JP2008108742A - Lithium ion battery and manufacturing method thereof - Google Patents

Abstract

Provided is a lithium ion battery that eliminates the need for a current collecting lead and has desired battery performance.
A positive electrode plate 18 is provided with a non-applied portion 24 at one end in the width direction and a positive electrode active material 26 is applied. A negative electrode plate 20 is provided with an unapplied portion 28 at the other end in the width direction. 30 is applied. The uncoated portions 24 and 28 protrude in opposite directions, and the positive electrode active material 26 and the negative electrode active material 30 are arranged to face each other and substantially coincide with each other in the width direction.
[Selection] Figure 4

Description

  The present invention relates to a lithium ion battery configured by housing a plate group in which a strip-like positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween in a battery can, and a manufacturing method thereof.

  In general, in the battery assembly process, after an electrode plate group is formed by winding a strip-shaped positive electrode plate and a negative electrode plate with a separator interposed therebetween, the electrode plate group is housed in a battery can, An operation of injecting an electrolytic solution into the battery can is performed.

  The positive electrode plate and the negative electrode plate are usually prepared by intermittently applying an active material to a strip-shaped current collector at a pitch of one battery in the longitudinal direction. Then, in the winding machine, in order to prevent the pitch error of the active material from accumulating, the uncoated portion of the active material is detected each time, the current collecting lead is welded, the protective tape (insulating tape) is applied, and the winding is performed. Troublesome work such as times is performed. For this reason, in the winding machine, a considerable time is required for the detection and adjustment work of the uncoated portion, and there is a problem that the productivity of the original winding work is significantly reduced.

  Further, since the current collecting lead is welded to each of the positive electrode plate and the negative electrode plate, the winding operation is stopped when the current collecting lead is used as a roll body and is switched to the rewinding shaft, and the productivity is reduced. It will be triggered. Moreover, since the cross-sectional area of the current collecting lead is small, there is a problem that the internal resistance of the battery increases.

  Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 56-45567, upper and lower electrodes of a spiral electrode body in which a strip-like positive electrode and a negative electrode are shifted in the vertical direction and wound with a separator interposed therebetween. A current collector made of a metal plain plate that is integrally provided with an extension that forms a lead piece is disposed on each protruding end, and after welding the current collector and the electrode protruding end by ultrasonic welding, Manufacturing methods for batteries to be incorporated are known.

  By the way, in the above prior art, since the positive electrode and the negative electrode are wound in a state shifted from each other in the vertical direction, the positive electrode active material applied to the positive electrode and the negative electrode active material applied to the negative electrode are arranged in the width direction. It will be displaced. However, particularly in a lithium ion battery, if the positive electrode active material and the negative electrode active material are shifted from each other in the width direction, a local defect is likely to occur in the battery reaction, and a lithium ion battery having desired performance cannot be obtained. Has been pointed out.

  The present invention solves this type of problem, and provides a lithium ion battery having a desired battery performance and a method of manufacturing the lithium ion battery that enable efficient battery manufacturing work without requiring a current collecting lead. The purpose is to do.

  In order to solve the above problems, in the lithium ion battery and the manufacturing method thereof according to the present invention, an uncoated portion is provided on one end side in the width direction of the positive electrode plate, and an uncoated portion is disposed on the other end side in the width direction of the negative electrode plate. Each uncoated portion is welded to the positive electrode current collector plate and the bottom of the battery can or the negative electrode current collector plate as a current collector.

  At that time, the positive electrode active material and the negative electrode active material are arranged so as to face each other and substantially coincide with each other in the width direction. As a result, the manufacturing work of the lithium ion battery is efficiently performed without the need for a current collecting lead, and the productivity can be easily improved. In addition, since the positive electrode active material and the negative electrode active material do not shift in the width direction, it is possible to easily and reliably manufacture a lithium ion battery having desired performance.

  As described above, in the lithium ion battery and the manufacturing method thereof according to the present invention, the uncoated portions of the positive electrode plate and the negative electrode plate constituting the electrode plate group protrude in different directions, and the positive electrode activity of the positive electrode plate is increased. The material and the negative electrode active material of the negative electrode plate are disposed so as to face each other and substantially coincide with each other in the width direction. This eliminates the need for a current collecting lead, and does not cause local defects in the battery reaction due to the displacement of the positive electrode active material and the negative electrode active material in the width direction. It becomes possible to manufacture a lithium ion battery easily and efficiently.

  FIG. 1 is a longitudinal sectional explanatory view of a lithium ion battery 10 according to an embodiment of the present invention, and FIG. 2 is an enlarged longitudinal sectional explanatory view of a main part of the lithium ion battery 10.

  The lithium ion battery 10 includes a battery can 12 having a bottomed cylindrical shape, and an electrode plate group 16 enclosed in the battery can 12 together with an electrolytic solution (not shown). The electrode plate group 16 is configured by winding the positive electrode plate 18 and the negative electrode plate 20 with separators 22a and 22b interposed therebetween.

  As shown in FIGS. 3 and 4, the positive electrode plate 18 has a length corresponding to one battery in the longitudinal direction (arrow A direction), and its width direction (arrow B direction) upper end side (one end side). The positive electrode active material 26 is applied with an uncoated portion 24 provided thereon. Similarly, the negative electrode plate 20 has a length corresponding to one battery in the longitudinal direction, and the negative electrode active material 30 is applied with an uncoated portion 28 provided on the lower end side (the other end side) in the width direction. The width direction length H1 of the negative electrode active material 30 is set to be larger than the width direction length H2 of the positive electrode active material 26. The width direction length H3 of the separators 22a and 22b interposed between the positive electrode plate 18 and the negative electrode plate 20 to insulate them is set to have a relationship of H3> H1 (> H2).

  The electrode plate group 16 is fastened by a tape 32 (see FIG. 1), and a positive electrode current collector plate 34 is welded to an uncoated portion 24 of the positive electrode plate 18 protruding upward, and protrudes downward therefrom. The negative electrode current collector plate 36 is welded to the uncoated portion 28 of the negative electrode plate 20.

  The battery can 12 has an opening 38 at one end thereof, and an annular groove 40 is formed in the vicinity of the opening 38. A sealing component 42 is fixed to the opening 38, and the sealing component 42 and the positive electrode current collector plate 34 are electrically connected via a conductive plate 44. An insulating plate 45 is disposed on the positive electrode current collector plate 34. The negative electrode current collector plate 36 is welded to the inner bottom 46 of the battery can 12. Instead of using the negative electrode current collector plate 36, the uncoated portion 28 of the negative electrode plate 20 may be directly welded to the inner bottom portion 46 of the battery can 12.

  A method for manufacturing the lithium ion battery 10 configured as described above will be described below.

  In this embodiment, as shown in FIG. 5, it has active material application | coating process S1, slit process S2, winding process S3, and assembly process S4. In the active material coating step S1, as shown in FIGS. 5A and 6, the positive electrode current collector 50 is unwound from the roll, and coating machines 52a, 52b, and 52c are disposed on the way of unwinding. . The applicators 52a to 52c are spaced apart by an interval corresponding to the width dimension of the uncoated part 24 of the positive electrode plate 18, and the respective application widths are set to the width dimension of the positive electrode active material 26 of the positive electrode plate 18.

  Therefore, while the positive electrode current collector 50 is unwound from the roll and is again wound on the roll, the three positive electrode active materials 26 are sandwiched between the unapplied portions 24 in the width direction under the action of the applicators 52a to 52c. It is applied in a wet state. Next, as shown in FIG. 5B and FIG. 7, in the slitting step S <b> 2, the positive electrode current collector 50 in which the positive electrode active material 26 is formed in stripes in the longitudinal direction and three strips in the width direction is It is slit through slitters 54a, 54b and 54c while being rewound.

  In this slitting step S2, positive electrode current collectors 50a to 50c each having an uncoated portion 24 on one end in the width direction are obtained via slitters 54a to 54c, and the positive electrode current collectors 50a to 50c are respectively wound in a roll shape. Turned. Further, each of the positive electrode current collectors 50a to 50c is cut for each length of one battery to form the positive electrode plate 18 (FIG. 5C).

  On the other hand, as shown in FIG. 5 (d), the strip-shaped negative electrode current collector 56 has three strips of the negative electrode active material 30 in the width direction via the applicators 58 a, 58 b and 58 c, similarly to the positive electrode current collector 50. Are formed in a stripe shape in the longitudinal direction, and an uncoated portion 28 set to a predetermined width dimension is provided. Next, as shown in FIG. 5E, the negative electrode current collector 56 is slit through slitters 60a, 60b and 60c spaced apart by a predetermined distance, and the negative electrode current collector having an uncoated portion 28 on the other end in the width direction. The bodies 56a, 56b and 56c are obtained. The negative electrode current collectors 56a to 56c are cut for each length corresponding to one battery to form the negative electrode plate 20 (FIG. 5 (f)). Note that metallic lithium 62 set to a predetermined width dimension is attached to the negative electrode plate 20.

  Next, in the winding step S3, the separator 22a, the negative electrode plate 20, the separator 22b, and the positive electrode plate 18 are wound in an overlapping state from the lower side to form the electrode plate group 16, and the winding end is formed by the tape 32. It is curled up. At that time, as shown in FIGS. 4 and 5G, the uncoated portion 28 of the negative electrode plate 20 protrudes downward, while the uncoated portion 24 of the positive electrode plate 18 protrudes upward, and the negative electrode active material 30 and The positive electrode active material 26 is disposed so as to substantially coincide with the width direction (arrow B direction). Therefore, as shown in FIG. 2 and FIG. 5 (h), in the electrode plate group 16, only the uncoated portion 24 of the positive electrode plate 18 protrudes on the upper end side, while the uncoated portion 28 of the negative electrode plate 20 on the lower end side. Only protruding.

  Therefore, in the assembly step S4, the positive electrode current collector plate 34 is welded to the upper end of the electrode plate group 16, that is, the non-applied portion 24 of the positive electrode plate 18, and the lower end of the electrode plate group 16, that is, the negative electrode plate 20 is not applied. The negative electrode current collector plate 36 is welded to the portion 28 (FIG. 5 (i)). Furthermore, the electrode plate group 16 is inserted into the battery can 12, the negative electrode current collector plate 36 is welded to the inner bottom 46 of the battery can 12, and the positive electrode current collector plate 34 and the sealing component 42 are connected by the conductive plate 44. Electrically connected. And the caulking process is performed to the opening 38 side of the battery can 12, and the lithium ion battery 10 is obtained (FIG.5 (j)). In the assembling step S4, the annular groove 40 is formed in the battery can 12, and the battery can 12 is filled with an electrolyte (not shown).

  In this case, in this embodiment, an uncoated portion 24 is provided on one end side in the width direction of the positive electrode plate 18, and an uncoated portion 28 is provided on the other end side in the width direction of the negative electrode plate 20. Then, the positive current collector 34 is welded to the uncoated portion 24, while the negative current collector 36 is welded to the uncoated portion 28, or the uncoated portion 28 is directly welded to the inner bottom 46 of the battery can 12. Has been.

  Therefore, it is not necessary to weld the current collecting lead to the positive electrode plate 18 and the negative electrode plate 20, and in the winding step S3, there is no possibility of causing a decrease in productivity due to the switching operation of the current collecting lead roll. In addition, there is no problem that the internal resistance of the lithium ion battery 10 which is caused when using a current collecting lead having a small cross-sectional area is increased. Moreover, as in the case of intermittently applying the active material at a pitch of one battery in the longitudinal direction with respect to the positive electrode current collector 50 and the negative electrode current collector 56, it is not necessary to detect the unapplied portion each time, The winding step S3 can be performed efficiently and easily at once.

  Further, in the present embodiment, as shown in FIGS. 3 and 4, the positive electrode plate 18 and the negative electrode plate 20 are arranged such that the uncoated portions 24 and 28 protrude in opposite directions, and the positive electrode active material 26. And the negative electrode active material 30 are configured to substantially coincide with each other in the width direction. Thereby, especially the effect that the lithium ion battery 10 which has desired battery performance can be manufactured efficiently, without producing the local malfunction in the battery reaction of the lithium ion battery 10 is acquired.

It is a schematic longitudinal cross-sectional explanatory drawing of the lithium ion battery which concerns on embodiment of this invention. It is principal part expansion longitudinal cross-section explanatory drawing of the said lithium ion battery. It is a disassembled perspective explanatory drawing of the electrode group which comprises the said lithium ion battery. It is a figure explaining the lamination | stacking state of the said electrode group. It is process drawing explaining the manufacturing method of the lithium ion battery which concerns on embodiment of this invention. It is a perspective explanatory view of an application process. It is a perspective explanatory view of a slit process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lithium ion battery 12 ... Battery can 16 ... Electrode plate group 18 ... Positive electrode plate 20 ... Negative electrode plate 22a, 22b ... Separator 24, 28 ... Uncoated part 26 ... Positive electrode active material 30 ... Negative electrode active material 34 ... Positive electrode collector plate 36 ... Negative electrode current collector

Claims (2)

It is a lithium ion battery configured by accommodating a plate group in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween in a battery can,
The positive electrode plate is coated with a positive electrode active material by providing an uncoated part on one end side in the width direction,
The negative electrode plate is coated with a negative electrode active material by providing an uncoated portion on the other end in the width direction opposite to the one end in the width direction,
The uncoated portions of the positive electrode plate and the negative electrode plate protrude in opposite directions and are welded to the positive electrode current collector plate and the bottom of the battery can or the negative electrode current collector plate,
The lithium ion battery, wherein the positive electrode active material of the positive electrode plate and the negative electrode active material of the negative electrode plate are arranged so as to face each other and substantially coincide with each other in the width direction. A method for producing a lithium-ion battery in which a positive electrode plate and a negative electrode plate are wound in a battery can with a separator interposed therebetween,
Applying a positive electrode active material to the belt-like positive electrode current collector at predetermined intervals in the width direction and along the longitudinal direction;
Applying a negative electrode active material to the strip-shaped negative electrode current collector at predetermined intervals in the width direction and along the longitudinal direction;
Slitting the positive electrode current collector along the longitudinal direction, and cutting each predetermined length to form a positive electrode plate having an uncoated portion on one end in the width direction; and
By slitting the negative electrode current collector along the longitudinal direction and cutting the negative electrode current collector at predetermined lengths, a negative electrode plate having an uncoated portion on the other widthwise end opposite to the widthwise one end Forming, and
An uncoated portion of each of the positive electrode plate and the negative electrode plate protrudes in opposite directions, and a separator is interposed in a state where the positive electrode active material and the negative electrode active material are substantially aligned with each other in the width direction. Obtaining the electrode plate group by winding
Welding the uncoated portion of the positive electrode plate to a positive electrode current collector plate and welding the uncoated portion of the negative electrode plate to a can bottom of the battery can or a negative electrode current collector plate;
A method for producing a lithium ion battery, comprising:

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