SENSOR SYSTEM FOR MEASURING THE INTERNAL BATTERY CONDITION

Abstract

Vehicle comprising: an electric motor; a battery for storing electrical energy for the electric motor; and an acoustic surface wave sensor for wirelessly detecting a magnetic field of the battery and the battery temperature, wherein the sensor includes a reactive magnetic field device for modifying a surface wave in response to the magnetic field depending on the lithiation of an electrode of the battery, wherein the acoustic surface wave sensor includes a plurality of sound reflectors and converts an input signal into an acoustic surface wave signal which is reflected by the reflectors to generate a response signal and is modified by the reactive magnetic field device, wherein the reactive magnetic field device includes a giant magnetoimpedance thin film, and wherein the surface wave sensor has a mechanical damper adjacent to one of the sound reflector and giant magnetoimpedance thin film.

Description

TECHNICAL AREA

[0001] Various embodiments relate to systems and methods for detecting battery condition and a vehicle using such systems and methods. BACKGROUND ART

[0002] Batteries used in vehicles can be monitored using various sensors to determine physical characteristics of the battery. The temperature of a battery can be approximated by measuring a thermistor on the bus bar attached to a battery; Temperature sensors can also be attached directly to the cell housing. The battery cell voltage can be measured using a chip that spans a plurality of battery cells connected with physical wiring through a battery case and uses electric power from the battery cell itself. The present technique for current measurement uses either a resistive shunt or a Hall effect current sensor that creates a difference in electrical voltage across the sides of a live conductor connected to the battery. As it is desired to increase the efficiency of battery powered vehicles, more accurate data regarding physical battery conditions can lead to improved performance. EXECUTIVE SUMMARY

[0003] Systems and methods for detecting the internal conditions of batteries for vehicles are described. From this internal status information, different physical properties of the batteries can be measured, calculated or derived.

[0004] An electric vehicle, e.g. B. a hybrid electric vehicle (hybrid electric vehicle - HEV), an electric motor, a battery to store electrical energy for the electric motor, and a sensor connected to the battery to detect a battery condition to receive an input signal , and to wirelessly transmit an output signal indicative of battery condition, and a control circuit to receive the output signal and to control the electric motor and the battery. In certain examples, the battery may have a physical property that changes based on a condition of the battery. This physical property can be measured by the sensor. The sensor can be passive or built into the structure of the battery.

[0005] In one example, an electric or hybrid vehicle may include an electric motor; a battery to store electric power for the electric motor; and a surface acoustic wave sensor to wirelessly detect a magnetic field of the battery and the battery temperature, the sensor including a reactive magnetic field device to change a surface acoustic wave in response to the magnetic field.

[0006] In one example, the sensor includes a passive radio frequency identification tag.

[0007] In one example, the control circuit is configured to control the electric motor and the battery based on an output signal from the surface acoustic wave sensor.

[0008] In one example, the control circuit determines a battery condition from an output signal of the surface acoustic wave sensor.

[0009] In one example, the battery condition is state of charge (SOC) or state of health (SOH).

[0010] In one example, the sensor is embedded in a housing of the battery and communicates wirelessly with the control circuitry of the electric motor.

[0011] In one example, the sensor includes a plurality of acoustic reflectors and is further configured to convert an input signal into a surface acoustic wave signal, which is reflected by the reflectors to generate the response signal and modified by the reactive magnetic field device.

[0012] In one example, the reactive magnetic field device includes a giant magnetoimpedance (GMI) thin film.

[0013] In one example, a mechanical damper resides on the surface acoustic wave (SAW) substrate adjacent to the GMI film and the matching circuitry that electrically connects the GMI film to the acoustic reflector.

[0014] In one example, the acoustic reflector includes an interdigitated reflector with a spigot having a thickness of λ / 8 relative to a signal on the SAW substrate. Note that λ is the wavelength of the propagating wave.

[0015] In one example, the surface acoustic wave sensor includes circuitry to convert the detected magnetic field into an output voltage.

[0016] The present description further includes a battery monitoring system that may include a surface acoustic wave sensor to wirelessly detect a battery condition, which also includes a magnetic field detection device to modify a SAW signal based on a magnetic field at a battery electrode, a temperature sensor to detect the temperature at a detecting a battery and having a transducer to wirelessly output an output signal that includes temperature and battery condition; and a control circuit to convert the detected magnetic field into an output voltage signal.

[0017] In one example, the sensor includes a passive radio frequency identification tag.

[0018] In one example, the output voltage represents the strength of the magnetic field, which is directly related to the degree of lithiation in the battery. A state of charge (SOC) or state of health (SOH) of the battery may be correlated or determined from the output voltage signal.

[0019] In one example, the sensor is embedded in a housing of the battery.

[0020] In one example, the sensor includes a plurality of acoustic reflectors and the magnetic field detection device includes a GMI film bonded to at least one of the acoustic reflectors.

[0021] In one example, the magnetic field detection device includes a mechanical damper abutting one of the acoustic reflector and GMI film.

[0022] In one example, the magnetic field detection device includes a matching circuit connected to the reflector and the GMI film.

[0023] In one example, the transducer includes conversion circuitry to convert the detected magnetic field into an output signal to be wirelessly transmitted from the surface acoustic wave sensor to external circuitry on a vehicle.

[0024] In one example, the acoustic reflector includes an interdigitated reflector with a spigot having a thickness of λ / 8 relative to a signal on the SAW substrate.

[0025] In one example, the SAW sensor is calibrated to set the two extreme deflections of the sensor to represent 0% lithiation and 100% lithiation at the battery terminal as the two extreme positions of the sensor. These two extreme positions of the sensor allow the sensor to be within the detection range such that it can more accurately detect the degree of lithiation, which can be used to infer battery capacity and state of charge.

[0026] The present disclosure also describes a rechargeable battery monitoring system, which may include any of the above examples. Such a monitoring system can be used with a vehicle such as an automobile, a hybrid electric vehicle, a portable electronic device, a mobile communication device, and the like.

[0027] A battery condition determination method is also disclosed and may wirelessly transmit an input signal, receive the input signal by a passive sensor connected to a battery, output an output signal that changes based on a module of the battery, and determine the battery condition using the output signal . character list figure 1 is an example electric vehicle with a battery pack. figure2 is a battery pack assembly consisting of battery cells and battery cell monitoring and control systems. the figure 3A and figure 3B show a sensor according to the teachings herein having a different sensor reading based on a physical property of a battery cell. figure 4 is a view of a sensor for use with a battery cell according to an example embodiment. figure 5 is a view of a sensor for use with a battery cell according to an example embodiment. figure 6 is a view of a sensor for use with a battery cell according to an example embodiment. figure 7 is a schematic view of a battery sensor system for an electric vehicle according to an example embodiment. figure 8 is a schematic view of a reference circuit for an electric vehicle battery sensor system according to an example embodiment. figure 9 shows a course of the field strength and the output voltage for a battery sensor according to an exemplary embodiment. DETAILED DESCRIPTION

[0028] The present specification lists embodiments of the present invention herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be enlarged or reduced to show details of particular components. Accordingly, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching those skilled in the art how to variously utilize the present invention. It will be appreciated by those of ordinary skill in the art that different features illustrated and described with reference to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described will. The combinations of features illustrated provide representative embodiments for typical applications. However, different combinations and modifications of the features consistent with the teachings of this disclosure may be desirable for particular applications or implementations.

[0029] figure 1 forms an example of an electric vehicle system 100 away. The system 100 can an electric vehicle 100 that may be a hybrid electric vehicle, an all-electric vehicle, or the like with a traction battery. The system 100 can also be a power source 126 involve to the electric vehicle 102 charge. The electric vehicle 102 can have one or more electric motors 104 include the mechanical with a hybrid transmission 106 are connected. In addition, the hybrid transmission 106 mechanical with a motor 108 , for example an internal combustion engine. The hybrid transmission 106 can also be mechanical with a drive shaft 110 be connected mechanically to the wheels 112 connected is. The electric motors 104 can provide propulsion when the engine 108 is turned on. The electric motors 104 can provide braking capability when the motor 108 is switched off. The electric motors 104 can also be configured as generators and can provide fuel efficiency benefits by recovering energy that would normally be lost as heat in a friction braking system. The electric motors 104 can also reduce pollutant emissions, since the electric vehicle 102 can be operated in an electric mode under certain conditions.

[0030] The traction battery or battery pack 114 stores energy by the electric motors 104 can be used. A vehicle battery pack 114typically provides a DC high voltage output, e.g. B. in different examples greater than 100 volts, greater than 200 volts, greater than 300 volts. The battery pack 114 is electrical with a power electronics module 116 tied together. The power electronics module 116 is also electric with the electric motors 104 connected and provides the ability to transfer energy bi-directionally between the battery pack 114 and the electric motors 104 transferred to. For example, a battery pack 114 provide a DC voltage while the electric motors 104 may require three-phase AC power to operate. The power electronics module 116 can convert the DC voltage into a three-phase AC current, as by the electric motors 104 required, for example by using an inverter module. In a regeneration mode, the power electronics module 116 the three-phase alternating current from the electric motors 104 , which act as generators, into the DC voltage generated by the battery pack 114 is required, using an inverter module or other circuit. The methods described herein are equally applicable to pure electric vehicles or any other device that uses battery packs.

[0031] In addition to providing drive energy, the battery pack 114 Provide energy for other electrical vehicle systems. Such a system can be a DC / DC converter module 118 contain the high voltage DC output of the battery pack 114 to a low voltage DC power supply compatible with other vehicle loads. Other high voltage loads such as compressors and electric heaters can be connected directly to the battery pack high voltage bus 114 to be connected. In a vehicle, the low voltage systems are electrically connected to a 12V battery 120 . A pure electric vehicle can have a similar architecture but without the motor 108 .

[0032] The battery pack 114 can by an external power source 126 be loaded again. The external power source 126 can the vehicle 102 Provide direct current or alternating current by being electrically charged via a charging port 124 connected is. The charging port 124 can be any type of connector designed to receive power from the external power source 126 to the vehicle 102 transferred to. The charging port 124 can be electric with a power conversion module 122 to be connected. The power conversion module can convert the power from the external power source 126 condition to the battery pack 114 provide the correct voltage and current levels. In some applications, the external power source 126 be designed to the battery pack 114 providing the correct voltage and current levels, and the power conversion module 122 may not be necessary. The functions of the power conversion module 122 can in some applications from the external power source 126 be taken over. The vehicle's engine, transmission, electric motors, battery, power conversion, and power electronics may be controlled by a powertrain control module (PCM) 128 .

[0033] The battery pack 114 may include a plurality of cells having electrodes to electrically connect the cell to other circuitry. Battery parameters and battery status can be detected by placing passive sensors in the battery pack or in each battery cell. A signal external to the battery can interrogate the sensor. In one example, the signal also powers the sensor. The sensor may include radio frequency identification tag devices, as well as battery detection circuitry and other technological devices. The sensor then sends a detected signal outside of the battery pack to a receiver that is connected to other vehicle circuitry.

[0034] In addition to illustrating a plug-in hybrid electric vehicle, figure 1 illustrate a battery electric vehicle (BEV) when the motor 108 was removed. Equally can figure 1 illustrates a conventional hybrid electric vehicle (HEV) or a power-split hybrid electric vehicle when components 122, 124, and 126 have been removed. figure 1 also illustrates the high voltage system, the electric motor(s), the power electronics module 116 , the DC-DC converter module 118 , the power conversion module 122 and the battery pack 114 contains. The high voltage system and battery pack includes high voltage components that include bus bars, high voltage connectors, high voltage cables, and circuit interrupters.

[0035] The individual battery cells within a battery pack can be made up of a variety of chemical compositions. The battery pack chemistry may include lithium ion, lithium ion polymer, lead acid, nickel cadmium (NiCd), or nickel metal hydride (NIMH), among others. figure 2 shows a battery pack 200 in a simple series configuration of N battery cell modules 202 . The battery cell modules 202 may contain a single battery cell or multiple battery cells electrically connected in parallel with the connections being made at the electrodes. However, the battery pack may consist of any number of individual battery cells and battery cell modules connected in series or parallel or a combination thereof. A system may include one or more controllers, such as a battery control module (BCM) 208 that controls the performance of the battery pack 200 monitors and controls. The BCM 208 can monitor multiple battery pack level characteristics, such as pack current measured by a current sensor 206 is measured, the pack tension 210 and the pack temperature 212 . The performance of the current sensor 206 can be used in certain arrangements to build a reliable battery monitoring system. Current sensor accuracy can be helpful in estimating battery charge and capacity status. A current sensor can use a number of methods based on physical principles to sense current, including a Hall Effect IC sensor, a transducer or current clamp, a resistor in which the voltage is directly proportional to the current flowing through it, fiber optic cable, that use an interferometer to measure the phase change in the light produced by the magnetic field or include a Rogowski coil. When a battery cell is charging or discharging in such a way that the current entering or leaving the battery cell exceeds a threshold value, the battery control module can interrupt the battery cell through the use of a circuit interrupt device (CIP), such as a fuse or a circuit breaker.

[0036] The battery cell may exhibit physical changes, such as swelling and contraction (which changes the cell's Young's modulus) as the state of charge changes. In the case of a lithium (Li) ion battery including an electrode made of metal oxides and lithium ions, lithium is introduced into and extracted from the electrode during discharging and charging, respectively. This process causes microstructural changes (swelling and contraction) that change the modulus (a material property) of the electrode. For example, the modulus of graphite increases with the incorporation of lithium. The Young's modulus for a graphite electrode changes by almost a factor 3 , when full of lithium. The modification of the module can be carried out according to the systems and methods described herein, e.g. B. a sensor on or in the battery cell or the battery pack can be measured.

[0037] In addition to the pack level characteristics, there may be battery cell level characteristics that need to be measured and monitored. For example, the terminal voltage, current, and temperature of each cell or a representative subset of cells can be measured. A system can have a sensor module 204 use to determine the properties of one or more battery cell modules 202 to eat. The properties can include the voltage, temperature, age, number of charge / discharge cycles, etc. of the battery cell. In one example, a sensor module 204 measure the battery cell voltage. Battery cell voltage can be the voltage of a single battery or a group of batteries electrically connected in parallel or in series. The battery pack 114 can up to N c sensor modules 204 use to determine the characteristics of a representative sample of all battery cells 202 to eat. The sensor modules 204 can battery cell sensors 220 communicate. The battery cell sensors 220 - 1 , 220 - 2 , ..., 220-N - 1 and 220-N are fixed with each battery cell 1 , 2 , N-1, N connected. The battery cell sensors can be passive sensors, e.g. B. radio frequency identification tags, surface acoustic wave sensors or other similar sensors integrated into the battery cell structure. The battery cell sensors 220 can detect a physical property of the battery cell and generate an output signal that from the sensor module 204 received in response to the measured physical property of the battery cell. Each of the sensor modules 204 can send the measured values ​​to the BCM for further processing and coordination 208 transfer. The sensor module 204 can send signals in analog or digital form to the BCM 208 transfer. The battery pack 114 may also include a battery distribution module (BDM) 214 that controls the flow of current into and out of the battery pack 114 controls.

[0038] the figure 3A and figure 3B show the sensor 301 according to the teachings herein for reading a physical property of a battery cell. the sensor 301 adjacent to the battery cell 220 on. the sensor 301 can a signal 305 ( 305' in figure 3B) to determine the characteristics of the battery. the sensor 301 can be a tunneling magnetoresistance (TMR) device with two magnetic layers (e.g. ferromagnets such as CoFeB) separated by a thin insulator (e.g. MgO which is a few atoms thick) producing a magnetic field radiate and recognize. A TMR device uses a quantum mechanical process to read the magnetic field through a process called tunneling. A polarization voltage is created between the metals by allowing current to flow across the insulator. The probability of quantum tunneling is directly related to electron spin alignment, which can be influenced and controlled by introducing external magnetic fields with the following effects: as the strength of the magnetic field increases, the electron spin alignment increases and more electrons can tunnel across the insulator. As more electrons tunnel across the insulator, the resistance of the device decreases. Accordingly, the magnetoresistance of the sensor is the first indication of its performance: for example, anisotropic sensors 2 -3% Magnetoresistance up, while giant sensors 15 Have -20% magnetoresistance. In contrast, sensors that implement magnetic tunnel junctions have a magnetoresistance of 200%.

[0039] In one example, the sensor 301 adjacent to an electrode 306 of the battery within a battery case 307 positioned. A physical property of the electrode 306 in a first state results in a first signal field 305 . A change in the physical property of the lead 306 in a second state results in a second signal field 305'. In one example, the electrode includes 305Battery anode materials for lithium (Li) ion batteries and includes metal oxides and lithium ions that can be easily incorporated into and extracted from the oxides. Lithium is a paramagnetic material and therefore the anode magnetic properties (i.e. magnetic susceptibility) change during charge and discharge cycling. In the presence of a magnetic field 305 the anode is magnetized. The magnetic field 305 for a fully charged battery can be used as an output value ( figure 3A) can be recognized and used. When the battery is discharged, the magnetic field will be disturbed 305' and the state of charge (SOC) of the battery will be reduced, as in figure 3B, measure directly. figure 3A shows the response of a magnetic field 305 on a battery whose SOC is 100%. figure 3B shows the response of a magnetic field 305' on a battery whose SOC is 20%. A battery with a lower charge will have a measurable increase in magnetic susceptibility and therefore there will be a larger magnetic field compared to batteries with higher charge levels. In the present example, the battery electrode of a battery with a 20% state of charge exhibits a threefold increase in magnetic susceptibility compared to one that is fully charged.

[0040] The positive electrode, i. H. a metal oxide, and a lithium ion (Li + ) of lithium ion batteries are paramagnetic materials because of their electronic structure. The lithium ions can be easily extracted from and introduced into the oxides during the charge / discharge cycle. This results in the changing magnetic properties (i.e., magnetic susceptibility) of the positive electrode. In the presence of a magnetic field, the positive electrode becomes magnetized. The magnetic field for a fully charged battery can be detected and used as a baseline for analysis as described herein. When the battery is charged / discharged, the magnetic field is increased by the extraction / introduction of Li + be disturbed and this will directly measure the degree of lithiation. The level of lithiation is related to the SOC and degradation of the battery. Lithiation can represent the level or amount of lithium that is incorporated into a battery electrode.

[0041] the figure 3A and figure 3B show the response of the magnetic field of a fully charged battery (100% SOC) to that of a discharged one (e.g. 20% SOC). In the present example, a positive electrode of a 20% SOC battery exhibits about a three-fold increase in magnetic susceptibility compared to one that is fully charged. While the example above describes lithium ion batteries, this detection principle can be used for detecting other types of batteries that use paramagnetic electrode materials, e.g. B. Lead-acid batteries.

[0042] In addition, the proposed technique can also be used to more accurately determine battery capacity over time. It is well known that battery performance will degrade over time due to capacity loss and impedance increase. A major cause of capacity loss is the loss of active lithium. It is critical for the battery management system (BMS) to track the real-time capacity change for batteries used across a wide SOC range, such as PHEV or BEV. The proposed technique avoids the errors mentioned in the problem description above by directly measuring the lithium content at the minimum and maximum battery voltage thresholds.

[0043] While the example above describes lithium ion batteries, this technique can be used for detecting other types of batteries, e.g. B. lead-acid batteries and lithium iron phosphate batteries.

[0044] the sensor 301 can be a passive sensor that does not need to emit a signal and detects the magnetic field of the battery electrode. The change in the detected magnetic field may indicate a change in a physical property of the battery.

[0045] The SAW sensor is in use 301calibrated to set the two extreme deflections of the sensor to represent 0% lithiation and 100% lithiation at the battery terminal as the two extreme positions of the sensor. These two extreme positions of the sensor allow the sensor to be within the detection range such that it can more accurately detect the degree of lithiation, which can be used to infer battery capacity and state of charge.

[0046] figure 4 shows a schematic view of a sensor 400 for a battery or battery cell. The sensor can be a surface acoustic wave sensor. the sensor 400 can orthogonal frequency coding (OFC) of a single port with double delay with multiple reflectors on the substrate 406 include. Other wireless coding can be used to send information and energy signals to the sensor 400. The reflectors can be integrated circuits, microelectromechanical systems or the like. A device package 407 supports the substrate 406 such at one end portion that the other end is cantilevered and can deflect. The deflection motion can be detected and the resulting data can represent battery conditions or other information. The substrate 406 In one example, a YZ-LiNbO 3 -Be structure. In figure 4 are three reflectors as an OFC bank (403 1 -403 6 ) for a total of six reflectors in two banks on opposite sides of the transducer 409 shown. The chips 403 1 -403 6 may be surface acoustic wave devices that generate a surface wave from a transducer 409 receive and send a signal to the converter 409 return displaying information pertaining to the battery. The battery can put a load on the SAW substrate 406 exercise, which are caused by the signal to / from the reflectors 403 1 -403 6 is recognized. The Bank of Reflectors 403 1 , 4033 and 403 5 are positioned at an end portion of the substrate leading directly from the package 407 will be carried. The reflectors 403 1 , 4033 and 403 5 can measure the temperature on the battery, either inside the battery adjacent to the internal battery chemistry or on the battery packaging or battery case. The reflectors 403 1 , 403 3 and 403 5 can also provide an unloaded or offset output signal used in determining load or offset at one end of the sensor 400 can be used. The second bank of reflectors 403 2 , 403 4 and 403 6 are positioned at the end portion of the substrate not directly from the package 407 will be carried. The second bank of reflectors 403 2 , 403 4 and 403 6 are one end of the substrate 406 , which is the free end of the cantilevered substrate. The reflectors 403 2 , 403 4 and 403 6 can measure the stress experienced by the substrate, either in the battery adjacent to the internal battery chemistry or on the battery packaging or case. In one example, exposure to a magnet 408 caused, which is positioned at the free end of the cantilever substrate. The magnet 408 creates a magnetic field and detects changes in the battery via the electromagnetic fields in the battery. In one example, the magnet detects 408 the magnetic field in the adjacent area of ​​the vehicle battery. If the magnet 408 interacts electromagnetically with the magnetic field of the battery, the substrate is moved and its displacement can be detected by the reflectors 403 2 , 403 4 and 403 6 be recognized. Although described herein as reflectors, the reflectors 403 1 -403 6 include electronic structures, MEMS structures, or combinations thereof. the sensor 400 may include the interdigitated transducers as described herein.

[0047] Surface acoustic wave (SAW) based devices, which can be configured for either wired or wireless operation, provide a sensor platform for measuring active lithium concentration via magnetic field detection. These sensors are based on the piezoelectric effect, whereby the signal propagation speed of a SAW in a piezoelectric substrate changes in response to surface disturbances. SAW devices are sensitive to temperature, pressure, strain, fluid viscosity, and surface effects. To measure the magnetic field response for a charged / discharged cell, the surface of the SAW must be modified with a magnetic element to convert the magnetic field change into a surface perturbation. In different examples, the propagation path can be superimposed in the SAW substrate with a magnetoresistive (MR) layer, a giant magnetoimpedance (GMI) film, or by embedding a permanent magnet in a cantilever structure of the SAW substrate, as shown in FIGS figure 4 to figure 6 is illustrated accordingly. Among the available magnetic field sensors, the SAW-based thin-film GMI offers advantageous properties such as high-frequency sensitivity to the magnetic field, compatibility with high-frequency processes and standard microfabrication procedures, and easy incorporation into SAW devices and electronic circuits.

[0048] figure 5 shows a schematic view of a sensor 500 for a battery or battery cell similar to the sensor 400 is described above with reference to figure 4 has been described. the sensor 500 includes a layering device 520 , which can be a magnetoresistive (MR) film or a giant magnetoimpedance (GMI) film, which can change the perturbation of the signal at the SAW substrate in response to the magnetic field of an electrode of a battery cell. the sensor 500 includes a second layer device 525 , which can be a magnetoresistive (MR) film or a giant magnetoimpedance (GMI) film, which can change the perturbation of the signal at the SAW substrate in response to the magnetic field of an electrode of a battery cell. The SAW sensor 500 can use one or both devices 520 and 525 exhibit. The first device 520 can toward the center of the SAW substrate 406 be placed, e.g. B. adjacent to the input / output converter 409 or between the converter 409 and the load detection device 403 2 , 403 4 and 403 6 . The second device 525 can otherwise on the SAW substrate 406 be positioned.

[0049] figure 6 shows a schematic view of a sensor 600 for a battery or battery cell. the sensor 600 may be a surface acoustic wave sensor similar to the sensors described above 400 , 500 is.

[0050] figure 7 show a vehicle subsystem 700 with a SAW sensor subsystem 702 with a magnetic field sensor and with an electronic control module 703 . In various embodiments described herein, the magnetic sensor element consists of a GMI thin film sensor built into the SAW system. In an exemplary embodiment, the magnetic sensor element may only be a GMI sensor. As previously mentioned, the built-in SAW GMI sensor can be wireless.

[0051] In order to obtain a high sensitivity to the magnetic field, the GMI sensor 714 is adapted to the output port, e.g. B. the converter 409 ( figure 6) to the operating frequency of the SAW system, e.g. B. 400, 500 or 600. If the impedance of the GMI sensor 714 changes with the applied magnetic field of the battery, the match deteriorates, causing the amplitude of the signal from the reflectors 403 2 , 403 4 or 403 6 to be reflected in order to change. Since the piezoelectric material is resistant to environmental changes, e.g. B. temperature, is sensitive, a reference reflector 403 1 , 403 3or 4035 (e.g. an interdigitated transducer) is used to provide a signal allowing extraction of the active lithium concentration. Mechanical dampers, e.g. B. 604, next to the input and output reflector 403 2 , 403 4 or 4036 suppress reflections from other structures on the substrate or the edge of the substrate. In one example, the sensor load is at an optimal working point of the reflector 403 4 customized. Since the GMI sensor 605 is an inductive element, the matching is achieved by a series capacitor, resulting in a load impedance determined by the following equation Z = 1 / j ω C m + R + j ω L ( H e x t ) where C m is the matching capacitor, R is the average resistance (over the magnetic field range under consideration) of the GMI sensor, and L(H ext ) is the inductance of the GMI sensor.

[0052] Referring again to figure 7 is the battery control module 703 a control module in the electrified vehicle that receives information in analog format from the SAW GMI sensor system 702 receives. In this example there are three communication channels 731 , 732 , 733, which the BCM 8 with the SAW-GMI sensor system 702 associate. The signal CS_VREF on the communication channel 731 represents the SAW-GMI sensor system 702 a power supply and an accuracy reference from the control module 703 ready. In operation, the control module 703 a power source ready that it circuits in the SAW-GMI sensor system 702 enabled to operate. In one example, the signal CS_VREF is a combination of power supply and reference voltage to the SAW GMI sensor system. The ground reference for the SAW-GMI sensor system is on the communication channel 732 and is the signal CS_REF. The third communication channel 733 includes an analog output signal to a digital output signal from the SAW-GMI system 702. In one example, the output signal is on the channel 733 a voltage ranging from 0 volts to CS-VREF volts. It is understood that the magnetic field from the lithiation in the battery or battery cell through the SAW-GMI sensor system 702 is measured and the information about this field through the circuits in the SAW-GMI sensor system 702 is encoded into an instantaneous voltage known as CS-AOUT on the channel 733 appears. In one example, a concrete mathematical relationship exists between the instantaneous value of the magnetic field that the SAW-GMI element 714 traverses, and an instantaneous voltage of CS_AOUT on the third channel 733 .

[0053] The SAW GMI element 714 can the reflector 403 , which include matching circuitry, the GMI sensor and optionally a mechanical damper, communicating with a transducer using the channels 731 , 732 , 733 can communicate. In one example, a digital processor receives 715 an output from the SAW-GMI element 714 and processes the signal from the SAW-GMI element 714 , e.g. B. using the mathematical relationship. The mathematical relationship may be in the form of instructions for processing the signal from the SAW-GMI element into an output to digital-to-analog converter 722, which may also include memory that can act as an input buffer or an output buffer. The digital processor 715 can also store a look-up table that allows an input to correlate with an output based on the mathematical relationship.

[0054] The control module 703 includes a buffer and filter circuit 744 , which is a connector of the third channel 733 is. The buffer and filter circuit 744 receives the output signal representing the measured value of battery lithiation. When the output signal from SAW-GMI sensor system 702 is an analog signal, an analog to digital converter 745 receives the signal from the buffer and filter circuit 744 . If the buffered and filtered signal, which is the voltage signal CS_AOUT on the third channel 733is digital, then the buffer and filter circuitry can be directly connected to the main controller 750 to be connected. Otherwise, the A / D converter 745 gives a digital signal to the controller 750 out. In one example, the A / D converter 745 is actually within the main controller 750 contain. The main control 750 may include processors, memory, and other circuitry to receive inputs and generate output control signal(s) to the vehicle modules that include estimates of SOC, charge capacity, and other battery health information, at least some of which is derived from measurement by the SAW-GMI element 714 dependent on or derived from it.

[0055] The control module 703 can also use the reference circuit 755 include the SAW GMI sensor 702 provides a combined power supply and accuracy reference signal, e.g. B. on the first communication channel 731 and the second communication channel 732 . The reference circuit may be connected to vehicle ground and to a supply rail, e.g. B. B+ or 12V power supply from the vehicle, which is a standard automotive 12 V power supply is from the lead-acid, non-traction battery of the electrified vehicle. The reference circuit 755 can also use the mass reference on the second communication channel 732 to the SAW GMI sensor 702 traverse. In one example, the copper ground plane is the control module 703 connected to the chassis reference in the vehicle. This copper ground plane of the control module is available in the reference circuit, e.g. B. when the circuit is a solid state. Another way of saying this is that the communication channel 732 is at equal potential with the ground plane of the control module that is connected to the vehicle chassis.

[0056] figure 8 shows the reference circuit 755 , to be included in the ports associated with the communication channels 731 , 732 are connected. The B+ power supply 801 enters the reference circuit 755 a, e.g. B. to the power supply circuit 802 . The power supply circuit 802 converts the approximately 12V from the vehicle from the B+ power supply 801 into an accuracy reference circuit 804 around. The accuracy reference circuit 804 outputs a precision regulated voltage (PREF) to the terminal 805 out. The PREF signal is sent to a buffer circuit 806 fed. In one example, the output is from the buffer circuit 806 to the first communication channel 731. The buffer circuit 806 is to ensure that the CS_VREF voltage is the same as the PREF voltage. The buffer circuit 806 should only drop a few millivolts from the PREF 19 , 20 to output CS_VREF of the communication channel 731 to permit. The result of the circuit in the reference circuit block 755 is that the accuracy reference voltage output CS_VREF over the first channel 731 , pointing to the input of the SAW-GMI sensor 702 is applied, the same as the accuracy reference to the 745 A / D converter in the control module 703 is.

[0057] Referring again to figure 7 contains the SAW GMI sensor 702 a SAW-GMI circuit 714 . This consists of a GMI thin film built into a SAW device and associated with the interface circuits. Interface circuits are able to translate the noise in the SAW-GMI into a simple analog signal (a scalar voltage) that can be processed by the digital processor 715 can be read. The placement of the SAW GMI sensor 702 is such that the SAW-GMI element 714 is close to a lithium ion battery cell. As further discussed herein, the degree of lithiation in the cell is closely related to the magnitude of the magnetic field that can be measured in the vicinity of the cell. GMI sensors are quite sensitive, for example with a range of ±300 µT and a sensitivity of 4 mV / µT. The built-in SAW-GMI sensor system 702converts the magnetic field into a measurable voltage (CS_AOUT) on the third communication channel 733 around. In one example, the SAW GMI sensor system 702 in such a way that when the magnetic field which the SAW-GMI element 714 traverses, ranges from -300 µT to +300 µT, the voltage of the output signal (CS_AOUT) ranges from +0.5 V to +4.5 V.

[0058] The output of the SAW GMI element 714 can be an analog voltage, that of the digital processor circuit 715 of the SAW-GMI sensor system 702 is supplied.

[0059] figure 9 shows a course 900 a transfer dependency of the magnetic field to the voltage output from the sensor subsystem 702 , which measures lithium ions at a terminal in a battery cell. The sensor subsystem 702 measures the magnetic field and uses the transmission dependency, which can be a formula or look-up table, which is in the circuitry of the sensor subsystem 702 is stored outputs a voltage signal of a digital signal that provides a voltage to the Battery Control Module (BCM) 703 represents. In one example, the magnetic field can range from approximately -300 µT to 300 µT. The output signal can range from 0.5 volts to 4.5 volts. The degree of lithiation in the battery cell is closely related to the magnitude of the magnetic field that can be measured near the cell using the sensors described herein. In the GMI sensor example, the GMI sensor is sensitive, for example with a range of ±300 µT and a sensitivity of 4 mV / µT.

[0060] The present systems are operable to wirelessly sense a condition of a battery. A method may wirelessly transmit an input signal to the battery; receiving the input signal at a passive sensor connected to the battery; outputting a response signal that changes based on a modulus of the battery; and outputting the battery condition based on the response signal.

[0061] In one example, the input signal is a magnetic field.

[0062] In one example, the input signal is an electromagnetic signal and the sensor is a surface acoustic wave sensor that detects a magnetic field at an electrode of the battery. The SAW sensor includes a temperature sensor and a magnetic field sensor.

[0063] In one example, outputting the response signal includes wirelessly outputting the response signal from the surface acoustic wave sensor to a receiver external to the battery.

[0064] In operation, surface acoustic wave (SAW) based devices, which can be configured for either wireless operation, provide a sensor platform for measuring active lithium concentration via magnetic field detection. These sensors are based on the piezoelectric effect, whereby the propagation speed of a SAW signal in a piezoelectric substrate changes in response to surface disturbances. SAW devices are sensitive to temperature, pressure, strain, fluid viscosity, and surface effects. To measure the magnetic field response for a charged / discharged cell, the surface of the SAW must be modified with a magnetic element to convert the magnetic field change into a surface perturbation. The present disclosure includes overlaying the propagation path with a magnetoresistive (MR) layer, a giant magnetoimpedance (GMI) film, or embedding a permanent magnet in a cantilever substrate structure. Among the available magnetic field sensors, the SAW-based thin-film GMI offers advantageous properties such as high-frequency sensitivity to the magnetic field, compatibility with high-frequency processes and standard microfabrication procedures, and easy incorporation into SAW devices and electronic circuits.

[0065] The systems and methods described herein can measure the temperature at and within each battery cell and the state of charge. Specifically, using smart sensor systems that can be embedded with directly measuring the physical properties or internal condition of the battery cell can provide more accurate knowledge of the battery cell's operational status. This knowledge can be used in control techniques for the battery cell and the vehicle. Using passive sensors with wireless communication enables direct measurement of battery cell properties, which was previously not possible. Because these direct measurements were not made, control algorithms made hypotheses that may be inaccurate or operate in an inefficient manner. These direct measurements can be used alone or in combination with cell voltage measurement techniques.

[0066] The sensors and tags described herein are packaged to withstand the vehicle environment. The vehicle environment includes temperature and humidity, as well as vibration associated with vehicle motion and engine vibration. The sensors and tags, when attached to or within the battery, are further packaged to withstand the -40°C to 75°C temperature range (storage: 85°C) and the potentially corrosive environment of batteries. The sensors can communicate wirelessly with other communication devices within the vehicle or with coupled components. The sensor systems described herein can observe the internal condition of the battery and use this information to determine information, e.g. B. voltage, SOC, local temperature, state of health, etc. These sensor systems are believed to be low maintenance compared to current sensors as they do not have batteries or other power sources that need to be replaced or topped up or connected. These sensors are small in size, on the order of a grain of rice in some examples, thereby ensuring unobtrusive deployment on or within the battery. It is anticipated that these sensors will facilitate the use of multiple sensors to form a distributed wireless sensor network as well as maintain electromagnetic compliance with the vehicle as these devices are low power devices with small electromagnetic fields.

[0067] This disclosure uses the term chips, which can be circuits, integrated circuits, microelectromechanical systems (MEMS), or combinations thereof, that can perform the functions described herein. The chips may need to encounter extreme environmental conditions of internal battery conditions, battery packaging, or being mounted in a vehicle exposed to high temperatures and freezing and remain operational in various examples.

[0068] The present disclosure, in various embodiments, addresses the needs of electrified vehicles having a high voltage battery used as a traction battery. The controls for electrified vehicles have two parameters that need to be estimated, viz. H. the state of charge (SOC) and capacity of each cell. Previous methods do not measure SOC and capacitance directly, but instead estimate them based on voltage, current, and temperature inputs. There are a large number of techniques as to how to estimate SOC and capacity. It should be noted that there is no simple relationship between cell voltage, current, temperature and SOC. The voltage of a cell is a displacement function, especially with regard to the history of the current in the recent past. To add complexity, the cell voltage that can be measured is actually the difference between two voltages, that of the reactions at each of the two electrodes in the cell. Even quiescent open circuit voltage (OCV), the previous best voltage measurement, is not perfect for state of charge correlations for these battery chemistries where there is a good relationship between OCV and SOC. Not only does the battery need to be dormant for a period of time, the SOC / OCV relationship itself changes over time under certain circumstances.

[0069] Knowing the capacity of a battery is important for applications such as a battery electric vehicle, where the remaining range (distance to empty) needs to be estimated. Although the capacity of a new battery is known, it will change over time, often significantly. Previous methods required that capacity be calculated as the ratio of charge used to the difference in states of charge over the range, as shown in the equation below. This is subject to significant errors, that of current binding and that of initial and final states of charge, so care must be taken when calculating capacity. An example of estimation can be found in US Patent No. 8,751,086. Q = ∫ I d t S O C f − S O C i

[0070] The presently described methods and systems provide direct measurement of the state of charge and / or capacity of a lithium cell of the type used in electrified vehicles. This can provide a non-invasive method that directly measures the concentration of active lithium in positive electrodes. The present disclosure can be free from cumulative errors present in the SOC calculation of the art, e.g. B. compared to the Coulomb count. In operation, the present methods and systems can be used as an inexpensive laboratory tool to monitor cell performance as seen in actual use, i. H. a "reference electrode" that is not involved in cell reactions. The sensor device can be designed to measure both the temperature and the concentration of active lithium. Since the device can be designed to communicate in a wireless manner, this will eliminate the NTC thermistor and associated wires used in the battery pack today to measure temperature. You will see that the SOC is not only determined by the integration of electricity.

[0071] While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. The terms used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the invention. In addition, the features of different implementation embodiments can be combined with one another to form further embodiments of the invention. QUOTES INCLUDED IN DESCRIPTION

[0000] This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited

[0000] US8751086

[0069]

Claims

[1] Vehicle, comprising: an electric motor; a battery to store electrical energy for the electric motor; and an acoustic surface wave sensor to wirelessly detect a magnetic field of the battery and the battery temperature, wherein the sensor includes a reactive magnetic field device to change a surface wave in response to the magnetic field depending on the lithiation of an electrode of the battery. [2] Vehicle according to claim 1, wherein the acoustic surface wave sensor includes a radio frequency identification tag. [3] Vehicle according to claim 1, further comprising a control circuit to control the electric motor and the battery on the basis of an output signal from the acoustic surface wave sensor. [4] Vehicle according to claim 3, wherein the control circuit determines a battery state from an output signal of the acoustic surface wave sensor. [5] Vehicle according to claim 4, further comprising a circuit to determine the state of charge (SOC) or state of health (SOH) of the magnetic field as detected by the acoustic surface wave sensor. [6] Vehicle according to claim 1, wherein the acoustic surface wave sensor is embedded in a housing of the battery and communicates wirelessly with the control circuit of the electric motor. [7] Vehicle according to claim 1, wherein the acoustic surface wave sensor includes a plurality of sound reflectors and converts an input signal into an acoustic surface wave signal which is reflected by the reflectors to generate a response signal and is modified by the reactive magnetic field device. [8] Vehicle according to claim 7, wherein the reactive magnetic field device includes a giant magnetoimpedance (GMI) thin film. [9] Vehicle according to claim 8, further comprising a mechanical damper on the surface acoustic wave (SAW) substrate adjacent to the GMI thin film and the matching circuit which electrically connects the GMI thin film to at least one of the plurality of sound reflectors. [10] Vehicle according to claim 9, wherein at least one of the plurality of sound reflectors includes an interlocking reflector with a cone having a thickness of λ / 8 relative to a signal on the SAW substrate. [11] Vehicle according to claim 8, wherein the acoustic surface wave sensor includes a circuit to convert the detected magnetic field into an output voltage. [12] Battery monitoring system, comprising: an acoustic surface wave sensor to wirelessly detect battery status, which also includes a magnetic field detection device to modify a SAW signal based on a magnetic field at a battery electrode, a temperature sensor to detect the temperature of a battery, and a transducer to wirelessly output a signal that includes the temperature and battery status; and a control circuit to convert the detected magnetic field into an output voltage signal. [13] Battery monitoring system according to claim 12, wherein the acoustic surface wave sensor is embedded in a housing of the battery. [14] Battery monitoring system, comprising: an acoustic surface wave sensor to wirelessly detect battery status, which also includes a magnetic field detection device to modify a SAW signal based on a magnetic field at a battery electrode, a temperature sensor to detect the temperature of a battery, and a transducer to wirelessly output a signal that includes the temperature and battery status; and a control circuit to convert the detected magnetic field into an output voltage signal, wherein the acoustic surface wave sensor includes a plurality of sound reflectors and the magnetic field detection device includes a giant magnetoimpedance (GMI) thin film connected to at least one of the sound reflectors. [15] Battery monitoring system according to claim 14, wherein the magnetic field detection device includes a mechanical damper adjacent to one of the sound reflectors and the GMI thin film, wherein the magnetic field detection device includes an matching circuit connected to the sound reflector and the GMI thin film, wherein the transducer includes a conversion circuit to convert the detected magnetic field into an output signal to be wirelessly transmitted from the acoustic surface wave sensor to an external circuit on a vehicle, and wherein the at least one of the plurality of sound reflectors includes an interlocking reflector with a cone having a thickness of λ / 8 relative to a signal on a substrate of the acoustic surface wave sensor.

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