Battery manufacture method

Abstract

To provide a battery that can be safely deformed, provide a battery that can be bent and has a large thickness, and provide a battery with an increased capacity.SOLUTION: A wavy film that is periodically continuous in one direction is used for the exterior body of a battery. A space is provided inside the exterior body between the unfixed end of an electrode stack and the inner wall of the exterior body. Furthermore, the waves of a pair of parts of the exterior body that sandwich the electrode stack are formed to be out of phase. In particular, the waves are formed to be out of phase by 180 degrees such that the ridge lines overlap and the valley lines overlap.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to a battery. One aspect of the present invention relates to a bendable battery. One aspect of the present invention relates to an exterior body for a battery.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a power storage device, a storage device, and a , electronic device, lighting device, input device, input / output device, driving method thereof, or manufacturing method thereof The law can be cited as one example. [Background technology]

[0003] In recent years, mobile information terminals such as smartphones have been actively developed. Users expect portable information terminals, which are a type of electronic device, to be lightweight and small. In addition, development of wearable devices that are attached to the user is also underway.

[0004] Equipment such as wearable devices and mobile information terminals are capable of repeated charging and discharging. They often have secondary batteries installed. In addition, such devices are required to be lightweight and compact. However, the capacity of the secondary battery is small, and the operating time is limited. As a secondary battery to be installed in such equipment, it is lightweight, small, and can be used for a long time. It is required that.

[0005] Patent Document 1 describes a highly flexible device that uses a thin, flexible film-like material as an exterior body. A battery is disclosed. [Prior art documents] [Patent documents]

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when a flexible battery is fabricated using the technology disclosed in Patent Document 1, if the battery is not thin (for example, 400 μm or less in thickness), the exterior body may be damaged when the battery is bent. On the other hand, such a thin battery has a problem in that sufficient capacity cannot be obtained.

[0008] One aspect of the present invention aims to provide a battery that can be safely deformed. Or, one aspect of the present invention aims to provide a battery that can be bent and has a greater thickness. Or, one aspect of the present invention aims to provide a battery with increased capacity. Or, one aspect of the present invention aims to provide a battery with high reliability. Or, one aspect of the present invention aims to manufacture a battery at

[0009] low cost. Note that the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily need to solve all of these problems. Also, it is possible to extract problems other than those described above from the description in the

[0010] One aspect of the present invention is a battery having a laminate and an exterior body. The exterior body has a film-like shape and is bent into two parts so as to sandwich the laminate. It has a first part, a second part, a pair of third parts, and a fourth part. The pair of first parts overlap each other and are the parts surrounded by the second part, the third parts, and the fourth part, and include the parts overlapping with the laminate. The second part is located between the pair of first parts, and is a bent part. The pair of third parts are located opposite to each other so as to sandwich the first part and are strip-shaped parts extending in a direction intersecting with the second part. The fourth part is a strip-shaped part located on the opposite side of the second part with the first part sandwiched therebetween. Further, the exterior body is joined at the third part and the fourth part, and inside the exterior body, there is a space between the laminate and the second part without the laminate and the second part being in contact.

[0011] Also, in a plan view of the exterior body, it is preferable that the length in the extending direction of the third part is longer than the length in the direction parallel to the direction passing through the first part, the second part and the fourth part.

[0012] Also, the first part preferably has a wavy shape in which a plurality of ridge lines and a plurality of valley lines parallel to each other are alternately positioned, and the third part is preferably flat.

[0013] Also, it is preferable that the first part has a region where the wave period becomes longer and the amplitude becomes smaller as it gets closer to the second part.

[0014] The exterior body preferably has a region where the ridge line of one of the pair of first parts does not coincide with the valley line of the other first part. In particular, it is preferable that the pair of first parts each have a region where their respective ridge lines overlap and their respective valley lines overlap.

[0015] Also, it is preferable that the second part does not have a wavy shape.

[0016] Also, it is preferable that one ridge line is located between the valley line located closest to the second part side of the first part and the second part.

[0017] Also, in a state where the battery is not bent, the distance between the end on the second part side of the laminate inside the exterior body and the inner surface of the exterior body is preferably π×t or more when the thickness of the laminate is 2t.

[0018] Also, one aspect of the present invention is a method for manufacturing a battery having a laminate inside an exterior body, which includes the following first to third steps. The first step is a step of preparing a film-shaped exterior body processed in a wave shape in which a plurality of ridge lines and a plurality of valley lines parallel to each other are alternately located and the plurality of ridge lines are equally spaced. The second step is a step of folding a part of the exterior body 180 degrees in a direction perpendicular to the ridge lines and the valley lines to sandwich the laminate. The third step is a step of joining another part of the exterior body, which is located outside the laminate and extends in a direction perpendicular to the ridge lines and the valley lines, in a band shape. In the third step, the exterior body is joined so that a part of the exterior body becomes flat, and in a part where the exterior body overlaps with the laminate, the exterior body is joined so that the interval between the plurality of ridge lines widens as it gets closer to the bent part of the exterior body.

[0019]

[0020] ​​​​​​​​​​​​​​​Also, in the second step, it is preferable to shift and bend the outer package so that the ridge lines and valley lines of the folded and overlapping outer packages do not overlap. In particular, in the second step, it is preferable to bend the outer package so that the ridge lines of the folded and overlapping outer packages overlap each other and the valley lines overlap each other.

Advantages of the Invention

[0021] According to one aspect of the present invention, it is possible to provide a battery that can be safely deformed. Or, it is possible to provide a battery that can be bent and has an increased thickness. Or, it is possible to provide a battery with increased capacity. Or, it is possible to provide a battery with high reliability. Or, it is possible to manufacture a battery at low cost.

[0022] Note that one aspect of the present invention does not necessarily have all of these effects. It is possible to extract other effects from the descriptions in the detailed description, drawings, claims, etc.

Brief Description of the Drawings

[0023]

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[0024] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art can easily understand that the form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being

[0025] limited to the content described in the following embodiments. In the configuration of the invention described below, the same parts or parts having the same functions are commonly used with the same reference numerals among different drawings, and the

[0026] repeated description thereof is omitted. Also, when referring to the same function, the hatch patterns may be the same, and there may be cases where no specific reference numerals are given.

[0027] In each drawing described in this specification, the size of each component, the thickness of each layer, or the area may be exaggerated for clarity. Therefore, it is not necessarily

[0028] (Embodiment 1) In this embodiment, a configuration example and a manufacturing method example of a battery according to an aspect of the present invention will be described. .

[0029] One aspect of the present invention is a battery that can be bent. A wavy film that is periodically continuous in one direction is used for the exterior body of the battery. By forming the exterior body into a wavy shape, the stress generated when the exterior body is bent is relaxed by deforming so that the period and amplitude of the waves change, preventing the exterior body from being damaged. When the exterior body is bent, the stress generated is relaxed by deforming so that the period and amplitude of the waves change, preventing the exterior body from being damaged. When the exterior body is bent, the stress generated is relaxed by deforming so that the period and amplitude of the waves change, preventing the exterior body from being damaged. When the exterior body is bent, the stress generated is relaxed by deforming so that the period and amplitude of the waves change, preventing the exterior body from being damaged.

[0030] The electrode laminate of the battery according to one aspect of the present invention is characterized in that a part to which a tab or the like is connected is fixed, and the electrodes are relatively displaced from each other in other parts. When the exterior body of the battery is bent, the electrode laminate can be deformed so that each part is relatively displaced with the fixed point as a fulcrum. When the exterior body of the battery is bent, the electrode laminate can be deformed so that each part is relatively displaced with the fixed point as a fulcrum. When the exterior body of the battery is bent, the electrode laminate can be deformed so that each part is relatively displaced with the fixed point as a fulcrum. When the exterior body of the battery is bent, the electrode laminate can be deformed so that each part is relatively displaced with the fixed point as a fulcrum.

[0031] Furthermore, one aspect of the present invention has a space between the unfixed end of the electrode laminate and the inner wall of the exterior body inside the exterior body. This space can prevent the electrode laminate from being displaced and coming into contact with the inner wall of the exterior body when the battery is bent. One aspect of the present invention can prevent the exterior body from being damaged due to contact with the exterior body accompanying the deformation of the electrode laminate, regardless of the thickness of the electrode laminate. For example, even when the thickness of the battery is greater than 400 μm, or 500 μm or more, or 1 mm or more, it is possible to repeatedly deform safely, such as bending and stretching. Of course, it can also be applied to extremely thin batteries of 1 μm or more and 400 μm or less. This space can prevent the electrode laminate from being displaced and coming into contact with the inner wall of the exterior body when the battery is bent. This space can prevent the electrode laminate from being displaced and coming into contact with the inner wall of the exterior body when the battery is bent. This space can prevent the electrode laminate from being displaced and coming into contact with the inner wall of the exterior body when the battery is bent. One aspect of the present invention can prevent the exterior body from being damaged due to contact with the exterior body accompanying the deformation of the electrode laminate, regardless of the thickness of the electrode laminate. For example, even when the thickness of the battery is greater than 400 μm, or 500 μm or more, or 1 mm or more, it is possible to repeatedly deform safely, such as bending and stretching. Of course, it can also be applied to extremely thin batteries of 1 μm or more and 400 μm or less. This space can prevent the electrode laminate from being displaced and coming into contact with the inner wall of the exterior body when the battery is bent. One aspect of the present invention can prevent the exterior body from being damaged due to contact with the exterior body accompanying the deformation of the electrode laminate, regardless of the thickness of the electrode laminate. For example, even when the thickness of the battery is greater than 400 μm, or 500 μm or more, or 1 mm or more, it is possible to repeatedly deform safely, such as bending and stretching. Of course, it can also be applied to extremely thin batteries of 1 μm or more and 400 μm or less.

[0032] There is no limit to the thickness of the battery, but it depends on the required capacity of the electronic device in which the battery is incorporated and the shape of the device. The thickness may be selected according to the application, such as the shape of the material, etc. For example, the thickness may be set to 10 mm or less, preferably 5 mm or less. m or less, more preferably 4 mm or less, and even more preferably 3 mm or less.

[0033] In order to form a larger space between the inner wall of the exterior body, the outer wall sandwiching the electrode laminate is It is preferable that the waves of the pair of portions of the housing are out of phase with each other. Of a pair of exterior body parts located on either side of each other, the ridge line of one part and the valley line of the other part It is preferable that the electrodes are formed so as to be offset from each other so as not to overlap each other. In the portion of the pair of exterior bodies sandwiching the laminate, the ridge lines overlap each other and the valley lines overlap each other. When the phases are shifted by 180 degrees, the distance between the electrode laminate and the exterior body is the shortest. This is preferable because it allows the formation of a long space. If the valleys of the parts are formed so that they overlap and are in phase, the shape of the space that is formed The shape of the electrode laminate becomes irregular, and the distance between the electrode laminate and the exterior body becomes the smallest. Therefore, this is not desirable.

[0034] In one embodiment of the present invention, for example, a film is folded in half in a direction parallel to the ridges and valleys of the waves. The electrode laminate is sandwiched between two pieces of paper and pressed so that at least two sides perpendicular to the folded portion are flat. The film can be made by bonding it while applying heat. The film is folded so that the waves on the opposing films are at least slightly out of phase with each other. It is particularly preferable to fold the film so that the waves are out of phase with each other by 180 degrees. stomach.

[0035] Here, the phase of the waves of a pair of parts of the exterior body facing each other with the electrode laminate in between changes from before bonding to after bonding. There may also be a deviation after that. Even in such a case, after joining, at least it is preferable that the region adjacent to the bent portion has a portion where the phases of the pair of partial waves do not match.

[0036] With the joining, the two sides sandwiching the electrode laminate become longer than the natural length before joining. As a result, a force is generated in the portion overlapping the electrode laminate to pull it in a direction perpendicular to the ridge line and valley line of the wave. On the other hand, in the portion overlapping the electrode laminate, a resistance force is generated in the opposite direction to the pulling force so as to maintain the wave shape. Since the resistance force becomes weaker the closer it is to the bent portion, the wave of the exterior body deforms so as to stretch closer to the bent portion. Specifically, the exterior body deforms such that the period of the wave becomes larger and the amplitude of the wave becomes smaller the closer it is to the bent portion. By joining in such a way that the joint portion becomes sufficiently flat by such a mechanism, a space can be formed between the bent portion and the electrode laminate.

[0037] In order to form a sufficiently large space between the inner wall of the exterior body and the electrode laminate, the shape of the wave of the film used is important. The smaller the period of the wave of the film and the larger the amplitude, the larger the space that can be formed. For example, when the natural length of the corrugated film is 1, it is preferable to use a film whose length when the film is stretched is 1.02 times or more, preferably 1.05 times or more, more preferably 1.1 times or more and 2 times or less for the exterior body. The shape of the wave can be various shapes such as a sine curve, a triangular wave shape, an arc shape, a rectangular shape, etc., and it may be a shape in which convex portions and concave portions are repeated at least in one direction. ​​​​​​​​​​​​​If the amplitude of the wave is large, the volume of the battery may become large. Therefore, it is preferable to reduce the period of the wave and increase the ratio of the length of the film when stretched to the natural length of the film. Preferably.

[0038] Also, in order to sufficiently form a space, the bonding conditions are also important. If the bonding is insufficient, the bonding part will not be flat but will undulate, and there is a risk that the space will not be sufficiently formed. Also, since the bonding is performed with the phase of the wave shifted, if the bonding is insufficient, there is also a risk that a gap will occur at the bonding part when the battery is deformed. However, if a sufficiently optimized bonding method is used, it can be said that such problems will not occur. The preferable conditions for bonding vary depending on the material of the film and the material of the adhesive used for bonding, etc. For example, when using polypropylene as a heat-sealing layer, a pressure that can flatten the undulated embossed shape can be applied at a temperature above the melting point of polypropylene. Also, compared to the bonding part (top seal) in the direction parallel to the corrugated embossed shape, it is preferable to bond the bonding part (side seal) in the direction orthogonal to the corrugated embossed shape with a higher pressure. Preferably.

[0039] According to one aspect of the present invention, since the shape of the secondary battery can be freely designed, for example, by using a secondary battery having a curved surface, the degree of freedom of the entire electronic device is increased, and an electronic device having various designs can be realized. Also, by providing the secondary battery along the inner surface of the electronic device having a curved surface, the space inside the electronic device can be effectively utilized without creating a wasted space inside the electronic device.

[0040] Furthermore, according to one aspect of the present invention, since it is possible to increase the capacity of the secondary battery, It becomes possible to extend the usable time of the electronic device and reduce the frequency of charging.

[0041] Therefore, an electronic device with a novel structure can be realized.

[0042] Hereinafter, more specific configuration examples and manufacturing method examples will be described with reference to the drawings.

[0043] [Configuration Example] FIG. 1(A) is a plan view of the battery 10 exemplified below. Further, FIG. 1(B) is a view seen from the direction indicated by the arrow in FIG. 1(A ). Further, FIGS. 1(C), (D), and (E) are schematic cross-sectional views when cut along the cutting lines A1-A2, B1-B2, and C1-C2 in FIG. 1(A), respectively. FIG.

[0044] The battery 10 has an exterior body 11, a laminate 12 housed inside the exterior body 11, and electrodes 13a and 13b that are electrically connected to the laminate 12 and extend outside the exterior body 11. Also, an electrolyte is enclosed inside the exterior body 11 in addition to the laminate 12.

[0045] The exterior body 11 has a film-like shape and is bent into two parts so as to sandwich the laminate 12. The exterior body 11 has a pair of portions 31 that sandwich the laminate 12, a bent portion 32, and a pair of joining portions 33 and 34. The pair of joining portions 33 are strip-shaped portions extending in a direction substantially perpendicular to the bent portion 32 and are provided with the portion 31 therebetween. The joining portion 34 is a strip-shaped portion located on the opposite side of the bent portion 32 with the portion 31 therebetween. The portion 31 can also be said to be a region surrounded by the bent portion 32, the pair of joining portions 33, and the joining portion 34. Here, in FIG. 1(A), etc., an example is shown in which the joining portion 34 sandwiches a part of the electrodes 13a and 13b.

[0046] ​​​​​​​​​ The surface of at least the portion 31 of the exterior body 11 has irregularities in the direction in which the pair of joints 33 extend. That is, it has a wavy shape in which ridges 21 and valleys 22 are repeated alternately. In FIG. 1(A) and the like, the ridge line 21 connecting the tops of the convex portions is shown as a dashed line, and the valley line 22 connecting the bottoms of the valley portions is shown as a broken line.

[0047] Also, in plan view, the length of the joints 33 in the extending direction is longer than the length in the direction parallel to the extending direction of the joints 33, passing through the joint 34, the portion 31, and the bent portion 32 of the exterior body 11. As shown in FIG. 1(A), with respect to the line connecting the ends on the bent portion 32 side of the pair of joints 33, the portion of the bent portion 32 closest to the joint 34 is positioned on the joint 34 side by a distance L1.

[0048] The laminate 12 has a configuration in which at least a positive electrode and a negative electrode are alternately laminated. The laminate 12 can also be referred to as an electrode laminate. Also, a separator may be provided between the positive electrode and the negative electrode. Here, the greater the number of laminations of the laminate 12, the greater the capacity of the battery 10 can be increased. Details of the laminate 12 will be described later.

[0049] Here, the thickness of the laminate 12 is preferably, for example, 200 μm or more and 9 mm or less, more preferably 400 μm or more and 3 mm or less, and even more preferably 500 μm or more and 2 mm or less, and typically about 1.5 mm.

[0050] As shown in FIGS. 1(A), (C), and (D), inside the exterior body 11, between the end portion of the laminate 12 closest to the bent portion 32 and the inner surface of the exterior body 11 located at the bent portion 32 ​​​​​​​​​​There is a space 25 (also referred to as a gap or void) in between. Here, the length in the direction parallel to the extending direction of the joint 33 of the space 25 is defined as the distance d0. The distance d0 can also be described as the distance between the end portion on the most bendable portion 32 side of the laminate 12 and the inner surface located at the bend 32 of the exterior body 11. Also, the laminate 12 is joined to the electrodes 13a (and the electrode 13b) that extend inside and outside the exterior body 11 via the joint 34. Therefore, it can be said that the relative positions of the laminate 12 and the exterior body 11 are fixed by the joint 34. The electrode 13a is joined to either one of the plurality of positive electrodes and the plurality of negative electrodes that the laminate 12 has, and the electrode 13b is joined to the other.

[0051]

[0052] Also, as shown in FIGS. 1(A), (C), and (D), the portion 31 of the exterior body 11 preferably has a region where the period of the wave becomes larger and the amplitude of the wave becomes smaller as it gets closer to the bend 32. By manufacturing the battery 10 in such a form, the space 25 provided inside the exterior body 11 can be formed.

[0053] Also, as shown in FIGS. 1(C) and (D), it is most preferable that the pair of portions 31 sandwiching the laminate 12 face each other such that the phase of the wave is shifted by 180 degrees. In other words, it is preferable that the exterior body 11 is bent such that the ridge lines 21 overlap each other and the valley lines 22 overlap each other with the laminate 12 sandwiched therebetween. This can make the shape of the space 25 good.

[0054] [Regarding the space] Subsequently, the shape when the battery 10 in which the space 25 is formed is bent will be described.​​​​​​​​​​​​​​

[0055] Figure 2(A) is a schematic cross-sectional view showing a simplified part of the configuration of the battery 10.

[0056] Here, a pair of portions 31 of the exterior body 11 are distinguished and shown as portion 31a and portion 3 1b, respectively. Similarly, the ridge lines of each portion are denoted as ridge line 21a, ridge line 21 b, and the valley lines are denoted as valley line 22a and valley line 22b for distinction.

[0057] In Figure 2(A), the laminate 12 has a configuration in which five electrodes 43 are laminated. The electrode 4 3 corresponds to the electrode 41 or the electrode 42 in Figure 1(A). Also, the plurality of electrodes 43 are fixed in relative positions at the ends on the side of the joint portion 34. Further, the laminate 12 and the exterior body 11 are fixed in relative positions at the joint portion 34.

[0058] Inside the exterior body 11, a space 25 is provided near the bent portion 32. Here wherein, when the exterior body 11 is not bent, the distance between the end on the bent portion 32 side of the electrode 43 and the inner wall of the exterior body 11 is defined as the distance d0.

[0059] Also, the neutral plane of the battery 10 is defined as the neutral plane C. Here, the neutral plane C is assumed to coincide with the neutral plane of the electrode 43 located at the center among the five electrodes 43 that the laminate 12 has.

[0060] Figure 2(B) is a schematic cross-sectional view when the battery 10 is bent in an arc shape about the point O. Here the battery 10 is bent such that the portion 31a is on the outside and the portion 31b is on the inside.

[0061] As shown in Figure 2(B), the portion 31a located on the outside has a small wave amplitude and the wave ​Deform so that the period becomes larger. That is, the ridge lines 21a of the portion 31a located on the outer side The distance between them and the distance between the valley lines 22a become wider. On the other hand, the portion 31b located on the inner side Deforms so that the amplitude of the wave is large and the period of the wave is small. That is, the ridge lines 21b after bending of the portion 31b located on the inner side The distance between them and the distance between the valley lines 22b after bending Become narrower. By deforming the portion 31a and the portion 31b in this way, the stress applied to the exterior body 1 1 is relaxed, and the battery 10 can be bent without the exterior body 11 being damaged .

[0062] Also, as shown in FIG. 2(B), the laminate 12 deforms so that the plurality of electrodes 43 are displaced relative to each other . As a result, the stress applied to the laminate 12 is relaxed, and the battery 10 can be bent without the laminate 12 being damaged . In FIG. 2(B), each electrode 43 itself Is shown as not stretching by bending. By making the thickness of the electrode 43 sufficiently small with respect to the radius of curvature of bending , the stress applied to each electrode 43 itself can be reduced .

[0063] Among the electrodes 43 included in the laminate 12, the electrodes 43 located outside the neutral plane C The ends thereof are displaced toward the joint portion 34

[0064] On the other hand, the electrodes 43 located inside the neutral plane C The ends thereof are displaced toward the bent portion 32. Here, the distance between the end portion on the bent portion 32 side of the innermost electrode 43 and the inner wall of the exterior body 11 Shrinks from the distance d0 to the distance d1. Here, the relative displacement amount between the electrode 43 located on the neutral plane C and the innermost electrode 43 is defined as the distance d2. The distance d1 And the distance d2 satisfy the relationship: will be equal to the value obtained by subtracting distance d2 from distance d0.

[0065] Here, when the distance d0 in the state before bending is smaller than the distance d2 after bending the electrode 43 located inside the neutral plane C of the laminate 12 will come into contact with the inner wall of the exterior body 11 and this will occur. Therefore, below, we consider how much distance d0 is required.

[0066] Below, we will explain using Fig. 2(C). In Fig. 2(C), the curve corresponding to the neutral plane C is shown by a dashed line, and the curve corresponding to the innermost surface of the laminate 12 is shown by a solid line as curve B .

[0067] Curve C is an arc with a radius r0, and curve B is an arc with a radius r1. Let the difference between the radius r0 and the radius r1 be t. Here, t is equal to half of the thickness of the laminate 12. Also, curves C and B have equal arc lengths respectively. Let the central angle of curve C be θ, and the central angle of curve B be θ + Δθ.

[0068] From the above relationships, calculating the displacement amount d2 of curve B with respect to the end of curve C, which is the distance d2, will be as follows.

[0069]

Equation

[0070] That is, the distance d2 can be estimated by the thickness of the laminate 12 and the bending angle, and it is shown that it does not depend on the length of the laminate 12, the bending radius of curvature, etc.

[0071] As described above, by making the distance d0 in the space 25 larger than or equal to the distance d2, the battery 10 When bent, contact between the laminate 12 and the exterior body 11 can be prevented. Therefore , when using the battery 10 with the laminate 12 having a thickness of 2t by bending it, if the maximum angle is the angle θ , then the distance d0 between the laminate 12 and the inner wall of the exterior body 11 in the space 25 should be a value equal to or greater than t×θ.

[0072] For example, when using the battery by bending it at 30 degrees, the distance d0 of the space 25 should be πt / 6 or more. Similarly, when using it by bending at 60 degrees, d0 should be πt / 3 or more. When using it by bending at 90 degrees, d0 should be πt / 2 or more. When using it by bending at 180 degrees , d0 should be πt or more.

[0073] For example, if it is not used for applications such as winding the battery 10, the maximum bending angle that the battery 10 is assumed to have can be 180 degrees. Therefore, in such applications, if the distance d0 is set to a length of πt or more, preferably a length greater than πt, it can be used in any device. For example, in the case of using the battery 10 by bending it into two, it can be incorporated into various electronic devices that use the battery 10 bent in a V-shape or U-shape.

[0074] Also, for example, when the battery 10 is in a shape wound around a cylinder for one turn, in order to correspond to bending it 360 degrees, the distance d0 of the space 25 should be 2πt or more. Also, when winding it more than one turn, the distance d0 of the space 25 should be set to an appropriate value accordingly. Also, when deforming the battery 10 into a bellows shape, depending on the direction and angle of the bent portion of the battery 10, as well as the number of bent portions, the distance d0 of the space 25 should be set to an appropriate value.

[0075] ​​​​The above is the description of the space 25.

[0076] [Example of manufacturing method] Hereinafter, an example of the manufacturing method of the battery 10 will be described.

[0077] First, prepare a flexible film to be the exterior body 11.

[0078] It is preferable to use a material with high water resistance and gas barrier properties for the film. Note that as the exterior body the film used is preferably a laminated film obtained by laminating a metal film and an insulating film. As the metal film, aluminum, stainless steel, nickel steel, gold, silver, copper, titanium, chromium, iron, tin, tantalum, niobium, molybdenum, zirconium, zinc, etc. , a metal or alloy that becomes a metal foil can be used. Also, as the insulating film, a plastic film made of an organic material, a hybrid material film containing an organic material (such as an organic resin and a fiber) and an inorganic material ( such as ceramic), a single-layer film selected from carbon-containing inorganic films (such as carbon film, graphite film, etc.) or a laminated film formed from a plurality of these can be used. The metal film is easy to perform embossing, and when embossing is performed to form convex portions, the surface area of the film in contact with the outside air increases, so it has excellent heat dissipation effect.

[0079] Subsequently, the flexible film is processed such as by embossing to form the exterior body 11 having a wavy shape.

[0080] The convex and concave portions of the film can be formed by pressing (for example, embossing). The convex and concave portions formed on the film by embossing are used to seal the film structure. A closed space with a variable volume is formed as part of the wall. This closed space can be said to be formed with a bellows structure or a pleated structure when the film is used. Also, the sealing structure using the film has waterproof and dustproof effects. Further, not limited to embossing which is a kind of pressing process, a method of forming a relief on a part of the film may also be used. Also, combinations thereof, for example, embossing and other pressing processes may be performed on a single film. Also, multiple embossing processes may be performed on a single film. The convex portions of the film can be hollow semi-circular, hollow semi-elliptical, hollow polygonal, or hollow irregular shaped. In the case of a hollow polygonal shape, it is preferable to have more corners than a triangle to reduce stress concentration at the corners.

[0081] An example of a perspective schematic view of the exterior body 11 formed in this way is shown in Fig. 3(A). The exterior body 11 has a wavy shape in which a plurality of ridge lines 21 and valley lines 22 are alternately arranged on the surface facing the outside of the battery 10. Here, it is preferable that the adjacent ridge lines 21 and the adjacent valley lines 22 are arranged at equal intervals.

[0082] Subsequently, a part of the exterior body 11 is bent so as to sandwich the previously prepared laminate 12 (Fig. 3(B)). At this time, it is preferable to adjust the length of the exterior body 11 so that the electrode 13 (electrode 13a or electrode 13b) connected to the laminate 12 is exposed to the outside. Also, since the portion of the exterior body 11 that protrudes outside the laminate 12 becomes the later joint portions 33 and 34, the width of the protruding portion is made to be a sufficient length considering the thickness of the laminate 12.

[0083] Subsequently, a part of the exterior body 11 is bent to sandwich the previously prepared laminate 12 (Fig. 3(B)). At this time, it is preferable to adjust the length of the exterior body 11 so that the electrode 13 (electrode 13a or electrode 13b) connected to the laminate 12 is exposed to the outside. Also, since the portion of the exterior body 11 that protrudes outside the laminate 12 becomes the later joint portions 33 and 34, it is preferable to adjust the length of the exterior body 11 so that the electrode 13 (electrode 13a or electrode 13b) connected to the laminate 12 is exposed to the outside. Also, since the portion of the exterior body 11 that protrudes outside the laminate 12 becomes the later joint portions 33 and 34, the width of the protruding portion is made to be a sufficient length considering the thickness of the laminate 12. For this purpose, the width of the protruding portion is made to be a sufficient length considering the thickness of the laminate 12. ​​

[0084] In FIG. 3(B), an example is shown in which a pair of portions 31 sandwiching the laminate 12 are arranged such that the phases of the respective waves are shifted by 180 degrees. That is, in the pair of portions 31, a state is shown in which the exterior body 11 is bent so that the ridge lines 21 overlap each other and the valley lines 22 overlap each other. .

[0085] Here, the position and shape of the bent portion 32 of the exterior body 11 will be described. FIG. 4(A) is a diagram schematically showing a cross section of the exterior body 11. FIGS. 4(B) to ( E) respectively show the cross-sectional shapes of the bent portion 32 when the points P1 to P4 shown in FIG. 4(A) are taken as the bending positions. In the following, in order to describe the case where the exterior body 11 is bent in the direction indicated by the arrow shown in FIG. 4(A), the lower surface corresponds to the outer surface of the battery 10. Therefore, in FIG. 4(A), the portion protruding upward is shown as the valley line 22, and the portion protruding downward is shown as the ridge line 21. In FIGS. 4(B) to (E), a hatching pattern is applied to the region surrounded by the bent portion 32. Here, with the two positions where the periodicity of the waves of the exterior body 11 is disrupted as boundaries, the region sandwiched between these is defined as the bent portion 32. In FIGS. 4(B) to (E) etc., since the shape of the bent portion 32 is exaggeratedly drawn, its perimeter may not be correctly drawn.

[0086]

[0087] Point P1 is a point that coincides with the valley line 22. As shown in FIG. 4(B), when bending at point P1, the bent portion 32 can have a substantially arc-shaped shape. Also, when bending at point P1, the phases of the opposing waves can be shifted by 180 degrees.

[0088] ​​​​​​​​​​​​ Also, point P2 is a point that coincides with the ridge line 21. As shown in FIG. 4(C), when bent at point P2, the bent portion 32 can also have a substantially arc-shaped configuration. Also, by bending at point P2, the phase of the opposing waves can be shifted by 180 degrees.

[0089] Also, point P3 is between the ridge line 21 and the valley line 22 and is a point on the side of the ridge line 21 rather than the midpoint between them. As shown in FIG. 4(D), by deviating from the ridge line 21 or the valley line 22, the shape of the bent portion 32 becomes a distorted shape rather than a vertically symmetric shape. Also, by bending at point P3, it is possible to bend such that none of the ridges, valleys, and ridges and valleys of the opposing waves coincide.

[0090] Point P4 is a point that coincides with the midpoint between the ridge line 21 and the valley line 22. As shown in FIG. 4(E), when bent at point P4, the shape of the bent portion 32 becomes extremely irregular. Specifically, the bent portion 32 is likely to have a shape that protrudes upward or downward. Therefore, on the side opposite to the protruding portion, it is difficult to increase the distance between the laminate 12 and the inner wall of the exterior body 11.

[0091] Here, as a common matter in FIGS. 4(B), (C), and (D), in each case, there is one ridge line 21 between the valley line 22 closest to the bent portion 32 of the portion 31 and the bent portion 32. In particular, in FIG. 4(B), an example is shown where the boundary of the bent portion 32 coincides with the ridge line 21 of the wave. In this way, by bending the exterior body 11 with the ridge line 21 of the two waves or the vicinity thereof as the boundary, in the inside of the bent portion 32 and its vicinity, it expands in the thickness direction. A space can be secured. As described above, when the battery 10 is bent, it is important to increase the distance between the outermost electrode of the laminate and the inner wall of the exterior body 11. Therefore, by adopting such a shape, the distance can be widened. On the other hand, in Fig. 4(E), on the lower surface side, there is no ridge line 21 between the valley line 22 closest to the bent portion 32 of the portion 31 and the bent portion 32. For this reason, it is difficult to form a wide space in the thickness direction in the bent portion 32 and its vicinity. A space can be secured. As described above, when the battery 10 is bent, it is important to increase the distance between the outermost electrode of the laminate and the inner wall of the exterior body 11. Therefore, by adopting such a shape, the distance can be widened.

[0092] On the other hand, in Fig. 4(E), on the lower surface side, there is no ridge line 21 between the valley line 22 closest to the bent portion 32 of the portion 31 and the bent portion 32. For this reason, it is difficult to form a wide space in the thickness direction in the bent portion 32 and its vicinity. Here, it is preferable that the portion of the exterior body 11 that becomes the bent portion 32 has a flat shape without a waveform. For example, as shown in Fig. 5(A), by sandwiching between a mold 51 and a mold 52 with a flat surface and applying pressure, or applying pressure while applying heat, a part of the exterior body 11 can be flattened. A schematic cross-sectional view of the exterior body 11 flattened in this way is shown in Fig. 5(B). Here, a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other.

[0093] Here, it is preferable that the portion of the exterior body 11 that becomes the bent portion 32 has a flat shape without a waveform. For example, as shown in Fig. 5(A), by sandwiching between a mold 51 and a mold 52 with a flat surface and applying pressure, or applying pressure while applying heat, a part of the exterior body 11 can be flattened. A schematic cross-sectional view of the exterior body 11 flattened in this way is shown in Fig. 5(B). Here, a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other. Here, it is preferable that the portion of the exterior body 11 that becomes the bent portion 32 has a flat shape without a waveform. For example, as shown in Fig. 5(A), by sandwiching between a mold 51 and a mold 52 with a flat surface and applying pressure, or applying pressure while applying heat, a part of the exterior body 11 can be flattened. A schematic cross-sectional view of the exterior body 11 flattened in this way is shown in Fig. 5(B). Here, a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other.

[0094] A schematic cross-sectional view of the exterior body 11 flattened in this way is shown in Fig. 5(B). Here, a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other. Here, a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other.

[0095] Fig. 5(C) shows a schematic cross-sectional view when the exterior body 11 is bent with the point P5 at the center of the formed flat portion as the bending position. As shown in Fig. 5(C), by making the flattened exterior body 11 into the bent portion 32, a wider space can be formed than in Fig. 4(B). Fig. 5(C) shows a schematic cross-sectional view when the exterior body 11 is bent with the point P5 at the center of the formed flat portion as the bending position. As shown in Fig. 5(C), by making the flattened exterior body 11 into the bent portion 32, a wider space can be formed than in Fig. 4(B). Fig. 5(C) shows a schematic cross-sectional view when the exterior body 11 is bent with the point P5 at the center of the formed flat portion as the bending position. As shown in Fig. 5(C), by making the flattened exterior body 11 into the bent portion 32, a wider space can be formed than in Fig. 4(B).

[0096] Figs. 5(D) and 5(E) show examples when the flattening is performed over a wider range than in Fig. 5(C). Here too, similar to Fig. 5(B), a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other. Figs. 5(D) and 5(E) show examples when the flattening is performed over a wider range than in Fig. 5(C). Here too, similar to Fig. 5(B), a part of the exterior body 11 is flattened so as to connect the ridge lines 21 to each other. One part is flattened. In this way, by flattening the exterior body 11 over a range wider than the thickness of the laminate 12, a thick and uniform space in the thickness direction can be formed. This is the explanation of the relationship between the position of the bent part and the shape of the bent part.

[0097] This is the explanation of the relationship between the position of the bent part and the shape of the bent part.

[0098] After bending the exterior body 11 to sandwich the laminate 12 as described above, the parts that will become the joint part 33 of the exterior body 11 are joined by applying pressure while applying heat. This is the explanation of the relationship between the position of the bent part and the shape of the bent part.

[0099] As shown in Fig. 6(A), the crimping can be performed by sandwiching the exterior body 11 between a pair of dies 53 and 54 with flat surfaces. And by crimping in a direction perpendicular to the surfaces of the dies 53 and 54, as shown in Fig. 6(B), the parts that will become the joint part 33 of the exterior body 11 can be joined to be flat. At this time, it is preferable to provide a clearance so that the dies 53 and 54 do not approach each other beyond a certain degree. This can avoid problems such as the thickness of the joint part becoming thinner than a certain level, the conductive material (such as aluminum foil) contained in the film being exposed, and the insulation being broken or reduced. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part.

[0100] To make the joint part 33 sufficiently flat, for example, it is preferable to perform crimping under a pressure higher than the pressure for forming the subsequent joint part 34. The pressure varies depending on the material and thickness of the exterior body. For example, when using a film with a thickness of about 110 μm, the pressure during crimping is in the range of 100 kPa / cm or more and 1000 kPa / cm or less, and typically about 600 kPa / cm. Also, the temperature should be set to be equal to or higher than the melting point of the material used as the fusion layer. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. This is the explanation of the relationship between the position of the bent part and the shape of the bent part. Pa / cm 2 1000 kPa / cm 2 This is the explanation of the relationship between the position of the bent part and the shape of the bent part. m 2 This is the explanation of the relationship between the position of the bent part and the shape of the bent part. It is preferably about 175 degrees, for example, when using polypropylene.

[0101] Also, it is preferable to form the thickness of the joint portion 33 after pressure bonding to be thinner than the thickness of two sheets of the exterior body 11 before pressure bonding. For example, when using a laminated film including a fusion layer for the exterior body, the thickness of the fusion layer of the joint portion 33 after pressure bonding is compared to the thickness of the fusion layer of two sheets of the portion where the exterior body 11 is not pressure bonded (such as the portion 31 of the battery 10 or the bent portion 32, etc.), it is preferably 30% or more and 95% or less, more preferably 50% or more and 90% or less, still more preferably 60% or more and 8 0% or less. By forming the joint portion 33 under the above-described conditions, even when repeated deformation such as bending is applied to the battery 10, the seal is not broken, and leakage of the electrolyte sealed inside the exterior body 11 can also be prevented,

[0102] and a highly reliable and safe battery 10 can be obtained. In particular, as shown in FIG. 6(A), even when the phase of the waves of the opposing portions of the exterior body 11 is shifted by 1 80 degrees and the battery 10 is deformed, a joint portion 33 without a gap can be formed. In FIG. 6(C), the forces applied to each part of the exterior body 11 during joining are schematically shown by arrows. Here, the larger the force, the longer the arrow is shown. Before joining, a part of the exterior body 11 that was wave-shaped becomes flat due to joining, and extends in its stretching direction (the direction indicated by the thick arrow). Along with this extension, a pulling force is generated on the portion 3

[0103] 1 of the exterior body 11 toward the bent portion 32 side. This force is greater the closer it is to the joint portion 33.

[0104] As a part of the exterior body 11 that was wave-shaped before joining becomes flat due to joining, it extends in its stretching direction (the direction indicated by the thick arrow). Along with this extension, a pulling force is generated on the portion 3 1 of the exterior body 11 toward the bent portion 32 side. This force is greater the closer it is to the joint portion 33. 1 of the exterior body 11 toward the bent portion 32 side. This force is greater the closer it is to the joint portion 33. ​​It becomes smaller as it moves away from the joint 33.

[0105] On the other hand, since the portion 31 has a wavy shape, a resistance force is generated in the opposite direction against the above-described force. This resistance force increases as it moves away from the bent portion 32 and decreases as it approaches the bent portion 32. It becomes smaller.

[0106] As a result of the above two types of forces acting on the portion 31 and the bent portion 32, as shown in FIG. 6(D), the period of the wave of the portion 31 continuously increases as it approaches the bent portion 32. It extends so as to become larger. Also, the amount of extension is larger as it approaches the joint 33 and smaller as it moves away from the joint 33. Therefore, the central portion of the bent portion 32 is recessed toward the portion 31 side. It becomes a shape. It becomes. It becomes.

[0107] FIG. 6(E) and FIG. 6(F) are schematic cross-sectional views before and after forming the joint 33, respectively. As shown in FIG. 6(E), even when the laminate 12 is in contact with the inner wall of the outer package 11 before joining, when the portion 31 of the outer package 11 extends during the formation of the joint 33, the space 25 can be formed as shown in FIG. 6(F). It can be formed. It can be formed.

[0108] As described above, by forming the flat joint 33, the space 25 can be formed between the bent portion 32 and the laminate 12. It can be formed.

[0109] Subsequently, an electrolytic solution is introduced from the portion that becomes the joint 34. The electrolytic solution is dropped inside the bag-shaped outer package 11 in a desired amount under reduced pressure or in an inert gas atmosphere. It is dropped.

[0110] Thereafter, the portion that becomes the joint 34 is joined by the same method as described above, and the joint is made. The joint portion 34 is formed. When forming the joint portion 34, between the electrode 13a and the electrode 13b and the exterior body 11 an insulating sealing layer may be disposed. The sealing layer melts during crimping and fixes the space between the electrode 13a and the electrode 13b and the film-like exterior body 11.

[0111] As described above, the battery 10 shown in FIG. 1(A) etc. can be manufactured.

[0112] The above is the explanation about the example of the manufacturing method of the battery.

[0113] [Regarding the shape of the battery] As described above, the space 25 can be formed as a part of the exterior body 11 extends during the formation of the joint portion 33. That is, the distance d0 between the laminate 12 and the exterior body 11 in the space 25 changes according to the amount of elongation at the joint portion 33 of the exterior body 11. To increase the distance d0, it is preferable to use a film such that the ratio of the length when the film is stretched to the natural length of the corrugated film is the above value as the film used for the exterior body 11.

[0114] Also, in the portion 31, the amount of elongation decreases as the distance from the joint portion 33 increases, so the distance d0 decreases. On the other hand, as the amount of elongation of the joint portion 33 increases, the force to stretch the portion 31 increases, so the distance d0 can be increased even at a position away from the joint portion 33. Here, the amount of elongation of the joint portion 33 increases in proportion to the length in the stretching direction of the joint portion 33 when the same film is used.

[0115] FIG. 7 shows a schematic top view of a battery 10 with an aspect ratio different from that of FIG. 1. In the battery 10, the length in the stretching direction of the joint portion 33 is X, and the distance between a pair of joint portions 33 (that is, the width of the portion 31) ​​​​​​​​​​When is taken as Y1, it is preferable to design such that the ratio of X to Y1 (that is, the value of X / Y1) is 1 or more. For example, the ratio of X to Y1 (X / Y1) may be 1.2 or more, 1.5 or more, 1.7 or more, 2 or more, or 3 or more. Also, the ratio of X to Y1 can be as large as possible, but considering productivity, for example, it is preferably less than 100, or less than 50.

[0116] Also, when the width including the joint portion 33 of the battery 10 is taken as Y2, if the ratio of X to Y2 (X / Y 2) is a ratio such as 4 / 3 or 16 / 9, for example, the design of the electronic device incorporating the battery 10 becomes easy, and the versatility of the battery 10 is enhanced, which is preferable. Or, when incorporated into a slender object such as the band of a watch etc., the ratio of X to Y2 (X / Y2) can be 1.5 or more, or 2 or more, or 3 or more, etc.

[0117] The above is the description of the shape of the battery.

[0118] [Regarding the processing method of the film] Next, the processing method of the film that can be used for the exterior body 11 will be described.

[0119] First, prepare a sheet made of a flexible substrate. The sheet uses a laminate and has a heat-sealing layer on one or both surfaces of a metal film . The heat-sealing layer uses a heat-fusible resin film containing polypropylene or polyethylene, etc. In the present embodiment , as the sheet, a metal sheet having nylon resin on the surface of an aluminum foil and provided with a laminate of an acid-resistant polypropylene film and a polypropylene film on the back surface of the aluminum foil is used. Use a sheet. By cutting this sheet, a film of a desired size is prepared.

[0120] Then, embossing is performed on this film. As a result, a film with uneven shapes can be produced. The film has a visible wavy pattern by having a plurality of uneven portions. Also, here, an example of performing embossing after cutting the sheet is shown. However, the order is not particularly limited, and embossing may be performed before cutting the sheet and then cutting it. Alternatively, it may be cut after folding the sheet and performing thermocompression bonding.

[0121] The following explains embossing, which is a type of pressing process.

[0122] FIG. 8 is a cross-sectional view showing an example of embossing. Note that embossing refers to a process of pressing an embossing roll with uneven surfaces on the film to form unevenness corresponding to the unevenness of the embossing roll on the film. The embossing roll is a roll with a pattern engraved on its surface.

[0123] Also, FIG. 8 is an example of performing embossing on both sides of the film. It is also a method for forming a film having convex portions with tops on one surface side.

[0124] FIG. 8 shows that the film 50 is sandwiched between an embossing roll 55 in contact with one surface of the film and an embossing roll 56 in contact with the other surface, and the film 50 is being sent out in the film traveling direction 60. A pattern is being formed on the film surface by pressure or heat. Note that the pattern may be formed on the film surface by both pressure and heat.

[0125] The embossing roll can be appropriately selected from a metal roll, a ceramic roll, a plastic roll, a rubber roll, an organic resin roll, a wood roll, etc.

[0126] FIG. 8 shows embossing using an embossing roll 56 with male patterns and an embossing roll 55 with female patterns. The embossing roll 56 with male patterns has a plurality of convex portions 56a. These convex portions correspond to the convex portions to be formed on the film to be processed. The embossing roll 55 with female patterns has a plurality of convex portions 55a. The adjacent convex portions 55a form concave portions into which the convex portions 56a provided on the embossing roll 56 with male patterns are fitted.

[0127] By continuously performing embossing to lift a part of the film 50 and vacuum pressing to depress a part of the film 50, convex portions and flat portions can be continuously formed. As a result, a pattern can be formed on the film 50.

[0128] Next, a method of forming a film having a plurality of convex portions by a method different from that in FIG. 8 will be described with reference to FIG. 9. FIG. 9 shows an example of performing embossing on one surface of a film. It is also a method of forming a film having convex portions with tops on one surface side.

[0129] FIG. 9(A) shows a state where the film 50 is sandwiched between an embossing roll 55 in contact with one surface of the film and a roll 57 in contact with the other surface, and the film 50 is being fed out in the film advancing direction 60. Note that the roll 57 may be fixed without rotating. Here, since the embossing roll 55 is provided only on one surface of the film, a plurality of convex portions are provided on the film, but the convex portions do not have a space. That is, they protrude on one surface and are flush with the other surface. ​ It is flat at

[0130] Next, as shown in FIG. 9(B), a frame having a convex portion formed on one side by embossing is formed. A part of the film 61 is removed. In this case, the protruding portion is in contact with the flat surface, i.e., the roll 57. The film is then partially removed from the surface that has been exposed to the laser. Thermal removal by irradiation of light, chemical removal by dripping etching solution, physical removal by tool There are also other options.

[0131] As a result, as shown in FIG. 9(C), a space 64 can be formed in the protrusion 63. In addition, a film 62 having protrusions 63 can be formed.

[0132] In the method for producing the film shown in each diagram of FIG. 9, a metal film is used as the film 50. Next, after the steps shown in FIG. 9(A) to FIG. 9(C), It is preferred that the film be provided with a heat seal layer on one or both sides.

[0133] As described above, by performing processing using an embossing roll, the processing device can be made smaller. In addition, since the film can be processed without being cut, it is suitable for mass production. In addition, the processing is not limited to the processing using an embossing roll, but may be, for example, a pair of embossing rolls having uneven surfaces. The film may be textured by pressing an embossing plate against the film. In this case, one of the embossing plates may be flat, and processing may be performed in a plurality of steps.

[0134] [Example of how to make a secondary battery] An example of a method for producing the battery 10, particularly a secondary battery, will be described below. Do so. Note that the description may be omitted for points overlapping with the above.

[0135] Here, a film-like exterior body 11 having a corrugated shape is bent at the center and the two ends are overlapped. A method of sealing three sides with an adhesive layer is used.

[0136] The exterior body 11 including the corrugated film is bent into the state shown in Fig. 10(A). .

[0137] Further, as shown in Fig. 10(B), a laminate of a positive current collector 72, a separator 73, and a negative current collector 74 that constitute a secondary battery is prepared. Although not shown, a positive electrode active material layer is formed on a part of the surface of the positive current collector 72. Also, a negative electrode active material layer is formed on a part of the surface of the negative current collector 74. As the current collectors such as the positive current collector 72 and the negative current collector 74, metals such as stainless steel, gold, platinum, zinc, iron, nickel, copper, aluminum, titanium, tantalum, etc., and alloys thereof, which have high conductivity and do not alloy with carrier ions such as lithium ions, can be used. Also, an aluminum alloy added with an element for improving heat resistance such as silicon, titanium, neodymium, scandium, and molybdenum can be used. Also, it may be formed of a metal element that reacts with silicon to form a silicide. As the metal element that reacts with silicon to form a silicide, there are zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, etc. Also, the current collector may appropriately use shapes such as foil, plate (sheet), net, cylindrical, coil, punched metal, expanded metal, etc. 。It is preferable to use a current collector having a thickness of 5 μm or more and 40 μm or less. Here, for the sake of simplicity of explanation , an example is shown in which a stack combination of a positive electrode current collector 72 formed with a positive electrode active material layer, a separator 73, and a negative electrode current collector 74 formed with a negative electrode active material layer is combined into one and housed in an exterior body However, in order to increase the capacity of the secondary battery, a plurality of combinations are stacked and housed in the exterior body .

[0138] Then, two lead electrodes 76 having a sealing layer 75 shown in FIG. 10(C) are prepared. The lead electrode 76 is also called a lead terminal or a tab, and is provided to draw out the positive electrode or the negative electrode of the secondary battery to the outside of the exterior film . As the lead electrode 76, for example, aluminum is used for the positive electrode lead, and copper plated with nickel is used for the negative electrode lead.

[0139] Then, the positive electrode lead and the protruding portion of the positive electrode current collector 72 are electrically connected by ultrasonic welding or the like . Also, the negative electrode lead and the protruding portion of the negative electrode current collector 74 are electrically connected by ultrasonic welding or the like .

[0140] Then, in order to leave one side for injecting the electrolytic solution, thermocompression bonding is performed on two sides of the film-shaped exterior body 11 using the above-described method to form a bonding portion 33 . Then, a desired amount of electrolytic solution is dropped inside the film-shaped exterior body 11 formed into a bag shape under reduced pressure or in an inert gas atmosphere . Finally, thermocompression bonding is performed on the peripheral edge of the film that has been left without thermocompression bonding to form a bonding portion 34 . During thermocompression bonding, the sealing layer 75 provided on the lead electrode also melts and the lead electrode and the film-shaped exterior body 11 are fixed to each other.

[0141] In this way, the battery 10, which is the secondary battery shown in FIG. 10(D), can be manufactured.

[0142] The film-like exterior body 11 which is the exterior body of the obtained secondary battery 10 has a wavy pattern. In addition, the area between the dotted line and the end in FIG. 10(D) is a joint 33 or a joint Part 34 is machined flat.

[0143] FIG. 10E shows an example of a cross section taken along the dashed line D1-D2 in FIG. 10D. vinegar.

[0144] As shown in FIG. 10(E), a positive electrode current collector 72, a positive electrode active material layer 78, a separator 73, a negative The electrode active material layer 79 and the negative electrode current collector 74 are laminated in this order, and then the laminate is wrapped in a folded film-like exterior. The end of the electrode is sealed by a joint 34. The remaining space is filled with The film-shaped exterior body 11 has an electrolyte 77 filled therein. can be.

[0145] The positive electrode active material used in the positive electrode active material layer 78 may have an olivine type crystal structure or a layered rock salt type There are composite oxides having a crystalline structure or a spinel-type crystalline structure. , such as LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr Compounds such as 2O5 and MnO2 are used.

[0146] Or, a composite material (general formula LiMPO4 (where M is Fe(II), Mn(II), Co( One or more of Ni(II) and Ni(II) can be used. Representative examples of the general formula LiMPO4 Examples include LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, and LiF e a Ni b PO4, LiFe a Co b PO4, LiFea Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4 (a + b is less than or equal to 1, 0 < a < 1, 0 < b < 1), Li Fe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiNi c Co d Mn e P O4 (c + d + e is less than or equal to 1, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h Mn i PO4 (f + g + h + i is less than or equal to 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. Lithium compounds can be used as materials.

[0147] Or, a composite material such as the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co (II), Ni(II), 0 ≤ j ≤ 2) can be used. One General formula Li (2-j) MSiO4 representative examples include Li (2-j) FeSiO4, Li ( 2-j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, L i (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO4, Li (2- j) Fe k Mn l SiO4, Li (2-j) Nik Co l SiO4, Li (2-j) Ni k Mn l SiO4 (k + l is 1 or less, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) N i m Co n Mn q SiO4 (m + n + q is 1 or less, 0 < m < 1, 0 < n < 1, 0 < q < 1 ), Li (2-j) Fe r Ni s Co t Mn u SiO4 (r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. Lithium compounds can be used as materials .

[0148] Also, as the positive electrode active material, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, Nb, Al, X = S, P, Mo, W, As, Si) represented by the general formula NASICON-type compounds can be used. Examples of NASICON-type compounds include Fe2(MnO4 )3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as the positive electrode active material , compounds represented by the general formula Li2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn), perovskite-type fluorides such as NaFeF3, FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, M oS2, and LiMVO4, etc. Oxides having an inverse spinel crystal structure, vanadium oxides (V2O5, V6O 13 , LiV3O8, etc.), manganese oxides, organic sulfur compounds, and other materials can be used.

[0149] In addition, when the carrier ion is an alkali metal ion other than lithium ion or an alkaline earth metal ion, as the positive electrode active material, instead of lithium, an alkali metal (e.g., sodium, potassium, etc.), an alkaline earth metal (e.g., calcium, strontium, barium, beryllium, magnesium, etc.) may be used.

[0150] As the separator 73, cellulose (paper) or an insulator such as polypropylene or polyethylene provided with pores can be used.

[0151] The electrolyte 77 uses, as the electrolyte, a material in which carrier ions can move and which has lithium ions as the carrier ions. Representative examples of the electrolyte include lithium salts such as LiPF6, LiClO4, LiAsF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N , Li(C2F5SO2)2N, etc. These electrolytes may be used alone or in any combination and ratio of two or more.

[0152] In addition, as the solvent of the electrolyte, a material in which carrier ions can move is used. As the solvent of the electrolyte, an aprotic organic solvent is preferable. Representative examples of the aprotic organic solvent include ethylene carbonate (EC), propylene carbonate, dimethyl carbonate, diethyl carbonate (DEC), γ-butyrolactone, acetonitrile, dimethoxyethane , ​​​​Examples include tetrahydrofuran and the like, and one or more of these can be used. Also By using a polymer material that gels as the solvent of the electrolytic solution, safety against leakage and the like is enhanced. Also, the battery can be made thinner and lighter. Instead of the polymer material that gels Examples include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide based gel, polypropylene oxide based gel, gel of fluorine-based polymer, and the like. Also, by using one or more ionic liquids (room temperature molten salts) that are flame retardant and hardly volatile as the solvent of the electrolytic solution, even if the internal temperature rises due to internal short circuit, overcharging, etc. of the battery rupture and ignition of the battery can be prevented. Note that an ionic liquid is a salt in a fluid state and has high ionic mobility (conductivity). Also, an ionic liquid contains a cation and an anion . Examples of ionic liquids include ionic liquids containing an ethylmethylimidazolium (EMI) cation , or ionic liquids containing an N-methyl-N-propylpiperidinium (PP 13 ) cation , and the like.

[0153] Also, instead of the electrolytic solution, a solid electrolyte having an inorganic material such as a sulfide-based or oxide-based material, or a solid electrolyte having a polymer material such as a PEO (polyethylene oxide)-based material can be used . When using a solid electrolyte, it becomes unnecessary to install a separator or a spacer. Also since the entire battery can be solidified, the risk of leakage disappears and the safety is dramatically improved.

[0154] Also, as the negative electrode active material of the negative electrode active material layer 79, a material capable of dissolving and depositing lithium or inserting and desorbing lithium ions can be used, and metallic lithium, carbon-based materials, alloy based materials, etc. can be used. ​

[0155] Metallic lithium has a low redox potential (-3.045 V vs. standard hydrogen electrode) and a large specific capacity per weight and volume (3860 mAh / g and 2062 mAh / cm 3 ), respectively), so it is preferable.

[0156] Examples of carbon-based materials include graphite, graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes, graphene, fullerenes, carbon black, etc. There are.

[0157] Examples of graphite include artificial graphite such as mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite, and natural graphite such as spherical natural graphite. There are.

[0158] Graphite exhibits a potential as low as that of metallic lithium (0.1 V or more and 0.3 V or less vs. Li / L i i + ) when lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound). As a result, lithium-ion secondary batteries can exhibit a high operating voltage. Furthermore , graphite has advantages such as a relatively high capacity per unit volume, small volume expansion, low cost, and high safety compared to metallic lithium, so it is preferable. There are.

[0159] As the negative electrode active material, an alloy-based material or an oxide capable of performing charge and discharge reactions by alloying and dealloying reactions with lithium can also be used. When the carrier ion is a lithium ion , examples of the alloy-based material include materials containing at least one of Al, Si, Ge, Sn, Pb, Sb, Bi , Ag, Au, Zn, Cd, In, Ga, etc. Among these , there are materials containing at least one of them. This Such elements have a large capacity with respect to carbon, and in particular, silicon has a theoretical capacity of 4200 mAh / g which is extremely high. Therefore, it is preferable to use silicon as the negative electrode active material. Such examples of alloy-based materials using such elements include Mg2Si, Mg2Ge, Mg2Sn, Sn S2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn , Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoS b3, InSb, SbSn, and the like.

[0160] In addition, as the negative electrode active material, oxides such as SiO, SnO, SnO2, titanium dioxide (TiO2), lithium titanium oxide (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6) , niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO 2), etc. can be used. Note that SiO refers to a powder of silicon-rich silicon oxide, and can also be expressed as SiO (2 > y > 0). For example, SiO y includes materials containing one or more selected from Si2O3, Si3O4, or Si2O , or a mixture of Si powder and silicon dioxide SiO2. In addition, SiO may contain other elements (carbon, nitrogen, iron, aluminum, copper, titanium, calcium, manganese, etc.). That is, SiO refers to a material containing a plurality selected from single crystal Si, amorphous Si, polycrystalline Si, Si2O3, Si3O4, Si2O, and SiO2. In addition, SiO is a colored material . SiO that is not SiO (x is 2 or more) is colorless and transparent or white, x and can be distinguished. However, when using SiO as the material of the secondary battery to fabricate a secondary battery ​After that, when SiO is oxidized by repeating charge and discharge, etc., it may be transformed into SiO2. There are also cases.

[0161] In addition, as the negative electrode active material, Li3N type structure, which is a complex nitride of lithium and transition metal, having Li 3-x M x N (M = Co, Ni, Cu) can be used. For example, Li 2. 6Co 0.4 N3 shows a large charge-discharge capacity (900 mAh / g, 1890 mAh / cm 3 ) and is preferable. It is shown and preferable.

[0162] When using a complex nitride of lithium and transition metal, since the negative electrode active material contains lithium ions, it can be preferably combined with materials such as V2O5 and Cr3O8 that do not contain lithium ions as the positive electrode active material. In addition, even when using a material containing lithium ions for the positive electrode active material, a complex nitride of lithium and transition metal can be used as the negative electrode active material by previously desorbing the lithium ions contained in the positive electrode active material.

[0163] In addition, a material that causes a conversion reaction can also be used as the negative electrode active material. For example, transition metal oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), which do not undergo an alloying reaction with lithium, may be used as the negative electrode active material. As materials that cause a conversion reaction, further, oxides such as Fe2O3, CuO, Cu2O, RuO2, and Cr2 O3, sulfides such as CoS 0.89 , NiS, and CuS, nitrides such as Zn3N2, Cu3N, Ge3N4, phosphides such as NiP2, FeP2, and CoP3, and fluorides such as FeF3 and BiF 3 also occur. In addition, since the potential of the above fluorides is high, when used as the positive electrode active material, It may be.

[0164] In addition, in the negative electrode active material layer 79, in addition to the above-described negative electrode active material, in order to enhance the adhesion of the active material it may have a binder for enhancing the conductivity of the negative electrode active material layer 79, a conductive assistant, etc. It is good.

[0165] The configuration of the secondary battery is, for example, the thickness of the separator 73 is about 15 μm or more and about 30 μm or less, the positive electrode current collector 72 is about 10 μm or more and about 40 μm or less, the positive electrode active material layer 78 is about 50 μm or more and about 100 μm or less, the negative electrode active material layer 79 is about 50 μm or more and about 100 μm or less, and the negative electrode current collector 74 can be about 5 μm or more and about 40 μm or less, etc. The thickness of the film-like exterior body 11 is about 20 μm or more and about 500 μm or less. Further, the height of the convex portion in the film-like exterior body 11 is about 5 μm or more and about 400 μm or less. When the height of the convex portion in the film-like exterior body 11 is 2 mm or more, the thickness of the entire secondary battery becomes too thick.

[0166] It is preferable that the capacity of the battery per unit volume is larger. The capacity of the battery per unit volume increases as the volume of the battery portion in the entire secondary battery increases. When the height of the convex portion in the film-like exterior body 11 is increased and the thickness of the entire secondary battery increases, the proportion of the battery occupying per unit volume decreases, and the capacity of the battery also decreases.

[0167] Note that a layer made of polypropylene is provided on the surface of the film on the side where the films are laminated, and only the thermocompression-bonded portion becomes the adhesive layer.

[0168] In addition, in FIG. 10(E), an example in which the lower side of the film-like exterior body 11 is fixed and pressure-bonded is is shown. In this case, the upper side is bent greatly and a step is formed, so that the folded film When a plurality of, for example, eight or more of the above-described laminate combinations are provided between the film-like exterior bodies 11 in the shape of a gable, the step becomes large and there is a risk that too much stress is applied to the upper film-like exterior body 11. Also, for this reason, there is also a risk that the displacement between the end of the upper film and the end of the lower film becomes large. In that case, a step may also be provided in the lower film so that there is no displacement at the end, and the structure may be such that pressure bonding is performed at the center so that the stress is equalized.

[0169] Also, when a large displacement occurs, there is a region where a part of the end of one film does not overlap with the other film. This region may be cut out and the ends of the upper film and the lower film may be aligned to correct the displacement.

[0170] Here, the flow of current during charging of the secondary battery will be described with reference to FIG. 11. When a secondary battery using lithium is regarded as a single closed circuit, the movement of lithium ions and the flow of current are in the same direction. In a secondary battery using lithium, the anode (positive electrode) and the cathode (negative electrode) are switched between charging and discharging, and the oxidation reaction and the reduction reaction are switched, so that the reaction potential The electrode with a high potential is called the positive electrode, and the electrode with a low potential is called the negative electrode. Therefore, in this specification, even during charging, even during discharging, even when a reverse pulse current is flowing, and even when a charging current is flowing, the positive electrode is called the "positive electrode" or the "+ electrode (plus electrode)", and the negative electrode is called the "negative electrode" or the "- electrode (minus electrode)". When using terms such as anode (positive electrode) and cathode (negative electrode) related to oxidation reaction and reduction reaction, during charging and discharging, ​​​​​​It may become reversed and cause confusion. Therefore, the terms anode and cathode shall not be used in this specification. If the terms anode or cathode are used, it shall be specified whether it is during charging or discharging, and it shall also be noted which corresponds to the positive electrode (plus electrode) or the negative electrode (minus electrode).

[0171] A charger is connected to the two terminals shown in FIG. 11, and the battery 10 is charged. As the charging of the battery 10 progresses, the potential difference between the electrodes increases. In FIG. 11, electrons flow from the external terminal of the battery 10 toward the positive electrode current collector 72. Inside the battery 10, a current flows from the positive electrode current collector 72 toward the negative electrode current collector 74, and the direction of the current flowing from the negative electrode toward the external terminal of the battery 10

[0172] [Example of Electrode Laminate] Hereinafter, a configuration example of a laminate having a plurality of laminated electrodes will be described.

[0173] FIG. 12(A) shows a top view of the positive electrode current collector 72, FIG. 12(B) shows the separator 73, FIG. 12(C) shows the negative electrode current collector 74, FIG. 12(D) shows the sealing layer 75 and the lead electrode 76, and FIG. 12(E) shows the film

[0174] In each figure of FIG. 12, the respective dimensions are approximately equal, and the region 71 surrounded by the dashed-dotted line in FIG. 12(E) is substantially the same as the dimension of the separator in FIG. 12(B). Also, the regions between the broken line and the ends in FIG. 12(E) become the joints 33 and 34, respectively.

[0175] FIG. 13(A) is an example in which the positive electrode active material layer 78 is provided on both sides of the Specifically, they are arranged in the order of the negative electrode current collector 74, the negative electrode active material layer 79, the separator 73, the positive electrode active material layer 7 8, the positive electrode current collector 72, the positive electrode active material layer 78, the separator 73, the negative electrode active material layer 79, the negative electrode current collector 74. A cross-sectional view when this laminated structure is cut by the plane 80 is shown in FIG. 13(B).

[0176] In addition, in FIG. 13(A), an example in which two separators are used is shown. However, it is also possible to fold a single separator, seal both ends to form a bag shape, and house the positive electrode current collector 72 therein. The positive electrode active material layer 78 is formed on both sides of the positive electrode current collector 72 housed in the bag-shaped separator.

[0177] Moreover, it is also possible to provide the negative electrode active material layer 79 on both sides of the negative electrode current collector 74. In FIG. 13 (C), an example of a secondary battery is shown in which between two negative electrode current collectors 74 each having the negative electrode active material layer 79 on only one side, there are three negative electrode current collectors 74 each having the negative electrode active material layer 79 on both sides, four positive electrode current collectors 72 each having the positive electrode active material layer 78 on both sides, and eight separators 73 are sandwiched. In this case as well, instead of using eight separators, four bag-shaped separators may be used.

[0178] By increasing the number of laminations, the capacity of the secondary battery can be increased. Also, by providing the positive electrode active material layer 78 on both sides of the positive electrode current collector 72 and providing the negative electrode active material layer 79 on both sides of the negative electrode current collector 74, the thickness of the secondary battery can be reduced.

[0179] FIG. 14(A) shows a diagram of a secondary battery formed by providing the positive electrode active material layer 78 on only one side of the positive electrode current collector 72 and providing the negative electrode active material layer 79 on only one side of the negative electrode current collector 74. Specifically described ​​​​Then, a negative electrode active material layer 79 is provided on one side of the negative electrode current collector 74, and the separator 73 is laminated so as to be in contact with the negative electrode active material layer 79. The surface of the separator 73 on the side not in contact with the negative electrode active material layer 79 is in contact with the positive electrode active material layer 78 of the positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side. On the surface of the positive electrode current collector 72, another positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side is further in contact. At this time, the positive electrode current collectors 72 are arranged such that the surfaces on which the positive electrode active material layer 78 is not formed face each other. Then, a separator 73 is further formed, and the negative electrode active material layer 79 of the negative electrode current collector 74 having the negative electrode active material layer 79 formed on one side is laminated so as to be in contact with the separator. A cross-sectional view when the laminated structure of FIG. 14(A) is cut by the plane 90 is shown in FIG. 14(B). In FIG. 14(A), two separators are used, but one separator may be bent, both ends may be sealed to form a bag shape, and two positive electrode current collectors 72 having the positive electrode active material layer 78 arranged on one side therebetween may be sandwiched. FIG. 14(C) shows a view in which a plurality of the laminated structures of FIG. 14(A) are laminated. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated. A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72. Then, a negative electrode active material layer 79 is provided on one side of the negative electrode current collector 74, and the separator 73 is laminated so as to be in contact with the negative electrode active material layer 79. The surface of the separator 73 on the side not in contact with the negative electrode active material layer 79 is in contact with the positive electrode active material layer 78 of the positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side. On the surface of the positive electrode current collector 72, another positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side is further in contact. At this time, the positive electrode current collectors 72 are arranged such that the surfaces on which the positive electrode active material layer 78 is not formed face each other. Then, a separator 73 is further formed, and the negative electrode active material layer 79 of the negative electrode current collector 74 having the negative electrode active material layer 79 formed on one side is laminated so as to be in contact with the separator. A cross-sectional view when the laminated structure of FIG. 14(A) is cut by the plane 90 is shown in FIG. 14(B). In FIG. 14(A), two separators are used, but one separator may be bent, both ends may be sealed to form a bag shape, and two positive electrode current collectors 72 having the positive electrode active material layer 78 arranged on one side therebetween may be sandwiched. FIG. 14(C) shows a view in which a plurality of the laminated structures of FIG. 14(A) are laminated. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated. A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72. Then, a negative electrode active material layer 79 is provided on one side of the negative electrode current collector 74, and the separator 73 is laminated so as to be in contact with the negative electrode active material layer 79. The surface of the separator 73 on the side not in contact with the negative electrode active material layer 79 is in contact with the positive electrode active material layer 78 of the positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side. On the surface of the positive electrode current collector 72, another positive electrode current collector 72 having the positive electrode active material layer 78 formed on one side is further in contact. At this time, the positive electrode current collectors 72 are arranged such that the surfaces on which the positive electrode active material layer 78 is not formed face each other. Then, a separator 73 is further formed, and the negative electrode active material layer 79 of the negative electrode current collector 74 having the negative electrode active material layer 79 formed on one side is laminated so as to be in contact with the separator. A cross-sectional view when the laminated structure of FIG. 14(A) is cut by the plane 90 is shown in FIG. 14(B).

[0180] In FIG. 14(A), two separators are used, but one separator may be bent, both ends may be sealed to form a bag shape, and two positive electrode current collectors 72 having the positive electrode active material layer 78 arranged on one side therebetween may be sandwiched. FIG. 14(C) shows a view in which a plurality of the laminated structures of FIG. 14(A) are laminated. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated. A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72.

[0181] FIG. 14(C) shows a view in which a plurality of the laminated structures of FIG. 14(A) are laminated. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated. A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72. In FIG. 14(C), the surfaces of the negative electrode current collector 74 on which the negative electrode active material layer 79 is not formed face each other. FIG. 14(C) shows a state in which 12 positive electrode current collectors 72, 12 negative electrode current collectors 74, and 12 separators 73 are laminated.

[0182] A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72. A structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and laminated is different from a structure in which the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72. Compared with the structure in which the negative electrode active material layer 79 is provided on both sides of the negative electrode current collector 74, the thickness of the secondary battery will increase significantly. However, the surface of the positive electrode current collector 72 where the positive electrode active material layer 78 is not formed faces the surface of another positive electrode current collector 72 where the positive electrode active material layer 78 is not formed, and the metals are in contact with each other. Similarly, the surface of the negative electrode current collector 74 where the negative electrode active material layer 79 is not formed faces the surface of another negative electrode current collector 74 where the negative electrode active material layer 79 is not formed, and the metals are in contact with each other. Due to the contact between the metals, a large frictional force acts, and the surfaces where the metals are in contact are easily slidable. Therefore, when the secondary battery is bent, the metals slide inside the secondary battery, making the secondary battery easy to bend.

[0183] Also, the protruding portions of the positive electrode current collector 72 and the negative electrode current collector 74 are also called tab portions. When the secondary battery is bent, the tab portions of the positive electrode current collector 72 and the negative electrode current collector 74 are easily cut. This is because the tab portions have an elongated shape that protrudes, making it easy for stress to be applied to the base of the tab portions.

[0184] The structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and they are laminated has the surfaces where the positive electrode current collectors 72 contact each other and the surfaces where the negative electrode current collectors 74 contact each other. The surfaces where the current collectors contact each other have a small frictional resistance and are easy to release the stress caused by the difference in the radius of curvature that occurs when the battery is deformed. Also, the structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and they are laminated also increases the total thickness of the tab portions. Therefore, compared with the case where the positive electrode active material is provided on both sides of the positive electrode current collector 72, the structure is more resistant to deformation. When the battery is deformed, the stress caused by the difference in the radius of curvature can be easily released. Also, the structure in which the positive electrode active material layer 78 is provided only on one side of the positive electrode current collector 72 and the negative electrode active material layer 79 is provided only on one side of the negative electrode current collector 74 and they are laminated increases the total thickness of the tab portions. Therefore, compared with the case where the positive electrode active material layer 78 is provided on both sides of the positive electrode current collector 72, the structure is more resistant to deformation. ​A structure is provided with a layer 78, and compared with a structure in which negative electrode active material layers 79 are provided on both sides of a negative electrode current collector 74, stress is dispersed, and it becomes difficult for disconnection to occur at the tab portion. When the positive electrode current collectors 72 are all fixed and electrically connected in this stacked manner, ultrasonic welding that can be joined at one time is performed. Further, in addition to the positive electrode current collector 72, ultrasonic welding is also performed by overlapping with the lead electrode, and electrical connection can be performed efficiently.

[0185] By applying ultrasonic waves while pressing the tab portion against the tab portion of another positive electrode current collector, ultrasonic welding can be performed. When the positive electrode current collectors 72 are all fixed and electrically connected in this stacked manner, ultrasonic welding that can be joined at one time is performed. Further, in addition to the positive electrode current collector 72, ultrasonic welding is also performed by overlapping with the lead electrode, and electrical connection can be performed efficiently.

[0186] By applying ultrasonic waves while pressing the tab portion against the tab portion of another positive electrode current collector, ultrasonic welding can be performed.

[0187]

[0188] These formation methods may make reference to the above. Also, here, an example is shown in which the positive electrode current collector 72 and the negative electrode current collector 74 are alternately arranged. However, as described above, a configuration in which two positive electrode current collectors 72 are continuous with each other, or two negative electrode current collectors 74 are continuous with each other may also be used.

[0189] In this embodiment, an example of a structure in which a single rectangular film is bent at the center and two end portions are overlapped and sealed is shown. However, the shape of the film is not limited to a rectangle. It may be any polygon such as a triangle, square, pentagon, etc., or any symmetric shape other than a rectangle such as a circle or star.

[0190] In this embodiment, an example of a small battery used in a portable information terminal or the like is shown. However, it is not particularly limited and can also be applied to large batteries mounted on vehicles or the like.

[0191] Note that in this embodiment, an example of the case of applying to a lithium ion secondary battery is shown. However, one aspect of the present invention is not limited to this. It can also be applied to various secondary batteries, for example, lead-acid batteries, lithium ion polymer secondary batteries, nickel-hydrogen storage batteries, nickel-cadmium storage batteries, nickel -iron storage batteries, nickel-zinc storage batteries, silver oxide-zinc storage batteries, solid batteries, air batteries, etc. It is also possible to apply to various power storage devices, for example, primary batteries, capacitors, lithium ion capacitors, etc. It is also possible to apply to, for example, solar cells, optical sensors, touch sensors, display devices, FPC (flexible printed circuit board), optical films (polarizing plates, retardation plates, prism sheets, light reflection sheets, light diffusion sheets, etc.).

[0192] This embodiment may appropriately combine at least a part thereof with other embodiments described in this specification. They can be implemented in combination.

[0193] (Embodiment 2) In this embodiment, an example of an electronic device incorporating a battery obtained using Embodiment 1, particularly a secondary battery, is shown. An example of an electronic device is shown.

[0194] The secondary battery obtained using Embodiment 1 has an exterior body that is a thin and flexible film, and can be deformed into a flexible shape. It can be deformed into a flexible shape.

[0195] By bringing a part of the electronic device into contact with a part of the user's body (such as the wrist or arm), that is, by attaching the electronic device to the user, as in the case of a watch, the user can feel that the electronic device is lighter than its actual weight. By using a flexible secondary battery for an electronic device having an external shape with a curved surface along a part of the user's body, the secondary battery can be fixed and installed in a shape suitable for the electronic device. It can be felt that the electronic device is lighter than its actual weight. By using a flexible secondary battery for an electronic device having an external shape with a curved surface along a part of the user's body, the secondary battery can be fixed and installed in a shape suitable for the electronic device. By using a flexible secondary battery for an electronic device having an external shape with a curved surface along a part of the user's body, the secondary battery can be fixed and installed in a shape suitable for the electronic device. It can be installed.

[0196] Also, when the user moves the part where the electronic device is attached, even if the electronic device has a curved surface along a part of the body, the user may feel discomfort, recognize the electronic device as an obstructive object, and feel stressed. Therefore, by providing a flexible secondary battery in a part of the electronic device that can be deformed, it is possible to configure at least a part of the electronic device to be deformable in accordance with the movement of the body, and an electronic device that does not cause discomfort to the user can be obtained. Even if the electronic device has a curved surface along a part of the body, the user may feel discomfort, recognize the electronic device as an obstructive object, and feel stressed. Therefore, by providing a flexible secondary battery in a part of the electronic device that can be deformed, it is possible to configure at least a part of the electronic device to be deformable in accordance with the movement of the body, and an electronic device that does not cause discomfort to the user can be obtained. Therefore, by providing a flexible secondary battery in a part of the electronic device that can be deformed, it is possible to configure at least a part of the electronic device to be deformable in accordance with the movement of the body, and an electronic device that does not cause discomfort to the user can be obtained. It can be made into an electronic device that does not cause discomfort to the user. .

[0197] Alternatively, it is not limited to the case where the external shape of the electronic device is a curved surface or a complex shape, and it may have a simple external shape. For example, inside an electronic device with a simple external shape, an electronic device It may have a simple external shape. For example, inside an electronic device with a simple external shape, an electronic device The number and size of components that can be built into the device are often determined by the volume of the space formed by the housing of the electronic device. By providing a flexible secondary battery in the gaps between components other than the secondary battery, the space formed by the housing of the electronic device can be effectively utilized, and the device can also be miniaturized.

[0198] Note that a wearable device includes wearable input terminals such as a wearable camera, a wearable microphone, and a wearable sensor, wearable output terminals such as a wearable display and a wearable speaker, and wearable input / output terminals having those functions combined. In addition, a wearable device includes devices that perform control, data calculation, or processing of each device, typically a wearable computer having a CPU. In addition, a wearable device includes devices that store, transmit, or receive data, typically a portable information terminal, a memory, and the like.

[0199] As an electronic device to which a secondary battery having a flexible shape is applied, for example, a display device such as a head-mounted display or a goggle-type display, a television (also called a television receiver), a personal computer such as a desktop type or a notebook type, a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, an electronic notebook, an electronic book terminal, an electronic translator, a toy, an audio input device such as a microphone, a high-frequency heating device such as an electric shaver, an electric toothbrush, and a microwave oven, an electric rice cooker, an electric washing machine, an electric vacuum cleaner, a water heater, a fan, a hair dryer, an air conditioner such as a humidifier or a dehumidifier, a dishwasher, a dish dryer, a clothes dryer, a futon dryer, an electric refrigerator, an electric freezer, Air-cooled refrigerators, freezers for DNA preservation, flashlights, power tools, smoke sensors, gas alarm devices, anti-theft alarm devices, etc., industrial robots, hearing aids, cardiac pacemakers, X-ray imaging devices, radiation measuring instruments, health devices and medical devices such as electric massagers and dialysis devices, mobile phones (also called mobile phones, mobile phone devices), portable game machines, portable information terminals, lighting devices, headphones, stereos, remote controllers, clocks such as table clocks and wall clocks, cordless telephone handsets, transceivers, pedometers, calculators, portable or stationary audio playback devices such as digital audio players, large game machines such as pachinko machines, etc. Moreover, it is also possible to incorporate a secondary battery having a flexible shape along the inner or outer wall of a house or building, or along the curved surface of the interior or exterior of an automobile. FIG. 16(A) shows an example of a mobile phone. The mobile phone 7400 includes a display unit 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, etc. The mobile phone 7400 has a secondary battery 7407.

[0200] FIG. 16(B) shows a state in which the mobile phone 7400 is bent. When the mobile phone 7400 is deformed by an external force and bent as a whole, the secondary battery 7407 provided inside it is also bent. Also, at that time, the state of the bent secondary battery 7407 is shown in FIG. 16(C). The secondary battery 7407 is a laminated structure storage battery (also called a laminated structure battery, a film-packaged battery). The secondary battery 7407 is fixed in a bent state.

[0201]

[0202] ​​​​​​​​​​, the secondary battery 7407 has a lead electrode 7408 electrically connected to the current collector 7409. For example, embossing is performed on the film of the exterior body of the secondary battery 7407, and the configuration has high reliability when the secondary battery 7407 is bent. Furthermore, the mobile phone 7400 may be provided with a slot for inserting a SIM card, a connector portion for connecting USB devices such as a USB memory, and the like.

[0203] FIG. 16(D) shows an example of a bendable mobile phone. If it is bent into a shape that can be wound around the forearm, it can be made into the bangle-type mobile phone shown in FIG. 16(E). The mobile phone 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a secondary battery 71 04. FIG. 16(F) shows the secondary battery 7104 in a bent state. When the secondary battery 7 104 is bent and worn on the user's arm, the housing deforms and the curvature of part or all of the secondary battery 7104 changes. Specifically, part or all of the main surface of the housing or the secondary battery 7104 changes within a range where the radius of curvature is 10 mm or more and 150 mm or less. Note that the secondary battery 7104 has a lead electrode 7105 electrically connected to the current collector 7106. For example, pressing is performed to form a plurality of irregularities on the surface of the film of the exterior body of the secondary battery 7104, and high reliability can be maintained even when the secondary battery 7104 is bent with a changing curvature a large number of times. Furthermore, the mobile phone 7100 may be provided with a slot for inserting a SIM card, a connector portion for connecting USB devices such as a USB memory, and the like. Also, if the central portion of the mobile phone shown in FIG. 16(D) is bent, it can be made into the shape shown in FIG. 16(G ). Also, if the central portion of the mobile phone is further bent, it can also be made into the shape shown in FIG. 16(G). As shown in Fig. 16(H), the ends of the mobile phone are overlapped to reduce the size, so that it can be made small enough to fit into the user's pocket or the like. Thus, the mobile phone shown in Fig. 16(D) is an electronic device that can change its shape. To achieve this, at least the housing 7101, the display unit 7102, and the secondary battery 7104 are preferably flexible.

[0204] Fig. 17(A) shows an example of a vacuum cleaner. By equipping the vacuum cleaner with a secondary battery, it can be made cordless. Since a dust collection space for sucking and storing dust is secured inside the vacuum cleaner, it is preferable that the space occupied by the secondary battery 7604 is as small as possible. Therefore, it is useful to arrange a thin secondary battery 7604 that can be bent between the outer surface and the dust collection space.

[0205] The vacuum cleaner 7600 includes an operation button 7603 and a secondary battery 7604. Fig. 17(B) shows the secondary battery 7604 in a bent state. The secondary battery 7604 has an embossed film on its outer casing, and has a high-reliability structure when the secondary battery 7604 is bent. The secondary battery 7604 has a lead electrode 7601 electrically connected to the negative electrode and a lead electrode 7602 electrically connected to the positive electrode.

[0206] As an example of a secondary battery in which one current collector is exposed on each short side of the outer casing, Fig. 17(C) shows the secondary battery 7605 in a bent state. In Fig. 17(C), for the secondary battery 7605, a part of the positive current collector 72 is exposed from one short side of the outer casing, and a part of the negative current collector 74 is exposed from the other short side of the outer casing. The film of the outer casing of the secondary battery 7605 It is also embossed, can be bent, and has high reliability. Note that one of the short sides of the exterior body may be configured to expose one lead electrode.

[0207] The thin secondary battery 7604 can be manufactured using the method for manufacturing a secondary battery having a laminate structure shown in Embodiment 1.

[0208] The thin secondary battery 7604 has a laminate structure and is bent and fixed. Further, the vacuum cleaner 7600 has a display unit 7606 that displays the remaining power of the thin secondary battery 7604, etc., and the display surface is also curved in accordance with the shape of the outer surface of the vacuum cleaner. There is a display unit 7606. Also, the vacuum cleaner has a connection cord for connecting to an outlet, and if the thin secondary battery 7604 is sufficiently charged, the vacuum cleaner can be used with the connection cord removed. Also, the thin secondary battery 7604 may be charged wirelessly without using a connection cord.

[0209] Also, when a bendable secondary battery is mounted on a vehicle, next-generation clean energy vehicles such as hybrid vehicles (HEV), electric vehicles (EV), or plug-in hybrid vehicles (PHEV) can be realized. In addition, mobile bodies such as agricultural machines, motorized bicycles including electric assist bicycles, motorcycles, electric wheelchairs, electric carts, small or large ships, submarines, airplanes such as fixed-wing aircraft and rotary-wing aircraft, rockets, artificial satellites, space exploration vehicles, planetary exploration vehicles, and spaceships can also be equipped with bendable secondary batteries.

[0210] In FIG. 18, a vehicle using one aspect of the present invention is illustrated. The automobile shown in FIG. 18(A) ​​​​​​​​​​The 8100 is an electric vehicle that uses an electric motor as a power source for driving. Or , it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as power sources for driving. When a secondary battery with a laminate structure is mounted on the vehicle, a battery module in which a plurality of secondary batteries with a laminate structure are integrated is provided at one or more locations. By using one aspect of the present invention, the secondary battery itself can be reduced in size and weight. For example, a secondary battery having a curved surface is provided inside the tire, and a vehicle with a long cruising range can be realized. In addition, secondary batteries with various shapes can be arranged in the gaps of the vehicle, ensuring the space for the trunk and the riding space inside the vehicle. Further, the automobile 8100 has a secondary battery. The secondary battery can not only drive the electric motor but also supply power to a lighting device such as a headlight 8101 and a room light (not shown).

[0211] In addition, the secondary battery can supply power to display devices such as a speedometer and a tachometer that the automobile 8100 has. Further, the secondary battery can supply power to semiconductor devices such as a navigation system that the automobile 8100 has.

[0212] The automobile 8200 shown in Fig. 18(B) can be charged by receiving power supply from an external charging facility by a plug-in method, a non-contact power supply method, or the like to the secondary battery that the automobile 8200 has. Fig. 18(B) shows a state in which charging is being performed from a ground-mounted charging device 8021 to the secondary battery mounted on the automobile 8200 via a cable 8022. When charging, the charging method, the connector standard, etc. are in accordance with a predetermined method such as CHAdeMO (registered trademark) or Combo. It is sufficient to be feasible. The charging device 8021 may be a charging station provided in a commercial facility, or it may be a household power source. For example, by plug-in technology, the secondary battery mounted on the vehicle 8200 can be charged by external power supply. Charging can be performed by converting AC power into DC power through a conversion device such as an AC-DC converter.

[0213] Also, although not shown, a power receiving device can be mounted on the vehicle, and power can be supplied and charged non-contact from a power transmission device on the ground. In the case of this non-contact power supply method, by incorporating the power transmission device into a road or an outer wall, charging can be performed not only while the vehicle is stopped but also while it is running. Also, power can be transmitted and received between two vehicles using this non-contact power supply method. Furthermore, a solar cell can be provided on the exterior of the vehicle to charge the secondary battery when the vehicle is stopped or running. For such non-contact power supply, an electromagnetic induction method or a magnetic field resonance method can be used.

[0214] According to one aspect of the present invention, the degree of freedom in the installation location of the secondary battery is increased, and vehicle design can be efficiently performed. Also, according to one aspect of the present invention, the characteristics of the secondary battery can be improved, and thus the secondary battery itself can be reduced in size and weight. If the secondary battery itself can be reduced in size and weight, it contributes to weight reduction of the vehicle, and thus the cruising range can be improved. Also, the secondary battery mounted on the vehicle can be used as a power supply source other than the vehicle. In this case, it is possible to avoid using commercial power at the peak of power demand.

[0215] This embodiment can be implemented in appropriate combination with at least some of the other embodiments described in this specification.

Example

[0216] In this example, a bendable battery as exemplified in Embodiment 1 is used as a battery according to one embodiment of the present invention. We will explain the results of making a battery (lithium ion secondary battery) that can be used for Reveal.

[0217] Lithium-ion secondary batteries use LiCoO2 as the positive electrode active material and The product is made of graphite and has an embossed aluminum laminate film for the exterior. The cathode was fabricated according to the fabrication method exemplified in Example 1. Six copper foil collectors with a negative electrode active material layer on one side and six copper foil collectors with a negative electrode active material layer on the other side were alternately laminated. The thickness of the electrode laminate was about 1.5 mm.

[0218] The exterior is made of polypropylene, aluminum foil, and nylon laminated in that order, with a thickness of approximately A 110μm aluminum laminate film was used. The wave pitch was 2mm, and the convex and concave portions The film was processed so that the difference in height was 0.5 mm.

[0219] The film is joined using a mold (heat bar) with a flat surface. The pair of joining layers (side seals) perpendicular to the ridges and valleys of the waves were A 1mm heat bar is used, and the pressure is 600kPa / cm 2 , and press at a temperature of 175 degrees. On the other hand, the bonding layer (top seal) parallel to the ridges and valleys of the waves was formed. A 2mm wide heat bar with a groove at the position opposite the board was used, and a pressure of 125kP was applied. a / cm 2 It was formed by pressing at a temperature of 175 degrees.

[0220] Here, two types of samples prepared as follows were prepared. One is the part that becomes the bent part The film was flattened, and the film was further bent so that the phase of the wave at the overlapping part was shifted by approximately 180 degrees That is, the film was bent so that the ridges of the waves and the valleys of the waves approximately overlapped each other, and the resulting sample was designated as Sample 1. For flattening, the heat bar press method was used, and the pressure was 60 kPa / cm 2 Flattening was performed on a region approximately 6 mm wide with the ridge of the wave as the boundary under the conditions of a temperature of 100 degrees.

[0221] The other was prepared by bending the film so that the phases of the waves matched, that is, so that one ridge and the other valley overlapped each other, and the resulting sample was designated as Sample 2.

[0222] For the two prepared samples, the inside of the secondary battery was observed using X-ray CT (X-ray computed tomography).

[0223] External photographs of Sample 1 are shown in FIGS. 19(A) and (B), and external photographs of Sample 2 are shown in FIGS. 19(C) and (D). As described above, it was found that the joint portions of both Sample 1 and Sample 2 were formed extremely flat. Also, in both cases, in the portion near the end of the film, a part of the film was deformed so that the wave period was longer and the wave amplitude was smaller than in the central portion.

[0224] Transmission X-ray photographs taken of Sample 1 are shown in FIGS. 20(A) and (B). FIG. 20(A) is a photograph in plan view, and FIG. 20(B) is a photograph in the lateral direction. As shown in FIG. 20(A), the bent part curves so that it is located more inward the farther it is from the joint part (side seal). ​​​​​​It was found that it has the following shape. Also, as shown in FIG. 20(B), it was found that a space is formed between the electrode laminate and the film.

[0225] FIGS. 21(A) and (B) show transmission X-ray photographs taken of Sample 2. Similar to Sample 1, it was found that the bent portion is curved so as to be located more inward as it is farther from the joint portion. Also, it was found that a space is formed between the electrode laminate and the film.

[0226] FIG. 22(A) shows an enlarged view of the X-ray CT image of Sample 1 when the bent portion is viewed from the lateral direction. In Sample 1, it was found that the shape of the bent portion is a neat arc shape that is approximately bilaterally symmetric. Also, from this photograph, the distance between the electrode laminate and the inner wall of the film was about 2.2 mm near the center of the electrode laminate and about 2.0 mm near the end portion. Furthermore, as shown in FIG. 22(A), since the bent portion of the film is formed so as to connect the ridgelines of the waves, the space inside the film is widely formed in the thickness direction, and it was confirmed that the end portion of the electrode laminate does not contact the surface of the film.

[0227] FIG. 22(B) shows an enlarged view of the X-ray CT image of Sample 2 when the bent portion is viewed from the lateral direction. In Sample 2, it was confirmed that the shape of the bent portion is an asymmetric and distorted shape. Also, in Sample 2, while there is a portion where the distance between the electrode laminate and the inner wall of the film is about 2.4 mm at maximum, there is a narrow portion of about 1.3 mm, and it was found that sufficient space is not secured compared to Sample 1. Furthermore, as shown in FIG. 22(B), since there is a portion where one end of the electrode laminate is in contact with the film, when the battery is bent, ​​​​​​​​​​​​​​It was confirmed that there was a risk of these rubbing against each other.

[0228] From the above results, it was confirmed that by shifting the phase of the wave possessed by the film by 180 degrees, the shape of the bent portion could be made symmetric with respect to the thickness direction. Also, by flattening a part that becomes the bent portion of the film so as to connect the ridge lines, it was found that waves do not locate in the portion where space is formed, and a wider space can be formed also in the thickness direction.

Example

[0229] Hereinafter, the results of the tensile test of the film will be described.

[0230] The same film as that used in Example 1 above was used for the test. The test piece was cut out into a rectangle of 15 mm × 100 mm.

[0231] In the tensile test, the upper and lower parts of the test piece were clamped and the force required was measured while changing these distances in the pulling direction. The distance between the clamps before pulling was set to 50 mm. For the test, EZ-Graph (manufactured by Shimadzu Corporation) was used.

[0232] Fig. 23 shows the results of the tensile test. The horizontal axis indicates the displacement amount of the test piece, and the vertical axis indicates the tensile strength. Up to around 4 mm of the displacement amount, it changes linearly with a gentle slope, indicating that the embossed shape of the waveform is being deformed as if it is being stretched. That is, this shows that the film can be deformed with a small force. Also, after that, the strength rapidly increases, indicating that the test piece itself is stretching.

[0233] From the above, a laminated film with an embossed shape that can be easily stretched is used for the battery ​​​​By using it for the exterior body, a battery that can be flexibly bent and stretched can be provided.

Example

[0234] In this example, a battery according to one aspect of the present invention was fabricated, and the effect on the sealing performance by the bending test was examined. Specifically, the amount of moisture infiltration into the film was measured for samples subjected to the bending test and those not subjected to the bending test.

[0235] The battery used in this example was fabricated in the same manner as Sample 1 of Example 1 except for the bonding temperature of the film. That is, the film was folded and bent so that the ridges and valleys of the waves were approximately overlapped. The film was bonded under the conditions of a temperature of 185 °C for both the side seal and the top seal.

[0236] The fabricated battery had a top seal length of about 15 mm and a side seal length of about 52 mm. Also, about 400 μL of propylene carbonate (PC) was used as the electrolyte.

[0237] The measurement of the amount of moisture infiltration into the film was performed by the following method. First, a pressure cooker filled with water was prepared, and the fabricated battery was placed in the pressure cooker so as to be submerged. Subsequently, the pressure cooker was placed in a thermostatic bath maintained at a temperature of 120 °C and heated for about 25.5 hours to boil the battery. After that, the battery was taken out, the film was opened in a glove box, and 400 μL of PC was added. After allowing the added PC to mix with the electrolyte inside the battery, about 0.3 g of this mixture was collected. Then, the amount of moisture in the collected mixture was measured with a moisture meter. As the moisture meter, a Karl Fischer moisture meter (manufactured by Kyoto Industry Co., Ltd., MKC610) was used. The amount of moisture ingress into the lumen was estimated by subtracting the amount of moisture originally contained in the PC itself from the measured amount of moisture. It was estimated by the value obtained by subtracting the amount of moisture originally contained in the PC itself from the measured amount of moisture.

[0238] Also, the batteries used for measuring the amount of moisture ingress were the following four types. The first one is the one that does not perform a bending test (Condition 1). The second one is the one that repeatedly bends and stretches the battery with a radius of curvature of 40 mm for 10,000 times (Condition 2). The third one is the one obtained by heating the fabricated battery at 160 °C for 15 minutes (Condition 3). The fourth one is the one obtained by heating the fabricated battery at 160 °C for 15 minutes and further repeatedly bending and stretching it with a radius of curvature of 40 mm for 10,000 times (Condition 4). is.

[0239] Figure 24(A) shows the measured moisture ingress amounts for the batteries of Condition 1 and Condition 2. For Condition 1, the number of measurements is 5, and for Condition 2, the number of measurements is 7. Condition 2, where the bending and stretching were performed, had equivalent values compared to Condition 1. Therefore, it was confirmed that the sealing performance of the film does not deteriorate even when the bending and stretching are repeatedly performed. Note that in Condition 2, one sample with a prominent moisture ingress amount was confirmed, but the moisture ingress amount was less than 110 ppm, which is a sufficient value for the sealing performance of the battery. Although one sample with a prominent moisture ingress amount was confirmed in Condition 2, the moisture ingress amount was less than 110 ppm, which is a sufficient value for the sealing performance of the battery.

[0240] Figure 24(B) shows the measured moisture ingress amounts for the batteries of Condition 3 and Condition 4. For Condition 3, the number of measurements is 5, and for Condition 4, the number of measurements is 3. As shown in Condition 3, it was confirmed that sufficient sealing performance can be recognized even when heating is performed. Also, as shown in Condition 4, it was confirmed that the sealing performance does not deteriorate even when the bending and stretching are further repeatedly performed. Note that in Condition 4, there is also a tendency for the sealing performance to be slightly improved compared to Condition 3.

[0241] From the above, it was confirmed that the battery of one aspect of the present invention has sufficient resistance to repeated bending and stretching and high-temperature environments.

Example

[0242] In this example, batteries were fabricated using exterior bodies of different thicknesses, and the force required for bending was measured.

[0243] In this example, batteries (Sample 3, Sample 4, Sample 5) were fabricated using the following three types of exterior bodies. The exterior bodies used for each were aluminum laminate films in which polypropylene, aluminum foil, and nylon were laminated in that order. For Sample 3, a film with an aluminum foil thickness of approximately 40 μm and a total thickness of approximately 110 μm was used. For Sample 4, a film with an aluminum foil thickness of approximately 30 μm and a total thickness of approximately 70 μm was used. For Sample 5, a film with an aluminum foil thickness of approximately 20 μm and a total thickness of approximately 50 μm was used.

[0244] Note that Samples 3, 4, and 5 were fabricated by the same method as in Example 3 except for the material of the exterior body.

[0245] Subsequently, for the three fabricated samples, the force required for bending was measured by the following method. Figures 25(A) and (B) show schematic diagrams explaining the measurement method. The measuring device has a concave member on the lower side and a convex member on the upper side. The radius of curvature of the curved surfaces of the concave member and the convex member is 30 mm. The sample is placed such that both ends thereof are supported by the edge portions of the concave portions of the concave member. Then, as shown in Figure 25(B), while pressing the convex portion of the convex member against the sample, the convex member is displaced downward so that the sample curves from a flat state. At this time, the convex member is ​​​​​​​​​​​​The force required for bending the sample was evaluated by measuring the force required for displacement downward. For the measurement, a small benchtop precision universal testing machine (EZ-Graph) manufactured by Shimadzu Corporation was used. For the measurement, a small benchtop precision universal testing machine (EZ-Graph) manufactured by Shimadzu Corporation was used.

[0246] Fig. 26 shows the measurement results. The horizontal axis in Fig. 26 is the displacement amount of the convex member, and the vertical axis is the force required for displacement. In Fig. 26, the force required for bending increases from around a displacement of 6 mm because the lower surface of the sample comes into contact with the upper surface of the concave member and the force that crushes the sample becomes dominant. Looking at the range of displacement of 6 mm or less, it can be confirmed that for any sample, the force required for bending is 2 N or less, and the battery is very easy to bend. Looking at the range of displacement of 6 mm or less, it can be confirmed that for any sample, the force required for bending is 2 N or less, and the battery is very easy to bend. Looking at the range of displacement of 6 mm or less, it can be confirmed that for any sample, the force required for bending is 2 N or less, and the battery is very easy to bend.

[0247] Looking at the range of displacement of 6 mm or less, it can be confirmed that for any sample, the force required for bending is 2 N or less, and the battery is very easy to bend. Looking at the range of displacement of 6 mm or less, it can be confirmed that for any sample, the force required for bending is 2 N or less, and the battery is very easy to bend.

[0248] Also, as shown in Fig. 26, it was confirmed that for any sample, the greater the displacement, that is, the smaller the radius of curvature of the sample, the greater the tendency for the force required for bending to increase. This is because the battery has elastic properties, and the smaller the radius of curvature, the greater the force to return to the original shape. In particular, since a film processed into a wave shape is used for the exterior body, it is presumed that the restoring force of the exterior body is dominant. Also, as shown in Fig. 26, it was confirmed that for any sample, the greater the displacement, that is, the smaller the radius of curvature of the sample, the greater the tendency for the force required for bending to increase. This is because the battery has elastic properties, and the smaller the radius of curvature, the greater the force to return to the original shape. In particular, since a film processed into a wave shape is used for the exterior body, it is presumed that the restoring force of the exterior body is dominant. Also, as shown in Fig. 26, it was confirmed that for any sample, the greater the displacement, that is, the smaller the radius of curvature of the sample, the greater the tendency for the force required for bending to increase. This is because the battery has elastic properties, and the smaller the radius of curvature, the greater the force to return to the original shape. In particular, since a film processed into a wave shape is used for the exterior body, it is presumed that the restoring force of the exterior body is dominant. Also, as shown in Fig. 26, it was confirmed that for any sample, the greater the displacement, that is, the smaller the radius of curvature of the sample, the greater the tendency for the force required for bending to increase. This is because the battery has elastic properties, and the smaller the radius of curvature, the greater the force to return to the original shape. In particular, since a film processed into a wave shape is used for the exterior body, it is presumed that the restoring force of the exterior body is dominant. Also, as shown in Fig. 26, it was confirmed that for any sample, the greater the displacement, that is, the smaller the radius of curvature of the sample, the greater the tendency for the force required for bending to increase. This is because the battery has elastic properties, and the smaller the radius of curvature, the greater the force to return to the original shape. In particular, since a film processed into a wave shape is used for the exterior body, it is presumed that the restoring force of the exterior body is dominant.

[0249] Also, when comparing the samples, as shown in Fig. 26, it was confirmed that the thinner the exterior body, the lower the force required for bending. For example, when comparing Sample 3 and Sample 5 at a displacement of 4 mm, the difference in the force required for bending is about twice, which is equivalent to the difference in thickness. Also, when comparing Sample 4 and Sample 5, the difference in the force required for bending is about 1.3 times, and the difference in thickness is about 1.4 times, so this is also equivalent to the difference in thickness. Therefore, the bending force is proportional to the thickness difference. Also, when comparing the samples, as shown in Fig. 26, it was confirmed that the thinner the exterior body, the lower the force required for bending. For example, when comparing Sample 3 and Sample 5 at a displacement of 4 mm, the difference in the force required for bending is about twice, which is equivalent to the difference in thickness. Also, when comparing Sample 4 and Sample 5, the difference in the force required for bending is about 1.3 times, and the difference in thickness is about 1.4 times, so this is also equivalent to the difference in thickness. Therefore, the bending force is proportional to the thickness difference. Also, when comparing the samples, as shown in Fig. 26, it was confirmed that the thinner the exterior body, the lower the force required for bending. For example, when comparing Sample 3 and Sample 5 at a displacement of 4 mm, the difference in the force required for bending is about twice, which is equivalent to the difference in thickness. Also, when comparing Sample 4 and Sample 5, the difference in the force required for bending is about 1.3 times, and the difference in thickness is about 1.4 times, so this is also equivalent to the difference in thickness. Therefore, the bending force is proportional to the thickness difference. Also, when comparing the samples, as shown in Fig. 26, it was confirmed that the thinner the exterior body, the lower the force required for bending. For example, when comparing Sample 3 and Sample 5 at a displacement of 4 mm, the difference in the force required for bending is about twice, which is equivalent to the difference in thickness. Also, when comparing Sample 4 and Sample 5, the difference in the force required for bending is about 1.3 times, and the difference in thickness is about 1.4 times, so this is also equivalent to the difference in thickness. Therefore, the bending force is proportional to the thickness difference. Also, when comparing the samples, as shown in Fig. 26, it was confirmed that the thinner the exterior body, the lower the force required for bending. For example, when comparing Sample 3 and Sample 5 at a displacement of 4 mm, the difference in the force required for bending is about twice, which is equivalent to the difference in thickness. Also, when comparing Sample 4 and Sample 5, the difference in the force required for bending is about 1.3 times, and the difference in thickness is about 1.4 times, so this is also equivalent to the difference in thickness. Therefore, the bending force is proportional to the thickness difference. It was confirmed that the force required for bending tends to be proportional to the thickness of the film used for the exterior body. .

[0250] From the above, it was confirmed that the battery according to one aspect of the present invention is a battery in which the force required for bending is extremely small by using a corrugated film for the exterior body. Furthermore, it was confirmed that by making the exterior body thinner, it becomes possible to bend with a smaller force. Furthermore, it was confirmed that by making the exterior body thinner, it becomes possible to bend with a smaller force.

Example

[0251] In this example, a band for a wristwatch incorporating a battery according to one aspect of the present invention was produced.

[0252] First, the method for producing the band will be described. The band was produced by the following method. The method for producing the band will be described with reference to FIG. 27.

[0253] First, with a molding material sandwiched between the lower mold and the first upper mold, the lower mold and the first upper mold were pressed together so as to be pressed, and the molding material was cured with the lower mold and the first upper mold combined to produce a lower molded body (FIGS. 27(A) and (B)). Here, as shown in FIG. 27(B), a groove portion was formed in a part of the lower molded body. Thereby, a lower molded body was produced (FIGS. 27(A) and (B)). Here, as shown in FIG. 27(B), a groove portion was formed in a part of the lower molded body.

[0254] Subsequently, the first upper mold was removed, and the battery was installed so as to be fitted into the groove portion of the lower molded body (FIG. 27(C)).

[0255] Thereafter, with a molding material disposed between the battery and the second upper mold, the second upper mold and the lower mold were pressed together so as to be pressed, and the molding material was cured with the second upper mold and the lower mold combined (FIG. 27(D)).

[0256] Thereafter, by removing the second upper mold and the lower mold, a band incorporating the battery was produced (FIG. 27(E)). 7(E))。

[0257] In this embodiment, a sample 6 using a millable silicone raw material as the molding material and a sample 7 using a liquid silicone raw material were each prepared. Also, for sample 6, a battery manufactured in the same manner as sample 3 described in Example 4 was used, and for sample 7, one manufactured in the same manner as sample 5 exemplified in Example 4 was used respectively. Liquid silicone raw material was used to prepare each of the samples 7. Also, for sample 6, a battery manufactured in the same manner as sample 3 described in Example 4 was used, and for sample 7, one manufactured in the same manner as sample 5 exemplified in Example 4 was used respectively. The battery prepared in the same manner as sample 3 described in Example 4 was used for sample 6, and for sample 7, one prepared in the same manner as sample 5 exemplified in Example 4 was used respectively. The battery prepared in the same manner as sample 3 described in Example 4 was used for sample 6, and for sample 7, one prepared in the same manner as sample 5 exemplified in Example 4 was used respectively.

[0258] Fig. 28(A) shows a photograph of the upper surface of sample 6. It can be seen that a battery is built into the milky white silicone rubber. Also, Fig. 28(B) is a photograph when the part where the battery of the band is located is bent. Fig. 28(A) shows a photograph of the upper surface of sample 6. It can be seen that a battery is built into the milky white silicone rubber. Also, Fig. 28(B) is a photograph when the part where the battery of the band is located is bent. Fig. 28(A) shows a photograph of the upper surface of sample 6. It can be seen that a battery is built into the milky white silicone rubber. Also, Fig. 28(B) is a photograph when the part where the battery of the band is located is bent.

[0259] Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force. Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force. Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force. Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force. Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force. Figs. 29(A) and (B) show photographs of the upper surface and the side surface of sample 7. Although the rubber molded body of sample 7 is a darker milky white than that of sample 6 and is slightly transparent, it can be confirmed that the corrugated shape of the exterior body of the built-in battery is maintained without being crushed. Also, Fig. 29(C) is a photograph when the part where the battery of the band is located is bent. Since the thickness of the film used for the exterior body of sample 7 is thinner than that of sample 6, it has been confirmed that the flexibility is improved and it can be bent with a weak force.

[0260] As described above, by molding rubber so as to cover the exterior body, a rubber molded body incorporating a battery can be manufactured for one aspect of the present invention. Here, a shape assuming a watch band was manufactured, but it is not limited to this and can be applied to any rubber molded body. As described above, by molding rubber so as to cover the exterior body, a rubber molded body incorporating a battery can be manufactured for one aspect of the present invention. Here, a shape assuming a watch band was manufactured, but it is not limited to this and can be applied to any rubber molded body. As described above, by molding rubber so as to cover the exterior body, a rubber molded body incorporating a battery can be manufactured for one aspect of the present invention. Here, a shape assuming a watch band was manufactured, but it is not limited to this and can be applied to any rubber molded body.

Example

[0261] In this example, a battery of one aspect of the present invention was manufactured, and the results of a bending and stretching test were will be described.

[0262] In this embodiment, the following three types of samples 8, 9, and 10 were prepared.

[0263] The outer packages used for each of samples 8, 9, and 10 were aluminum laminate films in which polypropylene, aluminum foil, and nylon were laminated in that order, and films with an aluminum foil thickness of about 20 μm and a total thickness of 50 μm were used. Also, the processed films were used where the pitch of the waves was 2 mm and the height difference between the convex surface and the concave surface was 0.5 mm.

[0264] Samples 8, 9, and 10 were prepared using the same method as in Example 1, except that the film folding method was different.

[0265] Sample 8 was obtained by folding the film so that the phase of the waves was shifted by 180 degrees, that is, the ridge lines and valley lines of the waves overlapped each other.

[0266] Sample 9 was obtained by folding the film so that the phases of the waves did not match. Specifically, the phase of the waves was shifted by about 90 degrees

[0267] Sample 10 was obtained by folding the film so that the phases of the waves matched, that is, one ridge line and the other valley line overlapped each other.

[0268] Transmission X-ray photographs of samples 8, 9, and 10 are shown in FIGS. 30(A), (B), and (C), respectively. It can be seen that although there are some portions where the phases of the waves of the pair of films are slightly shifted due to the film bonding process, the generally desired shape has been obtained.

[0269] Subsequently, bending tests were conducted on each of Sample 8, Sample 9, and Sample 10. The test was repeated 10,000 times for bending and stretching operations between a radius of curvature of 40 mm (bending) and a radius of curvature of 150 mm (stretching).

[0270] Appearance photos of each sample after the bending and stretching test are shown in FIGS. 31(A), (B), and (C).

[0271] As shown in FIG. 31(A), no significant change was observed in the appearance of Sample 8 even after the bending test. In addition, as shown by the broken line in FIG. 31(B), there was a portion in the side seal part of Sample 9 where deformation was observed, but no leakage of the electrolytic solution occurred. On the other hand, in Sample 10, as shown by the broken line in FIG. 31 (C), a largely distorted portion was observed in the side seal part. Also, in Sample 10, leakage of the electrolytic solution was confirmed after 10,000 bending tests. (C), a largely distorted portion was observed in the side seal part. Also, in Sample 10, leakage of the electrolytic solution was confirmed after 10,000 bending tests.

[0272] From the above, it was confirmed that deformation of the side seal part was less likely to occur under the conditions where the phase of the film waves was shifted (Samples 8 and 9) compared to the conditions where the phase of the film waves was matched (Sample 10). In particular, under the condition where the phase of the film waves was shifted by 180 degrees (Sample 8), almost no deformation was observed in the side seal part, and good results were obtained. almost no deformation was observed in the side seal part, and good results were obtained.

[0273] Subsequently, the amount of moisture infiltration into the film was measured for Samples 8 and 9, and the sealing performance was evaluated. The measurement of the amount of moisture infiltration was carried out by the same method as in Example 3. Note that for Sample 1 0, since leakage of the electrolytic solution was observed as described above, no evaluation was performed. Also, for Samples 8 and 9, two samples prepared under the same conditions and subjected to bending tests were evaluated

[0274] ​​​​ FIG. 32 shows the measured amount of moisture penetration.

[0275] In sample 8, the amount of moisture penetration was less than 100 ppm for all samples, and 1000 ppm for all samples. It was confirmed that good sealing performance was maintained even after 0 bending tests. Although the aluminum foil of Sample 8 is a thinner film than that of the sample shown in Example 3, It was confirmed that the sealing performance was equivalent regardless of the material.

[0276] On the other hand, the amount of moisture penetration in sample 9 was greater than that in sample 8. This is because B) From the external appearance photograph, there is a part near the side seal that is prone to localized deformation. Therefore, repeated deformation of the part in question may cause metal fatigue, resulting in cracking of the aluminum foil. This is believed to be the result of the formation of a rack and the deterioration of sealing performance. It is presumed that the aluminum foil is extremely thin compared to Example 3, which resulted in a significant difference in sealing performance. can be.

[0277] In addition, the high-temperature, high-pressure water treatment in the pressure cooker used in this test is a harsher environment than the practical range. The test was conducted under mild conditions, and the bending test did not result in leakage of electrolyte from sample 9. It is assumed that sufficient sealing performance for practical use has been secured.

[0278] From the above results, it can be concluded that the bending and stretching motions are repeated under the condition that the phase of the film wave is shifted. It was confirmed that there was no problem such as electrolyte leakage even if the film was folded. It was confirmed that there was almost no deterioration in sealing performance when the phase was shifted by 180 degrees. In other words, the closer the film wave phase is to a 180 degree shift, the greater the bending and stretching. It can be said that this increases the resistance to repeated bending.

Example

[0279] In this example, when the battery is bent, the deformation of the film exterior with a wave shape is calculated. The results will be described.

[0280] Two models (Model1, Model2) were used for the calculation. Model1 is shown in Fig. 3 3 (A1), (A2), and Model2 is shown in Fig. 33 (B1), (B2), respectively. Fig. 33 (A1), (B1) are perspective views of Model1 and Model2, respectively, and Fig. 33 (A2), (B2) are views of Model1 and Model2 seen from the lateral direction, respectively.

[0281] The calculation model will be described. First, as the battery exterior, a structure was assumed in which two films with a wave shape are arranged with a space in between and adhered at the end portions in the width direction. As the material properties of the film, values calculated from the results of the tensile test of the aluminum laminate film obtained in Example 2 were used, with a Young's modulus of 4.9×10 Pa, a yield stress of 2×10 Pa, a tangent modulus of 6. 3×10 9 Pa, and a Poisson's ratio of 0.3. For the simplification of the calculation structure, a structure without an electrode laminate layer inside was adopted. 7 Pa, a tangent modulus of 6. 3×10 7 Pa, and a Poisson's ratio of 0.3. For the simplification of the calculation structure, a structure without an electrode laminate layer inside was adopted. layer is adopted.

[0282] The battery exterior of Model1 is such that a pair of films are arranged with a 180-degree phase shift of the waves, and the battery exterior of Model2 is such that a pair of films are arranged with the waves having the same phase. The battery exterior of Model2 is such that a pair of films are arranged with the waves having the same phase. arranged.

[0283] It was assumed that the battery exterior deforms along the surface of a rigid body. The rigid body is curved with a radius of curvature of 25 mm. It has the following surface. For convenience in calculation, a part of the rigid body is made into a comb blade shape to set the contact conditions at the contact part between the edge line of the battery and the rigid body. Also, a cylindrical rigid body is arranged near the end of the battery, and the battery is deformed by displacing it in the vertical direction as indicated by the arrow in Fig. 33(A2) etc.

[0284] For the calculation, ANSYS Mechanical APDL 14.0 manufactured by ANSYS was used. As the mesh condition of the calculation model, element type: 285 (3D 4-node tetrahedron solid) was used.

[0285]

[0286] The calculated stress values showed no significant difference between Model1 and Model2.

[0287] Figs. 34(A) and (B) show the deformed shapes in Model1, and Figs. 35(A) and (B) show the deformed shapes in Model2. Figs. 34(A) and 35(A) correspond to Figs. 33(A2) and (B2) respectively, and Figs. 34(B) and 35(B) correspond to Figs. 33(A2) and (B2) when viewed from the opposite side (back side).

[0288] Focusing on the shape after bending, it was found that in Model1, each part deformed evenly corresponding to the bending, while in Model2, there was significant distortion. Specifically, in Figs. 34(A) and (B) showing the calculation results of Model1, symmetrical shapes are shown, while in Figs. 35(A) and (B) showing the calculation results of Model2, an asymmetrical shape can be confirmed. In particular, when viewed from the side of Fig. 35(A), the front side of the battery exterior is the rigid body. ​​​​​​​​​​​​It can be seen that it is deformed into a shape that rises from the surface and is in a twisted shape.

[0289] Here, in the battery exterior, a pair of films are fixed at the side seal part. The side seal part is located on the substantially neutral plane of the battery exterior. Therefore, when the battery exterior is bent, the side seal part does not expand or contract, and the wavy part located between the pair of side seal parts mainly deforms into a wave shape.

[0290] Also, focusing on one of the films, when the film is bent, the film deforms starting from the valley line part close to the neutral plane. The ridge line part sandwiched between the two valley line parts deforms following the deformation of the two valley line parts located on both sides of it. Therefore, the pair of films each deform starting from the valley line part. Therefore, it is presumed that the part sandwiched between the two valley line parts close to each other across the neutral plane is the part that is most likely to deform. In Model1, since the phase difference of the waves is 180 degrees, the distance between the two valley line parts close to each other across the neutral plane is the shortest, and it has a structure that is easy to bend. Moreover, in Model1, when the battery exterior is viewed from the lateral direction, the straight line connecting the two valley line parts close to each other across the neutral plane passes through the center of bending respectively. Therefore, as shown in FIGS. 34(A) and (B), it is presumed that Model1 is deformed into a shape with less distortion.

[0291] On the other hand, in Model2, since the phases of the waves coincide, the distance between the two valley line parts close to each other across the neutral plane is the longest, and it has a structure that is difficult to bend.

[0292] Furthermore, in Model2, when the battery exterior is viewed from the lateral direction, the straight line connecting the two valley line parts close to each other across the neutral plane passes through the center of bending respectively. Therefore, as shown in FIGS. 34(A) and (B), it is presumed that Model1 is deformed into a shape with less distortion. (B), it is presumed that Model1 is deformed into a shape with less distortion.

[0293] On the other hand, in Model2, since the phases of the waves coincide, the distance between the two valley line parts close to each other across the neutral plane is the longest, and it has a structure that is difficult to bend.

[0294] Furthermore, in Model 2, when focusing on one valley line portion, the closest valley line portions located on the opposite sides across the neutral plane will be two. That is, there are two most deformable portions corresponding to one valley line portion. Also, when viewing the battery exterior from the lateral direction, there are two straight lines connecting one valley line portion and the closest valley line portion thereto, but neither passes through the bending center and intersects at the valley line portion, which is also a difference from Model 1. The two most deformable portions corresponding to the above-mentioned one valley line portion do not deform to the same extent, but it is expected that one of them will deform more significantly. However, since it is not uniquely determined which one is more deformable, when the battery exterior is bent, there may occur a portion where both of the two most deformable portions are deformed significantly locally. The portions with large strain shown in FIGS. 35(A) and (B) are considered to correspond to this.

[0295] Also, as shown in Example 6, this is in good agreement with the result that Sample 10 with the wave phases matched had a portion with large strain formed at the side seal portion by the bending and stretching test. From the above, as shown in Model 2, the structure of the battery exterior with the wave phases completely matched cannot be said to be a shape suitable for bending, and it can be seen that a structure with the wave phases shifted is desirable. Furthermore, as shown in Model 1, the structure of the battery exterior with the wave phases shifted by 180 degrees can be said to be the most desirable form.

[0296]

[0297]

Explanation of Reference Numerals

[0297] 10 Battery 11 Exterior body 12 Laminate 13 Electrode 13a Electrode 13b electrode 21 ridge line 21a ridge line 21b ridge line 22 valley line 22a valley line 22b valley line 25 space 31 part 31a part 31b part 32 bending part 33 joint part 34 joint part 41 electrode 42 electrode 43 electrode 50 film 51 mold 52 mold 53 mold 54 mold 55 embossing roll 55a convex part 56 embossing roll 56a convex part 57 roll 60 advancing direction 61 film 62 film 63 convex part 64 space 71 region 72 positive current collector 73 separator 74 negative current collector 75 sealing layer 76 lead electrode 77 electrolyte 78 positive active material layer 79 negative active material layer 80 plane 90 plane 7100 mobile phone 7101 housing 7102 display part 7103 operation button 7104 secondary battery 7105 lead electrode 7106 current collector 7400 mobile phone 7401 housing 7402 display unit 7403 operation button 7404 external connection port 7405 speaker 7406 microphone 7407 secondary battery 7408 lead electrode 7409 current collector 7600 vacuum cleaner 7601 lead electrode 7602 lead electrode 7603 operation button 7604 secondary battery 7605 secondary battery 7606 display unit 8021 charger 8022 cable 8100 automobile 8101 headlight 8200 automobile

Claims

1. A method for manufacturing a battery having a laminate inside an exterior body, comprising: a first step of preparing the film-like exterior body that is processed into a wavy shape in which a plurality of ridge lines and a plurality of valley lines parallel to each other are alternately positioned and the plurality of ridge lines are equally spaced; a second step of folding a part of the exterior body 180 degrees in a direction perpendicular to the ridge lines and the valley lines to sandwich the laminate; a third step of joining another part of the exterior body, which is located outside the laminate and extends in a direction perpendicular to the ridge lines and the valley lines, in a band shape; In the third step, joining is performed so that a part of the exterior body becomes flat, and in a portion of the exterior body that overlaps the laminate, the exterior body is joined so that the interval between the plurality of ridge lines widens as it gets closer to the folded part of the exterior body; A method for manufacturing a battery.

2. In Claim 1, after the first step and before the second step, there is a fourth step of processing the exterior body so that a band-shaped portion extending in a direction parallel to the ridge lines and the valley lines of the exterior body becomes flat; In the second step, folding the flat processed portion of the exterior body; A method for manufacturing a battery.

3. In Claim 1 or Claim 2, In the second step, folding the exterior body while shifting the ridge lines and valley lines of the folded and overlapping exterior body so that they do not overlap; A method for manufacturing a battery.

4. In any one of Claims 1 to 3, In the second step, folding the exterior body so that the ridge lines of the folded and overlapping exterior body overlap each other and the valley lines overlap each other; A method for manufacturing a battery.

Images