Electrochemical cell and method for manufacturing an electrochemical cell

Abstract

To provide an electrochemical cell that enables a positive electrode and a negative electrode to be wound in a state in which the electrodes are kept in an appropriate relative positional relation so as to interpose a separator therebetween and has improved work reliability.SOLUTION: An electrochemical cell is provided which includes: an electrode body 2 that includes a separator 30, a positive electrode 10, and a negative electrode 20 and is wound to make the positive electrode and the negative electrode be superimposed on each other so as to interpose the separator therebetween; and an exterior body that stores the electrode body inside. At least either of the positive electrode and the negative electrode has a relative position with respect to the separator at the time of starting winding, the relative position positioned by a positioning part 100.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electrochemical cell and a method for manufacturing the same.

Background Art

[0002] Conventionally, electrochemical cells such as lithium-ion secondary batteries and electrochemical capacitors have been widely used as power sources for small devices such as wristwatches, smartwatches, smartphones, headsets, wearable devices, and hearing aids. In recent years, as a need for this type of electrochemical cell, the requirements for miniaturization and thinning have become even stronger. One of the reasons is that as ICs (integrated circuits) in various electronic devices in which electrochemical cells are mounted are miniaturized to an extremely fine level and their power consumption is reduced to achieve higher performance, electronic devices having high-spec functions that have not existed conventionally have begun to be proposed.

[0003] In this type of electrochemical cell, as an exterior body for housing an electrode body, for example, those using a metal case or those using a laminate film are known. The metal case includes, for example, a bottomed cylindrical case body and a sealing case for sealing the opening of the case body by caulking or the like via a gasket, and is often configured in a coin shape, a button shape, a cylindrical shape, or the like as a whole. On the other hand, when using a laminate film as the exterior body, the degree of freedom in shape can be increased, so it is easy to lead to miniaturization and high capacity of the electrochemical cell itself.

[0004] Also, as the electrode body, various structures are known. For example, as one of them, a wound structure formed by flatly winding a positive electrode and a negative electrode with a separator interposed therebetween is known. For example, in Patent Document 1 below, a positive electrode and a negative electrode are each formed in a strip shape in which a plurality of laminated surfaces are connected by a connecting piece, and the positive electrode and the negative electrode are flatly wound so as to be folded back by each connecting piece, whereby each laminated surface of the positive electrode and each laminated surface of the negative electrode are alternately laminated with a separator interposed therebetween. A secondary battery including an electrode body is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional secondary battery including the wound electrode body, for example, in order to secure a predetermined battery capacity, it is necessary that each laminated surface of the positive electrode and each laminated surface of the negative electrode are accurately opposed to each other with a separator interposed therebetween. However, in the above-described secondary battery, when the electrode body is wound, the position of the negative electrode may shift with respect to the positive electrode, and there is a risk of so-called winding deviation. In this case, it becomes difficult to wind the respective laminated surfaces of the positive electrode and the respective laminated surfaces of the negative electrode in a state where they are accurately opposed to each other with a separator interposed therebetween. Therefore, there is a risk of leading to a decrease in operating reliability, and there is room for improvement.

[0007] The present invention has been made in consideration of such circumstances, and an object thereof is to provide an electrochemical cell including an electrode body capable of winding a positive electrode and a negative electrode while maintaining an appropriate relative positional relationship with a separator interposed therebetween and having improved operating reliability, and a method for manufacturing the electrochemical cell.

Means for Solving the Problems

[0008] (1) The electrochemical cell according to the present invention includes a separator, a positive electrode, and a negative electrode, and has an electrode body in which the positive electrode and the negative electrode are overlapped with the separator sandwiched therebetween by being wound, and an exterior body that houses the electrode body therein. At least one of the positive electrode and the negative electrode is characterized in that the relative position at the start of winding with respect to the separator is positioned by a positioning portion.

[0009] According to the electrochemical cell of the present invention, by using the positioning portion, the relative position at the start of winding of at least one of the positive electrode and the negative electrode with respect to the separator can be positioned. Therefore, when the positive electrode and the negative electrode overlapped with each other with the separator sandwiched therebetween are wound to form an electrode body, it is possible to suppress the occurrence of so-called winding deviation in which the relative positional relationship between the positive electrode and the negative electrode with the separator sandwiched therebetween is displaced. As a result, the positive electrode and the negative electrode can be made into an electrode body that is accurately overlapped with the separator sandwiched therebetween, and an electrochemical cell with improved operating reliability can be obtained.

[0010] (2) The electrode body is wound flat so that the positive electrode and the negative electrode are alternately laminated with the separator interposed therebetween. The positive electrode includes a plurality of positive electrode bodies arranged along the lamination direction of the electrode body, and a plurality of positive electrode connection pieces connecting the plurality of positive electrode bodies to each other. The negative electrode includes a plurality of negative electrode bodies arranged along the lamination direction of the electrode body, and a plurality of negative electrode connection pieces connecting the plurality of negative electrode bodies to each other. The electrode body is wound so as to fold back the positive electrode connection piece and the negative electrode connection piece, so that the positive electrode body and the negative electrode body are arranged in a state of facing each other alternately in the lamination direction with the separator interposed therebetween. The positioning portion includes a first negative electrode body located on the winding start side among the plurality of negative electrode bodies, and a negative electrode positioning portion provided between the first negative electrode body and the separator for positioning the first negative electrode body with respect to the separator. The negative electrode positioning portion is arranged so as to be at least positioned between the outer end portion of the first negative electrode body facing the positive electrode connection piece with the separator interposed therebetween and the separator, and during charge and discharge, the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end portion through the separator may be made lower than the ionic conductivity of ions moving between the positive electrode body and the negative electrode body through the separator.

[0011] In this case, since the positioning of the first negative electrode body with respect to the separator can be performed using the negative electrode positioning portion, it is possible to form an electrode body in which a plurality of positive electrode bodies and a plurality of negative electrode bodies are alternately laminated in the lamination direction while being accurately opposed to each other with the separator interposed therebetween. As a result, an electrochemical cell with improved operating reliability can be obtained. In addition, since the negative electrode positioning portion is arranged to be at least located between the outer end portion of the first negative electrode body and the separator, the negative electrode current collector exposed to the outside at the outer end portion is arranged so as to protect it. And, during charging and discharging, the negative electrode positioning portion serves to reduce the ionic conductivity of ions (such as lithium ions, etc.) moving from the positive electrode connection piece toward the outer end portion through the separator, compared to the ionic conductivity of ions moving between the positive electrode body and the negative electrode body through the separator. Therefore, during charging and discharging, it is possible to suppress the movement of ions to the portion where the negative electrode current collector is exposed, and it is possible to make it difficult for inconveniences such as the deposition of ions in a needle shape on the negative electrode current collector to occur. Thus, the operating reliability can also be further improved by this fact.

[0012] (3) The negative electrode positioning portion is fixed to at least one of the first negative electrode body or the separator, and is an insulator that contacts the first negative electrode body and the separator, and may block the ion permeation holes formed in the separator.

[0013] In this case, since the negative electrode positioning portion is fixed to at least one of the first negative electrode body or the separator, the positioning of the first negative electrode body with respect to the separator can be surely performed, and it is possible to effectively suppress the occurrence of misalignment between the positive electrode and the negative electrode during winding. Further, since the negative electrode positioning portion is an insulator and can block the ion permeation holes by contacting the first negative electrode body and the separator, during charging and discharging, it is possible to effectively suppress the movement of ions from the positive electrode connection piece through the separator toward the outer end portion in the first negative electrode body, that is, the portion where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

[0014] (4) The negative electrode positioning portion is an insulating adhesive member that adheres the first negative electrode body and the separator to each other, and may block the ion permeation holes formed in the separator.

[0015] In this case, as the negative electrode positioning portion that is an insulator, for example, an adhesive member such as an insulating adhesive layer or an insulating adhesive tape can be used, so that it is easy to simplify the configuration and reduce the cost. In particular, since the adhesive member can block the ion permeation holes formed in the separator, during charge and discharge, ions can be effectively suppressed from moving from the positive electrode connection piece through the separator toward the outer end portion of the first negative electrode body, that is, the portion where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

[0016] (5) The negative electrode positioning portion may be a welded portion where the first negative electrode body and the separator are welded to each other, and the ion permeation holes formed in the separator by the welding may be blocked.

[0017] In this case, since the welded portion where the first negative electrode body and the separator are welded to each other functions as the negative electrode positioning portion, the positioning of the first negative electrode body with respect to the separator can be surely performed, and the occurrence of misalignment between the positive electrode and the negative electrode during winding can be effectively suppressed. Further, it is possible to surely block the ion permeation holes by partially melting the separator by the welding of the welded portion. Therefore, during charge and discharge, ions can be effectively suppressed from moving from the positive electrode connection piece through the separator toward the outer end portion of the first negative electrode body, that is, the portion where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

[0018] (6) The negative electrode positioning portion may be a separator welded portion where a part of the separator is preliminarily partially double-welded, and the ion permeation holes formed in the separator by the welding are blocked, and the first negative electrode body may be positioned with respect to the separator by contact of the outer end portion with respect to the separator welded portion.

[0019] In this case, a separator welded portion in which a part of the separator is partially pre-welded can be made to function as a negative electrode positioning portion. When the electrode body is wound, by bringing the outer end portion into contact with this separator welded portion, the first negative electrode body can be positioned with respect to the separator. Therefore, it is possible to suppress the occurrence of misalignment between the positive electrode and the negative electrode during winding. Furthermore, it is possible to surely block the ion permeation holes by partially melting the separator by welding the separator welded portion. Therefore, during charge and discharge, it is possible to effectively suppress the movement of ions from the positive electrode connection piece through the separator toward the outer end portion of the first negative electrode body, that is, the portion where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

[0020] (7) The negative electrode positioning portion may be an empty-wound portion in which a part of the separator is pre-wound, and the first negative electrode body may be positioned with respect to the separator by contact of the outer end portion with respect to the empty-wound portion.

[0021] In this case, an empty-wound portion in which a part of the separator is pre-wound can be made to function as a negative electrode positioning portion. When the electrode body is wound, by bringing the outer end portion into contact with this empty-wound portion, the first negative electrode body can be positioned with respect to the separator. Therefore, it is possible to suppress the occurrence of misalignment between the positive electrode and the negative electrode during winding. Furthermore, since it is possible to make it difficult for ions to pass through the amount of empty winding, during charge and discharge, it is possible to effectively suppress the movement of ions from the positive electrode connection piece through the separator toward the outer end portion of the first negative electrode body, that is, the portion where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

[0022] (8) The positioning portion may be provided between the positive electrode and the separator, and may include a positive electrode positioning portion that positions the first positive electrode body located on the winding start side among the plurality of positive electrode bodies with respect to the separator.

[0023] In this case, since the positioning of the first positive electrode body with respect to the separator can be performed using the positive electrode positioning portion, during winding, the first positive electrode body located on the starting side of the winding of the positive electrode and the first negative electrode located on the starting side of the winding of the negative electrode can be accurately aligned with each other with the separator interposed therebetween. Therefore, it is possible to more effectively suppress the occurrence of misalignment between the positive electrode and the negative electrode with the separator interposed therebetween during winding.

[0024] (9) The exterior body may be formed of a laminate film having a metal layer and resin layers covering both surfaces of the metal layer.

[0025] In this case, since the exterior body is formed of a laminate film having a metal layer and resin layers, it is possible to obtain a so-called laminate type electrochemical cell with excellent shape freedom, which is easy to use for various applications. Further, it is easy to seal the electrode body with high sealing performance, prevent the intrusion of dust, moisture, etc. from the outside, suppress the leakage of the contents inside the battery over a long period of time, and obtain an electrochemical cell with further improved operating reliability.

[0026] (10) The exterior body includes a support portion housed therein and arranged along the battery axis direction. The electrode body is wound around the support portion so that the positive electrode and the negative electrode are overlapped with each other with the separator interposed therebetween around the central axis of the support portion. The positioning portion includes a fixing portion for fixing the support portion and the separator. The positive electrode and the negative electrode may be positioned with respect to the support portion with the fixing portion as a reference, so that the relative position with respect to the separator is positioned.

[0027] In this case, the electrode body is wound around the support column portion, so that the positive electrode and the negative electrode are wound around the central axis of the support column portion with the separator sandwiched therebetween in a state where they are overlapped. In particular, when winding the electrode body using the support column portion, the fixing portion can be used to fix the support column portion and the separator, and the separator can be positioned with respect to the support column portion. Therefore, during winding, the positive electrode and the negative electrode can be positioned with respect to the support column portion with the fixing portion as a reference, so that the relative position with respect to the separator can be positioned. Therefore, it is possible to suppress the occurrence of so-called winding deviation in which the relative positional relationship between the positive electrode and the negative electrode is shifted with the separator sandwiched therebetween. As a result, the positive electrode and the negative electrode can be made into an electrode body that is accurately overlapped with the separator sandwiched therebetween, and an electrochemical cell with improved operating reliability can be obtained. Furthermore, since the winding core when winding the electrode body can be used as the support column portion, after forming the electrode body by winding, the electrode body together with the support column portion can be accommodated inside the outer package. Therefore, the assembly work can be efficiently performed, leading to an improvement in productivity.

[0028] (11) The outer package includes a bottom wall portion and a peripheral wall portion, and is a metal container body formed in a bottomed cylindrical shape, and a metal sealing plate that is welded and joined to the container body so as to close the opening of the container body and accommodates the electrode body between the container body and the sealing plate. At least a part of a current collecting plate exposed to the outside is welded to the sealing plate or the bottom wall portion via an insulating sealing material. The support column portion supports the sealing plate by having a first end in contact with the current collecting plate and a second end in contact with the sealing plate or the bottom wall portion. One of the positive electrode and the negative electrode may be electrically connected to the current collecting plate, and the other electrode may be electrically connected to the container body.

[0029] In this case, since the outer package is formed of a metal container body and a sealing plate, a so-called metal can type electrochemical cell can be obtained. In particular, the support portion is disposed so as to be sandwiched in the battery axial direction between the sealing plate and the bottom wall portion, the first end portion is in direct or indirect contact with the current collecting plate, and the second end portion is in direct or indirect contact with the sealing plate or the bottom wall portion of the container body. Thus, for example, when the first end portion of the support portion contacts the current collecting plate welded to the sealing plate via a sealing material and the second end portion of the support portion contacts the bottom wall portion of the container body, the sealing plate can be supported using the support portion. Differently, for example, even when the first end portion of the support portion contacts the current collecting plate welded to the bottom wall portion via a sealing material and the second end portion of the support portion contacts the sealing plate, the sealing plate can be supported using the support portion. In any case, the sealing plate can be supported using the support portion.

[0030] Therefore, even if the entire exterior body including the sealing plate is formed to be thin, unintended deformation such as the sealing plate being bent can be suppressed at the stage prior to the welding joint between the container body and the sealing plate. Therefore, the welding operation can be performed while suppressing displacement of the sealing plate with respect to the container body, etc., improving the working efficiency and leading to an improvement in productivity. Furthermore, the container body and the sealing plate can be welded appropriately with high precision, and reliable sealing performance can be obtained. Therefore, an electrochemical cell with high operating reliability and high quality can be obtained. Note that since one of the positive electrode and the negative electrode is electrically connected to the current collecting plate and the other electrode is electrically connected to the container body, the current collecting plate and the container body can be used as external connection terminals.

[0031] (12) The method for manufacturing an electrochemical cell according to the present invention has a positive electrode and a negative electrode that are stacked on top of each other with a separator therebetween, and the positive electrode and the negative electrode are alternately laminated with the separator therebetween by being flatly wound. The method includes an electrode body and an exterior body that houses the electrode body inside. The positive electrode includes a plurality of positive electrode main bodies arranged along the stacking direction of the electrode body, and a plurality of positive electrode connection pieces that connect the plurality of positive electrode main bodies to each other. The negative electrode includes a plurality of negative electrode main bodies arranged along the stacking direction of the electrode body, and a plurality of negative electrode connection pieces that connect the plurality of negative electrode main bodies to each other. The method for manufacturing an electrochemical cell is characterized in that an electrode body forming step is provided in which the positive electrode connection piece and the negative electrode connection piece are wound so as to be folded back, and the electrode body is formed such that the positive electrode main body and the negative electrode main body face each other alternately in the stacking direction with the separator therebetween. During the electrode body forming step, a positioning step is performed in which a first negative electrode main body located on the winding start side among the plurality of negative electrode main bodies is positioned with respect to the separator by providing a negative electrode positioning portion between the first negative electrode main body and the separator. During the positioning step, the negative electrode positioning portion is provided so as to be at least located between an outer end portion of the first negative electrode main body that faces the positive electrode connection piece with the separator therebetween and the separator. The negative electrode positioning portion is characterized in that the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end portion through the separator is made lower than the ionic conductivity of ions moving between the positive electrode main body and the negative electrode main body through the separator.

[0032] According to the method for manufacturing an electrochemical cell of the present invention, the first negative electrode main body can be positioned with respect to the separator by using the negative electrode positioning portion. Therefore, it is possible to suppress the occurrence of so-called winding deviation in which the relative positional relationship between the positive electrode and the negative electrode with the separator therebetween is displaced during the formation of the electrode body. Accordingly, it is possible to form an electrode body in which a plurality of positive electrode main bodies and a plurality of negative electrode main bodies are alternately laminated in the stacking direction while being accurately opposed to each other with the separator therebetween, and it is possible to manufacture an electrochemical cell with improved operating reliability. Moreover, since the negative electrode positioning portion is disposed at least between the outer end portion of the first negative electrode body and the separator, the negative electrode current collector exposed to the outside at the above-mentioned outer end portion can be protected. Moreover, the negative electrode positioning portion plays a role of reducing the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end portion through the separator, as compared with the ionic conductivity of ions moving between the positive electrode body and the negative electrode body through the separator during charge and discharge. Therefore, during charge and discharge, it is possible to suppress the movement of ions to the portion where the negative electrode current collector is exposed, and it is possible to make it difficult to cause inconveniences such as needle-like precipitation of ions on the negative electrode current collector.

[0033] (13) As the negative electrode positioning portion, an insulating adhesive member is used. During the positioning step, after applying the adhesive member on the outer end portion of the first negative electrode body or on the surface of the separator facing the outer end portion of the first negative electrode body, at least a part of the applied adhesive member is solidified or put into a wet state, and then the outer end portion of the first negative electrode body and the separator are adhered to each other to perform positioning.

[0034] In this case, in addition to using an insulating adhesive member as the negative electrode positioning portion, at least a part of the adhesive member after application is solidified or processed into an appropriate wet state. Thereby, when the first negative electrode body and the separator are brought into contact with each other, the slippage between the first negative electrode body and the separator can be effectively reduced. Therefore, in addition to the above-described operational effects, it is possible to effectively suppress the winding deviation when winding the positive electrode and the negative electrode overlapped with each other with the separator interposed therebetween to form an electrode body, and it is possible to more efficiently manufacture an electrochemical cell with improved operating reliability.

Effects of the Invention

[0035] According to the present invention, it is possible to wind the positive electrode and the negative electrode while maintaining an appropriate relative positional relationship with the separator interposed therebetween, and an electrochemical cell including an electrode body with improved operating reliability can be obtained.

Brief Description of the Drawings

[0036]

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Embodiments for Carrying Out the Invention

[0037] (First Embodiment) Hereinafter, a first embodiment of an electrochemical cell according to the present invention will be described with reference to the drawings. In the present embodiment, as an electrochemical cell, a lithium ion secondary battery (hereinafter simply referred to as a secondary battery), which is a kind of non-aqueous electrolyte secondary battery, will be described as an example. Further, in the present embodiment, a so-called laminated type secondary battery in which an exterior body is formed of a laminate film will be described as an example.

[0038] As shown in FIGS. 1 and 2, the secondary battery 1 of the present embodiment is a so-called coin type (button type) battery, and mainly includes an electrode body 2 having a plurality of electrodes laminated on each other in the stacking direction Z, that is, a positive electrode 10 and a negative electrode 20, and an exterior body 3 that houses the electrode body 2 therein. In each drawing, the electrode body 2 is illustrated in a simplified manner as appropriate.

[0039] As shown in FIGS. 3 and 4, the electrode body 2 includes a positive electrode 10, a negative electrode 20, and a separator 30. The electrode body 2 is a laminated type electrode of a winding structure type that is flattened and wound in a state where the positive electrode 10 and the negative electrode 20 are overlapped with the separator 30 interposed therebetween. As a result, the positive electrode 10 and the negative electrode 20 are arranged in a state of being alternately laminated in the stacking direction Z with the separator 30 interposed therebetween.

[0040] The electrode body 2 is formed so as to have a circular outer shape in a plan view. However, the outer shape of the electrode body 2 is not limited to this case, and other shapes such as an elliptical shape, an oval shape, or a rhombus shape may be used, and may be changed as appropriate. Note that the structure of the electrode body 2 will be described in detail later.

[0041] In the present embodiment, a case will be described as an example in which the stacking direction Z is the vertical direction, that is, the positive electrode 10 and the negative electrode 20 are stacked in the vertical direction. Further, an axis passing through the center of the electrode body 2 and extending along the stacking direction Z is referred to as a battery axis O1. In a plan view seen from the direction of the battery axis O1, the direction intersecting the battery axis O1 is referred to as a radial direction, and the direction of orbiting around the battery axis O1 is referred to as a circumferential direction.

[0042] (Outer package) As shown in FIGS. 1, 2, and 5, the outer package 3 is formed of a laminate film. The outer package 3 includes a first laminate member 40 and a second laminate member 50 that are laminated in the stacking direction Z with the electrode body 2 interposed therebetween. Thereby, the outer package 3 houses the electrode body 2 in a sealed state between the first laminate member 40 and the second laminate member 50. Note that an electrolyte solution (electrolyte) (not shown) is filled between the first laminate member 40 and the second laminate member 50.

[0043] The first laminate member 40 is a member that covers the electrode body 2 from above, and has a metal layer 41, and an inner resin layer 42 and an outer resin layer 43 that cover both surfaces of the metal layer 41. The inner resin layer 42 and the outer resin layer 43 are tightly joined to both surfaces of the metal layer 41 via a joining layer (not shown), for example, by heat fusion or adhesion. In each drawing except FIG. 5, the illustration of the metal layer 41, the inner resin layer 42, and the outer resin layer 43 is omitted.

[0044] The metal layer 41 is formed of a metal material suitable for blocking outside air and water vapor, such as stainless steel or aluminum. The inner resin layer 42 functions as an inner layer in the exterior body 3 and is formed using a thermoplastic resin such as polyethylene or polypropylene of polyolefin. As the polyolefin, for example, any of high-pressure low-density polyethylene (LDPE), low-pressure high-density polyethylene (HDPE), inflation polypropylene (IPP) film, unstretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, and linear low-chain branched polyethylene (L-LDPE, metallocene catalyst specification) can be used. In particular, polypropylene resin is preferred. The outer resin layer 43 functions as an outer layer in the exterior body 3 and is formed using, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

[0045] The first laminate member 40 includes a toped cylindrical housing portion 45 and a first sealing cylindrical portion 46 and is disposed coaxially with the battery axis O1. The housing portion 45 includes a cylindrical peripheral wall portion 47 that surrounds the electrode body 2 from the outside in the radial direction, and a top wall portion 48 that closes the upper end opening of the peripheral wall portion 47 and covers the electrode body 2 from above. The first sealing cylindrical portion 46 is formed in a cylindrical shape that surrounds the peripheral wall portion 47 from the outside in the radial direction. The lower end portion of the first sealing cylindrical portion 46 is formed to be integrally continuous with the lower end portion of the peripheral wall portion 47. That is, the first sealing cylindrical portion 46 is formed by folding back the peripheral wall portion 47 upward.

[0046] The second laminate member 50 is a member that covers the electrode body 2 from below and has a metal layer 51, and an inner resin layer 52 and an outer resin layer 53 that cover both surfaces of the metal layer 51. The inner resin layer 52 and the outer resin layer 53 are tightly joined to both surfaces of the metal layer 51 via a joining layer (not shown), for example, by heat fusion or adhesion. Note that the materials of the metal layer 51, the inner resin layer 52, and the outer resin layer 53 are the same as those of the metal layer 41, the inner resin layer 42, and the outer resin layer 43 in the first laminate member 40. Also, in each drawing except for FIG. 5, the illustration of the metal layer 51, the inner resin layer 52, and the outer resin layer 53 is omitted.

[0047] The second laminate member 50 is formed in a bottomed cylindrical shape including a cylindrical second sealing cylinder portion 56 that further surrounds the first sealing cylinder portion 46 from the outside in the radial direction, and a bottom wall portion 57 that closes the lower end opening of the second sealing cylinder portion 56 and covers the electrode body 2 from below, and is disposed coaxially with the battery axis O1.

[0048] The first laminate member 40 and the second laminate member 50 configured as described above are combined in a state where the electrode body 2 and the electrolyte solution are sealed inside by thermally welding the first sealing cylinder portion 46 and the second sealing cylinder portion 56 to each other. Specifically, the inner resin layer 42 in the first sealing cylinder portion 46 and the inner resin layer 52 in the second sealing cylinder portion 56 are thermally welded to each other.

[0049] Furthermore, as shown in FIG. 2, the secondary battery 1 of the present embodiment includes a first electrode plate 60, a second electrode plate 61, a first electrode terminal plate 62, a second electrode terminal plate 63, a first sealing film 64, and a second sealing film 65. The first electrode plate 60, the second electrode plate 61, the first electrode terminal plate 62, the second electrode terminal plate 63, the first sealing film 64, and the second sealing film 65 are housed inside the exterior body 3 together with the electrode body 2.

[0050] The first electrode plate 60, the first electrode terminal plate 62, and the first sealing film 64 are disposed between the electrode body 2 and the top wall portion 48 of the first laminate member 40. The second electrode plate 61, the second electrode terminal plate 63, and the second sealing film 65 are disposed between the electrode body 2 and the bottom wall portion 57 of the second laminate member 50.

[0051] The first electrode plate 60 is formed, for example, in a circular shape in plan view and is electrically connected to the positive electrode 10 in the electrode body 2. The first electrode plate 60 is formed of a metal material such as aluminum or stainless steel with a diameter smaller than that of the electrode body 2 and is disposed coaxially with the battery axis O1. On the lower surface of the first electrode plate 60, a positive electrode terminal tab 15 (to be described later) in the positive electrode 10 is joined, for example, by ultrasonic welding or the like. Thereby, the first electrode plate 60 is electrically connected to the positive electrode 10.

[0052] The first electrode terminal plate 62 is formed, for example, of a metal material such as nickel into a circular shape in plan view with a diameter smaller than that of the first electrode plate 60, and is disposed so as to overlap the upper surface of the first electrode plate 60 facing the first laminate member 40 side. Then, the first electrode terminal plate 62 is integrally joined to the upper surface of the first electrode plate 60, for example, by ultrasonic welding or resistance welding. Thereby, the first electrode plate 60 and the first electrode terminal plate 62 are electrically connected. Further, the first electrode terminal plate 62 may be a metal material such as copper having nickel formed on its surface. In this case, for example, the first electrode terminal plate 62 can be produced by performing nickel plating or the like. Furthermore, the first electrode terminal plate 62 may be partially formed on the first electrode plate 60 by nickel plating, thermal spraying, or the like. Note that the first electrode terminal plate 62 functions as an external connection terminal of the positive electrode 10.

[0053] A first through hole 48a for exposing the first electrode terminal plate 62 to the outside is formed in the top wall portion 48 of the first laminate member 40. The first through hole 48a is formed in a circular shape in plan view so as to penetrate the central portion of the top wall portion 48 vertically, and is formed coaxially with the battery axis O1.

[0054] The first sealant film 64 is formed in an annular shape surrounding the first electrode terminal plate 62 from the radially outer side, and is disposed coaxially with the battery axis O1 between the first electrode terminal plate 62 and the top wall portion 48 of the first laminate member 40 in a state of surrounding the first electrode terminal plate 62. The first sealant film 64 is thermally welded to the inner resin layer 42 of the top wall portion 48 in the first laminate member 40 and the upper surface of the first electrode plate 60, respectively. Thereby, the first electrode plate 60 is thermally welded to the top wall portion 48 of the first laminate member 40 via the first sealant film 64.

[0055] The first sealant film 64 is made of a thermoplastic resin such as polyolefin such as polyethylene or polypropylene, or a copolymer of a plurality of types of polyolefins, and contains a non-woven fabric made of polypropylene or the like. It is also possible to form the first sealant film 64 using a material in which these thermoplastic resins and the non-woven fabric are combined.

[0056] Since the first electrode plate 60, the first electrode terminal plate 62, and the first sealant film 64 are formed as described above, the entire surface of the first electrode terminal plate 62 is exposed upward through the first through-hole 48a.

[0057] The second electrode plate 61, the second electrode terminal plate 63, and the second sealant film 65 are formed and arranged in the same manner as the first electrode plate 60, the first electrode terminal plate 62, and the first sealant film 64 described above.

[0058] The second electrode plate 61 is formed in a circular shape in plan view and is electrically connected to the negative electrode 20 in the electrode body 2. The second electrode plate 61 is formed of a metal material such as copper with a diameter smaller than that of the electrode body 2 and is arranged coaxially with the battery axis O1. On the upper surface of the second electrode plate 61, a negative electrode terminal tab 25 (described later) in the negative electrode 20 is joined, for example, by ultrasonic welding. Thereby, the second electrode plate 61 is electrically connected to the negative electrode 20.

[0059] The second electrode terminal plate 63 is formed in a circular shape in plan view with a diameter smaller than that of the second electrode plate 61 using a metal material such as nickel, and is arranged on the lower surface of the second electrode plate 61 facing the second laminate member 50 side. The second electrode terminal plate 63 is integrally joined to the lower surface of the second electrode plate 61, for example, by ultrasonic welding or resistance welding. As a result, the second electrode plate 61 and the second electrode terminal plate 63 are electrically connected. Also, the second electrode terminal plate 63 may be made of a metal material such as copper with nickel formed on its surface. In this case, for example, the second electrode terminal plate 63 can be manufactured by performing nickel plating or the like. Furthermore, the second electrode terminal plate 63 may be partially formed on the second electrode plate 61 by nickel plating, thermal spraying, or the like. Note that the second electrode terminal plate 63 functions as an external connection terminal of the negative electrode.

[0060] A second through-hole 57a for exposing the second electrode terminal plate 63 to the outside is formed in the bottom wall portion 57 of the second laminate member 50. The second through-hole 57a is formed in a circular shape in plan view so as to penetrate the central portion of the bottom wall portion 57 vertically and is formed coaxially with the battery axis O1.

[0061] The second sealant film 65 is formed in an annular shape surrounding the second electrode terminal plate 63 from the radially outer side, and is arranged coaxially with the battery axis O1 between the second electrode terminal plate 63 and the bottom wall portion 57 of the second laminate member 50 in a state of surrounding the second electrode terminal plate 63. The second sealant film 65 is thermally welded to the inner resin layer 52 of the bottom wall portion 57 and the lower surface of the second electrode plate 61 in the second laminate member 50, respectively. As a result, the second electrode plate 61 is thermally welded to the bottom wall portion 57 of the second laminate member 50 via the second sealant film 65.

[0062] Note that the second sealant film 65 is made of a thermoplastic resin such as polyolefin such as polyethylene or polypropylene, or a copolymer of a plurality of types of polyolefin, like the first sealant film 64, and contains a non-woven fabric made of polypropylene or the like. Also, it is possible to form the second sealant film 65 using a material in which these thermoplastic resins and the non-woven fabric are combined.

[0063] As described above, since the second electrode plate 61, the second electrode terminal plate 63, and the second sealant film 65 are formed, the entire surface of the second electrode terminal plate 63 is exposed downward through the second through hole 57a.

[0064] (Electrode body) The electrode body 2 will be described in detail. As shown in FIGS. 3, 4, and 6, the electrode body 2 is formed by flatly winding the positive electrode 10 and the negative electrode 20 with the separator 30 interposed therebetween. Therefore, the positive electrode 10 and the negative electrode 20 are wound around the winding axis O2 together with the separator 30. As shown in FIG. 3, the electrode body 2 is wound around the winding axis O2 that intersects the battery axis O1, and is housed inside the exterior body 3 while maintaining this state.

[0065] As shown in FIG. 7, the positive electrode 10 includes a positive current collector 11 (positive current collecting foil) formed in a strip shape extending along the first direction L1 in the unfolded state before winding, and positive electrode active material layers 12 (see FIG. 6) formed on both surfaces of the positive current collector 11 by coating or the like, and is formed in a single sheet shape. In FIG. 7, the illustration of the positive electrode active material layer 12 is omitted.

[0066] The positive current collector 11 is formed in a thin sheet shape from a metal material such as aluminum or stainless steel. The positive electrode active material layer 12 is formed on portions of both surfaces of the positive current collector 11 excluding the positive electrode terminal tab 15 described later. This positive electrode active material layer 12 contains a positive electrode active material, a conductive auxiliary agent, a binder, a thickening agent, and the like. As the positive electrode active material, for example, lithium cobaltate (LCO), nickel-manganese-cobalt lithium oxide (NMC), or the like can be used.

[0067] Examples of the conductive aid include carbon blacks, carbon materials, metal fibers, metal fine powders, etc. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

[0068] The positive electrode 10 includes a plurality of positive electrode bodies 13 and a plurality of positive electrode connection pieces 14. The positive electrode body 13 is formed in a disc shape in the unfolded state of the positive electrode 10 and is arranged at intervals so as to be aligned in a row in the first direction L1. In the illustrated example, the number of the positive electrode bodies 13 is 10. However, the number of the positive electrode bodies 13 is not limited to 10 and may be appropriately changed. The positive electrode body 13 is a portion that is overlapped with respect to the negative electrode body 23 described later so as to face in the stacking direction Z with the separator 30 interposed therebetween.

[0069] The positive electrode connection piece 14 is arranged between the positive electrode bodies 13 adjacent to each other in the first direction L1 in the unfolded state of the positive electrode 10 and connects the adjacent positive electrode bodies 13. Therefore, in the illustrated example, the number of the positive electrode connection pieces 14 is 9. The positive electrode connection piece 14 is a portion that is folded back at the side portion of the electrode body 2 by winding. Further, the width of the positive electrode connection piece 14 along the second direction L2 orthogonal to the first direction L1 in plan view is formed shorter than the width of the positive electrode body 13 along the second direction L2. In particular, the dimension of each positive electrode connection piece 14 along the first direction L1 is larger for the positive electrode connection piece 14 arranged on the outer peripheral side in the electrode body 2 in the wound state. As a result, the interval between the positive electrode bodies 13 adjacent to each other in the first direction L1 in the unfolded state becomes larger as the position is closer to the outer peripheral side in the wound state.

[0070] Of the plurality of positive electrode bodies 13, in the electrode body 2 in the wound state, the positive electrode body 13 disposed on the innermost circumferential side is referred to as the inner circumferential side positive electrode body (the first positive electrode body according to the present invention) 13A, and the positive electrode body 13 disposed on the outermost circumferential side is referred to as the outer circumferential side positive electrode body 13B. Therefore, the inner circumferential side positive electrode body 13A corresponds to the positive electrode body 13 located on the winding start side.

[0071] Furthermore, on the outer circumferential side positive electrode body 13B, in the developed state of the positive electrode 10, a positive electrode terminal tab 15 is formed so as to further extend outward in the first direction L1. As described above, on both sides of this positive electrode terminal tab 15, the positive electrode active material layer 12 is not formed, and it is electrically connected to the lower surface of the first electrode plate 60. Note that the positive electrode terminal tab 15 is electrically connected to the first electrode plate 60 in a state where it is folded back with the connection portion to the outer circumferential side positive electrode body 13B as a base point.

[0072] As shown in FIG. 8, the negative electrode 20 includes a negative electrode current collector 21 (negative electrode current collecting foil) formed in a strip shape extending along the first direction L1 in the developed state before winding, and negative electrode active material layers 22 (see FIG. 6) formed on both surfaces of the negative electrode current collector 21 by coating or the like, and is formed in a single sheet shape. Note that in FIG. 8, the illustration of the negative electrode active material layer 22 is omitted.

[0073] The negative electrode current collector 21 is formed in a thin sheet shape of a metal material such as copper, nickel, and stainless steel. The negative electrode active material layer 22 is formed on portions of both surfaces of the negative electrode current collector 21 excluding the negative electrode terminal tab 25 described later. This negative electrode active material layer 22 contains a negative electrode active material, a conductive auxiliary agent, a binder, a thickener, and the like, and is formed of a carbon material such as natural or artificial graphite.

[0074] Examples of the conductive assistant include carbon blacks, carbon materials, metal fibers, metal fine powders, and the like. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

[0075] The negative electrode 20 includes a plurality of negative electrode bodies 23 and a plurality of negative electrode connection pieces 24. The negative electrode body 23 is formed in a disc shape in the same manner as the positive electrode body 13 in the developed state of the negative electrode 20, and is arranged at intervals so as to be aligned in a row in the first direction L1. In the illustrated example, the number of the negative electrode bodies 23 is 10 corresponding to the number of the positive electrode bodies 13. However, the number of the negative electrode bodies 23 is not limited to 10, and may be appropriately changed corresponding to the number of the positive electrode bodies 13.

[0076] The negative electrode connection piece 24 is arranged between the adjacent negative electrode bodies 23 in the first direction L1 in the developed state of the negative electrode 20, and connects the adjacent negative electrode bodies 23 to each other. Therefore, in the illustrated example, the number of the negative electrode connection pieces 24 is 9. The negative electrode connection piece 24 is a portion that is folded back at the side portion of the electrode body 2 by winding. Further, the width of the negative electrode connection piece 24 along the second direction L2 orthogonal to the first direction L1 in plan view is formed shorter than the width of the negative electrode body 23 along the second direction L2.

[0077] In particular, the dimension of each negative electrode connection piece 24 along the first direction L1 is larger for the negative electrode connection piece 24 arranged on the outer peripheral side in the wound electrode body 2. As a result, the interval between the adjacent negative electrode bodies 23 in the first direction L1 in the developed state becomes larger as the position is closer to the outer peripheral side in the wound state.

[0078] Of the plurality of negative electrode bodies 23, in the electrode body 2 in the wound state, the negative electrode body 23 disposed on the innermost circumferential side is referred to as an inner circumferential side negative electrode body (first negative electrode body according to the present invention) 23A, and the negative electrode body 23 disposed on the outermost circumferential side is referred to as an outer circumferential side negative electrode body 23B. Therefore, the inner circumferential side negative electrode body 23A corresponds to the negative electrode body 23 located on the winding start side.

[0079] Furthermore, on the outer circumferential side negative electrode body 23B, a negative electrode terminal tab 25 is formed so as to further extend outward in the first direction L1 in the unfolded state of the negative electrode electrode 20. As described above, this negative electrode terminal tab 25 has no negative electrode active material layer 22 formed on both of its surfaces and is electrically connected to the upper surface of the second electrode plate 61. Note that the negative electrode terminal tab 25 is electrically connected to the second electrode plate 61 in a state of being folded back with the connection portion to the outer circumferential side negative electrode body 23B as a base point.

[0080] The negative electrode electrode 20 configured as described above has an outer shape that is an equivalent similar shape to the outer shape of the positive electrode electrode 10 described above. However, the outer size of the positive electrode electrode 10 is formed slightly smaller (one size smaller) than the outer size of the negative electrode electrode 20.

[0081] The separator 30 shown in FIG. 4 is formed of, for example, a resin microporous film such as polyolefin, a non-woven fabric made of glass or resin, a laminate of fibers such as cellulose fibers, etc., and is capable of allowing lithium ions to pass through ion permeation holes (not shown). The separator 30 is disposed throughout the layer between the positive electrode electrode 10 and the negative electrode electrode 20 and insulates between the positive electrode electrode 10 and the negative electrode electrode 20. Therefore, the separator 30 is disposed so as to intervene between the positive electrode electrode 10 and the negative electrode electrode 20 at least throughout the region where the positive electrode electrode 10 and the negative electrode electrode 20 face each other.

[0082] Note that, in the state before the separator 30 is wound around the electrode body 2, it is formed, for example, in a sheet shape wider than the positive electrode 10 and the negative electrode 20, and after winding, it is formed into a shape corresponding to the positive electrode 10 and the negative electrode 20 by processing such as cutting.

[0083] As described above, the positive electrode 10 and the negative electrode 20 configured as such are wound with the separator 30 interposed therebetween, as shown in FIG. 4, so as to be alternately laminated. An example of the process (electrode body forming process) of forming the electrode body 2 in which the positive electrode 10 and the negative electrode 20 are laminated in this way will be described below. For example, the positive electrode 10 and the negative electrode 20 are arranged along the first direction L1 such that the positive electrode tab 15 and the negative electrode tab 25 are arranged on opposite sides of each other, and the positive electrode 10 and the negative electrode 20 are combined such that the inner peripheral side positive electrode body 13A and the inner peripheral side negative electrode body 23A overlap with each other with the separator 30 interposed therebetween. Next, as shown in FIG. 9, starting from the inner peripheral side positive electrode body 13A and the inner peripheral side negative electrode body 23A that are overlapped with each other, the positive electrode 10 and the negative electrode 20 are repeatedly wound in the same direction. Note that the illustration of the separator 30 is omitted in FIG. 9. Thereby, the positive electrode body 13 and the negative electrode body 23 can be laminated in the lamination direction Z so as to be alternately overlapped, and the electrode body 2 shown in FIG. 4 can be obtained.

[0084] Note that the positive electrode tab 15 and the negative electrode tab 25 only need to be arranged in opposite directions when the positive electrode 10 and the negative electrode 20 are wound to form the electrode body 2, and do not necessarily need to be arranged in opposite directions at the winding start stage as described above. For example, as shown in FIG. 10, winding may be started after the positive electrode 10 and the negative electrode 20 are overlapped with the separator 30 interposed therebetween in a state where the positive electrode tab 15 and the negative electrode tab 25 face the same direction. Note that the illustration of the separator 30 is omitted in FIG. 10.

[0085] Furthermore, as shown in FIG. 11, the electrode body 2 may be formed by winding the positive electrode 10, the negative electrode 20, and the separator 30 using a winding machine 70 having a winding core 71. The rewinder 70 mainly includes a winding core 71 and a pair of touch rolls 72. The winding core 71 is formed in a flat plate shape extending with a predetermined width along the winding axis O2 and is rotatable around the winding axis O2. A slit groove 71a is formed in the winding core 71 along the winding axis O2. The pair of touch rolls 72 are arranged on opposite sides of each other with the winding core 71 interposed therebetween and are arranged so as to be able to approach and separate from the winding axis O2.

[0086] When performing winding using the rewinder 70 configured as described above, first, the winding core 71 is rotated about half a turn with the belt-shaped separator sheet 31 passed through the slit groove 71a of the winding core 71. As a result, the separator sheet 31 is wound around both sides of the winding core 71 sandwiching the slit groove 71a, and the separator sheet 31 can be arranged in a Z shape when viewed from the direction along the winding axis O2. Note that the separator sheet 31 is a sheet that later functions as the separator 30.

[0087] Next, the positive electrode 10 and the negative electrode 20 are arranged on both sides sandwiching the winding core 71. At this time, the inner peripheral side positive electrode body 13A of the positive electrode 10 is set so as to overlap the separator sheet 31, and the inner peripheral side negative electrode body 23A of the negative electrode 20 is set so as to overlap the separator sheet 31. Then, by rotating the winding core 71 around the winding axis O2 in this state, the positive electrode 10, the negative electrode 20, and the separator sheet 31 can be wound around the winding core 71 and wound flatly around the winding axis O2.

[0088] As a result, a wound body can be obtained in which a plurality of positive electrode bodies 13 and a plurality of negative electrode bodies 23 are respectively arranged in parallel with the winding core 71, and a plurality of positive electrode connection pieces 14 and a plurality of negative electrode connection pieces 24 are respectively folded along the side edge portions of the winding core 71. During winding, the pair of touch rolls 72 are constantly in contact with the wound body, enabling tight winding of the positive electrode 10, the negative electrode 20, and the separator sheet 31. Finally, after pulling out the winding core 71 from the wound body in the direction of the winding axis O2, by cutting off the unnecessary portions of the separator sheet 31, the electrode body 2 shown in FIG. 4 can be formed.

[0089] Incidentally, in the present embodiment, as shown in FIG. 6, the separator 30 is provided with a positioning portion 100 for positioning the relative position at the start of winding of at least one of the positive electrode 10 and the negative electrode 20. Specifically, the positioning portion 100 is provided between the inner peripheral side negative electrode body 23A located on the start side of winding among the plurality of negative electrode bodies 23 constituting the negative electrode 20 and the separator 30 in the wound electrode body 2, and includes a negative electrode positioning portion for positioning the inner peripheral side negative electrode body 23A with respect to the separator 30. The negative electrode positioning portion is an insulating adhesive layer (adhesive member according to the present invention) 80 that adheres the inner peripheral side negative electrode body 23A and the separator 30 to each other. Since the adhesive layer 80 is provided between the inner peripheral side negative electrode body 23A and the separator 30, it is possible to integrally combine and position the inner peripheral side negative electrode body 23A with respect to the separator 30.

[0090] In particular, the adhesive layer 80 is provided so as to be positioned between the outer end portion of the inner peripheral side negative electrode body 23A that faces the positive electrode connection piece 14 with the separator 30 interposed therebetween. At the outer end portion of the inner peripheral side negative electrode body 23A, due to the winding relationship between the positive electrode 10 and the negative electrode 20, the negative electrode current collector 21 is exposed in a state facing the separator 30 side. In this regard, as described above, since the adhesive layer 80 is disposed between the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30, the adhesive layer 80 covers the negative electrode current collector 21 that is exposed to the outside as if protecting it.

[0091] Moreover, since the adhesive layer 80 covers the surface of the separator 30, it blocks the ion permeation holes formed in the separator 30. As a result, during charge and discharge of the secondary battery 1, the adhesive layer 80 reduces the ionic conductivity of lithium ions that move from the positive electrode connection piece 14 through the separator 30 toward the outer end of the inner peripheral side negative electrode body 23A as indicated by the arrow F1 in FIG. 6, compared to the ionic conductivity of lithium ions (i.e., lithium ions that essentially contribute to charge and discharge) that move between the positive electrode body 13 and the negative electrode body 23 through the separator 30 as indicated by the arrow F2 in FIG. 6.

[0092] Note that the adhesive layer 80 can be formed, for example, as shown in FIG. 12, by applying an adhesive 81 in advance to the outer end of the inner peripheral side negative electrode body 23A when winding the positive electrode 10, the negative electrode 20, and the separator 30, that is, when performing the electrode body forming process. In FIG. 12, only the separator 30 and the negative electrode 20 are shown. Thereby, a positioning process can be performed to position the outer end of the inner peripheral side negative electrode body 23A with respect to the separator 30. However, it is not limited to this case. For example, as shown in FIG. 13, an adhesive 81 can be applied in advance to the separator 30 side, and the adhesive layer 80 can be formed by adhering the outer end of the inner peripheral side negative electrode body 23A to the separator 30 through the adhesive 81.

[0093] Note that the adhesive 81 only needs to have at least insulation properties and is not limited to a specific one. For example, it preferably has properties such as little swelling property with respect to an electrolyte solution (electrolyte), excellent adhesion property to a metal, flexibility with respect to winding, a wide potential window, and stable material properties with respect to oxidation and reduction potentials. Specifically, as the adhesive 81, a polyacrylic acid-based resin, an ester-based resin of polyacrylic acid, or the like can be preferably employed. Furthermore, it is also possible to preferably use a copolymer in which a part of the skeleton of these resins is substituted with styrene as the adhesive 81. More specifically, it is possible to use "Polyzol L300 (registered trademark)" manufactured by Showa Denko K.K. as the adhesive 81.

[0094] During the positioning process described above, after applying the adhesive 81 to the outer end of the inner peripheral side negative electrode body 23A, when the negative electrode 20 is placed in contact with the separator 30, it is preferable to solidify the surface or inside of the adhesive 81 in advance, or to perform a treatment so as to achieve an appropriate wet state. When the adhesive 81 is the above-mentioned resin, as a method of solidifying, for example, a method of volatilizing the solvent by heating or the like to dry it, or a method of chemically polymerizing by heat treatment, irradiation with ultraviolet rays (UV), or the like can be used.

[0095] Moreover, an appropriate wet state refers to a state in which the adhesive 81 is such that the solvent is volatilized by the above-mentioned method and the amount of the contained solvent is suppressed, but it does not reach the state of being solidified. By forming such an adhesive layer 80, when the negative electrode 20 is placed in contact with the separator 30, the slippage between the negative electrode 20 and the separator 30 can be reduced. As a result, when forming the electrode body 2 thereafter, the winding deviation described later can be effectively suppressed.

[0096] In addition, as the material of the adhesive layer 80, in addition to the above-mentioned adhesive 81, copolymers such as polyvinylidene fluoride (PVDF) and vinylidene fluoride - hexafluoropropylene copolymer (PVDF - HFP), and resins such as polyimide can be used. When using these materials, after diluting with a solvent and gelling in advance, apply it to the outer end of the inner peripheral side negative electrode body 23A, and then solidify it by completely drying or semi - drying, or perform a treatment so as to achieve an appropriate wet state, and then form the subsequent electrode body 2. Among these materials, for PVDF, N-methylpyrrolidone (NMP) or the like can be used as a solvent. Also, for PVDF-HFP, acetone or the like can be used as a solvent. These solvents are dried before assembling the cell (secondary battery 1). When using polyimide, a polyamic acid or the like, which is a precursor thereof, can be applied to the outer end portion of the inner peripheral side negative electrode body 23A and polymerized by heating or the like for use.

[0097] (Operation of the secondary battery) According to the secondary battery 1 configured as described above, as shown in FIG. 2, the first electrode terminal plate 62 electrically connected to the first electrode plate 60 is exposed to the outside, and the second electrode terminal plate 63 electrically connected to the second electrode plate 61 is exposed to the outside. Therefore, these first electrode terminal plate 62 and second electrode terminal plate 63 can function as external connection terminals respectively. Thereby, it becomes possible to use the secondary battery 1 by utilizing the first electrode terminal plate 62 and the second electrode terminal plate 63.

[0098] In particular, according to the secondary battery 1 of the present embodiment, since the electrode body 2 is formed by winding the positive electrode 10 and the negative electrode 20, in a state where the electrode body 2 is wound in a flat shape without a protruding portion, it can be accommodated at a high density inside the exterior body 3. Therefore, the degree of freedom in shape can be improved, and the volume ratio of the electrode body 2 to the entire volume of the secondary battery 1 can be improved, and a laminated type secondary battery 1 with improved volume efficiency can be obtained.

[0099] Furthermore, as shown in FIG. 6, it is provided with a positioning portion 100 including an adhesive layer 80 that functions as a negative electrode positioning portion. In particular, by using the adhesive layer 80, the positioning of the inner peripheral side negative electrode body 23A with respect to the separator 30 can be performed. Therefore, when winding the positive electrode 10 and the negative electrode 20 that are overlapped with each other with the separator 30 interposed therebetween to form the electrode body 2, it is possible to suppress the occurrence of so-called winding deviation in which the relative positional relationship between the positive electrode 10 and the negative electrode 20 shifts with the separator 30 interposed therebetween. As a result, as shown in FIG. 4, the electrode body 2 can be formed by alternately laminating a plurality of positive electrode bodies 13 and a plurality of negative electrode bodies 23 in the stacking direction Z while accurately opposing each other with the separator 30 interposed therebetween. Therefore, the secondary battery 1 with improved operating reliability can be obtained.

[0100] In addition, as shown in FIG. 6, the adhesive layer 80 is disposed so as to be positioned between the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30, thereby protecting the negative electrode current collector 21 exposed to the outside at the outer end portion. Moreover, the adhesive layer 80 closes the ion permeation holes in the separator 30, so that during charge and discharge, the ionic conductivity of lithium ions moving from the positive electrode connection piece 14 toward the outer end portion through the separator 30 is lower than the ionic conductivity of lithium ions moving between the positive electrode body 13 and the negative electrode body 23 through the separator 30.

[0101] Therefore, during charge and discharge, it is possible to suppress the movement of lithium ions to the portion where the negative electrode current collector 21 is exposed, and it is possible to make it difficult for inconveniences such as the precipitation of lithium ions in a needle shape (dendrite growth) on the negative electrode current collector 21 to occur. Therefore, the operating reliability of the secondary battery 1 can be further improved by this as well.

[0102] As described above, according to the secondary battery 1 of the present embodiment, it is possible to wind the positive electrode 10 and the negative electrode 20 while maintaining an appropriate relative positional relationship with the separator 30 interposed therebetween, and a laminate type battery including the electrode body 2 with improved operating reliability can be obtained. Furthermore, since the adhesive layer 80 can function as a negative electrode positioning portion, it is easy to simplify the configuration and reduce the cost.

[0103] (First Modified Example) In the above-described first embodiment, the case where the adhesive layer 80 is used as the negative electrode positioning portion has been described as an example, but the present invention is not limited to this case. For example, instead of the adhesive layer 80, an insulating adhesive tape (adhesive member according to the present invention) may be used. Even in this case, the same operational effects can be achieved.

[0104] (Second Modified Example) Furthermore, the negative electrode positioning portion is not limited to the case of using an adhesive member such as the adhesive layer 80 or the adhesive tape described above. For example, the positioning of the inner peripheral side negative electrode body 23A with respect to the separator 30 may be performed by welding.

[0105] Specifically, as shown in FIG. 14, a welded portion 85 formed by welding the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30 to each other may function as the negative electrode positioning portion. In FIG. 14, only the negative electrode 20 and the separator 30 are illustrated. In this case, when winding the positive electrode 10, the negative electrode 20, and the separator 30, it is possible to form the welded portion 85 by performing welding at the beginning of winding. As the welding, for example, high-frequency welding, thermal welding, ultrasonic welding, etc. can be used.

[0106] Thus, even when the welded portion 85 is used, the same operational effects as those of the above-described embodiment can be achieved. In particular, by welding the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30 to each other, the separator 30 can be partially melted to surely block the ion permeation holes. Therefore, the ionic conductivity of lithium ions moving from the positive electrode connection piece 14 toward the outer end portion of the inner peripheral side negative electrode body 23A through the separator 30 can be effectively reduced. Thereby, the operating reliability of the secondary battery 1 can be further improved.

[0107] Also, in the case of welding, it is not limited to the case where the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30 are welded to each other. As shown in FIG. 15, a separator welded portion 86 may be formed by partially and preliminarily double-welding a part of the separator 30, and this separator welded portion 86 may function as a negative electrode positioning portion. In FIG. 15, only the negative electrode 20 and the separator 30 are shown. In this case, when winding the positive electrode 10, the negative electrode 20, and the separator 30, a separator 30 with a separator welded portion 86 formed in advance is prepared. Then, at the beginning of winding, as shown by the arrow in FIG. 15, the negative electrode 20 is combined with the separator 30 so that the outer end portion of the inner peripheral side negative electrode body 23A contacts the separator welded portion 86, and then winding may be performed.

[0108] Thereby, the inner peripheral side negative electrode body 23A can be positioned with respect to the separator 30, so that it is possible to suppress the occurrence of misalignment between the positive electrode 10 and the negative electrode 20 during winding. Further, even in this case, as shown in FIG. 16, the separator welded portion 86 can partially melt the separator 30 to surely block the ion permeation holes, so that the ion conductivity of lithium ions moving from the positive electrode connection piece 14 through the separator 30 toward the outer end portion of the inner peripheral side negative electrode body 23A can be effectively reduced, and the operating reliability of the secondary battery 1 can be further improved.

[0109] (Third Modified Example) Furthermore, in the above first embodiment, as shown in FIG. 17, a positioning portion 100 may be provided between the positive electrode 10 and the separator 30 and may include a positive electrode positioning portion for positioning the inner peripheral side positive electrode body 13A with respect to the separator 30. In the illustrated example, mainly after wrapping the upper and lower surfaces of the inner peripheral side positive electrode body 13A with the separator 30, the upper and lower surfaces of the separator 30 are welded along the positive electrode connection piece 14 connected to the inner peripheral side positive electrode body 13A to form a positive electrode side welded portion 87, so that the positive electrode side welded portion 87 functions as a positive electrode positioning portion. Note that in FIG. 17, only the positive electrode 10 and the separator 30 are illustrated.

[0110] Thereby, by using the positive electrode side welding portion 87, it becomes possible to position the inner peripheral side positive electrode body 13A with respect to the separator 30. Subsequently, as shown in FIG. 18, in the same manner as in the above embodiment, an adhesive layer 80 is formed by adhering the outer end portion of the inner peripheral side negative electrode body 23A and the separator 30 to each other using an adhesive 81, thereby positioning the inner peripheral side negative electrode body 23A with respect to the separator 30. At this time, the separator 30 and the negative electrode 20 are combined using the adhesive layer 80 so that the outer end portion of the inner peripheral side negative electrode body 23A overlaps the positive electrode side welding portion 87.

[0111] By doing as described above, during winding performed thereafter, the inner peripheral side positive electrode body 13A located on the winding start side of the positive electrode 10 and the inner peripheral side negative electrode body 23A located on the winding start side of the negative electrode 20 can be accurately aligned with the separator 30 interposed therebetween. Therefore, it is possible to more effectively suppress the occurrence of misalignment between the positive electrode 10 and the negative electrode 20 with the separator 30 interposed therebetween during winding.

[0112] Note that the positive electrode side welding portion 87 is not limited to being formed by welding the upper and lower surfaces of the separator 30 along the positive electrode connection piece 14. For example, the upper and lower surfaces of the separator 30 may be partially welded so as to sandwich the positive electrode connection piece 14.

[0113] (Fourth Modification Example) Furthermore, as a negative electrode positioning portion, as shown in FIG. 19, a part of the separator 30 may be a pre-wound empty winding portion 88. In this case, for example, when winding is performed using the winder 70 shown in FIG. 11, the winding core 71 may be rotated a predetermined number of times in advance around the winding axis O2 to perform only the empty winding of the separator 30. Thereby, when combining the negative electrode 20 with the separator 30, the negative electrode 20 can be combined with reference to the empty winding portion 88. That is, at the beginning of winding, the negative electrode 20 can be combined with the separator 30 such that the outer end portion of the inner peripheral side negative electrode body 23A contacts the empty winding portion 88.

[0114] Thereby, the inner peripheral side negative electrode body 23A can be positioned with respect to the separator 30, so that it is possible to suppress the occurrence of misalignment between the positive electrode 10 and the negative electrode 20 during winding. Furthermore, even in this case, since it is possible to make it difficult for lithium ions to pass from the positive electrode connection piece 14 toward the outer end portion of the inner peripheral side negative electrode body 23A by the amount of empty winding, it is similarly possible to reduce the ionic conductivity of lithium ions.

[0115] (Fifth Modification Example) In the above first embodiment, the second electrode plate 61 is made of copper, but it may be made of nickel, for example. In this case, it is also possible to omit the second electrode terminal plate 63. That is, on the negative electrode side, an electrode terminal plate is not necessarily essential and may not be provided. In this case, the second electrode plate 61 itself can function as an external connection terminal on the negative electrode side.

[0116] (Sixth Modification Example) Furthermore, in the above first embodiment, the secondary battery 1 having a circular shape in plan view has been described as an example, but the shape of the secondary battery 1 may be appropriately changed. For example, it may be a secondary battery having an oval shape in which a straight portion and a semicircular portion are combined in plan view. In this case, the shape of the electrode body 2 may be configured to be oval in plan view corresponding to the outer shape of the secondary battery.

[0117] (Seventh Modification Example) Furthermore, in the above-described first embodiment, the peripheral wall portion 47 of the first laminate member 40 is made to function as the accommodating portion 45, but the present invention is not limited to this case. For example, as shown in FIG. 20, the second laminate member 50 may be formed to have a peripheral wall portion 58, and the secondary battery 90 may be configured such that the peripheral wall portion of the accommodating portion 45 is constituted by the peripheral wall portion 58 and the peripheral wall portion 47 of the first laminate member 40. In this case, the sealing portion constituted by the first sealing cylinder portion 46 and the second sealing cylinder portion 56 may be formed so as to surround the peripheral wall portion 47 of the first laminate member 40 over the entire circumference from the outer side in the radial direction. Even in the case of the secondary battery 90 configured in this way, the same operational effects can be achieved.

[0118] (Eighth Modification Example) Furthermore, in the above-described first embodiment, as shown in FIG. 21, the negative electrode connection piece 24 connected to the inner peripheral side negative electrode body 23A may be folded back, and the inner peripheral side negative electrode body 23A and the negative electrode body 23 adjacent to the inner peripheral side negative electrode body 23A in the unfolded state may be overlapped in the stacking direction Z in advance with the separator 30 interposed therebetween. In the electrode body 2 in this case, since the outer end portion of the inner peripheral side negative electrode body 23A and the negative electrode connection piece 24 face each other with the separator 30 interposed therebetween, it becomes possible to prevent lithium ions from moving from the positive electrode 10 side toward the outer end portion of the inner peripheral side negative electrode body 23A during charge and discharge.

[0119] (Ninth Modification Example) Furthermore, in the above-described first embodiment, it is not necessary for the entire exterior body 3 to be formed of a laminate film, and at least a part thereof may be formed of a laminate film. Furthermore, the present invention is not limited to the case where the exterior body 3 is formed of a laminate film, and it may be a metal casing. In this case, the electrochemical cell according to the present invention can be a so-called button-type battery made of metal, and can be used as a battery having high versatility. An example of the case where the exterior body is made of metal will be described in the following second embodiment.

[0120] (Second Embodiment) Next, a second embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. As shown in FIGS. 22 to 24, the secondary battery 110 of this embodiment is a so-called button (coin) type battery, and includes a metal exterior body 112, a power generation element 113 and a support column portion 114 housed inside the exterior body 112.

[0121] The exterior body 112 includes a metal container body 120 formed in a bottomed cylindrical shape, and a metal lid member (sealing plate according to the present invention) 130 that is welded and joined to the container body 120 so as to close the opening of the container body 120 and forms an accommodation space 115 between the container body 120. The power generation element 113 includes an electrode body 140 having a positive electrode 142 and a negative electrode 143 disposed with a separator 141 therebetween, contains an electrolyte solution (not shown), and is housed in an accommodation space 115 formed inside the exterior body 112.

[0122] In this embodiment, an axis extending vertically through the center of the exterior body 112 is referred to as a battery axis O1. Also, in a plan view seen from the direction of the battery axis O1, the direction intersecting the battery axis O1 is referred to as a radial direction, and the direction of orbiting around the battery axis O1 is referred to as a circumferential direction. Further, along the battery axis O1, the direction from the bottom wall portion 121 of the container body 120 toward the lid member 130 is referred to as upward, and the opposite is referred to as downward.

[0123] (Exterior Body) The exterior body 112 will be described in detail. The container body 120 is formed in a bottomed cylindrical shape including a bottom wall portion 121 formed in a circular shape in plan view, and a peripheral wall portion 122 continuously provided along the entire circumference of the outer peripheral edge portion of the bottom wall portion 121 and extending upward from the bottom wall portion 121. However, the shape of the container body 120 is not limited to a bottomed cylindrical shape, and for example, it may be formed so that the outer shape is elliptical, rectangular, or polygonal in plan view.

[0124] The container body 120 is made of metal and functions as an external connection terminal for the positive electrode or the negative electrode that conducts to the electrode body 140. The thickness of the container body 120 is, for example, about 0.01 mm to 0.30 mm, and it is a thin-walled metal container. However, in each drawing, the thickness of the container body 120 is exaggerated for easy viewing.

[0125] The specific metal material of the container body 120 varies depending on whether the container body 120 functions as an external connection terminal for the positive electrode or the negative electrode. For example, aluminum, aluminum alloy, copper, copper alloy, stainless steel, or a clad material (high-functional metal material) formed by crimping the same or different metals can be used. However, it is not limited to these cases. Examples of stainless steel include ferritic stainless steels such as SUS430 and SUS444, and austenitic-ferritic duplex stainless steels such as SUS329J4L.

[0126] Examples of clad materials include a three-layer clad material of Cu (inner layer) / Fe (middle layer) / Ni (outer layer), a three-layer clad material of Ni (inner layer) / Fe (middle layer) / Ni (outer layer), a three-layer clad material of Al (inner layer) / SUS (middle layer) / Ni (outer layer), etc. However, the clad material is not limited to three layers, and it may be formed by crimping other metals in multiple layers.

[0127] When Cu is used as the clad material, the thermal conductivity can be increased, so the heat dissipation during welding can be improved. Therefore, it is preferable to adopt Cu in the inner layer of the clad material because it can lead to the protection of the electrode body 140.

[0128] Furthermore, it is preferable to perform plating treatment on either the inner surface or the outer surface of the clad material, or both the inner surface and the outer surface to form a metal plating film. By forming a metal plating film on the inner surface of the container body 120, it can be chemically stabilized and the resistance to electrolytic solution and the like can be improved. Also, by forming a metal plating film on the outer surface of the container body 120, functions such as a rust prevention function can be added, and the electrical resistance can be reduced, so that the electrical connectivity with the external terminal can be improved.

[0129] In addition, as the specific metal plating film, for example, a Ni plating film, an alloy plating film such as Ni alloy, etc. can be adopted, and it is particularly preferable to adopt an alloy plating film of eutectic metal material. When an alloy plating film of eutectic metal material is adopted, for example, the melting point can be lowered when performing resistance welding, and the temperature during welding can be lowered. In addition, alloy plating films such as Au-Ni alloy plating film, Ni-P alloy plating film, Ni-B alloy plating film, etc. can also be preferably adopted.

[0130] Also, for example, when the secondary battery 110 of the present embodiment is used for clock applications, the metal material of the container body 120 is preferably non-magnetic in addition to being corrosion-resistant. Specifically, in addition to the above-mentioned aluminum, aluminum alloy, copper, and copper alloy, as stainless steel, for example, various austenitic stainless steels such as SUS201, SUS202, SUS303, SUS304, SUS305, SUS316, SUS317, SUS321, SUS347 can be mentioned. Furthermore, as the container body 120, a material in which a resin layer is formed on the surface of the above-mentioned various metals may be adopted. For example, a laminate film in which a metal layer made of stainless steel and a film-like resin layer are laminated can be used. In this case, the opening of the container body 120 can be closed by joining the metal lid member 130 and the metal layer of the container body 120. As the resin layer, for example, the resin material adopted for the sealant film 150 described later can be used.

[0131] As shown in FIGS. 23 and 24, the lid member 130 is formed in a circular shape in plan view, and is disposed facing the bottom wall portion 121 of the container body 120 across the electrode body 140 in the direction of the battery axis O1. It is formed in a toped cylindrical shape including a top wall portion 131 and an inner peripheral wall portion 132 that is continuously provided over the entire outer peripheral edge portion of the top wall portion 131 and extends upward from the top wall portion 131.

[0132] Note that the shape of the lid member 130 only needs to correspond to the shape of the container body 120, and may be formed, for example, in an elliptical shape, a rectangular shape, or a polygonal shape in plan view corresponding to the shape of the container body 120. The thickness of the lid member 130 is, for example, about 0.01 mm to 0.30 mm, similar to the container body 120, and is made thin. However, in each drawing, the thickness of the lid member 130 is exaggerated for easy viewing.

[0133] The lid member 130 is disposed inside the peripheral wall portion 122 such that the top wall portion 131 is positioned below the upper end opening edge of the peripheral wall portion 122 of the container body 120, and the upper end opening edge of the peripheral wall portion 122 and the upper end opening edge of the inner peripheral wall portion 132 are flush. Thereby, the inner peripheral wall portion 132 is welded and joined in a state of being radially double - overlapped inside the peripheral wall portion 122 of the container body 120.

[0134] The peripheral wall portion 122 and the inner peripheral wall portion 132 are firmly joined by welding over the entire circumference. Thereby, the opening of the container body 120 can be closed using the lid member 130, and an accommodation space 115 (sealed space) for accommodating the support portion 114 and the power generation element 113 is formed between the container body 120.

[0135] The welding method between the container body 120 and the lid member 130 is not particularly limited, and for example, resistance welding such as laser welding, ultrasonic bonding, seam welding, or friction stir welding (FSW) can be adopted. During these welds, welding may be performed in a so-called workpiece movement method in which the side of the outer casing 112, which is the workpiece to be welded, is moved while the side of the welding machine (not shown) is fixed, or in a so-called head movement method in which the side of the outer casing 112, which is the workpiece to be welded, is fixed and welding is performed while moving the side of the welding machine. For example, when performing laser welding in the head movement method, it is possible to employ a galvanoscanning type laser welder or the like.

[0136] In the central portion of the lid member 130, a through hole 133 that penetrates the lid member 130 in the vertical direction is formed coaxially with the battery axis O1. The shape of the through hole 133 is not particularly limited, but for example, it is formed in a circular shape in plan view.

[0137] The lid member 130 configured as described above is made of metal. As a specific metal material of the lid member 130, for example, the same or different metal materials as those of the container body 120 can be employed. When employing a different metal material from the container body 120 as the metal material of the lid member 130, it is preferable to employ a material having a thermal expansion coefficient approximate to that of the container body 120. Furthermore, similar to the container body 120, it is preferable to perform plating treatment on either one of the inner surface and the outer surface, or both the inner surface and the outer surface of the lid member 130 to form a metal plating film. As the metal plating film, the metal plating film described above can be employed.

[0138] (Current collector plate) As shown in FIGS. 22 to 24, the lid member 130 configured as described above is thermally welded (welded) via a sealant film (the insulating sealing material according to the present invention) 150, and a current collector plate 151 having at least a part thereof exposed to the outside (upward) is provided. Specifically, the sealant film 150 and the current collector plate 151 are disposed on the upper surface side of the top wall portion 131 of the lid member 130 that faces the opposite direction of the battery axis O1 from the accommodation space 115. Then, the current collector plate 151 is thermally welded to the upper surface of the top wall portion 131 via the sealant film 150 and is exposed upward over the entire surface.

[0139] The sealing film 150 is formed in an annular shape surrounding the through hole 133 formed in the top wall portion 131, and is disposed so as to overlap the upper surface of the top wall portion 131 in a state of being coaxial with the battery axis O1. In the illustrated example, the sealing film 150 is formed with an inner diameter smaller than the diameter of the through hole 133. However, it is not limited to this case, and the inner diameter of the sealing film 150 may be formed to be equal to or larger than the diameter of the through hole 133.

[0140] The sealing film 150 is formed of, for example, a thermoplastic resin made of polyolefin or an engineering plastic such as polyphenylene sulfide (PPS). Examples of polyolefin include polyethylene, polypropylene, polybutene, and the like. Furthermore, as the sealing film 150, a copolymer or blend polymer of each of the above-mentioned polyolefins, or a composite such as polypropylene reinforced with a non-woven fabric may be used. Furthermore, a plurality of sealing films 150 having different dimensions, shapes, or thicknesses may be stacked and used.

[0141] The current collector plate 151 is a metal plate and functions as an external connection terminal for the positive electrode or an external connection terminal for the negative electrode that conducts to the electrode body 140. In the illustrated example, the current collector plate 151 is formed in a circular shape in plan view with a diameter smaller than the outer diameter of the sealing film 150, and is disposed so as to overlap the upper surface of the sealing film 150 in a state of being coaxial with the battery axis O1. Thereby, the current collector plate 151 closes the through hole 133 from above.

[0142] The material of the current collector plate 151 is not particularly limited, but for example, nickel or the like can be preferably used. Furthermore, on the surface of the current collector plate 151 that can be externally connected, a metal made of a good electrical conductivity material such as gold or nickel, or an alloy plating film containing these metals may be formed.

[0143] The above-mentioned sealant film 150 is thermally welded to the upper surface of the top wall portion 131 and the lower surface of the current collector plate 151, respectively. As a result, the current collector plate 151 is thermally fused to the upper surface of the top wall portion 131 via the sealant film 150, and airtightly seals the through hole 133 from above while maintaining insulation from the lid member 130. In particular, the current collector plate 151 is integrally combined with the lid member 130 via the sealant film 150.

[0144] Here, the sealant film 150 insulates the current collector plate 151 and the container body 120. In the secondary battery 110 of the present embodiment, the current collector plate 151 and the container body 120 can be electrically connected to either the positive terminal or the negative terminal of the electronic device by contacting a contact pressure terminal, a holder, etc. of the electronic device (not shown). Further, after a metal terminal is further welded to at least one of the current collector plate 151 and the container body 120, it may be electrically connected to the electronic device by soldering, welding, or the like.

[0145] (Support column portion) As shown in FIGS. 23 and 24, a support column portion 114 is accommodated in the accommodation space 115 in the exterior body 112 together with the power generation element 113. The support column portion 114 is formed in an axial shape extending in the vertical direction along the battery axis O1 and is arranged coaxially with the battery axis O1. In the illustrated example, the support column portion 114 is formed in a hollow cylindrical shape, and its outer diameter is smaller than the diameter of the through hole 133 and the inner diameter of the sealant film 150. As a result, the support column portion 114 is arranged such that its upper end portion (the first end portion according to the present invention) contacts the current collector plate 151 from below through the through hole 133, and its lower end portion (the second end portion according to the present invention) contacts the bottom wall portion 121 of the container body 120 from above. Therefore, the support column portion 114 supports the current collector plate 151, which is integrally combined with the lid member 130, from below. That is, the support column portion 114 supports the lid member 130 from below via the current collector plate 151.

[0146] The support portion 114 of this embodiment is formed of an insulating material such as an inorganic material like ceramic or a synthetic resin material. When the support portion 114 is made of a synthetic resin, for example, a thermoplastic resin having a melting point equivalent to that of the separator 141 can be preferably used. Specifically, materials such as synthetic resins such as PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), and PBT (polybutylene terephthalate) can be adopted. Furthermore, copolymers or blend polymers of these synthetic resins can also be utilized. Thereby, electrical connection between the container body 120 and the current collector plate 151 through the support portion 114, electrical connection between the current collector plate 151 and the electrode body 140, and electrical connection between the container body 120 and the electrode body 140 are suppressed.

[0147] (Power generation element) As shown in FIGS. 23 and 24, the power generation element 113 includes an electrode body 140 and an electrolyte (not shown), and is hermetically accommodated in the accommodation space 115 inside the exterior body 112 together with the support portion 114 described above. As the electrolyte, for example, a liquid in which a supporting salt is dissolved in a non-aqueous solvent can be preferably used. As the supporting salt, for example, lithium hexafluorophosphate (LiPF6) can be used. As the solvent, for example, a low-boiling solvent can be used together with ethylene carbonate (EC).

[0148] However, instead of the electrolyte, the power generation element 113 may adopt an electrode body 140 using an electrolyte such as a solid electrolyte, a polymer electrolyte, or a gel electrolyte. Examples of the polymer electrolyte include polyethylene oxide (PEO), polypropylene oxide (PPO), blend polymers containing them, polyacrylate esters, polymethacrylate esters, polysiloxanes, polyphosphazenes, etc. Also, a gel electrolyte containing poly(vinylidene fluoride-co-hexafluoropropylene, PVdF-HFP) in the electrolyte may be used.

[0149] (Electrode body) As shown in FIG. 23, the electrode body 140 has a positive electrode 142 and a negative electrode 143 disposed with a separator 141 interposed therebetween, and is a wound electrode wound multiple times around the battery axis O1. Specifically, the electrode body 140 is wound around the support portion 114 so that the positive electrode 142 and the negative electrode 143 are overlapped with the separator 141 interposed therebetween, and is configured to be wound multiple times in the radial direction around the central axis C (see FIG. 4) of the support portion 114 disposed coaxially with the battery axis O1. Therefore, the support portion 114 also functions as a winding core when winding the electrode body 140.

[0150] In a plan view seen from the direction of the battery axis O1, the electrode body 140 is wound in a multiple spiral shape around the battery axis O1 (the central axis C of the support portion 114). In the present embodiment, from the innermost layer located on the support portion 114 side to the outermost layer located on the peripheral wall portion 122 side of the container body 120 in the electrode body 140, the negative electrode 143, the separator 141, the positive electrode 142, the separator 141, the negative electrode 143, the separator 141, and the positive electrode 142 are repeatedly arranged in this order and wound. Note that the electrode body 140 may be, for example, a so-called pellet-type electrode body 140 having a positive electrode 142 and a negative electrode 143 on both sides of the separator 141. Also, in each drawing other than FIG. 23, the illustration of the electrode body 140 is simplified.

[0151] As shown in FIG. 25, the positive electrode 142 is formed in a single sheet shape including a long positive current collector (positive current collecting foil) 142a formed to extend in a strip shape with a constant width in an unfolded state before winding of the electrode body 140, and a positive active material layer 142b formed on one or both sides of the positive current collector 142a by coating or the like.

[0152] The positive current collector 142a is formed of a thin sheet-like (metal foil) metal material such as aluminum, an aluminum alloy, stainless steel, etc. The thickness of the positive current collector 142a is, for example, about several μm to ten-odd μm. The positive electrode active material layer 142b is formed on a portion of the positive current collector 142a excluding the positive electrode terminal tab 142c described later. In addition to the metal foil, for the positive current collector 142a, for example, an etching foil, a punching metal, a sintered metal body, or a foamed metal body can be used.

[0153] As a material for forming the positive electrode active material layer 142b, in addition to the positive electrode active material, a conductive assistant (for example, carbon black, graphite, etc.), a binder (for example, polyvinylidene fluoride, etc.), and a solvent (for example, an arbitrary solvent such as N-methylpyrrolidone) can be mixed to prepare a positive electrode slurry. Note that a coating liquid containing constituent materials for forming the positive electrode active material layer 142b can be referred to as "positive electrode slurry". By applying this positive electrode slurry to the positive current collector 142a and drying it, the positive electrode active material layer 142b can be formed. Examples of the positive electrode active material include composite oxides containing lithium and transition metals such as lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium titanate (LTO), and lithium manganate (LMO).

[0154] A positive electrode terminal tab 142c is formed at one end of the positive current collector 142a located on the side away from the support portion 114 among both ends. As described above, the positive electrode active material layer 142b is not formed on the positive electrode terminal tab 142c, and it is electrically connectable to other components. The positive electrode terminal tab 142c is disposed on the outer layer side of the electrode body 140 when the electrode body 140 is wound.

[0155] As shown in FIG. 25, the negative electrode 143 is formed in a single sheet shape including a long negative electrode current collector (negative electrode current collector foil) 143a formed to extend in a strip shape with a constant width in the unfolded state before winding of the electrode body 140, and a negative electrode active material layer 143b formed on one or both surfaces of the negative electrode current collector 143a by coating or the like.

[0156] The negative electrode current collector 143a is formed of a thin sheet (metal foil) of a metal material such as copper, copper alloy, nickel, and stainless steel. The thickness of the negative electrode current collector 143a is, for example, about several μm to ten-odd μm. The negative electrode active material layer 143b is formed on a portion of the negative electrode current collector 143a excluding a negative electrode terminal tab 143c described later. In addition to the metal foil, for example, an etching foil, punching metal, sintered metal body, or foamed metal body can be used as the negative electrode current collector 143a.

[0157] As a material for forming the negative electrode active material layer 143b, in addition to the negative electrode active material, a conductive assistant (for example, carbon black, graphite, etc.), a binder (for example, a dispersion of styrene-butadiene rubber (SBR), etc.), a thickener (for example, cellulose nanofiber (CNF), carboxymethyl cellulose, etc.), and a solvent (for example, any solvent such as pure water) can be mixed to prepare a negative electrode slurry. Note that a coating liquid containing constituent materials for forming the negative electrode active material layer 143b can be referred to as a "negative electrode slurry". The negative electrode active material layer 143b can be formed by applying this negative electrode slurry to the negative electrode current collector 143a and drying it. Examples of the negative electrode active material include a single substance or a mixture such as silicon, silicon oxide, graphite, hard carbon, lithium titanate (LTO), and LiAl.

[0158] At one end of the negative electrode current collector 143a, which is located on the side away from the support portion 114 among both end portions, a negative electrode terminal tab 143c is formed. As described above, the negative electrode terminal tab 143c has no negative electrode active material layer 143b formed thereon and is electrically connectable to other components. The negative electrode terminal tab 143c is disposed on the outer layer side of the electrode body 140 when the electrode body 140 is wound.

[0159] The separator 141 shown in FIG. 25 is formed of, for example, a resin microporous film such as polyolefin, a nonwoven fabric made of glass or resin, a laminate of fibers such as cellulose fibers, etc., and is capable of allowing lithium ions to pass through ion permeation holes (not shown). Further, as the separator 141, for example, a porous body capable of holding an electrolytic solution in pores, a resin layer having lithium ion conductivity, etc. can be adopted.

[0160] The separator 141 is disposed throughout the layer between the positive electrode 142 and the negative electrode 143 and insulates between the positive electrode 142 and the negative electrode 143. Therefore, the separator 141 is disposed so as to be interposed between the positive electrode 142 and the negative electrode 143 at least throughout the region where the positive electrode 142 and the negative electrode 143 face each other.

[0161] As shown in FIG. 23, the electrode body 140 configured as described above is wound around the support portion 114, so that it is combined integrally with the support portion 114 and wound in such a manner that the positive electrode 142 and the negative electrode 143 are laminated radially multiple times with the separator 141 interposed therebetween around the central axis C of the support portion 114, thereby becoming a wound electrode.

[0162] Note that, in the electrode body 140 housed together with the support portion 114 in the housing space 115 of the exterior body 112, one of the positive electrode 142 and the negative electrode 143 is electrically connected (conductive) to the current collector plate 151, and the other electrode is electrically connected (conductive) to the container body 120. Note that examples of the electrical connection include contact via a carbon-based material, welding of metals, or contact of metals.

[0163] In this embodiment, the negative electrode 143 is electrically connected to the current collector plate 151, and the positive electrode 142 is electrically connected to the container body 120. As a result, the current collector plate 151 can function as an external connection terminal for the negative electrode, and the container body 120 can function as an external connection terminal for the positive electrode. However, it is not limited to this case. By electrically connecting the negative electrode 143 to the container body 120, the container body 120 can function as an external connection terminal for the negative electrode, and by electrically connecting the positive electrode 142 to the current collector plate 151, the current collector plate 151 can function as an external connection terminal for the positive electrode.

[0164] When electrically connecting the negative electrode 143 to the current collector plate 151, for example, the negative terminal tab 143c may be directly electrically connected to the current collector plate 151, or the negative terminal tab 143c and the current collector plate 151 may be electrically connected via a conductor corresponding to a lead wire (not shown). Similarly, when electrically connecting the positive electrode 142 to the container body 120, for example, the positive terminal tab 142c may be directly electrically connected to the container body 120, or the positive terminal tab 142c and the container body 120 may be electrically connected via a conductor corresponding to a lead wire (not shown).

[0165] Incidentally, the secondary battery 110 of this embodiment includes a positioning portion 155 that positions the relative position at the start of winding of at least one of the positive electrode 142 and the negative electrode 143 with respect to the separator 141 shown in FIG. 25. Specifically, the positioning portion 155 includes a welding portion (fixing portion according to the present invention) 156 that fixes the support portion 114 and the separator 141. The positive electrode 142 and the negative electrode 143 are positioned with respect to the support portion 114 with the welding portion 156 as a reference, so that the relative position with respect to the separator 141 is positioned.

[0166] (Formation of electrode body) Regarding the above-described positioning, the case of forming the electrode body 140 using the support portion 114 as a winding core will be described below. First, as shown in FIG. 25, after preparing a separator 141, a positive electrode 142, and a negative electrode 143 respectively, the separator 141 is welded to the outer peripheral surface of the support column portion 114. Thereby, the welded portion 156 formed by welding the outer peripheral surface of the support column portion 114 and the separator 141 to each other can be used as the positioning portion 155, and the separator 141 can be positioned with respect to the support column portion 114.

[0167] In addition, when the length of the separator 141 is determined in advance, a portion shifted toward the region R1 where the positive electrode 142 is overlapped from the central portion in the length direction of the separator 141 is welded to the outer peripheral surface of the support column portion 114. Thereby, a larger region R2 where the negative electrode 143 is overlapped can be ensured than the region R1 where the positive electrode 142 is overlapped in the separator 141.

[0168] Next, as shown by the arrow M in FIG. 25, the support column portion 114 is rotated around the central axis C. At this time, the support column portion 114 is rotated so that the region R2 where the negative electrode 143 is overlapped in the separator 141 is wound around the support column portion 114 first. Next, as shown in FIG. 26, the separator 141 and the negative electrode 143 are overlapped so that the negative electrode 143 is inserted between the separator 141 wound around the support column portion 114 and the support column portion 114 in advance. At this time, the negative electrode 143 is inserted until it abuts against the welded portion 156 as shown by the arrow S in FIG. 26. Thereby, the negative electrode 143 can be positioned with respect to the support column portion 114 with reference to the welded portion 156. Next, in this state, as shown in FIG. 27, the support column portion 114 is further rotated. Thereby, the negative electrode 143 can be wound around the support column portion 114 first, and the innermost layer of the electrode body 140 can be formed by the negative electrode 143.

[0169] Furthermore, after inserting the negative electrode 143 as described above, the positive electrode 142 is also superposed on the separator 141 so as to abut against the welded portion 156. Thereby, the positive electrode 142 can be positioned on the support column portion 114 with reference to the welded portion 156. Thereafter, the support column portion 114 is continuously rotated and wound so as to wind the separator 141, the positive electrode 142, and the negative electrode 143. Thereby, winding can be performed while positioning the relative positions of the positive electrode 142 and the negative electrode 143 with respect to the separator 141. As a result, as shown in FIG. 23, it is possible to produce the electrode body 140 wound around the support column portion 114. In addition, due to the relationship of winding the negative electrode 143 around the support column portion 114 prior to the positive electrode 142, it is preferable to form the negative electrode 143 to be longer than the positive electrode 142.

[0170] (Operation of the secondary battery) According to the secondary battery 110 of the present embodiment configured as described above, as shown in FIGS. 22 to 24, the current collector plate 151 that functions as an external connection terminal for the negative electrode is exposed to the outside, and the container body 120 that functions as an external connection terminal for the positive electrode is exposed to the outside. Therefore, it is possible to use the secondary battery 110 by utilizing these current collector plate 151 and container body 120.

[0171] In particular, according to the secondary battery 110 of the present embodiment, in addition to the electrode body 140, the support column portion 114 is accommodated in the accommodation space 115. The support column portion 114 is arranged such that the upper end portion contacts the current collector plate 151 from below through the through hole 133, and the lower end portion contacts the bottom wall portion 121 of the container body 120 from above. Thereby, the current collector plate 151 can be supported from below by utilizing the support column portion 114. Moreover, since the current collector plate 151 is welded to the lid member 130 via the sealant film 150, it is integrally combined with the lid member 130. Therefore, the support column portion 114 can support the lid member 130 from below via the current collector plate 151.

[0172] Therefore, even if the entire exterior body 112 including the lid member 130 is formed to be thin, for example, unintended deformation such as the lid member 130 being bent can be suppressed at a stage prior to the welding joint between the container body 120 and the lid member 130. Therefore, the welding operation can be performed while suppressing displacement of the lid member 130 relative to the container body 120, improving the working efficiency and leading to an improvement in productivity. Furthermore, the container body 120 and the lid member 130 can be accurately and appropriately welded, and reliable sealing performance can be obtained. Therefore, a secondary battery 110 with high operating reliability and high quality can be achieved.

[0173] Furthermore, the electrode body 140 is wound around the support column portion 114, so that it becomes a wound electrode wound around the central axis C of the support column portion 114 with the positive electrode 142 and the negative electrode 143 being overlapped with each other with the separator 141 interposed therebetween. That is, since the winding core when winding the electrode body 140 is used as the support column portion 114, after forming the electrode body 140 by winding, the electrode body 140 together with the support column portion 114 can be accommodated in the container body 120. Therefore, the assembly work can be efficiently performed, and in this regard, it can also lead to an improvement in productivity.

[0174] Furthermore, when winding the electrode body 140 using the support column portion 114, the support column portion 114 and the separator 141 can be fixed using the welded portion 156, positioning the separator 141 with respect to the support column portion 114, and positioning the positive electrode 142 and the negative electrode 143 with respect to the support column portion 114 via the welded portion 156. Therefore, it is possible to suppress the occurrence of so-called winding deviation in which the relative positional relationship between the positive electrode 142 and the negative electrode 143 is displaced with the separator 141 interposed therebetween. As a result, the positive electrode 142 and the negative electrode 143 can be made into an electrode body 140 that is accurately overlapped with each other with the separator 141 interposed therebetween, and a secondary battery 110 with improved operating reliability can be achieved.

[0175] As described above, according to the secondary battery 110 of the present embodiment, it is possible to wind the positive electrode 142 and the negative electrode 143 while maintaining an appropriate relative positional relationship with the separator 141 interposed therebetween, and a battery of a metal case type including an electrode body 140 with improved operating reliability can be obtained. Furthermore, even if the exterior body 112 is made thin, reliable sealing performance can be obtained and productivity can be improved. Further, since the current collector plate 151 is disposed on the upper surface side of the lid member 130, the current collector plate 151 can be largely exposed over the entire surface. Therefore, the current collector plate 151 can be easily and effectively used as an external connection terminal for the negative electrode, and the secondary battery 110 having excellent usability and mountability can be obtained.

[0176] Furthermore, in the secondary battery 110 of the present embodiment, when the container body 120 and the lid member 130 are formed of the clad material or the like described above, or when the container body 120 and the lid member 130 are subjected to plating treatment or the like, for example, when the internal pressure increases due to heat generation of the secondary battery 110 or the like due to some factor, it is also possible to take a fail-safe measure of peeling the metal interface and releasing the internal pressure to the outside.

[0177] (Modification of the Second Embodiment) In the second embodiment, when winding the electrode body 140 around the support column portion 114, as shown in FIG. 25, the separator 141 is welded to the outer peripheral surface of the support column portion 114 to form a welded portion 156, thereby preventing displacement of the separator 141 with respect to the support column portion 114. However, the present invention is not limited to the welded portion 156. For example, an adhesive portion may be formed by adhesively fixing the separator 141 to the outer peripheral surface of the support column portion 114 using an adhesive, thereby preventing displacement of the separator 141 with respect to the support column portion 114. In this case, the adhesive portion functions as a fixing portion in the present invention.

[0178] (Third Embodiment) Next, a third embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this third embodiment, the same components as those in the second embodiment are denoted by the same reference numerals and their description will be omitted.

[0179] As shown in FIG. 28, in the secondary battery (electrochemical cell according to the present invention) 160 of this embodiment, the support column portion 114 is made of a conductor. Specifically, the support column portion 114 is formed in a cylindrical shape made of metal. The material of the support column portion 114 is not particularly limited, but for example, nickel or the like can be preferably used in the same manner as the current collector plate 151.

[0180] The electrode body 140 is electrically connected to the current collector plate 151 through the support column portion 114 in relation to the support column portion 114 being a conductor. Specifically, the electrode body 140 is wound around the support column portion 114 with the negative electrode 143 being electrically connected to the support column portion 114. Thereby, the negative electrode 143 is electrically connected to the current collector plate 151 through the support column portion 114.

[0181] Furthermore, in relation to the support column portion 114 being a conductor, an insulator 161 that insulates between the support column portion 114 and the bottom wall portion 121 is formed between the lower end portion of the support column portion 114 and the bottom wall portion 121 of the container body 120. In the illustrated example, the insulator 161 is formed over the entire upper surface of the bottom wall portion 121 in the container body 120. Thereby, it is possible to electrically insulate between the lower end portion of the support column portion 114 and the bottom wall portion 121 by using the insulator 161.

[0182] Note that the insulator 161 does not necessarily need to be formed over the entire upper surface of the bottom wall portion 121, and for example, it may be formed at least in the region where the lower end portion of the support column portion 114 contacts the upper surface of the bottom wall portion 121. Furthermore, the insulator 161 may be continuously formed not only on the upper surface of the bottom wall portion 121 but also on the inner surface side of the peripheral wall portion 122. Furthermore, the insulator 161 does not necessarily have to be formed on the bottom wall portion 121 side, and it may be formed on the lower end surface of the support portion 114. Furthermore, the insulator 161 may be formed on each of the upper surface of the bottom wall portion 121 and the lower end surface of the support portion 114.

[0183] The insulator 161 is not limited to a specific one. For example, an insulating synthetic resin film may be employed. Furthermore, an insulating tape made of a synthetic resin with excellent insulation properties (for example, a tape made of polyimide, a tape made of polyphenylene sulfide (PPS), or a tape made of polyethylene terephthalate (PET)) may be adopted as the insulator 161. Furthermore, an insulating film using an insulating paint may be adopted as the insulator 161.

[0184] Regarding the electrical connection between the support portion 114 and the negative electrode 143, it is not limited to a specific method. For example, as shown in FIGS. 29 and 30, the separator 141 is fixed using the welded portion 156, and while suppressing the displacement of the separator 141 with respect to the support portion 114, the negative electrode terminal tab 143c of the negative electrode 143 may be joined to the outer peripheral surface of the support portion 114 via a joining portion 157 by welding or the like. At this time, by forming the joining portion 157 with reference to the position of the welded portion 156, the relative position of the negative electrode 143 with respect to the separator 141 can be positioned.

[0185] Therefore, by rotating the support portion 114, the separator 141 and the negative electrode 143 can be wound in a state where displacement is suppressed. Furthermore, after the separator 141 and the negative electrode 143 are wound around the support portion 114 in advance, the positive electrode 142 is wound together. Thereby, the separator 141, the negative electrode 143, and the positive electrode 142 can be wound in a state where displacement is suppressed, and the electrode body 140 wound around the support portion 114 can be formed.

[0186] Regarding the positive electrode 142, similar to the second embodiment, the positive electrode terminal tab 142c may be directly electrically connected to the container body 120, or the positive electrode terminal tab 142c and the container body 120 may be electrically connected via a conductor (equivalent to a lead wire) not shown.

[0187] (Operation of the secondary battery) Even in the secondary battery 160 of this embodiment configured as described above, the same operational effects as those of the second embodiment can be achieved. In addition, regarding the negative electrode 143, since it can be electrically connected to the current collector plate 151 through the support portion 114, conductors (equivalent to lead wires) etc. become unnecessary, and it is easy to reduce the electrical resistance. Therefore, it is easy to improve the battery performance. Further, regarding the negative electrode 143, since electrical connection can be made by bringing the support portion 114 into contact with the current collector plate 151, the assembly work can be carried out more efficiently.

[0188] (Modification of the third embodiment) In the third embodiment, the negative electrode terminal tab 143c is joined to the outer peripheral surface of the support portion 114 by the joining portion 157, but it is not limited to this case. For example, as shown in FIGS. 31 and 32, a slit groove 158 may be formed in the support portion 114, and the negative electrode 143 may be positioned with respect to the support portion 114 by inserting the negative electrode terminal tab 143c into the slit groove 158. Note that the slit groove 158 is formed in a vertically long slit shape along the axial direction of the support portion 114 and is formed so as to penetrate the support portion 114 in the radial direction.

[0189] (Modification of the third embodiment) In the third embodiment, the support portion 114 itself is formed of a metal material to function as a conductor, but it is not limited to this case. For example, the support portion 114 may be formed of a synthetic resin having conductivity (conductive resin). As such a synthetic resin, from the viewpoint of considering mechanical strength and heat resistance, it is preferable to use engineering plastics. For example, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyether ether ketone (PEEK), perfluoroalkoxy fluororesin (PFA), etc. can be used.

[0190] Furthermore, after forming the material of the support portion 114 with an insulating synthetic resin, the support portion 114 may be formed by forming a metal film on the outer surface of the material. Even in this case, since electrical connection can be achieved using the metal film, the support portion 114 can function as a conductor. When forming the metal film, for example, plating treatment can be performed by applying metal spraying treatment or the like.

[0191] (Modification of the Third Embodiment) Furthermore, in the above-described third embodiment, the negative electrode 143 of the electrode body 140 is electrically connected to the current collector plate 151 through the support portion 114. However, for example, as shown in FIG. 33, a secondary battery (electrochemical cell according to the present invention) 170 in which the electrode body 140 is electrically connected to the container body 120 through the support portion 114 may be used.

[0192] In this case, an insulator 171 that insulates between the support portion 114 and the current collector plate 151 is formed between the upper end portion of the support portion 114 and the current collector plate 151. The insulator 171 may be formed in a region of the lower surface of the current collector plate 151 where the upper end portion of the support portion 114 contacts. Thereby, it is possible to electrically insulate between the support portion 114 and the current collector plate 151 using the insulator 171. Note that the insulator 171 may be formed on the upper end surface of the support portion 114, or may be formed on each of the lower surface of the current collector plate 151 and the upper end surface of the support portion 114.

[0193] Regarding the positive electrode 142, the positive electrode terminal tab 142c may be directly electrically connected to the current collector plate 151, or the positive electrode terminal tab 142c and the current collector plate 151 may be electrically connected via a conductor (corresponding to a lead wire) not shown.

[0194] In the case of the secondary battery 170 configured as described above, the current collector plate 151 can function as an external connection terminal for the positive electrode, and the container body 120 can function as an external connection terminal for the negative electrode. Therefore, the secondary battery 170 can be used by utilizing the container body 120 and the current collector plate 151.

[0195] When winding the electrode body 140 around the support column portion 114, it is not necessary to conduct the negative electrode 143 with respect to the support column portion 114, and the positive electrode 142 may be conducted. In this case, the positive electrode 142 and the container body 120 can be electrically connected through the support column portion 114. Regarding the negative electrode 143, the negative electrode terminal tab 143c may be directly electrically connected to the current collector plate 151, or the negative electrode terminal tab 143c and the current collector plate 151 may be electrically connected via a conductor (corresponding to a lead wire) not shown. Thereby, the current collector plate 151 can function as an external connection terminal for the negative electrode, and the container body 120 can function as an external connection terminal for the positive electrode.

[0196] (Fourth Embodiment) Next, a fourth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this fourth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals and their descriptions are omitted. In the second and third embodiments, the current collector plate 151 is welded to the lid member 130 via the sealant film 150, and then the upper end portion of the support column portion 114 is brought into contact with the current collector plate 151, and the lower end portion of the support column portion 114 is brought into contact with the bottom wall portion 121 of the container body 120, and the support column portion 114 is disposed in the accommodation space 115. In contrast, in this embodiment, the current collector plate 151 is welded to the bottom wall portion 121 of the container body 120 via the sealant film 150.

[0197] As shown in FIG. 34, in the secondary battery (electrochemical cell according to the present invention) 180 of the present embodiment, a through hole 181 penetrating the bottom wall portion 121 of the container body 120 in the vertical direction is formed coaxially with the battery axis O1 at the center of the bottom wall portion 121. The shape of the through hole 181 is not particularly limited, but for example, it is formed in a circular shape in plan view.

[0198] And a current collector plate 151 is thermally welded to the bottom wall portion 121 in which the through hole 181 is formed via a sealant film 150. Specifically, the current collector plate 151 is thermally welded to the lower surface of the bottom wall portion 121 via the sealant film 150 and is exposed downward over the entire surface. The sealant film 150 is formed in an annular shape surrounding the through hole 181 formed in the bottom wall portion 121 and is arranged so as to overlap the lower surface of the bottom wall portion 121 in a state of being coaxially arranged with the battery axis O1. In the illustrated example, the inner peripheral edge portion 150a of the sealant film 150 is folded upward to protect the inner peripheral surface of the through hole 181 formed in the bottom wall portion 121 over the entire circumference.

[0199] The current collector plate 151 is formed in a circular shape in plan view with a diameter smaller than the outer diameter of the sealant film 150 and is arranged so as to overlap the lower surface of the sealant film 150 in a state of being coaxially arranged with the battery axis O1. Thereby, the current collector plate 151 closes the through hole 181 from below.

[0200] The lid member 185 of the present embodiment is formed in a flat plate shape that overlaps the peripheral wall portion 122 of the container body 120 from above. Thereby, the lid member 185 is welded and joined in a state of overlapping the upper end opening end of the peripheral wall portion 122 over the entire circumference from above. In the illustrated example, a step 185a is provided at a position where the outer peripheral edge portion of the lid member 185 overlaps the upper end opening end of the peripheral wall portion 122. Thereby, the accommodation space 115 is sealed with high airtightness by using the step 185a.

[0201] The support column portion 114 is housed in the accommodation space 115 in the exterior body 112 together with the power generation element 113. The support column portion 114 is formed in a shaft shape extending in the vertical direction along the battery axis O1 and is arranged coaxially with the battery axis O1. In the illustrated example, the support column portion 114 is formed in a hollow cylindrical shape, and its outer diameter is smaller than the diameter of the through hole 181 and the inner diameter of the sealant film 150. As a result, the support column portion 114 is arranged such that the lower end portion (the first end portion according to the present invention) contacts the current collecting plate 151 from above through the through hole 181, and the upper end portion (the second end portion according to the present invention) contacts the lid member 185 from below. Therefore, the support column portion 114 supports the lid member 185 from below while being supported by the current collecting plate 151 integrally combined with the bottom wall portion 121 of the container body 120.

[0202] (Function of the secondary battery) Even in the secondary battery 180 of the present embodiment configured as described above, since the lid member 185 can be supported from below using the support column portion 114, even if the entire exterior body 112 including the lid member 185 is formed, for example, with a thin wall, unintended deformation such as the lid member 185 being deflected can be suppressed at the stage before the welding joint between the container body 120 and the lid member 185. Therefore, the welding operation can be performed while suppressing displacement and the like of the lid member 185 with respect to the container body 120, improving the working efficiency and leading to an improvement in productivity. Furthermore, reliable sealing performance can be obtained, and a secondary battery 180 with high operating reliability and high quality can be achieved.

[0203] The embodiments of the present invention have been described above, but these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and their modifications include, for example, those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the equivalent range.

[0204] For example, in each of the above embodiments, a secondary battery has been described as an example of an electrochemical cell. However, the present invention is not limited to this case, and the present invention can also be applied to other electrochemical cells using an electrode capable of occluding lithium ions. Specifically, for example, the present invention may be applied to various power storage devices such as electric double layer capacitors and lithium ion capacitors.

[0205] When applying the electrochemical cell to an electric double layer capacitor, the positive electrode and the negative electrode may be used as a pair of polarized electrodes. Examples of the polarized electrode in this case include those obtained by mixing powdered activated carbon obtained by an activation treatment with a conductive assistant and a binder, and rolling or press-molding them. Examples of the electrolytic solution include those obtained by dissolving a supporting salt such as a quaternary ammonium salt in a non-aqueous solvent. When applying the electrochemical cell to a lithium ion capacitor, only one of the positive electrode and the negative electrode may be the above-described polarized electrode, and an electrode for a lithium ion battery may be used for the other electrode. As the electrolytic solution, the same one as that for a lithium ion battery can be used.

[0206] Furthermore, in the first embodiment above, lithium ions have been described as an example of the ions that move between the positive electrode body and the negative electrode body through the separator during charge and discharge. However, the present invention is not limited to this case, and for example, ions of metals having a low potential such as sodium ions, potassium ions, and magnesium ions may be used.

[0207] Furthermore, in the second and third embodiments above, the current collector plate is arranged on the upper surface side of the top wall portion of the lid member. However, the present invention is not limited to this case, and the current collector plate may be arranged on the lower surface side of the lid member. In this case, since the current collector plate can be arranged on the lower surface side of the lid member, the entire current collector plate and the lid member can be supported from below using the support portion. Therefore, unintended deflection of the lid member can be effectively suppressed.

[0208] Furthermore, in the above-described second and third embodiments, the case where a cylindrical support column portion is used has been described as an example. However, the shape of the support column portion is not limited to a cylindrical shape and may be changed as appropriate. As the support column portion, it can be used as a winding core when winding the electrode body, and when it is set in the accommodation space together with the electrode body, if the upper end portion contacts the current collector plate and the lower end portion contacts the bottom wall portion so that the lid member can be supported from below, the outer shape can be arbitrarily changed.

[0209] Furthermore, in the case of a hollow support column portion, as the inner shape, for example, a square shape, a polygonal shape, a star shape, a cross shape, a slit shape, etc. may be adopted in a plan view seen from the central axis direction. In particular, when such an inner shape is adopted, it is preferable because it becomes easier to apply a rotational torque to the support column portion.

Explanation of Reference Numerals

[0210] Z... Laminating direction 1, 90, 110, 160, 170, 180... Secondary battery (electrochemical cell) 2, 140... Electrode body 3, 112... Outer package 10, 142... Positive electrode 13... Positive electrode main body 14... Positive electrode connection piece 20, 143... Negative electrode 21... Negative electrode current collector 23... Negative electrode main body 23A... Inner peripheral side negative electrode main body (first negative electrode main body) 24... Negative electrode connection piece 30, 141... Separator 41, 51... Metal layer 42, 52... Inner resin layer (resin layer) 43, 53... Outer resin layer (resin layer) 80... Adhesive layer (adhesive member, negative electrode positioning portion) 85... Welded portion (negative electrode positioning portion) 86... Separator welded portion (negative electrode positioning portion) 88... Empty winding portion (negative electrode positioning portion) 87... Positive electrode side welded portion (positive electrode positioning portion) Positioning parts at 100, 155, etc. Support parts at 114, etc. Accommodation space at 115 Container body at 120 Bottom wall part at 121 Peripheral wall part at 122 Lid members (sealing plates) at 130, 185, etc. Top wall part at 131 Through hole at 133 Sealing film (sealing material) at 150 Current collector plate at 151 Welding part (fixing part) at 156

Claims

1. An electrode body having a separator, a positive electrode having a positive electrode current collector, and a negative electrode having a negative electrode current collector, wherein the positive electrode and the negative electrode are overlapped with each other with the separator interposed therebetween by being wound; An exterior body that houses the electrode body therein, and At least one of the positive electrode and the negative electrode is positioned by a positioning portion such that a relative position at the start of winding with respect to the separator is positioned, The electrode body is wound flat so that the positive electrode and the negative electrode are alternately laminated with the separator interposed therebetween, The positive electrode includes a plurality of positive electrode main bodies arranged along the lamination direction of the electrode body, and a plurality of positive electrode connection pieces that connect the plurality of positive electrode main bodies to each other, The negative electrode includes a plurality of negative electrode main bodies arranged along the lamination direction of the electrode body, and a plurality of negative electrode connection pieces that connect the plurality of negative electrode main bodies to each other, The electrode body is formed so as to be wound so as to fold back the positive electrode connection piece and the negative electrode connection piece, and the positive electrode main body and the negative electrode main body are arranged in a state of facing each other alternately in the lamination direction with the separator interposed therebetween, The positioning portion includes a first negative electrode main body located on the winding start side among the plurality of negative electrode main bodies, and a negative electrode positioning portion provided between the first negative electrode main body and the separator to position the first negative electrode main body with respect to the separator, The negative electrode positioning portion is arranged so as to be located between an outer end portion of the first negative electrode main body that faces the positive electrode connection piece with the separator interposed therebetween and the separator, integrally combines the outer end portion and the separator, and covers a portion of the negative electrode current collector that is exposed to the outside at the outer end portion of the first negative electrode main body from the separator side. An electrochemical cell characterized by being arranged.

2. In the electrochemical cell according to Claim 1, The negative electrode positioning portion reduces the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end portion through the separator during charge and discharge compared to the ionic conductivity of ions moving between the positive electrode main body and the negative electrode main body through the separator. Electrochemical cell.

3. In the electrochemical cell according to Claim 2, The negative electrode positioning portion is an insulating adhesive member that adheres the outer end portion of the first negative electrode body and the separator to each other, and closes the ion permeation holes formed in the separator, in the electrochemical cell.

4. In the electrochemical cell according to claim 2, the negative electrode positioning portion is a welded portion in which the outer end portion of the first negative electrode body and the separator are welded to each other, and closes the ion permeation holes formed in the separator by the welding, in the electrochemical cell.

5. In the electrochemical cell according to any one of claims 1 to 4, the exterior body is formed of a laminate film having a metal layer and resin layers covering both surfaces of the metal layer, in the electrochemical cell.

6. An electrochemical cell manufacturing method, comprising a separator, a positive electrode having a positive electrode current collector, and a negative electrode having a negative electrode current collector, wherein the positive electrode and the negative electrode, which are superposed with each other with the separator interposed therebetween, are flatly wound to form an electrode body in which the positive electrode and the negative electrode are alternately laminated with the separator interposed therebetween, and an exterior body that houses the electrode body therein, wherein the positive electrode includes a plurality of positive electrode bodies arranged along the lamination direction of the electrode body, and a plurality of positive electrode connection pieces that connect the plurality of positive electrode bodies to each other, and the negative electrode includes a plurality of negative electrode bodies arranged along the lamination direction of the electrode body, and a plurality of negative electrode connection pieces that connect the plurality of negative electrode bodies to each other, and which comprises an electrode body forming step of forming the electrode body such that the positive electrode body and the negative electrode body are alternately opposed to each other in the lamination direction with the separator interposed therebetween by winding the positive electrode connection piece and the negative electrode connection piece in a folded manner, and a positioning step of positioning the first negative electrode body with respect to the separator by providing a negative electrode positioning portion between the first negative electrode body located on the winding start side among the plurality of negative electrode bodies and the separator during the electrode body forming step. During the electrode body forming step, a positioning step is performed to position the first negative electrode body with respect to the separator by providing a negative electrode positioning portion between the first negative electrode body located on the winding start side among the plurality of negative electrode bodies and the separator. During the positioning step, the negative electrode positioning portion is arranged so as to be located between the outer end portion of the first negative electrode body that faces the positive electrode connection piece with the separator interposed therebetween and the separator. The negative electrode positioning portion integrally combines the outer end portion and the separator, and the negative electrode positioning portion is provided so as to cover the portion of the negative electrode current collector that is exposed to the outside at the outer end portion of the first negative electrode body from the separator side. A method for manufacturing an electrochemical cell, characterized in that.

7. In the method for manufacturing an electrochemical cell according to claim 6, During the positioning step, the surface of the separator is covered with the negative electrode positioning portion so as to block the ion permeation holes formed in the separator, and the ionic conductivity of the ions moving from the positive electrode connection piece to the outer end portion through the separator is reduced compared to the ionic conductivity of the ions moving between the positive electrode body and the negative electrode body through the separator. A method for manufacturing an electrochemical cell.

8. In the method for manufacturing an electrochemical cell according to claim 6 or 7, As the negative electrode positioning portion, an insulating adhesive member is used, During the positioning step, After applying the adhesive member on the outer end portion of the first negative electrode body or on the surface of the separator facing the outer end portion of the first negative electrode body, at least a part of the applied adhesive member is solidified or made in a wet state, and then the outer end portion of the first negative electrode body and the separator are adhered to each other to perform positioning. A method for manufacturing an electrochemical cell.

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