Power battery deformation monitoring system and power battery

Abstract

The present disclosure provides a deformation monitoring system of a power battery and a power battery, and belongs to the technical field of new energy vehicles. The power battery comprises a box body and an internal component connected in the box body; the deformation monitoring system comprises at least one detection circuit and a light source demodulator, each detection circuit comprises a plurality of optical fiber sensors and an optical fiber, the optical fiber sequentially connects the plurality of optical fiber sensors, the plurality of optical fiber sensors are arranged at intervals and embedded in the internal component; the light source demodulator is connected with the internal component, and the light source demodulator is connected with two ends of each detection circuit. The present disclosure can monitor the strain of the power battery, so as to determine whether the power battery deforms in real time.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of new energy vehicles, and particularly relates to a deformation monitoring system of a power battery and the power battery. BACKGROUND

[0002] The strain of the power battery refers to the deformation of the overall structure of the box body of the power battery after the box body is subjected to various forms of damage such as mechanical vibration, mechanical impact, collision or extrusion during use. The deformation of the box body is conducted to the internal components through the bottom structure of the box body, and then the internal structure of the power battery is changed. In addition, the internal component structure may be deformed or misaligned due to the self-heating expansion of the battery cell or the external extrusion during use. The deformation or misalignment of the internal component structure may cause poor contact between the battery cell and the copper bar, and in severe cases, may even cause problems in the vehicle circuit.

[0003] In related technologies, in order to monitor the deformation of the internal components, the side wall of the box body is generally polished, and then the corresponding sensor (such as a strain gauge) is arranged in the internal components in the box body to monitor the deformation of the internal components. Or after the power battery is damaged, the internal components are directly disassembled, and then a measuring instrument is used to monitor the deformation of the internal components. When disassembling the internal components, some parts outside the internal components are also damaged.

[0004] However, in the above manner, when monitoring the internal components by pasting the strain gauge, since the strain gauge is a metal structure, it will undoubtedly be affected by the high-voltage electromagnetic interference inside the internal components, thereby affecting the monitoring accuracy. When measuring the deformation of the internal components by disassembling the internal components, since the foam needs to be damaged, this will increase the waste and the manufacturing cost of the internal components. SUMMARY

[0005] The present disclosure provides a deformation monitoring system of a power battery and the power battery, which can monitor the strain of the power battery in real time without damaging the original structure of the power battery, so as to quickly determine whether the power battery is deformed. The technical solution is as follows:

[0006] The deformation monitoring system of the power battery provided by the embodiments of the present disclosure comprises at least one detection line and a light source demodulator, each detection line comprises a plurality of optical fiber sensors and an optical fiber, the optical fiber sequentially connects the plurality of optical fiber sensors, the plurality of optical fiber sensors are arranged at intervals and are pasted or embedded on the surface of the internal component structure, the light source demodulator is located in the box and connected with the internal component, and the light source demodulator is connected with both ends of each detection line.

[0007] In another implementation manner of the present disclosure, the internal component comprises a plurality of battery cells, a heat-conducting structural adhesive, a liquid cooling plate and a reinforcing frame, the battery cells, the heat-conducting structural adhesive and the liquid cooling plate are sequentially connected along the direction from the top to the bottom of the box, the reinforcing frame comprises a frame body, at least one cross beam and a longitudinal beam, the reinforcing frame is located in the box and on the side of the liquid cooling plate facing the battery cells, the cross beam and the longitudinal beam are connected with the inner wall of the box, the at least one cross beam and the longitudinal beam are located in the frame body, the at least one cross beam is connected with the frame body, the at least one cross beam and the longitudinal beam are cross-connected and define a plurality of cavities together with the frame body and the liquid cooling plate, the plurality of battery cells correspond to the plurality of cavities one by one, and the battery cells are connected in the corresponding cavities through the heat-conducting structural adhesive, the light source demodulator is connected on the cross beam or the longitudinal beam, and the at least one detection line comprises at least one of a first detection line and a second detection line, the plurality of optical fiber sensors in the first detection line are all first optical fiber sensors, the plurality of first optical fiber sensors are connected with the liquid cooling plate, and the plurality of optical fiber sensors in the second detection line are all second optical fiber sensors, and the plurality of second optical fiber sensors are connected with the reinforcing frame.

[0008] In another implementation manner of the present disclosure, the plurality of first optical fiber sensors in the first detection line are connected on the upper surface of the liquid cooling plate facing the battery cells at intervals, the middle part of the optical fiber in the first detection line is encapsulated in the heat-conducting structural adhesive, and the two ends of the optical fiber in the first detection line are located outside the heat-conducting structural adhesive.

[0009] In another implementation manner of the present disclosure, the lower surface of the liquid cooling plate facing the bottom plate has a cooling groove for the flow of cooling liquid, the plurality of first optical fiber sensors in the first detection line are connected in the cooling groove at intervals, and the optical fiber in the first detection line is arranged along the cooling groove.

[0010] In another implementation manner of the present disclosure, the plurality of second optical fiber sensors in the second detection line are arranged at intervals along the circumference of the inner wall of the frame body, and the plurality of second optical fiber sensors are all connected with the inner wall of the frame body.

[0011] In a further implementation form of the disclosure, the second detection lines are arranged one-to-one corresponding to the cavities, and for any one of the second detection lines, a plurality of second fiber sensors in the second detection line are arranged along a circumference of the corresponding cavity, and the plurality of second fiber sensors are connected with at least one of the inner wall of the frame body, the cross beam or the longitudinal beam.

[0012] In a further implementation form of the disclosure, the monitoring system further comprises a splitter and a combiner, the splitter and the combiner are both located at the center of the reinforcing frame and are both connected with the intersection of the cross beam and the longitudinal beam; the splitter has a plurality of output ends, the combiner has a plurality of input ends, the plurality of output ends of the splitter are arranged one-to-one corresponding to the plurality of input ends of the combiner; a second detection line is connected between each output end of the splitter and the corresponding input end of the combiner, the input end of the splitter is connected with the output end of the light source demodulator, and the output end of the combiner is connected with the input end of the light source demodulator.

[0013] In a further implementation form of the disclosure, the plurality of second fiber sensors are arranged along the circumference of the frame body, and the plurality of second fiber sensors and the fiber are both connected with the outer wall of the frame body.

[0014] In a further implementation form of the disclosure, the reinforcing frame further comprises a plurality of lugs, the plurality of lugs are arranged along the circumference of the frame body and are connected with the outer wall of the frame body; the second fiber sensor is located in a weld joint formed between one of the lugs and the outer wall of the frame body and is bonded with the weld joint.

[0015] In a further implementation form of the disclosure, a power battery is also provided, the power battery comprises a deformation monitoring system, a box body and an internal component, the internal component is located in the box body, the deformation monitoring system is connected with the internal component, and the monitoring system is the deformation monitoring system described above.

[0016] The technical scheme provided by the embodiments of the disclosure has the following beneficial effects:

[0017] When the deformation monitoring system provided by the embodiments of the disclosure is used to monitor the power battery, since the monitoring system comprises at least one detection line and a light source demodulator, and each detection line comprises a plurality of fiber sensors and a fiber, the fiber sequentially connects the plurality of fiber sensors, and the plurality of fiber sensors are arranged at intervals and are embedded in the internal component, so that the plurality of different positions in the internal component can be monitored by the plurality of fiber sensors, and thus the deformation amounts corresponding to the different positions of the internal component can be obtained according to the monitoring results of the plurality of fiber sensors.

[0018] And, since the deformation monitoring system further comprises a light source demodulator, and the light source demodulator is connected with the internal component, the light source demodulator is connected with the two ends of the optical fiber respectively, so that the multiple optical fiber sensors in each detection line can be connected together through the optical fiber, so that the light signal emitted by the light source demodulator can enter the optical fiber sensor. When the light source demodulator emits light signal, the light signal can be transmitted in each optical fiber sensor in each detection line through the optical fiber. When the light signal emitted by the light source demodulator passes through each optical fiber sensor, a reflected light signal can be correspondingly reflected back, and the reflected light signal reflected back is transmitted in the light source demodulator again through the optical fiber. The light source demodulator can demodulate the strain value of the multiple detection positions corresponding to the internal component according to the information of the center wavelength of the reflected light signal reflected back by each optical fiber sensor.

[0019] Therefore, once the bottom of the vehicle body is subjected to the load action of impact, scratching and the like, the deformation after the internal component is damaged can be quickly learned through the above monitoring system, so as to estimate the position and size of the deformation existing in the internal component, without disassembling the internal component and without pasting strain gauges, thereby reducing the damage to the original structure of the internal component. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A structural schematic diagram of a power battery provided by the embodiments of the present disclosure is shown in the figure.

[0022] Figure 2 A schematic diagram of the arrangement mode of the first deformation monitoring system provided by the embodiments of the present disclosure is shown in the figure.

[0023] Figure 3 A schematic diagram of the arrangement mode of the second deformation monitoring system provided by the embodiments of the present disclosure is shown in the figure.

[0024] Figure 4 A schematic diagram of the arrangement mode of the third deformation monitoring system provided by the embodiments of the present disclosure is shown in the figure.

[0025] Figure 5 A schematic diagram of the arrangement mode of the fourth deformation monitoring system provided by the embodiments of the present disclosure is shown in the figure.

[0026] Figure 6A fifth arrangement of a deformation monitoring system is provided by the embodiments of the present disclosure.

[0027] The meanings of the symbols in the figures are as follows:

[0028] 100, box body;

[0029] 200, internal assembly; 201, battery cell; 202, heat-conducting structural adhesive; 203, liquid cooling plate; 2031, cooling groove; 204, bottom guard plate; 205, foam; 206, reinforcing frame; 2061, frame body; 2062, cross beam; 2063, longitudinal beam; 2064, lifting lug;

[0030] 1, fiber sensor; 11, first fiber sensor; 12, second fiber sensor; 2, optical fiber; 3, light source demodulator; 4, optical fiber coupler; 5, splitter; 6, combiner. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the embodiments of the present disclosure will be described in further detail below with reference to the drawings.

[0032] In order to clearly illustrate the deformation monitoring system of the power battery provided by the embodiments of the present disclosure, the detection principle of the fiber grating sensor will be briefly described first.

[0033] The fiber grating sensor is a kind of fiber sensing technology based on reflected light wavelength information, and its sensing unit is a fiber grating. The physical quantity tested by the fiber grating sensor depends not only on the demodulator, but also on the fiber grating.

[0034] In detection, the fiber grating is connected with the demodulator through an optical fiber. When the broadband light emitted by the demodulator passes through the fiber grating, the fiber grating will reflect back a narrowband light of a certain center wavelength (the wavelength of the narrowband light depends on the grating pitch of the fiber grating. Its mathematical expression is: λ=2nΛ, where λ is the center wavelength of the narrowband light reflected back by the fiber grating; n is the effective refractive index of the fiber core; Λ is the grating pitch. When the strain change monitored by the fiber grating changes, the grating pitch will change, that is, the center wavelength of the reflected narrowband light (i.e. the reflection center wavelength) will shift relative to the original center wavelength (i.e. the center wavelength of the narrowband light reflected back by the fiber grating when it is not subjected to strain), that is, the wavelength drift. According to the wavelength drift of the center wavelength of the reflected narrowband light, the strain value of the measured object can be determined.

[0035] Among them, the demodulator can be integrated with a light source, an optical detection module, a signal demodulation module, a data processing module and the like.

[0036] In this embodiment, the demodulator can be directly connected with the battery management system (BMS) of the vehicle, the demodulator reads the wavelength drift of the fiber bragg grating and outputs an electrical signal, and the BMS receives the electrical signal, analyzes and calculates, and outputs a safety signal related to the battery strain to the vehicle.

[0037] The basic structure of the power battery is briefly described below.

[0038] Figure 1 The structure diagram of the power battery provided by the embodiment of the present disclosure is combined with Figure 1 The power battery includes a box body 100 and an internal assembly 200 connected in the box body 100. The internal assembly 200 includes a plurality of battery cells 201, a heat-conducting structural adhesive 202, a liquid cooling plate 203, and a reinforcing frame 206. The battery cells 201, the heat-conducting structural adhesive 202, and the liquid cooling plate 203 are sequentially connected along the direction from the top to the bottom of the box body 100.

[0039] The reinforcing frame 206 includes a frame body 2061, a plurality of cross beams 2062, and longitudinal beams 2063. The reinforcing frame 206 is located in the box body 100 and on the side of the liquid cooling plate 203 facing the battery cells 201. The frame body 2061 is connected with the inner wall of the box body 100. At least one cross beam 2062 is parallel to each other and connected with the frame body 2061. The longitudinal beams 2063 are located in the frame body 2061 and cross-connect with at least one cross beam 2062. The plurality of cross beams 2062, the longitudinal beams 2063, the frame body 2061, and the liquid cooling plate 203 define a plurality of cavities. The plurality of battery cells 201 correspond to the plurality of cavities one by one. The battery cells 201 are connected with the liquid cooling plate 203 in the corresponding cavities through the heat-conducting structural adhesive 202.

[0040] Since the battery cells 201 generate a large amount of heat during work, if not cooled in time, it may cause the battery cells 201 to catch fire and other risks. The heat-conducting structural adhesive 202 as a heat-conducting medium can efficiently transfer the heat inside the battery cells 201, so that the battery cells 201 can stably operate, thereby enhancing the stability of the battery cells 201 and prolonging the service life thereof.

[0041] In addition, since the heat-conducting structural adhesive 202 is a material with high strength, high temperature resistance, and strong heat conduction performance, the heat-conducting structural adhesive 202 can effectively protect the battery cells 201. Moreover, by virtue of the characteristics of the heat-conducting structural adhesive 202 that can withstand high temperature and reduce temperature difference, the heat-conducting structural adhesive 202 can protect the battery cells 201 from thermal runaway, and enhance the stability and reliability of the internal assembly 200.

[0042] The liquid cooling plate 203 further dissipates heat from the battery cell 201, enabling it to cool down rapidly and thus improving its stability. The bottom protective plate 204 serves as the bottom structure of the internal component 200, protecting it. Foam 205 is sandwiched between the bottom protective plate 204 and the bottom of the housing 100 for vibration damping and cushioning, further protecting the internal component 200. The reinforcing frame 206 is used to mount the battery cell 201, limiting and fixing its position.

[0043] In addition, to enhance the cooling effect, the liquid cooling plate 203 includes an upper and lower heat spreader plate and a flow channel plate that are attached together. The heat spreader plate is a stamped aluminum sheet. The flow channel plate is a metal sheet with liquid flow channels.

[0044] This disclosure provides a deformation monitoring system for a power battery, such as... Figure 2 As shown, the deformation monitoring system includes at least one detection line and a light source demodulator 3. Each detection line includes multiple fiber optic sensors 1 and fiber optics 2. The fiber optics 2 connect the multiple fiber optic sensors 1 in series. The multiple fiber optic sensors 1 are arranged at intervals and are all located inside the housing 100 and connected to the internal components 200. The light source demodulator 3 is located inside the housing 100 and connected to the internal components 200. The light source demodulator 3 is connected to both ends of each detection line.

[0045] When monitoring a power battery using the monitoring system provided in this embodiment, the deformation monitoring system includes at least one detection line and a light source demodulator 3. Each detection line includes multiple fiber optic sensors 1 and fiber optics 2. The fiber optics 2 connect the multiple fiber optic sensors 1 in series. The multiple fiber optic sensors 1 are arranged at intervals and are all connected to the internal component 200. In this way, multiple different positions of the internal component 200 can be monitored by multiple fiber optic sensors 1, and the deformation of the internal component 200 corresponding to different positions can be obtained based on the monitoring results of multiple fiber optic sensors 1.

[0046] Furthermore, since the deformation monitoring system also includes a light source demodulator 3, which is connected to the internal component 200 and connected to both ends of the optical fiber 2, multiple fiber optic sensors 1 in each detection line can be connected to the light source demodulator 3 via the optical fiber 2. This allows the optical signal emitted by the light source demodulator 3 to enter the fiber optic sensor 1. When the optical signal emitted by the light source demodulator 3 passes through each fiber optic sensor 1, each fiber optic sensor 1 will reflect back a corresponding reflected optical signal. The reflected optical signal is then transmitted back to the light source demodulator 3 via the optical fiber 2. Based on the center wavelength of the reflected optical signal from each fiber optic sensor 1, the light source demodulator 3 can demodulate the strain values ​​at multiple detection positions of the internal component 200.

[0047] Therefore, once the bottom of the vehicle body is subjected to the load of impact, scratch, etc., the deformation of the internal assembly 200 after the damage can be quickly learned through the above monitoring system, so as to estimate the position and size of the deformation of the internal assembly 200, without disassembling the internal assembly 200 or embedding the sensor through drilling, thereby reducing the damage to the original structure of the internal assembly 200.

[0048] Meanwhile, the above monitoring system is arranged in the internal assembly 200 without occupying additional space, so that the overall structure of the box body 100 does not change greatly, and thus can be adapted to most internal assemblies 200 on the market.

[0049] In a possible implementation, continuing to refer to Figure 2 , the at least one detection line includes a first detection line, and the plurality of optical fiber sensors 1 in the first detection line are all first optical fiber sensors 11, and the plurality of first optical fiber sensors 11 are connected with the liquid cooling plate 203.

[0050] That is, the plurality of first optical fiber sensors 11 are arranged on the liquid cooling plate 203, so that the internal assembly 200 can also be monitored by the plurality of first optical fiber sensors 11.

[0051] Continuing to refer to Figure 2 , the plurality of first optical fiber sensors 11 can be arranged on the upper surface of the liquid cooling plate 203. Alternatively, the plurality of first optical fiber sensors 11 in the first detection line are connected on the upper surface of the liquid cooling plate 203 facing the battery cell 201 at intervals, the middle part of the optical fiber 2 in the first detection line is encapsulated in the heat-conducting structural adhesive 202, and the two ends of the optical fiber 2 in the first detection line are located outside the heat-conducting structural adhesive 202.

[0052] In the above implementation, the plurality of first optical fiber sensors 11 in the first detection line are connected on the upper surface of the liquid cooling plate 203 facing the heat-conducting structural adhesive 202 at intervals, so that the first optical fiber sensors 11 can be arranged in different interlayers in the internal assembly 200, so that the existence of the plurality of first optical fiber sensors 11 has little effect on the adhesion between the adjacent two interlayers, thereby not significantly increasing the height of the box body 100, and ensuring that the box body 100 can still meet the overall requirements in the height direction. Moreover, the optical fiber 2 in the first detection line is encapsulated in the heat-conducting structural adhesive 202, so that the optical fiber 2 in the first detection line can be fixed directly by the bonding of the heat-conducting structural adhesive 202, thereby saving the budget for fixing the optical fiber 2 in the first detection line, facilitating the fixing of the optical fiber 2 in the first detection line, and saving costs.

[0053] In combination with Figure 2When the optical fiber 2 in the first detection line is encapsulated by the heat-conducting structural adhesive 202, the end of the optical fiber 2 extends out of the heat-conducting structural adhesive 202, and the other parts of the optical fiber 2 in the first detection line are encapsulated in the heat-conducting structural adhesive 202.

[0054] Exemplarily, the plurality of first optical fiber sensors 11 can be connected on the upper surface of the liquid cooling plate 203 by means of strain glue or welding, so as to facilitate the fixation of the first optical fiber sensors 1.

[0055] In addition, when the first detection line is arranged on the upper surface of the liquid cooling plate 203 in the above manner, the following steps can be performed: the arrangement points of the first optical fiber sensors 11 to be arranged are uniformly marked on the upper surface of the liquid cooling plate 203 in advance. Then, the first optical fiber sensors 11 are adhered to the arrangement points by means of strain glue. Next, the optical fiber 2 in the first detection line is wound on the upper surface of the liquid cooling plate 203, and the first optical fiber sensors 11 are connected in series, and two ends of the optical fiber 2 in the first detection line are led out. Next, the heat-conducting structural adhesive 202 is arranged in each cavity and laid on the upper surface of the liquid cooling plate 203, and then the battery cell 201 is arranged in each cavity and adhered to the corresponding heat-conducting structural adhesive 202. After that, the light source demodulator 3 is arranged on the cross beam 2062 or the longitudinal beam 2063. The two ends of the optical fiber 2 in the first detection line encapsulated in the heat-conducting structural adhesive 202 are connected to the light source demodulator 3, and the arrangement of the first detection line in the above manner is completed.

[0056] Exemplarily, the same number of first optical fiber sensors 11 can be arranged in the region of the corresponding liquid cooling plate 203 in each cavity, for example, four first optical fiber sensors 11 are arranged respectively. Moreover, the four first optical fiber sensors 11 can be arranged in a rectangular shape on the liquid cooling plate 203 when arranged.

[0057] Figure 3 The second deformation monitoring system arrangement manner provided by the embodiment of the present disclosure is schematically shown in the figure, which is combined with Figure 3 Optionally, in addition to the above-mentioned arrangement manner of the first detection line, the first detection line can also be connected on the lower surface of the liquid cooling plate 203 facing the bottom guard plate 204.

[0058] Optionally, the lower surface of the liquid cooling plate 203 facing the bottom guard plate 204 has a cooling groove 2031 for the flow of cooling liquid. The plurality of first optical fiber sensors 11 in the first detection line are connected in the cooling groove 2031 at intervals. The optical fiber 2 in the first detection line is arranged along the cooling groove 2031.

[0059] In the above implementation, the plurality of first optical fiber sensors 11 in the first detection line and the corresponding optical fibers 2 are arranged in the cooling groove 2031, so that the special structural features of the cooling groove 2031 of the liquid cooling plate 203 can be fully utilized, and the first optical fiber sensors 11 can be uniformly arranged on the lower surface of the liquid cooling plate 203 without planning the layout of the first detection line in advance, thereby accelerating the development cycle of the monitoring system.

[0060] Optionally, the cooling groove 2031 is laid in a serpentine shape on the lower surface of the liquid cooling plate 203. The cooling groove 2031 has an inlet end and an outlet end, which are in communication with each other and are located at a corner position of the liquid cooling plate 203.

[0061] The monitoring system further comprises an optical fiber coupler 4, which is located in the box 100 and is embedded in the side wall of the reinforcing frame 2061 (see Figure 6 ). The optical fibers 2 in the cooling groove 2031 are connected to the optical source demodulator 3 through the optical fiber coupler 4.

[0062] In the above implementation, the cooling groove 2031 is configured in the above structure, so that the two ends of the optical fiber 2 are located at the same position of the cooling groove 2031, and the two ends of the optical fiber 2 in the first detection line can be more conveniently and quickly connected to the optical fiber coupler 4 on the reinforcing frame 206.

[0063] The arrangement of the optical fiber coupler 4 can lead the first detection line in the cooling groove 2031 from outside the frame 2061 back to the optical source demodulator 3 in the frame 2061, without affecting the air tightness of the battery cell 201, that is, the overall air tightness between the optical fiber 2 and the battery cell 201 can be improved through the arrangement of the optical fiber coupler 4.

[0064] In this example, the optical fiber coupler 4 is embedded in the side wall of the reinforcing frame 206 in the form of a plug. The so-called embedding is that a connecting hole is provided in the side wall of the reinforcing frame 206, and the optical fiber coupler 4 is plugged into the connecting hole, and the optical fiber coupler 4 is in sealing connection with the side wall of the reinforcing frame 206.

[0065] It should be noted that, Figure 3 in order to clearly show the arrangement position of the plurality of first optical fiber sensors 11 in the first detection line and the corresponding optical fibers 2, the optical fiber coupler 4 is shown. The optical fiber coupler 4 is actually connected in the manner of Figure 6 .

[0066] Exemplarily, when the first detection line is arranged in the cooling groove 2031, the following steps can be performed: evenly divide the arrangement points of the first optical fiber sensor 11 in the cooling groove 2031 of the lower surface of the liquid cooling plate 203, and then mark. Then evenly coil the optical fiber 2 in the first detection line in the cooling groove 2031 of the liquid cooling plate 203, and fix the first optical fiber sensor 11 at the marked position by using strain glue or welding. Then connect the two ends of the optical fiber 2 in the first detection line into the optical fiber coupler 4, and lead out the two ends of the optical fiber 2 from the optical fiber coupler 4 (one end as light source output, and the other end as demodulation input), and connect into the light source demodulator 3 on the cross beam 2062 or the longitudinal beam 2063, so as to complete the arrangement of the first detection line.

[0067] Exemplarily, when the optical fiber 2 in the first detection line is arranged in the cooling groove 2031, the bending radius of the corresponding formed bending area is generally 20 times the outer diameter of the optical fiber, that is, the bending radius of the optical fiber is 2.5-2.8 mm. The macro-bending loss of the optical fiber 2 is ≤0.1 dB. In this way, the bending of the optical fiber 2 in the tortuous cooling groove 2031 along the lower surface of the liquid cooling plate 203 will not affect the detection accuracy.

[0068] Figure 4 The third arrangement mode of the deformation monitoring system provided by the embodiment of the present disclosure is shown in the figure, which is combined with Figure 4 In this embodiment, at least one detection line is a second detection line. The plurality of optical fiber sensors in the second detection line are second optical fiber sensors 12, and the plurality of second optical fiber sensors 12 are connected with the reinforcing frame 206.

[0069] In the above implementation manner, by arranging the plurality of optical fiber sensors 1 on the reinforcing frame 206 or the liquid cooling plate 203, the deformation of different positions inside the internal assembly 200 can be monitored by the optical fiber sensors 1, and the monitoring of the deformation inside the internal assembly 200 is realized. Moreover, the light source demodulator 3 is connected to the cross beam 2062 or the longitudinal beam 2063, so that the connection between the light source demodulator 3 and the internal assembly 200 is facilitated, and meanwhile, the arrangement of the light source demodulator 3 inside the internal assembly 200 does not affect the overall structure of the internal assembly 200.

[0070] Referring to Figure 4 The second detection line can be arranged in the following manner:

[0071] Optionally, the plurality of second optical fiber sensors 12 in the second detection line are arranged along the circumference of the inner wall of the frame body 2061, and the plurality of second optical fiber sensors 12 are connected with the inner wall of the frame body 2061.

[0072] In the above implementation, the second optical fiber sensor 12 in the second detection line and the corresponding optical fiber 2 are arranged on the inner wall of the reinforcing frame 206, and the deformation of multiple positions of the internal assembly 200 can also be monitored. That is, after the internal assembly 200 is deformed, the frame 2061 as the peripheral structure of the battery cell 201 will inevitably be deformed, and at this time, the second optical fiber sensor 12 arranged on the inner wall of the frame 2061 can directly monitor different positions.

[0073] In the above arrangement of the second detection line, the aforementioned method can still be used, that is, the arrangement points of the second optical fiber sensor 12 to be arranged are first uniformly marked on the inner wall of the frame 2061. Then the second optical fiber sensor 12 is adhered to the arrangement points by strain glue. Then the optical fiber 2 in the second detection line is wound on the inner wall of the frame 2061, and each second optical fiber sensor 12 is connected together and adhered to the inner wall of the frame 2061 by strain glue, and then the two ends of the optical fiber 2 in the second detection line are led out and connected with the light source demodulator 3.

[0074] Figure 5 The fourth arrangement mode of the deformation monitoring system provided by the embodiment of the present disclosure is shown in the figure, which is combined with Figure 5 The second detection line can also be arranged in the following manner:

[0075] Optionally, the second detection line is arranged one-to-one corresponding to the cavity. For any second detection line, the multiple second optical fiber sensors 12 in the second detection line are arranged on the corresponding inner side wall or top of the cavity along the circumferential direction of the cavity, and the multiple second optical fiber sensors 12 are connected with at least one of the inner wall of the frame 2061, the cross beam 2062 or the longitudinal beam 2063.

[0076] In the above implementation, by arranging one second detection line corresponding to each cavity, the number of test points can be increased, thereby improving the detection accuracy. Moreover, by connecting the second detection lines in parallel with each other, the connection and arrangement of each detection line can be facilitated.

[0077] In the embodiment, the cross beam 2062 is three parallel cross beams, the longitudinal beam 2063 is connected perpendicularly to the three cross beams 2062, and the two ends of the longitudinal beam 2063 are connected to the two cross beams 2062 farthest away from each other. Correspondingly, four cavities are formed. There are also four second detection lines, each of which forms a ring. Combined with Figure 5 When arranging the second detection line, the sensor can be arranged only on the cross beam 2062 and the longitudinal beam 2063. For example, the second detection line in the first cavity Figure 5Four second fiber optic sensors 12 are arranged on the first and second sidewalls (located in the lower left position), while no second fiber optic sensors 12 are arranged in other positions. The first and second sidewalls of the first cavity are formed by the first and second crossbeams. In the second cavity ( Figure 5 Four second fiber optic sensors 12 are respectively arranged on the first top wall, first side wall, and second side wall of the third cavity (located in the lower right position), while no second fiber optic sensors 12 are arranged in other positions. The first top wall of the second cavity is formed by the longitudinal beam 2063. The first side wall of the second cavity is formed by the second transverse beam. The second side wall of the second cavity is formed by the third transverse beam. In the third cavity ( Figure 5 Four second fiber optic sensors 12 are respectively arranged on the first top wall and the first side wall of the third cavity (located in the lower right position), while no second fiber optic sensors 12 are arranged in other positions. The first top wall of the third cavity is formed by the longitudinal beam 2063. The first side wall of the third cavity is formed by the third transverse beam 2062. In the fourth cavity ( Figure 5 Four second fiber optic sensors 12 are arranged on the first sidewall of the upper left position, while no second fiber optic sensors 12 are set in other positions. The first sidewall of the fourth cavity is the sidewall formed by the third crossbeam.

[0078] With this arrangement, an equal number of sensors can be placed on each crossbeam 2062 and longitudinal beam 2063, so that the deformation of the internal components 200 can be obtained by monitoring the crossbeams 2062 and longitudinal beams.

[0079] Optionally, the monitoring system also includes a splitter 5 and a combiner 6, both located at the center of the reinforcing frame 206 and connected to the intersection of the crossbeam 2062 and the longitudinal beam 2063. The splitter 5 has multiple output terminals, and the combiner 6 has multiple input terminals, with the multiple output terminals of the splitter 5 corresponding one-to-one with the multiple input terminals of the combiner 6.

[0080] Each output terminal of the splitter 5 is connected to the corresponding input terminal of the combiner 6 via a second detection line. The input terminal of the splitter 5 is connected to the output terminal of the light source demodulator 3, and the output terminal of the combiner 6 is connected to the input terminal of the light source demodulator 3.

[0081] In other words, when the splitter 5 and the combiner 6 are connected, the multiple output terminals of the splitter 5 are arranged one-to-one with the second detection line. The output terminal of the splitter 5 is connected to one end of the corresponding second detection line, the input terminal of the splitter 5 is connected to the output terminal of the light source demodulator 3, the output terminal of the combiner 6 is connected to the input terminal of the light source demodulator 3, and the other end of the second detection line is connected to the input terminal of the combiner 6 corresponding to the output terminal of the splitter 5.

[0082] In the above implementation, the shunt 5 is used to send the optical signals emitted by the light source demodulator 3 to the multiple second detection lines simultaneously in multiple channels, and the combiner 6 is used to transmit the reflected light signals in the multiple second detection lines to the light source demodulator 3 simultaneously.

[0083] In the above manner, the convergence of the multiple second detection lines in parallel with each other is achieved by using the optical path elements such as the shunt 5 and the combiner 6 at the intersection positions in the multiple sensing loops in parallel with each other, so that the complex detection line becomes simple, and the length and the number of bends of the detection line are greatly reduced, while the sensing efficiency is improved and the cost is reduced.

[0084] In the embodiment, the shunt 5 and the combiner 6 are stacked together in an up-down manner and are bonded or welded at the intersection positions of the cross beams 2062 and the longitudinal beams 2063 by structural adhesive.

[0085] When the second detection line is arranged in the above manner, the light source demodulator 3 is arranged on one of the cross beams 2062 or the longitudinal beams 2063, and an optical fiber 2 is led out from the output end of the light source demodulator 3 and connected to the shunt 5. The shunt 5 outputs four optical fibers 2 corresponding to four cavities. The four optical fibers 2 are respectively engraved with different numbers of second optical fiber sensors 12, and the second optical fiber sensors 12 are arranged at the monitoring point positions obtained after analysis. Then, the four optical fibers are converged into the combiner 6, and an optical fiber 2 is led out from the combiner 6 and connected to the light source demodulator 3, so that the arrangement of the detection line in the above manner is completed.

[0086] Figure 6 The fifth arrangement manner of the deformation monitoring system provided by the embodiment of the present disclosure is shown in the figure, which is combined with Figure 6 The second detection line can also be arranged in the following manner:

[0087] Alternatively, the multiple second optical fiber sensors 12 are arranged along the circumference of the frame 2061, and the multiple second optical fiber sensors 12 and the optical fiber 2 are connected to the outer wall of the frame 2061.

[0088] In the above implementation, the second detection line is arranged on the outer wall of the frame 2061, which can also monitor the deformation of multiple positions of the internal assembly 200. That is, when the internal assembly 200 deforms, the frame 2061 as the peripheral structure of the battery cell 201 will inevitably deform, and the second optical fiber sensors 12 arranged on the outer wall of the frame 2061 can monitor different positions.

[0089] Continuing to refer to Figure 6Optionally, the reinforcing frame 206 further comprises a plurality of lugs 2064, which are arranged along the circumference of the outer wall of the frame body 2061 and connected to the outer wall of the frame body 2061. The second fiber sensor 12 is located in the weld joint formed between one lug 2064 and the outer wall of the frame body 2061 and bonded thereto.

[0090] In the above implementation, the arrangement of the lugs 2064 is just able to form a groove between the outer wall of the reinforcing frame 206, so that the second fiber sensor 12 can be accommodated in the groove, so as to further reinforce the connection of the second fiber sensor 12 and protect the second fiber sensor 12.

[0091] In order to facilitate the arrangement of the second fiber sensor 12, the plurality of second fiber sensors 12 are arranged one-to-one with the plurality of lugs 2064, and the second fiber sensor 12 is bonded by strain glue in the weld joint formed between the corresponding lug 2064 and the outer wall of the frame body 2061.

[0092] In other embodiments, the second fiber sensor 12 does not necessarily correspond to the lug 2064 one-to-one, and two or three second fiber sensors 12 can also be arranged in one lug 2064 in order to increase the number of second fiber sensors 12.

[0093] Similarly, since the second detection line in the above manner is located outside the frame body 2061, and the fiber 2 needs to be connected with the light source demodulator 3 located in the reinforcing frame 206, in order to improve the overall airtightness between the fiber 2 in the second detection line and the reinforcing frame 206, the fiber 2 in the second detection line is also connected with the light source demodulator 3 through the fiber coupler 4. The fiber coupler 4 is also embedded in the side wall of the frame body 2061 through the plug.

[0094] That is, the arrangement of the fiber coupler 4 can lead the second detection line located outside the frame body 2061 back to the light source demodulator 3 inside the frame body 2061, and needs to be connected with the fiber coupler 4 after being connected with the light source demodulator 3.

[0095] When the second detection line is arranged in the above manner, the positions of the welds corresponding to each lifting lug 2064 are marked before arrangement (the long welds are marked uniformly, the short welds are marked in the middle of the welds, and the no-welds are marked uniformly at the fillets where the lifting lug 2064 is connected to the frame 2061). The surface of the weld of the lifting lug 2064 is smoothed by polishing, and then the weld strength is tested. After the test is passed, the second detection line is arranged. The light source demodulator 3 is placed inside the reinforcing frame 206, and a connecting hole is formed in the side wall of the frame 2061 for welding the fiber coupler 4. The optical fiber 2 is drawn out of the light source demodulator 3, passes through the fiber coupler 4 to the outside of the frame 2061, surrounds the frame 2061 once, and is connected to the second optical fiber sensor 12 arranged in each 10-lifting lug 2064 weld section. A certain amount of excess length is left between the adjacent two sensors to prevent the optical fiber from breaking due to large deformation. Finally, the optical fiber is wound back to the fiber coupler 4, and a fiber is drawn out of the fiber coupler 4 and connected to the light source demodulator 3, thereby completing the arrangement of the entire second detection line.

[0096] In the embodiments of the present disclosure, no matter which way is used to arrange the optical fiber sensor 1, the plurality of optical fiber sensors 1 can be arranged symmetrically, and the symmetry axis of the plurality of optical fiber sensors 1 is the cross beam 2062 or the longitudinal beam 2063. The light source demodulator 3 is connected to the symmetry axis of the plurality of optical fiber sensors 1. In this way, the two ends of the optical fiber 2 can be respectively connected to the light source demodulator 3, and the plurality of optical fiber sensors 1 can be arranged conveniently.

[0097] In the embodiments of the present disclosure, for the sake of clarity and intuition, the above Figures 2-6 only shows the case of having one detection line (either only the first detection line or only the second detection line). In actual setting, the arrangement forms shown in the above Figures 2-6 can be combined arbitrarily. The embodiments of the present disclosure do not limit this.

[0098] In the embodiments of the present disclosure, the structures of the optical fiber in the first detection line and the optical fiber in the second detection line are the same, which are single-mode optical fibers, and the corresponding core diameters are 3-100 microns, and the outer diameters are about 125-140 microns.

[0099] The optical fiber sensor 1 is a fiber Bragg grating sensor. The grating length of the grating of the optical fiber sensor 1 is 3-15 millimeters. In this way, the optical fiber sensor 1 can realize multiple measurement points by using a shorter grating, so that the monitoring position mapping is more accurate, and the arrangement of the optical fiber sensor 1 is more uniform.

[0100] Of course, the optical fiber sensor 1 can also be any one of a non-interferometric sensor and an interferometric sensor. That is, the optical fiber sensor can also be a sensor other than an optical fiber Bragg grating sensor, such as a Mach-Zehnder sensor and a Fabry-Perot sensor, etc. When the optical fiber sensor 1 is an interferometric sensor, the monitoring system can further include a polarizer.

[0101] In this embodiment, the total number of optical fiber sensors 1 is at least 16. That is, the monitoring positions are at least 16, so that the interior of the interior assembly 200 can be reliably monitored.

[0102] Of course, the more the number of arrangements of the optical fiber sensors 1, the higher the monitoring accuracy of the deformation of the interior assembly.

[0103] For example, in the same detection line, the spacing between two adjacent optical fiber sensors 1 along the extension direction of the optical fiber 2 is the same (the spacing can be 10-20% of the maximum value of the length, width, and height of the peripheral size of the interior assembly 200), and the center wavelengths of the plurality of optical fiber sensors 1 are the same. In this way, the optical fiber sensor is more convenient to manufacture, and the preparation efficiency of the optical fiber sensor is improved. In addition, in the same detection line, the optical fiber 2 between the two adjacent optical fiber sensors 1 should not be too tight, but should have a certain amount of slack to prevent the optical fiber from breaking when a larger deformation occurs.

[0104] The center wavelengths of the optical fiber sensors 1 are the same, and the light source demodulator 3 identifies and demodulates one by one according to the time when the reflected light reflected by each optical fiber sensor 1 reaches the light source demodulator 3. That is, the light source demodulator 3 emits one light signal, and each optical fiber sensor on the optical fiber 2 reflects one reflected light signal. Since there is a delay in the reflection of light by each optical fiber sensor 1 in the optical fiber, the light source demodulator 3 can identify and locate the optical fiber sensor 1 from which the reflected light signal comes according to the size of the time delay of receiving the reflected light signal.

[0105] The arrangement of the optical fiber sensors 1 can be freely set. As long as it can correspond to monitoring different positions in the interior of the interior assembly 200, the present disclosure does not limit the arrangement of the optical fiber sensors 1.

[0106] In this embodiment, the detection line is arranged in the interior of the interior assembly 200 in a reasonable manner. In this way, the shape of the interior of the interior assembly 200 can be monitored in real time. If the bottom of the vehicle body is subjected to a load such as a ball hit or a bottom scratch, such an arrangement scheme can obtain accurate position information of the damaged part after being hit, so as to estimate whether a part of the battery cell 201 in the interior assembly 200 has a position deviation, and greatly improve the monitoring accuracy.

[0107] Moreover, compared with other types of strain sensors, the optical fiber sensor 1 has the advantages of small size, simple monitoring loop arrangement, small transmission loss, flexible monitoring point setting, large information transmission amount, high sensitivity, and anti-electromagnetic interference, etc. In addition, from the properties of the optical fiber itself, the main constituent material of the optical fiber is silicon dioxide and some silicon dioxide compounds, so the optical fiber itself has the advantages of good insulation performance, resistance to various types of corrosion, stable chemical properties, radiation resistance, etc. Moreover, the optical fiber has certain protective measures outside, which improves the tensile strength of the optical fiber, so that the optical fiber can be used in various types of detection environments, and further makes the monitoring system convenient to arrange in the internal assembly 200.

[0108] In another aspect, the embodiments of the present disclosure also provide a power battery, see Figure 1 The power battery comprises a monitoring system, a box body 100, and an internal assembly 200, the internal assembly 200 is located in the box body 100, the deformation monitoring system is located in the box body 100 and connected with the internal assembly 200. The deformation monitoring system is the deformation monitoring system mentioned above.

[0109] The above power battery has the same beneficial effects as described above, which will not be repeated here.

[0110] The above only describes optional embodiments of the present disclosure, and does not limit the present disclosure. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A deformation monitoring system for a power battery, characterized in that, The power battery includes a housing and internal components, with the internal components connected to the housing. The deformation monitoring system includes at least one detection line and a light source demodulator. Each detection line includes multiple fiber optic sensors and optical fibers. The optical fibers connect the multiple fiber optic sensors in series. The multiple fiber optic sensors are spaced apart inside the housing and connected to the internal components. The light source demodulator is located inside the housing and connected to the internal components. The light source demodulator is connected to both ends of each of the detection lines. The internal components include multiple battery cells, thermally conductive structural adhesive, liquid cooling plate, and reinforcing frame. The battery cells, thermally conductive structural adhesive, and liquid cooling plate are sequentially connected along the direction from the top to the bottom of the housing. The reinforcing frame includes a frame body, at least one crossbeam and a longitudinal beam. The reinforcing frame is located inside the housing and on the side of the liquid cooling plate facing the battery cell. The frame body is connected to the inner wall of the housing body. The crossbeam and the longitudinal beam are both located inside the frame body, and the at least one crossbeam is connected to the frame body. The at least one crossbeam is intersected with the longitudinal beam and defines multiple cavities with the frame body and the liquid cooling plate. The multiple battery cells correspond one-to-one with the multiple cavities. The battery cells are connected to the liquid cooling plate in the corresponding cavity through the thermally conductive structural adhesive. The light source demodulator is connected to the crossbeam or the longitudinal beam; The at least one detection line includes at least one of a first detection line and a second detection line, wherein the plurality of fiber optic sensors in the first detection line are all first fiber optic sensors, and the plurality of first fiber optic sensors are connected to the liquid cooling plate. The multiple fiber optic sensors in the second detection line are all second fiber optic sensors, and the multiple second fiber optic sensors are connected to the reinforcing frame; Multiple first optical fiber sensors in the first detection line are connected at intervals to the upper surface of the liquid cooling plate facing the battery cell. The middle part of the optical fiber in the first detection line is encapsulated in the thermally conductive structural adhesive, and the two ends of the optical fiber in the first detection line are located outside the thermally conductive structural adhesive. In the second detection circuit, multiple second fiber optic sensors are arranged at circumferential intervals along the inner wall of the frame, and all of the multiple second fiber optic sensors are connected to the inner wall of the frame.

2. The deformation monitoring system according to claim 1, characterized in that, The liquid cooling plate has a cooling groove on the lower surface of the bottom guard plate facing the bottom of the internal component for the flow of coolant. Multiple first fiber optic sensors in the first detection line are connected at intervals within the cooling tank, and the optical fibers in the first detection line are arranged along the cooling tank.

3. The deformation monitoring system according to claim 1, characterized in that, The second detection line is arranged in a one-to-one correspondence with the cavity. For any second detection line, a plurality of second fiber optic sensors in the second detection line are arranged at intervals along the circumference of the corresponding cavity. The plurality of second fiber optic sensors are connected to at least one of the inner wall of the frame, the crossbeam or the longitudinal beam.

4. The deformation monitoring system according to claim 3, characterized in that, The monitoring system also includes a splitter and a combiner, both of which are located at the center of the reinforcing frame and are connected to the intersection of the crossbeam and the longitudinal beam. The splitter has multiple output terminals, and the combiner has multiple input terminals. The multiple output terminals of the splitter are arranged in a one-to-one correspondence with the multiple input terminals of the combiner. Each output terminal of the splitter is connected to the corresponding input terminal of the combiner through a second detection line. The input terminal of the splitter is connected to the output terminal of the light source demodulator, and the output terminal of the combiner is connected to the input terminal of the light source demodulator.

5. The deformation monitoring system according to claim 1, characterized in that, The plurality of second fiber optic sensors are arranged at circumferential intervals along the frame, and the plurality of second fiber optic sensors and the fiber are all connected to the outer wall of the frame.

6. The deformation monitoring system according to claim 5, characterized in that, The reinforcing frame also includes a plurality of lifting lugs, which are arranged at circumferential intervals along the outer periphery of the frame and connected to the outer wall of the frame. The second fiber optic sensor is located within a weld formed between one of the lifting lugs and the outer wall of the frame, and is bonded to the weld.

7. A power battery, characterized in that, The power battery includes a deformation monitoring system, a housing, and internal components. The internal components are located inside the housing, and the deformation monitoring system is located inside the housing and connected to the internal components. The monitoring system is the deformation monitoring system according to any one of claims 1 to 6.

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