The negative electrode plate 16, that is, the titanium-containing sintered plate has a structure that a plurality (namely, a large number) of primary grains are bonded. Accordingly, these primary grains are preferably composed of LTO or Nb₂TiO₇.

The negative electrode plate 16 preferably has a thickness of 70 to 500 μm, preferably 85 to 400 μm, more preferably 95 to 350 μm. The larger the thickness of the LTO sintered plate, a battery with high capacity and high energy density is achieved more easily. The thickness of the negative electrode plate 16 is determined by measuring the distance between the two substantially parallel faces of the plate, for example, when the cross section of the negative electrode plate 16 is observed by SEM (scanning electron microscopy).

The primary grain size that is the average grain size of the plurality of primary grains forming the negative electrode plate 16 is preferably 1.2 μm or less, more preferably 0.02 to 1.2 μm, further preferably 0.05 to 0.7 μm. Within such a range, the lithium ion conductivity and the electron conductivity are easily compatible with each other, which contributes to improving the rate performance.

The negative electrode plate 16 preferably contains pores. The electrolytic solution can penetrate into the sintered plate by the sintered plate including pores, particularly open pores, when the sintered plate is integrated into a battery as a negative electrode plate. As a result, the lithium ion conductivity can be improved. This is because there are two types of conduction of lithium ions within the sintered body: conduction through constituent grains of the sintered body; and conduction through the electrolytic solution within the pores, and the conduction through the electrolytic solution within the pores is overwhelmingly faster.