JP2020080283A - Electrochemical cell - Google Patents

Abstract

To provide an electrochemical cell in which the degree-of-freedom of the shape is improved, while securing the capacity.SOLUTION: A cell includes a negative electrode body 30 and a positive electrode body 40 wound flatly while superposed each other. The negative electrode body 30 has multiple negative electrode bodies 31, and at least one negative electrode connection part 32. The positive electrode body 40 has multiple positive electrode bodies 41, and at least one positive electrode connection part 42. The at least one negative electrode connection part 32 has a pair of outer edges 35 directing in the negative electrode width direction. The at least one positive electrode connection part 42 has a pair of outer edges 45 directing in the positive electrode width direction. The pair of outer edges 35 of the negative electrode connection part 32 are recessed so that they approach each other at the intermediate part in the negative electrode coupling direction. The pair of outer edges 45 of the positive electrode connection part 42 are recessed so that they approach each other at the intermediate part in the positive electrode coupling direction, and facing the principal surface of the negative electrode body 30.SELECTED DRAWING: Figure 7

Description

  The present invention relates to electrochemical cells.

BACKGROUND ART Conventionally, electrochemical cells such as lithium-ion secondary batteries and electrochemical capacitors have been widely used as power sources for small devices such as smartphones, wearable devices, and hearing aids.
In such an electrochemical cell, it is necessary to increase the area of electrodes facing each other in the electrochemical cell from the viewpoint of increasing the battery capacity and the charging current and discharging current. As a structure of an electrochemical cell, a structure is known in which a pair of strip-shaped electrodes are opposed to each other via a strip-shaped separator and housed in a case, and the electrodes and the separator are impregnated with an electrolytic solution. For example, a structure in which a strip-shaped electrode and a strip-shaped separator are wound and housed in a cylindrical or coin-shaped case, or a structure in which a strip-shaped electrode is deformed into a flat shape and then housed in a laminate film is known.

  Further, in Patent Document 1 below, a positive electrode plate and a negative electrode plate are each formed in a band shape in which a plurality of laminated surfaces are connected by connecting pieces, and the laminated surface of the positive electrode plate and the laminated surface of the negative electrode plate are alternately interposed via a separator. Disclosed is a battery in which a positive electrode plate and a negative electrode plate are bent with a connecting piece so as to be stacked and wound in a flat shape to form an electrode plate group.

International Publication No. 02/13305

  However, in the above conventional technique, when the strip-shaped electrode is wound and then deformed into a flat shape, the shape after the deformation is limited to a relatively simple shape such as a rectangular parallelepiped shape. Therefore, it is difficult to arrange the electrodes at a high density on the exterior body formed in a desired shape. When the connecting piece is bent and wound into a flat shape, the connecting piece is arranged so as to project from the stacking surface when viewed from the stacking direction of the stacking surface. Therefore, the outer shape of the electrode becomes complicated, and a gap is likely to be formed around the electrode in the outer package.

  For example, in the technique described in Patent Document 1, since the connecting piece extends with a substantially constant width, when the connecting piece is bent and wound, the connecting piece is angular when viewed from the stacking direction of the stacking surface. Stick out from. Therefore, a gap is likely to be formed around the corner portion of the connecting piece in the exterior body. If the connecting piece is formed with a narrow width in order to reduce the corner portion of the connecting piece, the capacitance may decrease as the electrode area decreases.

  Therefore, it is difficult to arrange the electrodes wound in a flat shape on the outer casing formed in a desired shape with high density. Therefore, in the electrochemical cell of the prior art, there is room for improvement in that the degree of freedom of the shape is improved and the capacity is secured at the same time.

  Therefore, the present invention provides an electrochemical cell in which the degree of freedom in shape is improved and the capacity is secured.

  The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first state in a developed state and a developed state. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body.

According to the present invention, the negative electrode active material is arranged on the surface of the negative electrode connecting portion, and the positive electrode active material is arranged on the positive electrode connecting portion facing the negative electrode connecting portion. Discharge (charge/discharge in the case of a secondary battery) can also be performed at the negative electrode connection portion and the positive electrode connection portion. Therefore, the capacity of the electrochemical cell can be improved as compared with the case where the active material is not arranged on the surfaces of the negative electrode connecting portion and the positive electrode connecting portion.
Here, pay attention to a pair of negative electrode main bodies that are adjacent to each other in a developed state, and a negative electrode connecting portion that connects the pair of negative electrode main bodies. The negative electrode connecting portion is bent so that the pair of negative electrode bodies are overlapped with each other. Therefore, the negative electrode connecting portion is provided so as to project from the negative electrode body when viewed from the direction in which the plurality of negative electrode bodies overlap (hereinafter referred to as the stacking direction). Since the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other at the intermediate portion in the first direction, the negative electrode connecting portion projects while narrowing in width as it is farther from the negative electrode body when viewed from the stacking direction. Therefore, as compared with the configuration in which the negative electrode connecting portion extends with a constant width, the negative electrode body can be wound into a shape with less unevenness when viewed in the stacking direction.
Moreover, the pair of outer edges of the positive electrode connecting portion are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body. Thereby, the pair of outer edges of the positive electrode connecting portion can be arranged along the outer edge of the negative electrode connecting portion. Therefore, as compared with the case where the positive electrode connecting portion extends with a constant width, the area of the positive electrode connecting portion can be increased, so that the capacity of the electrochemical cell can be improved. Further, since the pair of outer edges of the positive electrode connecting portion face the main surface of the negative electrode body, it is possible to prevent the positive electrode connecting portion from protruding from the negative electrode body.
Therefore, the negative electrode body and the positive electrode body can be wound into a desired flat shape with less unevenness, and the negative electrode body and the positive electrode body can be arranged in the outer package without a gap.
As described above, it is possible to provide an electrochemical cell in which the degree of freedom in shape is improved and the capacity is ensured.

  In the above-mentioned electrochemical cell, it is desirable that the pair of outer edges of the positive electrode connecting portion are connected to outer edges of the positive electrode body that are oriented in a direction orthogonal to the second direction via inflection points.

  According to the present invention, the pair of outer edges of the positive electrode connecting portion are smoothly connected to the outer edges of the positive electrode body which face the direction orthogonal to the second direction. Thereby, it is possible to prevent the stress concentration from occurring at the connecting portion between the outer edge of the positive electrode connecting portion and the outer edge of the positive electrode body, and the positive electrode body from being broken or otherwise damaged. Therefore, the strength of the positive electrode body can be improved.

  In the above electrochemical cell, it is preferable that the pair of outer edges of the positive electrode connecting portion extend in an arc shape tangent to the outer edges of the positive electrode body which are orthogonal to the second direction.

  According to the present invention, the pair of outer edges of the positive electrode connecting portion are smoothly connected to the outer edges of the positive electrode body which face the direction orthogonal to the second direction. Thereby, it is possible to prevent the stress concentration from occurring at the connecting portion between the outer edge of the positive electrode connecting portion and the outer edge of the positive electrode body, and the positive electrode body from being broken or otherwise damaged. Therefore, the strength of the positive electrode body can be improved.

  In the above-mentioned electrochemical cell, it is desirable that the pair of outer edges of the negative electrode connecting portion are connected to outer edges of the negative electrode body that face a direction orthogonal to the first direction via an inflection point.

  According to the present invention, the pair of outer edges of the negative electrode connecting portion are smoothly connected to the outer edges of the negative electrode body which face the direction orthogonal to the first direction. Thereby, it is possible to prevent the concentration of stress from occurring at the connecting portion between the outer edge of the negative electrode connecting portion and the outer edge of the negative electrode main body, and damage such as breakage of the negative electrode body. Therefore, the strength of the negative electrode body can be improved.

  In the above electrochemical cell, it is preferable that the pair of outer edges of the negative electrode connecting portion extend in an arc shape tangent to an outer edge of the negative electrode body that is oriented in a direction orthogonal to the first direction.

  According to the present invention, the pair of outer edges of the negative electrode connecting portion are smoothly connected to the outer edges of the negative electrode body which face the direction orthogonal to the first direction. Thereby, it is possible to prevent the stress concentration from occurring at the connecting portion between the outer edge of the negative electrode connecting portion and the outer edge of the negative electrode main body, resulting in damage such as breakage of the negative electrode body. Therefore, the strength of the negative electrode body can be improved.

  In the above electrochemical cell, the at least one negative electrode connecting portion has an inner end side negative electrode connecting portion arranged at the innermost periphery, and the at least one positive electrode connecting portion is an outer end arranged at the outermost periphery. A side positive electrode connecting portion, and a minimum distance between the pair of outer edges in each of the at least one negative electrode connecting portion becomes smaller with increasing distance from the inner end side negative electrode connecting portion, and the pair in each of the at least one positive electrode connecting portion. It is desirable that the minimum distance between the outer edges becomes larger with increasing distance from the outer end side positive electrode connecting portion.

According to the present invention, the minimum distance between the pair of outer edges is smaller in the negative electrode connecting portion arranged on the outer layer side. Therefore, when focusing on the pair of negative electrode connecting portions adjacent to each other in the wound state, the width of the tip portion of the negative electrode connecting portion on the outer layer side is larger than the width of the tip portion of the negative electrode connecting portion on the inner layer side when viewed from the stacking direction. Narrows. As a result, the plurality of negative electrode connecting portions are arranged so as to gradually narrow in width with increasing distance from the negative electrode body when viewed in the stacking direction. Therefore, the negative electrode body can be wound into a shape having less unevenness when viewed from the stacking direction.
In addition, the minimum distance between the pair of outer edges becomes larger as the positive electrode connecting portion is arranged closer to the inner layer. Accordingly, the area of the positive electrode connecting portion arranged on the inner layer side can be increased in accordance with the change in the minimum distance between the pair of outer edges of the negative electrode connecting portion. Therefore, the area of the positive electrode body can be increased and the capacity of the electrochemical cell can be improved as compared with the case where the minimum distance between the pair of outer edges of the plurality of positive electrode connecting portions is equal to each other.

  In the above electrochemical cell, the plurality of negative electrode main bodies have an outer end side negative electrode main body arranged at an outermost periphery and an inner end side negative electrode main body arranged at an innermost periphery, and the at least one negative electrode connecting portion. Includes an inner end side negative electrode connecting portion connected to the inner end side negative electrode body, and a dimension of each of the plurality of negative electrode bodies in the first direction decreases as the distance from the outer end side negative electrode body decreases, and the at least 1 It is desirable that the dimension of each of the two negative electrode connecting portions in the first direction increases as the distance from the inner end side negative electrode connecting portion increases.

Here, pay attention to a pair of negative electrode main bodies that are adjacent to each other in the expanded state. The spacing in the wound state of the pair of negative electrode main bodies is such that the number of layers of the negative electrode main body or the like arranged between the pair of negative electrode main bodies increases as the pair of negative electrode main bodies is a pair of negative electrode main bodies located on the outer peripheral side, growing. According to the present invention, the dimension of the negative electrode connecting portion in the first direction increases as the distance from the inner end side negative electrode connecting portion increases, so that the distance between the pair of negative electrode main bodies can be ensured and the pair of negative electrode main bodies in the wound state can be separated from each other. Can be suppressed. Therefore, the displacement of the plurality of negative electrode bodies is suppressed when viewed from the stacking direction.
Moreover, according to the present invention, the negative electrode body on the outer peripheral side of the pair of negative electrode bodies is formed to be larger in the first direction than the negative electrode body on the inner peripheral side. Therefore, in the state where the plurality of negative electrode bodies are overlapped with each other, the non-overlap region in which the negative electrode body on the outer peripheral side does not overlap is provided in the negative electrode body on the outer peripheral side when viewed from the stacking direction. By arranging the negative electrode connecting portion connected to the negative electrode main body on the inner peripheral side and extending in the stacking direction in the non-overlapping region of the negative electrode main body on the outer peripheral side when viewed from the stacking direction, the negative electrode connecting portion is located on the outer peripheral side when viewed from the stacking direction. Can be suppressed from protruding from the negative electrode body.
As described above, the displacement of the plurality of negative electrode main bodies and the protrusion of the negative electrode connecting portion from the outer end side negative electrode main body are suppressed when viewed from the stacking direction. Therefore, it is possible to provide the electrochemical cell in which the negative electrode body can be wound into a desired flat shape, the degree of freedom in shape is improved, and the capacity is secured.

  In the above electrochemical cell, it is desirable that the positive electrode active material contains a lithium compound.

  According to the present invention, the presence of the edge of the negative electrode body at the portion where the positive electrode connecting portion faces is avoided, and thus lithium ions can be absorbed by the negative electrode active material of the negative electrode body. Therefore, it is possible to suppress deposition of acicular lithium from the negative electrode body. Therefore, the reliability of the electrochemical cell can be improved.

  According to the present invention, it is possible to provide an electrochemical cell in which the degree of freedom in shape is improved and the capacity is secured.

It is a perspective view of the battery of an embodiment. It is sectional drawing of the battery of embodiment. It is sectional drawing of the laminated electrode body of embodiment. It is sectional drawing which expands and shows a part of laminated electrode body of embodiment. It is a perspective view which shows the laminated electrode body of embodiment. It is a top view which shows the negative electrode body and positive electrode body of embodiment. It is a top view showing the state where the negative electrode object and positive electrode object of an embodiment were piled up mutually. It is a figure which shows the winding method of the negative electrode body and positive electrode body of embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to configurations having the same or similar functions. In addition, redundant description of those configurations may be omitted. Further, in the following description, a lithium ion secondary battery (hereinafter, simply referred to as “battery”), which is a type of non-aqueous electrolyte secondary battery, will be described as an example of the electrochemical cell.

FIG. 1 is a perspective view of the battery of the embodiment. FIG. 2 is a cross-sectional view of the battery of the embodiment.
As shown in FIGS. 1 and 2, the battery 1 is an oval-shaped battery in plan view (rounded rectangular shape). The battery 1 includes a laminated electrode body 2, an electrolyte solution (not shown) with which the laminated electrode body 2 is impregnated, and an exterior body 3 in which the laminated electrode body 2 is housed.

  The exterior body 3 includes a housing portion 4 in which the laminated electrode body 2 is housed, and a sealing portion 5 that is bent along the outer periphery 4 a of the housing portion 4. The sealing portion 5 is bent along the outer periphery 4a of the housing portion 4 by, for example, drawing.

  In addition, the exterior body 3 includes a first container 10 and a second container 20 with the laminated electrode body 2 interposed therebetween. The first container 10 and the second container 20 are each formed of a laminated film. The laminate film is composed of a metal layer (metal foil), a fusion layer made of resin provided on the overlapping surface (inner side surface) to cover the metal foil, and a protective layer made of resin provided on the outer surface to cover the metal foil. And. The metal layer is formed using a metal material such as stainless steel or aluminum that blocks outside air and water vapor. The fusion-bonding layer on the overlapping surface is formed using a thermoplastic resin such as polyolefin such as polyethylene or polypropylene. The protective layer on the outer surface is formed using, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

  The first container 10 includes an oval first bottom wall portion 11 and a first peripheral wall portion 12 extending from the outer periphery of the first bottom wall portion 11 in a tubular shape. A first through hole 13 is formed in the first bottom wall portion 11. The first through hole 13 is formed at the center of the first bottom wall portion 11.

  A copper plate 15 is heat-sealed to the inner surface of the first bottom wall portion 11 via a first sealant ring 14. The first sealant ring 14 is a ring-shaped sealant film formed by using a thermoplastic resin such as polyolefin such as polyethylene or polypropylene.

  The inner surface of the copper plate 15 is connected to a later-described negative electrode body 30 (see FIG. 3) of the laminated electrode body 2. A nickel plate 16 is welded to the center of the outer surface of the copper plate 15. The nickel plate 16 penetrates the first through hole 13 and is exposed to the outside, and functions as a negative electrode terminal of the battery 1. If the copper plate 15 is made of nickel, the nickel plate 16 may be omitted.

  The second container 20 includes an oval second bottom wall portion 21, a second peripheral wall portion 22 extending in a tubular shape from the outer circumference of the second bottom wall portion 21, and an opening edge of the second peripheral wall portion 22 to the second peripheral wall. A bent portion 23 that is bent toward the outside of the portion 22 and extends toward the second bottom wall portion 21 side.

  The second bottom wall portion 21 is arranged on the opposite side of the first bottom wall portion 11 of the first container 10 with the laminated electrode body 2 interposed therebetween. The second bottom wall portion 21 is formed slightly smaller than the first bottom wall portion 11 of the first container 10. A second through hole 24 is formed in the second bottom wall portion 21. The second through hole 24 is formed at the center of the second bottom wall portion 21.

  An aluminum plate 26 is heat-sealed to the inner surface of the second bottom wall portion 21 via a second sealant ring 25. The second sealant ring 25, like the first sealant ring 14, is made of a thermoplastic resin.

  The inner surface of the aluminum plate 26 is connected to a positive electrode body 40 (see FIG. 3) of the laminated electrode body 2 described later. A nickel plate 27 is welded to the center of the outer surface of the aluminum plate 26. The nickel plate 27 penetrates the second through hole 24 and is exposed to the outside, and functions as a positive electrode terminal of the battery 1. Note that, for example, instead of the aluminum plate 26, a plate material made of stainless steel can be used.

  The second peripheral wall portion 22 extends from the outer periphery of the second bottom wall portion 21 toward the first bottom wall portion 11 of the first container 10. The second peripheral wall portion 22 forms the outer periphery 4 a of the accommodation portion 4. The bent portion 23 is bent in a tubular shape from the end portion of the second peripheral wall portion 22 on the first bottom wall portion 11 side to the second bottom wall portion 21 side along the second peripheral wall portion 22. The bent portion 23 is arranged outside the second peripheral wall portion 22 with a space therebetween.

  The second peripheral wall portion 22 is arranged inside the first peripheral wall portion 12 and inside the bent portion 23. Further, the bent portion 23 is arranged inside the first peripheral wall portion 12. The fusion layer of the bent portion 23 and the fusion layer of the first peripheral wall portion 12 are thermally fused.

The sealing portion 5 is formed by heat-sealing the fusion layer of the bent portion 23 and the fusion layer of the first peripheral wall portion 12. Therefore, the outer periphery of the housing portion 4 is sealed by the sealing portion 5. Thereby, the 1st container 10 and the 2nd container 20 are piled up and exterior 3 is formed. The sealing portion 5 is formed in a tubular shape outside the housing portion 4 and is bent along the outer circumference 4 a of the housing portion 4.
A sealed space is formed in the housing portion 4 by stacking the first container 10 and the second container 20 on top of each other. Specifically, the housing portion 4 is defined by the first bottom wall portion 11, the second bottom wall portion 21, and the second peripheral wall portion 22, and is formed in an elliptical shape in a plan view.

FIG. 3 is a cross-sectional view of the laminated electrode body of the embodiment. FIG. 4 is a cross-sectional view showing an enlarged part of the laminated electrode body of the embodiment.
As shown in FIGS. 3 and 4, the laminated electrode body 2 includes a sheet-shaped negative electrode body 30, a positive electrode body 40, and a separator 50. The laminated electrode body 2 is a laminated type electrode body in which the negative electrode body 30 and the positive electrode body 40 are folded so as to be laminated alternately. Specifically, the laminated electrode body 2 is formed by stacking the negative electrode body 30 and the positive electrode body 40 via the separator 50 and winding them in a flat shape. The outermost peripheral portion of the negative electrode body 30 is connected to the above-mentioned copper plate 15 directly or via a lead tab or the like. The outermost peripheral portion of the positive electrode body 40 is connected to the above-mentioned aluminum plate 26 directly or via a lead tab or the like.

  The separator 50 is arranged between the negative electrode body 30 and the positive electrode body 40, and insulates the negative electrode body 30 and the positive electrode body 40 from each other. For example, the separator 50 is wound together with the negative electrode body 30 and the positive electrode body 40 in a state where the positive electrode body 40 is arranged so as to sandwich the positive electrode body 40 from both sides in the thickness direction. Although illustration of the separator 50 is omitted in FIG. 3, the separator 50 is interposed between the negative electrode body 30 and the positive electrode body 40 at least in the entire region where the negative electrode body 30 and the positive electrode body 40 face each other. It is supposed to be located in. Hereinafter, the direction in which the negative electrode body 30 and the positive electrode body 40 are alternately stacked is referred to as a stacking direction. The winding means winding around a specific position in one direction.

  The negative electrode body 30 is a sheet-shaped member including a negative electrode current collector foil formed of a metal material and a negative electrode active material applied to the negative electrode current collector foil. The negative electrode current collector foil is formed of a metal foil such as copper or stainless steel. The negative electrode active material is, for example, silicon oxide, graphite, hard carbon, lithium titanate, LiAl, or the like.

  The positive electrode body 40 is a sheet-shaped member including a positive electrode current collector foil made of a metal material and a positive electrode active material applied to the positive electrode current collector foil. The positive electrode current collector foil is formed of, for example, a metal foil such as aluminum or stainless steel. The positive electrode active material is a composite oxide containing lithium and a transition metal, such as lithium cobalt oxide, lithium titanate, or lithium manganate.

  The separator 50 is a member having a characteristic of allowing lithium ions to pass therethrough. The separator 50 is formed of, for example, a resin porous film made of polyolefin, a glass non-woven fabric, a resin non-woven fabric, a laminated body of cellulose fibers, or the like.

FIG. 5 is a perspective view showing the laminated electrode body of the embodiment. The separator 50 is not shown in FIG. Further, since the positive electrode body 40 is formed smaller than the negative electrode body 30 as described later, it is not exposed on the surface of the laminated electrode body 2 from the viewpoint of FIG. ..
As shown in FIG. 5, the laminated electrode body 2 is formed in a shape corresponding to the shape of the sealed space in the housing portion 4 so as to be arranged at a high density in the housing portion 4 of the exterior body 3 ( See FIG. 2). That is, the laminated electrode body 2 is formed in an oval shape (a rounded rectangular shape) when viewed from the laminating direction. The shape of the laminated electrode body 2 viewed from the laminating direction is defined as a basic shape.

Here, the shape of the negative electrode body 30 in the expanded state of the laminated electrode body 2 will be described.
FIG. 6 is a plan view showing the negative electrode body and the positive electrode body of the embodiment.
As shown in FIG. 6, the negative electrode body 30 has a plurality of (seven in the illustrated example) negative electrode bodies 31 arranged side by side in a row and at least one negative electrode body 31 that connects a pair of adjacent negative electrode bodies 31 (shown in the figure). (6 in the example). The negative electrode body 31 is a portion that extends flat along the vertical surface in the stacking direction in the stacked electrode body 2 (see FIGS. 3 and 5 ). The negative electrode connecting portion 32 is a portion that is folded back at the side portion of the laminated electrode body 2 so that the plurality of negative electrode main bodies 31 overlap each other (see FIGS. 3 and 5 ).

  Hereinafter, the direction in which the plurality of negative electrode main bodies 31 are arranged is referred to as a negative electrode connecting direction (first direction), and the direction orthogonal to the negative electrode connecting direction is referred to as a negative electrode width direction. Further, in the negative electrode connecting direction, the negative electrode main body 31 side arranged on the outer peripheral side of the laminated electrode body 2 is arranged with respect to the negative electrode body 31 arranged on the most winding center side of the laminated electrode body 2 among the plurality of negative electrode main bodies 31. It is defined as "outer peripheral side", and the opposite direction is defined as "inner peripheral side". In addition, hereinafter, the plurality of negative electrode main bodies 31 will be described by sequentially ordinal numbers from the innermost peripheral negative electrode main body 31 to the outer peripheral side. In other words, N is a natural number, and the Nth negative electrode main body counting from the innermost peripheral negative electrode main body 31 to the outer peripheral side is called the Nth negative electrode main body. For example, the innermost negative electrode body 31 is the first negative electrode body. The same applies to the plurality of negative electrode connecting portions 32. The first negative electrode body is an example of the “inner end side negative electrode body”. The seventh negative electrode body is an example of the “outer end side negative electrode body”. The first negative electrode connecting portion is an example of the “inner end side negative electrode connecting portion”.

  The plurality of negative electrode bodies 31 are arranged such that the centers in the negative electrode width direction overlap with each other when viewed from the negative electrode connecting direction. The plurality of negative electrode main bodies 31 are formed in a shape in which a part of the basic shape is missing. That is, the plurality of negative electrode main bodies 31 are formed in a shape in which a part of the oval shape is missing. The plurality of negative electrode bodies 31 are arranged such that the major axis A1 is oriented in the negative electrode width direction. The outer shape of each negative electrode body 31 is formed by a pair of linear portions 33 that linearly extends in the negative electrode width direction and a pair of arc-shaped curved portions 34 (outer edges) that connect the ends of the pair of linear portions 33. Has been done. The curved portion 34 extends in a direction intersecting the negative electrode connecting direction and constitutes a part of a portion of the outer edge of the negative electrode body 30 which faces the negative electrode width direction. In the negative electrode body 31, the entire linear portion 33 in the negative electrode connecting direction is provided closer to the major axis A1 with respect to the basic shape so that the dimension in the negative electrode connecting direction is smaller than that of the basic shape. The seventh negative electrode main body 31G arranged on the outermost periphery is formed so that the entire linear portion 33 on the inner peripheral side is closer to the major axis A1 side with respect to the basic shape. The negative electrode main body 31 on the inner peripheral side of the seventh negative electrode main body 31G is formed such that the entire linear portions 33 on both the inner peripheral side and the outer peripheral side are closer to the major axis A1 side with respect to the basic shape. The dimension D1 of each of the plurality of negative electrode main bodies 31 in the negative electrode connecting direction decreases with increasing distance from the seventh negative electrode main body 31G. In other words, the plurality of negative electrode main bodies 31 are formed to be larger in the negative electrode connecting direction than the negative electrode main bodies 31 adjacent to each other on the inner peripheral side.

FIG. 7 is a plan view showing a state in which the negative electrode body and the positive electrode body of the embodiment are superimposed on each other.
As shown in FIG. 7, the plurality of negative electrode connecting portions 32 are provided between a pair of negative electrode main bodies 31 that are adjacent to each other in the negative electrode connecting direction. The pair of outer edges 35 of the negative electrode connecting portion 32 facing the negative electrode width direction are curved in the negative electrode width direction so as to approach each other at an intermediate portion in the negative electrode connecting direction. In addition, the middle part is intended to include not only the center between both ends of the object but also the inner range between both ends of the object. The pair of outer edges 35 of the negative electrode connecting portion 32 are connected to the curved portion 34 of the negative electrode body 31 via the inflection point P1. In other words, a straight line that extends in the negative electrode width direction through the inflection point P1 at the outer edge of the negative electrode body 30 facing the negative electrode width direction serves as the boundary between the negative electrode body 31 and the negative electrode connecting portion 32. The pair of outer edges 35 of the negative electrode connecting portion 32 extend in an arc shape and are tangent to the curved portion 34 of the negative electrode body 31.

  As shown in FIG. 6, the dimension D2 of the plurality of negative electrode connecting portions 32 in the negative electrode connecting direction increases with increasing distance from the first negative electrode connecting portion 32A arranged on the innermost periphery. As a result, the distance between the pair of outer edges 35 of the negative electrode connecting portion 32 in the negative electrode width direction becomes larger as the distance from the first negative electrode connecting portion 32A increases. In other words, the minimum distance between the pair of outer edges 35 of the negative electrode connecting portion 32 becomes smaller as the distance from the first negative electrode connecting portion 32A increases.

Next, the shape of the positive electrode body 40 in the expanded state of the laminated electrode body 2 will be described.
The positive electrode body 40 includes a plurality of (seven in the illustrated example) positive electrode main bodies 41 arranged side by side in a row, and at least one (six in the illustrated example) positive electrode body 41 that connects a pair of adjacent positive electrode main bodies 41. And a connecting portion 42. The positive electrode body 41 is a portion that extends flat along the vertical surface in the stacking direction in the stacked electrode body 2 (see FIG. 3 ). The positive electrode connecting portion 42 is a portion that is folded back at the side portion of the laminated electrode body 2 so that the plurality of positive electrode main bodies 41 overlap the negative electrode main body 31 (see FIG. 3 ).

  Hereinafter, a direction in which the plurality of positive electrode main bodies 41 are arranged is referred to as a positive electrode connecting direction (second direction), and a direction orthogonal to the positive electrode connecting direction is referred to as a positive electrode width direction. Further, in the positive electrode connecting direction, the positive electrode main body 41 side arranged on the outer peripheral side of the laminated electrode body 2 is referred to as the positive electrode main body 41 side of the plurality of positive electrode main bodies 41 arranged on the most winding center side of the laminated electrode body 2. The outer peripheral side is defined, and the opposite direction is defined as the inner peripheral side. Further, hereinafter, the plurality of positive electrode main bodies 41 and the plurality of positive electrode connecting portions 42 will be described with ordinal numbers as in the negative electrode body 31 and the negative electrode connecting portions 32. The sixth positive electrode connecting portion is an example of the “outer end side positive electrode connecting portion”.

  The positive electrode main bodies 41 are provided in the same number as the negative electrode main bodies 31. The plurality of positive electrode main bodies 41 are arranged such that the centers in the positive electrode width direction when viewed from the positive electrode connecting direction overlap each other. The outer shape of each positive electrode body 41 is formed by a pair of linear portions 43 extending in the positive electrode width direction and a pair of arc-shaped curved portions 44 (outer edges) connecting the ends of the pair of linear portions 43. . The curved portion 44 extends in a direction intersecting the positive electrode connecting direction and constitutes a part of a portion of the outer edge of the positive electrode body 40 that faces the positive electrode width direction. The plurality of positive electrode main bodies 41 are formed in a shape in which a straight line portion 43 in the positive electrode connecting direction is provided near the long axis A2 with respect to an oval shape having a long axis A2 oriented in the positive electrode width direction. The plurality of positive electrode main bodies 41 are formed smaller than the outer shape of the negative electrode main body 31 facing each other in the laminated electrode body 2 via the separator 50. Specifically, the dimension of the first positive electrode body 41A in the positive electrode connecting direction is formed to be smaller than the dimension of the first negative electrode body 31A in the negative electrode connecting direction by a predetermined dimension. Further, the dimension of the first positive electrode body 41A in the positive electrode width direction is formed to be smaller than the dimension of the first negative electrode body 31A in the negative electrode width direction by a predetermined dimension. The same applies to the other positive electrode main bodies 41.

  As shown in FIG. 7, the plurality of positive electrode connecting portions 42 are provided between a pair of positive electrode main bodies 41 that are adjacent to each other in the positive electrode connecting direction. The pair of outer edges 45 of the positive electrode connecting portion 42, which face the positive electrode width direction, are curved in the positive electrode width direction so as to approach each other at an intermediate portion in the positive electrode connecting direction. The pair of outer edges 45 of the positive electrode connecting portion 42 are connected to the curved portion 44 of the positive electrode main body 41 via the inflection point P2. In other words, a straight line that extends in the positive electrode width direction through the inflection point P2 at the outer edge of the positive electrode body 40 that faces the positive electrode width direction serves as the boundary between the positive electrode body 41 and the positive electrode connecting portion 42. The pair of outer edges 45 of the positive electrode connecting portion 42 extend in an arc shape and are tangent to the curved portion 44 of the positive electrode main body 41.

  As shown in FIG. 6, the dimension of the positive electrode connecting portion 42 in the positive electrode connecting direction is set based on the following conditions. In the Nth positive electrode connecting portion 42, the distance D3 between the long axes A2 of the Nth positive electrode main body 41 and the (N+1)th positive electrode main body 41 adjacent to the Nth positive electrode connecting portion 42 is the Nth negative electrode main body 31 and the (N+1)th. It is formed so as to match the distance D4 between the long axes A1 of the negative electrode body 31. For example, the distance between the long axis A2 of the first positive electrode body 41A and the long axis A2 of the second positive electrode body 41B is equal to the distance between the long axis A1 of the first negative electrode body 31A and the long axis A1 of the second negative electrode body 31B. I am doing it. The distance that the pair of outer edges 45 of the positive electrode connecting portion 42 is recessed in the positive electrode width direction increases as the distance from the first positive electrode connecting portion 42A increases. In other words, the minimum distance between the pair of outer edges 45 of the positive electrode connecting portion 42 increases with increasing distance from the sixth positive electrode connecting portion 42F.

Next, the winding structure of the negative electrode body 30 and the positive electrode body 40 will be described.
FIG. 8: is a figure which shows the winding method of the negative electrode body and positive electrode body of embodiment.
As shown in FIG. 8, first, the first negative electrode body 31A of the negative electrode body 30 and the first positive electrode body 41A of the positive electrode body 40 are overlaid on each other. At this time, in the first negative electrode main body 31A and the first positive electrode main body 41A, their long axes A1 and A2 (see FIG. 6) overlap each other, and the center point of the long axis A1 and the center point of the long axis A2 overlap. Is arranged as. In addition, the negative electrode body 30 and the positive electrode body 40 are arranged so as to extend in directions opposite to each other from the first negative electrode body 31A and the first positive electrode body 41A. Hereinafter, the portion where the first negative electrode body 31A and the first positive electrode body 41A are overlapped is referred to as a reference overlapping portion.

  Subsequently, the negative electrode body 30 and the positive electrode body 40 are wound around the reference overlapping portion so that the reference overlapping portion is the winding center. Specifically, the negative electrode body 30 and the positive electrode body 40 are wound in the following procedure. The first negative electrode connecting portion 32A of the negative electrode body 30 is folded back, and the second negative electrode body 31B is superposed on the first positive electrode body 41A on the side opposite to the first negative electrode body 31A. At this time, the first negative electrode body 31A and the second negative electrode body 31B are arranged such that their major axes A1 overlap each other when viewed in the stacking direction. Further, the first positive electrode connecting portion 42A of the positive electrode body 40 is folded back, and the second positive electrode body 41B is superposed on the first negative electrode body 31A on the side opposite to the first positive electrode body 41A. At this time, the first positive electrode main body 41A and the second positive electrode main body 41B are arranged such that their major axes A2 overlap each other when viewed in the stacking direction. After that, the negative electrode connecting portions 32 are folded back so that the negative electrode main bodies 31 overlap each other, and the positive electrode connecting portions 42 are folded back so that the positive electrode main bodies 41 overlap each other. Thereby, the laminated electrode body 2 is formed.

Next, the positional relationship between the negative electrode body 30 and the positive electrode body 40 will be described.
As shown in FIG. 3, the plurality of positive electrode connecting portions 42 face the negative electrode connecting portion 32 via the separator 50. The first positive electrode connecting portion 42A and the sixth positive electrode connecting portion 42F face one negative electrode connecting portion 32 via the separator 50. The positive electrode connecting portion 42 excluding the first positive electrode connecting portion 42A and the sixth positive electrode connecting portion 42F faces the pair of negative electrode connecting portions 32 via the separator 50. For example, the second positive electrode connecting portion 42B faces the first negative electrode connecting portion 32A and the third negative electrode connecting portion 32C.

  As shown in FIG. 7, the entire outer edge 45 of the positive electrode connecting portion 42 faces the main surface of the negative electrode body 30. The outer edge 45 of the positive electrode connecting portion 42, when viewed from the direction in which the positive electrode connecting portion 42 and the negative electrode connecting portion 32 overlap, faces the pair of curved portions 34 of the negative electrode main body 31 that face each other with the separator 50 in between and the separator 50 with each other. Is arranged inside the pair of outer edges 35 of the negative electrode connecting portion 32. The outer edge 45 of the positive electrode connecting portion 42 extends along the pair of outer edges 35 of the negative electrode connecting portion 32 that face each other via the separator 50. As a result, the positive electrode connecting portion 42 is not exposed from the negative electrode connecting portion 32 when viewed from the direction in which the positive electrode connecting portion 42 and the negative electrode connecting portion 32 overlap. When the positive electrode connecting portion 42 faces the pair of negative electrode connecting portions 32, the outer layer negative electrode connecting portion 32 of the pair of negative electrode connecting portions 32 has a pair of outer edges 35 of the inner layer negative electrode connecting portion 32. The minimum interval is narrow. Therefore, the outer edge 45 of the positive electrode connecting portion 42 may be arranged inside the pair of outer edges 35 of the negative electrode connecting portion 32 of the outer layer.

  As described above, in the battery 1 of this embodiment, the negative electrode active material is arranged on the surface of the negative electrode connecting portion 32, and the positive electrode active material is arranged on the surface of the positive electrode connecting portion 42. According to this configuration, not only the negative electrode body 31 and the positive electrode body 41 but also the negative electrode connecting portion 32 and the positive electrode connecting portion 42 can be charged and discharged. Therefore, the capacity of the battery 1 can be improved as compared with the case where the active material is not arranged on the surfaces of the negative electrode connecting portion 32 and the positive electrode connecting portion 42.

  Further, in the battery 1 of the present embodiment, the pair of outer edges 35 of the negative electrode connecting portion 32 are recessed so as to approach each other in the middle portion in the negative electrode connecting direction, and the pair of outer edges 45 of the positive electrode connecting portion 42 are in the middle portion in the positive electrode connecting direction. The recesses are arranged so as to approach each other, and face the main surface of the negative electrode body 30. Here, attention is paid to the pair of negative electrode main bodies 31 that are adjacent to each other in the expanded state and the negative electrode connecting portion 32 that connects the pair of negative electrode main bodies 31. The negative electrode connecting portion 32 is provided so as to project from the negative electrode main body 31 when viewed in the stacking direction because the pair of negative electrode main bodies 31 are bent so as to overlap each other. The pair of outer edges 35 of the negative electrode connecting portion 32 are recessed so as to approach each other at the intermediate portion in the negative electrode connecting direction, and thus the negative electrode connecting portion 32 protrudes while narrowing in width as it moves away from the negative electrode body 31 when viewed from the stacking direction. Therefore, as compared with the configuration in which the negative electrode connecting portion extends with a constant width, the negative electrode body 30 can be wound into a shape with less unevenness when viewed in the stacking direction.

Moreover, the pair of outer edges 45 of the positive electrode connecting portion 42 are recessed so as to approach each other in the intermediate portion in the positive electrode connecting direction, and face the main surface of the negative electrode body 30. Thereby, the pair of outer edges 45 of the positive electrode connecting portion 42 can be arranged along the outer edge 35 of the negative electrode connecting portion 32. Therefore, the area of the positive electrode connecting portion 42 can be increased as compared with the case where the positive electrode connecting portion extends with a constant width, so that the capacity of the battery 1 can be improved. Further, since the pair of outer edges 35 of the positive electrode connecting portion 42 face the main surface of the negative electrode body 30, it is possible to prevent the positive electrode connecting portion 42 from protruding from the negative electrode body 30.
Therefore, the negative electrode body 30 and the positive electrode body 40 can be wound into a desired flat shape with less unevenness, and the negative electrode body 30 and the positive electrode body 40 can be arranged in the exterior body 3 without a gap.
As described above, it is possible to provide the battery 1 in which the degree of freedom in shape is improved and the capacity is ensured.

Further, the pair of outer edges 45 of the positive electrode connecting portion 42 are connected to the curved portion 44 of the positive electrode main body 41 that faces the positive electrode width direction via the inflection point P2.
Further, the pair of outer edges 45 of the positive electrode connecting portion 42 extend in an arc shape tangent to the curved portion 44 of the positive electrode main body 41.
According to these configurations, the pair of outer edges 45 of the positive electrode connecting portion 42 is smoothly connected to the curved portion 44 of the positive electrode main body 41. As a result, it is possible to prevent the concentration of stress from occurring at the connecting portion between the outer edge 45 of the positive electrode connecting portion 42 and the curved portion 44 of the positive electrode main body 41, and damage to the positive electrode body 40 such as breakage. Therefore, the strength of the positive electrode body 40 can be improved.

Further, the pair of outer edges 35 of the negative electrode connecting portion 32 are connected to the curved portion 34 of the negative electrode body 31 which faces the negative electrode width direction via the inflection point P1.
The pair of outer edges 35 of the negative electrode connecting portion 32 extend in an arc shape tangent to the curved portion 34 of the negative electrode body 31.
According to these configurations, the pair of outer edges 35 of the negative electrode connecting portion 32 are smoothly connected to the curved portion 34 of the negative electrode body 31. As a result, it is possible to prevent the concentration of stress from occurring at the connecting portion between the outer edge 35 of the negative electrode connecting portion 32 and the curved portion 34 of the negative electrode main body 31 and damage to the negative electrode body 30, such as breakage. Therefore, the strength of the negative electrode body 30 can be improved.

In addition, the minimum distance between the pair of outer edges 35 in each of the plurality of negative electrode connecting portions 32 becomes smaller as the distance from the first negative electrode connecting portion 32A increases. According to this configuration, the minimum distance between the pair of outer edges 35 becomes smaller as the negative electrode connecting portion 32 arranged closer to the outer layer side. Therefore, when focusing on the pair of negative electrode connecting portions 32 that are adjacent to each other in the wound state, the width of the tip portion of the negative electrode connecting portion 32 on the outer layer side is the width of the tip portion of the negative electrode connecting portion 32 on the inner layer side when viewed from the stacking direction. Narrower than width. As a result, the plurality of negative electrode connecting portions 32 are arranged so as to gradually narrow in width with increasing distance from the negative electrode body 31 when viewed in the stacking direction. Therefore, the negative electrode body 30 can be wound into a shape having less unevenness when viewed from the stacking direction.
In addition, the minimum distance between the pair of outer edges 45 in each of the plurality of positive electrode connecting portions 42 increases as the distance from the sixth positive electrode connecting portion 42F increases. According to this structure, the minimum distance between the pair of outer edges 45 increases as the positive electrode connecting portion 42 arranged on the inner layer side increases. Accordingly, the area of the positive electrode connecting portion 42 arranged on the inner layer side can be increased in accordance with the change in the minimum distance between the pair of outer edges 45 of the negative electrode connecting portion 32. Therefore, the area of the positive electrode body 40 can be increased and the capacity of the battery 1 can be improved as compared with the case where the minimum distance between the pair of outer edges of the plurality of positive electrode connecting portions is equal to each other.

In addition, the dimension of the plurality of negative electrode connecting portions 32 in the negative electrode connecting direction increases with increasing distance from the first negative electrode connecting portion 32A arranged on the innermost periphery. Here, the interval in the wound state between the pair of negative electrode main bodies 31 adjacent to each other in the expanded state becomes larger as the pair of negative electrode main bodies 31 are located closer to the outer periphery. Therefore, the size of the negative electrode connecting portion 32 in the negative electrode connecting direction increases with increasing distance from the first negative electrode connecting portion 32A, so that the interval between the pair of negative electrode main bodies 31 can be ensured, and the pair of negative electrode main bodies 31 in the wound state with respect to each other. Can be suppressed. Therefore, the displacement of the plurality of negative electrode bodies 31 is suppressed when viewed from the stacking direction.
Moreover, the size of each of the negative electrode main bodies 31 in the negative electrode connecting direction becomes smaller as the distance from the seventh negative electrode main body 31G arranged at the outermost periphery is increased. Thereby, the negative electrode main body 31 on the outer peripheral side of the pair of negative electrode main bodies 31 adjacent to each other in the expanded state is formed larger in the negative electrode connecting direction than the negative electrode main body 31 on the inner peripheral side. Therefore, in the state where the plurality of negative electrode main bodies 31 are overlapped with each other, the negative electrode main body 31 on the outer peripheral side is provided with a non-overlapping region where the negative electrode main bodies 31 on the inner peripheral side do not overlap each other when viewed from the stacking direction. For example, as shown in FIG. 3, a non-overlap region R where the sixth negative electrode body 31F does not overlap is provided in the seventh negative electrode body 31G when viewed from the stacking direction. By disposing the negative electrode connecting portion 32 connected to the negative electrode main body 31 on the inner peripheral side and extending in the stacking direction in a non-overlapping region of the negative electrode main body 31 on the outer peripheral side when viewed from the stacking direction, the negative electrode connecting portion viewed from the stacking direction. It is possible to prevent 32 from protruding from the negative electrode body 31 on the outer peripheral side.
As described above, the displacement of the plurality of negative electrode main bodies 31 and the protrusion of the negative electrode connecting portion 32 from the outermost seventh negative electrode main body 31G are suppressed when viewed from the stacking direction. Therefore, it is possible to provide the battery 1 in which the negative electrode body 30 can be wound into a desired flat shape, the degree of freedom in the shape is improved, and the capacity is ensured.

  Also, if the edge of the negative electrode body exists at the portion where the positive electrode connecting portion faces, lithium ions that have moved from the positive electrode body during charging of the battery are concentrated on the edge of the negative electrode body due to the edge effect and are deposited like needles. there's a possibility that. Thus, if lithium ions are deposited as lithium metal, they may penetrate the separator and short-circuit the negative electrode body and the positive electrode body. In the present embodiment, as described above, the presence of the edge of the negative electrode body 30 in the portion where the positive electrode connecting portion 42 faces is avoided, so that lithium ions can be absorbed by the negative electrode active material of the negative electrode body 30. it can. Therefore, it is possible to suppress deposition of acicular lithium from the negative electrode body 30. Therefore, the reliability of the battery 1 can be improved.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope thereof.
For example, in the above embodiment, a secondary battery has been described as an example of an electrochemical cell, but the present invention is not limited to this, and the above-described configuration may be applied to an electric double layer capacitor, a primary battery, and the like. Moreover, although the lithium ion secondary battery has been described as an example of the battery, the present invention is not limited to this, and a secondary battery other than the lithium ion secondary battery such as a metal lithium secondary battery may be used.
When the above-described configuration is applied to the electric double layer capacitor, the electric double layer capacitor includes a pair of electrodes that are functionally indistinguishable from each other, but one electrode is configured in the same manner as the negative electrode body, and the other electrode is configured. May be configured similarly to the above positive electrode body.

  Further, in the above-described embodiment, the laminated electrode body 2 is formed in an elliptical shape when viewed from the laminating direction, but the present invention is not limited to this, and can be formed in various shapes depending on the shape of the exterior body. For example, the stacked electrode body may be formed in a circular shape or an elliptical shape when viewed from the stacking direction, or may be formed in a quadrangular shape such as a rhombus or a rectangle.

  Further, in the above embodiment, the battery 1 includes the positive electrode terminal and the negative electrode terminal exposed through the through hole of the outer package 3, but the present invention is not limited to this. The battery may include a tab-shaped terminal that extends from the inside of the exterior body to the outside through the space between the first container and the second container in the sealed portion of the exterior body.

  Further, in the above embodiment, the negative electrode terminal is provided in the first container 10 and the positive electrode terminal is provided in the second container 20, but the present invention is not limited to this. That is, the positive electrode terminal may be provided in the first container and the negative electrode terminal may be provided in the second container.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1... Battery (electrochemical cell) 30... Negative electrode body 31... Negative electrode main body 31A... 1st negative electrode main body (inner end side negative electrode main body) 31G... 7th negative electrode main body (outer end side negative electrode main body) 32... Negative electrode connection part 32A... DESCRIPTION OF SYMBOLS 1 Negative electrode connection part (inner end side negative electrode connection part) 34... Curved part (outer edge) 35... Outer edge 40... Positive electrode body 41... Positive electrode main body 42... Positive electrode connection part 42F... Sixth positive electrode connection part (outer end side positive electrode connection part) 44... Curved part (outer edge) 45... Outer edge P1, P2... Inflection point

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first direction in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the pair of outer edges of the positive electrode connecting portion extend in the second direction of the positive electrode body. It is characterized in that it is connected via an inflection point to an outer edge facing in a direction orthogonal to each other.

In addition , the pair of outer edges of the positive electrode connecting portion are smoothly connected to the outer edges of the positive electrode body that are oriented in the direction orthogonal to the second direction. Thereby, it is possible to prevent the stress concentration from occurring at the connecting portion between the outer edge of the positive electrode connecting portion and the outer edge of the positive electrode body, and the positive electrode body from being broken or otherwise damaged. Therefore, the strength of the positive electrode body can be improved.

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body that are superposed on each other and wound flatly, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first state in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the pair of outer edges of the positive electrode connecting portion extend in the second direction of the positive electrode body. It is characterized in that it extends in the shape of an arc tangent to the outer edge facing the orthogonal direction .

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first direction in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the pair of outer edges of the negative electrode connecting portion extend in the first direction in the negative electrode body. It is characterized in that it is connected via an inflection point to an outer edge facing in a direction orthogonal to each other.

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first direction in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the pair of outer edges of the negative electrode connecting portion extend in the first direction in the negative electrode body. It is characterized in that it extends in the shape of an arc tangent to the outer edge facing the orthogonal direction .

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body that are superposed on each other and wound flatly, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first state in a developed state, and a developed body. A pair of the negative electrode bodies that are adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the at least one negative electrode connecting portion is an inner end negative electrode arranged on the innermost periphery. A connecting portion, the at least one positive electrode connecting portion has an outer end side positive electrode connecting portion arranged at the outermost periphery, and the minimum interval between the pair of outer edges in each of the at least one negative electrode connecting portion is It is characterized in that it becomes smaller with distance from the inner end side negative electrode connecting portion, and the minimum distance between the pair of outer edges in each of the at least one positive electrode connecting portion becomes larger with increasing distance from the outer end side positive electrode connecting portion .

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first direction in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body, and the plurality of negative electrode bodies are outer end side negative electrode bodies arranged on the outermost periphery, and An inner end side negative electrode main body arranged on the innermost periphery, wherein the at least one negative electrode connecting portion includes an inner end side negative electrode connecting portion connected to the inner end side negative electrode main body, The dimension in the first direction decreases as the distance from the outer end side negative electrode main body decreases, and the dimension in the first direction of each of the at least one negative electrode connecting portion increases as the distance from the inner end side negative electrode connecting portion increases. It is characterized by

The electrochemical cell of the present invention includes a negative electrode body and a positive electrode body which are superposed on each other and wound in a flat shape, and the negative electrode body has a plurality of negative electrode bodies arranged side by side in a first direction in a developed state, and a developed body. A pair of negative electrode bodies adjacent to each other in a state, a negative electrode active material is disposed on the surface, and the pair of negative electrode bodies are folded back so as to overlap each other, and at least one negative electrode connecting portion is provided, and the positive electrode body Is arranged in the unfolded state side by side in the second direction, and connects a plurality of positive electrode bodies that overlap the negative electrode body to a pair of the positive electrode bodies that are adjacent in the unfolded state, and a positive electrode active material is placed on the surface of the negative electrode body. At least one positive electrode connecting portion facing the connecting portion, and the at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction, and the at least one positive electrode connecting portion. Has a pair of outer edges facing in a direction orthogonal to the second direction, the pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in an intermediate portion in the first direction, and the positive electrode connecting portion is The pair of outer edges are recessed so as to approach each other in the middle portion in the second direction, and face the main surface of the negative electrode body, and the positive electrode active material contains a lithium compound .

Claims (8)

A negative electrode body and a positive electrode body which are superposed on each other and are wound flatly,
The negative electrode body is
A plurality of negative electrode main bodies arranged side by side in the first direction in an expanded state,
At least one negative electrode connecting portion that connects a pair of adjacent negative electrode bodies in a developed state, has a negative electrode active material disposed on the surface, and is folded back so that the pair of negative electrode bodies overlap each other,
Have
The positive electrode body is
A plurality of positive electrode main bodies that are arranged side by side in the second direction in an expanded state and overlap the negative electrode main body;
At least one positive electrode connecting portion that connects the pair of positive electrode main bodies adjacent to each other in a developed state, the positive electrode active material is disposed on the surface, and faces the negative electrode connecting portion,
Have
The at least one negative electrode connecting portion has a pair of outer edges facing a direction orthogonal to the first direction,
The at least one positive electrode connecting portion has a pair of outer edges facing a direction orthogonal to the second direction,
The pair of outer edges of the negative electrode connecting portion are recessed so as to approach each other in the intermediate portion in the first direction,
The pair of outer edges of the positive electrode connecting portion are recessed so as to approach each other in the intermediate portion in the second direction, and face the main surface of the negative electrode body.
An electrochemical cell characterized by the above. The pair of outer edges of the positive electrode connecting portion are connected to an outer edge of the positive electrode body that faces a direction orthogonal to the second direction via an inflection point.
The electrochemical cell according to claim 1, wherein: The pair of outer edges of the positive electrode connecting portion extend in an arc shape that is tangent to the outer edge of the positive electrode body that faces a direction orthogonal to the second direction.
The electrochemical cell according to claim 1, wherein: The pair of outer edges of the negative electrode connecting portion are connected to an outer edge of the negative electrode body which faces a direction orthogonal to the first direction via an inflection point.
The electrochemical cell according to any one of claims 1 to 3, wherein: The pair of outer edges of the negative electrode connecting portion extend in an arc shape that is tangent to the outer edge of the negative electrode body that faces a direction orthogonal to the first direction.
The electrochemical cell according to any one of claims 1 to 3, wherein: The at least one negative electrode connecting portion has an inner end side negative electrode connecting portion arranged on the innermost periphery,
The at least one positive electrode connecting portion has an outer end side positive electrode connecting portion arranged on the outermost periphery,
The minimum distance between the pair of outer edges in each of the at least one negative electrode connecting portion becomes smaller with increasing distance from the inner end side negative electrode connecting portion,
The minimum distance between the pair of outer edges in each of the at least one positive electrode connecting portion increases as the distance from the outer end side positive electrode connecting portion increases.
The electrochemical cell according to any one of claims 1 to 5, wherein: The plurality of negative electrode bodies have an outer end side negative electrode body disposed on the outermost periphery and an inner end side negative electrode body disposed on the innermost periphery,
The at least one negative electrode connecting portion includes an inner end side negative electrode connecting portion connected to the inner end side negative electrode main body,
The dimension of each of the plurality of negative electrode main bodies in the first direction becomes smaller with increasing distance from the outer end side negative electrode main body,
A dimension in the first direction of each of the at least one negative electrode connecting portion increases with increasing distance from the inner end side negative electrode connecting portion,
The electrochemical cell according to any one of claims 1 to 6, characterized in that The positive electrode active material includes a lithium compound,
The electrochemical cell according to any one of claims 1 to 7, wherein:

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