JPH01258361A - Lead-acid battery - Google Patents

Abstract

PURPOSE:To ensure the continuity of the effectiveness of lignin as a shrink resistant agent by adding both of a material containing the shrink resistant agent in a hydrocarbon having a low fusing point or a fatty acid and an untreated shrink resistant agent to a negative electrode paste. CONSTITUTION:The powder of a shrink resistant agent (expander) is added to and blended with a saturated hydrocarbon having a low fusion point, an unsaturated hydrocarbon, a saturated fatty acid, an unsaturated fatty acid, wax, paraffin, synthetic resin or materials similar thereto, all in a molten condition, and then solidified. Thereafter, the compound shrink resistant agent so obtained is powdered and an untreated shrink resistant agent is added thereto. The product so obtained is added to a negative electrode paste. In other words, for example, one of a lauric acid having a fusion point of 44 deg.C, a myristic acid having a fusion point of 54 deg.C, a palmitic acid having a fusion point of 63 deg.C a lead stearate having a fusion point of 70 deg.C and the like is heated and melted, and 20wt.% of lignin for a lead acid battery is added thereto as a shrink resistant agent and well blended. Thereafter, the product so obtained is cooled, solidified, and freeze crushed, thereby obtaining a fine particle state. Then, the fine powder so obtained, the untreated shrink resistant agent, barium sulfate and carbon are used as the negative electrode paste.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in lead-acid batteries.

Conventional technology It is said that the modern era is an age of light, thin, short and small size, and lead-acid batteries are no exception; there is a strong demand for smaller and lighter batteries, and diligent efforts are being made to make them lighter and smaller. on the other hand,
Cars, which are the main use for lead-acid batteries, are also becoming smaller and lighter, and with the demand for spacious and comfortable living spaces, the interior of the engine room where lead-acid batteries are placed has become more compact. ing.

Problems that the invention aims to solve As a result of this, the engine room becomes hotter, and lead-acid batteries are placed closer to the engine than before, making lead-acid batteries more prone to being exposed to high temperatures than before. It's coming.

As a result of investigating several batteries that had actually been installed in automobiles and had reached the end of their service life, we found that the deterioration of the negative electrode plate in particular was significant, and the specific surface area of the negative electrode active material decreased, resulting in a significant decline in discharge performance, especially high-rate discharge performance. Understood.

Lignin, which is produced from pulp manufacturing waste, is usually added to the negative electrode active material as an expander along with barium sulfate and carbon, but when the battery becomes high temperature, the effect of the preshrink agent is lost, and the negative electrode active material It is thought that the crystals of metallic lead grow and become coarse, making it impossible to obtain sufficient discharge capacity.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks, and is characterized in that a substance in which an anti-shrink agent is trapped in a low-melting hydrocarbon or fatty acid is added to the negative electrode paste together with an untreated anti-shrink agent. do.

Example Four types of fatty acids having different melting points shown in Table 1 are heated and melted separately, and 20 wt % of lignin for lead-acid batteries is added thereto as an anti-shrink agent and mixed well.

The molten mixtures in Table 1 were cooled and solidified, and then freeze-pulverized to produce fine particulate composite anti-shrink agents A to D. A negative electrode paste was prepared by a conventional method using these composite anti-shrink agents, an untreated anti-shrink agent, barium sulfate, and carbon, and a certain amount of the paste was filled into a lead alloy grid to produce a negative electrode plate. Therefore, an automotive lead-acid battery with a nominal capacity of 28 Ah (5 hR) was assembled using the produced negative electrode plate, and an initial capacity test and a life test were conducted. Table 2 shows the contents of the negative electrode plates of the batteries tested and the initial capacity test results, and Figure 1 shows the results of the life test.

Table 2 In Table 2, test battery No. 001 is a conventional product in which commercially available lignin was added as an anti-shrink agent to the negative electrode paste without any treatment. Nos. 2 to 5 are batteries using negative electrode plates according to the present invention, and Nos. 12 is a composite shrink-preserver made of lauric acid with a melting point of 44°C and lignin made into fine particles by the method described above, and the same amount of untreated lignin as Nos. 011. It was added. The same was true for NO, 3 to 5, and a composite anti-shrink agent was used together, but NO,
4 is ^, 8. C and untreated lignin, N085 is A, B,
Two to four types of composite antishrink agents, such as C and D and untreated lignin, are used in combination with untreated lignin.

The initial capacity of both batteries was almost the same and there was no significant difference. This is because the discharge was carried out at a temperature below the melting point of the fatty acid used, so the added composite anti-shrink agent had no effect, and only the untreated lignin contributed to the discharge.

Figure 1 shows the results of the life test.The test conditions were 20A discharge.
The test temperature was increased by 10°C from 40°C every 50 cycles.

The capacity during the cycle was confirmed by discharging at 150 A at -15°C. The reason why the capacity was confirmed using high rate discharge in this way is that the influence of the negative electrode plate is easier to understand as the discharge rate is higher.

During the first 50 cycles conducted at 40° C., the high rate discharge capacity of all batteries decreased by about 20%, and the effect of adding the composite antishrink agent has not yet appeared. When the test temperature was increased to 50° C. for 50 to 100 cycles, the capacity of conventional product N001 decreased to 60%. On the other hand, No. 12 to 5 of the products of the present invention
The discharge capacity increased and then decreased, but the capacity remained almost unchanged between 50 and 100 cycles. During this period, composite anti-shrink agent A treated with lauric acid having a melting point of 44° C. acts effectively. Thereafter, as a result of increasing the battery temperature by 10° C. every 50 cycles, the capacity changed as shown in FIG. 1, and the capacity decrease of the conventional product N011 was remarkable.

On the other hand, in the product of the present invention, the composite anti-shrunk agent acts effectively when cycled at a temperature higher than the melting point of the fatty acid used, and as a result of increasing the temperature to 80'C, four types of composite anti-shrunk agents, A, B, C, and D were detected. The N005 battery with the addition of 20% of the total capacity showed the best capacity change.

Effects of the Invention As described above, the present invention has the effect of melting the fatty acid in the composite anti-shrink agent added as the battery temperature increases.
The effect of lignin as an anti-shrink agent could be sustained. If a composite anti-shrink agent treated with fatty acids having different melting points is used alone or in combination depending on the usage conditions of the battery, lead-acid batteries exhibiting various high-temperature resistance properties can be obtained, which is of great industrial value. Although saturated fatty acids with different melting points were used in this example,
Unsaturated fatty acids, hydrocarbons, higher alcohols, and waxes.

Any substance that melts as the battery temperature rises and is harmless to the battery, such as paraffin or synthetic resin, can be used.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram comparing the life performance of the lead-acid battery of the present invention with that of a conventional product. Threat 1 drawing~゛1 Luk (No say no to N5 0 50 100 150 200
25 Q4 Ai 22 1 (Written procedural amendment) % formula % 2. Name of the invention 4. Date of amendment order (shipment) June 28, 1988 5. Drawing subject to amendment (Fig. 1) ). street. Qi 1st exam, exam friend? 1 full daring

Claims (1)

[Claims] 1. Melted low melting point saturated hydrocarbons, unsaturated hydrocarbons, saturated fatty acids, unsaturated fatty acids, wax, paraffin,
It is characterized by adding powdered shrink-proofing agent (expander) to synthetic resins or similar substances thereof, and adding a composite shrink-proofing agent (expander), which is made from a solid solid after mixing and solidifying into powder, and an untreated shrink-proofing agent to the negative electrode paste. lead-acid battery.