Lead-acid batteries and methods for preventing corrosion of lead-acid battery terminals.

Abstract

DEPCT63 A lead-acid battery that is designed to prevent oxidation at each terminal. High heat and humidity environments, combined with other factors, can prevent discoloration. From the chemical reaction of the anti-corrosion material with each end electrode. In a lead-acid battery, which consists of two main battery cells and three terminal terminals, there are electrodes. The positive and negative terminals protruding from the main battery are covered by two enclosed terminal covers. The pine resin acts as an anti-rust agent. -----------------------------------------------------------

Description

Lead-acid battery and method for preventing rust on terminals of lead-acid battery

[0001] The present invention relates to a lead-acid battery and a method for preventing rust on terminals of the lead-acid battery.

[0002] A lead-acid battery including a battery case and positive and negative terminals exposed outside the battery case is known. Terminals of this type are formed of a metal material such as a lead alloy and have a shape according to specifications. For example, in a lead-acid battery mounted on a motorcycle, each terminal is a box-shaped terminal (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-283825

[0004] By the way, when a lead-acid battery is stored in a high-temperature and high-humidity environment corresponding to a tropical region, it has been found that lead oxide may form on the surface of each lead-alloy terminal, and the terminal may turn white. When a known rust preventive was applied to each terminal to avoid oxidation of the surface of each terminal, the surface of each terminal turned black and the metallic luster was not maintained. The reason is considered to be that the mineral oil, rust inhibitor, etc. contained in the known rust preventive chemically reacted with the terminal.

[0005] Therefore, an object of the present invention is to prevent oxidation of each terminal even in a high-temperature and high-humidity environment and also to prevent discoloration due to a chemical reaction between the material used for rust prevention and each terminal. Note that a lead-acid battery having a terminal structure with low electrical resistance by applying a flux agent (organic rosin) to at least a part of the surface of a core made of copper or a copper alloy and suppressing a decrease in adhesion between the core and the lead alloy constituting the main body of the terminal post has been proposed (see Japanese Patent No. 4876323), but the object, configuration, and effect are completely different from those of the present invention. That is, the present invention is not simply a transfer of known technology but is based on new findings.

[0006] This specification includes all the contents of Japanese Patent Application No. 2018-118483 filed on June 22, 2018. To solve the above-described problems, the present invention provides a lead-acid battery including a battery body and positive and negative terminals exposed outside the battery body, wherein each terminal including the positive terminal and the negative terminal is covered with rosin to prevent rust.

[0007] In the above configuration, the terminal is provided with a connecting portion that is joined to an electrode plate located inside the battery body, and the entire terminal, including the connecting portion, may be covered with rosin.

[0008] Furthermore, in the above configuration, the terminal may be a box-shaped terminal with a hollow box-shaped portion exposed to the outside of the battery body.

[0009] Furthermore, the present invention relates to a method for preventing corrosion of terminals of a lead-acid battery, which comprises a battery body and positive and negative terminals exposed outside the battery body, characterized in that rosin is used as a corrosion inhibitor for each terminal, which consists of the positive and negative terminals.

[0010] Furthermore, in the above configuration, the terminals are provided with connecting portions that are joined to electrode plates arranged inside the battery body, and each terminal and the battery body are integrated by insert molding. Before joining the connecting portions to the electrode plates and before the insert molding, the entire terminals may be covered with rosin.

[0011] Furthermore, in the above configuration, each terminal may be covered with rosin by immersing it in a liquid containing rosin and then drying it.

[0012] According to the present invention, oxidation of each terminal can be prevented even in high-temperature and high-humidity environments, and discoloration due to chemical reactions between the rust-preventive material and each terminal can also be prevented.

[0013] Figure 1 is a perspective view of a lead-acid battery according to an embodiment of the present invention. Figure 2 is a diagram showing the terminals together with the surrounding configuration. Figure 3 is a diagram showing an example of the manufacturing process.

[0014] An embodiment of the present invention will be described below. Figure 1 is a perspective view of a lead-acid battery according to an embodiment of the present invention. The lead-acid battery 1 comprises a rectangular parallelepiped battery body 2 and a plurality of terminals 3 exposed to the outside of the battery body 2. The battery body 2 comprises a box-shaped battery case 2A whose interior is divided into a plurality of chambers, each chamber having a plurality of electrode plates, and a lid 2B that covers the upper opening of the battery case 2A. The battery case 2A and the lid 2B are made of a resin material such as polypropylene (PP).

[0015] Multiple terminals 3 consist of positive terminals and negative terminals. In this embodiment, the positive terminals and negative terminals are formed from the same component. However, the positive terminals and negative terminals may have different shapes or other features. This lead-acid battery 1 is a lead-acid battery for motorcycles, and the terminals 3 are formed as hollow box-shaped terminals. However, this lead-acid battery does not have to be for motorcycles, and may be a battery used for various purposes. Also, the shape of the terminals 3 may be changed as appropriate according to the specifications.

[0016] Figure 2 shows the terminal 3 along with its surrounding configuration. The terminal 3 is integrally provided with a connecting portion 4 that is joined to multiple pole plates of the same polarity, and is also called a bushing terminal. This connecting portion 4 has a pole post 5 extending from the terminal 3 and a strap 6 that is joined to the pole post 5 on the side opposite to the terminal 3. The terminal 3, pole post 5 and strap 6 are integrally formed by casting using a metal material such as a lead alloy. In addition, multiple flange portions 5A are provided around the pole post 5 at the locations corresponding to the pole post 5, and a cover 2B is integrated into the region corresponding to these flange portions 5A by insert molding.

[0017] Incidentally, the inventors' studies revealed that if a rust inhibitor is not applied to terminal 3, and the lead-acid battery 1 is stored in a high-temperature, high-humidity environment equivalent to a tropical region, the surface of terminal 3 may oxidize, and the terminal may turn white due to lead oxide. To address this, when a known rust inhibitor was applied to terminal 3, it was found that the rust inhibitor chemically reacted with the metal of terminal 3, causing terminal 3 to turn black or losing its metallic luster. The inventors diligently studied materials that could prevent the whitening and blackening of terminal 3 due to oxidation, and as a result, they found that covering terminal 3 with rosin, which is not generally used as a rust inhibitor, prevents the whitening and blackening of terminal 3.

[0018] In this embodiment, the entire terminal 3, including the connecting portion 4, is covered with rosin to prevent whitening and blackening of the terminal 3 even in high-temperature and high-humidity environments. Here, the rosin can be any rosin-based resin whose main component is rosin acid (such as abietic acid, palastic acid, or isopimal acid), such as tall rosin, gum rosin, and wood rosin. Rosin is also called corohony or corohonium.

[0019] Known uses of rosin include its application as a flux to improve adhesion between the terminal 3 and the lid 2B of the battery case 2A during insert molding of the terminal 3 and the lid 2B of the battery case 2A (e.g., Japanese Patent Publication No. 2001-504631), and its application as a flux to improve adhesion between the electrode posts 5 of the battery case 1 and the lead alloy during casting (e.g., Japanese Patent Publication No. 4876323). In this embodiment, the entire terminal 3 is covered with rosin before insert molding of the terminal 3 and the lid 2B of the battery case 2A, and before joining the connection portion 4 of the terminal 3 to the electrode plate, thereby using the rosin as both a rust inhibitor and a flux to improve adhesion between the parts.

[0020] Figure 3 shows an example of the manufacturing process from the production of the terminal 3 to the shipment of the lead-acid battery 1. As shown in Figure 3, first, as step S1, a terminal manufacturing process is carried out in which the terminal 3 is manufactured by casting. In this way, the terminal 3 is manufactured integrally with the connecting part 4. A wide range of known methods can be applied to the method of manufacturing the terminal.

[0021] Next, in step S2, the terminal 3 is immersed in an alcohol solution containing a mixture of powdered rosin and alcohol, and then dried in a rosin immersion and drying process. This allows the entire terminal 3 to be easily covered with rosin, even if it is a box-shaped terminal with a complex shape. The time and temperature conditions required for immersion and drying can be set as appropriate. The concentration of the alcohol solution, which is a mixture of rosin and alcohol solution, is preferably 1% to 5%. If the concentration is less than 1%, the effect of preventing oxidation of the terminal is low. If it exceeds 5%, the effect will saturate, so considering the cost, 5% or less is preferable.

[0022] Next, in step S3, a battery assembly process is carried out to assemble the lead-acid battery 1. This process includes known steps such as joining the terminals 3 and the electrode plates using a known method such as the cast-on strap method, and insert molding the terminals 3 into the lid 2B of the battery case 2A, and is carried out until the final assembly of the lead-acid battery 1 is complete. After that, in step S4, the lead-acid battery 1 is transported to the packaging and shipping inspection line. This allows for packaging of the lead-acid battery 1 and various inspections for shipping.

[0023] In this way, since terminals 3 are covered with rosin before the battery assembly process, the process of applying rosin to terminals 3 during the battery assembly process is unnecessary, and the process of covering terminals 3 with rosin is completed in one step. Furthermore, the rosin immersion and drying process helps to avoid areas where rosin is missed when applying it to terminals 3.

[0024] The lead-acid battery 1 manufactured as described above will be designated as Example 1 and compared with Comparative Examples 1 and 2. Comparative Example 1 is a lead-acid battery in which rosin and rust inhibitor are not applied to terminal 3, and Comparative Example 2 is a lead-acid battery in which a known rust inhibitor is applied to terminal 3. The rust inhibitor used in Comparative Example 2 consists of mineral oil, a rust inhibitor, and a petroleum-based solvent.

[0025] Each lead-acid battery from Example 1 and Comparative Examples 1 and 2 was packaged in a cardboard box and stored in an environment of 80 degrees Celsius for 7, 12, and 21 days, respectively. Then, each lead-acid battery was stored in an environment of -10 degrees Celsius for one day. After that, the box was opened for a predetermined time to moisten it (making it damp), and then the box was closed and covered with plastic wrap. An experiment was conducted in which the terminals 3 were observed after one week in an environment of normal temperature. The results of this experiment are shown in Table 1.

[0026]

[0027] As shown in Table 1, in Comparative Example 1, the entire surface of terminal 3 of the lead-acid battery turned white and oxidation progressed under all conditions. In Comparative Example 2, terminal 3 partially turned white under each of the 21-day storage conditions. Furthermore, in Comparative Example 2, the metallic luster of terminal 3 was not maintained under any conditions and it became dull. In contrast, in Example 1, no whitening of terminal 3 was observed under any conditions, and the metallic luster of terminal 3 was maintained. This effect may be due to the surfactant action of rosin.

[0028] Furthermore, the inventors confirmed that even when the surface of terminal 3 of lead-acid battery 1 was polished and the terminal 3 was covered with rosin, no whitening of terminal 3 was observed, and the metallic luster of terminal 3 was maintained. In other words, even in a state where polishing would have made whitening and tarnishing more likely, covering with rosin was able to sufficiently suppress whitening and tarnishing.

[0029] As explained above, each terminal 3, consisting of the positive and negative terminals, is covered with rosin for rust prevention. This prevents oxidation of each terminal even in high-temperature and high-humidity environments, and also prevents discoloration due to chemical reactions between the rust-preventive material and each terminal. In other words, by finding a use for rosin as a rust inhibitor, a suitable dust-proofing method for the terminals 3 of the lead-acid battery 1 can be provided.

[0030] Furthermore, since the entire terminal 3, including the connecting portion 4 that is joined to the electrode plate, is covered with rosin, covering the terminal 3 with rosin before the battery assembly process eliminates the need to apply rosin to the terminal 3 during the battery assembly process, while allowing the rosin to be used as both a rust inhibitor and a flux to improve the adhesion of each part.

[0031] Furthermore, since the part of terminal 3 that is exposed to the outside of the battery body 2 is a hollow box-shaped terminal, the box-shaped terminal can be easily covered with rosin by employing a simple process such as immersing the box-shaped terminal in a liquid containing rosin and drying it.

[0032] The embodiments described above represent only one aspect of the present invention and can be modified and applied as needed without departing from the spirit of the invention. For example, although the present invention has been described in relation to the lead-acid battery 1 and the method for preventing corrosion of the terminals of the lead-acid battery 1 shown in Figure 1, it is not limited to this and may be applied to other known lead-acid batteries and methods for preventing corrosion of the terminals of lead-acid batteries. Furthermore, the method of covering each terminal with rosin is not limited to the method described above. For example, a method of spraying rosin in spray form onto each terminal 3 may also be used.

[0033] 1. Lead-acid battery 2. Battery body 2A. Battery case 2B. Cover 3. Terminals 4. Connection part 5. Poles 5A. Flange 6. Strap

Claims

DEPCT631. A lead-acid battery consisting of a main battery and terminals with positive and negative electrodes protruding from the main battery, which is characterized by each terminal with such positive and negative electrodes being covered with rosin and treated as an anti-corrosion agent.

2. A lead-acid battery specified in Representation 1, which is characterized by the connection of the terminals being attached to electrode plates arranged inside the main battery and the entire terminal, including the connection, being covered with rosin.

3. A lead-acid battery specified in Representation 1 or 2, which is characterized by the terminals protruding from the main battery being hollow box-shaped terminals.

4. An anti-corrosion method for the terminals of a lead-acid battery consisting of a main battery and terminals with such positive and negative electrodes protruding from the main battery, which is characterized by the use of rosin as an anti-corrosion agent for each terminal with such positive and negative electrodes. 5.The method for corrosion protection of lead-acid battery terminals specified in claim 4 is characterized by the connection of the terminals being welded to electrode plates arranged within the main battery and, together with each terminal and the main battery, being made as a single piece by insert forming, and before welding the connection to the electrode plates, and together with before the insert forming, the entire terminal is covered with rosin.

6. The method for corrosion protection of lead-acid battery terminals specified in claim 4 or 5 is characterized by the immersion of the terminals in a liquid containing rosin and drying, and then covering each terminal with rosin.