Electric storage device and rechargeable battery

Patent metadata

Field	Value
Publication number	US-9905826-B2
Application number	US-201314391201-A
Country	US
Kind code	B2
Filing date	Apr 11, 2013
Priority date	Apr 13, 2012
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

The electric storage device is provided with a case body and an electrode assembly accommodated in the case body. The electrode assembly includes positive and negative electrode sheets each having an active material layer. The case body includes at least one primary inner wall surface, at least one secondary inner wall surface, and corner surfaces. A plane that includes the boundary line between a primary inner wall surface and the corresponding corner surface and faces the corresponding secondary inner wall surface is defined as an imaginary boundary plane. An edge of the active material layer of a positive electrode sheet facing the corresponding secondary inner wall surface is positioned on the surface of the imaginary boundary plane, or is positioned in a region spaced further apart from the secondary inner wall surface facing the edge than the position of the imaginary boundary plane.

First claim

The invention claimed is:

1. An electric storage device comprising:
a case main body having a bottom wall, an opening portion located on the opposite side to the bottom wall, and a plurality of side walls extending from the bottom wall toward the opening portion;
an electrode assembly accommodated in the case main body and having a layer structure, in which at least one positive electrode sheet having an active material layer, at least one negative electrode sheet having an active material layer, and a separator located between the positive electrode sheet and the negative electrode sheet are laminated; and
a lid body closing the opening portion of the case main body, wherein
the case main body has at least one primary inner wall surface perpendicular to the laminating direction of the electrode assembly, at least one secondary inner wall surface adjoining the primary inner wall surface and being parallel with the laminating direction of the electrode assembly, and a corner surface connecting the mutually adjacent primary and secondary wall surfaces,
the separator includes a primary separator and a secondary separator sandwiching the positive electrode sheet,
the primary separator covers one surface of the corresponding positive electrode sheet and has a primary protruding portion protruding further outward than an edge of the active material layer of the positive electrode sheet,
the secondary separator covers the other surface of the positive electrode sheet and has a secondary protruding portion protruding in the same direction as the primary protruding portion, and
where a plane including a boundary line between the primary inner wall surface and the corner surface and facing the secondary inner wall surface is defined as an imaginary boundary plane, the primary and secondary protruding portions are joined at positions at each of which the distance between the secondary inner wall surface and the edge of the active material layer of the positive electrode sheet opposed to the secondary inner wall surface is not less than the length between the secondary inner wall surface and the imaginary boundary plane opposed to the secondary inner wall surface in a state where the primary separator and the secondary separator sandwich the positive electrode sheet therebetween,
the negative electrode sheet and the primary and secondary separators have the same measurement in a width direction, and
edges of the negative electrode sheet and edges of the primary and secondary separators are located in positions abutting the secondary inner wall surface.

2. An electric storage device comprising:
a case main body having a bottom wall, an opening portion located on the opposite side to the bottom wall, and a plurality of side walls extending from the bottom wall toward the opening portion;
an electrode assembly accommodated in the case main body and having a layer structure, in which at least one positive electrode sheet having an active material layer, at least one negative electrode sheet having an active material layer, and a separator located between the positive electrode sheet and the negative electrode sheet are laminated; and
a lid body closing the opening portion of the case main body, wherein
the case main body has at least one primary inner wall surface perpendicular to the laminating direction of the electrode assembly, at least one secondary inner wall surface adjoining the primary inner wall surface and being parallel with the laminating direction of the electrode assembly, and a corner surface connecting the mutually adjacent primary and secondary wall surfaces,
the separator includes a primary separator and a secondary separator sandwiching the positive electrode sheet,
the primary separator covers one surface of the corresponding positive electrode sheet and has a primary protruding portion protruding further outward than an edge of the active material layer of the positive electrode sheet,
the secondary separator covers the other surface of the positive electrode sheet and has a secondary protruding portion protruding in the same direction as the primary protruding portion, and
where a plane including a boundary line between the primary inner wall surface and the corner surface and facing the secondary inner wall surface is defined as an imaginary boundary plane, the primary and secondary protruding portions are joined at positions at each of which the distance between the secondary inner wall surface and the edge of the active material layer of the positive electrode sheet opposed to the secondary inner wall surface is not less than the length between the secondary inner wall surface and the imaginary boundary plane opposed to the secondary inner wall surface in a state where the primary separator and the secondary separator sandwich the positive electrode sheet therebetween, and
edges of the negative electrode sheet and edges of the primary and secondary separators are located at the same position, and
the edges of the negative electrode sheet and the edges of the primary and secondary separators are located in positions abutting the secondary inner wall surface.

3. The electric storage device according to claim 1 , wherein
the at least one secondary inner wall surface is one of two secondary inner wall surfaces, which are opposed to each other in a direction orthogonal to the laminating direction of the electrode assembly and parallel with the laminating direction of the electrode assembly,
the edge of the active material layer of the positive electrode sheet is one of a plurality of edges,
two of the edges are opposite from each other and each face one of the secondary inner wall surfaces,
the imaginary boundary plane is one of two imaginary boundary planes, each of which is opposed to one of the two secondary inner wall surfaces, and
each of the two edges is either located on the corresponding one of the two imaginary boundary planes or in an area more distant from the secondary inner wall surface to which the edge is opposed than the position of the corresponding imaginary boundary plane.

4. The electric storage device according to claim 1 , wherein
the primary separator and the secondary separator are each in the form of a rectangular sheet, and
the primary protruding portion and the secondary protruding portion protruding further outward than the edges opposite from each other in the active material layer of the positive electrode sheet are joined with each other.

5. The electric storage device according to claim 1 , wherein
the primary separator and the secondary separator are each in the form of a rectangular sheet, and
the primary protruding portion and the secondary protruding portion protruding further outward than the edges of the active material layer of the positive electrode sheet are joined with each other.

6. The electric storage device according to claim 1 , wherein
a collector tab electrically connected with an electrode terminal, which transfers electricity to and from the electrode assembly, is located at one of the edges of the active material layer of each positive electrode sheet,
the primary separator and the secondary separator are each in the form of a rectangular sheet, and
the primary protruding portion and the secondary protruding portion protruding further outward than the edges of the active material layer of the positive electrode sheet are joined with each other at a position where the protruding portions do not overlap with the collector tab.

7. The electric storage device according to claim 1 , wherein
the case main body is shaped as a rectangular box with a closed end and has four side walls extending from the opening portion toward the bottom wall,
adjacent side walls are connected with each other b

Assignees

• Toyota Jidoshokki Kk

Inventors

• Okuda Motoaki
• MINAGATA Atsushi
• Nishihara Hiroyasu

Classifications

• H01M10/0413 Primary

  Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes · CPC title

• H01M50/466

  U-shaped, bag-shaped or folded · CPC title

• H01M50/103

  prismatic or rectangular (H01M50/109, H01M50/11 take precedence) · CPC title

• H01M2/0237

  Electricity · mapped topic

• H01M2/18 Primary

  Electricity · mapped topic