JPH0766787B2 - Flat type non-aqueous electrolyte battery - Google Patents

Description

The present invention relates to a flat type non-aqueous electrolyte battery, and more specifically,
A sealing member made of at least one unit cell, the sealing member made of a thermoplastic resin also serving as an insulating member interposed between the peripheral portions of a pair of metal thin plates facing each other, and the heat fusion between the pair of metal thin plates. The present invention relates to a flat type non-aqueous electrolyte battery configured by incorporating a power generation element in a battery chamber formed by sealing.

[Prior Art] Such flat type batteries have appeared in response to the recent demand for miniaturization and thinning of electric or electronic devices. In particular, the flat type non-aqueous electrolyte battery described above is, for example, Since the thickness can be 0.5 mm or less and a high energy density system can be selected by using a light metal such as lithium as the negative electrode, it is expected to be built in a so-called IC card and used as a power source for it.

The structure of such a flat type non-aqueous electrolyte battery is already known, and is described in, for example, JP-A-60-220533.

The structure of this battery will be described with reference to FIG.
(1) is a stainless steel foil (metal thin plate) which also serves as a negative electrode collector, a negative electrode container and a negative electrode terminal, and a negative electrode (2) of a lithium foil is pressure-bonded to the negative electrode current collecting surface. (3) is a polypropylene non-woven fabric separator, (4) is a mixture of manganese dioxide with fluororesin powder and acetylene black, and is made into a gel of carboxymethyl cellulose, and kneaded to apply to the conductive coating film (5). And dried positive electrode layer. (6) is a stainless steel foil (metal thin plate) that also serves as a positive electrode current collector, a positive electrode container and a positive electrode terminal, and a conductive coating film (5) is applied to the positive electrode current collecting surface. A frame-shaped seal member (7) is provided on the outer peripheral portion between the pair of stainless steel foils (1) and (6), and the seal member (7) is pressed and heated to form the stainless steel foil (1).
It is welded to the peripheral portion of (6) to seal the battery chamber. An electrolyte solution in which lithium perchlorate is dissolved in propylene carbonate is injected into the battery chamber.

In the above-mentioned JP-A-60-220533, the seal member (7)
As the above, a three-layer laminate in which a specific polyolefin resin is combined is proposed, which has excellent heat-welding properties with the stainless steel foils (1) and (6) (heat-welding properties), The sealing member (7) is not deformed and thinned during heat welding (dimensional stability), and short-circuiting between the stainless steel foils (1) and (6) can be prevented by this dimensional stability (insulating property). It was excellent in that it did not react and the electrolyte did not permeate (electrolytic solution resistance), and it had little water permeation (moisture resistance).

[Problems to be Solved by the Invention] By the way, when this battery is incorporated into an electronic component such as an IC card or a device and mounted, a method of reading the circuit becomes a problem. As the lead method, there are a contact terminal lead method, an electric welding lead method, and a soldering lead method. The former two methods are sufficient for equipment used in a static state, but bending such as IC cards is required. It becomes unstable in the dynamic state of, and the soldering lead method is optimal. Further, when directly mounted on a printed circuit board, a soldering lead method is common, and in this case, suitability for an automatic soldering apparatus, that is, heat resistance is required.

However, the seal member disclosed in JP-A-60-220533 cannot withstand the solder melting temperature of 180 ° C., and the seal member deteriorates and peels off.

Therefore, the present invention provides a highly practical flat type non-aqueous electrolyte battery by using the seal member that satisfies the above-mentioned heat-welding property, dimensional stability, and electrolytic solution resistance and does not deteriorate during soldering. The purpose is to do.

[Means for Solving the Problem] In order to achieve this object, the present invention comprises at least one unit cell, and an insulating element interposed between the peripheral portions of a pair of metal thin plates facing each other. In a flat type non-aqueous electrolyte battery constituted by incorporating a power generation element in a battery chamber formed by sealing a sealing member made of a thermoplastic resin also serving as a member and the pair of metal thin plates by heat welding, The seal member
A substrate on which a non-conductive thin film of a metal or a metal oxide is vapor-deposited or sputtered on both sides of a heat-resistant polymer film that does not melt, soften, or flow at a temperature of 180 ° C or less, and a substrate at the heat-welding temperature on both sides of this substrate. Provided is a flat type non-aqueous electrolyte battery comprising a metal adhesive film having a lower melt viscosity and a melting point or a softening point of 140 ° C. or higher that are laminated and integrated.

[Operation] The sealing member in the battery of the present invention is a heat-resistant polymer film that does not melt, soften, or flow at 180 ° C or lower, a thin layer of metal or metal oxide, and a metal having a melting point or softening point of 140 ° C or higher. It is made up of three strong adhesive films, which can be used when the battery is sealed (eg 210
It does not thin at (° C) and therefore does not cause short circuit between stainless steel foils. Although the soldering temperature is about 180 ° C, a large amount of heat is not applied to the metal adhesive film in the soldering process, so if the melting point or softening point of this film is 140 ° C or higher, this soldering No peeling occurs during application. It should be noted that any of the heat-resistant polymer film, thin layer, and metal adhesive film used for this seal member has resistance to an organic electrolytic solution such as propylene carbonate and satisfies the above-mentioned requirements for electrolytic solution resistance. You can In particular, since the heat-resistant polymer film has excellent barrier properties against water vapor and excellent dimensional stability when sealing the battery, it is also advantageous in terms of moisture resistance when the film occupies 50% or more of the cross-sectional area of the sealing member. .

[Explanation of Examples] The structure of the flat type non-aqueous electrolyte battery of the present invention is the same as that of Fig. 1, and only the sealing member is different.

The seal member (7) of the present invention comprises, as shown in FIG. 2, a heat resistant polymer film (71), a non-conductive thin film (72) formed on both surfaces of the heat resistant polymer film (71), and a thin film (72). And a metal adhesive film (73) laminated on top.

Here, the heat-resistant polymer film (71) is required to have dimensional stability and heat resistance capable of stably depositing or sputtering a thin layer (72) of metal or metal oxide, and deformed by heat when the battery is sealed. It must have heat resistance and dimensional stability so that it does not become thin, and that it must not deform, soften, or flow at least below 180 ° C. As a film satisfying these requirements, various tetrafluoroethylene resin films and poly-4-methylpentene-1 (PT
X), biaxially oriented polyethylene terephthalate film (P
ET) etc. Examples of various tetrafluoroethylene-based resins include polytetrafluoroethylene resin (PTFE), polyfluoroalkoxy resin (PFA), ethylene-tetrafluoroethylene copolymer resin (ETFE), and fluoroethylene-hexafluoride. Propylene copolymer resin (FEP), perfluoroethylene-fluoropropylene-perfluorovinyl ether terpolymer resin (EPE) and the like. In order to prevent the permeation of water vapor from the cross section of the seal member (7) or to prevent the dimensional change at the time of sealing the battery, the heat resistant polymer film (71) covers 50% or more of the cross sectional area of the seal member (7). It is preferable to occupy.

The metal adhesive film (73) is required to be welded to the current collectors (1) and (6) at the time of sealing the battery and to have resistance to heat when soldering. Examples of such a film include polypropylene resin and polyamide resin having a melting point or a softening point of 140 ° C. or higher. The polypropylene resin is, in addition to polypropylene, polypropylene or the like graft-modified with an unsaturated carboxylic acid such as maleic acid or acrylic acid. It should be noted that polypropylene resin has low melt viscosity and is easy to flow, and dimensional change is likely to occur when the battery is sealed, and because polyamide resin has water absorbability and high water vapor permeability, either resin is used. In this case, it is desirable that the heat-resistant polymer film (71) has a thickness of 50% or less of the cross-sectional area of the seal member (7) as described above.
It is desirable to occupy at least%.

By the way, since this metal adhesive resin (73) does not have adhesiveness to the heat resistant polymer film (71), both surfaces of this heat resistant polymer film (71) are made of non-conductive metal or metal oxide. The thin layer (72) is formed by vapor deposition or sputtering. In the case of a metal, if its average film thickness is 50 angstroms or less, it becomes a discontinuous island shape and loses its original conductivity and becomes non-conductive. In the case of a metal oxide, there is no such limitation because it is insulative, but when the film thickness is 200 angstroms or more, the cohesive force of the film itself increases and the adhesion with the heat resistant polymer film (71) is increased. Since it becomes difficult to maintain high stability, and the action of the electrolytic solution also causes problems such as peeling, it should be kept below 200 angstrom in this case as well. Aluminum, nickel, chromium, titanium, silicon or the like can be used as the metal, and SiOx, InOx, SnOx (x = 0 to 2) or the like can be used as the metal oxide.

Finally, the seal member (7) is made of each material (71) (72) (7
It is used by sandwiching 3) in an integrated form between two current collectors (1) and (6), but increases the adhesion stability with the current collectors (1) and (6), In order to keep the amount of heat applied low, this sealing member (7) can be divided into two and welded to the respective current collectors (1) and (6) so that they can be integrated at the same time as the battery assembly. Alternatively, the materials (71) (72) (73) are integrated in advance to form the seal member (7).
It is also possible to assemble the battery by welding this to the two current collectors (1) and (6). In any case, no adhesive is used for assembling the seal member (7) and for adhering the seal member (7) and the current collectors (1) and (6).

[Test Example] As seal members, the following five types of sheets (A) to (F) and seal members (G) and (H) for comparison were used. Note that all the seal members are punched out in a frame shape.

○ Sealing material (A) A sheet in which 40 Å thick aluminum is vapor-deposited on both sides of PFA (thickness 100 µ), and polypropylene films (thickness 50 µ) graft-modified with maleic acid are laminated on both sides by the heat lamination method. .

○ Sealing member (B) 40 Å thick nickel was sputtered on both sides of FEP (thickness 100μ) and polypropylene film grafted with maleic acid (thickness 50
(μ) is laminated by a heat lamination method.

○ Sealing material (C) ETFE (thickness 100μ) with thickness of 150 angstrom on both sides
SiO is vapor-deposited, and 12-nylon (with a thickness of 50
(μ) is laminated by a heat lamination method.

○ Sealing material (D) PET (thickness 188μ) both sides of which 40 Å thick aluminum was vapor-deposited, and a polypropylene resin graft-modified with maleic acid was dispersed in petroleum solvent on both sides. Apply with (dry thickness
3.5μ) Dry and laminated sheet.

○ Sealing material (E) TPX (thickness 150μ) is sputtered with 40 Å thick stainless steel on both sides, and polypropylene film grafted with maleic acid on both sides (thickness)
25μ) is laminated by the melt extrusion coating method.

○ Seal member (F) A sheet in which 40 Å thick aluminum is vapor-deposited on both sides of FEP (thickness 100 µ), and 12 nylon films (thickness 40 µ) are laminated on both sides by the melt extrusion coating method.

○ Sealing member (G) A sheet obtained by laminating a polypropylene film graft-modified with maleic acid on both sides of a PET (thickness 188μ) by a heat lamination method.

○ Sealing material (H) 12-nylon (thickness 50μ) on both sides of ETFE (thickness 100μ)
A sheet that is laminated by heat lamination.

The created battery has the same shape as in Fig. 1, and its size is 30 ×
30mm, stainless steel foil (1) and (6) is 30
μ, and the steel (1) used was pressed into a tray. The thickness of the obtained battery is 0.5 mm.

Welding of the stainless steel foils (1) and (6) and the sealing members (A) to (H) was carried out at a temperature of 210 ° C and a pressure of 5 kg / c.
It was performed by heating and pressurizing under conditions of m ² and time of 10 seconds. Stainless steel foil (1) (6) at this time,
Table 1 shows the adhesive strength (g / 15 mm) of each seal member (A) to (H).

The adhesive strength is measured by T-shaped peeling at a peeling speed of 300 mm / min.

The seal member (G) is made of polypropylene film.
Nylon film and E in the seal member (H) between PET
Peeling occurred between the TFEs.

In addition, the lead wire is soldered to the seal portion (8) of the battery made by using the seal members (A) to (F) by using JIS solder, and further, the lead wire is soldered under the conditions of 60 ° C. and 90% RH for 90 minutes. As a result of storage for a day, there was no phenomenon such as peeling of the seal portion, increase in internal resistance, increase in battery thickness (blister), and liquid leakage.

[Effect] As described in detail above, according to the present invention, it is possible to realize a reliable hermetic seal having excellent dimensional stability and no fear of short circuit.
In addition, the flat non-aqueous electrolyte battery can be provided which has a suitable solderability as an electronic component incorporated in a device such as an IC card and has stable quality without making a great change in the battery element.

The basic configuration of the present invention is also effective as a non-aqueous electrolyte battery that does not require solderability.

[Brief description of drawings]

FIG. 1 is a sectional view of a flat type non-aqueous electrolyte battery, and FIG. 2 is a sectional view of a seal member of the present invention. (1) (6) …… Stainless steel foil (2) …… Negative electrode, (3) …… Separator (4) …… Positive electrode layer, (5) …… Conductive coating film (7) …… Seal member (71) ) …… Heat-resistant polymer film (72) …… Metal or metal oxide thin film (73) …… Metal adhesive film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 61-126766 (JP, A) JP 60-221952 (JP, A) JP 55-119352 (JP, A) JP 58- 87753 (JP, A)

Claims (5)

[Claims] 1. A sealing member made of a thermoplastic resin, which is composed of at least one unit cell, and is interposed between respective peripheral portions of a pair of metal thin plates facing each other, and which is made of a thermoplastic resin, and the pair of metals. In a flat type non-aqueous electrolyte battery configured by incorporating a power generation element in a battery chamber that is hermetically sealed by heat welding with a thin plate, the sealing member does not melt, soften or flow at a temperature of 180 ° C or less. A substrate on which a non-conductive thin film of a metal or a metal oxide is vapor-deposited or sputtered on both sides of a heat-resistant polymer film, and both sides of this substrate have a lower melt viscosity at the heat welding temperature than the substrate and have a melting point or softening point. 14
A flat type non-aqueous electrolyte battery comprising a metal adhesive film at 0 ° C. or higher laminated and integrated. 2. The flat type non-aqueous electrolyte battery according to claim 1, wherein the heat-resistant polymer film occupies 50% or more of the cross-sectional area of the sealing member. 3. The flat according to claim 1) or 2), wherein the metal vapor-deposited or sputtered on both sides of the heat-resistant polymer film has an average thickness of 50 angstroms or less. Type non-aqueous electrolyte battery. 4. The method according to claim 1 or 2, wherein the metal oxide vapor-deposited or sputtered on both sides of the heat-resistant polymer film has an average thickness of 200 angstroms or less. Flat type non-aqueous electrolyte battery. 5. The heat-resistant polymer film is a fluorinated ethylene resin (polytetrafluoroethylene resin, polyfluoroalkoxy resin, ethylene-tetrafluoroethylene copolymer resin, fluorinated ethylene-hexafluoropropylene copolymer resin). , Perfluoroethylene-fluoropropylene-perfluorovinyl ether terpolymer resin, etc.), poly-4-methylpentene-
The flat type non-water according to any one of claims 1) to 4), wherein the mono- or biaxially-stretched polyethylene terephthalate resin and the metal adhesive film are made of polypropylene-based or polyamide-based resin. Electrolyte battery.