KR100832375B1 - A Gel electrolyte of Long Life Valve regulated sealed lead acid battery for Solar and Wind Power - Google Patents

Abstract

In the present invention, the gel electrolyte is composed of 75-79.2 wt% H ₂ O, 15-19.2 wt% SiO ₂ , 0.5-0.6 wt% Na ₂ SO ₄ , 5-6 wt% H ₃ PO ₄ , and 0.3 Long time use by adding ~ 0.7wt% sodium silicate, 0.2 ~ 0.5wt% sodium carboxymethyl cellulose or 0.1 ~ 0.3wt% sodium silicate and 0.2 ~ 0.5wt% sodium carboxymethyl cellulose Edo prevents the drying of the gel due to moisture evaporation, so that the life of the battery can be extended.

Solar, wind power, battery, liquid, gel, storage battery, electrolyte, dry

Description

Gel electrolyte of long life valve regulated sealed lead acid battery for solar and wind power generation

1 is a graph according to a conventional electrolyte

2 is a graph according to the sealed lead-acid battery of the present invention

The present invention relates to a gel electrolyte of a VRLA (valve regulated lead acid battery) developed for application in applications requiring long life, such as for photovoltaic power generation / wind power generation, emergency power, etc., to achieve long life gel It is an improvement of the gel electrolyte which suppresses dry out of the electrolyte.

Generally, the lead-acid battery for photovoltaic power generation can be largely classified into an open lead-acid battery using sulfuric acid electrolyte as a liquid and a sealed type absorbing sulfuric acid electrolyte in AGM or GEL.

First, an open lead-acid battery is used by dividing into a paste type and a tubular type according to a method of forming a positive electrode plate.

Since these batteries have to measure and manage the amount of electrolyte at all times, the battery has a transparent structure. These batteries must periodically measure the specific gravity and temperature of the electrolyte and replenish the purified water or the electrolyte.

Therefore, in order to facilitate such periodic monitoring, a batch maintenance device, a voltage and a liquid level monitoring device may be additionally installed and operated.

In addition, these accumulators are classified into two types: an exhaust plug filter to prevent the discharge of sulfuric acid, and a recovery catalyst field to return hydrogen and oxygen generated during charging to water.

Next, the sealed lead acid battery (VRLA) is divided into an AGM type battery using a glass fiber separator to absorb an electrolyte and a gel type battery using a gel electrolyte, unlike the structure of an open lead acid battery.

The gel electrolyte used in the gel type battery is injected into the liquid phase and solidified in the battery when injected into the battery.Therefore, there is no leakage of electrolyte when the battery breaks down, and oxygen and hydrogen generated in the battery by oxygen recombination are recombined and reduced to water to lose water in the electrolyte. It is a gel electrolyte of a maintenance-free battery that minimizes the need for replenishment of purified water during use of the battery.

In general, open lead-acid batteries having a large amount of a flowing electrolyte, in use, especially in a vibration or inclined place, the leakage of the dilute sulfuric acid, which is an electrolyte, has the drawback to corrode surrounding equipment or pollute the environment.

The sealing of lead-acid battery is to induce the fluidization of the separator by injecting silica sand into the electrolyte in the form of sol and absorbing the electrolyte solution. Was attempted as a sealed battery.

However, these batteries could not prevent the decrease of electrolyte during overcharging even though they had a liquid-free structure.

In order to seal the lead-acid battery, internal gas (oxygen and hydrogen gas) must be recombined in the battery to prevent the exhaustion of the electrolyte, and lead sulfate is reduced to lead on the surface of the cathode.

At the time of discharge, both electrodes become lead sulfate (PbSO ₄ ). This is represented by the general scheme as follows.

Anode Reaction: PbO ₂ + 4H ⁺ + 2e ⇔ Pb ² + 2H ₂ 0 ------------- (1)

⇔

-------------(2)

⇔

-------------(2)

⇔

-------------------------(3)Cathodic Reaction:

⇔

------------------------- (3)

⇔

-----------(4)

⇔

-----------(4)

⇔

---(5)Overall response:

⇔

--- (5)

As the charging process proceeds, there is no lead sulfate to be reduced to lead at the cathode, and eventually, the electrolyte is electrolyzed to generate hydrogen.

In addition, as the charging progresses considerably at the positive electrode, that is, when the battery voltage rises near the full charge and becomes higher than the gas generation voltage of the battery, an overcharge reaction starts, and water is decomposed to generate oxygen at the positive electrode and hydrogen at the negative electrode. .

Meanwhile, the overcharge reaction scheme is as follows.

Anode _{reaction: H 2 O → 1 / 2O} 2 + 2H + + 2e - ----------- (6)

Cathode ^{reaction: 2H + + 2e - → H} 2 -------------------- (7)

Total reaction: H ₂ O → H ₂ + 1 / 2O ₂ ------------------ (8)

As lead-acid batteries are charged, the charging efficiency of the plates decreases, so overcharging is inevitable to fully charge the batteries.

In the case of a sealed battery, since there is no excess electrolyte, the loss of the electrolyte causes a decrease in battery capacity according to Equation (5), which causes a huge loss in the life of the battery.

Recently, gel-type batteries have become mainstream due to the advantages of maintenance and installation as described above. However, gel-type batteries have limited electrolytes compared to liquid-type batteries, and the gels dry out due to hydrolysis of water during overcharging. There is a shortcoming.

The present invention is to solve the above-mentioned shortcomings, improve the case of a sealed lead-acid battery by adding an additive to the gel electrolyte to suppress the drying of the gel by moisture evaporation to increase the life of the storage battery The present invention provides a gel electrolyte for a long life sealed lead acid battery for power generation.

In order to achieve the above object, the gel electrolyte of a long life sealed lead-acid battery for solar / wind power generation according to the present invention has a basic composition of H ₂ O of 75 to 78.1 wt%, and SiO ₂ of 15 to 19.2 wt%. , 0.5 to 0.6 wt% Na ₂ SO ₄ , characterized in that consisting of 5 to 6 wt% H ₃ PO ₄ .

In addition, the present invention is characterized in that the addition of 0.3 ~ 0.7wt% sodium silicate to the gel electrolyte.

In addition, the present invention is characterized in that 0.2 to 0.5wt% of sodium carboxymethyl cellulose is further added to the gel electrolyte.

In addition, the present invention is characterized in that the addition of 0.1 ~ 0.3wt% sodium silicate and 0.2 ~ 0.5wt% sodium carboxymethyl cellulose to the gel electrolyte.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention suppresses the cathode reaction during the overcharge reaction in order to prevent the loss of the electrolyte solution, and oxygen from the anode reaction is recombined (Oxygen recombination) at the cathode to reduce it back to water.

The principle of oxygen recombination, the basic concept of sealing lead-acid batteries, can be expressed by the following equation.

O ₂ (gas) + 2Pb ⇔ 2PbO ------------------- (9)

2PbO + 2H ₂ SO ₄ ⇔ 2PbSO ₄ + 2H ₂ O ---------- (10)

2PbSO ₄ + 4H ⁺ + 4e ⇔ 2Pb + 2H ₂ SO ₄ -------- (11)

Total reaction: O ₂ + 4H ⁺ + 4e ⇔ 2H ₂ O ---------- (12)

The basic composition of the gel electrolyte includes 75-79.2wt% H ₂ O, 15-19.2wt% SiO ₂ , 0.5-0.6wt% Na ₂ SO ₄ , 5-6wt% H ₃ PO ₄ It is done by

Thus, the present invention can achieve the gel electrolyte in the above configuration to suppress the drying of the gel by water evaporation can be achieved by the three examples as shown in the following table.

TABLE 1

division H ₂ O SiO ₂ Na ₂ SO ₄ H ₃ PO ₄ Sodium silicate Remarks Composition (wt%)  75-79.2  15 ~ 19.2  0.5 to 0.6  5 ~ 6  0.3 ~ 0.7

TABLE 2

 division H ₂ O SiO ₂ Na ₂ SO ₄ H ₃ PO ₄ Sodium carboxymethyl cellulose  Remarks Composition (wt%)  75-79.2  15 ~ 19.2  0.5 to 0.6  5 ~ 6  0.2-0.5

TABLE 3

 division H ₂ O SiO ₂ Na ₂ SO ₄ H ₃ PO ₄ Sodium carboxymethyl cellulose Sodium silicate Composition (wt%)  75-79.2  15 ~ 19.2  0.5 to 0.6  5 ~ 6  0.1-0.3  0.2-0.5

According to the present invention, as shown in Tables 1 to 3 above, an additional additive may be added to the gel electrolyte to suppress the drying of the gel due to hydrolysis of water. For example, 0.3 to 0.7 wt.% In the basic composition of the gel electrolyte. Add sodium silicate in the range of%, add 0.2-0.5 wt% of sodium carboxymethyl cellulose to the base composition of the gel electrolyte, or 0.1-0.3 to the base composition of the gel electrolyte Wt% sodium silicate and 0.2-0.5 wt% sodium carboxymethyl cellulose may be further added.

As such, when the additive is further added to the basic composition of the electrolyte, it can be seen that an improved effect can be obtained as shown in FIG.

The present invention, as apparent from the above description the above described three kinds of compositions were tested both by the results of Test IEC896-2 obtained an effect that the capacity of about 20% increase, of the gel electrolyte 75 ~ 79.2wt% H ₂ O, 15 to 19.2 wt% SiO ₂ , 0.5 to 0.6 wt% Na ₂ SO ₄ , 5 to 6 wt% H ₃ PO ₄ and add 0.3 to 0.7 wt% sodium silicate or add 0.2 to Battery life can be prevented by adding 0.5wt% of sodium carboxymethyl cellulose or 0.1 ~ 0.3wt% of sodium silicate and 0.2 ~ 0.5wt% of sodium carboxymethyl cellulose to prevent drying of the gel due to water evaporation. There is an effect that can be extended.

Claims (4)

The basic composition of the gel electrolyte includes 75 to 79.3 wt% H ₂ O, 15 to 19.2 wt% SiO ₂ , 0.5 to 0.6 wt% Na ₂ SO ₄ , and 5 to 6 wt% H ₃ PO ₄ . A gel electrolyte of a long life sealed lead acid battery for photovoltaic / wind power generation. The method of claim 1, A gel electrolyte of a long life sealed lead-acid battery for photovoltaic / wind power generation, characterized by further adding 0.3 to 0.7 wt% of sodium silicate to the gel electrolyte. The method of claim 1, A gel electrolyte of a long life sealed lead-acid battery for photovoltaic / wind power generation, characterized in that 0.2 to 0.5 wt% of sodium carboxymethyl cellulose is further added to the gel electrolyte. The method of claim 1, A gel electrolyte of a long life sealed lead-acid battery for photovoltaic / wind power generation, further comprising 0.1 to 0.3 wt% sodium silicate and 0.2 to 0.5 wt% sodium carboxymethyl cellulose to the gel electrolyte.

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