Toyota Jidosha Kabushiki Kaisha

Tetsuya Kaneko

Kensaku Miyazawa

Yuya Ishihara

Shinichi Hamasaki

Masato Kamiya

Takayuki Hojo

Takanobu Yamada

Masaru Ishii

A method of evaluating a power storage device includes at least [a] to [f] below. [a] A power storage device is prepared. [b] A charge level of the power storage device is adjusted to produce a first potential difference between a positive electrode and a negative electrode. [c] The positive electrode or the negative electrode is selected as a reference electrode. [d] After the charge level is adjusted, an operation to insert a conductive rod-shaped member into a stack portion along a direction of stack of the positive electrode and the negative electrode is performed while a second potential difference between the reference electrode and the rod-shaped member is measured. [e] The rod-shaped member is stopped. [f] The power storage device is evaluated based on a state of the power storage device after the rod-shaped member is stopped.

Method of evaluating power storage device, method of manufacturing power storage device, and test system

A method of evaluating an all-solid-state battery includes preparing the all-solid-state battery. A charge level of the all-solid-state battery is adjusted to produce a first potential difference between a positive electrode and a negative electrode. The positive electrode or the negative electrode is selected as a reference electrode. After the charge level is adjusted, an operation to insert a conductive rod-shaped member into a stack portion along a direction of stack of the positive electrode and the negative electrode is performed while a second potential difference between the reference electrode and the rod-shaped member is measured. The rod-shaped member is stopped. The all-solid-state battery is evaluated based on a state of the all-solid-state battery after the rod-shaped member is stopped.

A nonaqueous electrolyte secondary battery includes a positive electrode including a positive electrode collector, a positive electrode active material layer on part of the surface of the positive electrode collector, and an insulating layer on another part of the surface of the positive electrode collector; a negative electrode including a negative electrode collector; and a negative electrode active material layer on part of the surface of the negative electrode collector; a separator that insulates the positive and negative electrodes; and a nonaqueous electrolyte. A width of the negative electrode active material layer is wider than the positive electrode active material layer. The insulating layer protrudes from the negative electrode active material layer; and exhibits a thermal shrinkage factor of 13% or less in a direction parallel to the surface of a square insulating layer sample having a side length of 5 cm and heated at 150° C. for 1 hour.

Nonaqueous electrolyte secondary battery

An object of the present invention is to provide a nonaqueous electrolyte secondary battery that allows more suitably suppressing short circuits between a positive electrode collector and a negative electrode active material layer, even when the battery generates heat. Provided is a nonaqueous electrolyte secondary batterythat includes a positive electrode and a negative electrode. The positive electrode includes a positive electrode collector, a positive electrode active material layer, and an insulating layer provided on another part of the surface of the positive electrode collector, so as to be adjacent to the positive electrode active material layer. The insulating layer contains an inorganic filler and a binder. A penetration strength of the insulating layer in a thickness direction perpendicular to the surface of the positive electrode collector is 0.05 N/mmor higher.

An object to provide a nonaqueous electrolyte secondary battery that allows more suitably suppressing short circuits between a positive electrode collector and a negative electrode active material layer, even when the battery generates heat. A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive electrode collector, a positive electrode active material layer, and an insulating layer provided on another part of the surface of the positive electrode collector, adjacent to the positive electrode active material layer. The insulating layer contains an inorganic filler and a binder; and is configure to exhibit a value of 13% or less of a thermal shrinkage factor in a direction parallel to the surface of an evaluation sample of an insulating layer formed to a square shape having a length of each side of 5 cm and heated at 150&#xb0; C. for 1 hour.

An assembled battery disclosed here includes a plurality of single cell array units each including single cells that are arranged in a lamination direction of a positive electrode and a negative electrode of an electrode body as an arrangement direction. The single cell array units are disposed parallel to each other such that arrangement directions of the single cells constituting the units are parallel to each other. Then, in the assembled battery, none of the single cells included in each of the single cell array units is directly electrically connected to adjacent single cells in the same unit, but is directly electrically connected to any one of the single cells constituting another single cell array unit through a bus bar.

Assembled battery

A battery pack includes a plurality of unit cells, each including an electrode body having a structure in which a positive electrode and a negative electrode are stacked, and a busbar that electrically connects a positive electrode terminal to a negative electrode terminal between the unit cells. The unit cells are stacked adjacent to one another in the same direction as a direction in which the positive electrode and the negative electrode of the electrode body are stacked. The busbar electrically connects the unit cells disposed apart from each other among the unit cells excluding the unit cells disposed adjacent to each other.

Battery pack

(a) A power storage device is prepared. (b) An evaluation jig is prepared. The evaluation jig includes an insulating tubular member and a conductive needle-shaped member. (c) A charge level of the power storage device is adjusted. (d) A positive electrode or a negative electrode is selected as a reference electrode. (e) An operation to insert the evaluation jig into the power storage device is performed. (f) The insertion operation is controlled to stop the tubular member when a tip end of the needle-shaped member comes in contact with an electrode different from the reference electrode. (g) Short-circuiting through the needle-shaped member is caused. (h) The power storage device is evaluated based on a state of the short-circuiting power storage device.

Method of evaluating power storage device, evaluation jig, and method of manufacturing power storage device

There is provided an assembled battery including a plurality of single cells and a plurality of bus bars connecting the plurality of single cells in series. The plurality of single cells is arranged such that a pair of flat side surfaces faces each other. The single cells each include a battery case, a positive electrode sheet, a negative electrode sheet, a positive electrode terminal, a negative electrode terminal, an electrical resistor disposed in a conductive path between the positive electrode sheet and the positive electrode terminal, and a pressure operative type current interruption mechanism disposed in a conductive path between the negative electrode sheet and the negative electrode terminal.

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Toyota, Japan

Tetsuya Kaneko