An adaptive compensation lithium battery state of charge monitoring device

Abstract

The application relates to a self-adaptive compensation lithium battery state-of-charge monitoring device, which comprises a support (1), a water tank (2), a water-immersed ultrasonic emission transducer (3), a water-immersed ultrasonic receiving transducer (4), a battery to be measured (5), a function generator (6), an ultrasonic signal collector (7), an auxiliary detection unit (8), an optical power meter (9) and a data processor (10). The device can compensate the influence of temperature and stress on ultrasonic signals, so as to further improve the precision of ultrasonic detection of the battery state-of-charge.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, specifically to an adaptive compensation lithium battery state of charge monitoring device. Background Technology

[0002] With the widespread adoption of electric vehicles and mobile devices, lithium-ion batteries, as representative of rechargeable batteries, are widely used in energy storage. The state of charge (SOC) of a battery is one of the key parameters in battery management systems, directly impacting the driving range of electric vehicles and the usage time of mobile devices. Currently, battery SOC characterization methods cannot directly reflect the impact of changes in the battery's internal structure on SOC, resulting in significant detection errors. Acoustic parameters, as sensitive indicators of changes in the battery's internal structure and state, are increasingly attracting researchers' attention. Ultrasonic technology can determine changes in material properties such as thickness and elastic modulus. Since the charging and discharging process directly affects the thickness and elastic modulus of the positive and negative electrodes, ultrasonic technology has been widely applied in battery state detection and other fields in recent years. However, factors such as temperature and stress can affect the accuracy of ultrasonic signals, thus impacting the accurate monitoring of the battery's state of charge. Summary of the Invention

[0003] The purpose of this application is to propose an adaptive compensation lithium battery state of charge monitoring device to improve the accuracy of battery state of charge detection.

[0004] To achieve the above objectives, this application provides an adaptive compensation method for monitoring the state of charge of a lithium battery, comprising: a support (1), a water tank (2), a water-immersed ultrasonic transmitting transducer (3), a water-immersed ultrasonic receiving transducer (4), a battery under test (5), a function generator (6), an ultrasonic signal acquisition unit (7), an auxiliary detection unit (8), an optical power meter (9), and a data processor (10); the support (1) is disposed in the water tank (2); the water-immersed ultrasonic transmitting transducer (3), the water-immersed ultrasonic receiving transducer (4), and the battery under test (5) are disposed on the support (1), and the... The water-immersed ultrasonic transmitting transducer (3) and the water-immersed ultrasonic receiving transducer (4) are located on the front and back of the battery under test (5); the water tank (2) is filled with an ultrasonic coupling medium that submerges the water-immersed ultrasonic transmitting transducer (3), the water-immersed ultrasonic receiving transducer (4), and the battery under test (5); the water-immersed ultrasonic transmitting transducer (3) is connected to the function generator (6); the water-immersed ultrasonic receiving transducer (4), the ultrasonic signal acquisition unit (7), and the data processor (10) are connected in sequence; the auxiliary detection unit (8), the optical power meter (9), and the data processor (10) are connected in sequence.

[0005] The auxiliary detection unit (8) includes a scanning laser (81), an optical fiber isolator (82), an optical fiber coupler (83), a first optical fiber circulator (84), a second optical fiber circulator (85), a first fiber grating (86), and a second fiber grating (87). The scanning laser (81), the optical fiber isolator (82), and the optical fiber coupler (83) are connected in sequence. The first optical fiber circulator (84) and the second optical fiber circulator (85) are both connected to the optical fiber coupler (83). The first fiber grating (86) and the second fiber grating (87) are disposed on the battery under test. The first fiber grating (86) and the second fiber grating (87) are both connected to the optical power meter (9). The scanning laser (81) is also connected to the data processor (10).

[0006] Furthermore, the water-immersion ultrasonic transmitting transducer (3) is used to transmit ultrasonic signals. The ultrasonic signals pass through the battery under test and are received by the water-immersion ultrasonic receiving transducer (4). The ultrasonic signal acquisition device (7) acquires the ultrasonic signals received by the water-immersion ultrasonic receiving transducer (4) and transmits them to the data processor (10) for calculation and processing.

[0007] The scanning laser (81) is used to generate a swept laser. The swept laser passes through the fiber isolator (82) and enters the fiber coupler (83). The fiber coupler (83) is used to split the swept laser into two beams and send them to the first fiber circulator (84) and the second fiber circulator (85) respectively. The first fiber circulator (84) and the second fiber circulator (85) send the received light into the first fiber grating (86) and the second fiber grating (87) respectively. The first fiber grating (86) and the second fiber grating (87) reflect part of the laser power back to the first fiber circulator (84) and the second fiber circulator (85). The first fiber circulator (84) and the second fiber circulator (85) output the reflected laser power to the optical power meter (9). The optical power meter (9) is used to detect the laser power output from the first fiber circulator (84) and the second fiber circulator (85) to obtain the optical power signal, and output it to the data processor (10) for calculation and processing.

[0008] The data processor is used to process the ultrasonic signal output by the ultrasonic signal acquisition device (7) and the optical power signal output by the optical power meter (9) to obtain the state of charge information of the battery under test.

[0009] Furthermore, the data processor is specifically used to extract the ultrasonic feature value of the ultrasonic signal output by the ultrasonic signal collector (7) and the optical feature value of the optical power signal output by the optical power meter (9), and input the ultrasonic feature value and the optical feature value into a pre-trained convolutional neural network model for processing to obtain the state of charge information of the battery under test;

[0010] The parameters of the convolutional neural network model include: a kernel size of 3, a kernel stride of 1, a ReLU activation function used in the convolutional layer, a single output layer neuron, and a sigmoid activation function.

[0011] Further, the data processor (10) acquires the laser wavelength of the laser source, determines the reflection center wavelengths of the first fiber grating (86) and the second fiber grating (87) based on the laser wavelength, and records the drift value Δ of the reflection center wavelength of the first fiber grating (86). l 1. Record the drift value Δ of the reflection center wavelength of the second fiber grating (87). l 2. The temperature change Δ T for:

[0012] Δ T = K T Δ l 1

[0013] strain change Δ e for:

[0014] Δ e = S ε (Δ l 2-Δ l 1),

[0015] In the formula K T , S ε These are intrinsic constants related to the inherent properties of the optical fiber itself.

[0016] Furthermore, the data processor (10) is also used for the temperature change Δ T、 strain change Δ e The ultrasonic characteristic values ​​are calibrated to eliminate the interference of battery temperature and stress on the ultrasonic signal.

[0017] Furthermore, the first fiber grating (86) is directly bonded to the surface of the battery under test; the second fiber grating (87) is placed in a metal sleeve (88), which is bonded to the surface of the battery under test.

[0018] Furthermore, the ultrasonic feature values ​​extracted by the data processor (10) include at least the amplitude of the ultrasonic signal. A Flight time T、 frequency oh Hilbert transform peak H A Ringing count m Maximum instantaneous energy E Information entropy H X Energy entropy S At least one of them.

[0019] Furthermore, the ultrasonic coupling agent includes at least one of dimethyl silicone oil, epoxy resin, and agar; wherein the mass ratio of dimethyl silicone oil is between 50% and 75%, the mass ratio of epoxy resin is between 25% and 45%, and the mass ratio of agar is between 5% and 15%.

[0020] Furthermore, the center frequency of the ultrasonic transducer is between 0.2 MHz and 5 MHz.

[0021] The embodiments of this application have the following beneficial effects:

[0022] Using optical fibers as sensors enables high-precision monitoring of temperature and stress. Moreover, optical fiber sensors have advantages such as small size and resistance to electromagnetic interference, which can reduce crosstalk between ultrasonic sensors and optical fiber sensors. By extracting and analyzing the feature values ​​of ultrasonic signals through a data processor and compensating for the influence of temperature and stress on ultrasonic signals, the accuracy of ultrasonic detection of battery state of charge can be further improved. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings required in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a structural diagram of an adaptive compensation lithium battery state-of-charge monitoring device according to an embodiment of this application.

[0025] Figure 2 This is a structural diagram of the auxiliary detection unit in the embodiments of this application.

[0026] Marked in the image:

[0027] 1 is a support; 2 is a water tank; 3 is a water-immersed ultrasonic transmitting transducer; 4 is a water-immersed ultrasonic receiving transducer; 5 is the battery under test; 6 is a function generator; 7 is an ultrasonic signal acquisition device; 8 is an auxiliary detection unit; 9 is an optical power meter; 10 is a data processor; 81 is a scanning laser; 82 is an optical fiber isolator; 83 is an optical fiber coupler; 84 is a first optical fiber circulator; 85 is a second optical fiber circulator; 86 is a first fiber grating; 87 is a second fiber grating; 88 is a metal sleeve. Detailed Implementation

[0028] The detailed description of the accompanying drawings is intended to illustrate some embodiments of this application and is not intended to represent only the forms in which this application can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments intended to be included within the spirit and scope of this application.

[0029] See Figure 1 One embodiment of this application provides an adaptive compensation method for monitoring the state of charge of a lithium battery, comprising: a support 1, a water tank 2, a water-immersed ultrasonic transmitting transducer 3, a water-immersed ultrasonic receiving transducer 4, a battery under test 5, a function generator 6, an ultrasonic signal acquisition unit 7, an auxiliary detection unit 8, an optical power meter 9, and a data processor 10; the support 1 is disposed in the water tank 2; the water-immersed ultrasonic transmitting transducer 3, the water-immersed ultrasonic receiving transducer 4, and the battery under test 5 are disposed on the support 1, and the water-immersed ultrasonic transmitting transducer 6, the water-immersed ultrasonic receiving transducer 4, and the battery under test 5 are disposed on the support 1, and the water-immersed ultrasonic transmitting transducer 6, the water-immersed ultrasonic receiving transducer 7, the ultrasonic receiving transducer 8, the ultrasonic receiving transducer 9, and the ultrasonic receiving transducer 10 are disposed in the water tank 2; the water-immersed ultrasonic transmitting transducer 6, the water-immersed ultrasonic receiving transducer 7, the ultrasonic receiving transducer 8, the ultrasonic receiving transducer 9, and the ultrasonic receiving transducer 10 are disposed in the water tank 2; the water-immersed ultrasonic transmitting transducer 6, the water-immersed ultrasonic receiving transducer 7, the ultrasonic receiving transducer 8, the ultrasonic receiving transducer 9, and the ultrasonic receiving transducer 10 are disposed in the water tank 2; the water-immersed ultrasonic receiving ...9, the water-immersed ultrasonic receiving transducer 1, and the ultrasonic receiving transducer 10, the water-immersed Transducer 3 and immersion ultrasonic receiver 4 are located on the front and back of the battery under test 5, respectively. The water tank 2 contains an ultrasonic coupling medium that submerges the immersion ultrasonic transmitter 3, immersion ultrasonic receiver 4, and battery under test 5, which can improve the signal-to-noise ratio. The immersion ultrasonic transmitter 3 is connected to the function generator 6. The immersion ultrasonic receiver 4, ultrasonic signal acquisition unit 7, and data processor 10 are connected in sequence. The auxiliary detection unit 8, optical power meter 9, and data processor 10 are connected in sequence.

[0030] See Figure 2 The auxiliary detection unit 8 includes a scanning laser 81, an optical fiber isolator 82, an optical fiber coupler 83, a first optical fiber circulator 84, a second optical fiber circulator 85, a first fiber grating 86, and a second fiber grating 87. The scanning laser 81, optical fiber isolator 82, and optical fiber coupler 83 are connected in sequence. The first optical fiber circulator 84 and the second optical fiber circulator 85 are both connected to the optical fiber coupler 83. The first fiber grating 86 and the second fiber grating 87 are disposed on the battery under test and are both connected to the optical power meter 9. The scanning laser 81 is also connected to the data processor 10.

[0031] Furthermore, the water-immersed ultrasonic transmitting transducer 3 is used to transmit ultrasonic signals. The ultrasonic signals pass through the battery under test and are received by the water-immersed ultrasonic receiving transducer 4. The ultrasonic signal acquisition device 7 acquires the ultrasonic signals received by the water-immersed ultrasonic receiving transducer 4 and transmits them to the data processor 10 for calculation and processing. Both the water-immersed ultrasonic transmitting transducer 3 and the water-immersed ultrasonic receiving transducer 4 are 2 cm away from the battery. The ultrasonic signals emitted by the water-immersed ultrasonic transmitting transducer 3 pass through the battery and interact with the internal materials of the battery, so that the ultrasonic signals carry the characteristic information of the battery and are received by the water-immersed ultrasonic receiving transducer 4 located on the back of the battery.

[0032] The scanning laser 81 generates a swept laser beam, which passes through the fiber isolator 82 and enters the fiber coupler 83. The fiber coupler 83 splits the swept laser beam into two beams, which are then fed into the first fiber circulator 84 and the second fiber circulator 85, respectively. The first fiber circulator 84 and the second fiber circulator 85 send the received light into the first fiber grating 86 and the second fiber grating 87, respectively. The first fiber grating 86 and the second fiber grating 87 reflect a portion of the laser power back to the first fiber circulator 84 and the second fiber circulator 85. The first fiber circulator 84 and the second fiber circulator 85 output the reflected laser power to the optical power meter 9. The optical power meter 9 detects the laser power output from the first fiber circulator 84 and the second fiber circulator 85 to obtain an optical power signal, which is then output to the data processor 10 for calculation and processing.

[0033] The data processor is used to process the ultrasonic signal output by the ultrasonic signal acquisition device 7, the frequency-sweeping laser output by the scanning laser 81, and the optical power signal output by the optical power meter 9 to obtain the state of charge information of the battery under test.

[0034] Furthermore, the data processor is specifically used to extract the ultrasonic feature value of the ultrasonic signal output by the ultrasonic signal acquisition device 7 and the optical feature value of the optical power signal output by the optical power meter 9, and input the ultrasonic feature value and the optical feature value into a pre-trained convolutional neural network model for processing to obtain the state of charge information of the battery under test.

[0035] The parameters of the convolutional neural network model include: a kernel size of 3, a kernel stride of 1, a ReLU activation function used in the convolutional layer, a single output layer neuron, and a sigmoid activation function.

[0036] Further, the data processor 10 acquires the laser wavelength of the laser source, determines the reflection center wavelengths of the first fiber grating 86 and the second fiber grating 87 based on the laser wavelength, and records the drift value Δ of the reflection center wavelength of the first fiber grating 86. l 1. Record the drift value Δ of the reflection center wavelength of the second fiber grating 87. l 2. The temperature change Δ T for:

[0037] Δ T = K T Δ l 1

[0038] strain change Δ e for:

[0039] Δ e = S ε (Δ l 2-Δ l 1),

[0040] In the formula K T , S ε These are intrinsic constants related to the inherent properties of the optical fiber itself.

[0041] When the optical power meter detects the maximum power, the data processor 10 records the laser wavelength of the scanning laser 81. This wavelength is the reflection center wavelength of the sensing grating. When the surface temperature or strain of the battery changes, the reflection center wavelength of the fiber optic grating will change. By demodulating the wavelength, information such as battery temperature and stress can be obtained.

[0042] Furthermore, the data processor 10 is also used for the temperature change Δ T、 strain change Δ e The ultrasonic characteristic values ​​are calibrated to eliminate the interference of battery temperature and stress on the ultrasonic signal.

[0043] Furthermore, the first fiber grating 86 is directly bonded to the surface of the battery under test; the second fiber grating 87 is placed in a metal sleeve 88, which is bonded to the surface of the battery under test.

[0044] Furthermore, the ultrasonic feature values ​​extracted by the data processor 10 include at least the amplitude of the ultrasonic signal. A Flight time T、 frequency oh Hilbert transform peak H A Ringing count m Maximum instantaneous energyE Information entropy H X Energy entropy S At least one of them.

[0045] Furthermore, the ultrasonic coupling agent includes at least one of dimethyl silicone oil, epoxy resin, and agar; wherein the mass ratio of dimethyl silicone oil is between 50% and 75%, the mass ratio of epoxy resin is between 25% and 45%, and the mass ratio of agar is between 5% and 15%. The above proportions can match the acoustic impedance of the optical fiber and the optical fiber sheath, improve the ultrasonic detection signal, and increase the signal-to-noise ratio.

[0046] Furthermore, the center frequency of the ultrasonic transducer is between 0.2 MHz and 5 MHz.

[0047] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technological improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An adaptive compensation lithium battery state-of-charge monitoring device, characterized in that, include: The system comprises a support (1), a water tank (2), a water-immersed ultrasonic transmitting transducer (3), a water-immersed ultrasonic receiving transducer (4), a battery under test (5), a function generator (6), an ultrasonic signal acquisition unit (7), an auxiliary detection unit (8), an optical power meter (9), and a data processor (10). The support (1) is located in the water tank (2). The water-immersed ultrasonic transmitting transducer (3), the water-immersed ultrasonic receiving transducer (4), and the battery under test (5) are located on the support (1). The acoustic receiving transducer (4) is located on the front and back of the battery under test (5); the water tank (2) contains an ultrasonic coupling medium-submerged water-immersed ultrasonic transmitting transducer (3), a water-immersed ultrasonic receiving transducer (4), and the battery under test (5); the water-immersed ultrasonic transmitting transducer (3) is connected to the function generator (6); the water-immersed ultrasonic receiving transducer (4), the ultrasonic signal acquisition unit (7), and the data processor (10) are connected in sequence; the auxiliary detection unit (8), the optical power meter (9), and the data processor (10) are connected in sequence. The auxiliary detection unit (8) includes a scanning laser (81), an optical fiber isolator (82), an optical fiber coupler (83), a first optical fiber circulator (84), a second optical fiber circulator (85), a first fiber grating (86), and a second fiber grating (87). The scanning laser (81), the optical fiber isolator (82), and the optical fiber coupler (83) are connected in sequence. The first optical fiber circulator (84) and the second optical fiber circulator (85) are both connected to the optical fiber coupler (83). The first fiber grating (86) and the second fiber grating (87) are disposed on the battery under test. The first fiber grating (86) and the second fiber grating (87) are both connected to the optical power meter (9). The scanning laser (81) is also connected to the data processor (10). The water-immersion ultrasonic transmitting transducer (3) is used to transmit ultrasonic signals. The ultrasonic signals pass through the battery under test and are received by the water-immersion ultrasonic receiving transducer (4). The ultrasonic signal acquisition device (7) acquires the ultrasonic signals received by the water-immersion ultrasonic receiving transducer (4) and transmits them to the data processor (10) for calculation and processing. The scanning laser (81) is used to generate a swept laser. The swept laser passes through the fiber isolator (82) and enters the fiber coupler (83). The fiber coupler (83) is used to split the swept laser into two beams and send them to the first fiber circulator (84) and the second fiber circulator (85) respectively. The first fiber circulator (84) and the second fiber circulator (85) send the received light into the first fiber grating (86) and the second fiber grating (87) respectively. The first fiber grating (86) and the second fiber grating (87) reflect part of the laser power back to the first fiber circulator (84) and the second fiber circulator (85). The first fiber circulator (84) and the second fiber circulator (85) output the reflected laser power to the optical power meter (9). The optical power meter (9) is used to detect the laser power output from the first fiber circulator (84) and the second fiber circulator (85) to obtain the optical power signal, and output it to the data processor (10) for calculation and processing. The data processor is used to process the ultrasonic signal output by the ultrasonic signal acquisition device (7) and the optical power signal output by the optical power meter (9) to obtain the state of charge information of the battery under test. The data processor (10) acquires the laser wavelength of the sweeping laser source, determines the reflection center wavelengths of the first fiber grating (86) and the second fiber grating (87) based on the laser wavelength, and records the drift value Δ of the reflection center wavelength of the first fiber grating (86). λ 1. Record the drift value Δ of the reflection center wavelength of the second fiber grating (87). λ 2. The temperature change Δ T for: D T = K T D λ 1 strain change Δ ε for: D ε = S ε (D λ 2-D λ 1), In the formula K T , S ε These are intrinsic constants related to the inherent properties of the optical fiber itself; The data processor (10) is also used to calculate the temperature change Δ T、 strain change Δ ε The ultrasonic characteristic values ​​are calibrated to eliminate the interference of battery temperature and stress on the ultrasonic signal.

2. The adaptive compensation lithium battery state-of-charge monitoring device according to claim 1, characterized in that, The data processor is specifically used to extract the ultrasonic feature value of the ultrasonic signal output by the ultrasonic signal collector (7) and the optical feature value of the optical power signal output by the optical power meter (9), and input the ultrasonic feature value and the optical feature value into a pre-trained convolutional neural network model for processing to obtain the state of charge information of the battery under test. The parameters of the convolutional neural network model include: a kernel size of 3, a kernel stride of 1, a ReLU activation function used in the convolutional layer, a single output layer neuron, and a sigmoid activation function.

3. The adaptive compensation lithium battery state-of-charge monitoring device as described in any one of claims 1 to 2, characterized in that, The first fiber grating (86) is directly bonded to the surface of the battery under test; the second fiber grating (87) is placed in a metal sleeve (88), which is bonded to the surface of the battery under test.

4. The adaptive compensation lithium battery state-of-charge monitoring device as described in any one of claims 1 to 2, characterized in that, The ultrasonic feature values ​​extracted by the data processor (10) include at least the amplitude of the ultrasonic signal. A Flight time T、 frequency ω Hilbert transform peak H A Ring count m Maximum instantaneous energy E Information entropy H X Energy entropy S At least one of them.

5. The adaptive compensation lithium battery state-of-charge monitoring device as described in any one of claims 1 to 2, characterized in that, The ultrasonic coupling agent includes at least one of dimethyl silicone oil, epoxy resin, and agar; wherein the mass ratio of dimethyl silicone oil is between 50% and 75%, the mass ratio of epoxy resin is between 25% and 45%, and the mass ratio of agar is between 5% and 15%.

6. The adaptive compensation lithium battery state-of-charge monitoring device according to any one of claims 1 to 2, characterized in that, The center frequency of the ultrasonic transducer is between 0.2 MHz and 5 MHz.

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