JP2000235850A - Layered polymer electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of battery performance while improving the strength of a connection part of a lead layered product of an electrode to an external terminal by laminating lead parts of at least any one of a positive electrode and a negative electrode, and reinforcing this layered product of the lead part with a reinforcing plate made of the same kind of metal with the lead part of the electrode and having thickness at a specified value or more in relation to the thickness of the lead part of the electrode. SOLUTION: An outer case 4 is sealed by fusing a laminated film of denatured polyolefin film to be used as the outer case 4. A layered product of a lead part 1c of a positive electrode and a positive electrode terminal 5 are connected to each other at a seal part 4a of the outer case 4 by reinforcing the layered product of the lead part 1c with a reinforcing plate 7 having thickness at twice or more of the thickness of the lead part 1c of the electrode and welding the positive electrode terminal 5 to the reinforcing plate 7. A seal layer 4b formed of a denatured polyolefin film of the most inside layer of the outer case 4 melted by heating corresponds to the seal part 4a of the outer case 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacked polymer electrolyte battery, and more particularly, to a stacked polymer electrolyte battery having a stacked electrode group in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are stacked via a polymer electrolyte. In particular, the present invention relates to a laminated polymer electrolyte battery suitable for use as a power source for portable devices such as personal computers and mobile phones.

[0002]

2. Description of the Related Art In a polymer electrolyte battery, the electrolyte can be formed into a sheet. By using the sheet electrolyte, a battery having a large area and a thin shape such as an A4 plate or a B5 plate can be manufactured. As a result, application to various thin products has become possible, and the range of use of batteries has been greatly expanded.
Batteries using this polymer electrolyte have excellent safety and storage properties, including leakage resistance, and are thin and flexible, so batteries can be designed according to the shape of equipment. Has features not found in

[0003] This polymer electrolyte battery usually uses a laminate film having an aluminum film as a core material as an outer package, laminates a thin sheet-like electrode and a sheet-like polymer electrolyte layer, and forms the laminate with the above-mentioned laminate film. The battery is finished by being sealed with an outer package and sealed.

In this polymer electrolyte battery, in order to make the electrodes thin, a metal foil is usually used as a current collector, an aluminum foil is used as a positive electrode current collector, and a copper is used as a negative electrode current collector. Uses foil. And the external terminals of the battery,
As the positive terminal and the negative terminal used for connection with the battery-powered device, usually, because of the ease of connection with the battery-powered device, etc.
Nickel foil or ribbon is used.

The electrical connection between these electrodes and external terminals is
Normally, during the production of the positive electrode, the exposed portion of the aluminum foil is left without forming a positive electrode mixture layer on a part of the aluminum foil, and the exposed portion of the aluminum foil is used as a lead portion for connection with a positive electrode terminal as an external terminal, or One end of an aluminum lead body is connected to an aluminum lead part by welding or the like, and the other end of the aluminum lead body is used as a connection part with a positive terminal as an external terminal. When forming the negative electrode, leave the exposed portion of the copper foil without forming the negative electrode mixture layer on a part of the copper foil, or use it as a lead portion for connection with the negative electrode terminal as an external terminal, or One end of a copper lead body is connected to the lead portion, and the other end of the copper is used as a connection portion to a negative electrode terminal as an external terminal.

However, the aluminum lead and its lead body, the copper lead and its lead body, and the like have low strength due to their small thickness, and the strength of the connection between them and external terminals is also low. There was a problem of low.

That is, the connection between them and the external terminals is
Usually, resistance welding, ultrasonic welding, etc. are performed, but the welding strength of each is low, especially welding of aluminum and nickel on the positive electrode side is very difficult, and the welding strength is very low. was there.

Further, when a high voltage or a high capacity is demanded from a battery-using device, this polymer electrolyte battery takes advantage of the feature that the electrodes and the polymer electrolyte can be made into a thin sheet shape while utilizing a plurality of sheet shapes. A positive electrode and a plurality of sheet-shaped negative electrodes are laminated via a polymer electrolyte to form a laminated electrode group, and these electrodes are connected in series or in parallel to achieve a high voltage or a high capacity required by equipment using a battery. I have been able to respond.

However, when such a laminated electrode group is provided, a plurality of positive electrode aluminum lead portions and a plurality of negative electrode copper lead portions constituting the laminated electrode group are laminated to form an external terminal. Alternatively, it is necessary to connect the lead body to the external terminal (the lead body connected to the external terminal is referred to as “lead body to the external terminal” in this way), and the connection becomes more difficult. Was.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides a laminate of electrode lead portions and an external terminal or a lead to the external terminal in a laminated polymer electrolyte battery. It is an object of the present invention to provide a stacked polymer electrolyte battery having high reliability in battery performance by increasing the strength of a connection portion of the battery.

[0011]

SUMMARY OF THE INVENTION The present invention provides a positive electrode comprising a positive electrode mixture layer formed on at least one surface of an aluminum current collector and a negative electrode mixture on at least one surface of a copper current collector. In a laminated polymer electrolyte battery in which a laminated electrode group in which a plurality of negative electrodes each having a layer are formed and a plurality of laminated layers are interposed via a polymer electrolyte is packaged with a package, a lead portion of at least one of the positive electrode and the negative electrode is formed. The laminate of the lead portion is reinforced with a reinforcing plate made of the same kind of metal as the lead portion of the electrode and having a thickness of twice or more the thickness of the lead portion of the electrode. The above object has been attained by connecting the laminate or reinforcing plate of the electrode lead to the external terminal or the lead to the external terminal.

That is, by adopting the above configuration,
The connection portion between the electrode lead portion laminate or the lead portion laminate and the external terminal or the lead body to the external terminal,
Since they are reinforced with reinforcing plates, their connection strength is increased, and even if mechanical force such as dropping or vibration is applied, damage to the connection part is suppressed, and stable battery performance can be obtained. A stacked polymer electrolyte battery having high performance reliability can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as a current collector of a positive electrode, aluminum foil, punched metal, mesh, expanded metal, and the like can be used. Usually, aluminum foil is used. The current collector of the positive electrode preferably has a thickness of 20 μm or less in view of reducing the thickness of the positive electrode. In the present invention, even if the current collector has such a small thickness, the lead constituted by the exposed portion is used. Since the portion is reinforced with a reinforcing plate and then welded, there is no possibility of breakage. However, if it is too thin, wrinkles may occur when the positive electrode mixture-containing paste is applied during the production of the positive electrode, or the film may be broken by pulling. Therefore, the thickness is 20 μm or less and 10 μm or less as described above. The above is preferred. In this specification, the description will be made mainly for the positive electrode, but the concept is the same for the negative electrode.

In the lead portion on the positive electrode side, usually, an exposed portion of the current collector is left without forming a positive electrode mixture layer on a part of the aluminum current collector at the time of manufacturing the positive electrode, and the lead portion is used as the lead portion. Provided by However, the lead portion is not necessarily required to be integrated with the current collector from the beginning,
The current collector may be provided by connecting an aluminum foil or the like later.

The positive electrode terminal as an external terminal is preferably made of nickel or nickel-plated metal foil or ribbon of iron, copper, stainless steel, or the like from the viewpoint of easy connection with equipment using a battery. 30-300 μm,
Particularly, the thickness is preferably from 40 to 200 μm. That is, by setting the thickness to 30 μm or more, it is possible to prevent the positive electrode terminal from being cut at the time of welding, to prevent the terminal from being broken by pulling or bending, and by setting the thickness to 300 μm or less, The generation of a gap can be prevented.

When the aluminum lead is used to connect to the positive electrode terminal, the thickness of the aluminum lead is 30 to 3 as in the case of the positive electrode.
00 μm, particularly preferably 40 to 200 μm. Such a lead body may be used especially when the current collector of the positive electrode is thin and the exposed part is used as the lead part, and when it is not preferable to directly connect to the positive terminal as an external terminal in terms of strength. preferable.

As the reinforcing plate for reinforcing the laminate of the aluminum lead portion of the positive electrode, an aluminum plate is used from the viewpoint of using the same kind of metal as the aluminum lead portion. 2 of thickness
More than doubled. This is because by making the thickness of the reinforcing plate more than twice the thickness of the lead, the tip of the welding jig (the electrode of the welding machine for resistance welding and the horn for ultrasonic welding) becomes uniform (pressing force). Is appropriately dispersed), in order to make it easier to obtain welding conditions having good strength over a large area. The thicker this reinforcing plate is, the more suitable in terms of reinforcement, but if it is too thick, Since the reliability of the seal portion is lost, usually 30 to 30
Those selected from the range of 0 μm are preferably used, and those selected from the range of 40 to 200 μm are more preferably used.

The aluminum lead portion laminate may be reinforced by the aluminum reinforcing plate in any manner as long as the aluminum lead portion can be reinforced. For example, the lead portion laminate and the positive electrode terminal or the lead may be reinforced. The connection portion with the body may be sandwiched by a reinforcing plate, or the lead laminate may be reinforced with a reinforcing plate in such a manner as to sandwich the lead laminate, and the reinforcing plate and the positive electrode It may be connected to a terminal or a lead body, or furthermore, a reinforcing plate may be applied to one surface of the lead portion laminate to reinforce the lead portion laminate with the reinforcing plate, and the lead portion laminate may be opposite to the lead portion laminate. The surface on the side may be a connection portion with a positive electrode terminal or a lead body. As a method of reinforcing the laminate of the lead portion with the reinforcing plate, a method of fixing the laminate of the lead portion and the reinforcing plate by welding, soldering, caulking, or the like can be adopted. The method is suitable.

As a method for connecting the above-mentioned aluminum lead portion laminate or reinforcing plate to the positive electrode terminal or the lead, for example, resistance welding, ultrasonic welding, laser welding, soldering, caulking, a method using a conductive adhesive, or the like. Although various methods can be adopted, welding is particularly suitable.

As the current collector of the negative electrode, copper foil, punched metal, mesh, expanded metal, etc. can be used.
Usually, copper foil is used. As the thickness of the current collector of the negative electrode, for the same reason as in the case of the current collector of the positive electrode,
5 to 20 μm is preferable, and the lead portion on the negative electrode side also has
Usually, it is provided by leaving an exposed portion of the current collector without forming the negative electrode mixture layer on a part of the copper current collector at the time of manufacturing the negative electrode and using the current collector as a lead portion. However, the lead portion on the negative electrode side is not necessarily required to be integrated with the current collector from the beginning, and may be provided by connecting a copper foil or the like to the current collector later.

A negative terminal as an external terminal on the negative side includes:
As in the case of the positive electrode terminal, a metal foil or ribbon of nickel or nickel-plated iron, copper, stainless steel or the like is preferably used, and its thickness is 30 to 300 μm, particularly 40 μm, as in the case of the positive electrode terminal. ~ 200 µm is preferred. When connecting to the negative electrode terminal using a copper lead, the thickness of the copper lead is 30 to 300 μm, particularly 40 to 2 μm, as in the case of the negative electrode terminal.
00 μm is preferred.

As the reinforcing plate for reinforcing the copper lead laminated body of the negative electrode, a copper plate is used from the viewpoint of using the same kind of metal as the copper lead, and the thickness thereof is equal to the thickness of the copper lead. More than doubled. This is based on the same reason as the reinforcing plate on the positive electrode side, and, similarly to the reinforcing plate on the positive electrode side, is usually 30 to 30.
Those selected from the range of 0 μm are preferably used, and those selected from the range of 40 to 200 μm are more preferably used.

The reinforcement of the copper lead portion laminate by the copper reinforcement plate may be performed in the same manner as the reinforcement of the aluminum lead portion laminate by the aluminum reinforcement plate.

Examples of a method for connecting the above-mentioned copper lead laminated body or reinforcing plate to the negative electrode terminal or lead body include resistance welding, ultrasonic welding, laser welding, soldering, caulking, and a method using a conductive adhesive. Various methods can be employed, but welding is particularly suitable.

As the outer package, for example, a laminated film having a three-layer structure composed of a nylon film or a polyester film-aluminum film-modified polyolefin film is used, and the wider the sealing portion, the more advantageous from the viewpoint of strength. However, if the width of the sealing part of the outer body is increased, the outer body becomes larger, the volume and weight of the battery increase, which hinders miniaturization,
If the width of the sealing part is increased without changing the size of the exterior body, the electrodes must be made smaller accordingly, which hinders the increase in capacity. 5m at least 1mm on both sides from center
m (that is, 2 to 10 as the width of the sealing portion).
mm).

As described above, welding of aluminum and nickel is particularly difficult, and there is a problem that if an electrolyte is present between aluminum and nickel, a local battery is formed and corrosion of aluminum occurs. The connection between the positive electrode terminal of the aluminum lead portion laminate or the positive electrode terminal connected to the aluminum lead portion connected to the aluminum lead portion laminate is performed by the seal portion of the exterior body. Can be solved.

[0027]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples. The preparation of the positive electrode, the negative electrode, and the polymer electrolyte commonly used in the following Examples and Comparative Examples will be described prior to the description of the Examples and the like.

Preparation of positive electrode: LiCoO which is a positive electrode active material
₂ 90 parts by weight, 5 parts by weight of carbon black is a conductive aid, polyvinylidene fluoride 5 parts by weight of a binder mixture of N- methylpyrrolidone to be uniform as a solvent, to prepare a positive electrode mixture-containing paste.

The paste containing the positive electrode mixture was coated to a thickness of 20 μm.
20 mg / cm of positive electrode mixture on one side of aluminum foil
² (However, the positive electrode mixture layer after drying) is uniformly applied to both sides and dried to form a positive electrode mixture layer, then calendered, and the thickness of one side of the positive electrode mixture layer is reduced. 65μ
m. It was cut into a size of 70 mm × 40 mm to obtain a positive electrode. However, in producing the above positive electrode, the positive electrode mixture-containing paste was not applied to part of the aluminum foil, leaving an exposed portion of the aluminum foil, and using the exposed portion as a lead for connection with the positive electrode terminal as an external terminal. Department.

Preparation of negative electrode: 77 parts by weight of graphite as the negative electrode active material, 8 parts by weight of Carbotron P (trade name, low crystalline carbon having an average particle size of 22 μm, manufactured by Kureha Chemical Industry Co., Ltd.), and polyvinylidene fluoride as a binder 15 parts by weight were uniformly mixed using N-methylpyrrolidone as a solvent to prepare a negative electrode mixture-containing paste.

This negative electrode mixture mixture paste is 10 μm thick.
The amount of the negative electrode mixture on one side after drying on both sides of the copper foil was 12 mg /
cm ² (however, the amount of the negative electrode mixture after drying) is applied uniformly, dried to form a negative electrode mixture layer, and then calendered, and the thickness of the negative electrode mixture layer on one side is reduced to 65 μm. Was adjusted. This was cut into a size of 72 mm × 42 mm to obtain a negative electrode. However, in producing the above negative electrode, the negative electrode mixture-containing paste was not applied to part of the copper foil, leaving an exposed portion of the copper foil, and using the exposed portion as a lead for connection with the negative electrode terminal as an external terminal. Department.

Fabrication of the positive electrode unit: A polyimide tape having a thickness of 50 μm and a width of 3 mm is adhered from both sides to a portion near the lead portion of the positive electrode fabricated as described above, thereby preventing short-circuit and maintaining strength of the portion. Was planned. In addition, the surface of the lead portion, which was to be connected to the positive electrode terminal, was covered with a heat-peeling tape from which the adhesiveness of the adhesive surface was lost by heat. This positive electrode is used as a support for the gel polymer electrolyte. The non-woven fabric is a polybutylene terephthalate non-woven fabric having a thickness of 30 μm and a basis weight of 12 g / m ² [manufactured by NKK, MB1230 (trade name)].
Wrapped in

Fabrication of the negative electrode unit: An imide tape having a thickness of 50 μm and a width of 3 mm was adhered from both sides to a portion near the lead portion of the negative electrode to prevent short-circuit and maintain strength in the portion. In addition, the surface of the lead portion, which is to be connected to the negative electrode terminal, was covered with a heat-peeling tape from which the adhesive surface loses tackiness due to heat. Then, this negative electrode is used as a holding body for the gel polymer electrolyte in a polybutylene terephthalate nonwoven fabric having a thickness of 30 μm and a basis weight of 12 g / m ² [manufactured by NKK, MB
1230 (trade name)].

Preparation of gel polymer electrolyte: volume ratio of propylene carbonate to ethylene carbonate 1: 1
As a polymerization initiator, an electrolyte prepared by dissolving 1.22 mol / l of LiPF _{6 in} a mixed solvent of
4,6-Trimethylbenzoyldiphenylphosphine oxide (Lucillin TPO (trade name), manufactured by BSF Japan Co., Ltd.) was previously added and dissolved in the monomer component at 2% by weight, and dipentaerythritol hexaacrylate was added thereto. Was added 10 minutes before the start of use so that the concentration became 6% by weight, and mixed to prepare an electrolytic solution containing a gelling component. Hereinafter, the electrolytic solution containing the gelling component is referred to as “gelling component-containing electrolytic solution”.

The gelled component-containing electrolyte is absorbed by the positive electrode unit and the negative electrode unit, respectively, under reduced pressure. The positive electrode unit and the negative electrode unit impregnated with the gelled component-containing electrolyte are placed in a polyethylene bag. The bag was sealed.

From both sides of the bag containing the positive electrode unit and the bag containing the negative electrode unit impregnated with the gelling component-containing electrolyte, Fusion UV Systems Japan Co., Ltd.
UV light was applied for 10 seconds at an illuminance of 1 W / cm ² using a UV light irradiating device manufactured by Co., Ltd. to form a gel polymer electrolyte having a built-in support around the positive and negative electrodes.

The positive electrode and the negative electrode each having the gel polymer electrolyte formed around them as described above are taken out of the bag, respectively.
The hot release tape was peeled off from the lead portion by blowing hot air at 150 ° C. onto the lead portion, and then the five negative electrodes and four positive electrodes were alternately laminated to form a laminated electrode group. Hereinafter, connection with an external terminal was performed by the method described in Examples and Comparative Examples, and a laminate film having a three-layer structure composed of a nylon film, an aluminum film, and a modified polyolefin film was prepared as a package for covering the laminated electrode group.

EXAMPLE 1 A positive electrode lead laminate (a laminate of four lead portions composed of exposed portions of four aluminum foils) in the above-mentioned laminated electrode group was made of aluminum having a thickness of 100 μm and a width of 3 mm. Sandwiched between two reinforcing plates made of aluminum, and 40 μm thick as a positive electrode terminal
m of nickel ribbon, and using a 947M ultrasonic oscillator manufactured by Branson as a welding machine, welding time 1 sec.
c, pressure 3.2 kg / cm ² , amplitude 85%
Welded under the following conditions. The position of the welded portion was made to coincide with the seal portion when the laminated electrode group was packaged with a package. In the same manner as described above, a negative electrode lead portion laminate (a laminate of five lead portions composed of five exposed portions of copper foil) in the laminated electrode group was made of copper having a thickness of 100 μm and a width of 3 mm. Between the two reinforcing plates, and a negative electrode terminal having a thickness of 40
One μm nickel ribbon was stacked and welded using the same welding machine as above under the conditions of a welding time of 1 sec, a pressure of 4 kg / cm ² , and an amplitude of 100%. The position of this welded portion was also set to match the sealed portion when the laminated electrode group was packaged with a package. Thereafter, the laminated electrode group was packaged with a package and sealed, thereby producing a laminated polymer electrolyte battery.

The width of the above welded portion was 2 mm on both the positive electrode side and the negative electrode side, and the width of the sealing portion of the outer package was 4 mm in each case.

In describing the structure of this polymer electrolyte battery, a positive electrode unit having a polymer electrolyte formed around it as described above (hereinafter referred to as a "polymer electrolyte holding positive electrode") and a negative electrode unit having a polymer electrolyte formed therearound (Hereinafter, this is referred to as “Polymer
That is, as shown in FIG. 1,
The polymer electrolyte-carrying positive electrode 10 has a support 3 around the positive electrode 1.
It is constituted by forming a gel-like polymer electrolyte 3 containing a.

Further, as shown in FIG. 2, the polymer electrolyte holding negative electrode 20 is formed by forming a gel polymer electrolyte 3 having a support 3a built in around the negative electrode 2.

Then, the polymer electrolyte holding positive electrode 10
Are laminated with five sheets of the polymer electrolyte holding negative electrode 20,
A stacked electrode group is configured as shown in FIG. That is, 1
The fifth sheet of the polymer electrolyte holding negative electrode 20 and the fifth sheet of the polymer electrolyte holding negative electrode 20 are respectively arranged in the outermost layer, and between them, four sheets of the polymer electrolyte holding cathode 10 and three sheets of the polymer electrolyte holding negative electrode 20 are alternately arranged. It is laminated. Then, between the polymer electrolyte holding positive electrode 10 and the polymer electrolyte holding negative electrode 20, as shown in FIG.
The polymer electrolyte 3 formed around the positive electrode 1 and the polymer electrolyte 3 formed around the negative electrode 2 between the positive electrode 1 and the negative electrode 2 form a polymer electrolyte layer having a sufficient thickness with them. Thereby, the positive electrode 1 and the negative electrode 2 are sufficiently separated.

The battery was constructed by combining the above-described laminated electrode group with the one shown in FIG.
As shown in the figure, the package is formed by sealing with a package 4 made of a laminate film having a three-layer structure of a nylon film-aluminum film-modified polyolefin film. In this battery, the positive terminal 5 and the negative terminal 6 are external terminals.

FIG. 5 schematically shows a connection portion between the laminate of the aluminum lead portion 1c of the positive electrode 1 of the battery shown in FIG. 3 and the positive electrode terminal 5 and the vicinity thereof. Is performed at the sealing portion 4a. That is, the two exterior bodies 4 are used, and the sealing is performed by heat-sealing the modified polyolefin film of the laminate film used as the exterior body 4. The connection with the terminal 5 is made by reinforcing the laminate of the lead portions 1c with the reinforcing plate 7, and the reinforcing plate 7
(Ie, the connection between the laminate of the lead portion 1c and the positive electrode terminal 5 is made by welding via the reinforcing plate 7), and the welding is performed by the sealing portion of the exterior body 4. 4a, the connection part of which is located in the region of the sealing part 4a of the exterior body 4.

Reference numeral 4b denotes a seal layer formed by melting the innermost modified polyolefin film of the outer package 4 by heating. The seal layer 4b corresponds to the sealing portion 4a of the outer package 4. The airtightness inside the battery is maintained by the layer 4b.

As shown in FIG. 4, the positive electrode 1 is formed by forming a positive electrode mixture layer 1b on both surfaces of a current collector 1a made of aluminum, and a polymer electrolyte 3 is formed around the positive electrode 1. . The negative electrode 2 is a current collector 2a made of copper foil.
, A negative electrode mixture layer 2b is formed on both surfaces thereof, and a polymer electrolyte 3 is formed around the negative electrode 2. Further, the negative electrode 2 is not shown in FIG. 5, but as in the case of the positive electrode 1, a lead portion 2a is laminated, and a laminate of the lead portion 2a is schematically shown in FIG. The copper reinforcing plate 7 and the nickel negative electrode terminal 6 are welded and connected to each other at the sealing portion 4 a of the exterior body 4. However, the connection with the negative electrode terminal 6 on the negative electrode 2 side does not necessarily need to be made at the sealing portion of the exterior body. In addition, FIGS. 1 to 5 are schematic views, and the dimensional ratios of the respective components are not always accurate. 1 and 2, the illustration of the current collector and the lead portion is omitted.

Example 2 A laminate of the aluminum lead portion 1c of the positive electrode was reinforced with an aluminum reinforcing plate 7 in the same manner as in Example 1, and the aluminum reinforcing plate 7 was provided with a 100 μm thick aluminum lead. One end of the body was welded and connected, the other end of the aluminum lead body was welded and connected to the positive electrode terminal, and a laminate of the copper lead 2c of the negative electrode was formed as in Example 1. Similarly, it is reinforced with a copper reinforcing plate, and one end of a copper lead having a thickness of 100 μm is connected to the copper reinforcing plate by welding, and the other end of the copper lead is welded to a negative electrode terminal. A laminated polymer electrolyte battery was produced in the same manner as in Example 1 except that the battery was connected by connecting.

The connection between the aluminum lead body of the positive electrode of the battery and the positive electrode terminal by welding is performed at the sealed portion of the exterior body, and the width of the connection portion is 2 mm and the width of the sealed portion is 4 mm. The connection between the copper lead body of the negative electrode and the negative electrode terminal by welding is also performed at the sealed portion of the exterior body, and the width of the connection portion is 2 mm and the width of the sealed portion is 4 mm.

FIG. 6 schematically shows the connection between the aluminum lead and the positive electrode terminal 5 connected to the laminate of the positive electrode lead of the battery of Example 2 and the vicinity thereof. The connection between the lead body 8 and the positive electrode terminal 5 is made at the sealing portion 4 a of the exterior body 4. That is, also in the second embodiment, as in the first embodiment, two exterior bodies 4 are used, and the seal is formed by heat-sealing the modified polyolefin film of the laminated film used as the exterior body 4. The connection between the aluminum lead body 8 connected to the laminate of the lead body 1c of the positive electrode 1 and the positive electrode terminal 5 is performed at the sealing portion 4a of the exterior body 4, and the connection is made by the exterior body. 4 is located in the area of the sealing portion 4a. The difference between the battery of the second embodiment and the battery of the first embodiment is that the connection between the laminate of the lead portions 1c of the positive electrode 1 and the lead body 8 is made on the inner side (from the sealing portion 4a of the exterior body 4). (Internal side of the battery), and the connection between the lead body 8 and the positive electrode terminal 5 is made at the sealing portion 4a of the exterior body 4. That is, on the inner side of the sealing portion 4a of the exterior body 4, the laminated body of the aluminum lead portions 1c of the positive electrode 1 is reinforced by the aluminum reinforcing plate 7, and the reinforcing plate 7 is provided with the aluminum lead body 8. One end is connected by welding, and the other end of the lead body 8 and the positive electrode terminal 5 are connected by welding at the sealed portion of the exterior body 4.

In this way, the thickness of the sealing portion 4a of the exterior body 4 can be made smaller than in the case of the first embodiment. The width of the connecting portion between the lead body 8 and the positive electrode terminal 5 is 2 mm, and the width of the sealing portion is 4 mm. Although not shown in FIG. 6, on the negative electrode 2 side, similarly to the positive electrode 1 side, the laminate of the lead portions 2 c of the negative electrode 2 is reinforced with a copper reinforcing plate. One end of the copper lead body is connected by welding, and the other end of the copper lead body is connected by welding at the sealing portion 4a of the negative electrode terminal 6 and the exterior body 4, and The width is 2 mm and the width of the sealing part is 4 mm.

The welding conditions for the reinforcing plate 7 for reinforcing the laminate of the lead portions 1c of the positive electrode 1 and the aluminum lead body 8 and the welding conditions for the lead body 8 and the positive electrode terminal 5 are the same as those in the first embodiment. The welding conditions of the reinforcing plate 7 for reinforcing the laminate of the aluminum lead portions 1c and the positive electrode terminal 5 are the same, and the reinforcing plate for reinforcing the laminate of the lead portions 2c of the negative electrode 2 and a copper lead And the welding conditions between the lead body and the negative electrode terminal are the same as the welding conditions between the negative electrode terminal 6 and the reinforcing plate for reinforcing the laminate of the copper lead portions 2c of the first embodiment.

Example 3 A laminated polymer electrolyte battery was manufactured in the same manner as in Example 1 except that a metal reinforcing plate was provided only on the side opposite to the side connected to the external terminals of the lead portion laminate. did.

FIG. 7 schematically shows a connection portion between the laminate of the positive electrode 1 of the battery of Example 3 and the aluminum lead portion 1c and the positive electrode terminal and the vicinity thereof.

In the battery of the third embodiment, the positive electrode terminal 5 is directly connected to the lead 1c of the positive electrode 1 by welding, and the reinforcing plate 7 is provided only from the side opposite to the positive electrode terminal 5 (the upper side in FIG. 7). The laminate of the lead portion 1c is reinforced. Although not shown in FIG. 7, the negative electrode terminal 6 is connected to the lead portion 2 of the negative electrode 2 on the negative electrode 2 side, similarly to the positive electrode 1 side.
c, and the reinforcing plate reinforces the laminated body of the lead portion 2c only from the side opposite to the negative electrode terminal. The welding conditions for the positive electrode terminal 5 and the laminate of the lead portion 1c are the same as the welding conditions for the positive electrode terminal 5 and the reinforcing plate 7 in the first embodiment.
The welding conditions for the laminate of c were the same as the welding conditions for the negative electrode terminal 6 and the reinforcing plate of the first embodiment.

Example 4 A laminated polymer electrolyte battery was fabricated in the same manner as in Example 2 except that the metal reinforcing plate was provided only on the side opposite to the side of the lead portion laminate connected to the lead body. did.

FIG. 8 schematically shows a connection portion between an aluminum lead 8 connected to a laminate of aluminum lead portions 1c of the positive electrode 1 of the battery of Example 4 and the positive electrode terminal 5, and the vicinity thereof. .

In the battery of the fourth embodiment, one end of the aluminum lead body 8 is connected directly to the aluminum lead part 1c by welding, and the reinforcing plate 7 is on the side opposite to the lead part 8. The laminate of the lead portion 1c is reinforced only from above (that is, from the upper side in FIG. 8). Although not shown in FIG. 8, on the negative electrode 2 side, similarly to the positive electrode 1 side, a copper lead body is directly connected to the lead portion 2 c of the negative electrode 2 by welding, and the reinforcing plate is The laminate of the lead portion 2c is reinforced only from the side opposite to the lead body. The laminate of the lead 1c of the positive electrode 1 and the lead 8
And the welding conditions between the lead body 8 and the positive electrode terminal 5 are the same as the welding conditions between the positive electrode terminal 5 and the reinforcing plate 7 of the first embodiment. The welding conditions between the lead and the copper lead and the welding between the lead and the negative electrode terminal 6 are the same as the welding conditions between the copper lead and the reinforcing plate 7 of the first embodiment. 6 to 8 are also schematically shown, and the dimensional ratio of each component is not always accurate.

COMPARATIVE EXAMPLE 1 A connection by welding a laminate of a positive electrode lead made of aluminum and a positive electrode terminal made of a nickel ribbon and a connection by welding a laminate of a copper lead portion made of a negative electrode and a negative electrode terminal made of a nickel ribbon. Was performed in the same manner as in Example 1 except that was performed without reinforcing with a reinforcing plate.

COMPARATIVE EXAMPLE 2 A reinforcing plate was used to connect the positive electrode aluminum lead laminated body and the aluminum lead body by welding and the negative electrode copper lead laminated body to the copper lead body by welding. A laminated polymer electrolyte battery was produced in the same manner as in Example 2 except that the test was performed without using the same.

The connection portion (welded portion) between the aluminum lead portion of the positive electrode and the nickel positive electrode terminal or aluminum lead body by the drop test of the batteries of Examples 1-4 and Comparative Examples 1-2, and the negative electrode Of the connection part (weld part) between the copper lead part and the nickel negative electrode terminal or the copper lead body, and the presence or absence of liquid leakage after storage for 20 days in an atmosphere of 60 ° C. and 90% relative humidity. Examined. Table 1 shows the results. In the drop test, the battery was dropped on concrete from a height of 180 cm, and the presence or absence of peeling of a welded portion between the lead portion and an external terminal made of a lead body or a nickel ribbon was examined. This drop test was performed on each of the ten batteries, and Table 1 shows the number of batteries subjected to the test in a denominator, and the number of batteries that caused peeling of the welded portion in a numerator. The presence or absence of liquid leakage was checked by visual observation. Table 1 also shows the thickness of the sealing portion of the outer package on the positive electrode side.

[0061]

[Table 1]

As is clear from the results shown in Table 1, in Examples 1 to 4, there was no peeling of the connection portion (welded portion) in the drop test, and the laminate of the lead portion of the electrode and the lead member or the nickel ribbon did not. The external terminal had sufficient connection strength (welding strength). In Examples 1 to 4, there was no liquid leakage.

It should be noted that the thickness of the sealing portion is referred to in the first and third embodiments because the connecting portion between the laminate of the lead portion and the external terminal is formed by the sealing portion of the outer package. Although the portion is thick, the sealing portion may hinder the wiring or installation of other components such as a substrate. However, as in the second and fourth embodiments, the laminate of the lead portion and the lead If the body is done inside the battery, and the above-mentioned lead body and the external terminal are connected at the sealing part of the exterior body,
This is to show that the thickness of the seal portion can be reduced and such a concern can be eliminated. Further, from the viewpoint of strength, it is preferable that the reinforcement by the reinforcing plate is performed from both sides of the laminate of the lead portions of the electrodes. With only one side of reinforcement, if the drop height is set to 3 m, in the third and fourth examples, the connection portion was damaged at a probability of about 1/10.

In the gelation of the polymer electrolyte, in addition to those shown in the above examples, for example, those which gel the polymer, radically polymerizable unsaturated polyester, radically polymerizable acrylic epoxy acrylate, urethane Photocurable resins such as acrylates, polyester acrylates, alkyd acrylates, and silicon acrylates may be gelled using ultraviolet rays or electron beams.

[0065]

As described above, according to the present invention, the connection strength between the laminate of the electrode lead portions and the external terminal or the lead body is increased, and a laminated polymer electrolyte battery having high battery performance is provided. I was able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a polymer electrolyte holding positive electrode used in a stacked polymer electrolyte battery according to Example 1 of the present invention.

FIG. 2 is a cross-sectional view schematically showing a polymer electrolyte-holding negative electrode used in the laminated polymer electrolyte battery of Example 1 of the present invention.

FIG. 3 is a cross-sectional view schematically illustrating an example of a stacked polymer electrolyte battery according to Example 1 of the present invention.

FIG. 4 is an enlarged view of a main part of a stacked electrode group in the battery shown in FIG.

5 is a cross-sectional view schematically showing a connection portion between a laminate of a lead portion of a positive electrode of the battery shown in FIG. 3 and a positive electrode terminal serving as an external terminal and the vicinity thereof.

FIG. 6 is a cross-sectional view schematically showing a connection portion between a lead body connected to a laminate of a lead portion of a positive electrode of a laminated polymer electrolyte battery according to a second embodiment of the present invention and a positive electrode terminal as an external terminal, and the vicinity thereof; It is.

FIG. 7 is a cross-sectional view schematically showing a connection portion between a laminate of a lead body of a positive electrode of a laminated polymer electrolyte battery according to a third embodiment of the present invention and a positive electrode terminal as an external terminal, and the vicinity thereof.

FIG. 8 is a cross-sectional view schematically showing a connection portion between a lead body connected to a laminate of a lead body of a positive electrode of a laminated polymer electrolyte battery according to a fourth embodiment of the present invention and a positive electrode terminal as an external terminal, and the vicinity thereof; It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Aluminum foil 1b Positive electrode mixture layer 1c Lead part 2 Negative electrode 2a Copper foil 2b Negative electrode mixture layer 2c Lead part 3 Polymer electrolyte 4 Outer body 4a Sealing part 5 Positive terminal 6 Negative terminal 7 Reinforcement plate 8 Lead body 10 Polymer electrolyte Retained positive electrode 20 Polymer electrolyte retained negative electrode

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) DJ02 DJ05 DJ07 DJ09 EJ01 HJ04 HJ12

Claims (4)

[Claims] 1. A sheet-like positive electrode having a positive electrode mixture layer formed on at least one surface of an aluminum current collector and a negative electrode mixture layer formed on at least one surface of a copper current collector. A plurality of sheet-shaped negative electrodes are laminated via a polymer electrolyte, and the laminated electrode group is packaged with a package. In the laminated polymer electrolyte battery, the lead portion of at least one of the positive electrode and the negative electrode is provided. And a laminate of the lead portion is reinforced with a reinforcing plate made of the same kind of metal as the lead portion and having a thickness of at least twice the thickness of the lead portion, and the lead reinforced with the reinforcing plate A laminate-type polymer electrolyte battery, wherein the laminate or reinforcing plate of the portion is connected to an external terminal or a lead body to the external terminal. 2. The stacked polymer electrolyte battery according to claim 1, wherein the electrode is a positive electrode. 3. The stacked polymer electrolyte battery according to claim 1, wherein said electrodes are a positive electrode and a negative electrode. 4. The laminated polymer according to claim 1, wherein the connection between the laminated body or reinforcing plate of the lead portion and the external terminal or the lead body to the external terminal is made at a sealing portion of the exterior body. Electrolyte battery.