A feed-through, in particular a feed-through which passes through part of a housing, in particular a battery housing, for example made of metal, in particular light metal, for example aluminum, an aluminum alloy, AlSiC, magnesium, an magnesium alloy, titanium, a titanium alloy, steel, stainless steel or high-grade steel. The housing part has at least one opening through which at least one conductor, in particular an essentially pin-shaped conductor, embedded in a glass or glass ceramic material, is guided. The base body is, for example, an essentially annular-shaped base body.

A feed-through, for example a battery feed-through for a lithium-ion battery or a lithium ion accumulator, has at least one base body which has at least one opening through which at least one conductor, for example a pin-shaped conductor, embedded in a glass material is guided. The base body contains a low melting material, for example a light metal, such as aluminum, magnesium, AlSiC, an aluminum alloy, a magnesium alloy, titanium, titanium alloy or steel, in particular special steel, stainless steel or tool steel. The glass material consists of the following in mole percent: 35-50% P.sub.2O.sub.5; 0-14% Al.sub.2O.sub.3; 2-10% B.sub.2O.sub.3; 0-30% Na.sub.2O; 0-20% M.sub.2O, with M being K, Cs or Rb; 0-35% Li.sub.2O; 0-20% BaO; and 0-10% Bi.sub.2O.sub.3, the glass material being free of lead except for contaminants.

A feed-through, for example a battery feed-through for a lithium-ion battery or a lithium ion accumulator, has at least one base body which has at least one opening through which at least one conductor, for example a pin-shaped conductor, embedded in a glass material is guided. The base body contains a low melting material, for example a light metal, such as aluminum, magnesium, AlSiC, an aluminum alloy, a magnesium alloy, titanium, titanium alloy or steel, in particular special steel, stainless steel or tool steel. The glass material consists of the following in mole percent: 35-50% P.sub.2O.sub.5; 0-14% Al.sub.2O.sub.3; 2-10% B.sub.2O.sub.3; 0-30% Na.sub.2O; 0-20% M.sub.2O, with M being K, Cs or Rb; 0-35% Li.sub.2O; 0-20% BaO; and 0-10% Bi.sub.2O.sub.3, the glass material being free of lead except for contaminants.

A feedthrough, for example through a part of a housing, such as a battery housing, is, for example, made of a metal, such as a light alloy, for example aluminum, an aluminum alloy, AlSiC, magnesium, a magnesium alloy, titanium, a titanium alloy, steel, stainless steel or high-grade steel. The housing part has at least one opening through which at least one conductor having a cross-section is guided in a glass or glass ceramic material. The conductor has at least two sections, a first section having a first, substantially round, for example a circular, cross section having a diameter in the region of the feedthrough through the glass or glass ceramic material, and a second section having a second, substantially non-round, for example a substantially rectangular cross-section, and the conductor is formed in one piece.

A feedthrough, for example through a part of a housing, such as a battery housing, is, for example, made of a metal, such as a light alloy, for example aluminum, an aluminum alloy, AlSiC, magnesium, a magnesium alloy, titanium, a titanium alloy, steel, stainless steel or high-grade steel. The housing part has at least one opening through which at least one conductor having a cross-section is guided in a glass or glass ceramic material. The conductor has at least two sections, a first section having a first, substantially round, for example a circular, cross section having a diameter in the region of the feedthrough through the glass or glass ceramic material, and a second section having a second, substantially non-round, for example a substantially rectangular cross-section, and the conductor is formed in one piece.

A feed-through, for example a battery feed-through for a lithium-ion battery or a lithium ion accumulator, has at least one base body which has at least one opening through which at least one conductor, for example a pin-shaped conductor, embedded in a glass material is guided. The base body contains a low melting material, for example a light metal, such as aluminum, magnesium, AlSiC, an aluminum alloy, a magnesium alloy, titanium, titanium alloy or steel, in particular special steel, stainless steel or tool steel. The glass material consists of the following in mole percent: 35-50% P.sub.2O.sub.5, for example 39-48%; 0-14% Al.sub.2O.sub.3, for example 2-12%; 2-10% B.sub.2O.sub.3, for example 4-8%; 0-30% Na.sub.2O, for example 0-20%; 0-20% M.sub.2O, for example 12-20%, wherein M is K, Cs or Rb; 0-10% PbO, for example 0-9%; 0-45% Li.sub.2O, for example 0-40% or 17-40%; 0-20% BaO, for example 5-20%; 0-10% Bi.sub.2O.sub.3, for example 1-5% or 2-5%.

A feed-through, for example a battery feed-through for a lithium-ion battery or a lithium ion accumulator, has at least one base body which has at least one opening through which at least one conductor, for example a pin-shaped conductor, embedded in a glass material is guided. The base body contains a low melting material, for example a light metal, such as aluminum, magnesium, AlSiC, an aluminum alloy, a magnesium alloy, titanium, titanium alloy or steel, in particular special steel, stainless steel or tool steel. The glass material consists of the following in mole percent: 35-50% P.sub.2O.sub.5, for example 39-48%; 0-14% Al.sub.2O.sub.3, for example 2-12%; 2-10% B.sub.2O.sub.3, for example 4-8%; 0-30% Na.sub.2O, for example 0-20%; 0-20% M.sub.2O, for example 12-20%, wherein M is K, Cs or Rb; 0-10% PbO, for example 0-9%; 0-45% Li.sub.2O, for example 0-40% or 17-40%; 0-20% BaO, for example 5-20%; 0-10% Bi.sub.2O.sub.3, for example 1-5% or 2-5%.

A method for producing a mirror substrate of an optical element for a projection exposure apparatus, in particular an EUV projection exposure apparatus, comprising a first and at least one second component, wherein the first component and the at least one second component consist of silicon at least on a side facing a connection, and the method includes the following steps: providing/producing the at least two components of the mirror substrate and joining the at least two components by heating to a joining temperature and applying a joining pressure, preferably perpendicular to a joining surface.

A method for producing a mirror substrate of an optical element for a projection exposure apparatus, in particular an EUV projection exposure apparatus, comprising a first and at least one second component, wherein the first component and the at least one second component consist of silicon at least on a side facing a connection, and the method includes the following steps: providing/producing the at least two components of the mirror substrate and joining the at least two components by heating to a joining temperature and applying a joining pressure, preferably perpendicular to a joining surface.