JP5866702B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a lead-acid battery.

  When a lead storage battery using an expanded grid for the positive electrode plate is used in a high temperature environment, various ideas have been devised in order to extend the life of the lead storage battery.

For example, in Patent Document 1, the area of one mesh is 40 mm ² or more and 150 mm ² or less (the width of the mesh is 11.0 mm or more and 23.0 mm or less). Techniques for preventing this are described.

  Patent Document 2 describes a technique for avoiding corrosion and stress concentration of the positive grid by reducing the thickness of the lead alloy sheet before expanding to a thickness greater than 1.0 mm and less than 1.3 mm. ing.

JP 11-339788 A JP 2001-006686 A

  Patent Document 1 defines a preferable configuration condition for extending the life under a condition where the discharge depth is as deep as 40% in an environment of 40 ° C. On the other hand, Patent Document 2 defines suitable conditions for extending the life under light load conditions in an environment of 75 ° C.

  However, lead-acid batteries for starting automobiles have recently increased in use under conditions where temperatures are far above 40 ° C. and deep charge / discharge is repeated. Under such severe conditions, even if the techniques described in Patent Document 1 and Patent Document 2 are applied, sufficient life characteristics cannot be obtained.

  The present invention has been made in view of such problems, and its main object is to provide a lead-acid battery having sufficient life characteristics even under severe conditions in which deep charge / discharge is repeated at high temperatures. It is in.

A lead storage battery according to the present invention includes a positive electrode plate composed of a positive electrode active material and a positive electrode lattice, a negative electrode plate composed of a negative electrode active material and a negative electrode lattice, with a separator interposed therebetween, and an electrode plate group. The positive grid is composed of an expanded grid formed by developing a lead alloy sheet, and the expanded grid has an upper frame bone and a mesh composed of the grid bone, and the lead alloy before deployment. The sheet thickness is: 2 mm or more It is 5 mm or less, and the width | variety of the mesh which consists of lattice bones is 7 mm or more and 18 mm or less. Here, the width of the mesh composed of lattice bone refers to the distance between two adjacent nodule portions in a direction substantially perpendicular to the direction of expansion of the expanded lattice.

  ADVANTAGE OF THE INVENTION According to this invention, the lead acid battery which has sufficient lifetime characteristics can also be provided under the severe conditions where deep charging / discharging is repeated under high temperature.

The figure which showed the lead acid battery of this invention typically The figure which showed the structure of the positive electrode grid of the lead acid battery of this invention typically The figure which showed typically the other structure of the positive electrode grid of the lead acid battery of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention.

  FIG. 1 is a diagram schematically showing a configuration of a lead storage battery according to an embodiment of the present invention.

  As shown in FIG. 1, the electrode plate group 1 is formed by laminating a positive electrode plate 1a composed of a positive electrode active material and a positive electrode lattice 4, and a negative electrode plate 1b composed of a negative electrode active material and a negative electrode lattice via a separator 1c. Configured. The battery case 2 that accommodates the electrode plate group 1 includes a plurality of cell chambers 2 a that are internally partitioned by an intermediate partition plate 2 b and that accommodate the electrode plate groups 1, respectively. The plurality of electrode plate groups 1 are connected in series by connecting different electrode plates of the electrode plate group 1 accommodated in the adjacent cell chamber 2a. Each electrode plate of the electrode plate group 1 at both ends is connected to a terminal 3 a that protrudes from the lid 3 that covers the opening of the battery case 2. An electrolyte is injected into each cell chamber 2a from a liquid port (not shown), and the liquid port is sealed with a liquid port plug 3b.

  2 and 3 are diagrams schematically showing the configuration of the positive electrode lattice 4 of the lead storage battery in the present embodiment, FIG. 2 is a positive electrode lattice formed by a reciprocating method, and FIG. 3 is a positive electrode formed by a rotary method. Shows the grid.

  As shown in FIGS. 2 and 3, the positive grid 4 is composed of an expanded grid formed by cutting a lead alloy sheet and the expanded grid is a mesh 4c composed of an upper frame bone 4a and a grid bone 4b. And have.

  The thickness of the lead alloy sheet before unfolding substantially corresponds to the width of the lattice bone 4b in the reciprocating method shown in FIG. 2, and substantially corresponds to the thickness of the lattice bone 4b in the rotary method shown in FIG. In any method, the thickness of the ear portion 4d corresponds to the thickness of the lead alloy sheet before deployment.

  This embodiment is characterized in that the lead alloy sheet before deployment has a thickness of 1.15 mm or more and 1.6 mm or less, and the width W of the mesh 4c made of the lattice bone 4b is 5 mm or more and 20 mm or less. To do. Here, as shown in FIGS. 2 and 3, the width W of the mesh 4c refers to the distance between two adjacent nodes that are adjacent to each other in a direction substantially orthogonal to the mesh development direction of the expanded lattice.

  For a long time in emerging countries belonging to tropical and subtropical climates, automobiles have been used as high-end products and are rarely used and often placed in the shade (under the roof, etc.) after use. However, as automobiles spread in these emerging countries, automobiles have been used as a general-purpose product for a long time under hot weather, and are not always placed in the shade after use. Thus, when an automobile is overworked beyond conventional assumptions, different deterioration modes are added to the main cause of deterioration of a lead storage battery which is one of in-vehicle components. That is the “sudden death” when a lead-acid battery suddenly fails during use due to an internal short circuit.

  In the case of sudden death, when an expanded lattice that is not surrounded by a frame bone is adopted for the positive electrode lattice 4, the lattice bone 4b is easily stretched by use under high temperature, and the negative electrode plate in which the elongated lattice bone 4b is a counter electrode It is a degradation mode that reaches 1b and causes an internal short circuit. Such a deterioration mode has been known for a long time, but conventionally, it has not been possible to assume a use environment in which such a deterioration mode becomes a main factor of deterioration of a lead-acid battery. Therefore, the configuration of the expanded lattice of the positive electrode lattice 4 corresponding to such a deterioration mode has not been optimized.

  As a result of intensive studies by the present inventors, it was estimated that sudden death is the main degradation mode when multiple severe environments overlap. Specifically, not only in climatic conditions (tropical or subtropical), but also in an environment where lead-acid batteries are randomly placed near the heating elements (engines, etc.) and the amount of heat from the heating elements is added, When the engine was stopped and the cell starter was restarted many times due to self-judgment or malfunction, it was estimated that sudden death would become the main deterioration mode when deep charge / discharge was repeated. That is, under such a high temperature and a severe condition in which deep charging / discharging is repeated, the deformation of the lattice bone 4b is repeated according to the depth and number of charging / discharging, thereby distorting the lattice bone 4b. It was estimated that sudden death would become the main deterioration mode.

  As a result of various investigations, the inventors of the present application have found that the optimum of the expanded lattice used as a positive electrode lattice does not deteriorate due to sudden death even under severe conditions where high-temperature and deep charge / discharge are repeated. As a constitution, the following conditions were found.

  The first condition is that the thickness of the lead alloy sheet before being used for the positive grid 4 is 1.15 mm or more and 1.6 mm or less, more preferably 1.2 mm or more and 1.5 mm or less. . By making the thickness of the lead alloy sheet 1.15 mm or more, more preferably 1.2 mm or more, the thickness (cross-sectional area) of the lattice bone 4 b is relatively increased to give rigidity, and elongation does not easily occur. It becomes like this. On the other hand, when the thickness of the lead alloy sheet is 1.6 mm or less, more preferably 1.5 mm or less, the expansion process can be performed without difficulty, and the stress strain of the lattice bone 4b that causes the strain elongation to be far away. Can be difficult to cause.

  The second condition is that the width of the mesh 4c made of the lattice bone 4b is 5 mm or more and 20 mm or less, more preferably 7 mm or more and 18 mm or less. By setting the width of the mesh 4c to 5 mm or more, more preferably 7 mm or more, the expansion process can be performed without difficulty, and the stress distortion of the lattice bone 4b, which is a cause of the distorted elongation, can be hardly caused. On the other hand, by setting the width of the mesh 4c to 20 mm or less, more preferably 18 mm or less, the gap between the lattice bones 4b does not become excessive, the rigidity of the positive electrode lattice 4 as a whole increases, and the elongation of each lattice bone 4b increases. Less likely to occur.

  In the present invention, the composition of the lead alloy sheet used for the positive electrode grid 4 is not particularly limited, but is preferably a lead alloy containing at least calcium and tin, for example, a lead-calcium-tin alloy. Here, the content of calcium is preferably in the range of 0.02 to 0.10% by mass, and the content of tin is preferably in the range of 1.0 to 2.0% by mass.

  Hereinafter, although the example and the example of the present invention are given and the composition and effect of the present invention are further explained, the present invention is not limited to these examples.

(1) Production of lead acid battery The lead acid battery produced in the present example is a D26L type size specified in JIS D5301, and is a lead acid battery for starting an automobile having the configuration shown in FIG.

  The positive electrode plate 1a was prepared by kneading lead oxide powder with sulfuric acid and purified water to prepare a paste, and filling this paste into a positive electrode lattice 4 made of a Pb alloy containing Ca and Sn. The negative electrode plate 1b is prepared by adding an organic additive or the like to lead oxide powder and kneading with sulfuric acid and purified water to prepare a paste, and filling the paste into a negative electrode lattice made of a Pb alloy containing Ca and Sn. Produced. As the positive electrode lattice 4 and the negative electrode lattice, an expanded lattice in which a mesh 4c composed of the lattice bone 4b is developed under the upper frame bone 4a is used.

After the produced positive electrode plate 1a and negative electrode plate 1b are aged and dried, the negative electrode plate 1b is accommodated in a polyethylene bag-like separator 1c, and alternately stacked with the positive electrode plates 1a, and the seven positive electrode plates 1a and the eight negative electrode plates are stacked. The electrode plate group 1 in which 1b was laminated via the separator 1c was produced. This electrode plate group 1 was accommodated in cell chambers 2a partitioned into six, and six cells were directly connected. Further, an electrolytic solution made of dilute sulfuric acid having a density of 1.28 g / cm ³ was placed in the cell chamber 2a for chemical conversion to obtain a lead-acid battery for starting an automobile.

  In this example, as shown in Table 1, the batteries A-1 to A-7 in which the thickness of the lead alloy sheet before deployment (corresponding to the thickness of the ear portion 4d) was changed, and the width W of the mesh 4c were set. Modified batteries B-1 to B7 were produced. The change of the width W of the mesh 4c was performed by changing the conditions for cutting the lead alloy sheet.

(2) Life characteristics The formed battery was kept at 75 ° C., continuously discharged for 5 seconds at a rated cold cranking current (490 A), and the voltage at the 5th second was recorded as an initial value. Thereafter, while maintaining the battery at 75 ° C., discharging (current 25 A, time 120 seconds) and charging (voltage 14.8 V, limiting current 25 A, time 600 seconds) are repeated, and the rated cold battery is charged every 480 cycles. A continuous discharge was performed at a ranking current (490 A) for 5 seconds, and the voltage at the 5th second was recorded. When it was confirmed that the voltage at the 5th second was 7.2 V or less and it did not rise again, it was considered that the lifetime was reached, and the number of cycles until reaching the lifetime was measured.

  As shown in Table 1, the battery A-1 having a lead alloy sheet with a thickness of 1.1 mm had a very low number of cycles that reached the end of its life. This is because the lattice bone 4b has a small thickness (cross-sectional area) and lacks rigidity, and as a result of repeated deep charge and discharge at a high temperature of 75 ° C., the lattice bone 4b of the positive electrode lattice extends, This is thought to be due to reaching the negative electrode plate 1b and causing an internal short circuit.

  Further, the battery A-7 having a lead alloy sheet thickness of 1.7 mm also had a very low cycle number. This is because the lead alloy sheet has a large thickness, and therefore, an unreasonable expansion process is performed. As a result, a stress strain is generated in the lattice bone 4b, resulting in a deep filling at a high temperature of 75 ° C. As a result of repeated discharge, it is considered that the lattice bone 4b was distorted and extended, reached the negative electrode plate 1b as the counter electrode, and caused an internal short circuit.

  On the other hand, in the batteries A-2 to A-6 in which the lead alloy sheet had a thickness of 1.15 to 1.6 mm, the life characteristics were remarkably superior to those of the batteries A-1 and A-7. These batteries reached the end of their service life due to, for example, dropping of the positive electrode active material from the positive electrode grid, and no deterioration mode (sudden death) due to internal short circuit was observed.

  From the above results, the lead alloy sheet before deployment is the optimum configuration of the expanded lattice used as a positive electrode lattice, which does not deteriorate due to sudden death even under severe conditions where high-temperature and deep charge / discharge are repeated. Is preferably 1.15 mm or more and 1.6 mm or less. In addition, as shown in Table 1, the life characteristics can be further improved by setting the thickness of the lead alloy sheet before deployment to 1.2 mm or more and 1.5 mm or less.

  Further, as shown in Table 1, the battery B-1 in which the mesh 4c of the positive electrode lattice 4 had a width W of 4 mm had a very low cycle number. This is because the mesh 4c has a small width W, and therefore, an unreasonable expansion process is performed. As a result, a stress strain is generated in the lattice bone 4b, and as a result, the mesh 4c is deeply filled at a high temperature of 75 ° C. As a result of repeated discharge, it is considered that the lattice bone 4b was distorted and extended, reached the negative electrode plate 1b as the counter electrode, and caused an internal short circuit.

  Further, the battery B-7 in which the mesh 4c of the positive electrode grid 4 had a width W of 21 mm also had a very low number of cycles that reached the end of its life. This is because the width W of the mesh 4c is large, the interval between the lattice bones 4b becomes excessive, the rigidity of the positive electrode lattice 4 as a whole becomes low, and deep charge / discharge is repeated at a high temperature of 75 ° C. As a result, it is considered that the lattice bone 4b of the positive electrode lattice extended and reached the negative electrode plate 1b as the counter electrode, causing an internal short circuit.

  On the other hand, in the batteries B-2 to B-6 in which the width W of the mesh 4c of the positive electrode lattice 4 is 5 to 20 mm, the life characteristics are remarkably superior to those of the batteries B-1 and B-7. These batteries reached the end of their service life due to, for example, dropping of the positive electrode active material from the positive electrode grid, and no deterioration mode (sudden death) due to internal short circuit was observed.

  From the above results, the mesh 4c of the positive electrode lattice 4 is an optimum configuration of the expanded lattice used as the positive electrode lattice, which does not deteriorate due to sudden death even under severe conditions in which deep charge / discharge is repeated at high temperatures. Preferably, the width W is 5 mm or more and 20 mm or less. In addition, as shown in Table 1, the life characteristics can be further improved by setting the width W of the mesh 4c of the positive electrode lattice 4 to 7 mm or more and 18 mm or less.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

  The present invention is useful for lead acid batteries used at high temperatures.

DESCRIPTION OF SYMBOLS 1 Electrode plate group 1a Positive electrode plate 1b Negative electrode plate 1c Separator 2 Battery case 2a Cell chamber 2b Middle partition plate 3 Lid 3a Terminal 3b Liquid port plug 4 Positive electrode lattice 4a Upper frame bone 4b Lattice bone 4c Mesh 4d Ear part

Claims (4)

An electrode plate group in which a positive electrode plate made of a positive electrode active material and a positive electrode lattice, and a negative electrode plate made of a negative electrode active material and a negative electrode lattice are laminated via a separator;
A battery case for housing the electrode plate group;
A lead-acid battery comprising
The positive grid is composed of an expanded grid formed by developing a lead alloy sheet,
The expanded lattice has an upper frame bone and a mesh made of lattice bone,
The thickness of the lead alloy sheet before deployment is 1.2 mm or more and 1.5 mm or less,
In a direction substantially perpendicular to the deployment direction of the mesh of the expanded grid, when the width of the mesh comprising the distance between the two nodal portions adjacent to each other from the grating bone, the width of the mesh consisting of the grating bone Lead acid battery which is 7 mm or more and 18 mm or less. The thickness of the lead alloy sheet before deployment is 1.3 mm or more and 1.5 mm or less,
The lead acid battery according to claim 1, wherein a width of the mesh made of the lattice bone is 7 mm or more and 16 mm or less.   The lead storage battery according to claim 1, wherein the lead alloy sheet includes at least calcium and tin.   The lead acid battery according to any one of claims 1 to 3, wherein the lead acid battery is a lead acid battery for starting an automobile.