JP2017054716A - Flat type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in an electrode structure of a conventional flat type battery, since connection parts connecting a plurality of electrode parts are provided in the same direction, the connection parts are overlapped in the same direction, thereby disabling thickness from being sufficiently reduced.SOLUTION: In a flat type battery, a positive electrode plate and a negative electrode plate in a band plate shape with an active material layer formed on a surface are formed, and an electrode group 40 is formed by oppositely folding a positive electrode plate 41 and a negative electrode plate 43. The positive electrode plate 41 and the negative electrode plate 43 include a plurality of electrode parts (411-415 and 431-435) in the same shape and a plurality of connection parts (411t-415t and 431t-435t) each connecting the adjacent electrode parts. In the case where the electrode group is formed by folding the electrode plates at the respective connection parts, the connection parts (411t-415t and 431t-435t) are disposed so as not to overlap each other in a planar view watching the electrode group from a top face.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flat battery in which an electrode group in which a plurality of layers of active material layers are formed is contained in a storage body, and more particularly to a flat battery in consideration of processing of a fold portion constituting the electrode group.

  In the battery, positive and negative electrode plates, each having an active material layer (a mixture of a predetermined active material and a binder agent) provided on the surface of a metal foil, are opposed to each other while being electrically insulated through a separator. It has a structure in which an electrolyte is interposed.

  The configuration in which the electrode plates are opposed to each other is called an electrode group, this electrode group is housed in a battery case of a predetermined shape, and a positive electrode and a negative electrode are electrically connected to predetermined electrode terminals of the battery case, respectively. Functions as a primary or secondary battery.

  In many cases, a flat battery represented by a button type or a coin cell type has a battery case made of metal and serves also as an electrode terminal of each polarity. In this battery case, a case serving as a positive electrode terminal and a case serving as a negative electrode terminal are fixed by fitting, bonding, or the like in an electrically insulated state.

  Particularly in recent years, with the advancement of portable electronic devices such as high-function mobile phones and small information terminals, batteries to be mounted are increasingly required to be smaller and thinner, and there are more opportunities to adopt flat batteries. Yes. At the same time, the power consumption of the devices tends to increase due to the multi-functionalization of such electronic devices, and flat primary and secondary batteries with larger battery capacities are demanded. From such a background, a flat battery having a high discharge rate in the case of a primary battery, a high charge / discharge rate in the case of a secondary battery, and having a small size and a large capacity is demanded.

  Since this flat battery is small and thin, it is not possible to secure a sufficient amount of electricity storage by simply facing the positive electrode plate and the negative electrode plate in a limited space of the battery case. Therefore, in order to obtain a larger amount of power storage, a strip-shaped positive electrode plate and a negative electrode plate having a larger area than the battery case are used, and the positive and negative electrode plates are folded back via a separator. Has been proposed to increase the area of the electrode plate and to prevent the electrode plate from being short-circuited (see, for example, Patent Document 1).

Patent Document 1 will be described with reference to FIG. FIG. 20 is a cross-sectional view illustrating an electrode structure of a coin-type lithium ion secondary battery described in Patent Document 1.
As shown in FIG. 20, the coin-type lithium ion secondary battery of Patent Document 1 includes a pair of strip-shaped positive electrode 102 and negative electrode 103, and a gap 106 that separates the pair of positive electrode 102 and negative electrode 103 from each other. And the electrode body layer 105 laminated on the pair of positive electrodes 102 and the negative electrode 103, and the pair of strip-shaped positive electrodes 102 and the negative electrode 103 are alternately bent in different directions for each predetermined length, and the positive electrode 102 and the negative electrode The electrode portion of any one electrode plate 103 and the electrode portion of the other electrode plate 103 are alternately laminated to form a laminate.

  With this structure, the connecting portion obtained by folding the pair of the positive electrode 102 and the negative electrode 103 into the ninety-nine folds faces in the same direction, so that the thick bulge portion 105a of the connecting portion is folded to increase the thickness of the laminated electrode. It is difficult to reduce the thickness when the battery case is stored. As shown in FIG. 20, as a measure against this thinness, the positions of the connecting portions are shifted every other place, and the positions of the edges 1051 to 1054 of the folded portions are alternately arranged so that the thickness of the connecting portions is not overlapped. Thus, an electrode structure in which the thickness of the stacked electrode is reduced is described.

Japanese Patent Application Laid-Open No. 08-064225 (page 2-3, FIG. 1)

However, in the electrode structure of the coin-type lithium ion secondary battery described in the cited document 1, the thickness of the laminated electrode is reduced so as not to overlap the thickness of the connecting portion by shifting the location of every other connecting portion. Although the thickness is reduced, the connecting portions are overlapped in the same direction, so the thickness cannot be sufficiently reduced. In addition, it is difficult to manage the shift amount, and if the shift amount is insufficient, the thick portions overlap and do not become thin, and if the shift amount is excessive, there is a risk that the maximum outer dimension becomes too large to fit in the case.
Furthermore, the gap between the electrodes becomes non-uniform by shifting the position with respect to the connecting portions of the layers, so that the uniformity of the distance between the electrodes is lost. For example, in the case of a lithium ion secondary battery, between the two electrodes Therefore, the movement of lithium ions becomes non-uniform, and there is a risk that charge / discharge characteristics as a secondary battery, that is, cycle characteristics may deteriorate.

  An object of the present invention is to solve the above problems. That is, an electrode structure of a flat battery in which an electrode portion of an electrode plate joined at a connecting portion and an electrode portion of the other electrode plate are alternately stacked to form a ninety-nine-fold stacked body. The present invention provides a flat battery that can be thinned as a whole when the electrode group is formed by devising the arrangement of the connecting portion, and the charge / discharge characteristics as a secondary battery, that is, the cycle characteristics are good. It is.

  In order to solve the above problems, the flat battery of the present invention adopts the following configuration.

  The flat battery of the present invention is a flat battery in which an electrode group is formed by folding a positive electrode plate and a negative electrode plate each having an active material layer formed on the surface thereof, and the positive electrode plate and the negative electrode plate are opposed to each other. The positive electrode plate and the negative electrode plate each have a plurality of electrode portions having the same shape and a plurality of connection portions that connect adjacent electrode portions, and are folded at each connection portion to form an electrode group. The electrode groups are arranged at positions where they do not overlap each other in a plan view when the electrode group is viewed from above.

  With the above configuration, when the electrode group is formed by folding, the positions of the connecting portions that connect the electrode portions are arranged at different positions, and the connecting portions do not overlap each other, so the thickness of the connecting portion does not increase.

  Furthermore, it is desirable to have a structure in which the positive electrode plate and the negative electrode plate are folded in ninety-nine folds.

  Thereby, since the positive electrode plate and the negative electrode plate can be efficiently laminated, a flat battery having a small size and a minimum thickness corresponding to the battery capacity can be realized.

According to the present invention, since the connecting portions are stacked at different positions, the thickness of the connecting portions does not increase. Further, at the stage of forming the electrode plate, the connecting portion take-out angle and the shape of the connecting portion can be accurately set, so that there is no problem that the connecting portion becomes thick and the electrode structure does not fit in the case.
Furthermore, the gap between the electrodes is made uniform by properly shifting the position of the connecting portion with respect to the electrode layers of several layers, and the uniformity of the distance between the electrodes is maintained. For example, in the case of a lithium ion secondary battery, lithium The uniformity of ion movement can be maintained, and the charge / discharge characteristics, that is, the cycle characteristics as the secondary battery are improved.

It is the top view and sectional drawing which show the structure of the electrode group of the flat battery 1 in 1st Embodiment of this invention. It is the top view and sectional drawing of the positive electrode plate and negative electrode plate which comprise the electrode group shown in FIG. It is a top view which shows the manufacturing method of the electrode group shown in FIG. It is the top view and partial sectional view which show the manufacturing method of the electrode group following FIG. FIG. 5 is a plan view showing a manufacturing method of the electrode group following FIG. 4 and a sectional view of the completed electrode group. It is a perspective view which shows the state which incorporates the electrode group shown in FIG. 1 in a battery case. It is sectional drawing which shows the structure of the flat battery 1 in 1st Embodiment of this invention. It is a flowchart which shows the design process of the electrode group shown in FIG. It is a top view which shows the manufacturing method of the electrode group of the flat battery 2 of the 1st modification in 1st Embodiment of this invention. FIG. 10 is a plan view showing a method for manufacturing the electrode group of the flat battery 2 following FIG. 9. It is a top view which shows the manufacturing method of the electrode group of the flat battery 2 following FIG. It is a top view which shows the manufacturing method of the electrode group of the flat battery 3 of the 2nd modification in 1st Embodiment of this invention. It is a top view which shows the manufacturing method of the electrode group following FIG. It is a top view which shows the manufacturing method of the electrode group of the flat battery 4 in 2nd Embodiment of this invention. It is a top view which shows the manufacturing method of the electrode group following FIG. FIG. 16 is a plan view illustrating a method for manufacturing the electrode group following FIG. 15. It is a top view which shows the manufacturing method of the electrode group of the flat battery 5 in 3rd Embodiment of this invention. FIG. 18 is a plan view showing a method for manufacturing the electrode group following FIG. 17. It is a top view which shows the manufacturing method of the electrode group following FIG. It is sectional drawing which shows the structure of the conventional flat battery.

  The present invention relates to a flat battery having an electrode group formed by laminating a positive electrode plate and a negative electrode plate, and a plurality of positive electrode portions and a plurality of connecting portions that connect the negative electrode portions provided in each of the positive electrode plate and the negative electrode plate. Are arranged at a predetermined angle or interval to prevent the overlapping of the connecting portions when folded into an electrode group, thereby providing a thin battery with a thin and high capacity.

  The shape of the positive electrode plate or the negative electrode plate in the present invention is a band plate-like structure in which a plurality of positive electrode portions or negative electrode portions having the same shape are connected by an elongated band-like connecting portion. In the following description, “positive electrode part” or “negative electrode part” may be simply expressed as “electrode part”. Furthermore, the “positive electrode plate” or “negative electrode plate” may be collectively referred to as “electrode plate”.

The aspect of the present invention includes the first to third embodiments as described below, and the first embodiment further includes the first embodiment, the first modification of the first embodiment, and the first embodiment. And a second modification of the embodiment.
The configuration of the flat battery in the first embodiment is an electrode group in which a strip-shaped positive electrode plate and a negative electrode plate in which a plurality of positive electrode portions and negative electrode portions are connected by a connecting portion are stacked by ninety-nine folds. Then, the angle of the outer periphery of the electrode part, that is, the angle of the connecting part arranged around the electrode group is calculated by dividing the angle of the outer periphery of the electrode part by the number of connecting parts of the strip-like electrode plate. Then, from the number of the electrode portions of the positive electrode plate and the negative electrode plate, the number of connecting portions and the calculated take-off angle between the connecting portions, the overlapping of the positive electrode plate and the negative electrode plate at the beginning of the ninety-nine fold forming the electrode group 40 The alignment angle is set, and the positive electrode plate and the negative electrode plate are stacked by 99-fold.

[First embodiment]
In the first embodiment, there are five positive electrode portions and four negative electrode portions (four connection portions), the take-out angle between the connection portions is 90 degrees, and the shape of each electrode portion is a regular octagon. Will be described.

[Description of First Embodiment: FIGS. 1 to 8]
Hereinafter, a flat battery according to a first embodiment will be described with reference to the drawings.
1 to 8 relate to the first embodiment, FIG. 1 is a plan view and a sectional view showing the structure of the electrode group of the flat battery 1 in the first embodiment of the present invention, and FIG. 2 shows the electrode group shown in FIG. FIG. 3 is a plan view showing a manufacturing method of the electrode group shown in FIG. 1, and FIG. 4 is a manufacturing method of the electrode group following FIG. FIG. 5 is a plan view showing a manufacturing method of the electrode group following FIG. 4 and a sectional view of the completed electrode group. FIG. 6 shows a state in which the electrode group shown in FIG. FIG. 7 is a cross-sectional view showing the structure of the flat battery 1, and FIG. 8 is a flowchart showing the design process of the electrode group of the flat battery 1.

  The structure of the electrode group 40 which is a main element of the flat battery 1 in the first embodiment will be described with reference to FIG. 1A is a plan view showing the structure of the electrode group 40, and FIG. 1B is a cross-sectional view taken along the line AA ′ of the electrode group 40 shown in FIG.

As shown in FIG. 1A, the electrode group 40 in which the positive electrode plate 41 and the negative electrode plate 43 are folded has a regular octagonal shape in plan view, and is the midpoint of each side of the positive electrode plate 41 and the negative electrode plate 43. Eight folded connecting portions 411t to 414t and connecting portions 431t to 434t protrude at right angles.
That is, positive electrode connecting portions 411t to 414t and negative electrode connecting portions 431t to 434t are alternately provided for each octagonal side of the electrode group 40.

  As shown in FIG. 1B, the electrode group 40 is formed by alternately stacking positive plates 41 and negative plates 43 by a method known as a ninety-nine fold. FIG. 1B shows a connecting portion 412t and a connecting portion 414t on the A-A ′ cross section of the electrode group 40 shown in FIG.

  Next, the formation method of the electrode group 40 is demonstrated using FIG. FIG. 2A is a plan view for explaining the structure of the positive electrode plate 41 forming the electrode group 40, and FIG. 2B is a cross-sectional view of the positive electrode plate 41 shown in FIG. .

  2C is a plan view for explaining the structure of the negative electrode plate 43 forming the electrode group 40, and FIG. 2D is a cross-sectional view taken along the line C-C 'of the negative electrode plate 43 shown in FIG. is there.

  As shown in FIG. 2A, the positive electrode plate 41 includes five positive electrode portions 411 to 415 having a regular octagonal shape in a plan view, and connecting portions 411t to 414t (the symbols 413t and 414t are not shown). It is formed by joining. Of the five positive electrode portions 411 to 415, the positive electrode portions 412, 413, and 414 excluding the positive electrode portion 411 and the positive electrode portion 415 arranged at the end portions each include two connecting portions. . The angle formed by the two connecting portions is the take-out angle, and in this embodiment, the take-out angle θ1 is 90 degrees. Although the positive electrode plate 41 is encased in a separator, it is not shown because it is not directly related to the present invention.

[Structure Explanation of Positive Electrode Plate in First Embodiment: FIGS. 2A and 2B]
As shown in FIG. 2B, the positive electrode plate 41 is formed by forming a positive electrode-side active material layer 41k on both surfaces of the positive electrode foil 41m using aluminum (hereinafter referred to as Al) except for the connecting portion 411t. ing. The active material layer 41k is a mixture of a positive electrode active material, a conductive agent, and a binder agent. The active material coated surface is not limited to both surfaces, and the active material may not be present on the surface that comes into contact with the positive electrode outer can after assembly.
In this embodiment, the active material layer is not provided in the connecting portion in consideration of bendability, but considering the manufacturing process, it is easier to form the active material layer collectively on the electrode plate and the connecting portion. Part of the active material layer may or may not be provided.

[Description of Structure of Negative Electrode Plate in First Embodiment: FIGS. 2C and 2D]
As shown in FIG. 2 (c), the negative electrode plate 43 includes five negative electrode parts 431 to 435 having a regular octagonal shape in plan view and connecting parts 431t to 434t (reference numerals of 432t to 434t are not shown). As with the positive electrode plate 41, the take-out angle θ1 between the connecting portions is 90 degrees.

  As shown in FIG. 2 (d), the negative electrode plate 43 includes a negative electrode foil 43m made of copper (hereinafter referred to as Cu) with active material layers 43k on the negative electrode side on both surfaces excluding the connecting portions 431t to 434t. Forming. The active material layer 43k is a mixture of a negative electrode active material, a conductive agent, and a binder agent. The active material coated surface is not limited to both surfaces, and the active material may not be present on the surface that contacts the negative electrode outer can after assembly.

[Description of Manufacturing Method of Electrode Group 40 in First Embodiment: FIGS. 3 to 5]
Next, an electrode group forming method will be described with reference to FIGS. FIG. 3A to FIG. 3C are plan views showing an electrode group forming process by ninety-nine folds of the positive electrode plate 41 and the negative electrode plate 43.

  First, as shown in FIG. 3A, the connecting portion 411t of the positive electrode plate 41 and the connecting portion 431t of the negative electrode plate 43 are arranged so as to be shifted by 45 degrees in a plan view, and on the positive electrode portion 411 of the positive electrode plate 41. The negative electrode part 431 of the negative electrode plate 43 is overlapped.

  Next, as shown in FIG. 3B, a fold line B1 that intersects the connecting portion 411t of the positive electrode plate 41 at a right angle is defined. The positive electrode plate 41 is folded in the direction of the arrow F1 with the fold line B1 as a valley. As a result, the positive electrode portion 412 of the positive electrode plate 41 overlaps the negative electrode portion 431 of the negative electrode plate 43. That is, the state shown in FIG.

  Next, as shown in FIG. 3C, a fold line B2 that intersects the connecting portion 432t of the negative electrode plate 43 at a right angle is defined. Then, the negative electrode plate 43 is folded in the direction of the arrow F2 with the fold line B2 as a valley. As a result, the negative electrode portion 432 of the negative electrode plate 43 overlaps the positive electrode portion 412 of the positive electrode plate 41.

  In addition, in the state before folding of FIG. 3C, a part of the positive electrode part 414 overlaps with the negative electrode part 432 and is difficult to fold. Therefore, for easy folding of the negative electrode plate 43, FIG. For example, the length L of the connecting portion shown in FIG. 3C is set to 50% of the diagonal dimension of the negative electrode portion 432, so that the amount of overlap between the electrodes needs to be reduced by considering the structure.

The electrode group formation method following FIG. 3 will be described with reference to FIGS. 4 (a) to 4 (d).
As shown in FIG. 4A, a fold line B3 that intersects with the connecting portion 412t of the positive electrode plate 41 at a right angle is defined. The positive electrode plate 41 is folded in the direction of the arrow F3 with the fold line B3 as a valley. As a result, the positive electrode portion 413 of the positive electrode plate 41 overlaps the negative electrode portion 432 of the negative electrode plate 43.

  Next, as shown in FIG. 4B, a fold line B4 that intersects the connecting portion 433t of the negative electrode plate 43 at a right angle is defined. Then, the negative electrode plate 43 is folded in the direction of the arrow F4 with the fold line B4 as a valley. As a result, the negative electrode portion 433 of the negative electrode plate 43 overlaps the positive electrode portion 413 of the positive electrode plate 41. Since the method for easily folding the negative electrode plate 43 has been described above, the description thereof will be omitted.

  Next, as shown in FIG. 4C, a fold line B5 that intersects the connecting portion 414t of the positive electrode plate 41 at a right angle is defined. Then, the positive electrode plate 41 is folded in the direction of the arrow F5 with the fold line B5 as a valley. As a result, the positive electrode portion 414 of the positive electrode plate 41 overlaps the negative electrode portion 433 of the negative electrode plate 43.

  The cross-sectional structure of the electrode group 40 after the steps of FIGS. 3A to 4C will be described with reference to FIG. FIG. 4D is an XX ′ cross section of the electrode group 40 folded in the steps up to FIG. 4C, the positive electrode portion 411 is the lowermost layer, and the negative electrode portion 431 is laminated thereon, and thereafter This is repeated twice to form three pairs of electrode portions on the positive electrode side and the negative electrode side. In FIG. 4D, the connecting portion 412t connects the positive electrode portion 412 and the positive electrode portion 413.

The electrode group formation method following FIG. 4 will be described with reference to FIGS. 5 (a) to 5 (e).
As shown in FIG. 5A, a fold line B6 that intersects the connecting portion 433t of the negative electrode plate 43 at a right angle is defined. Then, the negative electrode plate 43 is folded in the direction of the arrow F6 with the fold line B6 as a valley. As a result, the negative electrode portion 434 of the negative electrode plate 43 overlaps the positive electrode portion 414 of the positive electrode plate 41.

  Next, as shown in FIG. 5B, a fold line B7 that intersects the connecting portion 414t of the positive electrode plate 41 at a right angle is defined. Then, the positive electrode plate 41 is folded in the direction of the arrow F7 with the fold line B7 as a valley. As a result, the positive electrode portion 415 of the positive electrode plate 41 overlaps the negative electrode portion 434 of the negative electrode plate 43.

  Next, as shown in FIG. 5C, a fold line B8 that intersects the connecting portion 434t of the negative electrode plate 43 at a right angle is defined. Then, the negative electrode plate 43 is folded in the direction of the arrow F8 with the fold line B8 as a valley. As a result, the negative electrode portion 435 of the negative electrode plate 43 overlaps the positive electrode portion 415 of the positive electrode plate 41.

Through the above steps, as shown in FIG. 5D, the negative electrode portion 435 is arranged on the uppermost layer, and the electrode group 40 is completed. The connecting portions 411t to 414t and the connecting portions 431t to 434t are arranged so as not to alternately overlap from the midpoint of each side of the electrode group 40 in a plan view when the electrode group 40 is viewed from above.
FIG. 5E is a GG ′ cross section of FIG. 5D, and shows a connecting portion 412 t and a connecting portion 414 t.

[Description of incorporation of electrode group 40 into battery case: FIG. 6]
Next, a process of incorporating the completed electrode group 40 into the battery case will be described with reference to FIG. FIG. 6 shows a battery case composed of an outer case (positive electrode outer can) 10 which is an external terminal on the positive electrode side, a sealing case (negative electrode outer can) 30 which is an outer terminal on the negative electrode side, and a gasket 20; It is a perspective view explaining the method of assembling.

  As shown in FIG. 6, the electrode group 40 is housed in the outer case 10, and the positive electrode plate 41 of the electrode group 40 and the outer case 10 are electrically connected by a welding method. Although not shown, an electrolytic solution is injected, the negative electrode plate 43 of the electrode group 40 and the sealing case 30 are electrically connected by pressing, and the outer case 10 and the sealing case 30 are fitted with the gasket 20 interposed therebetween. Then, the flat battery 1 is completed.

[Description of Overall Structure of Flat Battery 1 of First Embodiment: FIG. 7]
The overall structure of the flat battery 1 will be described with reference to FIG. FIG. 7 is a cross-sectional view of the central portion of the flat battery 1. As shown in FIG. 7, the flat battery 1 includes a positive electrode plate 41 in a battery case 15 including an outer case 10 that is an external terminal on the positive electrode side, a sealing case 30 that is an external terminal on the negative electrode side, and a gasket 20. The electrode group 40 is formed by stacking a negative electrode plate 43 and a separator (not shown) in five layers.

[Effect of the flat battery of the first embodiment: FIG. 5 (d)]
Next, the effect of the flat battery 1 according to the first embodiment will be described with reference to FIG.
FIG. 5D is a plan view of the completed electrode group 40 of the flat battery 1 according to the first embodiment. As shown in FIG. 5D, in the electrode group 40, the connecting portions 411 t to 414 t of the eight positive electrode plates 41 and the connecting portions 431 t to 434 t of the negative electrode plate 43 are equally formed on the eight sides of the electrode group 40. Yes.

Since the connecting portions 411t to 414t and the connecting portions 431t to 434t are evenly shifted and arranged at different positions, the thickness at each location does not increase. Also, at the stage of forming the electrode plate, the shift amount for each connecting portion and the shape of the connecting portion can be set accurately, so that the connecting portion becomes thick due to insufficient shift amount, excessive shift amount, etc. There is no problem of not being able to fit.
Furthermore, with respect to multiple layers of connecting portions, by appropriately arranging the positions of the connecting portions, the gap between the electrodes becomes uniform and the uniformity of the distance between the electrodes is maintained. For example, in the case of a lithium ion secondary battery It is also possible to maintain the uniformity of lithium ion movement, and charge / discharge characteristics, that is, cycle characteristics as a secondary battery are improved.

[Description of Design Method of Electrode Group 40 in First Embodiment: FIG. 8]
Next, the design method will be described with reference to FIG. 8 taking the positive electrode plate 41 and the negative electrode plate 43 of the electrode group 40 of the flat battery 1 of the present invention as an example. FIG. 8 is a flowchart for explaining the design procedure of the positive electrode plate 41 and the negative electrode plate 43 of the electrode group 40 of the flat battery 1. As shown in FIG. 8, the flowchart of the design method of the positive electrode plate 41 and the negative electrode plate 43 is composed of ST1 to ST5.

  In the battery specification specification setting step ST1, first, the specification of the flat battery is determined. Examples are items such as necessary capacity, external dimensions, thickness, etc. of the flat battery.

  In the electrode part number setting step ST2, the capacity set in the battery specification specification setting process ST1, the electrode part 1 of the positive electrode parts 411 to 415 and the negative electrode parts 431 to 435 constituting the positive electrode plate 41 and the negative electrode plate 43 are provided. The number of necessary electrode portions is calculated from the capacity per pair. That is, the number of necessary electrode parts = (capacity of flat battery) / (capacity per pair of electrode parts).

  In the total number setting step ST3 of the connecting parts, the number of connecting parts for connecting the electrode parts is calculated from the number of electrode parts set in the electrode part number setting step ST2. An example of the calculation method is the number of connected parts = (number of electrode parts−1).

  In the connecting portion angle setting step ST4, the angle between the connecting portions arranged on the outer peripheral portion of the electrode portion is calculated from the number of connecting portions set in the electrode portion number setting step ST3. As an example of the calculation method, the extraction angle between the connecting portions = (360 degrees / number of connecting portions). In addition, you may multiply the taking-out angle between the obtained connection parts by an integral multiple. However, the take-off angle is preferably 60 to 180 degrees in order to easily manufacture the electrode group 40. However, depending on the shape of the electrode part and the length of the connecting part, it can be manufactured even at an angle smaller than 60 degrees.

  The overlapping angle setting step ST5 of the 99-folding step includes the number of electrode portions of the positive and negative electrode plates, the number of connecting portions, and the number of connecting portions taken out in the electrode portion number setting step ST2 to the connecting portion angle setting step ST4. From the angle, the overlapping angle of the positive electrode plate and the negative electrode plate at the beginning of the ninety-nine fold forming the electrode group 40 is set. As an example of the setting method, the angle of superposition = (takeout angle between connecting parts / 2) × n. However, n is preferably an odd number of 1 or more.

  The design of the positive electrode plate 41 and the negative electrode plate 43 constituting the electrode group 40 is completed by the above steps. In the first embodiment described above, based on the design method of FIG. 8, the number of electrode portions is “5”, so the number of connection portions is 5-1 = 4 and “4”. The take-out angle between the connecting portions is 360/4 = 90, 90 degrees, and the overlapping angle is n = 1, 90/2 × 1 = 45, 45 degrees.

[First Modification of First Embodiment]
Next, a first modification of the first embodiment will be described. In the first modification, there are 6 positive electrode portions and 5 negative electrode portions (5 connection portions), the take-out angle between the connection portions is 72 degrees, and the shape of each electrode portion is a regular decagon.

[Explanation of First Modification: FIGS. 9 to 11]
Next, a method of forming the electrode group 40p of the flat battery 2 in the first modification will be described with reference to FIGS.

  The characteristics of the electrode group 40p in the first modified example are that the shape of the positive electrode plate 41p and the negative electrode plate 43p in a plan view is a regular decagon compared to the electrode group 40 in the first embodiment, and the positive electrode plate 41p and the negative electrode That is, the number of the plates 43p is one more, and the take-out angle θ2 between the connecting portions of the positive plate 41p and the negative plate 43p is 72 degrees. Other structures and elements are the same as those in the first embodiment.

  FIG. 9A to FIG. 9C are plan views showing manufacturing steps of the electrode group 40p in the second embodiment. FIG. 9A to FIG. 9C are plan views showing the first step of the electrode group formation step by folding the positive electrode plate 41p and the negative electrode plate 43q of the electrode group 40p. First, as shown in FIG. 9A, the connecting portion 411pt of the positive electrode plate 41p and the connecting portion 431pt of the negative electrode plate 43p are arranged on the same line, that is, at 180 degrees as the overlapping angle, as shown in FIG. As shown, the positive electrode portion 411p of the positive electrode plate 41p is overlaid on the negative electrode portion 431p of the negative electrode plate 43p.

  Next, as shown in FIG. 9B, a fold line B1 is defined which intersects the connecting portion 431pt of the negative electrode plate 43p at a right angle. Then, the negative electrode plate 43p is folded in the direction of the arrow F1 with the fold line B1 as a valley. Thereby, the negative electrode part 432p of the negative electrode plate 43p overlaps with the positive electrode part 411p of the positive electrode plate 41p.

  Next, as shown in FIG. 9C, a fold line B2 that intersects the connecting portion 411pt of the positive electrode plate 41p at a right angle is defined. Then, the positive electrode plate 41p is folded in the direction of the arrow F2 with the fold line B2 as a valley. Thereby, 412p of the positive electrode plate 41p overlaps with the negative electrode portion 432p of the negative electrode plate 43p.

  FIG. 10A to FIG. 11E are plan views for explaining an electrode group forming method subsequent to FIG. 10 (a), the positive electrode plate 41p and the negative electrode plate 43p are arranged in the direction of F3 with B3 as a valley, and in FIG. 10 (b), in the direction of F4 with B4 as a valley, in FIG. 10 (c), Ninety-nine folds are sequentially performed in the direction of F5 with B5 as a valley, and in FIG. 10D, in the direction of F6 with B6 as a valley.

  Similarly, in FIG. 11A, B7 is a valley and is in the direction of F7. In FIG. 11B, B8 is a valley and is in the direction of F8. In FIG. In FIG. 11D, ninety nine folds are sequentially performed in the direction of F10 with B10 as a valley.

Through the above steps, as shown in FIG. 11E, an electrode group 40p having a positive electrode portion 416p as the uppermost layer is completed. Connecting portions 411pt to 415pt and connecting portions 431pt to 435pt are alternately arranged from the midpoint of each side of the electrode group 40p.

  The electrode group 40p completed through the above steps is assembled into a battery case to complete a flat battery, but the description of the incorporation process is omitted because it is the same as in the first embodiment.

  As shown in FIG. 11 (e), in the plan view of the electrode group 40p as viewed from above, the ten connecting portions 411t to 415t and the connecting portions 431t to 435t in the electrode group 40p are overlapped on the 10 sides of the electrode group 40p. It is arranged not to become. The details of the effect of the flat battery of the first modification are the same as those of the first embodiment, and thus the description thereof is omitted.

  The first modified example is also based on the design method of FIG. 8, and the number of electrode portions is “6”. Therefore, the number of connecting portions is 6-1 = 5, which is “5”. The take-out angle is 360/5 = 72 and 72 degrees, and the superposition angle is n = 5 and 72/2 × 5 = 180 and 180 degrees.

[Second Modification of First Embodiment]
Next, a second modification will be described. In the second modified example, the number of positive electrode portions and the number of negative electrode portions are six (five connection portions), the take-out angle between the connection portions is 144 degrees, and the shape of each electrode portion is a regular decagon.

[Explanation of Second Modification: FIGS. 12 to 13]
A method of forming the electrode group electrode group 40q of the flat battery 3 in the second modification will be described with reference to FIGS. 12 (a) to 13 (b) are plan views showing the steps of an electrode group forming process by folding the positive electrode plate 41q and the negative electrode plate 43q of the electrode group electrode group 40q in the second modification.

  The feature of the electrode group 40q in the second modification is that the take-out angle θ3 between the connecting portions of the positive electrode plate 41q and the negative electrode plate 43q is as large as 144 degrees compared to the electrode group 40p in the first modification. Other structures and elements are the same as those in the first modification.

  First, as shown in FIG. 12 (a), the connecting portion 411qt of the positive electrode plate 41q and the connecting portion 431qt of the negative electrode plate 43q are arranged on the same line, that is, with a superposition angle of 180 degrees. As shown, the positive electrode portion 411q of the positive electrode plate 41q is overlaid on the negative electrode portion 431q of the negative electrode plate 43q.

  Next, as shown in FIG. 12B, a fold line B1 is defined which intersects the connecting portion 431qt of the negative electrode plate 43q at a right angle. Then, the negative electrode plate 43q is folded in the direction of the arrow F1 with the fold line B1 as a valley. Thereby, the negative electrode part 432q of the negative electrode plate 43q overlaps with the positive electrode part 411q of the positive electrode plate 41q.

  FIG. 13A and FIG. 13B are plan views for explaining the electrode group forming method subsequent to FIG. As shown in FIGS. 13 (a) and 13 (b), fold lines that intersect at right angles with the connecting portion 411qt of the positive electrode plate 41q and the connecting portion 432pt of the negative electrode plate 43q are defined as B2 and B3, respectively. Then, with the fold lines B2 and B3 as valleys, the positive electrode plate 41q and the negative electrode plate 43q are folded in the directions of arrows F2 and F3, respectively. Thereby, 412q of the positive electrode plate 41q overlaps with the negative electrode portion 432q of the negative electrode plate 43q, and the negative electrode portion 433q of the negative electrode plate 43q overlaps with 412q of the positive electrode plate 41q.

Further, the similar 99-folding process is repeated, and finally 40q having the negative electrode portion 431q as the uppermost layer is completed as shown in FIG. 13C. Connecting portions 411qt to 415qt and connecting portions 431qt to 435qt are arranged from the midpoint of each side of the electrode group 40q.

  The electrode group 40q completed through the above steps is incorporated into a battery case to complete a flat battery. However, since the incorporation steps and effects are the same as those in the first embodiment, description thereof is omitted.

  The second modified example is also based on the design method of FIG. 8, and the number of electrode portions is “6”. Therefore, the number of connecting portions is 6-1 = 5 and becomes “5”. The take-out angle is 360/5 = 72, which is twice 144, and 144 degrees. The superposition angle is n = 5, 72/2 × 5 = 180 and 180 degrees.

[Second Embodiment]
[Description of Second Embodiment: FIGS. 14 to 16]
Next, the formation method of the electrode group 40b of the flat battery 4 in 2nd Embodiment is demonstrated using FIGS. 14-16. FIG. 14A to FIG. 16E are plan views showing steps of an electrode group forming process by ninety-nine folds of the positive electrode plate 41b and the negative electrode plate 43b of the electrode group 40b in the second embodiment.

  The feature of the electrode group 40b in the second embodiment is that the extraction angle between the connecting portions is different from that of the electrode group 40 in the first embodiment. That is, in the electrode group 40 in the first embodiment, the take-out angle between the connecting portions is determined based on the design method of FIG. 8 and is one type, but the electrode group 40b in the second embodiment is designed in the design of FIG. Without adopting the method, there are two types of take-off angles between the connecting portions. In the present embodiment, the number of the positive electrode portions and the number of the negative electrode portions are five, and the connecting portion employs four electrode plates. Of the five electrode portions, the electrode portion located at the end portion has a connecting portion take-out angle θ5 of 90 degrees, and the other take-out angle take-out angle θ4 is 180 degrees. Other structures, elements, and processes are the same as those in the first embodiment.

  First, as shown in FIG. 14 (a), the connecting portion 411bt of the positive electrode plate 41b and the connecting portion 431bt of the negative electrode plate 43b are arranged so as to be shifted by 45 degrees in a plane, and as shown in FIG. The positive electrode part 411b of the plate 41b is overlaid on the negative electrode part 431b of the negative electrode plate 43b.

  Next, as shown in FIG. 14B, a fold line B1 is defined which intersects the connecting portion 431bt of the negative electrode plate 43b at a right angle. Then, the negative electrode plate 43b is folded in the direction of the arrow F1 with the fold line B1 as a valley. Thereby, the negative electrode part 432b of the negative electrode plate 43b overlaps with the positive electrode part 411b of the positive electrode plate 41b.

  As shown in FIGS. 15A to 16E, the same process is further repeated, and the positive electrode plate 41b and the negative electrode plate 43b are arranged in the direction of F2 with B2 as a valley in FIG. 15A. In FIG. 15 (b), B3 is a valley and in the direction of F3. In FIG. 15 (c), B4 is a valley and in the direction of F4. In FIG. 16 (a), B5 is a valley and in the direction of F5. ) In the direction of F6 with B6 as a valley, in FIG. 16 (c) with B7 as a valley in the direction of F7, in FIG. 16 (d) with B8 as a valley and in the direction of F8 As a result, the electrode group 40b having the positive electrode portion 415b as the uppermost layer is completed as shown in FIG. In the plan view of the electrode group 40b as viewed from above, the connecting portions 411bt to 414bt and the connecting portions 431bt to 434bt are arranged so as not to overlap from the midpoint of each side of the electrode group 40b.

  The electrode group 40b completed by the above steps is assembled into a battery case to complete a flat battery, but the description of the incorporation process is omitted because it is the same as in the first embodiment.

[Third embodiment]
In the third embodiment, strip-like electrodes connected by opposing sides having a fixed length are used, and the connecting portions are provided by being shifted in the width direction of the opposing sides. In the embodiment, each of the positive electrode portion and the negative electrode portion is six pieces (five connecting portions), the shape of the positive electrode portion and the negative electrode portion is a rectangle, and each side is divided into five equal parts. Each electrode part is connected by five connection parts protruding from the side. In addition, the space | interval between these connection parts is not limited equally, You may determine a space | interval as needed.

[Explanation of Third Embodiment: FIGS. 17 to 19]
Next, a method for forming the electrode group 40c of the flat battery 5 according to the third embodiment will be described with reference to FIGS. FIG. 17A to FIG. 19D are plan views showing a process of forming an electrode group by ninety-nine folds of the positive electrode plate 41c and the negative electrode plate 43c of the electrode group 40c in the third embodiment.

  The characteristics of the electrode group 40c in the third embodiment are that the shape of the positive electrode plate 41c and the negative electrode plate 43c in the plan view is square compared to the electrode group 40 in the first embodiment, and that the positive electrode plate 41c and the negative electrode plate 43c The take-off angle θ6 between the connecting portions is 180 degrees, and the take-out position of each connecting portion is shifted between the opposing sides of the positive electrode plate 41c and the negative electrode plate 43c.

  More specifically, the connecting portions 411ct to 415ct (412ct to 414ct are not shown) and the connecting portions 431ct to 435ct (432ct to 434ct are not shown) of the positive electrode plate 41c and the negative electrode plate 43c in the third embodiment. As shown in FIG. 17A, the connecting portions are shifted in the width direction of the opposing sides of the positive electrode plate 41c and the negative electrode plate 43c.

  First, as shown in FIG. 17A, the connecting portion 411ct of the positive electrode plate 41c and the connecting portion 431ct of the negative electrode plate 43b are arranged so as to be shifted by 90 degrees in a plane, and is placed on the positive electrode portion 411c of the positive electrode plate 41c. The negative electrode part 431c of the negative electrode plate 43c is overlapped.

  Next, as shown in FIG. 17B, a fold line B1 that intersects the connecting portion 411ct of the positive electrode plate 41c at a right angle is defined. Then, the positive electrode plate 41c is folded in the direction of the arrow F1 with the fold line B1 as a valley. As a result, the positive electrode portion 412c of the positive electrode plate 41c overlaps the negative electrode portion 431c of the negative electrode plate 43c.

  The subsequent steps are the same as in the first embodiment. That is, as shown in FIGS. 17 (c) to 19 (c), the positive electrode plate 41c and the negative electrode plate 43c are arranged in the direction F2 with B2 as a valley in FIG. 17 (c), and B3 in FIG. 18 (a). In the direction of F3 as a valley, in FIG. 18 (b), B4 is a valley and in the direction of F4, in FIG. 18 (c), B5 is a valley and in the direction of F5, and in FIG. 18 (d), B6 is a valley. In the direction of F6, in FIG. 18 (e), B7 is a valley and in the direction of F7, in FIG. 19 (a), B8 is a valley and in the direction of F8, and in FIG. 19 (b), B9 is a valley. In FIG. 19 (c), B10 is a trough in the direction of F9, and is wound up in turn in the direction of F10 by ninety-nine folds. Finally, as shown in FIG. 19 (d), the negative electrode portion 436c is formed on the uppermost layer. The provided electrode group 40c is completed. The connection parts 411 bt to 414 bt and the connection parts 431 bt to 434 bt are arranged so as not to overlap at positions shifted in the width direction of the opposite side from the four sides of the square of the electrode group 40 c in a plan view when the electrode group 40 c is viewed from above. .

  The flat electrode battery is completed by incorporating the electrode group 40c completed by the above steps into the battery case, but the description of the incorporation process is omitted because it is the same as in the first embodiment.

It is needless to say that the embodiment described above is an embodiment, and is not limited thereto, and can be arbitrarily changed as long as it satisfies the gist of the present invention.
For example, the take-off angle between the connecting portions is obtained by dividing the circumferential angle (360 degrees) surrounding the electrode portion by the number of connecting portions in the electrode portion based on the design method described in FIG. A method of selecting from an angle in a range larger than 60 ° and smaller than 180 ° is basic, but depending on the connecting portion length L shown in FIG. 3C and FIG. It may be feasible even if it is smaller than °.
Further, the shape of the electrode portions on the positive electrode side and the negative electrode side may be other polygons or circles instead of the quadrangle to the ten-gon. In addition, the number of the electrode portions on the positive electrode side and the negative electrode side of the electrode group formed by stacking the ninety-nine folds can be arbitrarily increased or decreased.
In the embodiment of the present invention, each connecting portion is in the form of an elongated strip, but it is also possible to increase the coupling strength with the connecting portion by arcing the connecting portion with the electrode portion.

DESCRIPTION OF SYMBOLS 1 Flat type battery 10 Exterior case 15 Battery case 20 Gasket 30 Sealing case 40, 40p, 40q, 40b, 40c Electrode group 41, 41p, 41q, 41b, 41c Positive electrode plate 41k (positive electrode side) Active material layer 41m Positive electrode foil 411 ˜415, 411p˜415p, 411q˜415q, 411b˜415b, 411c˜415c, positive electrode part (electrode part)
411t to 415t, 411pt to 415pt, 411qt to 415qt, 411bt to 415bt, 411ct to 415ct (positive electrode side) connecting portion 43, 43p, 43q, 43b, 43c negative electrode plate 43k (negative electrode side) active material layer 43m negative electrode foil 431 ~ 435, 431p ~ 435p, 431q ~ 435q, 431b ~ 435b, 431c ~ 435c Negative electrode part (electrode part)
431t to 435t, 431pt to 435pt, 431qt to 435qt, 431bt to 435bt, 431ct to 435ct (negative electrode side) connecting portion θ1 to θ6 take-out angle L connecting portion length F1 to F10 folding direction B1 to B10 folding line 100 electrode body 102 positive electrode DESCRIPTION OF SYMBOLS 103 Negative electrode 104 Separator 105 Electrode body layer 1051-1054 Edge of folding part 105a Swelling part 106 Gap ST1 Battery specification specification setting process ST2 Number of electrode parts setting process ST3 Total number of connecting parts ST4 Angle setting process between connecting parts ST5 Nine Ninefold folding angle setting process

Claims (2)

In a flat battery in which an electrode group is formed by folding a positive electrode plate and a negative electrode plate each having an active material layer formed on a surface thereof, and the positive electrode plate and the negative electrode plate are opposed to each other,
The positive electrode plate and the negative electrode plate have a plurality of electrode portions having the same shape, and a plurality of connecting portions that connect the adjacent electrode portions,
When the electrode group is formed by folding at each of the connection portions, the connection portions are arranged at positions where they do not overlap with each other in a plan view when the electrode group is viewed from above. Flat battery. The flat battery according to claim 1, wherein the positive electrode plate and the negative electrode plate are folded by ninety-nine folds.

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