Energy storage device probe, energy storage device and internal probing method thereof

Abstract

The application provides a kind of energy storage device detector, energy storage device and its internal detection method, wherein the energy storage device detector includes piezoelectric ceramic array arranged on the symmetrical two sides of the energy storage device to be measured, the piezoelectric ceramic array on the single side of the measured energy storage device includes more than a preset number of piezoelectric ceramics arranged in phased array, the piezoelectric ceramic array on one side of the measured energy storage device is used to emit ultrasonic waves at a specific frequency under the condition of applying voltage, and the piezoelectric ceramic array on the other side is used to receive ultrasonic waves attenuated by the measured energy storage device. The application forms a piezoelectric ceramic array that can fit different sizes of energy storage devices by designing piezoelectric ceramics in phased array, and lays the piezoelectric ceramic array on the symmetrical two sides of the energy storage device respectively, so as to realize the measurement of related parameters in the energy storage device.

Description

Technical Field

[0001] This application relates to the field of internal measurement technology for energy storage devices, and in particular to an energy storage device detector, an energy storage device, and an internal detection method thereof. Background Technology

[0002] Energy storage devices are devices that store energy through a medium or equipment and release it when needed. They are becoming increasingly important in various industries, encompassing a wide range of energy harvesting devices. A crucial aspect of energy storage devices is the ability to measure their state of charge and / or charging and / or discharging current or voltage. Current technologies primarily rely on external physical measurements to determine the internal correlation coefficients (current, voltage, and impedance) of energy storage devices. However, in practice, the performance parameters measured by internal and external measurements differ significantly. Furthermore, relying solely on external physical measurements for the electrochemical reactions, generated gases, pressures, stresses, and strains within the energy storage device introduces substantial errors and lags. Summary of the Invention

[0003] The main objective of this application is to provide an energy storage device detector capable of measuring relevant parameters inside the energy storage device in real time.

[0004] Another object of this application is to provide an energy storage device including the above-described energy storage device detector.

[0005] Another objective of this application is to provide an internal detection method for the aforementioned energy storage device.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] As a first aspect, this application relates to an energy storage device detector, which has piezoelectric ceramic arrays disposed on symmetrical sides of the energy storage device under test. The piezoelectric ceramic array on one side of the energy storage device under test is used to emit ultrasonic waves at a specific frequency under the condition of applied voltage, and the piezoelectric ceramic array on the other side is used to receive ultrasonic waves attenuated by the energy storage device under test.

[0008] The piezoelectric ceramic array located on one side of the measured energy storage device comprises a greater than preset number of piezoelectric ceramics arranged in a phased array configuration, and the length L of the piezoelectric ceramic array on each side along its array arrangement direction is... λ is the wavelength of the ultrasonic wave passing through the energy storage device, and F is the wavelength of the ultrasonic wave passing through the energy storage device min F is the minimum distance between the focal point of the energy storage device measured by the incident ultrasonic wave and the piezoelectric ceramic array emitting the ultrasonic wave. max The maximum distance between the focal point of the energy storage device measured by the ultrasonic incident and the piezoelectric ceramic array emitting the ultrasonic wave is defined as follows: the distance d between two adjacent piezoelectric ceramics in the piezoelectric ceramic array is less than 0.7λ.

[0009] Further setting: The preset number of the piezoelectric ceramic arrays located on one side of the energy storage device being tested is ten.

[0010] Further configuration: the width of each piezoelectric ceramic in each group of the piezoelectric ceramic array is e, and e < 0.5λ.

[0011] Further configuration: The spacing between two adjacent piezoelectric ceramics in each group of the piezoelectric ceramic array is g, and g = de.

[0012] Further configuration: The piezoelectric ceramic array is respectively arranged on the front and rear sides, left and right sides, or top and bottom sides of the energy storage device being tested.

[0013] Further configuration: The piezoelectric ceramic has a matching layer on the side near the energy storage device for bonding with the outer shell of the energy storage device being tested.

[0014] Further configuration: The impedance of the matching layer is matched with the acoustic impedance of the shell material of the measured energy storage device.

[0015] As a second aspect, this application relates to an energy storage device, which includes an energy storage device body and an energy storage device detector as described above. The energy storage device detector is provided with two sets of piezoelectric ceramic arrays, and the two sets of piezoelectric ceramic arrays are respectively located on two symmetrical sides of the energy storage device body. The energy storage device body applies a voltage to one of the piezoelectric ceramic arrays on one side.

[0016] As a third aspect, this application relates to an internal detection method for an energy storage device, comprising the following steps:

[0017] Two sets of piezoelectric ceramic arrays of the energy storage device detector are respectively bonded to the symmetrical sides of the energy storage device under test. The piezoelectric ceramics in each set of piezoelectric ceramic arrays are arranged according to the distance between the two sides of the energy storage device under test where the piezoelectric ceramic arrays are installed and the wavelength of the ultrasonic waves excited by the piezoelectric ceramics.

[0018] The energy storage device under test applies a voltage to one side of the piezoelectric ceramic array, causing the piezoelectric ceramic array to emit ultrasonic waves at a specific frequency, while the other side receives the ultrasonic waves that have attenuated after passing through the energy storage device body.

[0019] The changes in relevant parameters inside the energy storage device are analyzed by observing and measuring the sound velocity and attenuation characteristics of ultrasonic waves after passing through the device body.

[0020] Compared with existing technologies, the solution in this application has the following advantages:

[0021] 1. In the energy storage device detector involved in this application, by designing the piezoelectric ceramics in a phased array manner to form a piezoelectric ceramic array that can fit energy storage devices of different sizes, and by laying the piezoelectric ceramic arrays on the symmetrical sides of the energy storage device, the relevant parameters inside the energy storage device can be measured. Furthermore, the phased array method can avoid occupying too much of the overall volume of the energy storage device while still having sufficient penetration power.

[0022] 2. In the energy storage device detectors involved in this application, piezoelectric ceramics have advantages such as small size and light weight, which have little impact on the overall weight of the energy storage device. Moreover, piezoelectric ceramics can work using the piezoelectric effect principle, and the voltage excited is low, making it easier to detect minute pressure changes. They also have fast frequency response and high sensitivity, thereby enabling real-time monitoring of various parameters inside the energy storage device.

[0023] 3. In the energy storage device involved in this application, by laying the piezoelectric ceramic array of the energy storage device detector on both sides of the symmetrical sides of the energy storage device body, and by making the energy storage device detector small in size, it can not only be used as an external device to detect the energy storage device, but also be installed on the energy storage device as an internal component, and combined with data acquisition and analysis instruments to read relevant data to obtain the internal state of the energy storage device.

[0024] This allows for the real-time measurement of relevant internal parameters and external pressure changes of energy storage devices by utilizing the attenuation characteristics of ultrasound. It is highly efficient, practical, small in size, and lightweight.

[0025] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0026] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the energy storage device body in one embodiment of the energy storage device of this application;

[0028] Figure 2 This is a schematic diagram of a piezoelectric ceramic array in one embodiment of the energy storage device detector of this application;

[0029] Figure 3 This is a schematic diagram of the structure of the piezoelectric ceramic and the matching layer in one embodiment of the energy storage device detector of this application.

[0030] In the diagram, 1 is the energy storage device body; 2 is the piezoelectric ceramic; and 3 is the matching layer. Detailed Implementation

[0031] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0032] To address the issues of significant errors and hysteresis in current physical measurement methods for energy storage devices, this application provides an energy storage device detector. By directly connecting to the energy storage device, it can achieve real-time measurement of the internal correlation coefficient and external pressure changes of energy storage devices of different sizes. It is highly practical, small in size, lightweight, easy to install and dismantle, and has high applicability.

[0033] Please combine Figures 1 to 3 The energy storage device detector includes piezoelectric ceramic arrays disposed on symmetrical sides of the energy storage device under test. The piezoelectric ceramic array on one side of the energy storage device under test is used to emit ultrasonic waves at a specific frequency under the condition of applied voltage, and the piezoelectric ceramic array on the other side is used to receive ultrasonic waves after attenuation by the energy storage device under test. The specific frequency can be determined according to the magnitude of the applied voltage to the energy storage device and the piezoelectric ceramic array.

[0034] This application uses a piezoelectric ceramic array to emit ultrasonic waves, utilizing the attenuation characteristics of ultrasonic waves in different media cross sections. Specifically, as ultrasonic waves propagate through a medium, their energy gradually weakens with increasing propagation distance. Therefore, during ultrasonic testing, the propagation speed and amplitude of the ultrasonic waves passing through the energy storage device are affected by the elastic modulus and density of the energy storage device. This application receives the ultrasonic signals after they pass through the energy storage device and observes and measures the sound velocity, attenuation amplitude, resonant frequency, second harmonic, and other characteristic information. This allows for the acquisition of relevant parameters within the energy storage device, such as changes in physical parameters like hardness, internal stress, interface strength, and thickness, thereby achieving real-time monitoring of various parameters within the energy storage device.

[0035] Specifically, in this embodiment, two sets of piezoelectric ceramic arrays are arranged symmetrically on both sides of the energy storage device under test, and the two sets of piezoelectric ceramic arrays can be located on the front and rear sides, left and right sides, or top and bottom sides of the energy storage device under test, respectively. In actual installation, the specific installation position of the piezoelectric ceramic arrays can be determined by the installation position of the energy storage device.

[0036] Furthermore, a matching layer 3 for bonding the piezoelectric ceramic 2 to the energy storage device is provided on the side near the energy storage device. The impedance of the matching layer 3 matches the acoustic impedance of the outer shell material of the energy storage device. The matching layer 3 eliminates the impedance mismatch that exists when ultrasonic waves pass through the outer shell of the energy storage device, thereby improving the transmission efficiency of ultrasonic waves. At the same time, the matching layer 3 also serves to isolate the piezoelectric ceramic 2 from the energy storage device. In this embodiment, the matching layer 3 can be made of epoxy resin cured material or core-shell rubber.

[0037] The piezoelectric ceramic array of this application includes a plurality of piezoelectric ceramics 2 arranged in a phased array manner. The phased array manner includes calculating the total length L of the piezoelectric ceramic array along the arrangement direction of the piezoelectric ceramics 2, the center distance d between two adjacent piezoelectric ceramics 2, the width e of a single piezoelectric ceramic 2, and the distance g between adjacent piezoelectric ceramics 2.

[0038] Specifically, the total length L of the piezoelectric ceramic array along the arrangement direction of the piezoelectric ceramics 2 can be calculated based on the length and width of the energy storage device, i.e. Where λ is the wavelength of the ultrasonic wave in the energy storage device, and F min F is the minimum distance between the focal point of the energy storage device measured by the incident ultrasonic wave and the piezoelectric ceramic array emitting the ultrasonic wave. max The maximum distance between the focal point of the ultrasonic wave incident on the energy storage device and the piezoelectric ceramic array emitting the ultrasonic wave is defined as the distance between the focal point and the energy storage device being measured. The position of the focal point depends on the length of the energy storage device and the externally applied excitation voltage. Since the transmitting source and receiving point of this application are located on opposite sides of the energy storage device, the optimal detection effect can be obtained when the ultrasonic wave focal point falls at the transmitting source and receiving point. Therefore, in this embodiment, the focal point position of the ultrasonic wave incident on the energy storage device can be changed by adjusting the excitation voltage of the piezoelectric ceramic array, so that F min With F max The sum of the values ​​is equal to or approximately equal to the length of the energy storage device, specifically the distance between the two symmetrical sides of the piezoelectric ceramic array installed on the energy storage device. The center-to-center distance d between two adjacent piezoelectric ceramics 2 is less than 0.7λ, and L / d > 10. This means that in this embodiment, the preset number of piezoelectric ceramics in each array is 10, and the total number of piezoelectric ceramics is greater than ten. The width e of a single piezoelectric ceramic 2 is less than 0.5λ, thus the distance g between two adjacent piezoelectric ceramics 2 can be calculated as g = de, and g < 0.2λ.

[0039] Based on the above calculation formula, a piezoelectric ceramic array that fits any size energy storage device can be calculated. In this application, the piezoelectric ceramic 2 is designed in a phased array manner to form a piezoelectric ceramic array, and the two sets of piezoelectric ceramic arrays are laid flat on the symmetrical sides of the energy storage device, which can realize the measurement of relevant parameters in the energy storage device. Moreover, the phased array method can avoid occupying too much of the overall volume of the energy storage device while still having sufficient penetration power.

[0040] In a preferred embodiment, the energy storage device being tested has a length of 2m, a width of 1m, and a height of 1m. The ultrasonic waves excited by the piezoelectric ceramics 2 have a sound velocity of approximately 1500m / s in the electrolyte of the energy storage device, with a frequency of 2MHz. Therefore, the wavelength λ can be calculated to be 0.75mm. In this embodiment, the piezoelectric ceramic arrays are respectively arranged at both ends of the length of the energy storage device. That is, the length of the energy storage device being tested is 2m, and the length of each group of piezoelectric ceramic arrays on one side of the energy storage device along the arrangement direction of its piezoelectric ceramics 2 is approximately 38.3m. mm. According to the formula, the center distance d between two adjacent piezoelectric ceramics 2 is less than 0.525 mm. Therefore, in this embodiment, the center distance d between two adjacent piezoelectric ceramics 2 is 0.5 mm. The width e of a single piezoelectric ceramic 2 is less than 0.375 mm. Therefore, the width e of a single piezoelectric ceramic 2 is 0.37 mm. Thus, the distance g between two adjacent piezoelectric ceramics 2 is 0.13 mm, which meets the requirement of being less than 0.2λ. In addition, the length of a single piezoelectric ceramic 2 can be designed according to actual needs, and its maximum length shall not exceed the length of the surface where the energy storage device is tested.

[0041] Specifically, in a preferred embodiment, ultrasonic waves are emitted by a piezoelectric ceramic array on one side of the energy storage device. As they pass through the interior of the energy storage device, they are altered by the physical properties of the internal materials and are then received by a piezoelectric ceramic array on the other side. For example, this embodiment can scan and record the ultrasonic transmission waveforms at various points within the energy storage device. Within a given range, the peak-to-peak values ​​of the ultrasonic waves are displayed in different colors to form an ultrasonic transmission image. By combining ultrasonic waves with visualization imaging technology based on the differences in transmittance between different media, different colors are used to image and analyze the wetting, aging, and gas generation conditions inside the battery.

[0042] Furthermore, since ultrasound is a mechanical wave that requires a medium to propagate, when there is no electrolyte wetting between the electrode materials, ultrasound can only propagate through direct contact between particles. The irregular particles cause a large amount of reflection and refraction of the ultrasound, resulting in severe signal attenuation. However, when the electrolyte is fully wetted, the liquid environment provides a good propagation path for the ultrasound, and a significant portion of the ultrasound is not interfered with by particles, thus ensuring signal strength.

[0043] The energy storage device detector of this application utilizes piezoelectric ceramics 2 in a phased array configuration to form a piezoelectric ceramic array that fits the size of the energy storage device. This array possesses sufficient penetrating power to measure relevant parameters within the energy storage device. Furthermore, due to the advantages of small size and light weight, the piezoelectric ceramics 2 have a minimal impact on the overall weight of the energy storage device. The low voltage generated by the piezoelectric ceramics 2 also reduces the impact on the power consumption of the energy storage device. Moreover, the piezoelectric ceramics 2 operate based on the piezoelectric effect principle, exhibiting fast frequency response and high sensitivity, thereby enabling real-time monitoring of various parameters within the energy storage device.

[0044] This application also relates to an energy storage device, which includes an energy storage device body 1 and an energy storage device detector as described above. The two sets of piezoelectric ceramic arrays of the energy storage device detector can be laid flat on both sides of the symmetrical sides of the energy storage device body 1. As an internal component of the energy storage device, the energy storage device outputs voltage to the piezoelectric ceramic array of the energy storage device detector to excite ultrasonic waves, and uses the attenuation characteristics of ultrasonic waves to measure relevant internal parameters and external pressure changes of the energy storage device in real time. It is highly efficient, practical, small in size and light in weight. At the same time, the voltage energy required for piezoelectric ceramics to excite ultrasonic waves is low, which can reduce the power supply energy of the energy storage device and reduce the impact on the power consumption of the energy storage device.

[0045] Furthermore, this application provides an internal detection method for the energy storage device as described above, comprising the following steps:

[0046] First, the two sets of piezoelectric ceramic arrays of the energy storage device detector are respectively bonded to the symmetrical sides of the energy storage device under test. When installing the energy storage device detector, the piezoelectric ceramics in each set of piezoelectric ceramic arrays are arranged according to the distance between the two sides of the energy storage device under test where the piezoelectric ceramic arrays are installed and the wavelength of the ultrasonic waves excited by the piezoelectric ceramics, combined with the phased array method of the piezoelectric ceramics of this application.

[0047] Secondly, the piezoelectric ceramic array on one side of the energy storage device under test is electrically connected to the energy storage device body so that the energy storage device body applies voltage to the piezoelectric ceramic array, causing the piezoelectric ceramic array to emit ultrasonic waves at a specific frequency. The piezoelectric ceramic array on the other side is used to receive the ultrasonic waves that have been attenuated after passing through the energy storage device body. The piezoelectric ceramic array that receives the ultrasonic waves can generate a high-frequency electrical signal with the same frequency as the ultrasonic waves it receives for detection and display.

[0048] Finally, the changes in relevant parameters inside the energy storage device are analyzed by observing and measuring the sound velocity and attenuation characteristics of the ultrasound waves after passing through the energy storage device.

[0049] Specifically, when determining the speed of sound of ultrasound, a direct measurement method can be used to measure the speed of sound, the propagation time and distance of the ultrasound in the energy storage device, and the propagation speed of the ultrasound in the energy storage device can be calculated according to the definition of sound waves. The attenuation mechanism of ultrasound in materials is relatively complex, so a comprehensive attenuation is considered. Assuming the sound pressure amplitude at a distance X = 0 from the source is P0, and the sound pressure amplitude after a distance X is PX, then PX = P0·e-αx, where α is called the attenuation coefficient. It can be divided into two parts: α = αs + αa, where αs is the scattering attenuation coefficient and αa is the absorption attenuation coefficient. Therefore, the attenuation coefficient, expressed as α, is a comprehensive parameter of a material, and it generally increases with the increase of the ultrasonic frequency.

[0050] Therefore, in ultrasonic testing, the degree of reduction in acoustic energy after ultrasonic waves pass through the energy storage device can be measured. For example, the reduction in the amplitude of the echo reflected from the other side of the energy storage device using the ultrasonic pulse reflection method can be used to assess the internal morphology and energy distribution of the energy storage device. Furthermore, the ultrasonic attenuation characteristics can be combined with the sound velocity characteristics to determine the electrolyte content in the energy storage device and assess the aging quality of the electrolyte, enabling real-time analysis of internal changes and reducing the errors and hysteresis associated with relying solely on external physical measurements of internal changes.

[0051] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A detector for an energy storage device, characterized in that: It includes piezoelectric ceramic arrays located on symmetrical sides of the energy storage device under test. The piezoelectric ceramic array on one side of the energy storage device under test is used to emit ultrasonic waves at a specific frequency under the condition of applied voltage, and the piezoelectric ceramic array on the other side is used to receive ultrasonic waves after they have been attenuated by the energy storage device under test. The piezoelectric ceramic array located on one side of the measured energy storage device comprises a greater than preset number of piezoelectric ceramics arranged in a phased array configuration, and the length L of the piezoelectric ceramic array on each side along its array arrangement direction is... λ is the wavelength of the ultrasonic wave passing through the energy storage device, and F is the wavelength of the ultrasonic wave passing through the energy storage device min F is the minimum distance between the focal point of the energy storage device measured by the incident ultrasonic wave and the piezoelectric ceramic array emitting the ultrasonic wave. max The maximum distance between the focal point of the energy storage device measured by the ultrasonic incident and the piezoelectric ceramic array emitting the ultrasonic wave is defined as follows: the distance d between two adjacent piezoelectric ceramics in the piezoelectric ceramic array is less than 0.7λ.

2. The energy storage device detector according to claim 1, characterized in that, The preset number of the piezoelectric ceramic arrays located on one side of the energy storage device being tested is ten.

3. The energy storage device detector according to claim 1, characterized in that, The width of each piezoelectric ceramic in the piezoelectric ceramic array is e, and e < 0.5λ.

4. The energy storage device detector according to claim 3, characterized in that, The distance between two adjacent piezoelectric ceramics in the piezoelectric ceramic array is g, where g = de.

5. The energy storage device detector according to claim 1, characterized in that, The piezoelectric ceramic arrays are respectively arranged on the front and rear sides, left and right sides, or top and bottom sides of the energy storage device being tested.

6. The energy storage device detector according to claim 1, characterized in that: The piezoelectric ceramic has a matching layer on the side closest to the energy storage device being tested, for bonding with the outer shell of the energy storage device.

7. The energy storage device detector according to claim 6, characterized in that: The impedance of the matching layer is matched with the acoustic impedance of the shell material of the measured energy storage device.

8. An energy storage device, characterized in that: The device includes an energy storage device body and an energy storage device detector as described in any one of claims 1-7. The energy storage device detector is provided with two sets of piezoelectric ceramic arrays, and the two sets of piezoelectric ceramic arrays are respectively located on two symmetrical sides of the energy storage device body. The energy storage device body applies a voltage to one of the piezoelectric ceramic arrays.

9. An internal detection method for an energy storage device as described in claim 8, characterized in that, Includes the following steps: Two sets of piezoelectric ceramic arrays of the energy storage device detector are respectively bonded to the symmetrical sides of the energy storage device under test. The piezoelectric ceramics in each set of piezoelectric ceramic arrays are arranged according to the distance between the two sides of the energy storage device under test where the piezoelectric ceramic arrays are installed and the wavelength of the ultrasonic waves excited by the piezoelectric ceramics. The energy storage device under test applies a voltage to one side of the piezoelectric ceramic array, causing the piezoelectric ceramic array to emit ultrasonic waves at a specific frequency, while the other side receives the ultrasonic waves that have attenuated after passing through the energy storage device body. The changes in relevant parameters inside the energy storage device are analyzed by observing and measuring the sound velocity and attenuation characteristics of ultrasonic waves after passing through the device body.

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