NMR measuring head for carrying out in-operando measurements on a battery

Abstract

The invention relates to an NMR measuring head (2) for carrying out NMR measurements on a battery (1), comprising i) a measuring station (15) for a battery (1), comprising a first contacting element (K1) and a second contacting element (K2) for a first electrode (E1) and a second electrode (E2) of the battery (1), ii) a tuning capacitor (30), iii) a first HF connection (H1) and a second HF connection (H2) for an NMR console (6), the contacting elements (K1, K2) being connected so as to conduct an HF current via the tuning capacitor (30) such that an HF resonant circuit (3) can be set up using a battery (1) to be placed at the measuring station (15), and the first HF connection (H1) being connected to the first contacting element (K1) so as to conduct an HF current and the second HF connection (H2) being connected to the second contacting element (K2) so as to conduct an HF current, iv) a first DC connection (D1) and a second DC connection (D2) for a DC current element (4), and v) at least one first block element (B1) which is permeable to DC current and blocks HF current at least in the range of a provided resonant frequency REF of the HF resonant circuit (3), the first DC connection (D1) being conductively connected to the first contacting element (K1) via the first block element (B1), and the second DC connection (D2) being connected to the second contacting element (K2) so as to conduct a DC current. The NMR measuring head allows in-operando NMR measurements to be simply carried out on a battery with a high signal strength.

Description

[0001] SP14057PCT P 10.12.2025

[0002] Applicant:

[0003] Bruker Switzerland AG Industriestrasse 26 8117 Fällanden

[0004] Switzerland

[0005] Representative:

[0006] KOHLER. SCHMID FURNITURE

[0007] patent attorneys

[0008] limited liability partnership

[0009] Gropiusplatz 10 70563 Stuttgart Germany

[0010] NMR measuring head for in operando measurements on a battery

[0011] The invention relates to an NMR measuring head for performing NMR measurements on a battery.

[0012] Such an NMR measuring head is known, for example, from US 11 215 686 B2.

[0013] Nuclear magnetic resonance (NMR) spectroscopy can be used to analyze the chemical composition of samples. For this purpose, a sample is exposed to a homogeneous static magnetic field (“B0 field”, constant over time) of a background magnet (often a superconducting background magnet), and radio frequency (RF) pulses (“Bl field”, time-varying) are directed perpendicular to the static magnetic field into the sample and interact with the nuclear spins of the atoms and molecules in the sample. A resulting RF signal from the sample is measured, and from this, the chemical composition is determined.

[0014] Bruker Switzerland AG 10.12.2025 SP14057PCT The composition of the sample can be inferred from the measurement result.

[0015] In a typical MMR setup used in chemical analysis, the sample is positioned in an NMR probe head (also called an NM probe head) which contains an RF resonator or an RF coil, with the RF resonator or coil surrounding the sample. The NMR probe head protrudes into a magnetic bore of the background magnet.

[0016] In recent years, the importance of technical applications requiring batteries has increased. Here, "batteries" encompasses all types of electrochemically based electrical energy storage devices; batteries include both non-rechargeable batteries (also known as primary batteries) and rechargeable batteries (also known as accumulators or secondary batteries). Technical applications requiring batteries include, for example, watches (including smartwatches), hearing aids, flashlights, mobile phones and tablets, and even motor vehicles.

[0017] For battery research and development, including the optimization of energy density, charging efficiency, and battery lifespan, investigating the electrochemical processes within batteries is of great interest. Particular attention is paid to the electrochemical processes during charging and discharging. The information content of solid-state nanometers is very high compared to other spectroscopic techniques, so that in many cases it is not necessary to combine them with other analytical methods.

[0018] Batteries are typically housed in metallic casings. If such a battery is placed in an RF resonator or coil, the RF pulses and signals cannot penetrate the metallic casing, or only to a very limited extent. Consequently, only very low signal strengths can be achieved in an NMR measurement.

[0019] Bruker Switzerland AG 10.12.2025 SP14057PCT To circumvent this problem, it has become known to arrange the internal electrochemical assembly of the battery under investigation in an electromagnetically transparent container (usually made of plastic). The corresponding plastic battery cell can then be placed inside an RF resonator or an RF coil. The company ePROBE GmbH, Erfurt, Germany, offers corresponding NMR probe heads and associated plastic containers commercially; see https: / / eprobe.tech / products / probes (accessed on 6.12.2024) and https: / / eprobe.tech / products / cells (accessed on 6.12.2024). The ePROBE probe head comprises a solenoid coil as the RF coil, into which a cylindrical plastic container is inserted, which in turn contains the electrochemical assembly under investigation.While this approach allows for highly efficient NMR measurements on the electrochemical setup, and also enables in-operando investigations (i.e., during charging and discharging), the electrochemical processes in the plastic battery cell are not identical to those in the original battery, which has a metallic casing.

[0020] In US 11 215 686 B2, also published as US 2021 / 0318401 Al, it is proposed to arrange a coin cell with a metallic casing inside a hairpin resonator, with the high-frequency oscillating magnetic fields aligned tangentially to the coin cell electrodes. The coin cell is electrically isolated from the hairpin resonator. In a variant for operando NMR, it is proposed to connect the battery cell electrodes to DC wire conductors for charging and discharging, whereby the DC wire conductors do not touch the resonator and the DC connections are equipped with RF chokes. With this setup, some penetration of the RF fields into the coin cell through its insulation gap is achieved, but the NMR performance is still relatively low. A similar approach is also described by Brennan J. Walder et al. in "NMR spectroscopy of coin cell batteries with metal casing" Sei. Adv. 2021; 7: e- abg8298, September 10, 2021.The only difference compared to commercially available button cells and standard button cells used in battery research is that the casing is made of titanium.

[0021] Bruker Switzerland AG 10.12.2025 SP14057PCT In S. Benders et al., “Nuclear magnetic resonance spectroscopy of rechargeable pouch cell batteries: beating the skin depth by excitation and detection via the casing”, Sei. Rep. (2020) 10: 13781, pp. 1-7, it is proposed to apply a copper tape to each of the two outer surfaces of a pouch cell and connect them to the RF terminals of an NMR spectrometer. The two copper tapes are also connected to each other via a tuning capacitor, thus establishing an RF resonant circuit. A matching capacitor is connected in series with the RF resonant circuit. The electrode terminals of the pouch cell are galvanically isolated from the copper tapes. Before integrating the pouch cell into the RF resonant circuit, several charge / discharge cycles were performed at 300 mA. A similar procedure is described in US 2022 / 0003824 Al.From DE 10 2022 131 403 Al it has become known to integrate a battery to be measured directly into the resonant circuit of an NMR probe head.

[0022] Furthermore, US patent 2018 / 0053973 Al has disclosed the integration of a stripline resonator into a battery or fuel cell. This enables NMR measurements with a high signal-to-noise ratio. However, this approach does not allow for direct measurement of an original battery. Additionally, the stripline resonator can alter the electrochemical processes within the battery.

[0023] The object of the invention is to provide an NMR measuring head with which NMR measurements on a battery with a high signal strength can be easily performed in operando.

[0024] This problem is solved according to the invention by an NMR measuring head for carrying out NMR measurements on a battery, comprising

[0025] Bruker Switzerland AG 10.12.2025 SP14057PCT i) a measuring station for a battery, comprising a first contact element for a first electrode of the battery and a second contact element for a second electrode of the battery, ii) a tuning capacitor, and iii) a first RF connection and a second RF connection for an NMR console, wherein the first contact element and the second contact element are conductively connected for RF current via the tuning capacitor, so that an RF resonant circuit can be set up with a battery to be arranged at the measuring station, and wherein the first RF connection is conductively connected to the first contact element for RF current and the second RF connection is conductively connected to the second contact element for RF current, iv) a first DC connection and a second DC connection for a DC current element, and v) at least a first block element,which is permeable to DC current and blocking to RF current at least in the range of a specified resonant frequency REF of the RF resonant circuit, wherein the first DC terminal is conductively connected to the first contacting element via the first blocking element, and the second DC terminal is conductively connected to the second contacting element for DC current.

[0026] The invention provides for the establishment of an RF resonant circuit into which the battery to be measured is directly integrated. For this purpose, the two contact elements in the NMR measuring head, which contact the battery's electrodes when the battery is inserted, are conductively connected to each other via the tuning capacitance for RF current. The NMR measurement can then be performed in an NMR spectrometer using this RF resonant circuit.

[0027] The RF connections, to which the NMR console of the NMR spectrometer is connected, are conductively connected to the contact elements for RF current. This makes the battery electrodes accessible to RF pulses, and RF signals from the battery can be read out.

[0028] Bruker Switzerland AG 10.12.2025 SP14057PCT The battery can be considered a resonator. The opposing electrodes with the intervening electrolyte layer represent a capacitance, whereby the electrolyte layer contributes to relatively high losses in the RF range. In addition, the metallic elements of the battery provide inductance and also ohmic resistance. The battery's resonant frequency depends strongly on its construction and size and is usually in the range of 10 MHz to 10 GHz.

[0029] By connecting the electrodes or contact elements via the tuning capacitor, the battery's resonant frequency can be changed and, in particular, adjusted to a measurement frequency of the NM spectrometer. Note that, if desired, additional electrical elements (impedance elements) can be connected in series with the tuning capacitor in the electrical connection of the electrodes. The tuning capacitor can be a single component or multiple components, for example, with a first partial tuning capacitor and a second partial tuning capacitor in series. In practice, the tuning capacitor or partial tuning capacitors can be implemented by a single capacitor or several capacitors connected in parallel. The tuning capacitor blocks DC current in the electrode connection, thus preventing a DC short circuit of the battery electrodes via the RF side.

[0030] To enable NMR measurements during operation (i.e., NMR measurements while charging or discharging the battery), the NMR probe head is provided with DC connections to a DC current element. At least the first DC connection is conductively connected to the first contact element via a first block element. This first block element is permeable to DC current but blocks RF current at least within a predetermined frequency range, corresponding to the resonant frequency REF of the RF resonant circuit. The second DC connection is conductively connected to the second contact element for DC current. If desired, the second DC connection can be connected to the second contact element via a second block element, which is permeable to DC current but blocks RF current at least within the resonant frequency REF of the RF resonant circuit (see below).

[0031] Bruker Switzerland AG 10.12.2025 SP14057PCT The second block element is not required if the second contact element is grounded; in this case, the second DC terminal can be directly electrically connected to the second contact element.

[0032] The DC current element, connected to the DC terminals, allows the battery to be charged or discharged during an ongoing NMR measurement. The associated DC current is not affected by the blocking element(s) (apart from the inherent series resistance of each blocking element). However, the blocking element(s) filter out (block) RF currents at least at and near the resonant frequency of the RF resonant circuit or at or near the measurement frequency of the NMR measurement. The blocking element(s) thus ensures that the DC current element does not affect the RF resonant circuit and, in particular, does not cause any interference (especially no additional noise) in the NMR measurement.Furthermore, it is also ensured that the DC current element is not affected or damaged by RF currents from the NMR measurement (especially when RF pulses are injected into the battery).

[0033] The batteries to be measured can be of conventional design within the scope of the invention, in particular with metallic housings. In particular, it is not necessary to insert resonators into the battery.

[0034] Within the scope of the invention, a high NMR signal strength can be achieved because RF pulses can be introduced directly into the interior of the battery via the electrically contacted electrodes of the battery itself, and RF signals from the battery can be registered with the battery's electrodes themselves. No penetration of external electromagnetic fields into the battery through a housing is necessary. Accordingly, within the scope of the invention, the housing of the battery under investigation can be metallic. Preferably, the metallic electrodes of the battery substantially completely overlap the cross-section of the battery from opposite sides.

[0035] Bruker Switzerland AG 10.12.2025 SP14057PCT According to the invention, the two contact elements (or the two battery electrodes) are electrically connected to both the NMR console (or the RF source for the NMR measurement) via the RF connections and to the DC current element via the DC connections. RF current is blocked relative to the DC current element by the at least one blocking element. In addition, DC current is typically also blocked relative to the RF source by a blocking capacitor (see below). According to the invention, a DC current and an RF current can be applied simultaneously to the battery electrodes, and NMR measurements can therefore be performed concurrently.

[0036] If desired, the NM measurement frequency and, consequently, the resonant frequency of the RF resonant circuit can also be variable, for example, via a variable tuning capacitance. The invention can also be used in a similar manner for multi-core circuits with multiple resonant frequencies REFi (where i is the index of the cores under investigation). For this purpose, separate RF connections can optionally be provided for the different measurement frequencies. The blocking element(s) then block RF current at least at each of the resonant frequencies REFi.

[0037] Preferred embodiments of the invention

[0038] In a preferred embodiment, the measuring station is configured for a battery designed as a button cell. Button cells allow for the simple adjustment of the self-resonance (in the fundamental mode) to the measurement frequency of the NMR measurement using the tuning capacitance. Since the self-resonance of this battery type is higher than the usual NMR measurement frequencies, and no higher self-resonance mode with at least one current within the battery needs to be used for the measurement, homogeneous current distributions across the conductor elements within the battery can be achieved. However, it is also possible to use the invention with other battery types, in particular pouch cells or cylindrical cells; optionally, a higher self-resonance mode can then be tuned to the measurement frequency using the tuning capacitance, although this may compromise the field homogeneity of the generated Bl-

[0039] Bruker Switzerland AG 10.12.2025 SP14057PCT Fields suffers.

[0040] In one embodiment, the second RF connection is particularly preferred, as it is connected to ground. This simplifies the overall design of the NMR probe.

[0041] In a preferred embodiment, the tuning capacitor is configured with a first partial tuning capacitor and a second partial tuning capacitor, wherein the first partial tuning capacitor and the second partial tuning capacitor are connected in series in the RF resonant circuit, and a center tap between the first partial tuning capacitor and the second partial tuning capacitor is connected to ground. This simplifies the process of maintaining (approximate) electrical symmetry in the RF resonant circuit (i.e., symmetrical potentials between the electrodes or between the contact elements during measurement operation) and thus minimizes power losses during the transmission of RF pulses in the battery and received noise from the battery.

[0042] An advantageous embodiment is one in which the second contact element is connected to ground. In this case, a second block element is generally unnecessary, and a particularly simple electrical design of the NMR measuring head is achieved.

[0043] In another advantageous embodiment, the NMR measuring head further comprises

[0044] - a second blocking element, which is permeable to DC current and blocking to RF current at least in the region of the intended resonant frequency REF of the RF resonant circuit, wherein the second DC connection is conductively connected to the second contacting element via the second blocking element. In this design, the DC current element can be "floating" and does not need to be connected to ground, i.e., DC-

[0045] Bruker Switzerland AG 10.12.2025 SP14057PCT Power can be connected differentially. This can partially suppress external noise that couples in in common-mode mode.

[0046] A preferred embodiment includes one or more impedance matching elements in the NMR measuring head. This allows the NMR measuring head to be matched to the impedance of the NMR transmitting and receiving electronics in the NMR console. The entirety of the impedance matching elements is also referred to as an impedance matching network. The impedance matching element(s) can, for example, include capacitors, inductors, transformers, and / or coaxial cables of variable impedance and length.

[0047] A preferred embodiment includes a further development in which one of the RF connections, particularly the first RF connection, is connected to its associated contact element via a matching capacitor. The matching capacitor can then serve a dual purpose: firstly, it contributes to impedance matching, and secondly, it blocks DC current from the battery or DC current source, thus preventing the NMR measurement electronics in the NMR console from being affected or damaged by DC current or the resulting voltage.

[0048] A further preferred design provides that the tuning capacitance and the impedance matching element(s) are connected in such a way that at least approximately symmetrical potentials are maintained at the two contact elements during measurement operation, in particular where the first RF connection is conductively connected to the first contact element for RF current via a matching capacitance, and the second contact element is conductively connected to ground for RF current via a balancing capacitance, and the matching capacitance and the balancing capacitance have at least approximately the same capacitance value. Such an approximately symmetrical design of the impedance matching network minimizes power losses and interference.

[0049] Bruker Switzerland AG 10.12.2025 SP14057PCT. Losses in the battery, which provides the relevant inductance for losses in the RF resonant circuit and is connected to the contact elements, are proportional to the square of the electric field strength. By using an (approximately) symmetrical connection, the loss-causing electric field strength can be (approximately) halved compared to a completely asymmetrical connection (which is achieved with one electrode of the battery connected to ground). Remaining asymmetries typically result from matching circuit sides in the NMR probe to ground and 50 ohms. The design with a matching capacitance and a balancing capacitance is relatively easy to implement and allows for a "floating" DC current element (without contact to ground).Approximately equal capacitance values ​​for matching and balancing capacitances are typically achieved when the capacitance values ​​differ by a maximum of 20%, relative to the smaller capacitance value. In the case of high resonator Q factors, the differences can be significantly smaller, for example, less than 2%, relative to the smaller capacitance value. The same applies to other impedance matching configurations.Another impedance matching configuration to obtain approximately symmetrical potentials at the contact elements involves designing the tuning capacitor with a first partial tuning capacitor and a second partial tuning capacitor. The first and second partial tuning capacitors are connected in series in the RF resonant circuit, and a center tap between the first and second partial tuning capacitors is connected to ground. The first and second partial tuning capacitors have approximately equal capacitance values ​​(see also above). This configuration with a first and second partial tuning capacitor is also relatively easy to implement and allows for a "floating" DC current element (without contact to ground).

[0050] A preferred embodiment is one in which at least one of the RF connections is connected to its associated contact element via a DC blocking capacitor.

[0051] Bruker Switzerland AG 10.12.2025 SP14057PCT is connected. The DC blocking capacitor blocks direct current. This ensures that no direct current (from the battery or the DC power element) is fed into an NMR console connected to the RF terminals or any RF source located there. The DC blocking capacitor can be part of an impedance matching network (see above).

[0052] In a preferred embodiment, each block element is configured as a low-pass filter. This design achieves a high attenuation effect within a defined frequency range. The low-pass filter is typically configured for defined impedances at the filter's input / output.

[0053] A preferred embodiment incorporates a low-pass filter inductor. This is particularly easy to implement. The (serial) low-pass filter inductor can prevent a short circuit of the RF resonant circuit to ground when a leakage capacitance is used. In particular, the low-pass filter can consist solely of the low-pass filter inductor.

[0054] In another advantageous variant of the above refinement, the inductance value LTPF of the low-pass filter inductance is greater than the inductance value Lßatt of the battery in the RF resonant circuit, specifically where LTPF > 1 nH, or 1 nH < LTPF < 50 µH, or 100 nH < LTPF < 25 µH. If LTPF > Lßatt, good filtering performance can generally be achieved in the relevant frequency range. High LTPF values ​​allow for very efficient blocking of high frequencies. Note that real components for implementing high inductances often exhibit significant parasitic capacitances, which should be taken into account when designing the circuit, for example, by using an inductor whose resonant frequency (including its parasitic capacitance and, if applicable, its ohmic resistance) is higher than the resonant frequency REF of the RF resonant circuit.

[0055] Bruker Switzerland AG 10.12.2025 SP14057PCT A further preferred variant provides that a leakage capacitance, connected to ground, is connected between each block element and its associated DC terminal, and that the respective series resonant frequency, which belongs to a series connection of the low-pass filtered inductance of the respective block element with the associated leakage capacitance, is significantly lower than the intended resonant frequency REF of the RF resonant circuit, in particular by at least a factor of 5, preferably by at least a factor of 10, and most preferably by at least a factor of 50. Waves (RF current) that still pass through the RF block (block element) can thus be routed to ground, and an improved blocking effect is achieved. This configuration is non-resonant and therefore broadband.Note that this setup typically uses relatively large low-pass filter inductances, e.g. with LTPF > 1 nH or even LTPF — 100 nH.

[0056] A preferred variant provides that a leakage capacitance, connected to ground, is connected between each block element and its associated DC terminal, and that the respective series resonant frequency, corresponding to a series connection of the low-pass filter inductance of the respective block element with the associated leakage capacitance, corresponds at least approximately to the intended resonant frequency REF of the RF resonant circuit. With this configuration, a high blocking effect can be achieved at a specific frequency, so that the resonant frequency REF, in particular, can be efficiently blocked.The blocking effect for the RF current is achieved primarily through resonance of the resonant circuit (consisting of the series connection of the low-pass inductor and the leakage capacitance, connected to ground), and only to a lesser extent through the low-pass filter effect of the low-pass filter inductor itself; the leakage capacitance can therefore also be considered functionally as part of the blocking element. In this sub-variant, low-pass filter inductors with smaller inductance values ​​can also be used, especially smaller than in the one in question.

[0057] Bruker Switzerland AG 10.12.2025 SP14057PCT of the previous sub-variant, e.g., with LTPF < 1 nH. Losses in the filter are adjustable via the inductance value of the low-pass filter inductor. Note that in the case of two block elements, their series resonant frequencies (SRI, SR2) are typically chosen with a certain deviation from each other to avoid resonance splitting. In this case, for example, one series resonant frequency is at REF, and the other series resonant frequency deviates slightly from REF. Typically, the series resonant frequencies (SRI, SR2) each deviate by a maximum of 10% from REF (relative to REF).

[0058] An advantageous embodiment is one in which each blocking element is designed as a resonant circuit, with the resonant circuit blocking in the region of the intended resonant frequency REF of the RF resonant circuit. This design allows independent adjustment of the circuit's symmetry, particularly via an impedance matching element (balancing impedance ZS), which is connected to ground from the second contacting element (optionally via a second tuning capacitor). The resonant circuit is generally formed by a parallel resonant circuit consisting of a resonant circuit inductor and a resonant circuit capacitance. The resonant circuit inductance Lresonant is typically chosen to be larger than the inductance Lresonant. Ba tt of the battery, in order to maintain a low impact on the efficiency of the resonant circuit at REF while ensuring good blocking effect of the filter.

[0059] A preferred embodiment of the NMR measuring head provides that a battery holder is available with which the battery can be fixed to the measuring station, so that when the battery is arranged in the battery holder, the first contacting element contacts the first electrode of the battery and the second contacting element contacts the second electrode of the battery, in particular wherein the battery can be elastically clamped in the battery holder by the first contacting element and / or the second contacting element, so that the first contacting element and the second contacting element are separated from each other

[0060] Bruker Switzerland AG 10.12.2025 SP14057PCT are galvanically isolated, and that the first contacting element and the second contacting element are connected to each other by at least one capacitor.

[0061] The battery holder facilitates handling the battery during measurement and replacement in the NMR probe. Furthermore, this design allows for easy adjustment of the tuning capacity.

[0062] An advantageous further development of this embodiment involves connecting the first and second contact elements to each other via two capacitors, particularly on opposite sides of the battery holder. This allows for a particularly homogeneous RF field distribution within the battery.

[0063] The present invention also includes an NMR spectrometer system comprising

[0064] - an NMR measuring head according to the invention, as described above,

[0065] - an NMR console connected to the RF ports,

[0066] - a DC current element that is connected to the DC terminals,

[0067] - one or more control units for the NMR console and the DC current element, in particular comprising a control PC,

[0068] - and a magnet for generating a static magnetic field at the measuring station for the battery, in particular wherein the magnet comprises a shim system. With the NMR spectrometer system according to the invention, NMR measurements can be performed on a battery at the measuring station of the NMR measuring head in operando. An NMR measurement can therefore take place simultaneously with charging or discharging the battery. The NMR measurements are easy to perform, and a high signal strength or a high signal-to-noise ratio can be achieved. The NMR measurements can provide spectrometric information with which the electrochemical processes in the battery can be elucidated.

[0069] Bruker Switzerland AG 10.12.2025 SP14057PCT In a preferred embodiment of the NMR spectrometer system according to the invention, the DC current element is a DC charger or a DC discharger. With a DC charger or DC discharger, electrical energy (corresponding to a specific current) can be supplied to or withdrawn from the battery in a controlled and defined manner. Preferably, the current and / or voltage during charging / discharging are flexibly adjustable electronically. Alternatively, a regulated or unregulated electrical load can simply be connected for discharging.

[0070] The present invention further encompasses an NMR measurement setup comprising an NMR spectrometer system according to the invention as described above and a battery arranged at the measurement station for the battery, wherein a first electrode of the battery is contacted with the first contact element, and a second electrode of the battery is contacted with the second contact element. The measurement setup allows for the simple investigation of the electrochemical behavior of the battery during charging and discharging using high-signal NMR measurements. The battery can be rechargeable or non-rechargeable (in the latter case, only discharge is possible during NMR measurement). The battery can, in particular, have a metallic housing. Preferably, the battery housing is made of a non-magnetic material, especially preferably a non-magnetic metallic material (e.g.,(made of titanium), since a magnetic casing can impair the homogeneity of the static magnetic field during an NMR measurement. Note that, within the scope of the invention, the non-magnetic material of the battery casing can be selected such that no significant electrochemical differences arise compared to a mass-produced battery (e.g., with a steel casing), thus enabling the creation of near-series prototypes for battery research, which can then be measured according to the invention. Apart from the casing material, the battery to be measured requires no special preparation (such as electrodes arranged inside the battery); rather, a conventional battery design, corresponding to a commercially available battery, can be used within the scope of the invention.

[0071] Bruker Switzerland AG 10.12.2025 SP14057PCT Finally, the invention also includes the use of an NMR measurement arrangement according to the invention, described above, wherein at the same time

[0072] - the battery is charged or discharged using the DC current element,

[0073] - and an NMR measurement is performed on the battery using the NMR console and the NMR measuring head. This allows high-quality information about the electrochemical behavior of the battery to be easily obtained directly during the charging or discharging process.

[0074] Further advantages of the invention will become apparent from the description and the drawing. Likewise, the features mentioned above and those described in more detail below can each be used individually or in any combination according to the invention. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples for illustrating the invention.

[0075] Detailed description of the invention and drawing

[0076] Fig. 1 schematically shows a simple equivalent circuit diagram of a battery, for measurement within the scope of the invention;

[0077] Fig. 2 schematically shows a circuit diagram of a first, simple embodiment of an NMR measuring head according to the invention, wherein the second RF connection and the second contacting element are connected to ground;

[0078] Fig. 3 schematically shows a circuit diagram of a further embodiment of an NMR measuring head according to the invention, with a matching capacity;

[0079] Fig. 4 schematically shows a circuit diagram of a further embodiment of an NMR measuring head according to the invention, with a matching capacitance and a matching inductance;

[0080] Bruker Switzerland AG 10.12.2025 SP14057PCT Fig. 5 schematically shows a circuit diagram of a further embodiment of an NMR measuring head according to the invention, with a general impedance matching network;

[0081] Fig. 6 schematically shows a circuit diagram of a further embodiment of an NM measuring head according to the invention, with two block elements and a symmetrical impedance matching network;

[0082] Fig. 7 schematically shows a circuit diagram of a first sub-variant of the embodiment of Fig. 6, wherein the block elements are designed with low-pass filter inductors;

[0083] Fig. 8 schematically shows a circuit diagram of a second sub-variant of the embodiment of Fig. 6, wherein leakage capacitances are connected between the low-pass filter inductors and the DC terminals;

[0084] Fig. 9 schematically shows a circuit diagram of a third sub-variant of the embodiment of Fig. 6, wherein the block elements are designed as blocking circuits;

[0085] Fig. 10 shows a circuit diagram of a further embodiment of an NM measuring head according to the invention, with two block elements and a two-part tuning capacitor with a center tap that is connected to ground;

[0086] Fig. 11 shows a schematic perspective view of an exemplary battery holder for the invention;

[0087] Fig. 12 shows a schematic perspective view of an exemplary embodiment of an NMR measuring system according to the invention.

[0088] Bruker Switzerland AG 10.12.2025 SP14057PCT Figure 1 shows a simple equivalent circuit diagram of a battery 1, which is to be subjected to an NMR measurement within the scope of the invention. The battery 1 can, for example, be constructed as a button cell.

[0089] Battery 1 has a first electrode El and a second electrode E2. In the case of a button cell, for example, the positive electrode of battery 1 can be designed as a metallic cup, and the negative electrode as a metallic cap. The two electrodes El and E2 do not touch inside battery 1 but are electrically separated by an insulating layer (not shown in the circuit diagram). The interior of battery 1 contains an electrochemical structure, typically based on an electrolyte, which is responsible for storing electrical energy. The two electrodes are connected to each other within the battery via this electrochemical structure. In the equivalent circuit diagram, Csatt represents the capacitance between electrodes El and E2 across the electrolyte or an associated electrolyte layer.eiectroiyte represents the value of the ohmic resistance (as a measure of resistive losses) across the electrolyte layer. Finally, L represents... Ba tt the value of the inductance of the battery, determined mainly by its metallic elements (especially the electrodes), and metai the value of the ohmic resistance (as a measure of resistive losses) across the metallic elements of battery 1.

[0090] Battery 1 thus represents a simple RF resonator. The self-resonance of battery 1 depends on its design and size. By adding capacity, the self-resonance of battery 1 (or the resulting overall circuit) can be tuned to a frequency to be measured (see, for example, Fig. 2).

[0091] Fig. 2 schematically shows a circuit diagram of an NMR measuring head 2 (also called NMR probe head) for the invention in a first, simple embodiment.

[0092] Bruker Switzerland AG 10.12.2025 SP14057PCT Battery 1 contacts a first contact element Kl of the NMR measuring head 2 with its first electrode El, and a second contact element K2 with its second electrode E2. The contact elements Kl and K2 are electrically connected to each other via a tuning capacitance 30 (with capacitance value CT). The contact elements Kl and K2 are thus conductively connected to each other for RF current via the tuning capacitance 30; however, DC current is blocked in this current path by the tuning capacitance 30.

[0093] An RF resonant circuit 3 (shown with a dashed outline) is established by the battery 1 and the tuning capacitance 30. The resonant frequency REF of the RF resonant circuit 3 is adjusted by means of the tuning capacitance 30 so that it corresponds to a desired frequency (irradiated by an NMR console) for the NMR measurement. The tuning capacitance 30 can be adjustable, i.e., have an adjustable capacitance value CT, particularly to adapt to different types of batteries 1 being measured.

[0094] A first RF connection Hl is directly connected to the first contact element Kl (and thus to the first electrode El). A second RF connection H2 is also directly connected to the second contact element K2. Both the second RF connection H2 and the second contact element K2 are grounded.

[0095] Via the RF connections H1, H2, an NMR measurement can be performed on battery 1 using the connected NMR console (not shown, but see, for example, Fig. 3) of an NMR spectrometer, with battery 1 being directly integrated into the RF resonant circuit 3. Note that the RF electronics in the connected NMR console should be designed such that they do not establish a (parallel) current path for DC current (unless a blockage for DC current is already ensured by other components in the NMR sample head 2, e.g., by a series DC blocking capacitor, see, for example, Fig. 3). Furthermore, the RF electronics in the connected NMR console should be protected against voltages from the charging management system (i.e., from the DC current element 4).

[0096] Bruker Switzerland AG 10.12.2025 SP14057PCT be protected (unless protection already exists through other components in the NMR probe head 2).

[0097] A first block element Bl is connected to the first contact element Kl. The first contact element Kl is connected to a first DC terminal D1 via the first block element Bl. A DC current element 4 is connected to this first DC terminal D1 and to another DC terminal D2. The DC current element 4 is a DC charger 5; alternatively, the DC current element 4 can also be a DC discharger (the latter not shown in detail). The first block element Bl is conductive for DC current. However, the first block element Bl blocks RF current, at least in the region of the resonant frequency REF of the RF resonant circuit 3. In general, the first block element Bl attenuates RF current at frequency REF by at least a factor of 10, preferably at least a factor of 100, and most preferably at least a factor of 1000. The second DC terminal D2 is connected to ground.The second DC terminal D2 is therefore also connected to the second contact element K2 (and thus to the second electrode E2) via ground, in particular conductive for DC current.

[0098] The DC current element 4 can be integrated into the NMR measuring head 2, or it can be separate from the NMR measuring head 2. The DC terminals D1 and D2 connected to the DC current element 4 are part of the NMR measuring head 2.

[0099] Due to the first blocking element Bl, no high-frequency interference from the DC terminals D1, D2, or from the DC current element 4 can impair the NMR measurement (which takes place at the resonant frequency REF of the RF resonant circuit 3). Conversely, no RF current from the NMR measurement can impair or damage the DC current element 4, and the efficiency in both transmission and reception can be optimized. The at least one first blocking element Bl prevents an RF short circuit between the first contacting element Kl and the second contacting element K2 (or the two electrodes).

[0100] Bruker Switzerland AG 10.12.2025 SP14057PCT El, E2 of the battery 1) via the DC current element 4 is prevented, and the resonance characteristics of the RF resonant circuit 3 are independent and unaffected by the characteristics of the DC current element 4.

[0101] Fig. 3 shows a further embodiment of an NMR measuring head 2 according to the invention. Only the essential differences to the design of Fig. 2 are explained.

[0102] The NMR probe 2 is shown connected to an NMR console 6, which can transmit RF pulses to the RF resonant circuit 3 (or to battery 1) and also receive RF signals from the RF resonant circuit 3 (or from battery 1). The NMR console 6 is connected to the first RF terminal H1 and to the second RF terminal H2. The second RF terminal H2 is grounded and thus connected to the second contact element K2.

[0103] The first RF connection Hl is electrically connected to the first contact element Kl via a matching capacitor 31 (with capacitance value CM). The matching capacitor 31 fulfills two functions. Firstly, it serves to match the impedance of the RF resonant circuit 3 (or the entire assembly consisting of the RF resonant circuit 3 and the matching capacitor 31), typically to 50 ohms (corresponding to the impedance in the NMR console 6), at least at the measurement frequency REF. Correct matching maximizes the electromagnetic energy radiated into the battery 1 and minimizes reflections. The matching capacitor 31 thus represents an impedance matching element 7. Furthermore, with correct design of the preamplifier, the signal-to-noise ratio is maximized in the receive mode.

[0104] On the other hand, the matching capacitance 31 also blocks DC current from the first contacting element Kl (and thus from the battery 1 and the DC current element 4) to the first RF connection Hl. The matching capacitance 31 therefore also represents a DC blocking capacitance 8 for direct current. Accordingly, the NMR-

[0105] Bruker Switzerland AG 10.12.2025 SP14057PCT Console 6 is not affected by direct current, and the one connected to the battery

[0106] 1. The flowing direct current is determined solely via the DC current element 4.

[0107] Fig. 4 shows a further embodiment of an NMR measuring head 2 according to the invention. Only the essential differences to the design of Fig. 3 are explained.

[0108] In the illustrated embodiment, in addition to the matching capacitor 31, a matching inductance 32 (with inductance value LM) is also provided. The matching inductance 32 is connected here between the first RF terminal Hl and the matching capacitor 31. The other end of the matching inductance 32 is connected to ground.

[0109] The Machting capacitor 31 and the matching inductor 32 are each impedance matching elements 7. Together they form an impedance matching network, which sets the impedance of the RF resonant circuit 3 (or the combined impedance of the RF resonant circuit 3 and the impedance matching network). The advantage of this circuit is that the impedance matching can be performed independently of the frequency matching of the RF resonant circuit 3.

[0110] Figure 5 shows a further embodiment of an NMR measuring head 2 according to the invention, to illustrate the general possibilities for setting up an impedance matching network. Only the essential differences to Figure 3 are explained.

[0111] The RF resonant circuit 3 is formed here by the battery 1, whose electrodes El, E2 are conductively connected for RF current via a first partial tuning impedance 33 (with impedance value ZTI) and a second partial tuning impedance 34 (with impedance value ZT2). The first partial tuning impedance 33 and the second partial tuning impedance 34 are connected in series. One of the partial tuning impedances 33, 34, or both partial tuning impedances 33, 34 together, constitute the tuning capacitance of the RF resonant circuit 3. At least one of the partial-

[0112] Bruker Switzerland AG 10.12.2025 SP14057PCT Tuning impedances 33, 34 contains a series capacitor (not shown in detail) so that a parallel path to battery 1 for direct current between the contact elements Kl, K2 is blocked.

[0113] The first RF terminal Hl is conductively connected to the first contact element Kl via the first matching impedance 35 (with impedance value ZMI) for RF current. Typically, the first matching impedance 35 contains a series capacitor that acts as a DC blocking capacitance.

[0114] A second matching impedance 36 (with impedance value ZM2) is connected between the first RF terminal Hl and the first matching impedance 35. The other end of the second matching impedance 36 is connected to ground.

[0115] A balancing impedance 37 (with impedance value Zs) is connected to a center tap 8 between the partial tuning impedances 33 and 34. The other end of the balancing impedance 37 is connected to ground.

[0116] The first contact element K2 is connected to the first DC terminal D1 via the first block element Bl (see above). The second contact element K2 is connected to the second DC terminal D2 via a second block element B2. The second block element B2 is conductive for direct current but blocks RF current at least in the region of the resonant frequency REF of the RF resonant circuit 3. In general, the second block element B2 attenuates RF current at frequency REF by at least a factor of 10, preferably at least a factor of 100, and particularly preferably at least a factor of 1000.

[0117] Note that in the case of ZT2 = 0 and Zs = 0, the second contacting element K2 is connected to ground, and then the second blocking element B2 is not needed (not shown in detail, but see e.g. Fig. 3).

[0118] The general design of the NMR measuring head 2 of Fig. 5 can be assigned to the designs already presented as follows:

[0119] Bruker Switzerland AG 10.12.2025 SP14057PCT In the design of Fig. 2, ZTI =CT was chosen, and all other impedances were chosen to be zero.

[0120] In the design shown in Fig. 3, ZTI =CT and ZMI =CM were chosen, and all other impedances were set to zero.

[0121] In the design shown in Fig. 4, ZTI =CT, ZMI =CM, and ZM2 =LM were chosen, and all other impedances were set to zero.

[0122] It should be noted that the impedance matching networks shown in Fig. 5 and the other figures are merely examples, and other alternatives from the prior art can also be used within the scope of the invention.

[0123] Fig. 6 shows a further embodiment of an NMR measuring head 2 according to the invention. Only the essential features and differences to the design of Fig. 5 are explained.

[0124] In this embodiment, the tuning capacitance 30 (with capacitance value CT) is formed in one piece, which connects the contact elements Kl, K2 together and thereby sets up the RF resonant circuit 3 with the battery 1.

[0125] A matching capacitance 31 (with inductance value CM) is also provided, which connects the first RF terminal Hl to the first contacting element Kl in a conductive manner for RF current.

[0126] Furthermore, a balancing capacitor 38 (with capacitance value Cs) is provided, which connects the second contact element K2 to ground. Note that the second RF connection H2 is also connected to ground here, so the balancing capacitor 38 connects the second contact element K2 to the second RF connection H2. The balancing capacitor 38 also contributes to the matching process.

[0127] Bruker Switzerland AG 10.12.2025 SP14057PCT The matching capacitance 31 and the symmetrization capacitance 38 are chosen here with (approximately) the same capacitance values ​​CM, CS, thereby obtaining electrical symmetry at the contacting elements Kl and K2 by creating a virtual ground in the middle of the tuning capacitance 30 through the impedance matching elements 7.

[0128] In the nomenclature of Fig. 5, in the embodiment of Fig. 6, ZTI =CT, ZMI =CM, and Zs =Cs are chosen, and all other impedances are chosen to be zero.

[0129] Fig. 7 shows a first sub-variant of the embodiment of the NMR measuring head of Fig. 6; only the essential deviations and special features are explained.

[0130] In this first sub-variant, the block elements Bl and B2 are each configured as low-pass filters 9. Here, the low-pass filters 9 are each implemented simply by a low-pass filter inductor 39 (with inductance value LTPF). Note that LTPF > L Bat , in order to achieve good filtering effect for RF current without significantly affecting the resonator current.

[0131] Fig. 8 shows a second sub-variant of the embodiment of the NMR measuring head of Fig. 6; only the essential deviations and special features are explained.

[0132] In this second sub-variant, the block elements Bl, B2 are each configured as a low-pass filter 9, which in turn are each connected by a low-pass filter inductance 39 (with inductance values ​​LTPF). B1 , LTPF B2 are trained. Note that LTPF applies. B1 > L Bat and L T pF B2 >L Ba tt.

[0133] Furthermore, a leakage capacitance 40 (with capacitance value CAN) is located between the first block element Bl or the associated low-pass filter inductance 39 and the first DC connection Dl. B1 ) connected. The leakage capacitance 40 is, on the other hand, connected to ground.

[0134] Bruker Switzerland AG 10.12.2025 SP14057PCT Furthermore, a leakage capacitance 40 (with capacitance value CAN) is located between the second block element B2 or the associated low-pass filter inductance 39 and the second DC connection D2. B2 ) connected. The leakage capacitance 40 is, on the other hand, connected to ground.

[0135] A series resonant frequency SRI can be assigned to the series connection of the low-pass filter inductance 39 of the first block element Bl and the associated leakage capacitance 40 im:

[0136] Furthermore, a series resonant frequency SR2 can be assigned to the series connection of the low-pass filter inductance 39 of the second block element B2 and the associated leakage capacitance 40:

[0137] The sub-variant shown in Fig. 8 can be used in two different applications.

[0138] In the first application (“non-resonant variant”), SRI and SR2 are each chosen to be significantly smaller than REF. For this purpose, low-pass filter inductors 39 with comparatively high inductance values ​​LTPF are typically used. B1 , LTPF B2 chosen. By means of a high impedance through a high C *LTPF B1 or C *LTPF B2(where o indicates the angular frequency of the NMR measurement), achieved through a large inductance value, a high reflection of the RF waves at the low-pass filter inductor 39 is obtained. The leakage capacitance 40 then dissipates the portions of the RF wave that still penetrate the low-pass filter inductor 39 to ground, thus improving the blocking effect. The first application is

[0139] Bruker Switzerland AG 10.12.2025 SP14057PCT broadband blocking. In the case described here where SRI and SR2 << REF, SRI and SR2 can be either identical or different.

[0140] In the second application case (“resonant variant”), SRI and SR2 each correspond at least approximately to the resonant frequency REF of the RF resonant circuit 3. This second variant is based on a “ground-to-resonant circuit,” meaning that a virtual ground connection is generated for a specific frequency (i.e., the series resonant frequency SRI, SR2). Via the respective leakage capacitance 40, together with the associated low-pass filter inductance 39, RF current in the region of the frequency REF, originating from the contact elements Kl, K2, can be leaked to ground with very low resistance and thus kept away from the DC terminals D1, D2. This second application case can be described as narrowband blocking. In the case described here, where SRI and SR2 approximately correspond to REF, they are preferably chosen to be different from each other in order to avoid resonance splitting.Typically, SRI and SR2 each deviate from REF by a maximum of 10% (relative to REF).

[0141] Fig. 9 shows a third sub-variant of the embodiment of the NMR measuring head of Fig. 6; only the essential deviations and special features are explained.

[0142] In this third sub-variant, the block elements Bl, B2 are each configured as a resonant circuit 11. Each resonant circuit 11 is formed by a resonant circuit inductance 41 (with inductance value Ls). P ) and a resonant circuit capacity of 42 (with capacity value Cs) P ), which are connected in parallel to each other (parallel resonant circuit). L applies. Sp > Lßatt.

[0143] Each retard circuit 11 has a retard frequency SPF with

[0144] Bruker Switzerland AG 10.12.2025 SP14057PCT where SPF is set (at least approximately) equal to the resonant frequency REF of the RF resonant circuit 3. Accordingly, the blocking circuit 11 blocks RF current of frequency REF. Consequently, no RF current of frequency REF passes through the blocking elements Bl, B2. RF pulses from the NMR console 6 and RF signals from the battery 1 do not reach the DC terminals D1, D2. Conversely, no high-frequency interference currents that might be present at the DC terminals D1, D2 can reach the contacting elements Kl, K2.

[0145] Fig. 10 shows a further embodiment of an NMR measuring head 2 according to the invention. Only the essential differences to the design of Fig. 5 are explained.

[0146] In this embodiment, the tuning capacitor 30 is formed in two parts, with the first partial tuning capacitor 43 (with capacitance value CTI) and a second partial tuning capacitor 44 (with capacitance value CT2). The first partial tuning capacitor 43 and the second partial tuning capacitor 44 are connected in series and connect the first contact element Kl to the second contact element K2 in a conductive manner for RF current, but blocking DC current; this establishes the RF resonant circuit 3, which contains the battery 1.

[0147] Impedance matching is achieved here via the matching capacitance 31 (with capacitance value CM), which is simultaneously blocking DC current as the DC blocking capacitance 8.

[0148] The center tap 8 between the partial tuning capacitors 43 and 44 provides a ground connection. Typically, the capacitance values ​​CTI and CT2 of the partial tuning capacitors 43 and 44 are approximately equal (typically with a difference of no more than 20%, relative to the larger value).

[0149] In the nomenclature of Fig. 5, in the embodiment of Fig. 10, ZTI = CTI and Z are represented here. T 2=CT2 and ZMI=CM were chosen, and all other impedances are chosen to be zero.

[0150] Bruker Switzerland AG 10.12.2025 SP14057PCT Fig. 11 shows, by way of example, a perspective view of a battery holder 10 which can be integrated into an NMR measuring head according to the invention.

[0151] The battery holder 10 contains a battery 1, which here is designed as a button cell 12. In the illustrated design, the battery holder 10 comprises a metallic base 13 and a metallic bracket 14, which together enclose a measuring position 15 on which the battery 1 is arranged.

[0152] In the present case, two springs 16 are formed in the metallic bracket 14, which are pre-tensioned towards the base 13. The two metallic springs 16 press against the top of the battery 1. The battery 1 is thus elastically clamped in the battery holder 10 by the springs 16; this fixes the battery 1 to the measuring station 15.

[0153] The upper side of battery 1, which forms its first electrode El, contacts the springs 16 and thus the bracket 14. The lower side of battery 1, which forms its second electrode E2, rests against the base 13. Therefore, in the illustrated configuration, the bracket 14 can be considered the first contact element Kl, and the base 13 the second contact element K2. The base 13 and the bracket 14 are galvanically isolated from each other.

[0154] In the illustrated configuration, however, the base 13 and the bracket 14 are connected to each other via both capacitor 45 and capacitor 46. Capacitors 45 and 46 thus form a parallel circuit, which together establishes the tuning capacitance 30; the capacitance values ​​of capacitors 45 and 46 add up to the total capacitance value CT of the tuning capacitance 30. The two capacitors 45 and 46 are arranged on opposite sides, here opposite lateral sides, of the battery holder 10.

[0155] Fig. 12 schematically shows an NMR spectrometer system 20 according to the invention in an exemplary embodiment.

[0156] Bruker Switzerland AG 10.12.2025 SP14057PCT The NMR spectrometer system 20 comprises an NMR measuring head 2, at the (here upper) end of which the measuring station 15 (shown with a dashed line) for the battery 1 is located. The NMR measuring head 2 is inserted from below into the room temperature bore 22 of a cryostat 21. The measuring station 15 is accordingly located within the room temperature bore 22 of the cryostat 21. A superconducting magnetic coil 23 is arranged in the cryostat 21, which generates a static magnetic field in the area of ​​the measuring station 15. In addition, a shim system 24 is provided, which homogenizes the magnetic field in the area of ​​the measuring station 15. The shim system 24 is inserted from above into the room temperature bore 22. The superconducting magnet coil 23 and the shim system 24 together form the magnet 25 (also called background magnet) of the NMR spectrometer system 20.

[0157] The NMR probe 2 is connected to an NMR console 6 via its RF connections. RF pulses can be injected into the NMR probe 2 using the NMR console 6, and RF signals can be read out of the NMR probe 2.

[0158] Furthermore, a battery controller 26 is provided. The battery controller 26 controls a DC current element 4, which can provide charging and / or discharging currents for the battery 1. In the illustrated embodiment, the battery controller 26 and the DC current element 4 can be used to selectively set and change either a charging or a discharging current for the battery 1 at the measuring station 15. In the illustrated embodiment, the DC current element 4 is integrated into the battery controller 26, and the integrated DC current element 4 is connected to the NMR measuring head 2 via the DC connections. However, it is also possible, for example, to integrate the DC current element into the NMR measuring head (not shown in detail).

[0159] The NMR console 6 and the battery controller 26 are connected to a control PC 27, which allows for the overall monitoring and control of the NMR measurement on battery 1. It is also possible to integrate the battery controller into the control PC (not shown in detail).

[0160] Bruker Switzerland AG 10.12.2025 SP14057PCT The NMR spectrometer system 20 and a battery arranged at the measuring station 15 together form an NMR measuring arrangement 28 according to the invention, with which NMR measurements can be carried out on the battery 1 while the battery 1 is being discharged or charged at the same time.

[0161] Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT Reference symbol list

[0162] 1 battery

[0163] 2 NMR measuring head

[0164] 3 HF resonant circuit

[0165] 4 DC current element

[0166] 5 DC charger

[0167] 6 NMR console

[0168] 7 Impedance matching element

[0169] 8 DC blocking capacity

[0170] 9 low-pass filters

[0171] 10 Battery holder

[0172] 11 restricted area

[0173] 12 button cell

[0174] 13 metallic floor

[0175] 14 metallic brackets

[0176] 15 measuring station

[0177] 16 metallic springs

[0178] 20 NMR spectrometer system

[0179] 21 Cryostat

[0180] 22 Room temperature bore

[0181] 23 superconducting magnetic coil

[0182] 24 shim system

[0183] 25 Magnet

[0184] 26 Battery control

[0185] 27 control PCs

[0186] 28 NMR measurement setup

[0187] 30 Tuning capacity

[0188] 31 Matching capacity

[0189] 32 Matching inductance

[0190] 33 First partial tuning impedance

[0191] 34 second partial tuning impedance

[0192] 35 first matching impedance

[0193] Bruker Switzerland AG 10.12.2025 SP14057PCT 36 second matching impedance

[0194] 37 Balancing Impedance

[0195] 38 Symmetrization capacity

[0196] 39 Low-pass filter inductance

[0197] 40 Discharge capacity

[0198] 41 Blocking circuit inductance

[0199] 42 Blocking circuit capacity

[0200] 43 first partial tuning capacity

[0201] 44 second part tuning capacity

[0202] 45 Capacitor

[0203] 46 Capacitor

[0204] Bl first block element

[0205] B2 second block element

[0206] Csatt Battery capacity value

[0207] CM Capacity Value of Matching Capacity

[0208] C's capacity value of the symmetrization capacity

[0209] Cs P Capacity value of the blocking circuit capacity

[0210] CT capacity value of the tuning capacity

[0211] CTI capacity value of the first partial tuning capacity

[0212] CT2 capacity value of the second part of the tuning capacity

[0213] First DC connection

[0214] D2 second DC connector

[0215] The first electrode

[0216] E2 second electrode

[0217] First RF connection

[0218] H2 second RF connection

[0219] Kl first contact element

[0220] K2 second contact element

[0221] Lßatt inductance value of the battery

[0222] LM inductance value of the matching inductance

[0223] Ls P Inductance value of the resonant circuit inductance

[0224] Rmetai value of the ohmic resistance of the metallic parts of the battery

[0225] REF Resonance frequency of the HF resonant circuit

[0226] Bruker Switzerland AG 10.12.2025 SP14057PCT Reiectroiyte Value of the ohmic resistance across the electrolyte in the battery

[0227] SPF blocking frequency

[0228] SRI series resonance frequency (block element 1)

[0229] SR2 Series Resonance Frequency (Block Element 2) ZMI Impedance Value of the First Matching Impedance

[0230] ZM2 impedance value of the second matching impedance

[0231] Zs impedance value of the balancing impedance

[0232] ZTI impedance value of the first partial tuning impedance

[0233] ZT2 Impedance value of the second partial tuning impedance

[0234] Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT

Claims

Patent claims 1. NMR measuring head (2) for performing NMR measurements on a battery (1), comprising i) a measuring station (15) for a battery (1), with a first contact element (Kl) for a first electrode (El) of the battery (1) and a second contact element (K2) for a second electrode (E2) of the battery (1), ii) a tuning capacitor (30), and iii) a first RF connection (Hl) and a second RF connection (H2) for an NMR console (6), wherein the first contact element (Kl) and the second contact element (K2) are conductively connected for RF current via the tuning capacitor (30), so that an RF resonant circuit (3) can be set up with a battery (1) to be arranged at the measuring station (15), and wherein the first RF connection (Hl) is conductively connected to the first contact element (Kl) for RF current. is and the second RF connection (H2) is conductively connected to the second contact element (K2) for RF current,iv) a first DC terminal (D1) and a second DC terminal (D2) for a DC current element (4), and v) at least a first blocking element (Bl) which is conductive for DC current and blocking for RF current at least in the region of a provided resonant frequency REF of the RF resonant circuit (3), wherein the first DC terminal (D1) is conductively connected to the first contacting element (Kl) via the first blocking element (Bl), and the second DC terminal (D2) is conductively connected to the second contacting element (K2) for DC current. Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT 2. NMR measuring head (2) according to claim 1, characterized in that the measuring station (15) is set up for a battery (1) which is designed as a button cell (12).

3. NMR measuring head (2) according to claim 1 or 2, characterized in that the second RF connection (H2) is connected to ground.

4. NMR measuring head (2) according to one of claims 1 to 3, characterized in that the tuning capacitance (30) is formed with a first partial tuning capacitance (43) and a second partial tuning capacitance (44), wherein the first partial tuning capacitance (43) and the second partial tuning capacitance (44) are connected in series in the RF resonant circuit (3), and that a center tap (8) between the first partial tuning capacitance (43) and the second partial tuning capacitance (44) is connected to ground.

5. NMR measuring head (2) according to one of claims 1 to 3, characterized in that the second contacting element (K2) is connected to ground.

6. NMR measuring head (2) according to one of claims 1 to 4, characterized in that the NMR measuring head (2) further comprises - a second block element (B2) which is permeable to DC current and blocking to RF current at least in the range of the intended resonant frequency REF of the RF resonant circuit (3), wherein the second DC connection (D2) is conductively connected to the second contacting element (K2) via the second block element (B2).

7. NMR measuring head (2) according to one of the preceding claims, characterized in that the NMR measuring head (2) comprises one or more impedance matching elements (7). Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT 8. NMR measuring head (2) according to claim 7, characterized in that one of the RF connections (H1, H2), in particular the first RF connection (H1), is connected to its associated contacting element (K1, K2) via a matching capacitance (31).

9. NMR measuring head (2) according to claim 7 or 8, characterized in that the tuning capacitance (30) and the impedance matching element(s) (7) are connected such that at least approximately symmetrical potentials are obtained at the two contacting elements (Kl, K2) during measurement operation, in particular wherein the first RF connection (Hl) is connected to the first contacting element (Kl) via a matching capacitance (31) in a conductive manner for RF current and the second contacting element (K2) is connected to ground via a balancing capacitance (38) in a conductive manner for RF current and the matching capacitance (31) and the balancing capacitance (38) have at least approximately the same capacitance value (CM, CS).

10. NMR measuring head (2) according to one of the preceding claims, characterized in that at least one of the RF connections (H1, H2) is connected to its associated contacting element (K1, K2) via a DC blocking capacitance (8).

11. NMR measuring head (2) according to one of claims 1 to 10, characterized in that a respective block element (Bl, B2) is designed as a low-pass filter (9).

12. NMR measuring head (2) according to claim 11, characterized in that the low-pass filter (9) is designed with a low-pass filter inductance (39). Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT 13. NMR measuring head (2) according to claim 12, characterized in that an inductance value LTPF of the low-pass filter inductance (39) is greater than an inductance value L Ba tt of the battery (1) in the RF resonant circuit (3), in particular where LTPF > 1 nH or 1 nH < LTPF < 50 uH or 100 nH < LTPF — 25 uH.

14. NMR measuring head (2) according to one of claims 12 or 13, characterized in that a leakage capacitance (40) is connected between each block element (Bl, B2) and its associated DC connection (Dl, D2), which leads to ground, and that each series resonant frequency (SRI, SR2), which belongs to a series connection of the low-pass filter inductance (39) of the respective block element (Bl, B2) with the associated leakage capacitance (40), is significantly smaller than the intended resonant frequency REF of the RF resonant circuit (3), in particular by at least a factor of 5 smaller, preferably by at least a factor of 10 smaller, most preferably by at least a factor of 50 smaller.

15. NMR measuring head (2) according to one of claims 12 or 13, characterized in that a leakage capacitance (40) is connected between each block element (Bl, B2) and its associated DC connection (Dl, D2), which leads to ground, and that each series resonant frequency (SRI, SR2), which belongs to a series connection of the low-pass filter inductance (39) of the respective block element (Bl, B2) with the associated leakage capacitance (40), corresponds at least approximately to the intended resonant frequency REF of the RF resonant circuit (3). Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT 16. NMR measuring head (2) according to one of claims 1 to 10, characterized in that a respective blocking element (Bl, B2) is designed as a blocking circuit (11), wherein the blocking circuit (11) blocks in the region of the intended resonance frequency REF of the RF resonant circuit (3).

17. NMR measuring head (2) according to one of the preceding claims, characterized in that a battery holder (10) is provided with which the battery (1) can be fixed to the measuring station (15), so that when the battery (1) is arranged in the battery holder (10), the first contacting element (Kl) contacts the first electrode (El) of the battery (1) and the second contacting element (K2) contacts the second electrode (E2) of the battery (1), in particular wherein the battery (1) can be elastically clamped in the battery holder (10) with the first contacting element (Kl) and / or the second contacting element (K2), that the first contacting element (Kl) and the second contacting element (K2) are galvanically isolated from each other, and that the first contacting element (Kl) and the second contacting element (K2) are connected to each other by at least one capacitor (45, 46).

18. NMR measuring head (2) according to claim 17, characterized in that the first contacting element (Kl) and the second contacting element (K2) are connected to each other by two capacitors (45, 46), in particular on opposite sides of the battery holder (10).

19. NMR spectrometer system (20), comprising - an NMR measuring head (2) according to one of the preceding claims, - an NMR console (6) which is connected to the RF connections (H1, H2), - a DC current element (4) which is connected to the DC terminals (D1, D2), Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT - one or more control devices (26, 27) for the NMR console (6) and the DC current element (4), in particular comprising a control PC (27), - and a magnet (25) for generating a static magnetic field at the measuring station (15) for the battery (1), in particular wherein the magnet (25) comprises a shim system (24).

20. NMR spectrometer system (20) according to claim 19, characterized in that the DC current element (4) is a DC charger (5) or a DC discharger.

21. NMR measuring arrangement (28) comprising an NMR spectrometer system (20) according to claim 19 or 20 and a battery (1) arranged at the measuring station (15) for the battery (1), wherein a first electrode (El) of the battery (1) is contacted with the first contacting element (Kl), and a second electrode (E2) of the battery (1) is contacted with the second contacting element (K2).

22. Use of an NMR measurement arrangement (28) according to claim 21, wherein simultaneously - the battery (1) is charged or discharged using the DC current element (4), - and an NMR measurement is performed on the battery (1) using the NMR console (6) and the NMR measuring head (2). Bruker Switzerland AG 12 / 10 / 2025 SP14057PCT

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