Wireless microsystem for real-time monitoring of in-situ pressure and temperature inside lithium battery and manufacturing method

Abstract

The present invention relates to the technical field of sensors and microsystems. Disclosed are a wireless microsystem for real-time monitoring of in-situ pressure and temperature inside a lithium battery and a manufacturing method. The wireless microsystem comprises a sound wave receiving module, a working condition sensitive module and a sound wave transmitting module which are connected in sequence and manufactured on the basis of MEMS technology, so that the wireless microsystem can be non-destructively implanted into a lithium battery, wherein the sound wave receiving module is configured to obtain a first electrical signal on the basis of a received first sound wave signal corresponding to a first preset resonant frequency; the working condition sensitive module is configured to couple an in-situ working condition state of a cell to the first electrical signal to obtain a second electrical signal; and the sound wave transmitting module is configured to transmit a second sound wave signal on the basis of an electrical signal component that meets a second preset resonant frequency, so that an external sound wave receiver determines the in-situ working condition state of the cell on the basis of the second sound wave signal. In this way, the input of wireless energy and the real-time output of the in-situ working condition state are realized, thereby facilitating real-time monitoring of the state of individual cells of the lithium battery and benefiting practical production applications.

Description

Wireless microsystem for real-time monitoring of in-situ pressure and temperature inside lithium batteries and its manufacturing method Technical Field

[0001] The present invention relates to the technical field of sensors and microsystems, and in particular to a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery and a manufacturing method thereof. Background Art

[0002] Lithium-ion batteries, also known as lithium batteries, have the advantages of high energy density, long cycle life, no memory effect and good safety. They have been widely used in portable electronic products and electric vehicles. However, the battery life and safety issues of lithium batteries have always been obstacles in their application. Specifically, in order to improve the charging and discharging efficiency, ensure the safety of system operation, and reduce the system operating costs, it is necessary to accurately sense the working status of lithium batteries. Lithium batteries with abnormal status will affect the stability and safety of the system, which will manifest as reduced capacity, increased heat generation, bulging, etc.; especially for complex systems composed of multiple single cells in series and parallel, the difference in status between single cells will not only accelerate the attenuation of battery capacity, but may even induce serious safety problems such as thermal runaway due to individual batteries experiencing large charge and discharge rates or overcharge and over-discharge. Currently, the following three methods are mainly used to control lithium batteries:

[0003] The first method is to monitor the external characteristics of the lithium battery surface, such as temperature, voltage, current and internal resistance, and then evaluate the working condition of the battery. However, this is only information obtained at the equipment level. In essence, the lithium battery is a closed and complex system. The changes in characteristic quantities such as temperature and pressure caused by the chemical reactions inside the battery take a certain amount of time to be transmitted from the inside of the battery to the outside. It is difficult to accurately know the working status of the lithium battery by relying solely on the monitored external characteristic information.

[0004] The second method is to insert a fiber optic Fabry-Perot sensor or a Bragg grating fiber optic sensor into the lithium battery, passing through the center of the battery cell, in order to monitor the internal working conditions of the lithium battery. However, this through-hole placement method is not suitable for application scenarios of lithium battery packs such as new energy vehicles, and it is costly and difficult to maintain.

[0005] A third approach involves custom-implanting commercial pressure sensors into large prismatic lithium batteries and using wires to extract pressure signals, thereby measuring internal pressure during the battery's charge and discharge process. However, this invasive implantation method is difficult to use with small cylindrical lithium batteries and significantly impacts battery performance.

[0006] Therefore, how to design a wireless sensing microsystem technology solution for in-situ online monitoring of the internal working status of lithium batteries to obtain an intelligent battery that can self-sense the internal working status of the battery is an urgent problem to be solved.

[0007] Summary of the Invention

[0008] The problem solved by the present invention is to provide a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery and a manufacturing method. The wireless microsystem can be non-destructively implanted inside various lithium batteries, realizing wireless energy input and real-time output of in-situ working conditions, which is beneficial for real-time monitoring of the status of single cells of the lithium battery and is beneficial for practical production applications.

[0009] To solve the above problems, the present invention provides a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery, which is applied to the interior of a single battery cell. The wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery includes an acoustic wave receiving module, a working condition sensitive module, and an acoustic wave transmitting module manufactured based on MEMS technology.

[0010] The sound wave receiving module, the working condition sensitive module and the sound wave transmitting module are connected in sequence;

[0011] The sound wave receiving module is used to convert the first sound wave signal received by the external sound wave transmitter and corresponding to the first preset resonant frequency into an acoustic-electrical signal to obtain a first electrical signal;

[0012] The operating condition sensitive module is used to couple the in-situ operating condition inside the single battery cell to the first electrical signal to obtain a second electrical signal;

[0013] The acoustic wave transmitting module is used to convert the electrical signal component in the second electrical signal that meets the second preset resonant frequency into an electrical-acoustic signal to emit a second acoustic wave signal, so that an external acoustic wave receiver can determine the in-situ operating state based on the received second acoustic wave signal, wherein the first preset resonant frequency is different from the second preset resonant frequency.

[0014] The beneficial effects of the present invention are as follows: the wireless microsystem can be non-destructively implanted inside various lithium batteries, thereby effectively sensing the in-situ working state inside the single cell; the difference between the first preset resonant frequency and the second preset resonant frequency ensures that the acoustic wave transmission module is not interfered with by the first acoustic wave signal and is more conducive to the subsequent determination of the in-situ working state, realizing the input of wireless energy and the real-time output of the in-situ working state, which is conducive to real-time monitoring of the state of the single cell of the lithium battery and is conducive to practical production applications.

[0015] Furthermore, the sound wave receiving module is a sound wave transducer, and the sound wave transducer includes a structural subunit, and the structural subunit includes an upper electrode layer, a first piezoelectric film, and a lower electrode layer arranged in sequence from top to bottom;

[0016] The second preset resonant frequency is determined according to the geometric dimensions of the first piezoelectric film and the thickness of the structural subunit, so that the second preset resonant frequency is different from the first preset resonant frequency.

[0017] In this solution, simulation is performed by adjusting the geometric dimensions of the first piezoelectric film and the thickness of the structural subunit, thereby effectively determining the second preset resonant frequency, ensuring that the second preset resonant frequency is different from the first preset resonant frequency, so that the setting of the second preset resonant frequency is conducive to signal separation and processing.

[0018] Furthermore, each of the structural subunits is connected in sequence to form an N*M array structure, where N is an integer greater than 1, M is an integer greater than 1, and N*M=the total number of the structural subunits.

[0019] In this solution, a larger first electrical signal can be obtained through the above-mentioned setting, thereby improving the efficiency of acoustic-electrical signal conversion.

[0020] Furthermore, the first acoustic wave signal is an acoustic wave signal having a first-order vibration mode resonance frequency consistent with the first piezoelectric film.

[0021] In this solution, the above-mentioned setting realizes the effective feeding of the first sound wave signal.

[0022] Furthermore, the operating condition sensitive module includes a second piezoelectric film and a pressure sensitive sensing module arranged on the second piezoelectric film for sensing the in-situ pressure condition inside the single cell, and / or a heat sensitive sensing module for sensing the in-situ temperature condition inside the single cell; and when the operating condition sensitive module includes the pressure sensitive sensing module and the heat sensitive sensing module, the pressure sensitive sensing module and the heat sensitive sensing module are arranged in parallel.

[0023] In this solution, the above-mentioned settings can ensure that the temperature and / or pressure conditions inside the single battery cell can be sensed in a timely and effective manner, so that corresponding treatment solutions can be taken subsequently.

[0024] Furthermore, the thermal sensing module includes a first circuit structure composed of a plurality of thermistors whose resistance changes with the temperature inside the single cell, so that the second electrical signal changes with the temperature inside the single cell.

[0025] In this solution, the first circuit structure composed of thermistors is used to reliably couple the temperature condition inside the single cell to the first electrical signal to obtain the second electrical signal.

[0026] Furthermore, the pressure sensing module includes a second circuit structure composed of a plurality of piezoresistors whose resistance changes with the pressure inside the single cell, so that the second electrical signal changes with the pressure inside the single cell.

[0027] In this solution, the second circuit structure composed of varistors is used to reliably couple the pressure condition inside the single cell to the first electrical signal to obtain the second electrical signal.

[0028] Furthermore, the second circuit structure includes a first varistor, a second varistor, a third varistor and a fourth varistor;

[0029] One end of the first piezoresistor is respectively connected to one end of the second piezoresistor and the first input end of the sound pressure transmitting module, and the other end of the first piezoresistor is respectively connected to one end of the third piezoresistor and the first output end of the sound wave receiving module;

[0030] The other end of the second piezoresistor is respectively connected to one end of the fourth piezoresistor and the second output end of the sound wave receiving module, and the other end of the fourth piezoresistor is respectively connected to the other end of the third piezoresistor and the second input end of the sound wave transmitting module.

[0031] In this solution, the second circuit structure adopts a full-bridge piezoresistive structure, which is simple and reliable to implement.

[0032] The present invention also provides a method for manufacturing a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery. The method is used to manufacture the wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery as described above, and the method comprises:

[0033] A sound wave receiving module for converting sound to electricity signals is manufactured using the first piezoelectric film based on MEMS technology;

[0034] Based on the MEMS technology, a sensing structure for sensing the working state of the single cell is arranged on the second piezoelectric film to obtain a working state sensitive module;

[0035] Based on the MEMS technology, a sound wave transmitting module for electroacoustic signal conversion is manufactured using a third piezoelectric film, so that the sound wave receiving module, the working condition sensitive module and the sound wave transmitting module are sequentially arranged and connected and then embedded in the single battery cell.

[0036] The present application realizes the input of wireless energy and the real-time output of the in-situ working condition, which is beneficial for real-time monitoring of the status of the single cells of the lithium battery and is beneficial for practical production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic structural diagram of a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided by the present invention;

[0038] FIG2 is a schematic structural diagram of another wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided by the present invention;

[0039] FIG3 is a schematic structural diagram of a pressure-sensitive sensing module provided by the present invention;

[0040] FIG4 is an equivalent circuit diagram of a full-bridge piezoresistive structure provided by the present invention;

[0041] FIG5 is a schematic diagram of a first acoustic wave signal provided by the present invention;

[0042] FIG6 is a schematic diagram of a second electrical signal provided by the present invention;

[0043] FIG7 is a schematic diagram of a second acoustic wave signal provided by the present invention;

[0044] FIG8 is a schematic diagram of harmonic superposition of a square wave signal provided by the present invention;

[0045] FIG9 is a flow chart of a method for manufacturing a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided by the present invention;

[0046] Description of reference numerals:

[0047] 1-acoustic wave receiving module, 2-working condition sensitive module, 3-acoustic wave transmitting module, 21-second piezoelectric film, R1-first piezoresistor, R2-second piezoresistor, R3-third piezoresistor, R4-fourth piezoresistor, 11-structural subunit in the acoustic wave receiving module, 111-first piezoelectric film in the structural subunit in the acoustic wave receiving module, 31-structural subunit in the acoustic wave transmitting module. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0049] Please refer to FIG. 1 , which is a structural diagram of a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided by the present invention.

[0050] The present invention provides an embodiment of a wireless microsystem for real-time monitoring of in-situ pressure and temperature inside a lithium battery, which is applied to the interior of a single battery cell. The wireless microsystem for real-time monitoring of in-situ pressure and temperature inside a lithium battery includes an acoustic wave receiving module 1, a working condition sensitive module 2, and an acoustic wave transmitting module 3 manufactured based on MEMS technology;

[0051] The sound wave receiving module 1, the working condition sensitive module 2 and the sound wave transmitting module 3 are connected in sequence;

[0052] The sound wave receiving module 1 is used to convert the first sound wave signal received by the external sound wave transmitter and corresponding to the first preset resonant frequency into an acoustic-electrical signal to obtain a first electrical signal;

[0053] The operating condition sensitive module 2 is used to couple the in-situ operating condition inside the single cell to the first electrical signal to obtain a second electrical signal;

[0054] The acoustic wave transmitting module 3 is used to convert the electrical signal component in the second electrical signal that meets the second preset resonant frequency into an electroacoustic signal to emit a second acoustic wave signal, so that the external acoustic wave receiver can determine the in-situ working condition based on the received second acoustic wave signal, wherein the first preset resonant frequency is different from the second preset resonant frequency.

[0055] In this embodiment, considering that the lithium battery is a good conductor of electricity and its shell is made of metal material, the traditional electromagnetic induction wireless coupling energy method is no longer applicable. Therefore, there is an urgent need for a wireless sensing microsystem that can monitor the working condition of the lithium battery in situ online, so as to provide a key technical foundation for building an intelligent battery that can self-sense the working condition of the battery. Therefore, the present application provides a wireless microsystem for real-time monitoring of the pressure and temperature inside the lithium battery in situ, which includes an acoustic wave receiving module 1, a working condition sensitive module 2 and an acoustic wave transmitting module 3, which are arranged and connected in sequence and manufactured based on MEMS (Micro Electro Mechanical System) technology. MEMS technology integrates traditional semiconductor technologies such as lithography and corrosion into ultra-precision machining, and can integrate microcircuits and micromachines on the chip according to functional requirements, thereby realizing the miniaturization and batch production of the device to be processed, greatly improving the consistency performance of the device to be processed, reducing production costs, and increasing the spatial density and coverage of data detection. The acoustic wave receiving module 1, the working condition sensitive module 2 and the acoustic wave transmitting module 3 are manufactured using the MEMS technology.

[0056] Specifically, the wireless microsystem is arranged inside the single cell, and the operating condition sensitive module 2 can sense the in-situ operating condition state inside the single cell and couple it to the first electrical signal to obtain a second electrical signal. The in-situ operating condition state can be a temperature state or a pressure state; the first sound wave signal includes but is not limited to an ultrasonic square wave signal.

[0057] In summary, the present application provides a wireless microsystem for real-time monitoring of the in-situ pressure and temperature inside a lithium battery, which can be non-destructively implanted inside various lithium batteries, and thus effectively sense the in-situ working condition inside the single cell; the difference between the first preset resonant frequency and the second preset resonant frequency ensures that the acoustic wave transmitting module 3 is not interfered with by the first acoustic wave signal and is more conducive to the subsequent determination of the in-situ working condition, realizing the input of wireless energy and the real-time output of the in-situ working condition, which is conducive to real-time monitoring of the status of the single cell of the lithium battery and is conducive to practical production applications.

[0058] As a preferred embodiment, the sound wave receiving module 1 is a sound wave transducer, which includes a structural subunit 11, and the structural subunit 11 includes an upper electrode layer, a first piezoelectric film 111 and a lower electrode layer arranged in sequence from top to bottom;

[0059] The second preset resonant frequency is determined according to the geometric dimensions of the first piezoelectric film 111 and the thickness of the structural subunit 11 , so that the second preset resonant frequency is different from the first preset resonant frequency.

[0060] In this embodiment, the second preset resonant frequency is determined by adjusting the geometric dimensions of the first piezoelectric film 111 and the thickness of the structural subunit 11 to simulate. The second preset resonant frequency specifically corresponds to the first-order vibration mode resonant frequency of the third piezoelectric film in the acoustic wave transmitting module 3. It can be seen that the difference between the first preset resonant frequency and the second preset resonant frequency is that the first-order vibration mode resonant frequency of the first piezoelectric film 111 in the acoustic wave receiving module 1 is different from the first-order vibration mode resonant frequency of the third piezoelectric film in the acoustic wave transmitting module 3, thereby ensuring that the acoustic wave transmitting module 3 is not interfered with by the first acoustic wave signal and is more conducive to subsequent signal separation to determine the in-situ working condition.

[0061] In addition, the sound wave receiving module 1 is essentially a sound wave transducer at the hundred-micron level, and its working principle is: when excited by the first sound wave signal, it vibrates in a bending mode, thereby generating a bending moment in the first piezoelectric film 111 and thus generating mechanical stress, which is then converted into an electric charge to obtain a first electrical signal, thereby realizing the conversion of the sound signal into an electrical signal.

[0062] It should also be noted that, referring to Figure 2, Figure 2 shows that the sound wave receiver includes 16 structural subunits. To avoid confusion in the connections, only the structural subunit 11 in the upper left corner is used as an example for explanation. It can be seen that the first piezoelectric film 111 in the structural subunit 11 is specifically circular (the dark circle part in Figure 2), and the above-mentioned geometric dimensions can specifically refer to the diameter of the circular first piezoelectric film 111.

[0063] As a preferred embodiment, the structural subunits are sequentially connected to form an N*M array structure, where N is an integer greater than 1, M is an integer greater than 1, and N*M=the total number of structural subunits.

[0064] Specifically, the array structure is connected as shown in FIG2 , which is illustrated by taking N=4 and M=4 as an example. This setting is conducive to obtaining a larger first electrical signal and improving the efficiency of acoustic-electrical signal conversion.

[0065] As a preferred embodiment, the first sound wave signal is a sound wave signal having a first-order vibration mode resonance frequency consistent with the first piezoelectric film 111 .

[0066] In this solution, the first preset resonant frequency is specifically the first-order vibration mode resonant frequency of the first piezoelectric film 111; it can be understood that the acoustic wave transmitting module 3 includes a third piezoelectric film. After determining the second preset resonant frequency, the third piezoelectric film having a first-order vibration mode resonant frequency of the second preset resonant frequency is selected and the acoustic wave transmitting module 3 is manufactured based on MEMS technology.

[0067] In addition, the acoustic wave transmitting module 3 is similar to the acoustic wave receiving module 1, and can also be composed of multiple structural subunits 31 to form a 4*4 array structure, as shown in Figure 2. The working principle of the acoustic wave transmitting module 3 is explained as follows: when the second electrical signal is applied, due to the inverse piezoelectric effect, the third piezoelectric film will vibrate, converting the third electrical signal into a second acoustic wave signal, thereby realizing the conversion of electrical signal to acoustic signal.

[0068] As a preferred embodiment, the operating condition sensitive module 2 includes a second piezoelectric film and a pressure sensitive module arranged on the second piezoelectric film 21 for sensing the in-situ pressure condition inside the single cell, and / or a heat sensitive module for sensing the in-situ temperature condition inside the single cell; and when the operating condition sensitive module 2 includes a pressure sensitive module and a heat sensitive module, the pressure sensitive module and the heat sensitive module are arranged in parallel.

[0069] In this embodiment, the above configuration can ensure that the temperature and / or pressure conditions inside the single battery cell can be sensed in a timely and effective manner, so that corresponding processing solutions can be adopted subsequently.

[0070] As a preferred embodiment, the thermal sensing module includes a first circuit structure composed of multiple thermistors whose resistance changes with the temperature inside the single cell, so that the second electrical signal changes with the temperature inside the single cell.

[0071] In this solution, considering that the thermistor has the characteristic that its resistance changes with temperature, it is used to form a first circuit structure, which reliably couples the temperature conditions inside the single cell to the first electrical signal to obtain the second electrical signal; it should also be noted that the first circuit structure includes but is not limited to the full-bridge setting structure described below, which is not particularly limited here and can be flexibly set.

[0072] As a preferred embodiment, the pressure sensing module includes a second circuit structure composed of a plurality of piezoresistors whose resistance changes with the pressure inside the single cell, so that the second electrical signal changes with the pressure inside the single cell.

[0073] In this solution, the second circuit structure composed of varistors is used to reliably couple the pressure condition inside the single cell to the first electrical signal to obtain the second electrical signal.

[0074] As a preferred embodiment, the second circuit structure includes a first varistor R1, a second varistor R2, a third varistor R3 and a fourth varistor R4;

[0075] One end of the first piezoresistor R1 is connected to one end of the second piezoresistor R2 and the first input end of the sound pressure transmitting module, and the other end of the first piezoresistor R1 is connected to one end of the third piezoresistor R3 and the first output end of the sound wave receiving module 1.

[0076] The other end of the second piezoresistor R2 is respectively connected to one end of the fourth piezoresistor R4 and the second output end of the sound wave receiving module 1 , and the other end of the fourth piezoresistor R4 is respectively connected to the other end of the third piezoresistor R3 and the second input end of the sound wave transmitting module 3 .

[0077] In this solution, a full-bridge piezoresistive structure is used as the second circuit structure. Taking the piezoresistive resistor as a long straight lightly doped piezoresistive strip as an example, the design principle of the above structure is further explained:

[0078] Please refer to Figure 3, which is a structural diagram of a pressure-sensitive module provided by the present invention. When a pressure F acts on the second piezoelectric film 21 to cause it to deform, the first piezoresistor R1 and the fourth piezoresistor R4, as long straight lightly doped piezoresistors, will also produce corresponding deformation and become longer, and the corresponding resistance value will increase by ΔR. The second piezoresistor R2 and the third piezoresistor R3, as long straight lightly doped piezoresistors, will also produce corresponding deformation and become wider. According to the theory of piezoresistive effect, since the relative deformation amount of the widening is equal to the relative deformation amount of the above-mentioned lengthening, the resistance value also increases by ΔR.

[0079] Please refer to FIG4 , which is an equivalent circuit diagram of a full-bridge piezoresistive structure provided by the present invention. Assuming that the first electrical signal corresponds to the input voltage U, the second electrical signal corresponds to the output voltage U0, the resistance of the first piezoresistor R1 is R1, the resistance of the second piezoresistor R2 is R2, the resistance of the third piezoresistor R3 is R3, and the resistance of the fourth piezoresistor R4 is R4, the following relationship can be obtained based on the circuit structure:

[0080] Ideally, the resistance value of the first varistor R1 is R1 = the resistance value of the second varistor R2 is R2 =

[0081] The resistance value R3 of the third varistor R3 = the resistance value R4 of the fourth varistor R4 = R, then when the pressure sensitive module is not under pressure, the output voltage U0 = 0; according to the piezoresistive effect, when pressure acts on the second piezoelectric film 21, the resistivity of each varistor will change and the corresponding resistance value will change. Assuming that the first varistor R1 and the fourth varistor R4 are in the positive stress area, the resistance value R1 of the first varistor R1 becomes R1+ΔR1, and the resistance value R4 of the fourth varistor R4 becomes R4+ΔR4. The second varistor R2 and the third varistor R3 are in the negative stress area, then the resistance value R2 of the second varistor R2 becomes R2-ΔR2, and the resistance value R3 of the third varistor R3 becomes R3-ΔR3. Ideally, ΔR1 = ΔR3 = ΔR2 = ΔR4 = ΔR, then under pressure, the expression of the output voltage U0 is:

[0082] It can be seen that under the full-bridge piezoresistive structure, the second electrical signal output by the pressure-sensitive module (i.e., the above-mentioned output voltage U0) is proportional to the relative change of the piezoresistance. Under the action of the pressure inside the single cell, the second piezoelectric film 21 produces strain, causing the resistance value of each piezoresistor in the full-bridge piezoresistive structure to change, and the output voltage U0 changes (and the output voltage U0 is positively correlated with the pressure received), thereby coupling the in-situ pressure state inside the single cell to the first electrical signal to obtain the second electrical signal.

[0083] As a further explanation of the above embodiment, please refer to Figure 5, which is a schematic diagram of a first sound wave signal provided by the present invention. The external sound wave transmitter sends an ultrasonic square wave signal (i.e., a first sound wave signal) that is consistent with the first-order vibration mode resonance frequency of the first piezoelectric film in the sound wave receiving module 1. The sound wave receiving module 1 converts the sound-to-electric signal to obtain a first electrical signal that is input to the working condition sensitive module 2. The working condition sensitive module 2 is the pressure sensitive module described above, and the pressure sensitive module adopts the above-mentioned full-bridge piezoresistive structure as an example for explanation. The second electrical signal output from the output end of the pressure sensitive module is positively correlated with the pressure it is subjected to. The second electrical signal is specifically a square wave voltage signal. Please refer to Figure 6, which is provided by the present invention. A schematic diagram of a second electrical signal provided by the present invention is shown. The first-order vibration mode resonant frequency of the third piezoelectric film in the acoustic wave transmitting module 3 is different from the first-order vibration mode resonant frequency of the first piezoelectric film mentioned above. The first-order vibration mode resonant frequency of the third piezoelectric film is the second preset resonant frequency. Then, the electrical signal component corresponding to the second preset resonant frequency in the square wave voltage signal at the output end of the pressure sensitive module is converted into an electroacoustic signal to emit a second acoustic wave signal, thereby realizing the selective output of harmonics. Please refer to Figure 7, which is a schematic diagram of a second acoustic wave signal provided by the present invention; the external acoustic wave receiver can determine the in-situ operating state of the single cell according to the second acoustic wave signal, thereby realizing the in-situ operating state measurement of the single cell in the lithium battery.

[0084] It should also be noted that the principle of using Fourier transform to convert the acoustic wave transmitting module 3 into an electroacoustic signal only for the electrical signal component that satisfies the second preset resonant frequency in the second electrical signal is further explained. The time domain signal of the given square wave signal f(t) and the Fourier series expansion are as follows, where the period is T, the frequency is f, and the corresponding angular frequency is E is the amplitude of the signal, n is the number of expanded terms;

[0085] Please refer to Figure 8, which is a schematic diagram of harmonic superposition of a square wave signal provided by the present invention. It can be seen that the square wave signal is obtained by superposing a series of sine and cosine harmonics of different amplitudes, thereby proving that the second electrical signal is a superposition of electrical signal components of multiple different resonant frequencies. The acoustic wave emission module 3 can only perform electroacoustic signal conversion on the electrical signal component in the second electrical signal that meets the pre-set second preset resonant frequency.

[0086] Please refer to FIG. 9 , which is a flow chart of a method for manufacturing a wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided by the present invention.

[0087] The method for manufacturing the wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery is used to manufacture the wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery as described above. The method comprises:

[0088] S11: Manufacturing an acoustic wave receiving module 1 for acoustic-electrical signal conversion using a first piezoelectric film based on MEMS technology;

[0089] S12: Deploying a sensing structure for sensing the operating state of a single cell on the second piezoelectric film based on MEMS technology to obtain an operating state sensitive module 2;

[0090] S13: Based on MEMS technology, a third piezoelectric film is used to manufacture an acoustic wave transmitting module 3 for electroacoustic signal conversion, so that the acoustic wave receiving module 1, the working condition sensitive module 2 and the acoustic wave transmitting module 3 are sequentially arranged and connected and then embedded into the single battery cell.

[0091] For an introduction to the manufacturing method of the wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery provided in the present invention, please refer to the above-mentioned embodiment of the wireless microsystem for real-time in-situ pressure and temperature monitoring inside a lithium battery, which will not be described in detail here.

[0092] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

[0093] It should also be noted that, in this specification, relational terms such as first, second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not imply any actual relationship or order between these entities or operations.

Claims

1. A wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery, characterized in that, it is applied inside a single battery cell. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside the lithium battery includes an acoustic wave receiving module (1), a working condition sensitive module (2), and an acoustic wave transmitting module (3) manufactured based on MEMS technology; the acoustic wave receiving module (1), the working condition sensitive module (2), and the acoustic wave transmitting module (3) are connected in sequence; the acoustic wave receiving module (1) is used to perform acoustic-electric signal conversion on the basis of a first acoustic wave signal received from an external acoustic wave transmitter and corresponding to a first preset resonance frequency to obtain a first electric signal; the working condition sensitive module (2) is used to couple the in-situ working condition state inside the single battery cell into the first electric signal to obtain a second electric signal; the acoustic wave transmitting module (3) is used to perform electro-acoustic signal conversion on the electric signal component in the second electric signal that satisfies a second preset resonance frequency to emit a second acoustic wave signal, so that an external acoustic wave receiver can determine the in-situ working condition state according to the received second acoustic wave signal, wherein the first preset resonance frequency is different from the second preset resonance frequency.

2. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery according to claim 1, characterized in that, the acoustic wave receiving module (1) is an acoustic wave transducer, and the acoustic wave transducer includes a structural subunit (11). The structural subunit (11) includes an upper electrode layer, a first piezoelectric thin film (111), and a lower electrode layer arranged in sequence from top to bottom; the second preset resonance frequency is determined according to the geometric size of the first piezoelectric thin film (111) and the thickness of the structural subunit (11), so that the second preset resonance frequency is different from the first preset resonance frequency.

3. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery according to claim 2, characterized in that, each of the structural subunits is connected in sequence to form an N*M array structure, where N is an integer greater than 1, M is an integer greater than 1, and N*M = the total number of the structural subunits.

4. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery according to claim 2, characterized in that, the first acoustic wave signal is an acoustic wave signal consistent with the first-order vibration mode resonance frequency of the first piezoelectric thin film (111).

5. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery according to any one of claims 1 to 4, characterized in that, the working condition sensitive module (2) includes a second piezoelectric thin film (21) and a pressure sensing module disposed on the second piezoelectric thin film (21) for sensing the in-situ pressure condition inside the single battery cell, and / or a thermal sensing module for sensing the in-situ temperature condition inside the single battery cell; and when the working condition sensitive module (2) includes the pressure sensing module and the thermal sensing module, the pressure sensing module and the thermal sensing module are arranged in parallel.

6. The wireless microsystem for real-time in-situ monitoring of pressure and temperature inside a lithium battery according to claim 5, characterized in that, The thermal sensing module includes a first circuit structure composed of a plurality of thermistors whose resistance values change with the temperature inside the single battery cell, so that the second electrical signal varies with the temperature inside the single battery cell.

7. The in-situ pressure and temperature real-time monitoring wireless microsystem inside a lithium battery according to claim 5, characterized in that the pressure sensing module includes a second circuit structure composed of a plurality of piezoresistors whose resistance values change with the pressure magnitude inside the single battery cell, so that the second electrical signal varies with the pressure magnitude inside the single battery cell.

8. The in-situ pressure and temperature real-time monitoring wireless microsystem inside a lithium battery according to claim 7, characterized in that the second circuit structure includes a first piezoresistor (R1), a second piezoresistor (R2), a third piezoresistor (R3) and a fourth piezoresistor (R4); One end of the first piezoresistor (R1) is respectively connected to one end of the second piezoresistor (R2) and the first input end of the acoustic pressure emission module, and the other end of the first piezoresistor (R1) is respectively connected to one end of the third piezoresistor (R3) and the first output end of the acoustic wave receiving module (1); The other end of the second piezoresistor (R2) is respectively connected to one end of the fourth piezoresistor (R4) and the second output end of the acoustic wave receiving module (1), and the other end of the fourth piezoresistor (R4) is respectively connected to the other end of the third piezoresistor (R3) and the second input end of the acoustic wave emission module (3) of the second input end.

9. A manufacturing method of an in-situ pressure and temperature real-time monitoring wireless microsystem inside a lithium battery, characterized in that the method is used to manufacture the in-situ pressure and temperature real-time monitoring wireless microsystem inside a lithium battery according to any one of claims 1 to 8, and the method includes: Based on MEMS technology, an acoustic wave receiving module (1) for acoustic-electric signal conversion is made of a first piezoelectric film; Based on the MEMS technology, a sensing structure for sensing the operating state of the single battery cell is arranged on a second piezoelectric film to obtain an operating condition sensitive module (2); Based on the MEMS technology, an acoustic wave emission module (3) for electro-acoustic signal conversion is made of a third piezoelectric film, so that after the acoustic wave receiving module (1), the operating condition sensitive module (2) and the acoustic wave emission module (3) are arranged and connected in sequence, they are embedded into the single battery cell.

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