THE FURUKAWA BATTERY CO., Ltd.

A lithium ion secondary battery includes a negative electrode including a mixture layer which contains a niobium titanium oxide as a negative electrode active material, and non-aqueous electrolyte containing lithium alkoxysulfonate represented by RSOOO − Li + (where R is at least one selected from the group consisting of OCH 3 and OC 2 H 5 ).

A bipolar lead-acid storage battery has both life performance to withstand long-term operation and high capacity performance. Positive electrode current collector plates include a lead alloy sheet, a mass loss per total surface area of a test piece is 100 mg/cm 2 or less when measured after the test piece is placed in sulfuric acid at a concentration of 38 mass % maintained at a temperature of 60° C., and a continuous anodization performed at a constant potential of 1,350 mV on a reference electrode for 28 days. A thickness of the collector plate arranged on one surface of a substrate that covers both a side of a positive electrode and a side of a negative electrode of a cell member is between 0.10 mm and 0.50 mm, and a ratio of a volume of the current collector plate to a rated capacity of the battery is between 0.11 and 0.67.

A bipolar battery includes a plurality of cell members, each including a positive electrode having a positive active material layer, a negative electrode having a negative active material layer, and an electrolyte layer interposed between the positive electrode and the negative electrode. The bipolar battery also includes a plurality of frame units respectively forming a plurality of cells respectively incorporating the plurality of cell members. Each of the plurality of frame units is a frame unit made of a light transmissive resin material. Two of the frame units made of the light transmissive resin material adjacent in a stacking direction of the cell members are welded and joined at a welded portion via a joining member made of a light absorbing resin material. This configuration can provide a bipolar battery capable of reliably preventing electrolytic solution leakage out of a cell by means of a simple seal structure.

A lead alloy is described that is capable of manufacturing a positive electrode for a lead storage battery less likely to cause corrosion penetrating through a lead layer for the positive electrode in the thickness direction. The lead alloy contains 0.4% by mass or more and 2% by mass less of tin and 0.004% by mass or less of bismuth, with the balance being lead and inevitable impurities. When image analysis of a crystal orientation distribution map created by analyzing the surface of the lead alloy by an electron backscatter diffraction method is performed, intersection points of misorientation boundaries between crystal grains with a crystal misorientation of 5° or more and a straight line extending in one specific direction are extracted. The distances between two adjacent intersection points among the extracted intersection points are measured, and the average value of the distances is 50 μm or less.