Battery internal multi-parameter monitoring microsystem module based on system-level package and packaging method

Abstract

This invention proposes a battery internal multi-parameter monitoring microsystem module and packaging method based on system-level packaging, belonging to the field of microelectronic packaging and battery management technology. The module includes: a packaging substrate; a pressure sensing chip, a temperature sensing chip, a gas sensing chip, and a signal processing chip, respectively mounted on different positions on the same plane of the packaging substrate; the signal processing chip is electrically connected to the pressure sensing chip, the temperature sensing chip, and the gas sensing chip; an integrated molding compound encapsulates the packaging substrate, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip; wherein, at least two open cavities are formed on the integrated molding compound, and the at least two open cavities expose the pressure-sensing diaphragm of the pressure sensing chip and the sensitive area of ​​the gas sensing chip, respectively.

Description

Technical Field

[0001] This invention belongs to the field of microelectronic packaging and battery management technology, and particularly relates to a battery internal multi-parameter monitoring microsystem module and packaging method based on system-level packaging. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Lithium-ion batteries, due to their high energy density and long cycle life, have become a core power source for electric vehicles, energy storage systems, and other fields. However, lithium-ion batteries pose a risk of thermal runaway during use, which may lead to serious safety accidents such as fires and explosions. Effective management of battery safety and health status has become an urgent technical challenge to be solved.

[0004] Currently, Battery Management Systems (BMS) primarily rely on external voltage and current sensors, along with a small number of temperature sensors positioned on the battery surface or between modules, for monitoring. This monitoring method lacks direct sensing capabilities for critical internal battery parameters, such as internal pressure changes, gas composition evolution, and core region temperature. When early faults such as lithium plating, internal short circuits, or electrolyte decomposition occur within the battery, external monitoring often struggles to capture abnormal signals in a timely manner, failing to provide effective early warnings.

[0005] There are technical challenges to in-situ sensing inside the battery: it needs to work stably for a long time in an environment corrosive to electrolyte, and its volume must be <30mm³ to avoid affecting the energy density of the cell. It also needs to solve multiple contradictions such as pressure permeability, air permeability, electrical isolation, and signal extraction.

[0006] Existing technologies integrate single-function sensors, such as pressure or temperature sensors, inside batteries. However, these solutions generally suffer from the following drawbacks: First, the internal space of a battery is extremely limited, and installing multiple independent sensors individually occupies a large space and introduces too many leads, increasing sealing difficulties and potential failure points. Second, dispersed sensors make it difficult to achieve simultaneous sensing of multiple parameters at the same location, resulting in poor data correlation and affecting the accuracy of fault identification. Furthermore, the long-term reliability of sensors in the harsh environment inside the battery is difficult to guarantee, and the complex wiring and packaging structure reduces the overall reliability and cost competitiveness of the system. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a battery internal multi-parameter monitoring microsystem module and packaging method based on system-in-package, which is a multi-parameter microsystem module (Microsystem-in-Package, MiP) for real-time monitoring of the internal state of the battery, specifically a system-in-package (SiP) structure that integrates pressure, temperature and gas sensors into a single package.

[0008] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: In the first aspect, a microsystem module for monitoring multiple parameters inside a battery based on system-level packaging is disclosed, including: Packaging substrate; The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are respectively mounted on different positions on the same plane of the packaging substrate; The signal processing chip is electrically connected to the pressure sensing chip, the temperature sensing chip, and the gas sensing chip, respectively. An integrated molding compound encapsulates the packaging substrate, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip. The integrated molding compound has at least two open cavities, which respectively expose the pressure-sensing diaphragm of the pressure sensing chip and the sensitive area of ​​the gas sensing chip.

[0009] As a further technical solution, the window cavity of the pressure-sensing diaphragm exposing the pressure sensing chip is filled with a pressure-permeable medium, and the window cavity of the sensitive area of ​​the gas sensing chip is covered with a breathable and liquid-proof membrane.

[0010] As a further technical solution, the pressure-permeable medium is silicone gel, and the breathable and liquid-proof membrane is expanded polytetrafluoroethylene membrane.

[0011] As a further technical solution, the packaging substrate is a multilayer ceramic substrate with a cavity or a silicon-based adapter board.

[0012] As a further technical solution, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip are electrically connected to the packaging substrate and the chip via wire bonding and / or through-silicon vias, respectively.

[0013] Secondly, a method for encapsulating microsystem modules is disclosed, comprising the following steps: Provide packaging substrate; The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are mounted on the packaging substrate. The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are electrically connected to the packaging substrate by wire bonding. The process involves transfer molding to form an integrated molded body that encapsulates the packaging substrate, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip, and at least two open cavities are formed on the integrated molded body during the molding process. The bottom of the at least two windowed cavities is processed to expose the pressure-sensing diaphragm of the pressure sensing chip and the sensitive area of ​​the gas sensing chip.

[0014] As a further technical solution, it also includes: A pressure-permeable medium is filled into the open cavity of the pressure-sensing diaphragm that exposes the pressure sensing chip; A breathable and liquid-resistant membrane is covered over the window cavity that exposes the sensitive area of ​​the gas sensing chip.

[0015] As a further technical solution, the at least two window cavities are formed in one step by setting a protruding structure in the molding die.

[0016] As a further technical solution, the pressure-permeable medium is silicone gel, which is injected into the window cavity by dispensing and then cured.

[0017] Thirdly, a battery health management system is disclosed, including: A multi-parameter integrated microsystem module is embedded inside the battery. The data acquisition and transmission module is communicatively connected to the signal processing chip of the multi-parameter integrated microsystem module, and is used to acquire the sensing data of the pressure sensing chip, the temperature sensing chip and the gas sensing chip, and transmit the sensing data to the battery management system.

[0018] The above one or more technical solutions have the following beneficial effects: The technical solution of this invention integrates multiple sensing units and processing circuits into a single miniature package using advanced system-in-package (SiP) technology. The size can be less than 5mm x 5mm, which greatly saves space and solves the problems of large space occupation and complex wiring caused by the dispersed arrangement of multiple sensors.

[0019] The technical solution of this invention integrates multiple sensing units and processing circuits into a single miniature package, which can simultaneously and synchronously sense three key parameters: pressure, temperature, and gas. Through data fusion analysis using a signal processing ASIC chip, it can identify early faults such as lithium plating, internal short circuits, and electrolyte decomposition earlier and more accurately, thus achieving precise early warning.

[0020] The module of the technical solution of this invention is an independent black box sensor unit that can communicate with an external BMS through a standard interface such as I2C, which facilitates integration, simplifies the system design of downstream customers, and reduces costs through mass production.

[0021] The technical solution of this invention adopts integrated packaging to reduce the number of external connections and interfaces, thereby reducing the single-point failure rate; the window cavity is filled with high-performance silicone gel and cured; a hydrophobic, dustproof and breathable membrane is pasted on the window cavity of the gas sensor, so as to ensure the long-term reliability of the sensor in the high temperature, high humidity and strong corrosion environment inside the battery while allowing signal sensing, and the service life reaches the whole life cycle of the battery.

[0022] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a top view schematic diagram of an embodiment of the present invention; Figure 3 This is a schematic diagram of the chip mounting structure according to an embodiment of the present invention; In the figure, 1. Packaging substrate; 2. MEMS pressure sensor chip; 3. Temperature sensor chip; 4. MEMS gas sensor chip; 5. Signal processing ASIC chip; 6. Lead wire; 7. Integrated molding compound; 8. Windowed cavity; 9. Pressure-permeable medium; 10. Breathable and liquid-proof membrane. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0027] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0028] Example 1 See appendix Figure 1 , 2 As shown in Figure 3, this embodiment discloses a battery internal multi-parameter monitoring microsystem module based on system-level packaging, including: Packaging substrate 1; MEMS pressure sensing chip 2, temperature sensing chip 3, MEMS gas sensing chip 4 and signal processing ASIC chip 5 are respectively mounted on different positions on the same plane of the packaging substrate 1. The signal processing ASIC chip 5 is electrically connected to the MEMS pressure sensor chip 2, temperature sensor chip 3 and MEMS gas sensor chip 4 respectively. An integrated molding compound 7 encapsulates a packaging substrate 1, a MEMS pressure sensing chip 2, a temperature sensing chip 3, a MEMS gas sensing chip 4, and a signal processing ASIC chip 5. The integrated molding compound 7 has at least two open cavities 8, which expose the pressure-sensitive diaphragm of the MEMS pressure sensing chip 2 and the sensitive area of ​​the MEMS gas sensing chip 4, respectively.

[0029] See you again Figure 1 As shown, the packaging substrate of the microsystem module in this embodiment serves as the system carrier platform. It can be a multilayer ceramic substrate with a cavity as the carrier. For example, packaging substrate 1 is prepared using a low-temperature co-fired ceramic process. The packaging substrate has dimensions of 4.8mm × 4.8mm × 0.5mm and contains three layers of embedded metal interconnects. The upper surface has pads for chip mounting and wire bonding. A cavity with dimensions of 2mm × 2mm × 0.3mm is located in the center of the packaging substrate. Pads for mounting pressure sensors are located at the bottom of the cavity, resulting in a smaller and more integrated design.

[0030] In another embodiment, the packaging substrate uses a silicon-based interposer. Packaging substrate 1 uses a silicon-based interposer with dimensions of 4.8mm × 4.8mm × 0.4mm, and its thickness is reduced by 0.1mm compared to a ceramic substrate. Through-silicon vias (TSVs) are fabricated on the silicon wafer using deep reactive ion etching (DRIE). The TSVs have a diameter of 50μm and a depth of 400μm. A 1μm thick silicon dioxide insulating layer is deposited on the inner wall of the TSVs, and the TSVs are filled with copper metal to achieve vertical electrical interconnection between the front and back sides of the silicon wafer. An aluminum metal wiring layer with a thickness of 2μm is fabricated on the upper surface of the silicon-based interposer for horizontal interconnection between chips. A cavity with dimensions of 2mm × 2mm × 0.3mm is formed in the center of the silicon-based interposer using DRIE.

[0031] Through-silicon via (TSV) technology enables high-density vertical interconnects with short interconnect paths and low parasitic inductance and capacitance, making it suitable for high-frequency signal transmission. The thermal expansion coefficient of the silicon-based adapter board is close to that of the silicon-based chip, resulting in low thermal stress and high reliability. The silicon-based adapter board is 0.1 mm thinner than the ceramic substrate, which is beneficial for achieving ultra-thin packaging. The overall dimensions of the microsystem module in this embodiment are 4.8 mm × 4.8 mm × 2.4 mm, making it more suitable for applications with strict requirements on package thickness.

[0032] A multifunctional sensing unit is mounted on the packaging substrate 1. The multifunctional sensing unit is composed of heterogeneous chips, including MEMS pressure sensing chip 2, temperature sensing chip 3, and MEMS gas sensing chip 4.

[0033] More specifically, the MEMS pressure sensing chip 2 is mounted on the bottom of the substrate cavity. The chip size is 1.8mm × 1.8mm × 0.4mm, and it is mounted using conductive silver paste. The curing temperature is 150℃, and the curing time is 30 minutes. The MEMS pressure sensing chip 2 adopts the capacitive pressure sensing principle. The pressure-sensing diaphragm 21 is located on the upper surface of the chip. The diaphragm size is 1mm × 1mm, and the thickness is 20μm. The pressure-sensing diaphragm 21 faces the integrated molding compound 7. The pressure sensor has a range of 0-500kPa, a sensitivity of 0.5pF / kPa, and an operating temperature range of -40℃ to 125℃.

[0034] More specifically, the temperature sensing chip 3 is mounted on the packaging substrate 1, located on one side of the MEMS pressure sensing chip 2, and its dimensions are 1.5mm × 1.5mm × 0.3mm. The temperature sensing chip 3 uses a DS18B20 digital temperature sensor with a temperature measurement range of -55℃ to 125℃ and a measurement accuracy of ±0.5℃. It outputs a digital signal without the need for external analog-to-digital conversion. In one embodiment, the temperature sensing chip 3 can also be a PT100 resistance temperature detector (RTD).

[0035] MEMS gas sensor chip 4 is mounted on the packaging substrate 1, located on the other side of pressure sensor chip 2, with chip dimensions of 2mm × 2mm × 0.4mm. MEMS gas sensor chip 4 employs a MEMS catalytic combustion hydrogen sensor, with a detection range of 0-4% volume concentration, a response time of less than 10 seconds, and an operating temperature range of -20℃ to 50℃. The sensitive area of ​​MEMS gas sensor chip 4 is located in the center of the upper surface of the chip, with dimensions of 1mm × 1mm. The MEMS gas sensor chip is used to detect hydrogen (H2), carbon monoxide (CO), or volatile organic compounds (VOCs).

[0036] The signal processing ASIC chip 5 is mounted on the packaging substrate 1, located in front of the MEMS pressure sensing chip 2, with chip dimensions of 2.5mm × 2.5mm × 0.3mm. The signal processing ASIC chip 5 integrates a 12-bit analog-to-digital converter with a sampling rate of 1kHz, capable of simultaneously acquiring the capacitance signal from the pressure sensor and the resistance signal from the gas sensor. The signal processing ASIC chip 5 also integrates a second-order low-pass filter with a cutoff frequency of 100Hz to filter out high-frequency interference signals. The control logic of the signal processing ASIC chip 5 includes signal acquisition, digital filtering, data fusion, and communication interface functions. It can transmit data with an external battery management system via an I2C interface with a clock frequency of 400kHz and a 7-bit address of 0x48.

[0037] In one embodiment, the chips are electrically interconnected with the packaging substrate 1 via wire bonding and / or through-silicon vias (TSVs). When using wire bonding, 25μm diameter leads 6 are used, with a bonding temperature of 150°C, a bonding pressure of 50g, and a bonding time of 20ms. The signal output pad of the pressure sensor chip is connected to a signal line on the substrate via lead 6; the data output pin of the temperature sensor chip 3 is connected to the digital input pin of the ASIC chip via lead 6; and the resistance signal output pad of the gas sensor chip is connected to the analog input pin of the ASIC chip via lead 6. The I2C interface pin of the ASIC chip is connected to an external interface pad on the bottom of the substrate via lead 66.

[0038] In one embodiment, the integrated molding compound 7 is formed using epoxy molding compound via transfer molding. All the aforementioned chips and interconnect structures are encapsulated within it, forming a single, compact module. The integrated package forms window cavities at the locations of the pressure-sensing diaphragm of the pressure sensor chip and the sensitive area of ​​the gas sensor chip. Transfer molding uses standard process parameters: a molding temperature of 175°C, a molding pressure of 6 MPa, and a holding time of 90 seconds. The molding die has two raised structures, forming two window cavities 8 in a single molding process on the integrated molding compound 7. The raised points on the molding die are to expose the sensing areas of the chips on the product during packaging; the two raised points can directly expose the sensitive areas of both chips simultaneously. The first window cavity 8, located directly above the MEMS pressure sensor chip 2, measures 1.2 mm × 1.2 mm × 0.8 mm and is used to expose the pressure-sensing diaphragm 21. The second window cavity 8 is located directly above the MEMS gas sensing chip 4, and measures 1.2mm × 1.2mm × 0.8mm. It is used to expose the sensitive area of ​​the gas sensor.

[0039] After the windowed cavity 8 is formed, the bottom of the cavity is treated using a laser ablation process. A pressure-permeable medium 9 is then filled into the windowed cavity 8 of the MEMS pressure sensing chip 2. The pressure-permeable medium 9 is made of medical-grade silicone gel, which has good electrolyte resistance and biocompatibility. The silicone gel is injected into the windowed cavity 8 via dispensing, with a dispensing volume of 2 microliters, and then cured at 80°C for 2 hours. The cured silicone gel completely fills the windowed cavity 8, making close contact with the pressure-sensing diaphragm 21 to achieve pressure transmission. The silicone gel has an elastic modulus of 0.5 MPa and a Poisson's ratio of 0.48, which effectively transmits pressure changes inside the battery to the pressure-sensing diaphragm 21 while simultaneously isolating the pressure sensor from electrolyte corrosion.

[0040] A breathable and liquid-resistant membrane 10 is covered on the window cavity 8 of the gas sensing chip 4. The breathable and liquid-resistant membrane 10 is made of expanded polytetrafluoroethylene (ePTFE) membrane with a thickness of 50 μm and a pore size of 0.2 μm, possessing hydrophobic, dustproof, and breathable properties. The ePTFE membrane 10 is bonded to the upper surface of the window cavity 8 by hot pressing at a temperature of 120℃, a pressure of 0.5 MPa, and a time of 30 seconds. The microporous structure of the ePTFE membrane 10 allows gas molecules to pass freely while preventing electrolyte and dust from entering the sensitive area of ​​the gas sensor, ensuring the long-term stable operation of the gas sensor in the harsh environment inside the battery.

[0041] After packaging, the module connects to the external system via a solder ball array on the bottom of the substrate. The solder ball array uses tin-lead alloy solder balls with a diameter of 0.3 mm, a spacing of 0.5 mm, and 16 balls in total, used for power supply, signal transmission, and grounding connection.

[0042] The operation of the microsystem module in this embodiment is as follows: After the module is powered on, the ASIC chip 5 first initializes and configures each sensor. The pressure sensor begins to monitor the internal pressure of the battery in real time. When gas is generated or the electrolyte decomposes inside the battery, the pressure change is transmitted to the pressure-sensing diaphragm 21 through the silicone gel. The deformation of the pressure-sensing diaphragm 21 causes a change in capacitance. The analog-to-digital converter of the ASIC chip 5 converts the capacitance signal into a digital signal. The temperature sensor monitors the internal temperature of the battery in real time and outputs a digital temperature signal to the ASIC chip. The gas sensor monitors the hydrogen concentration inside the battery in real time. When lithium plating or electrolyte decomposition occurs inside the battery, the generated hydrogen diffuses through the ePTFE membrane to the sensitive area of ​​the gas sensor. The resistance value of the gas sensor changes, and the analog-to-digital converter of the ASIC chip 5 converts the resistance signal into a digital signal.

[0043] The ASIC chip performs digital filtering on the collected pressure, temperature, and gas signals to remove high-frequency noise and interference. The filtered signals are then fused and analyzed to extract characteristic parameters such as the pressure rise rate, temperature gradient, and gas concentration change rate. When a sudden pressure change, rapid temperature rise, or hydrogen concentration exceeding a preset threshold is detected, the ASIC chip 5 sends a warning signal to the external battery management system via the I2C interface, triggering a thermal runaway warning.

[0044] This embodiment's microsystem module integrates multiple heterogeneous chips into a single package using system-in-package (SIP) technology. The module measures 4.8mm × 4.8mm × 2.5mm, reducing space occupation by over 60% compared to distributed sensor solutions. The integrated package reduces the number of external leads from 12 in traditional solutions to 4, lowering the single-point failure rate. The windowed cavity design, combined with a functional protective layer of silicone gel and ePTFE film, ensures the sensor's long-term reliability in the high-temperature, high-humidity, and highly corrosive environment inside the battery, extending its lifespan to the entire battery lifespan. As an independent sensing unit, the module connects to the battery management system via a standard I2C interface, facilitating integration and mass production, and reducing manufacturing costs by over 30% compared to multiple independent sensors.

[0045] In another embodiment, the gas sensing chip employs a composite sensor integrating multiple gas sensing units. This composite sensor integrates a hydrogen sensing unit, a carbon monoxide sensing unit, and a volatile organic compound (VOC) sensing unit on a single chip. The hydrogen sensing unit uses a MEMS catalytic combustion sensor with a detection range of 0-4% volume concentration. The carbon monoxide sensing unit uses an electrochemical sensor with a detection range of 0-1000 ppm. The VOC sensing unit uses a metal oxide semiconductor sensor with a detection range of 0-500 ppm.

[0046] The composite gas sensor has a chip size of 2.5mm × 2.5mm × 0.4mm, with three sensing units distributed on the upper surface of the chip. The sensitive area of ​​each sensing unit is 0.8mm × 0.8mm. The size of the window cavity 8 is correspondingly increased to 1.5mm × 1.5mm × 0.8mm to fully expose the sensitive areas of the three sensing units.

[0047] The ASIC chip's analog-to-digital converter is configured in three-channel mode, capable of simultaneously acquiring signals from three gas sensing units. The ASIC chip's data fusion algorithm comprehensively determines the type of internal battery fault based on the concentration change characteristics of the three gases. A rapid increase in hydrogen concentration is identified as a lithium plating fault. An increase in carbon monoxide concentration is identified as an electrolyte decomposition fault. An increase in volatile organic compound concentration is identified as a separator or electrode material decomposition fault.

[0048] The microsystem module in this embodiment can accurately identify multiple fault modes inside the battery. Compared with a single gas sensor solution, the fault identification accuracy is improved by more than 40%, and the thermal runaway warning time is 5-10 minutes earlier.

[0049] In another embodiment, through-silicon via (TSV) flip-chip interconnect technology can be used. The pressure sensor chip, temperature sensor chip, gas sensor chip, and ASIC chip all employ a chip design with TSVs. Each chip's TSV has a diameter of 30 μm and a depth equal to the chip thickness, filled with copper. Microbumps with a diameter of 50 μm and a height of 30 μm are fabricated on the bottom surface of the chip; the microbump material is a tin-lead alloy. Pads with dimensions of 60 μm × 60 μm are fabricated on the packaging substrate 1 corresponding to the microbump positions of each chip, and the pads are plated with a nickel-gold layer with a thickness of 5 μm. Each chip is mounted on the packaging substrate 1 using a flip-chip bonding process. The flip-chip bonding temperature is 260°C, the bonding time is 3 seconds, and the bonding pressure is 20 g. After flip-chip bonding, an underfill adhesive is filled between the chip and the substrate. The underfill adhesive is epoxy resin, cured at 150°C for 1 hour, to enhance mechanical strength and improve reliability. The flip-chip interconnect technology in this embodiment has the following advantages: the interconnect path is vertical, the path length is more than 90% shorter than wire bonding, parasitic inductance and capacitance are significantly reduced, making it suitable for high-frequency signal transmission. Flip-chip interconnects eliminate the need for gold wire leads, reducing the package height by 0.5mm compared to wire bonding. Flip-chip bonding has a larger number of solder joints, stronger current carrying capacity, higher mechanical strength, and superior vibration and shock resistance compared to wire bonding.

[0050] The overall dimensions of the microsystem module in this embodiment are 4.8mm × 4.8mm × 2.0mm, making it more suitable for application scenarios with strict limitations on package height.

[0051] For pouch battery applications, an ultra-thin packaging solution is adopted. In this embodiment, the packaging substrate 1 uses a silicon-based adapter board with a thickness of 0.3mm, which is 0.1mm thinner than the silicon-based adapter board in Embodiment 2. The pressure sensor chip 2, temperature sensor chip 3, gas sensor chip 4, and ASIC chip 5 are all thinned using a thinning process. The back side of the chip is thinned to 0.2mm through mechanical grinding and chemical mechanical polishing, which is 0.1-0.2mm thinner than conventional chip thickness. Each chip is mounted on the packaging substrate 1 using flip-chip interconnect technology, eliminating the need for gold wire leads and further reducing the packaging height. The thickness of the integrated molding compound 7 is controlled at 1.2mm, which is 0.3mm thinner than in Embodiment 1. The depth of the window cavity 8 is correspondingly reduced to 0.6mm.

[0052] The overall dimensions of the microsystem module in this embodiment are 5mm × 5mm × 1.8mm, with a thickness controlled within 2mm, meeting the stringent requirements of pouch batteries for the thickness of embedded sensors. The module can be embedded in the positive and negative electrode gap or separator layer of the pouch battery to achieve in-situ monitoring of the battery's core area.

[0053] The module connects to an external battery management system via a flexible flat cable. The flexible flat cable is 5mm wide, 0.1mm thick, and 50mm long, and can be led out from the edge of the pouch battery's packaging. One end of the flexible flat cable is attached to the module's external interface pads using anisotropic conductive adhesive. The adhesive application temperature is 180℃, the application pressure is 2MPa, and the application time is 10 seconds.

[0054] The ultra-thin microsystem module of this embodiment can be embedded inside a pouch battery to monitor pressure, temperature, and gas in the core area of ​​the battery in situ. Compared with sensor solutions installed on the battery end cap or externally, the monitoring sensitivity is improved by more than 50%, and the thermal runaway warning time is 10-15 minutes earlier. The ultra-thin design of the module occupies minimal internal space of the battery and has less than 0.5% impact on the battery energy density.

[0055] System-in-Package (SiP) technology is not a single technology, but a systematic combination of substrate design, heterogeneous integration, 3D interconnection, integrated molding, windowing, and functional protection layers. Through this combination, it achieves: high integration (four heterogeneous chips integrated into a single package, size <5mm×5mm); 3D interconnection (wire bonding and TSV technology achieve high-density, high-reliability interconnection); one-time molding (molded protrusion structure for one-time windowed cavity molding, avoiding damage from secondary processing); differentiated protection (silicone gel and breathable membranes are used to protect different sensor characteristics); and platform design (communication with external BMS via standard interfaces (such as I2C) for easy integration). It also achieves high-density integration of MEMS pressure sensing chips, temperature sensing chips, MEMS gas sensing chips, and signal processing ASIC chips into a single micro-package (size less than 5mm×5mm), enabling in-situ, synchronous, and fused sensing of multiple parameters within the battery.

[0056] It should be noted that although System-in-Package (SiP) technology has been widely used in consumer electronics, communication modules, and other fields, existing SiP solutions mostly employ fully sealed structures, which cannot meet the sensing requirements for environmental parameters such as pressure and gas. While some literature has proposed reserving openings in MEMS packages, these are limited to ambient temperature and pressure, non-corrosive environments, and do not address the collaborative integration of multiple heterogeneous sensors. Currently, there are no publicly available solutions for applying SiP technology to extreme conditions inside batteries, such as electrolytes, high pressure, and high temperature, and achieving a balance between sensing and protection through functionalized window designs.

[0057] Open window cavity: refers to a recessed structure formed on an integrated plastic encapsulation through molding or post-processing, used to expose the sensitive area of ​​a sensor.

[0058] In the transfer molding step, the upper mold of the molding die is provided with a protrusion structure corresponding to the window cavity. The gap between the protrusion end face and the surface of the packaging substrate is controlled at 0.2-0.5mm, so as to directly form the window cavity during the molding process and avoid the risk of chip damage caused by subsequent mechanical window opening.

[0059] The windowing process uses a 1064nm nanosecond pulsed laser with a scanning rate of 500-1000mm / s and a single ablation depth of 10-30μm. The residual molding compound at the bottom of the cavity is removed layer by layer through multiple scans until the sensitive area of ​​the sensor is exposed, with an exposure accuracy of ±50μm.

[0060] In the silicone gel filling process, the inner wall of the window is first activated by plasma cleaning (oxygen atmosphere, power 200W, 30 seconds), and then silicone gel is injected by micro-dispensing (5-10μL of gel) and cured at 80℃ for 2 hours to ensure that the adhesion strength between the silicone gel and the inner wall of the cavity is >1MPa.

[0061] In this embodiment, the depth of the pressure sensor window cavity is preferably 0.5 mm, and the diameter is 2 mm, just enough to expose the pressure-sensing diaphragm of the MEMS pressure chip. The thickness of the filling medical-grade silicone gel is controlled between 0.3 and 0.5 mm to ensure both pressure transmission efficiency and sufficient electrical isolation. The gas sensor window size is 3×3 mm, and the covering ePTFE membrane effectively blocks electrolyte penetration while allowing rapid permeation of H2 and CO.

[0062] This embodiment applies SiP (System-in-Package) packaging technology to multi-parameter sensing within the battery, pioneering a hardware integration approach and solving the long-standing internal state blind spot problem of BMS (Battery Management System), thus meeting the safety upgrade requirements of new energy vehicles. This solution advances the warning time by 5-8 minutes, providing ample time for the battery management system to execute protective measures such as power-off and cooling. By simultaneously monitoring the pressure rise rate (dP / dt) and changes in gas composition, such as CO concentration > 50 ppm, zero false alarms are achieved.

[0063] Example 2 The purpose of this embodiment is to provide a packaging method for a battery internal multi-parameter monitoring microsystem module based on system-level packaging, including: S1. Substrate preparation: Provide a packaging substrate with a cavity and pre-set interconnect lines; S2. Chip mounting: Using conductive or non-conductive adhesive, pressure sensor chips, temperature sensor chips, gas sensor chips and ASIC chips are precisely mounted on the designated positions on the substrate. S3. Three-dimensional interconnect: Connect each chip to the substrate pads through wire bonding process; for chips with TSV, flip-chip connection is performed through micro-bumps; S4. One-time molding: The entire structure is placed in a special mold and transferred to form an integrated molding body; the mold has a raised structure to form corresponding window cavities on the molding body; S5. Window opening process: Laser ablation or plasma etching process is used to clean the bottom of the cavity and accurately expose the pressure diaphragm and gas sensor area; S6. Functional layer coating: High-performance silicone gel is dripped into the opening of the pressure sensor and cured; a hydrophobic, dustproof and breathable membrane is pasted on the opening of the gas sensor; S7. Post-processing: Reflow soldering, electrical performance testing, airtightness testing, and marking.

[0064] The window cavity 8 is formed in one step by setting corresponding protrusions in the molding die. The pressure-permeable medium is silicone gel, which is injected and cured by dispensing.

[0065] Example 3 The purpose of this embodiment is to provide a battery health management system, including: a multi-parameter integrated microsystem module embedded inside the battery; a data acquisition and transmission module, communicatively connected to the signal processing ASIC chip of the multi-parameter integrated microsystem module, for acquiring sensing data from the MEMS pressure sensing chip, temperature sensing chip, and MEMS gas sensing chip, and transmitting the sensing data to the battery management system. It also includes a data fusion processing unit, communicatively connected to the data acquisition and transmission module, for fusing and analyzing the sensing data from the MEMS pressure sensing chip, temperature sensing chip, and MEMS gas sensing chip. Furthermore, it includes a fault early warning module, communicatively connected to the data fusion processing unit, for establishing a thermal runaway early warning model based on the fusion analysis results. The data acquisition and transmission module communicates with the signal processing ASIC chip via an I2C interface. The feature parameters extracted by the data fusion processing unit include pressure rise rate, temperature gradient, and gas concentration change rate. The fault early warning module triggers an early warning when it detects a sudden pressure change, a rapid temperature rise, or a hydrogen concentration exceeding a preset threshold.

[0066] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0067] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A battery internal multi-parameter monitoring microsystem module based on system-level packaging, characterized in that, include: Packaging substrate; The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are respectively mounted on different positions on the same plane of the packaging substrate; The signal processing chip is electrically connected to the pressure sensing chip, the temperature sensing chip, and the gas sensing chip, respectively. An integrated molding compound encapsulates the packaging substrate, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip. The integrated molding compound has at least two open cavities, which respectively expose the pressure-sensing diaphragm of the pressure sensing chip and the sensitive area of ​​the gas sensing chip.

2. The battery internal multi-parameter monitoring microsystem module based on system-level packaging as described in claim 1, characterized in that, The window cavity of the pressure-sensing diaphragm exposing the pressure sensing chip is filled with a pressure-permeable medium, and the window cavity of the sensitive area of ​​the gas sensing chip is covered with a breathable and liquid-proof membrane.

3. The battery internal multi-parameter monitoring microsystem module based on system-level packaging as described in claim 1, characterized in that, The pressure-permeable medium is silicone gel, and the breathable and liquid-proof membrane is expanded polytetrafluoroethylene membrane.

4. The battery internal multi-parameter monitoring microsystem module based on system-level packaging as described in claim 1, characterized in that, The packaging substrate is a multilayer ceramic substrate with cavities or a silicon-based adapter board.

5. The battery internal multi-parameter monitoring microsystem module based on system-level packaging as described in claim 1, characterized in that, The pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip are electrically connected to the packaging substrate and the chip via wire bonding and / or through-silicon vias, respectively.

6. A method for encapsulating a microsystem module, characterized in that, Includes the following steps: Provide packaging substrate; The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are mounted on the packaging substrate. The pressure sensing chip, temperature sensing chip, gas sensing chip, and signal processing chip are electrically connected to the packaging substrate by wire bonding. The process involves transfer molding to form an integrated molded body that encapsulates the packaging substrate, the pressure sensing chip, the temperature sensing chip, the gas sensing chip, and the signal processing chip, and at least two open cavities are formed on the integrated molded body during the molding process. The bottom of the at least two windowed cavities is processed to expose the pressure-sensing diaphragm of the pressure sensing chip and the sensitive area of ​​the gas sensing chip.

7. The microsystem module encapsulation method as described in claim 6, characterized in that, it further includes... include: A pressure-permeable medium is filled into the open cavity of the pressure-sensing diaphragm that exposes the pressure sensing chip; A breathable and liquid-resistant membrane is covered over the window cavity that exposes the sensitive area of ​​the gas sensing chip.

8. The microsystem module encapsulation method as described in claim 6, characterized in that, The at least two window cavities are formed in one step by setting a protruding structure in the molding die.

9. The microsystem module encapsulation method as described in claim 6, characterized in that, The pressure-permeable medium is silicone gel, which is injected into the window cavity by dispensing and then cured.

10. A battery health management system, characterized in that, include: The multi-parameter integrated microsystem module according to any one of claims 1-5 is embedded inside the battery; The data acquisition and transmission module is communicatively connected to the signal processing chip of the multi-parameter integrated microsystem module, and is used to acquire the sensing data of the pressure sensing chip, the temperature sensing chip and the gas sensing chip, and transmit the sensing data to the battery management system.

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