JP2003297299A - Battery jar for lead acid storage battery and production process thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery jar which can practice fabricating related to TTP connection of an upper portion of a partition wall without any trouble. <P>SOLUTION: Gate position of a mold is provided asymmetrically with respect to the center line of a bottom surface of a battery jar. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-acid battery case and a method for manufacturing the same, and more particularly to a lead-acid battery case using a highly rigid resin material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Most lead-acid battery cases are acid-resistant,
Molded products of polypropylene resin are used because of their oxidation resistance, oil resistance, heat resistance, workability, mechanical strength, material cost, and the like. However, in the valve-regulated lead-acid battery, polypropylene is relatively flexible, and it is necessary to suppress the swelling of the battery case due to the generation of gas during charging or the expansion of the battery case because polypropylene is relatively flexible. It is used as a material for battery case.

As one of such materials, thermoplastic synthetic resin to which various fillers are added to improve rigidity, for example, polypropylene, short fibers such as glass and talc, and fine powder are contained in an amount of 5 to 30% by weight. % Added.

In order to mold a battery case with such a high-rigidity resin material, similar to ordinary injection molding, molten resin is heated to a high temperature on one or more gates of a mold body having a battery container-shaped cavity.・ Injected at high pressure. The injection of the resin and the fusion itself in the cavity are completed in a few seconds, after which the resin is removed after solidification.

[0005]

Generally, in injection molding, the direction of resin flow depends on the position of the gate. If the molded product is rod-shaped, it is simple,
In the case of a form such as a monoblock battery case, the resin flowing from one gate encounters and fuses with the resin from another gate to be molded into a predetermined shape. The line fused in this way is called a weld line, and if the materials and molding conditions are selected, there will be no problem in terms of appearance and strength.

However, in the case of a high-rigidity resin material, although the fine powder glass or talc added is uniformly dispersed in the pellet, a part of the additive material is striped due to the flow at the time of injection molding. The pattern clearly appears on the weld line, which not only lowers the product value but also affects the mechanical strength. In the case of battery case for storage battery, this defect is likely to appear in the partition walls between cells, and if this part is processed, cracks occur, or damage that is not visible even if it does not occur occurs, resulting in leakage of electrolyte or leakage of electricity. In particular, in the case of a control valve type lead-acid battery, airtightness between cells is not ensured, so there is a drawback that the battery performance is greatly affected, such as the capacity reduction of a specific cell and the expected life cannot be exhibited.

On the other hand, since the demand for higher output of batteries has been increasing in recent years, it is necessary to use a high-rigidity material to reduce the thickness of the battery case. In addition, in the electrode plate group configuration of a monoblock battery in which a plurality of cells are arranged in a line with the orientation of the electrode plates parallel to the long side of the battery case, in order to reduce the weight and reduce the voltage drop loss, the cell-cell connecting body is divided into partitions. It is desirable to design for penetrating through the center of the upper part (TTP connection). For this reason, in the case of the conventional battery case molded by the gate position, the weld line appears near the center of the partition wall, and when the hole is drilled in this portion, or the adjacent cells are connected and connected by the resistance welding machine. At this time, problems such as cracks in the partition walls along the weld line occur.

[0008]

In order to solve these drawbacks, the invention according to claim 1 is used for a monoblock lead-acid battery in which the connecting position between the cells of the electrode plate group strap is arranged near the center of the cell spacing wall. An injection-molded battery case using a high-rigidity resin material, which is a battery cell for a lead storage battery having a resin weld line in a portion other than the central upper portion of the cell spacing wall.

According to a second aspect of the present invention, in the manufacturing method for producing the lead-acid battery case according to the first aspect, the position of the gate of the injection molding die is set so that the lower side of the cell interval wall of the case is It is characterized in that it is set on the bottom of the battery case between the center of the partition and the side wall of the battery on the line intersecting the bottom of the battery case.

According to a third aspect of the present invention, in the manufacturing method for producing the battery case for a lead storage battery according to the first aspect, the position of the gate of the injection molding die is set so that the lower side of the cell spacing wall of the battery case is It is characterized in that it is set on the bottom of the battery case near the side wall on the line intersecting the bottom of the battery case.

According to a fourth aspect of the present invention, in the manufacturing method for producing the battery case for a lead storage battery according to the first aspect, the position of the gate of the injection molding die is set so that the lower side of the cell interval wall of the battery case is It is characterized in that it is set asymmetrically on the bottom of the battery case centering on the line intersecting the bottom of the battery case.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a bottom surface of a battery case showing an example of a conventional gate position. 1 is the gate position, 3 is the bottom of the battery case, 4 is the side of the battery case, and 5 is the cell spacing wall. In a battery case in which the left and right are designed to be substantially symmetrical, the gate is usually provided at the center on the line where the lower sides of the short side wall and the cell spacing wall intersect the bottom surface of the battery case.

FIG. 2 is a plan view of the bottom of the battery case showing another example of the gate position. The gate is provided at the center of the bottom surface of each cell of the battery case.

3A to 3D show the progress of the resin flow in the partition wall of the battery case injection molded at the gate position of FIG. 1 with time, and 9 indicates the injection position. The high-rigidity resin used was a commercially available polypropylene resin containing 15% by weight of talc.

In FIG. 3a, the resin injected from the lower portion corresponding to the bottom of the battery case spreads over the entire bottom surface and at the same time flows to the long side surface which is slightly thicker, and to the partition wall portion which is slightly thinner than that. Also flows in. On the long side surface, the left and right sides are formed to have the same degree. Conventionally, the basic condition for injection molding has been to arrange the gate on the center line of the molded product because it is intended to mold the left and right parts uniformly. Next, the injected resin proceeds from the lower part to the central part and then to the upper part as shown in FIG. 3b. Finally, as shown in FIG. 3c, it reaches the upper edge of the partition wall, spreads inward, reaches the center top portion of the partition wall, and ends. FIG. 3d shows the weld line 8 formed at this time. This weld line is formed at the final arrival site of the injection resin, and remains at almost the same location of each partition.

FIG. 4 is a plan view showing an example of a bottom gate position when injection-molding an almost left-right symmetrical chamber according to the present invention, and 2 is a gate position. FIG. 5 shows the remaining of the injection molding resin weld line 8'in the molding according to FIG. 4, and 9'indicates the injection position. Although the progress of the injection molding resin in the mold is omitted, the injection position moves from the center to the side of the long side of the battery case on one side, so that the resin flow advances first on the moved side and on the bottom. Then, it moves from one long side surface to the other long side surface through the center and top of the partition wall and converges. Therefore, the weld line moved to the boundary portion between the long side surface where the injection gate is not provided and the partition wall, and did not appear at all on the central surface of the partition wall subjected to the secondary processing, and a molded product which did not cause any trouble was obtained. Note that the progress of these injection resins can be confirmed from simulations such as flow analysis in recent years, or from the process of sequentially injecting a fraction of the total resin amount when determining the total resin amount during injection molding. it can.

FIG. 6 shows a case in which a battery case whose left and right are substantially plane-symmetrical is provided at the center of the bottom surface and the long side surface of the battery case in the case where the mold is provided with the conventional gate 1 and the gate 2 of the present invention. FIG. 7 is a plan view showing the gate, and FIG. 7 shows the remaining weld lines obtained by opening these gates 1 and 2 at the same time.
According to this, it can be seen that the weld line 8'moves to the long side surface far from the position of the injection gate, as compared with the conventional one.

When the shape of the battery case is not almost symmetrical, the position of the injection gate is adjusted according to the specific conditions to form a battery case in which the weld line is not located at the center of the partition wall. it can.

[0020]

[Examples] In the production of a battery using a 12-volt monoblock battery case in which 6 cells are arranged in a row and which has a substantially uniform left and right, using a high-rigidity resin for a battery case in which polypropylene is mixed with 15% by weight of fine powder talc A hole for TTP connection was opened in the center of the partition wall of the battery case, and the number of occurrences of defects after resistance welding of the inter-cell connection body was investigated, and the results are shown in Table 1. The data is for 600 cells produced in line. There are 5 connection points for each target battery, so a total of 3
The data is for 000 locations. The number of occurrences of defects in the battery case by the conventional manufacturing method is shown in the upper row of Table 1 and that of the present invention in the lower row. It is apparent that the present invention avoids the occurrence of defects.

[0021]

【table 1】

[0022]

According to the invention of claim 1, the T on the upper part of the partition wall is
It is possible to supply a battery case that can perform secondary processing related to TP connection without any trouble.

According to the inventions of claims 2 to 4, it is possible to provide a method of manufacturing a battery case in which the secondary processing relating to the TTP connection on the upper part of the partition wall can be carried out without any trouble.

Therefore, the present invention has the effect of supplying a lead-acid battery, especially an exhaust valve type lead-acid battery, which guarantees superior quality, to consumers.

The present invention is particularly used for a monoblock battery having an electrode plate group in which a plurality of cells are arranged in a line with the orientation of the electrode plates parallel to the long side surface of the battery case, and the connecting body between the cells is located at the center of the upper part of the partition wall. With the structure of penetrating and connecting (TTP connection), the weight of the battery can be reduced and the loss due to the voltage drop can be reduced, which helps improve the energy and output per battery weight.

The present invention is directed to a monoblock battery in which a plurality of cells are arranged in a line with the orientation of the electrode plates being parallel to the long side surface of the battery case, and a plurality of connected electrode plate groups are arranged in parallel. It is effective even if used.

[Brief description of drawings]

FIG. 1 is a diagram showing a gate position of a battery case in a plan view of a bottom surface of a conventional battery case.

FIG. 2 is a diagram of another example showing the gate position of the battery case on the plan view of the conventional battery case bottom surface.

FIG. 3 is a diagram showing the progress of the resin flow in the partition wall over time in the battery case injection-molded at the gate position in FIG.

FIG. 4 is a diagram showing a gate position in a plan view of the bottom surface of the battery case according to the embodiment of the present invention.

FIG. 5 is a diagram showing an example of a weld line of a battery partition according to the method of FIG.

FIG. 6 is a diagram showing a gate position in a plan view of the bottom of the battery case of another embodiment of the present invention.

FIG. 7 is a view showing an example of a weld line of a partition wall of the battery case by the method of FIG.

[Explanation of symbols]

1 Conventional gate position 2 Gate position of the present invention 3 bottom of battery case 5 cell bulkhead 7 injection resin 8 Conventional weld line 8'weld line of the present invention 9 Conventional injection position 9'Injection position of the present invention

Claims (4)

[Claims] 1. An injection-molded battery case using a high-rigidity resin material, which is used in a monoblock lead-acid battery, in which an inter-cell connecting position of the electrode plate group strap is arranged near the center of a cell spacing wall. A battery case for a lead-acid battery that has a resin weld line on the part other than the upper center part of the partition wall. 2. A method of manufacturing a lead storage battery battery case according to claim 1, wherein the gate of the injection molding die is located at the bottom of the cell spacing wall of the battery container. A method of manufacturing a battery case for a lead storage battery, which is characterized in that it is set on a bottom surface of a battery case between a partition wall center and a battery case side wall on a line intersecting with the bottom surface. 3. The method for manufacturing a lead-acid battery container according to claim 1, wherein the gate of the injection-molding die is located at the bottom of the cell spacing wall of the container. A method of manufacturing a battery case for a lead storage battery, comprising setting the battery case bottom surface near a side wall on a line intersecting the bottom surface. 4. The method for manufacturing a lead-acid battery case according to claim 1, wherein the gate of the injection-molding die is located at the bottom of the cell interval wall of the case. A method for manufacturing a battery case for a lead storage battery, which is asymmetrically set to the center on a line intersecting the bottom surface.