Lead-acid battery for auxiliary machine

Abstract

To provide a lead-acid battery for an auxiliary machine that can effectively prevent short-circuit caused by occurrence of growth in a positive electrode current collector and avoid excess gas buildup inside a battery, thereby improving safety.SOLUTION: A lead-acid battery for an auxiliary machine has a battery case H having a plurality of cell chambers C in which an electrolyte and an electrode plate group are respectively accommodated. The electrode plate group has a laminate consisting of a plurality of positive and negative electrode plates 10 and 20 arranged alternately, and separators 30 arranged between the positive and negative plates 10 and 20. The positive electrode plate 10 has a positive electrode current collector and a positive electrode mixture containing a positive electrode active material, and the negative electrode plate 20 has a negative electrode current collector and a negative electrode mixture containing a negative electrode active material. The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, and the tensile strength of the separator 30 after a high-temperature overcharge test is 3.0 N / mm2 or more.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Embodiments of the present invention relate to a lead storage battery for auxiliary equipment.

Background Art

[0002] In recent years, in order to cope with the worsening environmental problems and exhaust gas regulations, for example, hybrid vehicles and electric vehicles (hereinafter referred to as "EV vehicles") have become popular. Since an EV vehicle uses electrical energy from a storage battery (such as a lead storage battery or a lithium ion secondary battery) as a power source, the amount of exhaust gas can be reduced.

[0003] However, with regard to the lead storage battery mounted on an EV vehicle as described above, it is often used as a power supply for electrical components mounted on the vehicle, and there is also an example in which a lead storage battery for starting the engine and a lead storage battery for a vehicle system including various electrical components (hereinafter, such a lead storage battery is referred to as a "lead storage battery for auxiliary equipment") are provided separately. Also, in this case, the performance of the lead storage battery for auxiliary equipment is different from that for engine starting.

[0004] And the lead storage battery for auxiliary equipment is mainly arranged not in the engine room but in the trunk room or a place closer to the passenger compartment. Therefore, the gas discharged during charge and discharge is discharged outside the vehicle through, for example, a tube. Also, in order to prevent such gas from being discharged in the first place, for example, a control valve type lead storage battery as disclosed in the following patent documents may be used.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, at present, technology has also advanced. As for the types of lead-acid batteries used as auxiliary batteries, for example, it is not necessarily required to be a controlled valve type lead-acid battery as disclosed in Patent Document 1 described above. For example, a liquid type lead-acid battery may be used.

[0007] In a lead-acid battery, when the positive electrode and the negative electrode come into contact, a short circuit occurs, and when a short circuit occurs, a gas in an amount exceeding the normal exhaust capacity is generated. Therefore, it is crucial to prevent short circuits as much as possible so that excessive gas does not occur.

[0008] Here, the lead-acid battery as described above includes, for example, a plurality of positive electrode plates and negative electrode plates alternately arranged inside a battery case, and a separator arranged between the positive electrode plate and the negative electrode plate, and a plate group composed of a laminate provided with the separator is immersed in an electrolytic solution.

[0009] In a lead-acid battery, the positive electrode current collector (positive electrode grid) undergoes grain boundary corrosion due to repeated oxidation-reduction reactions of charging and discharging, resulting in elongation (growth). Here, when the elongation (growth) of the positive electrode grid progresses, the positive electrode grid may break through the seal portion on the side surface of the separator and come into contact with the negative electrode plate, increasing the possibility of a short circuit and leading to an early life.

[0010] An object of the present invention is to provide an auxiliary lead-acid battery capable of effectively preventing a short circuit caused by the occurrence of growth in a positive electrode current collector and improving safety by avoiding the generation of excessive gas inside the battery.

Means for Solving the Problems

[0011] The auxiliary lead-acid battery according to one aspect of the present invention has a battery case having a plurality of cell chambers for accommodating an electrolytic solution and a group of electrode plates respectively. The group of electrode plates includes a laminate composed of a plurality of positive electrode plates and negative electrode plates arranged alternately, and a separator arranged between the positive electrode plate and the negative electrode plate. The positive electrode plate has a positive electrode current collector and a positive electrode mixture containing a positive electrode active material, and the negative electrode plate has a negative electrode current collector and a negative electrode mixture containing a negative electrode active material. The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, and the tensile strength of the separator after a high-temperature overcharge test is 3.0 N / mm 2 or more.

Advantages of the Invention

[0012] According to the present invention, the auxiliary lead-acid battery according to one aspect of the present invention has a battery case having a plurality of cell chambers for accommodating an electrolytic solution and a group of electrode plates respectively. The group of electrode plates includes a laminate composed of a plurality of positive electrode plates and negative electrode plates arranged alternately, and a separator arranged between the positive electrode plate and the negative electrode plate. The positive electrode plate has a positive electrode current collector and a positive electrode mixture containing a positive electrode active material, and the negative electrode plate has a negative electrode current collector and a negative electrode mixture containing a negative electrode active material. The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, and the tensile strength of the separator after a high-temperature overcharge test is 3.0 N / mm 2 or more. Therefore, it is possible to effectively prevent a short circuit caused by the growth in the positive electrode current collector and avoid the generation of excessive gas inside the battery, thereby improving safety.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below shows an example of the present invention. Also, various changes or improvements can be made to these embodiments, and forms with such changes or improvements can also be included in the present invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0015] FIG. 1 is a diagram showing a schematic structure of a lead-acid battery B according to an embodiment of the present invention, showing a state where the lid is removed from the battery case H. In FIG. 1, the drawing of the lid is omitted. FIG. 2 is a partial cross-sectional view of the lead-acid battery B according to an embodiment of the present invention.

[0016] As shown in FIG. 1, the lead-acid battery B according to an embodiment of the present invention includes a battery case H, a lid (not shown), and six electrode plate groups 1. The shape of the battery case H is a rectangular parallelepiped, and the battery case H has a pair of first walls H1 formed on a pair of long sides of the rectangular bottom surface and a pair of second walls H2 formed on a pair of short sides. The inside of the battery case H is partitioned into six cell chambers C by five partition walls P parallel to the second walls H2. One electrode plate group 1 is disposed in each of the six cell chambers C.

[0017] As shown in FIG. 2, in the plate group 1 in the lead storage battery B according to the embodiment of the present invention, a plurality of positive plates 10 and negative plates 20 are alternately stacked via a separator 30 with ribs. The plate group 1 is accommodated in the cell chamber C of the battery case H together with an electrolyte (not shown) such that the stacking direction thereof is along the horizontal direction (that is, the plate surfaces of the positive plate 10 and the negative plate 20 are along the vertical direction (Z direction)). And the plate group 1 is immersed in the electrolyte in the cell chamber C of the battery case H.

[0018] That is, the lead storage battery B according to the embodiment of the present invention has the plate group 1 and a battery case H having a cell chamber C that accommodates the plate group 1 together with the electrolyte, and one plate group 1 is accommodated in one cell chamber C. The number of positive plates 10 constituting the plate group 1 is equal to or greater than the number of negative plates 20.

[0019] The positive plate 10 has a current collector for positive electrode and a positive electrode mixture containing a positive electrode active material, and the positive electrode active material contains lead dioxide. The current collector for positive electrode has a rectangular lattice-shaped substrate and an ear part 11 continuous with the lattice-shaped substrate, and the positive electrode mixture is held on the lattice-shaped substrate to form the positive plate 10. On the other hand, the negative plate 20 has a current collector for negative electrode and a negative electrode mixture containing a negative electrode active material, and the negative electrode active material contains metallic lead. The current collector for negative electrode has a rectangular lattice-shaped substrate and an ear 21 continuous with the lattice-shaped substrate, and the negative electrode mixture is held on the lattice-shaped substrate to form the negative plate 20.

[0020] And the positive electrode mixture and the negative electrode mixture are filled in the openings of the respective lattice-shaped substrates and exist as active material layers on both plate surfaces of the lattice-shaped substrates.

[0021] The separator 30 is, for example, a porous membranous body made of resin, glass, or the like. And it has a flat base surface and a rib-shaped rib protruding in a direction perpendicular to the surface direction of the base surface as needed.

[0022] The ears 11 of a plurality of the positive electrode plates 10 described below are connected by a positive electrode strap 13, and the ears 21 of a plurality of the negative electrode plates 20 are connected by a negative electrode strap 23. Then, the positive electrode strap 13 is connected to one end of a positive electrode terminal (not shown), and the negative electrode strap 23 is connected to one end of a negative electrode terminal (not shown). The other ends of the positive electrode terminal and the negative electrode terminal penetrate through a lid (not shown) that closes the opening of the battery case H and are exposed outside the case body of the lead storage battery B composed of the battery case H and the lid.

[0023] Regarding a lead storage battery having such a structure, first, a test was conducted on the ratio of the mass of the positive electrode active material to the mass of the negative electrode active material in the lead storage battery B according to the embodiment of the present invention. FIG. 3 shows the results of the test.

[0024] In FIG. 3, the test results regarding three comparative examples and three examples are shown. That is, in the column direction of the table, a total of six examples, namely Comparative Example 1 to Comparative Example 3 and Example 1 to Example 3, are shown together with their respective results. Also, in the row direction, from the left, four items, namely "Number of plates (+ / -)", "Positive electrode utilization rate (%)", "Life performance (%)", and "Active material ratio", are arranged.

[0025] First, for the lead storage batteries used in the three comparative examples and the three examples, all used European standard LN1 batteries. Also, the positive electrode grid constituting the positive electrode current collector is made of a calcium alloy containing calcium (Ca) in the range of 0.03% to 0.08% and tin (Sn) in the range of 1.2% to 2.1% respectively.

[0026] "Number of plates (+ / -)" indicates the number of each of the positive electrode plates and the negative electrode plates arranged in one cell chamber. In the item, "+" represents the positive electrode plate and "-" represents the negative electrode plate. Here, since all are shown as "5 / 5", in any of the comparative examples and examples, the number of positive electrode plates is 5 and the number of negative electrode plates is 5, which is the same.

[0027] "Positive electrode utilization rate" indicates the ratio of the total mass of the active material for the positive electrode that is utilized. For example, when the mass of the active material for the positive electrode is 100 g, if all 100 g is utilized, the utilization rate is 100%. However, if the utilization rate is set at 100%, the deterioration of lead battery B will also accelerate. Generally, the higher the utilization rate, the faster the deterioration, and the lower the utilization rate, the slower the degree of deterioration.

[0028] Therefore, when the utilization rate decreases, the elongation (occurrence of growth) of the current collector for the positive electrode can be suppressed. On the other hand, if the utilization rate is too low, the performance required for the lead battery itself cannot be exhibited.

[0029] Regarding the "positive electrode utilization rate", there are various viewpoints on what percentage of the utilization rate can achieve a balance between "reducing the possibility of short circuit due to growth" and "exhibiting the performance of lead battery B". Here, as one viewpoint (guideline), there is a viewpoint (guideline) that the positive electrode utilization rate is approximately around 50%. From this perspective, as shown in the table of Figure 3, in Examples 1 to 3, the positive electrode utilization rate is all approximately around 50%. On the other hand, in Comparative Examples 1 to 3, none of them reached 50% or greatly exceeded 50%.

[0030] Note that the "positive electrode utilization rate" shown in Figure 3 was calculated by conducting a 20-hour rate capacity test. Here, the "20-hour rate capacity test" is a test for measuring the capacity (Ah) of a lead battery when a fully charged lead battery is discharged until the discharge cut-off voltage drops to 10.5 V at a current of 1 / 20 of the 20-hour rate capacity (20-hour rate current: 0.05C) with the temperature of the electrolyte being 25°C ± 2°C.

[0031] "Life performance" was obtained by performing the cycle life test method that mainly simulates the usage of passenger cars and light commercial vehicles, and conducting the light load life test of JIS D 5301 (2006). That is, it measures the number of cycles (times) until the life is reached when repeating the cycle of discharge and charge in the light load region where the discharge amount per cycle is 9% or less of the 20-hour rate capacity C20,n.

[0032] Specifically, in a water tank at 40°C, discharging is performed at a constant current of 25.0 A for 240 seconds, and charging and discharging are performed at a constant voltage of 14.80 V (limiting current 25.0 A) for 600 seconds. One cycle consists of such charging and discharging, and 480 cycles are performed per time. And every time these 480 cycles are completed, it is left standing for 56 hours, and continuous discharging is performed for 30 seconds with the cold cranking current. The test was terminated when the voltage at the 30th second became 7.2 V or less.

[0033] When the case of Example 3 was taken as 100%, including Example 4 and Example 5, it exceeded 100%, but for Comparative Example 1 to Comparative Example 3, results that fell short of 100% were obtained.

[0034] In these three comparative examples and the three examples, the ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is different. As shown in the "active material ratio", the ratio is divided into six patterns from "1.0" to "1.5". That is, Comparative Example 1 is "1.0", Comparative Example 2 is "1.1", and Comparative Example 3 is "1.5". On the other hand, Examples 1 to 3 are set to be from "1.2" to "1.4".

[0035] Here, in order to change the ratio of the mass of the negative electrode active material to the mass of the positive electrode active material, the mass of the negative electrode active material is not changed, and the ratio is changed by increasing or decreasing the mass of the positive electrode active material.

[0036] Judging from the test results of the above-mentioned "positive electrode utilization rate" and "life performance", the results of the examples are better than those of the comparative examples. Among the three examples, the results of Example 2 and Example 3 are more preferable. That is, the ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, and more preferably, the ratio is 1.3 or more and 1.4 or less.

[0037] Next, using the lead-acid battery of Example 2 shown in FIG. 3, the specifications of the separator were verified. First, it is the specification regarding the tensile strength of the separator. FIG. 4 is a table showing the results of a test on the tensile strength of the separator 30 in the lead-acid battery B according to the embodiment of the present invention.

[0038] To obtain the test results regarding the tensile strength of the separator 30, first, a high-temperature overcharge test is performed on the lead-acid battery B. In this high-temperature overcharge test, in a water bath at 75°C, a discharge is performed at a constant current of 25.0 A for 60 seconds, and a charge and discharge at a constant voltage of 14.80 V (limiting current 25.0 A) for 600 seconds is taken as one cycle, and 609 cycles are performed per time. And every time 609 cycles are completed, it is left at 75°C for 56 hours. This 609 cycles per time are repeated 8 times to end the test.

[0039] After that, this lead-acid battery B is disassembled, and among the plurality of cell chambers, the separators in the third cell chamber and the fourth cell chamber are taken out, washed with water, and then dried. A test piece is cut out from the separator in this state. The shape of the test piece is a so-called dumbbell shape.

[0040] That is, regarding the shape of the test piece, when the test piece is placed so that its longitudinal direction is the left-right direction, two dumbbell-shaped portions are arranged at both left and right ends. And the central portion connecting the two dumbbell-shaped portions has a constricted shape. The dimensions of this constricted portion in the left-right direction and the up-down direction are 50.0 mm × 10.0 mm.

[0041] Also, when the test piece is placed in the same way so that its longitudinal direction is the left-right direction, it is cut out so that the ribs provided on the separator are arranged in the up-down direction. That is, the direction in which the test piece is pulled when performing the tensile test and the direction in which the ribs are formed are orthogonal to each other. By cutting out the test piece in this way, the tensile strength of the separator itself can be measured regardless of the strength of the ribs.

[0042] The test on the tensile strength of the separator 30 is performed by a tensile test in which a test piece is pulled in the longitudinal direction of the test piece at a displacement rate of 300 mm / min. The results of the test are shown in FIG. 4.

[0043] In this test, as described above, a tensile test is performed using the lead-acid battery B having the configuration of Example 2. That is, separately from the lead-acid battery B used in the test on the ratio of the mass of the positive electrode active material to the mass of the negative electrode active material in the lead-acid battery B according to the embodiment of the present invention, a lead-acid battery B having the configuration of Example 2 is prepared again for this test.

[0044] Here, for two comparative examples (Comparative Example 4 and Comparative Example 5) and two examples (Example 4 and Example 5), a plurality (for example, three) of lead-acid batteries B having the configuration of Example 2 are prepared respectively, and the separators are taken out from these lead-acid batteries B and used as test pieces for the test.

[0045] However, in these lead-acid batteries B of the comparative examples and examples, two different types of separators are used as the separator. That is, for the types of separators in the two comparative examples and the two examples, the same type of separator is used in the two comparative examples. Also, the same type of separator is used in each of the two examples. On the other hand, the types of separators used in the two comparative examples and the two examples are different types.

[0046] The table shown in FIG. 4 shows the results of the tensile tests performed on the two comparative examples and the two examples. Note that for both the comparative examples and the examples, a plurality of lead-acid batteries B are prepared and the tests are performed as described above. Therefore, the table in FIG. 4 shows the averaged values of the obtained results.

[0047] Next, looking at the thickness in the base portion of the separator, for the two comparative examples, separators with a thickness of 0.25 mm were used in both cases. On the other hand, the thickness in the base portion of the separator in Example 5 is 0.25 mm, and the thickness in the base portion of the separator in Example 6 is 0.20 mm. Note that the thickness of the base of the separator refers to the thickness of one side excluding the rib height.

[0048] In FIG. 4, Comparative Example 5, Comparative Example 6, Example 5, and Example 6 are shown from top to bottom in the column direction, and in the row direction, four items of "width", "maximum strength", "cross-sectional area", and "tensile strength" are shown from left to right.

[0049] "Width (mm)" indicates the length of the constricted portion in the test piece as described above, and in all cases it is "10.0 mm". "Maximum strength (N)" indicates the maximum strength applied to the test piece when the test piece is pulled at a displacement speed of 300 mm / min. The value of this "maximum strength" is different for each comparative example and example.

[0050] "Cross-sectional area (mm 2 )" is the value obtained by multiplying the above-mentioned "width" by the "thickness in the base portion". Regarding the width, it is the same length for both the comparative examples and the examples. On the other hand, regarding the "thickness", there are cases of "0.20 mm" and "0.25 mm" as described above, so the cross-sectional area values differ depending on the type of separator used.

[0051] Finally, the results of the tensile test using such test pieces are shown as "tensile strength (N / mm 2 )". The value of the tensile strength shows the average value obtained by acquiring the measurement results for each of the test pieces of the lead-acid battery B prepared in plural for the two above-mentioned comparative examples and two examples.

[0052] And FIG. 5 shows the relationship between this tensile strength and the thickness in the base portion of each separator. FIG. 5 is a table showing the results of tests using separators with different base thicknesses in the lead-acid battery B according to the embodiment of the present invention.

[0053] In FIG. 5, "Comparative Example 5", "Comparative Example 6", "Example 5", and "Example 6" are arranged in order from the top, and for each comparative example and example, the following items to be described are shown.

[0054] Also, in the table shown in FIG. 5, three items of "Separator type", "Base thickness (mm)", and "Tensile strength after test (N / mm 2 )" are arranged in the row direction. As described above, since the same separator is used in two comparative examples and two examples respectively, there are two types of separators. In the table of FIG. 5, for convenience, the type of separator used in the comparative example is represented as "A", and the type of separator used in the example is represented as "B".

[0055] Regarding "Base thickness (mm)", as described above, it is "0.25 mm" for the type of separator used in the comparative example. On the other hand, the thickness of the separator used in Example 5 is "0.25 mm", and the thickness of the separator used in Example 6 is "0.20 mm".

[0056] And looking at "Tensile strength after test (N / mm 2 )", in the case of Comparative Example 5, it is "2.8", and in the case of Comparative Example 6, it is "2.0". On the other hand, in the case of Example 5, the value is shown as "3.7", and in the case of Example 6, it is "3.5". This value represents the tensile strength shown in FIG. 4 and shows the average value of the tensile strength in two comparative examples and two examples.

[0057] That is, for example, in the case of Example 5, the average of the test results of the tensile strength is "3.7", and in the case of Example 6, it is "3.5".

[0058] That is, from FIGS. 4 and 5, first, when comparing the comparative examples and examples, the tensile strength shows a better value in the examples than in the comparative examples. And further, when comparing the two examples, Example 5 shows a better value than Example 6.

[0059] That is, from here on, the tensile strength after the high-temperature overcharge test for the separator is 3.0 N / mm 2 or more, and furthermore, it can be seen that more favorable results are obtained when the base thickness of the separator is 0.25 mm or more.

[0060] By using a lead-acid battery having a ratio of the mass of the positive electrode active material to the mass of the negative electrode active material as described above, etc., it is possible to effectively prevent a short circuit caused by the growth in the current collector of the positive electrode, and by avoiding the generation of gas inside the battery, the safety can be improved.

[0061] Note that the present invention is not limited to the above-described embodiments as they are, and is merely an example of the present invention. At the implementation stage, the components can be modified and embodied without departing from the gist thereof, and various changes or improvements can be made to the above-described embodiments. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments.

[0062] For example, some components may be deleted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined, and forms with such changes or improvements may also be included in the present invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0063] For example, in the test, a lead-acid battery in which the number of positive electrode plates and the number of negative electrode plates are both the same was used. However, it is also possible to adopt a lead-acid battery in which the number of positive electrode plates is larger than the number of negative electrode plates. That is, from the viewpoint of the positive electrode utilization rate, by increasing the number of positive electrode plates, the utilization rate of the positive electrode active material per plate can be reduced.

[0064] Particularly in the case of a lead-acid battery for auxiliary equipment like the present invention, the application is not for engine starting but for vehicle systems, and starting the vehicle system does not require a high current like when starting the engine. Therefore, even if the number of negative plates is reduced compared to the positive plates, it is still possible to cope with it.

[0065] Regarding the technology described in the embodiments of the present invention, the following configurations can also be adopted. (1) It has a battery case having a plurality of cell chambers for accommodating the electrolyte and the electrode plate group respectively, The electrode plate group includes a laminate composed of a plurality of positive plates and negative plates arranged alternately, and a separator arranged between the positive plate and the negative plate, The positive plate has a positive current collector and a positive electrode mixture containing a positive electrode active material, and the negative plate has a negative current collector and a negative electrode mixture containing a negative electrode active material, The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, The tensile strength of the separator after a high-temperature overcharge test is 3.0 N / mm 2 or more, and it is a lead-acid battery for auxiliary equipment characterized by this. (2) The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is further 1.3 or more and 1.4 or less, and it is the lead-acid battery for auxiliary equipment according to (1) above, characterized by this. (3) The base thickness of the separator is 0.25 mm or more, and it is the lead-acid battery for auxiliary equipment according to (1) or (2) above, characterized by this. (4) The number of positive plates is equal to or more than the number of negative plates, and it is the lead-acid battery for auxiliary equipment according to any one of (1) to (3) above, characterized by this.

Explanation of reference numerals

[0066] 1 ··· Electrode plate group 10 ··· Positive plate 11 ··· Ear part 12 ··· Foot part 13 ··· Positive electrode strap 20 ··· Negative plate 21 ··· Ear part 23 ··· Negative electrode strap 30 ··· Separator B ··· Lead-acid battery C ··· Cell compartment H ··· Battery case P ··· Partition wall

Claims

1. It has an electrolytic cell having a plurality of cell chambers for accommodating an electrolytic solution and a group of electrode plates respectively, The group of electrode plates includes a laminate composed of a plurality of positive electrode plates and negative electrode plates arranged alternately, and a separator arranged between the positive electrode plate and the negative electrode plate, The positive electrode plate has a current collector for the positive electrode and a positive electrode mixture containing a positive electrode active material, and the negative electrode plate has a current collector for the negative electrode and a negative electrode mixture containing a negative electrode active material, The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is 1.2 or more and 1.4 or less, The tensile strength of the separator after the high-temperature overcharge test is 3.0 N / mm ２ or more, and the auxiliary lead-acid battery is characterized by this.

2. The ratio of the mass of the positive electrode active material to the mass of the negative electrode active material is further 1.3 or more and 1.4 or less. The auxiliary lead-acid battery according to claim 1, characterized in that.

3. The base thickness of the separator is 0.25 mm or more. The auxiliary lead-acid battery according to claim 1 or claim 2, characterized in that.

4. The number of positive electrode plates is equal to or more than the number of negative electrode plates. The auxiliary lead-acid battery according to claim 1, characterized in that.

Images