Abstract: The present invention concerns a fire safety arrangement for a battery. More particularly, but not exclusively, this invention concerns a fire safety arrangement for a metal ion battery, for example a lithium ion battery cell. The metal ion battery cell comprises a plurality of electrodes and an electrolyte encased within a housing. The housing comprises a safety valve or vent to allow gas build up within the housing to vent outside the housing, and a fabric envelope surrounding the housing. Any sparks generated by the battery are contained within the fabric envelope, thereby reducing or eliminating the chances of fire or explosion.

Abstract: A method of controlling a wireless power transfer system. The wireless power transfer system comprises an electromagnetic induction charger operable to emit electromagnetic radiation into an environment of the charger, motion sensor equipment operable to generate an output indicating whether or not a moving object is present in the environment, and a controller. The controller is configured to receive the output from the motion sensor equipment, determine whether the received output indicates that a moving object is present in a predefined region of the environment, and in response to a positive determination, prevent the charger from emitting electromagnetic radiation.

Abstract: A method of controlling a wireless power transfer system comprising a primary stage and a secondary stage is provided. The primary stage comprises a DC/DC converter configured to generate a DC output, a DC/AC inverter configured to receive the DC output and to generate an AC output according to a variable switching frequency, and a primary coil configured to transfer power to the secondary stage in response to the DC/AC inverter generating the AC output. The switching frequency of the DC/AC inverter is adjusted to cause a phase angle between an input current and an input voltage of the primary coil to be less than or equal to a predetermined threshold. The DC output of the DC/DC converter is controlled to cause a desired amount of power to be transferred from the primary coil at the adjusted switching frequency.

Abstract: An electrical transformer and method of manufacturing an electrical transformer. The electrical transformer comprises a set of primary windings comprising first and second primary windings connected in parallel and first and second sets of secondary windings. Each of the first and second sets comprises a plurality of secondary windings that are connected in parallel. The secondary windings of the first set are electrically isolated from the secondary windings of the second set. The set of primary windings and the first and second sets of secondary windings are arranged in a stacked structure in which the secondary windings of the first set are interleaved with the secondary windings of the second set, and at least one secondary winding of the first set and/or at least one secondary winding of the second set is arranged between the first and second primary windings.

Abstract: An AC/DC power converter includes an input port configured to receive an AC power signal, a first transformer coupled to the input port, the first transformer comprising first and second primary windings and at least a first secondary winding, and a second transformer coupled to the input port, the second transformer comprising third and fourth primary windings and at least a second secondary winding. The first primary winding of the first transformer is coupled in series with the third primary winding of the second transformer, the second primary winding of the first transformer is coupled in series with the fourth primary winding of the second transformer, and the first secondary winding and the second secondary winding are coupled in parallel.