JP2009206016A - Anode lattice base board for lead storage battery and control valve type lead storage battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve type lead storage battery which prevents a fallout of an active substance in a leg upper portion of an anode filling plate, and also prevents an inner short circuit in a leg portion of an electrode plate group provided with the anode. <P>SOLUTION: In the anode lattice base board 1 for a lead storage battery which has a main composition of lead or lead alloy and has a leg portion, the width of the leg portion 14 is made to be wider than that of a cathode electrode plate. The board has at least one of following structures: (1) at least one reinforcing lattice 16 is added in a grid of the lattice positioned in an upper portion of the leg portion; (2) at lease one of intermediate lattices 12 positioned in an upper portion of the leg portion is made thick; and (3) a frame lattice 11 composing a lower portion of the grid positioned in an upper portion of the leg portion is made thick. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a negative electrode grid substrate for a lead storage battery and a control valve storage battery using the same.

   Lead-acid batteries have a long history like nickel-cadmium batteries, and still occupy the mainstream of storage batteries because of their high reliability from stable performance as well as their low cost. Widely used as an emergency power source for power supplies and computers. In particular, recently, the use of a control valve type lead-acid battery having an increased capacity of the negative electrode in the battery and improved hermeticity due to advantages such as ease of maintenance and very little exhaust gas has been increasing.

In these lead-acid batteries, first, positive and negative electrode active materials are filled into a lattice substrate such as a lead alloy, and after aging and drying processes, positive and negative electrode plates are formed, and then in a chemical conversion tank containing dilute sulfuric acid. A positive electrode plate and a negative electrode plate that have been subjected to chemical conversion treatment by energization are completed. Usually, a plurality of sheets are put into a storage battery tank as an electrode plate group alternately combined via separators, an upper lid is attached, and a dilute sulfuric acid electrolyte is added from a liquid injection port immediately before use to obtain a product storage battery. In the above-mentioned chemical conversion method (immediate chemical conversion), there is a problem that the performance variation of the electrode plate increases due to the difference in conditions depending on the position in the chemical tank from the chemical conversion tank size or the instability of the specific gravity of diluted sulfuric acid due to repeated use of diluted sulfuric acid. was there. Therefore, recently, a group of electrode plates assembled in an unformed state is inserted into a battery case, a top cover is attached, and then a predetermined amount of dilute sulfuric acid electrolyte is injected from the injection port, and the required amount of electricity is supplied (electricity method) Tank formation) is widely used.

However, this battery case formation has the following problems. One is the generation of cracks in the active material during electrode plate processing. That is, the electrode plate in the filling process of filling the active material into the lattice substrate is provided with a discarding ear portion for transport for filling, and it is necessary to cut off the discarding ear portion before the formation.
In multi-chamfer handling of a plurality of electrode plates on one surface obtained by connecting a plurality of substrates to each other by their feet or the like by one casting, it is necessary to further cut to a predetermined storage battery size. Due to the lattice deformation due to the cutting stress, the active material with poor adhesion is likely to crack and drop off from the lattice. In particular, since the thickness of the negative electrode plate is relatively small, the tendency is large, and the damage of the active material is likely to expand in the subsequent processes.

The second is the occurrence of an internal short circuit in a storage battery using this electrode plate. The positive electrode plate usually has a connection ear on one side of the upper part of the substrate, and a foot for supporting the bottom on the lower side opposite to this in order to secure an expansion absorption space of the grid in use as a storage battery. This also applies to the negative electrode plate. When inserting the electrode plate group in which these positive and negative electrode plates are laminated via the separator into the battery case in a moderately compressed state, the electrode plate group is pushed to the end, but if it is slightly looser than the predetermined group pressure, at the end of the insertion It falls due to its own weight and collides with the bottom of the battery case. In particular, in a large stationary valve-type lead-acid storage battery for industrial use, this tendency becomes remarkable because the weight of the electrode plate group is large. Therefore, the lattice in the vicinity of the foot portion of each electrode plate where the impact is concentrated is deformed, and further damage such as generation of cracks of the active material and dropping off from the lattice is expanded. Also, the bent negative electrode grid may break through the separator and come into contact with the positive electrode grid. If the battery case is formed in this state, an internal short circuit occurs during the formation and the formation does not increase, and if the internal short circuit is slight, a problem such as a shortening of the lifespan early after the product is produced is not preferable.

  As a countermeasure, it is disclosed that reinforcing beams are provided obliquely inside the corners on the ear side of the outer frame portions of a plurality of pairs of lattice substrates. (Patent Document 1)

Further, it is disclosed that a fine lattice is further added between middle lattices at the upper and lower portions of the lattice for the function of holding the active material. (Patent Document 2)
JP-A-2-92659 Japanese Patent Laid-Open No. 6-23760

However, the lattice substrate described in Patent Document 1 is characterized by including a support beam for preventing the bending of the ear portion when the electrode plate is cut, and does not solve the problem of the present application. In addition, the purpose of the grid substrate described in Patent Document 2 is to improve current collection efficiency and strap weldability, and the grid between the vertically arranged vertical grids is too wide in the lower part (and part of the upper part). Therefore, it supplements the retention of the active material and has the effect of reinforcing the foot, but it still does not solve the problem of the present application.

  Therefore, the present invention provides a control valve type lead-acid battery that prevents the active material from cracking or dropping off at the upper part of the foot of the negative electrode filling plate and preventing internal short circuit at the foot of the electrode plate group by this negative electrode. is there.

According to the present invention, in a negative electrode grid substrate for a lead storage battery comprising lead or a lead alloy as a main component and including a foot portion, the width of the foot portion is larger than the width of the foot portion of the positive electrode plate, and the following 1) to 3 ), That is,
1) Add at least one reinforcing grid within the grid of the grid located at the top of the foot.
2) Thicken at least one of the medium lattices constituting the meshes located at the upper part of the foot.
3) Thicken the frame lattice that forms the lower part of the mesh located above the foot part.
It comprises at least one of the following structures.

  Although the object of the present invention is to prevent a short circuit by reinforcing the foot portion of the negative electrode plate, the improvement effect for the prevention of the short circuit is insufficient only by adding a reinforcing grid as in Patent Document 1 described above. Further, simply increasing the number of reinforcing grids causes problems such as a loss of castability of the grids and a reduction in the space for filling the active material.

  Therefore, the aim is a synergistic effect that combines the increase in the width of the foot that can ensure both the space for filling the active material and the castability of the lattice, and the reinforcement of the intermediate lattice. Thereby, even when the electrode plate group is inserted, even if the foot portion of the thin negative electrode plate collides with the bottom of the battery case, the deformation does not occur, thereby preventing an internal short circuit.

  If the width of the foot portion of the negative electrode plate is too large, the weight increases but the effect does not change. Therefore, the width is preferably within twice the width of the foot portion of the positive electrode plate.

Further, in the above three items of reinforcement measures, the lattice to be reinforced may be a vertical lattice, a horizontal lattice, or an oblique lattice. The lattice to be added is limited to about 50% or less of the original active material filling space, and the cross-sectional dimension to be thickened is preferably equal to or about twice as large as the middle lattice.

In addition, the range of the reinforcement site | part to add or thicken should just contain the 1 or more steps | paragraph of the upper part of a foot part, and the 1 or more grid | lattice of the right and left.

  Furthermore, as a method of the present invention, the positive electrode plate has one foot on the lower side opposite to the ear portion, but the negative electrode plate has two foot portions on the left and right sides, or these positive and negative electrode plate feet are mutually connected. The present invention can also be implemented by a configuration in which they are shifted from each other at positions that do not face each other.

In addition, the group pressure when the electrode plate group according to the present invention is inserted into the battery case may be higher than that of the conventional case, but if it is excessively high, defects due to turning up of the end plate may occur, or the separator may be excessively compressed. Since an internal short circuit occurs, the range of 40 to 80 kPa is preferable.

  According to the present invention, the negative electrode plate can be prevented from being damaged without significantly changing the lattice design and suppressing the increase in weight as much as possible. Therefore, the negative electrode plate is short-circuited due to penetration of the separator or dropping of the active material from the electrode plate group. Therefore, it is possible to provide a control valve type lead storage battery having a reduced initial failure rate.

  As an embodiment of the present invention, first, 20 negative electrode substrates each having the configuration shown in Table 1 are prepared and filled with an active material paste obtained by kneading a predetermined amount of water and dilute sulfuric acid in a normal process. Then, aging and drying were carried out to produce negative electrode-filled plates of Examples 1 to 3, Comparative Examples 1 and 2, and Conventional Example 1.

  As shown in FIG. 1, the negative electrode substrate of Embodiment 1 is made of lead or lead formed in a lattice shape by allowing a large number of vertical and horizontal medium lattices 12 to go straight in a space surrounded by a vertically long rectangular frame lattice 11. In the negative electrode lattice substrate 1 made of lead alloy to which tin or tin is added, an ear portion 13 protruding upward is formed at one side end portion of the frame lattice 11 located at the upper portion, and the frame lattice 11 located at the lower portion is disposed below The leg portion 14 is formed to be wider than the foot portion of the positive grid substrate formed in the same manner, and the reinforcing grid is formed in the mesh 15 formed immediately above the wide foot portion 14. 16 is formed. The foot 14 is formed on the side opposite to the ear 14.

  As shown in FIG. 2, the negative electrode substrate of Embodiment 2 is a first grid of one vertical middle grid 12 positioned just above the wide foot 14 instead of forming a reinforcing grid in the grid. The negative electrode substrate according to the third embodiment, which is formed in the same manner as in Example 1 except that only the portion is thickened to form the reinforcing grid 16, is positioned immediately above the wide foot portion 14 as shown in FIG. Instead of thickening the vertical middle grid 12, the lower frame grid 11 on which the wide leg portions 14 are formed is a portion of the first grid located immediately above the wide leg portions 14. It was formed in the same manner as in Example 2 except that only the reinforcing grid 16 was made thicker.

  As shown in FIG. 4, the negative electrode substrate of Comparative Example 1 was formed in the same manner as in Example 1 except that the width of the foot portion 14 was the same as the width of the foot portion of the positive electrode substrate. As shown in FIG. 5, the width of the foot 14 is made larger than that of the positive electrode substrate, but the reinforcing grid is not formed and the same as in Example 1, the negative electrode substrate of Conventional Example 1 is shown in FIG. As shown in FIG. 6, the width of the foot portion 14 is the same as that of the positive electrode substrate, and no reinforcing grid is formed. In the drawings, some of them are omitted.

Each of these negative electrode grid substrates is obtained by casting a lead alloy. Around the periphery thereof, a throwing-away portion of a conveyance is integrally cast, and in this state is filled with an active material. And processed into an electrode plate.

  Then, using these processed electrode plates, as shown in FIG. 7, the positive electrode substrate further includes one piece so that the ear portion 13 of the negative electrode substrate is located on the side opposite to the ear portion 23 of the positive electrode substrate. Each of the foot portions 24 and the one foot portion 14 of the negative electrode substrate is positioned on the opposite side, and each of the 26 negative electrode plates and 25 positive electrode plates are alternately laminated via a retainer mat, An electrode plate group composed of 25 positive electrodes and 26 negative electrodes was assembled, and inserted into a battery case at a group pressure of 40 kPa. Further, a lid was attached, a predetermined amount of dilute sulfuric acid electrolyte was injected by a conventional method, and a battery case was formed, and 20 control valve type lead storage batteries of 2V-1000 Ah were produced using each negative electrode plate. According to the used negative electrode plate, the batteries of Embodiments 1 to 3, Comparative Examples 1 and 2, and Conventional Example 1 were designated as A to F, respectively.

  In addition, you may form not only one leg | foot part of a negative electrode board | substrate but 2 or more. In this case, it is not necessary to make the width of all the foot portions larger than the width of the positive foot portion, and at least one of them should be made larger, and a reinforcing grid may be formed in the mesh just above the enlarged foot portion.

  After each of the 10 batteries A to F was formed, replenishment and recharging were performed, the capacity was confirmed at a rate of 10 hours, and the open voltage was measured after 24 hours from charging to 120% of the discharge amount again. As a result, the total number of batteries A to C was 2.16V, and in battery D, nine were 2.16V and one was 2.11V. Further, in the battery E, 8 pieces were 2.16V, 2 pieces were 2.12V, and in the battery F, 7 pieces were 2.16V, 2 pieces were 2.11V, and one piece was 2.12V.

  Next, in order to compare the difference in the amount of decrease in the open circuit voltage of each battery and to select the internal short circuit battery, each of the 10 batteries A to F is left in a 25 ° C. atmosphere for 2 weeks, and then the open circuit voltage again. Was measured. As a result, both batteries A and B were 2.15V. In battery C, nine were 2.15V and one was 2.14V, and in battery D, nine were 2.15V and one was 2.10V. In addition, 8 pieces of battery E are 2.15V, 2 pieces are 2.10V and 2.11V, respectively, 7 pieces of battery E are 2.15V, 2 pieces are 2.10V, and 1 piece is 2.11V. It was. Therefore, when the battery E and the battery F were disassembled and investigated for a large drop in open circuit voltage of 0.03 V or more from the initial stage, an internal short circuit due to the active material dropped off at the bottom of the electrode plate group was observed. On the other hand, in the dismantling investigation of the batteries A to C, the formation of the electrode plate was good and there was no internal short circuit. The results are shown in Table 1 as the number of short circuits.

  By using the present invention, it is possible to prevent an internal short circuit at the foot of the negative electrode, and a highly reliable control valve type lead storage battery can be provided at low cost.

FIG. 3 is a diagram in which a part of the negative electrode lattice substrate of Embodiment 1 is omitted. It is the figure which abbreviate | omitted and showed the negative electrode grid substrate of Embodiment 2. FIG. It is the figure which abbreviate | omitted and showed the negative electrode grid substrate of Embodiment 3. FIG. It is the figure which abbreviate | omitted and showed the negative electrode grid substrate of the comparative example 1. FIG. It is the figure which abbreviate | omitted and showed the negative electrode grid substrate of the comparative example 2. FIG. It is the figure which abbreviate | omitted and showed the negative electrode grid substrate of the prior art example 1. FIG. It is a partial abbreviation figure explaining the state which laminated | stacked the negative electrode grid substrate and the positive electrode grid substrate.

Explanation of symbols

1 Negative grid substrate 11 Frame grid
12 Middle lattice 13 Ear portion 14 Foot portion 16 Reinforced lattice

Claims (2)

In a negative electrode grid substrate for a lead storage battery comprising lead or a lead alloy as a main component and having a foot portion, the width of the foot portion is larger than the width of the foot portion of the positive electrode plate, and the lattice located above the foot portion Add at least one reinforcing grid inside the mesh, or make at least one of the middle grids that make up the mesh located at the top of the foot thicker, or configure the bottom of the mesh located at the top of the foot A negative electrode grid substrate for a lead storage battery, characterized in that it has at least one configuration of making the frame grid thicker. A control valve type lead storage battery comprising the negative electrode grid substrate according to claim 1.

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