JP7252923B2 - 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 wrapped around a stretching roll to stretch the non-composite laminate in the longitudinal direction. After that, in the roll-pressing step, the electrode sheet subjected to the stretching step is roll-pressed to compact the electrode mixture layer and roll the laminated collector foil portion in the longitudinal direction.

JP 2017-228349 A

By the way, in the manufacturing method of Patent Document 1, the elongation rate in the longitudinal direction of the non-composite material laminated portion in the stretching process and the laminated current collector foil portion (the portion included in the composite material laminated portion of the current collector foil) in the roll press process ) to reduce the wrinkles generated in the electrode sheet by making the elongation rate in the longitudinal direction about the same. 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 in the composite material lamination portion, the elongation rate of the current collector foil in the composite lamination portion due to roll pressing increases. (For example, when the elongation rate is 0.8% or more), it is necessary to increase the tension applied to the current collector foil in the stretching step to increase the amount of stretching of the non-composite laminated portion. However, increasing the tension applied to the current collector foil in the stretching process may cause breakage of the non-composite laminated portion. For example, when the elongation in the longitudinal direction of the laminated current collector foil is 0.8% or more by the roll pressing process, the elongation in the longitudinal direction of the non-composite laminated part is In order to equalize the elongation rate in the longitudinal direction of the foil part, the tension applied to the current collector foil was set so that the elongation rate in the longitudinal direction of the non-composite laminated part was 0.8% in the stretching process. Therefore, when the non-composite material laminate portion is stretched, there is a possibility that the non-composite material laminate portion may be broken.

The present invention has been devised in view of such circumstances, and provides a method for manufacturing an electrode sheet in which breakage of the non-composite laminated portion is less likely to occur and wrinkles occurring in the electrode sheet can be reduced. for the purpose.

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; , wherein the electrode sheet is roll-pressed in the longitudinal direction to densify the electrode mixture layer and the laminate A roll-pressing step of rolling the current collecting foil portion in the longitudinal direction, and the electrode sheet subjected to the roll-pressing step is subjected to the pair of and a non-composite laminate stretching step of stretching the pair of non-composite laminates in the longitudinal direction of the electrode sheet subjected to the annealing step. The elongation rate in the longitudinal direction of the laminated current collector foil portion in the roll pressing step is 0.8% or more and 1.0% or less, and the elongation at break of the non-composite laminated portion subjected to the annealing step. is greater than 1.0%, and the elongation rate in the longitudinal direction of the non-composite laminated portion in the non-composite laminated portion stretching step is within the range of 0.8% or more and 1.0% or less. It is a method of manufacturing an electrode sheet with a value .

In the manufacturing method described above, the electrode sheet having the composite material laminate portion and the non-composite material laminate portion is sequentially subjected to the following steps. First, 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.

After that, in the annealing step, the pair of non-compound laminated portions of the electrode sheet subjected to the roll-pressing step are annealed. Specifically, the pair of non-composite laminated parts is heated at a temperature within the range of 250 ° C. or higher and less than the melting point Tm of the non-composite laminated part (that is, the temperature range of 250 ° C. or higher and lower than Tm). Anneal. Annealing the non-composite laminated part in such a temperature range makes it easier to extend the non-composite laminated part in the longitudinal direction, and further increases the elongation at break of the non-composite laminated part. The elongation at break is the longitudinal elongation rate of the non-composite laminated portion when the non-composite laminated portion is broken by stretching the non-composite laminated portion in the longitudinal direction. In other words, it is the longitudinal elongation rate of the non-composite laminated part from when the non-composite laminated part starts to be stretched in the longitudinal direction until the non-composite laminated part breaks.

Next, in the non-composite laminate portion stretching step, the pair of non-composite laminate portions of the electrode sheet subjected to the annealing step are stretched in the longitudinal direction. As a result, in addition to the laminated current collector foil portion (a portion of the current collector foil included in the composite material laminated portion) that has been longitudinally stretched in the roll pressing process, the pair of non-compound laminated portions can also be longitudinally extended. can be done. As a result, the current collector foil can be stretched in the longitudinal direction over the entire width of the electrode sheet, so wrinkles occurring in the electrode sheet (current collector foil) can be reduced. Furthermore, since the breaking elongation of the non-compound laminated portion is increased by the preceding annealing step, breakage of the non-composite laminated portion is less likely to occur in the non-compound laminated portion stretching step.

In addition, as the non-composite laminated portion stretching step, for example, "a pair of small-diameter portions and a pair of adjacent ones on both sides in the axial direction are stretched in a state in which tension is applied in the longitudinal direction to the current collector foil of the electrode sheet that has been annealed. The electrode sheet is wound around the stretching roll in such a manner that the composite material laminated portion faces the small diameter portion of the stretching roll having the large diameter portion, and the pair of non-composite material laminated portions are in pressure contact with the pair of large diameter portions. and stretching the pair of non-composite laminated parts in the longitudinal direction.

In the manufacturing method described above, the elongation rate in the longitudinal direction of the laminated collector foil portion (the portion of the collector foil included in the composite laminated portion) in the roll press process is set to 0.8% or more and 1.0% or less. The value is within the range. That is, in the roll-pressing step, the electrode sheet composite laminated portion is roll-pressed in the longitudinal direction to consolidate the electrode composite layer, and the laminated collector foil portion is rolled in the longitudinal direction to obtain the laminated collector foil. The elongation rate of the foil portion in the longitudinal direction is set to a value within the range of 0.8% or more and 1.0% or less. In addition, the case where the elongation rate in the longitudinal direction of the laminated current collector foil portion becomes a value within the range of 0.8% or more and 1.0% or less by roll-pressing the composite material laminated portion of the electrode sheet, This is the case where the press pressure is increased to increase the degree of compaction of the electrode mixture layer compared to the conventional case.

By the way, in the above-described manufacturing method, as described above, the breaking elongation rate of the non-composite laminated portion is increased by annealing the pair of non-composite laminated portions in the annealing step before performing the non-composite laminated portion stretching step. is increasing. Specifically, the pair of non-composite laminated parts are heated and annealed at a temperature of 250 ° C. or higher and less than the melting point of the non-composite laminated part, so that the non-composite laminated part is broken. Make the elongation greater than 1.0%.

As a result, in the non-composite laminated part stretching step, the pair of non-composite laminated parts are stretched in the longitudinal direction without breaking the non-composite laminated parts, and each non-composite laminated part is stretched in the longitudinal direction. It becomes possible to set the elongation rate to a value within the range of 0.8% or more and 1.0% or less. As a result, even when the elongation in the longitudinal direction of the laminated current collector foil portion is set to a value within the range of 0.8% or more and 1.0% or less by the roll pressing step, the non-composite laminated portion stretching step can be performed. Therefore, it is possible to sufficiently reduce the difference between the longitudinal elongation rate of the laminated current collector foil portion and the longitudinal elongation rate of the non-composite laminated portion (for example, It is possible to reduce the wrinkles that occur in the electrode sheet (current collector foil).

1 is a schematic view of an electrode sheet manufacturing apparatus according to an embodiment; FIG. 1 is a plan view of an electrode sheet (positive electrode sheet) according to an embodiment; FIG. FIG. 3 is a cross-sectional view taken along the line BB of FIG. 2; 4 is a flow chart showing the flow of the method for manufacturing an electrode sheet according to the embodiment. It is a figure explaining the roll press process concerning embodiment. It is a figure explaining the annealing process concerning embodiment. It is a figure explaining the extending|stretching process concerning embodiment. It is a figure which shows the relationship between the heating temperature of a non-composite material lamination|stacking part, and a breaking elongation rate.

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 has press rolls 11 and 12, heating devices 41 and 42, and a drawing roll 30, which are arranged in this order from the upstream side to the downstream side (the left side in FIG. 1) in the conveying direction DF of the positive electrode sheet 155. to the right).

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. Note that the collector foil 151 is made of metal foil (specifically, aluminum foil).

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 the present embodiment, the positive electrode sheet 155 conveyed in the conveying direction DF (the direction coinciding with the longitudinal direction DA of the positive electrode sheet 155) is sequentially subjected to steps S1 to S3 shown in FIG.

First, in step S1 (roll-pressing step), a pair of press rolls 11 and 12 are used to roll-press the composite material laminate portion 154 to consolidate the positive electrode composite material layer 152 (electrode composite material layer). The electrical foil portion 151c (a portion of the current collector foil 151 included in the composite material laminated portion 154) is rolled in the longitudinal direction DA (see FIGS. 1 and 5).

Next, proceeding to step S2 (annealing step), the pair of non-composite laminated portions 153 of the positive electrode sheet 155 subjected to step S1 (roll pressing step) are annealed (see FIGS. 1 and 6). Specifically, using the heating devices 41 and 42, the temperature within the range of 250 ° C. or higher and less than the melting point Tm of the non-compound laminated portion 153 (aluminum foil in this embodiment) (that is, 250 ° C. or higher In a temperature range below Tm), the pair of non-composite laminated parts 153 are heated and annealed. Note that the melting point Tm of the aluminum foil forming the non-composite laminated portion 153 is approximately 660°C.

In this embodiment, induction heating devices (IH heaters) are used as the heating devices 41 and 42 . The heating device 41 is arranged to face the surface of one of the pair of non-composite laminated parts 153 (on the right side in FIG. 6), and induces the one non-composite laminated part 153 heat up. Specifically, one non-composite material laminate portion 153 is annealed by heating to a temperature (annealing temperature) within a range of 250° C. or more and less than the melting point of the non-composite material laminate portion 153 . In addition, the heating device 42 is arranged to face the surface of the other (left side in FIG. 6) non-composite laminated portion 153 of the pair of non-composite laminated portions 153, and the other non-composite laminated portion 153 is induction-heated. Specifically, the other non-composite material laminate portion 153 is annealed by heating to a temperature (annealing temperature) within a range of 250° C. or more and less than the melting point of the non-composite material laminate portion 153 .

By annealing the non-composite laminated part 153 in such a temperature range, the non-composite laminated part 153 can be easily stretched in the longitudinal direction DA, and the breaking elongation rate (%) of the non-composite laminated part 153 can increase The breaking elongation rate is the elongation rate of the non-compound laminated portion 153 in the longitudinal direction DA when the non-compound laminated portion 153 is broken by stretching the non-compound laminated portion 153 in the longitudinal direction DA. In other words, it is the elongation rate in the longitudinal direction DA of the non-compound laminated portion 153 from the start of stretching of the non-compound laminated portion 153 in the longitudinal direction DA until the non-compound laminated portion 153 breaks.

Next, in step S3 (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. Then, the pair of non-composite material laminate portions 153 subjected to step S2 (annealing step) are stretched in the longitudinal direction DA (see FIGS. 1 and 7). 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 are arranged to face 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. Note that P1 in FIG. 1 is the winding start position of the positive electrode sheet 155 around the stretching roll 30 and P2 is the winding end position of the positive electrode sheet 155 around the stretching roll 30 .

By doing so, 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) stretched in the longitudinal direction DA in step S1 (roll press step), a pair of can also extend in the longitudinal direction DA. As a result, the current collector foil 151 can be stretched in the longitudinal direction DA over the entire width direction DB of the positive electrode sheet 155, so wrinkles occurring in the positive electrode sheet 155 (current collector foil 151) can be reduced. Furthermore, since the breaking elongation rate of the non-composite material laminated portion 153 is increased by the previous step S2 (annealing step), the non-composite material laminated portion 153 is less likely to break in step S3.

7 is a cross-sectional view of the positive electrode sheet 155 and the stretching roll 30 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. In step S3 of the present embodiment, as shown in FIG. 7, at the start 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 are joined together. The material lamination 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.

By the way, in the present embodiment, the elongation rate of the laminated collector foil portion 151c in the longitudinal direction DA in step S1 (roll press process) is set to a value within the range of 0.8% or more and 1.0% or less. Specifically, in this embodiment, in order to increase the battery capacity, the roll press pressure is increased to increase the degree of compaction of the positive electrode mixture layer 152 compared to the conventional case. Therefore, the elongation rate of the laminated current collector foil portion 151c in the longitudinal direction DA in step S1 (roll press step) becomes a large value of 0.8% or more.

On the other hand, in the present embodiment, before performing step S3 (non-composite laminated portion stretching step), in step S2 (annealing step), the temperature is 250° C. or higher and less than the melting point of the non-composite laminated portion 153. The pair of non-composite laminated parts 153 are heated and annealed at a temperature within (annealing temperature). Thereby, the breaking elongation rate of the non-composite material laminated portion 153 can be made larger than 1.0% (more specifically, 1.5% or more).

For this reason, in step S3, the pair of non-compound laminated portions 153 are stretched in the longitudinal direction DA without breaking the non-compound laminated portions 153, and each non-compound laminated portion 153 is stretched in the longitudinal direction DA. It becomes possible to set the elongation rate to a value within the range of 0.8% or more and 1.0% or less. As a result, even if the elongation rate in the longitudinal direction DA of the laminated current collector foil portion 151c in step S1 is set to a value within the range of 0.8% or more and 1.0% or less, by performing step S3, the laminated current collector foil It is possible to sufficiently reduce the difference between the elongation rate in the longitudinal direction DA of the portion 151c and the elongation rate in the longitudinal direction DA of the non-composite laminated portion 153 (for example, the elongation rate in the longitudinal direction DA of both can be made equal), and wrinkles occurring in the positive electrode sheet 155 (collector foil 151) can be reduced.

The positive electrode sheet 155 manufactured as described above is cut, for example, in the longitudinal direction DA at the center position of the width direction DB, and used as a positive electrode of a 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.

<Tensile test>
First, from the positive electrode sheet 155 before the processing of steps S1 to S3, the aluminum foil constituting the non-composite laminated portion 153 is cut out by a certain length in the longitudinal direction DA to prepare a plurality of test pieces. bottom. Next, each test piece was annealed at different annealing temperatures (heating temperatures) and then subjected to a tensile test (pulling in the longitudinal direction DA) to measure the elongation at break in the longitudinal direction DA. The results are shown in FIG. FIG. 8 is a diagram showing the relationship between the heating temperature (annealing temperature) and the elongation at break of the non-compound laminated portion 153 (test piece).

In this test, a plurality of test pieces were annealed at each heating temperature (annealing temperature), and a tensile test was performed on the plurality of test pieces at each heating temperature. Therefore, the elongation at break at each heating temperature shown in FIG. 8 is the average value of the elongation at break of a plurality of test pieces at each heating temperature. Further, in this test, each test piece was annealed by heating in a muffle furnace for 1 minute. Moreover, the data at the heating temperature of 20° C. in FIG. 8 are the data of the test piece subjected to the tensile test without annealing.

As shown in FIG. 8, by annealing the non-composite material laminate portion 153 at a heating temperature (annealing temperature) of 250° C. or higher, the breaking elongation of the non-composite laminate portion 153 is increased compared to the case where the annealing treatment is not performed. rate can be increased. Specifically, by annealing the non-composite material laminate portion 153 at a heating temperature (annealing temperature) of 250° C. or higher, the breaking elongation rate of the non-composite material laminate portion 153 in the longitudinal direction DA is increased from 1.0% to 1.0%. can also be increased (specifically, elongation at break can be increased to 1.5% or more). However, in order to prevent the non-composite material laminate portion 153 from melting, the annealing temperature must be lower than the melting point of the non-composite material laminate portion 153 . From this result, by annealing the non-composite laminated part 153 at a temperature (annealing temperature) within a range of 250° C. or more and less than the melting point of the non-composite laminated part 153, the non-composite laminated part 153 It can be said that the elongation at break in the longitudinal direction DA can be increased.

<Example 1>
In Example 1, the positive electrode sheet 155 was manufactured by sequentially performing the processes of steps S1 to S3 described above. The width dimension of the positive electrode sheet 155 (current collector foil 151) is 215 mm, and the width dimension of the composite material laminated portion 154 is 150 mm. Further, in step S1, the positive electrode sheet 155 is conveyed at a speed of 10 m/min, and press rolls 11 and 12 having a diameter of 500 mm are used to perform roll pressing at a linear pressure of 2.3 t/cm. By this step S1, the elongation rate of the laminated collector foil portion 151c in the longitudinal direction DA became 0.8%.

Further, in step S2, the pair of non-composite material laminated portions 153 are annealed at an annealing temperature (heating temperature) of 300° C. and a heating time (annealing time) of 20 seconds. By this annealing treatment, the elongation at break of the non-composite laminated portion 153 can be made greater than 1.0% (more specifically, the elongation at break is 1.5% or more) (see FIG. 8). Note that the heating time is the time required for the pair of non-compound laminated portions 153 to pass in front of the heating devices 41 and 42 . In step S3, the tension applied to the positive electrode sheet 155 is set to 50 N, and the difference in radius between the small diameter portion 31 and the large diameter portion 35 of the stretching roll 30 is set to 1.0 mm. By this step S3, the elongation rate of the non-composite material laminated portion 153 in the longitudinal direction DA was set to 0.8% (that is, equivalent to the elongation rate of the laminated collector foil portion 151c generated in step S1).

In this Example 1, no breakage of the non-composite material laminate portion 153 occurred in step S3. This is because the breaking elongation rate of the non-composite material laminated portion 153 is made larger than 1.0% by the previous step S2 (annealing step). Moreover, when the positive electrode sheet 155 of Example 1 was visually inspected for wrinkles, no wrinkles were found.

<Comparative Example 1>
In Comparative Example 1, unlike Example 1, the positive electrode sheet was manufactured by performing the treatments in the order of step S2 (annealing step), step S1 (roll pressing step), and step S3 (stretching step of non-composite laminated portion). . Comparative Example 1 differs from Example 1 only in the order of the steps (processes), and the conditions of each step are the same.

In Comparative Example 1, step S1 (roll pressing step) is performed in a state in which the stiffness of the current collector foil 151 is lowered by performing step S2 (annealing step). A large number of wrinkles were generated in the (non-composite laminated part). Furthermore, in step S3, the non-composite laminated portion 153 was broken starting from the wrinkles. From this result, it can be said that it is not preferable to perform the annealing process before the roll press process.

<Comparative Example 2>
In Comparative Example 2, the positive electrode sheet was manufactured by performing the processes of steps S1 and S3 in this order without performing the process of step S2 (annealing process). However, in step S3 of Comparative Example 2, the tension applied to the current collector foil 151 in the longitudinal direction DA was 250 N (implementation 5 times the size of Example 1). In Comparative Example 2, since step S2 (annealing step) is not performed, the non-composite laminated portion 153 is in a state where it is difficult to stretch compared to Example 1 when step S3 is performed. is. In step S3 of Comparative Example 2, since it was necessary to apply a large tension to the current collector foil 151, the current collector foil 151 was sometimes broken.

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 the embodiment, the elongation rate in the longitudinal direction DA of the laminated current collector foil portion 151c in step S1 (roll pressing process) was set to a value within the range of 0.8% or more and 1.0% or less. A value greater than 0% may be used. However, since the breaking elongation rate of the non-composite laminated portion 153 after the step S2 (annealing step) is about 1.5%, the laminated collector foil portion 151c in step S1 (roll pressing step) The elongation in the longitudinal direction DA is preferably less than 1.5%.

10 Manufacturing equipment 11, 12 Press roll 30 Stretching rolls 41, 42 Heating device 151 Current collector foil 151c Laminated current collector foil portion 152 Positive electrode mixture layer (electrode mixture layer)
153 Non-composite laminated portion 154 Composite laminated portion 155 Positive electrode sheet (electrode sheet)
DA Longitudinal direction DB Width direction

Claims (1)

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,
a roll-pressing step of roll-pressing the electrode sheet in the longitudinal direction to densify the electrode mixture layer and roll the laminated collector foil portion in the longitudinal direction;
An annealing step of annealing the pair of non-composite material laminate portions in a temperature range of 250° C. or more and less than the melting point of the non-composite material laminate portion of the electrode sheet subjected to the roll pressing step;
a non-composite laminate portion stretching step of stretching the pair of non-composite laminate portions in the longitudinal direction for the electrode sheet subjected to the annealing step ,
The elongation rate in the longitudinal direction of the laminated current collector foil portion in the roll pressing step is 0.8% or more and 1.0% or less,
The elongation at break of the non-composite laminated portion subjected to the annealing step is greater than 1.0%,
A method for producing an electrode sheet, wherein the elongation rate of the non-composite laminated portion in the longitudinal direction in the non-composite laminated portion stretching step is a value within the range of 0.8% or more and 1.0% or less.

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