Acoustic analysis systems and methods for electrochemical devices and materials

Abstract

An electrochemical device or electrochemical material acoustic analysis system, comprising: a housing 102 configured to receive an electrochemical device or material S01 for acoustic analysis; at leas

Description

Field of the invention The present disclosure relates to systems and methods for acoustic analysis of electrochemical devices and materials, in particular using an electromagnetic acoustic transducer and / or motion controller. Background Acoustic analysis can be used to determine the condition and / or properties of electrochemical devices, such as electrochemical cells and / or batteries, based on a measurement of the elastic properties and internal interfaces of the electrochemical device using acoustic waves, typically in the ultrasonic regime. The acoustic signal that is received after propagating through the electrochemical device or material can reveal information about the material properties and internal structure. Conventional acoustic analysis methods require contact between an acoustic transducer and the electrochemical device or material being analysed. Due to the required contact, existing methods also require the use of a liquid, gel, or solid couplant between the acoustic transducer and the electrochemical device or material to reduce acoustic attenuation between the transducer and the sample. This can cause problems for many electrochemical devices and materials which are sensitive to external couplants, such as water-based couplants. The quantity, composition, and material properties of the couplant used can also influence the acoustic waveform of the measurement, meaning varied and inconsistent application of couplant to the electrochemical device can impact the reliability of acoustic measurements. In addition, the application of couplant poses a significant barrier to automation and scaling of acoustic analysis for electrochemical devices and materials. Furthermore, the force applied to the transducer to contact the sample surface can also affect the properties of the acoustic wave and quality of the measurement, particularly the amplitude of the acoustic signal. Summary of the invention Aspects of the invention are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects. An aspect of the invention provides an acoustic analysis system for an electrochemical device or electrochemical material, the system comprising a housing configured to receive an electrochemical device or electrochemical material for acoustic analysis, and at least one electromagnetic acoustic transducer (EMAT) configured for contactless acoustic analysis of the electrochemical device or electrochemical material received by the housing. For example, the acoustic analysis system may be an electrochemical device acoustic analysis system and / or electrochemical material acoustic analysis system. In some examples, the electrochemical device may be an electrochemical cell or battery. The technique of probing using acoustics in this manner can be applied to a range of battery sizes and cell form factors, including but not limited to pouch cells, prismatic cells, and cylindrical cells. However, the skilled person will understand that other electrochemical devices may be used; for example, but not limited to, fuel cells, galvanic cells, electrolysers, and capacitors. Electrochemical devices may also include electrochemical components, such as, but not limited to, electrodes. Electrochemical materials may include materials that are suitable for use in electrochemical devices, for example that either generate electrical energy from a chemical reaction (e.g., a battery during discharge) or facilitate a chemical reaction through the application of electricity (e.g., electrolysis of water to produce hydrogen). Whilst electrochemical materials are typically incorporated into electrochemical devices, analysis of the materials themselves can be helpful to predict the performance of the resulting electrochemical device. In particular, analysis of electrochemical materials may have applications in quality control, for example during manufacture or assembly of electrochemical devices. In some examples, the electrochemical material may be, but is not limited to, an electrode material, or other material or component for use in an electrochemical device. For example, acoustic analysis may be used to determine the condition or properties of an electrochemical cell electrode based on a measurement of at least one of the elastic properties, density, thickness, internal interfaces, and / or internal interphases of the electrode. In particular, acoustic analysis may reveal information including but not limited to electrolyte wetting, electrolyte degradation, gas formation, solid-electrolyte interphase properties, delamination, penetration, internal short circuit, temperature, thermal runaway, changes in material porosity, thickness, current collector corrosion, lithium plating, metal dissolution, etc. The variation in the elastic properties can also be correlated to changes in the state-of-charge or state-of-health or state-of-safety of the electrochemical devices. It may also be used to study battery components and their behaviours including but not limited to electrodes, electrode drying, slurry composition, electrolyte properties, etc. These properties may be particularly relevant to analysis of batteries and electrochemical cells. However, the skilled person will understand that acoustic analysis may also reveal information relating to fuel cells, including but not limited to electrode delimitation, flooding or excess water content in the cell, cracking of the gas diffusion or microporous layer, bipolar plate corrosion or fracture, mismatched electrodes or poor contact between electrodes, etc. In addition, acoustic analysis may also reveal information relating to electrolysers, including but not limited to membrane dehydration, fouling, excessive gas in cell, catalyst layer cracking, pinhole formation, catalyst poisoning, etc. The skilled person will also understand that acoustic analysis may reveal information about other electrochemical devices; for example, but not limited to, galvanic cells and capacitors. Numerous surprising advantages of using an electromagnetic acoustic transducer (EMAT) configured for contactless acoustic analysis of the electrochemical device or electrochemical material have been identified by the applicant. For example, the electromagnetic acoustic transducer (EMAT) configured for contactless acoustic analysis of the electrochemical device or electrochemical material may be advantageous for acoustic analysis system for an electrochemical device or electrochemical material because contactless analysis eliminates measurement errors and inaccuracies which result from inconsistent contact with the surface of the electrochemical device or electrochemical material being analysed. Furthermore, the use of a non-contact transducer may enable the deployment of acoustic analysis at the earliest possible stage of a battery production line (e.g., during or after coating of electrodes during electrode manufacturing) and will enable measurement capabilities to be deployed at a location where acoustic analysis can significantly minimise wastage when defects are identified allowing rapid feedback to inform control and quality control strategies. This may ultimately reduce material wastage in production lines. Contactless acoustic analysis may also be advantageous to avoid sample damage and / or contamination. There is also no need to establish a certain compression with the sample which can be time consuming. Contactless acoustic analysis may also have improved safety aspects relative to contact analysis, such as chemical and electrical short circuiting, and an improved throughput due to more rapid scanning of samples. The contactless acoustic analysis using the EMAT may also be used to monitor an electrochemical cell or battery as it is operating in use. The acoustic measurements derived from the contactless acoustic analysis of the cell in use may optionally be used to control operation of a battery management system (BMS). For example, the electromagnetic acoustic transducer may be configured for acoustic analysis of the electrochemical device or electrochemical material without the use of a couplant between the electromagnetic acoustic transducer and the electrochemical device or electrochemical material. Couplants are materials which are conventionally used to facilitate transmission of acoustic energy, such as ultrasonic energy, from the transducer into the specimen, due to large acoustic impedance mismatch between air and the test specimen. The use of an electromagnetic acoustic transducer may be advantageous to improve measurement reliability by overcoming the need for couplant which can introduce variation and inconsistencies into acoustic measurements. This also extends the range of electrochemical devices and materials which can be studied by acoustic analysis, including those materials and devices which are sensitive to external couplants which are often liquid and / or water based. In some examples, the electromagnetic acoustic transducer may comprise a magnet, such as a permanent magnet, and a coil configured for application of an AC current. The coil may be configured to provide a first magnetic field, and the magnet may be configured to provide a second magnetic field. The first magnetic field and the second magnetic field are configured to interact to generate Lorentz force, wherein the Lorentz force is configured to induce an acoustic wave in the electrochemical device or electrochemical material. The electromagnetic acoustic transducer may then be configured to measure the acoustic wave in transmission and / or reflectance mode to determine at least one characteristic of the electrochemical device or electrochemical material. In some examples, the electromagnetic acoustic transducer may be a compression wave electromagnetic acoustic transducer configured to induce compressional acoustic waves in the electrochemical device or electrochemical material. This may be advantageous as the applicant has surprisingly found that compression wave electromagnetic acoustic transducers obtain better acoustic measurements for some electrochemical devices, in particular electrochemical cells and batteries, such as pouch cells, compared to shear wave electromagnetic acoustic transducers. This is surprising in light of the common assumption that compression wave EMAT probes are typically less efficient and sensitive than their shear wave counterparts. The enhanced performance of compression wave electromagnetic acoustic transducers is believed to arise from a better interaction of the ultrasound waves with the layered structure of the electrochemical cells or batteries, in particular because acoustic waves from a compression wave electromagnetic acoustic transducer propagate perpendicular to this layered structure.. However, the skilled person will understand that, in other examples, the electromagnetic acoustic transducer may be any other electromagnetic acoustic transducer, such as a shear wave electromagnetic acoustic transducer configured to induce shear acoustic waves in the electrochemical device or electrochemical material, including but not limited to a radially polarised shear wave EMAT or an angled shear wave EMAT. In some examples, the system may further comprise an EMAT adapter, such as but not limited to an EMAT Adaptor GS2020. The EMAT adapter may be configured to improve the signal to noise performance of the EMAT. The EMAT adapter may also be configured to bridge between the EMAT probe and a flaw detector designed for piezoelectric transducers. This may be advantageous to allow EMATs and piezoelectric acoustic transducers to be used within the system interchangeably. The skilled person will understand that the housing may comprise a frame, or other support structure configures to receive the electrochemical device or electrochemical material. The housing need not be an enclosed housing. However, in other examples, the housing may be configured to substantially enclose the electrochemical device or electrochemical material, and the electromagnetic acoustic transducer (EMAT). This may be advantageous to control the testing environment within the enclosed housing. The system may further comprise a motion controller configured to enable translation and / or rotation of the at least one electromagnetic acoustic transducer relative to the electrochemical device or electrochemical material. The motion controller may advantageously allow for controlled, spatially resolved measurements to be conducted by, for example, rastering or scanning the transducer relative to the device or material being studied. For example, the motion controller may be configured to enable translation and / or rotation of the at least one electromagnetic acoustic transducer, or alternatively the motion controller may be configured to enable translation and / or rotation of the sample being analysed (e.g., the electrochemical device or electrochemical material). In some examples, the motion controller may be configured to enable translation and / or rotation of the at least one electromagnetic acoustic transducer and the sample being analysed. The motion controller may be configured to enable movement of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to a plurality of degrees of freedom. This may be advantageous to obtain measurements from the sensor head at a plurality of different positions and / or orientations relative to the electrochemical device or electrochemical material. The motion controller may be a multi-axis motion controller. For example, the motion controller may be configured to enable translation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least three degrees of freedom. For example, translation relative to x-, y-, and z- axes. Enabling translation according to three degrees of freedom, i.e., translation beyond solely in the xy plane, may be advantageous control the z axis position to allow for repeatable positioning and distance control between the EMAT and the sample under study which may vary in height and / or thickness. Translation relative to the z-axes, for example varying the distance between the acoustic transducer and the sample being studied, may also give important information about the sample and its material properties. In addition, or alternatively, the motion controller is configured to enable rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least one degree of freedom. For example, rotation relative to at least one of pitch, yaw, and roll axes. The electromagnetic acoustic transducer may be coupled to a sensor head, wherein the sensor head is coupled to the motion controller such that the motion controller is configured to enable translation and / or rotation of the sensor head. Optionally, the sensor head may additionally comprise at least one sensor configured to measure a non-acoustic property or characteristic of the electrochemical device or material. In some examples, the electromagnetic acoustic transducer may be coupled to a sensor head, wherein the sensor head is coupled to the motion controller via a detachable mounting. The detachable mounting may advantageously be configured to couple to a plurality of interchangeable sensor heads, wherein the plurality of interchangeable sensor heads may each comprise at least one different sensor and / or a different acoustic transducer. As such, multiple different transducers, including conventional piezoelectric acoustic transducers, laser induced ultrasonic transducers (LIUT), and / or electromagnetic acoustic transducers, can be mounted to the same system allowing for analysis and probing of electrochemical devices and / or materials with a range of different transducer types and setting. The detachable mounting also allows for rapid manual or automated changing of sensor heads. The motion controller may be configured to detect which sensor head is coupled to the detachable mounting and control the translation and / or rotation of the sensor head relative to the electrochemical device or electrochemical material based on the detected sensor head; for example, to accommodate for the range of different transducer types and settings. The system may further comprise a resilient biasing means coupled between the motion controller and the acoustic transducer, wherein the resilient biasing means is configured to bias the acoustic transducer into a first configuration. This may be advantageous to ensure that the acoustic transducer returns to the same position in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material. The resilient biasing means may additionally be configured to allow movement of the acoustic transducer. This may be advantageous to prevent damage to the acoustic transducer and electrochemical device or material in the event of contact between the acoustic transducer and the electrochemical device or material and / or allow movement of the acoustic transducer to conform to a surface of the electrochemical device or electrochemical material. In some examples, the resilient biassing means may be coupled between the motion controller and the sensor head. The system may further comprise a force sensor configured to sense an indication offeree applied to the at least one acoustic transducer. The motion controller may be configured to control the position and / or movement of the acoustic transducer relative to the electrochemical device or electrochemical material based on the indication offeree sensed by the force sensor. This may be advantageous in order to maintain a constant force between the acoustic transducer and the electrochemical device or electrochemical material for contact sensing applications, and / or to prevent damage to the acoustic transducer and electrochemical device or material in the event of contact or collision between the acoustic transducer and the electrochemical device or electrochemical material. Preventing damage to the electrochemical device or material, such as cells or batteries, during acoustic analysis may be particularly important as too much force or impact can trigger thermal runaway and cause the electrochemical device or material to catch fire or explode. In some examples, the system may comprise an array of acoustic transducers, wherein the acoustic transducers within the array are distributed such that the array is configured to cover at least a portion of a surface of the electrochemical device or electrochemical material. For example, the sensor head may comprise an array of acoustic transducers. This may be advantageous to allow for spatially resolved acoustic measurements, whilst reducing the number of positions the motion controller would have to cover. A plurality of transducers within the array may also be configured to operate as a phased array where beam steering can be utilised. This may be advantageous to focus the acoustic energy and improve the resolution. In some examples, each acoustic transducer comprises a pulse-receiver, wherein the pulse-receiver is configured to induce the acoustic transducer to induce or generate an acoustic waveform and / or receive at least one of: (i) a transmitted wave, and (ii) a reflected wave. The acoustic analysis system may further comprise a distance profiling means configured to sense the relative distance of the acoustic transducer from the electrochemical device or electrochemical material. The motion controller may additionally be configured to control the position and / or movement of the acoustic transducer based on the indication of relative distance sensed by the distance profiling means in order to maintain a constant distance between the acoustic transducer and the electrochemical device or electrochemical material during acoustic analysis. This may be advantageous to increase reliability and repeatability of acoustic analysis measurements and / or to prevent collision between the acoustic transducer and the electrochemical device or electrochemical material. In some examples, the distance profiling means may comprise a laser, such as a laser-based distance profiling system. The acoustic analysis system may further comprise a miniature snap-action switch configured to interrupt movement of the motion controller in the event that force applied to the acoustic transducer exceeds a threshold. This may be advantageous to prevent and reduce damage to the sensor head, including the acoustic transducer, as well as reduce damage to the sample, for example in the event of collision between the acoustic transducer and the electrochemical device or electrochemical material. Preventing damage to the electrochemical device or material, such as cells or batteries, during acoustic analysis may be particularly important as too much force or impact can trigger thermal runaway and cause the electrochemical device or material to catch fire or explode. The acoustic analysis system may further comprise an optical sensor configured for visual inspection of the electrochemical device or electrochemical material. Visual artefacts identified by visual inspection, for example such as crinkling on a pouch cell casing, may be configured to be correlated with the acoustic transducer measurements at the location of the visual artefact. This may be advantageous to correlate any anomalous or irregular surface features with anomalous or irregular acoustic measurements. The acoustic analysis system may further comprise a sensor configured to obtain identification information relating to the electrochemical device or electrochemical material, wherein the identification information is correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. For example, the sensor may comprise an optical sensor configured to read a QR code, barcode, or other visual identifier associated with the electrochemical device or material. Alternatively, or in addition, the sensor may comprise a short-range wireless receiver configured to read a short-range wireless identifier associated with the electrochemical device or material, such as an RFID tag, or similar. The motion controller may additionally be configured to control the position and / or movement of the acoustic transducer based on the identification information relating to the electrochemical device or electrochemical material, for example wherein the identification information may comprise information about a testing regime. The acoustic analysis system may further comprise a hall sensor and / or an eddy current detection probe, wherein the hall sensor and / or eddy current detection probe are configured for current mapping of the electrochemical device or electrochemical material, wherein the current mapping measurements are configured to be spatially correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. The acoustic analysis system may further comprise at least one temperature sensor configured to sense an indication of temperature of the electrochemical device or electrochemical material. The system may also comprise a temperature-controlled chamber configured to receive the electrochemical device or electrochemical material for acoustic analysis within the housing, wherein the temperature of the temperature-controlled chamber is configured to be controlled based on the indication of temperature of the electrochemical device or electrochemical material sensed by the at least one temperature sensor. The acoustic analysis system may further comprise an electrochemical test system configured to test the electrochemical device or electrochemical material during acoustic analysis using the at least one acoustic transducer. This may be advantageous to obtain acoustic measurements during cycling of an electrochemical device. For example, in cases wherein the electrochemical device is an electrochemical cell or battery, the test system, such as a battery cycler, would enable acoustic measurements to be taken during charge, discharge and / or ageing of the cell or battery. Alternatively or in addition, the test system may also be configured for electrochemical impedance spectroscopy (EIS) to obtain spatially resolved measurements relating to the electrochemical performance of a cell or battery. The acoustic analysis system may further comprise a nuclear isotope thickness measurement system, such as an isotope gauge. This may be advantageous for thickness monitoring of the sample. The acoustic analysis system may further comprise a laser interferometer configured for surface profiling of the sample. The housing of the acoustic analysis system may further comprise a sample bed, wherein the sample bed is configured to receive the electrochemical device or electrochemical material for acoustic analysis. The sample bed may further comprise at least one sensor configured to sense at least one characteristic of the electrochemical device or electrochemical material within the sample bed. This may be advantageous to enable at least one static sensor relative to the electrochemical device or material. For example, the sample bed may comprise an array of piezoelectric elements configured to receive acoustic signals in transmission mode once the acoustic signals have propagated through the electrochemical device or electrochemical material. This may be advantageous to enable the electromagnetic acoustic transducer to be scanned across the sample surface whilst the array of piezoelectric elements are configured to receive spatially resolved acoustic signals in transmission mode, induced by the electromagnetic acoustic transducer. The array of piezoelectric elements may, additionally or instead, be configured to provide an array of temperature measurements across a surface of the electrochemical device or electrochemical material in the sample bed, however the skilled person will understand that the sample bed may comprise an array of any suitable temperature sensors. The acoustic analysis system may further comprise a controller configured to adjust and / or optimise the acoustic parameters used for acoustic analysis based on acoustic measurements received from the electromagnetic acoustic transducer. Optionally, the controller may be configured to optimise the acoustic parameters used for acoustic analysis additionally based on measurements received from the auxiliary sensors (i.e., non-acoustic transducer sensors) in the acoustic analysis system. The optimisation of the acoustic parameters can be time and labour intensive, requiring specialist knowledge of the equipment and the acoustic techniques used to analyse samples. Thus, providing a controller to control and / or optimise the acoustic parameters based on information from the acoustic transducer, and optionally from other sensors described, may be advantageous to overcome this problem. For example, the controller may be configured to adjust and / or optimise the acoustic parameters based on identification of key features of the acoustic waveform, wherein the controller may be configured to optimise the acoustic parameters based on adjusting at least one acoustic parameter and identifying changes in the key features of the acoustic waveform based on a feedback loop, until these features are optimised. As an example, the controller may be configured to adjust at least one acoustic parameter and monitor changes in the signal to noise ratio of the acoustic waveform. The acoustic parameters may then be optimised according to the values or ranges of acoustic parameters which minimise the signal to noise ratio. The controller may also be configured to self-calibrate by comparing the variation of an acoustic waveform with parameters on a calibration block of known properties. The nature of the electromagnetic pulse can also be controlled and varied, for example by varying amplitude and frequency, to access different information about the internal properties of the electrochemical sample under test. Standard tests may be done with a transducer in the 5 MHz range; however, this may be lowered to between approximately 0.5 MHz to 5 MHz for thicker cells / electrochemical devices. Another aspect of the invention relates to a method of acoustic analysis for an electrochemical device or electrochemical material, the method comprising performing acoustic analysis on an electrochemical device or electrochemical material using an electromagnetic acoustic transducer (EMAT), wherein the electromagnetic acoustic transducer is configured for contactless acoustic analysis by generating Lorentz force, wherein the Lorentz force is configured to induce acoustic waves in the electrochemical device or electrochemical material. For example, the method may comprise performing acoustic analysis on an electrochemical device or electrochemical material using the acoustic analysis system of the first aspect of the invention, comprising the electromagnetic acoustic transducer. This may be advantageous for acoustic analysis system for an electrochemical device or electrochemical material because electromagnetic acoustic transducers can facilitate contactless acoustic analysis which eliminates measurement errors and inaccuracies from inconsistent contact with the surface of the electrochemical device or electrochemical material being analysed. It may also eliminate the need for couplant between the electromagnetic acoustic transducer and the electrochemical device or electrochemical material which can also improve measurement reliability by eliminating variation and inconsistencies caused by couplant. This also extends the range of electrochemical devices and materials which can be studied by acoustic analysis, including those materials and devices which are sensitive to external couplants which are often liquid and / or water based. Furthermore, contactless acoustic analysis may also be advantageous to avoid sample damage and / or contamination. There is also no need to establish a certain compression with the sample which can be time consuming. Contactless acoustic analysis may also have improved safety aspects relative to contact analysis, such as chemical and electrical short circuiting, and an improved throughput due to more rapid scanning of samples. Performing acoustic analysis using an electromagnetic acoustic transducer may comprise providing a first magnetic field using an electrical coil of the electromagnetic acoustic transducer, and providing a second magnetic field using a magnet of the electromagnetic acoustic transducer. The first magnetic field and the second magnetic field may be configured to interact to generate Lorentz force, wherein the Lorentz force is configured to induce an acoustic wave in the electrochemical device or electrochemical material. The method may further comprise measuring the acoustic wave from the electrochemical device or electrochemical material using the electromagnetic acoustic transducer to determine at least one characteristic of the electrochemical device or electrochemical material. The electromagnetic acoustic transducer may be a compression wave electromagnetic acoustic transducer configured to induce compressional acoustic waves in the electrochemical device or electrochemical material. This may be advantageous as the applicant has surprisingly found that compression wave electromagnetic acoustic transducers obtain better acoustic measurements for some electrochemical devices, in particular pouch cells, compared to shear wave electromagnetic acoustic transducers. However, the skilled person will understand that, in other examples, the electromagnetic acoustic transducer may be any other electromagnetic acoustic transducer, such as a shear wave electromagnetic acoustic transducer configured to induce shear acoustic waves in the electrochemical device or electrochemical material, including but not limited to a radially polarised shear wave EMAT or an angled shear wave EMAT. Providing the first magnetic field may comprise applying an AC current to the electrical coil of the electromagnetic acoustic transducer. The first magnetic field is configured to induce eddy currents in the electrochemical device or electrochemical material, and the second magnetic field is configured to interact with the induced eddy currents to generate the Lorentz force. Measuring the acoustic wave may comprise measuring the induced current and / or potential difference in a receiving coil of the electromagnetic acoustic transducer, wherein the current of the receiving coil is configured to be induced by contactless interaction between the acoustic wave propagating through the electrochemical device or electrochemical material in the presence of the second magnetic field. The receiving coil may be the same as or separate to the electrical coil configured to a first magnetic field. Performing acoustic analysis using an electromagnetic acoustic transducer may further comprise scanning the electromagnetic acoustic transducer across a surface of the electrochemical device or electrochemical material and performing acoustic analysis at discrete points across the surface of the electrochemical device or electrochemical material during scanning. This may be advantageous to obtain spatially resolved measurements at different points across the device or material. Alternatively, performing acoustic analysis using an electromagnetic acoustic transducer may further comprise translating and / or rotating the electrochemical device or electrochemical material to obtain spatially resolved measurements at different points across the device or material from a static electromagnetic acoustic transducer. In some examples, performing acoustic analysis using an electromagnetic acoustic transducer may comprise translating and / or rotating both the electrochemical device or electrochemical material and the electromagnetic acoustic transducer to obtain spatially resolved measurements at different points across the device or material. Scanning the electromagnetic acoustic transducer may comprise translating and / or rotating the electromagnetic acoustic transducer relative to the surface of the electrochemical device or electrochemical material using a multi-axis motion controller. For example, wherein a motion controller may be configured to translate and / or rotate the electromagnetic acoustic transducer. Alternatively, or in addition, the motion controller may be configured to translate and / or rotate the electrochemical device or electrochemical material. The acoustic wave may be measured in reflection mode, also referred to as pulse-echo mode, relative to the electrochemical device or electrochemical material. For example, the electrical coil of the electromagnetic acoustic transducer for generating the first magnetic field may also be configured to be the receiving coil, configured for measuring acoustic signals in reflection mode. Alternatively, or in addition, the acoustic wave may be measured in transmission mode relative to the electrochemical device or electrochemical material. The method may further comprise performing signal processing on the received acoustic wave to determine at least one characteristic of the electrochemical device or electrochemical material or electrochemical material. Example signal processing methods may include, but are not limited to, at least one of: (i) peak identification; (ii) peak quantification; (iii) multi-peak identification and / or quantification; (iv) total energy measurements; (v) Fourier transform analysis, or equivalent analysis in the spectral domain; and / or (vi) comparative analysis against a baseline measurement. In some examples, the signal processing may be performed by a machine learning model. The method may further comprise testing the electrochemical device or electrochemical material using an electrochemical testing system whilst performing acoustic analysis. This may be advantageous to obtain acoustic measurements during electrochemical testing, for example during cycling of the electrochemical device. For example, in cases wherein the electrochemical device is an electrochemical cell or battery, the method may further comprise charging and / or discharging the cell or battery using a cell cycler system whilst performing acoustic analysis. This could enable acoustic measurements to be taken during charge, discharge and / or ageing of the cell or battery. Additionally or instead, electrochemical testing may also comprise applying a sinusoidal current or voltage pulse to the cell, and comparing the difference in the resulting voltage or current to the resulting changes in the acoustic results, for example by performing transfer function analysis between electrochemical and acoustic measurements. Synchronisation of the electrochemical and acoustic testing may be advantageous to allow for techniques such as transfer function analysis between electrochemical tests and acoustic tests, and optionally other test data from auxiliary sensors including hall, temperature, and / or thickness measurements, etc. In another aspect of the invention, there is provided an acoustic analysis system for an electrochemical device or electrochemical material, the system comprising a housing, configured to receive an electrochemical device or electrochemical material for acoustic analysis, at least one acoustic transducer configured for acoustic analysis of an electrochemical device or electrochemical material; and a motion controller configured to enable translation and / or rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material received by the housing. This may be advantageous to provide controlled, spatially resolved acoustic measurements by, for example, rastering or scanning the acoustic transducer relative to the device or material being studied. For example, the motion controller may be configured to enable translation and / or rotation of the at least one acoustic transducer, or alternatively the motion controller may be configured to enable translation and / or rotation of the sample being analysed (e.g., the electrochemical device or electrochemical material received by the housing). In some examples, the motion controller may be configured to enable translation and / or rotation of both the at least one acoustic transducer and the sample being analysed. In some examples, the electrochemical device may be an electrochemical cell or battery. The technique of probing using acoustics in this manner can be applied to a range of battery sizes and cell form factors, including but not limited to pouch cells, prismatic cells, and cylindrical cells. However, the skilled person will understand that other electrochemical devices may be used; for example, but not limited to, fuel cells, galvanic cells, electrolysers, and capacitors. The term “electrochemical devices” may also include electrochemical components, such as but not limited to electrodes. In some examples, the electrochemical material may be, but is not limited to, an electrode material, or other material or component for use in an electrochemical device. In some examples, the acoustic transducer may be an electromagnetic acoustic transducer (EMAT) configured for contactless acoustic analysis of the electrochemical device or electrochemical material, as discussed in relation to the previous aspects of the invention. For example, the at least one electromagnetic acoustic transducer may be configured for acoustic analysis of the electrochemical device or electrochemical material without the use of a couplant between the electromagnetic acoustic transducer and the electrochemical device or electrochemical material. However, the skilled person will understand that, in other examples, other acoustic transducers may be used, such as piezoelectric acoustic transducers for contact acoustic analysis, or laser induced ultrasonic transducers (LIUT). In such examples, the electrochemical device or electrochemical material may be coated with a couplant prior to rastering or scanning the acoustic transducer in contact with a surface of the device or material being studied. In some examples, the electromagnetic acoustic transducer may be a compression wave electromagnetic acoustic transducer configured to induce compressional acoustic waves in the electrochemical device or electrochemical material. This may be advantageous as the applicant has surprisingly found that compression wave electromagnetic acoustic transducers obtain better acoustic measurements for some electrochemical devices, in particular pouch cells, compared to shear wave electromagnetic acoustic transducers. However, the skilled person will understand that, in other examples, the electromagnetic acoustic transducer may be any other electromagnetic acoustic transducer, such as a shear wave electromagnetic acoustic transducer configured to induce shear acoustic waves in the electrochemical device or electrochemical material, including but not limited to a radially polarised shear wave EMAT or an angled shear wave EMAT. The at least one acoustic transducer may be coupled to the housing via the motion controller, such that the motion controller is configured to enable translation and / or rotation of the at least one acoustic transducer. For example, the at least one acoustic transducer may be coupled to a sensor head, wherein the sensor head is coupled to the motion controller configured to enable movement of the sensor head. Alternatively, the motion controller may be configured to enable translation and / or rotation of the electrochemical device or electrochemical material being analysed, for example by controlling movement of a sample bed or platform relative to the at least one acoustic transducer. The motion controller may be configured to enable movement of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to a plurality of degrees of freedom. As such, the motion controller may be a multi-axis motion controller. For example, the motion controller may be configured to enable translation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least three degrees of freedom. Enabling translation according to three degrees of freedom, i.e., translation beyond solely in the xy plane, may be advantageous control the z axis position to allow for repeatable positioning and distance control between the EMAT and the sample under study which may vary in height and / or thickness. Monitoring acoustic signal properties dependent on the z-height will also be related to the properties of the sample and thus may provide additional information about the sample. In addition, when used with contact acoustic transducers, the control relative to the z-axis also allows for control over the pressure applied between the transducer and the sample which is an important variable in controlling the repeatability of the acoustic signal achieved. The motion controller may, additionally or instead, be configured to enable rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least one degree of freedom. As above, the motion controller may be configured to enable rotation of the at least one acoustic transducer, or alternatively the motion controller may be configured to enable translation and / or rotation of the sample being analysed (e.g., the electrochemical device or electrochemical material). In some examples, the motion controller may be configured to enable rotation of both the at least one acoustic transducer and the sample being analysed. In examples wherein the at least one acoustic transducer is coupled to a sensor head, the sensor head may be coupled to the motion controller via a detachable mounting, wherein the detachable mounting is configured to couple to a plurality of interchangeable sensor heads. The plurality of interchangeable sensor heads may each comprise at least one different auxiliary sensor and / or a different acoustic transducer. This may be advantageous to allow multiple acoustic transducers and / or auxiliary sensors to be mounted to the same motion controller system allowing for analysis and probing of electrochemical devices and materials with a range of different transducer types and settings. The detachable mounting may also allow for rapid manual or automated changing of sensor heads. The motion controller may be configured to detect which sensor head is coupled to the detachable mounting and control the translation and / or rotation of the sensor head relative to the electrochemical device or electrochemical material based on the detected sensor head. This may be advantageous to enable the motion control of the sensor head relative to the electrochemical device or electrochemical material, including the position and orientation, to be tailored depending on the requirements of the combination of sensors and transducers present in the sensor head. For example, the controller may be configured to control the position of the sensor head to contact the electrochemical device or sample in the event that the motion controller detects that the attached sensor head comprises a contact acoustic transducer, whereas by contrast, the controller may be configured to control the position of the sensor head relative to the electrochemical device or sample to avoid contact in the event that the motion controller detects that the attached sensor head comprises an electromagnetic acoustic transducer configured for contactless acoustic measurements. The system may further comprise a resilient biasing means coupled between the motion controller and the acoustic transducer, wherein the resilient biasing means is configured to bias the acoustic transducer into a first configuration. This may be advantageous to ensure that the acoustic transducer returns to the same position in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material. The resilient biasing means may additionally be configured to allow movement of the acoustic transducer. This may be advantageous to prevent damage to the acoustic transducer in the event of collision between the acoustic transducer and the electrochemical device or electrochemical material, and / or allow movement of the acoustic transducer to conform to a surface of the electrochemical device or electrochemical material during contact acoustic analysis. In some examples, the resilient biassing means may be coupled between the motion controller and the sensor head. The system may further comprise a force sensor configured to sense an indication offeree applied to the at least one acoustic transducer. The motion controller may be configured to control the position and / or movement of the acoustic transducer relative to the electrochemical device or electrochemical material based on the indication of force sensed by the force sensor. This may be advantageous in order to maintain a constant force between the acoustic transducer and the electrochemical device or electrochemical material for contact sensing applications, and / or to prevent damage to the acoustic transducer in the event of contact or collision between the acoustic transducer and the electrochemical device or electrochemical material. Preventing damage to the electrochemical device or material, such as cells or batteries, during acoustic analysis may be particularly important as too much force or impact can trigger thermal runaway and cause the electrochemical device or material to catch fire or explode. In some examples, the system may comprise an array of acoustic transducers, wherein the acoustic transducers within the array are distributed such that the array is configured to cover at least a portion of a surface of the electrochemical device or electrochemical material. For example, the sensor head may comprise an array of acoustic transducers. This may be advantageous to allow for spatially resolved acoustic measurements, whilst reducing the number of positions the motion controller would have to cover. A plurality of transducers within the array may also be configured to operate as a phased array where beam steering can be utilised. This may be advantageous to focus the acoustic energy and improve the resolution. In some examples, each acoustic transducer comprises a pulse receiver, wherein the pulse receiver is configured to induce the acoustic transducer to induce or generate an acoustic waveform and / or receive at least one of: (i) a transmitted wave, and (ii) a reflected wave. In some examples, the pulse receiver may be multiplexed so that multiple acoustic transducers can be controlled and operated by the same pulse receiver circuit. The acoustic analysis system may further comprise a distance profiling means configured to sense the relative distance of the acoustic transducer from the electrochemical device or electrochemical material. The motion controller may additionally be configured to control the position and / or movement of the acoustic transducer based on the indication of relative distance sensed by the distance profiling means in order to maintain a constant distance between the acoustic transducer and the electrochemical device or electrochemical material during non-contact acoustic analysis, or alternatively to maintain constant contact between the acoustic transducer and the electrochemical device or electrochemical material during contact acoustic analysis. This may be advantageous to increase reliability and repeatability of acoustic analysis measurements and / or to prevent collision between the acoustic transducer and the electrochemical device or electrochemical material. In some examples, the distance profiling means may comprise a laser, such as a laser-based distance profiling system, however the skilled person will understand that other distance profiling means may be used, such as, but not limited to, a low frequency ultrasound system. The acoustic analysis system may further comprise a miniature snap-action switch configured to interrupt movement of the motion controller in the event that force applied to the acoustic transducer exceeds a threshold. This may be advantageous to prevent and reduce damage to the sensor head, including the acoustic transducer, as well as reduce damage to the sample, for example in the event of collision between the acoustic transducer and the electrochemical device or electrochemical material. The acoustic analysis system may further comprise an optical sensor configured for visual inspection of the electrochemical device or electrochemical material. Visual artefacts identified by visual inspection, for example such as crinkling on a pouch cell casing, may be configured to be correlated with the acoustic transducer measurements at the location of the visual artefact. This may be advantageous to correlate any anomalous or irregular surface features with anomalous or irregular acoustic measurements. The acoustic analysis system may further comprise a sensor configured to obtain identification information relating to the electrochemical device or electrochemical material, wherein the identification information is correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. For example, the sensor may comprise an optical sensor configured to read a QR code, barcode, or other visual identifier associated with the electrochemical device or material. Alternatively, or in addition, the sensor may comprise a short-range wireless receiver configured to read a short-range wireless identifier associated with the electrochemical device or material, such as an RFID tag, or similar. The motion controller may additionally be configured to control the position and / or movement of the acoustic transducer based on the identification information relating to the electrochemical device or electrochemical material, for example wherein the identification information may comprise information about a testing regime. The acoustic analysis system may further comprise a Hall sensor and / or an eddy current detection probe, wherein the Hall sensor and / or eddy current detection probe are configured for current mapping of the electrochemical device or electrochemical material, wherein the current mapping measurements are configured to be spatially correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. Preferably, current mapping is conducted during electrochemical testing of the electrochemical device or electrochemical material. The applicant has also found that eddy current systems used for non-destructive testing of metals can also be applied to batteries and cells to detect defects. The motion controller is preferably configured to enable rotation of the Hall sensor and / or an eddy current detection probe relative to the electrochemical device or electrochemical material. This may be advantageous as the resulting signal can be dependent on the orientation of the sensor itself relative to the sample being measured. The acoustic analysis system may further comprise at least one temperature sensor configured to sense an indication of temperature of the electrochemical device or electrochemical material. The temperature sensor may be an important safety feature as an indication that the electrochemical device or electrochemical material is getting too hot may be an indication of cell failure. The system may also comprise a temperature-controlled chamber configured to receive the electrochemical device or electrochemical material for acoustic analysis within the housing, wherein the temperature of the temperature-controlled chamber is configured to be controlled based on the indication of temperature of the electrochemical device or electrochemical material sensed by the at least one temperature sensor. The acoustic analysis system may further comprise an electrochemical test system configured to test the electrochemical device or electrochemical material during acoustic analysis using the at least one acoustic transducer. This may be advantageous to obtain acoustic measurements during electrochemical testing, such as during cycling of an electrochemical device. For example, in cases wherein the electrochemical device is an electrochemical cell or battery, the test system, such as a battery cycler, would enable acoustic measurements to be taken during charge, discharge and / or ageing of the cell or battery. The provision of at least one temperature sensor and an electrochemical test system may provide a synergistic effect as correlation of temperature measurements with electrochemical testing can provide important insights into the electrochemical device or material. For standard testing (e.g., EMAT mapping), the cell temperature would be expected to remain approximately constant, however during electrochemical testing, the cell temperature will be expected to increase by approximately 5 to 10 degrees Celsius, or more. Measuring the temperature changes during electrochemical testing can provide additional information which may also be used to compensate for the effects of the temperature changes on the acoustic measurements. The housing of the acoustic analysis system may further comprise a sample bed, wherein the sample bed is configured to receive the electrochemical device or electrochemical material for acoustic analysis. The sample bed may further comprise at least one sensor configured to sense at least one characteristic of the electrochemical device or electrochemical material within the sample bed. This may be advantageous to enable at least one static sensor relative to the electrochemical device or material. For example, the sample bed may comprise an array of piezoelectric elements configured to receive acoustic signals in transmission mode once the acoustic signals have propagated through the electrochemical device or electrochemical material. This may be advantageous to enable the electromagnetic acoustic transducer to be scanned across the sample surface whilst the array of piezoelectric elements are configured to receive spatially resolved acoustic signals in transmission mode, induced by the electromagnetic acoustic transducer. The array of piezoelectric elements may, additionally or instead, be configured to provide an array of temperature measurements across a surface of the electrochemical device or electrochemical material in the sample bed, however the skilled person will understand that the sample bed may comprise an array of any suitable temperature sensors. The acoustic analysis system may further comprise a controller configured to adjust and / or optimise the acoustic parameters used for acoustic analysis based on acoustic measurements received from the at least one acoustic transducer. Optionally, the controller may be configured to optimise the acoustic parameters used for acoustic analysis additionally based on measurements received from the auxiliary sensors (i.e., non-acoustic transducer sensors) in the acoustic analysis system. The optimisation of the acoustic parameters can be time and labour intensive, requiring specialist knowledge of the equipment and the acoustic techniques used to analyse samples. Thus, providing a controller to control and / or optimise the acoustic parameters based on information from the acoustic transducers, and optionally from other sensors described, may be advantageous to overcome this problem. For example, the controller may be configured to adjust and / or optimise the acoustic parameters based on identification of key features of the acoustic waveform, wherein the controller may be configured to optimise the acoustic parameters based on adjusting at least one acoustic parameter and identifying changes in the key features of the acoustic waveform based on a feedback loop, until these features are optimised. As an example, the controller may be configured to adjust at least one acoustic parameter and monitor changes in the signal-to-noise ratio of the acoustic waveform. The acoustic parameters may then be optimised according to the values or ranges of acoustic parameters which minimise the signal-to-noise ratio. The controller may also be configured to self-calibrate by comparing the variation of an acoustic waveform with parameters on a calibration block of known properties. Furthermore, the controller may be configured to adjust and / or optimise the acoustic parameters based on identification of key features of the acoustic waveform, wherein the controller may be configured to optimise the acoustic parameters based on adjusting at least one of: (i) the distance between the transducer and sample, (ii) the pressure applied by the z height to the transducer in contact with the sample, and (iii) the transducer used, for example by implementing transducer selection. Drawings Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1A shows a perspective view of an example acoustic analysis system for an electrochemical device or electrochemical material. Fig. 1B shows a front view of the example acoustic analysis system of Fig. 1 A. Fig. 2A shows an example sensor head for use with an acoustic analysis system, such as the example acoustic analysis system of Figs. 1A-1B. Fig. 2B shows another example sensor head for use with an acoustic analysis system, such as the example acoustic analysis system of Figs. 1A-1B. Fig. 3 shows another example sensor head, such as the sensor head of Fig. 2B, for use with an acoustic analysis system, such as the example acoustic analysis system of Figs. 1A-1B. Fig. 4 shows a schematic overview of the main components of an acoustic analysis system for an electrochemical device or electrochemical material, such as the example acoustic analysis system of Figs. 1A-1B. Figs. 5A and 5B show a perspective view of an example acoustic analysis system for an electrochemical device or electrochemical material, additionally comprising an enclosed housing. Fig. 5A illustrates the system in an open configuration, and Fig. 5B illustrates the system in a partially closed configuration. Fig. 6 illustrated a schematic overview of a method of use of an example acoustic analysis system, for example such as the example acoustic analysis system of Fig. 1 or Figs. 5A and 5B. Specific description Embodiments of the claims relate to systems and methods for acoustic analysis of electrochemical devices and materials, in particular using an electromagnetic acoustic transducer and / or motion controller. Figs. 1A and 1B show an example acoustic analysis system 100 for an electrochemical device or electrochemical material. The electrochemical device or material being analysed is illustrated by sample S01. The example acoustic analysis system 100 comprises a static frame 102 and a sensor head 106, wherein the sensor head 106 is coupled to the static frame 102 via a moveable frame 103. The static frame 102 may provide a housing configured to receive the electrochemical sample S01 for acoustic analysis. In this example, the static frame 102 has a substantially cube shape, comprising a plurality of horizontal struts 102H and vertical struts 102V forming a cube-like construction. The moveable frame 103 comprises a horizontal strut arranged across the upper surface of the static frame 102, parallel to the front and rear edges of the static frame 102.The moveable frame 103 is configured to move relative to the static frame 102. In particular, the moveable frame 103 is configured to move parallel to the x-direction, between the front and rear edges of the static frame 102, and along the side edges of the static frame 102. The sensor head 106 is coupled to the moveable frame 103 via a moveable sensor mount 108. The moveable sensor mount 108 is configured to move parallel to the y-direction, along the horizontal strut of the moveable frame 103, between the opposing side edges of the static frame 102. In this example, a first system 110 of belts and pulleys is coupled between the sensor mount 108 and moveable frame 103, and a second system 112 of belts and pulleys is coupled between the moveable frame 103 and the static frame 102. The first system 110 of belts and pulleys is configured to translate the sensor mount 108 relative to the moveable frame 103. The second system 112 of belts and pulleys is configured to translate the moveable frame 103 relative to the static frame 102. The first system 110 and the second system 112 of belts and pulleys are coupled to a controller configured to control the motion of the sensor head 106. As such, the controller is configured to control operation of the first system 110 and the second system 112 of belts and pulleys such that the first system 110 and second system 112 of belts and pulleys are configured to cooperate to move the sensor head 106 across the x-y plane, parallel to the upper surface of the static frame 102, such that the sensor head 106 is configured to be translated relative to the static frame 102 and the sample bed 104, parallel to the x- and y- directions. In this example, the controller, and associated control circuitry, is arranged within a control box 120. The controller is configured for control of all parts of the system 100. In some examples, the control box 120 further comprises a wireless communications interface coupled to the controller, wherein the wireless communications interface is configured to enable the controller, and associated system 100, to be controlled remotely, for example by a remote computing device in wireless communication with the wireless communications interface. In the example shown, the control box 120 further comprises a display device 122, such as a display screen. The display device 122 is configured to display the progress of the analysis of a sample by the system 100. Optionally, the control box 120 may be configured to allow user interaction to control the system 100, for example wherein the display device 122 may comprise a touch screen, or the control box 120 may further comprise input devices, such as buttons, to enable the user to control the system 100, by selecting test parameters, etc. The acoustic analysis system 100 also comprises a sample bed 104. The sample bed 104 comprises a plate configured to receive the sample S01. In this example, the sample bed 104 is mounted to the static frame 102 by vertical threaded rods 114. The sample bed 104 is configured to be raised and lowered relative to the static frame 102, parallel to the z-axis, towards and away from the sensor head 106. In particular, the sample bed 104 is configured to be raised and lowered along the threaded rods 114. The sample bed 104 is also coupled to the controller such that the controller is configured to control the translation of the sample bed 104 in the z-direction. In the example shown in Figs. 1A and 1B, the acoustic analysis system 100 comprises a frame system akin to a CoreXY or H-bot 3D printer frame, wherein the sensor head 106 is provided instead of a printer head such that the sensor head 106 is configured to be translated in the x-y plane, and the sample bed 104 is configured to be translated in the z-direction. However, the skilled person will understand that this is merely one example of a suitable frame, and in other examples, other frame configurations may be used, including but not limited to other 3D printer frames, wherein a sensor head is provided instead of a printer head. For example, the example acoustic analysis system 600 shown in Fig. 5A comprises a frame akin to a “Cartesian” or “Rectilinear” printer frame, wherein the sensor head 106 is provided instead of a printer head. For example, the sensor head 106 may be configured to be translated in the z-y plane using a z-y gantry frame 102, and the sample bed 104 may be configured to be translated in the x-direction relative to the z-y gantry frame, or the z-y gantry frame itself may be configured to be translated in the x-direction. In other examples, the acoustic analysis system may instead comprise a frame system (i) configured for movement of the sensor head 106 according to the polar coordinate system, for example wherein the sample bed 104 is configured to be rotated, and the sensor head 106 is configured to be translated in the z-direction relative to the sample bed 104, for example akin to a polar 3D printer frame; (ii) wherein the sensor head 106 is coupled to a robotic arm powered by two motors, configured to translate the sensor head 106 around the x-y plane, and along the z-axis, for example akin to a Selective Compliance Assembly Robot Arm (SCARA) 3D printer frame; (iii) wherein a plurality of arms are attached to vertical rails, and wherein the sensor head 106 is coupled to an end of each arm via hinges, such that the arms are configured for coordinated movement to control the sensor head’s 106 height (z-axis) and location (x- and y-axes) relative to the sample bed 104, for example akin to a delta 3D printer frame; (iv) comprising a conveyor belt, for example wherein the conveyor belt provides the sample bed 104 and is configured to move the sample S01 along the x-axis, whereas the sensor head 106 is configured to be translated in the z-y plane via a gantry frame, robotic arm, or otherwise, for example akin to a belt 3D printer frame; or (v) akin to any other suitable 3D printer frame, wherein a sensor head 106 is provided instead of a printer head, and wherein the print bed is configured to receive the electrochemical device or material. In some examples, a conveyor belt or robotic arm may also be configured to load samples onto the sensor bed, and remove samples after analysis. This may be advantageous to promote automation of analysis, for example in a production line, wherein the conveyor belt or robotic arm may load sample S01 onto the sample bed, and when analysis is complete, remove sample S01, and load a second sample S02 onto the sample bed for analysis, and so on. Returning to the example 100 shown in Figs. 1A and 1B, the sensor head 106 comprises at least one acoustic transducer. In the preferred embodiment, the sensor head 106 comprises at least one electromagnetic acoustic transducer (EMAT). A detailed view of two example sensor heads 106 and sensor mounts 108 are shown in more detail in Figs. 2A, 2B, and 3. The sensor head 106 is preferably configured to be detachable from the sensor mount 108 such that a plurality of different sensor heads 106 comprising different acoustic transducers and / or different auxiliary sensors may be interchanged and reversibly coupled to the same sensor mount 108. As shown in Figs. 2A, 2B, and 3, the sensor mount 108 comprises a plurality of wheels 208. The wheels 208 are configured to engage with the first system 110 of belts and pulleys such that the sensor mount 108 may be moved relative to the moveable frame 103. In this example, the sensor head 106 is arranged beneath the sensor mount 108, such that the sensor head 106 is suspended beneath the sensor mount 108 in use. This may be advantageous to provide the sensor head 106 adjacent to the sample S01 in use, without the sensor mount 108 interfering or inhibiting access between the sensor head 106 and sample S01. The sensor head 106 is configured to be detachably mounted to the sensor mount 108, such that the sensor head 106 is configured to be interchangeable within the system 100. Each sensor head 106 comprises at least one sensor, such as an acoustic transducer or an auxiliary sensor (i.e., a non-acoustic sensor, such as a temperature sensor, distance sensor, etc.). However, preferably, each sensor head 106 comprises at least one acoustic transducer (e.g., an electromagnetic acoustic transducer, or conventional contact acoustic transducer such as a piezoelectric transducer), and at least one auxiliary sensor (i.e., a non-acoustic sensor, such as a temperature sensor, distance sensor, etc.). As such, sensor head 106 may be interchanged within the system 100 according to the desired combination of sensors required for analysis. In some examples, a sensor head may comprise a plurality of interchangeable mounts in order to select the desired combination of acoustic transducer(s) and auxiliary sensor(s) for a sample or application. A controller may be configured to detect which sensor head 106 is coupled to the sensor mount 108, and accordingly which sensors and acoustic transducers are present. The controller is then configured to control the testing program accordingly, based on the interchangeable sensor head 106 and associated transducers and sensors coupled to the sensor mount 108. The sensor mount 108 also comprises at least one resilient biasing means 206, such as a spring, coupled between the sensor head 106 and the sensor mount 108. The resilient biasing means 206 is configured to allow movement of the acoustic transducer to prevent damage to the acoustic transducer and electrochemical device or material in the event of contact between the acoustic transducer and the electrochemical device or material. The resilient biasing means 206 is additionally configured to bias the acoustic transducer into a first configuration, as shown, to return the sensor head 106 to the same position in the event of contact between the acoustic transducer and the sample S01, including collision. The sensor mount 108 also comprises a distance sensor 204 (for example but not limited to a laser-based, contact-based, ultrasound-based, or capacitive distance sensor). The distance sensor 204 is configured to determine the distance between the sensor head 106 and the sample bed 104 and / or the sample being studied S01. Whilst in this example the distance sensor 204 is coupled to the sensor mount 108, the skilled person will understand that in other examples the distance sensor 204 may alternatively be coupled to the sensor head 106. The sensor mount 108 of Fig. 2A additionally comprises a plurality of miniature snap-action switches (or “microswitches”) 202. The microswitches 202 are configured to interrupt movement of the sensor mount 208, controlled by the controller, in the event that force applied to the acoustic transducer exceeds a threshold. This may be advantageous to prevent and reduce damage to the sensor head 106, as well as reduce damage to the sample S01, for example in the event of collision between the senor head 106 and the electrochemical sample S01. However, the skilled person will understand that the microswitches could be replaced with a force sensor, or used in conjunction therewith. Returning to the example 100 shown in Figs. 1A and 1B, the sample bed 104 comprises an array of piezoelectric elements (not shown). The array of piezoelectric elements are configured to receive acoustic signals in transmission mode, wherein the acoustic signals are induced by the sensor head 106. In examples, the array of piezoelectric elements in the sensor bed 104 may, additionally or instead, be configured to emit acoustic waves for conventional contact acoustic analysis, wherein the sample S01 is in contact with the sample bed 104 and array of piezoelectric elements. The sample bed 104 may also comprise at least one auxiliary sensor (i.e., a non-acoustic sensor), for example such as an array of temperature sensors, and / or current sensors. An overall schematic diagram of an example acoustic analysis system 100 illustrating the constituent components is shown in Fig. 4. The sensor head 106 comprises an electromagnetic acoustic transducer (EMAT) 406 configured for contactless acoustic measurements. In the example shown, the sensor head 106 may additionally comprise a contact acoustic transducer 408, such as a piezoelectric transducer, configured for contact acoustic measurements. However, the skilled person will understand that in other examples, a sensor head 106 may comprise either an electromagnetic acoustic transducer (EMAT) 406, or a conventional contact acoustic transducer 408. The electromagnetic acoustic transducer (EMAT) 406 is coupled to an EMAT pulse receiver 424. The EMAT pulse receiver 424 is configured to receive either the transmitted or reflected acoustic wave induced by the EMAT 406. The pulse receiver 424 may also be configured to control the EMAT 406 to induce the acoustic waveform within the sample S01 and control the acoustic parameters such as, but not limited to, at least one of gain, pulse intensity, pulse shape, pulse length, receiver gain, filtering, etc. This may be achieved by communicating via a controller 432. Similarly, any contact acoustic transducers 408 are coupled to a pulse receiver 428. The pulse receiver 428 is configured to receive either the transmitted or reflected acoustic wave generated by the contact acoustic transducers 408. The pulse receiver 428 may also be configured to control the contact acoustic transducers 408 to induce the acoustic waveform and control the acoustic parameters such as, but not limited to, at least one of gain, pulse intensity, pulse shape, pulse length, receiver gain, filtering, etc. Instead of an EMAT pulse receiver 424, the system 100 may alternatively comprise an EMAT conversion box 426 (or “EMAT adapter”) which is in turn coupled to a conventional acoustic pulse receiver 428. The EMAT conversion box 426 may allow the pulse receiver 428 to be configured for use with both the EMAT 406, and any contact acoustic transducers 406. The controller 432 is configured to control the position and motion of the sensor head 106 relative to the sample S01. The controller 432 is also configured to control the operation of the acoustic transducers 406 and 408, as well as any additional auxiliary sensors (i.e., non-acoustic sensors). The sensor head 106 in this example comprises a plurality of auxiliary sensors. For example, the sensor head 106 may further comprise a temperature sensor 410. The temperature sensor 410 may be a non-contact temperature sensor, such as an infra-red sensor. The addition of temperature sensors may allow for accurate monitoring of the temperature of the sample S01, as well as the testing environment. This can be used as an additional safety measure to ensure measurements are done in a safe manner and that the sample S01 is not heated too high or too rapidly. The scanning of a single point temperature measurement across the surface of the sample S01, the implementation of several temperature sensors in an array, or a thermal imaging camera, may also allow for a temperature map of the cell to be developed. Temperature can influence the material properties of the sample S01 under study and, as such, temperature mapping can provide important information about the sample S01, alongside acoustic measurements. In addition, temperature mapping can also provide important information about the functioning of an operating device, such as sample S01, during testing. Whilst in this example, the temperature sensor 410 is shown as being coupled to the sensor head 106, the skilled person will understand that, alternatively or in addition, the system 100 may comprise at least one temperature sensor not coupled to the sensor head 106. For example, the system 100 may comprise at least one temperature sensor, such as a thermistor or thermocouple, or an array of temperature sensors, arranged in the sample bed 104. Temperature sensors within the sample bed 104 may be advantageous as they may be configured to contact the sample S01 during use. The system 100 also comprises a temperature-controlled element 402, such as a heater element and / or cooling element. The temperature-controlled element 402 may be coupled to the sample bed 104, or otherwise within a sample chamber configured to receive the sample S01, such as the external housing 506, as shown in Figs. 5A and 5B. The controller 432 is configured to control operation of the temperature-controlled element 402. This may be advantageous to control the temperature of the sample S01 prior to and / or during acoustic analysis, particularly because temperature can influence the material properties of the sample S01 under study. The temperature of the temperature-controlled element 402 may be configured to be controlled by the controller 432 based on the indication of temperature from the temperature sensor 410, for example based on a temperaturecontrol feedback loop to obtain a required or a stable temperature. The sensor head 106 may also comprise a distance sensor 412, for example but not limited to a laser-based sensor, contact-based sensor, ultrasound-based sensor, or capacitive distance sensor. The distance sensor 204 is configured to determine the distance between the sensor head 106 and the sample bed 104 and / or the sample being studied S01. The distance sensor 412 may be provided instead of, or in addition to, distance sensor 204 coupled to the sensor mount 108. This distance measurement can be used as a safety provision to prevent unintentional collision and impact between the sample S01 and the sensor head 106. Additionally, the distance measurement may be used to generate a height profile of the sample S01 under study by scanning the distance sensor 204 across the surface of the sample S01. The height profile may be used to determine the height position of the sensor head 106 during scanning to ensure that the distance between the acoustic transducer and the sample S01 is constant regardless of the changing geometry of the sample S01. The height profile of the sample can also be used to determine the size of the sample S01 in the xy-plane, the height of the sample S01 in the z direction, the location and position of the sample S01 on the sample bed 104, and / or the angle at which the sample S01 is placed onto the sample bed 104. The acoustic transducer and / or sensor head can be positioned and / or rotated accordingly to accommodate this. The acoustic waveform obtained during acoustic analysis is dependent on the structure of the sample S01, the sample’s material properties and the thickness of the sample. As such, the combination of the height profile obtained by a distance sensor and the acoustic waveform may allow more accurate information about the material properties of the sample to be obtained by accounting for the effects of sample thickness, which is not obtainable through ultrasound alone. By obtaining the height / thickness of the sample S01, a predicted time of flight for an ultrasound may also be determined. More accurate predictions may be possible additionally based on the composition or material of the sample S01. This information can be fed into an automated optimisation sub-system for control of the acoustic parameters, with the system able to focus on the desired region, extracting only the required data and improving the speed of acquisition and optimisation. The sensor head 106 may further comprise an optical sensor 414 configured for visual inspection of the sample S01. Visual artefacts identified by visual inspection, for example such as crinkling on a pouch cell casing, may be configured to be correlated with the acoustic transducer measurements at the location of the visual artefact. The sensor head 106 may further comprise a Hall effect sensor 416 configured to detect the presence and magnitude of a magnetic field for current mapping of the sample. Additionally or instead, the sensor head 106 may comprise an eddy current sensor 418 configured for current mapping of the sample and / or for non-destructive defect mapping of the sample, wherein the measurements are configured to be spatially correlated with the acoustic transducer measurements of the sample. In some examples, the eddy current sensor 418 may be provided by the coil of the electromagnetic acoustic transducer 406. The sensor head 106 may, additionally or instead, comprise any other sensors 420 to 420N configured to sense properties or characteristics of an electrochemical device or material. Combining multiple sensor readings together allows for the collection of data that is more insightful and accurate than when the data is collected in isolation, this is particularly important when a cell is under operating conditions where factors such as cell thickness and temperature will impact acoustic readings related to state of charge (SoC) or health (SoH) changes. The measurements obtained by the auxiliary sensors are obtained by a sensor interface 430. The data obtained by the sensor interface 430 can either be processed locally by the controller 432, or be sent to a remote server 434 for processing and analysis, such as a cloud platform. For example, the sensor interface 430 may be configured to convert signals from the sensors which may be digital or analogue, of varying amplitudes and types into signals that can be processed and understood by the controller 432. The process electronics, such as the EMAT pulse receiver 424, the EMAT adapter 426, the pulse receiver 428, the sensor interface 430, and the controller 432, may be arranged within the enclosed control box 120 illustrated in Figs. 1A and 1B. This may be advantageous to protect the control electronics. For example, the control box 120 may be configured to protect the electronics from failure of the electrochemical samples during analysis, including for example thermal runaway of an electrochemical cell. However, the skilled person will understand that in other examples, at least a portion of the process electronics may be located elsewhere in the system, outside of the enclosed control box 120. The system 100 also comprises an electrochemical test system 404, such as a potentiostat / galvanostat, or connections for the system 100 to be connected to an electrochemical test system. The controller 432 is configured to control operation of the electrochemical test system 404. The electrochemical test system 404 may allow the sample S01, such as a cell or battery, to be formed, tested, cycled and / or aged while being carefully studied using the sensors coupled to the sensor head 106, including the EMAT 406 and / or contact acoustic transducer 408, allowing for the acoustic signature of the sample S01 to be mapped as it is operated. The system 100 may be configured for electrochemical impedance spectroscopy (EIS) to obtain measurements relating to the electrochemical performance of a sample S01, or cell. Alternatively, or in addition, the system 100 may be configured for galvanostatic intermittent titration techniques (GITT) and / or Potentiostatic Intermittent Titration Technique (PITT). However, the EIS, GITT and PITT electrochemical testing techniques typically obtain a single overall reading of the whole cell or sample as an average is obtained. By combining this electrochemical testing techniques with spatially resolved acoustic measurements, and auxiliary sensor measurements, additional information about the cell properties can be obtained. For example, coupling a temperature map with electrochemical testing adds valuable insight into the operation of a cell. Furthermore, combination of these techniques with acoustic analysis unlocks a new level of analysis beyond anything obtainable with current methods allowing for state of charge (SoC) and state of health (SoH) mapping across the surface of the cell coupled with electrochemical test measurements. The interchangeable sensor head 160 is coupled to a controller that controls the motion, position, and orientation of the sensor head 160 relative to the static frame 102 and sample S01. The electrochemical test system 404 and all auxiliary sensors are also coupled to the controller to ensure that all measurements are precisely correlated according to the time and position relative to the sample S01 that they were obtained. This close correlation and precise motion control opens up the possibility of new analytical insight and techniques based on the combination of multiple sensors of the system, in many cases providing spatially resolved measurements simultaneously. The number and selection of sensors and / or interchangeable sensor heads 106 included in each system 100 is designed to be flexible so that the system can be optimised for the analysis and processes required by its intended use. The optimisation of the acoustic parameters can be time and labour intensive, requiring specialist knowledge of the equipment and the acoustic techniques used to analyse samples. To address this, an automated optimisation sub-system is provided. This optimisation process is based on the identification of key features of the acoustic waveform and the alteration of parameters and transducers until these features are optimised. The system may also be configured to self-calibrate by comparing the variation of an acoustic waveform with parameters on a calibration block included as part of the system 100. For example, the optimisation process may be based on the identification of at least the ‘back wall echo’ or echo signal which is related to the ultrasound signal that has passed through the sample and been reflected off the back of the sample. Peaks prior to this ‘echo’ peak are related to the reflections from the internal layered structure of the sample. In general, the first echo peak gives an average of the whole sample, whereas peaks at lower reflection times (times of flight) are from within the internal structure of the sample. Thus, the optimisation process may be dependent on which of these structures are of interest for analysis in order to optimise accordingly for different peaks. In use, the sample S01 is received by the sample bed 104 and the system 100 performs contactless acoustic analysis on the sample S01 using an electromagnetic acoustic transducer (EMAT) 406. An example method 600 of use is shown in Fig. 6. The method 600 comprises obtaining a first acoustic measurement (602) at a first position relative to the sample S01, using an electromagnetic acoustic transducer 406. The method 600 then comprises moving the electromagnetic acoustic transducer 406 to a second position relative to the sample S01 (604), for example wherein moving the electromagnetic acoustic transducer 406 is implemented by a controller which sends a control signal causing the sensor head 106 to be moved relative to the sample S01. Moving the electromagnetic acoustic transducer 406 may comprise translating and / or rotating the electromagnetic acoustic transducer 406 relative to the surface of the electrochemical sample S01, using the controller. A second acoustic measurement is then obtained at the second position using the electromagnetic acoustic transducer 406 (606). Steps 604 and 606 may be repeated for a series of positions relative to the surface of the sample S01, scanning the electromagnetic acoustic transducer 406 across a surface of the sample S01 and obtaining acoustic measurements at discrete points, such that acoustic measurements are obtained for an array of spatially resolved positions relative to the sample S01 surface. The resolution of the acoustic scan can be precisely controlled by controlling the number of points sampled across the surface of the sample S01. For most applications and major defects, a rapid scan with a relatively low resolution is sufficient to detect the majority of anomalies and defects. By increasing the number of acoustic readings taken across the surface of the sample S01 and reducing the distance between readings, the resolution can be increased significantly. The resolution is only limited by the precision of the motion control system that is employed to control the position of the sensor head 106 relative to the sample S01. For each contactless acoustic measurement, the electromagnetic acoustic transducer 406 obtains the acoustic measurements by generating Lorentz force, wherein the Lorentz force is configured to induce acoustic waves in the electrochemical sample S01. For example, the electromagnetic acoustic transducer 406 provides a first magnetic field applying a current to an electrical coil of the electromagnetic acoustic transducer 406, and a second magnetic field using a magnet of the electromagnetic acoustic transducer 406. The first magnetic field is configured to induce eddy currents in the electrochemical sample S01, and the second magnetic field is configured to interact with the induced eddy currents to generate the Lorentz force, wherein the Lorentz force is configured to induce an acoustic wave in the electrochemical sample S01. The acoustic wave propagates through the electrochemical sample S01 and is then measured by the electromagnetic acoustic transducer 406. Measuring the acoustic wave comprises measuring the induced current and / or potential difference in a receiving coil of the electromagnetic acoustic transducer 406, wherein the current of the receiving coil is configured to be induced by contactless interaction between the acoustic wave propagating through the electrochemical sample S01 in the presence of the second magnetic field. The receiving coil may be the same as or separate to the electrical coil configured to a first magnetic field, for example depending on whether the system is configured for transmission or reflection mode measurements. In particular, the electromagnetic acoustic transducer 406 may be a compression wave electromagnetic acoustic transducer, wherein the electromagnetic acoustic transducer 406 is configured to induce compressional acoustic waves in the electrochemical sample S01. This may be advantageous as it has been surprisingly found that compression wave electromagnetic acoustic transducers obtain better acoustic measurements for some electrochemical devices, in particular pouch cells, compared to shear wave electromagnetic acoustic transducers. However, the skilled person will understand that, in other examples, the electromagnetic acoustic transducer may be any other electromagnetic acoustic transducer, such as a shear wave electromagnetic acoustic transducer configured to induce shear acoustic waves in the electrochemical device or electrochemical material, including but not limited to a radially polarised shear wave EMAT or an angled shear wave EMAT. The EMAT stimulus signals can be varied by varying amplitudes and frequencies. A measurement may also be composed of a number of repeat stimuli of varying amplitude. This may be implemented to advantageously overcome parts of the acoustic response becoming saturated. In particular, multiple scans may also be performed with varying amplitude so that different parts of the electrochemical device structure can be examined so as to avoid signal saturation. The multi-pulse (amplitude) measurement may also provide enhanced insight about the entire battery structure. Once at least one acoustic measurement has been obtained, the method 600 further comprises performing signal processing (608) to determine at least one characteristic of the electrochemical sample S01. Example signal processing methods may include, but are not limited to, at least one of:(i) peak identification;^) peak quantification;(iii) multi-peak identification and / or quantification; (iv) total energy measurements; (v) Fourier transform analysis, or equivalent analysis in the spectral domain; and / or (vi) comparative analysis against a baseline measurement. Preferably, multiple acoustic measurements may be taken at each point. During signal processing, the multiple acoustic measurements may be averages to improve to signal-to-noise ratio. This may be particularly advantageous to EMAT measurements as the measurement signal can be relatively weak, for example compared to conventional contact piezoelectric acoustic measurements. Preferably, the sample S01 undergoes electrochemical testing using an electrochemical testing system, such as a battery cycler, whilst performing acoustic analysis according to the method 600. This may be advantageous to obtain acoustic measurements during cycling of the electrochemical device. For example, in cases wherein the electrochemical device is an electrochemical cell or battery, the method may further comprise charging and / or discharging the cell or battery using a cell cycler system whilst performing acoustic analysis. This could enable acoustic measurements to be taken during charge, discharge and / or ageing of the cell or battery. Combined electrochemical testing and acoustic analysis can give significantly more detailed information about the design, performance and state of a cell or material under study. Figs. 5A and 5B show a perspective view of another example acoustic analysis system 500 for an electrochemical device or electrochemical material. This system 500 comprises a static frame 102 and a sensor head 106, wherein the sensor head 106 is coupled to the static frame 102 via a moveable frame 103. In this example, the static frame 102 comprises a gantry frame, comprising two vertical struts coupled by a horizontal strut. The static frame 102 is configured to be parallel to the z-y plane. The moveable frame 103 comprises a horizontal strut arranged across the gantry provided by the static frame 102, parallel to the y-axis. The moveable frame 103 is configured to move relative to the static frame 102. In particular, the moveable frame 103 is configured to move parallel to the z-direction, along the vertical struts of the static frame 102. The sensor head 106 is coupled to the moveable frame 103 via the moveable sensor mount 108. The moveable sensor mount 108 is configured to move parallel to the y-direction, along the horizontal strut of the moveable frame 103, between the opposing vertical struts of the static frame 102. In this example, a first system of belts and pulleys is coupled between the sensor mount 108 and moveable frame 103, and a second system of belts and pulleys is coupled between the moveable frame 103 and the static frame 102. The first system of belts and pulleys is configured to translate the sensor mount 108 relative to the moveable frame 103. The second system of belts and pulleys is configured to translate the moveable frame 103 relative to the static frame 102. The first system and the second system of belts and pulleys are coupled to a motion controller. The controller is configured to control operation of the first system and the second system of belts and pulleys such that the first system 110 and second system 112 of belts and pulleys are configured to cooperate to move the sensor head 106 across the z-y plane, parallel to the plane of the static frame 102, such that the sensor head 106 is configured to be translated relative to the static frame 102 and the sample bed 104, parallel to the x- and y- directions. The acoustic analysis system 100 also comprises a sample bed 104. The sample bed 104 comprises a plate configured to receive the sample S01. In this example, the sample bed 104 is mounted to a second static frame 504. The second static frame comprises a second horizontal strut, arranged perpendicular to the first static gantry frame 102, and parallel to the x-direction The sample bed 104 is configured to be moved relative to the second static frame 504, parallel to the x-axis, towards and away from the sensor head 106. In particular, a third system of belts and pulleys is coupled between the sample bed 104 and the second static frame 504. The third system of belts and pulleys is also coupled to the motion controller. The controller is configured to control the translation of the sample bed 104 in the x-direction. As such, the third system of configured to translate the sample bed 104 relative to the second static frame 504, controlled by the motion controller. The system 500 further comprises an external housing 506. In this example, the external housing comprises a base portion 507 and a lid portion 508. The static frames 102 and 504 are coupled to the base portion 507 of the housing. In this example, the lid portion 508 is hinged relative to the base portion 507. Fig. 5A shows the lid portion 508 in the open configuration relative to the base portion 507, revealing the sensor head 106 and static frame 102, whereas Fig. 5A shows the lid portion 508 in the closed configuration relative to the base portion 507. In the closed configuration, the sensor head 106 is configured to be arranged within the external housing 506. The external housing 506 may be advantageous to control the sample testing environment, in particular for example for temperature control. In the example shown, the lid portion 508 further comprises a door 509. The door 509 is arranged on the front surface of the lid portion 508, adjacent to the sample bed 104. As shown in Fig. 5B, when the lid portion 508 is in the closed configuration relative to the base portion 507, the door 509 is configured to be transitioned between an open and a closed configuration. In the open configuration, the door 509 may permit access to the interior of the external housing 506, without requiring the entire lid portion 506 to be opened. This may be advantageous, for example for loading a sample S01 into the system 500. This may also minimise heat loss when using a temperature-controlled environment within the housing 506 during sample loading. The door 509 further comprises a window 510. This may be advantageous such that, even when the door 509 is closed, a user can still observe the system performing acoustic analysis, and other testing, within the external housing 506. Whilst the window 510 is provided in the door 509 in this example, the skilled person will understand that in other examples, the window 510 may be provided elsewhere on the external housing 506, for example in a side wall or upper wall of the lid portion 508. In use, the door 509 is opened by control of the controller and the sample bed 104 is positioned to extend through the aperture of the open door 509. A sample S01, such as an electrochemical cell, is then loaded onto the sample bed 104. The sample bed 104 and sample S01 are then subsequently withdrawn by the controller into the external housing 506 for acoustic analysis. The door 509 is then closed by the controller to enclose the testing environment. As such, loading of the sample S01 into the system 500 may be fully automated. The controller is then configured to actuate the sensor head 106 and moveable frame 103 to perform acoustic analysis, and other auxiliary sensing functionality, as described above in relation to Fig. 6. It will be appreciated from the discussion above that the embodiments shown in the Figures are merely exemplary, and include features which may be generalised, removed, or replaced as described herein and as set out in the claims. In the context of the present disclosure other examples and variations of the apparatus and methods described herein will be apparent to a person of skill in the art. NUMBERED STATEMENTS OF INVENTION: 1. An acoustic analysis system for an electrochemical device or electrochemical material, the system comprising: a housing, configured to receive an electrochemical device or electrochemical material for acoustic analysis; and at least one electromagnetic acoustic transducer configured for contactless acoustic analysis of the electrochemical device or electrochemical material received by the housing. 2. The acoustic analysis system of statement 1 further comprising a motion controller configured to enable translation and / or rotation of the at least one electromagnetic acoustic transducer relative to the electrochemical device or electrochemical material received by the housing. 3. An acoustic analysis system for an electrochemical device or electrochemical material, the system comprising: a housing, configured to receive an electrochemical device or electrochemical material for acoustic analysis; and at least one acoustic transducer configured for acoustic analysis of an electrochemical device or electrochemical material; and a motion controller configured to enable translation and / or rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material received by the housing. 4. The acoustic analysis system of statement 3 wherein the acoustic transducer is an electromagnetic acoustic transducer configured for contactless acoustic analysis of the electrochemical device or electrochemical material. 5. The acoustic analysis system of any of statements 1 to 2, or 4,wherein the at least one electromagnetic acoustic transducer is configured for acoustic analysis of the electrochemical device or electrochemical material without the use of a couplant between the electromagnetic acoustic transducer and the electrochemical device or electrochemical material. 6. The acoustic analysis system of any of statements 2 to 5 wherein the motion controller is configured to enable movement of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to a plurality of degrees of freedom. 7. The acoustic analysis system of statement 6 wherein the motion controller is configured to enable translation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least three degrees of freedom. 8. The acoustic analysis system of any of statements 2 to 7 wherein the motion controller is configured to enable rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to at least one degree of freedom. 9. The acoustic analysis of statements 2 to 8 wherein the at least one acoustic transducer is coupled to a sensor head, and wherein the sensor head is coupled to the motion controller configured to enable movement of the sensor head, wherein the motion controller is a multi-axis motion controller. 10. The acoustic analysis system of any of statements 2 to 9 wherein: the at least one acoustic transducer is coupled to a sensor head; and the sensor head is coupled to the motion controller via a detachable mounting, wherein the detachable mounting is configured to couple to a plurality of interchangeable sensor heads, wherein the plurality of interchangeable sensor heads each comprise at least one different sensor and / or a different acoustic transducer. 11. The acoustic analysis system of statement 10 wherein the motion controller is configured to detect which sensor head is coupled to the detachable mounting and control the translation and / or rotation of the sensor head relative to the electrochemical device or electrochemical material based on the detected sensor head. 12. The acoustic analysis system of any of statements 2 to 11 further comprising a resilient biasing means coupled between the motion controller and the at least one acoustic transducer, wherein the resilient biasing means is configured to bias the at least one acoustic transducer into a first configuration to ensure that the acoustic transducer returns to the same position in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material. 13. The acoustic analysis system of any of statements 2 to 12 further comprising a resilient biasing means coupled between the motion controller and the at least one acoustic transducer, wherein the resilient biasing means is configured to allow movement of the acoustic transducer to prevent damage to the acoustic transducer in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material and / or allow movement of the acoustic transducer to conform to a surface of the electrochemical device or electrochemical material. 14. The acoustic analysis system of any preceding statement further comprising a force sensor configured to sense an indication offeree applied to the at least one acoustic transducer; wherein the motion controller is configured to control the position of the acoustic transducer relative to the electrochemical device or electrochemical material based on the indication of force sensed by the force sensor in order to maintain a constant force between the acoustic transducer and the electrochemical device or electrochemical material and / or prevent damage to the acoustic transducer in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material. 15. The acoustic analysis system of any preceding statement comprising an array of acoustic transducers, wherein the acoustic transducers within the array are distributed such that the array is configured to cover at least a portion of a surface of the electrochemical device or electrochemical material to allow for spatially resolved acoustic measurements. 16. The acoustic analysis system of any preceding statement wherein each acoustic transducer comprises a pulse-receiver, wherein the pulse-receiver is configured to induce the acoustic transducer to generate an acoustic waveform and / or receive at least one of: (i) a transmitted wave, and (ii) a reflected wave. 17. The acoustic analysis system of any preceding statement further comprising a distance profiling means configured to sense the relative distance of the acoustic transducer from the electrochemical device or electrochemical material, and wherein the motion controller is configured to control the position of the acoustic transducer based on the indication of relative distance sensed by the distance profiling means in order to maintain a constant distance between the acoustic transducer and the electrochemical device or electrochemical material during acoustic analysis and / or to prevent collision between the acoustic transducer and the electrochemical device or electrochemical material. 18. The acoustic analysis system of any preceding statement further comprising a miniature snap-action switch configured to interrupt movement of the motion controller in the event that force applied to the acoustic transducer exceeds a threshold. 19. The acoustic analysis system of any preceding statement further comprising an optical sensor configured for visual inspection of the electrochemical device or electrochemical material, wherein visual artefacts on the electrochemical device or electrochemical material identified by visual inspection are configured to be correlated with the acoustic transducer measurements at the location of the visual artefact. 20. The acoustic analysis system of any preceding statement further comprising a sensor configured to obtain identification information relating to the electrochemical device or electrochemical material, wherein the identification information is correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. 21. The acoustic analysis system of any preceding statement further comprising at least one of: (i) a Hall sensor; and / or (ii) an eddy current probe; configured for current mapping of the electrochemical device or electrochemical material, wherein the current mapping measurements are configured to be spatially correlated with the acoustic transducer measurements of the electrochemical device or electrochemical material. 22. The acoustic analysis system of any preceding statement, further comprising: at least one temperature sensor configured to sense an indication of temperature of the electrochemical device or electrochemical material; and a temperature-controlled chamber configured to receive the electrochemical device or electrochemical material for acoustic analysis within the housing; wherein the temperature of the temperature-controlled chamber is configured to be controlled based on the indication of temperature of the electrochemical device or electrochemical material sensed by the at least one temperature sensor. 23. The acoustic analysis system of any preceding statement further comprising an electrochemical test system configured to test the electrochemical device or electrochemical material during acoustic analysis using the at least one acoustic transducer. 24. The acoustic analysis system of any preceding statement wherein the housing comprises a sample bed, wherein the sample bed is configured to receive the electrochemical device or electrochemical material for acoustic analysis, and wherein the sample bed further comprises at least one sensor configured to sense at least one characteristic of the electrochemical device or electrochemical material within the sample bed. 25. The acoustic analysis system of statement 24 wherein the sample bed further comprises an array of piezoelectric elements configured to receive acoustic signals in transmission mode once the acoustic signals have propagated through the electrochemical device or electrochemical material. 26. The acoustic analysis system of any of statements 1 to 2, or 4 to 25, wherein the electromagnetic acoustic transducer is a compression wave electromagnetic acoustic transducer. 27. A method of acoustic analysis for an electrochemical device or electrochemical material, the method comprising performing acoustic analysis on an electrochemical device or electrochemical material using an electromagnetic acoustic transducer, wherein the electromagnetic acoustic transducer is configured for contactless acoustic analysis by generating Lorentz force, wherein the Lorentz force is configured to induce acoustic waves in the electrochemical device or electrochemical material. 28. The method of statement 27 wherein performing acoustic analysis using an electromagnetic acoustic transducer comprises: providing a first magnetic field using an electrical coil of the electromagnetic acoustic transducer; providing a second magnetic field using a magnet of the electromagnetic acoustic transducer, wherein the first magnetic field and the second magnetic field are configured to interact to generate Lorentz force, wherein the Lorentz force is configured to induce an acoustic wave in the electrochemical device or electrochemical material; and measuring the acoustic wave from the electrochemical device or electrochemical material using the electromagnetic acoustic transducer to determine at least one characteristic of the electrochemical device or electrochemical material. 29. The method of statement 28 wherein measuring the acoustic wave comprises measuring the induced current and / or potential difference in a receiving coil of the electromagnetic acoustic transducer, wherein the current of the receiving coil is configured to be induced by contactless interaction between the acoustic wave propagating through the electrochemical device or electrochemical material in the presence of the second magnetic field. 30. The method of statement 28 or 29 wherein providing the first magnetic field comprises applying a current to the electrical coil of the electromagnetic acoustic transducer, wherein the first magnetic field is configured to induce eddy currents on a surface of the electrochemical device or electrochemical material; and wherein the second magnetic field is configured to interact with the induced eddy currents to generate the Lorentz force. 31. The method of any of statements 27 to 30 wherein performing acoustic analysis using an electromagnetic acoustic transducer comprises: scanning the electromagnetic acoustic transducer across a surface of the electrochemical device or electrochemical material; and performing acoustic analysis at discrete points across the surface of the electrochemical device or electrochemical material. 32. The method of statement 31 wherein scanning the electromagnetic acoustic transducer comprises translating and / or rotating the electromagnetic acoustic transducer relative to the surface of the electrochemical device or electrochemical material using a multi-axis motion controller. 33. The method of any of statements 27 to 32 wherein the acoustic wave is configured to be measured in reflection mode relative to the electrochemical device or electrochemical material. 34. The method of statement 33 wherein the electrical coil of the electromagnetic acoustic transducer configured to generate the first magnetic field is also configured to be the receiving coil. 35. The method of any of statements 27 to 32 wherein the acoustic wave is configured to be measured in transmission mode relative to the electrochemical device or electrochemical material. 36. The method of any of statements 27 to 35 further comprising performing signal processing on the received acoustic wave to determine at least one characteristic of the electrochemical device or electrochemical material or electrochemical material, wherein performing signal processing comprises at least one of: (i) peak identification; (ii) peak quantification; (iii) multi-peak identification and / or quantification; (iv) total energy measurements; (v) Fourier transform analysis, or equivalent analysis in the spectral domain; and / or (vi) comparative analysis against a baseline measurement. 37. The method of any of statements 27 to 36 further comprising testing the electrochemical device or electrochemical material using an electrochemical testing system whilst performing acoustic analysis. 38. The method of statement 37, wherein the electrochemical device or electrochemical material is an electrochemical cell, the method further comprising charging and / or discharging the cell using a cell cycler system whilst performing acoustic analysis. 39. The method of any of statements 27 to 38, wherein the electromagnetic acoustic transducer is a compression wave electromagnetic acoustic transducer configured to induce compressional acoustic waves in the electrochemical device or electrochemical material. 40. A computer readable non-transitory storage medium comprising a program for a computer configured to cause a processor to perform the method of any of statements 27 to 39.

Claims

1. An electrochemical device or electrochemical material acoustic analysis system, the system comprising:a housing, configured to receive an electrochemical device or electrochemical material for acoustic analysis;at least one acoustic transducer configured for acoustic analysis of an electrochemical device or electrochemical material;a motion controller configured to enable translation and / or rotation of the at least one acoustic transducer relative to the electrochemical device or electrochemical material received by the housing; anda force sensor configured to sense an indication of force applied to the at least one acoustic transducer;wherein the motion controller is configured to control the position of the acoustic transducer relative to the electrochemical device or electrochemical material based on the indication of force sensed by the force sensor.

2. The acoustic analysis system of claim 1 wherein the acoustic transducer is a piezoelectric acoustic transducer configured for contact acoustic analysis of the electrochemical device or electrochemical material.

3. The acoustic analysis system of any preceding claim, further comprising a liquid, gel, or solid couplant.

4. The acoustic analysis system of any preceding claim wherein the motion controller is configured to enable movement of the at least one acoustic transducer relative to the electrochemical device or electrochemical material according to a plurality of degrees of freedom.

5. The acoustic analysis of any preceding claimwherein the at least one acoustic transducer is coupled to a sensor head, and wherein the sensor head is coupled to the motion controller configured to enable movement of the sensor head, wherein the motioncontroller is a multi-axis motion controller.

6. The acoustic analysis system of any preceding claim wherein:the at least one acoustic transducer is coupled to a sensor head; andthe sensor head is coupled to the motion controller via a detachable mounting, wherein the detachable mounting is configured to couple to a plurality of interchangeable sensor heads, wherein the plurality of interchangeable sensor heads each comprise at least one different sensor and / or a different acoustic transducer.

7. The acoustic analysis system of claim 6 wherein the motion controller is configured to detect which sensor head is coupled to the detachable mounting and control the translation and / or rotation of the sensor head relative to the electrochemical device or electrochemical material based on the detected sensor head.

8. The acoustic analysis system of any preceding claim further comprising a resilient biasing means coupled between the motion controller and the at least one acoustic transducer, wherein the resilient biasing means is configured to bias the at least one acoustic transducer into a first configuration to ensure that the acoustic transducer returns to the same position in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material.

9. The acoustic analysis system of any preceding claim further comprising a resilient biasing means coupled between the motion controller and the at least one acoustic transducer, wherein the resilient biasing means is configured to allow movement of the acoustic transducer to prevent damage to the acoustic transducer in the event of contact between the acoustic transducer and the electrochemical device or electrochemical material and / or allow movement of the acoustic transducer to conform to a surface of the electrochemical device or electrochemical material.

10. The acoustic analysis system of any preceding claim comprising an array of acoustic transducers, wherein the acoustic transducers within the array are distributed such that the array is configured to cover at least a portion of a surface of the electrochemical device or electrochemical material to allow for spatially resolved acousticmeasurements.

11. The acoustic analysis system of any preceding claim wherein each acoustic transducer comprises a pulse-receiver, wherein the pulse-receiver is configured to induce the acoustic transducer to generate an acoustic waveform and / or receive at least one of: (i) a transmitted wave, and (ii) a reflected wave.

12. The acoustic analysis system of claim 11, wherein the pulse-receiver is multiplexed.

13. The acoustic analysis system of any preceding claim further comprising a distance profiling means configured to sense the relative distance of the acoustic transducer from the electrochemical device or electrochemical material, andwherein the motion controller is configured to control the position of the acoustic transducer based on the indication of relative distance sensed by the distance profiling means in order to maintain a constant distance between the acoustic transducer and the electrochemical device or electrochemical material during acoustic analysis and / or to prevent collision between the acoustic transducer and the electrochemical device or electrochemical material.

14. The acoustic analysis system of any preceding claim further comprising a miniature snap-action switch configured to interrupt movement of the motion controller in the event that force applied to the acoustic transducer exceeds a threshold.

15. The acoustic analysis system of any preceding claim wherein the housing comprises a sample bed, wherein the sample bed is configured to receive the electrochemical device or electrochemical material for acoustic analysis, and wherein the sample bed further comprises at least one sensor configured to sense at least one characteristic of the electrochemical device or electrochemical material within the sample bed.

16. The acoustic analysis system of claim 20 wherein the sample bed further comprises an array of piezoelectric elements configured to receive acoustic signals in transmission mode once the acoustic signals have propagated through the electrochemical device orelectrochemical material.

17. The acoustic analysis system of any preceding claim, further comprising a controller configured to self-calibrate by comparing the variation of an acoustic waveform with parameters on a calibration block of known properties.

18. A method of acoustic analysis for an electrochemical device or electrochemical material, the method comprising performing acoustic analysis on an electrochemical device or electrochemical material using the electrochemical device or electrochemical material acoustic analysis system of any preceding claim.

19. A computer readable storage medium comprising a program for a computer configured to cause a processor to perform the method of claim 18.

20. A sensor head for acoustic analysis of an electrochemical device or electrochemical material, the sensor head comprising:an electromagnetic acoustic transducer configured for contactless acoustic measurements;a piezoelectric transducer configured for contact acoustic measurements; andat least one auxiliary sensor.

21. The sensor head of claim 20, wherein the at least one auxiliary sensor is a distance sensor configured to determine the distance between the sensor head and the electrochemical device or electrochemical material and / or maintain a constant distance between the sensor head and the electrochemical device or electrochemical material.

22. The sensor head of any of claims 20 to 21, wherein the at least one auxiliary sensor is a force sensor configured to sense an indication of force applied to the piezoelectric transducer.

23. The sensor head of any of claims 20 to 22, wherein the at least one auxiliary sensor is a temperature sensor configured to sense an indication of temperature of theelectrochemical device or electrochemical material.

24. The sensor head of any of claims 20 to 23, wherein the sensor head is configured to be detachable from a sensor mount.

25. The sensor head of any of claims 20 to 24, further comprising a pulse receiver configured to control the electromagnetic acoustic transducer and / or the piezoelectric transducer and / or the at least one auxiliary sensor.

Images