JP2007317668A - Display function mounted electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display function mounted electronic device provided with an electromagnetic wave shielding member which is excellent in an electromagnetic wave shielding effect. <P>SOLUTION: The display function mounted electronic device is provided with a central treatment unit, a display unit part 12 and an electromagnetic wave shielding member 17 arranged on a rear surface of the display unit part 12, and the electromagnetic wave shielding member 17, while satisfying the below-mentioned formula (1), is provided with a protecting circuit 15 and a battery pack of slim nonaqueous electrolyte secondary batteries 2 which are connected with the protecting circuit 15 and hold the protecting circuit 15 in-between. The slim nonaqueous electrolyte secondary battery 2 is provided with an electrode group which is wound in a flat shape with a separator between a cathode and an anode, a nonaqueous electrolyte containing γ-butyrolactone and a container to accommodate the electrode group and the nonaqueous electrolyte.100≤X/Y≤50000 (1) In the formula (1), X is for an operating frequency (MHz) of a calculating part of the central treatment unit and Y is for a capacity (Ah) of the slim nonaqueous electrolyte secondary battery. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave shielding material and a display function-equipped electronic device including the electromagnetic wave shielding material.

Currently, lithium ion secondary batteries equipped with a non-aqueous electrolyte are commercialized as secondary batteries for portable devices such as mobile phones. This lithium ion secondary battery uses lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, a carbon material as a negative electrode active material, an organic solvent in which a lithium salt is dissolved in a non-aqueous electrolyte, and a porous film as a separator Has been. With the recent thinning of portable devices, thinning of non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries has been studied.

  By the way, with the rapid spread of digital devices, the importance of electromagnetic wave countermeasures has increased, and since the operating frequency of recent CPUs of personal computers has reached 1 GHz or higher, a new electromagnetic wave countermeasure to replace the current electromagnetic wave countermeasures is awaited. It is.

  An object of the present invention is to provide a display function-equipped electronic device including an electromagnetic wave shielding material excellent in an electromagnetic wave shielding effect.

The present invention is a display function-equipped electronic device comprising a central processing unit, a display device unit, and an electromagnetic wave shielding material disposed on the back surface of the display device unit,
Satisfying the following formula (1),
The electromagnetic shielding material includes a protection circuit, and a battery pack of a thin nonaqueous electrolyte secondary battery that is connected to the protection circuit and is disposed with the protection circuit interposed therebetween,
The thin non-aqueous electrolyte secondary battery includes an electrode group wound in a flat shape with a separator interposed between a positive electrode and a negative electrode, a non-aqueous electrolyte containing γ-butyrolactone, the electrode group, and the non-aqueous electrolyte. A display function-equipped electronic device.

100 ≦ X / Y ≦ 50000 (1)
However, in said Formula (1), said X is the operating frequency (MHz) of the calculating part of the said central processing unit, and said Y is the capacity | capacitance (Ah) of the said thin nonaqueous electrolyte secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the display function mounting type electronic device provided with the electromagnetic wave shielding material in which the electromagnetic wave shielding effect was improved can be provided.

  The electromagnetic wave shielding material according to the present invention includes a container, an electrode group housed in the container, wound in a flat shape with a separator interposed between a positive electrode and a negative electrode, and a nonaqueous electrolyte held by the electrode group A plurality of thin non-aqueous electrolyte secondary batteries having a plurality of thin non-aqueous electrolyte secondary batteries, wherein the plurality of thin non-aqueous electrolyte secondary batteries are arranged such that winding directions of the electrode groups are directed in the same direction. To do.

  According to such an electromagnetic wave shielding material, the electromagnetic wave shielding effect can be enhanced. By arranging the winding direction of the electrode group to be the same direction, it is possible to optimize the action effect between the vicinity of the secondary batteries, improve the broadband and high magnetic loss characteristics, and high electromagnetic shielding The effect can be realized. For example, when the electromagnetic shielding effect when the number of secondary batteries constituting the shield material is one is 0.5, two secondary batteries are arranged so that the winding directions of the electrode groups are the same. When the electromagnetic shielding effect is 3 and two secondary batteries are arranged so that the winding directions of the electrode groups are different from each other, the electromagnetic shielding effect is 1.

  In the electromagnetic wave shielding material according to the present invention, the container of the thin non-aqueous electrolyte secondary battery is formed from a film material having a thickness of 0.5 mm or less including a metal layer and a resin layer, and γ- By containing butyrolactone, the electromagnetic wave shielding effect can be enhanced. Moreover, since it is possible to suppress the generation of gas in the secondary battery when the temperature of the shield material rises, it is possible to avoid deformation (swelling or the like) of the shield material when the temperature rises.

  A first display function-equipped electronic device according to the present invention includes a central processing unit, a display unit, and one or a plurality of thin non-aqueous electrolyte secondary batteries disposed on the back of the display unit. It comprises an electromagnetic wave shielding material and satisfies the following formula (1).

100 ≦ X / Y ≦ 50000 (1)
However, in said Formula (1), said X is the operating frequency (MHz) of the calculating part of the said central processing unit, and said Y is the capacity | capacitance (Ah) of the said thin nonaqueous electrolyte secondary battery.

  Here, the capacity (Ah) of the thin non-aqueous electrolyte secondary battery means the theoretical capacity (design capacity) of the thin non-aqueous electrolyte secondary battery.

  According to such a first display function-equipped electronic device, it is possible to reduce the influence of electromagnetic waves generated from the electronic device on the human body, and to stabilize the battery characteristics because noise becomes difficult to be applied to the battery output. can do. In addition, since the power source of the electronic device also serves as the electromagnetic shielding material, it is not necessary to provide a separate electromagnetic shielding space in the electronic device, and the device can be downsized. Furthermore, by arranging the electromagnetic shielding material on the back surface of the display device unit, the non-aqueous electrolyte secondary battery can be prevented from being heated by the heat generated by the CPU and the data recording device unit, and the secondary battery Since the heat dissipation efficiency can be increased, it is possible to suppress thermal degradation of the cycle characteristics and discharge characteristics of the nonaqueous electrolyte secondary battery.

  In the first display function-equipped electronic device according to the present invention, as the thin non-aqueous electrolyte secondary battery, a container formed using a film material having a thickness of 0.5 mm or less including a metal layer and a resin layer; By using an electrode group housed in the container and a non-aqueous electrolyte that is held in the electrode group and contains γ-butyrolactone, the electromagnetic wave shielding effect of the electromagnetic wave shielding material can be increased. . Moreover, since it is possible to suppress the generation of gas in the secondary battery when the temperature of the shield material rises, it is possible to avoid deformation (swelling or the like) of the shield material when the temperature rises.

A second display function-equipped electronic device according to the present invention is a display function-equipped electronic device including a display device section.
A thin non-aqueous electrolyte secondary having a container, an electrode group housed in the container and wound in a flat shape with a separator interposed between a positive electrode and a negative electrode, and a non-aqueous electrolyte held in the electrode group An electromagnetic shielding material comprising a plurality of batteries and in which the winding directions of the electrode groups of the plurality of thin non-aqueous electrolyte secondary batteries are aligned in the same direction is disposed on the back surface of the display device section. It is what.

  According to the second display function-equipped electronic device, the influence of electromagnetic waves generated from the electronic device on the human body can be reduced. In addition, since the power source of the electronic device also serves as the electromagnetic shielding material, it is not necessary to provide a separate electromagnetic shielding space in the electronic device, and the device can be downsized. Furthermore, by arranging the electromagnetic shielding material on the back surface of the display device unit, the non-aqueous electrolyte secondary battery can be prevented from being heated by the heat generated by the CPU and the data recording device unit, and the secondary battery Since the heat dissipation efficiency can be increased, it is possible to suppress thermal degradation of the cycle characteristics and discharge characteristics of the nonaqueous electrolyte secondary battery.

  In the second display function-equipped electronic device according to the present invention, the container of the thin non-aqueous electrolyte secondary battery is formed from a film material having a thickness of 0.5 mm or less including a metal layer and a resin layer, and By containing γ-butyrolactone in the non-aqueous electrolyte, the electromagnetic wave shielding effect can be enhanced. Moreover, since it is possible to suppress the generation of gas in the secondary battery when the temperature of the shield material rises, it is possible to avoid deformation (swelling or the like) of the shield material when the temperature rises.

  In the first to second display function-equipped electronic devices according to the present invention, the occupation area of the electromagnetic wave shielding material on the back surface of the display device section is set to 20% or more and 90% or less, whereby the electromagnetic wave shielding of the electromagnetic wave shielding material. The effect can be further increased.

  In the first to second display function-equipped electronic devices according to the present invention, when there are a plurality of thin nonaqueous electrolyte secondary batteries included in the electromagnetic wave shielding material, one thin nonaqueous electrolyte secondary battery is provided. When the area of the back surface of the display device unit is set to 1 within the range of 0.02 to 0.8 when the area facing the back surface of the display device unit is 1, the electromagnetic wave shielding effect of the electromagnetic wave shielding material is improved. It can be even higher.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

  Hereinafter, an example of the electromagnetic wave shielding material according to the present invention will be described with reference to FIGS.

  The electromagnetic shielding material 1 is composed of a thin secondary battery 2 such as a thin (flat type) non-aqueous electrolyte secondary battery (for example, a thin lithium ion secondary battery, a thin lithium secondary battery, a thin lithium polymer secondary battery). The battery pack includes a battery pack connected in series. The positive electrode lead 3 and the negative electrode lead 4 of each thin secondary battery are connected to a protection circuit 5.

  As shown in FIGS. 2 to 3, the thin non-aqueous electrolyte secondary battery 2 includes an electrode group 9 wound in a flat shape with a separator 8 interposed between a positive electrode 6 and a negative electrode 7, and the electrode group 9 Formed of a non-aqueous electrolyte held on the positive electrode 6, a positive electrode lead 3 connected to the positive electrode 6, a negative electrode lead 4 connected to the negative electrode 7, and a film material processed into a bag shape, and the electrode group 9 And a container 10 for sealing. Note that the positive electrode lead 3 and the negative electrode lead 4 have tips extending outside the outer package 10. The thickness X of the film material is preferably 0.5 mm or less. Moreover, in this electromagnetic wave shielding material 1, the winding direction P of the electrode group 9 faces the same direction. Furthermore, although the electromagnetic wave shielding material 1 may be used as it is exposed as shown in FIG. 1 described above, it can also be used in a state of being housed in a resin case or the like.

  According to the electromagnetic wave shielding material 1 according to the present invention as described above, the winding direction P of the electrode group 9 of the thin non-aqueous electrolyte secondary battery 2 is aligned in the same direction, so that the electromagnetic wave shielding effect is enhanced. be able to. Further, when the surface having the maximum area of the secondary battery 2 is opposed to the electromagnetic wave generation source, the electromagnetic wave shielding effect can be further enhanced.

  Hereinafter, the positive electrode 6, the negative electrode 7, the separator 8, the nonaqueous electrolyte, and the exterior material 10 will be described.

1) Positive electrode 6
The positive electrode is produced, for example, by suspending a conductive agent and a binder in an appropriate solvent in a positive electrode active material, and applying the suspension to a current collector such as an aluminum foil, drying, and pressing.

Examples of the positive electrode active material include various oxides and sulfides. For example, manganese dioxide (MnO ₂ ), lithium manganese composite oxide (eg LiMn ₂ O ₄ or LiMnO ₂ ), lithium nickel composite oxide (eg LiNiO ₂ ), lithium cobalt composite oxide (LiCoO ₂ ), lithium nickel cobalt composite Examples thereof include oxides (for example, LiNi _1-x Co _x O ₂ ), lithium manganese cobalt composite oxides (for example, LiMn _x Co _1-x O ₂ ), vanadium oxides (for example, V ₂ O ₅ ), and the like. Moreover, organic materials, such as a conductive polymer material and a disulfide-type polymer material, are also mentioned. Among the positive electrode active materials, lithium manganese composite oxide (LiMn ₂ O ₄ ), lithium nickel composite oxide (LiNiO ₂ ), lithium cobalt composite oxide (LiCoO ₂ ), and lithium nickel cobalt composite oxide having a high battery voltage are preferable. (LiNi _0.8 Co _0.2 O ₂ ), lithium manganese cobalt composite oxide (LiMn _x Co _1-x O ₂ ), and the like.

  Examples of the conductive agent include acetylene black, carbon black, and graphite.

  Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.

  The mixing ratio of the positive electrode active material, the conductive agent and the binder is preferably in the range of 80 to 95% by weight of the positive electrode active material, 3 to 20% by weight of the conductive agent, and 2 to 7% by weight of the binder.

2) Negative electrode 7
The negative electrode is produced, for example, by suspending a negative electrode active material, a conductive material and a binder in a suitable solvent, and applying, drying and pressing on a metal foil such as a copper foil.

Examples of the negative electrode active material include lithium metal, lithium alloys (for example, Li ₄ Ti ₅ O ₁₂ ), metal oxides (for example, amorphous tin oxide, WO ₂ , MoO _2, etc.), TiS ₂ , lithium ions. Examples thereof include carbonaceous materials that occlude / release. Of these, carbonaceous materials are preferred. Since the negative electrode containing this carbonaceous material can improve the charge / discharge efficiency of the negative electrode and reduce the negative electrode resistance accompanying charge / discharge, the cycle life and output characteristics of the nonaqueous electrolyte secondary battery can be greatly improved. Can be improved.

  Examples of the carbonaceous material include graphite, isotropic graphite, coke, carbon fiber, spherical carbon, resin-fired carbon, and pyrolytic vapor-grown carbon. Among them, a carbon fiber using mesophase pitch as a raw material and a negative electrode containing spherical carbon are preferable because they can improve cycle life because of high charging efficiency. Furthermore, the orientation of carbon fibers made from mesophase pitch or spherical carbon graphite crystals is preferably radial. Carbon fibers and spherical carbon made from mesophase pitch are carbonized by heat-treating raw materials such as petroleum pitch, coal tar and resin at 550 ° C. to 2000 ° C., or graphite by heat treatment at 2000 ° C. or higher. Can be produced.

The carbonaceous material is preferably surface spacing d ₀₀₂ of (002) plane of graphite crystal obtained from X-ray diffraction peaks in the range of 0.3354Nm～0.4Nm. The carbonaceous material preferably has a specific surface area of 0.5 m ² / g or more by the BET method. A more preferable range of the specific surface area is 1 m ² / g or more.

  Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), and the like. Can do.

3) Separator 8
As said separator, a synthetic resin nonwoven fabric, a polyethylene porous film, a polypropylene porous film etc. can be mentioned, for example.

4) Non-aqueous electrolyte The non-aqueous electrolyte includes a liquid non-aqueous electrolyte prepared by dissolving an electrolyte in a non-aqueous solvent, a gel-like non-aqueous electrolyte in which a polymer material, a non-aqueous solvent and an electrolyte are combined. Examples thereof include a solid non-aqueous electrolyte in which an electrolyte is held in a molecular material, and an inorganic solid electrolyte having lithium ion conductivity. Among these, it is preferable to use a liquid non-aqueous electrolyte due to various characteristics.

  As the non-aqueous solvent, a known non-aqueous solvent can be used, and a cyclic carbonate such as ethylene carbonate (EC) or propylene carbonate (PC), or a non-aqueous solvent having a viscosity lower than that of the cyclic carbonate and the cyclic carbonate (hereinafter referred to as second solvent). It is preferable to use a nonaqueous solvent mainly composed of a mixed solvent.

  Examples of the second solvent include chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate, γ-butyrolactone, acetonitrile, methyl propionate, ethyl propionate, cyclic ether such as tetrahydrofuran, and 2-methyltetrahydrofuran. Examples of the ether include dimethoxyethane and diethoxyethane.

  In particular, the non-aqueous solvent preferably contains γ-butyrolactone. A non-aqueous electrolyte containing such a non-aqueous solvent can improve lithium ion conductivity and stability under a high temperature environment. In particular, it is desirable to use a mixed solvent of EC and BL, EC and PC and BL, EC and BL and VC, EC and PC and BL and VC, EC and DEC, EC and PC and DEC as the nonaqueous solvent. It is preferable that the abundance ratio of EC in the six kinds of mixed solvents is in the range of 10 to 50% by volume.

  When using what contains (gamma) -butyrolactone (gamma BL) as a nonaqueous solvent, it is preferable that the volume ratio of (gamma) -butyrolactone (gammaBL) in a nonaqueous solvent shall be 50 volume% or more of the whole nonaqueous solvent. . Since the non-aqueous electrolyte provided with such a non-aqueous solvent has high thermal stability, abnormal heat generation of the battery can be suppressed and safety can be further improved. If the volume ratio of γBL is less than 50% by volume, the amount of gas generated at a high temperature increases, which may make it difficult to suppress swelling of the electromagnetic shielding material. Furthermore, when the solvent mixed with γBL is a cyclic carbonate (for example, ethylene carbonate), the volume ratio of the cyclic carbonate becomes relatively high, so that the solvent viscosity increases, the conductivity decreases, and the charge / discharge cycle characteristics. And the large current discharge characteristics deteriorate. In addition, if the volume ratio of γBL exceeds 95% by volume, a reaction between the negative electrode and γBL may occur, which may reduce charge / discharge cycle characteristics and safety. Therefore, the volume ratio of γBL in the non-aqueous solvent is 50%. It is preferable to be in the range of ~ 95% by volume. A more preferable range of the volume ratio of γBL is 55 volume% or more and 75 volume% or less. Within this range, the effect of suppressing gas generation during high-temperature storage becomes higher.

Examples of the electrolyte include alkali salts, and lithium salts are particularly preferable. As lithium salts, lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), lithium perchlorate (LiClO ₄ ), lithium trifluorometasulfonate (LiCF) ₃ SO ₃ ). In particular, lithium hexafluorophosphate (LiPF ₆ ) and lithium borofluoride (LiBF ₄ ) are preferable.

  The amount of the electrolyte dissolved in the non-aqueous solvent is preferably 0.5 to 2 mol / L.

5) Container 10
Examples of the film material constituting the container 10 include a metal film, a resin film such as a thermoplastic resin, and a composite film including a metal layer and a resin layer (for example, one or both surfaces of a flexible metal layer are heated. And a laminate film having a structure coated with a resin layer such as a plastic resin. Among these, a laminate film is desirable because it is lightweight, has high strength, can prevent moisture from entering from the outside, and can further enhance the shielding effect of electromagnetic waves.

  The metal film can be formed from, for example, aluminum, iron, stainless steel, nickel, or the like.

  The resin layer constituting the composite film can be formed from, for example, a thermoplastic resin. Examples of the thermoplastic resin include polyolefins such as polyethylene and polypropylene. The resin layer can be formed from one kind of resin or two or more kinds of resins.

  The metal layer of the composite film can be formed from, for example, aluminum, iron, stainless steel, nickel, or the like. The metal layer can be formed of one kind of metal or two or more kinds of metals. Among these, it is desirable to form from aluminum that can prevent water from entering the battery.

  The container manufactured using the composite film is sealed by, for example, heat sealing. For this reason, it is desirable to arrange a thermoplastic resin on the inner surface of the container. The melting point of the thermoplastic resin is preferably 120 ° C or higher, more preferably 140 ° C to 250 ° C. Examples of the thermoplastic resin include polyolefins such as polyethylene and polypropylene. In particular, it is desirable to use polypropylene having a melting point of 150 ° C. or higher because the sealing strength of the heat seal portion is increased.

  The thickness of the film material is preferably 0.01 mm or more and 0.5 mm or less. This is due to the following reason. If the thickness of the film material is less than 0.01 mm, the strength of the container may be insufficient. On the other hand, it is not preferable that the thickness of the film material exceeds 0.5 mm from the viewpoint of reducing the thickness and weight of the secondary battery. A more preferable range of the thickness of the film material is 0.05 mm or more and 0.3 mm or less.

  The thickness of the secondary battery is preferably 0.1 mm or more and 5 mm or less. This is due to the following reason. If the battery thickness is less than 0.1 mm, the strength of the secondary battery may be insufficient. On the other hand, if the battery thickness exceeds 5 mm, the volume energy density of the secondary battery may be lowered. A more preferable range of the battery thickness is 0.5 mm or more and 4.5 mm or less.

  1 to 3 described above, a flat electrode group wound in a flat shape with a separator interposed between the positive electrode and the negative electrode was used, but a plurality of positive electrodes, separators, and negative electrodes were laminated in this order. A flat electrode group or a flat electrode group bent with a separator interposed between the positive electrode and the negative electrode may be used.

  In addition, in FIGS. 1 to 3 described above, an example in which the present invention is applied to a thin nonaqueous electrolyte secondary battery including a bag-like container has been described, but a bottomed cylindrical or bottomed rectangular tube-shaped container is provided. The present invention can be similarly applied to a thin nonaqueous electrolyte secondary battery. The bottomed cylindrical shape and the bottomed rectangular tube-shaped container can be formed of, for example, aluminum, iron, stainless steel, nickel, or the like.

  Next, a display function-equipped electronic device including the electromagnetic wave shielding material according to the present invention will be described. An example of this display function-equipped electronic device is shown in FIGS.

  A notebook computer 11 as a display function-equipped electronic device includes a first main body (upper casing) 13 having a display device section 12, a keyboard input device section 14, and a central processing unit (CPU) (not shown). A main body (lower casing) 15 and a hinge portion 16 that connects the first main body 13 and the second main body 15 are provided. As shown in FIG. 5, the first main body 13 includes a display device unit 12, an electromagnetic wave shielding material 17 disposed on the back surface of the display device unit 12, and a housing 18 adjacent to the electromagnetic wave shielding material 17. Have For example, a liquid crystal display (LCD) can be adopted as the display device section 12 and includes a backlight, a circuit board and the like (not shown).

  The electromagnetic wave shielding material 17 includes two sets of assembled batteries in which three thin (flat type) nonaqueous electrolyte secondary batteries 2 are connected in series. The positive electrode 3 and the negative electrode 4 of each secondary battery 2 are connected to a protection circuit 5. The surface having the maximum area of each secondary battery 2 faces the back surface of the display device section 12. Furthermore, the winding direction P of the electrode group of each secondary battery is aligned in the same direction. The second main body 20 incorporates a DC-DC converter, a hard disk drive, a PC card slot, etc. (not shown) in addition to the keyboard input device unit 14 and the central processing unit (CPU) described above. Further, an external interface (not shown) for connecting a mouse, a printer or the like is attached to the rear side surface of the second main body 20.

  According to such a display function-equipped electronic device, the winding direction P of the electrode group of the secondary battery 2 constituting the electromagnetic wave shielding material 17 faces the same direction and has the maximum area of the secondary battery 2. Since the surface is opposed to the back surface of the display device portion, the electromagnetic wave shielding effect can be enhanced. Further, since the electromagnetic shielding material 17 also serves as a power source for the electronic device, the electronic device can be made smaller than the electromagnetic shielding material and the power source provided separately. Furthermore, the electromagnetic shielding material 17 is disposed on the back surface of the display device section 12, thereby preventing the nonaqueous electrolyte secondary battery 2 from being heated by the heat generated by the CPU and the data recording device section in the second main body 15. In addition, since the heat dissipation efficiency of the secondary battery 2 can be increased, it is possible to suppress thermal degradation of the cycle characteristics and the discharge characteristics of the nonaqueous electrolyte secondary battery 2.

  The display function-equipped electronic device preferably satisfies the following formula (1).

100 ≦ X / Y ≦ 50000 (1)
However, in said (1) Formula, said X is the operating frequency (MHz) of the calculating part of the said central processing unit, and said Y is the discharge capacity (Ah) of each said thin nonaqueous electrolyte secondary battery 2. FIG.

  If X / Y is less than 100, there is a risk that noise will be applied to the battery output and the battery characteristics will become unstable. On the other hand, when X / Y exceeds 50000, the electromagnetic wave shielding material 17 may not be able to obtain a high electromagnetic wave shielding effect. A more preferable range is 500 ≦ X / Y ≦ 10000.

  In the display function-equipped electronic device, it is desirable that the occupation area of the electromagnetic wave shielding material 17 on the back surface of the display device unit 12 is 20% or more and 90% or less. This is because if the occupied area is out of the above range, the electromagnetic wave shielding material 17 may not be able to obtain a high electromagnetic wave shielding effect. A more preferable range of the occupied area is 25% or more and 80% or less.

  In the display function-equipped electronic device, the facing area of the thin nonaqueous electrolyte secondary battery with respect to the back surface of the display device unit 12 is 0 when the area of the back surface of the display device unit 12 is 1. It is preferable to be in the range of 02 or more and 0.8 or less. This is because if the opposing area when the back surface area of the display device unit is 1 is out of the above range, the electromagnetic wave shielding material 17 may not be able to obtain a high electromagnetic wave shielding effect. A more preferable range of the facing area when the back surface area of the display device unit is 1 is 0.05 or more and 0.6 or less.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1
An electrode group was prepared by winding a flat shape with a separator interposed between a positive electrode containing an active material such as a lithium-containing composite oxide and a negative electrode containing a carbonaceous material that occludes and releases lithium ions. Moreover, 1.5 mol / L of lithium tetrafluoroborate (LiBF ₄ ) was dissolved in a mixed solvent of ethylene carbonate (EC) and γ-butyrolactone (γBL) (mixed volume ratio 40:60) to form a liquid non-aqueous electrolyte. Was prepared. On the other hand, a laminate film having a thickness of 0.1 mm in which both surfaces of an aluminum foil were covered with polypropylene was prepared and formed into a bag shape to obtain a container. The flat electrode group was accommodated in this and subjected to a heating press.

  Next, after vacuum drying the electrode group in the laminated film bag, the liquid nonaqueous electrolyte was injected, and the positive electrode lead and the negative electrode lead were extended to the outside of the laminated film bag. By heat-sealing the opening, a thin nonaqueous electrolyte secondary battery having the structure shown in FIGS. 2 and 3 and having a thickness of 3.6 mm and a theoretical capacity Y of 1 Ah was assembled.

  By connecting three obtained secondary batteries in series, the secondary batteries are arranged with the winding direction of the electrode group in the same direction, and the assembled battery is assembled by connecting a protective circuit to the positive electrode lead and the negative electrode lead. An electromagnetic shielding material was obtained.

  A notebook computer having the structure shown in FIG. 4 and having an operating frequency X of 1000 (MHz) of the arithmetic processing unit of the central processing unit is prepared. It arrange | positioned so that the surface which has the largest area may oppose the back surface of a display apparatus part. The area occupied by the electromagnetic shielding material on the back surface of the display unit was 20%. Further, when the area of the back surface of the display device unit is 1, the facing area of each secondary battery with the back surface of the display device unit (in this case, equal to the area of the surface having the maximum area of the secondary battery) is 0.2.

(Comparative Example 1)
Among the three thin non-aqueous electrolyte secondary batteries constituting the electromagnetic shielding material, the winding direction of the electrode group of the secondary battery adjacent to the electrode group winding direction of the thin non-aqueous electrolyte secondary battery located in the middle An electromagnetic shielding material having the same configuration as in Example 1 was prepared except that the above was reversed.

(Comparative Example 2)
One thin non-aqueous electrolyte secondary battery having the same configuration as in Example 1 was prepared and used as an electromagnetic shielding material.

About the electromagnetic wave shielding material of Example 1 and Comparative Examples 1 and 2, in an electromagnetic dark room, an electromagnetic wave of 30 MHz to 1 GHz is irradiated on one surface of the electromagnetic wave shielding material, and the electromagnetic wave shielding material is transmitted at 300 to 800 MHz. The resulting level of electromagnetic radiation noise was measured and the results are shown in Table 1 below. However, in this test, the winding direction of the electrode group of the three secondary batteries constituting the electromagnetic shielding material of Example 1 and the three secondary batteries constituting the electromagnetic shielding material of Comparative Example 1 The winding direction of the electrode group of the secondary battery located at both ends and the winding direction of the electrode group of the secondary battery constituting the electromagnetic shielding material of Comparative Example 2 were combined.

(Example 2)
Except for changing the value of X / Y as shown in Table 2 below by changing the theoretical capacity Y of the thin non-aqueous electrolyte secondary battery to 0.8 Ah, the configuration is the same as that of Example 1 described above. A notebook computer was prepared.

(Example 3)
A notebook type having the same configuration as that of Example 1 described above except that the value of X / Y is changed as shown in Table 2 below by changing the theoretical capacity Y of the thin non-aqueous electrolyte secondary battery to 2 Ah. A computer was prepared.

Example 4
Except for changing the value of X / Y as shown in Table 2 below by changing the theoretical capacity Y of the thin non-aqueous electrolyte secondary battery to 1 Ah and changing the operating frequency X to 10,000, the above-described embodiment A notebook computer having the same configuration as that of No. 1 was prepared.

(Example 5)
Except for changing the value of X / Y as shown in Table 2 below by changing the theoretical capacity Y of the thin non-aqueous electrolyte secondary battery to 0.1 Ah and changing the operating frequency X to 5000. A notebook computer having the same configuration as that of Example 1 was prepared.

(Example 6)
Except for changing the occupation area of the electromagnetic wave shield on the back surface of the display unit as shown in Table 2 below, by changing the number of secondary batteries constituting the electromagnetic wave shield to 6, A notebook computer with the same configuration was prepared.

(Example 7)
Except for changing the occupation area of the electromagnetic wave shield on the back surface of the display unit as shown in Table 2 below by changing the number of secondary batteries constituting the electromagnetic wave shield to nine, A notebook computer with the same configuration was prepared.

(Example 8)
Except for changing the occupation area of the electromagnetic wave shield on the back surface of the display unit as shown in Table 2 below by changing the number of secondary batteries constituting the electromagnetic wave shield to 12, A notebook computer with the same configuration was prepared.

Example 9
By changing the theoretical capacity Y of the secondary battery constituting the electromagnetic wave shield to 0.5 Ah and changing the number of secondary batteries to nine, the facing area of each secondary battery with the back of the display unit is as follows: A notebook computer having the same configuration as that of Example 1 described above was prepared except that the changes were made as shown in Table 2.

(Example 10)
By changing the theoretical capacity Y of the secondary battery constituting the electromagnetic wave shield to 1.5 Ah and changing the number of secondary batteries to 6, the opposing area of each secondary battery with the back of the display unit is as follows: A notebook computer having the same configuration as that of Example 1 described above was prepared except that the changes were made as shown in Table 2.

(Example 11)
By changing the theoretical capacity Y of the secondary battery constituting the electromagnetic wave shield to 3 Ah and changing the number of secondary batteries to 3, the opposing area of each secondary battery with the back of the display unit is shown in Table 2 below. A notebook computer having the same configuration as that of the first embodiment described above was prepared except that the changes were made as shown in FIG.

(Comparative Example 3)
A known notebook computer in which an electromagnetic wave shielding material is not mounted and a battery pack of a thin non-aqueous electrolyte secondary battery is built in a second main body (lower casing) was prepared. A ferrite material was disposed as an electromagnetic wave shielding material on the back of the first main body (upper casing) of the notebook computer.

For the notebook computers of Examples 1 to 11 and Comparative Example 3, radiation noise from 30 MHz to 1 GHz was measured in an anechoic chamber, and the average value obtained at 300 to 800 MHz was taken as the electromagnetic wave shielding effect. The level obtained in Comparative Example 3 is set to 1 due to the electromagnetic wave shielding effect. The results are shown in Table 2 below.

  As is clear from Table 2, it can be seen that the notebook computer equipped with the electromagnetic shielding materials of Examples 1 to 11 can have an electromagnetic shielding effect higher than that of Comparative Example 3.

The schematic diagram which shows an example of the electromagnetic wave shielding material which concerns on this invention. The partial notch perspective view which shows the thin nonaqueous electrolyte secondary battery of FIG. Sectional drawing which shows the thin non-aqueous electrolyte secondary battery of FIG. The schematic diagram which shows an example of the electronic device with a display function which concerns on this invention. FIG. 5 is an exploded view showing a first main body (upper casing) included in the display function-equipped electronic device of FIG. 4.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electromagnetic shielding material, 2 ... Thin nonaqueous electrolyte secondary battery, 3 ... Positive electrode lead, 4 ... Negative electrode lead, 5 ... Protection circuit, 6 ... Positive electrode, 7 ... Negative electrode, 8 ... Separator, 9 ... Electrode group, 10 ... A container, 11 ... a notebook computer, 12 ... a display device part, 13 ... a first main body, 14 ... a keyboard input device part, 15 ... a second main body (lower casing), 17 ... an electromagnetic wave shield.

Claims (3)

A display-function-equipped electronic device comprising a central processing unit, a display device unit, and an electromagnetic wave shielding material disposed on the back surface of the display device unit,
Satisfying the following formula (1),
The electromagnetic shielding material includes a protection circuit, and a battery pack of a thin nonaqueous electrolyte secondary battery that is connected to the protection circuit and is disposed with the protection circuit interposed therebetween,
The thin non-aqueous electrolyte secondary battery includes an electrode group wound in a flat shape with a separator interposed between a positive electrode and a negative electrode, a non-aqueous electrolyte containing γ-butyrolactone, the electrode group, and the non-aqueous electrolyte. A display-function-equipped electronic device, comprising:
100 ≦ X / Y ≦ 50000 (1)
However, in said Formula (1), said X is the operating frequency (MHz) of the calculating part of the said central processing unit, and said Y is the capacity | capacitance (Ah) of the said thin nonaqueous electrolyte secondary battery.   2. The display function-equipped electronic device according to claim 1, wherein the container is formed using a film material having a thickness of 0.5 mm or less including a metal layer and a resin layer.   3. The display function-equipped electronic device according to claim 1, wherein a thickness of the thin non-aqueous electrolyte secondary battery is 0.1 mm or more and 5 mm or less.

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