CN1695260A - Positive electrode of lead-acid battery and lead-acid battery - Google Patents

Abstract

A positive plate for a lead storage battery, having a high ratio of utilization of the positive plate active material, prevented from lowering in life performance of itself, and excellent in discharge performance and life performance. The positive plate includes a positive plate grid made of a lead alloy containing 1.2 weight% or more of tin and a paste that is prepared by kneading a positive plate active material stock mainly containing a lead powder and red lead with dilute sulfuric acid and is applied to the grid. The positive active material stock contains 5 or more and 50 or less weight% of red lead. The porosity of the positive active material after formation is 58% or more. A lead storage battery is also disclosed.

Description

Positive electrode of lead-acid battery and lead-acid battery

technical field

The invention relates to the improvement of the utilization rate of the positive electrode active material, the improvement of the self-discharge characteristic of the lead-acid battery, and the avoidance of the deterioration of the cycle life performance of the lead-acid battery.

Background technique

Improvement in utilization of active materials in positive electrodes of lead-acid batteries, especially during high-rate discharge, is necessary to reduce battery weight and size, and many attempts have been made so far.

These attempts mainly attempt to increase the porosity of the cathode active material.

Increasing the porosity of the positive active material brings excellent results, but has the opposite effect on the life performance of the lead-acid battery. Therefore, the improvement of the porosity is limited, and so far, the upper limit of the porosity is about 60% from a practical point of view.

This is due to the fact that when the porosity increases, the binding force between the active materials becomes smaller, accompanied by a gradual decrease in the conductivity of the active materials, causing only the active materials near the grid to be discharged, thus causing the lead sulfate to be discharged in the grid. Accumulated around, the lead sulfate has extremely low electrical conductivity.

In particular, in recent years, tin containing about 1% by weight in the lead alloy of the grid has been widely used to improve the corrosion resistance of the positive electrode grid. However, when the composition ratio of tin increases, the bonding performance of the active material and the grid will deteriorate.

This is because a tin oxide film is formed on the surface of the grid during wet setting in the step of producing the positive electrode, impairing the bonding performance of the active material to the grid.

When the porosity of the positive electrode active material increases, the lifetime performance of the positive electrode deteriorates more than before, hindering the improvement of the performance of the lead-acid battery, so this is disadvantageous.

The present invention has been developed to solve the above-mentioned problems, and its problem (purpose) is to provide a positive electrode for a lead-acid storage battery, which contributes to improving the lead-acid battery by improving the utilization rate of the positive electrode active material and preventing the deterioration of the life performance of the positive electrode. Discharge characteristics and life characteristics of acid storage batteries.

Contents of the invention

In order to achieve the above objects, the present invention is described in the following items (1) to (8).

(1) A positive pole of a lead-acid storage battery, comprising:

Positive grids made of lead alloys with a tin content greater than or equal to 1.2% by weight, and

A lead paste filled therein obtained by kneading a positive electrode active material containing lead powder and red lead powder as main components with dilute sulfuric acid,

Wherein the content of the red lead component in the positive active raw material is 5% by weight to 50% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of this positive active raw material has a lead-acid battery that is greater than or equal to 58% after formation. Porosity of positive active material.

(2) The positive electrode of the lead-acid storage battery as described in item (1), wherein the content of the red lead composition in the positive electrode active material is greater than or equal to 5% by weight and less than 30% by weight, and with this positive electrode active The positive electrode of the lead-acid storage battery prepared from the lead paste made of raw materials has a porosity of the positive electrode active material greater than or equal to 58% after formation.

(3) The positive electrode of the lead-acid storage battery as described in item (1), wherein the content of the red lead composition in the positive electrode active material is 12% by weight to 42% by weight, and the content of the metallic lead composition in the lead powder is The content is 31% by weight to 40% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of this positive electrode active material has a positive electrode active material porosity greater than or equal to 58% after chemical formation.

(4) The positive electrode of the lead-acid storage battery as described in (3), wherein also contain metallic lead powder in described positive electrode active raw material, by the metallic lead composition in described lead powder and the metallic lead powder that thus adds Calculated, the content of the metal lead component in the positive electrode active material is greater than or equal to 19% by weight to less than 26% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of this positive electrode active material has A positive electrode active material porosity greater than or equal to 58%.

(5) The positive electrode of the lead-acid storage battery as described in item (1), wherein the content of the red lead component in the positive electrode active material is 10% by weight to 50% by weight, and the average particle diameter of the red lead powder is Less than or equal to 2.2 times the average particle size of the lead powder.

(6) The positive electrode of a lead-acid storage battery as described in item (1), wherein the lead powder is made of a lead alloy whose antimony content is 0.005% by weight to 0.1% by weight.

(7) The positive electrode of a lead-acid battery as described in any one of items (1) to (6), wherein the positive electrode grid is an expanded grid.

(8) A lead-acid storage battery comprising the positive electrode of the lead-acid storage battery as described in any one of items (1) to (7).

Description of drawings

Fig. 1 is a graph illustrating the change of initial capacity with the composition of red lead.

Fig. 2 is a graph illustrating the change in discharge capacity at the fifth cycle as a function of red lead composition.

Fig. 3 is a graph illustrating the variation of capacity ratio (B/A) with the composition of red lead.

Fig. 4 is a graph illustrating the relationship between the tin content and the amount of active material attached according to the change of the red lead composition.

Fig. 5 is a graph illustrating the discharge capacity at the fifth cycle as a function of metallic lead composition as a function of the red lead composition.

Fig. 6 is a graph illustrating the relationship between the initial capacity and the composition of metallic lead as the composition of red lead varies.

Fig. 7 is a graph illustrating the discharge capacity at the fifth cycle as a function of the metallic lead composition as a function of the red lead composition.

Fig. 8 is a graph illustrating the relationship between the capacity ratio and the metallic lead composition as the red lead composition is changed.

FIG. 9 is a graph illustrating test results for cycle life performance of a valve-regulated lead-acid battery.

Fig. 10 is a graph illustrating the capacity change of a valve-regulated lead-acid battery in a 60°C float test.

Figure 11 is a graph illustrating the particle size distribution of red lead.

Figure 12 is a graph illustrating the self-discharge rate as a function of red lead composition.

Figure 13 is a graph illustrating the cycle life ratio as a function of the weight percent antimony in the lead alloy for different red lead compositions.

Detailed ways

first embodiment

In the first embodiment, the positive electrode active material and red lead are mixed in a predetermined amount, even if the porosity of the positive electrode active material is greater than or equal to 58%, the life performance of the positive electrode can be improved.

The first embodiment will be further described below.

A grid with a height of 72 mm, a width of 45 mm and a thickness of 2.9 mm was prepared by expanding a lead alloy containing 0.05% by weight calcium and 1.5% by weight tin.

Then, each of these grids is filled with the positive electrode active material paste prepared according to the formula listed in Table 1 to a thickness of 3.0mm, to prepare samples No. 1 to No. 12 respectively, and to prepare a plurality of plates for each of these samples .

Subsequently, these samples were left in an atmosphere at a temperature of 50° C. and a humidity of 90 for 72 hours to be aged. Three plates were arbitrarily selected from each of these samples, and then a drop test of the active material was performed, which involved natural fall from a height of 90 cm repeated 20 times. The amount of active material attached to the surface of the grid was then measured.

Nine plates were independently selected from the above samples, and each was anodized (formed) with a total charge of 20Ah to form positive electrodes, including one 24-hour discharge in dilute sulfuric acid at a concentration of 28%.

The red lead powder used has a purity greater than or equal to 95%.

Subsequently, 6 plates were selected from these positive electrodes. The porosity of the positive active material of 3 of the 6 electrodes was then tested by the mercury penetration method, and the weight percentage of _PbO2 was determined for the other 3 electrodes after formation by the iodometric titration method .

The adhesion amount of the active material, the weight percentage of _PbO2 after formation, and the porosity thus determined are average values for each of three electrodes. The results are listed in Table 1.

For the preparation of common positive electrodes, the amount of the metallic lead component used in the lead powder in this embodiment is 25% to 30% by weight.

Dilute sulfuric acid is represented by the amount per 10kg of positive active material.

Table 1 Sample serial number lead paste After the active material drop test, the amount of active material attached to the unformed positive electrode (mg) Formed positive electrode Lead powder (weight%) Red lead composition (weight %) Specific gravity of dilute sulfuric acid - volume (l) %Porosity PbO ₂ (weight%) 1 100 0 1.14-1.5 450 54 91.3 2 100 0 1.16-1.7 290 56 91.5 3 100 0 1.16-1.9 252 58 91.9 4 100 0 1.16-2.2 223 62 92.5 5 100 0 1.16-2.4 191 64 93.6 6 97.5 2.5 1.16-2.2 268 62 93.0 7 95 5 1.16-2.2 506 62 93.5 8 88 12 1.16-2.2 621 62 94.5 9 82 18 1.16-2.2 653 63 94.8 10 76 twenty four 1.16-2.2 640 63 95.6 11 70 30 1.16-2.2 643 63 95.8 12 64 36 1.16-2.2 638 64 96.1

Subsequently, three more positive electrodes were added to three cells containing an excess of dilute sulfuric acid at a concentration of 40% and having lead plates as counter electrodes. These batteries are then discharged. The initial capacity A and discharge capacity B of these batteries were then measured at the 5th cycle.

Regarding the measurement conditions, the discharge current was a constant current of 0.7 A, and the discharge end voltage was -500 mV with respect to an independently prepared lead paste type electrode prepared by impregnating lead dioxide and lead in dilute sulfuric acid at a concentration of 40%. made of alloy.

The initial capacity A is the maximum capacity exhibited in 3 discharge cycles after formation. The discharge capacity at the 5th cycle is the discharge capacity displayed when the discharge at the 5th cycle is performed with the above-mentioned discharge displaying the initial capacity as the zero cycle. These results are shown in Table 2 together with the ratio of the discharge capacity B to the initial capacity A (capacity ratio B/A) at the 5th cycle.

Table 2 Sample serial number Initial capacity A(Ah) Discharge capacity B(Ah) of the 5th cycle Capacity ratio B/A 1 2.34 2.41 1.030 2 2.45 2.40 0.980 3 2.59 2.48 0.957 4 2.78 2.25 0.809 5 2.82 1.84 0.651 6 2.77 2.37 0.856 7 2.76 2.70 0.978 8 2.81 2.78 0.989 9 2.80 2.76 0.986 10 2.81 2.75 0.979 11 2.86 2.56 0.895 12 2.83 2.36 0.830

Subsequently, except that the positive electrode active material lead paste is prepared from positive electrode active raw materials containing 12% by weight of red lead according to the various formulations listed in Table 3, and then these positive electrode active material lead pastes are also filled in the above-mentioned grid. Samples numbered 1, 2 and 3 in Table 2 containing 100% by weight of lead powder were prepared in the same manner as samples numbered 1a, 2a and 3a, respectively.

In addition, according to the various formulations listed in Table 3, the positive electrode active material lead paste is prepared from the positive electrode active material containing 18% by weight of red lead, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. are samples of 1b, 2b and 3b.

In addition, according to the various formulations listed in Table 3, the positive electrode active material lead paste is prepared from the positive active material containing 24% by weight of red lead, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. Samples for 1c, 2c and 3c.

In addition, according to the various formulas listed in Table 3, the positive electrode active material lead paste is prepared from the positive active material containing 27% by weight of red lead, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. Samples for 1d, 2d and 3d.

In addition, according to the various formulations listed in Table 3, the positive electrode active material lead paste is prepared from the positive active material containing 30% by weight of the lead red component, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. Samples for 1e, 2e and 3e.

In addition, according to the various formulations listed in Table 3, the positive electrode active material lead paste is prepared from the positive electrode active material containing 36% by weight of red lead, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. are samples of 1f, 2f and 3f.

In addition, according to the various formulations listed in Table 3, the positive electrode active material lead paste is prepared from the positive active material containing 42% by weight of red lead, and then these positive electrode active material lead pastes are also filled in the above-mentioned grids, respectively. Available in 1g, 2g and 3g samples.

Each of these samples was then subjected to aging and anodization (formation) under the above conditions to form a positive electrode. The _PbO2 weight percent and porosity of each cathode were then determined after formation. The other 3 positive electrodes were then used to prepare the above batteries. The initial capacity, the discharge capacity at the 5th cycle, and the ratio of the discharge capacity B to the initial capacity A (B/A) at the 5th cycle of these batteries were each measured in the same manner. The results are listed in Table 3.

The change of the initial capacity with the change of red lead composition, the discharge capacity of the fifth cycle and the change of (B/A) ratio with the change of red lead composition are shown in Fig. 1, 2 and 3, respectively.

The ratio of (B/A) above gives an index of the lifetime performance of the positive electrode.

table 3 Sample serial number lead paste Formed positive electrode Initial capacity A(Ah) Discharge capacity B(Ah) of the 5th cycle Capacity ratio B/A Lead powder (weight%) Red lead composition (weight %) Specific gravity of dilute sulfuric acid - volume (l) %Porosity PbO ₂ (weight%) 1a 88% 12% 1.14-1.5 55 91.8 2.39 2.46 1.029 2a 88% 12% 1.16-1.7 57 91.9 2.49 2.55 1.024 3a 88% 12% 1.16-1.9 58 92.5 2.61 2.66 1.019 1b 82% 18% 1.14-1.5 55 91.9 2.40 2.50 1.042 2b 82% 18% 1.16-1.7 57 92.3 2.52 2.55 1.012 3b 82% 18% 1.16-1.9 59 92.9 2.62 2.72 1.038 1c 76% twenty four% 1.14-1.5 54 92.1 2.40 2.52 1.050 2c 76% twenty four% 1.16-1.7 57 92.8 2.53 2.60 1.028 3c 76% twenty four% 1.16-1.9 59 93.8 2.69 2.79 1.037 1d 73% 27% 1.14-1.5 54 92.1 2.41 2.52 1.046 2d 73% 27% 1.16-1.7 57 92.9 2.54 2.61 1.028 3d 73% 27% 1.16-1.9 59 93.8 2.73 2.83 1.037 1e 70% 30% 1.14-1.5 55 92.3 2.43 2.54 1.045 2e 70% 30% 1.16-1.7 56 92.9 2.54 2.62 1.031 3e 70% 30% 1.16-1.9 59 94.0 2.77 2.83 1.022 1f 64% 36% 1.14-1.5 55 92.8 2.42 2.51 1.037 2f 64% 36% 1.16-1.7 56 93.1 2.53 2.63 1.039 3f 64% 36% 1.16-1.9 59 94.2 2.82 2.81 0.996 1g 58% 42% 1.14-1.5 55 93.2 2.44 2.46 1.088 2g 58% 42% 1.16-1.7 57 93.6 2.55 2.52 0.988 3g 58% 42% 1.16-1.9 59 94.2 2.83 2.75 0.972

According to Figure 1 and Table 3, all samples numbered 1a to 1g having substantially the same porosity (54%-55%) as Sample 1 in Table 1 have substantially the same porosity as Sample 2 in Table 1 All samples numbered 2a to 2g (56-57%), all samples numbered 3a-3g with substantially the same porosity (58-59%) as sample 3 in Table 1, and samples in Table 2 Compared with the initial capacity of 1, it is shown that the initial capacity increases with the increase of red lead composition in the positive active material from 12 wt% to 42 wt%.

In particular, samples 3a to 3g (58%-59%) showed a significant increase in initial capacity as the red lead content in the cathode active material increased from 24 wt% to 36 wt%.

On the other hand, as can be seen in Figure 1 and Table 3, as long as the porosity is in the range of 54% to 57%, when the lead red component in the positive electrode active material increases, these samples show an increase in the initial capacity, but with the porosity Compared with samples with a rate of 58% to 59%, it not only shows a smaller initial capacity value, but also shows a smaller initial capacity growth rate.

Similarly, as long as the porosity ranges from 62% to 64%, these samples show an increase in initial capacity when the red lead content in the positive active material is increased, but compared with samples with a porosity of 58% to 59%, itself shows smaller initial capacity values.

Therefore, it can be expected that as long as the porosity is greater than or equal to 58%, the initial capacity increases when the red lead content in the positive active material increases.

This may be due to the increase in the weight percentage of _PbO after formation when the red lead content in the cathode active material increases, leading to an increase in the initial capacity.

Furthermore, according to FIG. 2 and Table 3, all samples numbered 1a to 1g having substantially the same porosity (54%-55%) as Sample 1 in Table 1 have substantially the same porosity as Sample 2 in Table 1. All samples numbered 2a to 2g with porosity (56-57%), all samples numbered 3a to 3g with substantially the same porosity (58-59%) as sample 3 in Table 1, and Table 2 Compared with the discharge capacity of the 5th cycle of the middle sample 1, it shows that the discharge capacity of the 5th cycle increases as the red lead content in the positive electrode active material increases to 30% by weight.

In particular, samples 3a to 3g (porosity = 58-59%) showed a significant increase in discharge capacity at the 5th cycle as the red lead content in the positive active material increased to 30 wt%. On the other hand, as can be seen from Figure 2 and Table 3, as long as the porosity is in the range of 54% to 57%, when the lead red component in the positive active material increases, these samples show a significant increase in the discharge capacity of the fifth cycle. However, compared with samples with a porosity of 58% to 59%, it not only shows a smaller value of the discharge capacity of the fifth cycle, but also shows a smaller growth rate of the discharge capacity of the fifth cycle.

In addition, as long as the porosity is in the range of 62%-64%, when the red lead content in the positive active material increases from 5 wt% to 30 wt%, the discharge capacity of the fifth cycle increases sharply. This tendency is particularly remarkable when the red lead content is 5% to 24% by weight.

Therefore, it can be expected that as long as the porosity is greater than or equal to 58%, the discharge capacity of the fifth cycle will increase when the red lead content in the positive electrode active material increases.

In addition, according to Fig. 3 and Table 3, all samples numbered 1a to 1g having substantially the same porosity (54%-55%) as Sample 1 in Table 1 have substantially the same porosity as Sample 2 in Table 1. All samples numbered 2a to 2g with porosity (56-57%), all samples numbered 3a to 3g with substantially the same porosity (58-59%) as sample 3 in Table 1, and Table 2 Compared with the capacity ratio (B/A) of sample 1, it shows that the capacity ratio (B/A) increases with the increase of lead red component in the positive electrode active material from 5% by weight to 27% by weight.

And it was also found that in samples 11, 12 in Table 1 and samples 1e to 3e, 1f to 3f, and 1g to 3g in Table 3, after the measurement of the discharge capacity of the 5th cycle, the positive electrode active material had accumulated in the battery.

This may be due to the reduction of the binding force of the positive active material due to the excessive red lead component, which destroys the conductive path between the positive active material particles as the charge-discharge cycle proceeds.

Therefore, when the positive electrode active material comprises lead lead powder greater than or equal to 5% by weight to less than 30% by weight, and the porosity of the positive electrode active material is greater than or equal to 58%, preferably 58% to 62%, the expected initial capacity and The discharge capacity of the 5th cycle can be improved for the positive electrode of the lead-acid battery.

It can be clearly seen from sample 4 and samples 6-11 in Table 1 that when the weight of red lead powder in the positive active material increases, the amount of active material attached increases.

This is because even when using a grid made of a lead alloy with a tin content of 1.5% by weight, the grid can form a tin oxide film on the surface of the grid, reducing the adhesion performance of the grid to the positive electrode active material, The presence of the red lead component can still improve the bonding performance of the grid and the positive active material.

In order to confirm this mechanism, positive electrode active material lead paste was prepared according to the same formulation as sample 4 and samples 6-11 in Table 1, and the lead paste was filled into cells with tin content of 1.2% by weight, 1.1% by weight and 1.0% by weight. grid. The same study was then performed on the amount of active material attached to these grids. The results are listed in Figure 4.

As can be seen from Figure 4, even if the weight of the red lead powder contained in the positive electrode active material increases, the grids with a tin content of 1.0% by weight and 1.1% by weight still show a smaller growth rate of active material adhesion, while When the positive electrode active material contained red lead powder greater than or equal to 5 wt%, the grids with tin contents of 1.2 wt% and 1.5 wt% showed a significant increase in the amount of active material attached.

This is believed to contribute to improved lifetime performance.

Therefore, when the positive electrode active material lead paste prepared from the positive active material containing 5% by weight to 30% by weight of red lead is filled to a grid with a tin content greater than or equal to 1.2% by weight, the estimated initial capacity and the fifth cycle can be obtained The discharge capacity can be improved by the positive electrode of the lead-acid battery.

second embodiment

The second embodiment relates to providing the positive electrode provided according to the above-mentioned first embodiment, in which the configuration of the red lead content of 30% or more is improved so that even if its porosity is 58% or more, the resulting positive electrode has insufficient life performance. It can also be no less than the first embodiment.

The premise of the lead powder of the first embodiment is that the amount of the metallic lead component is 25% by weight to 30% by weight. However, when the metallic lead component in the lead powder is more than 30% by weight, the effect in the first embodiment is likely to be weakened.

The purpose of the second embodiment is to effectively utilize lead powder even if its content of the above-mentioned metallic lead component is more than 30% by weight, because the production of lead powder with stable quality always requires a large investment in equipment.

In other words, the second embodiment has an object that even in this lead powder, a positive electrode not inferior to that of the first embodiment can be obtained by making the amount of the red lead component predetermined to be 30% by weight or more.

In the above-mentioned first embodiment, when the positive electrode active material is mixed with red lead powder, it is helpful to improve the life performance of the positive electrode. However, when the lead red component content is greater than or equal to 30% by weight, the binding force between the active materials is reduced, so the increase of the lead red component is limited, and the effect of fully exerting the positive electrode life-span performance by containing the lead red powder is impossible. In the second embodiment, this problem is solved by adjusting the content of metallic lead in the lead powder of the positive electrode active material.

The second embodiment will be further described below.

A grid with a height of 72 mm, a width of 45 mm and a thickness of 2.9 mm was prepared by expanding a lead alloy containing 0.05% by weight calcium and 1.5% by weight tin.

Each of these grids was filled with the positive electrode active material paste prepared according to the formula listed in Table 4 to a thickness of 3.0 mm to respectively prepare a plurality of plates for the samples listed in Table 4.

These samples were aged under the same conditions as in the first embodiment, and then anodized (formation) each with a total charge of 20Ah, which included a 24-hour discharge in dilute sulfuric acid at a concentration of 28%, to form a positive electrode .

The purity of the red lead powder used is 95%.

(Evaluation Test 1)

Then, for different positive electrodes prepared according to the formula listed in Table 4, the weight percentage and porosity of PbO ₂ after formation were tested under the same conditions as the first embodiment. The results are listed in Table 4.

Table 4 Sample serial number lead paste Formed positive electrode Lead powder (weight%) Red lead composition (weight %) Metallic lead in lead powder (weight%) Specific gravity of dilute sulfuric acid - volume (l) PbO ₂ (weight%) %Porosity A-1 100 0 26 1.16-2.2 92.5 62 A-2 88 12 26 1.16-2.2 94.5 62 A-3 82 18 26 1.16-2.2 94.8 63 A-4 76 twenty four 26 1.16-2.2 95.6 63 A-5 73 27 26 1.16-2.2 95.6 63 A-6 70 30 26 1.16-2.2 95.8 63 A-7 64 36 26 1.16-2.2 96.1 64 A-8 58 42 26 1.16-2.2 96.8 64 A-2′ 88 12 35 1.16-2.2 94.5 62 A-3′ 82 18 35 1.15-2.2 94.8 62 A-4′ 76 twenty four 35 1.16-2.2 95.6 63 A-5′ 73 27 35 1.16-2.2 95.6 63 A-6′ 70 30 35 1.16-2.2 95.8 63 A-7′ 64 36 35 1.16-2.2 96.1 63 A-8′ 58 42 35 1.16-2.2 96.2 62 A-2″ 88 12 40 1.16-2.2 93.5 62 A-3″ 82 18 40 1.16-2.2 94.0 62 A-4″ 76 twenty four 40 1.16-2.2 95.0 63 A-5″ 73 27 40 1.16-2.2 95.4 62 A-6″ 70 30 40 1.16-2.2 95.9 64 A-7″ 64 36 40 1-16-2.2 95.7 63 A-8″ 58 42 40 1.16-2.2 96.0 64 A-6 70 30 28 1.16-2.2 96.2 63 A-7 64 36 28 1.16-2.2 96.2 64 A-8 58 42 28 1.16-2.2 96.5 64 A-6′ 70 30 31 1.16-2.2 95.8 62 A-7′ 64 36 31 1.16-2.2 96.1 63 A-8′ 58 42 31 1.16-2.2 96.3 63

(Evaluation Test 2)

Under the same conditions as in the first embodiment, the measurements of the initial capacity A and the discharge capacity B at the 5th cycle were performed for each of the other three positive electrodes corresponding to the respective sample numbers different from the evaluation test 1 . The results are shown in Table 5 together with the results of the ratio of the discharge capacity to the initial capacity A at the 5th cycle (capacity ratio B/A).

Figure 5 shows the discharge capacity at cycle 5 as a function of red lead composition for each of the different metallic lead compositions.

table 5 Sample serial number Initial capacity A(Ah) Discharge capacity at the 5th cycle (Ah) Capacity ratio B/A A-1 2.78 2.25 0.809 A-2 2.81 2.78 0.989 A-3 2.80 2.76 0.986 A-4 2.81 2.75 0.979 A-5 2.82 2.69 0.954 A-6 2.86 2.56 0.896 A-7 2.83 2.35 0.830 A-8 2.80 2.20 0.786 A-2′ 2.79 2.77 0.993 A-3′ 2.79 2.76 0.989 A-4′ 2.79 2.76 0.989 A-5′ 2.82 2.72 0.965 A-6′ 2.85 2.69 0.944 A-7′ 2.81 2.61 0.929 A-8′ 2.83 2.59 0.915 A-2″ 2.77 2.77 1.000 A-3″ 2.77 2.75 0.993 A-4″ 2.80 2.77 0.989 A-5″ 2.84 2.79 0.982 A-6″ 2.84 2.74 0.965 A-7″ 2.80 2.69 0.957 A-8″ 2.84 2.60 0.915 A-6 2.83 2.59 0.916 A-7 2.85 2.51 0.882 A-8 2.84 2.44 0.860 A-6′ 2.86 2.68 0.936 A-7′ 2.86 2.62 0.914 A-8′ 2.85 2.57 0.902

In the above-mentioned evaluation test 2, the measured discharge capacity at the 5th cycle is shown in FIG. 5 by the change of the red lead composition in the lead powder for each metallic lead composition.

From Figure 5 and Table 4 and Table 5, it can be seen that compared with samples A-2 to A-5, samples A-1 and samples A-6 to A-8 have significantly lower discharge in the 5th cycle Capacity and capacity ratio (B/A), wherein, in sample A-1, use the lead powder that metallic lead composition is 26% by weight as the main component of positive electrode active material, and wherein not mixed with red lead powder, in sample A In -6 to A-8, lead powder with a metallic lead composition of 26% by weight is used as the main component of the positive electrode active material, and a lead lead composition greater than or equal to 30% by weight is mixed therein. In samples A-2 to A- In 5, lead powder with a metal lead content of 26% by weight is used as the main component of the positive electrode active material, and 12% to 27% by weight of red lead is mixed therein.

However, compared with samples A-2 to A-8, samples A-2' to A-8' (particularly samples A-6' to A-8') showed discharge capacity and Improvement of capacity ratio (B/A), wherein, in samples A-2' to A-8', lead powder having a metallic lead composition of 35% by weight was used as the main component of the positive electrode active material, and 12% by weight was mixed therein %～42% by weight of red lead powder.

This trend is also observed in samples A-2 "～A-8". In samples A-2 "～A-8", the lead powder with a metallic lead composition of 40% by weight is used as the main component of the positive electrode active material , and also mixed with red lead powder.

This may be attributed to the fact that there is an excessive amount of red lead in the positive electrode active materials of samples A-6～A-8, so there is a low binding force between the active material particles after chemical formation, while in samples A-6′～ A-8 ' and sample A-6 "～A-8 ", the metallic lead composition in the lead powder as positive electrode active raw material main component increases to 35% by weight or 40% by weight, so that red lead composition can be mixed with The metallic lead component undergoes a chemical reaction, which strengthens the bond between the particles.

In addition, the research on the optimal combination range of red lead and metallic lead in lead powder from Figure 5 shows that, compared with samples A-6～A-8, samples A-6～A-8 are the same as sample A -6′～A-8′ exhibited increased discharge capacity at the 5th cycle, thus increasing the capacity ratio (B/A), samples A-6～A-8 compared with sample A-6′ ～A-8′ respectively contain lead powders with metallic lead content of 28% and 31% by weight, and samples A-6～A-8 contain lead powder with metallic lead content of 26% by weight.

From this fact, it can be considered that there is an inflection point at which the capacity ratio (B/A) or lifetime performance exhibits a drastic change between the metallic lead composition of 28% by weight and 26% by weight.

Since the metallic lead component in the lead powder used in the production of common positive electrodes is 25% by weight to 30% by weight, the second embodiment does not give full play to improving the life performance of the positive electrode prepared from the lead powder as the positive electrode active material. However, it has played the role of overcoming the difficulty in preparing the following positive pole: the positive pole is made of lead powder mixed with red lead powder as a positive electrode active material, and the red lead content in the red lead powder is greater than or equal to 30% by weight %.

In other words, in the second embodiment, even when using lead powder containing a metallic lead component greater than or equal to 31% by weight, the calculated capacity ratio (B /A) greater than or equal to 0.9 positive electrode with good lifetime performance, thus contributing to improved lead powder yield.

In particular, when using lead powder with a metal lead content of 35% to 40% by weight, a positive electrode with better life performance, that is, a capacity ratio (B/A) greater than or equal to 0.91 can be obtained.

On the other hand, even when using the lead powder whose metallic lead composition is 25% by weight to 30% by weight, as long as the metallic lead composition in the lead powder is in the range of 28% by weight to 30% by weight, it can be as in sample A-6. A positive electrode with a high capacity ratio (B/A) was obtained as in .

The above evaluation test 1 and evaluation test 2 were made when the porosity of the positive electrode was about 62%. This is because, as can be seen from Figures 2 and 3, when the red lead composition exceeds 30% by weight, it is attempted to prevent the discharge capacity and capacity ratio (B/A) of the positive electrode having this porosity in the 5th cycle aspect of deterioration. Of course, without using lead powder with such a high content of metallic lead, the positive electrode with a porosity lower than 62% can also have good life performance.

In addition, when the metallic lead component in the lead powder is 31% to 40% by weight, even if the red lead component is less than or equal to 30%, preferably 12% to 30% by weight, the same effect can be produced.

It is undesirable that metallic lead composition is greater than or equal to 40% by weight in the lead powder, because the use of the ball mill type lead powder machine as the main modern lead powder production equipment will cause the particle size of the lead powder produced thereby to become large, which not only affects The performance of the positive electrode is affected, and the oxidation rate of metallic lead is increased, thereby causing an undesirable storage problem of lead powder.

The above-mentioned evaluation test 1 and evaluation test 2 are based on the metallic lead component in the lead powder. However, since the increase of the metallic lead content in the lead powder makes it difficult to control the conditions in the production process, it is necessary to reduce the metallic lead content in the lead powder.

Therefore, the positive electrode active material containing lead powder and red lead powder as main components may also contain metallic lead powder instead of increasing the metallic lead component in the lead powder.

In order to confirm this, the following evaluation tests were performed.

(Evaluation Test 3)

The positive electrode active material lead paste is prepared from the positive active material under the same conditions as in the second embodiment. The positive active material is prepared by mixing lead powder with a metallic lead content of 26% by weight, red lead powder and metallic lead powder according to the table. Prepared by mixing the recipes listed in 6. The positive electrode active raw material lead paste thus prepared was then filled into the same grid as used in the second embodiment to a thickness of 3.0 mm to prepare samples of the numbers listed in Table 6. Multiple plates were prepared for each of these samples.

These samples were aged under the same conditions as in the second embodiment, and then anodized (formation) each with a total charge of 20Ah, which included a 24-hour discharge in dilute sulfuric acid at a concentration of 28%, to form a positive electrode .

The purity of the red lead powder used is 95%.

Then, under the same conditions as in the first embodiment, the weight percent of PbO ₂ and the porosity after these anodized processes were measured respectively. The results are listed in Table 6.

Table 6 Sample serial number Raw materials for positive electrode active materials Formed positive electrode Lead powder (weight%) Red lead composition (weight %) Metal lead powder (weight%) Metal lead composition (%) PbO ₂ (weight%) %Porosity A-1 100.0 0.0 0.0 26.0 92.5 62 A-2 88.0 12.0 0.0 22.3 94.5 62 A-3 82.0 18.0 0.0 21.3 94.8 63 A-4 76.0 24.0 0.0 19.8 95.6 63 A-5 73.0 27.0 0.0 19.0 95.6 63 A-6 70.0 30.0 0.0 18.2 95.8 63 A-7 64.0 36.0 0.0 16.6 96.1 64 A-8 58.0 42.0 0.0 15.1 96.8 64 a-4′ 75.5 24.0 0.5 20.1 95.5 63 a-5′ 72.0 27.0 1.0 19.7 95.5 63 a-6′ 68.0 30.0 2.0 19.7 95.3 62 a-7′ 60.0 36.0 4,0 19.6 94.1 62 a-8' 52.0 42.0 6.0 19.5 93.5 62 a-2″ 85.0 12.0 3.0 25.1 94.5 62 a-3″ 77.0 18.0 5.0 25.0 95.2 62 a-4″ 68.0 24.0 8.0 25.7 95.0 62 a-5″ 64.5 27.0 8.5 25.3 93.6 61 a-6″ 60.5 30.0 9.5 25.2 92.8 62 a-7″ 52.5 36.0 11.5 25.2 89.8 61 a-8″ 44.5 42.0 13.5 25.1 88.2 61 a-2 78.0 12.0 10.0 30.5 85.3 61 a-3 70.0 18.0 12.0 30.2 83.0 60 a-4 62.0 24.0 14.0 30.1 80.5 59 a-9′ 47.5 45.0 7.5 19.6 93.8 62 a-10′ 43.2 48.0 8.8 20.0 93.7 62

(Evaluation Test 4)

Under the same conditions as in the second embodiment, the measurements of the initial capacity A and the discharge capacity B at the 5th cycle were performed for each of the other three positive electrodes corresponding to the respective numbers different from the evaluation test 3 . The results are shown in Table 7 together with the results of the ratio of the discharge capacity to the initial capacity A at the 5th cycle (capacity ratio B/A).

Figure 6 shows the change in the initial capacity with the change of the metallic lead composition of the metallic lead powder and with the change of the red lead composition, and Figure 7 shows the change in the discharge capacity at the 5th cycle under the same conditions as above , Figure 8 shows the change in capacity ratio (B/A) under the same conditions as above.

The reason for selecting the sample with a metallic lead content of 26% in the above evaluation test 3 and evaluation test 4 is that in the previous evaluation test 2, the discharge capacity of the fifth cycle showed There was a significant decrease.

Table 7 Sample serial number Initial capacity A(Ah) Discharge capacity B(Ah) of the 5th cycle Capacity ratio B/A A-1 2.78 2.25 0.809 A-2 2.81 2.78 0.989 A-3 2.80 2.76 0.986 A-4 2.81 2.75 0.979 A-5 2.82 2.69 0.954 A-6 2.86 2.56 0.895 A-7 2.83 2.35 0.830 A-8 2.80 2.20 0.786 a-4′ 2.80 2.70 0.964 a-5' 2.80 2.74 0.979 a-6′ 2.81 2.67 0.950 a-7′ 2.75 2.60 0.945 a-8' 2.71 2.58 0.952 a-2″ 2.71 2.68 0.989 a-3″ 2.76 2.70 0.978 a-4″ 2.76 2.73 0.989 a-5″ 2.72 2.64 0.971 a-6″ 2.65 2.60 0.981 a-7″ 2.49 2.45 0.984 a-8″ 2.41 2.46 1.021 a-2 2.39 - - a-3 2.11 - - a-4 1.99 - - a-9′ 2.61 2.50 0.958 a-10′ 2.52 2.25 0.893

As can be seen in Fig. 6～Fig. 8 and Table 6 and Table 7, when the lead powder of 26% by weight as the metallic lead composition content of main component is mixed with metallic lead powder, and then when mixed with red lead powder, positive electrode activity The percentage of metallic lead in the raw material decreases with the increase of red lead, but its content can be increased when metallic lead powder is included to make up for the loss.

As a result, an improvement in the discharge capacity at the 5th cycle was seen.

For example, the sample A-6 (same as sample A-6 in Table 5) that contains lead lead component content as 30.0% by weight contains metallic lead component and is 18.2% by weight, when mixed with metallic lead powder to make the content of metallic lead powder reach 2.0% by weight simultaneously. % by weight, sample a-6' contained 19.7% by weight of metallic lead components.

In addition, when mixed with metallic lead powder to make the content of metallic lead powder reach 9.5% by weight, the sample a-6 "contains 25.2% by weight of metallic lead composition. In any case, it is possible to increase the content of metallic lead composition in the positive active material. % by weight.

As a result, the discharge capacity at the 5th cycle was improved compared to the case where no metallic lead powder was contained.

However, sample A-7 (same as sample A-7 in Table 5) with a red lead content of 36.0% by weight and sample A-8 with a red lead content of 42.0% by weight (same as sample A-7 in Table 5) 8) contain 16.6% by weight and 15.1% by weight of metallic lead components respectively, and when mixed with metallic lead powder to make the content of metallic lead powder reach 4.0% by weight and 6.0% by weight respectively, sample a-7' and sample a- 8' contained 19.6% by weight and 19.5% by weight of metallic lead components, respectively.

In addition, when mixed with metallic lead powder so that the content of metallic lead powder was 11.5% by weight and 13.5% by weight, sample a-7″ and sample a-8″ contained 25.2% by weight and 25.1% by weight of metallic lead components, respectively.

As a result, it is found that the weight percent of the metallic lead composition in the positive electrode active material can be improved, and compared with the situation not containing metallic lead powder, the discharge capacity of the 5th cycle can also be improved, but sample a-7 " and sample a-8 ″ and sample a-2～sample a-4 decreased initial capacity.

This may be due to the fact that samples a-7" and a-8" showed a decrease in the weight percent of PbO ₂ after formation compared to samples A-7 and A-8.

This may be due to the fact that when the content of the metallic lead powder exceeds 10% by weight, the metallic lead powder reacts with the red lead powder, which, in addition to enhancing the binding force between the particles of the positive electrode active material, also produces an effect that reduces the positive polarization formation efficiency. Effect.

This will be apparent from the fact that the initial capacities of samples a-2'' to sample a-4'' decreased, these samples containing metallic lead powder such that the metallic lead composition exceeded 30.0% by weight.

In addition, it is apparent from Fig. 6 to Fig. 8 and Table 6 and Table 7 that sample a-9' and sample a-10' contain lead having a metal lead content of 26% by weight as a main component mixed with metal lead powder. powder, and then mixed with red lead powder so that the contents of red lead components were 45.0% by weight and 48% by weight, and the discharge capacity of the 5th cycle of the sample showed a significant decrease.

It can be clearly seen from the above introduction that in the case of using lead powder with a metallic lead content of 26% by weight as the positive electrode active material, when the red lead composition is predetermined to be 30% by weight to 42% by weight, and contains the metallic lead composition of When the metal lead powder is 19 wt %-26 wt %, the initial capacity and the discharge capacity of the fifth cycle can be improved.

In particular, when the metallic lead powder is contained at 10% by weight or less, as in samples a-4' to a-8' and a-2" to a-6", the above effects can be remarkably produced.

Even when the metallic lead component is predetermined to be greater than or equal to 19% by weight to less than 26% by weight in the lead powder by containing the metallic lead powder, the lead lead composition can be predetermined to be less than or equal to 30% by weight, preferably 12% by weight. % by weight to 30% by weight to produce the same effects as shown in Figures 6 to 8 above.

Regarding the technical effective scope of the present invention, its spirit is, on the basis of above-mentioned first and second embodiment and evaluation experiment 1～evaluation experiment 4, with the configuration of lead powder and red lead powder as the main component of positive electrode active material, Preferred:

1. In the positive pole of a lead-acid battery, the positive pole contains a positive grid filled with lead paste obtained by kneading the positive active material mainly containing lead powder and red lead powder with dilute sulfuric acid, the above The red lead component in the positive electrode active material is greater than or equal to 5% by weight to less than 30% by weight, preferably 5% by weight to 24% by weight;

2. The content of red lead in the positive active raw material is 12% to 42% by weight, and the lead metal in the lead powder is 31% to 40% by weight;

3. The above-mentioned positive electrode active raw material also contains metallic lead powder, the red lead composition in the raw material is 12% to 42% by weight, and the metallic lead composition in the raw material is greater than or equal to 19% by weight to less than 26% by weight; and

4. In addition, the content of metallic lead powder in the raw material is less than 10% by weight.

third embodiment

The third embodiment relates to a configuration in which the self-discharge characteristics of the positive electrode of the lead-acid storage battery according to the first and second embodiments can be improved by limiting the average particle size of the red lead powder even if the lead powder contains a large amount of red lead powder , without compromising the cycle life performance of lead-acid batteries.

By containing red lead powder in lead powder produced by using a Shimadzu type ball mill or a Burton type lead powder machine, the self-discharge characteristics of the lead-acid storage battery can be improved. However, when a large amount of red lead powder is contained, red lead powder reacts with sulfuric acid in the electrolyte to generate lead sulfate, which then grows to be larger than the pores in the positive electrode, resulting in the destruction of the bonding structure of the active material, thus reducing the This is disadvantageous for the lifetime performance of the positive electrode.

In the third embodiment, the particle size distribution of the red lead powder is predetermined to be an appropriate range with respect to the particle size distribution of the lead powder, so that even when the red lead powder to be contained in the lead powder (the main component of the positive electrode active material) When reacting with sulfuric acid to generate lead sulfate, the particle size of lead sulfate will not increase too much relative to the average particle size of lead powder.

In this configuration, the bonding structure of the active material can be prevented from being damaged, so that the effect of improving self-discharge characteristics by containing red lead powder can be exerted without reducing the life performance of the lead-acid battery.

The third embodiment will be further described below.

The lead powder used in this embodiment is produced by a Shimadzu type ball mill, and its average particle size and content of metallic lead components are 2.3 μm and 25% to 30% by weight, respectively.

The average particle size of red lead powder is about 2.2 μm.

The mixture of lead powder and red lead powder is kneaded with dilute sulfuric acid to prepare positive electrode active material lead paste.

The positive electrode active material lead paste thus prepared was filled into the expanded grid and the cast grid, and then aged under the same conditions as in the first embodiment.

In this embodiment, lead powder and red lead powder are dispersed in a 3:1 mixed solvent of cyclohexanol and methanol, and the sedimentation velocity is measured simultaneously to calculate the average particle size.

Table 8 lists the densities of the pastes prepared from the positive electrode active materials with red lead content of 0% to 50% by weight during kneading and after aging.

The reason for limiting the content of the red lead component to 50% by weight is that even when the content of the red lead component exceeds 50% by weight, there is no influence on the cycle life performance described below (see Table 10).

The density of the positive electrode active lead paste prepared by mixing the mixture of lead powder and red lead powder whose content of red lead content varies below 50% by weight with dilute sulfuric acid is almost the same as that without red lead during kneading, after aging and drying. The prepared positive active lead pastes have the same density.

From this fact, it can be considered that in the step of kneading positive active lead paste, dilute sulfuric acid and red lead powder, etc., the reactivity of lead powder and red lead powder with dilute sulfuric acid is almost the same as that of lead powder.

The specific gravity of the dilute sulfuric acid used here is 1.16, and the mixing ratio is 2.0 liters per 10 kg of positive electrode active materials mainly containing lead powder and red lead powder.

Table 8 Red lead content (weight%) Paste density during kneading (g/cm ³ ) Paste density after aging and drying (g/cm ³ ) Remark 0 4.02 3.44 comparative example 10 4.03 3.43 Example 1 20 4.04 3.45 Example 2 30 4.02 3.47 Example 3 40 4.03 3.45 Example 4 50 4.02 3.45 Example 5

Under the pressure of 40kg/ ^dm2 generated by stacking, the formed positive electrode, negative electrode and fine glass bottom plate holder were mounted on a valve-regulated lead-acid battery with a capacity equivalent to 7AH (20 hour rate), and the positive electrode was passed through The matured and dried positive electrodes (including cast grids) listed in Table 8 were prepared by so-called channel formation with dilute sulfuric acid having a specific gravity of 1.10, and the negative electrodes were prepared by chemical formation and drying by almost the same process.

The electrolyte that has been injected into the VRLA battery is dilute sulfuric acid with a specific gravity of 1.300.

The VRLA batteries prepared in this way are Comparative Example and Examples 1-5. Each of these valve-regulated lead-acid batteries was charged about 150% with a current of 10 hours, placed at 40°C for 30 days, and then tested for self-discharge characteristics.

Similarly, under a pressure of 40 kg/ ^dm2 generated by stacking, the cured and dried positive electrodes (including expanded grids) listed in Table 8, the negative electrodes cured and dried by almost the same process Assembly with a fine glass bottom plate holder, followed by so-called box formation, to prepare a valve-regulated lead-acid battery with a capacity equivalent to 7AH (20 hour rate).

As the electrolytic solution, dilute sulfuric acid with a specific gravity of 1.225 to 1.245 can be used so that the specific gravity reaches 1.300 at the end of the box-type chemical conversion.

The valve-regulated lead-acid battery prepared in this way was also used as a comparative example and Examples 1 to 5 respectively corresponding to lead red components, and was placed at 40° C. for 30 days, and then the self-discharge characteristics were tested in the same way.

In order to measure the self-discharge characteristic, the difference between the discharge of the first cycle after standing for 30 days and the average value of three discharge cycles after charging with a current of 10 hours rate of 8.4AH was divided by 30. Multiplying the quotient by 100 gives the self-discharge rate. Table 9 shows the results.

Table 9 Positive type Self-discharge rate (%/day) Batteries prepared by trough formation Batteries prepared by box formation comparative example 2.5 2.1 Example 1 2.0 1.6 Example 2 1.4 1.0 Example 3 1.2 0.9 Example 4 1.2 0.8 Example 5 1.1 0.8

It can be seen from Table 9 that the self-discharge rates of the samples prepared by both tank and box formations showed a decrease with the increase of red lead composition.

When the red lead composition is greater than or equal to 30% by weight, the decrease in the self-discharge rate becomes slightly slower.

In addition, the absolute value of the self-discharge rate of the valve-regulated lead-acid battery containing the positive electrode prepared by box formation is smaller than that of the valve-regulated lead-acid battery containing the positive electrode prepared by tank formation.

Subsequently, the cycle life performance test was performed on the valve-regulated lead-acid battery that had undergone tank formation above under the following conditions according to JISC8702, and the test temperature was 25°C±2°C.

Discharge 0.25CA 2 hours

Charging 0.1CA 6 hours

Confirmation of the capacity was carried out by discharging from a fully charged state to a cut-off voltage of 1.7 V/cell every 25 cycles with a discharge current corresponding to 0.25 CA. A cycle at which the battery exhibited a capacity drop of 50% or less of the initial capacity was judged as the cycle life.

These results are shown in Table 9.

As can be seen in Table 9, the battery of Example 5 (containing 50% by weight of red lead component) also had the same cycle life performance as that of the comparative example.

The capacity test results of the floating charging comparative example and the embodiments 1 to 5 in the floating charging application are shown in FIG. 10 . The battery of Example 3 (containing 30% by weight of red lead component) had the smallest capacity drop.

For the float test, the capacity is confirmed every month by performing an accelerated float test at 60°C and 2.275V/battery.

Confirmation of capacity was carried out under the same conditions as the above-mentioned cycle life performance test. The point at which the capacity drops to 60% or less of the initial capacity is judged as the float life.

The peak average particle size of the red lead powder listed in Table 8 is about 2.2 μm (about 1.0 times the average particle size of the lead powder; hereinafter referred to as "red lead A"). Lead-acid batteries have an average particle size peak of about 5.0 μm (about 2.2 times the average particle size of lead powder; hereinafter referred to as "lead red B"), about 10.5 μm (about 4.6 times the average particle size of lead powder ; hereinafter referred to as "lead red C") and about 14.9 μm (about 6.5 times the average particle size of lead powder; hereinafter referred to as "lead red D") red lead powder preparation.

Table 10 shows the results of the self-discharge test, the cycle performance test and the accelerated float charge test at 60° C. performed on these batteries under the same conditions as those of the third embodiment.

The particle size distribution of red lead A to red lead D is shown in Fig. 11 .

The average particle diameter of the lead powder was 2.3 μm.

Table 10 Red lead composition Particle size ratio 1.0 (lead red A) 2.2 (Lead red B) 4.6 (Lead red C) 6.5 (lead red D) 40% self-discharge rate [%/day] 0% by weight 2.5 - - - 10% by weight 2.0 2.5 2.7 2.9 20% by weight 1.4 1.6 2.6 3.0 30% by weight 1.2 1.3 2.6 3.2 40% by weight 1.2 1.3 2.9 3.2 50% by weight 1.1 1.2 3.0 3.2 cycle life 0% by weight 300 cycles - - - 10% by weight 310 cycles 310 cycles 290 cycles 280 cycles 20% by weight 320 cycles 320 cycles 280 cycles 270 cycles 30% by weight 340 cycles 330 cycles 270 cycles 260 cycles 40% by weight 320 cycles 310 cycles 270 cycles 250 cycles 50% by weight 310 cycles 300 cycles 270 cycles 240 cycles 60℃float charge life 0% by weight 12.5 months - - - 10% by weight 13.2 months 13.2 months 12.5 months 11.0 months 20% by weight 14.2 months 14.2 months 11.8 months 10.2 months 30% by weight 15.3 months 15.0 months 10.7 months 9.8 months 40% by weight 14.8 months 14.4 months 10.2 months 9.7 months 50% by weight 14.4 months 14.4 months 9.9 months 9.3 months

It can be seen from Table 10 that when the weight percentage of red lead is the same, the cycle life of lead-acid batteries prepared from lead red C and lead red D is shorter than that of lead-acid batteries prepared from lead red A and lead red B.

This may be because when the average particle size of the red lead powder exceeds 2.2 times the average particle size of the lead powder, the particle size of the lead sulfate crystals generated by decomposing the red lead powder with dilute sulfuric acid increases, destroying the bonding structure of the positive active material .

This may also be due to the reduced lead sulfate yield, increasing the amount of lead dan that reacted with sulfuric acid during the self-discharge test. As a result, the float current increased during the 60°C accelerated float test, accelerating the corrosion rate of the positive grid, thus reducing the float life.

It can be seen in Figure 12 that when the red lead composition increases, as long as the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder, the discharge rate at 40°C will decrease. , as long as the average particle size of red lead powder is greater than or equal to 2.2 times the average particle size of lead powder, the discharge rate at 40°C will increase.

From this fact it is evident that the effect produced by the inclusion of red lead powder contributes to the reduction of the self-discharge rate, whether the cell is subjected to channel formation or box formation.

Judging from the above description, for the self-discharge rate at 40°C, it is preferable that the red lead composition is 20% to 50% by weight and the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder. Preferably, the red lead component is 30% to 50% by weight and the average particle size of the red lead powder is 1.0 times the average particle size of the lead powder.

In addition, regarding the cycle life, it is preferable that the red lead content is 10% to 50% by weight and the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder.

Preferably, the red lead component is 20% to 40% by weight and the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder.

In addition, for the cycle life at 60°C, it is preferred that the red lead content is 10% to 50% by weight and the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder.

Preferably, the red lead component is 20% to 40% by weight and the average particle size of the red lead powder is less than or equal to 2.2 times the average particle size of the lead powder.

Furthermore, the third embodiment has been described with reference to a lead-acid battery comprising a fine glass base holder. Since the lead-acid storage battery is under pressure, even if the red lead component is 50% by weight, the effect of containing red lead powder can be exerted without causing the active material to fall off.

Fourth Embodiment

The fourth embodiment resides in the positive electrode of the lead-acid storage battery according to the above-mentioned first to third embodiments, in which lead powder produced from a lead alloy containing a predetermined amount of antimony (Sb) is used, whereby even when the red lead content increases, Early deterioration of the cycle life performance of the positive electrode can be suppressed while suppressing a decrease in discharge capacity due to softening of the positive electrode active material, thereby providing a lead-acid battery having excellent cycle life performance.

When the positive electrode is made of red lead powder and lead powder as the active raw material of the positive electrode, the bonding performance of the active material and the grid is enhanced. However, when the lead powder is made of an antimony-containing lead alloy, the synergistic effect produced by the combination of the lead powder and red lead powder enhances the binding properties of the active material particles.

In particular, when the red lead component is 5% to 50% by weight based on the active material of the positive electrode, the combination performance of the active material of the positive electrode and the grid is enhanced. In addition, when lead powder made of a lead alloy having an antimony (Sb) content of 0.005 wt% to 0.1 wt% based on the weight of lead is used, softening of the positive electrode active material can be suppressed, significantly improving the lifetime performance of the positive electrode.

The fourth embodiment will be further described below.

Pb-Sb alloys with different antimony (Sb) contents were processed with a ball mill to produce lead powder.

These lead powders are made of 7 lead alloys containing 25% to 30% by weight of metallic lead and 0.001% by weight, 0.005% by weight, 0.01% by weight, 0.05% by weight, 0.1% by weight based on the weight of lead. % by weight, 0.5% by weight and 1% by weight of the antimony (Sb) component.

In addition, lead powder (antimony content: 0% by weight) made of pure lead was also used.

Then the above-mentioned various lead powders are mixed so that the red lead content is respectively 3% by weight, 5% by weight, 10% by weight, 20% by weight, 30% by weight, 45% by weight, 50% by weight and 75% by weight based on the positive electrode active material, In order to prepare the positive electrode active material lead paste, the density of the lead paste after kneading is 3.85 g/cm ³ .

Subsequently, each of the above-mentioned lead pastes was filled into an expanded grid containing a Pb alloy having a Ca content of 0.08% by weight and a Sn content of 1.5% by weight, and then aged and dried under the same conditions as in the first embodiment to obtain An unformed positive electrode having a thickness of 1.6 mm was prepared.

The unformed positive electrode showed a paste density of 4.02 g/cm ³ and a porosity of 59%.

These positive active materials for filling into grids were prepared such that the molar amount of lead was the same in different formulations.

In addition, as mentioned above, when the amount of tin added increases, the positive electrode grid shows improved corrosion resistance, but when the amount of tin added is greater than or equal to 1.2 wt%, the combination of the unformed active material and the grid is weakened.

Therefore, considering conventional experience, the scope of application of this embodiment is lead alloys with a tin content of 1.5% by weight, which mainly cause problems of bonding of active materials to grids prepared by doping tin.

The rated capacity is 36Ah (5 hours rate) and the lead-acid storage battery of voltage is 2V, by 6 positive poles, 7 negative poles and polyethylene separators with a thickness of 1.3mm prepared by the same method as the third embodiment are used with the first The three embodiments are prepared by the same method.

In addition, a similar lead-acid battery is made from a positive electrode containing a positive active material lead paste made of lead powder produced from a lead alloy containing antimony (Sb) without lead lead powder and from pure lead production.

The cycle life performance of various lead-acid batteries was tested to compare the capacity reduction due to flaking of the active material on the grid with the capacity reduction due to softening of the active material, and the results are shown in Figure 13.

The cycle life performance test is carried out under the following conditions: the ambient temperature is 40°C, the battery is discharged with a current of 20A for 1 hour, and charged with a constant current of 5A for 5 hours (125% of the discharge capacity).

In order to confirm the capacity, discharge in the 25th cycle was performed at an ambient temperature of 40° C. at a current of 20 A. After the voltage reaches 1.7V, measure the discharge capacity.

During the cycle life test or confirmation of capacity, when it is confirmed that the discharge capacity has dropped to less than or equal to 50% of the rated capacity, and the subsequent discharge shows that the capacity no longer increases, the life of the battery is determined.

Prepare lead powder by the pure lead that does not contain lead danmo, prepare positive electrode active material lead paste by this lead powder, be 100% with the cycle number of the lead-acid accumulator that comprises this positive electrode active material lead paste, the cycle life ratio in Fig. 13 Indicates a value relative to this cycle number.

As can be seen in Figure 13, the life of a lead-acid battery comprising a positive electrode made of positive active material lead paste (prepared from lead powder prepared from pure lead without red lead powder) terminates at the initial stage of the cycle life performance test .

When the lead-acid battery was disassembled for inspection, it was found that the peeling of the positive active material from the grid resulted in a decrease in the capacity of the positive electrode, thus limiting the capacity of the battery.

On the other hand, a lead-acid storage battery comprising a positive electrode made of a positive active material paste, wherein the positive active material paste is made of a positive active raw material with a content of red lead powder greater than or equal to 5% by weight, regardless of whether the lead powder is Produced from pure lead or from antimony-containing lead alloys, the life is not terminated at the initial stage of the cycle life performance test. Therefore, the improvement of cycle life performance by the inclusion of red lead powder was confirmed.

Therefore, it was confirmed that batteries containing lead lead powder prevented their capacity from decreasing and their life from being terminated at the initial stage of the cycle life performance test, regardless of whether the lead powder was produced from pure lead or lead alloy.

It is considered that lead-acid storage batteries prepared from lead powder produced from pure lead and having a red lead content greater than 30% by weight have the effect of preventing initial capacity reduction in the cycle life performance test. However, it has now been found that lead-acid batteries prepared from lead powder produced from one antimony (Sb) lead alloy do not have the recognized effect of lead-acid batteries prepared from lead powder produced from another antimony (Sb) lead alloy .

This is due to the fact that the fourth embodiment is an unpacked lead-acid battery, which undergoes a process of softening and exfoliation of the positive active material as charge-discharge cycles proceed. However, it is considered from the description below that this is because of the synergistic effect of the combination of lead powder produced by an antimony (Sb)-containing lead alloy and red lead powder.

In addition, the lead-acid battery containing 3 wt% red lead content showed a greater capacity reduction in the initial stage of the cycle life performance test compared to the lead-acid battery with higher red lead content. This trend is similar to that of lead-acid batteries prepared from lead powder produced from pure lead.

This may be because the weight percentage of red lead composition is very small, which limits the effect of red lead composition.

The following effects have been demonstrated: Compared with lead-acid batteries prepared from lead powders produced from pure lead, lead-acid batteries prepared from lead powders containing antimony (Sb) lead alloys in cycle life performance tests, and in In the range where the composition exceeds 30% by weight, a smaller decrease in capacity is shown. However, in the range where the red lead content exceeds 50% by weight, little or no life-enhancing effect is obtained by using lead powder produced from an antimony-containing lead alloy.

It can be judged from the above results that the percentage by weight of red lead is preferably 5% by weight to 50% by weight based on the active material of the positive electrode.

The conditions under which the antimony contained in the lead powder sufficiently functions will be described below.

As shown in Figure 13, when the content of the red lead component is 5% to 50% by weight, compared with the lead-acid battery prepared from the lead powder produced from pure lead, it can be found that the antimony content based on lead is 0.005% by weight Lead-acid batteries prepared from lead powder produced from ~0.1% by weight lead alloy have improved cycle life performance.

When inspected after end-of-life, these lead-acid batteries were confirmed to have a capacity limited by the positive electrode.

However, it has been found that when lead powder produced using a lead alloy having an antimony content greater than or equal to 0.5% by weight of lead, cycle life performance deteriorates contrary to the above.

As a result of disassembly inspection after the end of life, it was found that the above phenomenon is caused by the mechanism that the negative electrode deteriorates faster than the positive electrode, which limits the discharge capacity.

Therefore, it is obvious that when the positive electrode active material contains 5% to 50% by weight of red lead powder and is produced by a lead alloy in which the content of antimony (Sb) based on the lead weight is 0.005% to 0.1% by weight, it can fully exert its resistance to The role of cycle life performance.

In all the above-described embodiments, grids produced by expanded mesh are used. Since this grid is produced by rolling a lead alloy into a sheet, scoring grooves in the sheet, and drawing the grooves of the sheet, the resulting grid has a smoother surface than a grid produced by casting.

Therefore, the bonding performance of the positive electrode active material to the grid is lower than that of the cast grid. Therefore, increasing the porosity of the positive active material leads to further deterioration of the bonding performance of the positive active material and the grid. However, when the positive electrode active material contains red lead powder, the deterioration of bonding performance can be overcome, making it possible to obtain a lead-acid battery with excellent cycle life characteristics through an expanded grid with excellent productivity.

Therefore, the invention can also be applied to batteries comprising cast grids.

Industrial Applicability

As described above, according to the present invention, as long as the positive electrode grid is made of lead alloy with a tin content greater than or equal to 1.2% by weight, the aging step in the production process of the positive electrode produces a tin oxide film that weakens the contact between the active material and the positive electrode grid. The bonding performance of the grid, but the bonding performance of the positive active grid and the active material will not be weakened by including a predetermined amount of red lead powder in the positive active material.

In addition, in the case where the positive electrode active material contains red lead powder, the binding force between the active materials deteriorates. However, by pre-determining the metallic lead composition in the lead powder in the positive electrode active raw material or mixing the raw material with the metallic lead powder, the oxidation-reduction reaction of red lead and metallic lead can be accelerated in the aging step or the subsequent formation step, so that at the end of the formation step It becomes possible to suppress the deterioration of the bonding force at the time, thereby obtaining a positive electrode that can be used for a long period of time.

Therefore, the present invention makes a very large industrial contribution.

Claims (8)

1. A positive pole of a lead-acid storage battery, the positive pole comprising: Positive grids made of lead alloys with a tin content greater than or equal to 1.2% by weight, and The lead paste filled therein, the lead paste is obtained by kneading the positive electrode active material containing lead powder and red lead powder as main components with dilute sulfuric acid, wherein the content of lead lead component in the positive electrode active material is 5 wt. % to 50% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of this positive active material has a positive active material porosity greater than or equal to 58% after formation. 2. The positive pole of lead-acid storage battery as claimed in claim 1, wherein the content of the red lead component in the positive pole active material is greater than or equal to 5% by weight and less than 30% by weight, and is made of thus positive pole active material The positive electrode of the lead-acid storage battery prepared by the lead paste has a positive electrode active material porosity greater than or equal to 58% after formation. 3. The positive pole of lead-acid storage battery as claimed in claim 1, wherein the content of the red lead composition in the positive active material is 12% by weight to 42% by weight, and the content of the metallic lead composition in the lead powder is 31% by weight. % by weight to 40% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of this positive electrode active material has a porosity of the positive electrode active material greater than or equal to 58% after formation. 4. the positive pole of lead-acid storage battery as claimed in claim 3, wherein also contain metallic lead powder in described positive electrode active raw material, calculate by the metallic lead composition in the metallic lead powder of described lead powder and thus adding, so The content of the metallic lead component in the positive active raw material is greater than or equal to 19% by weight or less than 26% by weight, and the positive electrode of the lead-acid storage battery prepared from the lead paste made of the positive active raw material has a mass greater than or equal to 58% positive active material porosity. 5. the positive pole of lead-acid storage battery as claimed in claim 1, wherein the content of the red lead composition in the positive active material is 10% by weight～50% by weight, and the average particle diameter of described red lead powder is less than or equal to 2.2 times the average particle size of the lead powder. 6. The positive electrode of a lead-acid storage battery as claimed in claim 1, wherein the lead powder is made of a lead alloy whose antimony content is 0.005% by weight to 0.1% by weight. 7. The positive pole of a lead-acid battery as claimed in any one of claims 1 to 6, wherein the positive grid is an expanded grid. A lead-acid storage battery comprising the positive electrode of the lead-acid storage battery according to any one of claims 1 to 7.

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