Secondary battery

Abstract

To provide a battery whose shape can be changed safely, or to provide a battery that can be repeatedly bent.SOLUTION: Provided is a battery having a first lead, a second lead, a first current collector, and a second current collector. The first current collector has: a first portion bonded with the first lead; and a second portion coated with a first active material. The second current collector has: a third portion bonded with the second lead; and a fourth portion coated with a second active material. The first lead, the second portion, and the fourth portion have portions overlapped with each other. The second lead, the second portion, and the fourth portion have portions overlapped with each other.SELECTED DRAWING: Figure 8

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 the internal structure of 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 memory device, and the like. , electronic device, lighting device, input device, input / output device, driving method thereof, or manufacturing method thereof The law can be cited as an example. [Background technology]

[0003] Mobile information terminal devices, such as smartphones and tablet devices, are being actively developed. In addition, such electronic devices are required to be lightweight and small. .

[0004] In particular, in recent years, the development of wearable electronic devices has become more widespread. Examples of wearable devices include wristwatch-type devices worn on the arm and head-mounted devices. Examples include goggle-type or goggle-type devices, and necklace-type devices worn around the neck. For example, a wristwatch-type device has a small display instead of the dial of a conventional watch. This allows the user to receive various information other than the time. The device is also attracting attention for its medical applications and self-management of health status, and is being put into practical use. .

[0005] Portable devices often have secondary batteries that can be repeatedly charged. Rechargeable devices use small secondary batteries, which are lightweight, small, and have a long life. It is required that time be available.

[0006] Patent Document 1 describes a highly flexible device that uses a thin, flexible film-like material as an exterior. A battery is disclosed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2012 / 140709 Summary of the Invention [Problem to be solved by the invention]

[0008] In portable devices, the battery occupies a large proportion of the device's volume. By using a battery that can be mounted in a limited space inside the housing, This allows for miniaturization of the device. Until now, it has been difficult to place batteries in moving parts of equipment, but If this battery can be realized, it will be possible to create devices with better designs.

[0009] However, secondary batteries are prone to overheating and fire if the exterior is damaged. Even when a film is used for the packaging, it is generally covered with a hard outer packaging. However, this structure does not assume that the secondary battery will be bent or otherwise deformed. When the device is installed in a slave device, there is a problem in that the location where the device can be installed is limited.

[0010] Furthermore, when conventional secondary batteries are repeatedly bent, not only are the exterior bodies damaged, but the electrodes inside the exterior bodies are also damaged. There was a risk of short circuits between electrodes or damage to the electrodes themselves, which posed safety issues.

[0011] An object of one embodiment of the present invention is to provide a battery that can be safely deformed. Another object is to provide a battery that can be repeatedly bent.

[0012] Another object of one embodiment of the present invention is to provide a battery with a large capacity per volume. Another object of the present invention is to provide a highly reliable battery.

[0013] The description of these problems does not preclude the existence of other problems. It is not necessary to solve all of these problems. It is possible to extract issues other than those mentioned above. [Means for solving the problem]

[0014] One aspect of the present invention is a semiconductor device including a first lead, a second lead, a first current collector, and a second current collector. The first current collector has a first portion joined to the first lead, and a second portion joined to the first lead. The second current collector has a second portion coated with the first active material. The second current collector is joined to a second lead. The first lead has a third portion coated with a second active material and a fourth portion coated with a second active material. The second portion and the fourth portion have overlapping portions, and the second lead and the second The first portion and the fourth portion have overlapping portions.

[0015] In the above, it is preferable that an insulating fixing member is provided. The board, the first current collector, and the second current collector are fixed by a fixing member at their overlapping portions. The second lead, the first current collector, and the second current collector are fixed by a fixing member at their overlapping portions. It is preferable that the substrate is fixed by a metal plate.

[0016] In the above, the first current collector is folded back between the first portion and the second portion, The first lead, the first portion, and the second portion preferably have overlapping portions. The second current collector is folded back between the third and fourth portions, and the second lead It is preferable that the first portion, the third portion, and the fourth portion have overlapping portions.

[0017] In the above, the first current collector is arranged so that the surface to be joined with the first lead faces outward. The second current collector is folded back so that the surface to be joined with the second lead faces outward. It is preferable that

[0018] In the above, it is preferable to have a first insulating member and a second insulating member. At this time, the first portion and the second portion overlap with each other via the first insulating member, and the third portion The first and fourth portions preferably overlap with each other via the second insulating member. The edge member covers the first portion and the first lead, and the second insulating member covers the third portion and the second lead. It is preferable to cover the leads.

[0019] In the above, it is preferable that the device has an exterior body. In this case, the exterior body is a film The electrode has a rectangular shape and is folded in two so as to sandwich the first current collector and the second current collector. The outer casing is preferably a pair of first shields sandwiching the first current collector and the second current collector. and a second seal portion overlapping the first lead and the second lead. In addition, the outer casing has a second current collector in a region overlapping with the first current collector and the second current collector. It is preferable that the sealing portion has a wave shape that is approximately parallel to the sealing portion.

[0020] In the above, the first seal portion and the second seal portion are flat and do not have a corrugated shape. It is preferable that there is.

[0021] In the above, the first seal portion and the end of the first current collector or the end of the second current collector The distance between the first current collector and the second current collector is 0.8 times or more and 3.0 times or less than the thickness of the laminate including the first current collector and the second current collector. It is preferable that the ratio is 1:1 or less.

[0022] In the above, the distance between the pair of first seal portions and the width or the width of the first current collector are The difference between the width of the first current collector and the width of the second current collector is 1.6 times the thickness of the laminate including the first current collector and the second current collector. It is preferable that the ratio is 6.0 or more.

[0023] Another aspect of the present invention is a semiconductor device including a first current collector, a second current collector, a first lead, and a second A method for producing a battery having a lead, comprising: a step, a first current collector and a first lead, and a second current collector and a second lead, a second step of bonding the first current collector, the second current collector, the first lead, and the second lead together; and a third step of fixing the board with a fixing member.

[0024] In the above, between the second step and the third step, a part of the first current collector is and a fourth step of folding back a portion of the second current collector.

[0025] In addition, in the above, instead of the first step, a plurality of first current collectors and a plurality of second current collectors are The fifth step preferably comprises the following fifth step of stacking a plurality of conductive bodies. A stack of first current collectors offset from one another and a plurality of second current collectors offset from one another. It's Tep. [Effects of the Invention]

[0026] According to one aspect of the present invention, a battery that can be safely deformed can be provided. It is possible to provide a battery that can be repeatedly bent. Or, it is possible to provide a battery with a large capacity per volume. We can provide highly reliable batteries. [Brief explanation of the drawings]

[0027] [Figure 1] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 2] 1 shows a current collector according to an embodiment. [Figure 3] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 4] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 5] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 6] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 7] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 8] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 9] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 10] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 11] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 12] 1A to 1C illustrate a method for manufacturing a battery according to an embodiment. [Figure 13] 1 shows an example of the configuration of a battery according to an embodiment. [Figure 14] 1 shows an example of the configuration of a battery according to an embodiment. [Figure 15] 1. An electronic device according to an embodiment. [Figure 16] 1. An electronic device according to an embodiment. [Figure 17] 1 is a photograph of the appearance of Example 1. [Figure 18] 1 is a photograph of the appearance of Example 1. [Figure 19] 1 is a photograph of the appearance of Example 1. [Figure 20] 1 is a photograph showing the appearance of a battery according to Example 1. [Figure 21] 10 is a transmission X-ray image of a battery according to Example 2. [Figure 22] 10 is a transmission X-ray image of a battery according to Example 2. [Figure 23] 10 is an X-ray CT image of a battery according to Example 2. [Figure 24] 5 shows charge and discharge characteristics of a battery according to Example 2. [Figure 25] 5 shows charge and discharge characteristics of a battery according to Example 2. [Figure 26] 5 shows charge and discharge characteristics of a battery according to Example 2. [Figure 27] 10 is a transmission X-ray image of a battery according to Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0028] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. The present invention is not limited to the above embodiments, and various changes and modifications may be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention is based on the following embodiments. The present disclosure should not be construed as being limited to the contents of the preceding paragraph.

[0029] In the configuration of the invention described below, the same parts or parts having similar functions are The same reference numerals are used in common between different drawings, and repeated explanations thereof will be omitted. When referring to a function, the hatch pattern may be the same and no particular symbol may be assigned.

[0030] In each figure described in this specification, the size, layer thickness, or area of ​​each component is The figures may be exaggerated for clarity and are not necessarily limited to that scale. stomach.

[0031] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components. The number is not a numerical limitation.

[0032] (Embodiment 1) In this embodiment, a structural example and a manufacturing method example of a battery according to one embodiment of the present invention will be described. .

[0033] The battery according to one embodiment of the present invention includes a first current collector and a second current collector disposed inside a film-like outer casing. The first current collector is either a positive electrode current collector or a negative electrode current collector. The second current collector is the other of the positive electrode current collector and the negative electrode current collector. Each lead has a pair of leads extending from the inside to the outside of the outer casing. Each is bonded to the first current collector or the second current collector.

[0034] The first current collector and the second current collector each have a protruding portion (also called a tab portion) in a plan view. The tab portion has a joining portion (also called a first portion) to which the lead is joined. In addition, the first current collector and the second current collector have a portion coated with an active material (electrode portion, or (also referred to as the second portion).

[0035] In this specification and the like, the configuration contained inside the exterior body is referred to as an electrode laminate, a laminate, or an electrode. The electrode stack is sometimes called an electrode member. The electrode stack is made up of at least a first current collector and a second current collector. The electrode laminate also includes a lead joined to the first current collector, and a second current collector. The electrode stack may include a lead to be joined to the first current collector and the second current collector. A separator and an electrolytic solution may be provided between the electrodes. In this case, the separator may not be provided.

[0036] The battery may also have a plurality of first current collectors and a plurality of second current collectors. The more current collectors that are connected, the greater the capacity of the battery.

[0037] One aspect of the present invention is a lead, a second portion of the first current collector, and a second portion of the second current collector. The lead and the first current collector have portions that are fixed to each other by a fixing member. The body is not only joined at the part where the tab overlaps, but is also fixed at the part other than the tab. Similarly, the lead and the second current collector are further fixed at a portion other than the tab portion.

[0038] Here, the lead and the first current collector are fixed only by the tab portion, and the lead and the second current collector are fixed by the tab portion. Consider the case where the battery is fixed only by the tab. When the first current collector and the second current collector are rotated, they are also repeatedly deformed. In the current collector, the tab portion is a portion where the active material layer is not coated, and is thicker than the other portions. The tab portion is thinner than the second portion coated with the active material layer. The tab portion has lower mechanical strength than the other parts of the current collector. Therefore, the first current collector and the second current collector are repeatedly deformed. This can easily cause cracks in the tabs and their bases. In this case, the tab portion may break.

[0039] Therefore, in one aspect of the present invention, a lead is formed between the first current collector or the second current collector through the tab portion. The lead and the second part of the current collector are fixed together using a fixing member. This makes it possible to achieve a structure in which the tab section is less likely to deform. No matter what kind of deformation is applied, it is difficult for problems to occur, and a highly reliable battery can be realized.

[0040] In addition, the first current collector and the second current collector are fixed by the fixing member. It is preferable that the battery is not fixed to each other. This prevents the battery from being bent by the fixing member. The current collectors shift relative to each other, with the fixed part as a fulcrum, and the stress on each current collector increases. This reduces the risk of damage to the current collectors. This allows bending with less force.

[0041] As an example of a preferred configuration, the tab portions of the first current collector and the second current collector are connected to the lead. The area between the joint and the electrode portion where the active material is applied is folded back. A part of the tab portion including the joint portion (first portion) of the first current collector and the second current collector, and a part of the lead The part and the electrode part (second part) are fixed by a fixing member.

[0042] Here, it is preferable that the tab portion is folded back in a curved state rather than bent. For example, the radius of curvature is 5 times or more, preferably 10 times or more, more preferably 10 times or more, the thickness of the tab portion. It is preferable that the tab portion is bent at least 20 times and less than 50 times. Depending on the material of the current collector, the radius of curvature of the folded part may be less than five times the thickness of the tab. In this case, the tab may break when folded back. Also, if the curvature radius is too large ( For example, if the capacity is increased by more than 50 times, the thickness of the battery will become too large.

[0043] When the tab portion is folded back, the tab portion of one current collector and the other current collector having a different polarity are If the current collectors on the other side come into contact with each other, an electrical short may occur. It is preferable to insulate a part of the surface of the current collector. It is preferable to sandwich an insulating member between the tab portion and the insulating member. is more preferred.

[0044] In addition, when the tab is folded back, it should be folded so that the surface that is bonded to the lead faces outward. It is preferable to repeat the process.

[0045] In another preferred embodiment, the lead is connected to the tab portion. The lead has a shape that extends to the electrode portion. These may be fixed by a fixing member.

[0046] The exterior body covering the first current collector and the second current collector has a plurality of periodically connected electrodes in one direction. It is preferable to use a corrugated film that is connected to the exterior body. The stress caused by bending is alleviated by deformation that changes the wave period and amplitude, and the exterior It can prevent the body from being damaged.

[0047] In addition, one side of the exterior body is folded so as to sandwich the first current collector and the second current collector, The seal is formed by crimping the remaining three sides of the first current collector and the second current collector. In this case, the part that overlaps with the lead is called the top seal part, The other portion can be called a side seal portion.

[0048] At this time, the width direction of the first current collector or the second current collector (the direction parallel to the top seal portion) By providing a gap between the end of the first seal and the side seal, the battery can be prevented from bending repeatedly. This can prevent the current collector or the second current collector from rubbing against the exterior body. The distance between the first current collector or the second current collector and the side seal portion is The thickness of the laminate is 0.8 times or more, preferably 0.9 times or more, more preferably 1.0 times or more, the thickness of the laminate is 0.8 times or more, more preferably 1.0 times or more, the thickness of the laminate is 0.9 times or more, more preferably 1.0 times or more, the thickness of the laminate is 0.8 times or more, It is preferable that the ratio is 1.0 or more and 3 times or less, and more preferably 2 times or less. Alternatively, for example, the distance between the pair of side seals and the width of the first current collector or the second current collector may be The difference is preferably 1.6 times or more the thickness of the laminate obtained by laminating the first current collector and the second current collector. It is preferably 1.8 times or more, more preferably 2.0 times or more, and 4 times or less. stomach.

[0049] In addition, the end of the first current collector or the second current collector in the width direction and the side seal of the exterior body are To create gaps between the parts, the shape of the exterior body is molded in advance (also called pre-molding). It is preferable that the preforming step is carried out, for example, before the step of forming the side seal. The position where the first current collector overlaps with the end of the first current collector in the width direction and the position where the second current collector overlaps with the end of the first current collector in the width direction are to be side-sealed in a later process. The exterior body may be press-molded so as to provide a gentle curve between the outer casing and the outer casing.

[0050] For example, if preforming is not performed, the first current collector may be formed, for example, when forming the side seal. Or, a portion where the exterior body is bent is formed with the end of the second current collector in the width direction as a fulcrum. On the other hand, when the above-mentioned preformed exterior body is used, the side seal is formed. This makes it difficult for such bent portions to form. It is possible to more effectively prevent the current collector or the second current collector from rubbing against the exterior body, A battery with high resistance to deformation such as repeated bending can be realized.

[0051] A more specific example will be described below with reference to the drawings.

[0052] [Production method example 1] An example of a method for manufacturing a battery according to one embodiment of the present invention will be described below. 2 is a flowchart showing a method for manufacturing the battery shown in FIG.

[0053] [About the current collector] First, a current collector included in a battery of one embodiment of the present invention will be described. 1A and 1B show schematic top views of current collector 11a and current collector 11b, respectively.

[0054] One of the current collectors 11a and 11b serves as a positive electrode current collector and the other serves as a negative electrode current collector. In this embodiment, the current collector 11a is used as a negative electrode current collector, and the current collector 11b is used as a positive electrode current collector. Used as an electrical conductor.

[0055] The current collector 11a has a tab portion 21a and an electrode portion 22a that functions as an electrode of the battery. The tab portion 21a is a protruding portion of the current collector 11a and has a width smaller than that of the electrode portion 22a. The electrode portion 22a is coated with an active material layer 13a.

[0056] The current collector 11b has a tab portion 21b and an electrode portion 22b that functions as an electrode of the battery. The tab portion 21b is a protruding portion of the current collector 11b and has a width smaller than that of the electrode portion 22b. The electrode portion 22b is coated with an active material layer 13b.

[0057] Here, the current collector 11a and the current collector 11b have an active material layer 13a or an active material layer 13b on only one surface. Preferably, the first surface is coated with a layer 13b and the other surface is uncoated.

[0058] Here, it is preferable that the width Wa of the current collector 11a and the width Wb of the current collector 11b are different from each other. In FIGS. 2(A) and 2(B), the width Wa of the current collector 11a is larger than the width Wb of the current collector 11b. This shows an example of a case where

[0059] This concludes the description of the current collector.

[0060] Next, a method for manufacturing a battery will be described with reference to the flowchart shown in FIG. 1 and FIGS. 3 to 8. I will explain.

[0061] [Step S01] First, a plurality of current collectors 11a and 11b are prepared and stacked while being shifted in the length direction. do.

[0062] FIG. 3(A) is a perspective schematic diagram showing the laminated structure. The active material layer 13a and the active material layer 13b are not shown.

[0063] FIG. 3(A) shows an example in which four current collectors 11a and four current collectors 11b are used. Two current collectors 11a are arranged on the outside, and a pair of current collectors 11b and a pair of current collectors 11c are arranged on the inside. The current collectors 11a are arranged alternately. The surfaces of the layers 13a (not shown) opposite to the coated surfaces are arranged in contact with each other. The pair of current collectors 11b are arranged such that the surfaces opposite to the coated surfaces of the active material layer 13b (not shown) face each other. That is, the active material is arranged between the current collector 11a and the current collector 11b. The active material layer 13a and the active material layer 13b are located between two adjacent current collectors 11a and between two adjacent collectors 11b. The active material layer is not provided between the current collectors 11b. When the current collectors 11a and 11b are in the same position, the pair of current collectors 11a and 11b can be easily displaced from each other. As will be described later, the current collectors of the same polarity slide against each other, preventing the current collectors from sliding when the battery is bent. This can reduce the stress on the device itself.

[0064] As shown in FIG. 3(A), a broken line is formed between the current collector 11a and the current collector 11b. A separator 14 may be disposed. The separator 14 has a width greater than that of the current collector 11b. It is preferable to use the following.

[0065] Here, the laminated structure is not limited to the configuration shown in FIG. As shown in FIG. 1, separators 14 are disposed on the outer sides of the two outermost current collectors 11a. This can prevent the current collector 11a from coming into contact with the exterior body described later. Therefore, it is possible to prevent the exterior body from being damaged due to friction between the exterior body and the current collector 11a. In this case, the separator 14 may be wider than the current collector 11a. It is preferable that

[0066] FIG. 4(B) shows an example in which one current collector 11b is provided between two current collectors 11a. Here, the current collector 11b has a structure in which the active material layer 13b is coated on both sides. By adopting such a configuration, the battery can be made thinner, and the The capacity per unit weight can be increased. Furthermore, the current collector 11a has an active material layer 13a (shown in the figure). The pair of current collectors 11 are arranged so that the surfaces opposite to the coated surfaces of the current collectors 11 are in contact with each other. The a's slide easily against each other, which makes it possible to bend the battery with less force.

[0067] FIG. 4(C) shows a configuration in which a pair of current collectors 11b are sandwiched between one separator 14a. Here, the separator 14a is folded back and then joined at its periphery to form a bag shape. By using such a separator 14a, the pair of current collectors 11 Even if misalignment of b occurs, it is possible to prevent an electrical short circuit between the positive electrode and the negative electrode. .

[0068] In FIG. 4(D), the two outermost current collectors 11a are also separators, as compared to FIG. 4(C). As a result, the exterior body and the current collector 11a rub against each other, It can prevent the body from being damaged.

[0069] FIG. 3(B) shows the state in which the current collector 11a and the current collector 11b are stacked. For clarity, the separator 14 is not shown hereinafter.

[0070] As shown in FIG. 3(B), the current collectors 11a are connected to each other, and the current collectors 11b are connected to each other using tabs. The part 21a or the tab part 21b is relatively shifted in the direction (indicated by the arrow) in which the part 21a or the tab part 21b is provided. By arranging them in a shifted position in advance, it is possible to The misalignment that occurs when a part of the current collector 11a and a part of the current collector 11b are bent is offset. Specifically, the positions of the plurality of electrode portions 22a and the electrode portions 22b can be aligned. At this time, the tab portions 21a of all the current collectors 11a are arranged so as to form overlapping portions. Similarly, it is preferable to stack the current collectors 11b in such a manner that the tab portions 21b of all the current collectors 11b overlap each other. It is preferable to laminate the layers so that a layer is formed.

[0071] As shown in FIG. 3(B), the pair of current collectors 11a and the pair of collectors 11b arranged on the inner side The electric conductors 11b do not need to be arranged in a staggered manner.

[0072] [Step S02] Next, as shown in FIG. 3(C), the tab portion 21a of the current collector 11a and the tab portion 21b of the current collector 11b are The leads 12a and 12b are bonded to the tab portions 21b. Sonic welding or the like can be used.

[0073] Here, since the tab portions 21a of the current collectors 11a are arranged in a shifted position, The joint 15a between the tab portion 21a and the lead 12a includes the tab portion 21a of all the current collectors 11a. It is important to set the range to include the tab portion 21b of the current collector 11b and the lead 12b. The same applies to the joint 15b.

[0074] In addition, in FIGS. 3(A), (B), and (C), a plurality of current collectors 11a and 11b are arranged in the same Although an example of the shape is shown, a plurality of current collectors 11a and 11b having different lengths are used. 5(A) and 5(B), the current collector 11a that is longer in the longitudinal direction is closer to the joining surface side. The example shows the case where the tab portion and the current collector 11b are used. Since the tab portions 21a and 21b do not shift in the length direction, the connection of the leads 12a and 12b becomes easy. Also, in FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used. In FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used. In FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used. In FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used. In FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used. In FIGS. 5(A) and (B), the lengths of the tab portion 21a or the tab portion 21b are equal, and the current collectors 11a and 11b with different lengths of the electrode portions 22a or the electrode portions 22b are used. However, as shown in FIG. 5(C), a plurality of current collectors 11a and current collectors 11b with equal lengths of the electrode portions 22a or the electrode portions 22b and different lengths of the tab portion 21a or the tab portion 21b may be used.

[0075] 〔Step S03〕 Subsequently, a part of the tab portion 21a and the lead 12a, and a part of the tab portion 21b and the lead 12b are insulated respectively. Subsequently, a part of the tab portion 21a and the lead 12a, and a part of the tab portion 21b and the lead 12b are insulated respectively.

[0076] FIG. 6(A) is a perspective view of the state where the leads 12a and 12b are joined to the plurality of current collectors 11a and the current collector 11b respectively. FIG. 6(A) is a perspective view of the state where the leads 12a and 12b are joined to the plurality of current collectors 11a and the current collector 11b respectively.

[0077] As shown in FIG. 6(B), by covering a part of the tab portion 21a of the current collector 11a and a part of the lead 12a with the insulating member 16a, the surfaces thereof can be insulated. At this time, it is preferable that the insulating member 16a is provided so as to cover the joint portion 15a. Similarly, a part of the tab portion 21b of the current collector 11b and a part of the lead 12b are covered with the insulating member 16b. As shown in FIG. 6(B), by covering a part of the tab portion 21a of the current collector 11a and a part of the lead 12a with the insulating member 16a, the surfaces thereof can be insulated. At this time, it is preferable that the insulating member 16a is provided so as to cover the joint portion 15a. Similarly, a part of the tab portion 21b of the current collector 11b and a part of the lead 12b are covered with the insulating member 16b. As shown in FIG. 6(B), by covering a part of the tab portion 21a of the current collector 11a and a part of the lead 12a with the insulating member 16a, the surfaces thereof can be insulated. At this time, it is preferable that the insulating member 16a is provided so as to cover the joint portion 15a. Similarly, a part of the tab portion 21b of the current collector 11b and a part of the lead 12b are covered with the insulating member 16b. As shown in FIG. 6(B), by covering a part of the tab portion 21a of the current collector 11a and a part of the lead 12a with the insulating member 16a, the surfaces thereof can be insulated. At this time, it is preferable that the insulating member 16a is provided so as to cover the joint portion 15a. Similarly, a part of the tab portion 21b of the current collector 11b and a part of the lead 12b are covered with the insulating member 16b.

[0078] The insulating member 16a and the insulating member 16b are provided at the portion where the current collectors 11a and the current collectors 11b are folded back later. Thereby, it is possible to prevent the folded-back portion of the current collector 11b from contacting the surface of the current collector 11a and these from being electrically short-circuited. When two current collectors 11a are located on the outermost side as shown in FIG. 6(A) etc., the current collector 11a and the lead 12 The insulating member 16a and the insulating member 16b are provided at the portion where the current collectors 11a and the current collectors 11b are folded back later. Thereby, it is possible to prevent the folded-back portion of the current collector 11b from contacting the surface of the current collector 11a and these from being electrically short-circuited. When two current collectors 11a are located on the outermost side as shown in FIG. 6(A) etc., the current collector 11a and the lead 12 The insulating member 16a and the insulating member 16b are provided at the portion where the current collectors 11a and the current collectors 11b are folded back later. Thereby, it is possible to prevent the folded-back portion of the current collector 11b from contacting the surface of the current collector 11a and these from being electrically short-circuited. When two current collectors 11a are located on the outermost side as shown in FIG. 6(A) etc., the current collector 11a and the lead 12 The insulating member 16a and the insulating member 16b are provided at the portion where the current collectors 11a and the current collectors 11b are folded back later. Thereby, it is possible to prevent the folded-back portion of the current collector 11b from contacting the surface of the current collector 11a and these from being electrically short-circuited. When two current collectors 11a are located on the outermost side as shown in FIG. 6(A) etc., the current collector 11a and the lead 12 a is originally electrically connected, and there is no problem even if they come into contact, so current collection The insulating member 16a on the body 11a side may not be provided.

[0079] As shown in FIG. 6(C), a part of the tab portion 21a of the current collector 11a and the lead 12a A part of the lead 12b is covered with the insulating layer 11b, a part of the tab portion 21b of the current collector 11b, and a part of the lead 12b. A configuration in which an edge member 16 is provided may also be adopted.

[0080] The insulating members 16a, 16b, and 16 are preferably made of polyimide. Insulating tape such as adhesive tape can be suitably used. This prevents the battery from shifting when it is deformed. The insulating material is not limited to this, and may be in various forms such as a bag or a sheet. The material is made by applying a liquid resin material to the surface of the part to be insulated and then hardening it. It may be used.

[0081] The insulating member also prevents electrical short circuit when the tab portion 21a or the tab portion 21b is folded back. The purpose of this is to prevent the electrode part 2 from being broken, and the position where it is placed is not limited to the above. 2a and the electrode portion 22b, or may be attached to a part of the surface thereof. In addition, when the tab portion 21b is folded back, the folded back portion of the tab portion 21b and the current collector 1 An insulating member may be disposed between the electrode 1a and the electrode 1b.

[0082] [Step S04] Next, the tab portions 21a and 21b are folded back.

[0083] At this time, the surface of the tab portion 21a to be joined to the lead 12a and the surface of the tab portion 21b to be joined to the lead 12b are The tab portions 21a and 21b are folded back so that the surfaces to be joined with 2b are positioned on the outside. It is preferable.

[0084] FIG. 7(A) shows the state of the joining portion 15a side when the tab portion 21a and the tab portion 21b are folded back. 7(B) is a perspective view of FIG. 7(A) rotated 180 degrees. For clarity, hereinafter, the insulating members 16a and 16b, or the insulating member 16, are referred to as It is not explicitly stated.

[0085] As shown in FIG. 7(A), a part of the lead 12a and a part of the lead 12b are connected to the current collector 1. The tab portion 21a is positioned so as to overlap the electrode portion 22a of the current collector 11a and the electrode portion 22b of the current collector 11b. It is preferable to bend the tab portion 21b. Similarly, the tab portions 21a and 21b are bent. It is preferable that the electrode portion 22a and the electrode portion 22b are folded so as to overlap each other.

[0086] [Step S05] Next, the leads 12a, 12b, the electrode portions 22a, and the electrode portions 22b are attached to the fixing member 17. Fix it by.

[0087] FIG. 8(A) is a perspective view of the joint 15a side when the fixing member 17 is provided, and FIG. 8B) is a perspective view of FIG. 8A rotated 180 degrees.

[0088] The fixing member 17 can be preferably an insulating tape such as a polyimide tape. The fixing member 17 is not limited to this, and may be a circular rubber (rubber band) or any other suitable material. Alternatively, an insulating material such as a resin material molded into a desired shape may be used.

[0089] In this manner, the electrode member 10 can be produced.

[0090] As shown in FIG. 8A and other figures, the electrode member 10 has a tab portion 21a and a tab portion 21b folded back. The joints 15a and 15b overlap with parts of the electrode parts 22a and 22b. Therefore, compared with a configuration in which the tab portions 21a and 21b are not folded back, Therefore, the battery using the electrode member 10 can be shortened in the longitudinal direction. Because it can be made more compact, the capacity per unit volume can be increased.

[0091] [Step S06] Next, the electrode member 10 is covered with an outer casing together with the electrolyte, and the periphery of the outer casing is sealed (sealed). )do.

[0092] Through the above steps, a battery of one embodiment of the present invention can be manufactured.

[0093] [Production method example 2] Below, an example of a battery manufacturing method that is partially different from the above-mentioned manufacturing method example 1 will be described with reference to the drawings. Here, explanations of parts that overlap with those described above may be omitted.

[0094] FIG. 9 is a flowchart illustrating the manufacturing method exemplified below.

[0095] [Step S11] First, as shown in FIG. 10(A), a plurality of current collectors 11a and 11b are prepared. Unlike the manufacturing method example 1, the pieces are stacked without intentionally shifting. do.

[0096] [Step S12] Next, as shown in FIG. 10(B), the tab portion 21a of the current collector 11a and the current collector 11b The leads 12a and 12b are bonded to the tab portions 21b, respectively.

[0097] At this time, the leads 12a and 12b partially overlap the electrode portions 22a and 22b. The shape should be such that

[0098] [Step S13] Next, in order to prevent an electrical short circuit between the lead 12b and the current collector 11a, An insulating member 18 is provided between them to insulate the lead 12b from the current collector 11a.

[0099] In FIG. 11(A), an insulating member 18 is wound around a part of the current collector 11a and the current collector 11b. An example is shown.

[0100] The configuration of the insulating member 18 is not limited to this, and any other insulating member may be used as long as it can insulate the leads and current collectors of different poles. In FIG. 12(A), the current collector 11a and the lead 12b 12(B) shows an example in which an insulating member 18a is disposed only between the 1 shows an example in which the portion of the lead 12b overlapping with the current collector 11a is covered with an insulating member 18b. In addition, in FIG. 12(C), the portion of the lead 12a overlapping with the current collector 11a, and In this example, the portion of the lead 12b that overlaps with the current collector 11a is sandwiched between an insulating member 18c.

[0101] The insulating member 18, the insulating member 18a, and the insulating member 18b may be the same as the insulating member 16, etc. Similar materials can be used.

[0102] [Step S14] Next, as shown in FIG. 11(B), the leads 12a, 12b, the electrode portion 22a, and the electrode The pole portion 22b is fixed by a fixing member 17.

[0103] In this manner, the electrode member 10a can be produced.

[0104] According to this example of the manufacturing method, there is no step of folding back the tab portions 21a and 21b. This can further improve productivity.

[0105] [Step S15] Next, the electrode member 10a is covered with an outer casing together with the electrolyte, and the periphery of the outer casing is sealed (sealed). (stop).

[0106] Through the above steps, a battery of one embodiment of the present invention can be manufactured.

[0107] The above is a description of an example of a method for producing a battery.

[0108] [Battery configuration example] The following describes an example of the configuration of a battery using the electrode member illustrated in the above example of the manufacturing method, with reference to the drawings. Here, we will explain an example of a battery configuration that is particularly suitable for applications where the battery is repeatedly bent. Reveal.

[0109] FIG. 13(A) shows a schematic top view of the battery 50. Also, FIGS. 13(B1), (B2), and (C ) are cut lines C1-C2, C3-C4, and A1- A schematic cross-sectional view at A2 is shown.

[0110] The battery 50 has an exterior body 51 and an electrode member 10 housed inside the exterior body 51. The leads 12a and 12b of the electrode member 10 extend outside the outer casing 51. In addition to the electrode member 10, an electrolyte (not shown) is enclosed inside the exterior body 51. It is being done.

[0111] The exterior body 51 has a film-like shape and is folded in two so as to sandwich the electrode member 10. The exterior body 51 includes a folded portion 61, a pair of sealed portions 62, a sealed portion 63, and The pair of seal portions 62 are provided to sandwich the electrode member 10 and are also called side seals. The sealing portion 63 can be formed by sealing the lead 12a and the lead 12b in the overlapping portion. It can also be called a top seal.

[0112] The exterior body 51 has a corrugated shape in the area where it overlaps with the electrode member 10, with ridge lines 71 and valley lines 72 arranged alternately. In addition, the seal portion 62 and the seal portion 63 of the exterior body 51 preferably have a corrugated shape. It is preferable that the sealing portion 63 is flat and has no curve. There may be a step at the portion where it overlaps with the door 12b.

[0113] The configuration of the electrode member 10 can be based on the above.

[0114] FIG. 13(B1) is a cross section cut at the part overlapping with the ridge line 71, and FIG. 13(B2) is a cross section cut at the part overlapping with the ridge line 71. 13(B1) and 13(B2) are cross sections cut at the part overlapping with the valley line 72. 0 and corresponds to a cross section of the electrode member 10 in the width direction.

[0115] Here, the end of the electrode member 10 in the width direction, that is, the end of the current collector 11a or the current collector 11b The distance between the battery 50 and the seal portion 62 is defined as La. When this occurs, the current collectors 11a and 11b are displaced from each other in the longitudinal direction, as will be described later. At this time, if the distance La is too short, the outer casing 51 and the current collector 11a or the current collector 11 b may rub strongly against the exterior body 51, and the exterior body 51 may be damaged. If the metal film is exposed, it may be corroded by the electrolyte. Therefore, it is preferable to set the distance La as long as possible. If it is too large, the volume of the battery 50 will increase.

[0116] In addition, the thicker the electrode member 10 is, the more the distance between the end of the current collector 11a or the current collector 11b and the shielding portion becomes large. It is preferable to increase the distance La between the hole portion 62 and the base portion 63 .

[0117] More specifically, when the thickness of the electrode member 10 is t, the distance La is 0. 8 times or more and 3.0 times or less, preferably 0.9 times or more and 2.5 times or less, more preferably 1.0 times It is preferable that the distance La is in this range or more and 2.0 times or less. Furthermore, a battery with high reliability against bending can be realized.

[0118] Furthermore, when the distance between the pair of seal portions 62 is a distance Lb, the distance Lb is It is preferable that the width of the current collector 11a is sufficiently larger than the width of the current collector 11a (here, the width Wa of the current collector 11a). Therefore, when the battery 50 is repeatedly bent or deformed, the electrode member 10 and the outer casing 51 Even if the electrode member 10 comes into contact with the electrode member 10, a part of the electrode member 10 can be displaced in the width direction. This can effectively prevent the exterior body 51 from rubbing against each other.

[0119] For example, the distance Lb between the pair of seal portions 62 and the width Wa of the current collector 11a (or the width The difference between the width Wb of the electrode member 11 and the width Wb of the electrode member 11 is preferably 1.6 times or more and 6.0 times or less than the thickness t of the electrode member 10. The ratio should preferably be 1.8 times or more and 5.0 times or less, and more preferably 2.0 times or more and 4.0 times or less. It is preferable that:

[0120] In other words, it is preferable that the distance Lb, the width Wa, and the thickness t satisfy the following relationship: .

[0121]

number

[0122] Here, a is 0.8 or more and 3.0 or less, preferably 0.9 or more and 2.5 or less, and more preferably The value must be between 1.0 and 2.0.

[0123] FIG. 13(C) is a cross section including the lead 12a, showing the battery 50 and the electrode member 10 along the length. It corresponds to the cross section in the direction of the arrow.

[0124] FIG. 13(D) is a cross section in the case where an electrode member 10a is used instead of the electrode member 10. 1 shows a schematic diagram.

[0125] As shown in FIG. 13C, at the bent portion 61, the end portion in the longitudinal direction of the electrode member 10 That is, a space 73 is provided between the end of the current collector 11a or the current collector 11b and the outer casing 51. It is preferable to do so.

[0126] FIG. 14 shows a schematic cross-sectional view of the battery 50 when bent. This corresponds to the cross section taken along the line B1-B2 in the figure.

[0127] When the battery 50 is bent, the part of the exterior body 51 located on the outside of the bend stretches, and the part located on the inside The other part is deformed so as to shrink. More specifically, the part located outside the exterior body 51 is The wave amplitude is reduced and the wave period is increased. The part located at is deformed so that the wave amplitude is large and the wave period is small. In this way, the deformation of the exterior body 51 relieves the stress applied to the exterior body 51 due to bending. Therefore, the material that constitutes the exterior body 51 does not need to stretch. 1 can bend the battery 50 with little force without breaking.

[0128] As shown in FIG. 14, the current collector 11a and the current collector 11b are displaced relative to each other. At this time, the electrode member 10 deforms in such a manner that the plurality of current collectors 11a of the electrode member 10 The plurality of current collectors 11b are fixed at one end on the seal portion 63 side by a fixing member 17. The closer to the bent portion 61, the greater the amount of deviation. This relieves the stress on the electrode member 10, and the current collectors 11a and 11b themselves expand and contract. As a result, the battery 50 can be bent without damaging the electrode member 10. do.

[0129] In addition, in the case of a battery using a solid electrolyte or a highly viscous gel electrolyte, the electrode material When the entire electrode 10 is covered with the electrolyte, the current collector 11a and the current collector 11b are less likely to be displaced relative to each other. Therefore, the pair of current collectors 11a and 11b is previously bonded to each other. A plurality of laminates each having an electrolyte layer between the first and second electrodes are prepared, and the laminates are stacked. This makes it possible to achieve the above even when a solid electrolyte or a highly viscous gel electrolyte is used. The current collector 11a and the current collector 11b may be configured to be displaced relative to each other.

[0130] Furthermore, by providing a space 73 between the electrode member 10 and the exterior body 51, the electrode member The current collectors 11a and 11b located inside the neutral plane of the coil 10 are in contact with the outer casing 51. The two electrodes can be relatively displaced without any distortion.

[0131] The battery exemplified in this configuration example is free from damage to the exterior body and electrode members even when repeatedly bent and stretched. This battery is less likely to be damaged and its characteristics are less likely to deteriorate.

[0132] The above is a description of an example of the battery configuration.

[0133] [About each component] Hereinafter, the electrode member and each component of the battery according to one embodiment of the present invention will be described.

[0134] [Positive electrode] The positive electrode is composed of a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer can be formed on one or both surfaces of the positive electrode current collector.

[0135] The positive electrode current collector is made of metals such as stainless steel, gold, platinum, aluminum, and titanium, and It is possible to use a material that has high conductivity and does not dissolve at the potential of the positive electrode, such as an alloy of Elements that improve heat resistance, such as silicon, titanium, neodymium, scandium, and molybdenum It is also possible to use an aluminum alloy containing silicon. It may be formed of a metal element that forms a silicide by reacting with silicon. The group elements are zirconium, titanium, hafnium, vanadium, niobium, tantalum, Chromium, molybdenum, tungsten, cobalt, nickel, etc. The positive electrode current collector is a foil , plate (sheet), mesh, punched metal, expanded metal, etc. The thickness of the positive electrode current collector is preferably 5 μm or more and 30 μm or less. In addition, an undercoat layer made of graphite or the like may be provided on the surface of the positive electrode current collector. good.

[0136] The positive electrode active material layer contains not only the positive electrode active material but also a binder (binder) to improve the adhesion of the positive electrode active material. d) The positive electrode active material layer may contain a conductive additive or the like to increase the conductivity of the positive electrode active material layer.

[0137] The positive electrode active material used in the positive electrode active material layer has an olivine type crystal structure, a layered rock salt type crystal structure, or Examples of positive electrode active materials include composite oxides with a crystalline structure or a spinel structure. For example, LiFeO2, LiCoO2, LiNiO2, LiMn2O4, V2O5, Cr2 Compounds such as O5 and MnO2 are used.

[0138] In particular, LiCoO2 has a large capacity and is more stable in the atmosphere than LiNiO2. It is preferable because it has the advantages of being thermally stable compared to LiNiO2.

[0139] In addition, lithium-containing manganese-containing spinel-type crystal structures such as LiMn2O4 are also available. The material contains a small amount of lithium nickel oxide (LiNiO2 or LiNi 1-x M x O2(0 <x< 1) By mixing (M=Co, Al, etc.), the characteristics of the secondary battery using this can be improved. This is preferable.

[0140] Alternatively, 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, LiFe a Mn b PO4, LiNi a Co b PO4, LiNi a Mn b PO4(a+b is less than 1, 0 <a<1、0<b<1)、Li Fe c Nid 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., can be used as materials for lithium compounds.

[0141] In particular, LiFePO4 satisfies well the requirements for a cathode active material, such as safety, stability, high capacity density, and the presence of lithium ions that can be extracted during initial oxidation (charging), so it is preferable. <00009‘62> Or, a composite material such as the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II), Co[[ID=‘43]] (II), Ni(II), 0 ≤ j ≤ 2) can be used. As a representative example of the general formula Li (2-j) MSiO4, there are 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) Ni k Co It should be noted that there may be some inaccuracies in the original text, such as the "‘43]] " and "‘44]](II), Ni(II), 0 ≤ j ≤ 2)" and "‘45]] " and "‘49]] (2-j) " and "‘51]] ( " and "‘52]] " and "‘53]] 2-j) " and "‘74]] ? " which seem to have some incorrect characters. The translation is done based on the best understanding of the original text.l SiO4, Li (2-j) Ni k Mn l SiO4 (where k + l is less than or equal to 1, 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 (where m + n + q is less than or equal to 1, 0 < m < 1, 0 < n < 1, 0 < q < 1 [[ID=......]] (the ellipsis indicates that the original text might be incomplete or there are additional parts not shown clearly in the provided sample. The translation is done based on what's available.) )、Li (2-j) Fe r Ni s Co t Mn u SiO4 (where r + s + t + u is less than or equal to 1, 0 < r < 1, 0 < s < 1, 0 < t < 1, 0 < u < 1), etc. Lithium compounds can be used as materials for this purpose.

[0143] Also, as the positive electrode active material, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, Nb, X = S, P, Mo, W, As, Si) represented by the general formula can be used. As the NASICON type compound, there are Fe2(MnO4)3, Fe2(SO4)3, Li3Fe2(PO4)3, etc. Also, as the positive electrode active material, L i2MPO4F, Li2MP2O7, Li5MO4 (M = Fe, Mn) represented by the general formula compounds, perovskite type fluorides such as NaFeF3, FeF3, metal chalcogenides (sulfides, selenides, tellurides) such as TiS2, MoS2 etc., oxides having an inverse spinel type crystal structure such as LiMVO4, vanadium oxide systems (V2O5, V6O ......) 13, LiV 3O8, etc.), manganese oxide, organic sulfur compounds, and other materials can be used.

[0144] In addition, the carrier ions may be alkali metal ions other than lithium ions or alkaline earth ions. In the case of metal ions, alkali metals (e.g., sodium) are used as the positive electrode active material instead of lithium. thorium, potassium, etc.), alkaline earth metals (e.g., calcium, strontium, barium, etc.), For example, NaFeO2 or Na 2 / 3 [Fe 1 / 2 Mn 1 / 2 ]O2 as the positive electrode active material. It can be used as such.

[0145] Furthermore, a combination of two or more of the above materials may be used as the positive electrode active material. For example, A solid solution of a combination of the above materials can be used as the positive electrode active material. iCo 1 / 3 Mn 1 / 3 Ni 1 / 3 A solid solution of O2 and Li2MnO3 is used as the positive electrode active material. You can be there.

[0146] A conductive material such as a carbon layer may be provided on the surface of the positive electrode active material layer. By providing a conductive material, the conductivity of the electrode can be improved. The carbon layer is coated on the cathode active material by mixing carbohydrates such as glucose during the firing process. It can be formed.

[0147] The average particle size of the primary particles in the granular positive electrode active material layer is 50 nm or more and 100 μm or less. It's good to have one.

[0148] Conductive additives include acetylene black (AB), graphite particles, and carbon black. Nanotubes, graphene, fullerene, etc. can be used.

[0149] The conductive additive can form an electron conductive network in the positive electrode. This allows the electrical conduction path between the positive electrode active material layers to be maintained. By adding a conductive additive, it is possible to realize a positive electrode active material layer with high electronic conductivity. can.

[0150] In addition to the typical polyvinylidene fluoride (PVDF), polyimide is also used as a binder. , polytetrafluoroethylene, polyvinyl chloride, ethylene propylene diene poly styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, poly Polyvinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, etc. It is possible.

[0151] The preferred range of the binder content relative to the total amount of the positive electrode active material layer depends on the particle size of the active material. The content can be appropriately set, preferably in the range of 1 wt% to 10 wt%. For example, it can be 2 wt% or more and 8 wt% or less, or 3 wt% or more and 5 wt% or less. The content of the conductive additive relative to the total amount of the positive electrode active material layer is 1 wt% or more and 10 wt% or less. The content is preferably 1 wt % or less and more preferably 1 wt % or more and 5 wt % or less.

[0152] When forming a positive electrode active material layer using a coating method, the positive electrode active material, binder, and conductive additive are mixed. The resulting mixture is mixed to prepare a positive electrode paste (slurry), which is then applied onto a positive electrode current collector and dried.

[0153] [Negative electrode] The negative electrode is composed of a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector. The negative electrode active material layer can be formed on one or both surfaces of the negative electrode current collector.

[0154] The negative electrode current collector is made of metals such as stainless steel, gold, platinum, iron, copper, titanium, and alloys of these metals. It is possible to use materials that have high conductivity and do not alloy with carrier ions such as lithium. In addition, the heat resistance of silicon, titanium, neodymium, scandium, molybdenum, etc. can be improved. The negative electrode current collector may be an aluminum alloy containing an element that enhances the resistance to oxidation. , plate (sheet), mesh, punched metal, expanded metal, etc. The thickness of the negative electrode current collector is preferably 5 μm or more and 30 μm or less. In addition, an undercoat layer made of graphite or the like may be provided on the surface of the negative electrode current collector. good.

[0155] The negative electrode active material layer contains not only the negative electrode active material but also a binder (binder) to improve the adhesion of the negative electrode active material. d) The negative electrode active material layer may contain a conductive additive or the like to increase the conductivity of the negative electrode active material layer.

[0156] The negative electrode active material is a material that can dissolve and deposit lithium or insert and extract lithium ions. The material for the negative electrode active material layer is not particularly limited as long as it is a material. In addition to lithium, examples include carbon-based materials and alloy-based materials that are commonly used in the field of energy storage.

[0157] Lithium metal has a low redox potential (-3.045 V vs. the standard hydrogen electrode) and is lightweight. and high specific capacity per volume (3860mAh / g and 2062mAh / cm, respectively). 3 ) and is therefore preferable.

[0158] Carbon materials include graphite, easily graphitizable carbon (soft carbon), and non-graphitizable carbon (hard carbon). carbon nanotubes, graphene, carbon black, etc. .

[0159] As graphite, mesocarbon microbeads (MCMB), coke-based artificial graphite, Examples of the graphite include artificial graphite such as titanium-based artificial graphite, and natural graphite such as spheroidized natural graphite.

[0160] When lithium ions are inserted between the layers of graphite (the formation of lithium-graphite intercalation compounds), Sometimes), it shows a potential as low as that of lithium metal (0.1 to 0.3 V vs. Li / L i + This allows lithium-ion batteries to exhibit high operating voltages. Graphite has a relatively high capacity per unit volume, small volume expansion, is inexpensive, and is a lithium It is preferable because it has advantages such as higher safety compared to metals.

[0161] As a negative electrode active material, it can carry out charge-discharge reactions by alloying and dealloying reactions with lithium. Possible alloy materials or oxides can also be used. In this case, examples of alloy materials include Mg, Ca, Al, Si, Ge, Sn, and Pb. , Sb, Bi, Ag, Au, Zn, Cd, Hg, In, etc. These elements have a large capacity compared to carbon, and silicon in particular has a theoretical capacity The capacity is dramatically high at 4200mAh / g. Therefore, using silicon as the negative electrode active material As alloy materials using such elements, for example, Mg2Si, Mg2 Ge, Mg2Sn, SnS2, V2Sn3, FeSn2, CoSn2, Ni3Sn2, C u6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La 3Co2Sn7, CoSb3, InSb, SbSn, etc.

[0162] In addition, the negative electrode active material is SiO, SnO, SnO2, titanium oxide (TiO2), lithium Sodium titanium oxide (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), Niobium oxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2) The oxides may be used.

[0163] In addition, the negative electrode active material is a composite nitride of lithium and transition metals, which has a Li3N structure. つLi 3-x M x N (M=Co, Ni, Cu) can be used. For example, Li 2. 6Co 0.4 N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm 3 )of This is preferable.

[0164] When a composite nitride of lithium and transition metals is used, lithium ions are included in the negative electrode active material, As a positive electrode active material, materials that do not contain lithium ions, such as V2O5 and Cr3O8, are used. In addition, when a material containing lithium ions is used as the positive electrode active material, However, by first removing the lithium ions contained in the positive electrode active material, As the substrate, a complex nitride of lithium and a transition metal can be used.

[0165] In addition, a material that undergoes a conversion reaction can also be used as the negative electrode active material. For example, lithium oxides such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO) A transition metal oxide that does not undergo an alloying reaction with the metal may be used as the negative electrode active material. Further materials that can react include Fe2O3, CuO, Cu2O, RuO2, Cr2 Oxides such as O3, CoS 0.89 , sulfides such as NiS and CuS, Zn3N2, Cu3N, Nitrides such as Ge3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF This also occurs with fluorides such as 3. Note that the potential of the above fluorides is high, so they are not used as positive electrode active materials. It's fine.

[0166] When forming the negative electrode active material layer using the coating method, the negative electrode active material and the binder are mixed and applied to the negative electrode. The paste (slurry) is prepared, applied to the negative electrode current collector, and then dried. A conductive additive may be added to the paste.

[0167] Graphene may be formed on the surface of the negative electrode active material layer. When the material is reconstituted, the volume change due to the absorption and release of carrier ions during the charge / discharge cycle is As a result, the adhesion between the negative electrode current collector and the negative electrode active material layer decreases, and the battery characteristics deteriorate during charging and discharging. Therefore, graphene is formed on the surface of the negative electrode active material layer containing silicon. Even if the volume of silicon changes during the charge-discharge cycle, the negative electrode current collector and the negative electrode active material This is preferable because it can prevent a decrease in adhesion with the material layer and reduce deterioration of the battery characteristics. stomach.

[0168] In addition, a coating of an oxide or the like may be formed on the surface of the negative electrode active material layer. The film formed by the decomposition of the liquid can release the charge consumed during its formation. In order to prevent this, a film of oxide or the like is formed on the negative electrode active material layer in advance. By providing it on the surface, the occurrence of irreversible capacity can be suppressed or prevented.

[0169] The coating that coats the negative electrode active material layer may contain niobium, titanium, vanadium, tantalum, or the like. , tungsten, zirconium, molybdenum, hafnium, chromium, aluminum or is an oxide film of any one of silicon, or an oxide film containing any one of these elements and lithium Such a coating can be used to prevent the decomposition products of conventional electrolytes from forming on the negative electrode surface. This is a sufficiently dense film compared to the coating formed on the surface of the substrate.

[0170] For example, niobium oxide (Nb2O5) has an electrical conductivity of 10 -9 Low S / cm and high Therefore, the niobium oxide film prevents the electrochemical decomposition reaction between the negative electrode active material and the electrolyte. On the other hand, the lithium diffusion coefficient of niobium oxide is 10 -9 cm 2 / sec, and high It has high lithium ion conductivity, which allows lithium ions to pass through. Silicon oxide or aluminum oxide may also be used.

[0171] The film that covers the negative electrode active material layer can be formed by, for example, a sol-gel method. The sol-gel method is a process in which a solution of metal alkoxides or metal salts is subjected to hydrolysis and polycondensation. This method involves forming a gel that has lost its fluidity through a reaction, and then baking this gel to form a thin film. The lubrication method is a method for forming thin films from a liquid phase, so the raw materials must be mixed homogeneously at the molecular level. For this reason, the negative electrode active material such as graphite is added to the raw material of the metal oxide film at the solvent stage. By adding the active material, it is possible to easily disperse the active material in the gel. A coating can be formed on the surface of the material layer. By using this coating, the capacity of the battery can be reduced. It can prevent the bottom from falling out.

[0172] [Separator] Materials for forming the separator include cellulose, polypropylene (PP), Polyethylene (PE), polybutene, nylon, polyester, polysulfone, polyacrylic Nitrile, polyvinylidene fluoride, tetrafluoroethylene, polyphenylene sulfur Porous insulators such as glass fiber or nonwoven fabrics such as glass fiber can also be used. A membrane made of a composite of fiber and polymer fiber may also be used.

[0173] [Electrolyte] The electrolytic solution is an electrolyte in which carrier ions can move and which are carrier ions. The electrolyte is made of a material containing lithium ions. Typical examples of the electrolyte are LiPF6, LiC lO4, LiAsF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N, L These include lithium salts such as Li(C2F5SO2)2N and Li(SO2F)2N. The materials may be used singly or in any combination and ratio of two or more. .

[0174] In particular, when high-temperature processing is performed during molding of rubber, etc., the electrolyte must have high heat resistance. For example, it is preferable to use an imide salt having a high thermal decomposition temperature.

[0175] As the solvent for the electrolyte, a material in which carrier ions can move is used. The solvent is preferably an aprotic organic solvent. Typical examples of the aprotic organic solvent include: , ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-benzyl These include tyrolactone, acetonitrile, dimethoxyethane, and tetrahydrofuran. One or more of these can be used. In addition, a polymer that can be gelled as a solvent for the electrolyte can be used. By using a polymer material or adding a polymer material to the electrolyte for gelation, leakage resistance, etc. This improves safety against fires. It also makes it possible to make the storage battery thinner and lighter. Representative examples of polymeric materials include silicone gel, acrylic gel, acrylonitrile gel, Polyethylene oxide gel, polypropylene oxide gel, fluorine polymer In addition, flame-retardant and non-volatile ionic liquids (at room temperature) are used as solvents for electrolytes. By using one or more molten salts, the internal temperature of the battery can be reduced by an internal short circuit or overcharging. Even if the temperature rises, it can prevent the battery from exploding or catching fire. Ionic liquids are salts in a mobile state, and have high ion mobility (conductivity). The ionic liquid includes ethylmethylimidazolium (EMI) cationic anion. Ionic liquids containing N-methyl-N-propylpiperidinium (PP 13 )mosquito Examples include ionic liquids containing thiones.

[0176] In particular, when high-temperature processing is performed, the solvent for the electrolyte should be a material with a high boiling point. For example, it is preferable to use propylene carbonate (PC).

[0177] [Exterior body] There are various types of secondary battery structures. In this embodiment, a film is used as the exterior body. The film used to form the exterior is a metal film (aluminum, stainless steel). stainless steel, nickel steel, etc.), plastic film made of organic materials, organic materials (organic resin Hybrid material films containing inorganic materials (such as ceramics) and carbon A single layer film selected from inorganic films (carbon film, graphite film, etc.) The metal film is embossed. Embossing makes it easier to form recesses or protrusions on the exterior surface that is exposed to the air. The increased surface area provides excellent heat dissipation.

[0178] In addition, if the shape of the secondary battery is changed by applying external force, the external Bending stress may be applied from the outside, causing deformation or partial destruction of the exterior body. By forming a recess or protrusion on the exterior, distortion caused by stress applied to the exterior can be reduced. Therefore, the reliability of the secondary battery can be improved. The strain is a measure of the displacement of a material point within an object relative to the reference (initial) length of the object. By forming a recess or protrusion on the exterior body, strain caused by applying force from outside the battery can be reduced. Therefore, the influence of the battery on the battery pack can be suppressed within an acceptable range. It is possible.

[0179] This concludes the explanation of each component.

[0180] This embodiment may be combined, at least in part, with other embodiments described in this specification. It can be implemented in combination.

[0181] (Embodiment 2) In this embodiment, a battery obtained by using the first embodiment, particularly a battery incorporating a secondary battery, An example of a child device is shown below.

[0182] The secondary battery obtained using the first embodiment has a thin, flexible film exterior. This allows it to be deformed into a flexible shape.

[0183] Do not allow parts of electronic devices, such as watches, to come into contact with parts of the user's body (wrist, arm, etc.). In other words, by having the user wear the electronic device, the user can feel that the electronic device is lighter than its actual weight. Electronic devices with an exterior shape that has a curved surface that fits a part of the user's body. By using a flexible secondary battery, the secondary battery can be fixed in a shape suitable for electronic devices. It can be installed.

[0184] In addition, if the user moves the part of the body where the electronic device is worn, the electronic device may move along with the part of the body. Even if the electronic device has a curved surface, users will feel uncomfortable and perceive the device as a nuisance. Therefore, flexible secondary batteries are used in parts of electronic devices that may be deformed. By providing a pond, at least a part of the electronic device can be deformed according to the movement of the body. This makes it possible to provide an electronic device that users will not find strange. .

[0185] Alternatively, the external shape of the electronic device is not limited to curved or complex shapes, but may be simple. For example, in an electronic device with a simple external appearance, The number and size of components that can be housed in a device are determined by the volume of the space formed by the electronic device's housing. By placing a flexible secondary battery in the gap between components other than the secondary battery, This allows for effective use of the space formed by the housing of the child device, and also allows for miniaturization.

[0186] Wearable devices include wearable cameras, wearable microphones, and Wearable input devices such as wearable sensors, wearable displays, and wearable Wearable output devices such as earphones and earphones, as well as wearable devices that combine these functions, are also being considered. It includes input / output terminals. Also, wearable devices are devices that control each device, calculate data, or The processing device includes a wearable computer having a CPU. A wearable device is a device that stores, transmits, or receives data. Generally speaking, this also includes mobile information terminals and memory.

[0187] As an example of an electronic device that uses a secondary battery with a flexible shape, there is a headset. Display devices such as front displays and goggle displays, televisions (television receivers), (also called a mobile phone), personal computers such as desktop and notebook computers, monitors, digital cameras, digital video cameras, digital photo frames, Child notebooks, e-book terminals, electronic translators, toys, voice input devices such as microphones, electric shells electric toothbrushes, microwave ovens and other high-frequency heating devices, electric rice cookers, electric washing machines, electric vacuum cleaners Air conditioners such as vacuum cleaners, water heaters, electric fans, hair dryers, humidifiers, dehumidifiers, and air conditioners Equipment, dishwasher, dish dryer, clothes dryer, futon dryer, electric refrigerator, electric freezer, Air-conditioning refrigerators, DNA storage freezers, flashlights, power tools, smoke detectors, gas alarms and fire prevention equipment Alarm devices such as burglar alarms, industrial robots, hearing aids, cardiac pacemakers, X-ray equipment, Radiation measuring devices, health and medical equipment such as electric massagers and dialysis machines, mobile phones (mobile phones Telephones, also known as mobile phone devices, portable game consoles, personal digital assistants, lighting devices, headphones , stereos, remote controls, clocks such as table clocks and wall clocks, cordless telephones Portable or stationary devices such as mobile phones, transceivers, pedometers, calculators, digital audio players, etc. Examples include audio playback devices and large game machines such as pachinko machines.

[0188] In addition, the flexible secondary battery can be attached to the inner or outer wall of a house or building, or to an automobile. It can also be incorporated into curved surfaces of the interior or exterior of a vehicle.

[0189] FIG. 15A shows an example of a mobile phone. The mobile phone 7400 includes a housing 740 1, in addition to a display unit 7402, operation buttons 7403, an external connection port 7404, The mobile phone 7400 is equipped with a speaker 7405, a microphone 7406, and the like. It has a secondary battery 7407.

[0190] FIG. 15B shows the mobile phone 7400 in a bent state. When the entire 00 is deformed by an external force and curved, the secondary battery installed inside The secondary battery 7407 is also bent. At this time, the state of the bent secondary battery 7407 is as shown in FIG. C). The secondary battery 7407 is a laminated structure battery (a laminated structure battery, film exterior The secondary battery 7407 is fixed in a bent state. The secondary battery 7407 has a lead electrode 7408 electrically connected to a current collector 7409. For example, the exterior film of the secondary battery 7407 is embossed, The battery 7407 has a highly reliable structure even when bent. The 7400 has a slot for inserting a SIM card and a USB device such as a USB memory stick. A connector portion for connecting the sensor may be provided.

[0191] Figure 15(D) shows an example of a bendable mobile phone. If it is bent into a certain shape, it can be made into a bangle-type mobile phone as shown in Figure 15(E). The phone 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a secondary battery 71 15(F) shows the secondary battery 7104 in a bent state. When the device 104 is bent and worn on the user's arm, the housing is deformed and the secondary battery 7104 is Part or all of the curvature changes. Specifically, the curvature radius is between 10 mm and 150 mm. Within this range, a part or the whole of the main surface of the housing or the secondary battery 7104 changes. The secondary battery 7104 has a lead electrode 7105 electrically connected to a current collector 7106. For example, a press forming method for forming a plurality of irregularities on the surface of the film of the exterior body of the secondary battery 7104 is used. The secondary battery 7104 has been bent many times with its curvature changed, and high reliability is achieved. Furthermore, the mobile phone 7100 is designed to maintain reliability. It is equipped with a slot for connecting a USB memory stick and a connector for connecting a USB device. Also, when the central part of the mobile phone shown in FIG. 15(D) is folded, the mobile phone shown in FIG. ) and you can also fold the center of the mobile phone further to make it look like this. As shown in Figure 15(H), the edges of the mobile phone overlap to make it smaller and fit in the user's pocket. In this way, the mobile phone shown in FIG. 15(D) can be made to fit into a pocket or the like. It is an electronic device that can change its shape, and in order to achieve this, it needs at least a housing 7 It is desirable that the display portion 7102 and the secondary battery 7104 have flexibility.

[0192] Furthermore, the power storage device described in the first embodiment may be installed in a wearable device as shown in FIG. It can be installed.

[0193] For example, it can be mounted on a glasses-type device 400 as shown in FIG. The mirror-type device 400 has a frame 400a and a display unit 400b. By installing a power storage device in the temple of the REM 400a, the weight balance is good and it can be used continuously. The eyeglass-type device 400 can be used for a long time.

[0194] It can also be installed in a headset type device 401. The microphone 401 includes at least a microphone part 401a, a flexible pipe 401b, and an earphone. The flexible pipe 401b and the earphone section 401c store electricity. A device can be provided.

[0195] It can also be mounted on a device 402 that can be attached directly to the body. A power storage device 402b can be provided in a thin housing 402a of the display device 02.

[0196] It can also be mounted on a device 403 that can be attached to clothing. A power storage device 403b can be provided in the thin housing 403a.

[0197] It can also be installed in a wristwatch type device 405. The wristwatch type device 405 is The display unit 405a and the belt unit 405b are A power storage device may be provided.

[0198] The display unit 405a displays not only the time but also various information such as incoming emails and phone calls. It is possible.

[0199] The wristwatch type device 405 is a wearable device that is worn directly on the wrist. Therefore, sensors for measuring the user's pulse, blood pressure, etc. may be installed. It can also accumulate health-related data and be used to help maintain good health.

[0200] It can also be mounted on a belt-type device 406. The belt-type device 406 includes: It has a belt part 406a and a wireless power receiving part 406b, and inside the belt part 406a A power storage device can be mounted on the vehicle.

[0201] FIG. 16B is a projection view illustrating an example of the appearance of the information processing device 200. The information processing device 200 described in the embodiment includes a calculation device 210, an input / output device 220, and a display unit 2 30 and a power storage device 250.

[0202] The information processing device 200 has a communication unit, and the communication unit supplies information to a network and It also has a function to acquire information from the network. The image information may be generated based on the received information. , can receive and display teaching materials distributed in classrooms at schools or universities, etc., and use them as textbooks. Or, materials distributed in a company's conference room can be received and displayed.

[0203] This embodiment may be combined, at least in part, with other embodiments described in this specification. It can be implemented in combination. [Example]

[0204] In this example, a battery according to one embodiment of the present invention was manufactured. It was produced based on the method illustrated in Example Method 1.

[0205] The positive electrode current collector is made of aluminum foil with a positive electrode active material layer on one side and a negative electrode active material layer on the other side. Six negative electrode current collectors made of copper foil were prepared. LiCoO2 was used as the positive electrode active material. Graphite was used as the negative electrode active material.

[0206] The positive electrode current collectors are stacked with the surfaces opposite to the coated surfaces facing each other, and then attached to a pair of positive electrode current collectors. The container was covered with a bag-shaped separator.

[0207] Next, as shown in FIG. 17(A), a positive electrode current collector covered with a separator and a negative electrode current collector Then, as shown in FIG. 17(B), the positive electrode current collector and Leads were joined to the tabs of the positive and negative electrode current collectors by ultrasonic welding. is an enlarged view of FIG. 17(B).

[0208] Next, as shown in FIG. 18(A), a polyimide insulating material is applied to cover the pair of joints. Figure 18(B) is a photograph of the device turned inside out, and Figure 18(C) is a photograph of the device turned inside out. This is an enlarged view of (A).

[0209] Next, the tab portions of the positive electrode current collector and the negative electrode current collector were folded back. In order to fix the tab portion, the positive electrode current collector, and the negative electrode current collector, a polyimide tape is used as a fixing member. Figure 19(B) is a photograph of the joint side, and Figure 19(A) is a photograph of the reverse side. 19(C) is an enlarged view of FIG. 19(B).

[0210] In this way, the electrode member was completed.

[0211] Next, the electrode member is sandwiched between exterior bodies to form side seals and top seals. So, I made a battery.

[0212] The exterior is made of polypropylene, aluminum foil, and nylon laminated in that order, with a thickness of approximately A 70 μm aluminum laminate film was used. The wave pitch was 2 mm, and the distance between the convex and concave portions was 1 / 4. The film was processed so that the height difference was 0.5 mm.

[0213] The joining to form the seal part of the film is done using a mold (heat bar) with a flat surface. The side seal was made using a 1mm wide heat bar, and the top seal was made using a lead A 2 mm wide heat bar with a groove formed in the position facing the part was used.

[0214] Figures 20(A) and (B) show the external appearance of the battery. The side seals are extremely flat, and the area near the edge of the film is The wave period is longer and the amplitude is smaller at one end of the film than at the center. It can be seen that the part is deformed.

[0215] The above is the description of the first embodiment.

[0216] This embodiment may be any of the other embodiments or embodiments described, at least in part, herein. can be implemented in combination as appropriate. [Example]

[0217] In the following, a battery according to one embodiment of the present invention and a comparative battery were fabricated, and their internal structures were described. The results of photographing the structure and evaluating the electrical properties before and after repeated bending tests will be explained. .

[0218] [Sample preparation] First, the following three types of samples (Comparative Sample 1, Comparative Sample 2, and Sample 1) were prepared.

[0219] The positive electrode current collector is made of 9 mm wide aluminum foil, and the negative electrode current collector is made of 10 mm wide copper foil. Here, a positive electrode current collector and a negative electrode current collector each having an active material layer on one side were used. Six sheets of each were stacked.

[0220] Sample 1 was produced by the same method as in Example 1. Sample 1 also contained a A pre-embossed aluminum laminate film with a width of 16 mm was used.

[0221] For comparative samples 1 and 2, the fixed portion between the lead and the current collector was only the joint. Comparative Sample 1 and Comparative Sample 2 were also prepared by embossing in advance, similar to Sample 1. The exterior of the comparative sample 1 was made of an aluminum laminate film with a width of 100 mm. The exterior of the comparative sample 2 was made of a 15 mm aluminum laminate film. A 16 mm wide aluminum laminate film was used.

[0222] [Observation of internal structure] The prepared comparative sample 2 and sample 1 were subjected to X-ray computed tomography (X-ray computed tomography). The inside of the battery was observed using a tomography (CT).

[0223] 21(A), (B), and (C) show radiographs taken of Comparative Sample 2. FIG. 21(A) is a photograph taken in a lateral direction, FIG. 21(B) is a photograph taken in a plan view, and FIG. 21 (C) is an enlarged photograph of the vicinity of the tab portion in FIG. 21(A).

[0224] Here, X-rays penetrate lighter elements more easily, so the exterior and the positive electrode made of aluminum foil are used. The electrode current collector and the like are transparent images.

[0225] As shown in FIG. 21(C), the joint between the lead and the tab is in the region having the active material layer of the current collector. The area is provided at a position separated from the laminated portion.

[0226] Figures 22(A), (B), and (C) show X-ray photographs taken of Sample 1. As shown in 2(C), the tab part of the current collector is folded back. It was confirmed that the joint with the lead overlapped the part where the current collector was laminated.

[0227] The only difference between Comparative Sample 1 and Comparative Sample 2 is the width of the exterior body, so the figure is omitted. Abbreviated.

[0228] [Bending and stretching test] Subsequently, the bending and stretching test was repeatedly carried out on Comparative Sample 1, Comparative Sample 2, and Sample 1. The bending and stretching test was carried out by repeatedly bending the specimen at a radius of curvature of 25 mm and then leaving it flat. It was.

[0229] After 6,000 bending and stretching tests, the exterior of the comparative sample 1 was damaged and the electrolyte leaked. The damaged part of the exterior body of Comparative Sample 1 was where the exterior body and the edge of the negative electrode current collector came into contact. It was located in the area where

[0230] On the other hand, the comparative sample 2 and sample 1 did not sustain any damage to the exterior body even after 10,000 bending and stretching tests. No leakage of electrolyte was observed.

[0231] [Observation of internal structure 1] Figure 23(A), (B), and (C) show X-ray CT images of the cross section of each sample before the bending and stretching test. Fig. 23(A) shows Comparative Sample 1, Fig. 23(B) shows Comparative Sample 2, and Fig. 23(C) shows Test Sample. This is a cross section of material 1 along the valley line of the exterior body.

[0232] Here, the value of a in formula (2) was estimated. Here, L is the distance between a pair of side seals. distance, W is the width of the negative electrode current collector, t is the thickness of the electrode material (the distance between the two outer negative electrode current collectors) distance).

[0233]

number

[0234] The estimated value of a for Comparative Sample 1 was 0.66. The estimated a value for sample 1 was 1.04, and the estimated a value for sample 2 was 1.03. It was.

[0235] From the above results, in the comparative sample 1, the gap between the end of the negative electrode current collector and the side seal was The results of the bending and stretching test showed that the width of the In sample 1, the edge of the negative electrode current collector came into contact with the exterior body, causing the exterior body to be damaged. It turns out that a space of 100 degrees is insufficient.

[0236] On the other hand, in the comparative sample 2 and the sample 1, the gap between the end of the negative electrode current collector and the side seal was The width of the wire is 0.8 times or more the thickness. Since no damage was observed, it is clear that there is sufficient space between them. Confirmed.

[0237] [Charge / discharge characteristics] The charge-discharge characteristics of each sample were measured before and after the bending and stretching test.

[0238] Figures 24(A) and (B) show the characteristics of Comparative Sample 1. Figure 24(A) shows the results of the bending and stretching test. Figure 24(B) shows the characteristics before and after 3000 bending and stretching tests. In the graph, the vertical axis represents voltage and the horizontal axis represents capacity per unit weight of the positive electrode active material. As shown in Figures 24(A) and (B), a decrease in capacity was confirmed by the bending and stretching test. .

[0239] Figures 25(A) and (B) show the characteristics of comparative sample 2. Figure 25(B) shows the characteristics of comparative sample 2 after 10,000 bending cycles. These are the characteristics after the bending test. As shown above, no damage to the exterior body was observed in Comparative Sample 2. However, a decrease in capacity was confirmed by bending and stretching tests.

[0240] 26(A) and (B) show the characteristics of Sample 1. Fig. 26(B) shows the characteristics after 10,000 bending cycles. The characteristics after the bending and stretching test. For sample 1, there was almost no decrease in capacity before and after the bending and stretching test. The discharge capacity before the bending and stretching test was 134.0 [mAh / g]. On the other hand, the discharge capacity after the test was 133.3 [mAh / g].

[0241] [Observation of internal structure 2] Next, the comparative sample 2 and the sample 1 were subjected to the bending and stretching test 10,000 times. X-ray photographs were taken to observe the internal structure.

[0242] FIG. 27(A) shows a lateral X-ray photograph of the vicinity of the tab portion of Comparative Sample 2. In the figure, the broken line As shown in the area enclosed by a circle, it was confirmed that part of the negative electrode current collector was broken. Therefore, it is believed that the decrease in capacity is caused by the breakage of the tab portion.

[0243] Figure 27(B) shows a lateral X-ray photograph of the vicinity of the tab portion of Sample 1. It was confirmed that there was almost no change when compared with the radiographic photograph before the procedure (Figure 22(C)). Done.

[0244] From the above results, it can be seen that the battery according to one embodiment of the present invention shows almost no decrease in capacity even after repeated bending and stretching. Almost no leakage was observed, confirming that this is an extremely reliable battery.

[0245] The above is the description of the second embodiment.

[0246] This embodiment may be any of the other embodiments or embodiments described, at least in part, herein. can be implemented in appropriate combination. [Explanation of symbols]

[0247] 10 Electrode material 10a Electrode member 11a Current collector 11b Current collector 12a Lead 12b lead 13a Active material layer 13b Active material layer 14 Separator 14a Separator 15a Joint 15b Joint 16 Insulating material 16a Insulating member 16b Insulating member 17 Fixing member 18 Insulating material 18a Insulating material 18b Insulating member 18c Insulating material 21a Tab part 21b Tab part 22a Electrode part 22b Electrode part 50 batteries 51 Exterior body 61 Bending section 62 Seal part 63 Seal part 71 Ridgeline 72 Valley Line 73 Space 200 Information processing device 210 Arithmetic equipment 220 Input / Output Devices 230 Display section 250 Electricity storage device 290 Communications Department 400 Eyeglasses-type device 400a frame 400b Display section 401 Headset-type device 401a Microphone section 401b Flexible Pipe 401c Earphone section 402 Device 402a housing 402b Energy storage device 403 Device 403a housing 403b Energy storage device 405 Wristwatch-type device 405a Display section 405b Belt section 406 Belt-type device 406a Belt section 406b Wireless power receiving unit 7100 Mobile Phone 7101 Housing 7102 Display section 7103 Operation button 7104 Secondary battery 7105 Lead electrode 7106 Current collector 7400 mobile phone 7401 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Secondary battery 7408 Lead electrode 7409 Current collector

Claims

1. a positive electrode current collector including a first tab portion, a first lead, a first joint portion at which the first tab portion and the first lead are joined, a negative electrode current collector including a second tab portion, a second lead, a second joint portion at which the second tab portion and the second lead are joined, and an insulating member; A secondary battery, wherein the insulating member covers a portion of the first tab portion, a portion of the first lead, the first joint portion, a portion of the second tab portion, a portion of the second lead, and the second joint portion.

2. a positive electrode current collector including a first tab portion, a first lead, a first joint portion at which the first tab portion and the first lead are joined, a negative electrode current collector including a second tab portion, a second lead, a second joint portion at which the second tab portion and the second lead are joined, a first insulating member, and a second insulating member; the first insulating member covers a portion of the first tab portion, a portion of the first lead, and the first joint portion; A secondary battery, wherein the second insulating member covers a portion of the second tab portion, a portion of the second lead, and the second joint portion.

3. In claim 1 or 2, The insulating member, the first insulating member, or the second insulating member comprises polyimide.

4. In any one of claims 1 to 3, The insulating member, the first insulating member, or the second insulating member is bag-shaped.

Images