Abstract: An energy storage device includes a battery with at least one battery cell and two poles, two connection points each connected to battery pole, for connecting to an external current circuit for charging and discharging the battery, a battery charge state monitoring device, an additional energy storage element different than the battery cell, a connection circuit for connecting the additional energy storage element to at least one battery pole, and at least one connection point. The connection circuit is designed such that a specified energy storage element current having a specified relationship with the total current flowing through the energy storage device is charged into and/or discharged from the energy storage element. A voltage measuring device contacts the additional energy storage element to measure an energy storage voltage, and the charge state monitoring device determines the charge state of the battery based at least on the energy storage voltage.

Abstract: A method for determining a charge state of an electric energy store, having the following steps: measuring a voltage of the electric energy store on the basis of a charge quantity which is removed from or supplied to the electric energy store as a voltage characteristic curve and ascertaining a virtual open-circuit voltage characteristic curve from the measured voltage using at least one operating parameter of the electric energy store, ascertaining a first derivative and/or a second derivative of the virtual open-circuit voltage characteristic curve according to the charge quantity removed from or supplied to the electric energy store, detecting at least one characteristic of the first derivative and/or the second derivative of the virtual open-circuit voltage characteristic curve, and determining the charge state of the electric energy store using the detected at least one characteristic, is provided.

Abstract: A process produces a connecting structure between two superconductors, in particular magnesium diboride superconductors embodied as a superconducting core wire surrounded by normally conducting metal. A substance which reduces the melting point of magnesium is admixed to a substance mixture including magnesium and boron, and the exposed ends of the core wires are brought into contact with the substance mixture, which is caused to react in situ at a reaction temperature corresponding to the lower melting point to give magnesium diboride.

Abstract: A superconductive connecting device of at least one embodiment is used to contact the end pieces of two superconductors, each of which includes at least one conductor lead that is made of a superconductive MgB2 material and embedded in a matrix made of a normally conductive material, the conductor lead being directly sheathed with a barrier material. In a connecting region, the conductor leads of the end pieces, which are at least partially stripped of the matrix material and the barrier material, are arranged inside a sleeve or bushing, and a magnesium diboride (MgB2) material is additionally present as a superconductive contacting material which is located at least in some partial regions between the conductor leads. For establishing the connection, the cross-section of the sleeve or bushing filled in this way is reduced.

Abstract: A process produces a connecting structure between two superconductors, in particular magnesium diboride superconductors embodied as a superconducting core wire surrounded by normally conducting metal. A substance which reduces the melting point of magnesium is admixed to a substance mixture including magnesium and boron, and the exposed ends of the core wires are brought into contact with the substance mixture, which is caused to react in situ at a reaction temperature corresponding to the lower melting point to give magnesium diboride.

Abstract: A superconductive connecting device of at least one embodiment is used to contact the end pieces of two superconductors, each of which includes at least one conductor lead that is made of a superconductive MgB2 material and embedded in a matrix made of a normally conductive material, the conductor lead being directly sheathed with a barrier material. In a connecting region, the conductor leads of the end pieces, which are at least partially stripped of the matrix material and the barrier material, are arranged inside a sleeve or bushing, and a magnesium diboride (MgB2) material is additionally present as a superconductive contacting material which is located at least in some partial regions between the conductor leads. For establishing the connection, the cross-section of the sleeve or bushing filled in this way is reduced.