An all-solid-state battery cell has a cathode on which a cathode current collector is attached, a solid electrolyte deposited on the cathode opposite the cathode current collector, an anode comprising lithium deposited onto the solid electrolyte opposite the cathode, and an anode current collector bonded to the anode opposite the solid electrolyte with a bonding layer of a metal alloyed with the lithium.

Provided is a bipolar all-solid-state sodium ion secondary battery that can increase the voltage without impairing safety. A bipolar all-solid-state sodium ion secondary battery includes: a plurality of all-solid-state sodium ion secondary batteries 1 in each of which a positive electrode layer 3 capable of absorbing and releasing sodium, a solid electrolyte layer 4 made of a sodium ion-conductive oxide, and a negative electrode layer 5 capable of absorbing and releasing sodium are laid one upon another in this order; and a current collector layer 2 provided between the positive electrode layer 3 of each of the plurality of all-solid-state sodium ion secondary batteries 1 and the negative electrode layer 5 of the adjacent all-solid-state sodium ion secondary battery 1 and shared by the positive electrode layer 3 and the negative electrode layer 5.

Provided are an electrolytic solution suitable for a lithium ion secondary battery that includes a positive electrode which has a positive electrode active material having an olivine structure, and includes a negative electrode having graphite as a negative electrode active material, and a superior lithium ion secondary battery having the electrolytic solution. The lithium ion secondary battery includes: a positive electrode that includes a positive electrode active material having an olivine structure; a negative electrode having graphite as a negative electrode active material; and an electrolytic solution. The electrolytic solution contains LiPF.sub.6, a cyclic alkylene carbonate selected from ethylene carbonate and propylene carbonate, methyl propionate, and an additive that starts reductive degradation at a potential higher than a potential at which the above components of the electrolytic solution start reductive degradation.

Provided is a bipolar current collector, including an insulation film layer, a positive electrode metal layer, and a negative electrode metal layer. The insulation film layer has a first surface and a second surface in a thickness direction. The insulation film layer has a first region portion. In a length direction of the current collector, a part of a first surface located at the first region portion has a first exposed region and a first coated region. A part of a second surface located at the first region portion has a second exposed region and a second coated region. On a symmetry surface, as reference plane, of the insulation film layer in the thickness direction, a projection of the first coated region does not exceed a projection of the second exposed region, and a projection of the second coated region does not exceed a projection of the first exposed region.

A battery plate having a substrate with opposing surfaces and one or more nonplanar structures and one or more active materials disposed on at least one of the opposing surfaces; wherein the battery plate includes one or more of: i) one or more projections disposed within but do not extend beyond the active material; ii) one or more projections which project beyond the active material and substantially free of the active material or dust formed from the active material; and/or iii) a frame about the periphery of the substrate which projects beyond the active material and is substantially free of the active material or dust formed from the active material; and wherein the battery plate is adapted to form part of one or more electrochemical cells in a battery assembly.

To suppress heat generation in a stacked battery including a plurality of electric elements in internal short circuits and an unstable reaction when the battery is operated while an energy level is increased, the stacked battery includes a stack comprising a first current collector layer, a second current collector layer, a plurality of bipolar current collector layers that are arranged between the first and second current collector layers at intervals in the stacking direction, a plurality of electric elements, an anode active material layer, and an electrolyte layer that is arranged between the cathode and anode active material layers, where the ratio h/S (cm.sup.−1) of a length h (cm) between the one end face and the other end face in the stacking direction of the stack to an electrode area S (cm.sup.2) on a cross section orthogonal to the stacking direction of the stack is more than 1.

Embodiments described herein relate generally to electrochemical cells having semi-solid electrodes that are coated on only one side of a current collector. In some embodiments, an electrochemical cell includes a semi-solid positive electrode coated on only one side of a positive current collector and a semi-solid negative electrode coated on only one side of a negative current collector. A separator is disposed between the semi-solid positive electrode and the semi-solid negative electrode. At least one of the semi-solid positive electrode and the semi-solid negative electrode can have a thickness of at least about 250 μm.

A battery includes positive and negative current collectors and a plurality of bipolar electrodes arranged in a stack between the positive and negative current collectors. The positive and negative current collectors and the stack of the plurality of bipolar electrodes are folded in an S-shape.

A partition plate includes a partition substrate, a positive electrode membrane, a negative electrode membrane, and an insulation layer. The positive electrode membrane and the negative electrode membrane are respectively located on two surfaces of the partition substrate. The insulation layer is disposed on the partition substrate and the insulation layer is disposed at a periphery of the positive electrode membrane. A zone surrounded by orthographic projection of an outer edge of the insulation layer on the partition substrate covers orthographic projection of the negative electrode membrane on the partition substrate. This application can improve self-discharge and safety performances of electrochemical apparatuses.

An alkaline storage battery includes a plurality of foil electrodes that each have a metal foil and an active material layer. The active material layers are arranged in such a manner that adjacent two of the active material layers face each other. Separators which are each interposed between the adjacent two of the active material layers. The separators are each a nonwoven fabric including fibers as protruding portions. The active material layers have a large number of active material particles which adhere to each other, and spaces formed between the active material particles, as fitting portions. The fibers are engaged with the spaces while the fibers enter the spaces.