JP2003257411A - Non-aqueous electrolyte battery - Google Patents

Abstract

(57) [Problem] To provide a non-aqueous electrolyte battery having a configuration in which an external connection lead made of nickel can be connected to a battery case or a sealing plate by resistance welding without any trouble when configuring a battery module or a battery pack. I do. A bottomed tubular aluminum battery case is provided.
The electrode group 12 is housed therein, and an organic electrolyte is injected, and the opening of the battery case 11 is sealed with an aluminum sealing plate 13. The outer surface of at least one of the battery case 11 and the sealing plate 13 is subjected to a surface treatment to obtain nickel, iron,
Metal thin film layers 14, 17 using at least one of chromium, gold, silver, and copper are formed as connection terminals. The metal thin film layers 14, 17 are formed by either an electroless plating method or a metal evaporation method. Metal thin film layer 14
Is a battery case 1 having a bottomed cylindrical shape after the can manufacturing process is completed.
1 is locally formed only at the center of the outer surface of the bottom plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte (organic solvent electrolyte) battery represented by a lithium-ion secondary battery, which is a sealed battery having a small capacity and a large capacity. More specifically, the present invention relates to a non-aqueous electrolyte battery having a structure suitable for a battery module or a battery pack.

[0002]

2. Description of the Related Art In recent years, portable and cordless AV equipment or electric equipment such as personal computers and portable communication equipment have been rapidly promoted. Conventionally, aqueous solution batteries such as nickel-cadmium batteries and nickel-hydrogen batteries have been mainly used as driving power sources for these electric devices, but in recent years, particularly, rapid charging is possible and the energy density is high and high. Non-aqueous electrolyte secondary batteries typified by lithium-ion secondary batteries having safety are becoming mainstream. In this non-aqueous electrolyte secondary battery, it has been promoted that the sealed type is excellent in high energy density and load characteristics, and that the prismatic shape is suitable for thinning the device and has a high space utilization effect.

Further, in the above-mentioned non-aqueous electrolyte secondary battery, further miniaturization and weight reduction are demanded, so that the battery case and the sealing plate are made of a metal which is relatively lightweight and suitable for thinning. It is formed by using aluminum or aluminum alloy as a material. Apart from this, in recent years,
A plurality of arranged non-aqueous electrolyte batteries are electrically connected in series or in parallel and mechanically connected to each other for the purpose of obtaining the required power as a power source for driving an electric power tool, a personal computer or a mobile phone. Thus, a battery module or a battery pack is constructed.

A conventional inter-battery connecting structure for constructing the above-mentioned battery module or battery pack has a structure as shown in FIG. In the plurality of non-aqueous electrolyte secondary batteries Ba1 and Ba2 connected to each other, the battery case 1 serving as the positive electrode and the sealing plate 2 are both made of aluminum as described above, and constitute the negative electrode. The negative electrode terminal 3 is made of a rivet made of nickel plated with iron. The external connection lead 4 for connecting the batteries Ba1 and Ba2 is generally made of nickel, which has a good corrosion resistance to an organic electrolyte and has a low electric resistance.

It is difficult to join the nickel external connection lead 4 to the aluminum battery case 1 or the sealing plate 2 by welding or the like because the melting temperature of nickel is much higher than that of aluminum. . Therefore, conventionally, the positive electrode terminal 7 for connecting the external connection lead 4 is provided by welding on the outer surface of the bottom plate portion of the battery case 1. As the positive electrode terminal 7, a clad material in which a joining layer 7a made of aluminum and a connection layer 7b made of nickel are joined is used. The positive electrode terminal 7 is attached by joining a joining layer 7a made of aluminum to the bottom surface of the battery case 1 made of the same metal as the positive terminal 7, and the external connection lead 4 made of nickel is welded to the connection layer 7b made of the same metal. Are joined and connected by.

[0006]

However, when the positive electrode terminal 7 made of a clad material is joined to the battery case 1 by welding, there is a drawback that burrs and uneven surfaces are generated on the inner surface of the bottom plate portion of the battery case 1. is there. That is, since the joining layer 7a of the positive electrode terminal 7 is formed of aluminum, the joining layer 7a cannot be resistance-welded to the battery case 1 made of aluminum of the same metal as the joining layer 7a.
Therefore, the positive electrode terminal 7 is joined to the outer surface of the bottom plate portion of the battery case 1 by laser welding or ultrasonic welding.

However, in the case of joining by laser welding, the positive electrode terminal 7 and the battery case 1 at the time of welding are connected to each other as shown in FIG. The nugget 8 generated by melting may become large, and a flash 9 may be formed on the inner surface side of the bottom plate portion of the battery case 1. On the other hand, when the positive electrode terminal 7 is joined to the outer surface of the bottom plate portion of the battery case 1 by ultrasonic welding, the uneven surface 10 as the pressure contact mark of the ultrasonic transducer is formed in the battery case as shown in FIG. 1 may be formed on the inner surface side of the bottom plate portion. Such burrs 9 and uneven surfaces 10 may damage the spiral electrode group inserted in the battery case 1. In particular, when the separator is damaged, the positive and negative plates contact each other. Can easily cause an internal short circuit.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and when a battery module or a battery pack is constructed, the external connection lead made of nickel is connected to the battery case or the sealing plate by resistance welding without any trouble. It is an object of the present invention to provide a non-aqueous electrolyte battery having a constitution that can be performed.

[0009]

In order to achieve the above object, the present invention provides an opening of the battery case in which an electrode group is housed in a bottomed cylindrical battery case made of aluminum and an organic electrolyte is injected. In a non-aqueous electrolyte battery part of which is sealed with an aluminum sealing plate, the outer surface of at least one of the battery case or the sealing plate is subjected to a surface treatment, nickel, iron, chromium, gold, silver and copper. The metal thin film layer using at least one of the above is formed as a connection terminal.

When a plurality of non-aqueous electrolyte batteries are connected to form a battery module or battery pack,
A commonly used nickel external connection lead can be joined to the metal thin film layer by resistance welding for connection. Therefore, when the metal thin film layer is provided on the battery case, burrs and uneven surfaces do not occur on the inner surface side of the battery case, so that the electrode group housed in the battery case is not damaged and the electrode group of the electrode group is not damaged. The occurrence of an internal short circuit due to the contact between the positive and negative plates is reliably prevented.

In the above invention, the metal thin film layer is preferably formed by an electroless plating method. As a result, in the prismatic battery, the metal thin film layer made of nickel having a high melting temperature can be formed on the battery case or the sealing plate which is generally made of aluminum as a material without any trouble. In addition, since the metal thin film layer is formed of an alloy, it has good adhesion to the battery case or the sealing plate, excellent corrosion resistance and abrasion resistance, and high uniformity. . Further, in the electroless plating method, a metal thin film layer having a plating thickness arbitrarily selected and set can be obtained with high accuracy.

Further, in the above invention, the metal thin film layer can be formed by a vacuum deposition method, and in this case also,
It is possible to obtain almost the same effect as the electroless plating method.

Further, the metal thin film layer in the above invention is 5 to
It is preferably formed to a thickness of 30 μm. Thereby, a metal thin film layer having a required function can be obtained at low cost. That is, when the thickness is 5 μm or less, the metal thin film layer is too thin to perform resistance welding, and the thickness is 3
When the thickness is 0 μm or more, not only the plating takes time, but also the amount of plating material used increases and the material cost increases.

Further, the metal thin film layer in the above invention is
It is preferable that the battery case is formed locally only at the central portion of the outer surface of the bottom plate portion of the battery case having a bottomed tubular shape after the can making process is completed. According to this structure, the amount of relatively expensive nickel or gold used is reduced as much as possible, and the metal thin film layer that can reliably obtain the required function as the connection terminal is obtained while the structure is inexpensive. Can be formed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Figure 1 (a)
[FIG. 3] is a vertical cross-sectional view showing a non-aqueous electrolyte battery Ba according to an embodiment of the present invention, and (b) is a bottom view of the battery. In the figure, a prismatic lithium secondary battery, which is one of typical non-aqueous electrolyte batteries Ba, is illustrated. This non-aqueous electrolyte battery B
As is clear from (b), a indicates that the rectangular spiral electrode group 12 is housed in a battery case 11 having a rectangular prism shape with a flat cross section, and the opening of the battery case 11 is sealed. It is sealed by the plate 13.

The battery case 11 and the sealing plate 13 are made of aluminum as in the existing one, but the difference from the existing one is that the outer surface of the bottom plate portion of the battery case 11 and the outer surface of the sealing plate 13 are different. The thin metal thin film layers 14 and 17 are respectively formed by subjecting the surface treatment to the surface treatment. Although only one of the metal thin film layers 14 and 17 may be formed, the embodiment exemplifies a case where both of the metal thin film layers 14 and 17 are formed for convenience of description.

The metal thin film layers 14 and 17 serve as connection terminals for connecting the external connection leads 4 shown in FIG. 4 when forming a battery module or a battery pack. Therefore, the metal thin film layer 14 of the battery case 11 is locally formed only on the central portion of the outer surface of the bottom plate portion to which the external connection lead 4 is connected. Since the sealing plate 13 is provided with a recess 19, a liquid injection hole 13a, and a safety valve hole portion 13b, which will be described later, the case where the metal thin film layer 17 is formed on the entire outer surface is shown as an example. Alternatively, the metal thin film layer 17 may be locally formed at a place to be a connection terminal. Details of the metal thin film layers 14 and 17 will be described later.

The frame 18 is fitted in a position near the opening of the battery case 11, and the sealing plate 13 is welded to the peripheral edge of the opening of the battery case 11 while being placed on the frame 18 so that the battery case 11 is closed. The opening is sealed. An upper insulating gasket 20 is fitted in a recess 19 in the center of the sealing plate 13, and a negative electrode terminal 21 made of a nickel-plated iron rivet is inserted into the sealing plate 13 via the upper insulating gasket 20. On the other hand, it is inserted into the insertion holes of the upper insulating gasket 20 and the sealing plate 13 while being electrically insulated.

The lower portion of the negative electrode terminal 21 into which the upper insulating gasket 20 and the sealing plate 13 are inserted is further inserted into the respective mounting holes of the lower insulating gasket 22 and the negative electrode terminal plate 23, and then the lower ends thereof are caulked. It is processed. Thereby, the negative electrode terminal plate 23
Is electrically insulated from the sealing plate 13 through the lower insulating gasket 22, and is electrically connected to the negative electrode terminal 21 through the caulked portion of the negative electrode terminal 21.

The negative electrode lead 24 and the positive electrode lead 27 led out from the rectangular spiral electrode group 12 are respectively provided in the frame body 18.
Through the insertion holes 18a, 18b of the positive electrode lead 27
Of the negative electrode lead 24 is welded to the inner surface of the sealing plate 13, and the distal end of the negative electrode lead 24 is welded to the negative electrode terminal plate 23.

When assembling the non-aqueous electrolyte battery Ba, the upper insulating gasket 20, the lower insulating gasket 22 and the negative electrode terminal plate 23 are connected to the negative electrode terminal 21.
After each of them is attached, the sealing plate 13 is fitted into the opening of the battery case 11 and welded. After that, an organic electrolytic solution (not shown) is injected into the battery case 11 through the liquid injection hole 13a of the sealing plate 13. The liquid injection hole 13a is closed by a sealing plug 28 after the injection of the electrolytic solution.

Further, the sealing plate 13 has a safety valve hole portion 13b formed at a position opposite to the liquid injection hole 13a.
The safety valve hole 13b is closed by an aluminum thin film 29 attached to the lower surface of the sealing plate 13 by a clad method. The portion of the aluminum thin film 29 that closes the safety valve hole 13b increases in battery internal pressure. A safety valve 29a for breaking the gas and releasing the gas to the outside is constructed. In this embodiment, the metal thin film layer 17 of the sealing plate 13 is the liquid injection hole 13 on the outer surface of the sealing plate 13.
a, the safety valve hole 13b and the recess 19 are formed on the entire surface. In this non-aqueous electrolyte battery Ba, the metal thin film layer 1 described above in the battery case 11 or the sealing plate 13 is used.
Reference numerals 4 and 17 are positive electrodes, and the negative electrode terminal 21 made of a rivet is a negative electrode.

Next, the metal thin film layers 14 and 17 provided on the outer surface of the bottom plate portion of the battery case 11 and the outer surface of the sealing plate 13 will be described. This metal thin film layer 14,
Reference numeral 17 is a connection terminal for connecting an external connection lead when a plurality of the non-aqueous electrolyte batteries Ba are connected to form a battery module or a battery pack. As the external connection leads, those formed of nickel as a material are generally used, and in this embodiment, the metal thin film layers 14 and 17 are made of nickel of the same metal as the external connection leads. Is forming. However, the metal thin film layers 14 and 17 are not limited to nickel, but may be formed using iron, chromium, gold, silver, copper, or an alloy selected from these alloys.

Further, in this embodiment, the metal thin film layer 1
4, 17 are formed by electroless plating. The metal thin film layer 14 is formed on the outer surface of the bottom plate portion of the battery case 11 having a bottomed rectangular tube shape after the can making process is completed. The outer surface of the bottom plate portion of the battery case 11 thus manufactured is first subjected to cleaning, degreasing and etching with an alkaline solution in a pretreatment process to remove the oxide film on the surface. The outer surface of the bottom plate portion, which has been subjected to the pretreatment, is covered with a masking material made of an insulating material such as an adhesive tape, for example, at a portion except a portion where the metal thin film layer 14 is to be formed, and is masked.

Subsequently, the masked outer surface of the bottom plate portion of the battery case 11 is brought into contact with a plating solution containing nickel nitrate or nickel sulfate as a main component. As a result, dehydrogenative decomposition occurs using aluminum, which is the material to be plated, of the battery case 11 as a catalyst, and the generated hydrogen atoms are adsorbed on the surface of the catalytic metal (in this case, the aluminum of the battery case 11). So-called Condensed Layer
Then, it is activated, and when it comes into contact with nickel cations in the plating solution, nickel is reduced to metal and deposited on the surface of the catalyst metal. The activated hydrogen atoms on the surface of the catalyst metal react with the hypophosphorous anion in the plating solution to reduce the phosphorus contained therein to form an alloy with nickel. The nickel thus deposited serves as a catalyst to continue the same nickel reduction plating reaction as described above. That is, the plating continues to proceed due to the autocatalytic action of nickel. As a result, a metal thin film layer 14 made of a nickel alloy is formed on the outer surface of the bottom plate portion of the battery case 11 which is not masked.

By employing the electroless plating method as described above, the metal thin film layer 14 made of nickel having a high melting temperature can be locally formed on the outer surface of the bottom plate of the aluminum battery case 11 without any trouble. . In addition, the metal thin film layer 14 formed of the alloy has good adhesion to the aluminum battery case 11, excellent corrosion resistance and abrasion resistance, and high uniformity. Further, in the above electroless plating method, the metal thin film layer 14 having a plating thickness arbitrarily selected and set can be obtained with high accuracy. In this embodiment, the thickness of the metal thin film layer 14 is set to 5 to 30 μm in response to the commonly used nickel external connection lead having a thickness of 0.1 mm. When the thickness is 5 μm or less, the metal thin film layer is too thin to perform resistance welding, and when the thickness is 30 μm or more, plating takes time. Not only that, but the amount of plating material used increases and the material cost increases. In addition,
In this case, the battery case 11 has a thickness of 0.2 to 0.3 mm.
Is.

Since the metal thin film layer 14 of the battery case 11 is formed as a nickel-plated layer by the above-mentioned electroless plating method on the battery case 11 which has been subjected to the can making process, it is locally formed only on the necessary central portion on the outer surface of the bottom plate portion. Can be formed with high precision, the amount of relatively expensive nickel used can be reduced as much as possible, and an inexpensive structure can be obtained.

For example, as another means for forming the metal thin film layer 14 described above, nickel plating is performed in advance on a required portion of the base material for forming the battery case 11, and the battery case 11 is subjected to DI processing by using the base material. A method of making cans is considered. However, when this method is adopted, it is necessary to locally perform nickel plating only on a predetermined portion of the outer surface of the bottom plate portion after the can is formed on the forming base material, so that the location of the portion to be plated should be determined. It will be extremely difficult. Therefore, if nickel plating is applied to the entire surface of the forming base material, the amount of expensive nickel used increases and the cost increases.

On the other hand, a method in which a nickel foil or the like is pressed against the base material for forming the battery case 11 in advance to form a clad and then a can is manufactured, but the same problem as in the case of performing the nickel plating in advance occurs. That is, when the entire surface is clad, the cost becomes high, and when locally clad, the layout of the molding position and the positioning of the clad position are required, which causes a problem that the process becomes complicated. .

The metal thin film layer 17 of the sealing plate 13 can be formed without any trouble by using the same means as the formation of the metal thin film layer 14 on the battery case 11 except for masking. It goes without saying that the timing of forming the metal thin film layer 17 in that case is after the fabrication of the sealing plate 13 is completed and before the assembly as the battery Ba.

Further, the metal thin film layers 14 and 17 can be formed without any problem even if a well-known vacuum vapor deposition method is adopted instead of the above-mentioned electroless plating method as in the case of the electroless plating method. it can. Furthermore, the metal thin film layers 14 and 1
7 can also be formed by a metal spraying method. However, it is most preferable to form the metal thin film layers 14 and 17 by the electroless plating method.

Next, the inter-battery connection structure when a plurality of the non-aqueous electrolyte batteries Ba are connected to form a battery module or a battery pack will be described. As shown in FIG. 2, the non-aqueous electrolyte batteries Ba are arranged in parallel so that the electrodes adjacent to each other are positive and negative, and the metal thin film layer 14 and the negative electrode terminal 21 of the adjacent battery cases 11 of the batteries Ba have nickel. The external connection leads 4 made of metal are laid over, and the external connection leads 4, the metal thin film layer 14, the external connection leads 4 and the negative electrode terminal 21 are welded to each other by the welding electrodes 30, 3 shown in FIG.
They are joined to each other by resistance welding using No. 1 and electrically connected. In FIG. 2, two adjacent non-aqueous electrolyte batteries B
The case where a and Ba are connected in series is illustrated.

In the inter-battery connection structure, one end of the nickel external connection lead 4 is joined by resistance welding to the negative electrode terminal 21 made of iron plated with nickel as in the conventional case. Further, since the other end of the external connection lead 4 is joined to the metal thin film layer 14 made of a nickel plating layer which serves as a positive electrode side connection terminal of the non-aqueous electrolyte battery Ba, resistance welding can be adopted as the joining means. Becomes Therefore, burrs and uneven surfaces do not occur on the inner surface of the bottom plate portion of the battery case 11 after welding. On the other hand, in the conventional inter-battery connection structure, since the welding layer 7a made of aluminum of the positive electrode terminal 7 and the battery case 11 made of aluminum cannot be resistance-welded, laser welding or ultrasonic welding is continuously performed. As a result, flash 9 and uneven surface 1
0 has occurred. Therefore, the above non-aqueous electrolyte battery B
Since a does not damage the spiral electrode group in the battery case 11 even when the external connection lead 4 is connected, the occurrence of an internal short circuit due to contact between the positive and negative electrode plates is reliably prevented. It

Further, in the non-aqueous electrolyte battery Ba, since the metal thin film layer 17 functioning as the positive electrode side connecting terminal is also formed on the outer surface of the sealing plate 13, the interelectrode connecting structure as shown in FIG. 3 is obtained. You can also do it. In this inter-electrode connection structure, a plurality of non-aqueous electrolyte batteries Ba are arranged in parallel so that adjacent electrodes have the same positive and negative polarities, and the metal thin film layer 17 of the sealing plate 13 adjacent to the batteries Ba and the negative electrode terminal are arranged. The external connection lead 4 made of nickel is bridged over the electrode 21, and the external connection lead 4 and the metal thin film layer 17, and the external connection lead 4 and the negative electrode terminal 21 are joined to each other by resistance welding and electrically connected. The non-aqueous electrolyte battery Ba used in this battery connection structure is a battery case 11
The metal thin film layer 14 is not formed on the outer surface of the bottom plate portion. That is, the metal thin film layers 14 and 17 shown in the embodiment are
It is sufficient if at least one of them is formed.

The metal thin film layer 14 of the battery case 11
Is good as a positive electrode when the non-aqueous electrolyte battery Ba is used as a unit cell, in addition to being used as a positive electrode side connection terminal for connecting the external connection lead 4 when configuring the above-mentioned inter-battery connection structure. Can be used for The metal thin film layer 14 used as the positive electrode is preferably formed of a gold plating layer instead of the nickel plating layer, because the contact resistance can be further reduced. The metal thin film layer 14 made of the gold plating layer may be formed to have a thickness of 2 to 10 μm.

[0036]

As described above, according to the non-aqueous electrolyte battery of the present invention, when a plurality of the non-aqueous electrolyte batteries are connected to form a battery module or a battery pack, nickel-made external connection is generally used. The lead is nickel, iron, chrome,
It can be joined and connected by resistance welding to a metal thin film layer using at least one of gold, silver and copper. Therefore, when the metal thin film layer is provided on the battery case, burrs and uneven surfaces do not occur on the inner surface side of the battery case, so that the electrode group housed in the battery case is not damaged and the electrode group of the electrode group is not damaged. The occurrence of an internal short circuit due to the contact between the positive and negative plates is reliably prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a non-aqueous electrolyte battery according to an embodiment of the present invention, (b) is a bottom view of the battery.

FIG. 2 is a side view showing an example of an inter-battery connection structure in the case of configuring a battery module or a battery pack by using a plurality of the above non-aqueous electrolyte batteries.

FIG. 3 is a side view showing another example of the inter-battery connection structure by the above non-aqueous electrolyte battery.

FIG. 4 is a schematic side view showing a battery connection structure in which a plurality of conventional non-aqueous electrolyte batteries are connected to each other.

FIG. 5 is a vertical cross-sectional view of a part of the battery case of the above non-aqueous electrolyte battery, wherein (a) and (b) respectively show the positive electrode terminal on the outer surface of the bottom plate portion of the battery case by laser welding and ultrasonic welding. Shows the joined state.

[Explanation of symbols]

11 battery case 12 Square spiral electrode group (electrode group) 13 Seal plate 14,17 Metal thin film layer Ba non-aqueous electrolyte battery

Continued front page    (72) Inventor Yoshio Goda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5H011 AA13 CC06 FF02 HH08 KK01                 5H022 AA09 BB22 CC02 CC09 EE01                       EE03                 5H029 AJ12 BJ02 BJ14 CJ24 DJ02                       DJ03 DJ05 EJ01 HJ04 HJ12

Claims (5)

[Claims] 1. A non-aqueous electrolyte battery in which an electrode group is housed in a bottomed cylindrical aluminum battery case, an organic electrolytic solution is injected, and the opening of the battery case is sealed with an aluminum sealing plate. In, at least one of the outer surface of the battery case or the sealing plate, subjected to a surface treatment, nickel, iron, chromium,
A non-aqueous electrolyte battery, wherein a metal thin film layer using at least one of gold, silver and copper is formed as a connection terminal. 2. The non-aqueous electrolyte battery according to claim 1, wherein the metal thin film layer is formed by an electroless plating method. 3. The non-aqueous electrolyte battery according to claim 1, wherein the metal thin film layer is formed by a vacuum deposition method. 4. The non-aqueous electrolyte battery according to claim 1, wherein the metal thin film layer is formed to have a thickness of 5 to 30 μm. 5. The metal thin film layer is locally formed only on the central portion of the outer surface of the bottom plate portion of the battery case which has a bottomed tubular shape after the can making process is completed. 5. The non-aqueous electrolyte battery according to any one of 4 to 4.