TW201424084A - Electrolyte additive for lead acid battery - Google Patents

Abstract

The present invention relates to an electrolyte additive of lead acid battery, which contains silica particles having two different particle with diameters between 2~40 nanometers, and each of the two types of silica particles with different particle diameters having content between 30~70 wt.% and as 100 wt.% in total. The silicon particles may be the colloidal silica, and may be 0.1~3 wt.% of the total weight of lead acid battery. By adding electrolyte additive containing silica particles in different particle diameters, the present invention may reduce the stratifying level and fluidity of electrolyte, so as to enhance service life of lead acid battery.

Description

Electrolyte additive for lead-acid battery

The invention relates to an electrolyte additive for a lead-acid battery, in particular to an electrolyte additive for mixing at least two kinds of cerium salt particles of different particle diameters. The additive of the invention can reduce the degree of stratification of the lead acid battery electrolyte, prolong the gel time of the colloidal electrolyte, and improve the charge and discharge performance of the lead acid battery, thereby prolonging the service life of the battery.

In recent years, lead-acid batteries have developed into a widely used storage power device. When discharging, the lead on the positive and negative electrodes and the lead on the negative electrode are converted to lead sulfate. The discharge reaction is as follows:

PbO ₂ + Pb +2H ₂ SO ₄ → 2PbSO ₄ +2H ₂ O

Conventional lead-acid battery electrolytes have many electrical disadvantages, such as high internal resistance, low capacitance, hydration stratification of the electrolyte, and short battery life. Currently, although there are additives for improving the storage performance of lead-acid batteries, the effect is It is not obvious. Traditionally, lead-acid battery electrolyte additives are various. Most lead-acid battery electrolyte additives contain alkali metal and alkaline earth metal sulfate, phosphoric acid, cobalt sulfate, cadmium sulfate, stannous sulfate, copper sulfate, zinc sulfate, nickel sulfate, Aluminum sulfate, carbon suspension, fumed silica, and colloidal silica of a single particle size, but have limited storage capacity for lead-acid batteries.

In addition, the use of a single particle size colloidal ceria solution as an additive to a lead-acid battery electrolyte can cause a number of disadvantages, such as: small particle size colloidal ceria electrolyte additives in lead-acid battery production processes, often lead acid The battery electrolyte solidifies rapidly; the large particle size colloidal cerium oxide additive slows the solidification rate of the lead-acid battery electrolyte. To make the gel level of the lead-acid battery electrolyte reach the production process, the colloidal cerium oxide must be increased. The concentration, which in turn leads to an increase in production costs.

U.S. Patent Publication No. 2005/0042512 discloses a lead-acid battery having an electrolyte solution prepared by containing sulfuric acid and barium salt particles having a specific gravity of 1.250 to 1.280, wherein the content of the barium salt particles accounts for about 2 From about 1% by weight to about 15% by weight, and at least 10% by weight of the cerium salt particles are used in the never-dried precipitated silica. Further, U.S. Patent No. 4,317,872 discloses an electrolyte positioning method which utilizes sulfuric acid and cerium salt particles to gel the electrolyte to localize it. However, this gelled electrolyte has many disadvantages such as high internal resistance, low capacitance, and shorter cycle life than conventional lead-acid batteries. In addition, since the gelled electrolyte may shrink, it is liable to cause problems such as poor contact between the electrolyte and the plates. Moreover, the general gelled electrolyte has high viscosity, is not easy to be filled in the battery container, and is not easily penetrated into the capillary holes in the electrode plate to saturate it. Therefore, the lead acid battery has difficulty in the production process.

As described above, it is known that a lead-acid battery having a gelled electrolyte still has a problem of poor electrical function and a problem that the gelled electrolyte has a high viscosity and is difficult to be filled in a battery container. Therefore, the present invention provides a lead-acid battery electrolyte additive. Improve the above problems.

The main object of the present invention is to provide an electrolyte additive for a lead-acid battery to solve the problem that the prior art cannot overcome.

In order to achieve the above object, the present invention provides an electrolyte additive for a lead-acid battery, comprising two different particle size strontium salt particles having a particle diameter of between 2 and 40 nm, and the two different particle sizes. The strontium salt particles each have a content of between 30 and 70% by weight and a total of 100% by weight. In addition, the particle sizes of the two different particle size strontium salt particles are selected from the group consisting of 2 nm, 5 nm, 8 nm, 10 nm, 15 nm, and 35 nm. Two different particle sizes and their contents are 30% and 70% by weight, respectively. Preferably, in the two different particle size strontium salt particles, the large particle size strontium salt particles content is 30% by weight, and the small particle size strontium salt particles content is 70% by weight. Further, the cerium salt particles are preferably colloidal silica and constitute 0.1 to 3% by weight based on the total weight of the electrolyte of the lead-acid battery.

The present invention further provides an electrolyte for a lead-acid battery comprising sulfuric acid having a specific gravity of 1.28 to 1.34 g/cm ³ and an electrolyte additive of the aforementioned lead-acid battery.

Lead-acid batteries have experienced multiple times of charge and discharge and increased use time. Lead-acid batteries have problems such as attenuation of storage performance and increase of internal resistance. When charging, the charging voltage will rise sharply and the charging current will drop, resulting in lead storage batteries. Unable to return to the original stored energy. Therefore, the present invention achieves the effect of improving the storage capacity of the lead-acid battery and increasing the cycle life of the lead battery by using the electrolyte additive of the colloidal cerium oxide having a low concentration and a low viscosity.

The invention adds an electrolyte additive composed of two different particle size strontium salt particles having a particle diameter of between 2 and 40 nm, wherein the two different particle size strontium salt particles are preferably It is colloidal cerium oxide, which reduces the degree of stratification and fluidity of lead-acid battery electrolyte, and achieves a high solidification strength colloidal electrolyte with a low concentration of cerium oxide, thereby making the lead acid battery life of adding this agent improve. In addition, the use of colloidal cerium oxide in the production of lead-acid batteries does not cause dust to be produced, and it does not pose a health hazard to workers.

In addition, the colloidal cerium oxide electrolyte additive containing different particle diameters is pre-mixed with the mixing ratio and concentration of colloidal cerium oxide of different particle sizes in the additive, and then supplied to the lead acid battery electrolyte. Can reduce the production cost of lead-acid batteries.

The electrolyte additive for preparing the lead-acid battery of the present invention may be a conventional mixing machine such as a Cowless dissolver, a propeller stirrer or the like, and the colloidal cerium oxide used in the present invention. Commercially available products can be used as the solution, for example, AkzoNobel under the trade names BINDZILR GB1000, GB2000, GB 3000 or LEVASILR 300/30, 200/40.

(Comparative Examples 1 to 6)

The colloidal cerium oxide having a particle diameter of 2 nm, 5 nm, 8 nm, 10 nm and 15 nm is respectively added to the electrolyte of the lead-acid battery, and diluted with water to a predetermined concentration of strontium salt particles, wherein the electrolysis The liquid contains sulfuric acid having a specific gravity of 1.28 to 1.34 g/cm ³ . When the electrolyte reaches a minimum solidification, the content of SiO ₂ in the electrolyte is measured. Based on the total weight of the electrolyte, it was found that the SiO ₂ accounted for 0.1% to 3.5% by weight, and the minimum solidification time of the electrolyte was between 5 and 90 minutes or more than 180 minutes. In addition, 35 nm of colloidal cerium oxide is added to the lead acid battery electrolyte, the electrolyte has a minimum clotting time of more than 180 minutes, and the SiO ₂ content of the electrolyte is based on the total weight of the electrolyte. As a result, it was found that the SiO ₂ accounted for more than 3.5% by weight.

(Example 1)

Two kinds of colloidal ceria of different particle sizes of 2 nm and 5 nm were uniformly mixed at 70%:30% by weight using a Coles high-speed disperser, and the mixing speed was adjusted to obtain a uniformly mixed solution. And prevent the speed of agglomeration or sedimentation. The resulting additive solution is then added to the lead acid battery electrolyte and diluted with water to a predetermined cerium salt particle concentration, wherein the electrolyte contains sulfuric acid having a specific gravity between 1.28 and 1.34 g/cm ³ . When the electrolyte reaches a minimum solidification, the content of SiO ₂ in the electrolyte is measured. Based on the total weight of the electrolyte, it was found that the SiO ₂ accounted for 1% to 1.5% by weight, and the minimum solidification time of the electrolyte was between 10 and 15 minutes.

(Example 2)

In the same manner as in Example 1, except that 70%: 30% by weight of 2 nm and 8 nm of two different particle size colloidal ceria were used to prepare an additive solution, and lead-acid battery electrolysis was added. In the liquid. Based on the total weight of the electrolyte, it was found that the SiO ₂ accounted for 1% to 1.5% by weight, and the minimum solidification time of the electrolyte was between 25 and 30 minutes.

(Example 3)

In the same manner as in Example 1, except that 70%: 30% by weight of 2 nm and 10 nm of two different particle size colloidal ceria were used to prepare an additive solution, and lead-acid battery electrolysis was added. In the liquid. Based on the total weight of the electrolyte, it was found that the SiO ₂ accounted for 1% to 1.5% by weight, and the minimum solidification time of the electrolyte was between 30 and 35 minutes.

(Example 4)

In the same manner as in Example 1, except that 70%: 30% by weight of 5 nm and 8 nm of two different particle size colloidal ceria were used to prepare an additive solution, and lead-acid battery electrolysis was added. In the liquid. Based on the total weight of the electrolyte, it was found that the SiO ₂ accounted for 1% to 1.5% by weight, and the minimum solidification time of the electrolyte was more than 120 minutes.

The results of Comparative Examples 1 to 6 and Examples 1 to 4 of the lead-acid battery electrolyte are shown in Table 1.

Table 1 Comparison of the minimum solidizable SiO ₂ content of lead-acid battery electrolyte and time

*In the case of the same pH value ** at the same pH value and SiO ₂ content (%)

(Examples 5 to 12)

Working in the same manner as in Example 1, two different particle size colloidal cerium oxides of 2 nm and 5 nm were respectively 10%: 90%, 20%: 80%, 30%: 70%, 40%: 60%, 50%: 50%, 60%: 40%, 80%: 20%, 90%: 10% by weight ratio is uniformly mixed to prepare an additive solution, and added to the lead acid battery electrolyte. The minimum settable time of the electrolyte was measured, and the result is shown in Fig. 1. When one of the particle diameter ratios is less than 30%, the electrolyte additive has no significant influence on the overall performance of the electrolyte.

As shown in FIG. 2, according to Embodiments 1 to 4 of the present invention, after adding a lead-acid battery electrolyte additive provided by the present invention to a lead-acid battery, the lead-acid battery contains different particle sizes under 20 discharge cycle tests. The lead-acid battery electrolyte of the strontium salt particles has a better discharge capacity.

It can be seen from the results of the above examples that by adding the electrolyte additive containing the cerium salt particles of different particle sizes provided by the present invention, the degree of stratification and fluidity of the electrolyte can be reduced, thereby improving the service life of the lead-acid battery.

Fig. 1 is a time chart of the lowest solidification time of the electrolyte when the particle size of 2 nm and 5 nm of cerium oxide are mixed in different ratios.

2 is a graph showing a comparison of discharge capacities of a lead acid battery to which an electrolyte additive of the present invention is added in 20 discharge cycles.

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Claims (7)

An electrolyte additive for a lead-acid battery, comprising two different particle size strontium salt particles having a particle size of between 2 and 40 nanometers, and the two different particle size strontium salt particles each having a content of 30 Between ~70% by weight and a total of 100% by weight. For example, in the electrolyte additive of claim 1, the particle size of the two different particle size strontium salt particles is selected from the group consisting of 2 nm, 5 nm, 8 nm, 10 nm, 15 nm, and There are two different particle sizes in the group consisting of 35 nm, and their contents are 30% and 70% by weight, respectively. The electrolyte additive according to claim 2, wherein the content of the large particle size cerium salt particles is 30% by weight, and the content of the small particle size cerium salt particles is 70% by weight. The electrolyte additive according to any one of claims 1 to 3, wherein the cerium salt particles are colloidal silica. The electrolyte additive according to any one of claims 1 to 3, wherein after the electrolyte additive is added to the lead acid battery electrolyte, the cerium salt particles are based on the total weight of the electrolyte. The system accounts for 0.1 to 3% by weight. An electrolyte for a lead-acid battery comprising sulfuric acid having a specific gravity of 1.28 to 1.34 g/cm ³ and an electrolyte additive of any one of claims 1 to 5. The electrolyte of claim 6, wherein the electrolyte additive accounts for 0.1 to 3% by weight based on the total weight of the electrolyte.