JP2003162996A - Power storage device and lead unit used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power storage device which is easily manufactured even in a small size model and has high yield in mounting. <P>SOLUTION: This lead unit has one pair or more leads and an insulating resin body covering the region of the leads except for both end portions of the leads, for integrally supporting the leads so that the intervals between the leads are constant. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power storage device and a lead unit used therein.

[0002]

2. Description of the Related Art In recent years, electronic devices have been made smaller and lighter, and accordingly, there has been a demand for smaller and lighter electric power storage devices such as capacitors and batteries as electric power storage devices. It is getting higher.

For example, a lithium secondary battery has been put into practical use as a small-sized, light-weight and high-capacity chargeable / dischargeable battery, and portable electronic / communication devices such as small video cameras, mobile phones, and notebook computers. It is becoming widely used for such purposes.

In such a lithium secondary battery, a negative electrode plate impregnated with a carbon-based material capable of inserting and extracting lithium ions as a negative electrode active material, and L as a positive electrode active material.
A positive electrode plate impregnated with a lithium-containing metal oxide such as iNiO ₂ is laminated via a separator to form a wound body, and one end of each lead is welded to the positive electrode plate and the negative electrode plate. It is formed by accommodating a wound body in a container, filling an electrolyte solution in which a lithium salt is dissolved, and then sealing the opening of the container with a resin.

In such a lithium secondary battery, as shown in FIG. 7, when sealing the opening of a container 100 made of an outer film or the like, a pair of leads 102 are arranged at predetermined positions of the opening. A method of collectively sealing with the adhesive resin 103 is adopted. However, at the time of sealing, if the amount of heat is too large, a short circuit with the exterior film may occur, or if the amount of heat is too small, there will be insufficient adhesion, and delicate adjustment of the amount of heat is required. Was causing the decrease.

Therefore, there has been proposed a method of using a lead whose sealing region is covered with an insulating tape. That is, as shown in FIG. 8, the tape 101 made of an insulating resin.
There is proposed a lead 102 which is partially covered with.
This prevents the two leads forming the positive electrode terminal and the negative electrode terminal from being extremely close to each other in the sealing region,
This is to prevent a short circuit. Therefore, the tape is provided with a margin in order to maintain the lead interval in order to prevent a short circuit between the leads.

[0007]

However, with the miniaturization and thinning of the device, this margin has become a big problem to prevent miniaturization. Further, with the miniaturization, a pair of leads needs to be close to each other, but it is extremely difficult to perform positioning with high accuracy, and if they are brought close to each other, there is a risk of short circuit or overlapping of margins, which may result in poor sealing. Becomes higher.

As described above, according to the conventional method, it is extremely difficult to position the leads with high precision due to the miniaturization, and there is a possibility that the leads may be short-circuited or the liquid may leak due to a defective seal.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power storage device which is easy to manufacture even when miniaturized and has a high mounting yield.

[0010]

Therefore, the lead unit of the present invention is arranged in at least a pair of leads and an area excluding both ends of the leads so that the distance between the leads becomes a constant value. And an insulating resin body that integrally holds the lead.

According to this structure, the lead interval can be maintained with high accuracy, and when assembling, even if the lead-to-lead distance is narrow, the margin portions overlap each other or the margin becomes very narrow, which makes sealing difficult. It becomes possible to improve the mounting yield.

Since the lead interval is determined,
It is easy to handle and the workability of mounting is extremely good.

The insulating resin body includes a base layer and an adhesive resin layer for fixing the leads on the base layer.

According to this structure, since the lead is fixed to the base layer by using the adhesive resin layer, the lead and the insulating resin body can be easily fixed to each other, and the lead container (for the power storage device) can be easily fixed. Even when sealing (sealing) to the container, a short circuit with the container is prevented, and the yield can be improved. Here, the base layer refers to a high melting point layer or a crosslinked layer having a high molecular weight. That is, in order to maintain the insulating property, an adhesive resin layer is formed and integrated on a base layer composed of a high melting point layer or a crosslinked layer having a high molecular weight, and sealing is performed. That is, in order to maintain the insulating property, a method of using a crosslinked layer to increase the molecular weight to suppress the fluidity, and a method of providing a high melting point layer so as not to be melted by the heat at the time of sealing can be considered. At this time, the crosslinked layer is used to suppress fluidity, or the high melting point layer is used to prevent melting. Since the temperature applied at the time of sealing is the melting point of the resin layer + α, it is desirable to use a resin having a melting point higher than the melting point of the resin layer by 20 ° C. or more as the high melting point layer. For example, acid-modified random PP (melting point 140 ° C) as the adhesive layer
When is used, homo PP (melting point 160 ° C.) can be used for the insulating layer.

The insulating resin body is composed of the first and second insulating resin bodies.
And the adhesive resin layer that fixes the leads by interposing the leads between the first and second cross-linking layers.

According to this structure, since the cross-linking layers are provided on both sides of the lead, when the lead is sealed in the container (for power storage device), a short circuit with the container is more reliably prevented, and the yield is improved. Can be improved.

Further preferably, the insulating resin body contains a coloring resin.

According to this structure, the resin end face can be optically detected, and the positioning at the time of cutting or mounting can be easily automated.

Preferably, the first and second leads of the pair of leads are made of flat conductors made of different conductive materials.

According to this structure, even when using leads of different sizes, the leads can be fixed in advance with the insulating resin body, so that the mounting becomes extremely easy. Further, even leads of different conductive materials are preliminarily combined, so that wrong leads will not be erroneously mounted.

Preferably, the lead includes a plurality of pairs of leads, and the insulating resin body is cut to obtain:
It is characterized in that it is configured so that it can be used by separating one pair at a time.

According to this structure, continuous supply becomes easy even at the time of mounting, and automation becomes easy.

Further, the lead includes a plurality of insulating resin members arranged along the longitudinal direction of the lead member at intervals.
It is characterized in that it can be cut between the insulating resin bodies.

According to this structure, when the lead unit is manufactured, it is only necessary to provide the insulating resin at a predetermined interval in a state where the two leads are arranged side by side. Therefore, continuous supply becomes easy even at the time of mounting. , Automation becomes easy.

Further, the power storage device of the present invention is arranged in a region excluding both ends thereof, and is integrally held by an insulating resin body so that the mutual distance becomes a constant value. At least one lead pair including a second lead, a power storage element body having electrodes connected to one ends of the first and second leads, and the other ends of the first and second leads Including the periphery of the insulating resin body so as to be exposed to the outside as a terminal,
A container for accommodating the power storage element body is provided, and the container is sealed with a sealing resin.

According to this structure, even when the lead spacing is narrow, the margins do not overlap with each other, and the margins are not so narrow that sealing becomes very difficult.
Since the positive and negative electrode leads may be fixed in advance at a predetermined interval and then sealed, packaging is easy and the yield is high even when the size is reduced.

Preferably, the insulating resin body has a base layer,
An adhesive resin layer for fixing the first and second leads is provided on the base layer.

According to this structure, since the first and second leads are fixed to each other by the base layer and the adhesive resin layer, the positions of the container and the leads are maintained as they are during sealing (sealing). Short circuits are completely prevented, and the yield can be further improved. In order to maintain the insulating property, a cross-linking layer is used as the base layer, a method of increasing the molecular weight to suppress the fluidity, a method of providing a high melting point layer so as not to be melted by the heat when sealing the container, There is. When the cross-linked layer is used as the base layer, the fluidity is suppressed, so that the position can be maintained as it is at the time of sealing, and the short circuit between the container and the lead is completely prevented. Further, when the high melting point layer is used as the base layer, the temperature applied when the container is sealed is the melting point of the resin layer + α. Therefore, as the high melting point layer, a resin having a melting point of 20 ° C. or more higher than the melting point of the resin layer is used. It is desirable that this allows it to be held in place during sealing and completely prevents shorting of the container and the leads.

Further preferably, the insulating resin body has an adhesive resin layer for fixing the leads by interposing the leads between the first and second cross-linking layers and the first and second cross-linking layers. It is characterized by including and.

According to this structure, since the cross-linking layers on both sides of the lead are held in their positions without being softened during sealing, short-circuit between the container and the lead is completely prevented,
It is possible to further improve the yield.

Desirably, the cross-linking layer is composed of the adhesive resin and the same type of resin material.

According to this structure, since the cross-linking layer and the adhesive resin as the sealing resin are made of the same type of resin material, the adhesion between the cross-linking layer and the adhesive resin is good and the heat resistance is high. The expansion rate becomes close, the strain is reduced, and the yield can be further improved.

Preferably, the insulating resin body contains a colored resin.

With this structure, the resin end face can be optically detected, and the positioning at the time of cutting or mounting can be easily automated.

Preferably, the first and second leads are made of different conductive materials.

According to this structure, even if the leads of different sizes are used, the leads can be fixed in advance with the insulating resin body, so that the mounting becomes extremely easy.

Further, it is preferable that the container is constructed so as to have the same electric potential as one of the first and second leads.

When the container is constructed so as to have the same potential as one of the first and second leads, if the container and the other lead are short-circuited, a defective product is produced and the yield is lowered. For example, since the lead interval is secured by the insulating resin body, it is possible to prevent a decrease in yield.

Preferably, the container is made of a flexible film.

Further, when the container is made of a flexible film, a short circuit is likely to occur particularly in the sealing region, but the yield between the first and second leads is maintained with high accuracy. Can be prevented.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment Hereinafter, a lead unit according to a first embodiment of the present invention will be described. As shown in FIGS. 1 (a) and 1 (b), this lead unit has a length L1 = 15 to 60 mm, a width W3 = 2 to 10 mm, and a thickness t = 0.05 to 2.0 mm, which is made of aluminum. First lead 1a made of a conductor
And a pair of lead pairs consisting of a second lead 1b made of a rectangular conductor made of nickel and a region excluding both ends of the leads, and the distance W2 between the leads is 2
the first and second leads 1 so as to be about mm.
It is characterized by comprising an insulating resin body T having a width W1 = 7 to 35 mm and a length L1 = 5 to 10 mm, which are integrally held so as to define mutual positions of a and 1b.

This insulating resin body T comprises first and second tapes 2a and 2b made of polypropylene which are cross-linked by irradiation.
And the adhesive resin layer 3 made of modified polypropylene for fixing the first and second leads, which is interposed between them.

At the time of production, adhesive tapes 3a and 2b made of polyethylene cross-linked by irradiation were thermocompression-bonded and laminated on opposite surfaces,
The first and second leads are placed on the adhesive resin agent surface of one tape, and the adhesive resin layer surface of the other tape is placed inside, and further thermocompression bonded and fixed.

According to this lead unit, the lead interval can be maintained with high accuracy, and the mounting yield can be improved at the time of assembly. Further, since the lead interval is determined, it is easy to handle and the workability of mounting is extremely good.

Next, an example in which this lead unit is used for mounting a lithium secondary battery will be described. As shown in FIGS. 2 (a) and 2 (b), this lithium secondary battery has the other ends of the first and second leads 1a and 1b of the lead unit shown in FIGS. 1 (a) and 1 (b). So as to be exposed to the outside as a connection terminal, the container 4 made of an exterior film for accommodating the battery body with the insulating resin body.
And is sealed in the container 4 with a sealing resin. Here, the container 4 has a three-layer structure of biaxially stretched nylon, an aluminum foil, and an adhesive layer 5, and as the adhesive layer 5, a heat-modified random polypropylene resin is used.

Here, a negative electrode plate 6a formed by impregnating a porous core body with a carbon-based material capable of absorbing and desorbing lithium ions as a negative electrode active material, and a porous core body containing a lithium-containing metal as a positive electrode active material. A positive electrode plate 6b impregnated with an oxide is laminated via a separator 7, and the laminated body is wound to form a wound body, and then the positive electrode plate 6a and the negative electrode plate 6b are formed.
One end of each of the leads 1a and 1b is welded to each of the above, and the wound body is housed in an outer container 4 made of a flexible outer film made of a two-layer structure of biaxially stretched nylon and aluminum foil, and lithium salt is added. It is formed by filling a dissolved electrolytic solution (not shown) and sealing the mounting area of the insulating resin body T in the opening of the container through the acid-modified random polypropylene resin 5.

According to such a lithium secondary battery, the polypropylene tapes 2a, 2 whose lead pairs are cross-linked layers are used.
Since the adhesives made of acid-modified random polypropylene resin are fixed between the parts b, the leads are not displaced from each other during the encapsulation, and it is possible to easily carry out highly reliable mounting.

When sealing the opening of the container 4 made of an outer film, a lead unit is placed in the opening and acid-modified random PP (polypropylene resin) 5 is used.
It is heated to 160 ° C. and sealed. Even if the tape is sealed at 160 ° C. here, the tape is melted only for a short time, and the tape is not melted over the entire area.

In this way, 50 lithium secondary batteries were produced and the cross section of the sealed portion of the lithium secondary battery was measured. The results are shown in Table A below. Also, for comparison, lithium was formed in the same manner except that an acid-modified random polypropylene resin (melting point 140 ° C.) 5 was used instead of the polypropylene tapes 2a and 2b when the lead pairs were bonded and sealed. The cross section of the sealed portion of the secondary battery was measured. The results are shown in Table B below.

Further, the cross section of the sealed portion of the lithium secondary battery formed by combining one conventional lead shown in FIG. 7 was measured. The results are shown in Table C below.

[0051]

[Table 1]

As is clear from the above results, according to this embodiment, the defective rate was 0, and good assembly results could be obtained.

According to this embodiment, the lead pairs are insulated and fixed to each other by the insulating resin body even when performing the collective sealing, and the tape is not deformed by the heat in the sealing process. It is thought that the pair can be firmly held.

When the sealing resin for fixing the inner surface of the exterior film forming the container and the tape are the same, a short circuit occurs with the exterior film. It is considered that this is because the tape was melted by the heat in the sealing process.

Furthermore, in the case of the conventional example in which leads are combined one by one, it is considered that the resin of the lead wires overlapped with each other in the sealing step and a sealing failure occurred.

Thus, according to the embodiment of the present invention,
In the sealing step, the margins do not overlap with each other or a gap is formed between the margins so that the margins cannot be completely filled and the adhesion does not become insufficient. Therefore, good sealing can be achieved very easily with good workability, and the manufacturing yield can be improved.

Further, even when the lead spacing is narrow, the spacing can be maintained with high accuracy, and mounting is easy and the yield is high even when the size is reduced. In addition, the presence of the tape can prevent a short circuit with the outer container due to heat during use.

In the above-mentioned embodiment, the insulating resin body is composed of a transparent polypropylene resin tape which is cross-linked by irradiation, but it is composed of a polypropylene tape to which carbon or the like is added so that coloring such as black is added. Good.

According to this structure, since the tape is colored, the presence region of the insulating resin body can be easily detected by the sensor even when the automatic mounting is performed, and the automatic mounting is facilitated.

The first and second leads are preferably made of aluminum or the like for use as the positive electrode terminal, and copper, nickel, nickel-plated copper, or the like for use as the negative electrode terminal.
It is desirable to use a rectangular conductor such as aluminum. Also, the first and second leads may be different materials,
You may comprise with the same material.

Embodiment 2 Next, a second embodiment of the present invention will be described.

In this example, as shown in FIG. 3, the lead unit includes a plurality of pairs of leads 1a and 1b, and by cutting the insulating resin body, one lead pair U is formed.
1, U2, U3 ... Are individually configured to be cut.

The individual lead pairs are formed in the same manner as described in the first embodiment. If necessary, a groove for facilitating the cutting may be formed in the cutting region of the insulating resin body.

According to such a structure, in addition to the effect of the first embodiment, it is possible to form them all at once, and it becomes easy to carry them.

Third Embodiment In addition, in the second embodiment, the leads are provided at equal intervals, but in this embodiment, as shown in FIG. 4, one lead is provided in an area corresponding to the unit. It is formed so that the interval is increased by about a minute. According to this lead unit, when mounting on a power storage device, etc., it is possible to mount it as an integrated state without cutting the insulating resin body and separate it individually, and finally divide it. Therefore, it is possible to easily obtain a highly reliable battery.

Next, a method of manufacturing a lithium battery using this lead unit will be described.

That is, the insulating resin body is not cut into individual pieces but is mounted in an integrated state, and one end of the lead of each lead unit is welded to each electrode body.

Then, as shown in FIG. 5 (a), after being integrally covered with a sheet-shaped exterior film (exterior container) 4, the boundary portion is fused by heat to be divided into individual regions.
After this, the electrolytic solution is filled, and as shown in FIG. 5 (b), the opening of the outer container is heat-sealed and collectively sealed. Finally, as shown in FIG. 5C, the individual batteries are separated.

As described above, the lead units in which a large number of lead pairs are arranged side by side are collectively mounted and sealed, and finally cut and separated, whereby the assembly can be performed with extremely high workability. Further, when mounting, continuous supply becomes easy, and automation becomes easy.

Fourth Embodiment In addition, in the second and third embodiments, the case where the lead units are continuously formed in parallel has been described, but in this embodiment, as shown in FIG. The lead pair composed of the second leads 1a and 1b includes a plurality of insulating resin bodies T arranged along the longitudinal direction of the lead pair so as to be separated from each other.
It is characterized in that it includes 1, 1, T2 ... And can be cut between insulating resin bodies.

According to this structure, when the lead unit is manufactured, it is only necessary to provide the insulating resin at a predetermined interval in a state where the two leads are arranged side by side. Therefore, continuous supply is facilitated even at the time of mounting. , Automation becomes easy.

When mounting on a device, workability is good if it is used in the state of being cut into pairs as in the case of the second embodiment.

Although the lithium secondary battery has been described in the above embodiment, the present invention is not limited to this.
It is also applicable to batteries such as alkaline batteries such as Ni-MH batteries, or other power storage devices such as capacitors.

In the above embodiment, the acid-modified polypropylene resin is used as the adhesive resin, but the adhesive resin is not limited to this, and polyethylene, acid-modified polyethylene, ionomer or the like can be used. Furthermore,
Also for the cross-linked layer, acid-modified polypropylene resin, polyethylene or acid-modified polyethylene, ionomer and the like can be used. Further, it is desirable that the adhesive resin and the crosslinked layer use the same type of resin.

[0075]

As described above, according to the lead unit of the present invention, it is arranged in at least the pair of leads and the area excluding both ends of the leads, and the distance between the leads becomes a constant value. As described above, since the insulating resin body that integrally holds the leads is provided, the lead interval can be maintained with high accuracy, and the margin portions overlap each other during assembly even when the lead-to-lead distance is narrow. Or
The margin becomes extremely narrow, the problem of difficulty in sealing is eliminated, and the mounting yield can be improved. Further, since the lead interval is determined, it is easy to handle and the workability of mounting is extremely good.

[Brief description of drawings]

FIG. 1 is a diagram showing a lead unit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a lithium secondary battery formed by using the lead unit according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a lead unit according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a lead unit according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a mounting process of a lithium secondary battery using the lead unit according to the third embodiment of the present invention.

FIG. 6 is a diagram showing a lead unit according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a conventional battery.

FIG. 8 is a view showing a conventional lead unit.

[Explanation of symbols]

1a 1st lead 1b Second lead 2a tape 2b tape 3 Adhesive resin layer 4 containers 5a Adhesive resin layer 6a Positive plate 6b negative electrode plate 7 separator U1, U2, U3 ... Lead unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiichi Tanaka             Sumitomo Electric 3-3 Satsukicho, Kanuma City, Tochigi Prefecture             Kanto Manufacturing Co., Ltd. F-term (reference) 5H011 AA03 AA09 CC02 CC06 CC10                       DD13 DD14 DD22 EE04 FF04                       GG04 GG08 HH00 HH02 HH11                       HH19 KK01                 5H022 BB02 BB03 BB05 BB12 BB24                       CC03 CC27 EE06 EE10 KK03

Claims (15)

[Claims] 1. At least a pair of leads, and the leads are arranged in an area excluding both ends of the leads, and the leads are held in parallel and integrally so that a distance between the leads becomes a constant value. A lead unit comprising an insulating resin body. 2. The lead unit according to claim 1, wherein the insulating resin body includes a base layer and an adhesive resin layer for fixing the leads on the base layer. 3. The insulating resin body includes first and second cross-linking layers, and an adhesive resin layer that fixes the leads by interposing the leads between the first and second cross-linking layers. The lead unit according to claim 1, wherein: 4. The lead unit according to claim 1, wherein the insulating resin body contains a colored resin. 5. The lead unit according to claim 1, wherein the first and second leads forming the pair of leads are made of different conductive materials. 6. The lead includes a plurality of pairs of leads, and is configured such that by cutting the insulating resin body, the leads can be separated and used one by one. Lead unit according to any one of. 7. The lead includes a plurality of insulating resin bodies that are spaced apart from each other along a longitudinal direction of the lead, and is configured to be cut between the insulating resin bodies. Item 6. The lead unit according to any one of items 1 to 5. 8. At least one of a first lead and a second lead, which are arranged in a region excluding both ends and integrally held by an insulating resin body so that a mutual distance has a constant value. One lead pair, a power storage element body having electrodes connected to one ends of the first and second leads, respectively, and the other ends of the first and second leads being exposed to the outside as connection terminals. A container for accommodating the power storage element main body, including a periphery of the insulating resin body, and being sealed in the container by a sealing resin. 9. The power storage device according to claim 8, wherein the insulating resin body includes a base layer and an adhesive resin layer for fixing the first and second leads on the base layer. device. 10. The insulating resin body includes first and second cross-linking layers, and an adhesive resin layer for fixing the leads by interposing the leads between the first and second cross-linking layers. The power storage device according to claim 8, wherein the power storage device is a storage device. 11. The power storage device according to claim 9, wherein the cross-linking layer is made of a resin material of the same system as the adhesive resin. 12. The power storage device according to claim 8, wherein the insulating resin body contains a colored resin. 13. The first and second leads are made of conductive materials different from each other.
13. The power storage device according to any one of 1 to 12. 14. The power storage device according to claim 8, wherein the container is configured to have the same potential as one of the first and second leads. 15. The power storage device according to claim 8, wherein the container is made of a flexible film.