JP4984450B2 - Winding battery manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a wound-type batteries made by winding with insulating separators respectively a positive electrode plate and the negative electrode plate. More particularly, a method for manufacturing a wound-type batteries flat type used are enclosed in square case or the like.

  Conventionally, a battery having an electrode body in which a positive electrode plate and a negative electrode plate are wound around a separator has been used. In such a wound battery, there is a slight step in the outer shape at the end of the winding end of the electrode body. If a force is applied intensively to the stepped portion, a large pressure may be locally applied to the inside of the stepped position. Therefore, it is necessary to ensure that the end of the winding is in an appropriate position.

  Here, as one of the methods for manufacturing a wound battery, there is a method of forming a flat electrode body by crushing an electrode stack wound in a substantially cylindrical shape in the diameter direction. In this manufacturing method, the winding end end can be arranged at a substantially desired position. For example, Patent Document 1 discloses a battery in which a pressure plate is provided between a case and an electrode body so that pressure is not concentrated. In the battery described in this document, the winding end portion is disposed between the pressurizing portion by the pressurizing plate and the R portion on the side of the electrode body. Alternatively, Patent Document 2 discloses a battery in which an end portion of an electrode body is fixed with an insulating tape or an adhesive at a curved portion on the side surface of the electrode body. In the battery described in this document, the winding end portion is arranged at the R portion on the side of the electrode body.

On the other hand, there is a method for manufacturing an electrode body in which the tension at the time of winding is fixed and the flat winding core is wound around the axis from the beginning. In general, a positive electrode plate or a negative electrode plate of a battery is formed by coating each active material on a metal foil or the like, and its length is determined by characteristics such as battery capacity. Therefore, the electrode body of such a battery is manufactured by winding an electrode plate having a predetermined length flatly while applying a predetermined tension.
JP 2000-357535 A JP 2002-289257 A

  However, in the battery wound by the flat winding core described above, even if the electrode body is manufactured by winding the electrode plate of the same length, the winding end is not always at the same place. There was a problem. Since the electrode plate is not a rigid body, it is inevitable that subtle differences will occur even if it is manufactured under the same manufacturing conditions.

  For this reason, if a step due to the end of the winding comes to the winding flat part of the electrode body, for example, if a large force is applied partially due to an accident or the like, dendrite due to current concentration may occur. there were. In particular, under bad conditions such as pole side collision, there is a problem that the separator may crack from this stepped portion and may cause a short circuit. For this reason, there has been a demand to securely arrange the winding end portions at the R portions on both sides.

The present invention has been made to solve the problems method for manufacturing a wound-type batteries of the prior described above has. In other words, the problem is that even with a wound battery having an electrode body that is flatly wound by a flat core, the end of the winding end is brought to a desired position without affecting the battery characteristics. it is to provide a method for manufacturing a wound-type batteries that can be placed.

In order to solve this problem, a method for manufacturing a wound battery according to the present invention includes an electrode winding body in which an uncoated region where no active material is coated is provided on at least one of a positive electrode plate and a negative electrode plate. The positive electrode plate and the negative electrode plate are wound while being insulated by a separator, and at least a part of the uncoated region of the positive electrode plate or the negative electrode plate is wound around the electrode. When it comes to the desired area on the outer periphery of the body, the end of the wound plate after cutting the electrode plate is cut in the desired area by cutting the position in the uncoated area of the electrode plate and on the desired area. It is a manufacturing method of the winding type battery arrange | positioned in an area | region.

  According to the manufacturing method of the present invention, the uncoated region where the active material is not applied to at least one of the positive electrode plate and the negative electrode plate has a length of one half or more of the circumference of the electrode winding body. Provided. Further, the positive electrode plate and the negative electrode plate are wound while being insulated with a separator, and when at least a part of the uncoated region of the positive electrode plate or the negative electrode plate comes on a desired region on the outer periphery of the electrode winding body, A position in an uncoated region of the electrode plate and on a desired region is cut. Thereby, the winding end after the cutting of the electrode plate is arranged in a desired region.

Furthermore, in this onset bright, a wound shape flat-shaped electrode winding body, for the desired region, the outer periphery of the electrode winding body and the container inner surface when accommodating the electrode winding body in a flat container This is the R portion where a gap is formed . Thus , the winding end of the electrode winding body can be positioned in the R portion where a gap is formed between the inner surface of the container.

According to the method of manufacturing the wound-type batteries of the present invention, even in wound-type battery having a flat winding core by flattened wound electrode body, without affecting the battery characteristics and the like, the winding end The end can be arranged at a desired position.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a wound type lithium ion secondary battery.

  As shown in FIG. 1, the lithium ion secondary battery 10 of this embodiment is one in which a flatly wound electrode body 11 is enclosed in a rectangular case 12 together with an electrolytic solution. A positive terminal 13 and a negative terminal 14 protrude and are fixed to the upper portion of the case 12. Here, the electrode body 11 is obtained by winding a positive electrode plate and a negative electrode plate into a flat shape from the beginning using a flat winding core with a separator interposed therebetween. In the following, the surface of the case 12 having a large area on the front side and the back side in the figure is referred to as a plane portion.

  An example of a cross section of the secondary battery 10 of this embodiment is shown in FIGS. These represent individual differences between batteries of the same specification. In these drawings, the internal state other than the outermost periphery and the separator are omitted, and the vertical and horizontal directions are changed from those in FIG. Therefore, as shown in FIG. In any of the examples, the winding end portion 21e of the outermost positive electrode plate 21 and the winding end portion 22e of the negative electrode plate 22 are arranged in the left and right R portions.

  Here, as shown in FIG. 2, the flat surface of the electrode body 11 is inserted so as to be substantially in contact with both flat portions of the case 12, and the left and right end portions of the electrode body 11 are slightly spaced from the case 12. . This is because, in the secondary battery 10, the electrode body 11 repeatedly expands and contracts due to charging and discharging, and therefore, a certain margin is provided in advance. When the electrode body 11 expands, a wider part of the outer periphery thereof is pressed against both flat portions of the case 12 and changes to a flatter shape. And said R part is a part which is not press-contacted to case 12 even in the state expanded in this way.

  Further, the positive electrode plate 21 of the electrode body 11 shown in FIG. 2 has an aluminum foil 23 coated with a positive electrode active material 24 halfway as shown in FIG. The left end in FIG. 5 is the winding start position, from which the positive electrode active material 24 is applied to a predetermined coating region L1 determined from the battery characteristics and the like, and the positive electrode active material 24 is not subsequently applied. A coating region L2 is formed. The right end in the figure is the end of the uncoated region L2, and this position is also the winding end 21e of the positive electrode plate 21. Further, in the negative electrode plate 22 of this embodiment, as shown in FIG. 6, the negative electrode active material 26 is coated on the copper foil 25 halfway. The coating region L3 of the negative electrode active material 26 is determined from the battery characteristics and the like in the same manner as the coating region L1 of the positive electrode active material 24. The right end in the figure is the end of the uncoated region L4 and is also the winding end 22e of the negative electrode plate 22.

  Here, as described in the assignment section, in a wound body wound by a flat winding core, even if the same length of belt is wound with the same tension, The position is not necessarily the same. Therefore, even if it rolls using the positive electrode plate 21 which has the same coating area | region L1 as the electrode body 11 shown in FIG. 2, and the negative electrode plate 22 which has the same coating area | region L3, those coating area | region L1 , L3 ends at different positions depending on individual differences as shown in black in FIGS.

  Therefore, in the electrode body 11 of the present embodiment, the winding end portions 21e and 22e are always set to the R portion by changing the lengths of the uncoated region L2 of the positive electrode plate 21 and the uncoated region L4 of the negative electrode plate 22. It is arranged. The uncoated region L2 of the positive electrode plate 21 and the uncoated region L4 of the negative electrode plate 22 are 0 ≦ L2 ≦ L0, 0 ≦ L4 ≦, where L0 is half of the outer peripheral length of the electrode body 11 in the winding end state. Within the range of L0. As a result, in the electrode body 11 of this embodiment, the unfinished regions L2 and L4 allow the winding end ends 21e and 22e between the positive electrode plate 21 and the negative electrode plate 22 to be at desired positions while keeping the battery characteristics and the like as intended. Can be arranged.

  That is, in the example of FIGS. 2 to 4, the coated areas L1 and L3 are all equal, and the uncoated areas L2 and L4 are different from each other. By doing so, the battery characteristics of the secondary battery 10 enclosing the electrode body 11 of FIGS. 2 to 4 are all the same, and the end of winding of any electrode body 11 regardless of individual differences in winding method. The parts 21e and 22e are also located in the R part. Here, the length of the uncoated region L2 and the length of the uncoated region L4 are not necessarily the same.

  In addition, although the electrode body 11 of this embodiment was pressed only on both plane portions of the case 12, the left and right end portions are not connected to the side surface of the case 12 (left and right sides in FIG. 2). In addition, the winding end portions 21e and 22e of the positive electrode plate 21 and the negative electrode plate 22 may be disposed at portions corresponding to the four corners of the case 12. This is because, in this portion, the electrode body 11 is not pressed against the case 12 even when the electrode body 11 expands.

  Next, the manufacturing method of the electrode body 11 of this form is demonstrated. The manufacturing method of the present embodiment includes (1) a positive electrode plate and negative electrode plate manufacturing process, (2) a winding process, (3) a positive electrode plate and a negative electrode terminal end setting process, and (4) a separator fixing process. Have.

  First, (1) in the manufacturing process of the positive electrode plate and the negative electrode plate, the positive electrode plate 21 is manufactured as shown in FIG. 7, and the negative electrode plate 22 is manufactured as shown in FIG. In the manufacturing process of the positive electrode plate 21, the positive electrode active material 24 is applied to the strip-shaped aluminum foil 23 over the coating region L1. Next, coating is performed on the next coating region L1 while leaving the uncoated region L0. This is repeated to manufacture the strip-like positive electrode plate 21. The uncoated region L0 is half the outer peripheral length of the electrode body 11 in the winding end state.

  Similarly, in the manufacturing process of the negative electrode plate 22, the negative electrode active material 26 is applied to the strip-shaped copper foil 25 over the coating region L 3. Next, coating is performed on the next coating region L3 while leaving the uncoated region L0. This is repeated to manufacture the strip-shaped negative electrode plate 22. Note that the coating region L1 and the coating region L3 have a length range for one cell determined by battery characteristics and the like, and are generally the same length for the positive and negative electrodes. In addition, the bipolar plate manufacturing process includes the steps of applying a paste-like active material to a metal foil, drying and rolling.

  Next, in the (2) winding step, the manufactured positive electrode plate 21 and negative electrode plate 22 are wound with a separator interposed therebetween. In order from the inside, the end portions of the positive electrode plate 21, the inner separator 27, the negative electrode plate 22, and the outer separator 28 are fixed to a flat core. An uncoated region is not necessary at the end of the winding. Then, by rotating the winding core while applying a predetermined tension to each, as shown in FIGS. FIG. 10 schematically shows a cross section in a direction perpendicular to the winding axis of FIG. 9, in which most of the positive electrode plate 21 and the negative electrode plate 22 for one cell have already been wound. Is shown.

  Next, (3) in the terminal portion setting step of the positive electrode plate and the negative electrode plate, the processing is performed from the positive electrode plate 21 on the inner peripheral side. First, as shown in FIG. 11, after the positive electrode active material 24 in the coating region L1 of the positive electrode plate 21 is completely wound up, a portion of the uncoated region L0 that protrudes from the R portion is cut off. Stop. Thereby, the winding end portion 21 e of the positive electrode plate 21 is disposed in the R portion of the electrode body 11. Next, the winding core is rotated halfway, and as shown in FIG. 12, after the negative electrode active material 26 in the coated region L3 of the negative electrode plate 22 is completely wound up, from the R portion in the uncoated region L0. Cut off the protruding part and temporarily fix it. Accordingly, the winding end portion 22e of the negative electrode plate 22 is disposed in the R portion of the electrode body 11. At this time, the inner separator 27 is folded back.

  Next, in the (4) separator fixing step, the folded inner separator 27 and outer separator 28 are overlapped, wound about 1 to 3 turns, and fixed with an adhesive tape 29 at the R portion as shown in FIG. . Thus, the electrode body 11 of this embodiment was completed.

  Furthermore, the electrode body 11 manufactured as described above is enclosed in a case 12, and the lithium ion secondary battery 10 of this embodiment can be obtained. First, the positive electrode terminal 13 is connected to the positive electrode plate 21 of the electrode body 11, and the negative electrode terminal 14 is connected to the negative electrode plate 22 so as to protrude toward the adhesive tape 29. Then, the electrode body 11 to which the bipolar terminals 13 and 14 are connected is inserted into the case 12. At this time, since the bipolar terminals 13 and 14 are directed upward in FIG. 1, the adhesive tape 29 is also arranged on the upper side. Furthermore, it is sealed by filling the electrolyte and fixing the lid. Thereby, the secondary battery 10 of this embodiment shown in FIG. 1 was completed.

  Next, as shown in FIG. 14, the secondary battery 10 manufactured in this manner was subjected to a vertical crush test assuming a pole-side collision. In this test, a crushing bar 31 in the vertical direction in the figure was caused to collide with a predetermined load near the center of the secondary battery 10. For comparison, a secondary battery similar to that of the present embodiment was manufactured as a comparative example, except that the winding end ends of the positive electrode plate and the negative electrode plate were arranged at positions facing the flat portion of the case. As a result, as shown in FIG. 15, in the comparative example, a short circuit occurred at a load of 2.4 tons, whereas in the secondary battery 10 of this embodiment, no short circuit occurred at a load of 3.0 tons. . Therefore, it can be said that the secondary battery 10 of this embodiment has improved withstand voltage against accidents such as pole side collisions.

As described in detail above, according to the secondary battery 10 of the present embodiment, since the uncoated areas are provided in advance on the positive electrode plate 21 and the negative electrode plate 22, winding is performed using a flat type winding core. After that, the winding end portions 21e and 22e can be arranged at desired positions by cutting off in the uncoated region. Therefore, even with a wound battery having the electrode body 11 wound flat by a flat winding core, the winding end can be arranged at a desired position without affecting the battery characteristics and the like. It has become a method of manufacturing the wound-type batteries.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in the above embodiment, the winding end portion 21e of the positive electrode plate 21 and the winding end portion 22e of the negative electrode plate 22 are arranged in the R portion on the left and right sides, both of which are the R portion on the same side. You may make it arrange | position to.
Further, for example, the present invention is not limited to a lithium ion secondary battery, and can be applied to any wound type battery.

It is a perspective view which shows the external appearance shape of the lithium ion secondary battery of this form. It is sectional drawing which shows the electrode body of a lithium ion secondary battery. It is sectional drawing which shows the electrode body of a lithium ion secondary battery. It is sectional drawing which shows the electrode body of a lithium ion secondary battery. It is explanatory drawing which shows the positive electrode plate of an electrode body. It is explanatory drawing which shows the negative electrode plate of an electrode body. It is explanatory drawing which shows the positive electrode plate of an electrode body. It is explanatory drawing which shows the negative electrode plate of an electrode body. It is explanatory drawing which shows the winding method of an electrode body. It is explanatory drawing which shows the winding method of an electrode body. It is explanatory drawing which shows the winding method of an electrode body. It is explanatory drawing which shows the winding method of an electrode body. It is explanatory drawing which shows the winding method of an electrode body. It is explanatory drawing which shows a pole side collision test. It is explanatory drawing which shows the result of a pole side collision test.

Explanation of symbols

10 Lithium ion secondary battery (winding battery)
11 Electrode body (electrode winding body)
12 Case (container)
21 Positive electrode plate 22 Negative electrode plate 24 Positive electrode active material 26 Negative electrode active material

Claims (1)

At least one of the positive electrode plate and the negative electrode plate is provided with an uncoated region where the active material is not applied over a length of one-half or more of the circumference of the electrode winding body,
Winding the positive electrode plate and the negative electrode plate in a flat shape while being insulated by a separator;
Wherein at least a portion of the positive electrode plate or the uncoated area of the negative electrode plate, the outer periphery of the electrode winding body, wherein the container and the outer periphery of the electrode winding body when the electrode winding body is accommodated in a flat container When it comes to the R part where a gap is formed between the inner surface of the electrode plate and the position of the electrode plate in the uncoated region and the position on the R part is cut, the winding after the electrode plate is cut wound type method for producing a battery, characterized by arranging an end edge in the R portion.

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