JP2020161331A - Secondary battery and method for manufacturing secondary battery - Google Patents

Abstract

To provide a secondary battery and a method for manufacturing a secondary battery, capable of preventing a short circuit due to the contact of electrode sheets and also capable of increasing the power storage capacity of a secondary battery.SOLUTION: A secondary battery according to an embodiment of the present invention includes an electrode body in which a positive electrode sheet, a negative electrode sheet 100, and separators 110a, 110b insulating the positive electrode sheet and the negative electrode sheet 100 are laminated. The negative electrode sheet 100 and the separators 110a, 110b are at least partially bonded by an adhesive while the separators 110a, 110b are laminated on both faces of the negative electrode sheet 100, and at least one end of the negative electrode sheet 100 and at least one end of the separators 110a, 110b are coated with an adhesive while the ends are aligned.SELECTED DRAWING: Figure 2

Description

The present invention relates to a secondary battery and a method for manufacturing a secondary battery, and more particularly to a secondary battery including an electrode body in which a positive electrode sheet, a negative electrode sheet and a separator are laminated, and a method for manufacturing the secondary battery.

Currently, secondary batteries such as lithium-ion batteries and nickel-metal hydride batteries are used in electric vehicles, hybrid vehicles, plug-in hybrid vehicles, and the like. The secondary battery includes an electrode body formed by laminating a positive electrode sheet, a negative electrode sheet, and a separator in the housing thereof. For the purpose of improving the productivity of a secondary battery provided with such an electrode body, a manufacturing method has been proposed in which a positive electrode sheet, a negative electrode sheet, and a separator are laminated and then cut.

For example, in the method for manufacturing a secondary battery disclosed in Patent Document 1, a separator and an electrode sheet that are pulled out from a reel and overlapped are cut while applying heat with a cutting blade equipped with a heater, and the cut surface of the separator and the electrode sheet is welded. Let me. This is intended to integrate the separator and the electrode sheet, prevent the active material of the electrode sheet from being exposed, and prevent a short circuit due to contact between the electrode sheets.

Japanese Unexamined Patent Publication No. 2006-324095

However, in the method for manufacturing a secondary battery disclosed in Patent Document 1, the entire edge portion of the electrode sheet cannot be covered by the heat-melted separator (see FIG. 2B of Patent Document 1), and the electrode sheet cannot be covered. There is a risk that the active material at the ends will be exposed and the adjacent electrode sheets will come into contact with each other, causing a short circuit. In order to prevent this, a method using a separator having a larger area than the electrode sheet can be considered, but in this method, a space for accommodating such a separator must be secured in the housing of the secondary battery. Therefore, there is a problem that the effective area of the electrode sheet cannot be increased and the storage capacity is limited.

Further, since tension is applied to the separator pulled out from the reel (see FIG. 1B of Patent Document 1), if the separator is cut in that state, the separator contracts due to the contraction force which is a reaction of the tension. The active material existing on the surface of the electrode sheet may be exposed.

The present invention has been made to solve such a problem, and is a secondary battery and a secondary battery capable of preventing a short circuit due to contact of an electrode sheet and increasing the storage capacity of the secondary battery. It is an object of the present invention to provide the manufacturing method of.

The secondary battery according to the embodiment of the present invention includes an electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator that insulates the positive electrode sheet and the negative electrode sheet are laminated. The negative electrode sheet and the separator are at least partially adhered with an adhesive in a state where the separator is laminated on both sides of the negative electrode sheet, and the negative electrode sheet and at least one end of the separator are aligned. It is covered with an adhesive in a fresh state.

Further, a larger amount of adhesive may be attached to the portion near the end portion of the negative electrode sheet and the separator than to the other portions of the negative electrode sheet and the separator.

Further, two of the four ends of the negative electrode sheet that do not include the current collector and the two ends of the separator corresponding thereto may be coated with an adhesive in an aligned state. ..

Further, the three ends of the negative electrode sheet that do not include the current collector and the corresponding three ends of the separator may be coated with an adhesive in an aligned state. ..

Further, three of the four ends of the negative electrode sheet that do not include the current collector and the corresponding three ends of the separator are coated with an adhesive in an aligned state. A portion other than the current collector portion at the remaining end portion of the negative electrode sheet and the end portion of the separator corresponding thereto may be coated with an adhesive in an aligned state.

Further, the size of the negative electrode sheet and the separator is larger than the size of the positive electrode sheet, and the negative electrode sheet and the separator have an expansion region that does not face the positive electrode sheet, and at least a part of the expansion region. In the above, it is preferable that a larger amount of the adhesive is attached than the negative electrode sheet and other parts of the separator.

Further, the method for manufacturing a secondary battery according to an embodiment of the present invention is to manufacture a secondary battery including an electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator that insulates the positive electrode sheet and the negative electrode sheet are laminated. The method is a first step of applying an adhesive to at least one of the negative electrode sheet and the separator, and two of the separators are arranged on both sides of the negative electrode sheet, and the negative electrode sheet and the separator are bonded by the adhesive. This includes a second step of heating and cutting the negative electrode sheet and the separator adhered by the adhesive, and coating the cut surface of the negative electrode sheet and the separator with the adhesive.

Further, in the first step, it is preferable to apply an amount of adhesive capable of covering the cut surface to the negative electrode sheet, the cut portion which is the cut portion of the separator, and the vicinity portion of the cut portion. ..

Further, in the first step, a larger amount of adhesive can be applied to the cut portion and the vicinity portion than to the other portions of the negative electrode sheet and the separator.

Further, in the first step, the adhesive can be applied only to the cut portion and the vicinity portion.

Further, in the third step, the negative electrode sheet and the separator on the side where the current collector does not exist can be heat-cut.

Further, in the third step, the negative electrode sheet other than the portion corresponding to the current collector can be heat-cut together with the separator.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a secondary battery and a method for manufacturing a secondary battery, which can prevent a short circuit due to contact of an electrode sheet and increase the storage capacity of the secondary battery.

It is a perspective view which shows the negative electrode sheet and the separator which concerns on one Embodiment of this invention. It is sectional drawing of the negative electrode sheet and separator which concerns on one Embodiment of this invention. It is a perspective view which shows the negative electrode sheet and the separator which concerns on other embodiment of this invention. It is a figure which shows the cutting process of the negative electrode sheet and the separator which concerns on other embodiment of this invention.

The secondary battery of the present invention includes an electrode body in which a positive electrode sheet, which is a positive electrode sheet, a negative electrode sheet, which is a negative electrode sheet, and a separator that insulates the positive electrode sheet and the negative electrode sheet are laminated. The positive electrode sheet includes a positive electrode current collector (aluminum or the like) and a positive electrode mixture layer formed on both sides of the positive electrode current collector. The positive electrode mixture layer is composed of a positive electrode mixture slurry containing a positive electrode active material (lithium cobalt oxide, etc.), a conductive agent, and a binder. The negative electrode sheet includes a negative electrode current collector (copper or the like) and a negative electrode mixture layer formed on both sides of the negative electrode current collector. The negative electrode mixture layer is composed of a negative electrode mixture slurry containing a negative electrode active material (graphite or the like), a conductive agent, and a binder.

In the method for manufacturing a secondary battery of the present invention, a first step of applying an adhesive to at least one of a negative electrode sheet and a separator, and a first step of arranging two separators on both sides of the negative electrode sheet and adhering them with an adhesive. The second step includes a third step of heat-cutting the negative electrode sheet and the separator adhered by the adhesive and coating the cut surface of the negative electrode sheet and the separator with the adhesive. Hereinafter, the first step and the second step are referred to as an bonding step, and the third step is referred to as a cutting step. Further, the negative electrode sheet before cutting is referred to as a negative electrode sheet before cutting, and the negative electrode sheet after cutting is referred to as a negative electrode sheet after cutting. Further, the positive electrode sheet before cutting is referred to as a positive electrode sheet before cutting, and the positive electrode sheet after cutting is referred to as a positive electrode sheet after cutting.

<One Embodiment of the present invention>
An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing a negative electrode sheet before cutting and a separator according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a negative electrode sheet before cutting, a negative electrode sheet after cutting, and a separator according to an embodiment of the present invention. FIG. 1 shows a state in which the uncut negative electrode sheet 100 having the current collector 101 formed in the step performed before the bonding step and the separators 110a and 110b are laminated and bonded. .. In the present embodiment, in order to prevent a short circuit due to contact between the electrode sheets, the areas of the separators 110a and 110b after cutting are set on the opposite side between the side where the current collector 101 exists and the side where the current collector 101 exists. It is configured to be larger than the area of the negative electrode sheet 100 after cutting. FIG. 2 shows the negative electrode sheets 100 and separators 110a and 110b before cutting before being heat-cut in the cutting step, and the negative electrode sheets 100 and separators 110a and 110b after cutting after being heat-cut in the cutting step. ..

The act of applying an adhesive to the pre-cut negative electrode sheet 100 and the separators 110a and 110b in the bonding step includes an act of applying an adhesive to these and an act of spraying. Hereinafter, for convenience of explanation, the act of applying the adhesive, which is one aspect of the act of applying the adhesive, will be described.

In the bonding step, an adhesive can be applied to all or a part of the contact surfaces of the uncut negative electrode sheet 100 and one or both of the separators 110a and 110b. When an adhesive is applied to a part of these contact surfaces, at least the pre-cut negative electrode sheet 100 and the cut portions (hereinafter referred to as “cut portions”) 200 of the separators 110a and 110b and the cut portion. An adhesive is applied to the neighboring portions 201 and 202. It is preferable to apply a larger amount of adhesive to the cut portion 200 and the neighboring portions 201 and 202 than to other portions. Further, it is preferable to apply an adhesive (for example, an acrylic adhesive) having low fluidity and capable of narrowing the coating width to the cut portion 200 and the neighboring portions 201 and 202. Further, the adhesive may be further applied only to the cut portion 200 and the neighboring portions 201 and 202 of the commercially available separator to which the adhesive is uniformly applied.

Next, with the separators 110a and 110b arranged on both sides of the uncut negative electrode sheet 100, the pre-cut negative electrode sheet 100 and the separators 110a and 110b are pressurized and heated by a heating type pressure roller. As a result, the negative electrode sheet 100 before cutting and the separators 110a and 110b are stretched, and the adhesive is melted. As a result, the uncut negative electrode sheet 100 and the separators 110a and 110b are adhered in a stretched state, and the uncut negative electrode sheet 100 and the separators 110a and 110b are integrated.

When the negative electrode sheet 100 before cutting and the separators 110a and 110b are adhered, the negative electrode sheet 100 before cutting and the separators 110a and 110b are heat-cut in the cutting step. In the cutting step, the heat-not-burn cutting blade is pressed against the pre-cutting negative electrode sheet 100 and the separators 110a and 110b so as to follow the cutting lines shown in FIGS. 1 and 2, so that the pre-cutting negative electrode sheet 100 and the separators 110a and 110b are pressed. Disconnect at virtually the same time. The temperature of the heat-not-burn cutting blade at the time of cutting is preferably a temperature at which the adhesive applied to the negative electrode sheet 100 and the separators 110a and 110b before cutting can be melted and the negative electrode sheet 100 and the separators 110a and 110b do not melt. ..

When the negative electrode sheet 100 before cutting and the separators 110a and 110b are cut by the heating type cutting blade, the negative negative sheet 100 and the separators 110a and 110b before cutting are cut by the shearing force applied by the heating type cutting blade, and the cutting portion 200 and the cutting portion 200 and The adhesive applied to the neighboring portions 201 and 202 is melted by the heat transferred from the heating type cutting blade. As a result, as shown in FIG. 2, the melted adhesive covers the cut surfaces 210 and 211 of the negative electrode sheet 100 and the separators 110a and 110b after cutting. After that, the adhesive solidifies as the temperature of the cut surfaces 210 and 211 decreases, and after cutting, the ends of the negative electrode sheet 100 and the separators 110a and 110b are covered with the solidified adhesive. In order to realize this, it is preferable to apply an adhesive in an amount capable of covering the cut surfaces 210 and 211 on the cut portions 200 and the vicinity portions 201 and 202 of the negative electrode sheet 100 before cutting and the separators 110a and 110b.

In the present embodiment, as shown in FIG. 1, the uncut negative electrode sheet 100 and the separators 110a and 110b wound around the reel 120, which is a rotary transfer device, are pulled out from the reel 120 and cut by heating. At this time, the negative electrode sheet 100 before cutting and the separators 110a and 110b are cut along a cutting line substantially perpendicular to the moving direction, and the two ends corresponding to the cut surfaces of the negative electrode sheet 100 and the separators 110a and 110b after cutting are formed. Aligned and coated with solidified adhesive. In FIG. 1, the negative electrode sheet 100 before cutting and the separators 110a and 110b wound on the reel 120 are pulled out from the reel 120 and cut, but the negative electrode sheet 100 before cutting and the separators 110a and 110b are not necessarily cut. It is not necessary to wind it around the reel 120. For example, in the bonding step, the negative electrode sheet before cutting 100 and the separators 110a and 110b are bonded by pressurizing and heating using two pressure type pressure rollers arranged one above the other, and then the negative electrode sheet before cutting is subsequently bonded. The 100 and the separators 110a and 110b may be cut by heating.

Next, an adhesive is applied to the contact surface between the post-cutting negative electrode sheet 100 and the separators 110a and 110b thus formed and the post-cutting positive electrode sheet formed by cutting the pre-cut positive electrode sheet to an appropriate size. , These are arranged so as to be laminated alternately. Then, the laminated positive electrode sheet after cutting, the negative electrode sheet 100 after cutting, and the separators 110a and 110b are pressurized and heated by a heating type pressure roller to form an electrode body included in the secondary battery of the present invention. ..

In the present invention, the size of the post-cut negative electrode sheet 100 is preferably larger than that of the post-cut positive electrode sheet in order to receive cations (lithium ions, hydrogen ions, etc.) released from the post-cut positive electrode sheet. Further, the separators 110a and 110b are preferably equal to or larger than the size of the negative electrode sheet 100 after cutting in order to prevent a short circuit of the electrode sheet. By making the size of the post-cut negative electrode sheet 100 and the separators 110a and 110b larger than the size of the post-cut positive electrode sheet, the post-cut negative electrode sheet 100 and the separators 110a and 110b are expanded regions that do not face the post-cut positive electrode sheet (hereinafter, It is referred to as an "extended area"), that is, it has an extended area that does not affect the storage of the secondary battery. In the method for manufacturing a secondary battery of the present invention, the negative electrode sheet 100 before cutting and the separators 110a and 110b are heat-cut in this extended region. Thereby, in the present invention, the following effects can be obtained without affecting the storage performance of the secondary battery.

In the present embodiment, since the negative electrode sheet 100 before cutting and the separators 110a and 110b are heat-cut in the cutting step, the adhesive applied to the cutting portion 200 and the neighboring portions 201 and 202 is melted, and after cutting with the melted adhesive. The negative electrode sheet 100 and the cut surfaces 210 and 211 of the separators 110a and 110b are coated. Then, the adhesive solidifies as the temperature of the cut surfaces 210 and 211 decreases, so that the cut surfaces 210 and 211 of the negative electrode sheet 100 and the separators 110a and 110b after cutting are covered with the solidified adhesive. .. Therefore, it is possible to prevent the end portion of the negative electrode sheet 100 from being exposed after cutting, and it is possible to prevent a short circuit due to contact with the positive electrode sheet after cutting. As a result, the effective area of the electrode sheet can be increased and the storage capacity of the secondary battery can be increased as compared with the method in which the areas of the separators 110a and 110b are made larger than the area of the negative electrode sheet 100 after cutting.

Further, in the present embodiment, in the bonding step, an adhesive is applied to at least one of the pre-cut negative electrode sheet 100 and the separators 110a and 110b, the pre-cut negative negative sheet 100 and the separators 110a and 110b are adhered, and then in the cutting step. , The uncut negative electrode sheet 100 and the separators 110a and 110b bonded with an adhesive are cut. As a result, the bonded state of the negative electrode sheet 100 and the separators 110a and 110b is maintained after cutting. Therefore, it is possible to prevent the separators 110a and 110b stretched by the pressure applied in the bonding step from shrinking after cutting. As a result, it is possible to prevent the surface of the negative electrode mixture layer of the negative electrode sheet 100 after cutting from being exposed, and it is possible to prevent a short circuit due to contact with the positive electrode sheet after cutting.

Further, the cut portion 200 and the vicinity portions 201, 202, that is, the region to which a large amount of adhesive is applied is preferably a part of the expansion region. Specifically, it is preferably a region within about 80% from the end of the expansion region, and more preferably a region within about 50% from the end of the expansion region. More adhesive than is required to bond the negative electrode sheet and the separator will be applied to this region. Generally, the adhesive causes an increase in the resistance of the battery, but since the positive electrode sheet and the negative electrode sheet do not face each other in the extended region, the influence of the adhesive on the battery resistance is small. Further, by applying the adhesive only to a part of the expansion region, the effect obtained by making the size of the negative electrode sheet larger than that of the positive electrode sheet (improvement of cation reception performance) is not lost.

<Other Embodiments of the present invention>
The present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the spirit. For example, in the above-described embodiment, the adhesive is applied or sprayed on all or a part of the contact surfaces of the pre-cut negative electrode sheet 100 and the separators 110a and 110b, but in other embodiments, the pre-cut negative electrode sheet 100 and the separator are used. The adhesive may be applied or sprayed only on the cut portions 200 and the vicinity portions 201 and 202 of 110a and 110b. As a result, the amount of the adhesive used can be reduced, and the man-hours required for applying or spraying the adhesive can be reduced.

Further, in another embodiment, the adhesive is applied to the pre-cut negative electrode sheet 100 and the separators 110a and 110b by arranging the adhesive sheet on all or part of the contact surfaces of the pre-cut negative electrode sheet 100 and the separators 110a and 110b. It may be attached. As a result, it is possible to prevent the adhesive from being applied or sprayed by the operator, and the quality of the product can be made uniform. In this case, it is preferable to dispose an adhesive sheet containing an amount of adhesive capable of covering the cut surfaces 210 and 211 with respect to the cut portions 200 and the neighboring portions 201 and 202 of the negative electrode sheet 100 before cutting and the separators 110a and 110b. .. For example, more adhesive sheets can be arranged on the cut portions 200 and the neighboring portions 201 and 202 of the uncut negative electrode sheet 100 and the separators 110a and 110b than on other portions.

Further, in another embodiment, instead of arranging the adhesive sheet on all or part of the contact surface of the pre-cut negative electrode sheet 100 and the separators 110a and 110b, the cut portion 200 of the pre-cut negative electrode sheet 100 and the separators 110a and 110b The adhesive sheet may be arranged only in the vicinity portions 201 and 202. As a result, the man-hours required for arranging the adhesive sheet and the amount of the adhesive sheet used can be reduced.

Further, in the embodiment shown in FIG. 1, the negative electrode sheet 100 before cutting and the separators 110a and 110b are heat-cut along a cutting line substantially perpendicular to the moving direction of the negative negative sheet 100 and the separators 110a and 110b. In the embodiment, as shown in FIG. 3, the pre-cut negative negative sheet 100 and the separators 110a and 110b are heated along the first cutting line substantially perpendicular to the moving direction of the pre-cut negative negative sheet 100 and the separators 110a and 110b. While cutting, the negative electrode sheet 100 before cutting and the separators 110a and 110b may be heat-cut along the second cutting line substantially perpendicular to the first cutting line. That is, the negative electrode sheet 100 before cutting and the separators 110a and 110b on the side where the current collector 101 does not exist may be heat-cut. A larger amount of adhesive than the other parts of the pre-cut negative electrode sheet 100 and the separators 110a and 110b is applied to the cut portion of the pre-cut negative electrode sheet 100 and the separators 110a and 110b corresponding to the second cutting line and the vicinity thereof. Is attached. As a result, the three ends corresponding to the cut surfaces of the post-cut negative electrode sheet 100 and the separators 110a and 110b, that is, the three ends of the post-cut negative electrode sheet 100 that do not include the current collector 101. Since the three ends of the separators 110a and 110b corresponding to this are aligned and covered with the solidified adhesive, these ends can be protected. Therefore, as compared with the method in which the areas of the separators 110a and 110b are made larger than the area of the negative electrode sheet 100 after cutting, the effective area of the electrode sheet can be increased and the storage capacity of the secondary battery can be increased. In this embodiment, in order to prevent a short circuit due to contact between the electrode sheets, the areas of the separators 110a and 110b are set to be larger than the area of the negative electrode sheet 100 after cutting only on the side where the current collector 101 exists. It is configured.

Further, in another embodiment, the negative electrode sheet 100 before cutting can be heat-cut together with the separators 110a and 110b even on the side where the current collector 101 exists. Specifically, as shown in FIG. 4, separators 110a and 110b are bonded from both sides in addition to the portion 102 corresponding to the current collector 101 in the negative electrode sheet 100 before cutting before the current collector 101 is formed. The negative electrode sheet 100 after cutting having the current collector 101 is formed by heating and cutting by punching. The laminated portion (that is, the cut portion) of the pre-cut negative electrode sheet 100 and the separators 110a and 110b to be punched and the portion in the vicinity thereof have a larger amount than the other portions of the pre-cut negative electrode sheet 100 and the separators 110a and 110b. Adhesive is attached. As a result, all the ends of the negative electrode sheet 100 and the separators 110a and 110b after cutting, except for the current collector 101, are covered with the solidified adhesive, so that these ends can be protected. it can. Therefore, the effective area of the electrode sheet can be increased and the storage capacity of the secondary battery can be increased as compared with the method of simply increasing the area of the separators 110a and 110b to be larger than the area of the negative electrode sheet 100 after cutting. ..

100 Negative electrode sheet 101 Current collector 110a, 110b Separator 120 Reel 200 Cutting part 201, 202 Near part 210, 211 Cut surface

Claims (12)

A secondary battery including an electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator that insulates the positive electrode sheet and the negative electrode sheet are laminated.
The negative electrode sheet and the separator are at least partially adhered with an adhesive in a state where the separator is laminated on both sides of the negative electrode sheet.
A secondary battery, characterized in that the negative electrode sheet and at least one end of the separator are coated with an adhesive in an aligned state. The first aspect of the present invention, wherein a larger amount of the adhesive is attached to the portion near the end portion of the negative electrode sheet and the separator than to the other portions of the negative electrode sheet and the separator. Secondary battery. Of the four ends of the negative electrode sheet, two ends that do not include a current collector and the corresponding two ends of the separator are covered with an adhesive in an aligned state. The secondary battery according to claim 1 or 2. Of the four ends of the negative electrode sheet, three ends that do not include a current collector and the corresponding three ends of the separator are coated with an adhesive in an aligned state. The secondary battery according to claim 1 or 2. Of the four ends of the negative electrode sheet, three ends not including the current collector and the corresponding three ends of the separator are coated with an adhesive in an aligned state.
1. The remaining end portion of the negative electrode sheet, the portion other than the current collector portion, and the end portion of the separator corresponding thereto are coated with an adhesive in an aligned state, according to claim 1 or The secondary battery according to 2. The size of the negative electrode sheet and the separator is larger than the size of the positive electrode sheet, and the negative electrode sheet and the separator have an expansion region that does not face the positive electrode sheet.
The invention according to any one of claims 1 to 5, wherein a larger amount of the adhesive than the negative electrode sheet and the other parts of the separator is applied to at least a part of the expansion region. The described secondary battery. A method for manufacturing a secondary battery including an electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator that insulates the positive electrode sheet and the negative electrode sheet are laminated.
The first step of applying an adhesive to at least one of the negative electrode sheet and the separator, and
A second step of arranging the two separators on both sides of the negative electrode sheet and adhering the negative electrode sheet and the separator with the adhesive.
A method for manufacturing a secondary battery, comprising a third step of heat-cutting the negative electrode sheet and the separator bonded with the adhesive and coating the cut surface of the negative electrode sheet and the separator with the adhesive. The first step is characterized in that an amount of an adhesive capable of covering the cut surface is applied to the negative electrode sheet, the cut portion which is the cut portion of the separator, and the vicinity portion of the cut portion. The method for manufacturing a secondary battery according to claim 7. 2. The second step according to claim 8, wherein in the first step, a larger amount of adhesive is applied to the cut portion and the nearby portion than to the negative electrode sheet and the other portions of the separator. How to manufacture the next battery. The method for manufacturing a secondary battery according to claim 8, wherein in the first step, the adhesive is applied only to the cut portion and the vicinity portion. The method for manufacturing a secondary battery according to any one of claims 7 to 10, wherein in the third step, the negative electrode sheet and the separator on the side where the current collector does not exist are heated and cut. .. The production of the secondary battery according to any one of claims 7 to 10, wherein in the third step, the negative electrode sheet other than the portion corresponding to the current collector is heat-cut together with the separator. Method.

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