CN112243548B

CN112243548B - Battery, battery pack, battery module, power storage device, vehicle, and flying object

Info

Publication number: CN112243548B
Application number: CN201880094366.6A
Authority: CN
Inventors: 岩村直树; 间明田博清; 山岸元气
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2018-09-21
Filing date: 2018-09-21
Publication date: 2023-03-21
Anticipated expiration: 2038-09-21
Also published as: WO2020059124A1; JP7024109B2; JPWO2020059124A1; CN112243548A

Abstract

The invention provides a thin battery, a battery pack, an electric storage device, a vehicle and a flying object, wherein the battery has excellent charge and discharge characteristics at a high rate. The battery of an embodiment includes: a flat electrode group (2) comprising a positive electrode (7), a positive electrode collector tab (7 a), a negative electrode (8), and a negative electrode collector tab (8 a); an electrode group-side positive electrode lead (12) electrically connected to the positive electrode collector tab (7 a); an electrode group-side negative electrode lead (14) electrically connected to a negative electrode collector tab (8 a); an outer packaging member (1) comprising a first outer packaging part (5) and a second outer packaging part (6); a positive electrode terminal part (3), wherein a positive electrode head part (17 a) protrudes to the outside of the first external packaging part (5), a positive electrode shaft part is inserted into a through hole of the positive electrode terminal lead (23), and the positive electrode shaft part is riveted and fixed on the first external packaging part (5) and the positive electrode terminal lead (23); and a negative electrode terminal portion (4), wherein a negative electrode head portion (32 a) protrudes outside the first exterior packaging portion (5), a negative electrode shaft portion is inserted into the through hole of the negative electrode terminal lead (36), and the negative electrode shaft portion is fixed to the first exterior packaging portion (5) and the negative electrode terminal lead (36) by caulking.

Description

Battery, battery pack, battery module, power storage device, vehicle, and flying object

Technical Field

Embodiments of the invention relate to a battery, a battery pack, a battery module, a power storage device, a vehicle, and a flight vehicle.

Background

A battery such as a primary battery or a secondary battery generally includes an electrode group having a positive electrode and a negative electrode, and an outer package member housing the electrode group.

Since the battery is thin, the lead wire in the battery is required to be compactly housed by being bent complicatedly, and the electrode terminal is no exception. Conventionally, the shaft portion of the electrode terminal has a circular shape with a perfect circle in cross section. However, since the battery is made thinner, the shaft diameter of the electrode terminal of the shaft portion having a circular cross section becomes smaller, and a large current is difficult to flow.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2017-010743

Disclosure of Invention

Technical problem to be solved by the invention

The present invention addresses the problem of providing a thin battery, a battery pack, a battery module, an electric storage device, a vehicle, and a vehicle, which have excellent charge/discharge characteristics at a high rate.

Means for solving the problems

The battery of an embodiment includes: the flat electrode group comprises a positive electrode, a positive electrode collector lug electrically connected with the positive electrode, a negative electrode and a negative electrode collector lug electrically connected with the negative electrode, wherein the positive electrode collector lug wound into a flat shape is positioned on the first end surface, and the negative electrode collector lug wound into a flat shape is positioned on the second end surface; an electrode group side positive electrode lead electrically connected with the positive electrode collector tab; an electrode group side negative electrode lead electrically connected to the negative electrode collector tab; an exterior member including a first exterior portion and a second exterior portion, the first exterior portion and the second exterior portion being welded to each other to form a space in which an electrode group is housed, and a positive terminal portion in which the first exterior portion has a through-hole on a positive collector tab side, the positive terminal portion including: a positive electrode external terminal including a positive electrode head portion and a positive electrode shaft portion extending from the positive electrode head portion; and a positive electrode terminal lead having a through hole, the positive electrode head portion protruding to the outside of the first external packaging portion, the positive electrode shaft portion being inserted into the through hole of the positive electrode terminal lead, the positive electrode shaft portion being caulked and fixed to the first external packaging portion and the positive electrode terminal lead; a negative electrode terminal portion in which a first exterior packaging portion has a through-hole on a negative electrode collector tab side, the negative electrode terminal portion including: a negative external terminal including a negative head portion and a negative shaft portion extending from the negative head portion; and a negative electrode terminal lead having a through-hole, wherein the negative electrode head portion protrudes to the outside of the first exterior covering portion, the negative electrode shaft portion is inserted into the through-hole of the negative electrode terminal lead, and the negative electrode shaft portion is fixed to the first exterior covering portion and the negative electrode terminal lead by caulking. The positive pole shaft part at least comprises a first positive pole shaft part of the elliptical truncated cone or the elliptical truncated cone and a second positive pole shaft part of the elliptical truncated cone. The first positive electrode shaft portion is disposed between the second positive electrode shaft portion and the positive electrode head portion. The top surface of the first positive electrode shaft portion is directly connected to the top surface of the second positive electrode shaft portion. The negative electrode shaft part at least comprises a first negative electrode shaft part of an elliptic truncated cone or an elliptic cylindrical frustum and a second negative electrode shaft part of the elliptic truncated cone. The first negative electrode shaft portion is disposed between the second negative electrode shaft portion and the negative electrode head portion. The top surface of the first negative electrode shaft portion is directly connected to the top surface of the second negative electrode shaft portion.

Drawings

Fig. 1 is a schematic perspective view of a battery according to a first embodiment.

Fig. 2 is an expanded perspective view of the battery shown in fig. 1, as viewed from the positive electrode side.

Fig. 3 is an expanded perspective view of the battery shown in fig. 1, as viewed from the negative side thereof.

Fig. 4 is a perspective view of an electrode assembly of the battery shown in fig. 1.

Fig. 5 is a perspective view showing a state in which the electrode group is partially developed.

Fig. 6 is a cross-sectional view of the positive electrode portion of fig. 1 taken along the longitudinal direction of the battery.

Fig. 7 is a cross-sectional view of the negative electrode portion of fig. 1 cut along the longitudinal direction of the battery.

Fig. 8 isbase:Sub>A cross-sectional view of the positive electrode portion of fig. 1 taken along the direction of planebase:Sub>A-base:Sub>A' of fig. 6.

Fig. 9 is a perspective view of the positive electrode external terminal (negative electrode external terminal) of the battery of the first embodiment.

Fig. 10 is a sectional view (a) in the short axis direction and a sectional view (b) in the long axis direction of the positive electrode external terminal (negative electrode external terminal) shown in fig. 9.

Fig. 11 (a), 11 (b), 11 (c), and 11 (d) are examples of the cross-sectional shape of the positive electrode external terminal (negative electrode external terminal).

Fig. 12 is a perspective view showing a structure in which a terminal portion is fixed to the first exterior packaging portion of the battery shown in fig. 1.

Fig. 13 (a) is a plan view of the second exterior packaging part, and fig. 13 (b) is a plan view of the first exterior packaging part.

Fig. 14 (a), 14 (b), 14 (c) and 14 (d) are three views showing the manufacturing process of the battery according to the first embodiment.

Fig. 15A is a process diagram showing an assembly process of a battery in which a plurality of electrode groups are housed.

Fig. 15B is a process diagram showing an assembly process of a battery in which a plurality of electrode groups are housed.

Fig. 15C is a process diagram showing an assembly process of a battery in which a plurality of electrode groups are housed.

Fig. 15D is a process diagram showing an assembly process of a battery in which a plurality of electrode groups are housed.

Fig. 16 is a cross-sectional view of the positive electrode portion in the modification of the first embodiment, taken along the longitudinal direction of the battery.

Fig. 17 is a cross-sectional view taken along the direction of the plane B-B' in fig. 16 in a modification of the first embodiment.

Fig. 18 is a perspective view of a positive electrode external terminal (negative electrode external terminal) of a battery in a modification of the first embodiment.

Fig. 19 is a sectional view (a) in the short axis direction and a sectional view (b) in the long axis direction of the positive electrode external terminal (negative electrode external terminal) shown in fig. 18.

Fig. 20 is a schematic perspective view of a battery according to a second embodiment.

Fig. 21 is an expanded perspective view of the battery shown in fig. 20.

Fig. 22 is an expanded perspective view of a portion of the battery shown in fig. 20.

Fig. 23 is a view showing that a terminal portion is fixed to the first exterior packaging portion of the battery shown in fig. 20.

Fig. 24 is a sectional view (a) of a part of the battery obtained when the battery is cut along the plane C-C 'of fig. 23, and a sectional view (b) of a part of the battery obtained when the battery is cut along the plane D-D'.

Fig. 25 is a perspective view of the positive electrode external terminal (negative electrode external terminal) of the battery of the second embodiment.

Fig. 26 is a sectional view (a) in the short axis direction and a sectional view (b) in the long axis direction of the positive electrode external terminal (negative electrode external terminal) shown in fig. 25.

Fig. 27 is a diagram showing a structure in which terminal portions are fixed to a first exterior portion of a battery according to a modification of the second embodiment.

Fig. 28 is a sectional view (a) of a part of the battery taken along the plane E-E 'of fig. 27 and a sectional view (b) of a part of the battery taken along the plane F-F'.

Fig. 29 is a perspective view of the positive electrode external terminal (negative electrode external terminal) of the battery in the modification of the second embodiment.

Fig. 30 is a sectional view (a) in the short axis direction and a sectional view (b) in the long axis direction of the positive electrode external terminal (negative electrode external terminal) shown in fig. 29.

Fig. 31 is a schematic diagram showing a first example of the assembled battery according to the third embodiment.

Fig. 32 is a schematic diagram showing a second example of the assembled battery according to the third embodiment.

Fig. 33 is an expanded perspective view of the battery module of the fourth embodiment.

Fig. 34 is a sectional view of a battery module of the fourth embodiment.

Fig. 35 is a schematic diagram of a power storage device according to a fifth embodiment.

Fig. 36 is a schematic diagram of a vehicle according to a sixth embodiment.

Fig. 37 is a schematic diagram of a flight object according to a seventh embodiment.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. In addition, the same reference numerals are given to the common components in the embodiments, and redundant description is omitted. The drawings are schematic views for facilitating description of the embodiments and understanding thereof, and the shapes, dimensions, ratios, and the like of the drawings are different from those of actual apparatuses, but they may be appropriately designed and changed by referring to the following description and known techniques.

[ first embodiment ]

A battery according to a first embodiment will be described with reference to fig. 1 to 15. Although some parts and parts of the drawings are not shown in the drawings, the positive electrode and the negative electrode are symmetrically configured, and therefore the part of one electrode not shown in the drawings is known from the structure of the other electrode. In the embodiment, it is recognized that the positive electrode and the negative electrode are configured asymmetrically.

The battery 100 shown in fig. 1 includes an outer package 1, an electrode group 2, a positive terminal portion 3, a negative terminal portion 4, and an electrolyte (not shown). The battery 100 shown in fig. 1 is, for example, a secondary battery. The battery 100 of the embodiment is thin. The thickness of the thin battery 100 (the minimum length of the external dimensions (height, width, depth) of the battery 100) is 5mm to 30 mm. Battery 100 is cup-shaped.

Fig. 2 is an expanded perspective view of the battery shown in fig. 1, as viewed from the positive electrode side. Fig. 3 is an expanded perspective view of the battery shown in fig. 1, as viewed from the negative side thereof. As shown in fig. 1,2, and 3, the outer jacket material 1 includes a first outer jacket portion 5 and a second outer jacket portion 6. The first external packaging member 5 is a bottomed rectangular tube container and has a flange portion 5b at an opening portion 5a. In the outer jacket material 1, the electrode group 2 is housed in a space formed by welding the flange portion 5b of the first outer jacket portion 5 and the second outer jacket portion 6.

The first exterior packaging part 5 and the second exterior packaging part 6 are preferably made of any one selected from the group consisting of stainless steel, aluminum laminate, and aluminum. In order to increase the battery capacity per unit volume of the battery 100, the thicknesses of the first exterior covering portion 5 and the second exterior covering portion 6, that is, the thicknesses of the first exterior covering portion 5 and the second exterior covering portion 6 are preferably set to be in the range of 0.02mm to 0.3 mm. By setting the range, contradictory properties such as mechanical strength and flexibility can be achieved at the same time. A more preferable range of the plate thickness is 0.05mm or more and 0.15mm or less.

As shown in fig. 1,2, and 3, a concave portion protruding inward is provided near the center of a corner portion connecting the short side wall and the bottom of the first external packaging member 5, and the bottom of the concave portion is an inclined surface 5d. The first external packaging member 5 has a depth equal to or less than the size of the opening 5a (the maximum length of the portion having the opening area). More preferably, the first external packaging material 5 has a depth (for example, as shown in fig. 2) equal to or less than the short side of the portion having the opening area. The first external packaging member 5 is a cup-shaped container having an opening 5a formed from a steel plate by, for example, shallow drawing. On the other hand, the second exterior packaging part 6 is a lid. The second exterior packaging member 6 covers the opening 5a of the first exterior packaging member 5. The second external packaging member 6 may be a cup-shaped container formed by shallow drawing, or may be a plate-shaped container, as in the first external packaging member 5. When the second exterior packaging member 6 is a cup-shaped container, the side surface of the second exterior packaging member 6 can be regarded as a part of the side surface of the first exterior packaging member 5. When the second external packaging member 6 is a cup-shaped container, the inner surface of the second external packaging member 6 on the side surface side can be regarded as a part of the inner surface of the first external packaging member 5. The electrode group 2 is housed in a space formed by welding the flange portion 5b of the first exterior case portion 5 to the four sides of the second exterior case portion 6. The welding is, for example, resistance seam welding. Resistance seam welding can achieve high airtightness and heat resistance at lower cost than laser welding.

Fig. 4 is a perspective view of the electrode group 2 of the battery 100 shown in fig. 1. The positive electrode collector tab 7a of the electrode group 2 shown in fig. 4 is electrically connected to the electrode group-side positive electrode lead 12. For example, when the U-shaped auxiliary positive electrode lead 11 is used, the auxiliary positive electrode lead 11 may sandwich the positive electrode current collector tab 7a and the auxiliary positive electrode lead 11 may be electrically connected to the electrode group side positive electrode lead 12. The positive electrode current collector tab 7a may be provided only at the center of the electrode group 2 by cutting away the portion of the positive electrode current collector tab 7a that does not contact the electrode group-side positive electrode lead 12 or the spare positive electrode lead 11.

Similarly, the negative electrode current collector tab 8a of the electrode group 2 shown in fig. 4 is electrically connected to the electrode group-side negative electrode lead 14. For example, when the U-shaped spare negative electrode lead 13 is used, the spare negative electrode lead 13 may be configured to electrically connect the electrode group-side negative electrode lead 14 and the negative electrode current collector tab 8a with the spare negative electrode lead 13 interposed therebetween. The negative electrode current collector tab 8a may be provided only at the central portion of the electrode group 2 by cutting away the portion of the negative electrode current collector tab 8a that does not contact the electrode group-side negative electrode lead 14 or the spare negative electrode lead 13.

Since the battery is thin, the space for accommodating the electrode group 2 is a low height space. The height of the space in which one electrode group 2 is housed is a value obtained by dividing the number of electrode groups 2 housed in the exterior member 1 and arranged in the height direction by the distance from the bottom of the first exterior case portion 5 to the second exterior case portion 6. Since the battery is thin, the height of the space for accommodating each electrode group 2 is 5mm to 30 mm. Since the space for housing the electrode group 2 is a space having a small height, the shape of the lead is limited.

Fig. 5 is a perspective view showing a state in which the electrode group 2 is partially developed. As shown in fig. 5, the electrode group 2 has a flat shape and includes a positive electrode 7, a negative electrode 8, and a separator 9 disposed between the positive electrode 7 and the negative electrode 8. The flat electrode group 2 includes a positive electrode 7, a positive electrode collector tab 7a electrically connected to the positive electrode 7, a negative electrode 8, and a negative electrode collector tab 8a electrically connected to the negative electrode 8, and the positive electrode collector tab 7a wound in a flat shape is located on a first end surface, and the negative electrode collector tab 8a wound in a flat shape is located on a second end surface. One of the 2 flat surfaces of the electrode group 2 faces the bottom surface 5c of the first external packaging member 5, and the other of the 2 flat surfaces of the electrode group 2 faces the surface of the second external packaging member 6.

The electrode group 2 is housed in the first exterior packaging part 5 such that the first end surface 7a faces the positive terminal part 3 and the second end surface 8a faces the negative terminal part 4. Therefore, the plane intersecting the first end face 7a and the second end face 8a of the electrode group 2 faces the bottom face 5c in the first external packaging member 5, and the curved face intersecting the first end face 7a and the second end face 8a faces the long-side face in the first external packaging member 5.

The positive electrode 7 includes: a strip-shaped positive electrode current collector made of, for example, foil, a positive electrode current collector tab 7a made of one end portion parallel to the long side of the positive electrode current collector, and a positive electrode material layer (positive electrode active material-containing layer) 7b formed on the positive electrode current collector except at least a portion of the positive electrode current collector tab 7 a.

On the other hand, the negative electrode 8 includes: a strip-shaped negative electrode current collector made of, for example, foil, a negative electrode current collector tab 8a made of one end portion parallel to the long side of the negative electrode current collector, and a negative electrode material layer (negative electrode active material-containing layer) 8b formed on the negative electrode current collector except at least a portion of the negative electrode current collector tab 8a. The electrode group 2 is formed by winding the positive electrode 7, the separator 9, and the negative electrode 8 in a flat shape such that the positive electrode material layer 7b of the positive electrode 7 and the negative electrode material layer 8b of the negative electrode 8 face each other with the separator 9 interposed therebetween, the positive electrode collector tab 7a protrudes toward one side of the winding shaft from the negative electrode 8 and the separator 9, and the negative electrode collector tab 8a protrudes toward the other side from the positive electrode 7 and the separator 9. Therefore, in the electrode group 2, the positive electrode current collector tab 7a wound in a flat spiral shape is positioned on the first end surface perpendicular to the winding axis.

Further, a negative electrode current collector tab 8a wound flat and spirally is positioned on a second end surface perpendicular to the winding axis. The electrode group 2 holds an electrolyte (not shown). The insulating sheet 10 covers a portion between the positive electrode current collector tab 7a and the negative electrode current collector tab 8a in the outermost periphery of the electrode group 2. The insulating sheet 10 covers the outermost periphery of the electrode group 2 except for the positive electrode current collector tab 7a and the negative electrode current collector tab 8a. The electrode group 2 holds an electrolyte (not shown).

Fig. 6 is a cross-sectional view of the positive electrode 7 shown in fig. 1, taken along the longitudinal direction of the battery. Fig. 7 is a cross-sectional view of the negative electrode 8 shown in fig. 1, taken along the longitudinal direction of the battery. Fig. 6 of the positive terminal side and fig. 7 of the negative terminal side are symmetrical. In FIG. 6, the virtual line (dashed line) of A-A' is shown.

Fig. 8 isbase:Sub>A cross-sectional view taken along the planebase:Sub>A-base:Sub>A' on the positive electrode 7 side of fig. 6. thebase:Sub>A-base:Sub>A' surface isbase:Sub>A cross section passing through the center of the positive electrode terminal 17 (the center of the inclined surface 5 d). Fig. 8 isbase:Sub>A cross-sectional view of thebase:Sub>A-base:Sub>A' plane, that is,base:Sub>A cross-sectional view taken along the depth direction of battery 100 (in the direction from positive terminal 17 toward negative terminal) from the virtual line. Since the positive electrode 7 side and the negative electrode 8 side are symmetrical,base:Sub>A cross-sectional view of thebase:Sub>A-base:Sub>A' plane on the negative electrode 8 side is not shown, but the structure on the negative electrode 8 side can be understood by referring to the drawing on the positive electrode 7 side.

As shown in fig. 2, 3, 6, and 8, the positive terminal portion 3 includes a through hole 15 that opens on the inclined surface 5d of the first exterior covering portion 5, a positive electrode external terminal 17, a positive electrode insulating member 18a, a positive electrode reinforcing member (annular member) 18b, an insulating gasket 19, and a positive electrode terminal insulating member 20.

The first exterior packaging part 5 has a through-hole 15 on the positive electrode collector tab side in the positive terminal part 3. The positive electrode external terminal 17 of the positive electrode terminal portion 3 includes a positive electrode head portion 17a and a positive electrode shaft portion extending from the positive electrode head portion 17 a. The positive terminal portion 3 includes a positive terminal lead 23 having a through hole 23a. In the positive terminal portion 3, the positive head portion 17a protrudes outside the first exterior cover 5, the positive shaft portion is inserted into the through hole 23a of the positive terminal lead 23, and the positive shaft portion is swaged and fixed to the first exterior cover 5 and the positive terminal lead 23.

As shown in fig. 5, a flange portion (annular rising portion) 16 extends from the peripheral edge portion of the through hole 15 toward the inside of the outer jacket material 1, and the flange portion 16 is formed by flanging.

Fig. 9 shows a perspective view of the positive electrode external terminal 17. As shown in fig. 6, 8, and 9, the positive electrode external terminal 17 includes, for example, a truncated pyramid-shaped positive electrode head portion 17a and a positive electrode shaft portion penetrating the through hole 15 of the first external packaging member 5. The positive electrode shaft portion is parallel to the top surface of the positive electrode head portion 17a, and protrudes from the plane on the side opposite to the top surface. The positive electrode external terminal 17 is formed of a conductive material such as aluminum or an aluminum alloy.

The positive electrode shaft portion includes at least a first positive electrode shaft portion 17b of an elliptical truncated cone or an elliptical cylindrical truncated cone and a second positive electrode shaft portion 17c of an elliptical truncated cone. In the perspective view of the positive electrode external terminal 17 shown in fig. 9, the first positive electrode shaft portion 17b has an elliptical truncated cone shape. A modified example will be described in which the first positive electrode shaft portion 17b is an elliptical cylindrical table. The first positive electrode shaft 17b is disposed between the second positive electrode shaft 17c and the positive electrode head 17 a. By making the cross section of the positive electrode shaft portion elliptical, the limitation of the shape and volume of the electrode terminal portion can be satisfied, and the contact surface between the positive electrode shaft portion and the positive electrode terminal lead 23 and the cross section of the positive electrode shaft portion can be increased as compared with the case where the cross section of the positive electrode shaft portion is circular. By forming the second positive electrode shaft portion 17c to have an elliptical truncated cone shape, the cross-sectional area of the second positive electrode shaft portion 17c can be increased, and the caulking fixation to the positive electrode terminal lead 23 can be made stronger.

As shown in fig. 6 and 8, the cross section of the positive electrode shaft (the cross section of the positive electrode shaft in the direction perpendicular to the direction in which the positive electrode shaft is connected to the positive electrode head 17 a) is the smallest in the electrical path between the positive electrode collector tab 7a and the positive electrode external terminal 17. If the cross section of the positive electrode shaft portion is made larger than the positive electrode head portion 17a, the positive electrode external terminal 17 cannot be inserted through the through hole 15. In order to charge and discharge the battery 100 at a high rate, it is preferable to increase the cross-sectional area of the electrical path between the positive electrode current collector tab 7a and the positive electrode external terminal 17. When the positive electrode external terminal 17 is fixed by caulking, the cross-sectional area of the positive electrode shaft portion is the smallest. That is, in the terminal portion of the battery, if the sectional area of the positive electrode shaft portion is increased, the battery 100 can be charged and discharged at a higher rate. However, if the cross-sectional area of the positive electrode shaft portion is simply increased, the thickness of the battery 100 (the thickness of the battery 100 with respect to the battery capacity) increases, or the battery capacity decreases. Therefore, in the embodiment, the cross-sectional area of the positive electrode shaft portion is made elliptical, so that the cross-sectional area of the positive electrode shaft portion can be increased without adversely affecting the thickness of the battery 100 and the battery capacity. The internal shape of the battery 100 including the positive electrode external terminal 17 is determined from a cross section obtained by performing a CT (Computed Tomography) inspection using X-rays.

The first positive electrode shaft portion 17b and the second positive electrode shaft portion 17c have top and bottom surfaces. The tip end surface of the smaller elliptical truncated cone is used as the top surface, and the tip end surface of the larger elliptical truncated cone is used as the bottom surface. The bottom surface of the first positive electrode shaft portion 17b is a surface facing the positive electrode head portion 17 a. The top surface of the first positive electrode shaft portion 17b is the surface opposite to the bottom surface of the first positive electrode shaft portion 17 b. The top surface of the first positive electrode shaft portion 17b faces the top surface of the second positive electrode shaft portion 17c. The top surface of the second positive electrode shaft portion 17c is a surface facing the positive electrode head portion 17 a. The bottom surface of the second positive electrode shaft portion 17c is the surface on the opposite side of the top surface of the second positive electrode shaft portion 17c. The side surface of the first positive electrode shaft portion 17b faces the insulating spacer 19, more specifically, the flange portion 19a. The top surface of the first positive electrode shaft portion 17b is directly connected to the top surface of the second positive electrode shaft portion 17c. Between the first positive electrode shaft portion 17b and the positive electrode head portion 17a, an elliptical truncated cone or an elliptical truncated cylinder, not shown, may be further provided. From the viewpoint of high-rate charge and discharge, it is preferable that the cross-sectional area of the elliptic truncated cone or elliptic cylindrical truncated cone, not shown, between the first positive electrode shaft portion 17b and the positive electrode head portion 17a is equal to or smaller than the cross-sectional area of the positive electrode head portion 17a, larger than the cross-sectional area of the first positive electrode shaft portion 17b, and larger than the cross-sectional area of the second positive electrode shaft portion 17c. The positive electrode shaft portion is preferably elliptical in cross section, and the positive electrode external terminal 17 is less likely to rotate.

Fig. 10 shows a cross-sectional view in the short axis direction (fig. 10 (a)) and a cross-sectional view in the long axis direction (fig. 10 (b)) of the positive electrode external terminal 17. The short axis direction of the positive electrode external terminal 17 (the short axis direction of the first positive electrode shaft 17b and the short axis direction of the second positive electrode shaft 17 c) is a direction of a cross section passing through the center of the positive electrode shaft and having the thinnest axial diameter of the positive electrode shaft. The longitudinal direction of the positive electrode external terminal 17 (the longitudinal direction of the first positive electrode shaft 17b and the longitudinal direction of the second positive electrode shaft 17 c) is a direction of a cross section passing through the center of the positive electrode shaft and having the maximum axial diameter of the positive electrode shaft. The short axis direction of the first positive electrode shaft 17b is preferably the same direction as the short axis direction of the second positive electrode shaft 17c. The longitudinal direction of the first positive electrode shaft 17b is preferably the same as the longitudinal direction of the second positive electrode shaft 17c. The short axis direction of the positive electrode external terminal 17 (the short axis direction of the first positive electrode shaft 17b and the short axis direction of the second positive electrode shaft 17 c) is the short side direction of the plane on the positive electrode shaft side of the positive electrode head 17a, and the long axis direction of the positive electrode external terminal 17 (the long axis direction of the first positive electrode shaft 17b and the long axis direction of the second positive electrode shaft 17 c) is the longitudinal direction of the plane on the positive electrode shaft side of the positive electrode head 17 a. The short axis direction of the positive electrode external terminal 17 (the short axis direction of the first positive electrode shaft 17b and the short axis direction of the second positive electrode shaft 17 c) and the long axis direction of the positive electrode external terminal 17 (the long axis direction of the first positive electrode shaft 17b and the long axis direction of the second positive electrode shaft 17 c) are preferably parallel or substantially parallel (within ± 3 degrees of the angular difference) to the inclined surface 5d.

As shown in fig. 10, the length of the short axis of the top surface of the first positive electrode shaft portion 17b is defined as Aa1, and the length of the long axis of the top surface of the first positive electrode shaft portion 17b is defined as Aa2. The length of the short axis of the bottom surface of first positive electrode shaft 17b is Ab1, and the length of the long axis of the bottom surface of first positive electrode shaft 17b is Ab2. The length of the minor axis of the top surface of the second positive electrode shaft 17c is Ba1, and the length of the major axis of the top surface of the second positive electrode shaft 17c is Ba2. The length of the minor axis of the bottom surface of the second positive electrode shaft 17c is Bb1, and the length of the major axis of the bottom surface of the second positive electrode shaft 17c is Bb2.

Aa1 and Ab1 satisfy Aa1< Ab1 (Aa 1 ≦ Ab1 if the first positive electrode shaft portion 17b is an elliptical column modified example is included). Aa2 and Ab2 satisfy Aa2 < Ab2 (Aa 2 ≦ Ab2 if the first positive electrode shaft portion 17b is an elliptical column modified example is included). Ba1 and Bb1 satisfy Ba 1< Bb1.Ba2 and Bb2 satisfy Ba2 < Bb2.

In addition, aa1, aa2, ba1, ba2, bb1 and Bb2 preferably satisfy | (Aa 1-Ba 1) - (Aa 2-Ba 2) | ≦ 0.1mm and (Bb 2-Ba 2) < (Bb 1-Ba 1). If | (Aa 1-Ba 1) - (Aa 2-Ba 2) | ≦ 0.1mm, there is an advantage that the first positive electrode shaft portion 17b and the positive electrode terminal lead 23 can be stably brought into contact. If (Bb 2-Ba 2) < (Bb 1-Ba 1) is satisfied, there is an advantage that the area of the contact portion between the second positive electrode shaft portion 17c and the positive electrode terminal lead 23 can be increased and the caulking portion can be made strong. From this viewpoint, it is more preferable that 1.2 (Bb 2-Ba 2) < (Bb 1-Ba 1) be satisfied.

It is preferable that the length of the minor axis of the top surface of the first positive electrode shaft 17b, i.e., aa1, and the length of the major axis of the top surface of the first positive electrode shaft 17b, i.e., aa2, satisfy 1.1. Ltoreq. Aa2/Aa 1. Ltoreq.2.0. When Aa2/Aa1 is less than 1.1, the cross-sectional shape of the first positive electrode shaft portion 17b is close to a circle, and when Aa2/Aa1 is greater than 2.0, the long axis is too long, thereby reducing the cross-sectional area. Therefore, the above range is preferably satisfied from the viewpoint of charge and discharge at a high rate.

The length Ab1, which is the length of the short axis of the bottom surface of the first positive electrode shaft 17b, and Ab2, which is the length of the long axis of the bottom surface of the first positive electrode shaft 17b, preferably satisfy 1.08 ≦ Ab2/Ab1 ≦ 2.0. When Ab2/Ab1 is less than 1.08, the cross-sectional shape of the first positive electrode shaft portion 17b is close to a circle, and when Ab2/Ab1 is greater than 2.0, the long axis is long, and the cross-sectional area is thereby reduced. Therefore, the above range is preferably satisfied from the viewpoint of charge and discharge at a high rate.

Further, if the length of the long axis of the top surface of the first positive electrode shaft portion 17b, i.e., aa2, and the length of the long axis of the top surface of the second positive electrode shaft portion 17c, i.e., ba2, satisfy 1.05 ≦ Aa2/Ba2 ≦ 1.5, there are the following advantages: the first positive electrode shaft portion 17b can be stably brought into contact with the positive electrode terminal lead 23. When Aa2/Ba2 is less than 1.05, it is not preferable from the viewpoint of the assemblability of the positive electrode terminal lead 23. When Aa2/Ba2 is larger than 1.5, the sectional area becomes small when Ba2 is small, which is not preferable from the viewpoint of high-rate charge and discharge, and when Aa2 is large, the sealing portion formed by the insulating gasket 19 increases, which is not preferable from the viewpoint of airtightness.

Fig. 11 shows an example of a sectional shape of the shaft portion of the positive electrode external terminal 17. The ellipse in the embodiment is not limited to the mathematically defined ellipse and is broadly explained. A part of an example of an elliptical shape that is broadly explained is shown in fig. 11. Fig. 11 (a) is a mathematically defined ellipse. Fig. 11 (b) is an elliptical shape of a judgelet (a kind of gold coin in the time of jianghu). Fig. 11 (c) is a racetrack shape, which is also included in the oval shape. Fig. 11 (d) shows a shape in which the corners of a diamond are rounded (for example, TO-3 type of bipolar transistor), which is also included in an elliptical shape. The elliptical shape of the shaft portion of the negative external terminal 32 is also the same as that of the shaft portion of the positive external terminal 17. In addition, the elliptical shape in the embodiment is a shape that does not include significant corners.

In addition, the positive electrode shaft portion is preferably solid from the viewpoint of performing charge and discharge at a high rate. Solid means that the positive electrode shaft portion has substantially no void and is substantially made of metal or alloy. More preferably, the positive electrode external terminal 17 is solid as a whole.

The positive electrode insulating member 18a has a through hole and a projection, and insulates the first external packaging part 5 from the positive electrode external terminal 17 and the positive electrode terminal lead 23. The positive electrode insulating member 18a is an annular member having a convex portion. The convex portion of the positive electrode insulating member 18a extends in a direction opposite to the direction in which the positive electrode terminal lead 23 exists. The positive electrode insulating member 18a is an insulating member.

The positive electrode insulating member 18a having the convex portion is preferably made of at least 1 kind of resin material selected from the group consisting of a fluororesin, a fluororubber, a polyphenylene sulfide resin (PPS resin), a polyether ether ketone resin (PEEK resin), a polypropylene resin (PP resin), a polybutylene terephthalate resin (PBT resin), and the like, for example.

The positive electrode reinforcing member 18b is formed of, for example, a circular ring having a through hole and formed of a material having higher rigidity than the gasket. The positive electrode reinforcing member 18b is disposed between the first exterior cover 5 and the positive electrode insulating member 18a. Examples of the material having higher rigidity than the gasket include stainless steel, a material plated with iron (e.g., ni, niCr, etc.), ceramics, and a resin capable of having higher rigidity than the gasket (e.g., polyphenylene sulfide (PPS), polybutylene terephthalate (PBT)). As shown in fig. 6, the positive electrode reinforcing member 18b is disposed on the outer peripheral surface of the burring 16 and is in contact with the burring 16 and the positive electrode insulating member 18a. Since the outer jacket material 1 is thin, the first outer jacket 5 and the turned-over portion 16 are preferably reinforced by the positive electrode reinforcing member 18b.

The positive electrode external terminal 17 is inserted into the through hole of the positive electrode insulating member 18a and the through hole of the positive electrode reinforcing member 18b. The positive electrode reinforcing member 18b is sandwiched between the convex portion of the positive electrode insulating member 18a and the flanged portion 16 of the first exterior covering 5. Even if the positive electrode terminal lead 23 partially moves, the positive electrode terminal lead 23 is more reliably prevented from being short-circuited with the first external packaging part 5 by the positive electrode insulating member 18a, which is preferable in this regard. Further, the reliability of insulation between the positive electrode terminal lead 23 and the first external packaging member 5 is preferably improved by the convex portion of the positive electrode insulating member 18a.

As shown in fig. 2 and 6, the insulating spacer 19 is a cylindrical body (cylindrical portion) having a flange 19a at one open end. As shown in fig. 2 and 6, the insulating spacer 19 has a cylindrical body part inserted into the through hole 15 and the burring 16, and a flange part 19a disposed on the outer periphery of the through hole 15 on the outer surface of the first exterior cladding 5. The insulating spacer 19 is made of a resin such as a fluororesin, a fluororubber, a polyphenylene sulfide resin (PPS resin), a polyether ether ketone resin (PEEK resin), a polypropylene resin (PP resin), and a polybutylene terephthalate resin (PBT resin).

As shown in fig. 2 and 6, the positive electrode terminal insulating member 20 is a plate-like member bent at an obtuse angle, and has a through hole 20a at the bottom. The positive terminal insulating member 20 is disposed on the outer surface of the first exterior package 5. The flange 19a of the insulating spacer 19 is inserted into the through hole 20a of the positive electrode terminal insulating member 20.

The positive terminal portion 3 further includes a positive terminal lead 23. The positive electrode terminal lead 23 is a conductive plate having a through hole 23a and a first extending portion 23b extending toward the opening of the first exterior covering 5, i.e., toward the second exterior covering 6. In fig. 5, the positive electrode terminal lead 23 has a first extension portion 23a extending toward the electrode group 2 side. The first extended portion 23b of the positive electrode terminal lead 23 is integrated with the first extended portion 12a of the electrode group-side positive electrode lead 12 by welding. The facing surfaces of the first extending portion 23b and the first extending portion 12a are welded, and further, the end surface of the first extending portion 23b on the tip side and the end surface of the first extending portion 12a are also welded. At least the first extending portion 23b of the positive electrode terminal lead 23 and the first extending portion 12a of the electrode group-side positive electrode lead 12 are perpendicular or substantially perpendicular (80 ° or more and 100 ° or less) to the surface of the second exterior cover 6. The first extending portion 23b of the positive electrode terminal lead 23 and at least the tip portion of the first extending portion 12a of the electrode group-side positive electrode lead 12 are perpendicular or substantially perpendicular to the surface of the second exterior cover 6, and are manufactured without bending the leads after the first extending portion 23b of the positive electrode terminal lead 23 and the first extending portion 12a of the electrode group-side positive electrode lead 12 are welded. The lead is bent after welding, which has an advantage that the wiring at the terminal portion of the electrode can be made compact, but the lead is required to be thin in thickness in order to be bent with high accuracy after welding. However, it is not preferable to reduce the thickness of the lead because it is difficult to flow a large current. By orienting the welded portion in the direction of the surface of the second exterior package 6, the thickness of the lead can be increased. The shapes of the electrode group-side positive electrode lead 12 and the positive electrode terminal lead 23, including the bent shape of the lead, are not limited to the shapes shown in fig. 6, and may be other shapes.

In view of the large current characteristics, the thickness of the positive electrode terminal lead 23 may be 0.5mm or more and 3.0mm or less, and the thickness of the electrode group-side positive electrode lead 12 may be 0.5mm or more and 3.0mm or less. Further, in consideration of the lead bending step before welding the leads to each other and the large current characteristic, the sum of the thickness of the positive electrode terminal lead 23 and the thickness of the electrode group-side positive electrode lead 12 is preferably 1.0mm or more and 1.2mm or less. These thicknesses are preferably satisfied at least in the welded portion.

The battery 100 is further provided with a first positive electrode insulation reinforcing member 24. The first positive electrode insulation reinforcing member 24 is disposed on the inner surface side of the first exterior packaging part 5. More specifically, the first positive electrode insulation reinforcing member 24 is disposed on the inner surface side of the first exterior cover 5 between the positive electrode terminal lead 23 and the first exterior cover 5. As shown in fig. 2 and 6, the first positive electrode insulation reinforcing member 24 includes: a main body portion 24a having a structure in which a bottomed rectangular cylinder is half-divided in a longitudinal direction; a circular groove 24b formed in the body portion 24a; and a through hole 24c opening in the center of the circular groove 24 b. The positive electrode insulating member 18a, the positive electrode reinforcing member 18b, and the positive electrode external terminal 17 are disposed in the through hole 24c. The main body portion 24a of the first positive electrode terminal insulating and reinforcing member 24 covers the corner portion of the first external packaging part 5 connected from the short-side wall to the bottom surface and the corner portion of the first external packaging part 5 connected from the short-side wall to the long-side surface. This can reinforce the first external packaging member 5, particularly, the vicinity of the corner where the short-side wall and the long-side wall intersect with the bottom. The positive electrode insulating member 18a disposed on the outer peripheral surface of the burring 16 is disposed in the circular groove 24 b. The through hole 24c communicates with the opening of the cuff 16 and the through hole 15 of the first exterior package portion 5. The positive terminal lead 23 is disposed on the first positive terminal insulation reinforcing member 24. The through hole 23a of the positive electrode terminal lead 23 communicates with the through hole 24c of the first positive electrode terminal insulation reinforcing member 24, the opening of the burring 16, and the through hole 15 of the first exterior cladding 5.

The second positive electrode insulation reinforcing member 25, which is a pair of the first positive electrode insulation reinforcing member 24, is disposed on the inner surface side of the first exterior cover 5 and the inner surface side of the second exterior cover 6. As shown in fig. 2, the second positive electrode insulation reinforcing member 25 has a structure in which a bottomed rectangular tube is half-divided in the longitudinal direction. One first positive electrode insulating and reinforcing member 24 covers approximately half of the positive electrode collector tab 7a from the winding center to the first exterior covering portion 5 side. The other second positive electrode insulation reinforcing member 25 covers about half of the positive electrode collector tab 7a from the winding center to the second exterior covering portion 6 side. This can reinforce the second exterior cover 6, particularly in the vicinity of the short side.

After the shaft portion of the positive electrode external terminal 17 is inserted into the insulating spacer 19, the through hole 20a of the positive electrode terminal insulating member 20, the through hole 15 of the first external packaging member 5, the through hole 24c of the positive electrode terminal insulating reinforcing member 24, and the through hole 23a of the positive electrode terminal lead 23, plastic deformation occurs by caulking. As a result, these components are integrated, and the positive electrode external terminal 17 is electrically connected to the positive electrode terminal lead 23. Therefore, the positive electrode external terminal 17 also functions as a rivet. Further, the second positive electrode shaft portion 17c and the positive electrode terminal lead 23 may be fixed by caulking, and at least a part or all of the inner wall of the through hole 23a of the positive electrode terminal lead 23 may be welded to the second positive electrode shaft portion 17c, thereby achieving a stronger connection and an improvement in electrical conductivity.

As shown in fig. 3 and 7, the negative terminal portion 4 includes a through hole 30 opened on the inclined surface 5d of the first exterior covering 5, a negative external terminal 32, a negative insulating member 33a, a negative reinforcing member (annular member) 33b, an insulating spacer 34, and a negative terminal insulating member 35.

In the negative terminal portion 4, the first exterior covering portion 5 has a through-hole 30 on the negative electrode current collector tab 8a side. The negative external terminal 32 of the negative terminal portion 4 includes a negative head portion 32a and a negative shaft portion extending from the negative head portion 32 a. The negative terminal portion 4 includes a negative terminal lead 36 having a through hole 36 a. In the negative terminal portion 4, the negative head portion 32a protrudes outside the first exterior covering portion 5, the negative shaft portion is inserted into the through hole 36a of the negative terminal lead 36, and the negative shaft portion is fixed to the first exterior covering portion 5 and the negative terminal lead 36 by caulking.

Fig. 9 shows a perspective view of the negative external terminal 32. As shown in fig. 7 and 9, the negative electrode external terminal 32 includes, for example, a truncated pyramid-shaped negative electrode head portion 32a and a negative electrode shaft portion. The negative electrode shaft portion protrudes from a plane parallel to the top surface of the negative electrode head portion 32 a. The negative electrode external terminal 32 is formed of a conductive material such as aluminum or an aluminum alloy.

The negative electrode shaft portion includes at least a first negative electrode shaft portion 32b of an elliptical truncated cone or an elliptical cylindrical truncated cone and a second negative electrode shaft portion 32c of an elliptical truncated cone. In the perspective view of the negative electrode external terminal 32 shown in fig. 9, the first negative electrode shaft portion 32b has an elliptical truncated cone shape. A modified example will be described in which the first negative electrode shaft portion 32b is an elliptical cylindrical table. The first negative electrode shaft portion 32b is disposed between the second negative electrode shaft portion 32c and the negative electrode head portion 32 a. By making the cross section of the negative electrode shaft portion elliptical, the limitation of the shape and volume of the electrode terminal portion can be satisfied, and the contact surface of the negative electrode shaft portion with the negative electrode terminal lead 36 and the cross-sectional area of the negative electrode shaft portion can be increased as compared with the case where the cross section of the negative electrode shaft portion is circular. By making the second negative electrode shaft portion 32c an elliptical truncated cone, the cross-sectional area of the second negative electrode shaft portion 32c can be increased, and the caulking fixation to the negative electrode terminal lead 36 can be made stronger.

As shown in fig. 7 and fig. 8 as a reference, the cross section of the negative electrode shaft portion (the cross section of the negative electrode shaft portion in the direction perpendicular to the direction in which the negative electrode shaft portion and the negative electrode head portion 32a are connected) is smallest in the electrical path between the negative electrode collector tab 8a and the negative electrode external terminal 32. If the negative electrode shaft portion is made larger in cross section than the negative electrode head portion 32a, the negative electrode external terminal 32 cannot be inserted through the through hole 15. In order to charge and discharge the battery 100 at a high rate, it is preferable to increase the cross-sectional area of the electrical path between the negative electrode current collector tab 8a and the negative electrode external terminal 32. When the negative electrode external terminal 32 is crimped and fixed, the cross-sectional area of the negative electrode shaft portion is minimized. That is, in the terminal portion of the battery, if the cross-sectional area of the negative electrode shaft portion is increased, the battery 100 can be charged and discharged at a higher rate. However, if the cross-sectional area of the negative electrode shaft portion is simply increased, the thickness of the battery 100 (the thickness of the battery 100 with respect to the battery capacity) increases, or the battery capacity decreases. Therefore, in the embodiment, the cross-sectional area of the negative electrode shaft portion is made elliptical, so that the cross-sectional area of the negative electrode shaft portion can be increased without adversely affecting the thickness and the battery capacity of the battery 100.

The first negative electrode shaft portion 32b and the second negative electrode shaft portion 32c have top and bottom surfaces. The tip end surface of the smaller elliptical frustum is used as the top surface, and the tip end surface of the larger elliptical frustum is used as the bottom surface. The bottom surface of the first negative electrode shaft portion 32b faces the negative electrode head portion 32 a. The top surface of the first negative electrode shaft portion 32b is the surface opposite to the bottom surface of the first negative electrode shaft portion 32 b. The top surface of the first negative electrode shaft portion 32b faces the top surface of the second negative electrode shaft portion 32c. The top surface of the second negative electrode shaft portion 32c faces the negative electrode head portion 32 a. The bottom surface of the second negative electrode shaft portion 32c is the surface opposite to the top surface of the second negative electrode shaft portion 32c. The side surface of the first negative electrode shaft portion 32b faces the insulating gasket 34, more specifically, the flange portion 34a. The top surface of the first negative electrode shaft portion 32b is directly connected to the top surface of the second negative electrode shaft portion 32c. Between the first negative electrode shaft portion 32b and the negative electrode head portion 32a, an elliptical truncated cone or an elliptical truncated cylinder, not shown, may be further provided. From the viewpoint of charging and discharging at a high rate, it is preferable that the cross-sectional area of an elliptical truncated cone or an elliptical truncated cone, not shown, between the first negative electrode stem portion 32b and the negative electrode head portion 32a is equal to or smaller than the cross-sectional area of the negative electrode head portion 32a, larger than the cross-sectional area of the first negative electrode stem portion 32b, and larger than the cross-sectional area of the second negative electrode stem portion 32c. It is also preferable that the negative electrode shaft portion has an elliptical cross section, so that the positive electrode external terminal 17 is less likely to rotate.

Fig. 10 shows a cross-sectional view in the short axis direction (fig. 10 (a)) and a cross-sectional view in the long axis direction (fig. 10 (b)) of the negative electrode external terminal 32. The minor axis direction of the negative electrode external terminal 32 (minor axis direction of the first negative electrode shaft portion 32b and minor axis direction of the second negative electrode shaft portion 32 c) is a direction of a cross section passing through the center of the negative electrode shaft portion and having the smallest axial diameter of the negative electrode shaft portion. The long axis direction of the negative electrode external terminal 32 (the long axis direction of the first negative electrode shaft 32b and the long axis direction of the second negative electrode shaft 32 c) is a direction of a cross section passing through the center of the negative electrode shaft and having the maximum axial diameter of the negative electrode shaft. The short axis direction of the first negative electrode shaft portion 32b and the short axis direction of the second negative electrode shaft portion 32c are preferably the same direction. The longitudinal direction of the first negative electrode stem 32b is preferably the same as the longitudinal direction of the second negative electrode stem 32c. The short axis direction of the negative electrode external terminal 32 (the short axis direction of the first negative electrode shaft 32b and the short axis direction of the second negative electrode shaft 32 c) is the short side direction of the plane on the negative electrode shaft side of the negative electrode head portion 32a, and the long axis direction of the negative electrode external terminal 32 (the long axis direction of the first negative electrode shaft 32b and the long axis direction of the second negative electrode shaft 32 c) is the longitudinal direction of the plane on the positive electrode shaft side of the negative electrode head portion 32 a. The minor axis direction of the negative electrode external terminal 32 (the minor axis direction of the first negative electrode shaft 32b and the minor axis direction of the second negative electrode shaft 32 c) and the major axis direction of the negative electrode external terminal 32 (the major axis direction of the first negative electrode shaft 32b and the major axis direction of the second negative electrode shaft 32 c) are preferably parallel or substantially parallel (within ± 3 degrees of the angular difference) to the inclined surface 5d.

As shown in fig. 10, the length of the minor axis of the top surface of the first negative electrode tab 32b is Ca1, and the length of the major axis of the top surface of the first negative electrode tab 32b is Ca2. The length of the minor axis of the bottom surface of the first negative electrode shaft portion 32b is Cb1, and the length of the major axis of the bottom surface of the first negative electrode shaft portion 32b is Cb2. The length of the minor axis of the top surface of the second negative electrode shaft 32c is designated as Da1, and the length of the major axis of the top surface of the second negative electrode shaft 32c is designated as Da2. The length of the minor axis of the bottom surface of the second negative electrode shaft 32c is Db1, and the length of the major axis of the bottom surface of the second negative electrode shaft 32c is Db2.

Ca1 and Cb1 satisfy Ca 1< Cb1 (Ca 1. Ltoreq. Cb1 if the first negative electrode shaft portion 32b is a modified example of an elliptic cylinder). Ca2 and Cb2 satisfy Ca2 < Cb2 (Ca 2. Ltoreq. Cb2 if a modification example in which the first negative electrode shaft portion 32b is an elliptic cylinder is included). Da1 and Db1 satisfy Da 1< Db1.Da2 and Db2 satisfy Da2 < Db2.

Further, it is preferable that Ca1, ca2, da1, da2, db1 and Db2 satisfy | (Ca 1-Da 1) - (Ca 2-Da 2) | ≦ 0.1mm, and (Db 2-Da 2) < (Db 1-Da 1). If | (Ca 1-Da 1) - (Ca 2-Da 2) | ≦ 0.1mm, there is an advantage that the first negative electrode shaft portion 32b can be stably brought into contact with the negative electrode terminal lead 36. If (Db 2-Da 2) < (Db 1-Da 1) is satisfied, there is an advantage that the area of the contact portion between the second negative electrode shaft portion 32c and the negative electrode terminal lead 36 can be increased and the caulking portion can be made strong. From this viewpoint, it is more preferable that 1.2 (Db 2-Da 2) < (Db 1-Da 1) be satisfied.

In addition, ca1 and Ca2 preferably satisfy 1.1. Ltoreq. Ca2/Ca 1. Ltoreq.2.0. If Ca2/Ca1 is less than 1.1, the cross-sectional shape of the first negative electrode shaft portion 32b is close to a circle, and if Ca2/Ca1 is greater than 2.0, the long axis is too long, and the cross-sectional area is reduced. Therefore, the above range is preferably satisfied from the viewpoint of charge and discharge at a high rate.

In addition, cb1 and Cb2 preferably satisfy 1.08. Ltoreq. Cb2/Cb 1. Ltoreq.2.0. If Cb2/Cb1 is less than 1.08, the cross-sectional shape of the first negative electrode shaft portion 32b approaches a circle, and if Cb2/Cb1 is greater than 2.0, the long axis is too long, whereby the cross-sectional area becomes small. Therefore, the above range is preferably satisfied from the viewpoint of charge and discharge at a high rate.

Further, ca2 and Da2 satisfy 1.05. Ltoreq. Ca2/Da 2. Ltoreq.1.5, which has an advantage that the first negative electrode shaft portion 32b and the negative electrode terminal lead 36 can be stably brought into contact with each other. If Ca2/Da2 is less than 1.5, it is not preferable from the viewpoint of assemblability of the negative electrode terminal lead 36. When Ca2/Da2 is larger than 1.5, the sectional area becomes smaller when Ba2 is small, which is not preferable from the viewpoint of high-rate charge and discharge, and when Aa2 is large, the sealing portion of the insulating gasket 19 increases, which is not preferable from the viewpoint of airtightness.

In addition, the negative electrode shaft portion is preferably solid from the viewpoint of performing charge and discharge at a high rate. Solid means that the negative electrode shaft portion has substantially no void and is substantially made of metal or alloy. More preferably, the negative electrode external terminal 32 is solid as a whole.

As shown in fig. 7, a burring (annular rising portion) 31 extends from the peripheral edge of the through hole 31 toward the inside of the outer jacket material 1 and is formed by burring.

Fig. 9 shows a perspective view of the negative external terminal 32. As shown in fig. 7, 8 and 9, the negative electrode external terminal 32 includes, for example, a truncated pyramid-shaped negative electrode head portion 32a and a negative electrode shaft portion penetrating the through hole 30 of the first exterior covering portion 5. The columnar shaft portion extends from a plane parallel to and opposite from the top surface of the negative electrode head portion 32 a. The negative electrode external terminal 32 is formed of a conductive material such as aluminum or an aluminum alloy.

The negative electrode insulating member 33a has a through hole and a projection, and insulates the first exterior packaging part 5 from the negative electrode external terminal 32 and the negative electrode terminal lead 36. The negative electrode insulating member 33a is an annular member having a convex portion on the outer periphery. The convex portion of the negative electrode insulating member 33a extends in a direction opposite to the direction in which the negative electrode terminal lead 36 exists. The negative electrode insulating member 33a is an insulating member.

The negative electrode insulating member 33a having the convex portion is preferably made of at least 1 kind of resin material selected from the group consisting of a fluororesin, a fluororubber, a polyphenylene sulfide resin (PPS resin), a polyether ether ketone resin (PEEK resin), a polypropylene resin (PP resin), a polybutylene terephthalate resin (PBT resin), and the like, for example.

The negative electrode reinforcing member 33b is formed of, for example, a circular ring having a through hole and formed of a material having higher rigidity than the gasket. The negative electrode reinforcing member 33b is disposed between the first exterior cover 5 and the negative electrode insulating member 33 a. Examples of the material having higher rigidity than the gasket include stainless steel, a material plated with iron (e.g., ni, niCr, etc.), ceramics, and a resin capable of having higher rigidity than the gasket (e.g., polyphenylene sulfide (PPS), polybutylene terephthalate (PBT)). As shown in fig. 7, the negative electrode reinforcing member 33b is disposed on the outer peripheral surface of the burring 31 and contacts the burring 31 and the negative electrode insulating member 33 a. Since the outer jacket material 1 is a thin material, the first outer jacket 5 and the flange 31 are preferably reinforced by the negative electrode reinforcing member 33b.

The negative electrode external terminal 32 is inserted into the through hole of the negative electrode insulating member 33a and the through hole of the negative electrode reinforcing member 33b. The negative electrode reinforcing member 33b is sandwiched between the convex portion of the negative electrode insulating member 33a and the burring portion 31 of the first exterior covering 5. Even if the negative electrode terminal lead 36 partially moves, the negative electrode terminal lead 36 is more reliably prevented from being short-circuited with the first exterior package portion 5 by the negative electrode insulating member 33a, which is preferable. Further, it is preferable that the negative electrode insulating member 33a has a convex portion, because the reliability of insulation between the negative electrode terminal lead 36 and the first exterior packaging part 5 is improved.

As shown in fig. 3 and 7, the insulating spacer 34 is a cylindrical body (tube portion) having a flange portion 34a at one open end. As shown in fig. 3 and 7, the insulating spacer 34 has a cylindrical body part inserted into the through hole 30 and the burring part 31, and a flange part 34a disposed on the outer periphery of the through hole 30 on the outer surface of the first external packaging part 5. The insulating spacer 34 is formed of a resin such as a fluororesin, a fluororubber, a polyphenylene sulfide resin (PPS resin), a polyether ether ketone resin (PEEK resin), a polypropylene resin (PP resin), or a polybutylene terephthalate resin (PBT resin).

As shown in fig. 3 and 7, the negative electrode terminal insulating member 35 is a plate-like member bent at an obtuse angle, and has a through hole 35a at the bottom. The negative terminal insulating member 35 is disposed on the outer surface of the first exterior package 5. The flange portion 34a of the insulating spacer 34 is inserted into the through hole 35a of the negative terminal insulating member 35.

The negative terminal portion 4 further includes a negative terminal lead 36. The negative electrode terminal lead 36 is a conductive plate having a through hole 36a and a first extending portion 36b extending toward the opening 5a of the first exterior covering 5, that is, toward the second exterior covering 6. In fig. 6, the negative electrode terminal lead 36 has a first extension portion 36b extending toward the electrode group 2 side. The first extending portion 36b of the negative electrode terminal lead 36 is integrated with the first extending portion 14a of the electrode group-side negative electrode lead 14 by welding. The facing surfaces of the first extending portion 36b and the first extending portion 14a are welded, and further, the end surface of the first extending portion 36b on the tip side and the end surface of the first extending portion 14a are also welded. At least the first extending portion 36b of the negative electrode terminal lead 36 and the first extending portion 14a of the electrode group-side negative electrode lead 14 have their distal ends perpendicular or substantially perpendicular (80 ° or more and 100 ° or less) to the surface of the second exterior case 6. The first extending portion 36b of the negative electrode terminal lead 36 and at least the tip portion of the first extending portion 14a of the electrode group-side negative electrode lead 14 are perpendicular or substantially perpendicular to the surface of the second exterior cover 6, and are illustrated as being manufactured without bending the lead after the first extending portion 36b of the negative electrode terminal lead 36 and the first extending portion 14a of the electrode group-side negative electrode lead 14 are welded. The lead is bent after welding, which has an advantage that the wiring at the terminal portion of the electrode can be made compact, but the lead is required to be thin in thickness in order to be bent with high accuracy after welding. However, it is not preferable in that a large current is difficult to flow when the lead is made thin. By orienting the welded portion in the direction of the surface of the second exterior package 6, the thickness of the lead can be increased. The shapes of the electrode group-side negative electrode lead 14 and the negative electrode terminal lead 36, including the bent shape of the lead, are not limited to the shapes shown in fig. 7, and may be other shapes.

In view of the large current characteristics, the thickness of the negative electrode terminal lead 36 may be 0.5mm or more and 3.0mm or less, and the thickness of the electrode group-side negative electrode lead 14 may be 0.5mm or more and 3.0mm or less. Further, considering the lead bending step before the welding of the leads and the large current characteristic, the sum of the thickness of the negative electrode terminal lead 36 and the thickness of the electrode group-side negative electrode lead 14 is preferably 1.0mm to 1.2 mm.

Battery 100 further includes first negative terminal insulation reinforcing member 37. The first negative electrode insulation reinforcing member 37 is disposed on the inner surface side of the first exterior packaging part 5. More specifically, the first negative electrode insulation reinforcing member 37 is disposed on the inner surface side of the first exterior cover 5 between the negative electrode terminal lead 36 and the first exterior cover 5. As shown in fig. 3 and 7, the first negative terminal insulation reinforcing member 37 includes: a main body portion 37a having a structure in which a bottomed rectangular cylinder is half-divided in the longitudinal direction; a circular groove 37b formed in the body portion 37a; and a through hole 37c opened in the center of the circular groove 37 b. The negative electrode insulating member 33a, the negative electrode reinforcing member 33b, and the negative electrode external terminal 32 are disposed in the through hole 37c. The main body portion 37a of the first negative terminal insulation reinforcing member 37 covers the corner portion of the first external packaging part 5 connected from the short-side wall to the bottom surface and the corner portion of the first external packaging part 5 connected from the short-side wall to the long-side surface. This can reinforce the first external packaging member 5, particularly, the vicinity of the corner where the short-side wall and the long-side wall intersect with the bottom. The negative electrode insulating member 33b having a burring portion disposed on the outer peripheral surface of the burring portion 31 is disposed in the circular groove 37 b. The through hole 37c communicates with the opening of the cuff 31 and the through hole 30 of the first exterior package portion 5. The negative terminal lead 36 is disposed on the first negative terminal insulation reinforcing member 37. The through hole 36a of the negative electrode terminal lead 36 communicates with the through hole 37c of the first negative electrode terminal insulation reinforcing member 37, the opening of the burring 31, and the through hole 30 of the first exterior covering 5.

The second negative electrode insulation reinforcing member 38 paired with the first negative electrode insulation reinforcing member 37 is disposed on the inner surface side of the first exterior packaging part 5 and the inner surface side of the second exterior packaging part 6. As shown in fig. 3 and 7, the second negative electrode insulation reinforcing member 38 has a structure in which a bottomed rectangular tube is half-divided in the longitudinal direction. The first negative electrode insulation reinforcing member 37 covers the negative electrode current collector tab 8a from the winding center to about half of the first exterior covering portion 5. The other second insulation reinforcing member 38 covers about half of the negative electrode collector tab 8a from the winding center to the second exterior casing portion 6 side. This can reinforce the second exterior cover 6, particularly in the vicinity of the short side.

The shaft portion of the negative electrode external terminal 32 is inserted into the insulating spacer 34, the through hole 35a of the negative electrode terminal insulating member 35, the through hole 30 of the first exterior covering portion 5, the through hole 37c of the first negative electrode insulating reinforcing member 37, and the through hole 36a of the negative electrode terminal lead 36, and then is plastically deformed by caulking. As a result, as shown in fig. 3 and 7, these components are integrated, and the negative electrode external terminal 32 and the negative electrode terminal lead 36 are electrically connected. Therefore, the negative electrode external terminal 36 also functions as a rivet. The second negative electrode shaft portion 32c and the negative electrode terminal lead 36 are fixed by caulking, and at least a part or the whole of the inner wall of the through hole 36a of the negative electrode terminal lead 36 may be welded to the second negative electrode shaft portion 32c by laser or the like, whereby a stronger connection and an improvement in electrical conductivity are achieved.

The spare positive electrode lead 11, the electrode group-side positive electrode lead 12, the positive electrode terminal lead 23, the spare negative electrode lead 13, the electrode group-side negative electrode lead 14, and the negative electrode terminal lead 36 may be formed of, for example, aluminum or an aluminum alloy material. In order to reduce the contact resistance, the material of the lead is preferably the same as that of the positive electrode current collector or the negative electrode current collector that can be electrically connected to the lead.

The first positive electrode insulation reinforcing member 24, the second positive electrode insulation reinforcing member 25, the first negative electrode insulation reinforcing member 37, and the second negative electrode insulation reinforcing member 38 are formed of thermoplastic resin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polypropylene (PP), polyethylene (PE), nylon, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyphenylene Sulfide (PPs), and polyether ether ketone (PEEK), for example.

At the corner portion connecting the short side wall and the bottom of the first external packaging member 5, a gap is formed between the corner portion and the first end face 7a and between the corner portion and the second end face 8a of the electrode group 2. By providing the corner portion of the first external packaging member 5, which connects the short side wall and the bottom portion, with the concave portion protruding inward and providing the bottom portion of the concave portion with the inclined surface 5d, the dead space in the first external packaging member 5 is reduced, and therefore the volumetric energy density of the battery can be improved. In addition, by disposing the positive terminal portion 3 and the negative terminal portion 4 on the inclined surface 5d, the area for disposing the terminal portions can be increased as compared with the case where the positive terminal portion 3 and the negative terminal portion 4 are disposed on the short-side surface having no inclined surface. Therefore, the diameters of the shaft portion of the positive electrode external terminal 17 and the shaft portion of the negative electrode external terminal 32 can be increased, and thus a large current (high-rate current) can flow at low resistance.

The first exterior cover 5 and the second exterior cover 6 made of stainless steel are easy to weld and can be sealed by inexpensive resistance seam welding. Therefore, the outer jacket material 1 having a gas tightness higher than that of the laminated film container can be realized at low cost. In addition, the heat resistance of outer jacket material 1 can be improved. For example, SUS304 has a melting point of 1400 ℃ and Al has a melting point of 650 ℃.

In addition, plastic deformation occurs as a result of the shaft portion of the external terminal being caulked and fixed to the through hole. As a result, although a force is applied in the radial direction of the insulating spacer, since the burring part is reinforced by the annular member disposed outside the burring part, a compressive stress is generated in the insulating spacer, and the external terminal and the first external packaging part 5 can be connected with high strength. Even if the plate thickness of the first external packaging member 5, that is, the plate thickness of the flange portion is reduced, the flange portion can be reinforced by the annular member, and therefore, the external terminal can be connected to the first external packaging member 5 with high strength regardless of the plate thickness of the first external packaging member 5. Further, since the burring extends from the edge of the through hole toward the inside of the outer jacket material 1, liquid leakage when the internal pressure of the outer jacket material 1 rises due to gas generation or the like can be suppressed by the action of external pressure. Therefore, high reliability can be achieved even when the thicknesses of the first external packaging layer 5 and the second external packaging layer 6 are reduced.

Therefore, according to the battery of the first embodiment, since high strength and reliability can be obtained even when the thicknesses of the first exterior cover portion 5 and the second exterior cover portion 6 are made thin, the battery having excellent flexibility and heat dissipation properties and high strength and reliability can be provided.

If the first external packaging member 5 has a depth equal to or less than the maximum length of the opening 5a, the area of the opening 5a of the first external packaging member 5 increases. The second exterior cover 6 is welded to the four sides of the first exterior cover, but if the area of the opening 5a is increased, the length of the welded side is increased, and therefore, it is easy to weld the three sides first and inject the electrolyte from the gap of the remaining side. Further, since the outer jacket material 1 can be temporarily sealed by providing a portion having a lower welding strength than the other portions, a member for temporary sealing (for example, a rubber plug) can be eliminated. Further, since the outer jacket material 1 has a flat shape, the heat dissipation performance of the battery can be improved.

The first external packaging member 5 includes a concave portion having an inclined surface 5d, and a terminal portion is disposed on the inclined surface 5d, thereby reducing a dead space in the first external packaging member 5.

The inclined surface 5d is not limited to being provided near the center of the short side of the outer jacket material 1, and may extend over the entire short side of the outer jacket material 1.

Preferably, a spare positive electrode lead 11 electrically connected to the positive electrode current collector tab 7a and a spare negative electrode lead 13 electrically connected to the negative electrode current collector tab 8a are further provided, and the electrode terminal lead and the spare lead are electrically connected. This facilitates positioning during welding. In addition, even if the spare lead is slightly displaced from the positions of the positive electrode current collector tab 7a and the negative electrode current collector tab 8a, a sufficient connection area can be secured, and therefore a low-resistance battery can be realized.

The first end face of the external terminal has a quadrangular tip end face and first and second inclined faces connected to two mutually opposed sides of the tip end face, whereby any one of the three faces can be selected as a welding face to change a welding direction.

The outer shape of the annular member does not necessarily have to be the same shape as the cross-sectional shape of the cuff, and may be a polyhedron such as a rectangle or a hexagon, or may be a complex shape of one or more curved lines and one or more straight lines.

The spare positive electrode lead 11 and the spare negative electrode lead 13 are not limited to the U-shaped conductive plates, and conductive flat plates may be used. Alternatively, the spare positive electrode lead 11 or the spare negative electrode lead 13 or both may not be used.

The outer jacket material 1 may further include a safety valve or the like capable of releasing the pressure inside the battery when the internal pressure of the battery rises to a predetermined value or more.

The battery of the first embodiment may be a primary battery, or may be a secondary battery. As an example of the battery of the first embodiment, a lithium ion secondary battery is cited.

The positive electrode 7, the negative electrode 8, the separator, and the nonaqueous electrolyte of the battery of the first embodiment will be described below.

1) Positive electrode 7

The positive electrode 7 may include, for example, a positive electrode current collector, a positive electrode material layer held by the positive electrode current collector, and a positive electrode current collector tab. The positive electrode material layer may contain, for example, a positive electrode active material, a conductive agent, and a binder.

As the positive electrode active material, for example, an oxide or a sulfide can be used. Examples of the oxide and sulfide include lithium-intercalated manganese dioxide (MnO) ₂ ) Iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (e.g., li) _x Mn ₂ O ₄ Or Li _x MnO ₂ ) Lithium nickel composite oxide (e.g., li) _x NiO ₂ ) Lithium cobalt composite oxide (e.g., li) _x CoO ₂ ) Lithium nickel cobalt complex oxide (e.g., liNi) _1-y Co _y O ₂ ) Lithium manganese cobalt composite oxide (e.g., li) _x Mn _y Co _1-y O ₂ ) Lithium manganese nickel composite oxide having spinel structure (e.g., li) _x Mn _2-y Ni _y O ₄ ) Lithium phosphorus oxide having an olivine structure (e.g., li) _x FePO ₄ 、Li _x Fe _1- _y Mn _y PO ₄ 、Li _x CoPO ₄ ) Iron (Fe) sulfate ₂ (SO ₄ ) ₃ ) Vanadium oxide (e.g. V) ₂ O ₅ ) And lithium nickel cobalt manganese composite oxides. In the formula, x is more than 0 and less than or equal to 1,0 and less than or equal to y is less than or equal to 1. These compounds may be used alone or in combination as an active material.

The binder is blended to bind the active material to the current collector. Examples of the binder include Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

The conductive agent is blended as necessary to improve the current collecting performance and to suppress the contact resistance between the active material and the current collector. Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, and graphite.

In the positive electrode material layer, the positive electrode active material and the binder are preferably blended in a proportion of 80 mass% or more and 98 mass% or less and 2 mass% or more and 20 mass% or less, respectively.

By setting the amount of the binder to 2% by mass or more, sufficient electrode strength can be obtained. Further, by setting the content to 20 mass% or less, the amount of the insulating material of the electrode is reduced, and the internal resistance can be reduced.

When the conductive agent is added, the positive electrode active material, the binder, and the conductive agent are preferably blended in a proportion of 77 mass% or more and 95 mass% or less, 2 mass% or more and 20 mass% or less, and 3 mass% or more and 15 mass% or less, respectively. The above-described effects can be exhibited by setting the amount of the conductive agent to 3 mass% or more. Further, by setting the content to 15% by mass or less, the decomposition of the nonaqueous electrolyte on the surface of the positive electrode conductive agent during high-temperature storage can be reduced.

The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil including at least 1 element selected from Mg, ti, zn, ni, cr, mn, fe, cu, and Si.

The positive electrode current collector is preferably integrated with a positive electrode current collector tab. Alternatively, the positive electrode current collector may be separate from the positive electrode current collector tab.

2) Negative electrode 8

The negative electrode 8 may include, for example, a negative electrode current collector, a negative electrode material layer held by the negative electrode current collector, and a negative electrode current collector tab. The anode material layer may include, for example, an anode active material, a conductive agent, and a binder.

As the negative electrode active material, for example, a metal oxide, a metal nitride, an alloy, carbon, or the like, which can intercalate and deintercalate lithium ions, can be used. Preferably 0.4V or more (for Li/Li) ⁺ ) A substance capable of intercalating and deintercalating lithium ions at a high potential is used as the negative electrode active material.

Examples of the negative electrode active material include a graphite material, a carbonaceous material (e.g., graphite, coke, carbon fiber, spherical carbon, a thermally decomposed gaseous carbonaceous material, a resin-fired material, etc.), a chalcogen compound (e.g., titanium disulfide, molybdenum disulfide, niobium selenide, etc.), a light metal (e.g., aluminum alloy, magnesium alloy, lithium alloy, etc.), and Li _4+x Ti ₅ O ₁₂ (x varies in the range of-1. Ltoreq. X. Ltoreq.3 depending on charge-discharge reaction) and spinel-type lithium titanate and ramsdellite-type Li _2+x Ti ₃ O ₇ (x varies in the range of-1. Ltoreq. X. Ltoreq.3 depending on charge-discharge reaction), a metal composite oxide containing at least 1 element selected from the group consisting of Ti and P, V, sn, cu, ni, and Fe, a niobium-titanium composite oxide, and the like.

Examples of the metal composite oxide containing at least 1 element selected from the group consisting of Ti, P, V, sn, cu, ni and Fe include TiO ₂ -P ₂ O ₅ 、TiO ₂ -V ₂ O ₅ 、TiO ₂ -P ₂ O ₅ -SnO ₂ 、TiO ₂ -P ₂ O ₅ -MO (M is at least 1 element selected from the group consisting of Cu, ni and Fe). These metal composite oxides are intercalated with lithium due to charging, thereby changing to lithium titanium composite oxides. Optimized bagIncluding 1 or more of lithium titanium oxide (e.g., spinel-type lithium titanate), silicon, tin, and the like. The binder of the negative electrode active material layer is common to the binder of the positive electrode active material layer. The conductive agent of the negative electrode active material layer is common to the conductive agent of the positive electrode active material layer.

As the niobium-containing titanium composite oxide, for example, a compound having the general formula Li _a TiM _b Nb _2±β O _7±σ (the values of the subscripts are 0. Ltoreq. A.ltoreq.5, 0. Ltoreq. B.ltoreq.0.3, 0. Ltoreq. Beta.ltoreq.0.3, 0. Ltoreq. Sigma.ltoreq.0.3, M is a composite oxide having a monoclinic crystal structure represented by at least 1 kind (may be 1 kind or may be plural kinds) selected from the group consisting of Fe, V, mo and Ta, and a composite oxide having a crystal structure represented by the general formula Li _2+a1 M(I) _2-b1 Ti _6-c1 M(II) _d1 O _14+σ1 (the subscripts are in the ranges of 0. Ltoreq. A1. Ltoreq.6, 0. Ltoreq. B1. Ltoreq.2, 0. Ltoreq. C1. Ltoreq.6, 0. Ltoreq. D1. Ltoreq.6, and-0.5. Ltoreq. Sigma.1. Ltoreq.0.5. Ltoreq.M (I) is at least 1 kind (may be 1 kind or may be plural kinds) selected from the group consisting of Sr, ba, ca, mg, na, cs, and K, and M (II) is at least 1 kind (may be 1 kind or may be plural kinds) selected from the group consisting of Zr, sn, V, nb, ta, mo, W, fe, co, mn, and Al), and a composite oxide having an orthorhombic crystal structure represented by Nb) can be used. In the above general formula Li _2+a1 M(I) _2-b1 Ti _6-c1 M(II) _d1 O _14+σ1 In the above formula, the subscripts have values of 0. Ltoreq. A1. Ltoreq.6, 0. Ltoreq. B1. Ltoreq.2, 0. Ltoreq. C1. Ltoreq.6, 0. Ltoreq. D1. Ltoreq.6, and-0.5. Ltoreq. σ 1. Ltoreq.0.5, and M (I) is a combination of at least 1 kind (may be 1 kind or plural kinds) selected from the group consisting of Sr, ba, ca, mg, na, cs and K, and M (II) is Nb, or at least 1 kind (may be 1 kind or plural kinds) selected from the group consisting of Nb, zr, sn, V, ta, mo, W, fe, co, mn and Al. In particular, a monoclinic niobium-titanium composite oxide is more preferable because it has a large capacity per unit weight and can improve the battery capacity.

The conductive agent is added to improve the current collecting performance and suppress the contact resistance between the negative electrode active material and the current collector. Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, and graphite.

The binder is added to fill the gaps between the dispersed negative electrode active material and to bind the negative electrode active material to the current collector. Examples of the binder include Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-based rubber, and styrene butadiene rubber.

The active material, the conductive agent, and the binder in the negative electrode material layer are preferably blended in a proportion of 68 mass% or more and 96 mass% or less, 2 mass% or more and 30 mass% or less, and 2 mass% or more and 30 mass% or less, respectively. By setting the amount of the conductive agent to 2 mass% or more, the current collecting performance of the negative electrode layer can be improved. In addition, by setting the amount of the binder to 2% by mass or more, the adhesion between the negative electrode material layer and the current collector can be sufficiently expressed, and excellent cycle characteristics can be expected. On the other hand, in order to achieve a higher capacity, it is preferable that the conductive agent and the binder are each 28 mass% or less.

As the current collector, a material electrochemically stable at the insertion potential and the extraction potential of lithium of the negative electrode active material is used. The current collector is preferably made of copper, nickel, stainless steel, or aluminum, or an aluminum alloy containing at least 1 element selected from Mg, ti, zn, mn, fe, cu, and Si. The thickness of the current collector is preferably in the range of 5 to 20 μm. The current collector having such a thickness can balance the strength and weight of the negative electrode.

The negative electrode current collector is preferably integrated with a negative electrode current collector tab. Alternatively, the negative electrode current collector may be separate from the negative electrode current collector tab.

The negative electrode 8 is produced, for example, by suspending a negative electrode active material, a binder, and a conductive agent in a common solvent to prepare a slurry, applying the slurry on a current collector and drying it, and performing pressing after forming a negative electrode material layer. The negative electrode 8 may be produced by forming a negative electrode active material, a binder, and a conductive agent into a particulate form to prepare a negative electrode material layer, and disposing the negative electrode material layer on a current collector.

3) Diaphragm

Is a porous and thin insulating film. As the separator, there are included: nonwoven fabrics, films, papers, inorganic particle layers, and the like, which comprise extremely thin nanofiber films made of resins. Examples of the material constituting the separator include polyolefins such as polyethylene and polypropylene, cellulose, polyester, polyvinyl alcohol, polyimide, polyamide, polyamideimide, polytetrafluoroethylene, and vinylon. Examples of the separator that is preferable from the viewpoint of the thinness and the mechanical strength include nonwoven fabrics including cellulose fibers. The inorganic particle layer includes oxide particles, a thickener, and a binder. As the oxide particles, metal oxides such as aluminum oxide, titanium oxide, magnesium oxide, zinc oxide, and barium sulfate can be used. Carboxymethyl cellulose may be used as the thickener. As the binder, methyl acrylate or an acrylic copolymer containing the same, styrene Butadiene Rubber (SBR), or the like can be used.

4) Electrolyte

The electrolyte is preferably a solution containing an electrolyte salt and a nonaqueous solvent, a nonaqueous gel-like electrolyte in which a polymer material is combined with a solution containing an electrolyte salt and a nonaqueous solvent, a solution containing an electrolyte salt and water, or an aqueous gel-like electrolyte in which a polymer material is combined with a solution containing an electrolyte salt and water.

As the electrolyte salt contained in the nonaqueous solution, for example, liPF can be used ₆ 、LiBF ₄ 、Li(CF ₃ SO ₂ ) ₂ N (lithium bistrifluoromethanesulfonamide; commonly known as LiTFSI), liCF ₃ SO ₃ (generic name LiTFS), li (C) ₂ F ₅ SO ₂ ) ₂ N (lithium bis-pentafluoroethane sulfonamide; commonly known as LiBETI), liClO ₄ 、LiAsF ₆ 、LiSbF ₆ 、LiB(C ₂ O ₄ ) ₂ (lithium bis (oxalato) borate; commonly known as LiBOB), difluoro (trifluoro-2-oxide-2-trifluoro-methylpropanesulfonic acid (2-) -0,0), liBF ₂ OCOOC(CF ₃ ) ₂ (lithium borate; commonly known as LiBF) ₂ (HHIB)), and the like. One kind of these electrolyte salts may be used, or two or more kinds may be used in combination. Particularly preferred is LiPF ₆ 、LiBF ₄ . The lithium salt may use a supporting salt that conducts electricity to ions. For example, lithium hexafluorophosphate (LiPF) can be mentioned ₆ ) Boron tetrafluorideLithium oxide, imide-based supporting salts, and the like. The lithium salt may contain 1 or 2 or more species.

The concentration of the nonaqueous electrolyte salt is preferably in the range of 0.5mol/L to 3.0mol/L, and more preferably in the range of 0.7mol/L to 2.0 mol/L. By defining the electrolyte concentration in this manner, the performance when a high load current flows can be further improved while suppressing the influence of an increase in viscosity due to an increase in the electrolyte salt concentration.

The nonaqueous solvent is not particularly limited, and for example, cyclic carbonates such as Propylene Carbonate (PC) and Ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), linear carbonates such as methylethyl carbonate (MEC) and dipropyl carbonate (DPC), 1,2-Dimethoxyethane (DME), γ -butyrolactone (GBL), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeHF), 1,3-dioxolane, sulfolane, and Acetonitrile (AN) can be used. One of these solvents may be used, or two or more of them may be used in combination. The nonaqueous solvent containing a cyclic carbonate and/or a chain carbonate is preferable. Examples of the polymer material contained in the nonaqueous gel electrolyte include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and polymethacrylate.

Examples of the electrolyte salt contained in the aqueous solution include LiCl, liBr, liOH and Li ₂ SO ₄ 、LiNO ₃ 、LiN(SO ₂ CF ₃ ) ₂ (trifluoromethanesulfonylamide; commonly known as LiTFSA), liN (SO) ₂ C ₂ F ₅ ) ₂ (bis (pentafluoroethanesulfonyl) amide; commonly known as LiBETA), liN (SO) ₂ F) ₂ (bis-fluorosulfonyl amide; commonly known as LiFSA), liB [ (OCO) ₂ ] ₂ And the like. The kind of the lithium salt to be used may be 1 kind or 2 or more kinds. Examples of the polymer material contained in the aqueous gel electrolyte include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and polymethacrylate.

The concentration of the aqueous electrolyte salt is preferably 1mol/L to 12mol/L, and more preferably 112mol/L to 10 mol/L. In order to suppress electrolysis of the electrolytic solution, an additiveLiOH、Li ₂ SO ₄ And adjusting the pH value. The pH value is preferably 3 or more and 13 or less, and more preferably 4 or more and 12 or less.

Alternatively, as the nonaqueous electrolyte, an ambient temperature molten salt (ionic melt) containing lithium ions, a polymer solid electrolyte, an inorganic solid electrolyte, or the like may be used.

The normal temperature molten salt (ionic melt) is a compound that can exist as a liquid at normal temperature (15 to 25 ℃) in an organic salt composed of a combination of organic cations and anions. The ambient temperature molten salt includes an ambient temperature molten salt in which a monomer exists as a liquid, an ambient temperature molten salt which becomes a liquid by being mixed with an electrolyte, and an ambient temperature molten salt which becomes a liquid by being dissolved in an organic solvent. Generally, an ambient temperature molten salt used in a nonaqueous electrolyte battery has a melting point of 25 ℃ or lower. In addition, the organic cation typically has a 4-stage ammonium backbone.

The method for manufacturing the battery of the first embodiment is explained below. Fig. 12, fig. 13 (a) to 13 (b), and fig. 14 (a) to 14 (d) show process diagrams for manufacturing a battery.

The electrode group 2 illustrated in fig. 5 is produced. In addition, the first exterior packaging part 5 to which the positive terminal part 3 and the negative terminal part 4 are fixed is manufactured as illustrated in fig. 12. In addition, at least one guide hole for positioning is opened in each of the first exterior cover 5 and the second exterior cover 6. An example thereof is shown in fig. 13 (a) and 13 (b). Fig. 13 (a) shows an example in which guide holes 39 for positioning are opened at four corners of the second exterior cover 6. Fig. 13 (b) shows an example in which guide holes 39 for positioning are opened at four corners of the first exterior packaging part 5.

The electrode group 2 wound with the insulating film 26 is housed in the first exterior packaging part 5, and the electrode group-side positive electrode lead 12 and the positive electrode terminal lead 23 are joined by welding or the like, and the electrode group-side negative electrode lead 14 and the negative electrode terminal lead 36 are joined by welding or the like. The joining may be performed by laser welding, TIG welding, or friction stir welding, for example. In the embodiment, any of the joints is treated as a weld.

Next, the second positive electrode insulation reinforcing member 25 and the second negative electrode insulation reinforcing member 38 are covered on the positive electrode collector tab 7a and the negative electrode collector tab 8a of the electrode group 2. Next, the second exterior cover 6 is disposed on the first exterior cover 5. Since the guide holes 39 are opened at the four corners of each of the first exterior packaging member 5 and the second exterior packaging member 6, the position of the second exterior packaging member 6 with respect to the first exterior packaging member 5 can be easily determined.

Next, as shown in fig. 14 (a), three sides (for example, two sides of the long side and the short side) of the first external packaging body 5 and the second external packaging body 6 are welded. The welding is, for example, resistance seam welding. The welding site is indicated by reference numeral 40. The welding point 40 is preferably located inside the outer edges of the first external packaging member 5 and the second external packaging member 6.

After injecting the electrolyte solution from the opening of the unwelded one side, the one side is welded by, for example, resistance seam welding as shown in fig. 14 (b). The welded portion 41 is preferably an outer edge portion of the first exterior cover 5 and the second exterior cover 6.

Next, after aging and initial charge and discharge are performed, as shown in fig. 14 (c), a cut portion 42 is formed by cutting a part of the welded portion 41, and the gas in the exterior member 1 is released. Then, as shown in fig. 14 (d), welding is performed by a welding portion (a long side of the second exterior packaging part 6) 43 on the inner side of the welding portion 41 by resistance seam welding or the like. The welding is preferably performed in a reduced pressure atmosphere.

Then, the guide hole 39 can be removed by cutting the vicinity of the outer edges of the first and second

external packaging members

5 and 6 as necessary. In addition, the guide hole 39 may be left.

By the method described above, the battery of the first embodiment can be manufactured with high productivity.

The battery of the first embodiment can include a plurality of electrode groups 2 in one exterior member 1. In this case, as the second exterior cover 6, it is preferable to use an exterior cover having a flange portion at an opening portion, as in the first exterior cover 5.

When a plurality of electrode groups 2 are housed in one outer package, the plurality of electrode groups 2 may be connected in series or in parallel with each other. Fig. 15A to 15D show process diagrams for manufacturing the positive electrode side of a battery form in which a plurality of (2) electrode groups 2 are connected in parallel with each other. Fig. 15D shows the fabricated battery 101. A plurality of electrode groups 2 are prepared, and the center distal ends of the positive electrode current collecting tabs 7a are bundled by a spare positive electrode lead 11. Next, as shown in fig. 15A, the spare positive electrode lead 11 and the electrode group-side positive electrode lead 12 are welded. After welding, the electrode group-side positive electrode lead 12 is bent to form a first extended portion 12 as shown in fig. 15B. Alternatively, the electrode-side positive electrode lead bent in advance may be welded to the spare positive electrode lead 11 to obtain a member as shown in fig. 15B.

Then, the component of fig. 15B is inserted from the opening 5a side of the first outer package 5 in which the positive terminal portion 3 is previously incorporated. After the insertion, the first extension 12a of the electrode group-side positive electrode lead 12 and the first extension of the positive electrode terminal lead 23 are fixed by laser welding, and one electrode group 2 is fixed in the first exterior cover 5 as shown in fig. 12C. Similarly, the battery 101 in which the plurality of electrode groups 2 are housed as shown in fig. 15D can be obtained by inserting the other electrode group 2 into the first exterior case 5, performing laser welding, and covering with the second exterior case 6. By changing the orientation of the electrodes of the plurality of electrode groups 2, the series connection can be realized.

Fig. 16 shows a modification of the positive electrode portion of the battery 100 according to the first embodiment. The negative electrode side, not shown, is formed symmetrically to the positive electrode portion of fig. 16. The battery 102 of fig. 16 is the same as the battery 100 of the basic form shown in fig. 1 to 15, except that the first positive electrode shaft portion 17b and the first negative electrode shaft portion 32b are elliptical cylindrical platforms. Fig. 16 is a cross-sectional view of the positive electrode portion in the modification of the first embodiment, taken along the longitudinal direction of the battery. The virtual line (dashed line) of B-B' is shown in FIG. 16.

Fig. 17 is a cross-sectional view taken along the plane B-B' on the positive electrode side in fig. 16. The B-B' plane is a cross section passing through the center of the positive electrode terminal 17 (the center of the inclined surface 5 d). Fig. 17 is a cross-sectional view taken along plane B-B', that is, a cross-sectional view taken along a virtual line in the depth direction of battery 100 (the direction from the positive terminal toward the negative terminal). The positive electrode side and the negative electrode side are symmetrical, and therefore a cross-sectional view of the B-B' plane of the negative electrode side is not shown, and the structure of the negative electrode side can be understood by referring to the drawings on the positive electrode side.

Fig. 18 is a perspective view of a positive electrode external terminal (negative electrode external terminal) of a battery according to a modification of the first embodiment. In the perspective view of the positive electrode external terminal 17 shown in fig. 18, the first positive electrode shaft portion 17b has an elliptical truncated cone shape. Fig. 19 shows a cross-sectional view (a) in the short axis direction and a cross-sectional view (b) in the long axis direction of the positive electrode external terminal (negative electrode external terminal) shown in fig. 18. As shown in fig. 16 to 19, the first positive electrode shaft portion 17b is an elliptical cylindrical table, and therefore satisfies the relationship of Aa1= Ab1 and Aa2= Ab2. Similarly, on the negative electrode side, the first negative electrode shaft portion 32b has an elliptical cylindrical shape, and therefore satisfies the relationships Ca1= Cb1 and Ca2= Cb2. By forming the first positive electrode shaft portion 17b and the first negative electrode shaft portion 32b as elliptical columnar tables, the shape and the like of the

gaskets

19 and 34 are simplified, and the yield is improved. In the modification, it is also preferable from the viewpoint of performing charge and discharge at a high rate by making the cross section of the shaft portion elliptical.

(second embodiment)

The battery 100 of the second embodiment is a prismatic battery 200. The battery 100 of the first embodiment and the battery 200 of the second embodiment have different external shapes, but the cross section of the electrode shaft portion has an elliptical shape in common. In the first and second embodiments, the same reference numerals and the same names are used for the same members, but the functions and materials are the same. In the first and second embodiments, common contents are not described in part.

Fig. 20 shows a schematic perspective view of a battery 200 according to a second embodiment. Fig. 21 shows an expanded perspective view of the battery 200 shown in fig. 20. Fig. 22 is an expanded perspective view of a part of the battery 200 shown in fig. 20.

The battery 200 shown in fig. 20 has a first exterior packaging part 5 provided with the positive terminal part 3 and the negative terminal part 4, and a second exterior packaging part 6 with a bottom. The second exterior packaging member 6 is a so-called battery can, and the first exterior packaging member 5 serves as a cover for the second exterior packaging member 6. The safety valve 9, the electrolyte injection port 10, the positive electrode external terminal 17, the positive electrode terminal insulating member 20, the negative electrode external terminal 32, and the negative electrode terminal insulating member 35 can be confirmed in the appearance of the battery 200. The safety valve 9 is a safety device capable of releasing gas inside the battery 200 to reduce the pressure when the pressure inside the battery 200 rises. The electrolyte injection port 10 is a through hole for inserting the electrolyte into the battery 200 after sealing the first exterior cover 5 and the second exterior cover 6, and is sealed after injecting the electrolyte.

Fig. 21 is a perspective view of a part of the battery 200, and the electrode group 2 is connected to the first exterior cover 5 as a cover. The positive electrode collector tab 7a side of the electrode group 2 is covered and protected by a positive electrode internal insulating member 26. The negative electrode collector tab 8a side of the electrode group 2 is covered and protected by a negative electrode internal insulating member 27. The electrode group 2 is accommodated in a space formed by welding the first exterior case portion 5 and the second exterior case portion 6, the space having the opening 28 of the second exterior case portion 6.

Fig. 22 is a perspective view further developed from the upper part of fig. 21. In the developed view shown in fig. 22, the components constituting the positive terminal portion 3 and the negative terminal portion 4 are shown separately. Fig. 23 is a cross-sectional view showing a state in which the terminal portion is fixed to the first exterior packaging part 5 of the battery 200 shown in fig. 20. The sectional view of fig. 23 is a section including the center of the positive electrode external terminal 17 and the center of the negative electrode external terminal 32. The electrode group 2 is also fixed to the first exterior covering portion 5, but the electrode group 2 is not shown in the cross section of fig. 23 because the electrode group-side positive electrode lead 12 and the electrode group-side negative electrode lead 14 to which the electrode group 2 is fixed are not included. Fig. 24 (a) is a cross-sectional view of a part of the battery obtained when the battery is cut along the plane C-C' of fig. 23. Fig. 24 (b) shows a cross-sectional view of a part of the battery obtained when the battery is cut along the plane D-D' of fig. 23.

The battery 200 shown in fig. 20 to 24 includes: the exterior member 1 includes a first exterior member 5 and a second exterior member 6, a flat electrode group 2, an electrode group-side positive electrode lead 12 electrically connected to a positive electrode collector tab 7a of the electrode group 2, an electrode group-side negative electrode lead 14 electrically connected to a negative electrode collector tab 8a of the electrode group 2, a positive electrode terminal portion 3, and a negative electrode terminal portion 4.

As shown in fig. 23 and fig. 5 for reference, the electrode group 2 has a flat shape and includes a positive electrode 7, a negative electrode 8, and a separator 9 disposed between the positive electrode 7 and the negative electrode 8. The flat electrode group 2 includes a positive electrode 7, a positive electrode collector tab 7a electrically connected to the positive electrode 7, a negative electrode 8, and a negative electrode collector tab 8a electrically connected to the negative electrode 8, and the positive electrode collector tab 7a wound in a flat shape is located on a first end surface, and the negative electrode collector tab 8a wound in a flat shape is located on a second end surface.

The first exterior packaging part 5 has a through-hole 15 on the positive collector tab side in the positive terminal part 3. The positive electrode external terminal 17 of the positive electrode terminal portion 3 includes a positive electrode head portion 17a and a positive electrode shaft portion extending from the positive electrode head portion 17 a. The positive terminal part (3) includes a positive terminal lead (23) having a through hole (23 a). In the positive terminal portion 3, the positive head portion 17a protrudes outward from the first exterior cover 5, the positive shaft portion is inserted into the through hole 23a of the positive terminal lead 23, and the positive shaft portion is swaged and fixed to the first exterior cover 5 and the positive terminal lead 23. The two electrode group-side positive electrode leads 12 are directly electrically connected to the positive electrode terminal lead 23. The positive electrode current collector tab 7a is electrically connected to the two electrode group-side positive electrode leads 12 so as to sandwich the positive electrode current collector tab 7 a. A U-shaped spare positive electrode lead 11 is provided, for example, at a portion of the positive electrode current collector tab 7 a. The electrode group-side positive electrode lead 12 and the positive electrode collector tab 7a are electrically connected via a spare positive electrode lead 11. The top and bottom surfaces of the positive electrode shaft portion of the second embodiment are also the same as those of the first embodiment.

The positive electrode head 17a is flat and disposed so as to be partially embedded in the recess of the positive electrode terminal insulating member 20. A positive electrode terminal insulating member 20 and an insulating spacer 19 are disposed in a recessed portion around the through hole 15 on the positive electrode current collector tab 7a side of the first external packaging member 5. In the first embodiment, the positive electrode insulating member 18a is annular, but in the second embodiment, the positive electrode terminal lead 23 is covered, and the surface of the positive electrode terminal lead 23 facing the first exterior cover 5 is not short-circuited with the first exterior cover 5. The positive electrode insulating member 18a also has a wall surface facing the second external packaging member 6 so that the positive electrode terminal lead 23 does not short-circuit the second external packaging member 6. Further, the positive electrode insulating member 18a and the negative electrode insulating member 33a are preferably connected to each other.

Fig. 25 is a perspective view of the positive electrode external terminal 17. As shown in fig. 20 to 25, the positive electrode external terminal 17 includes, for example, a flat plate-shaped positive electrode head portion 17a and a positive electrode shaft portion. The positive electrode shaft portion protrudes from a plane parallel to and on the opposite side of the top surface of the positive electrode head portion 17 a. The positive electrode shaft portion has a first positive electrode shaft portion 17b of an elliptical truncated cone or an elliptical cylindrical truncated cone and a second positive electrode shaft portion 17c of an elliptical truncated cone.

Fig. 26 (a) shows a cross-sectional view of the positive electrode external terminal 17 in the short axis direction, and fig. 26 (b) shows a cross-sectional view of the positive electrode external terminal 17 in the long axis direction. In the second embodiment, as in the first embodiment, the length of the short axis of the top surface of the first positive electrode shaft portion 17b is defined as Aa1, and the length of the long axis of the top surface of the first positive electrode shaft portion 17b is defined as Aa2. The length of the short axis of the bottom surface of first positive electrode shaft 17b is Ab1, and the length of the long axis of the bottom surface of first positive electrode shaft 17b is Ab2. The length of the minor axis of the top surface of the second positive electrode shaft 17c is Ba1, and the length of the major axis of the top surface of the second positive electrode shaft 17c is Ba2. The length of the minor axis of the bottom surface of the second positive electrode shaft 17c is Bb1, and the length of the major axis of the bottom surface of the second positive electrode shaft 17c is Bb2. The second embodiment is the same as the first embodiment with respect to the preferable relationship among Aa1, aa2, ab1, ab2, ba1, ba2, bb1, and Bb2.

The minor axis direction of the positive electrode external terminal 17 (minor axis direction of the first positive electrode shaft 17b and minor axis direction of the second positive electrode shaft 17 c) and the major axis direction of the positive electrode external terminal 17 (major axis direction of the first positive electrode shaft 17b and major axis direction of the second positive electrode shaft 17 c) are preferably parallel or substantially parallel (within ± 3 degrees of angular difference) to the outer surface of the first exterior package part 5 and the bottom surface of the second exterior package part 6.

In the negative terminal portion 4, the first exterior covering portion 5 has a through-hole 30 on the negative electrode current collector tab 8a side. The negative external terminal 32 of the negative terminal portion 4 includes a negative head portion 32a and a negative shaft portion extending from the negative head portion 32 a. The negative terminal portion 4 includes a negative terminal lead 36 having a through hole 36 a. In the negative terminal portion 4, the negative head portion 32a protrudes outward from the first exterior covering portion 5, the negative shaft portion is inserted into the through hole 36a of the negative terminal lead 36, and the negative shaft portion is fixed to the first exterior covering portion 5 and the negative terminal lead 36 by caulking. The two electrode group-side negative electrode leads 14 are directly electrically connected to the negative electrode terminal lead 36. The negative electrode current collector tab 8a is electrically connected to the two electrode group-side negative electrode leads 14 so as to sandwich the negative electrode current collector tab 8a. A spare negative electrode lead 12, for example, U-shaped, is provided at a part of the negative electrode current collector tab 8a. The electrode group-side negative electrode lead 14 and the negative electrode collector tab 8a are electrically connected via the spare negative electrode lead 12. The top and bottom surfaces of the negative electrode shaft portion of the second embodiment are also the same as those of the first embodiment.

The negative electrode head 32a is flat and is disposed so as to be partially embedded in the recess of the negative electrode terminal insulating member 35. A negative electrode terminal insulating member 35 and an insulating spacer 34 are disposed in a recess around the through hole 30 on the negative electrode collector tab 8a side of the first exterior covering member 5. In the first embodiment, the negative electrode insulating member 33a is annular, but in the second embodiment, it is configured to cover the negative electrode terminal lead 36, and the surface of the negative electrode terminal lead 36 facing the first exterior cover 5 is not short-circuited with the first exterior cover 5. The negative electrode insulating member 33a also has a wall surface facing the second exterior case 6 so that the negative electrode terminal lead 36 does not short-circuit the second exterior case 6.

Fig. 25 shows a perspective view of the negative external terminal 32. As shown in fig. 20 to 25, the negative electrode external terminal 32 includes, for example, a negative electrode head portion 32a and a negative electrode shaft portion in a flat plate shape. The negative electrode shaft portion protrudes from a plane parallel to and on the opposite side of the top surface of the negative electrode head portion 32 a. The negative electrode shaft portion has an elliptical truncated cone or elliptical truncated cylinder first negative electrode shaft portion 32b and an elliptical truncated second negative electrode shaft portion 32c.

Fig. 26 (a) shows a cross-sectional view of the negative electrode external terminal 32 in the short axis direction, and fig. 26 (b) shows a cross-sectional view of the negative electrode external terminal 32 in the long axis direction. In the second embodiment, as in the first embodiment, the length of the minor axis of the top surface of the first negative electrode shaft portion 32b is Ca1, and the length of the major axis of the top surface of the first negative electrode shaft portion 32b is Ca2. The minor axis of the bottom surface of the first negative electrode shaft 32b is designated by Cb1, and the major axis of the bottom surface of the first negative electrode shaft 32b is designated by Cb2. The length of the short axis of the top surface of the second negative electrode shaft 32c is Da1, and the length of the long axis of the top surface of the second negative electrode shaft 32c is Da2. The length of the minor axis of the bottom surface of the second negative electrode shaft portion 32c is Db1, and the length of the major axis of the bottom surface of the second negative electrode shaft portion 32c is Db2. The second embodiment is the same as the first embodiment with respect to the preferable relationship among Ca1, ca2, cb1, cb2, da1, da2, db1, and Db2.

The minor axis direction of the negative electrode external terminal 32 (minor axis direction of the first negative electrode shaft 32b and minor axis direction of the second negative electrode shaft 32 c) and the major axis direction of the negative electrode external terminal 32 (major axis direction of the first negative electrode shaft 32b and major axis direction of the second negative electrode shaft 32 c) are preferably parallel or substantially parallel (within ± 3 degrees of an angular difference) to the outer surface of the first exterior package portion 5 and the bottom surface of the second exterior package portion 6.

In the second embodiment, the cross-sectional shapes of the positive electrode shaft portion and the negative electrode shaft portion are also elliptical, as in the first embodiment. Therefore, the charge/discharge characteristics at a high rate are excellent, and the caulking fixation can be made firm.

Next, a modification of the second embodiment will be described with reference to fig. 27 to 30. The modification of the second embodiment is different from the basic embodiment of the second embodiment in that the first positive electrode shaft portion 17b and the first negative electrode shaft portion 32b are elliptical cylindrical stages. Fig. 27 is a cross section including the center of the positive electrode external terminal 17 and the center of the negative electrode external terminal 32 in the modification. Fig. 28 (a) is a cross-sectional view of a part of the battery obtained when the battery is cut along the plane E-E' in fig. 27. Fig. 28 (b) shows a cross-sectional view of a part of the battery obtained when the battery is cut along the direction of plane F-F' in fig. 27. Fig. 29 is a perspective view of the positive electrode external terminal 17 (negative electrode external terminal 32). Fig. 30 (a) shows a cross-sectional view of the positive electrode external terminal 17 (negative electrode external terminal 32) in the short axis direction, and fig. 30 (b) shows a cross-sectional view of the positive electrode external terminal 17 (negative electrode external terminal 32) in the long axis direction. As shown in fig. 27 to 30, the first positive electrode shaft portion 17b is an elliptical column table, and thus satisfies the relationship of Aa1= Ab1 and Aa2= Ab2. Similarly, on the negative electrode 8 side, the first negative electrode shaft portion 32b has an elliptical cylindrical shape, and therefore satisfies the relationship of Ca1= Cb1 and Ca2= Cb2. By forming the first positive electrode shaft portion 17b and the first negative electrode shaft portion 32b as elliptical columnar pedestals, the shape and the like of the

gaskets

19 and 34 can be simplified, and the yield can be improved. In the modification, it is also preferable to make the cross section of the shaft portion elliptical in order to perform charging and discharging at a high rate.

(third embodiment)

The battery pack of the third embodiment includes one or more batteries of the first embodiment. Fig. 31 and 32 show an example of a battery pack of the battery of the first embodiment.

As shown in fig. 31, the battery pack 300 uses the batteries 100 to 102 of the first embodiment as unit cells. The battery pack 200 is sometimes covered by a laminate not shown. A triangular prism-shaped conductive connecting member 62 is disposed between the distal end surface 32b of the negative external terminal 32 of the first unit cell 60 and the distal end surface 32b of the negative external terminal 32 of the second unit cell 61. Further, a conductive connecting member 62 having a triangular prism shape is disposed between the distal end surface of the positive electrode external terminal 17 of the first unit cell 60 and the distal end surface of the positive electrode external terminal 17 of the second unit cell 61. The two distal end surfaces and the conductive connecting member 62 are electrically connected by welding. Examples of welding include laser welding, arc welding, and resistance welding. This results in cell 63 of the battery module in which first unit cell 60 and second unit cell 61 are connected in parallel. The battery pack 200 is obtained by connecting the cells 63 of the battery assembly in series with each other using the bus bars 64.

The battery pack 201 shown in fig. 32 uses the battery 100 of the first embodiment as a unit cell. A cell in which the first unit cell 60 and the second unit cell 61, which are the batteries 100, are connected in series is used as the cell 65 of the battery module using the conductive connecting member 62, and the cells 65 of the battery module are connected in series with each other via the bus bar 64, thereby constituting a battery pack. The method of electrically connecting the first unit cell 60 and the second unit cell 61 using the conductive connecting member 62 is the same as the method described with reference to fig. 31.

In the battery pack shown in fig. 31 and 32, adjacent first unit cells 60 and second unit cells 61 are stacked with the principal surfaces of the outer jacket material 1 facing each other. For example, in the cell 63 of the battery module shown in fig. 31, the main surface of the first exterior covering 5 of the first unit cell 60 faces the main surface of the first exterior covering 5 of the second unit cell 61. In addition, in the adjacent cell 63 of the battery module, the principal surface of the second exterior cover 6 of the second unit cell 61 of the cell 63 of one battery module faces the principal surface of the second exterior cover 6 of the second unit cell 61 of the cell 63 of the other battery module. By stacking the cells with the main surfaces of the outer jacket material 1 facing each other in this manner, the volumetric energy density of the battery module can be increased.

As shown in fig. 31 and 32, it is preferable that an insulating space is provided between the unit cell 60 and the unit cell 61, or between the

unit cells

60, 60 and the unit cells 61, and a gap of 0.03mm or more can be provided, or an insulating member (for example, polypropylene, polyphenylene sulfide, epoxy, alumina, zirconia, or the like which is a resin, or a fine ceramic) or the like is interposed therebetween.

By providing the positive electrode external terminal 17 and the negative electrode external terminal 32 with truncated pyramid-shaped head portions, the external terminal of the unit cell can be connected to one (first inclined surface) of two portions (for example, first and second inclined surfaces) of one head portion, and the bus bar can be connected to the other (second inclined surface). That is, the connection in both directions can be performed with one head. As a result, the path for electrically connecting the batteries can be shortened, and thus a large current can be easily caused to flow through the battery pack with low resistance.

The assembled battery according to the third embodiment includes at least one battery according to the first embodiment, and therefore, a thin assembled battery having improved flexibility, excellent reliability, and reduced manufacturing cost can be provided.

The battery pack is used as a power source for electronic devices and vehicles (railway vehicles, automobiles, bicycles with prime movers, light vehicles, trolley buses, and the like), for example.

As described above, the battery assembly may include a battery in which a plurality of batteries are electrically connected in series, in parallel, or in a combination of series and parallel. The battery pack may include a circuit such as a battery control unit (BMU) in addition to the battery module, but a circuit included in a device (for example, a vehicle or the like) in which the battery module is mounted may be used as the battery control unit. The battery control unit has a function of monitoring the voltage or current or both of the battery cells and the battery pack to prevent overcharge and overdischarge.

(fourth embodiment)

The battery module of the fourth embodiment has one or more batteries (i.e., single cells) of the above-described embodiments. When a plurality of battery cells are included in the battery module, the battery cells are arranged so as to be electrically connected in series, in parallel, or in series and parallel.

The battery module 400 will be specifically described with reference to the perspective expanded view of fig. 33 and the cross-sectional view of fig. 34. In the battery module 400 shown in fig. 33, the rectangular battery 200 shown in fig. 20 is used as the single cell 401. The sectional view of fig. 34 is a section including the positive electrode external terminal 403B and the negative electrode external terminal 406B of the perspective expanded view of fig. 33.

The plurality of cells 401 have, outside the outer can of the battery, positive electrode external terminals 403 (403A, 403B) provided on a positive electrode gasket 402, a safety valve 404, and negative electrode external terminals 406 (406A, 406B) provided on a negative electrode gasket 405. The cells 401 shown in fig. 33 are arranged so as to be offset from each other. The cells 401 shown in fig. 34 are connected in series, but may be connected in parallel by changing the arrangement method.

The battery cells 401 are housed in the lower case 407 and the upper case 408. The upper case 408 is provided with power input/output terminals 409 and 410 (a positive terminal 409 and a negative terminal 410) of the battery module 400. An opening 411 is provided in the upper case 408 in accordance with the positions of the positive external terminal 403 and the negative external terminal 406 of the cell 401, and the positive external terminal 403 and the negative external terminal 406 are exposed from the opening 411. The exposed positive electrode external terminal 403A is connected to the negative electrode external terminal 406A of the adjacent single cell 401 via the bus bar 412, and the exposed negative electrode external terminal 406A is connected to the positive electrode external terminal 403A of the adjacent single cell 401 on the side opposite to the adjacent side via the bus bar 412. The positive external terminal 403B not connected by the bus bar 412 is connected to a positive terminal 414A provided on the substrate 413, and the positive terminal 414A is connected to the positive power input/output terminal 409 via a circuit on the substrate 413. The negative external terminal 406B not connected by the bus bar 412 is connected to a negative terminal 414B provided on the substrate 413, and the negative terminal 414B is connected to the negative power input/output terminal 410 via a circuit on the substrate 413. The power input/

output terminals

409 and 410 are connected to a charging power source or a load, not shown, for charging or using the battery module 400. The upper housing 408 is sealed by a cover 415. A protection circuit for charging and discharging is preferably provided on the substrate 413. Further, addition of a configuration capable of outputting information such as deterioration of the cell 401 from a terminal not shown may be performed as appropriate. By using the battery 200 of the embodiment, a battery module excellent in charge and discharge characteristics at a high rate can be provided.

(fifth embodiment)

A fifth embodiment relates to an electricity storage device. Battery packs 300 and 301 according to the third embodiment or battery module 400 according to the fourth embodiment can be mounted on power storage device 500. The power storage device 500 shown in the conceptual diagram of fig. 35 includes battery packs 300 and 301, a battery module 400, an inverter 502, and a converter 501. The converter 501 converts dc power from an external ac power source 503 to charge the battery packs 300 and 301 or the battery modules 400, and the inverter 502 converts ac power from the dc power sources of the battery packs 300 and 301 or the battery modules 400 to supply electric power to a load 504 connected to the power storage device 500. By employing the power storage device 500 of the present configuration having the battery packs 300 to 400 of the embodiment, a power storage device having excellent battery characteristics can be provided. In addition, batteries 100 to 200 may be used instead of battery packs 300 and 301 or battery module 400.

(sixth embodiment)

The sixth embodiment relates to a vehicle. The vehicle of the sixth embodiment uses the battery packs 300, 301 of the third embodiment or the battery module 600 of the fourth embodiment. The structure of the vehicle according to the present embodiment will be described in brief with reference to a schematic diagram of the vehicle 600 in fig. 36. The vehicle 600 has battery packs 300, 301 or battery modules 400, a vehicle body 601, a motor 602, wheels 603, and a control unit 604. The battery packs 300 and 301, the battery module 400, the motor 602, the wheels 603, and the control unit &04 are disposed on the vehicle body 601. The control unit 604 converts or adjusts the output of the electric power output from the battery packs 300 and 301 or the battery module 400. The motor 602 rotates the wheels 603 using the electric power output from the battery packs 300, 301 or the battery module 400. The vehicle 600 also includes an electric vehicle such as an electric train, and a hybrid vehicle having another drive source such as an engine. The battery packs 300, 301 or the battery module 400 may also be charged with regenerative energy from the motor 602. The device driven by electric power from the battery packs 300, 301 or the battery module 400 is not limited to the motor 602, and may be used as a power source for operating electric devices included in the vehicle 600. It is preferable that regenerative energy be obtained when the vehicle 600 decelerates, and the battery packs 300 and 301 or the battery module 400 be charged using the obtained regenerative energy. By adopting the vehicle 600 of the present configuration having the battery packs 300, 301 or the battery module 400 of the embodiment, a vehicle having excellent battery characteristics can be provided. In addition, batteries 100 to 200 may be used instead of battery packs 300 and 301 or battery module 400.

(fifth embodiment)

A fifth embodiment relates to a flying body (e.g., a multi-axis helicopter). The battery packs 300 and 301 or the battery module 400 according to the second embodiment are used as the flying object according to the fifth embodiment. The configuration of the flight vehicle according to the present embodiment will be briefly described with reference to a schematic diagram of a flight vehicle (quadcopter) 700 shown in fig. 37. The flight vehicle 700 includes battery packs 300 and 301 or battery module 400, a vehicle body frame 701, a motor 702, a rotor 703, and a control unit 704. The battery packs 300 and 301, the battery module 400, the motor 702, the rotary wing 703, and the control unit 704 are disposed on the body frame 701. The control unit 704 converts or adjusts the output of the electric power output from the battery packs 300 and 301 or the battery module 400. The motor 702 rotates the rotary wing 703 using electric power output from the battery packs 300 and 301 or the battery module 400. By using the flight object 700 of the present configuration including the battery packs 300 and 301 or the battery module 400 of the embodiment, a flight object having excellent battery characteristics can be provided. In addition, batteries 100 to 200 may be used instead of battery packs 300 and 301 or battery module 400.

Several embodiments of the present invention have been described, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Description of the reference numerals

1 outer package member, 2 electrode group, 3 positive electrode terminal portion, 4 negative electrode terminal portion, 5 first outer package portion, 5a opening portion, 5b flange portion, 5c bottom surface, 5d inclined surface, 6 second outer package portion, 7 positive electrode, 7a positive electrode collector tab, 8 negative electrode, 8a negative electrode collector tab, 9 safety valve, 10 electrolyte injection port, 11 backup positive electrode lead, 12 electrode group side positive electrode lead, 13 backup negative electrode lead, 14 electrode group side negative electrode lead, 15, 30 first outer package portion through hole, 16, 31 flanged portion, 17 positive electrode external terminal, 17a positive electrode head portion, 17b first positive electrode shaft portion, 17c second positive electrode shaft portion, 18a positive electrode insulating member, 18b positive electrode reinforcing member, 19, 34 insulating spacer, 20 positive electrode terminal insulating member, 23 positive electrode terminal lead, 24a first positive electrode insulating reinforcing member, 25 a second positive electrode insulating reinforcing member, 26 a positive electrode side internal insulating member, 27 a negative electrode side internal insulating member, 28 opening portion, 32 negative electrode external terminal, 32a negative electrode head portion, 32b first negative electrode shaft portion, 32c second negative electrode shaft portion, 33a negative electrode insulating member, 33b negative electrode reinforcing member, 35 negative electrode terminal insulating member, 36 negative electrode terminal lead, 37a first negative electrode insulating reinforcing member, 38 a second negative electrode insulating reinforcing member, 39 guide hole, 40, 41, 43 welded portion, 42 cut-out portion, 60 a first unit cell, 61 a second unit cell, 62 conductive connecting member, 63, 65 cell assembly unit, 64 bus bar, 100 to 102 cells, 300, 301 cell group, 400 cell group, 401 cell, 402 positive electrode gasket, 403 … positive external terminal, 404 … safety valve, 405 … negative electrode gasket, 406 … negative electrode external terminal, 407 … lower case, 408 … upper case, 409 … power input/output terminal (positive electrode terminal), 410 … power input/output terminal (negative electrode terminal), 411 … opening portion 412, 413 … bus bar, 413 … substrate, 414A 52zxft 526252 positive electrode terminal, 414B 6258 zxft 9658 negative electrode terminal, 415 … cover, 500 … electric storage device, 501 … converter, 502 … inverter, 503 … external alternating current power source, 504 … load, 600 … vehicle, 601 … body, 602 … motor, 603 … wheel, 604 … control unit, 700 … flight body, 701 … body skeleton, 702 … motor, 62703 zxft 6258 rotary wing 704, … control unit.

Claims

1. A battery is provided with: the flat electrode group comprises a positive electrode, a positive electrode collector lug electrically connected with the positive electrode, a negative electrode and a negative electrode collector lug electrically connected with the negative electrode, wherein the positive electrode collector lug wound into a flat shape is positioned on a first end surface, and the negative electrode collector lug wound into a flat shape is positioned on a second end surface; an electrode group-side positive electrode lead electrically connected to the positive electrode collector tab; an electrode group-side negative electrode lead electrically connected to the negative electrode collector tab; an outer package member including a first outer package portion and a second outer package portion, the first outer package portion and the second outer package portion being welded to each other to form a space in which the electrode group is housed; a positive terminal portion in which the first exterior packaging portion has a through-hole on the positive collector tab side, the positive terminal portion including: a positive external terminal including a positive head portion and a positive shaft portion extending from the positive head portion; and a positive electrode terminal lead having a through hole, wherein the positive electrode head protrudes to the outside of the first exterior cover, the positive electrode shaft is inserted into the through hole of the positive electrode terminal lead, and the positive electrode shaft is fixed to the first exterior cover and the positive electrode terminal lead by caulking; and a negative terminal portion in which the first exterior packaging portion has a through-hole on the negative collector tab side, the negative terminal portion including: a negative external terminal including a negative head portion and a negative shaft portion extending from the negative head portion; and a negative electrode terminal lead having a through hole, wherein the negative electrode head portion protrudes outward from the first exterior packaging portion, the negative electrode shaft portion is inserted into the through hole of the negative electrode terminal lead, the negative electrode shaft portion is crimped and fixed to the first exterior packaging portion and the negative electrode terminal lead, the positive electrode shaft portion includes at least a first positive electrode shaft portion of an elliptical truncated cone or an elliptical truncated cylinder and a second positive electrode shaft portion of an elliptical truncated cone, the first positive electrode shaft portion is disposed between the second positive electrode shaft portion and the positive electrode head portion, and a top surface of the first positive electrode shaft portion is directly connected to a top surface of the second positive electrode shaft portion, the negative electrode shaft portion includes at least a first negative electrode shaft portion of an elliptical truncated cone or an elliptical columnar truncated cone and a second negative electrode shaft portion of an elliptical truncated cone, the first negative electrode shaft portion is disposed between the second negative electrode shaft portion and the negative electrode head portion, a top surface of the first negative electrode shaft portion is directly connected to a top surface of the second negative electrode shaft portion, and when a length of a short axis of the top surface of the first positive electrode shaft portion is Aa1 and a length of a long axis is Aa2, a length of the short axis of the top surface of the second positive electrode shaft portion is Ba1 and a length of the long axis is Ba2, a length of the short axis of the bottom surface of the second positive electrode shaft portion is Bb1 and a length of the long axis is Bb2, the following conditions are satisfied: in the case of | (Aa 2-Ba 2) - (Aa 1-Ba 1) | ≦ 0.1mm, and (Bb 2-Ba 2) < (Bb 1-Ba 1), when the length of the minor axis of the top surface of the first negative electrode shaft portion is Ca1, and the length of the major axis is Ca2, and the length of the minor axis of the top surface of the second negative electrode shaft portion is Da1, and the length of the major axis is Da2, and the length of the minor axis of the bottom surface of the second negative electrode shaft portion is Db1, and the length of the major axis is Db2, it is satisfied that: i (Ca 2-Da 2) - (Ca 1-Da 1) I is less than or equal to 0.1mm, and (Db 2-Da 2) < (Db 1-Da 1).

2. The battery according to claim 1, wherein the Aa1 and the Aa2 satisfy: 1.1-Aa 2/Aa 1-2.0, said Ca1 and said Ca2 satisfying: ca2/Ca1 is more than or equal to 1.1 and less than or equal to 2.0.

3. The battery according to claim 1 or 2, wherein the Aa2 and the Ba2 satisfy: 1.05 ≦ Aa2/Ba2 ≦ 1.5, the Ca2 and the Da2 satisfying: ca2/Da2 is more than or equal to 1.05 and less than or equal to 1.5.

4. The battery according to claim 1 or 2, wherein the bottom surface of the first positive electrode shaft portion is a surface facing the positive electrode head portion, the top surface of the first positive electrode shaft portion is a surface on the opposite side of the bottom surface of the first positive electrode shaft portion, the top surface of the second positive electrode shaft portion is a surface facing the positive electrode head portion, the bottom surface of the second positive electrode shaft portion is a surface on the opposite side of the top surface of the second positive electrode shaft portion, the bottom surface of the first negative electrode shaft portion is a surface facing the negative electrode head portion, the top surface of the first negative electrode shaft portion is a surface on the opposite side of the bottom surface of the first negative electrode shaft portion, the top surface of the second negative electrode shaft portion is a surface facing the negative electrode head portion, and the bottom surface of the second negative electrode shaft portion is a surface on the opposite side of the top surface of the second negative electrode shaft portion.

5. The battery of claim 1 or 2, wherein the positive shaft portion is solid and the negative shaft portion is solid.

6. The battery according to claim 1 or 2, wherein the second positive electrode shaft portion is fixed by caulking to the positive electrode terminal lead, at least a part or all of an inner wall of the through hole of the positive electrode terminal lead is welded to the second positive electrode shaft portion, the second negative electrode shaft portion is fixed by caulking to the negative electrode terminal lead, and at least a part or all of an inner wall of the through hole of the negative electrode terminal lead is welded to the second negative electrode shaft portion.

7. The battery according to claim 1 or 2, wherein the Ba1, the Ba2, the Bb1, and the Bb2 satisfy: 1.2 (Bb 2-Ba 2) < (Bb 1-Ba 1), the Da1, the Da2, the Db1, and the Db2 satisfy: 1.2 (Db 2-Da 2) < (Db 1-Da 1).

8. The battery according to claim 1 or 2, wherein when Ab1 is a short axis length of the bottom surface of the first positive electrode shaft portion, and Ab2 is a long axis length, the following is satisfied: 1.08. Ltoreq. Ab2/Ab 1. Ltoreq.2.0, and Cb1 is a length of a minor axis and Cb2 is a length of a major axis of the bottom surface of the first negative electrode shaft portion, the following are satisfied: cb2/Cb1 is more than or equal to 1.08 and less than or equal to 2.0.

9. A battery comprising one or more cells of any one of claims 1 to 8.

10. A battery module comprising one or more batteries of any one of claims 1 to 8.

11. An electricity storage device comprising the battery according to any one of claims 1 to 8, the battery pack according to claim 9, or the battery module according to claim 10.

12. A vehicle comprising the battery of any one of claims 1 to 8, the battery pack of claim 9, or the battery module of claim 10.

13. A flying object comprising the battery of any one of claims 1 to 8, the battery pack of claim 9, or the battery module of claim 10.