US-12626953-B2 - All solid state battery

US12626953B2US 12626953 B2US12626953 B2US 12626953B2US-12626953-B2

Abstract

An all solid state battery in which shift in positions of a plurality of a cell unit arranged along a thickness direction can be prevented is provided. The all solid state battery includes a plurality of the cell unit connected in series. The all solid state battery includes a cell unit A and a cell unit B, a second current collector AY in the cell unit A and a second current collector BX in the cell unit B are arranged to face each other interposing a first insulating portion, and a tab AX, a tab AY, and a tab B are fixed by a fixing member.

Inventors

Satomi Yamamoto
Keisuke Omori
Hajime Hasegawa

Assignees

TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date: 20260512
Application Date: 20230508
Priority Date: 20200131

Claims (1)

1 . An all solid state battery comprising a plurality of a cell unit arranged along a thickness direction and connected in series, the all solid state battery includes a cell unit A and a cell unit B as the cell unit, the cell unit A includes: a first current collector A, a first active material layer AX, a solid electrolyte layer AX, a second active material layer AX and a second current collector AX, arranged in order from a first surface side of the first current collector A, and a first active material layer AY, a solid electrolyte layer AY, a second active material layer AY and a second current collector AY, arranged in order from a second surface side opposite to the first surface side of the first current collector A, the cell unit B includes: a first current collector B, a first active material layer BX, a solid electrolyte layer BX, a second active material layer BX and a second current collector BX, arranged in order from a first surface side of the first current collector B, and a first active material layer BY, a solid electrolyte layer BY, a second active material layer BY and a second current collector BY, arranged in order from a second surface side opposite to the first surface side of the first current collector B, the second current collector AY in the cell unit A, and the second current collector BX in the cell unit B are arranged to face each other interposing a first insulating portion, the second current collector AX includes a tab AX at a position not overlapping the second active material layer AX in planar view, the second current collector AY includes a tab AY at a position not overlapping the second active material layer AY in planar view, the first current collector B includes a tab B at a position not overlapping the first active material layer BX and the first active material layer BY in planar view, the tab AX, the tab AY, and the tab B are fixed by a fixing member, the fixing member includes a first holding portion, a second holding portion, and a connecting portion connecting the first holding portion and the second holding portion, and the tab AX, the tab AY, and the tab B are sandwiched and fixed between the first holding portion and the second holding portion of the fixing member, the fixing member is elastic, the tab AX, the tab AY, and the tab B are pressurized in the thickness direction by sagging of the connecting portion, wherein a first distance is a distance between the first holding portion and the second holding portion in the thickness direction at an end of a connecting portion-side in a state the fixing member does not sandwich the tab AX, the tab AY, and the tab B, wherein the second distance is a distance between the first holding portion and the second holding portion in the thickness direction at a position located on an inner-side of the end of the connecting portion-side in the state the fixing member does not sandwich the tab AX, the tab AY, and the tab B, wherein the second distance is smaller than the first distance.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This nonprovisional application is a continuation application of U.S. patent application Ser. No. 17/156,031 filed Jan. 22, 2021, which claims priority to Japanese Patent Application No. 2020-015560 filed on Jan. 31, 2020, with the Japan Patent Office, the entire contents which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to an all solid state battery. BACKGROUND ART An all solid state battery is a battery including a solid electrolyte layer between a cathode active material layer and an anode active material layer, and one of the effects thereof is that the simplification of a safety device may be more easily achieved compared to a liquid-based battery including a liquid electrolyte containing a flammable organic solvent. Meanwhile, a battery (bipolar-type battery) including a bipolar electrode, in which a cathode active material layer is arranged on one surface of a current collector and an anode active material layer is arranged on the other side of the current collector, has been known. For example, Japanese Patent Application Laid-Open (JP-A) No. 2004-253155 discloses a bipolar-type battery wherein a part of surrounding portion of electrode is not subjected to an insulation treatment and a part of a current collector is exposed. In addition, it has been known that a plurality of current collector tabs are fixed by being pinched with clips. For example, Japanese Patent Application Laid-Open (JP-A) No. 2017-054704 discloses a battery comprising a clip for pinching a plurality of current collector tabs located in a belt-like electrode winded in a flat form. Japanese Patent Application Laid-Open (JP-A) No. 2012-069268 discloses an ultrasonic joining method of battery, the method comprising a step of pinching current collector tabs overlapped with a metal foil, with a clipping plate. Further, although it is a stacked-type battery wherein a plurality of unit cells are connected in parallel, Japanese Patent Application Laid-Open (JP-A) No. 2019-194946 discloses a stacked-type battery comprising a clip for holding a plurality of tabs in the stacked direction. Also, various techniques relating to current collector tabs have been known. For example, Japanese Patent Application Laid-Open (JP-A) No. 2018-018600 discloses a stacked battery comprising a conductive member between adjacent current collector tabs. Japanese Unexamined Patent Publication (JP-A) No. 2015-501064 discloses a cable-type secondary battery wherein a metal tab is a stainless-steel of which surface is processed with carbon, nickel, titanium, or silver. Further, Japanese Patent Application Laid-Open (JP-A) No. 2017-045594 discloses an all solid state battery wherein a calcium oxide layer is present on a surface of a tab portion. SUMMARY OF DISCLOSURE Technical Problem When the bipolar electrode, in which a cathode active material layer is arranged on one surface of a current collector and an anode active material layer is arranged on the other side of the current collector, is used, depending on conditions for pressing to densify each layer during production, difference in elasticity between the anode active material layer and the cathode active material layer may cause deformation of a current collector, which may generate a crack in the anode active material layer or the cathode active material layer. In particular, the generation of the crack is remarkable in an all solid state battery using an inorganic solid electrolyte since it has to be pressed with extremely high pressure during its production. In contrast, inventors of the present disclosure have obtained a knowledge that an all solid state battery, in which a crack is not easily generated in the anode active material layer or the cathode active material layer, can be obtained when the later described cell unit is used. Further, the inventors have obtained a knowledge that an all solid state battery wherein a plurality of the cell unit is connected in series can be obtained by preparing a plurality of the cell unit and stacking the cell unit interposing an insulating portion to electronically connect specified tabs. Meanwhile, when such an all solid state battery is produced, each cell unit may move to inner surface direction (orthogonal direction to the thickness direction) during being pressed (during pressing a plurality of the cell unit after arranging the cell unit along the thickness direction) and shift in positions of the cell unit tends to occur. The shift in positions of the cell unit can be a cause of short circuit. The present disclosure has been made in view of the above circumstances, and a main object thereof is to provide an all solid state battery in which the shift in positions of a plurality of the cell unit arranged along the thickness direction can be prevented. Solution to Problem In order to achieve the object, the present disclosure provides an all solid state battery comprising a plur