JP2021005457A - Electrochemical cell and manufacturing method of the same - Google Patents

Abstract

To provide an electrochemical cell in the present invention.SOLUTION: An electrochemical cell of the present invention, comprises an electrode lamination body which is formed by wounding an arbitrary winding center axis so as to be circulated via a separator layer formed by a coating hardening layer in which at least one surface is coated in at least of a band-shaped positive electrode body and a band-shaped negative electrode body, is provided with an inner side container having an outer peripheral wall and an outer side container having the outer peripheral wall, and is characterized in that the electrode lamination body is housed in an outer casing body in which the outer peripheral wall of the inner side container is overlapped with the outer peripheral wall of the outer side container, is folded and fused, and is integrated.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrolytic chemical cell and a method for producing the same.

Conventionally, electrochemical cells such as lithium ion secondary batteries and electrochemical capacitors have been widely used as a power source for small devices such as smartphones, wearable devices, and hearing aids.
In such an electrochemical cell, it is necessary to increase the area of the electrodes facing each other in the electrochemical cell as much as possible from the viewpoint of increasing the battery capacity and the charging current and the discharging current. As a structure of an electrochemical cell, a structure in which a pair of strip-shaped positive electrodes and negative electrodes are wound around a band-shaped separator and housed in a case, and an electrolytic solution is sealed in the case is known.

For example, as a porous separator for a battery, Patent Document 1 below describes a step of printing a thin layer of a separator precursor on an electrode and a step of vulcanizing this thin layer to change it into a microporous composite separator structure. A manufacturing method comprising the above is disclosed.
In Patent Document 2 below, the voids between the polymer solid electrolyte obtained by impregnating the stretched porous PTFE (polytetrafluoroethylene) with a polymer solid electrolyte resin solution and then removing the solvent, and the stretched porous PTFE. A composite polymer solid electrolyte membrane / electrode integrally molded body in which an electrode catalyst and an electrode filled with an electrode component containing a polymer solid electrolyte are integrally molded is described.
Further, as described in Patent Document 3 below, an electrode is formed by winding a band-shaped positive electrode and a negative electrode via a sheet-shaped separator, and this electrode is placed inside an exterior body composed of a positive electrode side container and a negative electrode side container. The housed button-type electrochemical cell is known.

Japanese Unexamined Patent Publication No. 10-334877 Japanese Unexamined Patent Publication No. 08-329962 Japanese Unexamined Patent Publication No. 2016-100122

In the configuration described in Patent Document 3, the outer body accommodating the electrode wound around the strip-shaped positive electrode and the negative electrode is composed of a positive electrode side container and a negative electrode side container having a laminated structure in which resin layers are laminated on both sides of a metal foil such as aluminum. The exterior body is used. Further, the joint portion between the positive electrode side container and the negative electrode side container is formed by press working so that the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and bent while being overlapped.

However, when the outer peripheral wall of the container having a laminated structure is bent by press working, the resin layer is stretched together with the metal foil. Therefore, if the resin layer has defects, the resin layer has defects such as pinholes, cracks, and streaks. May cause parts.
If these defective portions are formed on the outer peripheral wall of the inner container, the electrolytic solution sealed in the container may come into contact with the metal foil. When the above-mentioned electrochemical cell is a lithium ion battery and the metal foil is aluminum, aluminum may be alloyed with lithium at the negative electrode side potential, so that the negative electrode potential may accelerate the deterioration of aluminum. It was.

Further, in a container having a laminated structure, the outer resin layer is tough and a resin such as nylon having a high melting point is applied. Nylon has a high hydrophilicity and has a property of swelling when it contains water. If the outer resin layer loses the volume change due to swelling and cracks occur, the sealed portion may deteriorate.
In particular, in the case of a coin-type electrochemical cell, since the internal volume is small, the distance between the current collector foil constituting the electrode and the outer peripheral wall of the container is narrow, and there is a problem that an internal short circuit is structurally likely to occur. For example, when a band-shaped positive electrode and a negative electrode are wound around a sheet-shaped separator to form an electrode, if any winding deviation occurs, the electrode may protrude to the outside of the separator and an internal short circuit may occur.

The present invention has been made in view of the conventional circumstances as described above, and in the case of an electrochemical cell in which a band-shaped positive electrode and a negative electrode are wound to form an electrode, the occurrence of a short-circuit risk is suppressed and the manufacturing process is performed. An object of the present invention is to provide an electrochemical cell capable of improving the yield and a method for manufacturing the same.

(1) In the present invention, the positive electrode body and the negative electrode body are wound at an arbitrary center via a separator layer composed of a coating film curing layer covering at least one surface of at least one of the band-shaped positive electrode body and the band-shaped negative electrode body. It is provided with an electrode laminate formed by winding around a shaft, and is composed of an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, and the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and bent. The electrode laminate is housed in a fused and integrated exterior body.

(2) In the present invention, the positive electrode body and the negative electrode body are wound at an arbitrary center via a separator layer composed of a coating film cured layer covering at least one surface of at least one of the band-shaped positive electrode body and the band-shaped negative electrode body. The electrode laminate is provided by winding it around a shaft, and the electrode laminate is housed in an exterior body in which a positive electrode can and a negative electrode can are integrated via a gasket.

In the case of an electrode laminate having a structure in which a positive electrode body and a negative electrode body having a separator layer composed of a coating film cured layer are wound, the separator layer reliably insulates and separates the positive electrode body and the negative electrode body. It is possible to provide an electrolytic chemical cell with less risk of short circuit even if the body is miswound.
On the other hand, in the structure in which the tape-shaped separator is wound together with the positive electrode body and the negative electrode body, when the positive electrode body or the negative electrode body is unwound, a part of the electrode body protrudes from the separator layer, so that an internal short circuit occurs. May pose a risk. Simply increasing the separator to avoid the risk of internal shorts reduces the battery capacity density per volume as an electrical cell. Therefore, an electrochemical cell in which a positive electrode body and a negative electrode body provided with a separator layer made of a coating film cured layer are wound can provide an electrochemical cell that does not cause a decrease in battery capacity density per volume.

(3) In the electrochemical cell according to one embodiment of the present invention, the coating film cured layer provided on both the front and back surfaces of the band-shaped positive electrode body and the peripheral surface including the front and back surfaces and the side surface of the band-shaped negative electrode body is fused and integrated in the wound state. It is preferable that a modified separator layer is provided.

If the separator layer is formed by integrating a coating film curing layer that individually covers the peripheral surface of the positive electrode body and the peripheral surface of the negative electrode body, it may be part of the positive electrode body and the negative electrode body when the positive electrode body and the negative electrode body are wound. Even if the winding is disturbed, the positive electrode body and the negative electrode body are surely covered with the separator layer. Further, the outer peripheral surface of the electrode laminate around which the positive electrode body and the negative electrode body are wound is also surely covered with the separator layer. As a result, it is possible to provide an electrochemical cell that does not cause an internal short circuit.

(4) In the electrochemical cell according to one embodiment of the present invention, an extension portion is formed on the positive electrode body and a part of the negative electrode body, and the extension portion on the positive electrode side and the extension portion on the negative electrode side are extended. It is preferable that a connection tab is formed on the tip end side of the portion so that the separator layer made of the coating film curing layer is not formed.

By connecting the connection tab on the positive electrode side to the positive electrode terminal on one container side and the connection tab on the negative electrode side to the negative electrode terminal on the other container side, the terminal on the container side does not use a separate tab for conduction. The positive electrode body and the negative electrode body can be connected to. Therefore, the tab for conduction can be omitted, and the electrode can be arranged in the space where the tab for conduction is provided, so that an electrochemical cell having a high battery capacity density per volume can be provided.

(5) In the electrochemical cell according to one embodiment of the present invention, it is preferable that the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are made of a laminated structure in which resin layers are provided on both sides of the metal foil.

In the case of an exterior body made of a laminated structure containing a metal foil, the metal foil portion can prevent the intrusion of moisture, and an electrochemical cell without a risk of moisture intrusion from the outside can be provided on the inner side of the exterior body. ..
Further, even if defects such as pinholes, tears, and streaks occur in the resin layer, the metal foil of the exterior body may come into contact with the electrolytic solution, and further, even if there is a risk of contact with the electrode laminate side, the electrode laminate and the electrode laminate Since a separator layer made of a coating film curing layer can be reliably interposed between the metal foil and the metal foil, there is no risk of applying an electric potential to the metal foil, and it is possible to provide a structure in which deterioration of the metal foil is unlikely to occur.

(6) In the electrochemical cell according to one embodiment of the present invention, the band-shaped positive electrode body and the band-shaped negative electrode body are both a plurality of electrode bodies having a plan view shape similar to the plan view shape of the exterior body. , The electrode connecting portion for connecting the plurality of electrode bodies is provided, and the positive electrode body and the negative electrode body are spirally wound and integrated with each other via the coating film curing layer, and the electrode body of the positive electrode body is integrated. It is preferable that the electrode connecting portion, the electrode main body of the negative electrode body, and the electrode connecting portion are all covered with a separator layer made of the coating film cured layer.

If the positive electrode body and the negative electrode body are provided with a plurality of electrode bodies having a plan view shape similar to the plan view shape of the exterior body, and the plurality of electrode bodies are connected via a plurality of electrode connection portions, the electrode body on the positive electrode side and the electrode body are connected. By winding the electrode bodies on the negative electrode side in a spiral shape while overlapping them, an electrochemical cell equipped with an electrode laminate having a shape that matches the outer shape of the exterior body can be accommodated at high density without gaps inside the exterior body. Can be provided. By covering both the electrode body and the electrode connection portion with the separator layer, the entire electrode laminate is covered with the separator layer, and an electrochemical cell with less risk of short circuit can be provided.

(7) In the electrochemical cell according to one embodiment of the present invention, it is preferable that both the electrode body and the electrode connecting portion are provided with active material layers on both the front and back surfaces of a current collector layer made of a metal foil.

As a specific structure of the positive electrode body and the negative electrode body, a positive electrode body or a negative electrode body having a structure in which active material layers are provided on both the front and back surfaces of a current collector layer made of a metal foil can be applied. If the separator layer is composed of a coating and curing layer, the entire positive electrode body and negative electrode body can be reliably covered even with a laminated structure of the current collector layer and the active material layer provided on the current collector layer. Therefore, for example, it is possible to provide an electrochemical cell having a structure in which the positive electrode body and the negative electrode body are surely covered with a separator layer even if the positive electrode body and the negative electrode body are unwound during winding.

(8) In the electrochemical cell according to one embodiment of the present invention, the positive electrode body and the negative electrode body are connected to each other via a separator layer composed of a coating film curing layer covering at least one surface of at least one of the positive electrode body and the negative electrode body. The exterior is provided with an electrode laminate formed by laminating, and is composed of an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, and the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and bent, fused and integrated. It is characterized in that the electrode laminate is housed in the body.

If the outer body is fused and integrated by overlapping and bending the outer peripheral wall of the inner container and the outer peripheral wall of the outer container, the adhesion of the joint where the inner container and the outer container are fused is good, and the sealing property is improved. It can provide an excellent exterior body.

(9) The method for producing an electrochemical cell according to the present invention is the method for producing an electrochemical cell according to any one of (1), (3) to (7), wherein a strip-shaped positive electrode body and a strip-shaped positive electrode are formed. After forming a curable coating film on at least one surface of at least one of the negative electrode bodies, the positive electrode body and the negative electrode body are wound around the positive electrode body in a semi-cured state to form an electrode laminate, and the electrodes are formed. It is characterized in that the semi-cured coating film is cured after the laminated body is housed inside the exterior body and the shape of the exterior body is adjusted.

By winding a positive electrode body and a negative electrode body having a semi-cured coating film on the peripheral surface to form an electrode laminate, the semi-cured coating films existing in the portions where the positive electrode body and the negative electrode body are in contact with each other are brought into contact with each other. It can be wound while being integrated. By accommodating the electrode laminate having the semi-cured coating film adhered in this way inside the exterior body and completely curing the semi-cured coating film from the state in which the shape of the exterior body is adjusted, as a whole. It is possible to obtain an electrochemical cell having a well-shaped state and a structure in which the entire electrode laminate is covered with a separator layer.
In particular, when the exterior body is a laminated structure of a metal foil and a resin layer, the exterior body is flexible in a state where the electrode laminate is housed, and the presence of a semi-cured coating film is also present, so that electrochemical is used. Although the overall shape of the cell is not solidified, it is possible to provide an electrochemical cell having a well-shaped and strong structure by completely curing the coating film after adjusting the shape of the exterior body.

According to the present invention, if the electrode laminate has a structure in which a positive electrode body and a negative electrode body having a separator layer composed of a coating film cured layer are wound, the positive electrode body and the negative electrode body can be reliably separated by insulation by the separator layer. It is possible to provide an electrolytic chemical cell with less risk of short circuit even if the negative electrode body is miswound.

It is a perspective view which made a part of the secondary battery (electrochemical cell) of 1st Embodiment which concerns on this invention a cross section. It is a perspective view which shows the electrode laminated body formed by winding a positive electrode body and a negative electrode body with a separator layer. It is a top view which shows the developed state of the positive electrode body and the negative electrode body which make up the electrode laminated body. It is a top view which shows the state which removed the separator layer from the positive electrode body and the negative electrode body shown in FIG. It is a perspective view which made a part of the secondary battery (electrochemical cell) of 2nd Embodiment which concerns on this invention a cross section. The electrode laminate housed in the secondary battery of the second embodiment is shown, (A) is a front view showing an example of a negative electrode side current collector layer, and (B) is a separator layer on the current collector layer. (C) is a front view showing an example of a positive electrode side current collector layer, (D) is a plan view showing a state in which the current collector layer is covered with a separator layer, (E). Is a perspective view showing an electrode laminate. It is sectional drawing of the secondary battery (electrochemical cell) of 3rd Embodiment which concerns on this invention. It is a perspective view which made a part of the secondary battery of the 3rd Embodiment as a cross section.

Hereinafter, embodiments of the electrodes according to the present invention will be described with reference to the drawings. In the following embodiment, a coin-type lithium ion secondary battery (hereinafter, simply referred to as “battery”) is given as an example of an electrochemical cell, and an electrode mounted on the battery will be described.
In the drawings used in the following description, the scale of each member is appropriately changed in order to make each member recognizable.

<First Embodiment>
FIG. 1 is a partial cross-sectional view showing a first embodiment in which the electrolytic chemical cell according to the present invention is applied to a secondary battery.
The battery 1 of the present embodiment is a button-type battery having a circular shape in a plan view. The battery 1 includes a container-shaped exterior body 2 and an electrode laminate 3 housed inside the exterior body 2. Although omitted in FIG. 1, the outer body 2 is filled with an electrolytic solution. As the electrolytic solution, an electrolytic solution in which a supporting salt is dissolved in a non-aqueous solvent is preferably used.

(Exterior body)
The exterior body 2 includes an accommodating portion 4 for accommodating the electrode laminate 3, and a sealing portion 5 bent along the outer circumference 4a of the accommodating portion 4. The sealing portion 5 is formed by being bent along the outer peripheral 4a of the accommodating portion 4 by, for example, drawing.
The outer body 2 includes a first container (outer container) 10 and a second container (inner container) 20 that sandwich the electrode laminate 3 in between. The first container 10 and the second container 20 are each formed of a laminated structure (laminated film). The laminated structure includes a metal foil (metal layer), a fusion layer (resin layer) provided on the overlapping surface (inner side surface) and covering the metal foil, and a protective layer provided on the outer surface and covering the metal foil (the protective layer). It has a resin layer). The metal layer is made of, for example, aluminum or stainless steel, and is formed of a metal foil that blocks outside air and water vapor. The fused layer of the overlapping surface is formed of, for example, a simple substance or a copolymer of a thermoplastic resin such as polyethylene or polypropylene of polyolefin. The protective layer on the outer side surface is formed of, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

The first container 10 includes a circular first bottom wall portion 11 and a first peripheral wall portion 12 extending in a tubular shape from the outer periphery of the first bottom wall portion 11. A first through hole 13 is formed in the center of the first bottom wall portion 11.
On the inner surface of the first bottom wall portion 11, a negative electrode plate 15 in which a copper plate or a nickel plate or the like is integrated with the copper plate is heat-sealed via a first sealant ring 14. The first sealant ring 14 is a ring-shaped sealant film formed by using a thermoplastic resin such as polyolefin polyethylene or polypropylene.

The inner surface of the negative electrode plate 15 is connected to a connection tab 35 (see FIG. 2) of the negative electrode body 30 described later in the electrode laminate 3. A wear-resistant plate such as a nickel plate is preferably welded to the center of the outer surface of the negative electrode plate 15. The negative electrode plate 15 penetrates the first through hole 13 and is exposed to the outside, and functions as a negative electrode terminal of the battery 1. If the negative electrode plate 15 is made of nickel or a nickel alloy, the nickel plate may be omitted.

The second container 20 has a circular second bottom wall portion 21, a second peripheral wall portion 22 extending in a tubular shape from the outer peripheral edge of the second bottom wall portion 21, and a second peripheral wall from the opening edge of the second peripheral wall portion 22. A bent portion 23 that is bent toward the outside of the portion 22 so as to have a U-shaped cross section and extends toward the second bottom wall portion 21 is provided.
The second bottom wall portion 21 is arranged on the opposite side of the first container 10 from the first bottom wall portion 11 with the electrode laminate 3 interposed therebetween. The second bottom wall portion 21 is formed to have an outer diameter equivalent to that of the first bottom wall portion 11 of the first container 10. A second through hole 24 is formed in the center of the second bottom wall portion 21.

In the structure of FIG. 1, since the outer diameters of the first peripheral wall portion 12 and the second peripheral wall portion 22 are the same, the diameter of the first peripheral wall portion 12 is slightly smaller than that of the end portion on the second peripheral wall portion 12 side via the step portion 12a. An enlarged connecting peripheral wall 12b is formed, and the connecting peripheral wall 12b is joined to the outside of the second peripheral wall portion 22.
When the outer diameter of the first peripheral wall portion 12 is formed to be the same as the outer diameter of the connecting peripheral wall portion 12b, the step portion 12a and the connecting peripheral wall portion 12b are omitted, and the opening side of the first peripheral wall portion 12 is directly connected to the second peripheral wall portion. It may be externally attached to the portion 22.

A positive electrode plate 26 made of aluminum or the like is heat-sealed on the inner surface of the second bottom wall portion 21 via a second sealant ring 25. The second sealant ring 25 is made of a thermoplastic resin like the first sealant ring 14.
The inner surface of the positive electrode plate 26 is connected to a connection tab 45 (see FIG. 2) of the positive electrode body 40, which will be described later, of the electrode laminate 2. It is preferable that a plate having low contact resistance such as a nickel plate is welded to the center of the outer surface of the positive electrode plate 26. The nickel plate in this case penetrates the second through hole 24 and is exposed to the outside, and functions as a positive electrode terminal of the battery 1. For example, instead of the positive electrode plate 26 made of aluminum, a positive electrode plate made of stainless steel or the like can be used.

The second peripheral wall portion 22 extends in a tubular shape from the outer periphery of the second bottom wall portion 21 toward the first bottom wall portion 11 of the first container 10. The second peripheral wall portion 22 forms the outer circumference 4a of the accommodating portion 4. The bent portion 23 is bent so as to form a tubular shape from the end portion on the first bottom wall portion 11 side of the second peripheral wall portion 22 toward the second bottom wall portion 21 along the second peripheral wall portion 22. There is. The bent portions 23 are arranged at intervals on the outside with respect to the second peripheral wall portion 22.
The second peripheral wall portion 22 is arranged inside the connecting wall 12b of the first peripheral wall portion 12 and inside the bent portion 23. Further, the bent portion 23 is arranged inside the connecting wall 12b of the first peripheral wall portion 12, and the fusion layer of the bent portion 23 and the fusion layer of the connecting wall 12b are heat-sealed.

The sealing portion 5 is formed by fusing the fusion layer of the bent portion 23 and the fusion layer of the connecting wall 12b by ultrasonic waves, heating, or the like. Therefore, the outer circumference of the accommodating portion 4 is sealed by the sealing portion 5. With the above structure, the first container 10 and the second container 20 are overlapped and joined to form the exterior body 2. The sealing portion 5 is formed in a tubular shape on the outside of the accommodating portion 4, and is bent along the outer circumference 4a of the accommodating portion 4.
A sealed space is formed in the accommodating portion 4 by superimposing the first container 10 and the second container 20. Specifically, the accommodating portion 4 is defined by the first bottom wall portion 11, the second bottom wall portion 21, and the second peripheral wall portion 22, and is formed in a circular shape in a plan view.

(Electrode laminate)
FIG. 2 is a perspective view showing the electrode laminate 3 of the first embodiment, and the electrode laminate 3 is a negative electrode body 30 and a positive electrode side separator layer coated with a negative electrode side separator layer 36 as shown in FIG. It is composed of a positive electrode body 40 coated with 46.
The electrode laminate 3 is an electrode laminate that is folded so that the negative electrode body 30 and the positive electrode body 40 are alternately laminated. Specifically, the electrode laminate 3 is formed by superimposing the negative electrode body 30 and the positive electrode body 40 via the separator layers 36 and 46 and winding them in a flat shape as shown in FIG. The negative electrode body 30 is connected to the negative electrode plate 15 described above, and the positive electrode body 40 is connected to the positive electrode plate 26 described above.

The negative electrode side separator layer 36 is formed so as to cover the entire negative electrode body 30 except for the tip end portion of the connection tab 35 described later. The positive electrode side separator layer 46 is formed so as to cover the entire negative electrode body 40 except for the tip end portion of the connection tab 45 described later.
Therefore, the separator layers 36 and 46 are arranged around the negative electrode body 30 and the positive electrode body 40 and between these layers in a state where the negative electrode body 30 and the positive electrode body 40 are wound around, and the negative electrode body 30 and the positive electrode body 40 are insulated from each other. Be separated. In FIG. 2, only the position where the negative electrode side separator layer 36 exists is shown ignoring the layer thickness, and the positive electrode side separator 46 is not shown. However, the separators 36 and 46 are at least the negative electrode body 30 and the positive electrode body. The positive electrode side separator layer 46 is the positive electrode body 40 so as to be interposed between the negative electrode body 30 and the positive electrode body 40 in the entire region facing the 40, and so that the negative electrode side separator layer 36 covers the negative electrode body 30. It is arranged so as to cover.
Hereinafter, the direction in which the negative electrode body 30 and the positive electrode body 40 are wound and laminated is referred to as a lamination direction. In addition, winding means winding so as to orbit around a specific winding central axis.

The negative electrode body 30 is a sheet-like member including a foil-shaped negative electrode current collector formed of a metal material and a negative electrode active material layer coated on one or both sides of the negative electrode current collector. The negative electrode current collector is formed of, for example, a metal foil such as copper or stainless steel. The thickness of the metal foil is, for example, about several μm. The negative electrode active material is, for example, a simple substance or a mixture of silicon, silicon oxide, graphite, hard carbon, lithium titanate and the like.
As a material for forming the negative electrode active material layer, in addition to the negative electrode active material, a conductive auxiliary agent (for example, graphite), a binder (for example, a dispersion of polyvinylidene fluoride or styrene-butadiene rubber (SBR)), and a thickener (for example, a thickener). , Carboxymethyl cellulose (CMC), etc.) and a solvent (for example, any solvent such as N-methylpyrrolidone) can be mixed to prepare a slurry for a negative electrode. A coating liquid containing a constituent material for forming the negative electrode active material layer can be referred to as a “negative electrode slurry”. The negative electrode active material layer can be formed by applying this negative electrode slurry to the negative electrode side current collector and drying it.

The positive electrode body 40 is a single sheet-like member including a foil-shaped positive electrode current collector formed of a metal material and a positive electrode active material layer coated on one or both sides of the positive electrode current collector. is there. The positive electrode current collector is formed of, for example, a metal foil such as aluminum or stainless steel. The thickness of the metal foil is, for example, about 10 μm. The positive electrode active material is a composite oxide containing lithium and a transition metal, such as lithium cobalt oxide, lithium titanate, and lithium manganate.
As a material for forming the positive electrode active material layer, in addition to the above-mentioned positive electrode active material, a conductive additive (for example, graphite, etc.), a binder (for example, polyvinylidene fluoride, etc.), a solvent (for example, any solvent such as N-methylpyrrolidone). Can be mixed to prepare a slurry for a positive electrode. A coating liquid containing a constituent material for forming a positive electrode active material layer can be referred to as a “positive electrode slurry”. The positive electrode active material layer can be formed by applying this positive electrode slurry to the positive electrode side current collector and drying it.

The separator layers 36 and 46 are resin layers having lithium ion conductivity as an example.
The separator layers 36 and 46 are composed of a resin layer formed by applying the following paints to necessary parts of the negative electrode body 30 and the positive electrode body 40 to form a coating film and curing the coating film.

As the coating material for forming the separator layers 36 and 46, for example, polyethylene oxide (PEO), polypropylene oxide (PPO), or a copolymer thereof and a lithium salt added as a supporting salt to the electrolytic solution are added to a solvent such as acetonitrile. A paint dissolved in is used. Further, even if the coating material itself does not have lithium ion conductivity, a material that can impart ion conductivity by moistening the electrolytic solution may be used. For example, polyvinylidene fluoride (PVDF) or polyvinylidene fluoride-hexafluoropropylene may be used. A solution obtained by dissolving (PVDF-HFP) and a lithium salt added as a supporting salt to the electrolytic solution in a solvent such as acetone or N-methyl-2-pyrrolidone (NMP) may be used.
Further, ionic conductivity may be imparted by mixing an inorganic substance with the resin contained in the paint. In that case, the inorganic substance itself may have ionic conductivity, but the layer formed at the interface between the inorganic substance and the resin may exhibit ionic conductivity.
As the inorganic substance to be added, a simple substance or a mixture of aluminum oxide powder, titanium oxide powder, silicon oxide powder, zinc oxide powder and magnesium oxide powder can be mixed and used in various formulations. At this time, the particle size of the inorganic substance is preferably 5 nm to 1 μm.
After applying these paints to form a coating film, the solvent is blown off by means such as heating, light irradiation, and drying to cure the coating film, whereby the separator layers 36 and 46 can be formed. Further, in order to reinforce the strength of the separator layers 36 and 46, it is also effective to simultaneously dissolve inorganic or organic granular or filler-like powder in the paint.

As shown in FIG. 1, the electrode laminate 3 is formed in a shape corresponding to the shape of the sealed space in the housing portion 4 so as to be arranged at a high density in the housing portion 4 of the exterior body 2 ( (See FIG. 1). That is, the electrode laminate 3 is formed in a circular shape when viewed from the stacking direction. The shape of the electrode laminate 3 viewed from the stacking direction is defined as the basic shape.

Here, the shapes of the negative electrode body 30 and the positive electrode body 40 in the deployed state of the electrode laminate 3 will be described.
FIG. 3 is a plan view showing the expanded state of the negative electrode body 30 and the positive electrode body 40 of the first embodiment provided with the separator layer, and FIG. 4 is the expanded state of the negative electrode body 30 and the positive electrode body 40 excluding the separator layer. It is a top view which shows.
As shown in FIGS. 3 and 4, the negative electrode body 30 connects a plurality of (8 in the illustrated example) substantially circular negative electrode bodies 31 arranged side by side in a row and a pair of adjacent negative electrode bodies 31. It is provided with at least one electrode connecting portion (7 in the illustrated example) and a negative electrode tab 35 extending from the negative electrode main body 31. The negative electrode body 31 is a portion of the electrode laminate 3 that extends flat along a plane orthogonal to the lamination direction (see FIG. 2).
The electrode connecting portion 32 is a portion that is folded back at the side portion of the laminated electrode body 2 so that the plurality of negative electrode bodies 31 overlap each other during lamination (see FIG. 2). The negative electrode tab 35 is a portion connected to the negative electrode plate 15 described above. A negative electrode active material layer coated with a negative electrode active material is formed on the front and back surfaces of the negative electrode main body 31 and the electrode connecting portion 32, respectively. The negative electrode active material layer is not applied to the front and back surfaces of the tip of the negative electrode tab 35, and the negative electrode current collector is exposed.

Hereinafter, the direction in which the plurality of negative electrode bodies 31 are lined up is referred to as a negative electrode connecting direction (first direction), and the direction orthogonal to the negative electrode connecting direction is referred to as a negative electrode width direction. Further, in the negative electrode connecting direction, the negative electrode main body 31 side arranged on the outer peripheral side of the electrode laminated body 3 is opposed to the negative electrode main body 31 arranged on the most winding center side of the electrode laminated body 3 among the plurality of negative electrode main bodies 31. It is defined as "outer circumference side", and the opposite direction is defined as "inner circumference side". Further, in the following, the plurality of negative electrode main bodies 31 will be described with ordinal numbers in order from the innermost peripheral negative electrode main body 31 to the outer peripheral side. In other words, N is a natural number, and the Nth negative electrode body counted from the innermost negative electrode body 31 to the outer peripheral side is referred to as the Nth negative electrode body. For example, the innermost peripheral negative electrode body 31 is the first negative electrode body. The same applies to the plurality of electrode connection portions 32.

The plurality of negative electrode bodies 31 are arranged so that the centers in the negative electrode width direction are overlapped with each other when viewed from the negative electrode connecting direction. The plurality of negative electrode bodies 31 are formed in a shape in which a part of a circle is missing. The negative electrode body 31 excluding the eighth negative electrode body 31H arranged on the outermost periphery of the negative electrode body 31 has the entire straight portion 33 in the negative electrode connecting direction so as to gradually reduce the dimension in the negative electrode connecting direction with respect to the above basic shape. Is provided closer to the central axis with respect to the above basic shape.

The plurality of electrode connecting portions 32 are provided between a pair of negative electrode main bodies 31 adjacent to each other in the negative electrode connecting direction. Each electrode connecting portion 32 is formed so that the intermediate portion in the negative electrode connecting direction has the narrowest width. The intermediate portion means not only the center between both ends of the target but also the inner range between both ends of the target. The outer edges of the electrode connecting portion 32 on both sides in the negative electrode width direction extend in an arc shape recessed in the negative electrode width direction. The dimensions of the plurality of electrode connecting portions 32 in the negative electrode connecting direction increase as the distance from the first electrode connecting portion 32A arranged on the innermost circumference increases. In other words, the plurality of electrode connecting portions 32 are formed so as to be gradually larger in the negative electrode connecting direction than the electrode connecting portions 32 adjacent to the inner peripheral side.

The negative electrode tab 35 extends from the eighth negative electrode body 31H to the side opposite to the first negative electrode body 31A. The negative electrode tab 35 extends in the negative electrode connecting direction with a width narrower than that of the plurality of electrode connecting portions 32.
In the negative electrode body 30 having the above configuration, the entire portion of the negative electrode tab 35 except the tip end side is covered with the negative electrode side separator layer 36 (see FIG. 3). That is, in addition to the front and back surfaces of the negative electrode body 31, the peripheral surface (side surface) and the front and back surfaces of the electrode connecting portion 32 and the side surface are covered with the negative electrode side separator layer 36.

As described above, the negative electrode side separator layer 36 is formed by curing the coating film. When the paint is applied to the front and back surfaces of the negative electrode body 30 shown in FIG. 4 except for the tip end side of the negative electrode tab, the paint can wrap around on the peripheral surface side (peripheral end surface side) of the negative electrode body 30. The negative electrode side separator layer 36 can be formed so as to cover almost the entire negative electrode body 30 except for the tip portion of the negative electrode tab 35.
As for the paint, after forming the coating film, if a paint that cures by heat is used, it is heated to the curing temperature, and if a paint that cures by irradiation with light such as ultraviolet rays is used, light of the wavelength required for curing is required. In the case of a paint that is irradiated with intensity and cured by drying, the paint can be cured by drying at an appropriate temperature. By curing the paint, a negative electrode body 30 having a structure covered with the separator layer 36 can be obtained as shown in FIG.

Next, the shape of the positive electrode body 40 in the expanded state of the electrode laminate 3 will be described.
As shown in FIGS. 3 and 4, the positive electrode body 40 is at least one (8) connected to a plurality of (8 in the illustrated example) positive electrode bodies 41 arranged side by side in a row and a pair of adjacent positive electrode bodies 41. In the illustrated example, it has 7) electrode connection portions 42 and a positive electrode tab 45 extending from the positive electrode body 41.
The positive electrode body 41 is a portion of the electrode laminate 3 that extends flat along a vertical plane in the stacking direction. The electrode connecting portion 42 is a portion that is folded back at the side portion of the laminated electrode body 2 so that the plurality of positive electrode main bodies 41 overlap the negative electrode main body 31. The positive electrode tab 45 is a portion connected to the positive electrode plate 26 described above. A positive electrode active material layer coated with the positive electrode active material is formed on the entire surface of each of the positive electrode main body 41 and the electrode connecting portion 42. A positive electrode current collector is exposed on the surface of the tip of the positive electrode tab 45.

Hereinafter, the direction in which the plurality of positive electrode bodies 41 are lined up is referred to as the positive electrode connecting direction (second direction), and the direction orthogonal to the positive electrode connecting direction is referred to as the positive electrode width direction. Further, in the positive electrode connecting direction, the positive electrode main body 41 arranged on the outer peripheral side of the electrode laminated body 3 is "" with respect to the positive electrode main body 41 arranged on the most winding center side of the laminated electrode body among the plurality of positive electrode main bodies 41. It is defined as "outer circumference side", and the opposite direction is defined as "inner circumference side". Further, in the following, the plurality of positive electrode main bodies 41 and the plurality of electrode connecting portions 42 will be described with ordinal numbers in the same manner as the negative electrode main body 31 and the electrode connecting portions 32.

The plurality of positive electrode main bodies 41 are provided in the same number as the negative electrode main bodies 31. The plurality of positive electrode bodies 41 are arranged so that the centers in the positive electrode width direction are overlapped with each other when viewed from the positive electrode connecting direction. The positive electrode main body 41 other than the first positive electrode main body 41A arranged on the innermost circumference of the plurality of positive electrode main bodies 41 is formed smaller than the outer shape of the negative electrode main body 31 facing each other via the separator layers 36 and 46 in the electrode laminate 3. Has been done. For example, the outer shape of the seventh positive electrode body 41G is smaller than the outer shape of the eighth negative electrode body 31H and the sixth negative electrode body 31F facing each other via the separator layers 36 and 46. The outer shape of the eighth positive electrode body 41H is smaller than the outer shape of the seventh negative electrode body 31G facing each other via the positive electrode side separator layer 46.

As shown in FIGS. 3 and 4, the plurality of electrode connecting portions 42 are provided between a pair of positive electrode main bodies 41 adjacent to each other in the positive electrode connecting direction. Each electrode connecting portion 42 is formed so that the intermediate portion in the positive electrode connecting direction is the narrowest.

The positive electrode tab 45 extends from the eighth positive electrode main body 41H to the side opposite to the first positive electrode main body 41A. The positive electrode tab 45 extends in the positive electrode connecting direction with a width narrower than that of the plurality of electrode connecting portions 42.
In the positive electrode body 40 having the above configuration, the entire portion except the tip end side of the positive electrode tab 45 is covered with the positive electrode side separator layer 46 (see FIG. 3). That is, in addition to the front and back surfaces of the positive electrode body 41, the peripheral surface (side surface) and the front and back surfaces of the electrode connecting portion 42 and the side surface are covered with the positive electrode side separator layer 46.

As described above, the positive electrode side separator layer 46 is formed by curing the coating film. When the paint is applied to the front and back surfaces of the positive electrode body 40 shown in FIG. 4 except for the tip end side of the positive electrode tab, the paint can wrap around on the peripheral surface side (peripheral end surface side) of the positive electrode body 40. The negative electrode side separator layer 46 can be formed so as to cover almost the entire positive electrode body 40 except for the tip portion of the positive electrode tab 45.
For paint, after forming the coating film, if a paint that cures by heat is used, it is heated to the curing temperature, and if a paint that cures by irradiation with light such as ultraviolet rays is used, light of the wavelength required for curing is required. In the case of a paint that is irradiated with intensity and cured by drying, the paint can be cured by drying at an appropriate temperature. By curing the paint, a positive electrode body 40 having a structure covered with a separator layer 46 can be obtained as shown in FIG.

Next, the winding structure of the negative electrode body 30 and the positive electrode body 40 will be described.
When winding the negative electrode body 30 and the positive electrode body 40, first, the first negative electrode body 31A of the negative electrode body 30 and the first positive electrode body 41A of the positive electrode body 40 are overlapped with each other. At this time, the connection tabs 35 and 45 are arranged so as to face each other so that the negative electrode body 30 and the positive electrode body 40 are in a straight line with each other. From this state, the electrode laminate 3 shown in FIG. 2 can be formed by sequentially winding the negative electrode body 30 and the positive electrode body 40 in the same direction in a spiral shape.

For example, the first electrode connecting portion 32A may be first bent, the first positive electrode body 41A may be inserted between the first negative electrode body 31A and the second negative electrode body 31B, and the winding may be started. In this case, the first positive electrode body 41A is inserted between the first negative electrode body 31A and the second negative electrode body 31B so that the straight portion 43a of the first positive electrode body 41A abuts against the first electrode connecting portion 32A. be able to.
In any of the above-mentioned winding structures, the direction of the winding central axis is parallel to the first bottom wall portion 11 or the second bottom wall portion 21 when the battery 1 is drawn as shown in FIG. There is.

Further, the dimensions of each of the electrode connecting portions 32 in the negative electrode connecting direction increase as the distance from the first negative electrode main body 31A increases.
Here, attention is paid to a pair of negative electrode bodies 31 that are adjacent to each other in the expanded state, except for the eighth negative electrode body 31H among the plurality of negative electrode bodies 31. The distance between the pair of negative electrode bodies 31 in the wound state is such that the pair of negative electrode bodies 31 is paired with the negative electrode bodies 31 located on the outer peripheral side, the layers such as the negative electrode bodies 31 arranged between the pair of negative electrode bodies 31. As the number increases, it becomes larger. According to the present embodiment, the dimension of the electrode connecting portion 32 in the first direction increases as the distance from the first electrode connecting portion 32A increases, so that the distance between the pair of negative electrode main bodies 31 can be secured, and the winding of the pair of negative electrode main bodies 31 can be secured. It is possible to suppress the displacement of each other in the rotating state. Therefore, when viewed from the stacking direction, the positional deviation of the plurality of negative electrode bodies 31 is suppressed, and the negative electrode body 30 can be wound into a desired flat shape.

Moreover, the dimensions of each of the at least one electrode connecting portion 32 in the negative electrode connecting direction increase as the distance from the first electrode connecting portion 32A increases. According to this configuration, the negative electrode main body 31 on the outer peripheral side of the pair of negative electrode main bodies 31 is formed larger in the negative electrode connecting direction than the negative electrode main body 31 on the inner peripheral side. Therefore, in a state where the plurality of negative electrode bodies 31 overlap each other, the negative electrode body 31 on the outer peripheral side is provided with a non-overlapping region in which the negative electrode bodies 31 on the inner peripheral side do not overlap when viewed from the stacking direction.
By arranging the electrode connecting portion 32 connected to the negative electrode body 31 on the inner peripheral side and extending in the stacking direction in the non-superimposed region of the negative electrode body 31 on the outer peripheral side when viewed from the stacking direction, the electrode connecting portion is viewed from the stacking direction. It is possible to prevent the 32 from protruding from the negative electrode body 31 on the outer peripheral side. Therefore, the electrode laminate 3 can be wound into a desired flat shape without protrusions and arranged in the exterior body 3 at a high density.
As described above, the positional deviation of the plurality of negative electrode bodies 31 and the protrusion of the electrode connecting portions 32 are suppressed when viewed from the stacking direction. Therefore, it is possible to provide the battery (electrochemical cell) 1 in which the negative electrode body 30 can be wound into a desired flat shape, the degree of freedom in the shape is improved, and the capacity is secured.

When the strip-shaped negative electrode body 30 and the positive electrode body 40 shown in FIG. 4 are spirally wound to form the electrode laminate 3, the negative electrode body 30 or the positive electrode body 40 is wound using a film-shaped separator having the same plan view shape as the negative electrode body 30 or the positive electrode body 40. It is also possible to turn it. However, when the negative electrode body 30 and the positive electrode body 40 are wound together with the film-shaped separator, winding misalignment may occur in any of these. When either the negative electrode body 30 or the positive electrode body 40 and the separator are unwound, a portion where the electrode body protrudes to the outside of the separator is formed somewhere on the outer peripheral portion of the electrode laminate, which increases the risk of internal short circuit. ..
In this respect, if the negative electrode body 30 and the positive electrode body 40 having the separator layers 36 and 46 formed by curing the coating film have a wound structure, it is assumed that the negative electrode body 30 and the positive electrode body 40 are miswound. However, the separator layers 36 and 46 still cover the negative electrode body 30 and the positive electrode body 40. Therefore, as long as the negative electrode body 30 having the negative electrode side separator layer 36 and the positive electrode body 40 having the positive electrode side separator layer 46 are wound, there is no risk of internal short circuit. That is, if the electrode laminate 3 has a wound structure composed of a negative electrode body 30 and a positive electrode body 40 having separator layers 36 and 46 made of a cured coating film, a battery (electrochemical cell) in which the risk of internal short circuit does not occur. ) 1 can be provided.

Further, in the structure of the first embodiment, the exterior body 2 accommodating the electrode laminate 3 is composed of a laminate structure in which both sides of a metal foil such as an aluminum foil are covered with a resin layer, and the second peripheral wall portion 22 The bent portion 23 and the connecting wall 12b are press-molded while being bent and heat-sealed to form the sealing portion 5.
With this structure, if there is a defect in the resin layer located inside the second peripheral wall portion 22, the bent portion 23, and the connecting wall 12b, pinholes, cracks, streaks, etc. are formed in the resin layer due to press working. May cause defective parts.

If these defective portions are generated, the electrolytic solution filled in the accommodating portion 4 may come into contact with the aluminum foil in the exterior body 2. Here, for example, there is a portion where a part of the negative electrode body 30 is exposed on the outer peripheral portion of the electrode laminate 3, and the negative electrode potential is applied to the aluminum foil when this portion is close to or in contact with the aluminum foil in the exterior body 2. In that case, the negative electrode deterioration of the aluminum foil due to the contact between the metallic lithium and the aluminum may progress. However, in the case of the electrode laminate 3 of the first embodiment, since the separator layers 36 and 46 surely cover the negative electrode body 30 and the positive electrode body 40, a defective portion is generated on the inner surface side of the exterior body 2 and the aluminum foil is formed. Even if it is exposed, the deterioration of the aluminum foil does not proceed. Further, since the separator layers 36 and 46 surely cover the negative electrode body 30 and the positive electrode body 40, the battery (electrochemical cell) 1 with reduced risk of internal short circuit can be provided.

In the present embodiment, when the negative electrode body 30 and the positive electrode body 40 are wound around the electrode laminated body 3, the negative electrode body 30 and the positive electrode body 40 provided with the separator layers 36 and 46 after the paint is cured are used. I wound it.
On the other hand, the coating film applied to form the separator layers 36 and 46 is not completely cured, but the negative electrode body 30 and the positive electrode body 40 are wound around the electrode laminate 3 at the stage of being in a semi-cured state. After that, the separator layers 36 and 46 may be completely cured under the required curing conditions.

When the negative electrode body 30 and the positive electrode body 40 having the separator layers 36 and 46 in the semi-cured state are wound, the semi-cured paint existing around the negative electrode body 30 and the half existing around the positive electrode body 40 at the time of winding are wound. The contact portions of the cured paint can be brought into close contact with each other to form an integrated state in which they are fused with each other.
When heat treatment or the like is performed under the condition that the separator layers 36 and 46 are completely cured from this fused and integrated state, the separator layer 36 of the negative electrode body 30 and the separator layer 46 of the positive electrode body 40 are fused and integrated. The electrode laminate 3 cured as it is can be obtained.
With the electrode laminate 3 having this structure, it is possible to obtain the electrode laminate 3 having a structure in which the negative electrode body 30 and the positive electrode body 40 are more completely covered with the separator layers 36 and 46.

When the exterior body 2 shown in FIG. 1 is configured, as an example, the bent portion 23 is formed in the first container 10 before the bent portion 23 is formed on the upper side of the first peripheral wall portion 12 by press working. It is a ring plate-shaped flange. Further, in the state before forming the second peripheral wall portion 22 and the bent portion 23 by press working on the outer peripheral side of the second bottom wall portion 21 in the second container 20, these are set as ring plate-shaped flange portions.
The above-mentioned electrode laminate 3 is housed inside the second container 20 together with the electrolytic solution, and after the flange portion of the first container 10 is placed on the flange portion of the second container, a ring shape is formed with respect to the two flange portions. The structure shown in FIG. 1 can be obtained by processing the second peripheral wall portion 22, the bent portion 23, and the connecting wall 12b into the shape shown in FIG. 1 by press working with a punch having a protrusion. Details of the technique for pressing the flange portion are described in JP-A-2018-852214 (Patent No. 6284248).

When the first container 10 and the second container 20 are composed of the above-mentioned laminated structure, the shape of the exterior body 2 is fixed in a state where the flange portion is pressed to form the first container 10 and the second container 20. When the electrode laminate 3 enclosed inside is in a slightly inflated state instead of in a state of being slightly inflated, the exterior body 2 is also in a slightly inflated state accordingly.
In order to avoid this state, the coating films constituting the separator layers 36 and 46 are heated to a temperature at which the coating films constituting the separator layers 36 and 46 are completely cured during the above-mentioned press working or in a state where a separate pressing for molding is performed after the press working. Perform heat treatment to hold for a predetermined time. By this heat treatment, the coating films constituting the separator layers 36 and 46 can be completely cured, so that the well-shaped battery 1 shown in FIG. 1 can be obtained.

By completely curing the coating film in the semi-cured state from the state in which the shape of the exterior body 2 is adjusted, the overall shape is in a well-formed state, and the electrode laminate 3 covered entirely with the separator layers 36 and 46 is provided. Battery 1 can be obtained.
In particular, when the exterior body 2 is a laminated structure of a metal foil and a resin layer, the exterior body 2 is flexible in a state where the electrode laminate 3 is housed, and the presence of a coating film in a semi-cured state is also present. Although the overall shape is not solidified, the overall shape of the battery 1 can be formed into a well-shaped and strong shape by adjusting the shape of the exterior body 2 and completely curing the coating film.

Further, if the separator layer is formed by integrating the coating film curing layer that individually covers the peripheral surface of the negative electrode body 30 and the peripheral surface of the positive electrode body 40, the negative electrode body 30 is wound when the negative electrode body 30 and the positive electrode body 40 are wound. Even if a part of the positive electrode body 40 is disturbed, the negative electrode body 30 and the positive electrode body 40 are surely covered with the separator layer. Further, the outer peripheral surface of the electrode laminate 3 around which the negative electrode body 30 and the positive electrode body 40 are wound can be reliably covered with the separator layer. As a result, it is possible to provide an electrochemical cell that does not cause an internal short circuit.

"Second embodiment"
FIG. 5 shows a cross-sectional structure of the battery 50 of the second embodiment in which the electrochemical cell according to the present invention is applied to a secondary battery, and the battery 50 is a button-shaped battery having a circular shape in a plan view. The battery 50 of the second embodiment includes a container-shaped exterior body 2 and an electrode laminate 53 housed inside the exterior body 2.
The exterior body 2 used in the second embodiment has the same configuration as the exterior body 2 used in the first embodiment. Therefore, regarding the configuration of the exterior body 2, the same reference numerals are given to the configurations equivalent to those of the first embodiment, and detailed description of the same configuration will be omitted.
In the exterior body 2 of the second embodiment, the first container 10 and the second container 20 are made of a laminated structure, have an accommodating portion 4, and the first container 10 and the second container 20 are joined at the sealing portion 5. The structures are equivalent. Further, the structure in which the second peripheral wall portion 22, the bent portion 23, and the connecting wall 12b are formed at the joint portion 5 and the bent portion 23 and the connecting wall 12b are heat-sealed by press working is also the same.

In the battery 50 of the second embodiment, the structure of the electrode laminate 53 is different from that of the electrode laminate 3 of the first embodiment.
In the second embodiment, the electrode laminate 53 has a negative electrode body 55 shown in FIG. 6 (A) formed of a coating film cured layer and a negative electrode side separator layer 56 shown in FIG. 6 (B), and FIG. 6 (C). ) Is formed with the positive electrode side separator layer 58 shown in FIG. 6 (D) and wound in a spiral shape.
The negative electrode body 55 has a different plan view shape from the negative electrode body 30 used in the first embodiment, but has the same laminated structure, and the positive electrode body 57 is flat with the positive electrode body 40 used in the first embodiment. The visual shape is different, but the laminated structure is the same.

The negative electrode body 55 includes a negative electrode active material layer in which a negative electrode active material is applied to one side or the front and back surfaces of a band-shaped negative electrode current collector made of a metal foil such as copper. The positive electrode body 57 includes a positive electrode active material layer in which a positive electrode active material is applied to one side or the front and back surfaces of a band-shaped positive electrode current collector made of a metal foil such as aluminum. As the metal material constituting the negative electrode current collector and the positive electrode current collector and the material constituting the positive electrode active material layer and the negative electrode active material layer, those described in the first embodiment can be used.
In order to form the negative electrode active material layers on both sides of the strip-shaped negative electrode current collector and to form the separator layer 56 covering them, it is equivalent to the one used for forming the separator layers 36 and 46 in the first embodiment. Paint can be used.
When the paint is applied so as to cover the negative electrode current collector and the negative electrode active material layer, an uncoated portion is provided on one end side in the length direction of the negative electrode current collector to expose the end portion of the negative electrode current collector. This exposed portion can be a connection tab 55a. When the paint is applied so as to cover the positive electrode current collector and the positive electrode active material layer, an uncoated portion is provided on one end side in the length direction of the positive electrode current collector to expose the end portion of the positive electrode current collector. This exposed portion can be a connection tab 57a.

After applying the paint for forming the separator layer, heat treatment or the like is performed so as to satisfy the curing condition or the semi-curing condition of the coating film as described in the first embodiment to form the negative electrode body 56 and the positive electrode body 57, and these are formed. The electrode laminate 59 shown in FIG. 6 (F) can be obtained by winding it in an annular shape.
When the laminate 59 is obtained, it is stored together with the electrolytic solution in the accommodating portion 4 composed of the first container 10 and the second container 20 before fusion by press working, and the second peripheral wall portion 22 is bent by press working. The battery 50 having the structure shown in FIG. 5 can be obtained by forming the portion 23 and the connecting wall 12b and heat-sealing the resin layer on the outer surface side of the bent portion 23 and the resin layer on the inner peripheral side of the connecting wall 12b. it can.

The battery 50 shown in FIG. 5 also has a wound structure of the negative electrode body 55 and the positive electrode body 57 provided with the separator layers 56 and 58 having the cured coating film, as in the battery 1 of the first embodiment. For example, even if the negative electrode body 55 and the positive electrode body 57 are miswound, the separator layers 56 and 58 still cover the negative electrode body 55 and the positive electrode body 57. Therefore, as long as the negative electrode body 55 having the negative electrode side separator layer 56 and the positive electrode body 57 having the positive electrode side separator layer 58 are wound, there is no risk of internal short circuit. That is, if the electrode laminate 59 has a wound structure composed of a negative electrode body 55 and a positive electrode body 57 having separator layers 56 and 58 made of a cured coating film, a battery (electrochemical cell) in which an internal short-circuit risk does not occur. 50 can be provided.

Further, in the battery 50 shown in FIG. 5, an electrode laminate 53 having a semi-cured coating film is housed in the exterior body 2, and heat treatment is performed after fusion by press working to completely cure the separator layers 56 and 58. You may let me. In this case, the same effect as when the semi-cured coating film is used in the first embodiment shown above can be obtained.
In the second embodiment described above, in any of the above-described winding structures, the direction of the winding central axis of the negative electrode body 55 and the positive electrode body 57 is the first bottom when the battery 50 is drawn as shown in FIG. The orientation is perpendicular to the wall portion 11 or the second bottom wall portion 21.

"Third embodiment"
7 and 8 show a cross-sectional structure of the battery 60 of the third embodiment in which the electrochemical cell according to the present invention is applied to a secondary battery, and the battery 60 is a circular button type battery. The battery 60 of the third embodiment includes a flat container-shaped exterior body 62 and an electrode laminate 63 housed inside the exterior body 62 together with an electrolytic solution (not shown). As the electrolytic solution, an electrolytic solution in which a supporting salt is dissolved in a non-aqueous solvent is preferably used.

The exterior body 62 has a circular shape in a plan view. Specifically, the exterior body 62 is assembled to the bottomed tubular positive electrode side container 65 via a gasket 66, and forms a storage space S between the positive electrode side container 65 and the positive electrode side container 65. It has a tubular negative electrode side container 67.
In the third embodiment shown in FIGS. 7 and 8, the central axes of the positive electrode side container 65 and the negative electrode side container 67 are arranged on a common axis. Hereinafter, this common axis is referred to as the axis O, the negative electrode side container 67 side along the axis O direction is referred to as the upper side, the positive electrode side container 65 side is referred to as the lower side, and is orthogonal to the axis O in a plan view from the axis O direction. The direction of rotation is referred to as the radial direction, and the direction of orbiting around the axis O is referred to as the circumferential direction.

The positive electrode side container 65 and the negative electrode side container 67 are formed by drawing, for example, a metal plate material such as a stainless steel plate. In the illustrated example, the inner diameter of the positive electrode side container 65 is larger than the outer diameter of the negative electrode side container 67.
The gasket 66 has an annular shape arranged coaxially with the axis O, and is fitted in the peripheral wall portion 65a of the positive electrode side container 65. The gasket 66 is formed with a groove portion 69 that holds the peripheral wall portion 67a of the negative electrode side container 67 over the entire circumference. The negative electrode side container 67 is fixed to the positive electrode side container 65 by caulking the upper end side of the peripheral wall portion 65a of the positive electrode side container 65 inward in the radial direction while the peripheral wall portion 67a is held in the groove portion 69 of the gasket 66. To.
The gasket 66 is formed of an insulating material such as a resin material (for example, polypropylene (PP), polyphenylene sulfide (PPS), polyetheretherketone (PEEK)).

The electrode laminated body 63 has a structure in which a plurality of disc-shaped negative electrode bodies 70 and positive electrode bodies 71 described below are laminated.
The negative electrode body 70 has a disc-shaped negative electrode current collector 72 and a negative electrode active material layer 73 coated on the upper surface thereof, and the negative electrode active material layer 73 is covered with a negative electrode side separator layer 75 made of a coated cured layer. There is.
The positive electrode body 71 has a disk-shaped positive electrode current collector 76 and a positive electrode active material layer 77 coated on the upper surface thereof, and the positive electrode active material layer 77 is covered with a positive electrode side separator layer 78 made of a coated cured layer. There is.

The negative electrode current collector 72 is made of a material equivalent to the material constituting the negative electrode current collector of the negative electrode body 30 in the battery 1 of the first embodiment, for example, copper foil, and the positive electrode current collector 72 is the battery 1 of the first embodiment. It is made of a material equivalent to the material constituting the positive electrode current collector of the positive electrode body 40, for example, an aluminum foil.
The negative electrode active material layer 73 is made of the same material as the material constituting the negative electrode active material layer of the negative electrode body 30 in the battery 1 of the first embodiment, and the positive electrode active material layer 77 is made of the positive electrode body 40 in the battery 1 of the first embodiment. It is made of the same material as the material constituting the positive electrode active material layer.

The material constituting the negative electrode side separator layer 75 and the positive electrode side separator layer 78 is made of the same material as the material forming the negative electrode side separator layer 50 and the positive electrode side separator layer 60 in the battery 1 of the first embodiment.
The electrode laminate 63 of the third embodiment has a structure in which a plurality of negative electrode bodies 70 having a structure in which the negative electrode active material layer 73 is covered with a negative electrode side separator layer 75 and a structure in which the positive electrode active material layer 77 is covered with a positive electrode side separator layer 78. A plurality of positive electrode bodies 71 are alternately laminated in the thickness direction thereof.
In the electrode laminate 63, the outer peripheral portion of the negative electrode current collector 72 is arranged on the outer peripheral portion of each negative electrode body 70, and the outer peripheral portion of the positive electrode current collector 76 is arranged on the outer peripheral portion of each positive electrode body 71. The outer diameter of the positive electrode active material layer 77 is formed to be smaller than the outer diameter of the negative electrode active material layer 73.

Although the description is omitted in FIGS. 7 and 8, a connecting conductor inside the exterior body 62 is connected to all the negative electrode current collectors 72 provided in the electrode laminate 63 and conducted to the negative electrode side container 67. Is provided, and a connecting conductor that is connected to all the positive electrode current collectors 76 provided in the electrode laminate 63 and conducts to the positive electrode side container 63 is provided.

The battery 60 described above has a structure in which the negative electrode active material layer 73 is covered with the negative electrode side separator layer 75, and the positive electrode active material layer 77 is covered with the positive electrode side separator layer 78. Therefore, it is possible to provide a structure in which the negative electrode side separator layer 75 and the positive electrode side separator layer 78 are sufficiently insulated and separated.
By using the coating film curing type negative electrode side separator layer 75 and positive electrode side separator layer 78, the separator layers 75 and 78 can be arranged at necessary positions, and a structure in which the risk of internal short circuit is unlikely to occur can be provided.

1 ... Battery (electrochemical cell), 2 ... Exterior body, 3 ... Electrode laminate, 4 ... Storage part, 5 ... Sealing part, 10 ... First container (outer container), 11 ... First bottom wall part, 12 ... 1st peripheral wall part, 12b ... connection wall, 15 ... negative electrode plate, 20 ... second container (inner container), 21 ... second bottom wall part, 22 ... second peripheral wall part, 23 ... bent part, 30 ... negative electrode Body, 31 ... Electrode body, 32 ... Electrode connection, 35 ... Connection tab, 36 ... Negative electrode side separator layer, 40 ... Positive electrode body, 41 ... Electrode body, 42 ... Electrode connection, 45 ... Connection tab, 46 ... Positive electrode side Separator layer, 50 ... Battery (electrochemical cell), 55 ... Negative electrode body, 56 ... Negative electrode side separator layer, 57 ... Positive electrode body, 58 ... Positive electrode side separator layer, 59 ... Electrode laminate, 60 ... Battery (electrochemical cell) , 62 ... exterior body, 63 ... electrode laminate, 65 ... positive electrode side container, 66 ... gasket, 67 ... negative electrode side container, 70 ... negative electrode body, 71 ... positive electrode body, 72 ... negative electrode current collector, 73 ... negative electrode active material Layers, 75 ... Negative electrode side separator layer, 76 ... Positive electrode current collector, 77 ... Positive electrode active material layer, 78 ... Positive electrode side separator layer.

Claims (9)

The positive electrode body and the negative electrode body are wound around an arbitrary winding central axis via a separator layer composed of a coating film curing layer covering at least one surface of at least one of the band-shaped positive electrode body and the band-shaped negative electrode body. Equipped with a rotating electrode laminate
The electrode laminate is housed in an outer body composed of an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, and the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and bent and fused and integrated. An electrochemical cell characterized by that. The positive electrode body and the negative electrode body are wound around an arbitrary winding central axis via a separator layer composed of a coating film curing layer covering at least one surface of at least one of the band-shaped positive electrode body and the band-shaped negative electrode body. Equipped with a rotating electrode laminate
An electrochemical cell characterized in that the electrode laminate is housed in an exterior body in which a positive electrode can and a negative electrode can are integrated via a gasket. A claim characterized in that a separator layer is provided in which a coating film cured layer provided on both front and back surfaces of the band-shaped positive electrode body and the peripheral surface including the side surfaces of the band-shaped negative electrode body is fused and integrated in the wound state. The electrochemical cell according to claim 1 or 2. An extension portion is formed on the positive electrode body and a part of the negative electrode body, and a connection tab is formed on the tip end side of the extension portion without a separator layer made of the coating film cured layer. The electrochemical cell according to any one of claims 1 to 3. The electricity according to any one of claims 1 to 4, wherein the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are made of a laminated structure in which resin layers are provided on both sides of a metal foil. Chemical cell. Both the band-shaped positive electrode body and the band-shaped negative electrode body have a plurality of electrode bodies having a plan view shape similar to the plan view shape of the exterior body, and an electrode connecting portion for connecting the plurality of electrode bodies. , The positive electrode body and the negative electrode body are spirally wound around each other via the coating film cured layer and integrated.
The claim is characterized in that the electrode body and the electrode connecting portion of the positive electrode body, and the electrode body and the electrode connecting portion of the negative electrode body are all covered with a separator layer made of the coating film cured layer. The electrochemical cell according to any one of 1 to 5. The invention according to any one of claims 1 to 6, wherein both the electrode body and the electrode connecting portion are provided with active material layers on both the front and back surfaces of a current collector layer made of a metal foil. Electrochemical cell. An electrode laminate formed by laminating the positive electrode body and the negative electrode body is provided via a separator layer composed of a coating film curing layer covering at least one surface of at least one of the positive electrode body and the negative electrode body.
The electrode laminate is housed in an outer body composed of an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, and the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and bent and fused and integrated. An electrochemical cell characterized by that. In the method for producing an electrochemical cell according to any one of claims 1 and 3 to 7, a curable coating film is applied to at least one surface of at least one of a band-shaped positive electrode body and a band-shaped negative electrode body. After the formation, the positive electrode body and the negative electrode body are wound around the positive electrode body and the negative electrode body in a semi-cured state to form an electrode laminate, and the electrode laminate is housed inside the exterior body to shape the exterior body. After that, a method for producing an electrochemical cell, which comprises curing the semi-cured coating film.

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