JP6705322B2 - Lead wire for electric parts and electric parts - Google Patents

Description

The present invention relates to a lead wire for electric parts and an electric part.

Along with the demand for miniaturization of electronic devices, there is an increasing demand for miniaturization and weight reduction of batteries used as power sources thereof. On the other hand, higher energy density and higher energy efficiency for batteries are also required. In order to meet these requirements, expectations are increasing for non-aqueous electrolyte batteries (for example, lithium ion batteries) in which electrodes, an electrolytic solution, and the like are enclosed inside a bag body mainly made of synthetic resin or the like.

In such a non-aqueous electrolyte battery, in general, a lead wire extends from the bag in order to take out an electric current to the outside. As the lead wire, not only a lead wire made of a metal such as aluminum but also a lead wire covered with an insulating layer of a thermoplastic resin is known. The lead wire is attached to the bag body, for example, by heat-sealing the open end portion of the bag body with the inner surface of the open end portion sandwiching the lead wire.

In such a method of attaching the lead conductor to the bag body by heat sealing, the insulating layer may be melted at the time of heating during heat sealing, and the lead conductor may be short-circuited with the metal layer of the bag body. Therefore, it has been proposed to prevent the melting of the insulating layer by making the insulating layer include a crosslinked layer made of crosslinked polyolefin (see, for example, Patent Documents 1 and 2).

JP, 2001-102016, A JP, 2009-259739, A

The non-aqueous electrolyte battery including the conventional lead wire is often housed in an electronic device with the lead wire bent. Therefore, at the time of manufacturing the electronic device, the lead wire included in the non-aqueous electrolyte battery is bent at a position where the lead conductor is covered with an insulating layer, and may be sent to a downstream process while maintaining the bent shape. is there. Therefore, when it is assumed that the lead wire is bent and used, there is a demand for a lead wire in which springback is unlikely to occur and the bent shape can be preferably maintained.

Here, the lead conductor is made of metal such as aluminum, and when it is bent, it is plastically deformed to generate a force for holding the bent shape. On the other hand, since the insulating layer is made of resin or the like, when it is bent, it is elastically deformed and a force is generated to restore the bent shape to the original shape. If the force that returns from the bent shape due to the elastic deformation of the insulating layer to the original shape is stronger than the other two forces, the lead wire cannot hold the bent shape and the original shape is slightly increased. The phenomenon of returning to the shape (spring back) occurs. However, springback is a complicated phenomenon caused by the interaction of two members made of different materials, that is, the metal lead conductor and the resin insulating layer. Therefore, what kind of member is used for the lead conductor and the insulating layer is the springback. It is difficult to accurately predict whether or not can be suppressed.

Therefore, it is an object of the present invention to provide a lead wire for an electric component and an electric component in which a springback is unlikely to occur when used in bending and a bent shape can be preferably maintained.

An electrical component lead wire according to an aspect of the present invention is an electrical component lead wire including a strip conductor and a pair of insulating films that cover both surfaces of the strip conductor, wherein the strip conductor has elasticity. The modulus is D _m [Pa], the second moment of area per 1 mm width is I _m [m ⁴ /1 mm], and the average elastic modulus of the pair of insulating films is D _i [Pa], the second cross section per 1 mm width. When the secondary moment is I _i [m ⁴ /1 mm], the following formula (2) for the shape retention force H [N·m ² /1 mm] per 1 mm width of the strip-shaped conductor represented by the following formula (1) The ratio (R/H) of the elastic recovery force R [N·m ² /1 mm] per 1 mm of the width of the insulating film represented by) is 0.15 or less.
H=D _m ×I _m (1)
R=D _i ×I _i (2)

An electrical component according to an aspect of the present invention includes the electrical component lead wire.

According to the above invention, it is possible to provide a lead wire for an electric component, which is less likely to cause springback when used in bending, and which can maintain a preferable bent shape, and an electric component which is excellent in work efficiency.

FIG. 1 is a schematic perspective view showing a part of the lithium-ion battery according to another embodiment of the present invention with a part broken away. FIG. 2 is a schematic cross-sectional view taken along the line AA of FIG. FIG. 3A is a schematic cross-sectional view in the longitudinal direction for explaining the second moment of area of the strip-shaped conductor and the insulating film in the lead wire for an electric component according to an aspect of the present invention. FIG. 3B is a schematic cross-sectional view showing only the strip-shaped conductor of the lead wire for an electric component of FIG. 3A. FIG. 3C is a schematic cross-sectional view showing only the insulating film of the lead wire for electric component of FIG. 3A. FIG. 4A is a schematic plan view for explaining the lead wire used for evaluating the springback angle. 4B is a schematic cross-sectional view of the lead wire of FIG. 4A. FIG. 5A is a schematic cross-sectional view for explaining one step of the springback angle evaluation method. FIG. 5B is a schematic cross-sectional view for explaining the next step of FIG. 5A. FIG. 6 shows the relationship between the measurement result of the springback angle and the ratio (R/H) of the elastic recovery force R per 1 mm width of the pair of insulating films to the shape retention force H per 1 mm width of the strip-shaped conductor. It is a graph.

[Description of Embodiments of the Present Invention]
An electrical component lead wire according to an aspect of the present invention is an electrical component lead wire including a strip conductor and a pair of insulating films that cover both surfaces of the strip conductor, wherein the strip conductor has elasticity. The modulus is D _m [Pa], the second moment of area per 1 mm width is I _m [m ⁴ /1 mm], and the average elastic modulus of the pair of insulating films is D _i [Pa], the second cross section per 1 mm width. When the secondary moment is I _i [m ⁴ /1 mm], the following formula (2) for the shape retention force H [N·m ² /1 mm] per 1 mm width of the strip-shaped conductor represented by the following formula (1) The ratio (R/H) of the elastic recovery force R [N·m ² /1 mm] per 1 mm of the width of the insulating film represented by) is 0.15 or less.
H=D _m ×I _m (1)
R=D _i ×I _i (2)

Here, the reason why springback occurs in the lead wire is that the bending shape caused by the elastic deformation of the insulating film is more original than the force for holding the bending shape caused by the plastic deformation of the strip-shaped conductor as described above. It is considered that this is because the force to return to the shape acts stronger. Therefore, if the force due to the plastic deformation of the strip-shaped conductor is increased, while the force due to the elastic deformation of the insulating film is reduced, it is considered that springback is suppressed and the bent shape of the lead wire is easily maintained. .. Here, it is considered that whether or not the lead wire can maintain the bent shape, that is, the easiness of occurrence of springback depends not only on the material of the strip-shaped conductor or the insulating film but also on the thickness and shape thereof. Therefore, the inventors of the present invention express the influence of the strip-shaped conductor of the lead wire for an electric component on the spring back by the above mathematical expression (1) with the elastic modulus and the second moment of area per 1 mm width as parameters. It was found that it can be judged by the shape retention force per 1 mm width. In addition, the inventors of the present invention have shown that the effect of the insulating film of the lead wire for an electric component on springback is represented by the above formula (2) with the elastic modulus and the second moment of area per 1 mm width as parameters. It was found that it can be judged by the elastic recovery force per 1 mm. Furthermore, the present inventors have studied the influence of the insulating film and the strip-shaped conductor of the electrical component lead wire on the springback by elastic recovery per 1 mm width of the pair of insulating films with respect to the shape-retaining force per 1 mm width of the strip-shaped conductor. It has been found that by relating to the force ratio and setting the ratio to the above upper limit or less, springback is less likely to occur during bending and use, and the bent shape can be maintained appropriately.

As described above, in the electrical component lead wire, springback occurs by setting the ratio of the elastic recovery force per 1 mm width of the pair of insulating films to the shape retention force per 1 mm width of the strip-shaped conductor to the above upper limit or less. It is difficult and the bent shape can be maintained appropriately. Therefore, when the lead wire is bent and used, the bent shape is easily maintained, and therefore it is not necessary to fix the bent lead wire to another element using a fixing tape or the like after the lead wire is bent. As a result, the electric component lead wire can be simplified in the manufacturing process when it is bent and used, and it can contribute to space saving by being bent and used.

Here, the “average thickness” means an average value of thicknesses measured at arbitrary 5 points. The “elastic modulus” refers to the rising slope of the SS curve (stress-strain curve) when tensile deformation is applied to the strip-shaped conductor and the insulating film by using a precision universal testing machine (tensile testing machine). In the measurement of the elastic modulus, the sample gripping (chuck) interval of the tensile tester is set to 50 mm, and the sample is pulled at 50 mm/min. However, when measuring the elastic modulus of the strip conductor, in order to consider the effect of slip between the sample and the grip of the tester, a strain gauge capable of measuring minute displacement shall be attached to the sample for measurement. To do. In addition, what is directly obtained by the measurement of the elastic modulus is (test force [N]-movement distance [mm] curve), but the sample size and the chuck interval are determined by the following mathematical expressions (3) and (4). It is used to convert into (stress [Pa]-strain [%] curve) to obtain the elastic modulus. Further, even when the strip-shaped conductor and the insulating film have a multilayer structure, the elastic modulus can be obtained by the method described above. Furthermore, the “average elastic modulus of a pair of insulating films” means the average of the measured elastic moduli of the two insulating films. Hereinafter, the terms "average thickness" and "elastic modulus" are defined similarly.
Stress [Pa]=Test force [N]/Width [mm]/Thickness [mm] (3)
Distortion [%]=moving distance [mm]/chuck interval [mm]×100 (4)

The lead wire for an electric component may have a bending return angle of 20° or less after being bent by 180°. With such a lead wire, since the bending return angle after bending by 180°, that is, the springback angle is 20° or less, the bent shape can be more preferably maintained, and therefore the lead wire is bent and the shape is maintained. The work to do is easier and the workability is improved.

The elastic recovery force R is preferably 3.0×10 ⁻⁵ N·m ² /1 mm or more and 6.0×10 ⁻³ N·m ² /1 mm or less. According to such a lead wire, since the elastic recovery force R is in the above range, the springback after bending the lead wire for an electric component can be appropriately reduced. As a result, the bending work of the lead wire for the electric component is easier, and the workability is further improved.

The shape retention force H is preferably 3.0×10 ⁻⁴ N·m ² /1 mm or more and 6.0×10 ⁻² N·m ² /1 mm or less. According to such a lead wire, since the shape-retaining force H is within the above range, the bent shape can be more favorably maintained, and thus the lead wire for an electric component has a shape-retaining property capable of appropriately maintaining the bent shape. Can be given. As a result, the bending work of the lead wire for the electric component is easier, and the workability is further improved.

The average thickness of the strip conductor is preferably 30 μm or more and 200 μm or less, and the elastic modulus of the strip conductor is preferably 50 GPa or more and 300 GPa or less. According to such a lead wire, the shape-retaining force of the strip-shaped conductor can be set in a suitable range, and shape retention can be imparted to the lead wire for an electric component, which can appropriately maintain the bent shape. As a result, the bending work of the lead wire for the electric component is easier, and the workability is further improved.

The average thickness of each insulating film is preferably 25 μm or more and 200 μm or less, and the elastic modulus of each insulating film is preferably 100 MPa or more and 1400 MPa or less. According to such a lead wire, the elastic recovery force of the insulating film can be set in a suitable range, and the springback after bending the lead wire for an electric component can be appropriately reduced. As a result, the work of bending the lead wire for the electric component becomes easier, and the workability is further improved.

An electrical component according to an aspect of the present invention includes the electrical component lead wire. Since the electric component includes the lead wire for the electric component, it is possible to simplify the work of bending the lead wire for the electric component and maintaining the shape thereof, thereby improving work efficiency.

The electric component may be a non-aqueous electrolyte battery. As described above, since the electric component is excellent in work efficiency, it can be suitably used as a non-aqueous electrolyte battery.

[Details of the embodiment of the present invention]
Specific examples of lead wires for electric parts and electric parts according to embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to these exemplifications, and is shown by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

<Lead wire for electrical parts>
As shown in FIGS. 1 and 2, a lead wire 1 for an electric component according to an embodiment of the present invention includes a strip conductor 2 and a pair of insulating films 3 covering both sides of the strip conductor 2.

(Strip conductor)
The strip-shaped conductor 2 is connected to the electrodes (the positive electrode 5A and the negative electrode 5B) of an electric component such as the lithium-ion battery 4 and the like. The strip conductor 2 is made of a highly conductive material. Examples of such highly conductive materials include metal materials such as aluminum, titanium, nickel, copper, aluminum alloys, titanium alloys, nickel alloys, and copper alloys, and materials obtained by plating these metal materials with nickel, gold, or the like. Is mentioned. As a material for forming the strip-shaped conductor 2 connected to the positive electrode 5A of the electric component such as the lithium-ion battery 4, a material that does not dissolve during discharge, specifically, aluminum, titanium, an aluminum alloy and a titanium alloy are preferable. On the other hand, as a material for forming the strip-shaped conductor 2 connected to the negative electrode 5B, nickel, copper, nickel alloy, copper alloy, nickel-plated copper and gold-plated copper are preferable. The strip conductor 2 may be subjected to a surface treatment such as a chromate treatment, a trivalent chromium treatment, a non-chromate treatment, and a surface roughening treatment in order to improve resistance to the electrolytic solution. By such surface treatment, the electrolytic solution resistance of the strip-shaped conductor 2 can be improved.

When the elastic modulus of the strip-shaped conductor 2 is D _m [Pa] and the second moment of area per 1 mm of width is I _m [m ⁴ /1 mm], the width of the strip-shaped conductor 2 represented by the following mathematical formula (1). As a lower limit of the shape retention force H [N·m ² /1 mm] per 1 mm, 3.0×10 ⁻⁴ N·m ² /1 mm is preferable, and 2.0×10 ⁻³ N·m ² /1 mm. Is more preferable. The upper limit of the shape-retaining force H is preferably 6.0×10 ⁻² N·m ² /1 mm, more preferably 1.0×10 ⁻² N·m ² /1 mm.
H=D _m ×I _m (1)

When the shape-retaining force H is within the above range, the strip-shaped conductor 2 can more favorably maintain the bent shape, and therefore, the shape-retaining property that can appropriately maintain the bent shape can be imparted to the electrical component lead wire 1. As a result, the work of bending the electric component lead wire 1 and maintaining the shape thereof becomes easier, and the workability is further improved.

Here, a method for obtaining a geometrical moment of inertia per 1 mm width of the strip-shaped conductor 2 in the mathematical formula (1) and a cross-sectional moment per 1 mm of width of the pair of insulating films 3 in the mathematical formula (2) described later is illustrated. The lead wire 11 for electric parts of 3A will be described as an example. In the electrical component lead wire 11 illustrated in FIG. 3A, the pair of insulating films 13 have the same average thickness and the same average width. Let T be the average thickness of the lead wire 11 for an electric component, T _m [m] be the average thickness of the strip-shaped conductor 12, and T _i [m] be the average thickness of each of the pair of insulating films 13. The average width of the strip-shaped conductor 12 is W _m [m], and the average width of the pair of insulating films 13 is W _i [m]. Furthermore, the surface that bisects the electrical component lead wire 11 in the thickness direction (the surface that bisects the strip-shaped conductor 12 in the thickness direction) is regarded as the center plane M of the bending deformation of the electrical component lead wire 11. be able to.

Next, the sectional moment of the strip-shaped conductor 12 can be calculated by the following mathematical expression (5) based on the sectional shape shown in FIG. 3B. Similarly, the sectional moment of the pair of insulating films 13 can be calculated by the following mathematical expression (6) based on the sectional shape shown in FIG. 3C.
Second moment of area per 1 mm of width of strip conductor [m ⁴ /1 mm]=1/12×average width of strip conductor W _m [m]×(average thickness of strip conductor T _m [m]) ³ / Average width W _m [mm] of the strip conductor (5)
Second moment of area per 1 mm width of a pair of insulating films [m ⁴ /1 mm]=1/12×average width W _i [m]×{(average thickness T[m of electrical component lead wires ^{]) 3} - (average thickness of the strip-shaped conductor ^{_{T m [m]) 3}}} / the average width _W i [mm a pair of insulating film] (6)

When the average thickness or the average width of the pair of insulating films 3 of the electrical component lead wire 1 is not the same, the average value of the average thickness or the average width of the pair of insulating films 3 is calculated, and the average value of the pair of insulating films 3 is calculated. The above calculation is performed assuming that the average thickness or the average width is the average value. Then, the shape retention force H and the elastic recovery force R are obtained by using the second moment of area per 1 mm width of the strip conductor 2 and the pair of insulating films 3 obtained by this calculation.

The lower limit of the sectional moment per 1 mm of the width of the strip-shaped conductor 2 is preferably 5.0×10 ⁻¹⁵ m ⁴ /1 mm, more preferably 2.0×10 ⁻¹⁴ m ⁴ /1 mm. On the other hand, the upper limit of the above-mentioned sectional moment is preferably 8.0×10 ⁻¹³ m ⁴ /1 mm, more preferably 1.0×10 ⁻¹³ m ⁴ /1 mm. When the sectional moment is in the above range, the shape retaining force H per 1 mm width of the strip-shaped conductor 2 can be easily and reliably adjusted to the above range.

The average thickness of the strip conductor 2 is preferably 30 μm or more and 200 μm or less. The lower limit of the average thickness of the strip conductor 2 is more preferably 40 μm, further preferably 47 μm. On the other hand, the upper limit of the average thickness of the strip-shaped conductor 2 is more preferably 150 μm, further preferably 120 μm. When the average thickness of the strip-shaped conductor 2 is less than the above lower limit, the electric resistance value of the lead wire 1 for electric parts may increase. On the contrary, when the average thickness exceeds the upper limit, the electric component lead wire 1 becomes unnecessarily thick, and there is a possibility that the demand for thinning cannot be sufficiently satisfied.

The elastic modulus of the strip conductor 2 is preferably 50 GPa or more and 300 GPa or less. As the lower limit of the elastic modulus of the strip conductor 2, 60 GPa is more preferable, and 67 GPa is further preferable. On the other hand, as the upper limit of the elastic modulus of the strip conductor 2, 250 GPa is more preferable, and 210 GPa is further preferable. When the elastic modulus of the strip-shaped conductor 2 is less than the above lower limit, it may be difficult to suppress springback of the lead wire 1 for electric parts. On the other hand, when the elastic modulus exceeds the upper limit, workability may be deteriorated because force is required to bend the electric component lead wire 1. The elastic modulus of the strip conductor 2 can be adjusted by changing the material thereof, and particularly when the strip conductor 2 is made of an alloy, it can be finely adjusted by changing the alloy composition.

In addition, the strip-shaped conductor 2 has an average thickness of 30 μm or more and 200 μm or less and an elastic modulus of 50 GPa or more and 300 GPa or less, so that the shape-retaining force H is in a suitable range and the lead wire 1 for an electric component is bent. It is possible to impart shape-retaining property capable of appropriately maintaining the shape. As a result, the work of fixing the shape of the lead wire 1 for an electric component at the time of bending becomes easier and the workability is further improved.

(A pair of insulating films)
The pair of insulating films 3 covers both sides of the central portion of the strip-shaped conductor 2 in a state where both ends of the strip-shaped conductor 2 are exposed. For example, a bag body 6 of an electric component such as a lithium-ion battery 4 or the like. It is the part that is fixed to.

Each insulating film 3 is formed of a resin material having a high insulating property. This resin material is preferably a resin material having high adhesiveness to the strip-shaped conductor 2 or a resin material which is not easily melted by heating when the bag body 6 is heat-sealed.

Examples of the resin material having high adhesiveness to the strip-shaped conductor 2 include thermoplastic polyolefin. Examples of the thermoplastic polyolefin include polyethylene, acid-modified polyethylene, polypropylene, acid-modified polypropylene (for example, maleic anhydride-modified polypropylene), reactive resins such as ionomers, and mixtures thereof.

On the other hand, examples of the resin material that is difficult to melt due to heating when heat-sealing the bag body 6 include cross-linked polyolefin. As the crosslinked polyolefin, the one obtained by crosslinking the above-exemplified polyolefin can be used. As a method for crosslinking the polyolefin, crosslinking by irradiation with ionizing radiation such as electron beam or gamma ray, chemical crosslinking by peroxide or the like, silane crosslinking or the like is used. When a polyolefin is crosslinked by ionizing radiation, a crosslinking aid is added to the polyolefin as necessary. As the crosslinking aid, for example, trimethylolpropane methacrylate, pentaerythritol triacrylate, ethyne glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate and the like are used.

The gel fraction in the crosslinked polyolefin is preferably 20% or more and 90% or less. The gel fraction is an index showing the degree of cross-linking, and refers to the proportion of gel (insoluble polymer chain) in the cross-linked polyolefin that has become insoluble in a solvent such as xylene. When the gel fraction is less than 20%, the degree of crosslinking is insufficient and the insulating film 3 may melt during heat sealing. On the other hand, when the gel fraction exceeds 90%, the degree of cross-linking is too large, and the adhesiveness to the bag body 6 or the like may be deteriorated.

Further, each insulating film 3 may be a single layer or may be laminated in a plurality of layers. When the insulating film 3 is composed of a plurality of layers, it is formed of an insulating layer formed of a resin material having high adhesiveness to the strip-shaped conductor 2 and a resin material that is difficult to melt due to heating when the bag body 6 is heat-sealed. And an insulating layer. When the insulating film 3 having such a laminated structure is adopted, the adhesiveness to the strip-shaped conductor 2 can be ensured and, at the same time, the melting at the time of heat sealing can be prevented.

When the average elastic modulus of the pair of insulating films 3 is D _i [Pa] and the second moment of area per width 1 mm is I _i [m ⁴ /1 mm], the pair of insulating films represented by the following formula (2) As a lower limit of the elastic recovery force R [N·m ² /1 mm] per 1 mm of width 3, 3.0×10 ⁻⁵ N·m ² /1 mm is preferable, and 1.0×10 ⁻⁴ N·m. ² / 1mm is more preferable. On the other hand, the upper limit value of the elastic recovery force R is preferably 6.0×10 ⁻³ N·m ² /1 mm, more preferably 1.0×10 ⁻³ N·m ² /1 mm.
R=D _i ×I _i (2)

When the elastic recovery force per width of 1 mm of the pair of insulating films 3 is within the above range, spring back of the electrical component lead wire 1 after bending can be appropriately suppressed. As a result, the work of bending the electric component lead wire 1 and maintaining its shape becomes easier, and the workability is further improved. The elastic modulus of the insulating film 3 can be adjusted by changing the material thereof, and when each insulating film 3 is formed of a crosslinked resin, it can also be adjusted by changing the degree of crosslinking.

As a lower limit of the sectional moment per 1 mm width of the pair of insulating films 3, 1.0×10 ⁻¹³ m ⁴ /1 mm is preferable, and 5.0×10 ⁻¹³ m ⁴ /1 mm is more preferable. On the other hand, the upper limit of the sectional moment is preferably 8.0×10 ⁻¹² m ⁴ /1 mm, more preferably 1.0×10 ⁻¹² m ⁴ /1 mm. When the sectional moment is in the above range, the elastic recovery force per 1 mm width of the pair of insulating films 3 can be easily and reliably adjusted to the above range.

The average thickness of each insulating film 3 is preferably 25 μm or more and 200 μm or less. The lower limit of the average thickness is more preferably 40 μm, further preferably 60 μm. On the other hand, the upper limit of the average thickness is more preferably 120 μm, further preferably 80 μm. When the average thickness of each insulating film 3 is less than the above lower limit, the thickness of the insulating film 3 becomes too thin with respect to the thickness of the strip-shaped conductor 2, and as a result, the lead wire 1 for an electric component is attached to the bag body 6. There is a risk of short-circuiting between the strip-shaped conductor 2 and the bag body 6 when heat-sealed. The possibility of this short circuit is particularly remarkable at the edge portions (both ends in the width direction) of the strip-shaped conductor 2. On the other hand, if the average thickness exceeds the upper limit, springback of the electrical component lead wire 1 may not be sufficiently suppressed.

The average thickness and elastic modulus of each insulating film 3 are preferably substantially the same. Specifically, the ratio of the average thickness of the insulating film 3 on the other side to the average thickness of the insulating film 3 on the one side (average thickness of the insulating film 3 on the one side/average thickness of the insulating film 3 on the other side) is 0. It is preferably 95 or more and 1.05 or less. The ratio of the elastic modulus of the insulating film 3 on the other side to the elastic modulus of the insulating film 3 on the one side (the elastic modulus of the insulating film 3 on the one side/the elastic modulus of the insulating film 3 on the other side) is 0.7 or more. It is preferably 0.5 or less.

The lower limit of the ratio of the average thickness of each insulating film 3 to the average thickness of the strip-shaped conductor 2 (average thickness of insulating film/average thickness of strip-shaped conductor) is preferably 0.2, 0.3 Is more preferable, and 0.35 is still more preferable. On the other hand, the upper limit of the above ratio is preferably 1.5, more preferably 1.2, and even more preferably 1.0. When the ratio of the average thickness of each insulating film 3 to the average thickness of the strip conductor 2 is in the above range, the ratio of the elastic recovery force of the pair of insulating films 3 to the shape retention force of the strip conductor 2 is preferable. The range can be adjusted, and as a result, the springback angle can be reduced and the desired bent shape can be maintained.

Ratio of second moment of area per 1 mm width of the pair of insulating films 3 to second moment of area per 1 mm width of the strip-shaped conductor 2 (second moment of area per 1 mm width of the pair of insulating films/width of strip-shaped conductor) As a lower limit of (second moment of area per mm), 1.0 is preferable and 3.0 is more preferable. On the other hand, the upper limit value of the ratio is preferably 4.0×10, more preferably 2.5×10. When the above ratio is in the above range, the ratio of the elastic recovery force of the pair of insulating films 3 to the shape retention force of the strip-shaped conductor 2 can be adjusted to a suitable range, and as a result, the springback angle can be reduced to a desired value. It is possible to maintain the bent shape.

The elastic modulus of each insulating film 3 is preferably 100 MPa or more and 1400 MPa or less. The lower limit of the elastic modulus is more preferably 150 MPa, further preferably 200 MPa. On the other hand, the upper limit of the elastic modulus is more preferably 720 MPa, further preferably 350 MPa. When the elastic modulus of the insulating film 3 is in the above range, the elastic recovery force of the insulating film 3 can be made suitable.

In addition, each of the insulating films 3 has an average thickness of 25 μm or more and 200 μm or less and an elastic modulus of 100 MPa or more and 1400 MPa or less, so that the springback angle after bending the lead wire 1 for an electric component is Can be appropriately small. As a result, the work of bending the electric component lead wire 1 and maintaining its shape becomes easier, and the workability is further improved.

The lower limit of the ratio of the average elastic modulus of the pair of insulating films 3 to the elastic modulus of the strip-shaped conductor 2 (average elastic modulus of the pair of insulating films 3/elastic modulus of the strip-shaped conductor 2) is 1.0×10 ^{−. 3} is preferable, and 2.0×10 ⁻³ is more preferable. On the other hand, the upper limit of the above ratio is preferably 4.0×10 ⁻² , more preferably 1.5×10 ⁻² . When the above ratio is in the above range, the ratio of the elastic recovery force of the pair of insulating films 3 to the shape retention force of the strip-shaped conductor 2 can be adjusted to a suitable range, and as a result, the springback angle can be reduced to a desired value. It is possible to maintain the bent shape.

In the electrical component lead wire 1, the ratio of the elastic recovery force R per 1 mm width of the pair of insulating films 3 to the shape retention force H per 1 mm width of the strip-shaped conductor 2 is 0.15 or less. The upper limit of the ratio is preferably 0.10, more preferably 0.05. The lower limit of the ratio is not particularly limited, but is preferably 0.001 and more preferably 0.002.

It is preferable that the lead wire 1 for electric parts has a bending return angle (springback angle) of 20° or less after being bent by 180°. According to such a lead wire 1 for an electric component, since the bending return angle (spring back angle) after bending by 180° is 20° or less, the bent shape can be more preferably maintained, so that the shape is fixed during bending. Work becomes easier and workability improves. The smaller the bending back angle, the better. It is more preferably 12° or less, further preferably 5° or less, and most preferably 0°.

<Electrical parts>
The electrical component according to the embodiment of the present invention includes an electrical component lead wire 1. Examples of the electric component in which the lead wire 1 for the electric component is used include a non-aqueous electrolyte battery such as a lithium ion battery, a capacitor such as a lithium ion capacitor, and an electric double-layer capacitor (EDLC). Be done. Of course, the electrical component lead wire 1 can be applied to all electrical components that require a lead wire, and the same effect can be obtained when applied to batteries other than the non-aqueous electrolyte battery.

Hereinafter, a non-aqueous electrolyte battery including the electrical component lead wire 1 will be described with reference to the drawings by taking a lithium ion battery as an example.

(Lithium ion battery)
The lithium ion battery 4 shown in FIGS. 1 and 2 has a bag body 6 in which a battery element holding a non-aqueous electrolyte is enclosed. The battery element holds a non-aqueous electrolyte solution with a separator (not shown) interposed between the positive electrode 5A and the negative electrode 5B. As the non-aqueous electrolyte, for example, a solution obtained by dissolving a lithium compound (LiClO ₄ , LiBF _4, etc.) in an organic solvent such as propylene carbonate, γ-butyrolactone or the like is used.

The electrical component lead wire 1 is fixed to the bag body 6 with an insulating film 3. In the lead wire 1 for electric parts, one end 2A and the other end 2B of the strip conductor 2 are exposed from the insulating film 3, and the exposed one end 2A of the strip conductor 2 is the positive electrode of the battery element. 5A or the negative electrode 5B is electrically connected, and the exposed other end 2B of the strip-shaped conductor 2 projects from the bag body 6.

Since such a lithium-ion battery 4 is provided with the electric component lead wire 1, the work for bending the electric component lead wire 1 and maintaining the shape thereof can be simplified, thereby improving the work efficiency.

Even when the electric component lead wire 1 is applied to an electric component other than the lithium ion battery 4, the work efficiency can be improved by simplifying the work for maintaining the bent shape.

Next, the present invention will be specifically described with reference to experimental examples. However, the present invention is not limited to the following experimental examples, and may be appropriately modified and implemented within a range compatible with the gist of the present invention. And all of them are included in the technical scope of the present invention.

In this experimental example, the springback angle of the lead wire was evaluated.

<Lead wire>
The lead wire was formed by covering the central portion of the strip-shaped conductor with a pair of insulating films so that both ends of the strip-shaped conductor were exposed. As shown in FIGS. 4A and 4B, the strip-shaped conductor 7 has a length L _m of 80 mm, a width W _m of 5 mm, and an elastic modulus and an average thickness T _m shown in Table 1 below. I was there. As the insulating film 8, those having a length L _i of 6 mm, a width W _i of 7 mm, an elastic modulus and an average thickness T _i shown in Table 1 below were used. The two insulating films 8 were the same. The total average thickness of the strip-shaped conductor 7 and the pair of insulating films 8 was defined as the average thickness T of the lead wire.

<Second moment of area>
The second moment of area [m ⁴ /1 mm] per 1 mm width of the strip-shaped conductor 7 is substituted by 1/12×W _m [m]×(T _m [m]) ³ /W _m [mm]. I asked. The second moment of area [m ⁴ /1 mm] of the pair of insulating films 8 is 1/12×W _i [m]×{(T[m]) ³ −(T _m [m]) ³ }/W _i [ mm] was substituted for each numerical value.

<Evaluation of springback angle>
As for the spring back angle, as shown in FIG. 5A, first, the end surface of the plate material X having a thickness of 0.5 mm is brought into contact with the vicinity of the center in the length direction of the insulating film 8 on one side of the lead wire to sandwich the plate material X. After slowly bending the lead wire by 180° as described above, a load F was applied by placing a weight of 200 g on the insulating film 8 on the other side, and this state was maintained for 10 seconds. Next, as shown in FIG. 5B, the evaluation was performed by measuring the springback angle θ [deg] (angle formed by the lead wire) when the load was removed and left for 5 seconds or more. The measurement results of the springback angle are shown in Table 1 below. Further, FIG. 6 shows the relationship between the springback angle θ and the ratio (R/H) of the elastic recovery force R per 1 mm width of the pair of insulating films to the shape retention force H per 1 mm width of the strip-shaped conductor. .. The elastic recovery force R and the shape retention force H of the lead wire were calculated based on the above mathematical expressions (1) and (2), respectively.

As shown in Table 1 and FIG. 6, the average thickness T1 of the strip-shaped conductor was changed, and the other conditions were the same as group A (manufacturing examples 1 to 4), group B (manufacturing examples 5 to 8), and group. In C (Manufacturing Examples 9 to 12), in all groups, the springback angle increased as the average thickness T1 of the strip conductors increased, that is, the ratio (R/H) of the elastic recovery force R to the shape retention force H decreased. θ also became smaller. In addition, although the groups A to C are different from each other in the thickness T2 of the insulating film, when these groups A to C are compared, the thickness T2 of the insulating film is increased, that is, the elastic retention force R with respect to the shape retention force H. The springback angle θ also increased as the ratio (R/H) increased. From these results, the average thickness of the strip-shaped conductor of the lead wire and the average thickness of the insulating film are adjusted, and the ratio (R/H) of the elastic recovery force R to the shape retention force H is set to 0.15 or less. It is judged that it is possible to maintain a good bent shape with a back angle of 20° or less.

In Group D (Production Examples 13 to 14) and Group E (Production Examples 15 to 16) in which the elastic modulus of the insulating film was changed and the other conditions were the same, the elastic modulus of the insulating film was As the ratio (R/H) of the elastic recovery force R to the shape holding force H increases, the springback angle θ also increases. From this result, by adjusting the elastic modulus of the insulating film of the lead wire and setting the ratio (R/H) of the elastic recovery force R to the shape holding force H to 0.15 or less, the spring back angle of 20° or less was excellent. It is judged that the bent shape can be maintained.

In Group F (Production Examples 17 to 20) in which the thickness of the strip-shaped conductor and the insulating film were constant and the elastic modulus was changed, the elastic modulus of the strip-shaped conductor was increased, the elastic modulus of the insulating film was reduced, or a combination thereof was used. When the ratio (R/H) of the elastic recovery force R to the shape retention force H was reduced, the springback angle θ was reduced accordingly. From this result, by adjusting the elastic modulus of the insulating film of the lead wire and setting the ratio (R/H) of the elastic recovery force R to the shape holding force H to 0.15 or less, the spring back angle of 20° or less was excellent. It is judged that the bent shape can be maintained.

Further, as shown in FIG. 6, the ratio (R/H) of the elastic recovery force R to the shape holding force H and the springback angle show a high correlation, and in particular, the ratio (R/H) is small (for example, 0. In the production examples, higher correlation was shown. Therefore, it can be confirmed that adjusting the ratio (R/H) is very effective in reducing the springback angle.

According to the above invention, it is possible to provide a lead wire for an electric component, which is less likely to cause springback when used in bending, and which can maintain a preferable bent shape, and an electric component which is excellent in work efficiency.

1,11 Lead wire for electric parts 2,7,12 Strip conductor 2A One end 2B The other end 3,8,13 Insulation film 4 Lithium ion battery 5A Positive electrode 5B Negative electrode 6 Bag M Central surface of bending deformation

Claims (8)

A lead wire for an electric component, comprising a strip conductor and a pair of insulating films covering both surfaces of the strip conductor,
The elastic modulus of the strip conductor is D _m [Pa], the second moment of area per 1 mm width is I _m [m ⁴ /1 mm], and the average elastic modulus of the pair of insulating films is D _i [Pa], When the second moment of area per 1 mm in width is I _i [m ⁴ /1 mm], the shape-retaining force H [N·m ² /1 mm per 1 mm in width of the strip-shaped conductor represented by the following mathematical formula (1). ] The ratio (R/H) of elastic recovery force R [N·m ² /1 mm] per 1 mm width of the insulating film represented by the following mathematical formula (2) is 0.15 or less.
H=D _m ×I _m (1)
R=D _i ×I _i (2) The lead wire for an electric component according to claim 1, wherein a bending return angle after bending by 180° is 20° or less. The lead for electrical parts according to claim 1 or 2, wherein the elastic recovery force R is 3.0 × 10 ^-5 N·m ² /1 mm or more and 6.0 × 10 ^-3 N·m ² /1 mm or less. line. The shape retention force H is 3.0×10 ⁻⁴ N·m ² /1 mm or more and 6.0×10 ⁻² N·m ² /1 mm or less, according to claim 1, claim 2 or claim 3. Lead wire for electrical parts. The strip-shaped conductor has an average thickness of 30 μm or more and 200 μm or less,
The lead wire for an electric component according to any one of claims 1 to 4, wherein an elastic modulus of the strip conductor is 50 GPa or more and 300 GPa or less. Each of the insulating films has an average thickness of 25 μm or more and 200 μm or less,
The lead wire for an electric component according to any one of claims 1 to 5, wherein each of the insulating films has an elastic modulus of 100 MPa or more and 1400 MPa or less. An electric component comprising the lead wire for an electric component according to claim 1. The electric component according to claim 7, which is a non-aqueous electrolyte battery.

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