JP4677708B2 - Lead, power storage device, and lead manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrolyte battery used as a power source for electronic equipment and the like, a power storage device such as a capacitor, a lead conductor used therefor, a lead, and a method for manufacturing the same, and more specifically, a positive electrode, a negative electrode, an electrolyte medium, and the like. The present invention relates to a power storage device including a bag body to be sealed, a lead conductor used in the power storage device, a lead, and a method of manufacturing the lead conductor.
[0002]
[Prior art]
In accordance with the demand for downsizing of electronic devices, there is an increasing demand for downsizing and weight reduction of batteries used as power sources. On the other hand, higher energy density and higher energy efficiency for batteries are also required. In order to satisfy such a demand, an electrolyte battery (for example, a non-aqueous electrolyte battery such as a Li ion battery or a lithium polymer battery) in which a positive electrode, a negative electrode, an electrolytic solution, etc. are sealed inside a bag made mainly of a synthetic resin or the like is used. Expectations are rising.
[0003]
In such an electrolyte battery, in general, a lead conductor extends from the inside of the bag body to the outside in order to extract current from the positive electrode and the negative electrode to the outside. The lead conductors for the positive electrode and the negative electrode are sealed by heat-sealing with the insulator on the inner surface of the bag body.
[0004]
In the conventional electrolyte battery, the insulator may be peeled off from the lead conductor while being repeatedly charged and discharged over a long period of time. For example, when the lead conductor / insulator combination is a metal / ionomer, metal / modified polypropylene, or the like, and the electrolyte contains a chlorine or fluorine-containing lithium salt, the lead conductor / insulation is performed at a high temperature of 60 ° C. or higher. The adhesive force at the interface of the body is reduced, and the lead conductor and the insulator are easily separated at the interface. And it has become clear that the penetration of moisture, oxygen, etc. from the outside into the battery through this peeling part is promoted and the battery performance is lowered.
[0005]
And in order to prevent the peeling of the insulator from such a lead conductor, for example, a method of performing alumite treatment or boehmite treatment on the lead conductor (see Patent Document 1), dry blast treatment, wet blast treatment on the lead conductor, A method of performing mechanical rough surface processing such as embossing processing (see Patent Document 2) is known.
[0006]
[Patent Document 1]
JP 2000-149913 A
[Patent Document 2]
JP 2000-149914 A
[0007]
[Problems to be solved by the invention]
However, in the method of performing alumite treatment or boehmite treatment, it is necessary to perform the treatment only on the portion of the lead conductor that is covered with the insulator. It becomes. On the other hand, the mechanical surface roughening method such as the blast method is not sufficient in preventing the peeling of the insulator from the lead conductor.
[0008]
The present invention has been made in view of the above circumstances, can reduce the cost, and can sufficiently prevent the peeling of the insulator from the lead conductor over a long period of time. Ru Lead, power storage device using the same , And it aims at providing the manufacturing method of a lead.
[0009]
[Means for Solving the Problems]
The inventors of the present invention have studied the problems of the above prior art. As a result, it has been found that movement of substances such as moisture from the outside to the inside of the bag body and movement of electrolytes such as fluorine compounds from the inside of the bag body to the outside occur between the lead conductor and the insulator. And it discovered that a lead conductor was corroded by these substances moving between a lead conductor and an insulator, and an insulator became easy to peel from a lead conductor. In particular, in a non-aqueous electrolyte battery using a non-aqueous electrolyte medium, moisture and a fluorine compound in the non-aqueous electrolyte react with each other to generate a corrosive substance such as hydrofluoric acid, and the tendency of such corrosion is remarkable.
[0011]
Therefore, The lead according to the present invention encloses an electrolyte medium, a positive electrode, and a negative electrode Bag (second bag) Lead conductors projecting from the inside to the outside, and covering the lead conductors bag Inside End of An insulator fused to the lead, The lead conductor is a plate, Lead conductor Both main faces In the surface of the portion covered with the insulator in FIG. 1, there is a groove extending in the direction intersecting the direction in which the lead conductor protrudes. Respectively Is formed.
[0012]
The power storage device according to the present invention is Bag (second bag) When, An insulator fused to the inner edge of the bag and , bag Electrolyte medium, positive and negative electrodes, and insulator Covered Is bag Protruding from inside to outside Is Lead conductor for positive electrode and insulator Covered Is bag In a power storage device comprising a negative electrode lead conductor protruding from the inside to the outside, At least one of the lead conductor for positive electrode and the lead conductor for negative electrode is a plate-like body, At least one of a positive lead conductor and a negative lead conductor Both main faces In the portion fused with the insulator, a groove extending in a direction intersecting the direction in which the lead conductor protrudes is formed. Respectively Is formed.
[0013]
According to these inventions, the lead conductor is formed on the portion of the lead conductor covered with the insulator. bag A groove extending in a direction intersecting with the direction extending from the inside to the outside of the substrate is formed. This sufficiently suppresses movement of substances such as moisture and electrolyte medium along the direction in which the lead conductor protrudes between the lead conductor and the insulator. For this reason, corrosion of the lead conductor between the lead conductor and the insulator is sufficiently suppressed. Therefore, peeling of the insulator from the lead conductor is sufficiently prevented over a long period of time. In addition, since such a groove can be easily formed by pressing or the like, it can be realized at a low cost.
[0014]
here, On both sides, It is preferable that a plurality of grooves are formed apart from each other, thereby further restricting the movement of the substance between the lead conductor and the insulator.
[0015]
The lead conductor is a plate-like body. R , Forming grooves on both sides of the plate Because As a result, the peeling of the insulator can be effectively suppressed.
[0016]
The insulator preferably includes at least two layers having different deformation amounts when heated, whereby the lead has a metal layer. bag The possibility of a short circuit between the lead conductor and the metal layer can be reduced.
[0017]
In addition, one of the two layers of the insulator is preferably a layer crosslinked by electron beam irradiation, thereby suitably forming a layer with less deformation than the other layer. it can.
[0018]
Alternatively, one of the two layers of the insulator may have a higher melting point than that of the other layer, and accordingly, a layer having a smaller amount of deformation than the other layer is preferably used. Can be formed.
[0020]
In the lead conductor manufacturing method according to the present invention, the electrolyte medium, the positive electrode, and the negative electrode are enclosed. Bag (second bag) Lead conductors projecting from the inside to the outside, and covering the lead conductors bag An insulator fused to the inner surface of the lead, comprising: It is a plate-like body Lead conductor Both lords A groove extending in the direction intersecting the direction in which the lead conductor protrudes is formed on the surface. Respectively And a step of covering the portion of the lead conductor where the groove is formed with an insulator.
[0021]
According to such a manufacturing method, as described above. Ki A lead can be suitably manufactured.
[0022]
Here, it is preferable to form a groove by pressing. According to this, since a groove can be easily formed, mass production can be performed at low cost.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or equivalent components are denoted by the same reference numerals.
[0024]
FIG. 1 is a perspective view showing a preferred embodiment of the power storage device of the present invention, and shows a nonaqueous electrolyte battery as the power storage device. The non-aqueous electrolyte battery 10 of the present embodiment has a thin wall shape as shown in FIG. 1, and the non-aqueous electrolyte battery 10 has an electrolyte (for example, a lithium fluoride compound) in a non-aqueous solvent (for example, an organic solvent). A single electrochemical cell containing a dissolved non-aqueous electrolyte (electrolyte medium) is formed by enclosing it in an encapsulating bag 14 in which a peripherally heat-sealed portion 12 is formed. Yes. In the non-aqueous electrolyte battery 10, one end of the positive electrode lead 18a and the negative electrode lead 18b extends upward from the upper part of the encapsulating bag 14 to enable electrical connection with the outside. Each of the positive electrode lead 18a and the negative electrode lead 18b has a lead conductor 19 extending from the inside to the outside of the encapsulating bag 14, and an outer periphery of each of them is covered with an insulator 21. Here, the enclosure bag 14 and the insulator 21 constitute an enclosure bag 114 with an insulator, and the enclosure bag 114 with an insulator corresponds to the first bag body. The encapsulating bag 14 corresponds to the second bag body.
[0025]
FIG. 2 is a view taken along the line II-II of the nonaqueous electrolyte battery 10 of FIG. As shown in FIG. 2, from the viewpoint of suppressing the penetration of the non-aqueous electrolyte solution 20, the encapsulating bag 14 is formed by sandwiching a metal foil or metal layer 22 made of aluminum, for example, with layers 24 and 28 made of plastic layers. It consists of a formed multilayer film.
[0026]
More specifically, the encapsulating bag 14 is formed by heat-sealing the peripheral portion of the innermost layer 24 of the multilayer film in contact with the non-aqueous electrolyte 20. Here, the innermost layer 24 is made of, for example, maleic acid-modified polyolefin (for example, maleic acid-modified polyolefin) from the viewpoint of preventing leakage of the non-aqueous electrolyte 20 in the heat seal portion 12 formed at the peripheral edge of the inner layer 24. The outermost layer 28 of the encapsulating bag 14 is provided to protect the metal layer 22 from damage, and is made of, for example, PET (polyethylene terephthalate).
[0027]
Moreover, as the non-aqueous electrolyte solution 20 accommodated in the enclosing bag 14, for example, an organic solvent such as propylene carbonate and γ-butyrolactone, LiBF _Four , LiPF ₆ , LiAsF ₆ A solution in which a solute made of a lithium fluoride compound is dissolved is used. Further, a positive electrode plate (positive electrode) 30 and a negative electrode plate (negative electrode) 32 that are immersed in the non-aqueous electrolyte 20 are enclosed in the encapsulating bag 14, and the positive electrode plate 30 and the negative electrode plate 32 are called current collectors. It consists of a metal substrate (not shown) of metal foil or expanded metal and an active material layer (not shown) formed on the metal substrate. Further, a separator 34 for preventing diffusion of the nonaqueous electrolytic solution 20 is disposed between the positive electrode plate 30 and the negative electrode plate 32.
[0028]
Further, the metal base material of the positive electrode plate 30 is connected to one end of the lead conductor 19 of the positive electrode lead 18 a through the conductive wire 36, and the other end of the lead conductor 19 extends to the outside of the encapsulating bag 14. The metal base material of the negative electrode plate 32 is also connected to one end of the lead conductor 19 of the negative electrode lead 18 b via a conductive wire 38, and the other end of the lead conductor 19 extends to the outside of the encapsulating bag 14. Further, a part of the lead conductor 19 of the positive electrode lead 18 a and a part of the lead conductor 19 of the negative electrode lead 18 b are respectively covered by welding with the insulator 21. The positive electrode lead 18 a and the negative electrode lead 18 b are attached to the encapsulating bag 14 by thermally bonding the respective insulators 21 to the innermost layer 24 of the encapsulating bag 14.
[0029]
Here, the positive electrode lead 18a and the negative electrode lead 18b will be described in detail.
[0030]
FIG. 3 is a partially broken perspective view of the positive lead 18a and the negative lead 18b. The positive electrode lead 18a and the negative electrode lead 18b according to the present embodiment surround a lead conductor 19 that is a rectangular plate-shaped electric conductor having a predetermined length and an outer periphery of a substantially central portion in the length direction of the lead conductor 19. And an insulator 21 which is fused and covered. Here, the length direction of the lead conductor 19 corresponds to the direction in which the lead conductor 19 extends from the inside of the encapsulating bag 14 to the outside in the nonaqueous electrolyte battery 10 described above.
[0031]
And in the lead 18a for positive electrodes and the lead 18b for negative electrodes which concern on this embodiment, on the surface of the part which the insulator 21 in the lead conductor 19 coat | covers, the some extended in the direction orthogonal to the length direction of this lead conductor 19 A groove 120 is formed.
[0032]
The grooves 120 are formed apart from each other in the length direction of the lead conductor 19. The depth of the groove 120 is preferably 1 to 20% and more preferably 5 to 15% with respect to the thickness of the conductor. The opening width of the groove 120 is preferably 2 to 500 μm, and more preferably 5 to 50 μm. Furthermore, the interval between the grooves 120 is, for example, about 0.1 to 1.0 mm.
[0033]
Further, the groove 120 is formed in each of the main surfaces 19 a and 19 b of the lead conductor 19. And the groove | channel 120 is continuously formed ranging from the one edge of each main surface 19a to the other edge. Moreover, the cross-sectional shape of the groove | channel 120 is a rectangle, for example.
[0034]
As the material of the lead conductor 19 for the positive electrode lead 18a, for example, aluminum or stainless steel can be used.
[0035]
For example, when aluminum is used, the purity of aluminum is preferably 97% or more. If the purity of aluminum is less than 97%, impurities may adversely affect the performance of the nonaqueous electrolyte battery 10.
[0036]
Further, the material of the lead conductor 19 of the negative electrode lead 18b may be a material that does not easily form a lithium alloy or the like and is difficult to dissolve during overdischarge in which a deposit such as lithium is generated during overcharging or the potential difference is large. , Copper, stainless steel, or an alloy thereof can be used. Examples of these alloys include nickel-plated copper.
[0037]
The insulator 21 has a thermoplastic layer 23 that is thermally fused to the outer periphery of the lead conductor 19. The thermoplastic layer 23 covers and seals the outer periphery of the lead conductor 19 so as to bite into the groove 120.
[0038]
The thermoplastic layer 23 can use, for example, a thermoplastic polyolefin resin. As such a thermoplastic polyolefin resin, those that can be bonded to the lead conductor 19 are used, and among these, polyethylene and acid-modified polyethylene are melted by heating and are more easily fused to the lead conductor 19. , Reactive resins such as polypropylene, ethylene vinyl acetate copolymer, acid-modified polypropylene (for example, maleic anhydride-modified polypropylene), ionomer, or mixtures thereof are preferable. Here, when polypropylene having excellent heat resistance is used as the material constituting the innermost layer 24 of the encapsulating bag 14, it is preferable to use polypropylene or acid-modified polypropylene among the thermoplastic polyolefin resins. In this case, compared with the case where polyethylene or ethylene vinyl acetate copolymer is used as the thermoplastic polyolefin resin, the adhesion between the insulator 21 and the innermost layer 24 of the encapsulating bag 14 is improved, and the nonaqueous electrolyte battery 10 is high. Heat resistance can be imparted. As the above ionomer, a homopolymer such as polyethylene or polypropylene, or a copolymer of ethylene and methacrylic acid or the like crosslinked with Na, Mg, K or the like is used.
[0039]
The insulator 21 includes a cross-linked layer 25 outside the thermoplastic layer 23. As the crosslinked layer 25, a crosslinked polyolefin resin can be used. The polyolefin resin is not particularly limited as long as it can be heat-sealed with the innermost layer 24 of the encapsulating bag 14, but the same resin as the above-described thermoplastic polyolefin resin is preferably used. This is because when a resin different from the above-described thermoplastic polyolefin resin is used, the adhesive force between the thermoplastic layer 23 and the crosslinked layer 25 tends to decrease.
[0040]
Here, when polypropylene having excellent heat resistance is used as the material constituting the innermost layer 24 of the encapsulating bag 14, it is preferable to use polypropylene or acid-modified polypropylene as the polyolefin resin. In this case, compared to the case where polyethylene or ethylene vinyl acetate copolymer is used as the polyolefin resin, the adhesiveness between the insulator 21 and the innermost layer 24 of the encapsulating bag 14 and the heat resistance of the nonaqueous electrolyte battery 10 are further increased. Will improve.
[0041]
As a method for crosslinking the polyolefin resin, crosslinking by irradiation with ionizing radiation such as electron beam or gamma ray, chemical crosslinking with peroxide, silane crosslinking, or the like is used. When the polyolefin resin is crosslinked by ionizing radiation, a crosslinking aid is added to the polyolefin resin as necessary. Examples of the crosslinking aid include trimethylolpropane methacrylate, pentaerythritol triacrylate, ethyne glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, and the like.
[0042]
The cross-linked polyolefin resin is excellent in heat-resistant deformation even when heated above its melting point, and when the insulator 21 of the leads 18a and 18b is heat-sealed to the inner surface of the encapsulating bag 14, the lead conductor 19 is encapsulated. It is possible to sufficiently prevent a short circuit between the bag 14 and the metal layer 22.
[0043]
Moreover, in crosslinked polyolefin resin, it is preferable that the gel fraction is 20%-90%. The gel fraction is an index indicating the degree of crosslinking and refers to the ratio of gel (insoluble polymer chain) in the crosslinked polyolefin resin that has become insoluble in a solvent such as xylene. If the gel fraction is less than 20%, the degree of crosslinking is insufficient, and the metal layer 22 of the encapsulating bag 14 and the lead conductor 19 are short-circuited when the inner surface of the encapsulating bag 14 and the crosslinked layer 25 are heat-sealed. It tends to be easy. On the other hand, when the gel fraction exceeds 90%, the degree of cross-linking is too large, the adhesion between the encapsulating bag 14 and the cross-linking layer 25 is poor, and the nonaqueous electrolyte solution 20 tends to leak out.
[0044]
The insulator 21 covered with the lead conductor 19 of the negative electrode lead 18b also includes a thermoplastic layer 23 and a crosslinked layer 25. The thermoplastic polyolefin resin constituting the thermoplastic layer 23 and the crosslinked layer constituting the crosslinked layer 25 are also included. As the polyolefin resin, a thermoplastic polyolefin resin and a crosslinked polyolefin resin used in the lead conductor 19 of the positive electrode lead 18a can be used, respectively.
[0045]
According to the nonaqueous electrolyte battery 10, the groove 120 extending in the direction orthogonal to the direction in which the lead conductor 19 extends from the inside to the outside is formed in the portion of the lead conductor 19 covered with the insulator 21. For this reason, movement of substances such as moisture and fluoride along the direction in which the lead conductor 19 extends between the lead conductor 19 and the insulator 21 is sufficiently suppressed. Thereby, corrosion of the lead conductor 19 between the lead conductor 19 and the insulator 21 is sufficiently prevented. Therefore, peeling of the insulator 21 from the lead conductor 19 can be sufficiently prevented over a long period of time. In particular, when the electrolyte has a fluoride, the production of corrosive substances such as hydrofluoric acid produced by the reaction between the fluoride and water is reduced, which is highly effective.
[0046]
In addition, since the thermoplastic layer 23 of the insulator 21 bites into the groove 120, the insulator 21 is hardly peeled off from the lead conductor by the anchor effect.
[0047]
Therefore, the performance deterioration of the battery 10 due to the leakage of the non-aqueous electrolyte is sufficiently prevented, and the external device is sufficiently prevented from being corroded by the hydrofluoric acid leaking to the outside of the enclosing bag 14.
[0048]
Here, the cross-sectional shape of the groove 120 is not particularly limited, and other than a rectangular cross-section, for example, application of a groove having a cross-sectional shape such as a V shape or a U shape may be considered.
[0049]
Further, the groove 120 may be formed on the side surfaces 19 c and 19 d of the lead conductor 19.
Further, the groove 120 does not necessarily extend from one edge of the lead conductor 19 to the other edge.
[0050]
Next, a method for manufacturing the battery 10 will be described. First, the first manufacturing method will be described. Here, first, a method of manufacturing the lead conductor 19 and the positive electrode lead 18a will be described.
[0051]
First, as shown in FIG. 4A, a rectangular flat aluminum plate having a predetermined length is prepared as the lead conductor 19 of the positive electrode lead 18a. Then, grooves 120 extending in the width direction are formed in part of the front and back surfaces of the lead conductor 19 as shown in FIG. The groove 120 is formed by pressing the lead conductor 19 with a mold on the surface of which a protrusion 205 having a direction perpendicular to the length direction of the lead conductor 19 is formed.
[0052]
On the other hand, as shown in FIG. 5 (a), for example, a thermoplastic thermoplastic film 23A made of a polyolefin resin such as maleic anhydride-modified low density polyethylene and a crosslinked resin made of a polyolefin resin such as low density polyethylene can be formed. Each thermoplastic film 25A is produced with a T-die or an inflation extruder. Then, as shown in FIG. 5B, the thermoplastic film 25A is subjected to a crosslinking treatment to produce a crosslinked thermoplastic film 25B. As a method of crosslinking treatment, irradiation crosslinking by ionizing radiation such as γ rays or electron beams, chemical crosslinking by peroxide, etc., silane crosslinking, etc. are used. From the viewpoint of improving productivity, crosslinking is performed in a short time. Irradiation crosslinking capable of is most preferred. Then, the crosslinked thermoplastic film 25B thus obtained and the above-described thermoplastic film 23A are bonded together by thermal lamination as shown in FIG. 5 (c), and the thermoplastic layer 23 and the crosslinked layer 25 are bonded together. Thus, an insulator 21 composed of two layers is obtained.
[0053]
Next, two insulators 21 thus obtained are prepared, and the lead conductors 19 are sandwiched with the respective thermoplastic layers 23 facing the lead conductors 19 as shown in FIG. Thereafter, the insulator 21 is heated to heat-seal the thermoplastic layer 23 of the insulator 21 and the lead conductor 19. Thus, a positive electrode lead 18a as shown in FIG. 7 is obtained.
[0054]
The negative electrode lead 18b is also produced by the same method as described above. However, the lead conductor 19 of the negative electrode lead 18b may be a material used for the lead conductor 19 of the positive electrode lead 18a, but is made of an alloy such as copper, nickel, stainless steel, or nickel-plated copper. Is preferably used.
[0055]
The manufacturing method of the leads 18a and 18b is not limited to the method described above. For example, after preparing a one-layer thermoplastic film made of a polyolefin resin and thermally fusing the thermoplastic film to the lead conductor 19, the transmission distance is smaller than the thickness of the film from the outside of the thermoplastic film. The leads 18a and 18b can also be obtained by irradiating the controlled electron beam. In this case, the portion of the thermoplastic film that has been exposed to the electron beam becomes the crosslinked layer 25, and the portion that has not received the electron beam becomes the thermoplastic layer 23.
[0056]
According to such a manufacturing method, the lead conductor 19 and the leads 18a and 18a formed with the grooves 120 as described above can be suitably formed. Furthermore, since the groove 120 is formed by pressing, it is suitable for mass production and can be produced at low cost.
[0057]
Next, an example of a method for attaching the positive electrode lead 18a and the negative electrode lead 18b to the encapsulating bag 14 will be described.
[0058]
The encapsulating bag 14 to which the positive lead 18a and the negative lead 18b are attached is manufactured as follows. That is, first, a pair of rectangular multilayer films including a layer made of maleic acid-modified polyolefin on the surface and a metal foil or metal layer inside is prepared. Next, these multilayer films are overlapped so that the layers of the maleic acid-modified polyolefin face each other, and the two sides around the rectangle are heat-sealed by a desired seal width using a sealing machine under predetermined heating conditions. Thus, an encapsulating bag 14 having openings on two sides (the upper side in the drawing and the direction perpendicular to the paper surface) is obtained (see FIG. 8A).
[0059]
Part of the positive electrode lead 18 a and the negative electrode lead 18 b is accommodated in the encapsulating bag 14 through the opening at the top of the encapsulating bag 14. At this time, the insulator 21 of the positive electrode lead 18 a and the insulator 21 of the negative electrode lead 18 b are accommodated so as to be disposed between the innermost layers 24 of the enclosing bag 14. Then, after connecting the lead conductors 19 and 19 to the positive electrode plate 30 and the negative electrode plate 32, the insulator 21 is sandwiched between the opening end portions of the encapsulating bag 14, and the cross-linking layer 25 of the insulator 21 is connected with a sealing machine. The innermost layer 24 of the encapsulating bag 14 is heat-sealed (see FIG. 8B). Here, the insulator 21 covering the groove 120 is fused to the innermost layer 24 of the encapsulating bag 14 with one end in the length direction of the lead conductor 19 protruding from the inside of the encapsulating bag 14 to the outside.
[0060]
At this time, the insulator 21 includes the cross-linked layer 25, the melting point of the cross-linked layer 25 in the insulator 21 is lower than that of the thermoplastic layer 23, and the cross-linked layer 25 is less likely to melt than the thermoplastic layer 23. Therefore, a short circuit between the lead conductor 19 and the metal layer 22 of the encapsulating bag 14 is sufficiently prevented by heating at the time of heat fusion.
[0061]
Subsequently, the non-aqueous electrolyte 20 is introduced into the enclosing bag 14 from the remaining opening, and the inside is decompressed to heat-seal the opening, whereby a non-aqueous electrolyte battery as shown in FIG. 1 is obtained.
[0062]
Next, another battery manufacturing method according to this embodiment will be described. In the present embodiment, the difference from the manufacturing method described above is that the insulator 21 is fused to the inner surface of the encapsulating bag 14 in advance to form an encapsulating bag (first bag) 114 with an insulator (FIG. 9 ( The lead conductor 19 in the state of FIG. 4B in which the groove 120 is formed but the insulator 21 is not fused is replaced with the encapsulating bag 114 with an insulator as shown in FIG. 9A. It is the point which inserts in and fuse | fuses with the thermoplastic layer 23 of the insulator 21 in the enclosure bag 114 with an insulator (refer FIG.9 (b)). Here, in a state where one end of the lead conductor 19 in the length direction protrudes from the inside of the encapsulating bag 14 to the outside, the portion where the groove 120 is formed in the lead conductor 19 is fused to the innermost layer 24 of the encapsulating bag 14. Is done. This also makes it possible to manufacture the same battery as described above, and has the same effects.
[0063]
Here, the present invention is not limited to the above embodiment. For example, in the above embodiment, the non-aqueous electrolyte battery 10 is used as the power storage device, but an aqueous electrolyte battery in which an electrolyte is dissolved in an aqueous solution may be used. Further, a capacitor may be used instead of the electrolyte battery. In this case, it is necessary to use solid activated carbon in each of the positive electrode plate 30 and the negative electrode plate 32. When a capacitor is used, it is preferable to use aluminum as the lead conductor 19 of the negative electrode lead 18b.
[0064]
Hereinafter, the contents of the present invention will be described more specifically with reference to examples.
Example 1
First, a copper plate having a thickness of 0.1 mm, a width of 5 mm, and a length of 50 mm was prepared as the lead conductor 19. Then, grooves 120 were formed on the front and back surfaces of the lead conductor 19 by pressing. Here, the depth of the groove 120 is 10 μm, the cross-sectional shape is substantially rectangular, the interval between the grooves 120 is 0.5 mm, and the groove 120 is formed to extend from one edge of the surface of the lead conductor 19 to the other edge. Ten grooves 120 were formed.
[0065]
On the other hand, a maleic anhydride-modified low-density polyethylene film having a thickness of 50 μm (density: 0.92 g / cm ^Three , Melt flow rate (MFR): 1.0 g / 10 min, melting point: 123 ° C., and a low-density polyethylene film having a thickness of 50 μm (density: 0.92 g / cm) ^Three , MFR: 1.0 g / 10 min, melting point: 123 ° C.), and for the low density polyethylene film, an electron beam irradiation device is used so that the absorbed dose of an electron beam with an acceleration voltage of 200 kV is 30 kGy. Were cross-linked by irradiation. The MFR of the maleic anhydride-modified low density polyethylene film and the low density polyethylene film was measured according to JISK-6760 (test temperature: 190 ° C., load: 21.17 N).
[0066]
Then, the maleic anhydride-modified low density polyethylene film and the low density polyethylene film were bonded together by heat laminating at 150 ° C. Next, the laminate film was cut to obtain two 7 mm × 15 mm square insulators 21.
[0067]
Thereafter, the two insulators 21 are overlapped so as to oppose each other via the lead conductor 19, and in this state, the insulator 21 is subjected to a heat press at 150 ° C. for 10 seconds and the groove 120 is formed by the lead conductor 19. After that, it was cut so that the insulation length in the conductor width direction was 9 mm to form the negative electrode lead 18b.
[0068]
The negative electrode lead 18b thus obtained was mixed with ethylene carbonate (EC): diethyl carbonate (DEC): dimethyl carbonate (DMC) = 1: 1: 1 and a lithium fluoride compound. The time until it was immersed in the electrolyte solution contained and peeled was observed. As a result, peeling of the insulator 21 from the lead conductor 19 was not observed even after 168 hours had passed.
[0069]
(Comparative Example 1)
A negative electrode lead was obtained in the same manner as in Example 1 except that the groove 120 was not formed in the lead conductor 19. Then, as in Example 1, the negative electrode lead was immersed in the electrolytic solution. As a result, the insulator was peeled from the lead conductor in 3h.
[0070]
【The invention's effect】
As described above, according to the present invention, it is possible to sufficiently prevent the insulator from being peeled off from the lead conductor for a long period of time at a low cost. Accordingly, leakage of the electrolytic solution is sufficiently suppressed, and deterioration of battery performance and corrosion of external equipment can be sufficiently reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a power storage device of the present invention.
FIG. 2 is a view taken along the line II-II in FIG. 1;
FIG. 3 is a perspective view showing an embodiment of the lead of the present invention.
4A is a perspective view for explaining a lead manufacturing method, and FIG. 4B is a perspective view following FIG. 4A for explaining a lead manufacturing method.
FIG. 5A, FIG. 5B, and FIG. 5C are schematic views subsequent to FIG. 4B for explaining a lead manufacturing method.
FIG. 6 is a perspective view subsequent to FIG. 5 for explaining the lead manufacturing method;
7 is a perspective view subsequent to FIG. 6 for explaining the lead manufacturing method; FIG.
8A is a schematic diagram for explaining a method for manufacturing a nonaqueous electrolyte battery, and FIG. 8B is a schematic diagram for explaining a method for manufacturing a nonaqueous electrolyte battery following FIG. 8A. It is.
9A is a schematic diagram illustrating another method for manufacturing a non-aqueous electrolyte battery, and FIG. 9B illustrates another method for manufacturing the non-aqueous electrolyte battery subsequent to FIG. 9A. It is a schematic diagram to explain.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Nonaqueous electrolyte battery, 14 ... Encapsulation bag (second bag body), 18a ... Lead for positive electrode, 18b ... Lead for negative electrode, 19 ... Lead conductor, 20 ... Nonaqueous electrolyte (electrolyte medium), 21 ... Insulator 22 ... Metal layer, 23 ... Thermoplastic layer, 25 ... Cross-linked layer, 30 ... Positive electrode plate (positive electrode), 32 ... Negative electrode plate (negative electrode), 114 ... Encapsulated bag with insulator (first bag body), 120 ... groove.

Claims (7)

A lead comprising an electrolyte medium, a positive electrode, and a lead conductor protruding from the inside of the bag in which the negative electrode is sealed to the outside, and an insulator covering the lead conductor and fused to the end of the inner surface of the bag Because
The lead conductor is a plate-like body, and a plurality of grooves extending in a direction intersecting with the direction in which the lead conductor protrudes are formed on the surface of the portion covered with the insulator on both main surfaces of the lead conductor. Each formed ,
The depth of the groove is 5 to 15% with respect to the thickness of the lead conductor, the opening width of the groove is 2 to 500 μm, and the distance between the grooves is 0.1 to 1.0 mm. . The lead according to claim 1 , wherein the insulator includes at least two layers having different deformation amounts when heated. The lead according to claim 2 , wherein one of the two layers is a layer crosslinked by electron beam irradiation. The lead according to claim 2 , wherein one of the two layers has a higher melting point than the other layer. A bag,
An insulator fused to an end of the inner surface of the bag;
An electrolyte medium enclosed in the bag, a positive electrode, and a negative electrode;
A lead conductor for a positive electrode which is covered with the insulator and protrudes from the inside of the bag to the outside;
A negative electrode lead conductor covered with the insulator and protruding from the inside of the bag to the outside,
At least one of the positive electrode lead conductor and the negative electrode lead conductor is a plate-like body, and is a portion covered with the insulator on both main surfaces of the positive electrode lead conductor and the negative electrode lead conductor. Are formed with a plurality of grooves extending in a direction intersecting the direction in which the lead conductor protrudes, and the depth of the groove is 5 to 15% with respect to the thickness of the lead conductor, The power storage device , wherein an opening width of the grooves is 2 to 500 μm, and an interval between the grooves is 0.1 to 1.0 mm . A lead provided with an electrolyte medium, a positive electrode, and a lead conductor that protrudes from the inside of the bag in which the negative electrode is sealed to the outside, and an insulator that covers the lead conductor and is fused to the end of the inner surface of the bag A manufacturing method of
Forming each of a plurality of grooves extending in a direction intersecting the direction in which the lead conductor protrudes on both main surfaces of the lead conductor which is a plate-like body;
Coating the insulator on the portion where the groove is formed in the lead conductor;
The depth of the groove is 5 to 15% with respect to the thickness of the lead conductor, the opening width of the groove is 2 to 500 μm, and the interval between the grooves is 0.1 to 1.0 mm. A method for manufacturing a lead. The lead manufacturing method according to claim 6 , wherein the grooves are formed on both main surfaces of the lead conductor by pressing.

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