JPS63218149A - Manufacture of storage battery - Google Patents

Abstract

PURPOSE:To improve the sealability of terminal parts such as leading edge and cover by using a mold, which forms a cavity provided with surrounding walls around terminal members, to hold the wall part, upon which a secondary molded part is formed by injection of a same kind of thermoplastic resin. CONSTITUTION:A electrode plate group 13 is inserted into a battery jar 11 through the opening 12, and a tab terminal 14 as a terminal member is connected electrically, and a secondary molded part 17 comprises the same kind of thermoplastic resin. At a part where the tab terminal 14 is located in the battery jar 11, a pair of molds 19, 20, which forms a cavity 18 provided with surrounding walls around the circumambient space, is allocated holding a wall part 16 between them. Then, the resin is injected from an injection nozzle 22 to form the secondary molded part 17 upon internal surface of the wall part 16. A cover 25 is heat-fused on the battery jar 11, bonding with both of a fringe art 28 of the opening and a peripheral part of the tab terminal 14 at the secondary mold part 17. By the arrangement, the electrolyte leakage is avoided because of no crevice formation.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for manufacturing a storage battery, and in particular,
The present invention is characterized by a method of manufacturing a portion that leads to the outside a terminal member electrically connected to a group of electrode plates housed in a storage battery.

[Prior Art] Storage batteries are used as power sources for portable devices such as portable video cameras. Since storage batteries intended for such uses can take various positions, they must be of a sealed type that does not leak.

In a sealed storage battery, the part where the problem of liquid leakage is most likely to occur is the part where the terminal member is led out.

This is because, in order to function, the terminal member must be provided to penetrate the wall of the battery case, and a gap is likely to occur between the terminal member and the battery case at such a penetrating portion.

An example of the structure of a lead-out portion of a terminal member conventionally employed in a sealed storage battery is shown in FIG.

In Fig. 12, the storage battery case consists of a case body 1 and a lid 2.
It consists of The lid 2 is provided with a container portion 3, and a scraper 4 made of lead is placed through the bottom wall of the container portion 3.

The scraping bar 4 is electrically connected to a group of electrode plates (not shown) housed within the battery case body 1. An O-ring 5 is arranged in a compressed state so as to surround the scraper bar 4 within the small diameter portion of the bottom of the container portion 3 . Then, the tab terminal 6 is welded to the upper end surface of the scraper 4. The tab terminal 6 is, for example,
It is made of a lead-plated iron plate, and is bent into an L shape so that it protrudes from the top surface of the lid 2.

In order to realize a sealing structure for the lead-out portion of the terminal member constituted by the scraping bar 4 and the tab terminal 6 as described above, the container portion 3 is filled with a sealing material 7 such as epoxy resin.

In such a conventional technique, the material of the lid 2 is particularly required to have excellent adhesiveness with the sealing material 7.

Therefore, the lid 2 is usually made of acrylonitrile butadiene styrene (ABS) resin. When the lid 2 is made of ABS resin in this way, the battery case body 1
It is also made of ABS resin, and the connection between the battery case body 1 and the lid 2 is as follows.
This is achieved by adhesive 8.

On the other hand, it is also known to construct a battery case from an olefin resin such as polypropylene or a copolymer of polypropylene and polyethylene. However, if the battery case body 1 and the lid 2 shown in FIG. 12 are constructed using olefin resin, the adhesion with other resins or adhesives is poor, so the case shown in FIG. Even if a suitable sealing material 7 is used, not only the sealing performance cannot be expected, but also the adhesive 8 cannot be used for joining the battery case body 1 and the lid 2. Of these, the battery case body 1 and lid 2
Although the problem of joining with the terminal member can be solved by applying thermal welding instead of the adhesive 8, the sealing performance at the lead-out portion of the terminal member could not be solved immediately.

Therefore, when using a battery case made of olefin resin, there is a method described in Japanese Patent Laid-Open No. 47-44132 as a method for effectively sealing the lead-out portion of the terminal member. In this prior art, the lid is provided with a penetrating portion for the terminal member, and when the terminal member is passed through the lid, a container-shaped portion at the bottom is formed around the terminal member, and then a metal plate is attached to the top surface of the lid. A mold is placed and the same olefin resin is injected around the terminal member to create a sealing effect. This prior art advantageously solves the problems caused by using adhesives. Furthermore, based on this method, it has also been proposed to make the shape of the cavity filled with the secondarily injected olefin resin as described above more complex in order to further enhance the sealing effect ( For example, Japanese Patent Publication No. 55-26591 and Japanese Patent Publication No. 55-37063).

[Problems to be Solved by the Invention] However, in the above-mentioned two typical conventional techniques, the battery case body 1 and the lid 2 are formed from ABS resin, and the terminal member (scraper 4 and tab terminal 6
), and a method in which the battery case body and lid are made of olefin resin and the lead-out portion of the terminal member is sealed by secondary molding. There was a problem.

First, in the former conventional technology, the sealing material 7 and the battery case body 1
A drying oven is required to dry (cure) the adhesive 8 used for joining the lid 2 and the lid 2, which lengthens the work line and requires a large space for manufacturing equipment. 7 and the adhesive 8 take a relatively long time to harden, resulting in poor workability. In addition, the adhesive constituting the sealing material 7 etc. naturally hardens between the time it is prepared and the time it is applied to a predetermined location, and some of the prepared adhesive may be thrown away without being used. There were quite a few. In order to eliminate such adhesive waste, work must be carried out according to a detailed plan.
In actual manufacturing processes, it is virtually impossible to proceed as planned. This also causes the above-mentioned decrease in workability and increases costs. Furthermore, ABS resin has higher abrasive cost than olefin resin, and therefore, if possible, there has been a desire to construct the battery case body and lid using olefin resin, as in the latter prior art. This request also indicates that it is better to join the battery case body 1 made of olefin resin and the lid by heat welding than to bond the battery case body 1 made of ABS resin and the lid 2 with adhesive. It is also associated with the fact that the joint and seal between the tank body and the lid is more reliable.

Next, the latter conventional technique, that is, a method in which the battery case body and lid are made of olefin resin, and the lead-out portion of the terminal member is sealed with secondarily molded olefin resin, is as follows. There were problems as described in . That is, the same can be said about the former prior art shown in FIG.
The techniques described in Japanese Patent Publication No. 55-26591 and Japanese Patent Publication No. 55-37063 all involve introducing the terminal member through the lid, and then connecting the lid and the terminal member. The idea was to apply a sealing treatment between the two. This is related to the manufacturing process sequence of the storage battery. When manufacturing a storage battery, the steps are generally performed in the following order: inserting a group of electrode plates holding terminal members into a battery case body, and then joining a lid to the battery case body. Therefore, the sealing member is formed by secondary molding after the battery case body is closed with the lid. In this case, the mold for forming the cavity into which the sealing member is to be injected can only be placed on the - side of the lid, and the mold or other special supporting member can be placed on the lower side of the lid. I can't place anything. Therefore, a part of the wall defining the cavity for injection molding of the sealing member must be formed by the lid itself without any special support. As a result, the strength of the walls that define the cavity tend to be insufficient in some areas, and the injection pressure of the sealing member cannot be increased too much, resulting in a decrease in the reliability of the sealing effect. In some cases, the sealing material spewed out into the battery case from the gap between the terminal member and the lid.

Therefore, the present invention solves the problems when using an adhesive to bond the battery case body and the lid and seal the lead-out portion of the terminal member, and also seals the lead-out portion of the terminal member. The present invention aims to provide a method for manufacturing a storage battery that can take advantage of the advantages of secondary injection molding of components.

[Means for Solving the Problems] The present invention first provides a battery case body having an opening, a group of electrode plates housed in the battery case body, and a terminal electrically connected to the group of electrode plates. A method for manufacturing such a storage battery, comprising: a member; and a lid having a through hole through which the terminal member passes and leading to the outside, and which is joined to the battery case body so as to close an opening of the battery case body. It is characterized by the following steps: That is, (1) manufacturing the battery case body and the lid from the same type of thermoplastic resin, (2) inserting the electrode plate group holding the terminal member into the battery case body, thereby causing the terminal member to protrude from the opening of the battery case body and bringing a part of the terminal member into contact with the inner surface of the wall of the battery case body; A mold for forming, in a portion of the terminal member located within the battery case body, a cavity defined by a wall surface that surrounds a space around the terminal member while including the inner surface of the wall of the battery case body as a part. (4) injecting into the cavity a thermoplastic resin of the same type as the thermoplastic resin constituting the battery case body and the lid;
thereby forming a secondary molded part that swells from the inner surface of the wall of the battery case body and surrounds the terminal member, and (5) with the terminal member penetrated through the through hole, the lid is A step of thermally welding both the opening edge of the battery case body and the peripheral portion of the terminal member in the secondary molded part.

[Operations and Effects of the Invention] According to the present invention, as is clear from the above-mentioned steps,
Since there is no need to perform bonding with an adhesive, an inexpensive olefin resin can be used as the material for the battery case body and lid. In addition, there are problems in the manufacturing process when using adhesives, such as the need for a drying oven, which lengthens the work line, requires a large amount of equipment space, and the relatively long time it takes for the adhesive to harden. This solves the problems such as long operation and poor workability.

In this invention, before the battery case body is closed by the lid,
A secondary molded portion is formed that functions as a sealing member for sealing the lead-out portion of the terminal member. Therefore, a mold for forming a cavity into which this secondary molded part is to be injected can be arranged so as to sandwich the wall of the battery case body. Therefore, by increasing the pressure between the mold and the wall of the battery case main body, it is possible to prevent even the slightest gap from forming leading to the cavity, and it is possible to increase the injection pressure of the resin forming the secondary molded part. This not only makes it possible to firmly integrate the secondary molded part with the wall of the battery case body, but also allows the terminal member to be more tightly tightened by the secondary molded part, allowing the terminal member and the secondary molded part to There is no gap between the two that can cause liquid leakage.

After forming such a secondary molded part, a lid is heat welded to close the opening of the battery case body, but such heat welding does not cover the opening edge of the battery case body and the secondary molded part. The lid is simultaneously joined to both peripheral portions of the terminal member.

Therefore, such a thermal welding operation is efficient, and the conventional thermal welding equipment for the battery case body and the lid can be used as is or only partially.

Furthermore, according to the present invention, the secondary molded part, which is likely to cause poor appearance of the molded product, is hidden inside the battery case when the product is manufactured, so that the appearance of the storage battery as a product is not impaired. .

[Embodiment] A first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

First, in FIG. 1, a part of the battery case body 11 is shown broken. An opening 12 is formed in the battery case body 11, and the electrode plate group 13 is inserted through this opening 12 and housed in the battery case body 11.

A tab terminal 14 serving as a terminal member is electrically connected to the electrode plate group 13 . In this embodiment, a tab terminal 14 is attached to a connecting member 15 made of lead that electrically connects the electrode plate group 13 in parallel.
is welded. The tab terminal 14 is made of, for example, an iron plate plated with lead, and is brought into contact with the inner surface of the wall 16 of the battery case body 11, as shown in FIG.

As can be seen by comparing FIG. 3 with FIG. 1, in the state shown in FIG.
is formed so as to swell from the inner surface and surround the tab terminal 14.

A method for forming such a secondary molded portion 17 will be explained with reference to FIG. 2.

The battery case body 11 is made of an olefin resin such as polypropylene, polypropylene/polyethylene copolymer, or the like. In addition, in order to increase the strength, such a resin may contain, for example, about 15 to 20% of talc. The secondary molded portion 17 is also made of the same type of thermoplastic resin. As shown in FIG. 2, in the portion of the tab terminal 14 located inside the battery case body 11, a cavity 18 is defined by a wall surface that surrounds the space around the tab terminal 14 and includes the inner surface of the wall portion 16 as a part. A pair of molds 19 and 20 for forming the wall portion 16
are placed in between. Then, resin is injected from an injection nozzle 22 via a sprue 21 formed between the molds 19 and 20.

After completing such injection, the molds 19 and 20 are released in the directions of arrows 23 and 24, respectively, and the resin remaining in the sprue 21 is removed, resulting in a secondary molded part as shown in FIG. 17 is formed on the inner surface of wall 16. In addition, the second
Although the shape of the cavity 18 is not shown in detail in the figure, its shape can be understood from the outer shape of the secondary molded part 17 shown in FIG.

In FIG. 3, the lid 25 is shown separated from the battery case body 11 and partially broken. This lid 25 is also made of the same type of resin as the resin that makes up the battery case body 11. A through hole 26 is formed in the lid 25 to receive the tab terminal 14 protruding from the opening 12 of the battery case body 11. Also,
As shown by the dotted line, the lower surface of the lid 25 has a secondary molded part 17.
A rib 2 that protrudes downward and has a shape corresponding to the upper surface of the
7 is formed.

FIG. 4 shows a sectional view of a state in which the lid 25 is thermally welded to the battery case body 11. For such thermal welding, in addition to a method using a conventionally well-known hot plate, a method of applying ultrasonic waves to the battery case body 11 and the lid 25 in a state in which they are overlapped may be used.

In FIG. 4, the tab terminal 14 passes through the through hole 26 and is led out to the outside, and the lid 25 is connected to the battery case body 11.
The tab terminal 14 is thermally welded to both the opening edge 28 and the surrounding portion of the tab terminal 14 in the secondary molded portion 17 . In this embodiment, the upper end surface of the opening end edge 28 of the battery case body 11 and the upper end surface of the secondary molded part 17 are located on the same plane, and the opening end provided on the lid 25 side A rib 29 facing the edge 28 and a rib 27 facing the secondary molded part 17 are located on the same plane. Therefore, the heat welded part between the battery case body 11 and the lid 25 including the secondary molded part 17 extends on the same plane, and in the heat welding process using a hot plate, it is possible to A shaped hot plate can be used. However, if such an advantage is not desired, a step may be provided between the upper end surface of the open end edge portion 28 and the upper end surface of the secondary molded portion 17.
A corresponding portion of the lid 25 may also be provided with a considerable step.

A second embodiment of the invention is shown in FIGS. 5-7. Since this embodiment has many points in common with the first embodiment described above, corresponding parts are designated by the same reference numerals with the suffix "a" in the drawings. The following explanation will be omitted.The points of the second embodiment that are different from the first embodiment will be explained below.

First, as shown in FIG. 5, the connecting member 15a integrally forms a fence rod 30. The fence rod 30 has a semicircular cross section and is in contact with the inner surface of the wall portion 16a. Also, fence rod 30
A plurality of grooves 31 are provided on the outer circumference of the upper end of the cylindrical surface 2, thereby giving the surface of the fence rod 30 an uneven shape. The tab terminal 14a is welded to the upper end surface of such a scraper 30.

Note that, as can be seen from FIG. 6, the tab terminal 14a does not contact the inner surface of the wall portion 16a. In this example,
The terminal member is composed of a tab terminal 14a and a scraper 30.

In order to form the secondary molded part 17a by injection molding as shown in FIG. 7, a pair of molds 19a and 20a as shown in FIG. 6 are used. The cavity 18a formed by these molds 19a and 20a is sized to accommodate the portion of the scraper 30 in which the groove 31 is formed and the portion of the tab terminal 14a located inside the battery case body 11a. Therefore, as shown in FIG. 7, when the secondary molded portion 17a is formed, the portion of the fence rod 30 in which the groove 31 is formed is embedded therein. Due to the presence of these grooves 31,
This has the advantage that the creepage distance at the interface between the scraper 30 and the secondary molded part 17a becomes longer, and the sealing effect is further enhanced.

The illustration of the lid heat welded to the battery case body 11a shown in FIG. 7 and the state after heat welding are omitted, but for example, the through hole 26 in the lid 25 shown in FIGS. 3 and 4 is omitted.
With only a slight change in the position of the lid, the same heat welding can be performed using a substantially similar lid as in the first embodiment.

8 to 10 show a third embodiment of the invention. This embodiment also includes many elements in common with the two embodiments described above, especially the second embodiment, so the reference numbers used in the first or second embodiment are suffixed with ".
By adding "b", the explanation of ff1ffl will be omitted.

Referring to FIG. 8, as is clear from comparison with FIG. 7, a recess 32 is formed in the upper end surface of the secondary molded portion 17b, and a rib 33 is formed so as to surround it. The upper end surface of the rib 33 is located on the same plane as the upper end surface of the open end edge 28b of the battery case body 11b.

The other configurations are similar to the second embodiment.

In order to obtain the secondary molded part 17b shown in FIG. 8, three molds 34, 35, and 36 as shown in FIG. 9 are used.

When these molds 34, 35, 36 are released, the arrows 37. 38. It is moved in 39 directions. The reason why the three molds 34°35.36 are used in this way is to form the recess 32 on the upper end surface of the secondary molded part 17b. contributes to

FIG. 10 shows a state in which the lid 25b is thermally welded to the battery case body 11b. As is clear from Figure 10,
! The rib 27b formed on the 25b is the secondary molded part ITb.
It faces the rib 33 formed in the. Therefore, according to this embodiment, although the molding operation of the secondary molded part 17b is a little complicated, all the parts to be heat welded on each side of the battery case body 11b and M25b have a rib-like protruding shape. Therefore, thermal welding can be performed more quickly and with higher reliability.

Note that also in the first embodiment described above, the lid 25 includes:
Since the ribs 27 were formed, rapid and reliable thermal welding can be expected, although this is not the case in the third embodiment. However, the ribs 27.27b on the lids 25, 25b
Alternatively, the presence of the ribs 33 in the secondary molded part 17b is not essential, and at least when the lid is heat welded to the opening edge of the battery case body, this lid is attached to the peripheral part of the terminal member in the secondary molded part. It suffices if the contact portion has a contact portion that can be thermally welded.

FIG. 11 shows a fourth embodiment of the invention. This embodiment also includes many elements in common with the second embodiment described above. Therefore, by adding the suffix "C" to the reference numerals used in the second embodiment, or by changing the suffix "a#" of the reference numerals used in the second embodiment to "C", duplicate explanations will be omitted. do.

Referring to FIG. 11, near the upper end of the battery case body 11c,
A step 40 extending outward is formed.

Then, on this step 40, a rib 41 is provided on the battery case body 1.
It is formed integrally with 1c.

The flat surface of the scraping bar 30c is arranged so as to contact both the inner surface of the wall portion 16c and the rib 41 of the battery case body 11c. A tab terminal 14C is welded to the scraper bar 30c.

In this fourth embodiment as well, a method similar to that shown in FIG. 6 is used to form the secondary molded portion 17c. According to this embodiment, in the secondary molded part 17c, the resin constituting the secondary molded part 17c also spreads between the scratching bar 30C and the inner surface of the wall part 16c of the battery case body 11c. The sealing performance around the scraping bar 30c is further improved compared to the embodiment shown in FIG.

Although the invention has been described above in connection with the four exemplary embodiments shown, several variant embodiments are possible within the scope of the invention.

For example, olefin resin is used as a resin material for the battery case body, lid, and secondary molded parts because its melting temperature is relatively clear, making it easy to perform heat welding and secondary molding. Other thermoplastics may be used, although they are advantageous.

Furthermore, although the illustrated embodiment described above is particularly effective when applied to a sealed storage battery, it does not preclude application to conventionally widely used storage batteries equipped with a gas discharge port and a liquid replenishment port. Of course.

In addition, the second and third parts explained with reference to Figs. 5 to 7, Figs. 8 to 10, and Fig. 11, respectively.
In the fourth embodiment, instead of using the tab terminals 14a, 14b, 14c as terminal members, members corresponding to the scrapers 30, 30b, 30c are made to have a length that extends further upward, and are attached to the upper surface of the lid. It may be exposed. In addition, in each of the illustrated embodiments, the tab terminal 1
4, 14a, 14b, and 14c are used because when connecting to the power input terminal of a device in which such a storage battery is used, tab terminals made of iron plates or the like are used, compared to scrapers made of lead itself. This is because it is more reliable in terms of strength. Further, the tab terminal may be bent in an appropriate direction on the outer surface of the lid depending on the usage situation.

In addition, in order to reliably prevent the occurrence of gaps between the terminal member and the secondary molded part, the terminal member, that is, the tab terminal and/or
Alternatively, the surface of the scraper may be subjected to surface treatment such as resin coating.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining a first embodiment of the present invention, and FIG. 1 shows a partially cut away battery case body 11 that houses an electrode plate group 13. FIG. 2 is a cross-sectional view showing the arrangement of molds 19 and 20 for forming the secondary molded part 17, and FIG. FIG. 4 is a partially cutaway exploded perspective view showing the battery case body 11 together with the lid 25, and FIG. 4 is a sectional view showing the state after the lid 25 is heat-welded to the battery case body 11. 5 to 7 are diagrams for explaining a second embodiment of the present invention, in which FIG. 5 is a diagram corresponding to FIG. 1, and FIG. 6 is a diagram corresponding to FIG. 2. FIG. 7 is a diagram corresponding to FIG. 3, although illustration of the lid is omitted. 8 to 10 are diagrams for explaining a third embodiment of the present invention, in which FIG. 8 is a diagram corresponding to FIG. 7, and FIG. 9 is a diagram corresponding to FIG. 2. Alternatively, it is a diagram corresponding to FIG. 6, and FIG. 10 is a diagram corresponding to FIG. 4. FIG. 11 is a diagram for explaining the fourth embodiment of the present invention, and is a sectional view showing a part of the battery case body 11c after forming the secondary molded part 17c. FIG. 12 is a cross-sectional view showing a storage battery according to the prior art of the present invention, particularly a portion from which a terminal member is led out. In the figure, 11. lla, llb, lie are the battery case bodies, 12, 12a, 12b, 12c are openings, 13.13a
, 13b is a group of electrode plates, 14, 14a. 14b and 14c are tab terminals (terminal members), 16° 16a
, 16b, 16c are wall portions, and 17, 17a. 17b is a secondary molding part, 1g, 18a, 18b are cavities, 19.19a, 20.20a, 34° 35.36 are molds, 22 is an injection nozzle, 25, 25b is a lid, 26, 2
6b is a through hole, 27, 27b. 29.29b, 33 are ribs, 28, 28a, 28b are opening edge parts, 30. 30 b and 30 c are pole bars (terminal portion shrines).

Claims (5)

[Claims] (1) A battery case body having an opening, a group of electrode plates housed in the battery case body, a terminal member electrically connected to the plate group, and a terminal member that is passed through and led out to the outside. In the method for manufacturing a storage battery, the storage battery has a through-hole and a lid joined to the battery case body so as to close an opening of the battery case body, wherein the battery case body and the lid are each made of the same type of thermoplastic material. manufacturing from resin; inserting the electrode plate group holding the terminal member into the battery case body, thereby causing the terminal member to protrude from the opening of the battery case body; bringing a part of the terminal member into contact with the inner wall of the battery case body; A mold for forming a cavity defined by a wall surface surrounding the space around the terminal member as a part,
placing the wall portions of the battery case body in between, and injecting into the cavity a thermoplastic resin of the same type as the thermoplastic resin constituting the battery case body and the lid; forming a secondary molded portion that swells from the inner surface of the wall portion and surrounds the terminal member; and with the terminal member penetrated through the through hole, the lid is attached to the opening edge of the battery case body and the A method for manufacturing a storage battery, comprising: thermally welding both peripheral portions of the terminal member in the secondary molding part. (2) the thermoplastic resin is an olefin resin;
A method for manufacturing a storage battery according to claim 1. (3) The method for manufacturing a storage battery according to claim 1 or 2, wherein the heat-welded portion of the battery case body and the lid, including the secondary forming portion, extends on the same plane. (4) The method for manufacturing a storage battery according to any one of claims 1 to 3, wherein the thermally welded portion in the secondary molded portion is provided with a rib-like protruding shape. (5) The storage battery according to any one of claims 1 to 4, wherein the heat-welded portion of the lid to the secondary molded portion has a rib-like protruding shape. Production method.