JP2002270147A - Battery assembling body and unit cell, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a unit battery at a low cost, and to decrease electric resistance value between cells, in the unit battery wherein plural unit cells connected in series are unseparably connected and fixed. SOLUTION: A unit cell 1 includes a metallic battery case 2, a generating element stored in the battery case 2, and a metallic sealing plate 3 blocking an opening of the battery case 2. A positive electrode terminal 8 on an outer surface of the sealing plate 3 and a negative electrode terminal 9 of an outer surface of the adjacent battery case 2 are welded in advance, thereby forming a battery assembling body 14. Plural battery assembling bodies 14 incorporating the generating elements are stacked in multiple stage, and each battery case 2 is sealed to make a unit cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit battery in which a plurality of batteries connected in series are fixed inseparably.

[0002]

2. Description of the Related Art In a unit battery of this type, as shown in FIG. 7, for example, adjacent button-shaped unit batteries 30 are stacked and connected in a multistage manner via a round plate-shaped connection fitting 31. . Specifically, the bottom wall of the connection fitting 31 is welded to the sealing plate (positive terminal) 32 of the lower unit battery 30, and the peripheral wall of the battery case (negative terminal) 33 of the upper unit battery 30 and the corresponding unit battery Connection fitting 31 in which 30 is fitted
Is welded to the peripheral side wall. Reference numeral 34 indicates the welding location. This type of unit battery is disclosed in, for example,
It is known from 58025, in which the unit battery is constituted by a cylindrical unit battery, and a donut-shaped insulating plate is interposed between the connection fitting and the lower unit battery. Also, in Japanese Patent Application Laid-Open No. 2000-100416, completed cells are stacked in a multi-stage form without using the above-described connection fittings, and welding electrode rods are brought into contact with both ends of the cell group to form an adjacent sealing plate. There has been proposed a method of forming a unit battery by welding an outer can at a stretch.

[0003]

As described above, in a unit battery in which adjacent batteries are fixed to each other via a connection fitting, a high-voltage unit battery can be constructed by using an existing battery as it is. However, connection fittings and insulating plates are indispensable to fix the batteries inseparably, and since the connection fittings are welded at multiple locations on the bottom wall and the peripheral wall, the manufacturing cost of the unit battery increases accordingly. . In addition, since adjacent batteries are electrically connected to each other via the connection fitting and the welded portion, the electrical resistance between the batteries increases by that much, and when many batteries are connected, the electrical resistance is increased. Increases to a level that cannot be ignored.

[0004] Further, a unit battery in which a welding current is applied to a completed unit cell group to join adjacent unit cells together,
This has the advantage of reducing the electrical resistance between the batteries, but because the welding current flows inside the completed battery, the joint between the positive electrode lead and the sealing plate joined by welding is melted by the large current during welding. And may be separated.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to form a unit battery without using a connection fitting and without impairing the reliability of the battery. It is an object of the present invention to provide a battery assembly, a unit battery, and a method of manufacturing the same, which can reduce the electric resistance of the battery and further improve the output voltage by reducing the electric resistance value between the batteries.

[0006]

The battery assembly of the present invention is used for connecting a plurality of unit batteries in series,
A metal battery case serving as one electrode terminal of the unit battery and a metal sealing plate serving as the other electrode terminal are integrally formed.

The battery case and the sealing plate are welded and fixed at a plurality of locations by a resistance welding method or a laser welding method.

A unit battery according to the present invention is constituted by using the above-mentioned battery assembly and a power generating element, and is constituted by connecting a plurality of unit batteries in series and inseparably.

In the method of manufacturing a unit battery according to the present invention, a step of housing a power generating element in the above-mentioned battery assembly, stacking the power generating elements in a multi-stage manner via packing, and temporarily assembling the battery assembly, Bending the opening of the battery case of the completed battery assembly, and integrating the sealing plates and the battery case, which face each other up and down via packing, so as to be inseparable from each other.

In the step of integrating each sealing plate and the battery case so as to be inseparable from each other, the upper and lower ends of the temporarily assembled battery assembly are held by a holder and driven to rotate.
The opening of each battery case is tightly wound to close the opening of the battery case.

In another sealing method, the upper and lower ends of the tentatively assembled battery assembly are held and rotated by a holder, and the opening of each battery case is formed in the case by a plurality of circumferentially divided molds. The battery case is bent and deformed to seal the opening of the battery case.

[0012]

The positive electrode terminal and the negative electrode terminal of the adjacent unit cells are welded in advance, and the unit cells are connected and fixed inseparably, and are electrically connected in series at the same time, so that there is no need to use a connection fitting. In addition, a unit battery can be constituted only by a plurality of unit batteries. Therefore, the manufacturing cost of the unit battery can be reduced as much as the connection fittings and the insulating plate can be omitted, and the overall length of the unit battery can be reduced. In addition, the electrical resistance between the welded unit batteries is reduced by the amount that the connection bracket can be omitted, so that the increase in the total resistance at the connection between the unit batteries is suppressed, and the output voltage of the unit battery is improved accordingly. it can. Since the battery case in the component state and the sealing plate are welded in advance to form a battery assembly, a power generation element is incorporated, and the adjacent battery assemblies are sealed to form a unit battery. There is no damage or deterioration of the power generating element due to the application of a large current during welding, and the reliability of the unit battery can be improved as compared with the case where the completed unit cells are directly welded.

When the bottom wall of the battery case and the positive electrode terminal of the sealing plate are welded at a plurality of locations by resistance welding or laser welding, the battery case and the sealing plate can be more firmly connected, and the electrical connection at the connection point between the two can be achieved. Resistance value can be reduced.

In a unit battery including a metal battery case, a power generation element accommodated in the battery case, and a metal sealing plate closing an opening of the battery case, a positive electrode terminal provided on an outer surface of the sealing plate is connected to an adjacent terminal. According to the connection structure in which the outer surface of the negative electrode terminal on the bottom wall of the battery case is welded, a high-voltage unit battery can be configured by simply using the existing components of the unit battery and changing the assembly procedure. Thus, unit batteries can be manufactured at lower cost.

In the method for manufacturing a battery according to the present invention,
Since the negative electrode terminal on the bottom wall of the battery case and the positive electrode terminal on the outer surface of the sealing plate are welded in advance to form a battery assembly, the battery case and the sealing plate to be welded to the battery case are securely connected. In addition, welding can be performed with high positional accuracy, the variation in electric resistance between the unit cells welded can be minimized, and the battery case and the sealing plate can be firmly connected. After this, a plurality of battery assemblies are stacked in a multi-tiered form, a sealing plate and a battery case are further assembled to temporarily assemble the battery assemblies, and then the openings are opened in the respective battery cases of the temporarily assembled battery assemblies. Bending is performed, and the vertically facing sealing plates and each battery case are inseparably integrated, so that unit batteries can be continuously produced while using the existing unit battery components as they are. Can be manufactured at lower cost.

In the step of integrating each sealing plate and each battery case, a sealing process of tightening the opening of each battery case with a winding roller while rotating and driving the upper and lower ends of the battery assembly with a holder. According to this, the opening of the battery case is uniformly wound around in the circumferential direction, and a unit battery having the same sealing property as the unit battery can be obtained.

While the upper and lower ends of the battery assembly are held by a holder and driven to rotate, the opening of each battery case is bent and deformed into the case inward by a plurality of circumferentially divided molds.
When closing the opening of the battery case, since the opening peripheral surface of each unit battery is simultaneously sandwiched and bent by a plurality of molds, the bending reaction force of the battery case can be canceled by each mold. Therefore, even when the number of unit cells constituting the battery assembly increases, the sealing process can be performed without any trouble, which is particularly advantageous for manufacturing a unit battery having a large number of unit cells.

[0018]

1 to 4 show an embodiment of a unit battery according to the present invention. In FIG. 1, the unit battery is configured in a state where a plurality of unit batteries 1 are electrically connected in series. Positive electrode terminal 8 of each adjacent unit battery 1 as described later
And the negative electrode terminal 9 are welded and integrated with each other. Each unit battery 1 is a button-type nickel-metal hydride battery, and a battery case 2 made of a metal plate.
And a power generation element housed in the battery case 2, a sealing plate 3 for closing an opening of the battery case 2, a packing 4, and the like. The power generating element includes a positive electrode body 5 made of a mixture of nickel hydroxide, a negative electrode body 6 made of a hydrogen storage alloy, a nonwoven fabric separator 7 interposed between the both, and injected into the battery case 2. And the alkaline electrolyte to be used. In the button type battery, the battery case 2 also serves as the negative electrode terminal 9, and the sealing plate 3 also serves as the positive electrode terminal 8.

The unit battery described above is manufactured through the steps shown in FIG. First, as shown in FIG. 2A, after the bottom wall 2a of the battery case 2 and the upper end wall 3a of the sealing plate 3 are respectively joined and positioned, the bottom wall 2a and the upper end wall 3a are pressed. Are sandwiched between a pair of upper and lower electrode rods 12 and 13 and spot-welded to form a battery assembly 14. At this time, as shown in FIG. 3, three welding locations are provided in the circumferential direction of the joining surface to secure a sufficient welding strength between the battery case 2 and the sealing plate 3 and further reduce the electric resistance value at the joining portion as much as possible. To do.

Next, as shown in FIG. 2 (b), the battery assemblies 14 in which the power generating elements such as the positive and negative electrodes are loaded in the battery case 2 are stacked in a multi-stage manner, and the battery assembly 15 is temporarily Assemble. At this time, the sealing plate 3 is independently assembled on the upper part of the uppermost battery assembly 14, and the battery case 2 loaded with the power generating element is mounted on the lower part of the lowermost battery assembly 14. Build alone.

Finally, as shown in FIG. 2C, the opening of each battery case 2 is sealed. For details, see Battery Assembly 1
5 is pressed between the pair of holders 16 and 17, and while rotating the battery assembly 15 and the holders 16 and 17, the rotationally driven winding roller 18 is pressed against the opening peripheral surface of each battery case 2. Then, as shown in FIG. 4, the packing 4 is bent and deformed to the inside of the case, and the packing 4 is clamped by the tightening portion 19. The winding roller 18 is provided with a forming groove 18a that bends and deforms the opening wall of the battery case 2 into a predetermined shape.
As described above, when the sealing process is performed for each unit battery 1 of the battery assembly 15 assembled in a multi-stage, as the number of the unit batteries 1 increases, it is more difficult for the holders 16 and 17 to hold the battery assembly 15 with the clamping pressure. Becomes In this case, as shown in FIG. 2C, the peripheral surface of the case is supported by one or several receiving rollers 20 facing the tightening roller 18, and the lateral pressing force of the tightening roller 18 is received by the receiving roller. 20. By performing the sealing process on all the unit batteries 1, as shown in FIG. 1, a unit battery in which the battery case 2 and the sealing plate 3 are directly welded can be obtained.

The sealing process of the battery case 2 may be performed by the method shown in FIGS. There, battery assembly 1
5 is pressed between the pair of holders 16 and 17, and while slowly rotating the battery assembly 15 and the holders 16 and 17, the opening wall of the battery case 2 is formed by the mold 22 divided into three parts in the circumferential direction. Is gradually bent toward the inside of the case to form a seal portion 23 similar to the above-mentioned tightening portion 19 in a circular shape. Each mold 22 is formed with a recess 22a similar to that of the winding roller 18. In this case, the peripheral surface of the battery case 2 is evenly pressed inward by the three dies 22, so that there is no need to use the receiving roller 20.

In addition to the above embodiment, the positive electrode terminal may be formed separately from the battery case. The present invention can also be applied to a sealed cylindrical battery. The welding between the battery case and the sealing plate may be performed by a resistance welding method other than spot welding, a laser welding method, or the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a unit battery.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the unit battery.

FIG. 3 is a plan view of the battery assembly.

FIG. 4 is a vertical cross-sectional view showing a state of closing a battery case.

FIG. 5 is a vertical cross-sectional view showing a separately sealed state of the battery case.

FIG. 6 is a plan view for explaining a sealing processing state in FIG. 5;

FIG. 7 is a longitudinal sectional view of a conventional unit battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unit battery 2 Battery case 2a Battery case bottom wall 3 Sealing plate 8 Positive electrode terminal 9 Negative electrode terminal 14 Battery assembly 15 Battery assembly 16/17 Holder 18 Rolling roller

Claims (6)

[Claims] 1. A battery assembly for connecting a plurality of unit batteries in series, comprising a metal battery case serving as one electrode terminal of the unit battery and a metal battery case serving as the other electrode terminal. A battery assembly in which a sealing plate is integrated. 2. The battery assembly according to claim 1, wherein the battery case and the sealing plate are welded and fixed at a plurality of positions by a resistance welding method or a laser welding method. 3. A unit battery comprising the battery assembly according to claim 1 and a power generating element, wherein a plurality of unit batteries are connected in series and inseparable. 4. A step of storing a power generating element in the battery assembly according to claim 1 or 2, stacking the power generating elements in a multi-stage manner via packing, and temporarily assembling the battery assembly, and a temporarily assembled battery assembly. 4. A method of manufacturing a unit battery according to claim 3, further comprising the step of: bending the opening of the battery case to integrate the respective sealing plates and the battery case facing each other up and down via packing so as to be inseparable from each other. 5. The battery assembly as claimed in claim 3, wherein the upper and lower ends of the temporarily assembled battery assembly are held and rotated by a holder, and the opening of each battery case is tightly wound to close the opening of the battery case.
Or the manufacturing method of the unit battery of 4. 6. An opening of each battery case is bent inward by a plurality of molds divided in the circumferential direction while the upper and lower ends of the temporarily assembled battery assembly are held by a holder and driven to rotate. The method for manufacturing a unit battery according to claim 3, wherein the opening of the battery case is sealed.