JP7132290B2 - Electrode sheet manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an electrode sheet.

Patent Document 1 discloses a strip-shaped composite laminated part having a laminated collector foil part in which an electrode composite material layer is laminated and an electrode composite material layer of a strip-shaped current collector foil extending in the longitudinal direction, and a current collector foil Among them, the method for producing an electrode sheet comprising a pair of strip-shaped non-composite material laminated portions extending in the longitudinal direction adjacent to both sides in the width direction of the composite material laminated portion without being laminated with the electrode composite material layer. is disclosed. Specifically, in the stretching step, with respect to a stretching roll having a small diameter portion and a large diameter portion, the composite material laminated portion faces the small diameter portion, and the non-compound laminated portion is pressed against the large diameter portion. The sheet is wound around a stretching roll to stretch the non-composite laminated portion in the longitudinal direction, and then, in the roll-pressing step, the composite laminated portion of the electrode sheet subjected to the stretching step is roll-pressed to form an electrode composite layer. is densified and the laminated collector foil portion is rolled in the longitudinal direction.

JP 2017-228349 A JP 2019-102172 A

Further, Patent Document 2 discloses the following method for manufacturing an electrode sheet. Specifically, in the electrode sheet having the above-described configuration, the non-composite laminated portion is pressed by rolling rolls to roll the non-composite laminated portion in the longitudinal direction. After that, the electrode sheet on which the non-composite laminated portion has been rolled is roll-pressed to consolidate the electrode composite layer and roll the laminated collector foil portion in the longitudinal direction. By equalizing the amount of longitudinal elongation of the non-composite laminated part due to rolling with the rolling rolls and the longitudinal elongation of the composite laminated part due to roll pressing, wrinkles generated in the electrode sheet can be reduced. ing.

By the way, in the manufacturing method of Patent Document 1, the amount of elongation in the longitudinal direction of the non-composite material lamination portion in the stretching process and the amount of elongation in the longitudinal direction of the composite material lamination part in the roll pressing process are made approximately the same, To reduce wrinkles generated in the electrode sheet. For this reason, for example, when the pressing force in the roll-pressing process is increased in order to increase the compressibility of the electrode mixture layer of the composite material lamination portion, the elongation amount of the current collector foil of the composite lamination portion due to the roll pressing increases. Therefore, in the stretching step, it is necessary to increase the tension applied to the current collector foil to increase the amount of stretching of the non-composite laminated portion. As a result, there is a possibility that the current collector foil may be broken in the stretching process.

In addition, in the manufacturing method of Patent Document 2, it is difficult to roll the entire non-composite laminated portion by applying rolling rolls to the entire non-composite laminated portion. Specifically, a rolling roll is applied to the outer portion of the non-composite laminated portion, which is located outside the adjacent portion along the composite laminated portion in the width direction, and the outer portion is longitudinally stretched. Although it can be rolled, it was difficult to apply the rolling rolls to the adjacent portion of the non-composite material laminate portion (the portion in the range extremely close to the composite material laminate portion). This is because it is necessary to separate the rolling rolls from the composite material lamination portion in order to reliably prevent the rolling rolls from coming into contact with the electrode mixture layer. For this reason, the adjacent portion of the non-composite laminated portion cannot be stretched in the longitudinal direction, and the electrode sheet tends to wrinkle.

The present invention has been made in view of the current situation, and reduces the occurrence of wrinkles in the current collector foil by making it difficult for the current collector foil to break and by stretching the adjacent part of the non-composite laminated part. An object of the present invention is to provide a method for manufacturing an electrode sheet that can

According to one aspect of the present invention, a strip-shaped composite lamination portion includes a laminated collector foil portion in which an electrode composite material layer is laminated among strip-shaped current collector foils extending in the longitudinal direction, and the electrode composite material layer, and a pair of belt-shaped current collector foils extending in the longitudinal direction adjacent to both sides in the width direction orthogonal to the longitudinal direction with respect to the composite material laminated portion without the electrode composite material layer being laminated thereon; In a method for manufacturing an electrode sheet comprising: a non-composite material laminate part of the pair of non-composite material laminate parts, the width direction of the electrode sheet is greater than the adjacent part along the composite material laminate part adjacent to the composite material laminate part For the electrode sheet subjected to the non-composite laminated part rolling step of rolling in the longitudinal direction by roll-pressing the outer part located on the outside of the composite laminated part is roll-pressed in the longitudinal direction to consolidate the electrode mixture layer and roll the laminated current collector foil portion in the longitudinal direction; In a state in which tension is applied to the current collector foil in the longitudinal direction, the composite material lamination portion faces the small-diameter portion of the drawing roll having a small-diameter portion and a pair of large-diameter portions adjacent to both sides in the axial direction. At the same time, the electrode sheet is wound around the stretching roll in such a manner that the pair of non-composite material laminated portions are in pressure contact with the pair of large diameter portions, respectively, and at least the adjacent portion of the pair of non-composite material laminated portions is and a non-composite laminate portion stretching step for stretching in the longitudinal direction.

In the manufacturing method described above, the electrode sheet having the composite material laminated portion and the non-compound laminated portion is subjected to the following steps. First, in the non-composite laminated portion rolling step, the outer portions of the pair of non-composite laminated portions (both side edges of the electrode sheet in the width direction) of the electrode sheet are roll-pressed in the longitudinal direction. Here, the outer portion is a portion of the pair of non-composite material laminated portions that is located outside the adjacent portion adjacent to the composite material laminated portion in the width direction and is adjacent to the adjacent portion. By this non-composite laminated portion rolling step, the outer portion of the non-composite laminated portion is rolled in the longitudinal direction, but the adjacent portion of the non-composite laminated portion is not rolled. Thereafter, in a roll-pressing step, the composite material lamination portion is roll-pressed in the longitudinal direction to consolidate the electrode composite material layer, and the laminated current collector foil portion (a portion of the current collector foil included in the composite lamination portion). is rolled longitudinally.

Further, in the above-described manufacturing method, in the non-composite laminated portion stretching step, at least adjacent portions of the pair of non-composite laminated portions are stretched in the longitudinal direction using stretching rolls having a small diameter portion and a large diameter portion. As a result, the adjacent portion of the non-composite laminated portion, which is difficult to stretch in the non-composite laminated portion rolling step, is stretched. In the non-composite laminated portion stretching step, the adjacent portion of the non-composite laminated portion that is not stretched in the non-composite laminated portion rolling step is preferentially stretched over the other portions. At least adjacent portions of the laminated portion can be stretched in the longitudinal direction. As a result, in addition to the laminated current collector foil part (the part of the current collector foil included in the composite material laminated part) and the outer part of the non-composite laminated part already extending in the longitudinal direction, the non-composite laminated part Since the adjacent portion can also be stretched, wrinkles occurring in the electrode sheet can be reduced.

Moreover, in the manufacturing method described above, prior to the roll pressing step, in the non-composite laminated portion rolling step, the outer portions of the pair of non-composite laminated portions are rolled in the longitudinal direction. For this reason, the "conventional method of stretching the non-composite laminated part (adjacent part and outer part) in the longitudinal direction by the non-composite laminated part stretching process and then roll-pressing the composite laminated part in the longitudinal direction by the roll-pressing process. Manufacturing method”, the outer side of the non-composite laminated part to be stretched in the non-composite laminated part stretching step has already been extended in the previous non-composite laminated part rolling step. It is possible to reduce the amount of stretching of the part. As a result, in the manufacturing method described above, breakage of the collector foil is less likely to occur in the step of stretching the non-composite laminated portion.

Further, in the method for manufacturing the electrode sheet, in the step of stretching the non-composite material laminate portion, the electrode sheet is stretched so that the pair of non-composite material laminate portions are stretched from the pair of large non-composite material laminate portions at the start of winding around the stretching rolls. The composite material laminated portion is separated from the small diameter portion while being pressed against the diameter portion, and the pair of non-compound laminated portion is pressed against the pair of large diameter portions at the end of winding on the stretching roll. At the same time, the composite material lamination portion is in pressure contact with the small diameter portion over the entire width direction, and the pair of non-compound lamination portions are in pressure contact with the pair of large diameter portions, respectively, and the composite lamination portion It is preferable that the method for manufacturing an electrode sheet terminates the stretching of the pair of non-composite material laminated portions by pressing against the small-diameter portion over the entire width direction.

In the current collector foil, a portion that is relatively easily stretched in the longitudinal direction and a portion that is relatively difficult to stretch are mixed in the longitudinal direction. For this reason, for example, in the step of stretching the laminated part of the non-composite material, "over the entire winding range from the start of winding the electrode sheet around the stretching roll to the end of winding (that is, over the entire range of the embrace angle of the electrode sheet on the stretching rolls). When the non-composite laminated part is pressed against the large diameter part and stretched without bringing the laminated material part into contact with the small diameter part, the non-composite laminated part is relatively easily stretched in the longitudinal direction. In some cases, the portion is stretched in the longitudinal direction more than the portion that is difficult to stretch, and the variation in the elongation rate (elongation amount) of the non-compound laminated portion in the longitudinal direction increases.

On the other hand, in the non-composite laminated portion stretching process described above, the electrode sheet starts to be wound around the stretching roll, and the pair of non-composite laminated portions are pressed against the pair of large diameter portions, respectively, and the composite laminated portion is spaced from the small diameter portion. As a result, tension can be concentrated on the non-composite material laminate portion, and the non-composite material laminate portion can be stretched in the longitudinal direction. Furthermore, in the electrode sheet, at the end of winding around the stretching rolls, the pair of non-composite material lamination parts are in pressure contact with the pair of large diameter parts, respectively, and the composite material lamination part is in pressure contact with the small diameter part over the entire width direction. . As a result, in the electrode sheet, the shape of the non-composite laminated portion (cross-sectional shape in the width direction) at the time when the step of stretching the non-composite laminated portion is completed (that is, the winding end position of the electrode sheet around the stretching roll) is Any portion in the longitudinal direction is equivalent.

Moreover, in the non-composite laminated portion stretching step, the pair of non-composite laminated portions are pressed against the pair of large-diameter portions, respectively, and the composite laminated portion is pressed against the small-diameter portion over the entire width direction, The stretching of the non-composite laminated portion is terminated. That is, in addition to the non-composite laminated part, the composite laminated part is pressed against the stretching rolls over the entire width direction, so that the tension in the longitudinal direction is dispersed over the entire width direction of the current collector foil. Thereafter, the non-composite laminated portion is not stretched. Therefore, in the non-composite laminated portion stretching step described above, the shape of the non-composite laminated portion (the cross-sectional shape in the width direction) is the same at any part in the longitudinal direction, and the non-composite laminated portion is stretched. Stretching is finished. As a result, the total elongation amount (total elongation rate) of the non-composite laminated portion in the longitudinal direction can be made uniform regardless of the ease of elongation in the longitudinal direction, so the non-composite laminated portion in the longitudinal direction Variation in the elongation rate (amount of elongation) can be reduced.

Further, a strip-shaped composite material lamination part having a laminated collector foil part in which an electrode composite material layer is laminated among strip-shaped current collector foils extending in the longitudinal direction, and the electrode composite material layer, and the current collector foil Among them, a pair of strip-shaped non-composite material lamination extending in the longitudinal direction adjacent to both sides in the width direction orthogonal to the longitudinal direction with respect to the composite material lamination part without laminating the electrode composite material layer In the electrode sheet, the composite material laminated portion is roll-pressed in the longitudinal direction to consolidate the electrode composite material layer and the laminated current collector foil portion. a roll-pressing step of rolling, and a small-diameter portion and a pair of large-diameter portions adjacent to both sides in the axial direction in a state in which tension is applied in the longitudinal direction to the current collector foil of the electrode sheet subjected to the roll-pressing step. With respect to the stretching roll having and a non-composite laminated part stretching step for stretching the pair of non-composite laminated parts in the longitudinal direction, and in the non-composite laminated part stretching step, the electrode sheet is transferred to the stretching roll At the beginning of winding, the pair of non-composite laminated parts are in pressure contact with the pair of large diameter parts, respectively, and the composite laminated part is separated from the small diameter part, and at the end of winding around the stretching roll, the A pair of non-composite laminated parts are in pressure contact with the pair of large diameter parts, respectively, and the composite laminated part is in pressure contact with the small diameter part over the entire width direction, and the pair of non-composite laminated parts are in contact with each other. A method for producing an electrode sheet in which stretching of the non-composite material laminated portion is completed by pressing the pair of large diameter portions, respectively, and pressing the composite material laminated portion to the small diameter portion over the entire width direction. preferable.

The manufacturing method described above includes a non-composite laminated portion stretching step similar to the manufacturing method described above. Therefore, according to the manufacturing method described above, it is possible to reduce the variation in the elongation rate (elongation amount) of the non-composite laminated portion in the longitudinal direction.

1 is a schematic diagram of an electrode sheet manufacturing apparatus; FIG. It is a top view of an electrode sheet (positive electrode sheet). FIG. 3 is a cross-sectional view taken along the line BB of FIG. 2; It is a flowchart which shows the flow of the manufacturing method of an electrode sheet. It is a figure explaining the rolling process concerning embodiment. It is a figure explaining the roll press process concerning embodiment. It is a figure explaining the extending|stretching process concerning embodiment. It is another figure explaining the extending|stretching process concerning embodiment.

Next, a method for manufacturing the electrode sheet according to the embodiment will be described. In addition, in this embodiment, the case of manufacturing the positive electrode sheet 155 as the electrode sheet will be described. FIG. 1 is a schematic diagram of an electrode sheet manufacturing apparatus 10 according to an embodiment. The manufacturing apparatus 10 includes rolling rolls 41, 42, 43, and 44, press rolls 11 and 12, and a drawing roll 30, which are arranged in this order from the upstream side to the downstream side ( 1 from the left side to the right side).

As shown in FIGS. 2 and 3 , the positive electrode sheet 155 includes a strip-shaped composite material laminate portion 154 and a pair of strip-shaped non-compound laminate portions 153 . Of these, the laminated composite material portion 154 has a laminated collector foil portion 151c in which the positive composite material layer 152 of the strip-shaped current collector foil 151 extending in the longitudinal direction DA is laminated, and the positive composite material layer 152 . On the other hand, the pair of non-composite material laminate portions 153 is not laminated with the positive electrode composite material layer 152 of the current collector foil 151, and the composite material laminate portion 154 is arranged in the width direction DB (the direction orthogonal to the longitudinal direction DA). ) extending in the longitudinal direction DA.

A method for manufacturing the electrode sheet will be described in detail below. Although the manufacturing method of the positive electrode sheet 155 is described here, the negative electrode sheet can also be manufactured in the same manner. In this embodiment, the positive electrode sheet 155 conveyed in the conveying direction DF is sequentially subjected to the processes of steps S1 to S3 shown in FIG.

First, in step S1 (non-composite laminated portion rolling step), the outer portions 153c of the pair of non-composite laminated portions 153 of the positive electrode sheet 155 (both side edges in the width direction DB of the positive electrode sheet 155) are rolled by rolling rolls. Roll pressing is performed by 41, 42 and rolling rolls 43, 44 to roll in the longitudinal direction DA (see FIGS. 1 and 5). Here, the outer portion 153c is a portion (adjacent to the adjacent portion 153b) positioned outside in the width direction DB of the adjacent portion 153b along and adjacent to the composite material stacked portion 154 of the pair of non-compound laminated portions 153. is. Since it is difficult to apply the rolling rolls 41, 42, 43, and 44 to the adjacent portion 153b of the non-composite laminated portion 153, in step 1, the adjacent portion 153b of the non-composite laminated portion 153 is rolled. can't.

Next, in step S2 (roll-pressing step), the composite material laminated portion 154 is roll-pressed by a pair of press rolls 11 and 12 to consolidate the positive electrode composite material layer 152 (electrode composite material layer), The laminated collector foil portion 151c (the portion of the collector foil 151 included in the composite laminated portion 154) is rolled in the longitudinal direction DA (see FIGS. 1 and 6).

Next, in step 3 (non-composite laminated portion stretching step), a stretching roll 30 having a cylindrical small-diameter portion 31 and a pair of large-diameter portions 35 (coaxial with the small-diameter portion 31) adjacent to both sides in the axial direction is used. to extend the pair of non-composite laminated parts 153 in the longitudinal direction DA (see FIGS. 1, 7, and 8). Specifically, in a state in which tension is applied to the current collector foil 151 in the longitudinal direction DA, the composite material laminated portion 154 faces the small diameter portion 31, and the pair of non-composite material laminated portions 153 faces the pair of large diameter portions. The positive electrode sheet 155 is wound around the drawing roll 30 at an embrace angle θ in such a manner that the positive electrode sheet 155 is pressed against the respective 35 .

As a result, the tension is concentrated on the pair of non-compound laminated portions 153 to extend the non-compound laminated portions 153 in the longitudinal direction DA. Specifically, the tension is preferentially concentrated on the adjacent portion 153b, which is not stretched in step S1, of the non-compound laminated portion 153, whereby the adjacent portion 153b is stretched preferentially over the other portions, and the At least the adjacent portion 153b of the composite material laminated portion 153 extends in the longitudinal direction DA. 7 is a cross-sectional view of the positive electrode sheet 155 at the winding start position P1 of the positive electrode sheet 155 around the stretching roll 30, and is a cross-sectional view taken along the line CC in FIG. FIG. 8 is a cross-sectional view of the positive electrode sheet 155 at the winding end position P2 of the positive electrode sheet 155 around the stretching roll 30, and is a cross-sectional view along DD in FIG.

In this way, in step S3, it is possible to extend the adjacent portion 153b of the non-composite material laminated portion 153, which was difficult to extend in the previous step S1. As a result, in addition to the laminated current collector foil portion 151c (a portion of the current collector foil 151 included in the composite material laminated portion 154) already extending in the longitudinal direction DA and the outer portion 153c of the non-compound laminated portion 153, Since the adjacent portion 153b of the non-composite laminated portion 153 can also be stretched, wrinkles occurring in the positive electrode sheet 155 can be reduced.

Moreover, in the present embodiment, prior to step S2, in step S1, the outer portions 153c of the pair of non-compound laminated portions 153 are rolled in the longitudinal direction DA. For this reason, in the present embodiment, "a conventional manufacturing method in which the non-composite laminated portion is stretched in the longitudinal direction by the non-composite laminated portion stretching step and then the composite laminated portion is roll-pressed in the longitudinal direction by the roll-pressing step. ”, the outer portion 153c of the non-composite laminated portion 153 is already stretched in the preceding step S1 (non-composite laminated portion rolling step), so that it is stretched in step S3 (non-composite laminated portion stretching step). The amount of stretching of the outer portion 153c of the non-composite laminated portion 153 can be reduced. As a result, in the present embodiment, breakage of the collector foil 151 in step S3 is less likely to occur.

By the way, in the current collector foil 151, a portion that is relatively easily stretched in the longitudinal direction DA and a portion that is relatively difficult to stretch are mixed in the longitudinal direction DA. For this reason, for example, in step S3, "over the entire winding range from the beginning of winding of the positive electrode sheet 155 around the stretching roll 30 to the end of winding (that is, over the entire range of the embrace angle θ of the positive electrode sheet 155 on the stretching roll 30). When the non-composite material laminate portion 153 is pressed against the large diameter portion 35 and stretched without bringing the material laminate portion 154 into contact with the small diameter portion 31, the non-composite material laminate portion 153 has a relatively long length. A portion that is easily stretched in the direction DA may be stretched in the longitudinal direction DA more than a portion that is difficult to be stretched, and the variation in the elongation rate of the non-compound laminate portion 153 in the longitudinal direction DA may increase.

On the other hand, in step S3 of this embodiment, as shown in FIG. At the same time, the composite material laminated portion 154 is separated from the small diameter portion 31 . As a result, tension can be concentrated on the non-compound laminated portion 153 to stretch the non-compound laminated portion 153 in the longitudinal direction DA. Furthermore, as shown in FIG. 8 , at the end of winding the positive electrode sheet 155 around the stretching roll 30 , the pair of non-composite material laminated portions 153 are pressed against the pair of large diameter portions 35 , respectively, and the composite material laminated portion 154 is widened. It is in pressure contact with the small diameter portion 31 over the entire direction DB. As a result, in the positive electrode sheet 155, the shape of the non-composite laminated portion 153 (the cross-sectional shape in the width direction DB, the figure 8) are the same at any position in the longitudinal direction DA.

Furthermore, the pair of non-composite material laminated portions 153 are pressed against the pair of large diameter portions 25, respectively, and the composite material laminated portion 154 is pressed against the small diameter portion 31 over the entire width direction DB (the state shown in FIG. 8 is achieved). ), thereby completing the stretching of the non-compound laminated portion 153 . That is, in addition to the non-composite material laminate part 153, the composite material laminate part 154 is pressed against the stretching roll 30 over the entire width direction DB, so that the tension in the longitudinal direction DA is applied to the entire width direction DB of the current collector foil 151. By dispersing it over the entire area, the non-composite laminated portion 153 is prevented from stretching thereafter.

In step S3 of the present embodiment, the difference in radius between the large-diameter portion 35 and the small-diameter portion 31 of the drawing roll 30 and the value of the tension applied to the current collector foil 151 in the longitudinal direction DA are adjusted so as to achieve the aspect described above. , and the value of the embrace angle θ. The position where the stretching of the non-composite laminated portion 153 ends is the winding end position P2 of the positive electrode sheet 155 on the stretching roll 30, or a position closer to the winding start position P1 than this. It differs depending on the ease of extension in the longitudinal direction DA of each portion on the longitudinal direction DA of 153 .

Therefore, in step S3 of the present embodiment, the shape of the non-composite laminated portion 153 (the cross-sectional shape in the width direction DB) is the same at any portion in the longitudinal direction DA, and the non-composite laminated portion 153 extension has been completed. As a result, the total elongation amount (total elongation rate) of the non-composite laminated portion 153 in the longitudinal direction DA can be made uniform regardless of the ease of elongation in the longitudinal direction DA. Variation in the elongation rate (elongation amount) of the composite material laminated portion 153 can be reduced. The positive electrode sheet 155 manufactured in this way is cut in the longitudinal direction DA at the center position of the width direction DB, for example, and used as the positive electrode of the secondary battery. Specifically, the positive electrode, the negative electrode, and the separator are wound (or laminated) to form an electrode body, and the electrode body is housed in a battery case to manufacture a secondary battery.

(Example 1)
In Example 1, the tension applied to the current collector foil 151 in the longitudinal direction DA was set to 50 N, and steps S1 to S3 were performed to manufacture the positive electrode sheet 155 . It should be noted that the tension of 50 N is the tension necessary for properly conveying the positive electrode sheet 155 in the manufacturing apparatus 10 . Specifically, step S1 was performed to set the average elongation rate in the longitudinal direction DA of the outer portion 153c of the non-composite laminated portion 153 to 0.75%. Further, Step S2 was performed to set the average elongation rate in the longitudinal direction DA of the laminated collector foil portion 151c of the composite laminated portion 154 to 0.8%. Thereafter, step S3 was performed to set the average elongation rate in the longitudinal direction DA of the outer portion 153c to 0.8%, which was equal to the average elongation rate in the longitudinal direction DA of the laminated collector foil portion 151c. After that, when the variation in elongation in the longitudinal direction DA in the outer portion 153c was investigated, it was ±0.7% (see Table 1). The average elongation in the longitudinal direction DA of the outer portion 153c is obtained as follows. Specifically, before performing step S1, a plurality of line segments extending in the longitudinal direction DA are drawn at intervals in the longitudinal direction DA at the center position of the lateral portion 153c in the width direction DB, and step S3 is performed. After that, the elongation rate of each line segment was measured, and the average value was taken as the average elongation rate. Further, the variation in elongation of the outer portion 153c is the ratio of the variation range of the elongation rate of each line segment to the average elongation rate of the outer portion 153c.

(Comparative example 1)
In Comparative Example 1, a positive electrode sheet was manufactured by performing the processes of Steps S1 and S2 in the same manner as in Example 1 without performing the process of Step S3. After that, when the variation in elongation in the longitudinal direction DA of the outer portion 153c was investigated in the same manner as in Example 1, it was ±5.0%, which was larger than that in Example 1 (see Table 1). Furthermore, since the adjacent portion 153b of the non-compound laminated portion 153 is not stretched, the positive electrode sheet has large wrinkles. Therefore, in Table 1, the evaluation is set to "x".

(Comparative example 2)
In Comparative Example 2, a positive electrode sheet was manufactured by performing the processes of Steps S2 and S3 in the same manner as in Example 1 without performing the process of Step S1. However, in step S3, the tension applied to the current collector foil 151 in the longitudinal direction DA is 250 N (five times that of the first embodiment) in order to set the average elongation rate in the longitudinal direction DA of the outer portion 153c to 0.8%. size). By applying such a large tension to the current collecting foil 151, the current collecting foil 151 sometimes broke during the step S3. Therefore, in Table 1, the evaluation is set to "x".

On the other hand, in Example 1, compared with Comparative Example 1, wrinkles generated in the positive electrode sheet 155 could be significantly reduced. Moreover, unlike Comparative Example 2, the collector foil 151 did not break during step S3. For this reason, in Table 1, the evaluation is "○". In addition, in Example 1, the average elongation rate (0.75%) in the longitudinal direction DA in the outer portion 153c of the non-compound laminated portion 153 subjected to step S1 was compared with the laminate of the composite laminated portion 154 subjected to step S2. Since the value is extremely close to the average elongation rate (0.8%) in the longitudinal direction DA of the current collector foil portion 151c, there is no need to greatly stretch the non-composite laminated portion 153 in step S3, and the current collector foil The value of the tension applied to 151 was able to be reduced to 1/5 of the value in Comparative Example 2.

Although the present invention has been described above with reference to the embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the scope of the invention. For example, in step S2, the elongation rate (average elongation rate) of the laminated collector foil portion 151c is made equal to the elongation rate (average elongation rate) of the outer portion 153c of the non-composite laminated portion 153 generated in step S1. , the composite material laminated portion 154 may be roll-pressed. In other words, the elongation rate (average elongation rate) of the outer portion 153c of the non-composite laminated portion 153 in step S1 is the same as the elongation rate (average elongation rate) of the laminated collector foil portion 151c expected in step S2. The outer portion 153c of the non-composite laminated portion 153 may be rolled so as to be equal. By doing so, it is not necessary to extend the outer portion 153c of the non-compound laminated portion 153 in step S3, and only the adjacent portion 153b of the non-composite laminated portion 153, which is difficult to roll in step S1, is stretched. It will be better if it is stretched. This makes it possible to further reduce the tension applied to the current collector foil 151 in step S3, making it even more difficult for the current collector foil 151 to break.

30 stretching roll 31 small diameter portion 35 large diameter portion 151 collector foil 151c laminated collector foil portion 152 positive electrode mixture layer (electrode mixture layer)
153 Non-composite laminated portion 153b Adjacent portion 153c Outer portion 154 Composite laminated portion 155 Positive electrode sheet (electrode sheet)
DA Longitudinal direction DB Width direction

Claims (2)

a strip-shaped composite laminate portion having a laminated collector foil portion in which an electrode composite material layer is laminated among strip-shaped current collector foils extending in the longitudinal direction, and the electrode composite material layer;
Of the current collector foil, a pair of belt-shaped strips extending in the longitudinal direction adjacent to both sides in the width direction orthogonal to the longitudinal direction with respect to the composite material laminated portion without laminating the electrode mixture layer A method for manufacturing an electrode sheet comprising a non-composite laminated portion,
With respect to the electrode sheet, the outer portions of the pair of non-composite material laminated portions, which are located outside the adjacent portions adjacent to the composite material laminated portion in the width direction, are roll-pressed in the longitudinal direction. A non-composite laminated part rolling step to be rolled,
For the electrode sheet subjected to the non-composite laminated portion rolling step, the composite laminated portion is roll-pressed in the longitudinal direction to consolidate the electrode composite material layer and the laminated current collector foil portion to the longitudinal direction. A roll press process for rolling in the direction of
A stretching roll having a small-diameter portion and a pair of large-diameter portions adjacent to both axial sides of the small-diameter portion while tension is applied in the longitudinal direction to the current collector foil of the electrode sheet subjected to the roll-pressing step, The electrode sheet is wound around the stretching rolls in such a manner that the composite material laminated portion faces the small diameter portion and the pair of non-composite material laminated portions are in pressure contact with the pair of large diameter portions. and a step of stretching at least the adjacent portion of the non-composite laminated portion in the longitudinal direction. A method for manufacturing the electrode sheet according to claim 1,
In the non-composite laminated portion stretching step,
The electrode sheet is
At the beginning of winding on the stretching roll, the pair of non-composite material laminated portions are in pressure contact with the pair of large diameter portions, respectively, and the composite material laminated portion is separated from the small diameter portion,
At the end of winding on the stretching roll, the pair of non-composite material lamination parts are in pressure contact with the pair of large diameter parts, respectively, and the composite material lamination part is in pressure contact with the small diameter part over the entire width direction. ,
The pair of non-composite laminated portions are pressed against the pair of large diameter portions, respectively, and the composite laminated portions are pressed against the small diameter portion over the entire width direction, whereby the pair of non-composite laminated portions A method for producing an electrode sheet that terminates the stretching of.

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