A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

An ultra-low temperature and high-capacity primary lithium battery and a preparation method thereof. The primary lithium battery includes a dry cell, an electrolyte and a case. The battery is made by placement of the dry cell into the case, injection of the electrolyte, primary aging, sealing and secondary aging successively. The dry cell includes multiple unit sub-cells, and each unit sub-cell is repeated lamination of a positive plate, separator, a negative plate and another separator or lamination and winding. All unit sub-cells are enclosed such that the heat generated by the primary lithium battery during operation circulates inside the battery.

An electrochemical cell that converts chemical energy to electrical energy includes a cathode with an active material of fluorinated carbon on a perforated metal cathode current collector, a lithium anode on a perforated metal anode current collector, a stepped header, a stable electrolyte, and a separator. In various embodiments, an anode current collector design, a cathode current collector design, a stepped header design, a cathode formulation, an electrolyte formulation, a separator, and a battery incorporating the electrochemical cell are provided.

A lithium primary cell includes an electrode group and a non-aqueous electrolytic solution. The electrode group includes a positive electrode, a negative electrode, and a separator, in which the positive electrode and the negative electrode are wound with the separator interposed therebetween. In the electrode group, an area where the positive electrode and the negative electrode face each other is 250 cm.sup.2 or more and 350 cm.sup.2 or less. The positive electrode includes a positive electrode mixture including manganese dioxide and a boron compound. The negative electrode includes lithium metal or a lithium alloy. The non-aqueous electrolytic solution includes ethylene carbonate. A content of the boron compound in the positive electrode is 0.5 parts by mass or more and 2 parts by mass or less in terms of boron with respect to 100 parts by mass of the positive electrode mixture. A content of the ethylene carbonate in the non-aqueous electrolytic solution is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the manganese dioxide.

An electrochemical cell that converts chemical energy to electrical energy includes a cathode with an active material of fluorinated carbon on a perforated metal cathode current collector, a lithium anode on a perforated metal anode current collector, a stepped header, a stable electrolyte, and a separator. In various embodiments, an anode current collector design, a cathode current collector design, a stepped header design, a cathode formulation, an electrolyte formulation, a separator, and a battery incorporating the electrochemical cell are provided.

A method of forming a package is provided and includes providing two laminate edge portions of the package, each of which includes a foil layer between first and second resin layers; and welding together the respective first resin layers at a first position spaced apart from the edges while not welding the respective first resin layers at the edges, wherein the edge portions include edges from which electrode terminals extend such that portions of the electrode terminals are exposed beyond the edges, and wherein the edge portions are between a sealing portion and exposed portions of positive and negative electrode terminals.

A method of forming a package is provided and includes providing two laminate edge portions of the package, each of which includes a foil layer between first and second resin layers; and welding together the respective first resin layers at a first position spaced apart from the edges while not welding the respective first resin layers at the edges, wherein the edge portions include edges from which electrode terminals extend such that portions of the electrode terminals are exposed beyond the edges, and wherein the edge portions are between a sealing portion and exposed portions of positive and negative electrode terminals.

The hybrid battery system has multiple discharge voltage plateaus and a greater charge capacity of metal in the negative electrode, while still having sufficient energy density and sufficient power capability to supply external devices. The charge capacity of the negative side is higher than the charge capacity of the positive side. There are two solvent compositions in the cathodic solution, and there is a transition from a first discharge voltage plateau to a second discharge voltage plateau at a voltage less than the first discharge voltage plateau. The battery system is safe, and the transition between discharge voltage plateaus provides an estimation of battery capacity that can indicate when the battery system is running out of power.

A method of forming a package is provided and includes providing two laminate edge portions of the package, each of which includes a foil layer between first and second resin layers; and welding together the respective first resin layers at a first position spaced apart from the edges while not welding the respective first resin layers at the edges, wherein the edge portions include edges from which electrode terminals extend such that portions of the electrode terminals are exposed beyond the edges, and wherein the edge portions are between a sealing portion and exposed portions of positive and negative electrode terminals.

A method of forming a package is provided and includes providing two laminate edge portions of the package, each of which includes a foil layer between first and second resin layers; and welding together the respective first resin layers at a first position spaced apart from the edges while not welding the respective first resin layers at the edges, wherein the edge portions include edges from which electrode terminals extend such that portions of the electrode terminals are exposed beyond the edges, and wherein the edge portions are between a sealing portion and exposed portions of positive and negative electrode terminals.