Flexible electrostatic pressure sensing array device and method of fabrication and monitoring device

Abstract

A flexible ionization pressure sensing array device, its fabrication method, and a monitoring device are disclosed. The device includes a first sensing electrode layer and a second sensing electrode layer arranged opposite each other. A plurality of basic sensing units are arrayed on the opposing surfaces of the two electrode layers and aligned one-to-one. Each basic sensing unit has an ionization sensitive layer on its surface. The first sensing electrode layer has a first wiring structure to connect the basic sensing units in series along a first direction, and the second electrode layer has a second wiring structure to connect the basic sensing units in series along a second direction. The first and second directions are perpendicular to each other, forming a cross matrix with the first and second wiring structures. When the aligned basic sensing units are compressed, the corresponding ionization sensitive layers contact each other to form an electrical connection and generate an ionization sensing signal. The cross matrix enables array-type detection of pressure. This invention enables in-situ, array-type monitoring of battery expansion force while improving the sensor's stress resistance and long-term stability.

Description

Technical Field

[0001] This invention relates to the field of pressure sensing devices, and in particular to a flexible voltage-isolated pressure sensing array device, its preparation method, and a monitoring device. Background Technology

[0002] With the rapid development of new energy electric vehicles and high-energy-density energy storage systems, battery safety and reliability have become one of the core issues of concern in the industry. Batteries typically undergo a certain degree of volume expansion during charge-discharge cycles. This uneven expansion is particularly pronounced in high-energy-density batteries and solid-state batteries using high-nickel cathodes, silicon-based anodes, and other technologies. Excessive local expansion forces can damage the internal structural integrity of the cell, potentially leading to internal micro-short circuits, lithium plating, and other safety hazards. In severe cases, it can even cause thermal runaway and other safety accidents.

[0003] Currently, there are still some limitations to the methods for monitoring battery expansion force: First, most traditional monitoring methods rely on external test bench equipment (such as external mechanical clamps and tension / compression sensors). This type of external monitoring is mostly a macroscopic overall force test, the equipment is large in size, and it is difficult to truly reflect the actual stress distribution in different areas inside the battery; Second, some existing solutions that attempt to embed thin-film sensors inside the battery mostly use simple single-sided printed electrodes or ordinary contact impedance principles. When faced with the complex Z-shaped winding structure inside the pouch battery and repeated expansion / contraction cycles, these sensors are easily affected by the misalignment shear stress between the electrodes, which may lead to breakage or signal distortion; Third, there is a corrosive electrolyte inside the battery. The encapsulation structure of existing internal sensors may fail during long-term deformation, causing the electrolyte to seep into the sensitive layer, thereby affecting the long-term service stability of the sensor. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings of existing technologies, such as insufficient accuracy in battery expansion monitoring, susceptibility to damage of internal thin-film sensors, and unstable performance. This invention proposes a flexible voltage-displacement stress sensing array device, its preparation method, and a monitoring device, which can realize in-situ, array-type monitoring of battery expansion force, while improving the stress resistance and long-term stability of the sensor.

[0005] The present invention adopts the following technical solution:

[0006] A flexible voltage-ionized pressure sensing array device includes a first sensing electrode layer and a second sensing electrode layer arranged opposite to each other. A plurality of basic sensing units are arrayed on the opposing surfaces of the first and second sensing electrode layers and are aligned one-to-one. Each basic sensing unit has a voltage-ionized sensitive layer on its surface. The first sensing electrode layer has a first wiring structure to connect the basic sensing units in series along a first direction, and the second electrode layer has a second wiring structure to connect the basic sensing units in series along a second direction. The first and second directions are perpendicular to each other, so that the first and second wiring structures together form a cross matrix. When the two aligned basic sensing units are compressed, the corresponding voltage-ionized sensitive layers contact each other to form an electrical connection and generate a voltage-ionized sensing signal. The array-type detection of pressure is achieved through the cross matrix.

[0007] The first sensing electrode layer and the second sensing electrode layer are flexible substrates, and the basic sensing unit is a microstructure protruding from the surface of the flexible substrate, and the microstructure is located at the node position of the cross matrix.

[0008] The first wiring structure includes multiple parallel linear leads, each of which is connected in series with a row of microstructures arranged along a first direction on the first sensing electrode layer, and each of the linear leads extends to the edge of the flexible substrate and forms an outward lead end.

[0009] The second wiring structure includes multiple parallel linear leads, each of which is connected in series with a row of microstructures arranged along the second direction on the second sensing electrode layer, and each of the linear leads extends to the edge of the flexible substrate and forms an outward lead end.

[0010] The flexible substrate is a polyimide substrate, and the microstructure, the first wiring structure and the second wiring structure are conductive patterns formed on the polyimide substrate by screen printing conductive silver paste and curing. The conductive pattern corresponding to the microstructure is circular or square.

[0011] It also includes an insulating spacer layer disposed between the first sensing electrode layer and the second sensing electrode layer. The insulating spacer layer has a plurality of through holes corresponding one-to-one with the basic sensing units, and the basic sensing units of the two layers are arranged relative to each other with a preset distance.

[0012] The ionization sensitive layer is made of a polymer matrix, organic ionic materials and inorganic confinement materials. The ionization sensitive layer is coated on the surface of each of the basic sensing units. When subjected to pressure, the ionization sensing signal is generated through ion migration and charge transfer.

[0013] A battery expansion force in-situ monitoring device includes a battery cell assembly and a flexible voltage ionization pressure sensing array device. The flexible voltage ionization pressure sensing array device is attached to the surface of the battery cell assembly. When the battery cell assembly expands and deforms, the basic sensing unit corresponding to the expansion deformation position is squeezed and generates a corresponding voltage ionization sensing signal. The in-situ, array-type monitoring of the battery pack expansion force is realized through the cross matrix.

[0014] The flexible voltage-disconnecting pressure sensing array is located on the surface of the negative electrode layer of the battery cell assembly; the outer periphery of the battery cell assembly and the flexible voltage-disconnecting pressure sensing array is also covered with a thin film layer.

[0015] A method for fabricating a flexible voltage-isolated pressure sensing array device includes:

[0016] Preparation of flexible substrates;

[0017] Conductive silver paste is screen-printed onto the flexible substrate and then cured to form a first sensing electrode layer and a second sensing electrode layer. The first sensing electrode layer has an array of basic sensing units and a first wiring structure extending along a first direction, with the first wiring structure connected in series with the basic sensing units arranged along the first direction. The second sensing electrode layer has an array of basic sensing units and a second wiring structure extending along a second direction, with the second wiring structure connected in series with the basic sensing units arranged along the second direction. The first direction and the second direction are perpendicular to each other, so that the first wiring structure and the second wiring structure together form a cross matrix.

[0018] An ionization sensitive layer is coated on the surface of the basic sensing unit of the first sensing electrode layer and the second sensing electrode layer, respectively;

[0019] An insulating spacer layer is placed between the first sensing electrode layer and the second sensing electrode layer, and the basic sensing units of the two electrode layers are aligned one by one. Then, the outer edges of the two electrode layers are aligned and bonded to obtain the flexible voltage-disconnected pressure sensing array device.

[0020] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. In this invention, by combining two opposing layers of sensing electrodes, an array of basic sensing units, and a cross-matrix wiring structure, electrical conduction of independent nodes can be achieved under pressure, simplifying the number of wirings and structurally realizing multi-point array in-plane stress scanning, thereby achieving high spatial resolution monitoring of battery expansion force.

[0022] 2. In this invention, a flexible substrate and surface microstructure electrode design are adopted, combined with screen printing molding process, so that the overall sensor array has good flexibility and structural stability, which can adapt to deformation scenarios such as batteries. At the same time, local stress concentration is formed under the action of small expansion force, which improves the sensitivity of the sensing response.

[0023] 3. In this invention, the alignment and bonding of the two electrodes and the spacing are maintained by a hollow insulating spacer layer, which not only ensures the alignment of the basic sensing unit, but also avoids accidental contact under non-pressure conditions. At the same time, it forms an independent sealed microenvironment that can resist the erosion of the electrolyte inside the battery and the shear stress, thereby improving the long-term working stability of the device.

[0024] 4. In this invention, an ionized sensitive layer composed of polymer, organic ionic materials and inorganic confinement materials is used. Under pressure, the double-layer capacitance effect can be achieved, resulting in a high rate of change of electrical signal and enabling highly sensitive pressure / expansion force monitoring.

[0025] 5. In this invention, the flexible voltage-isolated pressure sensing array device is integrated with the cell assembly, which can be directly attached to the cell surface to realize distributed in-situ monitoring of expansion force. It can obtain the force distribution at various locations inside the battery and form an evolution cloud map, providing direct and reliable data support for battery health status assessment, lithium plating early warning and thermal runaway risk judgment. Attached Figure Description

[0026] Figure 1 This is a diagram showing the device composition of the present invention;

[0027] Figure 2 This is a structural diagram of the first sensing electrode layer of the present invention;

[0028] Figure 3 This is a structural diagram of the second sensing electrode layer of the present invention;

[0029] Figure 4 This is a schematic diagram of the cross matrix formed by combining the first sensing electrode layer and the second sensing electrode layer of the present invention.

[0030] Figure 5 This is a structural diagram of the battery cell assembly;

[0031] Figure 6 This is an exploded view of the monitoring device of the present invention;

[0032] in:

[0033] 10. First sensing electrode layer; 11. Second sensing electrode layer; 12. Basic sensing unit; 14. First wiring structure; 15. Second wiring structure; 16. Insulating spacer layer; 16a. Through hole; 17. Lead end; 18. Silver-plated copper wire; 19. Battery cell assembly; 20. Positive electrode layer; 21. Negative electrode layer; 22. Insulating dielectric layer; 23. Thin film layer.

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0035] The present invention will be further described below through specific embodiments.

[0036] See Figures 1 to 4 A flexible voltage-isolated pressure sensing array device includes a first sensing electrode layer 10 and a second sensing electrode layer 11 arranged opposite to each other. A plurality of basic sensing units 12 are arrayed on the opposing surfaces of the first sensing electrode layer 10 and the second sensing electrode layer 11, with each basic sensing unit 12 on both layers aligned in a one-to-one correspondence. Each basic sensing unit 12 has a voltage-isolated sensitive layer (not shown in the figure) on its surface. The first sensing electrode layer 10 has a first wiring structure 14 for sequentially connecting the basic sensing units 12 along a first direction. The second sensing electrode layer 11 has a second wiring structure 15 for sequentially connecting the basic sensing units 12 along a second direction. The first and second directions are perpendicular to each other, so that the first wiring structure 14 and the second wiring structure 15 together form a cross matrix, for example, the first direction as the X-axis and the second direction as the Y-axis, forming an XY cross-scan matrix. When the aligned base sensing units 12 in the first sensing electrode layer 10 and the second sensing electrode layer 11 are squeezed, the corresponding ionization sensitive layers come into contact with each other to form an electrical connection, thereby generating an ionization sensing signal corresponding to the pressure magnitude. The array detection of pressure is realized through a cross matrix, thereby locating the pressure distribution position and magnitude.

[0037] In this embodiment, by coordinating the relative arrangement of dual electrode layers, the array arrangement of basic sensing units 12, and the cross-matrix wiring, in-situ array-type pressure detection is achieved, which can accurately reflect the pressure distribution in various locations within the monitoring area. When the device of this embodiment is applied to battery testing, the cross-matrix can perform row and column addressing of the pressure signal. After the basic sensing units 12 at different locations are pressurized, they can output corresponding signals through the wiring structure of the corresponding rows and columns. Based on the row and column wiring combination corresponding to the signal, the location where the pressure is generated can be determined, and the signal strength can reflect the pressure magnitude at the corresponding location, thereby realizing the monitoring of the pressure distribution location and value.

[0038] The first sensing electrode layer 10 and the second sensing electrode layer 11 are flexible substrates. The basic sensing unit 12 is a microstructure protruding from the surface of the flexible substrate, and the microstructure is located at the node position of the cross matrix. The node position is the position where the first wiring structure 14 and the second wiring structure 15 intersect.

[0039] The flexible substrate is a polyimide substrate, possessing good flexibility and structural stability, capable of adapting to deformation during battery expansion. The microstructure, the first wiring structure 14, and the second wiring structure 15 are conductive patterns formed on the polyimide substrate by screen printing conductive silver paste and curing, with a thickness of 0.1-0.2 mm. The conductive patterns corresponding to the microstructure are circular or square, facilitating alignment and contact with the microstructures on the opposite electrode layer.

[0040] Furthermore, the first sensing electrode layer 10 and the second sensing electrode layer 11 are mirror images of each other, so that the basic sensing units 12 on the two electrode layers are physically aligned one-to-one. The basic units on the first sensing electrode layer 10 and the second sensing electrode layer 11 are arranged in an array along the first direction and the second direction, that is, arranged in several rows and several columns.

[0041] The first wiring structure 14 includes multiple parallel linear leads. Each linear lead is connected in series with a row of microstructures arranged along the first direction on the first sensing electrode layer 10. Each linear lead extends to the edge of the flexible substrate and forms an outward lead end 17, which is used to connect an external signal acquisition module.

[0042] The second wiring structure 15 includes multiple parallel linear leads, each of which is connected in series with a row of microstructures arranged along the second direction on the second sensing electrode layer 11. Each linear lead extends to the edge of the flexible substrate and forms an outwardly extending lead end 17, which is used to connect an external signal acquisition module.

[0043] In this embodiment, a mirror symmetry and array arrangement design is adopted to ensure precise alignment of the two basic sensing units 12. The microstructures in each row and column are connected in series by parallel linear leads, and the lead ends 17 are led out to the outside of the substrate. This not only realizes cross-matrix signal addressing, but also facilitates direct signal acquisition by external circuits. The overall structure is simple and the layout is neat.

[0044] Furthermore, it also includes an insulating spacer layer 16 disposed between the first sensing electrode layer 10 and the second sensing electrode layer 11. The insulating spacer layer 16 is provided with a plurality of through holes 16a corresponding one-to-one with the basic sensing units 12, and the outer edges of the first sensing electrode layer 10 and the second sensing electrode layer 11 are aligned and bonded so that the basic sensing units 12 of the two layers are set at a preset distance relative to each other.

[0045] The shape and size of the through-hole 16a are adapted to the shape and size of the basic sensing unit 12. The thickness of the insulating spacer layer 16 is 0.1-0.2 mm; the whole is an insulating double-sided adhesive ring with several arrayed through-holes 16a. The first sensing electrode layer 10 and the second sensing electrode layer 11 are aligned and bonded through the insulating double-sided adhesive ring, and the basic sensing units 12 of the two layers can maintain a one-to-one correspondence and direct alignment within the through-hole area of ​​the insulating double-sided adhesive ring.

[0046] In this embodiment, the ionization sensitive layer is made of a composite of polymer matrix, organic ionic material and inorganic confinement material. The ionization sensitive layer is coated on the surface of each basic sensing unit 12. When subjected to pressure, it generates an ionization sensing signal through ion migration and charge transfer.

[0047] The raw material components of the ionization sensitive layer include a polymer matrix, organic ionic materials, and inorganic confinement materials. The polymer matrix is ​​thermoplastic polyurethane (TPU), the organic ionic material is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, and the inorganic confinement materials include spherical boron nitride and carbon nanotubes.

[0048] This embodiment also proposes a method for fabricating a flexible voltage-disconnected force sensing array device, including:

[0049] 1) Preparation of a flexible substrate. Specifically, a polyimide (PI) sheet with a thickness of approximately 0.1-0.2 mm is used as the flexible substrate for the first sensing electrode layer 10 and the second sensing electrode layer 11. The substrate is treated with a plasma cleaning machine to enhance the adhesion of subsequent printed layers.

[0050] 2) Conductive silver paste is screen-printed onto a flexible substrate and cured to form a first sensing electrode layer 10 and a second sensing electrode layer 11, respectively. The first sensing electrode layer 10 has an array of basic sensing units 12 and a first wiring structure 14 extending along a first direction. The first wiring structure 14 is connected in series with the basic sensing units 12 arranged along the first direction. The second sensing electrode layer 11 has an array of basic sensing units 12 and a second wiring structure 15 extending along a second direction. The second wiring structure 15 is connected in series with the basic sensing units 12 arranged along the second direction. The first direction and the second direction are perpendicular to each other, so that the first wiring structure 14 and the second wiring structure 15 together form a cross matrix.

[0051] In this step, a conductive matrix pattern is constructed on the surface of the PI substrate using a screen printing process. A microstructure area with a diameter of approximately 5 mm is printed using conductive silver paste as the basic sensing unit 12, and linear leads extend to the edge of the substrate and outward to form lead-out terminals. After heat curing, a conductive pattern with a thickness of approximately 0.1-0.2 mm is formed.

[0052] 3) Coat the surfaces of the base sensing unit 12 with ionization sensitive layers on the first sensing electrode layer 10 and the second sensing electrode layer 11, respectively. This step includes two processes: preparation of the ionization sensitive layer slurry and coating and curing.

[0053] First, the ionization-sensitive layer slurry was prepared: 2g of thermoplastic polyurethane (TPU) was dissolved in 5ml of N,N-dimethylformamide (DMF); after complete dissolution, 3.5g of nano-spherical boron nitride (s-BN) was added, stirred and ultrasonically dispersed; then 0.06g of carbon nanotubes (CNT) was added, and stirring and ultrasonication were continued until uniform dispersion was achieved; finally, 1ml of highly sensitive ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, [EMIM][TFSI]) was added, and after uniform mixing, a homogeneous and stable composite ionization-sensitive slurry was formed.

[0054] Next, the ionization sensitive layer is coated: using screen printing technology, the prepared composite paste is evenly printed on the surface of the base sensing unit 12 of the first sensing electrode layer 10 and the second sensing electrode layer 11, and after curing, a complete ionization sensitive layer is formed.

[0055] This step also includes lead-out treatment: silver-plated copper wire 18 is glued to the end of the lead-out and mechanically reinforced and insulated.

[0056] 4) An insulating spacer layer 16 is disposed between the first sensing electrode layer 10 and the second sensing electrode layer 11, and the basic sensing units 12 of the two electrode layers are aligned with the through holes 16a one by one. Then, the outer edges of the two electrode layers are aligned and bonded to obtain a flexible voltage-disconnected pressure sensing array device.

[0057] In this step, an insulating double-sided adhesive ring with a thickness of approximately 0.1-0.2 mm and several through holes 16a is used as the insulating spacer layer 16. The first sensing electrode layer 10 and the second sensing electrode layer 11 are aligned and bonded through this double-sided adhesive ring, ensuring that the basic sensing unit 12 areas in the two layers are aligned one-to-one, and that their respective lead ends 17 are led out. Finally, an insulating dielectric layer 22 can be wrapped around the periphery for overall independent sealing to prevent electrolyte corrosion.

[0058] See Figure 6 This embodiment also proposes an in-situ battery expansion force monitoring device, including a battery cell assembly 19 and the aforementioned flexible voltage-displacement pressure sensing array device. The flexible voltage-displacement pressure sensing array device is attached to one side surface of the battery cell assembly 19, adapting to the shape of that side surface to ensure that the expansion deformation of the battery cell assembly 19 can be captured. When the battery cell assembly 19 expands and deforms, the basic sensing unit 12 corresponding to the expansion deformation position is compressed and generates a voltage-displacement sensing signal corresponding to the magnitude of the expansion force. In-situ, array-type monitoring of the battery pack expansion force is achieved through a cross matrix, which can reflect the expansion force distribution in each region of the battery cell assembly 19.

[0059] Among them, see Figure 5 The battery cell assembly 19 includes a positive electrode layer 20, a negative electrode layer 21, and an insulating dielectric layer 22. The insulating dielectric layer 22 is Z-shaped and covers both surfaces of the positive electrode layer 20 and both surfaces of the negative electrode layer 21, serving to isolate the positive electrode layer 20 from the negative electrode layer 21 and prevent short circuits. The flexible voltage-isolated pressure sensing array is located outside the insulating dielectric layer 22 on the side of the negative electrode layer 21 facing away from the positive electrode layer 20. Simultaneously, the battery cell assembly 19 and the flexible voltage-isolated pressure sensing array are also covered by a thin film layer 23, which is made of aluminum-plastic film, and the thin film layer 23 is separated from the battery cell assembly 19 by the insulating dielectric layer 22. This structure not only seals and protects the battery cell assembly 19 and the flexible voltage-isolated pressure sensing array, preventing external environmental factors from affecting their operational stability, but also fixes the contact position of the flexible voltage-isolated pressure sensing array, ensuring that the sensing array and the battery cell assembly 19 deform synchronously during monitoring, further improving the accuracy and reliability of expansion force monitoring.

[0060] During monitoring, the external testing equipment is connected to the linear leads of the first wiring structure 14 and the second wiring structure 15 of the flexible voltage-isolated pressure sensing array. During the entire battery cycle charging and discharging process, the electrical signal changes of the basic sensing unit 12 of each node in the cross matrix are collected in real time through polling scanning. Combined with the row and column addressing function of the cross matrix, the position of the basic sensing unit 12 corresponding to each electrical signal is matched to ensure that the signal corresponds one-to-one with the expansion position of the cell group 19.

[0061] Based on the changes in electrical signals of each basic sensing unit 12, and combined with the preset relationship between signal and pressure curves, the real-time volume expansion force distribution, expansion force magnitude, and evolution data over time at different locations on the surface of the battery cell assembly 19 are calculated and obtained, clearly presenting the differences and trends in expansion force in different regions of the battery cell assembly 19.

[0062] Based on the volume expansion force distribution and evolution data obtained above, the changes in the internal structure of the cell pack 19 can be further analyzed, thereby scientifically assessing the health status of the battery. At the same time, abnormal expansion signals can be captured in a timely manner. When the expansion force in a certain area exceeds the preset safety threshold, early warning of potential battery safety hazards can be achieved, thereby enabling early assessment of battery health status (SOH), lithium plating risk, and thermal runaway risk, providing reliable data support and guarantee for the safe and stable operation of the battery.

[0063] In this invention, the terms "first," "second," and "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. The use of terms such as "upper," "lower," "left," "right," "front," and "rear" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention, not to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the scope of protection of this invention. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0064] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0065] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A flexible, electrically isolated, pressure sensing array device, characterized by, The device includes a first sensing electrode layer and a second sensing electrode layer arranged opposite to each other. The opposing surfaces of the first and second sensing electrode layers are respectively arrayed with a plurality of basic sensing units, which are aligned one-to-one. Each basic sensing unit has an ionization sensitive layer on its surface. The first sensing electrode layer has a first wiring structure to connect the basic sensing units in series along a first direction, and the second sensing electrode layer has a second wiring structure to connect the basic sensing units in series along a second direction. The first and second directions are perpendicular to each other, so that the first and second wiring structures together form a cross matrix. When the two aligned basic sensing units are compressed, the corresponding ionization sensitive layers come into contact with each other to form an electrical connection and generate an ionization sensing signal. The array-type detection of pressure is achieved through the cross matrix.

2. The flexible voltage-disconnected force sensing array device as described in claim 1, characterized in that, The first sensing electrode layer and the second sensing electrode layer are flexible substrates, and the basic sensing unit is a microstructure protruding from the surface of the flexible substrate, and the microstructure is located at the node position of the cross matrix.

3. The flexible voltage-isolated pressure sensing array device as described in claim 2, characterized in that, The first wiring structure includes multiple parallel linear leads, each of which is connected in series with a row of microstructures arranged along a first direction on the first sensing electrode layer, and each of the linear leads extends to the edge of the flexible substrate and forms an outward lead end.

4. The flexible voltage-isolated pressure sensing array device as described in claim 2, characterized in that, The second wiring structure includes multiple parallel linear leads, each of which is connected in series with a row of microstructures arranged along the second direction on the second sensing electrode layer, and each of the linear leads extends to the edge of the flexible substrate and forms an outward lead end.

5. The flexible voltage-disconnected force sensing array device as described in claim 2, characterized in that, The flexible substrate is a polyimide substrate, and the microstructure, the first wiring structure and the second wiring structure are conductive patterns formed on the polyimide substrate by screen printing conductive silver paste and curing. The conductive pattern corresponding to the microstructure is circular or square.

6. The flexible voltage-disconnected force sensing array device as described in claim 1, characterized in that, It also includes an insulating spacer layer disposed between the first sensing electrode layer and the second sensing electrode layer. The insulating spacer layer has a plurality of through holes corresponding one-to-one with the basic sensing units, and the basic sensing units of the two layers are arranged relative to each other with a preset distance.

7. The flexible voltage-disconnected force sensing array device as described in claim 1, characterized in that, The ionization sensitive layer is made of a polymer matrix, organic ionic materials and inorganic confinement materials. The ionization sensitive layer is coated on the surface of each of the basic sensing units. When subjected to pressure, the ionization sensing signal is generated through ion migration and charge transfer.

8. A battery expansion force in-situ monitoring device, comprising a battery cell assembly, characterized in that, It also includes a flexible voltage-displacement pressure sensing array device according to any one of claims 1 to 7, wherein the flexible voltage-displacement pressure sensing array device is attached to the surface of the battery cell assembly, and when the battery cell assembly expands and deforms, the basic sensing unit corresponding to the expansion deformation position is squeezed and generates a corresponding voltage-displacement sensing signal, thereby realizing in-situ, array-type monitoring of the battery pack expansion force through the cross matrix.

9. The battery expansion force in-situ monitoring device as described in claim 8, characterized in that, The flexible voltage-disconnecting pressure sensing array is located on the surface of the negative electrode layer of the battery cell assembly; the outer periphery of the battery cell assembly and the flexible voltage-disconnecting pressure sensing array is also covered with a thin film layer.

10. A method for fabricating a flexible voltage-isolated pressure sensing array device, characterized in that, include: Preparation of flexible substrates; Conductive silver paste is screen-printed onto the flexible substrate and then cured to form a first sensing electrode layer and a second sensing electrode layer, respectively. The first sensing electrode layer has an array of basic sensing units and a first wiring structure extending along a first direction, wherein the first wiring structure is connected in series with the basic sensing units arranged along the first direction. The second sensing electrode layer has an array of basic sensing units and a second wiring structure extending along a second direction, wherein the second wiring structure is connected in series with the basic sensing units arranged along the second direction. The first direction and the second direction are perpendicular to each other, so that the first wiring structure and the second wiring structure together form a cross matrix; An ionization sensitive layer is coated on the surface of the basic sensing unit of the first sensing electrode layer and the second sensing electrode layer, respectively; An insulating spacer layer is placed between the first sensing electrode layer and the second sensing electrode layer, and the basic sensing units of the two electrode layers are aligned one by one. Then, the outer edges of the two electrode layers are aligned and bonded to obtain the flexible voltage-disconnected pressure sensing array device.

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