical fiber in the optical path can be greater than the wavelength range of the sub-sensor positioned after the optical fiber in the optical path. This allows light to pass through one sub-sensor and then into the next sub-sensor. For example, if a wide beam of light enters from one side of sub-sensor a1 (as shown on the left side of sub-sensor a1 in Figure 1), and sub-sensor a1 transmits light with a wavelength range of 1510nm-1590nm, it can then be incident on the next sub-sensor a2. Similarly, light can be incident on the sub-sensor positioned at the end of the optical path in the optical fiber.

[0052] In this embodiment, the sub-sensor receives target light within a corresponding wavelength range. Different sub-sensors receive target light within different wavelength ranges, which can reflect a broadband light, allowing different sub-sensors to receive the corresponding target light.

[0053] In this embodiment, the sub-sensor includes a fiber Bragg grating sensor unit and a Fabry-Perot cavity sensor unit; the Fabry-Perot cavity sensor unit is located in the optical path of the transmitted light of the fiber Bragg grating sensor unit.

[0054] In this process, the target light from the sub-sensor is incident on the fiber Bragg grating sensor unit and then reflected to obtain reflected light and transmitted light; the Fabry-Perot cavity sensor unit is located in the optical path of the transmitted light from the fiber Bragg grating sensor unit, and the transmitted light is reflected and / or transmitted through the Fabry-Perot cavity sensor unit to obtain multiple beams.

[0055] Among them, the wavelength of the reflected light is related to the temperature and strain of the object detected by the sub-sensor; the phase difference between adjacent beams is related to the strain of the object.

[0056] In this embodiment, by setting up a fiber optic grating sensor unit and a Fabry-Perot cavity sensor unit, a single sub-sensor can be used to obtain temperature and strain simultaneously. Furthermore, based on Hooke's theorem, the corresponding stress and expansion force can be calculated from the strain.

[0057] Among them, the fiber optic sensor uses Bragg fiber, which does not require packaging.

[0058] In this embodiment, the fiber Bragg grating sensor unit includes multiple gratings, which can be etched using a femtosecond laser. The distance between adjacent gratings can be preset according to detection requirements, and the grating skewness can also be preset according to detection requirements; these are not limited. Furthermore, the length L of the Fabry-Perot cavity sensor unit can also be preset according to detection requirements.

[0059] The sub-sensor is used to detect the temperature and / or strain at the location of the object on which the sub-sensor is located. The object detected by the sub-sensor can be any object that requires temperature and / or strain detection, such as a battery, and is not limited thereto.

[0060] For example, in Figure 1, the fiber optic sensor X1 includes sub-sensors a1 to a6. Furthermore, the fiber includes a core, in which the sub-sensors are disposed. The fiber optic grating sensor unit consists of an optical fiber and a grating, with the grating being the core of the unit. The grating has the function of optically induced periodic modulation of the refractive index. The wavelength λ1 of the reflected light from the fiber optic grating sensor unit is related to the core mode index n. effAnd it is related to the grating period (Λ). When the target fiber incident on the fiber optic grating sensor unit is emitted by a wide-spectrum light source, the spectrum of the reflected light exhibits a spike, which is caused by grating interference. Furthermore, the working principle of the fiber optic grating sensor unit can be expressed by formula (1): λ1=2n eff Formula (1)

[0061] When the fiber Bragg grating sensor unit is affected by temperature and strain, it will affect n. eff The change in the value of Λ will affect the wavelength λ1 of the reflected light, so the wavelength λ1 of the reflected light can be used to characterize temperature and strain.

[0062] Furthermore, since the fiber Bragg grating sensor unit is simultaneously affected by temperature and strain, the wavelength λ1 of the reflected light changes, making it impossible to obtain a single parameter (either temperature or strain has a single effect on the wavelength λ1 of the reflected light). Based on this, referring to Figure 1, this application sets a Fabry-Perot cavity sensor unit on an optical fiber, so that the transmitted light from the fiber Bragg grating sensor unit is incident on the Fabry-Perot cavity sensor unit, generating reflection and transmission within the Fabry-Perot cavity sensor unit, resulting in multiple light beams, wherein reflection produces multiple reflected beams and transmission produces multiple transmitted beams.

[0063] The optical phase difference, occurring between two adjacent reflected or transmitted beams, describes the reflection or transmission spectrum. The phase difference between the reflected or transmitted beams of this Fabry-Perot cavity sensor unit can be determined according to formula (2):

[0064] In formula (2), δ represents the phase difference between adjacent beams, L represents the length of the Fabry-Perot cavity sensor unit, and n is a positive integer. Strain affects the value of L, which in turn affects the value of the phase difference δ. Therefore, the strain can be determined based on the phase difference δ.

[0065] Furthermore, this application does not limit the fabrication location of the Fabry-Perot cavity sensor unit. This application enables the design of multiple discrete sub-sensors on a single optical fiber, where the discrete sub-sensors are sequentially fiber optic grating sensor units and Fabry-Perot cavity sensor units. Moreover, the optical fiber can be fabricated using different design methods, such as micro / nano fabrication, chemical etching, and thin film deposition techniques, and this application does not limit its application in this regard.

[0066] Furthermore, the optical fiber also includes a cladding layer, which is used to cover the fiber core. The cladding layer possesses high strength, corrosion resistance, and high temperature resistance, thus protecting the sub-sensors.

[0067] This application enables the detection of temperature and strain using a single fiber optic sensor, making the temperature and strain detection process simpler and more efficient.

[0068] This application embodiment also provides a detection device, which is connected to the above-mentioned fiber optic sensor. The detection device is used to: determine the temperature and / or strain of the target object detected by the sub-sensor based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light.

[0069] Specifically, during battery charging or discharging, the detection device controls the light source to emit target light towards the sub-sensor.

[0070] In this embodiment, the detection device is connected to the light source. The detection device can control the light source to emit a wide beam of light to the sub-sensor. The sub-sensor receives the target light that matches the wavelength range of the wide beam of light according to its own receivable wavelength range.

[0071] The detection device then acquires the reflected light and / or multiple beams returned by the sub-sensor based on the target light.

[0072] Among them, the reflected light is obtained by the fiber optic grating sensor unit reflecting the target light after being affected by temperature and strain, and the multiple beams are obtained by the Fabry-Perot cavity sensor unit reflecting or refracting the transmitted light after being affected by strain.

[0073] Specifically, referring to the above-described sub-sensor embodiment, the detection device acquires the reflected light returned by the fiber Bragg grating sensor unit of the sub-sensor and multiple beams returned by the Fabry-Perot cavity sensor unit of the sub-sensor. Further, the detection device demodulates the acquired reflected light and / or multiple beams to obtain the temperature and strain of the battery cell corresponding to the sub-sensor.

[0074] In the embodiments of this application, the detection device, in conjunction with the fiber optic sensor, can determine the temperature and / or strain at multiple locations.

[0075] In one embodiment, determining the temperature and / or strain of the target object detected by the sub-sensor based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light includes: demodulating the multiple beams returned by the sub-sensor based on the incident target light to obtain the phase difference between adjacent beams in the multiple beams; and determining the strain based on the phase difference.

[0076] In this embodiment, the strain at the corresponding position of the sub-sensor can be determined by the Fabry-Perot cavity sensor unit.

[0077] In this embodiment, a first calibration parameter can be predetermined, which represents the correspondence between phase difference and strain. Then, during demodulation, the strain can be determined based on the first calibration parameter and the determined phase difference.

[0078] In another embodiment, determining the temperature and / or strain of the target object detected by the sub-sensor based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light includes: demodulating the reflected light and multiple beams returned by the sub-sensor based on the incident target light to obtain the wavelength of the reflected light and the phase difference between adjacent beams in the multiple beams; and determining the temperature based on the phase difference, the wavelength of the reflected light, and the wavelength of the target light.

[0079] Specifically, the phase difference and wavelength can be decoupled to determine the temperature at the sub-sensor.

[0080] In this embodiment, a second calibration parameter is predetermined, which represents the correspondence between phase difference, wavelength offset, and temperature. During demodulation, the wavelength offset between the reflected light and the target light is first determined, and then the temperature is determined based on the second calibration parameter, the wavelength offset, and the phase difference.

[0081] It can be understood that the demodulation process decouples the wavelength of the reflected light from multiple beams to remove the influence of strain on the wavelength of the reflected light, thereby obtaining the influence of temperature on the wavelength of the reflected light and determining the detected temperature.

[0082] Furthermore, the detection device is also used to: determine the maximum temperature detected by the multiple sub-sensors as the temperature of the corresponding target object; and / or determine the maximum strain detected by the multiple sub-sensors as the strain of the corresponding target object.

[0083] In this embodiment of the application, if multiple sub-sensors are provided on the target object, it can be understood that the maximum temperature and the maximum strain have a significant impact on the target object. Therefore, the maximum temperature detected by the multiple sub-sensors is determined as the temperature of the target object, and the maximum strain detected by the multiple sub-sensors is determined as the strain of the target object.

[0084] For example, referring to FIG2, if the target object is a battery cell, if a sub-sensor is provided on the inner surface and / or outer surface of the battery cell, the temperature calculated based on the sub-sensor is the temperature of the battery cell, and the strain calculated based on the sub-sensor is the strain of the battery cell.

[0085] Referring to Figures 3 and 4, if multiple sub-sensors are installed on the inner and / or outer surfaces of a battery cell, and each sub-sensor can calculate the corresponding temperature and strain, then the maximum temperature detected by the multiple sub-sensors can be determined as the temperature of the battery cell, and the maximum strain detected by the multiple sub-sensors can be determined as the strain of the battery cell. As shown in Figure 3, battery cell c1 corresponds to sub-sensors a1 and a2. Using the above method, sub-sensor a1 detects the temperature t1 and strain ε1, and sub-sensor a2 detects the temperature t2 and strain ε2. If t1 is greater than t2 and ε1 is less than ε2, then the temperature of battery cell c1 is t1, and the strain of battery cell c1 is ε2.

[0086] In the embodiments of this application, by setting multiple sub-sensors, the accuracy of the obtained temperature and / or strain can be improved.

[0087] In the embodiments of this application, when the target object corresponds to multiple sub-sensors, it is also possible to pre-set that the temperature detected by one of the sub-sensors is the temperature of the target object, and the strain detected by one of the sub-sensors is the strain of the target object.

[0088] The detection device provided in this application can obtain the temperature and strain of the target object based on the aforementioned fiber optic sensor.

[0089] This application provides a battery comprising: a battery pack and the aforementioned fiber optic sensor, wherein the fiber optic sensor is disposed on the inner surface and / or outer surface of the battery pack, and the fiber optic sensor is used to generate reflected light and / or multiple beams, the reflected light and / or multiple beams being used to detect the temperature and strain of the battery pack.

[0090] The battery provided in this application can achieve self-detection of the battery pack by setting up an optical fiber sensor.

[0091] In this embodiment of the application, the battery pack includes at least one battery cell, and the fiber optic sensor includes multiple sub-sensors. The sub-sensors are disposed on the inner surface and / or outer surface of the battery cell, and are used to detect the temperature and / or strain of the corresponding battery cell.

[0092] The sub-sensors in this application correspond to individual battery cells and can accurately detect each individual battery cell in the battery pack, that is, detect specific abnormal battery cells.

[0093] Furthermore, the battery provided in this application can be used in energy storage batteries or power batteries. Specifically, the battery pack can be a pouch battery, a square battery, a blade battery, or a cylindrical battery.

[0094] In this embodiment, the battery pack includes at least one battery group, and the battery group includes at least one battery cell. It is understood that the battery pack includes at least one battery cell. If the battery pack includes multiple battery cells, the multiple battery cells can be connected in parallel and / or in series. The fiber optic sensor includes multiple sub-sensors, which are disposed on the inner and / or outer surfaces of corresponding battery cells. In an optional embodiment, the sub-sensors are disposed on the inner and / or outer surfaces of the battery cell's encapsulation shell. The battery cell and sub-sensors can have a one-to-one correspondence or a one-to-many relationship. Further, multiple fiber optic sensors can be disposed on the inner and / or outer surfaces of the battery pack. If multiple sub-sensors are disposed on the inner and / or outer surfaces of a battery cell, these multiple sub-sensors can originate from the same fiber optic sensor or different fiber optic sensors.

[0095] For example, referring to FIG2, battery A includes a battery pack and a fiber optic sensor X1. The battery pack includes battery cells b1 to b6, and the fiber optic sensor X1 includes sub-sensors a1 to a6. Sub-sensors ai correspond to battery cells bi, that is, sub-sensors ai are disposed on the inner surface and / or outer surface of battery cells bi, and i is 1 to 6.

[0096] For example, referring to FIG3, battery B includes a battery pack and an optical fiber sensor X1. The battery pack includes battery cells c1 to c3. The optical fiber sensor X1 includes sub-sensors a1 to a6. Battery cell c1 corresponds to sub-sensors a1 and a2, battery cell c2 corresponds to sub-sensors a3 and a4, and battery cell c3 corresponds to sub-sensors a5 and a6.

[0097] Furthermore, there are multiple fiber optic sensors, with different fiber optic sensors positioned at different locations within the battery pack.

[0098] For example, referring to Figure 4, battery C includes a battery pack and multiple fiber optic sensors. The battery pack includes battery cells b1 to b6, and the multiple fiber optic sensors are fiber optic sensor X1, fiber optic sensor X2, and fiber optic sensor X3. Fiber optic sensor X1 includes sub-sensors a1 to a6, fiber optic sensor X2 includes sub-sensors d1 to d6, and fiber optic sensor X3 includes sub-sensors e1 to e6. Sub-sensors a1, ei, and di correspond to battery cell bi.

[0099] In Figure 4, multiple fiber optic sensors enable real-time detection of temperature and strain at different locations of different battery cells.

[0100] Multiple fiber optic sensors are disposed at different positions on the inner and / or outer surfaces of the battery pack. For example, fiber optic sensor X1 is disposed in the middle of the battery pack, fiber optic sensor X2 is disposed on one edge of the battery pack, and fiber optic sensor X3 is disposed on the other edge of the battery pack. This application does not limit the arrangement of the multiple fiber optic sensors.

[0101] In one alternative embodiment, the sub-sensor is attached to the inner and / or outer surface of the battery cell. In this embodiment, the fiber optic sensor is fixed to the inner and / or outer surface of the battery pack using adhesive, and the corresponding sub-sensor is also fixed to the inner and / or outer surface of the corresponding battery cell. Specifically, the adhesive can be polyimide tape, PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), epoxy resin (photocurable), or related mixtures.

[0102] This application also provides a battery system including a battery and a detection device, the detection device being connected to a fiber optic sensor on the battery. The detection device is used to determine the temperature and / or strain of a corresponding battery cell based on reflected light and / or multiple beams returned by a sub-sensor based on incident target light.

[0103] In this embodiment of the application, the battery system includes the above-mentioned detection device and battery, which can realize the battery system providing battery functions while self-detecting battery performance.

[0104] Specifically, the detection device includes multiple connection channels, each connected to a fiber optic sensor. The detection device controls different sub-sensors on the fiber optic sensor corresponding to the light source to send target light through the connection channel, and then acquires the reflected light and / or multiple beams returned by the different sub-sensors, thereby determining the temperature and / or strain at the corresponding sub-sensor. This application is able to determine the temperature and strain of each battery cell.

[0105] Referring to Figure 2, a battery system P1 is shown, in which any connection channel of the detection device is connected to the fiber optic sensor when there is only one fiber optic sensor. Referring to Figure 4, a battery system P2 is shown, in which connection channel 1 of the detection device is connected to fiber optic sensor X3, connection channel 2 is connected to fiber optic sensor X1, and connection channel 3 is connected to fiber optic sensor X2.

[0106] Furthermore, the detection device is also used to: determine the lithium plating state of a battery cell based on the strain of the battery cell. Specifically, determining the lithium plating state of a battery cell based on the strain of the battery cell includes: determining the current strain amplitude of the battery cell based on the maximum and minimum strain detected during this battery charging process; acquiring the historical strain amplitude of the battery cell during multiple historical charge-discharge processes; determining the trend of strain amplitude change based on multiple historical strain amplitudes and the current strain amplitude; and determining the lithium plating state based on the inflection point if there is an inflection point in the trend.

[0107] Referring to Figure 5, in the coordinate system of Figure 5, the X-axis represents the number of battery charge-discharge cycles, with one charge plus one discharge constituting one cycle, and the Y-axis represents the strain amplitude. If the current strain amplitude of this charge-discharge cycle is as shown in Figure 5, the strain amplitudes of the multiple charge-discharge cycles prior to this cycle are the historical strain amplitudes. The inflection point indicates that before the inflection point, the historical strain amplitude of the charge-discharge cycle showed an upward trend, and after the inflection point, the strain amplitude of the charge-discharge cycle showed a downward trend.

[0108] Furthermore, the state of the battery cell corresponding to the inflection point is the lithium plating state. The lithium plating state means that the lithium plating thickness of the negative electrode of the battery cell has reached the thickness threshold. Before the lithium plating state, the lithium plating thickness of the battery cell will not affect the use of the battery cell during charging and discharging. After the lithium plating state, the lithium plating thickness of the battery cell will cause the battery performance to drop sharply during charging and discharging, affecting the normal use of the battery.

[0109] Referring to Figure 6, the strain amplitude and SOH (segmented capacity of the battery) change with the number of charge-discharge cycles during the experiment. It can be seen that after the inflection point of the strain amplitude, SOH drops sharply. The sharp drop in SOH will affect the normal use of the battery cell. SOH is calculated as follows: obtain the charge Q of the battery cell when it is first fully charged, obtain the charge q of the battery cell when it is fully charged, and SOH = q / Q. Furthermore, referring to Figure 7, microscopic images (a) of the negative electrode before the inflection point and (b) of the negative electrode after the inflection point are shown. In microscopic image (a), it can be seen that the active material on the electrode surface remains intact without defects, and the thickness of the negative electrode is about 60 μm. In microscopic image (b), a large area of ​​coating layer is found in the morphology of the battery electrode layer, forming a relatively thick lithium plating layer. The capacity decreases sharply, and the thickness reaches about 80 μm. A clear lithium plating layer with a thickness of about 10 μm can be seen. After the inflection point, it can be clearly deduced that there is lithium plating behavior at the battery electrode layer, resulting in a large area of ​​irreversible dead lithium. The strain increases first, the capacity decreases, and the strain amplitude drops sharply. Irreversible lithium is deposited on the surface of the negative electrode. The formation of a large number of dead lithium on the surface of the negative electrode will form lithium dendrites, which will seriously affect the safety behavior of the battery.

[0110] It is understood that by detecting the lithium plating state, this application can determine the current performance state of the battery.

[0111] In this embodiment of the application, the detection device is further configured to: determine the state of the battery cell based on the temperature and / or strain of the battery cell; and output early warning information when the state of the battery cell is abnormal.

[0112] Specifically, determining the state of a battery cell based on its temperature and / or strain includes: if the strain is greater than a strain threshold and / or the temperature is greater than a temperature threshold, determining that the state of the battery cell corresponding to the sub-sensor is abnormal.

[0113] It is understandable that if the strain exceeds the strain threshold, the battery cell will bulge or show signs of impending failure. If the temperature exceeds the temperature threshold, the battery cell will be in an overheated state.

[0114] In this embodiment, the temperature and strain of each battery cell can be monitored in real time. If the temperature exceeds a temperature threshold, it can be determined that the battery is in an abnormal state, and an overheating warning will be issued. Similarly, if the strain exceeds a strain threshold, it can also be determined that the battery is in an abnormal state, and an excessive strain warning will be issued.

[0115] Furthermore, the system can output the temperature and strain changes of each individual battery cell over time, thereby enabling monitoring of the battery cell's temperature and strain. Each battery cell also has a corresponding location within the battery pack, allowing for accurate location of the individual battery cell in case of an anomaly.

[0116] Referring to Figure 8, the strain of a single battery cell changes over time. During the charging and discharging process of the battery cell before 40,000 s, the strain change indicates that the battery cell undergoes reversible volume expansion. After 40,000 s, the strain change indicates that the battery cell begins to undergo irreversible volume expansion.

[0117] Specifically, in Figure 8, as the number of battery cycles increases and irreversible lithium deposition occurs on the negative electrode, the strain begins to expand and increase rapidly. When lithium dendrites form, the amplitude of the strain curve gradually converges. The appearance of the inflection point in the strain amplitude indicates the presence of lithium plating.

[0118] It is evident that prolonged battery use (aging) and lithium plating lead to irreversible volume expansion, resulting in increased irreversible strain on the battery surface. This increased strain amplitude leads to thicker lithium plating, increased irreversible lithium content, and decreased battery capacity. Simultaneously, the increased strain on the battery surface and the resulting increase in irreversible lithium on the negative electrode cause a rapid decrease in the strain amplitude on the battery surface. This application allows for real-time online detection of battery strain, thereby determining the lithium plating state of the battery.

[0119] In this embodiment, the detection device is connected to a display, which displays the changes in temperature and strain over time in real time, allowing the user to view the battery's temperature and strain in real time.

[0120] Furthermore, the testing device is a Battery Management System (BMS).

[0121] This application utilizes a single fiber optic sensor externally placed on the battery surface to detect whether the battery is in a lithium-plating state, achieving non-destructive lithium plating detection. A detection device connected to a sub-sensor is used to monitor temperature and strain parameters in real time. The single fiber optic sensor is attached to the battery's outer surface, reducing the need for structural modifications to the battery, minimizing interference from external factors, lowering battery costs, and simplifying the structure. Furthermore, this application uses a fiber optic sensor to detect temperature and strain, distinguishing the lithium plating state of the battery through the inflection point of strain amplitude. The method is simple, low-cost, and facilitates system testing of the entire vehicle's power battery.

[0122] Furthermore, the fiber optic sensor employs etching to obtain the required spacing between gratings. Under the influence of temperature and stress, the fiber optic sensor effectively alters the wavelength of reflected light. When the target light passes through the grating, the wavelengths reflected by the grating vary due to temperature and stress, allowing for clear identification of the corresponding wavelength change characteristics using a demodulator. This application uses a fiber optic sensor to perform non-destructive testing on the inner and / or outer surfaces of the battery. When an inflection point appears in the strain amplitude, a lithium plating state can be determined. In addition, the detection device can be integrated with the BMS or connected to a display system to display the obtained temperature and strain. After data processing, the location and time point of the lithium plating state are obtained, enabling real-time online monitoring of the battery. This allows for both fundamental scientific research and early warning of anomalies in the vehicle battery and / or battery system. The detection device of this application can solve the challenge of assessing the battery health status during charging and discharging under high-power and wide-temperature conditions.

[0123] Furthermore, this application also provides a detection system, including the aforementioned fiber optic sensor and detection device, wherein the detection device is connected to the fiber optic sensor. The detection system of this application can detect the temperature and / or strain of any object. Specific details are given in the above embodiments and will not be repeated here.

[0124] In addition, this application also provides a detection method applied to the above-mentioned detection device. The detection method includes: determining the temperature and / or strain of the corresponding target object based on the reflected light and / or multiple beams returned by the sub-sensor based on the incident target light.

[0125] The specific implementation process of the detection method provided in this application is the same as that in the above embodiments, and will not be repeated here.

[0126] Furthermore, this application also provides a vehicle including the aforementioned battery system.

[0127] The battery system installed in the vehicle enables early warning analysis of the entire vehicle battery, as well as vehicle battery detection and battery status assessment, thereby achieving the early warning function of the safety system. The vehicle provided in this application can implement the above-mentioned battery system embodiments, which will not be elaborated further here.

[0128] Furthermore, in some of the processes described in the above embodiments and accompanying drawings, multiple operations appear in a specific order. However, it should be clearly understood that these operations may not be executed in the order they appear herein, or may be executed in parallel. The sequence numbers are merely used to distinguish different operations, and the sequence numbers themselves do not represent any execution order. Additionally, these processes may include more or fewer operations, and these operations may be executed sequentially or in parallel. It should be noted that the descriptions such as "second" and "first" in this document are used to distinguish different messages, devices, modules, etc., and do not represent a sequential order, nor do they limit "second" and "first" to different types.

[0129] Figure 9 is a schematic diagram of the structure of an electronic device provided in an example embodiment of this application. As shown in Figure 9, the electronic device 90 includes: a processor 91, and a memory 92 communicatively connected to the processor 91, the memory 92 storing computer-executed instructions.

[0130] The processor executes computer execution instructions stored in the memory to implement the detection method provided in any of the above method embodiments. The specific functions and technical effects to be achieved will not be elaborated here.

[0131] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the detection method provided in any of the above method embodiments.

[0132] This application also provides a computer program product, which includes a computer program stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the electronic device to perform the detection method provided in any of the above method embodiments.

[0133] In the embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.

[0134] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0135] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0136] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0137] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is merely an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the system can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0138] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0139] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An optical fiber sensor, characterized by, The application relates to a fiber sensor and a detection device. The fiber sensor comprises a fiber and a plurality of sub-sensors arranged in sequence along a fiber extension direction of the fiber. The sub-sensors are used for detecting temperature and / or strain at corresponding positions.

2. The fiber optic sensor of claim 1, wherein, The sub-sensors receive target light rays in corresponding wavelength ranges, and different sub-sensors receive target light rays in different wavelength ranges.

3. The fiber optic sensor of claim 1, wherein, The sub-sensors comprise fiber grating sensor units and Fabry-Perot cavity sensor units, and the Fabry-Perot cavity sensor units are located on a light path of transmitted light of the fiber grating sensor units.

4. The fiber optic sensor of any one of claims 1 to 3, wherein, The fiber further comprises a cladding covering the core.

5. A detection device, characterized in that The detection device is connected to the fiber sensor of any one of claims 1 to 4, and the detection device is used for determining temperature and / or strain of a target object detected by a sub-sensor according to reflected light and / or a plurality of light beams returned by the sub-sensor based on incident target light rays.

6. The detection device of claim 5, wherein, The determination of temperature and / or strain of the target object detected by the sub-sensor according to the reflected light and / or the plurality of light beams returned by the sub-sensor based on the incident target light rays comprises: demodulating the plurality of light beams returned by the sub-sensor based on the incident target light rays to obtain a phase difference between adjacent light beams in the plurality of light beams; and determining the strain according to the phase difference.

7. The detection device of claim 5, wherein, The determination of temperature and / or strain of the target object detected by the sub-sensor according to the reflected light and / or the plurality of light beams returned by the sub-sensor based on the incident target light rays comprises: demodulating the reflected light and the plurality of light beams returned by the sub-sensor based on the incident target light rays to obtain a wavelength of the reflected light and a phase difference between adjacent light beams in the plurality of light beams; and determining the temperature according to the phase difference, the wavelength of the reflected light and a wavelength of the target light rays.

8. The detection device according to any one of claims 5 to 7, characterized in that The detection device is further used for: determining a maximum temperature detected by a plurality of sub-sensors as temperature of the target object; and / or determining a maximum strain detected by the plurality of sub-sensors as strain of the target object.

9. A battery, characterized by The application also relates to a battery pack. The battery pack comprises at least one battery cell, and the fiber sensor comprises a plurality of sub-sensors arranged on inner and / or outer surfaces of the battery cell.

10. The battery of claim 9, wherein, The sub-sensors are pasted on the inner and / or outer surfaces of the battery cell.

11. The battery of claim 10, wherein, A plurality of fiber sensors are arranged at different positions of the battery pack.

12. The battery of any one of claims 9 to 11, wherein, The application also relates to a detection device and a battery.

13. A battery system characterized by, The detection device is connected to the fiber sensor on the battery, and the detection device is used for determining temperature and / or strain of a corresponding battery cell according to reflected light and / or a plurality of light beams returned by a sub-sensor based on incident target light rays. The detection device is further used for:

14. The battery system of claim 13, wherein, determining a lithium precipitation state of the battery cell according to the strain of the battery cell. ​ 15. The battery system of claim 14, wherein, The determining the lithium precipitation state of the battery cell according to the strain of the battery cell comprises: determining a current strain amplitude of the battery cell based on the maximum strain and the minimum strain of the battery cell detected in the current battery charging process; obtaining historical strain amplitudes of the battery cell in historical charging and discharging processes; determining a change trend of the strain amplitude according to the historical strain amplitudes and the current strain amplitude; if there is an inflection point in the change trend, determining the lithium precipitation state according to the inflection point.

16. The battery system of any one of claims 13-15, wherein, The detection device is further used for: determining a state of the battery cell based on the temperature and / or strain of the battery cell; outputting a warning information in a case that the state of the battery cell is an abnormal state.

17. The battery system of claim 16, wherein, The determining the state of the battery cell based on the temperature and / or strain of the battery cell comprises: if the strain is greater than a strain threshold value and / or the temperature is greater than a temperature threshold value, determining that the state of the battery cell corresponding to the sub-sensor is the abnormal state.

18. The battery system of any one of claims 13-15, wherein, The detection device is a battery management system.

19. A detection system characterized by, The detection device according to any one of claims 5 to 8 is connected with the optical fiber sensor according to any one of claims 1 to 4.

20. A method of detection, comprising: The detection method applied to the detection device according to any one of claims 5 to 8 comprises: determining the temperature and / or strain of the target object according to the reflected light and / or the plurality of light beams returned by the sub-sensor based on the incident target light.

21. A vehicle characterized by The vehicle comprises the battery system according to any one of claims 13 to 18.

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