JP7288816B2 - Electrochemical cell and manufacturing method thereof - Google Patents

Description

The present invention relates to an electrochemical cell and its method of manufacture.

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

For example, as a porous separator for batteries, the following Patent Document 1 discloses a process of printing a thin layer of a separator precursor on an electrode and vulcanizing the thin layer to transform it into a microporous composite separator structure. is disclosed.
Patent Document 2 below describes a polymer solid electrolyte obtained by impregnating expanded porous PTFE (polytetrafluoroethylene) with a polymer solid electrolyte resin solution and then removing the solvent, and voids in the expanded porous PTFE. There is described a composite polymer solid electrolyte membrane/electrode integrally formed body in which an electrode catalyst and an electrode filled with an electrode component containing a polymer solid electrolyte are integrally formed.
Further, as described in Patent Document 3 below, an electrode is formed by winding a strip-shaped positive electrode and a negative electrode with a sheet-shaped separator interposed, and this electrode is placed inside an exterior body consisting of a positive electrode-side container and a negative electrode-side container. Contained button electrochemical cells are known.

JP-A-10-334877 JP-A-08-329962 JP 2016-100122 A

In the configuration described in Patent Document 3, the exterior body that accommodates the electrodes in which the strip-shaped positive electrode and negative electrode are wound is a positive electrode-side container and a negative electrode-side container having a laminate structure in which resin layers are laminated on both sides of a metal foil such as aluminum. A different exterior body is used. Also, the junction between the positive electrode side container and the negative electrode side container is formed by pressing the outer peripheral wall of the inner container and the outer peripheral wall of the outer container to overlap each other while bending them.

However, when the outer wall of a container with a laminate structure is bent by pressing, the resin layer is stretched together with the metal foil. part may occur.
If these defects occur on the outer peripheral wall of the inner container, the electrolytic solution enclosed in the container may come into contact with the metal foil. If the aforementioned electrochemical cell is a lithium-ion battery and the metal foil is aluminum, aluminum may alloy with lithium at the negative electrode potential, and the negative electrode potential may accelerate the deterioration of aluminum. rice field.

In a container having a laminate structure, the outer resin layer is tough and resin such as nylon having a high melting point is applied. However, nylon is highly hydrophilic and has a property of swelling when it contains moisture. If the outer resin layer loses volume due to swelling and cracks occur, there is a risk that the sealing portion will deteriorate.
In particular, in the case of a coin-type electrochemical cell, since the internal volume is small, the space between the current collector foil constituting the electrode and the outer peripheral wall of the container is narrow, and structurally, there is a problem that an internal short circuit is likely to occur. For example, when electrodes are formed by winding strip-shaped positive and negative electrodes with a sheet-shaped separator interposed therebetween, even the slightest winding misalignment may cause the electrode to protrude outside the separator and cause an internal short circuit.

The present invention has been made in view of the conventional circumstances as described above. An object of the present invention is to provide an electrochemical cell capable of improving yield and a method of manufacturing the same.

(1) In the present invention, at least one of a strip-shaped positive electrode body and a strip-shaped negative electrode body is wound at an arbitrary winding center through a separator layer composed of a coating film cured layer covering at least one surface of the positive electrode body and the negative electrode body. Equipped with an electrode laminate wound around an axis, comprising an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, wherein the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and folded. The electrode laminate is accommodated in a fused and integrated outer package, and the separator layer is a coating film hardening layer provided on the peripheral surface including the front and back surfaces and the side surfaces of the strip-shaped positive electrode body and the strip-shaped negative electrode body. The separator layer is fused and integrated in the wound state .

(2) In the present invention, at least one of the strip-shaped positive electrode body and the strip-shaped negative electrode body is wound at an arbitrary winding center through a separator layer composed of a coating film cured layer covering at least one surface. The electrode laminate is provided with an electrode laminate wound around an axis, 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, and the separator layer is the strip-shaped positive electrode. and a cured coating layer provided on the peripheral surface including both front and back surfaces and side surfaces of the strip-shaped negative electrode body are fused and integrated in the wound state.

In the case of an electrode laminate having a structure in which a positive electrode body and a negative electrode body are wound and provided with a separator layer composed of a cured coating layer, 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 little risk of short circuit even if the winding is dislocated in the body.
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, if the positive electrode body or the negative electrode body is wound out of alignment, a part of the electrode body protrudes from the separator layer, which causes an internal short circuit. May pose a risk. Simply enlarging the separator to avoid the risk of an internal short circuit lowers 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 cured coating layer are wound can provide an electrochemical cell that does not cause a decrease in battery capacity density per volume.

If the separator layer is formed by integrating the coating film cured layer that separately covers the peripheral surface of the positive electrode body and the peripheral surface of the negative electrode body, when the positive electrode body and the negative electrode body are wound, part of the positive electrode body and the negative electrode body The positive electrode body and the negative electrode body are reliably covered with the separator layer even if the winding is disturbed. Moreover, the outer peripheral surface of the electrode laminate obtained by winding the positive electrode body and the negative electrode body is 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.

( 3 ) In the electrochemical cell according to an aspect of the present invention, an extension is formed in a part of the positive electrode body and the negative electrode body, and the tip end side of the positive electrode side extension part and the negative electrode side extension part are formed. It is preferable that a connection tab not formed with the separator layer composed of the coating film cured layer is formed on the leading end side of the portion.

By connecting the connection tab on the positive electrode side to the positive terminal on one container side and connecting the connection tab on the negative electrode side to the negative terminal on the other container side, the terminal on the container side can be connected without using a separate tab for conduction. can be connected to the positive and negative bodies. Therefore, the conductive tab can be omitted, and the electrodes can be arranged in the space where the conductive tab was provided, so that an electrochemical cell with a high battery capacity density per volume can be provided.

( 4 ) In the electrochemical cell according to one aspect 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 laminate structure in which a resin layer is provided on both sides of a metal foil.
(5) In the electrochemical cell according to one aspect of the present invention, an extension is formed on a part of the positive electrode body and the negative electrode body, and a separator layer composed of the cured coating layer is formed on a tip end side of the extension. It is preferable that the connecting tabs are formed without forming, and the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are composed of a laminate structure in which a resin layer is provided on both sides of a metal foil.

If the exterior body is composed of a laminated structure containing a metal foil, the metal foil portion can prevent the intrusion of moisture, and an electrochemical cell can be provided without the risk of moisture intrusion from the outside into the interior side of the exterior body. .
In addition, even if defects such as pinholes, tears, and streaks occur in the resin layer, the metal foil of the exterior body comes into contact with the electrolytic solution, and further, even if there is a risk of contact with the electrode laminate side. Since the separator layer composed of the cured layer of the coating film can be surely interposed between the metal foil and the metal foil, there is no fear of applying an electric potential to the metal foil, and a structure in which deterioration of the metal foil is unlikely to occur can be provided.

(6) In the electrochemical cell according to one aspect of the present invention, each of the strip-shaped positive electrode body and the strip-shaped negative electrode body includes a plurality of electrode bodies each having a plan view shape similar to the plan view shape of the exterior body. and an electrode connection portion for connecting the plurality of electrode bodies, wherein the positive electrode body and the negative electrode body are spirally wound and integrated with each other through the coating film cured layer, and the electrode body of the positive electrode body is integrated. and the electrode connecting portion, and the electrode main body and the electrode connecting portion of the negative electrode body are preferably 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 outer package, 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 negative electrode body An electrochemical cell equipped with an electrode laminate having a shape suitable for the outer shape of the outer package, which can be accommodated in the outer package at high density without gaps, by overlapping the electrode bodies on the negative electrode side and winding them in a spiral shape. can provide. By covering both the electrode main body and the electrode connecting portion with the separator layer, the entire electrode stack is covered with the separator layer, and an electrochemical cell with little short circuit risk can be provided.

(7) In the electrochemical cell according to one aspect of the present invention, it is preferable that both the electrode main body and the electrode connecting portion include active material layers on both front and back surfaces of current collector layers made of 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 front and back surfaces of a current collector layer made of metal foil can be applied. If the separator layer consists of a coated and cured layer, it is possible to reliably cover the entirety of the positive electrode body and the negative electrode body even in a laminated structure of a current collector layer and an active material layer provided thereon. Therefore, for example, even if the positive electrode body and the negative electrode body are misaligned during winding, it is possible to provide an electrochemical cell having a structure in which the positive electrode body and the negative electrode body are reliably covered with the separator layer.

(8) In the electrochemical cell according to one aspect of the present invention, at least one of the positive electrode body and the negative electrode body is separated from the positive electrode body and the negative electrode body via a separator layer composed of a cured coating layer covering at least one surface of the positive electrode body and the negative electrode body. An exterior comprising an electrode laminate formed by lamination and comprising an inner container having an outer peripheral wall and an outer container having an outer peripheral wall, wherein the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and folded and fused together. The electrode laminate is housed in a body.

If it is an exterior body in which the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are overlapped and fused while being folded, the joint where the inner container and the outer container are fused has good adhesion and sealing performance. It can provide an excellent exterior body.

(9) A method for manufacturing an electrochemical cell according to one aspect of the present invention is the method for manufacturing an electrochemical cell according to any one of (1) and (3) to (7), wherein a strip-shaped positive electrode body and a strip-shaped 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 while the coating film is semi-cured to form an electrode laminate, and this electrode The semi-cured coating film is cured after the laminate is accommodated in the exterior body and the shape of the exterior body is adjusted.

By forming an electrode laminate by winding a positive electrode body and a negative electrode body having a semi-cured coating film on their peripheral surfaces, 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 come into contact with each other. It can be wound while being integrated with each other. The electrode laminate having the semi-cured coating film adhered in this manner is accommodated inside the exterior body, and the semi-cured coating film is completely cured from the state in which the exterior body is adjusted in shape. It is possible to obtain an electrochemical cell in a well-formed state and having 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 the state in which the electrode laminate is accommodated, and together with the existence of the semi-cured coating film, the electrochemical Although the overall shape of the cell is not solidified, an electrochemical cell with a well-shaped and strong structure can be provided by completely curing the coating film after shaping the exterior body.

According to the present invention, if it is an electrode laminate having a structure in which a positive electrode body and a negative electrode body are wound and provided with a separator layer composed of a cured coating layer, the positive electrode and the negative electrode can be reliably insulated and separated by the separator layer. Thus, it is possible to provide an electrochemical cell in which the risk of short-circuiting is small even if winding misalignment occurs in the negative electrode body.

BRIEF DESCRIPTION OF THE DRAWINGS It is the perspective view which made the cross section a part of secondary battery (electrochemical cell) of 1st Embodiment which concerns on this invention. FIG. 2 is a perspective view showing an electrode laminate obtained by winding a positive electrode body and a negative electrode body with a separator layer; FIG. 4 is a plan view showing the unfolded state of the positive electrode body and the negative electrode body that constitute the same electrode laminate. 4 is a plan view showing a state in which a separator layer is removed from the positive electrode body and the negative electrode body shown in FIG. 3; FIG. FIG. 2 is a perspective view of a partial cross-section of a secondary battery (electrochemical cell) according to a second embodiment of the present invention; It shows an electrode laminate housed in the secondary battery of the second embodiment, (A) is a front view showing an example of a negative electrode-side current collector layer, (B) is a separator layer on the current collector layer. (C) is a front view showing an example of the positive electrode side current collector layer, (D) is a plan view showing the state where the current collector layer is coated with a separator layer, (E) 1] is a perspective view showing an electrode laminate. [FIG. FIG. 3 is a cross-sectional view of a secondary battery (electrochemical cell) according to a third embodiment of the invention; It is the perspective view which made the cross section a part of secondary battery of the said 3rd Embodiment.

An embodiment of an electrode according to the present invention will be described below with reference to the drawings. In the following embodiments, as an example of an electrochemical cell, a coin-type lithium ion secondary battery (hereinafter simply referred to as "battery") will be cited, and electrodes mounted in this battery will be described.
In addition, in the drawings used for the following description, the scale of each member is appropriately changed so that each member has a recognizable size.

<First Embodiment>
FIG. 1 is a partial cross-sectional view showing a first embodiment in which an electrochemical cell according to the present invention is applied to a secondary battery.
The battery 1 of the present embodiment is a button-shaped battery that is circular in plan view. This battery 1 includes a container-shaped exterior body 2 and an electrode laminate 3 housed inside the exterior body 2 . Although not shown in FIG. 1, the interior of the exterior body 2 is filled with an electrolytic solution. As this electrolytic solution, an electrolytic solution obtained by dissolving a supporting salt in a non-aqueous solvent is preferably used.

(Exterior body)
The exterior body 2 includes an accommodating portion 4 that accommodates the electrode laminate 3 and a sealing portion 5 that is bent along the outer periphery 4 a of the accommodating portion 4 . The sealing portion 5 is formed by being bent along the outer periphery 4a of the accommodating portion 4 by drawing, for example.
The exterior body 2 includes a first container (outer container) 10 and a second container (inner container) 20 that sandwich the electrode laminate 3 therebetween. The first container 10 and the second container 20 are each formed of a laminate structure (laminate film). The laminate structure consists of a metal foil (metal layer), a bonding layer (resin layer) provided on the overlapping surface (inner surface) and covering the metal foil, and a protective layer (resin layer) provided on the outer surface and covering the metal foil ( resin layer). The metal layer is made of, for example, aluminum, stainless steel, or the like, and is formed of a metal foil that blocks outside air and water vapor. The fusing layer on the overlapping surface is formed of, for example, a single substance or a copolymer of a thermoplastic resin such as polyolefin such as polyethylene or polypropylene. The protective layer on the outer surface is formed of, for example, the above-described 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 cylindrically extending from the outer circumference of the first bottom wall portion 11 . A first through hole 13 is formed in the center of the first bottom wall portion 11 .
A negative electrode plate 15 formed by integrating a copper plate or a copper plate with a nickel plate or the like is heat-sealed to the inner surface of the first bottom wall portion 11 via a first sealant ring 14 . The first sealant ring 14 is formed by molding a sealant film into a ring shape 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 of the electrode laminate 3, which will be described later. 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 plate 15 is exposed to the outside through the first through hole 13 and functions as a negative terminal of the battery 1 . Also, if the negative plate 15 is made of nickel or a nickel alloy, the nickel plate may be omitted.

The second container 20 includes a circular second bottom wall portion 21 , a second peripheral wall portion 22 cylindrically extending from the outer peripheral edge of the second bottom wall portion 21 , and a second peripheral wall portion extending from the opening edge of the second peripheral wall portion 22 . A bent portion 23 is provided which 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 side.
The second bottom wall portion 21 is arranged on the side opposite to the first bottom wall portion 11 of the first container 10 with the electrode laminate 3 interposed therebetween. The second bottom wall portion 21 is formed to have the same outer diameter as 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 increased at the end portion on the second peripheral wall portion 12 side through the stepped portion 12a. An enlarged connecting peripheral wall 12 b is formed and joined to the outside of the second peripheral wall portion 22 .
In addition, when the outer diameter of the first peripheral wall portion 12 is formed to be the same as the outer diameter of the connection peripheral wall 12b, the stepped portion 12a and the connection peripheral wall 12b are omitted, and the opening side of the first peripheral wall portion 12 is directly connected to the second peripheral wall. It may be extrapolated to the portion 22 .

A positive electrode plate 26 made of aluminum or the like is heat-sealed to the inner surface of the second bottom wall portion 21 via a second sealant ring 25 . The second sealant ring 25 is made of 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 of the electrode laminate 2, which will be described later. A low contact resistance plate such as a nickel plate is preferably welded to the center of the outer surface of the positive electrode plate 26 . The nickel plate in this case is exposed to the outside through the second through hole 24 and functions as the positive electrode terminal of the battery 1 . Note that, for example, a positive electrode plate made of stainless steel or the like can be used instead of the positive electrode plate 26 made of aluminum.

The second peripheral wall portion 22 extends cylindrically 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 periphery 4 a of the housing portion 4 . The bent portion 23 is bent from the end portion of the second peripheral wall portion 22 on the first bottom wall portion 11 side along the second peripheral wall portion 22 toward the second bottom wall portion 21 side to form a cylindrical shape. there is The bent portion 23 is spaced outward from the second peripheral wall portion 22 .
The second peripheral wall portion 22 is arranged inside the connection wall 12 b of the first peripheral wall portion 12 and inside the bent portion 23 . Further, the bent portion 23 is arranged inside the connection wall 12b of the first peripheral wall portion 12, and the fusion layer of the bent portion 23 and the fusion layer of the connection 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 connection wall 12b by ultrasonic wave or heating. Therefore, the outer periphery of the housing portion 4 is sealed with the sealing portion 5 . With the structure described above, the first container 10 and the second container 20 are superimposed and joined to form the exterior body 2 . The sealing portion 5 is formed in a cylindrical shape on the outside of the housing portion 4 and is bent along the outer circumference 4 a of the housing portion 4 .
A sealed space is formed in the housing portion 4 by stacking the first container 10 and the second container 20 . Specifically, the housing portion 4 is defined by a first bottom wall portion 11, a second bottom wall portion 21, and a second peripheral wall portion 22, and is formed in a circular shape in plan view.

(Electrode laminate)
FIG. 2 is a perspective view showing the electrode laminate 3 of the first embodiment. This electrode laminate 3 includes, as shown in FIG. It consists of a cathode body 40 coated with 46 .
The electrode laminate 3 is an electrode laminate in which the negative electrode body 30 and the positive electrode body 40 are alternately stacked and folded. Specifically, the electrode laminate 3 is formed by stacking the negative electrode body 30 and the positive electrode body 40 with the separator layers 36 and 46 interposed therebetween as shown in FIG. 2 and winding them in a flat shape. 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 excluding the tip portions of the connection tabs 35 to be described later. The positive electrode-side separator layer 46 is formed so as to cover the entire negative electrode body 40 except for the tips of connection tabs 45 described later.
Therefore, the separator layers 36 and 46 are arranged around and between the layers of the negative electrode body 30 and the positive electrode body 40 in a state in which the negative electrode body 30 and the positive electrode body 40 are wound, and the negative electrode body 30 and the positive electrode body 40 are insulated from each other. separated. In FIG. 2, only the position of the negative electrode separator layer 36 is shown ignoring the layer thickness, and the positive electrode separator 46 is omitted. The positive electrode-side separator layer 46 is interposed between the negative electrode body 30 and the positive electrode body 40 over the entire region where the electrodes 40 face each other, and the negative electrode-side separator layer 36 covers the negative electrode body 30 . are placed to cover the
Hereinafter, the direction in which the negative electrode body 30 and the positive electrode body 40 are wound and stacked is referred to as a stacking direction. Note that winding means winding around a specific winding center axis.

The negative electrode body 30 is a sheet-like member including a foil-shaped negative electrode current collector made 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 made of, for example, 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 single substance or a mixture of silicon, silicon oxide, graphite, hard carbon, lithium titanate, and the like.
As materials for forming the negative electrode active material layer, in addition to the negative electrode active material, a conductive agent (e.g., graphite), a binder (e.g., dispersion of polyvinylidene fluoride or styrene-butadiene rubber (SBR), etc.), a thickener (e.g., , carboxymethyl cellulose (CMC), etc.) and a solvent (for example, an arbitrary solvent such as N-methylpyrrolidone) can be mixed to prepare a negative electrode slurry. A coating liquid containing constituent materials for forming a negative electrode active material layer can be referred to as a “negative electrode slurry”. A negative electrode active material layer can be formed by applying this negative electrode slurry to a negative electrode current collector and drying it.

The positive electrode body 40 is a sheet-like member including a foil-shaped positive electrode current collector made of a metal material and a positive electrode active material layer coated on one or both sides of the positive electrode current collector. be. The positive electrode current collector is made of, for example, metal foil such as aluminum or stainless steel. The thickness of the metal foil is, for example, about ten and several μm. The positive electrode active material is, for example, a composite oxide containing lithium and a transition metal, such as lithium cobaltate, lithium titanate, and lithium manganate.
As materials for forming the positive electrode active material layer, in addition to the positive electrode active material described above, a conductive aid (eg, graphite), a binder (eg, polyvinylidene fluoride, etc.), a solvent (eg, any solvent such as N-methylpyrrolidone). can be mixed to prepare a positive electrode slurry. A coating liquid containing constituent materials 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 the positive electrode slurry to the positive electrode side current collector and drying it.

The separator layers 36 and 46 are, for example, resin layers having lithium ion conductivity.
The separator layers 36 and 46 are made of a resin layer formed by applying the following paint to the required portions of the negative electrode body 30 and the positive electrode body 40 to form a coating film and curing the coating film.

As the paint 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 mixed with a solvent such as acetonitrile. You can use a paint dissolved in In addition, even if the paint itself does not have lithium ion conductivity, a material that can impart ionic conductivity by wetting the electrolyte may be used. For example, polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-hexafluoropropylene may be used. (PVDF-HFP) and a lithium salt added as a supporting salt to the electrolytic solution dissolved in a solvent such as acetone or N-methyl-2-pyrrolidone (NMP) may be used.
Furthermore, ionic conductivity may be imparted by mixing an inorganic substance into the resin contained in the paint. In this case, the inorganic material itself may have ionic conductivity, or the layer formed at the interface between the inorganic material and the resin may exhibit ionic conductivity.
As the inorganic substance to be added, aluminum oxide powder, titanium oxide powder, silicon oxide powder, zinc oxide powder, and magnesium oxide powder can be used singly or in mixture in various formulations. At this time, the particle size of the inorganic substance is preferably 5 nm to 1 μm.
The separator layers 36 and 46 can be formed by applying these paints to form a coating film, then removing the solvent by means of heating, light irradiation, drying, or the like, and curing the coating film. In addition, 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 powder into 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 in the housing portion 4 of the exterior body 2 at high density ( See Figure 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 unfolded state of the electrode laminate 3 will be described.
3 is a plan view showing an unfolded state of the negative electrode body 30 and the positive electrode body 40 of the first embodiment provided with a separator layer, and FIG. 4 is an unfolded state of the negative electrode body 30 and the positive electrode body 40 excluding the separator layer. It is a plan view showing the.
As shown in FIGS. 3 and 4, the negative electrode body 30 includes a plurality (eight in the illustrated example) of substantially circular negative electrode bodies 31 arranged in a row and a pair of adjacent negative electrode bodies 31 connected to each other. and at least one (seven in the illustrated example) electrode connection portions 32 , 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 stacking direction (see FIG. 2).
The electrode connection 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 when laminated (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 each of the front and back surfaces of the negative electrode main body 31 and the electrode connecting portion 32 . The negative electrode active material layer is not applied to the front and back surfaces of the tip portion of the negative electrode tab 35, and the negative electrode current collector is exposed.

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

The plurality of negative electrode main bodies 31 are arranged so that their centers in the negative electrode width direction overlap with each other when viewed from the negative electrode connecting direction. The plurality of negative electrode main bodies 31 are formed in a shape in which a part of a circle is missing. The negative electrode main body 31 excluding the eighth negative electrode main body 31H arranged on the outermost periphery of the negative electrode main body 31 has the entire linear portion 33 in the negative electrode connecting direction so that the dimension in the negative electrode connecting direction is gradually reduced with respect to the above-described basic shape. is provided near the central axis with respect to the basic shape.

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

The negative electrode tab 35 extends from the eighth negative electrode main body 31H to the side opposite to the first negative electrode main body 31A. The negative electrode tab 35 extends in the negative electrode connection direction with a width narrower than that of the plurality of electrode connection portions 32 .
In the negative electrode body 30 having the above structure, the entire portion except for the tip side of the negative electrode tab 35 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 main body 31 , the peripheral surface (side surface) and the front and back surfaces, as well as the side surfaces of the electrode connecting portion 32 , are covered with the negative electrode-side separator layer 36 .

As described above, the negative separator layer 36 is formed by curing a coating film. If paint is applied to the front and back surfaces of the negative electrode body 30 shown in FIG. , the negative electrode side separator layer 36 can be formed to cover almost the entire negative electrode body 30 except for the tip portion of the negative electrode tab 35 .
After the coating film is formed, if the paint is cured by heat, it should be heated to the curing temperature. In the case of coatings that are cured by intense irradiation and drying, the coating can be cured by drying at a suitable temperature. By curing the paint, a negative electrode body 30 having a structure covered with a separator layer 36 as shown in FIG. 3 can be obtained.

Next, the shape of the positive electrode body 40 in the unfolded state of the electrode laminate 3 will be described.
As shown in FIGS. 3 and 4, the positive electrode body 40 includes a plurality of (eight in the illustrated example) positive electrode bodies 41 arranged in a line and at least one ( The illustrated example has seven electrode connection portions 42 and positive electrode tabs 45 extending from the positive electrode main 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 connection portion 42 is a portion 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 a 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 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 main bodies 41 are arranged is referred to as the positive electrode connection direction (second direction), and the direction orthogonal to the positive electrode connection direction is referred to as the positive electrode width direction. In addition, in the positive electrode connection direction, the positive electrode main body 41 arranged on the outer peripheral side of the electrode laminate 3 with respect to the positive electrode main body 41 arranged on the winding center side of the laminated electrode body among the plurality of positive electrode main bodies 41 is " "Outer side" is defined, and the opposite direction is defined as "Inner side". In the following description, the plurality of positive electrode main bodies 41 and the plurality of electrode connection portions 42 will be described with ordinal numbers in the same manner as the negative electrode main body 31 and the electrode connection portions 32 .

The plurality of positive electrode bodies 41 are provided in the same number as the negative electrode bodies 31 . The plurality of positive electrode main bodies 41 are arranged so that their centers in the positive electrode width direction overlap each other when viewed from the positive electrode connection direction. Of the plurality of positive electrode bodies 41, the positive electrode bodies 41 excluding the first positive electrode body 41A arranged on the innermost circumference are formed smaller in external shape than the negative electrode bodies 31 facing each other with the separator layers 36, 46 interposed in the electrode laminate 3. It is For example, the outer shape of the seventh positive electrode body 41G is smaller than the outer shapes of the eighth negative electrode body 31H and the sixth negative electrode body 31F, which face each other with the separator layers 36, 46 interposed therebetween. The outer shape of the eighth positive electrode main body 41H is smaller than the outer shape of the seventh negative electrode main body 31G facing the positive electrode side separator layer 46 interposed therebetween.

As shown in FIGS. 3 and 4, the plurality of electrode connection portions 42 are provided between a pair of positive electrode main bodies 41 adjacent in the positive electrode connecting direction. Each electrode connection 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 connection direction with a width narrower than that of the plurality of electrode connection portions 42 .
In the positive electrode body 40 configured as described above, the entire portion except for the tip 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 main body 41 , the peripheral surfaces (side surfaces) and the front and back surfaces, as well as the side surfaces of the electrode connecting portion 42 , are covered with the positive electrode side separator layer 46 .

As described above, the positive electrode side separator layer 46 is formed by curing a coating film. If paint is applied to the front and back surfaces of the positive electrode body 40 shown in FIG. , the negative electrode side separator layer 46 can be formed to cover almost the entire positive electrode body 40 except for the tip portion of the positive electrode tab 45 .
After the coating film is formed, if the paint is cured by heat, it should be heated to the curing temperature. In the case of coatings that are cured by intense irradiation and drying, the coating can be cured by drying at a suitable temperature. By curing the paint, a positive electrode body 40 having a structure covered with a separator layer 46 as shown in FIG. 3 can be obtained.

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 negative electrode body 30 and the positive electrode body 40 are arranged in a straight line so that the connection tabs 35 and 45 face opposite directions. From this state, the negative electrode body 30 and the positive electrode body 40 are successively spirally wound in the same direction to form the electrode laminate 3 shown in FIG.

For example, first, the first electrode connecting portion 32A may be bent, and the first positive electrode main body 41A may be inserted between the layers of the first negative electrode main body 31A and the second negative electrode main body 31B to start winding. 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 connection portion 32A. be able to.
In any of the winding structures described above, 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

In addition, the dimension of each electrode connecting portion 32 in the negative electrode connection direction increases with increasing distance from the first negative electrode main body 31A.
Here, among the plurality of negative electrode bodies 31, except for the eighth negative electrode body 31H, attention is paid to a pair of negative electrode bodies 31 adjacent to each other in the unfolded state. The gap between the pair of negative electrode main bodies 31 in the wound state is such that the closer the pair of negative electrode main bodies 31 is to the outer peripheral side of the negative electrode main bodies 31, the more layers such as the negative electrode main bodies 31 disposed between the pair of negative electrode main bodies 31 are. As the number increases, it gets bigger. According to the present embodiment, the dimension of the electrode connection portion 32 in the first direction increases as the distance from the first electrode connection portion 32A increases. Mutual positional deviation in the rotating state can be suppressed. Therefore, positional displacement of the plurality of negative electrode bodies 31 is suppressed when viewed from the stacking direction, and the negative electrode body 30 can be wound into a desired flat shape.

Moreover, the dimension of each of the at least one electrode connection portions 32 in the negative electrode connection direction increases with increasing distance from the first electrode connection portion 32A. According to this configuration, of the pair of negative electrode main bodies 31, the negative electrode main body 31 on the outer peripheral side is formed to be larger in the negative electrode connection direction than the negative electrode main body 31 on the inner peripheral side. Therefore, in a state in which the plurality of negative electrode bodies 31 overlap each other, the negative electrode bodies 31 on the outer peripheral side are provided with non-overlapping regions where the negative electrode bodies 31 on the inner peripheral side do not overlap when viewed from the stacking direction.
By arranging the electrode connection part 32 connected to the negative electrode main body 31 on the inner peripheral side and extending in the stacking direction in the non-overlapping region of the negative electrode main body 31 on the outer peripheral side when viewed from the stacking direction, the electrode connection part 32 can be suppressed from protruding from the negative electrode main 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, misalignment of the plurality of negative electrode main bodies 31 and 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, and the flexibility of the shape is improved and the capacity is ensured.

When the strip-shaped negative electrode body 30 and the positive electrode body 40 shown in FIG. Rotating is also possible. However, when the negative electrode body 30 and the positive electrode body 40 are wound together with the film separator, winding misalignment may occur in one of them. If winding misalignment occurs in either the negative electrode body 30 or the positive electrode body 40 and the separator, the electrode body will protrude outside the separator somewhere in the outer peripheral portion of the electrode laminate, which increases the risk of internal short-circuiting. .
In this respect, if the winding structure of the negative electrode body 30 and the positive electrode body 40 is provided with the separator layers 36 and 46 formed by curing the coating film, even if the winding misalignment occurs in the negative electrode body 30 and the positive electrode body 40, There is no change in the fact that the separator layers 36 and 46 cover the negative electrode body 30 and the positive electrode body 40, respectively. Therefore, as long as the negative electrode body 30 provided with the negative electrode side separator layer 36 and the positive electrode body 40 provided with the positive electrode side separator layer 46 are wound, there is no risk of an internal short circuit. That is, if the electrode laminate 3 has a winding structure composed of the negative electrode body 30 and the positive electrode body 40 provided with the separator layers 36 and 46 made of the coating film cured layer, the battery (electrochemical cell) in which the risk of internal short circuit does not occur ) 1 can be provided.

In the structure of the first embodiment, the exterior body 2 housing the electrode laminate 3 is made of a laminate structure in which both sides of a metal foil such as an aluminum foil are covered with a resin layer. The bent portion 23 and the connection wall 12b are bent and press-molded and heat-sealed to form the sealing portion 5. As shown in FIG.
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, or the like will occur in the resin layer during press working. defective parts.

If these defective portions are formed, the electrolytic solution filled in the housing portion 4 may come into contact with the aluminum foil inside 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 this portion is close to or in contact with the aluminum foil in the outer package 2, and a negative electrode potential is applied to the aluminum foil. In this case, there is a possibility that deterioration of the negative electrode of the aluminum foil progresses due to contact between metallic lithium and aluminum. However, in the case of the electrode laminate 3 of the first embodiment, the separator layers 36 and 46 reliably cover the negative electrode body 30 and the positive electrode body 40. Therefore, defective portions are generated on the inner surface side of the outer package 2, and the aluminum foil is broken. Even if it is exposed, it does not advance the deterioration of the aluminum foil. Moreover, since the separator layers 36 and 46 reliably cover the negative electrode body 30 and the positive electrode body 40, it is possible to provide the battery (electrochemical cell) 1 in which the risk of internal short-circuiting is reduced.

In the present embodiment, when manufacturing the electrode laminate 3 by winding the negative electrode body 30 and the positive electrode body 40, the negative electrode body 30 and the positive electrode body 40 provided with the separator layers 36 and 46 after curing the paint are used. rolled.
On the other hand, instead of completely curing the coating film applied to form the separator layers 36 and 46, the electrode laminate 3 is formed by winding the negative electrode body 30 and the positive electrode body 40 in a semi-cured state. The separator layers 36, 46 may then be fully cured under the required curing conditions.

When the negative electrode body 30 provided with the semi-cured separator layers 36 and 46 and the positive electrode body 40 are wound, the semi-cured paint existing around the negative electrode body 30 and the semi-cured paint existing around the positive electrode body 40 during winding 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 together.
When the separator layers 36 and 46 are heat-treated in such a 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. It is possible to obtain the electrode laminate 3 which is cured as it is.
With the electrode layered body 3 having this structure, the electrode layered body 3 having a structure in which the periphery of the negative electrode body 30 and the positive electrode body 40 is more completely covered with the separator layers 36 and 46 can be obtained.

In the case of constructing the exterior body 2 shown in FIG. 1, as an example, the state before the bent portion 23 is formed on the upper side of the first peripheral wall portion 12 in the first container 10 by pressing is the bent portion 23. A ring plate-shaped flange is used. In addition, before forming the second peripheral wall portion 22 and the bent portion 23 on the outer peripheral side of the second bottom wall portion 21 in the second container 20 by press working, these are formed into a ring plate-shaped flange portion.
The above-described electrode laminate 3 is accommodated in 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-shaped portion is formed on 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 pressing with a punch having a projection. The details of the technique for pressing the flange portion are described in Japanese Patent Application Laid-Open No. 2018-85214 (Japanese Patent No. 6284248).

When the first container 10 and the second container 20 are formed from the above-described laminate structure, the shape of the outer package 2 is fixed when the first container 10 and the second container 20 are molded by pressing the flange portions. When the electrode laminate 3 enclosed inside is in a slightly swollen state, the exterior body 2 is in a slightly swollen state accordingly.
In order to avoid this state, during the above-described press working, or in a state where press for molding is separately performed after press working, the coating films constituting the separator layers 36 and 46 are heated to a temperature at which they are completely cured. A heat treatment is performed 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 semi-cured coating film from the shape-adjusted state of the exterior body 2, the shape as a whole is in a well-shaped state, and the electrode laminate 3 is entirely covered with the separator layers 36 and 46. Battery 1 can be obtained.
In particular, when the exterior body 2 is a laminate structure of a metal foil and a resin layer, the exterior body 2 is flexible in a state in which the electrode laminate 3 is accommodated, and the semi-cured coating film is present. Although the overall shape is not fixed, the overall shape of the battery 1 can be formed into a uniform and strong shape by adjusting the shape of the exterior body 2 and completely curing the coating film.

In addition, if the separator layer is formed by integrating a coating film cured layer individually covering the peripheral surface of the negative electrode body 30 and the peripheral surface of the positive electrode body 40, the negative electrode body 30 and the positive electrode body 40 are wound together. Even if the positive electrode body 40 is partially distorted, the negative electrode body 30 and the positive electrode body 40 are reliably covered with the separator layer. Moreover, the outer peripheral surface of the electrode laminate 3 in 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 the cross-sectional structure of a battery 50 of a second embodiment in which the electrochemical cell according to the present invention is applied to a secondary battery. This battery 50 is a circular button-shaped battery in plan view. A battery 50 according to 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 employed in the previous first embodiment. For this reason, with regard to the configuration of the exterior body 2, the same reference numerals are given to the same configurations as in the first embodiment, and detailed description of the same configurations will be omitted.
In the exterior body 2 of the second embodiment, the first container 10 and the second container 20 are formed of a laminate structure, have a storage portion 4, and are joined at the sealing portion 5. are equivalent. Also, a structure in which a second peripheral wall portion 22, a bent portion 23, and a connection wall 12b are formed in the joint portion 5, and the bent portion 23 and the connection wall 12b are heat-sealed by press working is also equivalent.

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 is formed by forming the negative electrode side separator layer 56 shown in FIG. ) on which the positive electrode side separator layer 58 shown in FIG. 6D is formed and wound in a spiral shape.
The negative electrode body 55 differs from the negative electrode body 30 used in the first embodiment in plan view shape, but has the same laminated structure. Although the visual shape is different, 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 front and back surfaces of a strip-shaped negative electrode current collector made of 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 front and back surfaces of a strip-shaped positive electrode current collector made of a metal foil such as aluminum. As the metal materials forming the negative electrode current collector and the positive electrode current collector, and the materials forming 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 form the separator layer 56 covering them, the same method as used for forming the separator layers 36 and 46 in the first embodiment is used. of 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 at one end in the length direction of the negative electrode current collector to expose the end of the negative electrode current collector, This exposed portion can be the 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 at one end in the length direction of the positive electrode current collector to expose the end of the positive electrode current collector, This exposed portion can be a connection tab 57a.

After the coating material for forming the separator layer is applied, heat treatment or the like is performed so that the coating film is cured or semi-cured as described in the first embodiment, and the negative electrode body 56 and the positive electrode body 57 are formed. 6(F), the electrode laminate 59 shown in FIG. 6(F) can be obtained.
After the laminate 59 is obtained, it is accommodated together with the electrolytic solution in the accommodating portion 4 consisting of the first container 10 and the second container 20 before being fused by press working, and the second peripheral wall portion 22 is bent by press working. A battery 50 having the structure shown in FIG. can.

If the battery 50 shown in FIG. 5 also has a winding structure of a negative electrode body 55 and a positive electrode body 57 provided with separator layers 56 and 58 obtained by curing a coating film, similarly to the battery 1 of the first embodiment, For example, even if winding misalignment occurs in the negative electrode body 55 and the positive electrode body 57 , 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 provided with the negative electrode side separator layer 56 and the positive electrode body 57 provided with the positive electrode side separator layer 58 are wound, there is no risk of an internal short circuit. That is, a battery (electrochemical cell) in which the risk of internal short-circuit does not occur if it is an electrode laminate 59 having a winding 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 layer. 50 can be provided.

Further, in the battery 50 shown in FIG. 5, the electrode laminate 53 having the semi-cured coating film is housed in the exterior body 2, and the separator layers 56 and 58 are completely cured by heat treatment after fusion bonding by press working. You can let me. In this case, it is possible to obtain the same effect as in the case of using the semi-cured coating film in the first embodiment described above.
In the second embodiment described above, in any of the winding structures described above, 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. It is oriented perpendicular to the wall portion 11 or the second bottom wall portion 21 .

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

The exterior body 62 has a circular shape in plan view. Specifically, the exterior body 62 includes a bottomed cylindrical positive electrode-side container 65 and a capped container 65 assembled to the positive electrode-side container 65 via a gasket 66 to define a storage space S between the positive electrode-side container 65 and the positive electrode-side container 65 . It has a cylindrical 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 will be referred to as the axis O, the side of the negative electrode side container 67 along the direction of the axis O will be referred to as the upper side, and the side of the positive side container 65 will be referred to as the lower side. The direction in which it rotates around the axis O is called the circumferential direction.

The positive electrode side container 65 and the negative electrode side container 67 are formed, for example, by drawing 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 is annular and arranged coaxially with the axis O, and is fitted in the peripheral wall portion 65 a of the positive electrode side container 65 . A groove portion 69 for holding the peripheral wall portion 67 a of the negative electrode side container 67 is formed in the gasket 66 over the entire circumference. The negative electrode side container 67 is fixed to the positive electrode side container 65 by crimping the upper end side of the peripheral wall portion 65a of the positive electrode side container 65 radially inward while holding the peripheral wall portion 67a in the groove portion 69 of the gasket 66. be.
The gasket 66 is made of an insulating material such as a resin material (eg, polypropylene (PP), polyphenylene sulfide (PPS), polyetheretherketone (PEEK)).

The electrode laminate 63 has a structure in which a plurality of disk-shaped negative electrode bodies 70 and positive electrode bodies 71 are laminated, which will be described below.
The negative electrode body 70 has a disk-shaped negative electrode current collector 72 and a negative electrode active material layer 73 applied on the upper surface thereof. there is
The positive electrode body 71 has a disk-shaped positive electrode current collector 76 and a positive electrode active material layer 77 applied on the upper surface thereof. there is

The negative electrode current collector 72 is made of the same material as the material constituting the negative electrode current collector of the negative electrode body 30 in the battery 1 of the first embodiment, such as copper foil. It is made of the same material as the material that constitutes the positive current collector of the positive electrode body 40, such as aluminum foil.
The negative electrode active material layer 73 is made of the same material as the material forming 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 material of the positive electrode body 40 in the battery 1 of the first embodiment. It consists of the same material as the material which comprised the positive electrode active material layer.

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

Although not shown in FIGS. 7 and 8, a connection conductor connected to all the negative electrode current collectors 72 provided in the electrode laminate 63 and conducting to the negative electrode side container 67 is provided inside the exterior body 62 . is provided, and connection conductors are provided that are connected to all the positive electrode current collectors 76 provided in the electrode laminate 63 and conduct to the positive electrode side container 63 .

The battery 60 described above has a structure in which the negative electrode active material layer 73 is covered with the negative electrode separator layer 75 and the positive electrode active material layer 77 is covered with the positive electrode separator layer 78 . Therefore, it is possible to provide a structure in which insulation is sufficiently separated by the negative electrode side separator layer 75 and the positive electrode side separator layer 78 .
By using the coating hardening 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-circuiting is unlikely to occur can be provided.

DESCRIPTION OF SYMBOLS 1... Battery (electrochemical cell), 2... Exterior body, 3... Electrode laminated body, 4... Accommodating part, 5... Sealing part, 10... First container (outer container), 11... First bottom wall part, 12 1st peripheral wall portion 12b connection wall 15 negative electrode plate 20 second container (inner container) 21 second bottom wall portion 22 second peripheral wall portion 23 bent portion 30 negative electrode Body 31 Electrode main body 32 Electrode connection portion 35 Connection tab 36 Negative electrode side separator layer 40 Positive electrode body 41 Electrode main body 42 Electrode connection portion 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 Layer 75... Negative electrode side separator layer 76... Positive electrode current collector 77... Positive electrode active material layer 78... Positive electrode side separator layer.

Claims (8)

At least one of the strip-shaped positive electrode body and the strip-shaped negative electrode body has a separator layer composed of a cured coating layer covering at least one surface, and the positive electrode body and the negative electrode body are wound around an arbitrary winding central axis. Equipped with an electrode laminate formed by turning,
The electrode laminate is accommodated in an exterior body that 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, folded, and fused together. ,
The separator layer is a separator layer obtained by fusing and integrating, in the wound state, coated film cured layers provided on peripheral surfaces including the strip-shaped positive electrode body and the strip-shaped negative electrode body including both front and back surfaces and side surfaces. electrochemical cell. At least one of the strip-shaped positive electrode body and the strip-shaped negative electrode body has a separator layer composed of a cured coating layer covering at least one surface, and the positive electrode body and the negative electrode body are wound around an arbitrary winding central axis. Equipped with an electrode laminate formed by turning,
The electrode laminate is accommodated in an exterior body in which the positive electrode can and the negative electrode can are integrated via a gasket,
The separator layer is a separator layer obtained by fusing and integrating, in the wound state, coated film cured layers provided on peripheral surfaces including the strip-shaped positive electrode body and the strip-shaped negative electrode body including both front and back surfaces and side surfaces. electrochemical cell. An extension is formed on a part of the positive electrode body and the negative electrode body, and a connection tab is formed on the distal end side of the extension, on which the separator layer composed of the coating film cured layer is not formed. 3. The electrochemical cell of claim 1 or claim 2. 2. The electrochemical cell according to claim 1, wherein the outer peripheral wall of the inner container and the outer peripheral wall of the outer container are composed of a laminate structure in which resin layers are provided on both sides of a metal foil. An extension portion is formed on a part of the positive electrode body and the negative electrode body, and a connection tab on which the separator layer made of the coating film cured layer is not formed is formed on the tip end side of the extension portion, and the inner container is provided with a connection tab. 2. The electrochemical cell according to claim 1, wherein the outer peripheral wall and the outer peripheral wall of the outer container are composed of a laminate structure in which a resin layer is provided on both sides of a metal foil . Each of the strip-shaped positive electrode body and the strip-shaped negative electrode body has a plurality of electrode bodies having a plan view shape similar to the plan view shape of the exterior body, and an electrode connection portion that connects the plurality of electrode bodies. ,
The positive electrode body and the negative electrode body are spirally wound and integrated with each other with the coating film cured layer interposed therebetween,
3. The electrode main body and the electrode connecting portion of the positive electrode body, and the electrode main body and the electrode connecting portion of the negative electrode body are both covered with a separator layer comprising the cured coating layer. An electrochemical cell according to any one of claims 1 to 5 . 7. The electrochemical cell according to claim 6, wherein both the electrode main body and the electrode connecting portion have active material layers on both front and back surfaces of current collector layers made of metal foil. In the method for manufacturing an electrochemical cell according to any one of claims 1 to 7, after forming a curable coating film on at least one surface of at least one of the strip-shaped positive electrode body and the strip-shaped negative electrode body, The positive electrode body and the negative electrode body are wound while the coating film is in a semi-cured state to form an electrode laminate. A method for producing an electrochemical cell, comprising curing a semi-cured coating.

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