Perturbator and battery management system

Abstract

A battery management system comprising one or more batteries 20 and electric circuitry connected to the batteries and further connectable to a power source 40 for charging and / or to an electric load 3

Description

Field of the Invention The present invention relates to a perturbator, and to a battery management system comprising a 5 perturbator. Background To improve battery performance and longevity, various controls and diagnostics are typically performed during battery charge / discharge. 10 For example, battery management systems (BMS) can employ dynamic controls to improve system performance. While conventional BMS employ a mixture of constant electrical current (I), constant voltage (V) or constant power (P) regimens to charge / discharge the cells / battery, it has been found that dynamic charging whereby the l / V / P is not kept constant, can provide a more efficient operation. For example, pulse charging has been found to improve charging efficiency and to extend the cycle life of batteries. 15 Specifically, pulse charging can inhibit the growth of lithium dendrites and facilitate a stable solid LO electrolyte (SEI) film, thereby inhibiting battery degradation. Additionally, pulse charging can improve CM battery performance in in low-temperature environments by effectively preheating the battery. CO Other types of beneficial dynamic controls include for example variable resistance control where the C—electric current can be decreased in response to spikes in resistance in order to reduce a risk of battery CM^O damage. This can be particularly advantageous in the context of pulse charging. 1— Additionally, it is desirable to be able to obtain measurements, such as impedance measurements, during battery charge / discharge to measure performance and lifetime metrics including state of health, state of charge, and internal resistance of the batteries. However, performing battery diagnostics as well as dynamic controls and / or dynamic 25 charging / discharging typically requires a hardware upgrade in the BMS, which makes it costly to implement. Additionally, it can also require a high degree of optimisation and predictive control, further increasing complexity and costs. The present invention has been devised in light of the above considerations. 30 Summary of the Invention In a first aspect, there is provided a battery management system according to claim 1. The perturbator may be configured to perturb the electromagnetic energy within the circuitry, such as within a portion of the circuitry. The electromagnetic energy may include inductive energy, capacitive energy, magnetic potential energy, and / or electric potential energy. Perturbing the electromagnetic energy through the electric circuitry may include: halting the flow of current through the circuitry, e.g. temporarily, and / or perturbing the voltage (electric potential) within the circuitry, e.g. without current flow, and / or altering a magnitude and / or direction and / or rate of electric current through the circuitry. Halting the flow of current through the circuitry may include restricting (e.g. 5 temporarily restricting) the flow of current through the circuitry. This may be achieved by perturbing the Lorentz force such that it interacts with the electrons in the circuitry in a way that redirects them (i.e. changes their direction). Thus, the flow of electric current can be reduced temporarily or even stopped temporarily. Typically, after a temporary reduction in electric current flow, there will likely be a surge of electric current flow in the opposite direction i.e. in the original current flow direction. 10 Therefore, the perturbator of the present disclosure is configured to control the ripple effect within the circuitry (i.e. by perturbing the electromagnetic energy within the circuitry in a predictable manner) so as to create a benefit in the electrochemistry of the one or more batteries. For example, controlling the ripple effect in the circuitry can allow a more even deposition of lithium ions within the one or more batteries. Thus, the electromagnetic energy within the circuitry and therefore electric and magnetic properties of the 15 circuitry can be altered as desired using the perturbator, without needing to upgrade the circuitry hardware. LO CXI In some examples, the perturbator may be used to disrupt a constant current rate and / or direction through the circuitry to alter a constant charging pattern to a pulse charging pattern. CO In some examples, the perturbator may be used to disrupt a constant current rate and / or direction to facilitate obtaining measurements on the electric circuitry / battery(s) during operation. CXJ In some examples, the perturbator may be configured to generate known magnetic wave functions. 1 Then, the response in one or more of the cell / battery properties can be measured. The measurements may include current measurements and / or voltage measurements and / or impedance measurements, and / or amplitude measurements, and phase shift measurements, and capacitance measurements, and 25 inductance measurements. The differences between the input and the output wave functions (e.g. phase shift and amplitude) can be assessed for various frequencies to determine the capacitance, inductance and resistance of the system. These may be used to help determine battery performance and battery lifetime metrics including state of health, state of charge, and / or internal resistance during operation, i.e. not in a separate testing cycle which halts operation. Thus, the perturbator may be used for reliable and 30 non-invasive battery diagnostics which does not require interrupting operation of the system. The measurements may be performed by the perturbator or by a measurement unit. The battery management system may comprise the measurement unit. In some examples, the perturbator may be used to perform a variable resistance control on the circuitry. The resistance is typically not constant during the charge / discharge of a cell / battery and can rise to a 35 maximum during certain operation. It may be beneficial, during stages of both low and high resistance to perturb the system to vary the resistance beyond what would normally occur. Benefits may include redistribution of localised resistance build-up e.g. clustering of lithium ions. The perturbator may be reversibly couplable to the electric circuitry. In this way, the perturbator may be retrofittable to any existing circuitry as a reversibly couplable add-on component. The perturbator may be coupled to the electric circuitry at any location of the electric circuitry. In some examples, the perturbator may be coupled to a location on the electric circuitry distal the one or more 5 batteries, for example a location which is closer to the power source or the electrical load than to the one or more batteries on the electric circuitry. This can help obtain decoupled measurements of different parameters, such as more accurate impedance measurements. As mentioned above, the perturbator can perturb the electromagnetic energy within the circuitry by generating a changing magnetic field. The changing magnetic field may be a time-varying magnetic field 10 whose magnitude and / or direction and / or distribution and / or frequency varies over time. In some examples, the changing magnetic field may be quasi-variable overtime. That is, the changing magnetic field may be periodically switched on and off overtime such that it has a periodically alternating zero and non-zero magnetic field profile. The changing magnetic field may be rotating and / or pulsed and / or oscillating. 15 The changing magnetic field may have a frequency of at least 0.001 Hz, or at least 0.01 Hz, or at least 0.1 Hz, or at least 1 Hz, or at least 10 Hz, or at least 20 Hz, or at least 50 Hz, or at least 75 Hz, or at least 90 Hz. The changing magnetic field may have a frequency of 100 kHz or less, or 90 Hz or less, or 75 Hz or less, or 50 Hz or less, or 25 Hz or less, or 10 Hz or less, or 1 Hz or less, or 0.1 Hz or less, or 0.01 Hz or less. The changing magnetic field may have a magnitude of at least 0.01 mT, or at least 0.1 mT, or at 20 least 1 mT, or at least 10 mT, or at least 100 mT, or at least 250 mT, or at least 500 mT, or at least 750 mT, or at least 1 T, or at least 2 T, or at least 5 T, or at least 7 T, or at least 10 T. The changing magnetic field may have a magnitude of 10 T or less, 7 T or less, 5 T or less, 2 T or less, 1 T or less, 750 mT or less, 500 mT or less, 250 mT or less, 100 mT or less, 10 mT or less, 1 mT or less, 0.1 mT or less. The electric circuitry may comprise one or more cables. For example, the electric circuitry may comprise 25 one or more positive battery cables for connection to positive terminal(s) of the one or more batteries in the battery management system. The electric circuitry may comprise one or more negative cables for connection to negative terminal(s) of the one or more batteries in the battery management system. The one or more batteries may be Li-ion batteries, or electrolysers, or any other electrochemical system, including but not limited to battery cells using other ions e.g. sodium, and other battery formats such as 30 redox flow batteries, and fuel cells such as hydrogen, and electrolyte such as water. The one or more batteries may be quasi-solid-state and / or all-solid-state batteries. The one or more batteries may be coin battery cells, cylindrical battery cells, pouch battery cells, or prismatic battery cells. The battery management system may comprise a plurality of batteries. The plurality of batteries may be arranged and connected in one or more battery modules. The plurality of batteries may provide a battery 35 pack. The battery pack may be for powering an electric vehicle (EV), or the battery pack may be for use with a stationary battery storage system, or the battery pack may be for powering a portable electronic device such as a mobile phone. The battery management system may be for use with an EV, or a stationary battery storage system, or portable electronic devices such as mobile phones. The electrical load may be an EV system such as an electric motor, or the electrical load may be electrical equipment in a building in the example of a stationary battery storage system, or the electrical 5 load may be powering portable electronics such as mobile phones. The magnetic field generator may comprise one or more transmitter coils configured to generate the changing magnetic field. In some examples, selected one(s) of the transmitter coils may be configured to generate respective different magnetic fields (i.e. magnetic field waveforms) to the magnetic field(s) generated by at least some of the remaining transmitter coils. In some examples, each transmitter coil 10 may be configured to generate a respective changing magnetic field. In other examples, each transmitter coil may be configured to generate a static (i.e. constant) magnetic field and the magnetic field generator may be configured to produce the changing magnetic field by switching selected one(s) of the transmitter coils on and off overtime. The / each transmitter coil may comprise one or more turns (windings), such as just one turn, or a plurality 15 of turns. When the / each transmitter coil comprises a plurality of turns, the turns may be arranged in a helical configuration, i.e. overlying one another. u; The perturbator, for example the magnetic field generator, may be connectable to a power supply in order CM to obtain power for generating the changing magnetic field. The power supply may be the one or more CO batteries. That is, the one or more batteries may supply current to the perturbator (e.g. to the one or more transmitter coils) to generate the changing magnetic field. C\J In some examples, the power supply may be distinct from the one or more batteries. The power supply 1 may be distinct from the power source which is configured to charge the one or more batteries. Alternatively, the power supply may coincide with the power source which is configured to charge the one or more batteries. That is, the power source may be configured both to charge the or more batteries, and 25 to power the perturbator, e.g. the magnetic field generator of the perturbator. The power supply may be configured to supply respective different current signals (e.g. waveforms) to respective different transmitter coils. In this way, the perturbator may be tuned via waveform control to produce asymmetric or ‘biased’ perturbations. The perturbator may comprise the power supply for powering the magnetic field generator. The one or 30 more transmitter coils may be electrically connected to the power supply. The perturbator may comprise a housing enclosing the one or more transmitter coils and / or the one or more receiver coils (discussed below) and / or the power supply. The housing may be formed of a ferromagnetic material such that the housing can transmit magnetic flux generated by the perturbator to the electric circuitry. This housing may provide the additional function / benefit of acting as a field guide. 35 The housing may be elongated. The housing may be tubular. The housing may have an elongated block shape. The perturbator may comprise a controller. The controller may be configured to control the changing magnetic field generated by the perturbator (e.g. by the magnetic field generator). The controller may be configured to control the magnitude and / or direction and / or distribution and / or frequency of the changing magnetic field overtime. When the perturbator comprises a plurality of transmitter coils, the controller 5 may be configured to switch on / off selected one(s) of the plurality of the transmitter coils in a time-varying manner, e.g. to produce the changing magnetic field or to temporarily disable magnetic field generation. In some examples, the controller may be configured to sequentially activate the plurality of transmitter coils. The controller may be configured to adjust operation of the perturbator, e.g. to adjust the generated 10 changing magnetic field based on feedback from the electric circuitry. For example, the electric circuitry may comprise a feedback circuit and the controller may be coupled to the feedback circuit to receive feedback signals therefrom. Alternatively, or additionally, the controller may be coupled (e.g. electrically or communicatively coupled) to the measurement unit in order to obtain feedback data therefrom, e.g. in the form of measurements. 15 The perturbator may couple to the electric circuitry wirelessly or via a wired connection, as discussed below. LO In some examples, the perturbator may be wirelessly couplable to the electric circuitry such that the generated changing magnetic field perturbs the electromagnetic energy within the circuitry. CO That is, the perturbator may be arranged relative to the electric circuitry such that at least a portion of the circuitry is placed within the changing magnetic field generated by the perturbator. That way, the perturbator may perturb inductive energy, capacitive energy, magnetic potential energy, and / or electric potential energy within the electric circuitry. For example, when current flows through the electric circuitry during operation, a magnetic field is generated in the vicinity of and around the circuitry according to the laws of electromagnetism. The 25 perturbator may be arranged relative to the electric circuitry such that changing magnetic field generated by the magnetic field generator at least partially spatially overlaps the magnetic field produced by the current-carrying circuitry. In this way, the changing magnetic field produced by the perturbator can interfere with the magnetic field produced by the circuitry, thereby perturbing the electromagnetic energy within the circuitry, for example in one of the ways discussed above. The changing magnetic field 30 produced by the perturbator may interfere with the magnetic field produced by the circuitry constructively and / or destructively. In this way, the interference can dampen or enhance characteristics of the electric circuit. To ensure that the changing magnetic field produced by the perturbator permeates at least a portion of the electric circuitry, the perturbator may be arranged in close physical proximity to the circuitry. To this 35 end, the perturbator may be shaped and sized such that it can be placed in physical proximity to a portion of the circuitry. For example, the perturbator may be shaped and sized so as to at least partially surround a portion of the electric circuitry. In some examples, the perturbator (e.g. its housing) may comprise one or more curved portions. In some examples, the perturbator (e.g. its housing) may define an opening for receiving a cable portion 5 e.g. a portion of the electric circuitry. The cable portion may be thus threaded through the opening in the perturbator. In some examples, the perturbator may comprise one or more transmitter coils in the form of solenoids. The empty core(s) of the solenoid(s) may individually or together define the opening for receiving the cable portion. For example, the solenoids may be arranged concentrically such that their respective cores form a passage to provide the opening of the perturbator. 10 In some examples, the perturbator may comprise a pair of jaws. The pair of jaws may be movable between a closed configuration in which the jaws are in contact to define the opening, and an open configuration in which the jaws are spaced from one another to allow insertion of the portion of the circuitry (e.g. a cable portion) into the opening. In this way, the perturbator can be easily electromagnetically coupled to existing circuitry using the movable jaws to surround a portion of the 15 circuitry. The pair of jaws may be provided by the housing of the perturbator. The one or more transmitter coils may be enclosed within the pair of jaws. LO In some examples, the perturbator may comprise a plurality of transmitter coils arranged so as to sandwich at least one cable portion, such as a straight cable portion, therebetween. CO In some examples, the transmitter coils may sandwich at least one coiled cable portion comprising at least one turn (winding).. In some examples, the transmitter coil(s) may be arranged to face and / or abut at least one coiled cable portion. In some examples, the at least one coiled cable portion may be coiled around a portion of the perturbator, for example, around a portion of a transmitter coil. In some examples, the at least one coiled cable portion may be threaded through the opening of the perturbator and may be subsequently coiled around a portion of the perturbator, for example around a portion of the magnetic 25 field generator such as around a transmitter coil. In some examples, the perturbator may comprise a plurality of transmitter coils alternately arranged with a plurality of coiled cable portions, e.g. such that each coiled cable portion is sandwiched between a pair of transmitter coils. The one or more cable portions (coiled or straight) may be part of the electric circuitry, e.g. part of cables 30 of the electric circuitry. For example, the one or more cable portions may be part of a positive and / or negative battery cables of the circuitry. Alternatively, the perturbator may comprise the one or more cable portions (coiled or straight). For example, the one or more cable portions may be enclosed within the perturbator housing e.g. together with the one or more transmitter coils. The one or more cable portions may be electrically connectable to 35 the electric circuitry. The one or more cable portions may be electrically connected to one or more ports of the perturbator, as discussed in more detail below. The one or more cable portions may comprise a positive cable portion and a negative cable portion. The positive cable portion may be electrically connectable to the positive battery cable of the electric circuitry. The negative cable portion may be electrically connectable to the negative battery cable of the electric circuitry. In some examples, the perturbator may be electrically connectable to the electric circuitry via a wired connection. The perturbator may be electrically connectable to and in line with the electric circuitry. As 5 mentioned above, the perturbator may comprise one or more, such as two, ports for connection to the electric circuitry. Specifically, one or more portions of the electric circuitry (such as cables) may be configured to be plugged into the one or more ports of the perturbator to provide the wired connection therebetween. The one or more ports may be provided in the housing of the perturbator. In some examples, the perturbator may comprise a first port and a second port. The first port may 10 comprise a positive terminal of the perturbator, and the second port may comprise a negative terminal of the perturbator. The perturbator may be configured to supply electric current into the electric circuitry via the wired connection so as to perturb the electromagnetic energy within the circuitry. 15 CXI '20 CXI When the perturbator comprises the one or more cable portions (straight or coiled), the one or more cable portions may be placed in close physical proximity to the transmitter coil(s) of the perturbator such that the changing magnetic field generated by the transmitter coil(s) permeates the cable portion(s) to perturb electromagnetic energy therein. In this way, electromagnetic energy within the wider circuitry can be perturbed when the perturbator (and therefore the cable portion(s)) is electrically connected to the circuitry (e.g. via the ports). The magnetic field generator may comprise one or more receiver coils in addition to the one or more transmitter coils. The / each receiver coil may have one or more turns (windings). The one or more receiver coils may be configured to receive the magnetic field(s) generated by the one or more transmitter coils. In this way, an electric current can be induced in the one or more receiver coils. The one or more receiver coils may be electrically connectable to the circuitry, e.g. via the one or more 25 ports of the perturbator. In this way, the induced current(s) may be injected into the electric circuitry via the wired connection to perturb the electromagnetic energy within the circuitry. In some examples, the one or more receiver coils may be electrically connected to a positive battery cable, or a negative battery cable of the electric circuitry. The one or more receiver coils may be electrically connected to the one or more cable portions of the perturbator. For example, the one or more 30 receiver coils may be electrically connected to a positive cable portion, or to a negative cable portion. In some examples, the one or more transmitter coils may be electrically connected in parallel to the one or more receiver coils. Alternatively, the one or more transmitter coils and the one or more receiver coils may be electrically connected to respective different circuits (e.g. within the perturbator). In some examples, the one or more receiver coils may be oriented parallel to the one or more transmitter 35 coils. In other examples, the one or more receiver coils may be oriented orthogonal to the one or more transmitter coils. In some examples, the one or more receiver coils may be interwound with the one or more transmitter coils in single coil. The wires of the receiver and the transmitter coils may be covered with an electrically insulating material, such as enamel, such that the wires of the receiver coils and transmitter coils can touch without conducting electricity from one another. In this way, the transmitter and receiver coils can 5 be closely wound together in a single, compact coil. The battery management system may be characterized by a charge current lc, which may be the minimum amount of current required to effectively charge the one or more batteries. The electric current supplied by the perturbator may have a smaller magnitude than that of the charge current lc- In other words, the perturbator may be configured to supply a current to the electric circuitry which, on its own, is 10 insufficient to charge the one or more batteries within a short timeframe. For example, the electric current supplied by the perturbator may have a magnitude that is less than 50%, or less than 30%, or less than 20%, or less than 10%, or less than 5% or less than 1% of the charge current lc- In some examples, the battery management system may comprise a wireless charger configured to charge the one or more batteries. The wireless charger may comprise a charger transmitter coil 15 configured to produce magnetic flux to charge the one or more batteries. The electric circuitry may comprise a charger receiver coil configured to receive the magnetic flux from the wireless charger in order _ to supply electric current to the one or more batteries for charging. LO The perturbator may be provided in addition to, and separately to the wireless charger such that the wireless charger and the perturbator are functionally distinct. The purpose of the wireless charger may be ^^^20 to charge the one or more batteries, while the purpose of the perturbator may be to perturb the _ electromagnetic energy within the electric circuit so as to adjust its characteristics as desired. CM Alternatively, the wireless charger may comprise the perturbator. In this case, the wireless charger may be configured to transmit a superposition of two changing magnetic fields (waveforms) - one for charging and one for perturbation. For example, the charger transmitter coil may be configured to generate a 25 charging magnetic field and the magnetic field generator of the perturbator may be configured to generate a perturbing (changing) magnetic field. In other examples, the charger transmitter coil may be configured to generate both the charging magnetic field and the perturbing magnetic field. This may be achieved by driving the charger transmitter coil using an arbitrary waveform as input. The charging magnetic field may have a higher frequency than the perturbing magnetic field. For example, the perturbing magnetic field 30 may have a frequency that is less than 50%, or less than 30%, or less than 20%, or less than 10%, or less than 5%, or less than 1%, or less than 0.1%, or less than 0.01% of the frequency of the charging magnetic field. Additionally, or alternatively, the frequency of the perturbing magnetic field may be at least 0.005%, or at least 0.01%, or at least 0.1%, or at least 1%, or at least 5%, or at least 10%, or at least 20%, or at least 30% or at least 50% of the frequency of the charging magnetic field. In some examples, 35 the charging frequency may be suitable for high-power EV charging. For example, the charging frequency may be around 130kHz. In some examples, the perturbing magnetic field may have a frequency of between 13 Hz (i.e. 0.01% of 130 kHz) and 130 Hz (i.e. 0.1% 130 kHz) inclusive. The superimposed magnetic fields may be transmitted to a receiver coil of the battery management system such as a charger receiver coil. The perturbator may comprise a magnetic field guide. The magnetic field guide may be formed of a ferromagnetic material. The magnetic field guide may be configured to transmit magnetic flux generated by the perturbator to the electric circuitry, to improve coupling between the perturbator and electric circuitry. The one or more transmitter coils may be mounted to the magnetic field guide such that the generated magnetic field(s) are transmitted to the magnetic field guide. The magnetic field guide may then guide the generated field(s) to the electric circuitry so as to perturb electromagnetic energy therein. In some examples, the one or more transmitter coils may be mounted to the magnetic field guide. The one or more transmitter coils may be wound around portion(s) of the magnetic field guide. In some examples, two or more transmitter coils may be mounted to the magnetic field guide. The magnetic fields generated by the two or more transmitter coils may interfere to provide a superimposed magnetic field waveform which is the changing magnetic field produced by the magnetic field generator of the perturbator. In some examples, the one or more transmitter coils and the one or more receiver coils may be mounted to (e.g. coiled around) the magnetic field guide. In this way, the magnetic field guide may improve transmission of magnetic flux from the transmitter coil(s) to the receiver coil(s). The relative location of the transmitter coil(s) and the receiver coil(s) on the magnetic field guide may be selected to tune waveform characteristics in the receiver coil(s). The magnetic field guide may be used passively (i.e. when one or more transmitter coils are switched off) to filter current spikes during charge / discharge. The magnetic field guide may comprise a frame. The frame may comprise one or more limbs. The transmitter coil(s) and / or the receiver coil(s) may be mounted to (e.g. coiled around) limbs of the frame. In some examples, the frame may comprise a pair of opposing limbs. The receiver coil(s) may be mounted to (e.g. coiled around) one of the opposing limbs, and the transmitter coil(s) may be mounted to (e.g. coiled around) the other of the opposing limbs). In some examples, the perturbator may comprise two or more transmitter coils, mounted to (e.g. coiled around) respective opposing limbs of the magnetic field guide. The frame may be stadium-shaped defining a stadium-shaped inner opening. The pair of opposing limbs may be the pair of long sides of the stadium-shaped frame. The transmitter coil(s) and / or the receiver coil(s) and / or the cable portion(s) and / or the magnetic field guide may be enclosed within the housing of the perturbator. In a second aspect, there is provided an electric vehicle (EV) charge point comprising the battery management system of the first aspect. The electric circuitry may include a charging cable of the EV charge point. The charging cable may be connected to the grid (i.e. power source) and may be connectable to an EV battery pack which includes one or more batteries. The perturbator may be configured to perturb electromagnetic energy within the circuitry, e.g. within the charging cable. In some examples, the perturbator may be coupled to the charging cable wirelessly, as described above. For example, the perturbator may be arranged so as to at least partially surround a portion of the charging cable. When the perturbator comprises a pair of jaws, the perturbator may be clamped around a portion of the charging cable. 5 In some examples, the perturbator may be electrically connectable to the charging cable (electric circuitry) via a wired connection, as described above. For example, the charging cable may be plugged into one of the first and second ports of the perturbator. The perturbator may be electrically connected to the EV charge point (and therefore to the power source, e.g. the grid), for example via the other one of the first and second ports of the perturbator. In some examples, the power cable of the perturbator may 10 electrically connect the EV charge point to a port of the perturbator. In this way, the perturbator can be interposed between the charge point and the EV. In some examples, the perturbator may be configured to draw power from the charge point (e.g. from the grid) via an electric connection to the charge point (e.g. via a power cable). In a third aspect, there is provided a charger for charging a portable electronic device, the charger 15 comprising the battery management system of the first aspect. The portable electronic device may be for example a mobile phone. The charger may comprise a LO charging cable which is part of the electric circuitry. The charging cable may be connectable to the battery CM of the portable electronic device, and further connectable to the power source (which may be the grid). CO The charger may comprise an electric plug for insertion into an electric socket to connect to the power source. The electric plug may comprise the perturbator. The perturbator may be connected to the charging cable (circuitry) via a wired connection, for example in one of the ways described above. The perturbator may be electrically connectable to the power source to draw power therefrom (e.g. via the pins of the electric plug). In a fourth aspect, there is provided a perturbator for use with the battery management system of the first 25 aspect, the perturbator comprising: a magnetic field generator configured to generate a changing magnetic field; wherein the perturbator is couplable to electric circuitry to perturb electromagnetic energy within the circuitry using the changing magnetic field. The perturbator have any one or any combination of the features of the perturbator described with 30 reference to the battery management system of the first aspect, except where such a combination is clearly impermissible or expressly avoided. For examples, the perturbator may be wirelessly couplable to an electrical circuitry. Alternatively, the perturbator may be couplable to an electrical circuitry via a wired connection. The perturbator may be mountable to and electrically connectable to an EV charge point. The EV charge 35 point may have electric circuitry including a charge cable. The charge cable may be connected to the grid and may be connectable to an EV battery pack. The perturbator may be configured to perturb electromagnetic energy within the circuitry, e.g. within the charge cable. To this end, the perturbator may be arranged so as to at least partially surround a portion of the charge cable. For example, when the perturbator comprises a pair of jaws, the perturbator may be clamped around a portion of the charge cable. The perturbator may be configured to draw power from the charge point (e.g. from the grid) via its electric connection to the charge point (e.g. via a power cable). 5 Ina fifth aspect, there is provided a method of perturbing electromagnetic energy within electric circuitry using a perturbator, according to claim 24. The perturbator may have any one or any combination of the features of the perturbator of the fourth aspect. In a sixth aspect, there is provided a method of perturbing electromagnetic energy within electric circuitry 10 in a battery management system, wherein: the battery management system comprises: one or more batteries; electric circuitry electrically connected to the one or more batteries, and further connectable to a power source for charging and / or to an electrical load for discharging; and 15 a perturbator comprising a magnetic field generator configured to generate a changing magnetic field, the perturbator being couplable to the electric circuitry to perturb electromagnetic energy within the circuitry using the generated changing magnetic field, the method comprising: coupling the perturbator to the electric circuitry; generating the changing magnetic field to perturb the electromagnetic energy within electric circuitry. The battery management system may have any one or any combination of the features of the battery management system of the first aspect. As discussed above, coupling the perturbator to the electric circuitry may be wireless, i.e. by arranging 25 the perturbator such that the generated changing magnetic field interferes with the magnetic field produced by the current-carrying electric circuitry during operation. Alternatively, coupling the perturbator to the electric circuitry may involve electrically connecting the perturbator to the electric circuitry via a wired connection. The invention includes the combination of the aspects and preferred features described except where 30 such a combination is clearly impermissible or expressly avoided. Summary of the Figures Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: 35 Figure 1 schematically shows a variant of a battery management system according to the present disclosure. Figure 2 schematically shows a variant of a battery management system according to the present disclosure. Figures 3A and 3B schematically show an example implementation of a perturbator according to the present disclosure, respectively in a closed configuration and in an open configuration. 5 Figures 4A and 4B show the perturbator of Figures 3A and 3B being used with an EV charge point. Figure 5 shows an implementation of a battery management system according to the present disclosure in which the battery management system comprises a wireless charger which includes the perturbator. Figure 6A shows a magnetic field waveform produced by the wireless charger; Figure 6B shows a magnetic field waveform produced by the perturbator; Figure 6C shows a superposition of the waveforms 10 of Figures 6A and 6B. Figures 7A and 7B schematically show an implementation of a perturbator according to the present disclosure respective connected to electric circuitry and disconnected from the electric circuitry. Figure 8 schematically shows an example implementation of battery management system comprising the perturbator according to Figures 7A-7B. 15 Figure 9 schematically shows an example implementation of a battery management system comprising LO the perturbator according to Figures 7A-7B. CM Figures 10A, 10B, 10C, 10D and 10E respectively show example implementations of the current perturbator of Figure 7A-7B. _ Figures 11A and 11B show an example implementation of the perturbator of Figures 7A-7B for use in EV CM 20 charging. 1— Figures 12A and 12B show an example implementation of the perturbator of Figures 7A-7B for use in portable electronics charging. Figure 13A and 13B schematically show example implementations of a perturbator according to the present disclosure. 25 Figure 14A and 14B schematically show example implementations of a perturbator according to the present disclosure. Figure 15A, 15B, 15C, and 15D schematically show example implementations of a perturbator according to the present disclosure. Figure 16A and 16B schematically show example implementations of a perturbator according to the 30 present disclosure. Figure 17A and 17B schematically show example implementations of a perturbator according to the present disclosure. Figure 18 schematically shows an example implementation of a perturbator according to the present disclosure. Figure 19 schematically shows an example implementation of a perturbator according to the present disclosure. Figure 20A, 20B, 20C, and 20D respectively show a perspective view, a front view, a side view, and a top view of a perturbator according to the present disclosure. 5 Figure 21 A, 21B, and 21C show respective battery management systems comprising a perturbator of the type of Figures 20A-20D. Detailed Description of the Invention Aspects and embodiments of the present invention will now be discussed with reference to the 10 accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference. The present disclosure provides a battery management system 100. An example implementation of the battery management system 100 is shown in Figure 1. 15 CXI CXI20 The battery management system (BMS) 100 comprises a battery 20 and electric circuitry 50 electrically connecting the battery 20 to a power source 40 for charging and to an electrical load 30 for discharging. The BMS 100 also comprises a perturbator 60. The perturbator 60 comprises a magnetic field generator 67 configured to generate a changing magnetic field. The perturbator 60 is couplable to the electric circuitry 50 to perturb electromagnetic energy within the circuitry 50. In the example of Figure 1, the circuitry 50 is for wired charging of the battery 20 as it electrically connects the battery 20 to the power source 40 in a wired manner. The circuitry 50 comprises a positive battery cable 52 and a negative battery cable 54 for connection to the positive and negative battery terminals respectively. The battery 20 in this example is a Li-ion battery, such as a cylindrical Li-ion battery. It is envisaged that the battery 20 may be a plurality of batteries, for example arranged in one or more battery modules and / or providing a battery pack such as battery pack for an EV. 25 The perturbator 60 in Figure 1 is wirelessly, reversibly couplable to the electric circuitry 50 such that the generated changing magnetic field perturbs the electromagnetic energy within the circuitry 50. Specifically, in operation, at least a portion of the electric circuitry 50 is placed within the generated changing magnetic field such that the changing magnetic field permeates the portion of the circuitry 50 and its vicinity to perturb electromagnetic energy within the circuitry, such as inductive energy, capacitive 30 energy, magnetic potential energy, and / or electric potential energy. When current flows through the electric circuitry 50, the changing magnetic field generated by the perturbator 60 interferes with the magnetic field produced by the current-carrying electric circuitry 50. This causes the current flow through the circuitry 50 to be perturbed. To decouple the perturbator 60 from the electric circuitry 50, it suffices that the changing magnetic field is prevented from permeating the electric 35 circuitry (or from interfering with the magnetic field produced by the electric circuitry 50), e.g. by switching off the changing magnetic field of the electromagnetic energy within the circuitry 50, or by spacing the perturbator 60 and the circuitry 50. The changing magnetic field is time-varying such that its magnitude and / or direction and / or distribution and / or frequency vary overtime. In this example, the changing magnetic field has a frequency between 0.001 Hz and 100 kHz, and a magnitude between 0.01 mT and 10 T. The magnetic field generator 67 in this example comprises a transmitter coil 64 configured to generate 5 the changing magnetic field. The transmitter coil 64 is connected to a power supply 80. In this example, the power supply 80 is distinct from the power source 40 for charging the battery, and is comprised by the perturbator 60. However, it is envisaged that the two may be the same, or the perturbator 60 may be powered by the battery 20 itself instead. Although not shown in the figures, the BMS 100 may comprise a measurement unit configured to obtain 10 measurements on the electric circuitry / battery(s) during operation. In some examples, the perturbator 60 generates known magnetic wavefunctions, and the measurement unit measures the response in the battery 20. The measurements obtained in this way may include impedance measurements, and / or amplitude measurements, and phase shift measurements. The perturbator 60 can also comprise a controller. The controller is not shown in the Figures but may be provided in the same housing as the 15 transmitter coil 64, and communicatively (e.g. electrically) coupled thereto. The controller may be configured to control the changing magnetic field generated by the perturbator 60 (e.g. by the magnetic field generator 67). The controller may be configured to adjust the generated changing magnetic field based on feedback from the electric circuitry 50. For example, the electric circuitry 50 may comprise a feedback circuit and the controller may be coupled to the feedback circuit to receive feedback signals 20 therefrom. Alternatively, or additionally, the controller may be coupled to the measurement unit in order to obtain feedback data from therefrom, in the form of measurements. Figure 2 shows a different implementation of the BMS 100. The BMS 100 of Figure 2 differs from the BMS 100 of Figure 1 in that the electric circuitry 50 is for wireless charging of the battery 20. In this case, the BMS 100 comprises a wireless charger 57 which includes the power source 40. The wireless charger 25 57 also includes a charger transmitter coil 58 electrically coupled to the power source 40 to generate magnetic flux for wireless charging. The circuitry 50 includes a charger receiver coil 59 wirelessly coupled to the charger transmitter coil 58 so as to receive the generated magnetic flux. The wireless charger 57 is configured to induce a charge current lc in the circuitry 50 to charge the battery. The electric current supplied by the perturbator 60 has a smaller magnitude than that of the charge current lc- In other words, 30 the perturbator 60 is configured to supply a current to the electric circuitry 50 which, on its own, is insufficient to charge the battery 20. For example, the electric current supplied by the perturbator 60 has a magnitude that is less than 50%, or less than 30%, or less than 20%, or less than 10%, or less than 5% or less than 1% of the charge current lc- Figures 3A and 3B show an implementation of a perturbator 60 according to the present disclosure. 35 The perturbator 60 defines an opening 75 for receiving a portion of the electric circuitry 50, such as a portion of a cable of the electric circuitry 50. The perturbator 60 comprises a pair of jaws 76, 78. The jaws 76, 78 are movable between a closed configuration (shown in Figure 3A), in which the jaws 76, 78 are in contact to define the opening 75, and an open configuration (shown in Figure 3B) in which the jaws 76, 78 are spaced from one another to allow insertion of the portion of the circuitry 50 into the opening 75. The pair of jaws 76, 78 is provided by the housing 68 of the perturbator 60. The transmitter coil 64 is enclosed within the pair of jaws 76, 78. It is envisaged that a plurality of transmitter coils 64 may be enclosed within the pair of jaws 76, 78. The 5 perturbator 60 comprises a power cable 79 for connection to the power supply 80 which in this case is not housed within the jaws 76, 78. The perturbator 60 of Figures 3A and 3B can be used to perturb electric circuitry 50 for EV charging. This is shown in Figures 4A and 4B, where the perturbator 60 is mounted to and electrically connected to an EV charge point 97 via the perturbator’s power cable 79. The EV charge point 97 has a charging cable 98 10 which is connectable to an EV to electrically connect the EV battery pack 20 to the grid (i.e. power source 40). The perturbator 60 is clamped around the charging cable 98 using its movable jaws 76, 78. In this way, the perturbator 60 wirelessly couples to the charging cable 98 to perturb electromagnetic energy within the charging cable 98. The perturbator 60 is powered by the EV charge point 97 via the perturbator’s power cable 79. 15 Next, Figure 5 shows another implementation of a battery management system 100 according to the present disclosure. The BMS 100 comprises a wireless charger 57 as discussed with reference to Figure LO 2. However, in this implementation, the wireless charger 57 comprises the perturbator 60, in addition to the charger transmitter coil 68. The wireless charger 57 is electrically coupled to an EV charge point 97, and therefore to the power source 40 (e.g. the grid), via a cable 105. t~^?0 The wireless charger 57 is configured to transmit a superposition of two changing magnetic fields (waveforms) - one for charging and one for perturbation. The charging transmitter coil 58 is configured to transmit a changing magnetic field for charging (i.e. a charging magnetic field), while the one or more transmitter coils 64 of the perturbator 60 are configured to transmit a different changing magnetic field (i.e. perturbing magnetic field) to perturb electromagnetic energy through circuitry 50 on-board of the EV 25 99. The charging magnetic field, which is shown in Figure 6A, has a higher frequency than the perturbing magnetic field, which is shown in Figure 6B. The perturbing magnetic field has a frequency that is less than 50%, or less than 30%, or less than 20%, or less than 10%, or less than 5% or less than 1% of the frequency of the charging magnetic field. The charging magnetic field and the perturbing magnetic field 30 are superimposed into a single waveform, as shown in Figure 6C, which is transmitted to the charger receiver coil 59 on-board of the EV 99. As an alternative to wireless coupling, the perturbator 60 may be electrically connectable to the electric circuitry 50 via a wired connection 82, in line with the electric circuitry 50. In the example of Figures 7A and 7B, the perturbator 60 has an elongated block-shaped housing 68. The 35 perturbator 60 comprises a first port 72 and a second port 74 for connection to the electric circuitry 50. The ports 72, 74 are provided in the housing 68. The first port 72 comprises a positive terminal of the perturbator 60, while the second port 74 comprises a negative terminal of the perturbator 60. Portions of the circuitry 50 are connectable to the first 72 and second 74 ports as shown in Figures 7A and 7B. In this implementation, the perturbator 60 is a retrofittable component, which can be electrically connected to the electric circuitry 50 to perturb the electromagnetic energy therein. Figure 8 shows and implementation of the BMS 100, comprising the perturbator 60 of Figures 7A-7B. Figure 8 has electric circuitry 50, battery 20, power source 40, and load 30 identical to those described 5 with reference to Figure 1. The only difference compared to the implementation in Figure 1 is that the perturbator 60 is connected to the circuitry 50 via a wired connection 82, through its ports 72, 74. As can be seen from Figure 12, the circuitry 50 is electrically connected to each of the positive and negative terminals of the perturbator 60 (via its ports 72, 74). Figure 9 shows an alternative implementation of the BMS 100 comprising the perturbator 60 of Figures 10 7A-7B. Figure 9 has electric circuitry 50, battery 20, power source 40, load 30, wireless charger 57 and charger receiver coil 59 identical to those described with reference to Figure 2. The only difference compared to the implementation in Figure 2 is that the perturbator 60 is connected to the circuitry 50 via a wired connection 82, through its ports 72, 74. As can be seen from Figure 9, the circuitry 50 is electrically connected to each of the positive and negative terminals of the perturbator 60 (via its ports 72, 74). 15 CM 20 CXI 25 30 35 40 Next, various example implementations of the perturbator 60 of Figures 7A-7B are discussed with reference to Figures 10A-10D. With reference to Figure 10A, the perturbator 60 comprises a transmitter coil 64 and a power supply 80, in addition to the housing 68 and the ports 72, 74. The transmitter coil 64 is electrically connected to the power supply 80. The perturbator also comprises positive and negative cable portions 65 electrically connected to the positive and negative terminals of the perturbator 60. The positive and negative cable portions 65 are connectable the electric circuitry 50 (e.g. to positive battery cable and negative battery cable thereof) via the two ports 72, 74. The cable portions 65 are closely arranged to the transmitter coil 80. Thus, the transmitter coil can perturb electromagnetic energy within the cable portions, and therefore within the electric circuitry 50 when the cable portions 65 are connected to the electric circuitry 50. The perturbator 60 may not enclose its power supply 80. This is shown in Figure 10B, where the transmitter coil 64 is electrically connected to the second port 74 of the perturbator 60 (which is for connection to the power source 40) such that upon connection to the electric circuitry 50, the transmitter coil 64 can be powered by the power source 40. In the example implementations of Figures 10C-10E, the perturbator 60 also comprises a receiver coil 66 coupled to the transmitter coil 64 to receive magnetic flux (changing magnetic field) generated by the transmitter coil 64. The receiver coil 66 is electrically connected to the positive and negative terminals of the perturbator 60 (i.e. to the first 72 and second 74 ports). Thus, when the electric circuitry 50 is connected to the ports of the perturbator 60, the receiver coil 66 can supply current to (i.e. inject current into) the electric circuitry 50 so as to perturb the electromagnetic energy therein. In the example of Figure 10C, the perturbator comprises a power supply 80 which is connected to the transmitter coil 64. The receiver coil 66 is coupled to the first and second ports 72, 74 via a separate circuit. In this example, the receiver coil is electrically connected to the positive cable portion of the perturbator 60. However, it is also envisaged that the receiver coil 66 may be connected to the negative cable portion instead. In the example of Figure 10D, the perturbator 60 does not enclose a power supply 80. Instead, the transmitter coil 64 is electrically connected to the second port 74 which is for connection to the power source 40. The transmitter coil 64 and the receiver coil 66 are electrically connected to the second port 74 via separate circuits. The receiver coil 66 is connected to the positive cable portion 65, however, it is also envisaged that the receiver coil 66 may be connected to the negative cable portion instead. Finally, in the example of Figure 10E, the transmitter coil 64 and the receiver coil 66 are connected in 5 parallel, in the same circuit which is electrically connected to the first and second ports 72, 74 of the perturbator 60. The receiver coil 66 is connected to the positive cable portion 65, however, it is also envisaged that the receiver coil 66 may be connected to the negative cable portion instead. The perturbator 60 implemented in any of the ways shown in Figures 10A-10D, can be used to perturb electric circuitry 50 for EV charging. This is shown in Figures 11A and 11B. The perturbator 60 is 10 electrically connected to a charge point 97 and further electrically connected to a charging cable 98 of the EV charge point 97. The charging cable 98 is connectable to an EV 99 to electrically connect the EV battery pack 20 to the grid (i.e. power source 40). In this example, the perturbator 60 is electrically connected to the charge point 97 via its power cable 79 (which is electrically connected to the second port 74 of the perturbator 60). The charging cable 98 is plugged into the first port 72 of the perturbator 60 to 15 connect the perturbator 60 to the EV battery pack 20. In this way, the perturbator is interposed between the charge point 97 (and thus the power source 40) and the EV battery 20. In this way, the perturbator 60 can perturb electromagnetic energy within the charging cable 98. LO The perturbator 60 is also configured to draw power from the charge point 97 (e.g. from the grid) via its power cable 79. CO20 In the example of Figure 12A, the perturbator 60 implemented in any of the ways shown in Figures 10A-O 10D, is used to perturb electromagnetic energy within electric circuitry 50 portable electronics charging. Specifically, Figure 12A shows a charger 103 for charging a portable electronic device 101 (e.g. a mobile "j— phone). The charger 103 comprises a charging cable 98 (which is part of the electric circuitry 50 of the BMS 100). The charging cable 98 is connectable to the battery 20 of the portable electronic device 101, 25 and further connectable to the power source 40 (which may be the grid). The charger 103 comprises an electric plug for insertion into an electric socket to connect to the power source. The electric plug 104 which comprises the perturbator 60. The perturbator 60 is connected to the charging cable 98 via a wired connection. The perturbator is electrically connectable to the power source 40 to draw power therefrom (e.g. via the pins of the electric plug 104). The perturbator can be implemented as shown in Figure 12B 30 (which is identical to Figure 10D). Alternatively, the perturbator 60 may be implemented in any of the ways shown in Figures 10A-10C or 10E. Figures 4A and 4B show another implementation of a perturbator 60 according to the present disclosure. Similar to Figures 3A and 3B, the perturbator 60 defines an opening 75 and a cable portion is threaded through the opening 75. The cable portion is a portion of the circuitry 50, and more specifically, a portion 35 of a battery cable 52, 54, The perturbator 60 of Figure 3A comprises a transmitter coil 64 whose core defines the opening 75. The perturbator 60 of Figure 3B comprises a pair of concentric transmitter coils 64 in abutment with each other. The cores of the transmitter coils 64 define a passage which provides the opening 75 through which the cable portion is threaded. It is envisaged that the configurations of Figures 13A and 13B may be enclosed inside the housing of the perturbator 60, and the perturbator may comprise the cable portion (e,g, as per Figures 10A-1 OB where the perturbator 60 comprises cable portions 65). Thus, the cable portion and the transmitter coil(s) may be both enclosed within the perturbator housing, and the cable portion may be threaded through the 5 transmitter coil(s) as shown in Figures 13A and 13B. Similarly to the implementation of Figure 4A, the perturbator 60 of Figures 5A and 5B comprises a single transmitter coil 64. A cable portion of the circuitry 50 is threaded through the opening 75 defined by the transmitter coil 64. Additionally, the cable portion 50 is then wound around the transmitter coil 64 such that the cable portion 50 is a coiled cable portion 56. In Figure 5A, the coiled cable portion 56 comprises 1 10 turn (winding), while in Figure 5B, the coiled cable portion 56 comprises 3 turns. It is envisaged that the configurations of Figures 14A and 14B may be enclosed inside the housing of the perturbator 60, and the perturbator may comprise the cable portion (e,g, as per Figures 10A-10B where the perturbator 60 comprises cable portions 65). Thus, the perturbator may comprise a cable portion 65 which is threaded through the opening 75 of the transmitter coil 64 and subsequently wound around it as 15 shown in Figures 14A and 14B. Figures 6A to 6D show implementations of the perturbator 60 where the perturbator 60 sandwiches a cable portion of the electric circuitry 50. The perturbator 60 in these examples comprises a pair of transmitter coils 64 spaced from one another, and overlying each other. In Figure 6A, the transmitter coils LO 64 sandwich a straight cable portion of the electric circuit 50. In Figures 6B-6D the transmitter coils 64 20 sandwich a coiled cable portion 56. Specifically, in Figure 6B, the transmitter coils 64 sandwich a coiled cable portion 56 having just one turn, while in Figures 6C and 6D the transmitter coils 64 sandwich a coiled cable portion 56 having a plurality of turns (around 5). It is envisaged that the configurations of Figures 15A-15D may be enclosed inside the housing of the C\J perturbator 60, and the perturbator may comprise the cable portions which are sandwiched by the 1 25 transmitter coils 64 (e,g, as per Figures 10A-10B where the perturbator 60 comprises cable portions 65). Thus, the transmitter coils 64 may sandwich a straight cable portion 65 (as per Figure 15A), or the transmitter coils 64 may sandwich a coiled cable portion 65 (as per Figures 15B-15D), which are part of the perturbator. It is possible to couple the perturbator 60 to the electric circuitry 50 such that it is integrated with just one 30 of the battery cables 52, 54, i.e. one of the positive battery cable 52 or the negative battery cable 54. This is shown in Figures 7A and 7B. Specifically, in Figure 7A, a straight cable portion of only the positive battery cable 52 is threaded through the transmitter coil 64 of the perturbator 60, while in Figure 7B, a coiled cable portion 56 of only the positive battery cable 52 is placed in abutment with the transmitter coil 64. 35 It is envisaged that the configurations of Figures 16A and 16B may be enclosed inside the housing of the perturbator 60, and the perturbator may comprise the cable portions (e,g, as per Figures 10A-10B where the perturbator 60 comprises cable portions 65). Specifically, the perturbator 60 may comprise the straight cable portion which is threaded through the opening 75 of the transmitter coil 64 (as per Figure 16A) or the coiled cable portion which is placed in abutment with the transmitter coil 64 (as per Figure 40 16B). It is also possible to couple the perturbator 60 to the electric circuitry 50 such that it is integrated with both of the positive battery cable 52 and the negative battery cable 54. This is shown in Figures 8A and 8B. In 10 15 CM20 CXI 25 Figure 8A, the positive battery cable 52 and the negative battery cable 54 are each threaded through a respective transmitter coil 64 of the perturbator 60. In Figure 8B, each of the positive and the negative battery cable 54 comprises a coiled cable portion 56 (comprising just one turn), and each coiled cable portion 56 is placed on top of a respective transmitter coil 64 of the perturbator 60. It is envisaged that the configurations of Figures 17A and 17B may be enclosed inside the housing of the perturbator 60, and the perturbator may comprise the cable portions (e,g, as per Figures 10A-10B where the perturbator 60 comprises cable portions 65). Thus, the perturbator 60 may comprise a pair of straight cable portions 65 (positive and negative) threaded through the openings 75 of the transmitter coils 64 (as per Figure 17A) or a pair of coiled cable portions (positive and negative) placed in abutment with the transmitter coils 64 (as per 17B). It is possible that the perturbator 60 comprises a plurality of transmitter coils 64 which sandwich a plurality of coiled cable portions 56 of the electric circuitry 50. This is shown in Figure 18. In the example of Figure 18, the perturbator 60 comprises 4 transmitter coils 64 alternately arranged with 3 coiled cable portions 56 of the electric circuitry 50. Each coiled cable portion 56 is sandwiched between a respective pair of the transmitter coils 64. It is envisaged that the configurations of Figure 18 may be enclosed inside the housing of the perturbator 60, and the perturbator 60 may comprise the coiled cable portions (e,g, as per Figures 10A-10B where the perturbator 60 comprises cable portions 65). Thus, the perturbator 60 may comprise a plurality of (e.g. three) coiled cable portions 65 alternately arranged with a plurality of (e.g. four) transmitter coils 64 such that each coiled cable portions 65 is sandwiched between a respective pair of transmitter coils 64 as per Figure 18. In some examples, the one or more receiver coils 66 may be interwound with the one or more transmitter coils 64 in single coil, as shown in Figure 19. The wires of the receiver 66 and the transmitter coils 64 are covered with an electrically insulating material, such as enamel, such that the wires of the receiver coils and transmitter coils can touch without conducting electricity from one another. In this way, the transmitter 64 and receiver 66 coils can be closely wound together in a single, compact coil which can be enclosed within the perturbator housing. Figures 20A-20D show an implementation of the perturbator 60 according to the present disclosure in which the perturbator 60 comprises a magnetic field guide 90. The magnetic field guide 90 is formed of a 30 ferromagnetic material and comprises a stadium-shaped frame 92. The perturbator 60 of this example comprises two transmitter coils 64 and two receiver coils 66. Each receiver coil 66 is configured to be coupled to a respective one of the transmitter coils 64 to receive magnetic flux therefrom. The transmitter and receiver coil 66 which are configured to be coupled to one another are wound around opposing limbs 94, 96 of the frame 92. The two receiver coils 66 can be wound around the same limb 96 of the frame 92 35 and the two transmitter coils 64 can be wound around the opposing, same limb 94 of the frame 92, as shown in Figures 20A-20D, 21A and 21C, or the two receiver coils 66 can be wound around opposing limbs 94, 96 of the frame 92, and the two transmitter coils 64 can also be wound around opposing limbs 94, 96 of the frame 92, as shown in Figure 21B. Figures 21A-21B show variant arrangements of the perturbator 60 of Figures 20A-20D connected to the 40 electric circuitry 50 of the BMS 100. In Figure 20A, the transmitter coils 64 are wound around the same limb 94 of the magnetic field guide 90, while the receiver coils 66 are wound around the opposing limb 96. The transmitter coils 64 are each coupled to the power supply 80. In this example, the power supply 80 comprises a first power supply and a second power supply, each configured to supply respective different current signals (waveforms) to 5 their respective transmitter coils 64. In this way, the perturbator 60 can be tuned via waveform control to produce asymmetric or ‘biased’ perturbations. It is also envisaged that the power supply 80 may be a single power supply configured to supply respective different current signals (waveforms) to their respective transmitter coils 64. It is also envisaged that the perturbator 60 may comprise two or more transmitter coils 64 (such as just two transmitter coils) which may be wound around opposing limbs 94, 96 10 of the magnetic field guide 90. The magnetic fields produced by the transmitter coils 64 may interfere to generate the changing magnetic field of the perturbator 60, which is a superposition of the individual magnetic field waveforms. In some examples, the transmitter coils 64 are configured to generate respective different magnetic field waveforms. In Figure 20B, the transmitter coils 64 are wound around opposing limbs 94, 96 of the magnetic field 15 generator 67. The receiver coils 66 are also wound around opposing limbs 94, 96 of the magnetic field generator 67. The two transmitter coils 64 are diagonally spaced from each other relative to the opposing limbs 94, 96, and so are the receiver coils 66. Thus, each receiver coil 66 is separated from its LO corresponding transmitter coil 64 by the shortest distance across the two limbs. CM In Figure 20C, the transmitter coils 64 are switched off (as the power supply 80 is switched off) and the ^■^20 magnetic field guide 90 is used passively to filter current spikes during charge / discharge. The features disclosed in the foregoing description, or In the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, 1— or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. 25 While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention. 30 For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations. Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. 35 Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. CXI CXI It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular 5 value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / -10%.

Claims

25Claims:

1. A battery management system comprising:one or more batteries;electric circuitry electrically connected to the one or more batteries, and further connectable to a5 power source for charging and / or to an electrical load for discharging; anda perturbator comprising a magnetic field generator configured to generate a changing magnetic field, the perturbator being couplable to the electric circuitry to perturb electromagnetic energy within the electric circuitry using the generated changing magnetic field;wherein perturbing the electromagnetic energy within the electric circuitry includes: restricting a10 flow of current through the circuitry and / or perturbing a voltage within the circuitry and / or altering a magnitude and / or direction and / or rate of electric current through the circuitry.

2. The battery management system of claim 1 wherein the perturbator is reversibly couplable to the electric circuitry.

153. The battery management system of claim 1 or 2, wherein the magnetic field generator comprises at least one transmitter coil to generate the changing magnetic field.

4. The battery management system of claim 3 wherein the perturbator comprises a plurality of20 transmitter coils arranged so as to sandwich one or more cable portions.

5. The battery management system of claim 4, wherein the plurality of transmitter coils is arranged alternately with a plurality of cable portions.25 6. The battery management system of claim 3 wherein the at least one transmitter coils is arrangedso as to face or abut one or more cable portions.

7. The battery management system of any one of claims 3 to 6 wherein the electric circuitry comprises the cable portion(s).

308. The battery management system of any one of claims 3 to 6 wherein the perturbator comprises the cable portion(s), the cable portion(s) being electrically connectable to the electric circuitry.

9. The battery management system of claim 7 or 8 wherein the cable portion(s) include at least one 35 straight cable portion and / or at least one coiled cable portion comprising at least one turn.

10. The battery management system of claim 9, wherein the at least one coiled cable portion is coiled around a portion of the at least one transmitter coil.12 06 2511. The battery management system of claim 9 or 10, wherein the at least one straight cable portionis threaded through a core of the at least one transmitter coil.

12. The battery management system of any one of claims 3 to 11, wherein:5 the perturbator comprises a plurality of transmitter coils,the battery management system comprises a power supply for powering the perturbator, and the power supply is configured to supply respective different current signals to respective different transmitter coils.10 13. The battery management system of any one of the preceding claims, wherein the perturbator iswirelessly couplable to the electric circuitry such that a at least a portion of the electric circuitry is placed within the changing magnetic field generated by the magnetic field generator.

14. The battery management system of claim 13, wherein the perturbator is shaped and sized so as 15 to at least partially surround a portion of the electric circuitry.

15. The battery management system of claim 14, wherein the perturbator defines an opening for receiving a portion of the electric circuitry20 16. The battery management system of claim 15, wherein the perturbator comprises a pair of jawsmovable between a closed configuration in which the jaws are in contact to define the opening, and an open configuration in which the jaws are spaced from one another to allow insertion of the portion of the circuitry into the opening.25 17. The battery management system of any one of claims 1 to 12 wherein the perturbator iselectrically connectable to the electric circuitry via a wired connection.

18. The battery management system of claim 17 wherein the magnetic field generator comprises one or more transmitter coils and one or more receiver coils coupled to the one or more transmitter coils to30 receive magnetic field(s) generated by the one or more transmitter coils.

19. The battery management system of claim 18, wherein the one or more receiver coils are electrically connectable to the circuitry to supply electric current thereto.35 20. The battery management system of claim 18 or 19, wherein the perturbator comprises amagnetic field guide comprising a frame, wherein the one or more receiver coils and / or one or more transmitter coils are mounted to the frame.12 06 2521. The battery management system of claim 20 wherein the frame comprises a pair of opposing limbs, and the one or more receiver coils are mounted to one of the opposing limbs, and the one or more transmitter coils are mounted to the other of the opposing limbs.5 22. The battery management system of any one of the preceding claims, wherein the batterymanagement system further comprises a measurement unit configured to obtain measurements on the electric circuitry and / or the one or more batteries during operation of the electric circuitry and the perturbator.10 23. A perturbator for use with the battery management system of any one of the preceding claims,the perturbator comprising:a magnetic field generator configured to generate a changing magnetic field;wherein the perturbator is couplable to electric circuitry to perturb electromagnetic energy within the circuitry using the changing magnetic field.1524. A method of perturbing electromagnetic energy within electric circuitry using a perturbator, the perturbator comprising:a magnetic field generator configured to generate a changing magnetic field, wherein the current perturbator is couplable to electric circuitry to perturb electromagnetic energy within the circuitry 20 using the changing magnetic field,the method comprising:coupling the perturbator to the electric circuitry; andgenerating the changing magnetic field to perturb the electromagnetic energy within the electric circuitry, wherein perturbing the electromagnetic energy within the electric circuitry includes: restricting a 25 flow of current through the circuitry and / or perturbing a voltage within the circuitry and / or altering a magnitude and / or direction and / or rate of electric current through the circuitry.s

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