JPH0782845B2 - Composite electrode material for lead acid battery and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composite electrode material for a lead storage battery and a method for manufacturing the same, and in particular, a lightweight lead storage battery formed by laminating a lead plate and a resin layer and having no peeling of an adhesive interface. TECHNICAL FIELD The present invention relates to a composite electrode material for use and a method capable of advantageously producing the same.

(Background Art) Lead acid batteries have been conventionally known as secondary batteries, and have been widely used in fields such as power sources for automobiles, households, and industrial fields. In addition, an electrode plate mainly made of lead is used in the form of a lead grid or an expanded electrode plate as an electrode in such a lead-acid battery, but with the progress of the electronics field, the device is rapidly becoming cordless. Against this background, there is a demand for weight reduction of such heavy lead-acid batteries, and above all, there is a great demand for weight reduction of heavy electrode plates mainly composed of lead.

By the way, weight reduction of electrodes in such lead-acid battery,
Further, in order to meet the demand for higher functionality, it is conceivable that the electrode has a hybrid structure in which a lead plate and a lightweight resin material are integrally laminated and adhered. Adhesion at the interface between the lead plate to be composited and the resin material is very important because it is immersed in a sulfuric acid solution as a solution and causes the following chemical changes due to discharge and charge.

During discharge: Anode (negative electrode) Pb + SO ₄ ^2- PbSO ₄ + 2e ^- Cathode (positive electrode) PbO ₂ ＋ 4H ⁺ ＋ SO ₄ ^2- ＋ 2e ^- PbSO ₄ ＋ 2H ₂ O During charging: Cathode (anode) PbSO ₄ ＋ 2e ^- Pb + SO ₄ ^2- Anode (Cathode) PbSO ₄ ＋ 2H ₂ OPbO ₂ ＋ 4H ⁺ ＋ SO ₄ ² ＋ 2e ^- In short, metallic lead Pb is sulfated at the adhesive interface if it is not firmly adhered to the resin material due to the above chemical changes. Contact with liquid (electrolyte) and gradually lead sulfate
While changing to PbSO ₄ , lead sulfate PbSO ₄ is present at the anode (cathode) in the presence of water during charging and PbO ₂ , 4H ⁺ and SO ₄ ^2-
And 2e ^−, and there is an inherent problem of causing interface delamination between the lead plate and the resin material due to hydrogen 4H ⁺ etc. generated during such charging.

Further, conventionally, there is a bonding method by heat welding for bonding the surface of the metal salt as seen in solder, etc., but bonding with a dissimilar material such as resin is very difficult. is there. That is, since the surface of metallic lead has low activity, even if the lead plate and the intervening layer made of a resin material are bonded using a commonly used adhesive, the adhesive strength under normal conditions is not sufficient. Nonetheless, under the effect of chemical changes due to discharge / charging, strong adhesion could not be expected at all.

(Problem to be Solved) Here, the present invention has been made in view of such circumstances, and the problem to be solved is that a lead plate and a resin material are laminated for a lightweight lead acid battery. It is to provide a composite electrode material, and to improve the adhesiveness at the interface between the lead plate and the resin layer in such a composite electrode material, and further to firmly bond the lead plate and the resin layer. An object of the present invention is to provide a method capable of easily manufacturing the composite electrode material as described above.

(Solution) To solve the problem, the present invention has a laminated structure in which an olefin resin layer is interposed between lead plates having a predetermined thickness, and the olefin resin layer and the lead are provided. The plate is a halogen-containing polyolefin selected from the group consisting of chlorinated polyethylene, chlorosulfonated polyethylene, and halogenated butyl rubber, and 2,4,6-trimercaptotriazine or 2-mercaptobenzothiazole-dicyclohexylamine salt or the like. A composite electrode material for a lead storage battery is characterized in that the composite electrode material is bonded by using an adhesive composed of at least a cross-linking agent composed of both of the above and a lead oxide-based cross-linking auxiliary agent.

Further, the present invention, in order to produce such a composite electrode material for a lead storage battery, a halogen-containing polyolefin selected from the group consisting of chlorinated polyethylene, chlorosulfonated polyethylene, and halogenated butyl rubber, 2,4, On the surface of a lead plate having a predetermined thickness, an adhesive containing 6-trimercaptotriazine or 2-mercaptobenzothiazole / dicyclohexylamine salt or a crosslinking agent composed of both of them and a lead oxide-based crosslinking aid is blended. After coating, the lead plates are laminated so that the adhesive coated surfaces face each other, and an olefin resin layer is formed between the lead plates to form a laminated material, and then the laminated material is heated and pressure-bonded. It is a feature.

(Specific Structure) That is, in the lead-acid battery composite electrode material according to the present invention as described above, for example, as shown in FIG. 1, lead plates 2 and 2 having a predetermined thickness are arranged on the upper and lower sides, respectively. Since the olefin-based resin layer 4 is provided between the lead plate 2 and the olefin-based resin layer 4, the lead plate 2 and the olefin-based resin layer 4 are firmly bonded by the adhesive layer 6 made of the adhesive according to the present invention. is there. The thicknesses of the lead plate 2 and the olefin resin layer 4 are appropriately selected in consideration of the thickness of the entire composite electrode material in order to achieve the purpose of effective weight reduction. .

By the way, a resin layer (4) interposed in order to reduce the weight, which constitutes such a composite electrode material for a lead storage battery according to the present invention.
Must be formed of an olefin polymer, which is a water-resistant and water-repellent material. However, based on the battery reaction of the electrodes as described above, if the electrolytic solution is present between the lead plate (2) and the resin layer (4), hydrogen or the like is generated, which causes the hydrogen to be peeled from the interface during charging and discharging. This is because a problem is caused. Therefore, in order to prevent the electrolyte solution from penetrating or invading such an interface, the resin layer (4) needs to be formed of a water-resistant and hydrophobic polymer. It is also necessary that the material has resistance to the sulfuric acid solution which is the electrolytic solution.

When the target composite electrode material is formed as an expanded electrode plate, the olefin resin layer 4 generally has a bending elastic modulus of about 2000 to 7000 kg / cm ² and an elongation of 200% or more. Will be advantageously selected. Examples of the olefin resin that gives the resin layer 4 include known polyolefins such as polyethylene, polypropylene, and chlorosulfonated polyethylene, and modified products thereof. In the present invention, maleic anhydride is particularly preferable. A modified resin such as a polyolefin in which a polar group such as a carboxylic acid anhydride group or a carboxyl group is introduced by addition or the like is advantageously used.

Further, the adhesive layer 6 for firmly bonding the olefin resin layer 4 and the lead plate 2 to each other in the present invention is
Chlorinated polyethylene, chlorosulfonated polyethylene,
And a halogen-containing polyolefin selected from the group consisting of halogenated butyl rubber and a crosslinking agent of 2,4,6-trimercaptotriazine or 2-mercaptobenzothiazole dicyclohexylamine salt or both of them and a lead oxide crosslinking promoter. The adhesive is formed by using an adhesive formed by mixing at least an agent with the adhesive, and such an adhesive chemically reacts with the adhesive interface between the lead plate 2 and the olefin resin layer 4 by the action of heat or the like. It causes a strong bond and develops a stronger joint state.

The strong bonding mechanism between the lead plate and the olefin resin layer using the adhesive according to the present invention has not been sufficiently clarified, but the adhesive composition according to the present invention is used. When an object is heat-welded to the surface of metallic lead, a similar adhesive effect is recognized. Therefore, in the adhesive used in the present invention, by the action of heat or the like,
Halogen in a halogen-containing polyolefin, for example, chlorine: Cl is liberated to form a lead compound at the metal-lead interface, or a cross-linking agent also forms a lead compound at the metal-lead interface, or a free halogen, For example, by the reaction of free chlorine: Cl with the terminal SH group of the crosslinker compound,
The binding of the lead sulfide compound is induced at the metallic lead interface,
It is considered that a chemical bond is generated at the adhesive interface, and thus a strong adhesive force is realized.

And, in such an adhesive according to the present invention, when the intended composite electrode material is used as an expanded electrode plate, the bending elastic modulus of the halogen-containing polyolefin is 2000 to 7000 kg / cm3. ^{About 2} , growth 20
Those of 0% or more will be advantageously used.

Further, 2,4,6-trimercaptotriazine or 2-mercaptobenzothiazole dicyclohexylamine salt as a crosslinking agent, or both of them, will be used in a ratio effective for crosslinking the halogen-containing polyolefin, Generally, such a cross-linking agent is compounded in a proportion of about 1 to 20 parts by weight with respect to 100 parts by weight of the above-mentioned halogen-containing polyolefin.

Further, in the present invention, the lead oxide-based crosslinking aid is used as an acid acceptor and is produced during the crosslinking reaction.
It plays a role of absorbing acids such as HCl, and will be appropriately determined depending on the type and amount of the cross-linking agent, and the type of halogen-containing polyolefin, etc. It is added in a proportion of about 3 to 50 parts by weight with respect to parts.

The adhesive composition used in the present invention may optionally contain additives such as a promoter, a plasticizer, and a filler, in addition to the above-mentioned crosslinking agent and crosslinking auxiliary agent. Will be blended into.

By the way, when manufacturing the lead-acid battery composite electrode material having the structure according to the present invention as described above, first, with respect to the surface of the lead plate 2 on the side where the olefin resin layer 4 is bonded,
A solution of the above-mentioned adhesive, for example, an adhesive solution obtained by using an aromatic organic solvent such as toluene is applied, and the two adhesive-coated lead plates are opposed to each other in their adhesive-coated surfaces. As described above, the olefin resin layer 4 is formed between the lead plates 2 and 2 by a normal method to form a laminated material, and then the laminated material is heat-pressed to form an adhesive layer. The upper and lower lead plates 2, 2 are firmly bonded to both surfaces of the olefin resin layer 4 by means of 6.

The thermocompression bonding operation of the laminated material is to crosslink the adhesive layer 6 to induce the chemical bond as described above, and is generally 100 ° C to 170 ° C x 10 minutes to 24 hours. It will be carried out while sandwiching the laminated material under a certain condition. By improving the adhesive strength by such a post-vulcanization method, it is possible to minimize variations in quality in the manufacturing process.

Then, the plate-shaped composite electrode material having the cross-sectional structure as shown in FIG. 1 thus obtained, as well known, is subjected to a known process as an electrode plate for a lead storage battery, Although it is used in the form of an expanded electrode plate, etc., the composite electrode material according to the present invention has a structure in which a resin layer is interposed between the upper and lower lead plates, so that the weight reduction thereof can be achieved. This is achieved advantageously, and the lead plate and the olefin-based resin layer are joined together by a chemical bonding type bonding state, whereby the lead plate and the olefin-based resin layer are firmly bonded to each other. It is possible to satisfactorily avoid the occurrence of problems such as peeling of the adhesive interface due to the electrode reaction (chemical change in the electrode) due to, and also the surface treatment of the lead plate surface and the primer treatment are necessary to realize a strong adhesive force. At all, Simplification of the process Te is the further was able to advantageously achieve a simplification of the production.

(Examples) Examples of the present invention will be shown below to clarify the present invention more specifically, but the present invention should be construed in a limited manner by the description of such examples. It's not a matter of course.

Further, the present invention, in addition to the following embodiments, in addition to the description relating to the specific configuration described above, various modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, It should be understood that modifications, improvements, and the like can be added, and that all such embodiments belong to the scope of the present invention.

First, 10% of chlorinated polyethylene (Cl content = about 45% by weight)
To 0 parts by weight, 1 part by weight of a cross-linking agent, 2,4,6-trimercaptotriazine and 2 parts by weight of 2-mercaptobenzothiazole dicyclohexylamine salt, and lead oxide (PbO) as a cross-linking aid 10 parts by weight of
Similar to the usual rubber kneading operation, knead uniformly in an oven mill (or Bannley mixer) heated to 60 to 80 ° C to form an adhesive composition, and dissolve this composition in toluene. To obtain an adhesive solution.

Then, the surface of the lead plate with a thickness of 0.1 mm is simply degreased with an organic solvent, and then the adhesive solution obtained above is applied and dried, and the adhesive application surface is made to face each other. After stacking two lead plates with a 0.5 mm thick maleic anhydride-modified polyethylene film sandwiched between them, 15
The desired composite electrode material was obtained by thermocompression bonding at a temperature of 0 ° C. for 30 minutes.

In the composite electrode material thus obtained, the adhesive force at the interface between the lead plate and the resin layer is 3 to 5 kg / inch, not only under normal conditions but also under current for charging / discharging. It showed a force, and strong adhesion was confirmed, and no peeling of the adhesive interface between the lead plate and the resin layer was observed even after energization.

Further, in the above experiment, as the vulcanizing agent, 2,4,6-trimercaptotriazine and 2-mercaptobenzothiazole / dicyclohexylamine salt were used in combination, but in the case of using them alone, It was also confirmed that sufficient adhesive force between the lead plate and the resin layer can be secured.

(Effects of the Invention) As is clear from the above description, in the composite electrode material obtained by adhering the lead plate and the olefin resin layer with a predetermined adhesive according to the present invention, extremely strong adhesion Even if the force is realized and it is used as an electrode plate of a lead storage battery, the problem of interfacial delamination due to chemical changes in the electrodes could be advantageously avoided.
Further, even in such a lamination and joining operation of the lead plate and the resin layer, the post-vulcanization method by simply thermocompression bonding can improve the adhesive strength while minimizing the variation in the manufacturing process, and Thus, simplification of the manufacturing process can be advantageously achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a composite electrode material for lead-acid batteries according to the present invention. 2: Lead plate, 4: Olefin resin layer 6: Adhesive layer

Claims (2)

[Claims] 1. A laminated structure in which an olefin resin layer is interposed between lead plates having a predetermined thickness, and the olefin resin layer and the lead plate are chlorinated polyethylene or chlorosulfonated polyethylene. And halogen-containing polyolefin selected from the group consisting of halogenated butyl rubber, 2,4,6-
Lead which is adhered using an adhesive which comprises at least a cross-linking agent consisting of trimercaptotriazine or 2-mercaptobenzothiazole dicyclohexylamine salt or both of them and a lead oxide type cross-linking aid. Composite electrode material for storage batteries. 2. A halogen-containing polyolefin selected from the group consisting of chlorinated polyethylene, chlorosulfonated polyethylene, and halogenated butyl rubber, and 2,4,6-trimercaptotriazine or 2-mercaptobenzothiazole dicyclohexylamine salt, or An adhesive containing at least a cross-linking agent composed of both of them and a lead oxide-based cross-linking aid is applied to the surface of a lead plate having a predetermined thickness, and then the lead plate is applied so that the adhesive-coated surfaces face each other. And a olefin resin layer is formed between the lead plates to form a laminated material, and then the laminated material is thermocompression bonded, which is a method for producing a composite electrode material for a lead storage battery.