JPH08329958A - Spiral type non-aqueous electrolyte battery and method for winding spiral electrode body - Google Patents

Abstract

PURPOSE: To make high speed automatic assembly of a battery possible by constituting a spiral nonaqueous electrolyte battery with a metal negative can, each specified spiral electrode body, and an insulating member. CONSTITUTION: A nonaqueous electrolyte battery is constituted with a metal negative can 1, a spiral electrode body 2 formed by spirally winding a negative plate 3 and a positive plate 4 through a separator 5 around a synthetic resin or a stainless steel core 9 having a C-shaped cross section in which a longitudinal cut part 8 is formed along the whole length in the larger direction, and an insulating member 7 arranged between the inner bottom surface of the negative can 1 and the bottom surface of the spiral electrode body 2. Preferably, a through hole 9a is formed in the core 9. The insulating member 7 is preferable to be a framed short cylindrical molding integrally molded with a cylinder part 7b capable of fitting to the inside of the core 9 on the one side of a circular disk part 7a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral type non-aqueous electrolyte battery in which a spirally wound electrode body is arranged in a metal negative electrode can and a method for winding the spirally wound electrode body.

[0002]

2. Description of the Related Art A spiral type non-aqueous electrolyte battery such as a lithium battery of this type has a spiral structure in which a positive electrode plate and a negative electrode plate are superposed and wound in a metal negative electrode can via a separator. A cylindrical electrode body is disposed, and a hollow cylindrical portion that is inserted into a hole formed in the center of the winding is attached to one side of the cylindrical electrode body,
In addition, there has been conventionally known a structure in which an insulating member having a projecting piece capped in a central void portion of a spirally-wound electrode body is arranged at a peripheral portion thereof (Japanese Utility Model Publication No. 4-212249).

The method of winding the spirally wound electrode body is roughly classified into two, one of which is, for example, coating both side surfaces of the negative electrode plate with separators, and rotating the winding machine at the ends of the cover body. After inserting it into the groove formed on the shaft, rotate it about 1 turn,
Next, add a positive electrode plate to this and wind it together.
1-7133). The other is to insert the extended end of the separator into a vertical groove formed in the rotary shaft of the winding machine and sandwich it, and after rotating the extended part of the separator about 1 turn, Then, the positive electrode plate is attached to this and wound together, and after the winding is completed, the wound body is removed from the rotary shaft (JP-A-62-147661).

In addition, by disposing a rod-shaped insulator provided with a gas vent hole in the central cavity of the spiral electrode body, an internal short circuit due to an increase in the volume of the electrode body is prevented, and the electrolytic solution is usually used. Proposal to prevent the electrolyte from overflowing by the rod-shaped insulator inserted after the injection (Actual Kaihei 1-155)
No. 262). In this publication, a winding core that serves as a winding rod when a winding body is manufactured is made of an insulating material, and after winding a predetermined number of times, the winding core is made into the insulating material and the winding material. It is described that they may be cut together and then housed in an outer can and sealed by a lid attached by caulking via a gasket.

[0005]

Since the electrode plate inserted into the groove of the rotary shaft is bent at a substantially right angle, the electrode plate portion may be collapsed. Further, since the separator extension portion inserted in the vertical groove of the rotary shaft remains in a square shape in the central void portion of the spiral electrode body, an electrode for spot welding is formed in the center portion of the spiral electrode body. When inserting and connecting the metal negative electrode can and the negative electrode lead plate, it had to be manually corrected so that the square-shaped separator portion was aligned with the inner surface of the central cavity. Furthermore, in the prior art, even if the spirally wound electrode body is inserted into the negative electrode can, the center positioning reference is maintained even when the group presser is inserted subsequently, the spot welding electrode rod is inserted, and further, the electrolytic solution is injected. Since it was unstable or difficult to remove, it was a major obstacle in achieving high-speed automatic assembly of the spiral type non-aqueous electrolyte battery.

Therefore, an object of the present invention is to provide a structure of a novel spiral type non-aqueous electrolyte battery which enables high-speed automatic assembly and a winding method of the spiral electrode body.

[0007]

In order to achieve the above object, a spiral non-aqueous electrolyte battery according to the present invention has a vertical notch formed in a metal negative electrode can over the entire length in the longitudinal direction. A synthetic resin or stainless steel core having a C-shaped cross section, and a spirally wound electrode body formed by winding a negative electrode plate and a positive electrode plate around the core in a laminated manner with a separator interposed therebetween.
An insulating member that separates the bottom surface of the negative electrode can from the lower surface of the spiral electrode body is provided.

A through hole may be formed in the core.

The above-mentioned insulating member is a flanged short cylinder molded product integrally formed with a tubular portion which can be fitted inside the core on one side of an annular disc portion, or is fitted to the outer peripheral portion of the lower end of the core. It may be an annular disc that can be used, or a brim-shaped plate integrally formed at the lower end of the core with an obtuse angle with respect to the axis of the core.

Further, a metal negative electrode can and a core made of synthetic resin or stainless steel having a C-shaped cross section, which is housed in the negative electrode can and formed with a vertical cutout along the entire length in the longitudinal direction, are used as cores. A spirally wound electrode body in which a negative electrode plate and a positive electrode plate are wound in a laminated manner via a separator, and is disposed between the inner bottom surface of the negative electrode can and the bottom surface of the spirally wound electrode body, and has a cutout portion. A spiral type non-aqueous electrolyte battery comprising an annular insulating member, wherein an insulating tape is attached to a negative electrode lead plate connected to the negative electrode plate of the spirally wound electrode body, and a cutout of the insulating member is formed with this insulating tape. It is designed to close the part.

Further, a metal negative electrode can and a core made of synthetic resin or stainless steel having a C-shaped cross section, which is housed in the negative electrode can and has a vertical notch formed over the entire length in the longitudinal direction, are used as cores. A spiral electrode body in which a negative electrode plate and a positive electrode plate are wound in a laminated manner with a separator interposed therebetween, and is disposed between the inner bottom surface of the negative electrode can and the bottom surface of the spiral electrode body, and integrated with the core. A spiral non-aqueous electrolyte battery comprising a formed annular insulating member, wherein the insulating member is provided with a thin portion connected to the vertical cutout portion of the core, and a radial notch is formed in this thin portion. It is a thing.

The spiral electrode body winding method according to the present invention has a cross-section C in which a vertical notch is formed over the entire length in the longitudinal direction.
A synthetic resin or stainless steel core having a shape is inserted into, for example, a rotary shaft with a key of a winding machine, and a vertical cutout portion of the core is engaged and locked with a key of the rotary shaft of the winding machine. The extending end portion of the separator that covers both side surfaces of either the negative electrode plate or the positive electrode plate is fixed to the outer surface of the core.
Alternatively, a synthetic resin or stainless steel core having a C-shaped cross section with a longitudinal cutout formed over the entire length in the longitudinal direction is pushed in from the outside of, for example, a rotary shaft with a key of a winding machine to fit the core into the longitudinal direction of the core. The cutout portion and the key of the rotating shaft of the winding machine are engaged and locked, and the extending end portion of the separator that covers both side surfaces of one of the negative electrode plate and the positive electrode plate is provided with the core and the core. Hold it between the rotating shafts. After that, in each case, the separator extending portion is wound, then the other electrode plate is attached and wound together, and after the winding work is completed, the wound body including the core is removed from the rotating shaft.

The rotating force for forming the spirally wound electrode body on the outer side of the core is obtained by engaging a key provided on the rotating shaft of the winding machine with a vertical notch formed over the entire length of the core in the longitudinal direction. Securely obtained by locking. This core is a high-speed spiral type non-aqueous electrolyte battery in which the spiral electrode body is inserted into the negative electrode can, the group presser is inserted, the spot welding electrode rod is inserted, and further the electrolyte injection pipe is inserted. It can be used as a reliable center positioning reference in the automatic assembly process.

If the insulating member that separates the inner bottom surface of the negative electrode can from the lower surface of the spirally wound electrode body is formed separately from the core, there is no obstacle when the spirally wound electrode body is formed outside the core. It can be performed in the absence of the core, and the core and the insulating member can be fitted and integrated after winding. Further, in the structure in which the collar-shaped plate corresponding to the insulating member is integrally formed at the lower end of the core with an obtuse angle with respect to the axis of the core, the winding body escapes so as not to hit the collar-shaped plate. Therefore, the winding can be smoothly performed to the end, and it is not necessary to integrate the wound core with the insulating member.

If the core has a through hole, when the electrolyte is injected,
The electrolytic solution, which is about to enter from the central portion of the core, can pass through the through hole and permeate into the spiral electrode body.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a spiral lithium battery will be described below.

In FIG. 1, in the negative electrode can 1 made of metal,
A core 9 made of synthetic resin or stainless steel and having a C-shaped cross section with a longitudinal cutout 8 formed along the entire length in the longitudinal direction serves as a winding core, and the spiral electrode body 2 is arranged outside the core 9. ing. The spiral electrode body 2 is a wound body in which a negative electrode plate 3 made of lithium and a positive electrode plate 4 having manganese dioxide as an active material are polymerized by alternately interposing a separator 5 made of polypropylene nonwoven fabric, and It is the same as the conventional one in that the insulating member 7 disposed between the inner bottom surface of the negative electrode can 1 and the lower surface of the spirally wound electrode body 2 isolates the both. The insulating member 7 shown in the figure is a flanged short cylinder molded product integrally formed with a tubular portion 7b which can be fitted inside the core 9 on one side of the annular disc portion 7a, and is a flat annular disc. The negative electrode lead plate 6 is pressed against the inner bottom surface of the negative electrode can 1 at the portion 7a. In the figure, 11 is a positive electrode terminal electrically connected to the positive electrode lead plate 10, 12 is a group retainer, and 13 is a group fixing tape adhered so that the wound spirally wound electrode body 2 does not come apart. Is.

In order to obtain the above-described core 9 having the vertical notch 8 formed over the entire length in the longitudinal direction as a warp-free molded product, as shown in FIG. 6, the built-up portion 1 is formed inside the end face of the vertical notch 8.
It is good to form and balance 4,14. Insulation member 7
In addition to the collared short cylinder molded product of Fig. 1, as shown in Fig. 2,
It may be an annular disc 7c having a hole 15 into which the lower end of the core 9 can be fitted. As described above, when the core 9 and the insulating member 7 are separated from each other, a fitting process is required, but when the spirally wound electrode body 2 is wound around the core 9, the winding is performed without any obstacles. You can turn it. Contrary to this, if a collar-shaped plate is integrally formed at one end of the core 9 at a right angle, even if the above-described step of fitting the core 9 and the insulating member 7 can be omitted, when the separator 5 is first fixed to the core 9. If it is not done so strictly, the wound product may gradually become closer to the flange plate side during the winding, and the winding may become impossible.

In order to avoid such inconvenience, as in the other embodiment shown in FIG. 3, the core 9 is provided at the lower end of the core 9.
By integrally forming the collar-shaped plate 7d so as to form an obtuse angle with respect to the axis of the separator, a clearance is provided so that the separator 5 does not hit the collar-shaped plate 7d and cannot be wound.

The method of forming the spiral electrode body 2 including the core 9 by winding will be described below.
One of them is that the material of the core 9 is such that it can be fused with the separator 5, and as shown in FIG. 4, it is made of a synthetic resin having a C-shaped cross section in which a vertical notch 8 is formed over the entire length in the longitudinal direction. A key 17 of a winding machine (not shown) for the core 9 made of stainless steel.
It is inserted into the attached rotary shaft 16, and the vertical cutout portion 8 of the core 9 and the key 17 of the rotary shaft 16 of the winding machine are engaged and locked. On the outer surface of the core 9, the extended end portion of the separator 5 which covers both side surfaces of one of the negative electrode plate 3 and the positive electrode plate 4 is directly fixed by an adhesive means such as ultrasonic fusion (reference numeral). 1
8 indicates a fusion-bonded portion), and then the separator extending portion is wound about one rotation, and then another electrode plate is attached to this to start winding together, and after the winding work is completed. Removes the spiral electrode body 2 which is a wound body including the core 9 from the rotating shaft 16. In this case, the outer surface of the key 17 of the rotary shaft 16 is
As shown by the two-dot chain line, if it is constituted by an arc that is substantially on the same circle as the outer surface of the core 9, the obtained spiral electrode body 2 will not have a distorted portion.

As another winding method, as shown in FIG. 5, the width of the vertical notch 8 formed along the entire length of the core 9 in the longitudinal direction is set to an appropriate value (for example, winding). If the diameter of the rotary shaft 16 of the rotating machine is 3.4 mm, the width of the vertical cutout 8 of the core 9 is about 2 mm), and the core 9 is pushed in from the outside of the rotary shaft 16 as indicated by the arrow. Let me hold you. At this time, the vertical notch 8 of the core 9 is engaged and locked with, for example, the key 17 of the winding shaft 16 of the winding machine, and at the same time, the extended end of the separator 5 is connected to the core 9 and the rotating shaft 16 of the winding machine. It will be pinched and fixed between them. Winding is started after the pinching, and after the winding work is completed, the spiral electrode body 2, which is a wound body including the core 9, is removed from the rotary shaft 16 in the same manner as in the insertion method described above.

When the core 9 shown in FIG. 3 and the collar plate 7d are integrally formed, the rotary shaft 1 is used when this winding method is used.
The collar-shaped plate 7d so that the core 9 can be pushed in from the outside of 6
It is necessary to form a cutout portion 19 connected to the vertical cutout portion 8 of the core 9 on the core 9, but as shown in FIG.
If the 9 is formed in a V shape, the core 9 can be easily expanded when it is pushed in from the outside of the rotary shaft 16. At this time, as shown in FIG. 11, an insulating tape 22 is attached to the negative electrode lead plate 6, and the notch 19 of the insulating member 7 is closed with this insulating tape 22 to form the spiral electrode body 2 after the battery is assembled. Negative electrode can 1
It is possible to prevent the occurrence of a situation in which the and are brought into contact with each other to cause an internal short circuit. Further, the engagement and locking may be performed only by the clamping force of the core 9. Further, as shown in FIG. 12, if a thin portion 20 is provided in the insulating member 7 and a radial notch 21 is formed in the center thereof, the core 9 can be pushed in from the outside of the rotary shaft 16 and, at the same time, the negative electrode It is possible to prevent an internal short circuit without attaching the insulating tape 22 to the lead plate 6 and insulating it.

As shown in FIGS. 7 to 9, the core 9
By forming a plurality of through-holes 9a in the core, it is possible to facilitate the permeation of the electrolytic solution from the inside to the outside of the core 9 during the injection of the electrolytic solution, and to shorten the injection time of the electrolytic solution. Also,
As shown in FIG. 10, the same applies to the case where the through hole 9a is formed in the core 9 integrally formed with the insulating member 7. Actually, when a core 9 having a through hole 9a formed therein (type shown in FIG. 7) and a core 9 having no through hole 9a were prepared and the permeability of the electrolytic solution was compared, the former showed a higher electrolytic solution than the latter. The liquid injection time was about half.

[0024]

As is apparent from the above description, according to the present invention, the core of synthetic resin or stainless steel having a C-shaped cross section is disposed at the center of the spiral electrode body. When performing high-speed automatic assembly of a spiral type non-aqueous electrolyte battery in which each step such as insertion into the negative electrode can, insertion of a group presser, insertion of an electrode rod for spot welding, and insertion of an electrolyte injection pipe is performed, The core can be used as a solid centering reference. The vertical notch formed over the entire length in the longitudinal direction of the core has the function of engaging and locking the rotation shaft of the winding machine to rotate the core, and also provides the expansion required in the case of the pinching method described later. It is possible.

If the insulating member is a brim-shaped short cylinder molded product, the core and the insulating member are surely integrated by fitting the cylindrical portion inside the core. Molding is easy in the case of an annular disc that can be fitted to the outer periphery of the lower end of the core. Further, in the one in which the flange-shaped plate forming an obtuse angle with the axis of the core is integrally formed at the lower end portion of the core, the wound product does not hit the flange-shaped plate so as not to be wound, and By removing the wound object from the rotary shaft of the winding machine by grasping the flange-shaped plate away from it, stress on the end face of the wound body can be eliminated, and after assembly, anti-backlash in the thrust direction or buffer spring function can be expected. You can

If the through hole is formed in the core, the electrolytic solution that is about to enter from the center of the core when the electrolytic solution is injected passes through the through hole and permeates into the spiral electrode body. The time for injecting the electrolyte solution can be shortened. In addition, the degree of warpage is reduced and the dimensional accuracy is improved, which contributes to improved productivity.

If an insulating tape is attached to the negative electrode lead plate and the notch of the insulating member is closed with this insulating tape, the spiral electrode body and the negative electrode can come into contact with each other after the battery is assembled, causing an internal short circuit. There is no such thing.

If a thin-walled portion is provided on the annular insulating member and a radial cut is made in this thin-walled portion, the inner portion is formed even if the negative electrode lead plate is not insulated even though the insulating member is integrally formed with the core. It is possible to prevent a short circuit.

Next, the effect of the winding method of the present invention will be described. In the insertion method in which the rotary shaft of the winding machine is inserted into the core, the vertical notch of the core is a key that cooperates with the key of the rotary shaft of the winding machine. Since the groove can have a relatively narrow width, it is possible to reduce the degree of diameter reduction of the core that is received by the tightening force of the winding material wound on the outside of the core, which is very convenient when using the core as a reference during assembly. is there. There is no particular problem in terms of the influence on the expansion and contraction of the separator due to fusion and the reliability of adhesion.

Further, in the sandwiching method of covering the rotating shaft of the winding machine with the core, the extension end of the separator is fixed to the core, which is advantageous in that the sandwiching can be simply carried out. The width of the vertical notch is slightly larger to allow the core to expand, and the degree of core reduction caused by the tightening force of the wound material is also somewhat large, but that can be used as a reference when assembling the core. There is nothing to lose.

In any of the winding methods, since the spirally wound electrode body, which is a wound body, contacts the rotating shaft through the core, the spirally wound electrode body, which is a wound body including the core, is wound after the winding work is completed. When removing the body from the rotating shaft, there is no possibility of dragging the wound body into a bamboo shape as in the conventional case.

[Brief description of drawings]

1A is a sectional view showing a first embodiment of a spiral-type non-aqueous electrolyte battery according to the present invention, and FIG. 1B is an enlarged sectional view showing a state of a winding core portion of FIG. 1A. .

FIG. 2 is a sectional view showing a main part of a second embodiment.

FIG. 3 is a sectional view showing a main part of a third embodiment.

FIG. 4 is a perspective view illustrating a winding method of the spiral electrode body according to the present invention.

FIG. 5 is a perspective view illustrating another winding method of the spiral electrode body according to the present invention.

FIG. 6 is a cross-sectional view of a core provided with a collar plate.

FIG. 7 is a perspective view showing an example of a core having through holes formed therein.

FIG. 8 is a perspective view showing another example of a core having a through hole formed therein.

FIG. 9 is a perspective view showing still another example of a core having a through hole formed therein.

FIG. 10 is a perspective view showing still another example of a core having a through hole formed therein.

FIG. 11 is a perspective view showing a spiral electrode body arranged on a core.

FIG. 12 is a perspective view showing an example of a core in which a thin portion is provided on an insulating member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Negative electrode can, 2 ... Spiral electrode body, 3 ... Negative electrode plate, 4 ... Positive electrode plate, 5 ... Separator, 6 ... Negative electrode lead plate, 7 ... Insulating member, 7a ... Annular disk part, 7b ... Cylindrical part, 7c ... annular disc,
Reference numeral 7d ... Collar plate, 8 ... Vertical notch, 9 ... Core, 9a ... Through hole, 10 ... Positive lead plate, 11 ... Positive terminal, 12 ... Group retainer, 13 ... Group fixing tape, 14 ... Padding section, 15 ... holes,
16 ... Rotating shaft, 17 ... Key, 18 ... Fusion-bonded part, 19 ... Notch part, 20 ... Thin part, 21 ... Notch, 22 ... Insulating tape

Front page continuation (72) Inventor Tomoya Murata 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. (72) Keiji Fukuhara 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. In-company (72) Inventor Massei Kato 5-36-1 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. (72) Inventor Masakazu Kitakata 5-36-11 Shinbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. Within

Claims (9)

[Claims] 1. A negative electrode can (1) made of metal, and a synthetic resin or stainless steel having a C-shaped cross section, which is housed in the negative electrode can and has a vertical notch (8) formed along the entire length in the longitudinal direction. Of the spirally wound electrode body (2) in which the negative electrode plate (3) and the positive electrode plate (4) are wound in a laminated manner with the core (9) of FIG. A spiral type non-aqueous electrolyte battery comprising an insulating member (7) disposed between the inner bottom surface and the bottom surface of the spiral electrode body. 2. The spiral type non-aqueous electrolyte battery according to claim 1, wherein a through hole (9a) is formed in the core (9). 3. The insulating member (7) comprises an annular disc portion (7).
3. A flanged short cylinder molded product integrally formed with a cylinder part (7b) which can be fitted inside the core (9) on one side of a). The spiral type non-aqueous electrolyte battery described. 4. The insulating member (7) comprises the core (9).
An annular disc (7) that can be fitted to the outer periphery of the lower end of the
The spiral non-aqueous electrolyte battery according to claim 1 or 2, which is c). 5. The insulating member (7) comprises the core (9).
The spiral non-aqueous electrolyte according to claim 1 or 2, characterized in that it is a flange-shaped plate (7d) integrally formed at the lower end of the core so as to form an obtuse angle with the axis of the core. battery. 6. A negative electrode can (1) made of metal, and made of synthetic resin or stainless steel having a C-shaped cross section, which is housed in the negative electrode can and has a vertical notch (8) formed along the entire length in the longitudinal direction. Of the spirally wound electrode body (2) in which the negative electrode plate (3) and the positive electrode plate (4) are wound in a laminated manner with the core (9) of FIG. A spiral type non-aqueous electrolyte battery, which is arranged between an inner bottom surface and a bottom surface of a spiral electrode body and comprises an annular insulating member (7) having a notch (19), wherein the spiral electrode body Insulating tape (22) is attached to the negative electrode lead plate (6) connected to the negative electrode plate of (1), and the notch of the insulating member is closed with this insulating tape. battery. 7. A negative electrode can (1) made of metal and a synthetic resin or stainless steel having a C-shaped cross section, which is housed in the negative electrode can and has a vertical cutout (8) formed along the entire length in the longitudinal direction. Of the spirally wound electrode body (2) in which the negative electrode plate (3) and the positive electrode plate (4) are wound in a laminated manner with the core (9) of FIG. A spiral non-aqueous electrolyte battery comprising an annular insulating member (7) disposed between an inner bottom surface and a bottom surface of a spiral electrode body and integrally formed with the core, wherein: A thin portion (20) connected to the vertical cutout portion of the core is provided, and a radial notch (2) is formed in this thin portion.
A spiral type non-aqueous electrolyte battery containing 1). 8. A rotary shaft with a key (17) of a winding machine, which comprises a core (9) made of synthetic resin or stainless steel and having a C-shaped cross section in which a vertical notch (8) is formed over the entire length in the longitudinal direction. 16)
The core of the winding shaft and the key of the rotary shaft of the winding machine are engaged with each other, and the outer surface of the core is provided with either the negative electrode plate (3) or the positive electrode plate (4). After fixing the extending end of the separator (5) covering both side surfaces of the electrode plate, winding the separator extending part, and then winding the electrode plate together with another electrode plate, and ending the winding operation. After that, the spirally wound electrode body is wound by removing the wound body including the core from the rotary shaft. 9. A rotary shaft with a key (17) of a winding machine, which comprises a core (9) made of synthetic resin or stainless steel and having a C-shaped cross section in which a vertical notch (8) is formed over the entire length in the longitudinal direction. 16)
Of the negative electrode plate (3) or the positive electrode plate (4) while the vertical cutout portion of the core and the key of the rotating shaft of the winding machine are engaged and locked by pushing from the outside of the After sandwiching the extending end portion of the separator (5) covering both side surfaces of the plate between the core and the rotating shaft, the separator extending portion is wound, and then another electrode plate is attached together. A spiral-type electrode body winding method comprising: winding a spirally wound electrode body, and removing a winding body including a core from the rotating shaft after the winding work is completed.