WO2015045313A1

WO2015045313A1 - Lead acid storage battery

Info

Publication number: WO2015045313A1
Application number: PCT/JP2014/004687
Authority: WO
Inventors: 勤超孫; 昊 ▲呉▼; 陽隆阿部; 佐々木　健浩
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2013-09-30
Filing date: 2014-09-11
Publication date: 2015-04-02
Also published as: CN104518201A; CN104518201B

Abstract

This lead acid storage battery comprises a plurality of cells, each of which comprises an electrode plate group, an electrolyte solution and a cell chamber. The electrode plate group and the electrolyte solution are contained in the cell chamber. The electrode plate group is obtained by alternately arranging a plurality of positive electrode plates and a plurality of negative electrode plates with separators being interposed therebetween. The separators are AGM separators, and each separator has a density within the range of 117-129 g/dm³. The collectors of the positive electrode plates and/or the negative electrode plates are expanded grids, and each electrode plate is composed of projected end portions each having a projection and a flat intermediate portion between the end portions. The thickness of the end portions is larger than the thickness of the intermediate portion.

Description

Lead acid battery

The present invention relates to a lead storage battery, and specifically to a lead storage battery excellent in both life characteristics, charge efficiency characteristics, and high rate discharge characteristics.

Lead-acid batteries are not only used as power sources for starting vehicles, lighting power sources, and standby power sources, but are also widely used as main power sources, that is, as independent power sources for charging and discharging facilities. For example, electric power storage devices such as electric vehicles, electric forklifts, electric buses, electric bicycles, electric motorcycles, electric scooters, small electric mopeds, golf cars, electric locomotives, and solar batteries. In such an application, the characteristics when the lead-acid battery operates are that the current at start-up is large, the discharge current at travel is small, and the discharge time is long. At the same time, maintenance of lead-acid batteries and a long cycle life are required. In terms of extending the life of the battery, normally, the pressure applied to the electrode plate group is increased, and the positive electrode active material is suppressed by a separator, thereby suppressing the expansion of the positive electrode active material and preventing the positive electrode active material from falling off. It has become. However, as the size of the battery increases, it is necessary to change the material or increase the thickness of the battery case wall in order to strengthen the battery case. Nevertheless, it is difficult to apply and maintain an appropriate pressure on the electrode plate group. As the usage time of lead-acid batteries increases, corrosion occurs due to oxidation of the positive electrode current collector, thereby reducing the cross-sectional area of the positive electrode current collector and reducing the overall conductivity of the positive electrode plate. As a result, voltage characteristics when the battery performs high rate discharge deteriorates. When such corrosion of the positive electrode current collector proceeds, the positive electrode current collector itself is eventually broken. Therefore, the capacity of the battery is quickly reduced and the life is reached.

If the battery is repeatedly charged and discharged while the lead acid battery is in use, the battery performance gradually decreases. When the performance of the battery deteriorates, the internal pressure of the battery may increase, and a large pressure is applied between the positive electrode plate and the negative electrode plate. At this time, the electrode unit is easily compressed or deformed. That is, the electrode unit tends to be broken when the internal pressure of the battery increases.

On the other hand, with rapid progress of miniaturization and weight reduction of electronic devices, lead storage batteries used as power sources are required to have a small volume and a high charge / discharge capacity. Reducing the distance between the positive and negative electrode plates of the battery is an effective means for reducing the volume without changing the capacity. However, if the positive and negative electrode plates are too close, there is a risk of internal short circuit. When the positive electrode plate and the negative electrode plate are short-circuited, the temperature inside the battery rises, and at this time, the electrode plate group is also required to have a function of ensuring safety. Furthermore, from the viewpoint of maintaining the power characteristics and charge / discharge capacity of the battery, it is necessary to ensure the ion permeability of the electrode plate group and the performance of absorbing and maintaining the electrolytic solution.

Regarding the performance of lead-acid batteries, for example, how to improve cycle life, capacity and charge / discharge efficiency, points such as a lattice alloy and lead paste blending have already been considered. In addition, various studies have been made on the performance and structure of the electrode plate because the structure and performance of the electrode plate greatly affect the volume, power characteristics, charge / discharge capacity, and cycle life of the lead storage battery.

CN201820837U, a Chinese utility model patent, discloses a flexible paste blocking plate for double-sided coating. The problems that it tries to solve are as follows. That is, the operation surface at the lower end of the conventional paste shielding plate is flat, and when the paste is dispensed, the lead paste has a predetermined pressure, so the electrode plate is recessed downward, and the distance between the paste blocking plate and the middle of the electrode plate is The amount of intermediate paste becomes relatively large. The raw electrode plate after double-sided coating is thick in the middle and thin at both ends, and after curing, the electrode plate is severely curved, affecting the quality of the electrode plate.

The above-described flexible paste blocking plate such as double-sided coating is provided with a paste blocking plate and a paste blocking plate, and has a paste outlet for electrode paste, and the paste outlet penetrates the paste blocking plate up and down. The working surface at the lower end of the paste-blocking plate has an arc shape protruding outward, and the operating surface having an arc shape protruding outward compensates for the deformation amount of the electrode plate in combination with the electrode plate recessed downward, and the thickness of the electrode plate paste Is basically the same and is characterized by enhancing the quality of the product.

CN 201906687U, which is a utility model patent in China, discloses an eccentricity adjusting device that controls the thickness of the electrode plate with a coating machine. During actual use, the eccentricity adjusting device can detect the thickness of the electrode plate at random. When wave motion occurs, the thickness of the electrode plates passing through the coating machine is matched by making dynamic adjustments without stopping the equipment.

Japanese Unexamined Patent Publication No. 57-21068 discloses a method for producing a positive electrode for a sealed lead-acid battery. That the lead paste density is 3.0 to 3.4 g / cm ³ (usually the lead paste density is 3.7 to 4.1 g / cm ³ ) and the active material, the lead paste is filled in the lattice. Features. The problem to be solved by the method is to increase the porosity of the positive electrode plate by reducing the density of the lead paste of the positive electrode plate and improve the rapid discharge characteristics of the sealed lead-acid battery. However, an aqueous dispersion of polytetrafluoroethylene (PTFE) was added to the lead paste in order to suppress the shortening of the life due to the decrease in the density of the lead paste.

Japanese Patent Publication No. 58-223259 discloses a method for manufacturing a lead-acid battery plate. After filling a band-shaped expanded lattice plate made of lead or a lead alloy with lead paste as an active material, it is pressed and compressed into a cutting part having a certain width at a predetermined interval in the length direction, and the cutting The center of the part is cut to produce a single electrode plate, which is then dried. As shown in FIG. 4 of the document, the electrode plate manufactured by the manufacturing method is thinner at both end portions than the intermediate portion. The problem to be solved by the production method is to overcome the disadvantage that the active material has a weak holding power in the conventional cutting part and the active material is easily dropped.

Japanese Unexamined Patent Publication No. 2007-258088 discloses an electrode plate for a lead storage battery in which an active material is filled in a grid having a current collecting ear on one end side. The lattice body is formed so that its thickness gradually increases from the one end side to the other end side, but the active material layer has a thickness from the one end side to the other end side. It is formed to become thinner gradually. Thereby, the thickness of the electrode plate obtained from the sum of the thickness of the lattice body and the thickness of the active material layer covering the lattice body is basically equal from one end side to the other end side of the lattice body. . The lead-acid battery electrode plate can prevent the active material layer near the ears covering the grid body from being too thin to expose a part of the grid body, and prevent deterioration of battery performance. Can do.

Japanese Unexamined Patent Application Publication No. 2003-86175 discloses a filled electrode plate for a lead storage battery that has no uneven thickness, has no surface irregularities, and has a smooth surface. By filling the substrate with lead paste, which is an active material, and performing the drying process, the packed electrode plate passes between the rollers of the rolling mill to obtain a uniform thickness by pressing the thickness of the packed electrode plate. Thus, the deposits and protrusions on both sides of the filling electrode plate become flat. The filled electrode plate for a lead storage battery can better prevent defects such as a short circuit.

From the above, in the prior art, the surface of the lead-acid battery plate is generally flat and the thickness is uniform, which is advantageous for the performance of the lead-acid battery, and also advantageous for the assembly and charging of the battery. It is considered. In the prior art, a method has been found to some extent in consideration of the design of the electrode plate. For example, as described above, the porosity of the positive electrode plate is increased by reducing the lead paste density of the positive electrode plate. This improves the rapid discharge characteristics of the sealed lead-acid battery. However, reducing the lead paste density leads to a shortened battery life. Alternatively, the thickness of both end portions of the electrode plate is made thinner than that of the intermediate portion, thereby overcoming the disadvantage that the active material holding force at the end portions is weak and the active material easily falls off.

However, if the surface of the electrode plate is flat and the electrode plates have the same thickness, the capacity cannot be continuously increased because more sulfuric acid accumulates and the chemical reaction cannot proceed better, The designed initial capacity may not be reached. In addition, when the surface of the electrode plate is flat and the electrode plates have the same thickness, the distance between the positive electrode plate and the negative electrode plate may be too short, causing a short circuit and affecting the cycle life. If the electrode plate is too flat, the separator and the electrode plate are in close contact with each other, and oxygen generated at the end of charging with the positive electrode plate cannot diffuse into the negative electrode, affecting the oxygen reaction and reducing the charging efficiency. To do.

CN10593430A, a Chinese patent publication, discloses a lead storage battery electrode plate and a method for manufacturing the same. The electrode plate includes two protruding end portions having protrusions and a flat intermediate portion between the both end portions, and the thickness of the end portion is larger than the thickness of the intermediate portion. When the thickness of the intermediate portion is H2, and the difference between the thickness of the end portion and the thickness of the intermediate portion is H1, the value of H1 / H2, which is the ratio of H1 and H2, is 3% to 9%. is there. According to the present invention, the electrode plate is designed so that the protrusion is formed at the end and the protrusion has the protrusion, so that the thickness of the end of the electrode plate is made larger than the thickness of the other part. Yes. Therefore, since the space | interval of a positive electrode plate and a negative electrode plate becomes large suitably, the cycle life, capacity | capacitance, and charging efficiency of the battery were improved.

However, the present invention seeks to provide a lead storage battery in which the life characteristics, charge efficiency characteristics and high rate discharge characteristics of the lead storage battery are improved and the overall performance is greatly improved.

An object of the present invention is to provide a lead storage battery having excellent cycle life, charge efficiency, discharge capacity, and high rate discharge characteristics.

According to the present invention, the above technology is achieved by forming a projection at the end and designing the electrode plate so that the thickness of the end of the electrode plate is larger than the thickness of the other portions and using a high-density separator. To solve specific problems.

That is, the present invention provides the following solutions.

(1) A plurality of cell batteries having an electrode plate group, an electrolytic solution, and a cell battery chamber, wherein the electrode plate group and the electrolyte solution are accommodated in the cell battery chamber, and the electrode plate group includes a plurality of positive electrode plates and A plurality of negative electrode plates are alternately arranged via separators, and the positive electrode plate includes a positive electrode current collector having positive electrode ears and a positive electrode active material layer held by the positive electrode current collector, The negative electrode plate is a lead storage battery comprising a negative electrode current collector having a negative electrode ear and a negative electrode active material layer held by the negative electrode current collector,
The separator is an AGM separator, and the density of the separator in a state where the electrode group and the electrolytic solution are accommodated in the cell battery chamber is in a range of 117 to 129 g / dm ³ , and the positive electrode plate and the negative electrode plate The current collector of at least one of the electrode plates is an extended grating produced by an extended band method, and the electrode plate includes protruding end portions having protrusions and flat intermediate portions between the both end portions, When the thickness of the both end portions is larger than the thickness of the intermediate portion, the thickness of the intermediate portion is H2, and the difference between the thickness of the end portion and the thickness of the intermediate portion is H1, H1 and H2 The ratio value H1 / H2 is 3% to 9%.

(2) In the lead storage battery according to (1), the ratio value H1 / H2 is 4% to 8%.

(3) In the lead-acid battery according to (1), the width of the end portion is 5% to 25% of the entire width of the electrode plate.

(4) In the lead-acid battery according to (3), the width of the end portion is 10% to 20% of the entire width of the electrode plate.

(5) In the lead-acid battery according to (1), the protrusions of both the protruding end portions are formed on the same side of the electrode plate.

(6) In the lead storage battery according to (1), the protrusions of the both projecting end portions are formed on different sides of the electrode plate.

(7) In the lead acid battery according to any one of (1) to (6), the lead paste density, which is the density of the active material layer of the electrode plate, is 4.15 g / cm ³ to 5.0 g / cm. It is ³ , It is characterized by the above-mentioned.

(8) In the lead storage battery according to any one of (1) to (6), the electrode plate is a positive electrode plate.

(9) In the lead-acid battery according to (1), wherein the lead paste density is the density of the active material layer of the positive electrode plate is ^{4.15g / cm 3 ~ 4.45g / cm} 3.

(10) In the lead acid battery according to any one of (1) to (6), the density of the electrolytic solution after the formation of the lead acid battery is 1.33 to 1.35 g / cm ^3. Features.

(11) The lead acid battery according to (1), wherein the electrolytic solution is a sulfuric acid aqueous solution containing sulfuric acid and water.

(12) The lead-acid battery according to (1) or (11), wherein the electrolyte contains a small amount of an additive that can be completely dissolved in the electrolyte.

According to the present invention, the electrode plate is designed so that the thickness of the end portion of the electrode plate is larger than the thickness of the other portions by forming protrusions at the end portions. Thereby, the space | interval of a positive electrode plate and a negative electrode plate becomes large suitably, the possibility of a short circuit occurrence is reduced significantly, and cycle life improves. In addition, more electrolyte solution is accumulated between the positive electrode plate and the negative electrode plate, the chemical reaction proceeds better, the capacity is improved, and oxygen generated at the end of charging in the positive electrode plate can be diffused to the negative electrode in real time. This is advantageous for the reaction and improves the charging efficiency. At the same time, since the distance between the positive electrode plate and the negative electrode plate is not too large, the internal resistance is low. Based on this, by using a high-density separator, it is possible to secure the volume of pores in the separator (that is, the volume that holds the electrolyte) and to use the capillary phenomenon. As a result, the obtained lead storage battery has excellent cycle life, charge / discharge efficiency, discharge capacity, and high-rate discharge characteristics (that is, high-rate discharge capacity).

FIG. 1 schematically shows an electrode plate group using a high-density AGM separator and electrode plates having both protruding end portions in the lead storage battery of the present invention and having both end portions larger in thickness than the intermediate portion. FIG. FIG. 2 is a schematic diagram of Embodiment 1 of the electrode plate for a lead storage battery of the present invention. FIG. 3 is a schematic diagram of Embodiment 2 of the electrode plate for a lead storage battery of the present invention. 4A is a schematic perspective view of the battery electrode plate according to the first embodiment of the present invention, and FIG. 4B is a front view of the battery electrode plate shown in FIG. 4A. c) is a cross-sectional view of the battery electrode plate shown in FIG. FIG. 5 (a) is a process diagram for manufacturing the extended grating and the electrode plate by the extended method, and FIG. 5 (b) is a partially enlarged schematic view of the above process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, for the sake of simplicity, components having substantially the same functions are denoted by the same reference numerals. The present invention is not limited to the following embodiment.

The present invention provides a lead acid battery having a plurality of cell batteries. The lead storage battery includes a plurality of cell batteries having an electrode plate group, an electrolyte solution, and a cell battery chamber, the electrode plate group and the electrolyte solution are accommodated in the cell battery chamber, and the electrode plate group includes a plurality of positive electrodes. The positive electrode plate includes a positive electrode current collector having positive electrode ears, and a positive electrode active material layer held by the positive electrode current collector. And a negative electrode current collector having the negative electrode ear and a negative electrode active material layer held by the negative electrode current collector. The separator is an AGM separator, and the density of the separator in a state where the electrode group and the electrolytic solution are accommodated in the cell battery chamber is in a range of 117 to 129 g / dm ³ , and the positive electrode plate and the negative electrode plate At least one of the electrode plates has the following structure, that is, the current collector of the electrode plate is an extended grating produced by an extended method, and the electrode plate has both protruding end portions having protrusions. And a flat intermediate portion between the both end portions, the thickness of the end portion is larger than the thickness of the intermediate portion, the thickness of the intermediate portion is H2, and the thickness of the end portion and the intermediate portion When the difference from the thickness is H1, the ratio H1 / H2 of H1 and H2 is 3% to 9%. The thickness of the end portion refers to the maximum thickness of the protruding end portion.

In the present invention, the electrode plate is designed so that the thickness of the end portion of the electrode plate is larger than the thickness of the other portions by forming protrusions at the end portions. Thereby, the space | interval of a positive electrode plate and a negative electrode plate becomes large suitably, and the electrode plate for batteries which has the outstanding capacity | capacitance, cycle life, and charging efficiency simultaneously can be provided. Specifically, first, the reaction space can be increased, more sulfuric acid can be accumulated, and the reaction can be performed longer. As a result, the capacity can be improved. Next, both ends of the electrode plate are thick, and the ribs at the grid cutting portions on both ends are far from the surface of the electrode plate, and it is difficult to break the separator and make a short path. At the same time, the strength of both end portions is large, so that there is an action of suppressing the growth of the electrode plate. As a result, cycle life can be improved. In addition, because both ends are thick, a predetermined gap is created between the middle part of the electrode plate and the separator, which is advantageous for oxygen transport during charging, and suppresses reduction in charging efficiency due to simultaneous non-diffusion of oxygen and loss of oxygen. can do. As a result, charging efficiency can be improved. During normal charging of the battery, a part of the electric power is used for the reaction of lead sulfate and the other part is used for the decomposition of water. If oxygen cannot be transported to the negative electrode in real time, deposition tends to occur. As a result, The lead sulfate reaction is inhibited by oxygen deposition. No.2. O Due to the accumulation of oxygen, oxygen cannot diffuse to the negative electrode in real time. Therefore, it leads to the loss of oxygen and loses water. Both of the above two points lower the charging efficiency. The charging efficiency here refers to the difficulty of the lead sulfate reaction and the efficiency of oxygen circulation.

On the other hand, it is considered that the lead storage battery is required to have a small interval between the positive electrode plate and the negative electrode plate adjacent to each other in order to give the lead storage battery excellent high rate discharge characteristics. However, if it is too small, precipitates such as dendritic crystals are likely to reach the counter electrode, resulting in a short circuit. In addition, the separator disposed between the positive electrode plate and the negative electrode plate generates a compressive action, which also affects the distribution of the electrolytic solution in the separator. Specifically, if the distance between the positive electrode plate and the negative electrode plate is too small, the separator layer is excessively compressed and only a small amount of the electrolyte can be maintained, so that the discharge capacity is reduced. When the gap between the positive electrode plate and the negative electrode plate is increased, the separator disposed between the positive electrode plate and the negative electrode plate is recessed, the contact reaction area is reduced, the discharge capacity is reduced, and the high rate discharge characteristics are reduced.

However, as described above, at least one of the positive electrode plate and the negative electrode plate in the lead storage battery of the present invention has both projecting end portions, and the thickness of the both end portions is an intermediate portion. Since it is larger than the thickness, the interval between the positive electrode plate and the negative electrode plate is increased, and as a result, the cycle life and the like are improved, but the high-rate discharge capacity of the lead storage battery may be reduced. On the other hand, this inventor discovered that the high-rate discharge characteristic which was excellent in the lead storage battery can be given by arrange | positioning a separator between a positive electrode plate and a negative electrode plate by higher density. Therefore, in the present invention, an AGM separator is used, and the density of the separator is set in a range of 117 to 129 g / dm ³ . It is clear that the density range is higher than the density of conventional lead-acid battery separators. Furthermore, in the present invention, the upper limit of the density of the separator is set to 129 g / dm ^{3 because} if the separator density is further increased, the cycle of the electrolyte in the separator may be affected. It also affects the lifespan.

The density of the separator in the present invention is that which is compressed to a high density of 117 to 129 g / dm ³ when the separator and the electrode plate are pressed to form the electrode plate group. It is determined according to the pressure received in the plate group. However, the density of the separator basically does not change before and after the formation of the battery. In the present invention, the density of the separator refers to the density after chemical conversion.

The material of the glass fiber separator used by the AGM separator is not particularly limited, but a known or commercially available AGM separator for a lead storage battery may be used as long as it meets the requirements of the present invention.

Based on the setting of the structure and composition of the counter electrode plate and the separator, the present invention may use a low density electrolytic solution, and the density of the electrolytic solution at the time of liquid injection is 1.24 to 1.26 g / cm ^3. The density of the electrolytic solution after the formation of the lead storage battery is preferably 1.33 to 1.35 g / cm ³ . In the present invention, the lead-acid battery can be restored to the density of the electrolyte after the formation of the lead-acid battery after the lead-acid battery is fully charged after a certain period of use. Unless otherwise explained, the density of the electrolytic solution refers to the density of the electrolytic solution after the formation of the lead storage battery. The electrolytic solution is preferably an aqueous sulfuric acid solution containing sulfuric acid and water. A small amount of an additive that can be completely dissolved in the electrolytic solution, such as silicon dioxide, sodium tetraborate, and sodium sulfate, may be added to the electrolytic solution. The content of the additive in the electrolytic solution is, for example, 0.2 to 1.0 wt%.

In a lead-acid battery, when the specific gravity of the sulfuric acid aqueous solution as the electrolytic solution increases, a chemical reaction between sulfuric acid and lead becomes active, and lead does not easily precipitate, so that the capacity of the battery is improved. On the other hand, if the specific gravity of the sulfuric acid aqueous solution as the electrolytic solution is increased, the viscosity of the sulfuric acid is too large, which affects the cycle of the electrolytic solution in the separator, and the sulfuric acid adhering to the separator also flows downward or precipitates downward. Becomes easier to separate layers. As a result, the cycle life of the battery is affected.

In the present invention, as a result of using the separator and the electrolytic solution having the above density, it has been found that the cycle life, charge / discharge efficiency, discharge capacity and high rate discharge capacity of the battery are all improved.

The lead storage battery of the present invention is preferably a valve-controlled lead storage battery.

FIG. 1 schematically shows an electrode plate group using a high-density AGM separator and electrode plates having both protruding end portions in the lead storage battery of the present invention and having both end portions larger in thickness than the intermediate portion. FIG. Although FIG. 1 shows a negative electrode plate having protrusions at both ends, it is preferable that protrusions are actually formed at both ends of the positive electrode plate in the present invention, as will be described later. However, in the electrode group shown in FIG. 1, since the positive electrode plate is covered with the separator and is difficult to see, it is schematically shown by the negative electrode plate exposed to the outside. The state in which the protrusions are formed on both ends of the negative electrode plate is the same as the state in which the protrusions are formed on both ends of the positive electrode plate.

FIG. 2 is a schematic diagram of Embodiment 1 of the electrode plate for a lead storage battery of the present invention. As shown in FIG. 2, the thickness of the intermediate portion of the electrode plate is H2, the difference between the thickness of the end portion of the electrode plate and the thickness of the intermediate portion is H1, and the width of the end portion of the electrode plate is H3. And the total width of the electrode plate is H4. In FIG. 2, it is preferable that the protrusions of the both protruding end portions are formed on the same side of the electrode plate and are cut by a hobbing method in a cutting process described later.

FIG. 3 is a schematic diagram of Embodiment 2 of the electrode plate for a lead storage battery of the present invention. As shown in FIG. 3, the shape of the protrusions of each of the two protruding ends is different from that shown in FIG. 1, and the protrusion of each of the protruding ends is different from that of the electrode plate. It is preferable to form by cutting by the press method formed in the side and used for the cutting process mentioned later.

4A is a schematic perspective view of the battery electrode plate according to the first embodiment of the present invention, and FIG. 4B is a front view of the battery electrode plate shown in FIG. 4A. c) is a cross-sectional view of the battery electrode plate shown in FIG.

As shown in FIGS. 4 (a), (b), and (c), the electrode plate is composed of both protruding end portions having protrusions and flat intermediate portions between the both end portions. The thickness is greater than the thickness of the intermediate portion. The protrusions of both protruding ends may be formed by a current collector and / or an active material layer held by the current collector, but considering the simplification of the process and the reduction of cost, The protrusion is preferably formed only by the active material layer.

The thickness of the protrusion is the thickness difference H1, and if the H1 does not fall within a predetermined range, an appropriate gap cannot be formed between the separator and the electrode plate. Therefore, charging efficiency can be increased, short circuit can be prevented, and cycle life and capacity can be increased. However, if H1 is too large, the active materials at both ends protrude excessively, and on the contrary, the risk of a short circuit increases. At the same time, the gap between the electrode plates is too large, accelerating the loss of water in the battery, resulting in an adverse effect. On the other hand, if H1 is too small, the difference in thickness between the both end portions and the intermediate portion is not clear, and the charging efficiency cannot be improved efficiently. Further, the effect of suppressing the growth of the electrode plate is not clear. Therefore, considering the above two points, the ratio value H1 / H2 of H1 and H2 is 3% to 9%. Further, when the ratio value H1 / H2 is 3% to 9%, the capacity of the battery is about 10% to 20% higher than when the ratio value H1 / H2 is 0. From the viewpoint of better effects, the ratio value H1 / H2 is more preferably 4% to 8%.

Note that the shape of the protrusion is not particularly limited, but may be a dome shape, a mountain peak shape, or the like as long as it can form a protruding end. The thickness of the protrusion refers to the maximum thickness at the apex of the protrusion.

The width of the protrusion is the width H3 of the end of the electrode plate. If the H3 is too large, production becomes difficult, and the gap between the separator and the electrode plate is too large. Therefore, the expansion of the active material in the electrode plate group cannot be effectively prevented, and the active material cannot be prevented from falling off. Therefore, the cycle life of the battery is deteriorated. On the other hand, if the H3 is too small, the stress at both ends of the electrode plate is too low to suppress the growth of the electrode plate effectively, resulting in unstable battery capacity and poor cycle life. Therefore, considering the above two points, the ratio value H3 / H4 is preferably 5% to 25%, and more preferably 10% to 20%.

The electrode plate may be a positive electrode plate or a negative electrode plate, but is preferably a positive electrode plate. This is because in a lead-acid battery, the positive electrode generates gas, the grid of the positive electrode plate is likely to grow, and short paths are likely to occur. Further, since the capacity of the battery is controlled by the positive electrode, the effect can be further improved when the protrusion is formed on the positive electrode plate as compared with the negative electrode plate.

The projections of each of the two projecting ends may be formed on the same side of the electrode plate or may be formed on different sides, but the former is preferable. This is because the gap formed when both protrusions are formed on the same side of the electrode plate is larger than the gap generated when both protrusions are formed on different sides of the electrode plate, and more sulfuric acid is accumulated. Battery capacity can be increased. In addition, the electrode plate in this state can increase the charging efficiency of the battery, and has a remarkable suppression effect on the early expiration of the battery life. Therefore, the performance and effect of the obtained electrode plate group and the battery using the electrode plate group are further improved.

The protrusion can be formed by designing the process conditions of the method for manufacturing the electrode plate, and can also be formed by designing the configuration of the active material layer.

FIG. 5 (a) and FIG. 5 (b) show main steps in the electrode plate manufacturing method. (1) Using a reciprocating press mold, pressing is repeatedly performed on the lead strip 27 formed of lead or a lead alloy to form a plurality of slits along the length direction of the lead strip 27, and the slits Expanding in a direction perpendicular to the surface of the lead strip, and an expanding process for forming a grid-like sheet having a mesh 25 in which a plurality of grid lines intersect, and (2) a pair of rollers of the shaping mold A shaping step of shaping the lattice sheet to obtain an expanded lattice, and (3) a lead paste for forming a lead plate by filling the expanded lattice with a lead paste 24a as an active material along its length direction. An unformed electrode plate 2a is obtained by including a filling step and (4) a cutting step of cutting the expanded lattice filled with the lead paste 24a into a positive electrode plate having the polar ears 9.

Thereafter, the unformed electrode plate 2a is cured, dried and formed to obtain the electrode plate. Chemical conversion may be performed after the electrode plate group is prepared with the unformed positive electrode plate and the negative electrode plate and attached to the battery case of the lead storage battery, or may be performed before the electrode plate group is manufactured, but the former is preferable. .

Note that the above “thickness” refers to the thickness of each part when the battery product is not used after being manufactured.

The projections of each of the two projecting ends according to the present invention are formed simultaneously with the cutting step, that is, may be formed by designing the process conditions of the cutting step. Specifically, the protrusion may be formed by cutting with a hobbing method in the cutting step, or may be formed by cutting with a press method in the cutting step. The specific process and advantages and disadvantages of forming the protrusions by the hobbing method or the pressing method are exactly the same as those described in CN10593430A, which is a Chinese patent application, so refer to the related contents of the document. .

In the present invention, the hobbing method of the hobbing method and the press method is more preferable.

In the present invention, by increasing the strength of the active material at both ends, it is possible to realize the retention of the protrusions formed at both ends of the electrode plate when the electrode plate is cut. That is, it can be realized by increasing the density of the active material. Thus, after cutting an electrode plate, the thick state of both ends can be maintained. From this viewpoint, it is preferable that lead paste density is the density of the active material layer is ^{4.15g / cm 3 ~ 5.0g / cm} 3, 4.25g / cm 3 ~ 4.8g / cm 3 It is more preferable that The lead paste density in the above range is higher than that of normal lead paste. However, the composition of the lead paste for each of the positive electrode plate and the negative electrode plate is different, and the density of the lead paste for forming the protrusions is also different. That is, since the composition of the lead paste of the positive electrode plate and that of the negative electrode plate are different, even if both lead pastes have the same density, the protrusions are somewhat different after being cut by the same cutting method. Moreover, the lead paste of a negative electrode plate needs to change the ratio of the composition component largely according to the characteristic actually requested | required. Therefore, even if the density of the lead paste is the same, the protrusions differ to some extent if the proportions of the composition components are different. Therefore, it is preferable that the electrode plate is a positive electrode plate, preferably of lead paste density of the positive electrode plate is ^{4.15g / cm 3 ~ 4.45g / cm} 3, 4.25g / cm 3 ~ 4. More preferably, it is 35 g / cm ³ .

However, the shape, size and height of the protrusion can be controlled by adjusting the cutting process and blade angle of the cutting cutter under the same lead paste density. Reference is made to a certain CN102593430A.

In the lead storage battery of the present invention, other than the structure and composition of the above members, the structure and composition of other members adopt those of the prior art and are not particularly limited.

For example, the lead storage battery can be assembled by the following method. A plurality of the positive plates and the negative plates are alternately overlapped with each other through the separator structure to obtain an electrode plate group. Then, a positive electrode bus is obtained by welding or casting welding the positive electrode ears of the same polarity in a single electrode plate group using a metal plate such as lead, aluminum or copper. On the other hand, a negative electrode bus is obtained by welding or casting welding the negative electrode ears of the same polarity in a single electrode plate group using a metal plate such as lead, aluminum or copper. Each electrode plate group is accommodated in a plurality of cell battery chambers partitioned by partition walls in the battery case. Using a metal plate such as lead, aluminum or copper, weld the negative electrode bus of the electrode plate group and the positive electrode bus of the electrode plate group of the adjacent cell battery, and then use a metal plate such as lead, aluminum or copper material Then, the negative electrode bus of the electrode plate group of the adjacent cell batteries or the positive electrode bus of the electrode plate group of the next adjacent cell battery is welded. In this way, each electrode plate group is connected in series. That is, by connecting a plurality of cell batteries in series, the positive electrode bus and the negative electrode bus at both ends finally become a positive electrode end and a negative electrode end, respectively. The positive terminal is connected to a positive terminal, and the negative terminal is connected to a negative terminal.

Thereafter, the battery cover is attached to the opening of the battery case. Then, electrolyte solution is inject | poured into each cell battery from the liquid injection port provided in the battery cover, and it forms in a battery case. The density of the electrolytic solution at the time of liquid injection is preferably 1.24 to 1.26 g / cm ³ , and the density of the electrolytic solution after the formation of the lead storage battery is 1.33 to 1.35 g / cm ^3. Is preferred. The electrolyte solution may contain an additive such as silicon dioxide. After the formation, a lead storage battery is obtained by fixing the gas generated in the battery and a valve for discharging the pressure to the liquid inlet.

Hereinafter, the present invention will be described in detail based on examples, but these examples are merely illustrative of the present invention and do not limit the present invention.

(Example C)
(1) Manufacture of positive electrode plate By mixing lead powder (mixture of lead and lead oxide), water, and dilute sulfuric acid as raw materials at a specific gravity ratio of about 100: 12: 14, A positive lead paste is obtained.

Meanwhile, the Pb alloy lead band containing about 0.07 mass% Ca and about 1.3 mass% Sn obtained by pouring is extruded so as to have a thickness of 1.3 mm. As shown in FIG. 5A and FIG. 5B, the expanding process is performed, the press is repeatedly performed on the lead band 27 using a reciprocating press mold, and the length of the lead band 27 is increased. A plurality of slits are formed, and the slits are widened in a direction perpendicular to the surface of the lead strip, thereby forming a lattice-like sheet having a mesh 25 in which a plurality of lattice lines intersect. Thereafter, the lattice sheet is shaped using a pair of rollers of a shaping mold to obtain an expanded lattice. Thereafter, the expanded lattice 25 is filled with a lead paste 24a as an active material along the length direction to form the lead plate 2. Thereafter, the lead plate 2 is cut by a hobbing method so that the positive electrode plate having the positive electrode ears 9 is formed, and protrusions are formed at both ends on the same side of the positive electrode plate. The positive electrode plate thus cut is cured, dried, and formed to obtain a positive electrode plate that holds the positive electrode active material with a positive electrode plate lattice. The chemical conversion may be performed before assembling the electrode plate group, or may be performed after the electrode plate group is assembled and attached to the battery case of the lead storage battery.

For the parameters of each component of the obtained positive electrode plate, refer to values shown in Table 1 described later. The thickness ratio value H1 / H2 obtained is 3%, the width ratio value H3 / H4 is 15%, and the density of the obtained lead paste is 4.3 g / cm ³ . .

(2) Manufacture of Negative Electrode Plate A positive electrode lead paste as a positive electrode active material is obtained by mixing lead powder as a raw material, water, and dilute sulfuric acid at a specific gravity ratio of about 100: 10: 4.

A Pb alloy raw material containing about 0.07% by mass of Ca and about 0.25% by mass of Sn. Make it. Fill the negative grid of the negative plate with negative lead paste. Thereafter, the expanded lattice (lead plate) filled with the above-mentioned lead paste is cut by a hobbing method so as to be a negative electrode plate having negative electrode ears, thereby obtaining an unformed negative electrode plate. The unformed negative electrode plate is cured, dried and formed to obtain a negative electrode plate in which the negative electrode active material is held by the negative electrode plate lattice. The chemical conversion may be performed before assembling the electrode plate group, or may be performed after the electrode plate group is assembled and attached to the battery case of the lead storage battery.

For the parameters of each component of the obtained negative electrode plate, refer to values shown in Table 1 described later. Since the surface of the obtained negative electrode plate is flat, the thickness is uniform, and no protrusion is formed at the end of the negative electrode plate, the ratio H1 / H2 of the thickness of the end is 0 and the width The ratio value H3 / H4 is zero. The lead paste density of the obtained negative electrode plate is 4.8 g / cm ³ .

(3) Manufacture of lead acid battery A plurality of said positive electrode plates and a plurality of said negative electrode plates overlap each other through AGM separators each having a density of 123 g / dm ³ to obtain an electrode plate group. The positive electrode ears of the same polarity in the obtained single electrode plate group are welded to obtain a positive electrode bus. On the other hand, a negative electrode ear with the same polarity is welded to obtain a bath. The six electrode plate groups are respectively accommodated in six cell battery chambers partitioned by partition walls in the battery case. By welding the negative electrode bus of the electrode plate group and the adjacent electrode plate group positive electrode bus, two adjacent electrode plate groups are connected in series. Each electrode plate group is connected in series, that is, each cell battery is connected in series.

In the plurality of series-connected electrode plate groups, one positive electrode bus of the two electrode plate groups positioned at both ends is connected to the positive electrode terminal, and the other negative electrode bus is connected to the negative electrode terminal. Thereafter, the battery cover is attached to the opening of the battery case. Thereafter, sulfuric acid having a concentration of 1.242 g / cm ³ is injected as an electrolytic solution into each cell battery from a liquid inlet provided in the battery lid, and chemical conversion is performed in the battery case. After the chemical conversion, the density of the electrolytic solution is 1.34 g / cm ³ . After the formation, a lead storage battery is obtained by fixing the gas generated in the battery and a valve for discharging the pressure to the liquid inlet. The battery has a capacity of 100 Ah and a rated voltage of 12V.

(4) Performance evaluation of lead acid battery (A) The cycle life characteristic of the obtained lead acid battery was measured, and the obtained result is shown in Table 1 described later.

Measure method of cycle life is as follows.

After measuring the voltage, internal resistance, and weight of a battery that is new within 30 days after fabrication, the battery is fully charged after 25 A discharge to 10.5 V at an environmental temperature of 25 ± 2 ° C. . The charging is performed at a constant voltage of 14.7 V, and the maximum charging current is 40 A or less. After completing such a charging step, the charging step is defined as a first cycle. The discharge and charge are repeated again under the above conditions, and the test is terminated when the discharge capacity of the battery reaches 50% of the discharge capacity of the first cycle. The number of charge / discharge cycles performed is calculated, and the number of cycles is defined as the cycle life.

(B) The capacity (reaction effect of the electrolytic solution) of the obtained lead storage battery was measured, and the obtained results are shown in Table 1 described later.

The electrolyte reaction effect is reflected in the discharge capacity of the battery, and the measurement of the discharge capacity of the battery indicates whether the electrolyte reaction effect is good or bad. The method for measuring the capacity of the battery is as follows.

After measuring the voltage, internal resistance, and weight of a new battery within 30 days of fabrication, the environmental temperature is 25 ± 2 ° C., and after discharging 25 A to 10.5 V, the discharge time (unit is hours) And written in h), and the battery capacity is calculated.

(C) The charging efficiency (charging time) of the obtained lead storage battery was measured, and the obtained results are shown in Table 1 described later.

The method for measuring the charging efficiency (charging time) is as follows.

Charge at a constant voltage of 13.7V at 25 ° C. When the charging current is equal to or less than 0.003 times the rated capacity, it is determined that the battery is fully charged and the charging is terminated. The time from the start of charging to the end of charging is defined as the charging time (the unit is time, denoted by h). In general, the shorter the charging time, the better the charging efficiency.

(D) The high-rate discharge characteristics of the obtained lead storage battery were measured, and the obtained results are shown in Table 1 described later.

The high rate discharge characteristic is the high rate discharge capacity. The method for measuring the high rate discharge capacity is as follows.

After measuring the voltage, internal resistance, and weight of a new battery within 30 days of fabrication, the environmental temperature is 25 ± 2 ° C., and after the discharge of 300 A (3 CA) to 9.6 V, the discharge time ( The unit is time (denoted by h)), and the high rate discharge capacity of the battery is calculated.

(Examples D to I)
In Examples D to I, except for the ratio H1 / H2 of the ratio of the thickness of the protrusions to a value in the range of 4% to 9%, the electrode plate group and lead under the same installation conditions as Example C A storage battery was produced.

(Comparative Example A)
In Comparative Example A, the lead paste density of the positive electrode plate was 4.2 g / cm ^3, and neither of the protrusions was formed on the positive electrode plate and the negative electrode plate. That is, the ratio values H1 / H2 and H3 / H4 are both zero. Other than that, an electrode plate group and a lead storage battery were produced by the same installation and process method as in Example C.

In Comparative Example A, the lead paste density of the positive electrode plate was set lower than 4.3 g / cm ^{3 of} Example C because no protrusion was formed. However, even if the lead paste density of the positive electrode plate is 4.3 g / cm ^{3 due} to a change in the cutting process, it is possible to realize that no protrusion is formed. However, in this case, productivity is lowered.

(Comparative Examples B and J)
In Comparative Examples B and J, an electrode plate group and a lead storage battery were produced under the same installation conditions as in Example C except that the thickness ratio values H1 / H2 of the protrusions were 1% and 10%, respectively. .

As shown in Table 1, from the results obtained in Examples C to I, when the value H1 / H2 of the thickness ratio of the protrusions is in the range of 3% to 9%, the obtained lead storage battery is It can be seen that it has excellent cycle life, charge / discharge efficiency, discharge capacity and high rate discharge capacity at the same time.

However, from the results obtained in Comparative Examples A, B and J, when the ratio H1 / H2 of the thickness ratio of the protrusion is lower than 3% or exceeds 9%, excellent cycle life, charge / discharge Efficiency, discharge capacity and high rate discharge capacity cannot be effectively realized simultaneously. The reason is considered as follows. When the ratio H1 / H2 of the thickness ratio of the protrusion is lower than 3%, the distance between the positive electrode plate and the negative electrode plate is small, and the positive electrode plate and the negative electrode plate are too close to each other. May occur. A short circuit occurs, oxygen is hardly absorbed by the negative electrode, and the electrolyte solution between the positive electrode plate and the negative electrode plate is insufficient. On the other hand, when the ratio H1 / H2 of the thickness ratio of the protrusions is higher than 10%, the distance between the positive electrode plate and the negative electrode plate is too large, that is, the distance between the positive electrode plate and the negative electrode plate is too large, As a result of the active material protruding too much, at least one of the following problems may occur. A short circuit occurs, the amount of moisture lost in the battery increases, and the resistance inside the electrolyte increases.

(Examples L to O)
In Examples L to O, an electrode plate group and a lead storage battery were produced under the same installation conditions as Example F, except that the density of the AGM separator was changed from 117 to 129 g / dm ³ .

(Comparative Examples K, P)
Comparative Example K, in P, except that the density of the AGM separators respectively 115 g / dm ³ and 131 g / dm ^3, others, to prepare a plate group and lead-acid battery at the installation conditions as in Example F.

As shown in Table 1, from the results obtained in Examples L to O, when the density of the AGM separator is in the range of 117 to 129 g / dm ³ , the obtained lead storage battery has excellent cycle life and charge. It can be seen that the discharge efficiency, the discharge capacity, and the high rate discharge capacity are simultaneously provided.

However, Comparative Example K, the results obtained with P, the density of the AGM separator is lower than 117 g / dm ^3, or if it exceeds 129 g / dm ^3, excellent cycle life, charge and discharge efficiency, discharge capacity and It can be seen that a high rate discharge capacity cannot be realized simultaneously. The reason is considered as follows. When the density of the AGM separator is lower than 117 g / dm ³ , the pores in the separator are too coarse and the capillary phenomenon does not work. On the other hand, when the density of the AGM separator exceeds 129 g / dm ³ , there are too few pores in the separator, the electrolyte solution participating in the reaction is insufficient, and the reaction is lowered.

(Examples R to U)
In Examples R to U, the density of the electrolytic solution (the value after the formation of the lead storage battery) was changed from 1.33 to 1.35 g / cm ^3. A plate group and a lead-acid battery were produced.

(Comparative Examples Q and V)
Comparative Example Q, the V, except that the density of the electrolyte solution (the value after conversion of the lead-acid battery), respectively 1.32 g / cm ³ and 1.36 g / cm ^3, and other installation in the same manner as in Example F An electrode plate group and a lead storage battery were produced under the conditions.

As shown in Table 1, from the results obtained in Examples R to U, the density of the electrolytic solution (value after the formation of the lead storage battery) is in the range of 1.33 to 1.35 g / cm ^3. It can be seen that the obtained lead storage battery has excellent cycle life, charge / discharge efficiency, discharge capacity and high rate discharge capacity at the same time.

However, from the results obtained in Comparative Examples Q and V, the density of the electrolytic solution (value after the formation of the lead storage battery) was lower than 1.33 g / cm ³ or exceeded 1.35 g / cm ³ . In this case, it is understood that excellent cycle life, charge / discharge efficiency, discharge capacity, and high rate discharge capacity cannot be effectively realized simultaneously. The reason is considered as follows. When the density of the electrolytic solution (the value after the formation of the lead storage battery) is lower than 1.33 g / cm ³ , the reaction is lowered because the sulfate participating in the reaction is insufficient. In addition, the electrolyte is close to neutral during discharging, and dendritic crystal growth is likely to occur during charging. On the other hand, when the density of the electrolytic solution (the value after the formation of the lead storage battery) exceeds 1.35 g / cm ³ , the lattice is easily corroded and the ion migration resistance is increased.

(Comparative Example W)
In Comparative Example W, the density of the AGM separator was 114 g / dm ^3, and the density of the electrolytic solution (value after the formation of the lead storage battery) was 1.31 g / cm ^3. The electrode plate group and the lead storage battery were produced under the installation conditions of

In Comparative Example W, the density of the AGM separator and the density of the electrolytic solution are not within the scope of the present invention. This is an example corresponding to the above-described technique in CN10259430A of the Chinese patent application which is the prior art of the present invention.

As shown in Table 1, it is clear that the overall performance of the battery of Comparative Example W is different from that of the present invention compared to Example F and the like, and excellent cycle life, charge / discharge efficiency, discharge capacity, and high rate discharge capacity. Cannot be realized at the same time.

(Example X)
In Example X, protrusions are formed at both ends of the negative electrode plate, the thickness ratio value H1 / H2 of the protrusions is 6%, and the width ratio value H3 / H4 is 15%. The surface of the positive electrode plate is flat, the thickness is uniform, and no protrusion is formed at the end of the positive electrode plate, that is, the value H1 / H2 of the thickness ratio of the end of the positive electrode plate is 0, The width ratio value H3 / H4 is zero. Other than that, the electrode plate group and the lead storage battery were produced under the same installation conditions as in Example F.

As shown in Table 1, as compared with Example F, the cycle life characteristics of the battery in Example X are slightly deteriorated. This is because the negative electrode plate lattice has a lower deformation and growth capability than the positive plate lattice during repeated charge and discharge.

(Example Y)
In Example Y, protrusions are formed at both ends of each of the positive electrode plate and the negative electrode plate, the thickness ratio value H1 / H2 of the protrusions is 6%, and the width ratio value H3 / H4 is 15%. is there. Other than that, the electrode plate group and the lead storage battery were produced under the same installation conditions as in Example F.

As shown in Table 1, compared with Example F, the charge / discharge characteristics (discharge efficiency, discharge capacity, and high rate discharge capacity) of the battery in Example Y are slightly lowered. This is because protrusions are formed at both ends of each of the positive electrode plate and the negative electrode plate, the distance between the positive electrode plate and the negative electrode plate is too large, and the resistance increases.

The present invention provides a lead storage battery having excellent cycle life, charge / discharge efficiency, discharge capacity, and high-rate discharge capacity, and the lead storage battery is not used as a power source for starting a vehicle, an illumination power source, and a standby power source. It is also widely used as a power source, that is, an independent power source for charging and discharging equipment. For example, electric power storage devices such as electric vehicles, electric forklifts, electric buses, electric bicycles, electric motorcycles, electric scooters, small electric mopeds, golf cars, electric locomotives, and solar batteries.

Claims

A plurality of cell batteries having an electrode plate group, an electrolytic solution, and a cell battery chamber, wherein the electrode plate group and the electrolyte solution are accommodated in the cell battery chamber, and the electrode plate group includes a plurality of positive electrode plates and a plurality of negative electrodes. The plates are alternately arranged via separators, and the positive electrode plate includes a positive electrode current collector having a positive electrode ear and a positive electrode active material layer held by the positive electrode current collector, In a lead storage battery comprising a negative electrode current collector having a negative electrode ear and a negative electrode active material layer held by the negative electrode current collector,
The separator is an AGM separator, and the density of the separator in a state where the electrode plate group and the electrolytic solution are accommodated in the cell battery chamber is in a range of 117 to 129 g / dm 3 , and the positive electrode plate and the negative electrode plate The current collector of at least one of the electrode plates is an extended grating produced by an extended band method, and the electrode plate includes protruding end portions having protrusions and flat intermediate portions between the both end portions, When the thickness of the both end portions is larger than the thickness of the intermediate portion, the thickness of the intermediate portion is H2, and the difference between the thickness of the both end portions and the thickness of the intermediate portion is H1, H1 and H2 Lead acid battery characterized in that the ratio value H1 / H2 is between 3% and 9%.
2. The lead acid battery according to claim 1, wherein the ratio value H1 / H2 is 4% to 8%.
2. The lead acid battery according to claim 1, wherein the width of the end portion is 5% to 25% of the entire width of the electrode plate.
4. The lead acid battery according to claim 3, wherein the width of the end portion is 10% to 20% of the entire width of the electrode plate.
2. The lead acid battery according to claim 1, wherein the protrusions of each of the projecting end portions are formed on the same side of the electrode plate.
2. The lead acid battery according to claim 1, wherein the protrusions of each of the projecting end portions are formed on different sides of the electrode plate.
In lead-acid battery according to any one of claims 1 to 6, characterized in that lead paste density is the density of the active material layer of the electrode plate is 4.15g / cm 3 ~ 5.0g / cm 3 Lead storage battery.
The lead acid battery according to any one of claims 1 to 6, wherein the electrode plate is a positive electrode plate.
In lead-acid battery according to claim 1, lead-acid battery, wherein the lead paste density is the density of the active material layer of the positive electrode plate is 4.15g / cm 3 ~ 4.45g / cm 3.
7. The lead acid battery according to claim 1, wherein the density of the electrolytic solution after the formation of the lead acid battery is 1.33 to 1.35 g / cm 3 .
2. The lead acid battery according to claim 1, wherein the electrolyte is an aqueous sulfuric acid solution containing sulfuric acid and water.
12. The lead acid battery according to claim 1 or 11, wherein the electrolyte contains a small amount of an additive that can be completely dissolved in the electrolyte.