Integrated state monitoring function of a battery

Abstract

The invention relates to a battery (1) comprising a battery component (2), a sensor (3), two sensor electrodes (4), and an electrical line (5), wherein the sensor (3) is integrated into the battery component (2) as a microstructure, the two sensor electrodes (4) are integrated into the battery component (2) in such a way that the sensor electrodes can be galvanically contacted from outside the battery components (2), and the electrical line (5) connects the sensor (3) to the sensor electrodes (4) in such a way that the sensor can be read out via the electrical line (5). In this manner, the state of a battery (1) can be efficiently monitored.

Description

[0001] Integrated battery condition monitoring

[0002] The invention relates to a battery, a method for manufacturing a battery component and a method for measuring the state properties of a battery.

[0003] Batteries are essential for storing and delivering electrical energy in a wide range of applications, from portable electronics to electric vehicles and stationary energy storage systems. However, a key challenge lies in continuously monitoring battery health to optimize performance and lifespan. Currently, no comprehensive, integrated sensor solution exists that can directly capture critical condition parameters such as temperature, internal pressure, and gas composition within the battery. This leads to a number of problems that can negatively impact battery efficiency and reliability.

[0004] A major challenge is temperature monitoring. Temperature significantly impacts battery performance and lifespan. Overheating can accelerate the aging of battery materials, while extremely low temperatures can reduce battery performance. Without accurate and direct measurements of the internal temperature, it is difficult to optimize battery operation and effectively implement thermal management strategies. External temperature sensors can only provide limited insight into the actual temperatures within the battery cells, as they cannot accurately reflect heat distribution and conduction within the battery.

[0005] Another critical issue is monitoring internal pressure. During charging and discharging, chemical reactions can occur within the battery, leading to the formation of gases. This can increase the internal pressure and potentially damage the battery's structure or even lead to dangerous situations such as a battery fire or explosion. Currently, there is no efficient way to continuously monitor the internal pressure within the battery, which limits the ability to respond to potential problems early. Monitoring the gas composition within the battery is also of great importance. Various chemical processes can lead to the formation of gases such as hydrogen, oxygen, or carbon dioxide. These gases can provide clues about the battery's condition and the chemical reactions taking place.For example, the formation of hydrogen can indicate an overload or internal short circuits, while the presence of oxygen can indicate decomposition of electrolytes or other materials. Without sensors that can monitor these gases in real time, this important information remains unused.

[0006] Microsystems engineering describes the combination and integration of micromechanical or micro-optical components with microelectronic circuits to form complex systems. A key component of microsystems engineering is microprocess engineering, which deals with physical and chemical processes in microstructured devices. Microsystems comprise sensors, actuators, and data processing units, manufactured by combining various microtechnology techniques such as micromechanics, microfluidics, bioelectronics, micro-optics, and microelectronics. The integration of components is achieved either through discrete components or monolithically in semiconductor materials such as crystalline silicon or gallium arsenide.Manufacturing techniques used include thin-film techniques, molding techniques such as LIGA, etching techniques and other processes that utilize a wide range of materials, including metals, semiconductors, ceramics, sol-gel materials and plastics.

[0007] In microsystems technology, various types of sensor elements are known, which are realized as microstructures:

[0008] Chemoresensitive gas sensors utilize semiconducting metal oxides such as tin(IV) oxide (SnCE) and copper(II) oxide (CuO) as sensor layers. These sensor layers respond to gases such as NOx (nitrogen oxides) by changing their electrical conductivity. Microstructures in these sensors comprise thin films of these metal oxides deposited onto substrates such as silicon or glass. The structure and surface morphology of these films, such as grain size and distribution, are controlled by techniques like sputtering and photolithography. These microstructures enable high sensitivity and selectivity for specific gases. Capacitive pressure sensors employ interdigital electrodes and dielectric layers, often composed of nanomaterials such as MXene and polyvinylpyrrolidone (PVP). These sensors measure pressure by changes in capacitance caused by mechanical deformation of the dielectric layer.The microstructures in these sensors comprise finely etched electrodes and nanostructured dielectric layers, fabricated using techniques such as inkjet printing and microelectromechanical systems (MEMS). These structures are designed to ensure high sensitivity and fast response times.

[0009] Platinum thin-film resistance temperature sensors (RTDs) consist of platinum thin films deposited on glass or silicon substrates. The microstructures of these sensors comprise fine platinum tracks created by sputtering and photolithography. These platinum tracks are often only a few hundred nanometers thick and form precise patterns that maximize the sensitivity and accuracy of the temperature measurement. Additional layers, such as chromium, act as adhesion promoters between the platinum and the substrate. Careful bake-out and calibration enhance the stability and reliability of these microstructures.

[0010] Overall, microstructures play a crucial role in the performance and miniaturization of the sensors described above. They enable not only high sensitivity and accuracy, but also integration into diverse structures.

[0011] Such sensors are described in the following documents:

[0012] The article "Neri, G. First Fifty Years of Chemoreresistant Gas Sensors. Chemosensors 2015, 3, 1-20. https: / / doi.org / 10.3390 / chemosensors3010001" describes the development of chemoreresistant gas sensors. Over the years, new nanoscale technologies have enabled significant changes in sensor development. Nanoscience and nanotechnology offer the ability to manipulate materials at the molecular level, leading to dramatic improvements in sensor size, weight, power consumption, sensitivity, and specificity. This has led to the development of sensors that can be integrated into clothing, smartphones, and other wearable devices. The article also discusses the different types of chemoreresistant gas sensors, including planar, flexible, and micromechanical elements (MEMS) sensors.It is noted that these sensors are widely used due to their low cost, simple manufacturing and small size, although they are less selective compared to other technologies such as electrochemical and optical sensors.

[0013] The article "Janosch Kneer, Stefan Knobelspies, Benedikt Bierer, Jürgen Wöllenstein, Stefan Palzer, New method to selectively determine hydrogen sulfide concentrations using CuO layers, Sensors and Actuators B: Chemical, Volume 222, 2016, pages 625-631, ISSN 0925-4005, https: / / doi.Org / 10.1016 / j.snb.2015.08.071" presents a method for the selective determination of hydrogen sulfide (H₂S) concentration using polycrystalline p-type semiconductor layers made of copper(II) oxide (CuO). Unlike conventional approaches that utilize the resistance of gas-sensitive metal oxide layers to measure trace gas concentrations, this method demonstrates that the effects of H₂S-induced phase transition percolation can be exploited. Using a thermal modulation protocol, the effects of the phase transition on the electrical behavior of the layer can be reversed, thereby restoring the initial state of the layer.This forms the basis for a method for gas detection using a semiconducting metal oxide layer.

[0014] The article "Janosch Kneer, Jürgen Wöllenstein, Stefan Palzer, Manipulating the gassurface interaction between copper(II) oxide and mono-nitrogen oxides using temperature, Sensors and Actuators B: Chemical, Volume 229, 2016, pages 57-62, ISSN 0925-4005, https: / / doi.Org / 10.1016 / j.snb.2016.01.104" investigates the effects of surface reactions of nitric oxide (NO) and nitrogen dioxide (NO₂) on p-type semiconducting copper(II) oxide (CuO) in different temperature ranges. It demonstrates that the gas-induced changes in the electrical conductivity of CuO upon NOx exposure can be altered from oxidizing to reducing and that the interaction can be effectively switched off. The results of the experiments show that the reaction of the CuO surface is mainly controlled by the chemical equilibrium of NO / NO2 and not by the specific adsorption processes of the metal oxide.These findings could help in developing temperature modulation schemes to improve the selectivity of metal oxide gas sensors. Furthermore, it is shown that the CuO material is capable of detecting low concentrations of NO / NO₂, with the strongest oxidation reaction occurring at 260°C and the strongest reduction reaction at 440°C for both oxides. Thanks to the high stability of the layer's base resistances, concentrations as low as 200 ppb can be detected. This study highlights the importance of surface morphology, which is influenced by the grinding process of the CuO particles. Different CuO surface morphologies are made accessible by adjusting the grinding time, providing an efficient way to optimize sensor properties.Investigating the temperature dependence of the sensor response reveals that at low temperatures the reaction of the layer is mainly controlled by chemical reactions on the surface, while at higher temperatures catalytic processes dominate, leading to a net reduction interaction.

[0015] The article "Qin, R., Hu, M., Li, X. et al. A new strategy for the fabrication of a flexible and highly sensitive capacitive pressure sensor. Microsyst Nanoeng 7, 100 (2021). https: / / doi.org / 10.1038 / s41378-021-00327-l" describes the development of a flexible and highly sensitive capacitive pressure sensor. It presents an approach that utilizes interdigital electrodes and a dielectric layer made from a mixture of MXene and polyvinylpyrrolidone (PVP). By increasing the number of interdigital electrodes and selecting a suitable dielectric layer, the sensitivity of the capacitive sensor can be significantly enhanced. The sensor can be used for various pressure detection applications, including finger pressure, wrist pulse measurement, respiration, swallowing, and speech recognition.The research provides a new approach to the production of highly sensitive capacitive sensors with promising application prospects in flexible sensors and wearable electronics.

[0016] The article "Aymen Zribi, Magali Barthes, Sylvie Begot, Francois Lanzetta, Jean Yves Rauch, Virginie Moutarlier, Design, fabrication and characterization of thin film resistances for heat flux sensing application, Sensors and Actuators A: Physical, Volume 245, 2016, pages 26-39, ISSN 0924-4247, https: / / doi.org / 10.1016 / j.sna.2016.04.040" describes the development, fabrication, and characterization of platinum thin-film resistance temperature sensors (RTDs) for use in heat flux sensing. It explains a microfabrication process in which thin films are analyzed using various methods such as scanning electron microscopy (SEM), X-ray diffractometry (XRD), and profilometry.

[0017] Based on this, the purpose of the invention is to enable efficient condition monitoring of a battery.

[0018] This problem is solved by the subject matter of the independent patent claims. Preferred further developments are found in the dependent claims.

[0019] According to the invention, a battery is proposed comprising a battery component, a sensor, two sensor electrodes, and an electrical conductor, wherein the sensor is integrated as a microstructure into the battery component, the two sensor electrodes are integrated into the battery component in such a way that they can be galvanically contacted from outside the battery components, and the electrical conductor connects the sensor to the sensor electrodes in such a way that it can be read via the electrical conductor.

[0020] In the case of a single sensor, the electrical circuit comprises two strands: one leading from one sensor electrode to the sensor itself, and another leading from the sensor to the other sensor electrode. The sensor signal can be read either resistively or capacitively.

[0021] In this context, the term "microstructure" is understood to refer to the precisely structured arrangement of components and layers used in microelectronic circuits, sensors, actuators, and other micromechanical systems. These microstructures are created using manufacturing techniques such as photolithography, etching, thin-film deposition, and micromilling. Microstructures in these applications enable the miniaturization and integration of complex functions in the smallest possible space, resulting in more powerful and compact devices, in this case, a battery with integrated condition monitoring capabilities.

[0022] It has been previously explained that the invention provides for the sensor to be integrated into the battery component as a microstructure. Likewise, the two sensor electrodes and / or the electrical conductor can of course be integrated into the battery component as a microstructure.

[0023] In principle, the invention is conceivable with only a single sensor. However, according to one embodiment of the invention, a plurality of sensors are integrated as microstructures into the battery component, with these sensors being connected in series between the sensor electrodes along the electrical conductor. In the case of a plurality of sensors, the electrical conductor comprises a plurality of strands, namely one leading from a sensor electrode to a first sensor in the series connection, strands between the sensors, and a strand leading from the last sensor in the series connection to the other sensor electrode.

[0024] It can be advantageous for reading the sensors if they have different impedances. It is possible that the sensors themselves already have different impedances. However, it is also possible that at least some of the sensors are equipped with an electrical resistor, inductor, and / or capacitor to adjust their respective impedances.

[0025] Sensors in the battery component can be used to measure various parameters. According to one embodiment of the invention, the sensor is a pressure sensor, and the area in the battery component between the pressure sensor and an outer surface of the battery component is porous. The porous area allows gas permeability, enabling the pressure sensor to be exposed to the gas to be measured.

[0026] Furthermore, it is preferred that the sensor(s), the sensor electrodes, and the electrical conductor are galvanically isolated from the battery component. In principle, various battery components are suitable, into which the microstructure is integrated. According to one embodiment of the invention, however, the battery component is the anode or the cathode of the battery.

[0027] The invention also relates to a method for manufacturing a battery component, comprising the following process steps:

[0028] Depositing a base structure forming part of the battery component, oxidizing areas on the base structure where a sensor is to be formed,

[0029] Deposition of structures to form the sensor on the oxidized area,

[0030] Oxidation of the still exposed area of ​​the sensor and

[0031] Deposition of a residual structure forming the remaining part of the battery component onto the still exposed oxidized areas of the sensor.

[0032] According to one embodiment of the inventive method, a region in the battery component between the sensor and an outer surface of the battery component is designed to be porous. In this way, the functionality of a gas sensor can be enabled.

[0033] The invention also relates to methods for reading a plurality of sensors, wherein the sensors are integrated as microstructures into a battery component of a battery, two sensor electrodes are integrated into the battery component in such a way that they can be galvanically contacted from outside the battery components, and the plurality of sensors are connected in series between the sensor electrodes along the electrical line, comprising the following method steps:

[0034] The sensors are read via the sensor electrodes and the electrical conductor using frequency division multiplexing. According to one embodiment of the invention, the frequency division multiplexing utilizes the resonant frequencies of the individual sensors.

[0035] According to this method, the sensors are read out as an electrical resonant circuit, for example, using a fixed capacitance and the resistive sensor itself. The resonance behavior depends on the actual sensor signal and, for example, the adjustable, fixed capacitive element. This allows the resistance values ​​of the sensors to be determined via the resonance behavior, which in turn exhibits characteristic changes for different sensor elements at different frequencies. Thus, with only two sensor electrodes and an analysis of the system's frequency response, the resistance of all sensors can be determined, and therefore all sensors can be read out.

[0036] The invention will now be explained in more detail using preferred embodiments and with reference to the drawings.

[0037] The drawings show

[0038] Fig. 1 schematically shows a battery according to an embodiment of the invention,

[0039] Fig. 2 schematically illustrates a manufacturing process for a battery component according to an embodiment of the invention.

[0040] Fig. 3 schematically shows a battery component according to an embodiment of the invention and

[0041] Fig. 4 schematically shows a selection method according to an embodiment of the invention using frequency division multiplexing.

[0042] Figure 1 schematically shows a battery 1 according to an embodiment of the invention. The battery 1 comprises a battery component 2, a sensor 3, two sensor electrodes 4, and an electrical conductor 5. The battery 1 itself is only indicated, and components other than those mentioned above are not shown. In this case, the battery component 2 is the cathode of the battery 1. Crucially, the sensor 3 is integrated as a microstructure into the battery component 2, the two sensor electrodes 4 are integrated into the battery component 2 in such a way that they can be galvanically contacted from outside the battery component 2, and the electrical conductor 5 connects the sensor 3 to the sensor electrodes 4 in such a way that the sensor 3 can be read via the electrical conductor 5.In this way, a sensor 3 is provided which can be easily integrated into the battery 1 and thus enables efficient condition monitoring of the battery 1.

[0043] As can be seen in Fig. 3, it is also possible to integrate a plurality of sensors 3 as microstructures into the battery component 2. In this case, the sensors 3 are connected in series between the sensor electrodes 4 along the electrical conductor 5. As indicated in the upper right of Fig. 3, each sensor 3 can be described as a parallel circuit of a resistor and a capacitor. Typically, due to different resistances and / or capacitances, the sensors 3 also have different impedances, which can be used for reading the sensors 3. If the impedances of two sensors 3 are indeed the same or very similar, each sensor 3 can be equipped with an additional electrical resistor, an additional inductor, and / or an additional capacitor to adjust its respective impedance.

[0044] If the sensor 3 is designed as a pressure sensor, the area in the battery component 2 between the pressure sensor 3 and an outer surface of the battery component 2 is made porous in order to achieve gas permeability and thus allow the sensor 3 to be exposed to the gas surrounding the battery component 2.

[0045] In the present case, where the battery component is the cathode of battery 1, the sensors 3, the sensor electrodes 4, and the electrical conductor 5 are galvanically isolated from the battery component 2. The manufacture of the sensor 3 and the corresponding galvanic isolation are described below with reference to a manufacturing process schematically illustrated in Fig. 2 according to an embodiment of the invention. The individual, successive process steps are shown there from top to bottom. This process for manufacturing a battery component 2 in the form of a cathode of battery 1 comprises the following process steps.

[0046] In a first step, a basic structure 10 in the form of aluminum, forming part of the battery component 2, is deposited. This is followed by the oxidation of areas 11 on the basic structure 10, in which a sensor 3 is to be formed. Next, structures 12 for the formation of the sensor 3 are deposited on the oxidized area 11. Then, a further oxidation takes place, namely the oxidation of the previously exposed areas 13 of the sensor 3. Finally, a residual structure 14, forming the remaining part of the battery component 2, is deposited on the still exposed oxidized area 13 of the sensor 3. In the case of a pressure sensor, a porous area in the battery component 2 between the sensor 3 and an outer surface of the battery component 2 is then made porous.

[0047] With regard to reading a series connection of sensors 3 shown in Fig. 3, the present invention, according to one embodiment, takes advantage of the fact that the sensors 3 generally have different impedances or can be equipped with different impedances. The sensors 3 are read via the sensor electrodes 4 and the electrical line 5 by means of frequency division multiplexing, whereby the frequency division multiplexing utilizes the different resonant frequencies of the individual sensors 3, as shown by way of example for two different sensors 3 in Fig. 4.

[0048] Reading a series connection of sensors 3 by frequency division multiplexing is thus made possible by the differing resonant frequencies of various parallel resonant circuits formed by the different sensors. The resonant frequency f rThe oscillation of a single parallel resonant circuit is derived from Thomson's oscillation equation: with capacitance C and inductance L. If the inductance or capacitance of the parallel resonant circuit changes, the resonant frequency changes accordingly. Here, several sensors 3, corresponding to a parallel resonant circuit, are connected in series. When examining the impedance curve of the series circuit as a function of frequency, the individual resonant frequencies become visible, specifically at different frequencies. By changing, for example, the capacitances, the resonant frequencies of the individual parallel resonant circuits can be adjusted.

[0049] The frequency-dependent magnitude of the impedance |Z( ) | of a parallel resonant circuit can be determined via describe, where R describes the electrical resistance of the parallel resonant circuit.

[0050] With the resonance frequency f mentioned above r The impedance is then calculated as and thus corresponds solely to the resistance R of the parallel resonant circuit.

[0051] Furthermore, the capacitance can be determined via the determined resonance frequency of a sensor. be calculated and with The inductance. The resonant frequency can also be determined via the phase angle. This is 0° at resonance.

[0052] When several sensors are connected in series, the result is a total impedance that has its maxima at the resonant frequencies of the individual parallel resonant circuits:

[0053] The individual sensors 3 do not necessarily need to have an additional resistor, inductor, and / or capacitor. Real sensors 3 typically possess parasitic properties that alone lead to corresponding resonant frequencies.

[0054] Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Climate, Infrastructure and Environment Executive Agency (CINEA). Neither the European Union nor the granting authority CINEA can be held responsible for them.

[0055] Reference symbol list

[0056] 1 battery

[0057] 2 Battery component 3 Sensor

[0058] 4 sensor electrodes

[0059] 5 electrical lines,

[0060] 10 Basic structure

[0061] 11 oxidized areas on the base structure 12 structures for forming the sensor, the sensor electrodes and the electrical conduction on the oxidized areas

[0062] 13 oxidized area of ​​the sensor, sensor electrodes and electrical conductor

[0063] 14 Residual structure

Claims

Patent claims 1. Battery (1), comprising a battery component (2), a sensor (3), two sensor electrodes (4) and an electrical conductor (5), wherein the sensor (3) is integrated as a microstructure into the battery component (2), the two sensor electrodes (4) are integrated into the battery component (2) in such a way that they can be galvanically contacted from outside the battery component (2), and the electrical conductor (5) connects the sensor (3) to the sensor electrodes (4) in such a way that it can be read via the electrical conductor (5).

2. Battery (1) according to claim 1, wherein a plurality of sensors (3) are integrated as microstructures into the battery component (2), wherein the sensors (3) are connected in series between the sensor electrodes (4) along the electrical line (5).

3. Battery (1) according to claim 2, wherein at least part of the sensors (3) is provided with an electrical resistance, an inductance and / or a capacitance for adjusting their respective impedance.

4. Battery (1) according to one of the preceding claims, wherein the sensor (3) is a pressure sensor and the area in the battery component (2) between the pressure sensor (3) and an outer surface of the battery component (2) is porous.

5. Battery (1) according to one of the preceding claims, wherein the sensor (3) or sensors (3), the sensor electrodes (4) and the electrical conductor (5) are galvanically isolated from the battery component (2).

6. Battery (1) according to any of the preceding claims, wherein the battery component (2) is the anode or the cathode of the battery (1).

7. Method for manufacturing a battery component (2), comprising the following process steps: Deposition of a basic structure (10) forming part of the battery component (2), Oxidation of areas (11) on the base structure (10) in which a sensor (3) is to be formed, Deposition of structures (12) to form the sensor (3) on the oxidized area (11), Oxidation of the previously exposed area (13) of the sensor (3), and Deposition of a residual structure (14) forming the remaining part of the battery component (2) onto the still exposed oxidized area (13) of the sensor (3).

8. Method according to claim 7, wherein a region in the battery component (2) between the sensor (3) and an outer surface of the battery component (2) is designed to be porous.

9. Method for reading a plurality of sensors (3), wherein the sensors (3) are integrated as microstructures into a battery component (2) of a battery (1), two sensor electrodes (4) are integrated into the battery component (2) such that they can be galvanically contacted from outside the battery component (2), and the plurality of sensors (3) are connected in series between the sensor electrodes (4) along the electrical line (5), comprising the following method steps: Reading the sensors (3) via the sensor electrodes (4) and the electrical line (5) using frequency multiplexing.

10. Method according to claim 9, wherein the frequency division multiplexing utilizes the resonance frequencies of the individual sensors (3).

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