A multi-sensing device built into a lithium-ion battery and its preparation process

Abstract

The present application provides a multi-sensing device built into a lithium-ion battery and its manufacturing process, which relates to the field of battery pack testing. It includes: a sensor device, a signal acquisition circuit, and an external lead. The sensor device is fixed on the signal acquisition circuit and at least includes a pressure sensor and a temperature sensor. The signal acquisition circuit includes a first mounting portion and a second mounting portion. The pressure sensor is arranged on the first mounting portion, and the temperature sensor is arranged on the second mounting portion. A plurality of external leads are provided. One ends of the plurality of external leads are respectively connected to the first mounting portion and the second mounting portion to connect to the inside of the lithium-ion battery, and the other ends extend to the outside of the signal acquisition circuit to connect to a signal collector. The built-in sensing device can at least simultaneously detect the pressure and temperature inside the lithium-ion battery, realizing direct, timely, and comprehensive monitoring of the internal state of the lithium-ion battery, and further achieving the beneficial effect of early warning of thermal runaway of the lithium-ion battery.

Description

Technical Field

[0001] This application relates to the field of battery testing. Specifically, a multi-sensing device built into a lithium-ion battery and its manufacturing process are provided. Background Art

[0002] Lithium-ion batteries have continuously achieved new breakthroughs in key battery materials and battery structures, and their comprehensive performance has been continuously improved. However, with the continuous increase in energy density, the safety issues of lithium-ion batteries have become increasingly prominent. When subjected to mechanical abuse, electrical abuse, and thermal abuse, lithium-ion batteries will experience thermal runaway, leading to accidents such as explosions. Research shows that when a lithium-ion battery undergoes thermal runaway, its internal pressure and temperature will change. Therefore, developing a multi-sensing device that can simultaneously detect pressure and temperature and be built into a lithium-ion battery can achieve early warning of lithium-ion battery thermal runaway and reduce the harm of lithium-ion battery thermal runaway to society. However, the currently reported sensing devices are mainly attached to the surface of lithium-ion batteries, and the output signals are surface temperature and output voltage / current / charge and other parameters. Restricted by the gradient effect and hysteresis effect, these sensing devices are difficult to directly and timely reflect the internal state of the battery, and thus cannot quickly and accurately judge the degree of the risk of lithium-ion battery thermal runaway.

[0003] Compared with the sensor devices attached to the surface of lithium-ion batteries, the sensing devices implanted inside them can directly monitor and reflect the internal conditions of lithium-ion batteries, which is more conducive to the early warning of lithium-ion battery thermal runaway. However, the currently reported built-in sensing devices can only monitor a single parameter in real time, such as pressure, strain, temperature, etc., and cannot comprehensively reflect the internal state of lithium-ion batteries, easily leading to missed judgments of lithium-ion battery thermal runaway.

[0004] In view of the above problems, existing equipment urgently needs to be improved. Summary of the Invention

[0005] The purpose of this application is to provide a multi-sensing device built into a lithium-ion battery and its manufacturing process. The built-in sensing device can at least simultaneously detect the pressure and temperature inside the lithium-ion battery, achieve direct, timely, and comprehensive monitoring of the internal state of the lithium-ion battery, and thus achieve the beneficial effect of early warning of lithium-ion battery thermal runaway.

[0006] In the first aspect, this application provides a multi-sensing device built into a lithium-ion battery, and the technical solution is as follows:

[0007] The built-in sensing device of the lithium-ion battery includes: a sensor device, a signal acquisition circuit, and an external lead;

[0008] The sensor device is fixed on the signal acquisition circuit and at least includes a pressure sensor and a temperature sensor. The pressure sensor is made of an elastic dielectric material, and the temperature sensor is a metal thin film;

[0009] The signal acquisition circuit includes a first mounting portion and a second mounting portion. The pressure sensor is disposed on the first mounting portion, and the temperature sensor is disposed on the second mounting portion;

[0010] A plurality of external leads are provided. One ends of the plurality of external leads are respectively connected to the first mounting portion and the second mounting portion for connecting to the inside of the lithium-ion battery, and the other ends extend outward from the signal acquisition circuit for connecting to a signal collector.

[0011] A multi-sensor device built in a lithium-ion battery provided by the present application includes a sensor device, a signal acquisition circuit, and external leads. The sensor device at least includes a pressure sensor and a temperature sensor, and can at least simultaneously detect the internal pressure and temperature of the lithium-ion battery. The pressure sensor is made of an elastic dielectric material, and the temperature sensor is a metal thin film. The elastic dielectric material is sensitive to pressure but almost insensitive to temperature, while the metal thin film is sensitive to temperature but almost insensitive to pressure. Therefore, the two can respectively realize the detection of pressure and temperature, and the detection data of the two do not interfere with each other. The signal acquisition circuit includes a first mounting portion for mounting the pressure sensor and a second mounting portion for mounting the temperature sensor. The pressure sensor and the temperature sensor are separately arranged, further ensuring that the two do not interfere with each other when detecting data. A plurality of external leads are provided. One ends of the plurality of external leads are respectively connected to the first mounting portion and the second mounting portion for connecting to the inside of the lithium-ion battery, and the other ends extend outward for connecting to a signal collector, for simultaneously transmitting the internal pressure and temperature signals of the lithium-ion battery to an external signal collector, and avoiding the interference of the electromagnetic shielding effect of the battery metal shell on the sensing signals of the external leads, realizing the efficient and stable transmission and acquisition of the sensing signals, so as to directly, timely, and comprehensively monitor and obtain the internal pressure and temperature of the lithium-ion battery, and achieve the beneficial effect of early warning of the thermal runaway of the lithium-ion battery.

[0012] Further, the multi-sensor device further includes a packaging layer covering the signal acquisition circuit and packaging the sensor device on the signal acquisition circuit and the portions where the external leads are connected to the first mounting portion and the second mounting portion.

[0013] A multi-sensor device built in a lithium-ion battery provided by the present application is also provided with a packaging layer covering the signal acquisition circuit and packaging the sensor device on the signal acquisition circuit and part of the external leads to prevent the electrolyte from corroding the sensor device and realize the long-term stable service of the sensor device inside the lithium-ion battery.

[0014] Further, a ceramic tube is sleeved on the external lead, and the ceramic tube is arranged on the part where the external lead extends outside the signal acquisition circuit.

[0015] For a multi-sensing device built into a lithium-ion battery provided by the present application, by sleeving a ceramic tube on the external lead, and the ceramic tube is sleeved on the part where the external lead extends outside the signal acquisition circuit, corrosion of the external lead by the electrolyte can be prevented, and long-term stable service of the sensor device inside the lithium-ion battery can be realized.

[0016] Further, the first mounting portion and the second mounting portion are arranged at intervals.

[0017] For a multi-sensing device built into a lithium-ion battery provided by the present application, by arranging the first mounting portion and the second mounting portion at intervals, the pressure sensor and the temperature sensor do not contact each other, further ensuring the accuracy of pressure and temperature detection inside the lithium-ion battery.

[0018] Further, a plurality of electrodes are arranged on the signal acquisition circuit, and the first mounting portion and the second mounting portion are respectively connected to one ends of different electrodes.

[0019] Further, the other ends of the electrodes are connected to the external leads.

[0020] Further, the electrodes include but are not limited to interdigital electrodes, planar electrodes, two-wire electrodes, and spiral electrodes.

[0021] Further, the elastic dielectric material is of a hollow structure, and the elastic dielectric material includes a C-shaped notch.

[0022] Further, the metal thin film is arranged in the C-shaped notch of the elastic dielectric material.

[0023] In a second aspect, a preparation process of a multi-sensing device built into a lithium-ion battery provided by the present application is applied to the multi-sensing device built into a lithium-ion battery as described in any one of the above, and includes the steps:

[0024] S1: Prepare a signal acquisition circuit on a substrate;

[0025] S2: Fix the pressure sensor and the temperature sensor on the signal acquisition circuit respectively, and fix a substrate thin film on the pressure sensor and the temperature sensor;

[0026] S3: Fix the external leads on the signal acquisition circuit, one end of the external leads is connected to the pressure sensor and the temperature sensor, and the other end extends outside the signal acquisition circuit;

[0027] S4: Pour the encapsulation coating until the substrate film adheres to the pressure sensor and the temperature sensor to encapsulate the pressure sensor and the temperature sensor.

[0028] S5: Fix the part of the external lead extending outside the signal acquisition circuit in the ceramic tube to complete the preparation of the built-in sensing device.

[0029] Beneficial effects: A multi-sensing device built into a lithium-ion battery and its manufacturing process provided by this application. The multi-sensing device includes a sensor component, a signal acquisition circuit, and an external lead. The sensor includes at least a pressure sensor and a temperature sensor, and can at least simultaneously detect the pressure and temperature inside the lithium-ion battery. Among them, the pressure sensor is an elastic dielectric material, and the temperature sensor is a metal film. The elastic dielectric material is sensitive to pressure but almost insensitive to temperature, while the metal film is sensitive to temperature but almost insensitive to pressure. Therefore, the two can respectively detect pressure and temperature, and the detection data of the two do not interfere with each other. The signal acquisition circuit includes a first installation part for installing the pressure sensor and a second installation part for installing the temperature sensor. The pressure sensor and the temperature sensor are separately arranged, further ensuring that the two do not interfere with each other when detecting data. There are multiple external leads. One ends of the multiple external leads are respectively connected to the first installation part and the second installation part to connect to the inside of the lithium-ion battery, and the other ends extend outward for connecting to a signal collector, which is used to simultaneously transmit the pressure and temperature signals inside the lithium-ion battery to an external signal collector, so as to directly, timely, and comprehensively obtain the internal data of the lithium-ion battery, and then achieve the beneficial effect of early warning of thermal runaway of the lithium-ion battery. Description of the Drawings

[0030] Figure 1 It is a structural diagram of a built-in sensing device for monitoring thermal runaway of a lithium-ion battery proposed by this application.

[0031] Figure 2 It is another structural diagram of a built-in sensing device for monitoring thermal runaway of a lithium-ion battery proposed by this application.

[0032] Figure 3 It is a structural diagram of a built-in sensing device for monitoring thermal runaway of a lithium-ion battery implanted inside the lithium-ion battery proposed by this application.

[0033] Figure 4 It is a capacitance stability data diagram of the pressure sensor implanted in the lithium-ion battery.

[0034] Figure 5 It is a current stability data diagram of the temperature sensor implanted in the lithium-ion battery.

[0035] Figure 6 It is a data graph of the capacitance change of the pressure sensor in the built-in sensing device when the lithium-ion battery is heated and cooled.

[0036] Figure 7 It is a data graph of the current change flowing through the temperature sensor in the built-in sensing device when the lithium-ion battery is heated and cooled.

[0037] Figure 8 It is a data graph of the capacitance change of the pressure sensor in the built-in sensing device when the lithium-ion battery is punctured.

[0038] Figure 9 It is a data graph of the current change flowing through the temperature sensor in the built-in sensing device when the lithium-ion battery is punctured.

[0039] Figure 10 It is a flow chart of the preparation process of the built-in sensing device.

[0040] In the figure: 1. Sensor device; 2. Signal acquisition circuit; 3. External lead; 4. Encapsulation layer; 5. Lithium-ion battery; 11. Pressure sensor; 12. Temperature sensor; 21. First mounting part; 22. Second mounting part; 23. Electrode; 31. Ceramic tube; 51. Sealing nail. Specific embodiments

[0041] Next, the technical solutions in the present application will be clearly and completely described in conjunction with the accompanying drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Usually, the components of the present application described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application to be protected, but only represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0042] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, terms such as "first" and "second" are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0043] The present application provides a multi-sensing device built in a lithium-ion battery and its preparation process. The specific implementation scheme is as follows:

[0044] Please refer to Figures 1 to 2 , in the first aspect, the multi-sensing device built in the lithium-ion battery includes: a sensor device 1, a signal acquisition circuit 2, and an external lead 3;

[0045] The sensor device 1 is fixed on the signal acquisition circuit 2, and at least includes a pressure sensor 11 and a temperature sensor 12. The pressure sensor 11 is made of an elastic dielectric material, and the temperature sensor 12 is a metal thin film;

[0046] The signal acquisition circuit 2 includes a first mounting portion 21 and a second mounting portion 22. The pressure sensor 11 is arranged on the first mounting portion 21, and the temperature sensor 12 is arranged on the second mounting portion 22;

[0047] There are multiple external leads 3. One ends of the multiple external leads 3 are respectively connected to the first mounting portion 21 and the second mounting portion 22, and the other ends extend to the outside of the signal acquisition circuit 2 for connecting to a lithium-ion battery.

[0048] Among them, the pressure sensor 11 is made of an elastic dielectric material, and the elastic dielectric material includes but is not limited to silicone rubber, styrene elastomer, ion gel, and polyurethane. Preferably, it is silicone rubber, and more preferably polydimethylsiloxane; the temperature sensor 12 is a metal thin film material, including but not limited to platinum, copper, silver, gold, and nickel. Preferably, it is platinum.

[0049] Among them, in practical applications, the sensor device 1 is fixed on the signal acquisition circuit 2, and at least includes a pressure sensor 11 and a temperature sensor 12. The pressure sensor 11 can specifically be an elastic dielectric material, and the temperature sensor 12 is a metal thin film. The elastic dielectric material is a hollow structure and is easily deformed under pressure, resulting in a decrease in its capacitance, thereby realizing the sensing of pressure. While the metal thin film is difficult to deform, and the action of pressure is difficult to change the structure of the metal thin film, so it is almost insensitive to pressure. Under the action of temperature, the resistance of the metal thin film changes, thereby realizing the sensing of temperature. And at this time, the elastic dielectric material hardly deforms, so the capacitance change brought by temperature is negligible compared with the capacitance change brought by pressure. In summary, the pressure sensing function and the temperature sensing function of the built-in sensing device for monitoring the thermal runaway of lithium-ion batteries provided in this application hardly interfere with each other.

[0050] Among them, in practical applications, the signal acquisition circuit 2 can be prepared on a substrate by including but not limited to screen printing process, inkjet printing process, and sputtering process. The pressure sensor 11 and the temperature sensor 12 are respectively fixed on the first mounting portion 21 and the second mounting portion 22 on the signal acquisition circuit 2. The first mounting portion 21 and the second mounting portion 22 are made of electrode materials, which are convenient for receiving and transmitting the signals of the pressure and temperature inside the lithium-ion battery 5. Preferably, the first mounting portion 21 and the second mounting portion 22 are separately arranged at different positions on the signal acquisition circuit 2, which can ensure that the pressure sensor 11 and the temperature sensor 12 do not contact each other and do not interfere with each other when detecting data.

[0051] Among them, in practical applications, the external lead 3 is used to conduct the pressure and temperature signals inside the lithium-ion battery 5, and avoid the interference of the electromagnetic shielding effect of the battery metal shell on the sensing signal of the external lead, so as to achieve the efficient and stable transmission and acquisition of the sensing signal. The material of the external lead 3 includes but is not limited to copper wire, silver wire, gold wire and alloy wire. Preferably, it is an alloy wire, and more preferably a copper-nickel alloy wire. A plurality of external leads 3 are provided. One ends of the plurality of external leads 3 are respectively connected to the first mounting portion 21 and the second mounting portion 22. And in some preferred embodiments, two external leads 3 are respectively connected to the first mounting portion 21 and the second mounting portion 22 to ensure the stability and integrity of signal transmission. In order to ensure that different external leads 3 do not interfere with each other, the plurality of external leads 3 are arranged in parallel, so as to ensure that the pressure and temperature signals do not interfere during transmission, and further ensure the accurate determination of signal transmission. Among them, the other ends of the external leads 3 extend to the outside of the signal acquisition circuit 2 and are connected to a signal collector outside the lithium-ion battery 5. Through the direct connection of the external leads 3, the sensing signal of the sensor device 1 can be directly transmitted from the sensor device 1 to the external leads 3, and then can be directly read by the signal collector outside the battery, realizing the efficient and stable transmission and acquisition of the sensing signal. Among them, the signal collector is an electrical signal collector.

[0052] Further, in some preferred embodiments, a packaging layer 4 is further included. The packaging layer 4 covers the signal acquisition circuit 2 and packages the sensor device 1 on the signal acquisition circuit 2 and the parts where the external leads 3 are connected to the first mounting portion 21 and the second mounting portion 22.

[0053] Among them, in practical applications, the built-in sensing device for monitoring the thermal runaway of the lithium-ion battery is also provided with a packaging layer 4. The packaging layer 4 covers the signal acquisition circuit and packages the sensor device 1 on the signal acquisition circuit and part of the external leads 3 to prevent the electrolyte from corroding the sensor device 1 and realize the long-term stable service of the sensor device 1 inside the lithium-ion battery 5.

[0054] Among them, the packaging layer 4 includes a substrate film fixed above the pressure sensor 11 and the temperature sensor 12, and a packaging coating poured on the substrate film to make the substrate film fit the pressure sensor 11 and the temperature sensor 12 more closely; the material of the substrate film includes but is not limited to polyimide, polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride and aluminum-plastic film. Preferably, it is polyimide; the material of the packaging coating includes but is not limited to polyvinylidene fluoride, styrene-butadiene rubber, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene and polypropylene. Preferably, it is polypropylene.

[0055] Further, in some preferred embodiments, a ceramic tube 31 is sleeved on the external lead 3, and the ceramic tube 31 is disposed on the portion of the external lead 3 extending outside the signal acquisition circuit 2.

[0056] Among them, in practical applications, the built-in sensing device capable of monitoring the thermal runaway of lithium-ion batteries can prevent the corrosion of the external lead by the electrolyte by sleeving the ceramic tube 31 on the external lead 3, and the ceramic tube 31 is sleeved on the portion of the external lead 3 extending outside the signal acquisition circuit, so as to realize the long-term stable service of the sensor device inside the lithium-ion battery.

[0057] Further, in some preferred embodiments, the first mounting portion 21 and the second mounting portion 22 are arranged at intervals.

[0058] Among them, in practical applications, the first mounting portion 21 and the second mounting portion 22 are arranged at intervals, so that the pressure sensor 11 and the temperature sensor 12 do not contact each other, further ensuring the accuracy of the internal pressure and temperature detection of the lithium-ion battery 5. Preferably, since the volume of the elastic dielectric material is larger than that of the metal film, in order to prevent the installed elastic dielectric material from occupying too much space outward and contacting the metal film, the distance between the first mounting portion 21 and the second mounting portion 22 can be greater than half of the length dimension of the elastic dielectric material, or the area of the first mounting portion 21 can be larger than the area of the second mounting portion 22, ensuring that the elastic dielectric material and the metal film do not contact each other, thereby ensuring the accuracy of data monitoring.

[0059] Further, in some preferred embodiments, a plurality of electrodes 23 are provided on the signal acquisition circuit 2, and the first mounting portion 21 and the second mounting portion 22 are respectively connected to one end of different electrodes 23.

[0060] Among them, in practical applications, a plurality of electrodes 23 are provided on the signal acquisition circuit 2, and one ends of the plurality of electrodes 23 are respectively connected to the first mounting portion 21 and the second mounting portion 22. Since the first mounting portion 21 and the second mounting portion 22 are made of electrode materials, when signals of pressure and temperature are generated inside the lithium-ion battery 5, the first mounting portion 21 and the second mounting portion 22 can conduct the signals to the electrodes 23.

[0061] Further, in some preferred embodiments, the other end of the electrode 23 is connected to the external lead 3.

[0062] Among them, in practical applications, the other end of the electrode 23 is connected to the external lead 3, and the electrical signal is conducted to the external signal collector through the external lead 3, avoiding direct connection between the electrode 23 and the signal collector. The strength of the electrode 23 is relatively small, and it is difficult to weld with the ceramic tube 31 when attached to the signal acquisition circuit 2. Therefore, the external lead 3 with higher strength is selected to connect the electrode 23, which is convenient for subsequent welding of the external lead 3 and the ceramic tube 31. Among them, the material of the ceramic tube 31 includes but is not limited to alumina, zirconia, yttria, and mullite. Preferably, it is preferably alumina.

[0063] Furthermore, in some preferred embodiments, the electrode 23 includes but is not limited to interdigital electrodes, planar electrodes, two-wire electrodes, and spiral electrodes.

[0064] Among them, in practical applications, the electrode 23 includes but is not limited to interdigital electrodes, planar electrodes, two-wire electrodes, and spiral electrodes. In this application, the interdigital electrode is mainly used as an example for illustration. The interdigital electrode includes but is not limited to rigid electrodes or flexible electrodes, nor is it limited to metal-based electrodes or semiconductor-based electrodes. The interdigital electrode can timely transmit the pressure and temperature signals inside the lithium-ion battery to the signal collector. Among them, in some preferred embodiments, there are two electrodes 23, and the two electrodes 23 are respectively connected to the pressure sensor 11 and the temperature sensor 12, and are respectively used to transmit pressure signals and temperature signals. The two electrodes 23 are respectively arranged on the first mounting part and the second mounting part. The elastic dielectric material is fixed on the electrode 23 located on the first mounting part 21 and is used to transmit pressure signals. The metal thin film is fixed on the electrode 23 located on the second mounting part 22 and is used to transmit temperature signals. The two electrodes 23 are arranged side by side, minimizing the occupied space on the signal acquisition circuit 2, and the two electrodes 23 do not intersect each other, which can avoid interference between the pressure signal and the temperature signal during transmission, and ensure the accuracy of the pressure signal and the temperature signal obtained by the signal collector outside the lithium-ion battery 5.

[0065] Furthermore, in some preferred embodiments, the elastic dielectric material is a hollow structure, and the elastic dielectric material includes a C-shaped notch.

[0066] Specifically, please refer to Figure 1 , the elastic dielectric material can be a porous cube, which is arranged on the electrode 23 of the first mounting part 21. When the elastic dielectric material is subjected to pressure, its capacitance decreases due to deformation, thereby realizing pressure sensing. In some preferred embodiments, the elastic dielectric material can be a hollow structure (as shown in Figure 2 ). Compared with the cube structure, the hollow structure is more likely to deform under the action of pressure and is more sensitive to pressure detection. Among them, setting the elastic dielectric material to a structure with a C-shaped notch can avoid the metal thin film and the interdigital electrode at its position, ensuring the accuracy of data transmission.

[0067] Further, in some preferred embodiments, the metal thin film is disposed in the C-shaped notch of the elastic dielectric material.

[0068] Among them, in practical applications, setting the elastic dielectric material as a hollow tubular structure will cause the elastic dielectric material to occupy a large space and contact the electrodes of the metal thin film. In addition, the space available for the lithium-ion battery 5 to be used for the built-in sensor is limited. To save space while ensuring that the elastic dielectric material does not come into contact with the electrodes of the metal thin film, the metal thin film can be disposed in the C-shaped notch of the elastic dielectric material. Specifically, the interdigital electrodes for installing the metal thin film extend outwards from the C-shaped notch of the elastic dielectric material to avoid contact with the electrodes of the metal thin film, thereby achieving a comprehensive detection of the internal pressure and temperature of the lithium-ion battery 5. Among them, in this setting method, in order to avoid contact between the interdigital electrodes for placing the elastic dielectric material and the interdigital electrodes for placing the metal thin film, the size of the comb-shaped structure of the interdigital electrodes under the elastic dielectric material can be shortened so that the interdigital electrodes under the elastic dielectric material and the interdigital electrodes under the metal thin film do not contact each other (for the specific structure, please refer to Figure 2 ), ensuring the accuracy of the transmission of the pressure signal and the temperature signal.

[0069] Please refer to Figure 10 , Second, the present application provides a preparation process for a built-in sensing device, which is applied to the built-in sensing device of the lithium-ion battery described in any one of the above, and includes the steps:

[0070] S1: Prepare the signal acquisition circuit 2 on the substrate;

[0071] S2: Fix the pressure sensor 11 and the temperature sensor 12 on the signal acquisition circuit 2 respectively, and fix the substrate thin film on the pressure sensor 11 and the temperature sensor 12;

[0072] S3: Fix the external lead 3 on the signal acquisition circuit 2. One end of the external lead 3 is connected to the pressure sensor 11 and the temperature sensor 12, and the other end extends out of the signal acquisition circuit 2;

[0073] S4: Pour the encapsulation coating until the substrate thin film fits on the pressure sensor 11 and the temperature sensor 12 to encapsulate the pressure sensor 11 and the temperature sensor 12;

[0074] S5: Fix the part of the external lead 3 extending out of the signal acquisition circuit 2 in the ceramic tube 31 to complete the preparation of the built-in sensing device.

[0075] Among them, in step S1, the signal acquisition circuit 2 can be prepared on the substrate by a deposition process, which includes but is not limited to screen printing, sputtering deposition, evaporation deposition, spray deposition, and printing deposition. Preferably, screen printing is selected.

[0076] In step S2, the substrate film is a structure that constitutes the encapsulation layer 4, and its materials include but are not limited to polyimide, polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, and aluminum plastic film. Preferably, polyimide is selected, which can resist the corrosion of the electrolyte and ensure that the pressure sensor 11 and the temperature sensor 12 are not damaged.

[0077] In step S3, one end of the external lead 3 is connected to the electrode, and the other end is externally connected to the signal collector, so as to transmit the pressure signal and temperature signal inside the lithium-ion battery to the signal collector in a timely manner, facilitating the monitoring of the internal situation of the lithium-ion battery and realizing the early warning of thermal runaway inside the lithium-ion battery.

[0078] In step S4, the encapsulation coating is a structure that constitutes the encapsulation layer 4, and its materials include but are not limited to polyvinylidene fluoride, styrene-butadiene rubber, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, and polypropylene. Preferably, polypropylene is selected; it can resist the corrosion of the electrolyte and ensure that the pressure sensor 11 and the temperature sensor 12 are not damaged.

[0079] In step S5, the external lead 3 is fixed in the ceramic tube 31, which is beneficial to the stability of the fixation of the external lead 3 and ensures its better connection with the signal collector.

[0080] Among them, in practical applications, in order to implant the built-in sensing device for monitoring the thermal runaway of the lithium-ion battery 5 into the interior of the lithium-ion battery 5, the specific implantation steps are as follows: First, an opening is made on the sealing nail 51 of the lithium-ion battery 5, and then the ceramic tube 31 with the external lead 3 attached is welded and encapsulated at the opening of the sealing nail 51, which can prevent the corrosion of the external lead by the electrolyte, realize the efficient and stable transmission and acquisition of the sensing signal, and ensure the long-term stable service of the sensor device inside the lithium-ion battery.

[0081] Such as Figure 4 is the capacitance stability data diagram of the pressure sensor in the built-in sensing device implanted into the lithium-ion battery. Figure 5 is the current stability data diagram of the current flowing through the temperature sensor.

[0082] Among them, please refer to Figure 3, in practical applications, after implanting the built-in sensing device into the lithium-ion battery, the steps for the built-in sensing device to detect the internal data of the lithium-ion battery 5 are as follows: First, heat the lithium-ion battery 5, then cool it, and use a signal collector to collect the sensing signal in real time. During the heating to cooling process of the lithium-ion battery 5, the capacitance of the elastic dielectric material and the current flowing through the metal thin film change, and the change trends are opposite. As Figure 6 , Figure 7 shown, therefore, the built-in sensing device for detecting thermal runaway of the lithium-ion battery can monitor the changes in the internal environment of the lithium-ion battery 5 in real time, and thus realize the early warning of thermal runaway of the lithium-ion battery 5.

[0083] Among them, in practical applications, after implanting the built-in sensing device into the lithium-ion battery, the steps for the built-in sensing device to detect the internal data of the lithium-ion battery 5 further include: puncturing the lithium-ion battery, and using a signal collector to collect the signal output by the built-in sensor in real time. During the process of the lithium-ion battery being stimulated by puncturing, the capacitance of the pressure sensor 11 and the current flowing through the temperature sensor 12 in the built-in sensing device can be obtained. As Figure 8 , Figure 9 shown, not only do their change trends oppose each other, but they also do not interfere with each other, which makes it easy to decouple the pressure and temperature changes inside the lithium-ion battery. Moreover, the capacitance change rate of the pressure sensor 11 is greater than the change rate of the current flowing through the temperature sensor 12, indicating that the built-in sensing device can directly, quickly, and accurately monitor the changes in the internal environment of the lithium-ion battery, and thus realize the early warning of thermal runaway of the lithium-ion battery.

[0084] In this application, the pressure sensor 11 and the temperature sensor 12 are respectively fixed on the substrate with a signal acquisition circuit 2, and a part of the external lead 3 is fixed on the signal acquisition circuit 2, reducing the interference of the electromagnetic shielding effect of the battery metal shell on the sensing signal and realizing the efficient and stable transmission of the sensing signal. The sensor device 1, the signal acquisition circuit 2, and a part of the external lead 3 are encapsulated to prevent the electrolyte from corroding the sensor device 1 and the signal acquisition circuit 2. Subsequently, another part of the external lead 3 is fixed on the ceramic tube 31 by using a welding and encapsulation technique. Finally, the sealing nail 51 of the lithium-ion battery 5 is perforated, and the ceramic tube 31 with the external lead 3 is fixed at the perforation of the sealing nail 51 again by using a welding and encapsulation technique to realize the implantation of the built-in sensing device. The built-in sensing device proposed in this application for monitoring the thermal runaway of lithium-ion batteries can directly, timely, and comprehensively monitor the internal state of the lithium-ion battery 5, and thus realize the early warning of thermal runaway of the lithium-ion battery 5, so as to ensure the safe use of the lithium-ion battery 5 and reduce the harm caused by the thermal runaway of the lithium-ion battery 5 to society.

[0085] The above are only embodiments of the present application and are not intended to limit the protection scope of the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A multi-sensing device built into a lithium-ion battery, characterized in that, Including: A sensor device (1), a signal acquisition circuit (2), and an external lead (3); The sensor device (1) is fixed on the signal acquisition circuit (2), and at least includes a pressure sensor (11) and a temperature sensor (12). The pressure sensor (11) is made of an elastic dielectric material, and the temperature sensor (12) is a metal thin film; The signal acquisition circuit (2) includes a first mounting portion (21) and a second mounting portion (22). The pressure sensor (11) is disposed on the first mounting portion (21), and the temperature sensor (12) is disposed on the second mounting portion (22); A plurality of the external leads (3) are provided. One ends of the plurality of external leads (3) are respectively connected to the first mounting portion (21) and the second mounting portion (22) for connecting to the inside of a lithium-ion battery (5), and the other ends extend to the outside of the signal acquisition circuit (2) for connecting to a signal collector; The elastic dielectric material is of a hollow structure, and the elastic dielectric material includes a C-shaped notch; the metal thin film is disposed in the C-shaped notch of the elastic dielectric material.

2. The multi-sensing device built into a lithium-ion battery according to claim 1, characterized in that It further includes a packaging layer (4). The packaging layer (4) covers the signal acquisition circuit (2) to package the sensor device (1) on the signal acquisition circuit (2) and the portions where the external leads (3) are connected to the first mounting portion (21) and the second mounting portion (22).

3. A multi-sensing device built into a lithium-ion battery according to claim 2, characterized in that, A ceramic tube (31) is sleeved on the external lead (3), and the ceramic tube (31) is disposed on the portion where the external lead (3) extends to the outside of the signal acquisition circuit (2).

4. The multi-sensing device built into a lithium-ion battery according to claim 1, characterized in that, The first mounting portion (21) and the second mounting portion (22) are spaced apart.

5. The multi-sensing device built into a lithium-ion battery according to claim 4, characterized in that, A plurality of electrodes (23) are disposed on the signal acquisition circuit (2). The first mounting portion (21) and the second mounting portion (22) are respectively connected to one ends of different electrodes (23).

6. The multi-sensing device built into the lithium-ion battery according to claim 5, characterized in that, The other ends of the electrodes (23) are connected to the external leads (3).

7. The multi-sensing device built into a lithium-ion battery according to claim 6, characterized in that, The electrodes (23) include, but are not limited to, interdigital electrodes, planar electrodes, two-wire electrodes, and spiral electrodes.

8. A preparation process of a multi-sensing device built into a lithium-ion battery, characterized in that, Applied to a multi-sensing device built in a lithium-ion battery according to any one of the above claims 1-7, it includes the steps of: S1: Fabricate a signal acquisition circuit (2) on a substrate; S2: Fix the pressure sensor (11) and the temperature sensor (12) on the signal acquisition circuit (2) respectively, and fix a substrate thin film on the pressure sensor (11) and the temperature sensor (12); S3: Fix the external leads (3) on the signal acquisition circuit (2). One end of the external lead (3) is connected to the pressure sensor (11) and the temperature sensor (12), and the other end extends to the outside of the signal acquisition circuit (2); S4: Pour a packaging coating until the substrate thin film adheres to the pressure sensor (11) and the temperature sensor (12) to package the pressure sensor (11) and the temperature sensor (12); S5: Fix the part of the external lead (3) extending outside the signal acquisition circuit (2) in a ceramic tube (31) to complete the preparation of the built-in sensing device.

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