Abstract: A battery pack includes a first core pack and a second core pack each holding a plurality of unit cells. The unit cells of a first cell group or second cell group that is closest to a connector are electrically connected to the connector through a third busbar. The unit cells of the first cell group or second cell group that is most distant from the connector are electrically connected to the connector through a fourth busbar.

Abstract: A battery pack includes a first core pack and a second core pack each holding a plurality of unit cells. The unit cells of one of first cell groups (or second cell groups) in each of the first core pack and the second core pack are electrically connected to a connector through a positive-side connection busbar and a negative-side connection busbar, respectively. Vertically adjacent cell groups are electrically connected to each other through cell group interconnection busbars. Insulator is interposed between the mutually facing cell group interconnection busbars that present a largest potential difference.

Abstract: A battery pack includes a first core pack and a second core pack each holding a plurality of unit cells. The unit cells of one of first cell groups (or second cell groups) in each of the first core pack and the second core pack are electrically connected to a connector through a positive-side connection busbar and a negative-side connection busbar, respectively. Vertically adjacent cell groups are electrically connected to each other through cell group interconnection busbars. Insulator is interposed between the mutually facing cell group interconnection busbars that present a largest potential difference.

Abstract: A battery pack includes a first core pack and a second core pack each holding a plurality of unit cells. The unit cells of a first cell group or second cell group that is closest to a connector are electrically connected to the connector through a third busbar. The unit cells of the first cell group or second cell group that is most distant from the connector are electrically connected to the connector through a fourth busbar.

Abstract: Provided is an electrode mixture layer capable of reducing internal resistance by use of a carbon nanotube molding. The electrode mixture layer includes an active material and a conductor of carbon nanotubes in close contact with the surface of the active material, and the number density of the carbon nanotubes is 4 tubes/?m or more. The number density is defined as a value obtained by providing measurement lines on a scanning electron microscope image of a surface of the electrode mixture layer at 0.3 ?m intervals both longitudinally and laterally, measuring the total number of the carbon nanotubes being in close contact with the surface of the active material and intersecting the measurement lines, and dividing the total number of the carbon nanotubes by the total length of the measurement lines on the active material surface.

Abstract: Provided is an electrode for a secondary cell capable of obtaining excellent output values and input values when used in the secondary cell. The electrode for a secondary cell is formed of an electrode mixture layer molded body formed of an active material and at least one of a carbon nanotube and a three-dimensional carbon nanotube fiber bundle skeleton formed of a plurality of carbon nanotubes that intersect one another to form an aggregation, which are in intimate contact with the surface of the active material; and a current collector layered on the electrode mixture layer molded body. The electrode mixture layer molded body includes a first roughened surface, and the current collector includes a second roughened surface. The first roughened surface of the electrode mixture layer molded body and the second roughened surface of the current collector are pressed and attached to each other.

Abstract: Provided is an electrode for a secondary cell capable of obtaining excellent output values and input values when used in the secondary cell. The electrode for a secondary cell is formed of an electrode mixture layer molded body formed of an active material and at least one of a carbon nanotube and a three-dimensional carbon nanotube fiber bundle skeleton formed of a plurality of carbon nanotubes that intersect one another to form an aggregation, which are in intimate contact with the surface of the active material; and a current collector layered on the electrode mixture layer molded body. The electrode mixture layer molded body includes a first roughened surface, and the current collector includes a second roughened surface. The first roughened surface of the electrode mixture layer molded body and the second roughened surface of the current collector are pressed and attached to each other.

Abstract: Provided is an electrode mixture layer capable of reducing internal resistance by use of a carbon nanotube molding. The electrode mixture layer includes an active material and a conductor of carbon nanotubes in close contact with the surface of the active material, and the number density of the carbon nanotubes is 4 tubes/?m or more. The number density is defined as a value obtained by providing measurement lines on a scanning electron microscope image of a surface of the electrode mixture layer at 0.3 ?m intervals both longitudinally and laterally, measuring the total number of the carbon nanotubes being in close contact with the surface of the active material and intersecting the measurement lines, and dividing the total number of the carbon nanotubes by the total length of the measurement lines on the active material surface.