A rechargeable metal halide battery with an optimized active cathode electrolyte solution has high energy density and does not require charging following fabrication. The optimized active cathode electrolyte solution includes (i) a mixture of a metal halide and its corresponding halogen dissolved in an organic solvent at a concentration ratio greater than 0.5 and (ii) an oxidizing gas. The organic solvent is a nitrile-based compound and/or a heterocyclic compound. Glyme may be added to the organic solvent to improve battery performance.

A rechargeable metal halide battery with an optimized active cathode electrolyte solution has high energy density and does not require charging following fabrication. The optimized active cathode electrolyte solution includes (i) a mixture of a metal halide and its corresponding halogen dissolved in an organic solvent at a concentration ratio greater than 0.5 and (ii) an oxidizing gas. The organic solvent is a nitrile-based compound and/or a heterocyclic compound. Glyme may be added to the organic solvent to improve battery performance.

A technology capable of sealing a target with higher airtightness is provided. The plug attaching device disclosed herein is for attaching, to a through hole of a target, a cylindrical plug having therein a non-through hole that has an opening in one end surface. The device includes an insertion pin, and a guide portion. The guide portion is slidable in the axial direction of the insertion pin. This device is configured such that the plug is disposed inside the through hole, the insertion pin is pushed into the non-through hole with the guide portion disposed on the periphery of the opening to attach the plug into the through hole, and after the attachment, the insertion pin is moved in an opposite direction to the non-through hole to remove the insertion pin from the non-through hole, and the guide portion is then detached from the opening.

A technology capable of sealing a target with higher airtightness is provided. The plug attaching device disclosed herein is for attaching, to a through hole of a target, a cylindrical plug having therein a non-through hole that has an opening in one end surface. The device includes an insertion pin, and a guide portion. The guide portion is slidable in the axial direction of the insertion pin. This device is configured such that the plug is disposed inside the through hole, the insertion pin is pushed into the non-through hole with the guide portion disposed on the periphery of the opening to attach the plug into the through hole, and after the attachment, the insertion pin is moved in an opposite direction to the non-through hole to remove the insertion pin from the non-through hole, and the guide portion is then detached from the opening.

An all solid storage element laminate that has a plurality of all solid storage elements disposed in a matrix, and includes a plurality of element layers laminated in a thickness direction. The all solid storage elements of element layers adjacent to each other in a thickness direction are electrically connected to each other.

A negative-electrode terminal that is secured to a sealing plate is connected to a first negative-electrode current collector. A negative-electrode tab that is connected to the negative-electrode sheet is connected to a second negative-electrode current collector. The first negative-electrode current collector and the second negative-electrode current collector are disposed along the sealing plate. The second negative-electrode current collector has an opening. The second negative-electrode current collector is disposed on the first negative-electrode current collector such that the opening faces the first negative-electrode current collector. The second negative-electrode current collector is welded to the first negative-electrode current collector around the opening.

A negative-electrode terminal that is secured to a sealing plate is connected to a first negative-electrode current collector. A negative-electrode tab that is connected to the negative-electrode sheet is connected to a second negative-electrode current collector. The first negative-electrode current collector and the second negative-electrode current collector are disposed along the sealing plate. The second negative-electrode current collector has an opening. The second negative-electrode current collector is disposed on the first negative-electrode current collector such that the opening faces the first negative-electrode current collector. The second negative-electrode current collector is welded to the first negative-electrode current collector around the opening.

Provided is a microporous film which has a surface A and a surface B opposite to the surface A. In one embodiment, the microporous film has a ratio (F.sub.B/F.sub.A) of a dynamic friction coefficient F.sub.B of the surface B to a dynamic friction coefficient F.sub.A of the surface A of 1.2 to 20. In another embodiment, the microporous film is a single layer having a thickness of 3-18 μm, a number N.sub.A of pores on the surface A is 10-100/μm.sup.2, a number N.sub.B of pores on the surface B is 20-200/μm.sup.2, and N.sub.A/N.sub.B is 0.2-0.96. In addition, a total area S.sub.A of pores on the surface A is 0.02-0.5 μm.sup.2/μm.sup.2, a total area S.sub.B of pores on the surface B is 0.01-0.3 μm.sup.2/μm.sup.2, and S.sub.A/S.sub.B is 1.1-10. Furthermore, in another embodiment, a number W.sub.B of protrusion-like bodies on the surface B is 0.2-1000/100 μm.sup.2.

Provided is a method of preparing an irreversible positive electrode additive for a secondary battery, which includes mixing Li.sub.2O, NiO, and NH.sub.4VO.sub.3 and performing thermal treatment to prepare a lithium nickel composite oxide represented by Chemical Formula 1 below, wherein the NH.sub.4VO.sub.3 is mixed in an amount of 1.5 to 6.5 parts by weight with respect to a total of 100 parts by weight of the Li.sub.2O, NiO, and NH.sub.4VO.sub.3.

Li.sub.2+aNi.sub.1−b−cM.sup.1.sub.bV.sub.cO.sub.2−dA.sub.d  [Chemical Formula 1]

In Chemical Formula 1,

M.sup.1 is at least one selected from the group consisting of Cu, Mg, Pt, Al, Co, P, W, Zr, Nb, and B, A is at least one selected from the group consisting of F, S, Cl, and Br, and 0≤a≤0.2, 0≤b≤0.5, 0.01≤c≤0.065, and 0≤d≤0.2 are satisfied.

A non-aqueous electrolyte secondary battery includes an electrode body including a positive electrode plate and a negative electrode plate, a rectangular exterior body having an opening and accommodating the electrode body, a sealing plate sealing the opening, and an electrode terminal provided to the sealing plate. The positive electrode plate includes a positive electrode core and a positive electrode active material applied to both surfaces of the positive electrode core. The peripheral length of a positive electrode core portion to which the positive electrode active material is applied is 0.28 m/Ah or less per unit battery capacity.