JPWO2012132477A1 - Lead-acid battery and electric vehicle - Google Patents

Abstract

An object of the present invention is to provide a lead-acid battery that can perform high-rate discharge and has a long life even in the case of shallow depth of charge (SOC). The present invention is a lead storage battery 1 composed of a plurality of unit cells 12, and the unit cell 12 includes a group of electrode plates 11 in which a plurality of positive electrode plates 2 and a plurality of negative electrode plates 3 are alternately arranged with separators 4 interposed therebetween. And a single cell quality 14 that accommodates the electrode plate group 11 together with the electrolytic solution. In the single cell 12, the plurality of positive electrode plates 2 are connected in parallel by the positive electrode bus bar 6 connected to the ear portion 9, and the plurality of negative electrodes The plate 3 is connected in parallel by the negative electrode bus bar 5 connected to the ear portion 10, and the ratio (K / L) of the ear cross-sectional area (K) of the positive electrode plate 2 to the ear cross-sectional area (L) of the negative electrode plate 3 is 0.6 or more and less than 1.0, and in the adjacent single cell 12, the positive electrode bus bar 6 of one single cell 12 and the negative electrode bus bar 5 of the other single cell are directly connected. .

Description

  The present invention relates to a lead-acid battery and an electric vehicle equipped with the same as a power source for power.

  In addition to being used as a vehicle starting power source and a backup power source, the lead storage battery is widely used as a main power source. In other words, lead-acid batteries are used as power sources for independent charging / discharging devices, as well as power sources for electric vehicles, electric bicycles, electric motorcycles, electric scooters, moped electric motorcycles, golf carts, etc., and also as solar cells. It has been broken. In these applications, the operation of the lead-acid battery is characterized by a large current during startup, a small discharge current during travel, and a long discharge time. At the same time, it is required to reduce the maintenance of the lead acid battery, and in particular, a longer life is required. In terms of extending the life of the battery, the positive electrode active material is suppressed by suppressing the expansion of the positive electrode active material by increasing the pressure applied to the electrode plate group and pressing the positive electrode active material with a separator. But this is a common practice. However, as the size of the battery increases, changing the material to reinforce the battery case or increasing the wall thickness of the battery case may apply an appropriate pressure to the electrode plate group as described above. It was difficult to maintain pressure. Lead acid storage batteries corrode due to oxidation of the positive electrode current collector as the service period becomes longer, so that the cross-sectional area of the positive electrode current collector is reduced and the conductivity of the entire positive electrode plate is lowered. Therefore, the voltage characteristics when the battery discharges at a high rate deteriorates. When such corrosion of the positive electrode current collector further proceeds, the positive electrode current collector itself is eventually broken, so that the capacity of the battery is rapidly reduced and the life is exhausted.

  Various studies are being conducted on the characteristics, such as capacity, charge / discharge characteristics, safety, etc., of lead-acid batteries for electric vehicles and structures corresponding thereto.

  Patent Document 1 discloses a valve-controlled sealed lead-acid battery without a pole, and the lead-acid battery is manufactured by the following method. First, the pole group is composed of positive and negative electrode plates using a separator, filled with molten lead to form a bus bar, and the bus bar is used instead of the intermediate pole column, and the ears of the positive and negative electrode plates in the pole group Are connected to each other to form a single pole group. Next, a plurality of single pole groups are arranged in parallel in the casing of the battery, lead is melted by gas welding, and bus bars respectively connected to the ears of the positive and negative electrode plates are connected to form a single pole group A series connection is formed between the two. Next, the battery is covered and fixed, and then the positive and negative terminals of the battery are pulled out by using copper wires instead of copper terminals at the positive and negative terminals. In this invention, the use of bus bar connection instead of bridge welding or wire connection has fundamentally solved the problem of terminal corrosion due to terminal leakage and shortened battery life. Is significantly reduced, costs are reduced, and production efficiency is improved.

  Patent Document 2 discloses a lid for a lead acid battery corresponding to a bus bar serial connection type structure, and the lid includes a lid body, and a groove for a sealing material is engraved on the inner surface of the lid body. The inner surface of the lid body has a bus bar sealing groove deeper than the sealing material groove, and the sealing material groove and the bus bar sealing groove communicate with each other. The so-called bus bar series connection structure is constructed by directly welding two electrode groups in one firing and sealing the object to be welded inside the battery lid using a heat conductive sealing material. It is. Therefore, the heat generated from the bus bar is rapidly transmitted and released through the heat conductive sealing material. In the present invention, a bus bar communicating with the groove for sealing the inner surface of the lid is provided, and the bus bar can extend directly into the sealing groove, and a bus bar serial connection type structure of the lead acid battery can be realized. The conductive effect of the battery can be greatly improved, the internal space of the battery can be saved, and the energy density of the battery can be improved. Lead-acid batteries can be charged and discharged with a large current, the application fields of lead-acid batteries are expanded, and the development of related industries such as the electric vehicle industry is promoted.

  Patent Document 3 discloses a group of electrode plates in which the width of the leg portion of the negative electrode plate grid is made larger than the width of the leg portion of the positive electrode plate lattice, and the negative electrode plate and the positive electrode plate made of these electrode plate lattices are assembled. Is inserted into a battery case, and a lead storage battery is disclosed in which each leg is attached to a cage that can absorb the elongation of the electrode plate. While using a lead-acid battery, the positive electrode plate tends to stretch, but the elongation cannot be sufficiently absorbed with scissors, causing a short circuit between adjacent negative electrode plates due to bending of the positive electrode plate, etc. There was a problem of causing. By making the cross-sectional area of the legs of the negative electrode plate lattice larger than the cross-sectional area of the legs of the positive electrode plate lattice, the negative electrode absorption effect on the elongation of the positive electrode plate is increased. It can be prevented from occurring. Further, in paragraph 0006 of Patent Document 3, in the design of a lead plate battery grid, the thickness of the negative plate grid is usually required to be thinner than the thickness of the positive plate grid. It is stated that the width of the legs of the grid of the negative electrode plate must be larger than the width of the legs of the grid of the positive plate so that the cross-sectional area is larger than the cross-sectional area of the legs of the positive plate grid. .

  Patent Document 4 discloses a sealed lead-acid battery. The bus bar is formed by welding the ears of the electrode plate, and the bus bar is embedded in the inner lid with an adhesive so that the gap between the bus bar and the gap between the adhesive groove walls of the bus bar and the inner lid are the same size. By doing so, the adhesive is not deposited, so that it does not soak into the isolation wall or overflow to the outside of the battery.

  However, the above document does not disclose or explain about extending the service life of the battery in consideration of overdischarge of the lead-acid battery for electric vehicles. Conventionally, the study on extending the service life of the battery in consideration of overdischarge of the lead-acid battery for electric vehicles has also been insufficient. In general, as the discharge current of the lead-acid battery for electric vehicles is larger or the depth of discharge is deeper, there is a possibility of causing overdischarge and the life of the battery is shortened. This is because overdischarge deepens the corrosion of the electrode plate lattice, creates a high resistance layer at the boundary between the electrode plate lattice and the active material, causes softening and peeling of the positive electrode active material, and rapidly reduces the discharge capacity of the battery, This is because the battery cannot be used early, and the life of the battery is greatly reduced. Since the electric vehicle cannot be charged during traveling, the longer the traveling distance, the deeper the discharge depth. In addition, it is necessary to frequently apply a brake or start with a large current every time the driving signal is reached, and it is still necessary to start with a large current even when the battery capacity is insufficient. At this time, overdischarge is most likely to occur. When a lead storage battery for an electric vehicle is actually used, high-rate discharge is required even when the depth of charge (SOC) is shallow, so it is necessary to solve the problem of extending the life.

Chinese Patent Application No. 101459260 China Utility Model Application Publication No. 201590439 Specification Japanese Utility Model Publication No. 5-45910 Japanese Patent Laid-Open No. 3-81952

  An object of the present invention is to provide a lead-acid battery that can perform high-rate discharge and has a long life even in the case of shallow depth of charge (SOC).

  The lead acid battery according to the present invention is a lead acid battery composed of a plurality of unit cells, and the unit cell includes a group of electrode plates in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately arranged via separators, A single cell chamber containing the plate group together with the electrolyte solution, the positive electrode plate is provided with a positive electrode current collector having ears, and a positive electrode active material held by the positive electrode current collector, the negative electrode plate is A negative electrode current collector having an ear part, and a negative electrode active material held by the negative electrode current collector, in a single cell, a plurality of positive electrode plates are connected in parallel with a positive electrode bus bar connected to the ear part, The plurality of negative electrode plates are connected in parallel by a negative electrode bus bar connected to the ear portion, and the ratio (K / L) of the ear portion cross-sectional area (K) of the positive electrode plate to the ear cross-sectional area (L) of the negative electrode plate is 0 .6 or more and less than 1.0, and in the adjacent single cells, the positive electrode bus bar of one single cell and the other The negative bus bar of the single cells, are directly connected.

  According to the lead storage battery of the present invention, the ratio of the sum of the cross-sectional areas of the plurality of positive electrode plates to the sum of the cross-sectional areas of the plurality of negative electrode plates is preferably 0.5 to 0.8.

  According to the lead storage battery of the present invention, the number of the plurality of positive plates is preferably 3 or more, the number of the plurality of negative plates is preferably 4 or more, and the number of the plurality of positive plates is 4 to 9, The number of negative electrode plates is more preferably 5 to 10.

  According to the lead-acid battery of the present invention, the thickness of the ears of the positive electrode plate is smaller than the thickness of the ears of the negative electrode plate, and / or the total thickness of the ears of the plurality of positive electrode plates It is preferably smaller than the sum of the thicknesses of the ears.

  According to the lead storage battery of the present invention, the width of the ear portion of the positive electrode plate is preferably 5 to 8 mm, and the width of the ear portion of the negative electrode plate is preferably 5 to 7 mm.

  According to the lead storage battery of the present invention, it is preferable to have two or more single cells, and more preferably 4 to 8 or more.

  According to the lead acid battery of the present invention, the positive electrode current collector is preferably an expanded lattice produced by a reciprocating (reciprocating) expanding method. At this time, the expanded lattice has a mesh formed by intersecting a plurality of lattice lines, where the lattice line width is W and the thickness of the lattice is T, a ratio (T / W) representing the degree of bending of the lattice. Is preferably in the range of 1.60 to 1.80. Preferably, the lead paste as the positive electrode active material is filled in the expanded lattice, the thickness of the positive electrode plate filled with the lead paste is P, and the thickness of the lattice is T, the overfill rate of the lead paste is The expressed ratio (P / T) is preferably in the range of 1.14 to 1.30.

  According to the lead storage battery of the present invention, the negative electrode current collector is preferably a grid produced by a casting method.

  The lead storage battery of the present invention is preferably used as a power source for powering an electric vehicle, an electric bicycle, an electric motorcycle, an electric scooter, or a moped electric motorcycle.

  The present invention reduces the current collecting property appropriately by reducing the cross-sectional area of the positive electrode ears, and the bus bars of adjacent single cells are welded directly rather than using pole columns. Therefore, it is possible to eliminate the influence on the current collecting performance by connecting the bus bar using the pole pole. Thereby, high-rate overdischarge can be suppressed, long life can be realized, and the volume of the battery can be reduced. In addition, an expanded lattice produced by an expanding method is adopted as the positive electrode current collector, and the stress generated by the mesh of the lattice can be reduced by controlling the bending degree of the lattice. Furthermore, by collecting the positive electrode active material excessively (overfilling) and controlling the overfilling rate of the lead paste as the positive electrode active material, the current collecting property can be appropriately reduced. Thereby, at the time of high-rate discharge, overdischarge of the positive electrode active material can be suppressed and corrosion due to stress can be prevented, and as a result, the life of the battery can be greatly improved.

It is a partially cutaway perspective view of the lead acid battery of the present invention. (A) is a partially cutaway front view of the positive electrode plate of the lead storage battery of the present invention, and (b) is a side view of the positive electrode plate. (A) is a partially cutaway front view of the negative electrode plate of the lead storage battery of the present invention, and (b) is a side view of the negative electrode plate. (A) is process drawing which showed the process of producing an expanded lattice and an electrode plate by the reciprocating expand method, (b) is the schematic diagram which expanded a part of process. (A) is the front view which showed typically the expanded lattice produced by the reciprocating expansion method, (b) is a side view of the electrode plate which consists of an expanded lattice, (c) is a part of expanded lattice. It is the expanded schematic diagram, (d) is sectional drawing along the AA line of the expanded grating | lattice of (c), (e) is a partial cross section cut | disconnected along the thickness direction of a positive electrode plate. FIG. It is the figure which showed typically the state which connected the some single cell in series. It is the table | surface which showed the evaluation result of the characteristic of the lead acid battery in the Example of this invention.

  Hereinafter, the lead storage battery of the present invention will be described with reference to the drawings. For simplification of description, components having substantially the same function are denoted by the same reference numerals in the drawings. In addition, this invention is not limited to the following embodiment.

  The present invention relates to a lead-acid battery, the lead-acid battery has a plurality of unit cells, and the unit cell includes an electrode plate group, an electrolytic solution, and a single cell chamber, and the electrode plate group is immersed in the electrolyte solution. The electrode plate group is formed by alternately arranging a plurality of positive electrode plates and a plurality of negative electrode plates via separators, each positive electrode plate having a positive electrode current collector having an ear portion Each negative electrode plate includes a negative electrode current collector having an ear portion and a negative electrode active material layer held by the negative electrode current collector. Optimize the layout and electrical connection between individual cells, and optimize the layout of the positive and negative plates, the cross-sectional area of the positive and negative plates, and the relative relationship of thickness. By doing so, it is possible to realize a lead-acid battery that can perform high-rate discharge and has a long life even in a shallow depth of charge (SOC) state.

  The lead-acid battery of the present invention may be an open-type liquid lead-acid battery or a sealed valve-controlled lead-acid battery, but is preferably a sealed valve-controlled lead-acid battery. FIG. 1 is a partially cut perspective view of a lead storage battery of the present invention.

  The lead-acid battery 1 has a plurality of single cells 12 with its casing 19 partitioned into a plurality of single cell chambers 14 by separating walls 13, and the single cell 12 includes an electrode plate group 11 and an electrolyte (not shown). ) And the single cell chamber 14, and the electrode plate group 11 is accommodated in the single cell chamber 14 in a state of being immersed in the electrolytic solution. The electrode plate group 11 is formed by alternately arranging a plurality of positive electrode plates 2 and a plurality of negative electrode plates 3 with separators 4 interposed therebetween. From the viewpoint of charge / discharge efficiency and cost reduction, it is preferable that the outermost side of the electrode plate group is the negative electrode plate, that is, the negative electrode plate is one more than the positive electrode plate. This is because in a secondary battery typified by a lead storage battery, the battery capacity means the electric capacity of the positive electrode, and the discharge reaction of the battery is performed between the positive electrode and the negative electrode facing each other via a separator. Therefore, it is preferable that both surfaces of the positive electrode face the negative electrode.

  The number of positive electrode plates is 3 or more, the number of negative electrode plates is preferably 4 or more, the number of positive electrode plates is 4 to 9, and the number of negative electrode plates is 5 More preferably, the number is ~ 10. In the plurality of single cells, the positive electrode bus bar of the positive electrode plate of each single cell and the negative electrode bus bar of the negative electrode plate are respectively connected to the negative electrode bus bar of the negative electrode plate and the positive electrode bus bar of the positive electrode plate of each single cell adjacent to the single cell. The connection employs non-polar column direct welding to connect a plurality of single cells in series. Specifically, the positive electrode ears 9 of each positive electrode plate 2 are connected in parallel through the positive electrode bus bar 6, while the negative electrode ears 10 of each negative electrode plate 3 are connected in parallel through the negative electrode bus bar 5. Each single cell 12 is directly welded to the negative electrode bus bar 5 of each single cell 12 and the positive electrode bus bar 6 of the single cell 12 adjacent to each other by fusion welding or cast welding using a metal plate 8 of lead, aluminum, copper or the like. 12 is connected in series with adjacent single cells 12, and a plurality of single cells are connected in series. Direct welding between the bus bars may be performed so as to straddle the top portion of the isolation wall 13 or may be performed through a hole of the isolation wall 13.

  The inventor of the present application can stabilize the connection state between the single cells by connecting the single cells in series by directly welding the bus bars having different polarities of the adjacent single cells without using the pole columns, As a result, it has been found that the fluctuation of the current collecting property between single cells becomes very small, and the current and internal resistance become small, which is advantageous for high-rate discharge and can have a long life. Specifically, when bus bars with different polarities of adjacent single cells are connected in series indirectly using a pole pole, the current path is long, the internal resistance is large, and the amount of heat generated increases with the increase in internal resistance. Thus, the temperature and current collection between the single cells greatly fluctuate. On the other hand, in the present invention, the bus bars having different polarities of adjacent single cells are directly welded without using a pole column, and the single cells are connected in series, so the current path is short and the internal resistance is short. It is small and the amount of heat generation decreases as the internal resistance decreases. Thereby, the fluctuation | variation of the temperature and current collection property between single cells becomes small. In the present invention, “adopting non-polar column direct welding” and “direct welding without using a pole column” have the same meaning. That is, when the bus bars having different polarities in the adjacent single cells are directly welded or directly welded without using the pole column between the bus bars having different polarities in the adjacent single cells, lead, aluminum or It means that welding is performed by fusion welding or cast welding using a metal plate such as a copper material.

  The lead storage battery 1 preferably has two or more single cells 12, more preferably 4-8. The positive electrode bus bar on one end side in the casing 19 is connected to the positive electrode terminal 16, while the negative electrode bus bar 5 on the other end side in the casing 19 is connected to the negative electrode terminal 17. The battery lid 15 is attached to the opening of the casing 19. The vent or valve 18 provided in the battery lid 15 is for discharging the gas generated in the battery to the outside of the battery, but hardly emits gas.

  The positive electrode plate 2 includes a positive electrode current collector 21 having a positive electrode ear portion 9 and a positive electrode active material layer 24 held by the positive electrode current collector 21. 2A is a partially cut front view of the positive electrode plate 2 of the lead storage battery of the present invention, and FIG. 2B is a side view of the positive electrode plate 2.

  The material of the positive electrode current collector 21 and the positive electrode bus bar 6 may be, for example, a Pb alloy often used for a positive electrode plate of a lead storage battery containing at least one of Ca and Sn. From the viewpoint of corrosion resistance and mechanical strength, In view of this, a Pb—Sn alloy containing 0.05 to 3.0% by mass of Sn, a Pb—Ca alloy containing 0.01 to 0.10% by mass of Ca, or a Pb—Ca—Sn alloy containing Ca and Sn may be used.

The positive electrode active material layer 24 mainly contains a positive electrode active material (PbO ₂ ), but may contain a small amount of a conductive material (for example, carbon) and an additive in addition to the positive electrode active material.

  The positive electrode current collector 21 is preferably an expanded lattice produced by a reciprocating (reciprocating) expanding method. The positive electrode current collector 21 includes a mesh 25 that holds the positive electrode active material layer 24, a side 23 at the edge of the mesh 25, and a positive electrode ear 9 that is connected to the side 23 on the upper surface thereof.

  The negative electrode plate 3 includes a negative electrode current collector 31 having a negative electrode ear 10 and a negative electrode active material layer 34 held by the negative electrode current collector 31. FIG. 3A is a partially cut front view of the negative electrode plate 3 of the lead storage battery of the present invention, and FIG. 3B is a side view of the negative electrode plate 3. The negative electrode current collector 31 is a lattice produced by a reciprocating expand method or a casting method, a mesh 35 holding the negative electrode active material layer 34, an upper frame 33 at the upper edge of the mesh 35, and a negative electrode connected to the upper frame 33 The ear portion 10 may be provided.

  The negative electrode active material layer 34 contains a negative electrode active material, i.e., lead (e.g., sponge-like, blue-blue pure lead), but in addition to the negative electrode active material, a small amount of an expanding agent (e.g., wood and barium sulfate), a conductive material ( For example, carbon) and additives may be contained.

  The negative electrode current collector 31 and the negative electrode bus bar 5 may be made of a Pb alloy often used for a negative electrode plate of a lead storage battery, and are not particularly limited, but considering the strength of the lattice, Ca, Sn, etc. It is preferable to use a Pb—Ca alloy, a Pb—Sn alloy, a Pb—Ca—Sn alloy, or the like to which an element that does not reduce the hydrogen overvoltage of Pb is added. It is more preferable to use the same Pb alloy as the Pb alloy used for the positive electrode plate 2.

  The separator 4 is a separator often used for lead-acid batteries, and may be any of a plastic separator, a paper separator, a glass separator, and a rubber separator. A glass fiber mat or an ultrafine glass fiber separator (AGM) is preferred. The separator may be formed in a bag shape and may be in close contact with the outside of the positive electrode plate so as to surround the positive electrode plate to prevent the active material from peeling and extruding.

  The positive electrode plate 2 can be manufactured by the following manufacturing method.

  The unformed positive electrode plate is filled with a positive electrode lead paste mixed with lead powder (a mixture of lead and lead oxide), sulfuric acid, water, etc., in a positive electrode plate grid as a positive electrode current collector, and then aged and dried. It was obtained.

  The positive electrode plate lattice is preferably an expanded lattice produced by a reciprocal expanding method. Details of the process will be described later. The main steps at this time are shown in FIGS. 4 (a) and 4 (b). (1) Using a reciprocating (reciprocating) press mold, the lead sheet 27 is repeatedly pressed, A plurality of slits are formed along the length direction of the sheet, and the slits are widened in a direction perpendicular to the surface of the lead sheet to form a lattice sheet having a mesh 25 in which a plurality of lattice lines intersect. Expanding process, (2) shaping process using a pair of shaping mold rollers to shape a grid sheet to obtain an expanded grid, and (3) an expanded grid with a positive electrode along its length. A lead paste filling step of filling the lead paste 24a as an active material, and (4) a cutting step of cutting the expanded lattice filled with the lead paste 24a into a positive electrode plate having the positive electrode ears 9. Through this process, an unformed positive electrode plate 2a is obtained.

  Thereafter, the unformed positive electrode plate 2a is formed to obtain the positive electrode plate 2. Chemical conversion may be performed after constituting the electrode plate group using the unformed positive electrode plate and the negative electrode plate and mounted in the casing of the lead storage battery, or may be performed before configuring the electrode plate group, The former is preferred.

  The negative electrode plate 3 can be manufactured by the following manufacturing method.

  The unformed negative electrode plate is filled with a positive electrode lead paste mixed with lead powder (a mixture of lead and lead oxide), sulfuric acid, water, such as wood and barium sulfate expansion agent, in the negative electrode plate grid as a negative electrode current collector And then aged and dried.

  Thereafter, an unformed negative electrode plate is formed to obtain the negative electrode plate 3, that is, the negative electrode plate 3 composed of the negative electrode active material layer 34 held on the negative electrode plate lattice 31. Chemical conversion may be performed after constituting the electrode plate group using the unformed positive electrode plate and the negative electrode plate and mounted in the casing of the lead storage battery, or may be performed before configuring the electrode plate group, The former is preferred.

  The negative electrode plate grid may be produced by a reciprocating expand method or a casting method. When producing a negative electrode plate grid by the reciprocating expand method, the process employed is the same as the process of the positive electrode plate grid, and the subsequent process of the negative electrode plate is also substantially the same as the process of the positive electrode plate.

  As a result of repeated tests and examinations, the inventor of the present application optimally designed the arrangement of the positive electrode plate and the negative electrode plate, the cross-sectional area of the positive electrode plate and the negative electrode plate, the relative relationship of the thickness, etc. It was discovered that high-rate discharge can be achieved even during this time, which is advantageous for realizing a long life. Details are as follows.

  First, in the present invention, by appropriately making the positive electrode ear cross-sectional area smaller than the negative electrode ear cross-sectional area, the current collecting property is reduced, and overdischarge of the positive electrode active material during high rate discharge can be avoided. For this reason, when the electric capacity is low, a high amount of current is not required, and destruction of the positive electrode active material layer can be prevented. However, the positive electrode ear cross-sectional area cannot be made excessively smaller than the negative electrode ear cross-sectional area. If it is too small, the chemical reaction of the electrode, that is, the chemical conversion, is affected. In addition, if the ratio of the cross-sectional area of the positive electrode plate to the cross-sectional area of the positive electrode plate is too small, the internal resistance of the battery increases, the energy density during high-rate discharge decreases, the output power also decreases, and the single unit The cycle life is shortened because of the large temperature variation between the cells. Therefore, considering the above two points, the ratio of the ear cross-sectional area of the positive electrode plate to the cross-sectional area of the negative electrode plate is preferably 0.6 or more and less than 1.0, and more preferably 0.74 to 0.93. Note that the ratio of the sum of the cross-sectional areas of the plurality of positive electrode plates to the sum of the cross-sectional areas of the plurality of negative electrode plates is preferably 0.5 to 0.8, and more preferably 0.59 to 0.78.

  According to the prior art in this field, it is known that the cross-sectional areas of the ear portion of the positive electrode plate and the ear portion of the negative electrode plate have the same value so that the conductive characteristics of the positive electrode and the negative electrode are matched. This is because the cross-sectional area of the conductive material is proportional to the resistance. However, the present invention broke the conventional practice, and an unexpected effect was obtained. Specifically, in the conventional case, the reaction resistance of the positive electrode plate is reduced and the utilization rate of the positive electrode active material during high-rate discharge is increased, but the deterioration of the positive electrode active material is accelerated. On the other hand, in the present invention, by setting the ratio of the ear cross-sectional area of the positive electrode plate and the negative electrode plate as described above, heat is generated uniformly between the single cells during the high rate discharge, and the temperature between the single cells is increased. Can be reduced, and the cycle life can be extended.

  The ear cross-sectional area is obtained by multiplying the width and thickness of the ear. Specifically, as shown in FIGS. 2A and 2B, when the width of the positive electrode ear is α mm and the thickness of the positive electrode ear is β mm, the cross-sectional area (K) of the positive electrode plate is α × 3 (a) and 3 (b), when the width of the negative electrode ear is γ mm and the thickness of the negative electrode ear is ε mm, the ear cross-sectional area (L) of the negative electrode plate is Therefore, the ear cross-sectional area can be adjusted by adjusting the width and / or thickness of the ear.In the present invention, the thickness of the ear of the positive electrode plate is the negative electrode plate. It is preferable that the total thickness of the ears of the plurality of positive electrode plates is smaller than the total thickness of the ears of the plurality of negative electrode plates. Is preferably 5 to 8 mm, more preferably 5 to 7 mm.

  Next, the present invention selectively adjusts the structure and process of the current collectors of the positive electrode plate and the negative electrode plate, thereby suppressing the current collecting property of the positive electrode and preventing the overdischarge of the positive electrode active material during the high rate discharge. be able to. The positive electrode current collector is preferably an expanded lattice produced by a reciprocating (reciprocating) expanding method using a lead sheet, and the negative electrode current collector is preferably a lattice produced by a casting method. In the present invention, the positive electrode plate is preferably an expanded lattice produced by a reciprocating expand method, and the negative electrode plate is preferably a lattice produced by a casting method. In this case, since the positive electrode expanded lattice does not have a horizontal bone, the positive electrode conductivity is not excessively increased and the current collecting property is relatively lowered. Can be prevented, and the effect of extending the life of the battery can be obtained. On the other hand, the cast lattice of the negative electrode plate has horizontal bones, so that the effect of preventing the negative electrode active material from overflowing and expanding can be exhibited, and an excessive increase in the volume of the battery can also be prevented. Further, in the case where the positive electrode plate and the negative electrode plate are both expanded lattices produced by the reciprocating expand method, the negative electrode expanded lattice also has no lateral bone, so that the current collecting property of the negative electrode is suppressed. On the other hand, since the electroconductivity of a positive electrode is raised relatively, there exists a possibility that the effect of this invention cannot be improved.

  The lead storage battery of the present invention has a remarkable technical effect by designing from the above two points. Even at a shallow depth of charge, high rate discharge can be performed, overdischarge of the positive electrode active material during high rate discharge can be prevented, and a long life can be achieved.

  Hereinafter, the process and control at the time of producing an expanded grating | lattice using a lead sheet by the reciprocating expand method are demonstrated in detail.

  The lead sheet may be a lead alloy foil often used in this field, for example, a Pb alloy foil containing at least one of Ca and Sn. From the viewpoint of corrosion resistance and mechanical strength, it is preferably composed of a Pb—Ca—Sn ternary alloy. When a lead sheet having such an alloy composition is used, the cycle life characteristics of the lead storage battery can be easily improved.

  In the expanding process of the present invention, a reciprocating press mold having a pair of movable mold and fixed mold is used. The movable mold (upper mold) has a plurality of continuous cutter parts, and these cutter parts are arranged in a V shape in the lead sheet conveyance direction (i.e., the length direction). A cutter portion is not provided at a position corresponding to the central portion in the vertical direction. The fixed die (lower die) has a plurality of continuous rib portions, and the rib-like surface of the rib portion corresponds to the position where the upper die cutter portion exists. The fixed mold is fixed using an external device, and the movable mold is controlled to press the lead sheet downward from above. When the cutter part of the movable mold passes through the rib wire between the adjacent rib parts, a plurality of intermittent slits are formed on the lead sheet, and the tip of the cutter part continues to be pressed downward and lead along the rib surface. The slit is widened in a direction perpendicular to the sheet surface. The lead sheet is processed into a lattice-like sheet having a plurality of meshes by repeatedly performing pressing while conveying the lead sheet along the length direction of the lead sheet. Moreover, by adjusting the position of the cutter part in the movable mold, the central part in the width direction of the lead sheet becomes a plain part without a mesh, and the part is formed by the cutting frame described later and the upper frame of the grid and the electrode plate. It becomes the ear.

  Usually, since the lattice-like sheet immediately after the expanding process is largely fluctuated and the shape is irregular, in the next shaping step, the lattice-like sheet is formed by using a pair of shaping mold rollers. It needs to be shaped and an expanded grid is obtained after shaping.

  In a conventional shaping process, it is common to shape a grid sheet using a pair of rolling rollers having a large diameter and mass, and since the pressure applied to the grid sheet is large, the height at the intersection (node) of the grid line Is compressed, the thickness of the entire lattice is reduced, and the degree of bending is reduced. The inventor of the present application, when shaping, if the pressure applied to the lattice sheet is too large, the thickness of the entire lattice is reduced and the strength is increased, but the node location is stressed, and therefore, it is easily corroded, and the battery I discovered that it has a negative effect on lifespan. Therefore, in the present invention, a pair of rolling rollers having a small diameter and mass is used. By controlling the pitch and roller pressure between the pair of rollers and reducing the pressure applied to the node portion, the height of the node portion is hardly compressed, and the post-shaping lattice still has a large degree of bending. At this time, since almost no pressure is applied to the node portion, high strength is maintained at the node portion, the corrosion resistance is excellent, the variation in the size of the lattice is small, and the variation in the thickness of the lattice is reduced accordingly. .

  FIG. 5 is a diagram schematically showing the expanded lattice 7 of the present invention obtained by the above method. As shown in FIG. 5 (a), the expanded lattice 7 has a substantially rhombic mesh formed by a plurality of lattice lines g intersecting, and each mesh i is surrounded by four lattice lines g, and each mesh i They are connected by a node f. The expanded lattice 7 is a plain portion where no mesh is formed at the center in the width direction, and FIG. 5A shows only a part of the expanded lattice 7.

  After expanding the slits cut out from the lead sheet in the expanding process, lattice lines g having a certain width and thickness are formed. The width of the grid line g corresponds to the interval between adjacent slits in the width direction of the lead sheet, and the thickness of the grid line g corresponds to the thickness of the lead sheet. In this specification, “grid line width”, “lattice line thickness”, and “lattice thickness” below have their usual meanings in this field. Specifically, as shown in the schematic diagram of FIG. 5C, the width of the lattice line is W and the thickness of the lattice line is t. Here, in FIG. 5 (c) of the present invention, for convenience, the plane on which the grid lines are located is shown to coincide with the page, but in reality, the plane on which the grid lines g are located is on the page. A predetermined inclination angle is provided. When cutting along the line AA in FIG. 5 (c), as shown in FIG. 5 (d), the grid line having the width W has a bent zigzag shape, and two grid lines g at the node location f. The length of the overlapping portion is twice the width W of the lattice line, and the thickness of the overlapping portion (the thickness of the hatched portion in the figure) is the thickness t of the lattice line. Note that the maximum height of the entire lattice in the thickness direction (that is, the height of the node portion f in the thickness direction) is the thickness T of the lattice. In this specification, the ratio T / W of the thickness T of the grating to the width W of the grating line is defined as the degree of bending of the grating.

  The inventor of the present application controls the bending degree T / W of the lattice within a predetermined range by appropriately adjusting the slit interval in the expanding process and appropriately adjusting the pitch between the rollers and the roller pressure in the shaping process. In this case, in the subsequent filling process, the filling property of the lead paste as the active material becomes good, and not only can the lead paste as the active material be smoothly filled into each mesh of the lattice, but also the lead paste is more than the height of the surface of the lattice. I found that I could fill it high. In this specification, such a phenomenon is simply referred to as “overfilling” of the lead paste. In this way, a large amount of active material can be accommodated in the positive electrode lattice, and a battery having a high capacity can be obtained.

  In the present invention, good lead paste applicability can be expected by appropriately increasing the degree of bending T / W of the expanded lattice. That is, the greater the degree of bending of the grating with respect to the unit area electrode plate, the larger the contact area between the grating and the active material, and the closer the distance between the active material surface and the grating. Therefore, not only can the adhesiveness between the active material and the lattice be improved, but also the distance between each location in the active material layer and the lattice is shortened, and variations in current collection are reduced, so that good high-rate discharge characteristics are obtained. This is because it is considered to be advantageous.

  Normally, the edge of the expanded grid is not supported by the outer frame, so to avoid spilling the active material from the edge of the grid, the amount of active material filled must be limited. If the applied active material layer is too thin, the capacity of the battery is limited, and the current collection of the grid becomes relatively excessive, which tends to cause deterioration of the active material. On the other hand, if the applied active material layer is too thick, the surface of the outer layer of the active material will be too far from the lattice, the adhesiveness with the lattice will be insufficient, and the current collection will be uneven in the active material, Separation is likely to occur at the end of discharge, which causes deterioration of the battery recycling life. Therefore, it is necessary to control the overfilling rate of the lead paste within an appropriate range.

  When the bending degree T / W of the lattice is controlled within an appropriate range, the paste applicability is improved, so the amount of paste applied can be increased, and an appropriate lead paste overfill rate can be easily obtained. . Therefore, the high rate discharge characteristics of the battery can be enhanced. From this viewpoint, the bending degree T / W of the lattice is preferably in the range of 1.60 to 1.80, and more preferably in the range of 1.64 to 1.79. When the bending degree of the lattice is too small, the adhesion of the active material on the surface of the lead paste is poor, and when repeated deep discharge is performed, peeling easily occurs and the cycle life of the battery is shortened. On the other hand, if the degree of bending of the lattice is too large, excess current collection occurs, and on the contrary, the active material deteriorates during overdischarge, leading to a reduction in the cycle life of the battery.

  A grid having a suitable range of bends can be produced using a reciprocating press mold without breaking the grid nodes. As described above, since the reciprocating press process has a feature of hardly compressing the nodes of the lattice, a lattice-like sheet having a high degree of bending can be produced. In the subsequent shaping process, a shaping mold that applies a small pressure to the node portion of the lattice is adopted. Therefore, the expanded lattice obtained after the shaping has a large degree of bending and the node portion hardly receives pressure. Therefore, high strength is maintained and corrosion becomes difficult. This is also an important factor for extending the battery life.

  In the present invention, the magnitude of the degree of bending T / W of the grating is determined by two factors: the thickness T of the grating and the width W of the grating line. The thickness T of the lattice is mainly related to the ratio between the thickness of the lattice sheet before rolling and the thickness before and after the lattice sheet is rolled in the shaping process. It depends on factors such as the size of the grid and the width of the grid lines. Therefore, a desired degree of bending can be obtained by appropriately controlling the process conditions in the expanding process and the shaping process. For example, the size of the mesh formed may be controlled by adjusting the size of the downward stroke of the movable die of the reciprocating press die or the length of the slit in the expanding process, or the fixed die. The interval between the slits on the lead sheet may be adjusted by adjusting the pitch of the rib-shaped surfaces and the distance between the cutter parts of the movable mold. In addition, you may control the ratio of the thickness before and behind rolling of a grid | lattice sheet | seat by adjusting the pitch of a pair of rolling roller which rolls a grid | lattice sheet | seat at a shaping process, the pressing pressure of a roller, etc.

  What is expected in the present invention is to obtain a large lattice curvature. Therefore, it is necessary to set a large gap between slits in the expanding process. However, since the thickness of the lead sheet to be used (that is, the thickness of the grid line) is different, there is a predetermined preferable range for the slit interval (that is, the width of the grid line). Specifically, if the gap between the slits is too large for a given lead sheet thickness (the grid line width is too wide), the thickness of the produced grid is too thick, and the overall mass also increases, It is difficult to increase the capacity of the battery. If the interval between the slits is too small (the width of the grid line is too thin), breakage due to corrosion tends to occur, and the high-rate discharge life characteristics of the battery deteriorate.

  The expanded lattice obtained as described above is used as a positive plate lattice, and then lead paste filling is performed. The expanded lattice is filled with lead paste as a positive electrode active material along the longitudinal direction of the lattice. The thickness of the obtained electrode plate means the total thickness of the electrode plates containing lead paste. As shown in FIG. 5B, the thickness P of the electrode plate is a difference in height in the thickness direction between the upper and lower surfaces of the lead paste filled in the lattice. If the amount of lead paste applied is large, the thickness P of the electrode plate also increases.

  As shown in FIG. 5 (e), in this specification, the ratio (P / T) of the thickness P of the electrode plate to the thickness T of the lattice is defined as the overfilling rate of the lead paste. The starting point of the inventors of the present application is to first produce a lattice having an appropriate bending degree, and then fill the lattice with lead paste at a predetermined overfilling rate to obtain excellent high-rate discharge cycle characteristics. . Therefore, as a result of examining the relationship between the overfilling rate of the lead paste and the cycle characteristics of the high-rate discharge, the inventors of the present application obtained excellent high-rate discharge characteristics when the overfilling rate of the lead paste is within a specific range. I found out that From the standpoint of obtaining excellent high-rate discharge characteristics, the ratio of the plate thickness P to the grid thickness T (P / T) is preferably in the range of 1.14 to 1.30, preferably in the range of 1.16 to 1.26. More preferably.

  From the viewpoint of the effect of improving the high-rate discharge characteristics, the inventors of the present application are effective in controlling the degree of bending of the lattice and the overfilling rate of the lead paste, but first, the degree of bending of the lattice T / W is set within a preferable range. I discovered that I had to ensure that. For example, even if the lead paste overfilling ratio (P / T) is any value within the range of 1.14 to 1.30, the bending degree (T / W) of the lattice is outside the preferred range, ie, 1.60 to 1.80. And the cycle life characteristics of the battery are still insufficient.

  The reason is estimated as follows. That is, when the expanded lattice of the positive electrode satisfies the degree of bending T / W = 1.60 to 1.80, the lead paste is likely to be overfilled, and the current collecting property of the positive electrode lattice with respect to the lead paste is appropriately reduced. As a result, the lead paste is not deteriorated during high-rate discharge, and the battery life is extended. When the bending rate of the lattice is not within the predetermined range, even if the lead paste is in an overfilled state, the adhesiveness with the lattice is insufficient, and the possibility of insufficient or excessive current collection becomes large, The effect of improving the high rate discharge characteristics cannot be obtained.

  The lead acid battery 1 shown in FIG. 1 is assembled by the following method.

  The number of positive electrode plates 2 is N, and the number of negative electrode plates 3 is N + 1. The electrode plates 11 are alternately overlapped with each other via the separators 4. Thereafter, the positive electrode ear 9 having the same polarity in the single electrode plate group 11 is fused or cast-welded using a metal plate such as lead, aluminum, or copper material to obtain the positive electrode bus bar 6. On the other hand, the negative electrode ear 10 having the same polarity in the single electrode plate group 11 is fused or cast-welded using a metal plate such as lead, aluminum or copper to obtain the negative electrode bus bar 5. Each electrode plate group 11 is accommodated in a plurality of unit cell chambers 14 separated by a separation wall 13 in the battery casing 19.

  As shown in FIG. 6, using a metal plate 8 such as lead, aluminum or copper, the negative electrode bus bar 5 of each electrode plate group 11 and the positive electrode bus bar 6 of the electrode plate group 11 of a single unit cell adjacent to each other are directly connected to each other. After welding, the negative electrode bus bar 5 of the electrode plate group 11 of the adjacent single cell is further replaced with the positive electrode bus bar 6 of the electrode plate group 11 of the next adjacent single cell using a metal plate 8 such as lead, aluminum or copper. Weld directly. If the series connection is performed in this way, the electrode plate groups are connected in series. That is, a plurality of single cells are connected in series. Eventually, the positive electrode bus bar and the negative electrode bus bar at both ends become the positive electrode terminal 16 and the negative electrode terminal 17, respectively. Thereafter, the battery lid 15 is attached to the opening of the battery casing 19. Next, an electrolytic solution is injected into each single cell from a liquid injection port provided in the battery lid 15, and chemical conversion is performed in the casing 19. Usually, the electrolytic solution is sulfuric acid having a concentration of 1.1 to 1.4 g / ml, but may contain an additive such as silicon dioxide. After the formation, the lead-acid battery 1 is obtained by fixing a valve 18 for discharging gas and pressure generated inside the battery to the liquid inlet.

  The present invention was implemented by selecting and combining the components in the lead storage battery 1, and the following embodiments were obtained.

(Embodiment 1)
The lead storage battery 1 of Embodiment 1 has a plurality of unit cells 12, each unit cell 12 has an electrode plate group 11, an electrolyte (not shown) and a unit cell chamber 14, and the electrode plate group 11 is an electrolyte. Is stored in the single cell chamber 14, and the electrode plate group 11 is formed by alternately arranging a plurality of positive electrode plates 2 and a plurality of negative electrode plates 3 with separators 4 therebetween. Each of the negative electrode plates includes a negative electrode current collector having an ear part and a negative electrode active material held by the negative electrode current collector, the positive electrode current collector having an ear part and a positive electrode active material layer held by the positive electrode current collector. And a material layer. The feature is that the positive electrode bus bar of the positive electrode plate of the single cell and the negative electrode bus bar of the negative electrode plate are each directly welded to the negative electrode bus bar of the negative electrode plate and the positive electrode bus bar of the positive electrode plate of each single cell adjacent to the single cell. Are connected in series, and the ratio of the cross-sectional area of the positive electrode plate to the cross-sectional area of the negative electrode plate is 0.6 or more and less than 1.0. It is preferable that the ratio of the total cross-sectional area of the plurality of positive electrode plates to the total cross-sectional area of the plurality of negative electrode plates is 0.5 to 0.8. The ratio of the ear cross-sectional area of each positive electrode plate to the ear cross-sectional area of the negative electrode plate is preferably 0.74 to 0.93. The ratio of the sum of the cross-sectional areas of the plurality of positive electrode plates to the sum of the cross-sectional areas of the plurality of negative electrode plates is preferably 0.59 to 0.78. The number of the plurality of positive plates is 3 or more, the number of the plurality of negative plates is preferably 4 or more, the number of the plurality of positive plates is 4 to 9, and the number of the plurality of negative plates is 5 to 10 is more preferable.

(Embodiment 2)
The lead-acid battery 1 of Embodiment 2 is the same as the lead-acid battery 1 of Embodiment 1 except that the thickness of the ears of each positive electrode plate is smaller than the thickness of the ears of the negative electrode plates, or the ears of a plurality of positive electrode plates. The total thickness is smaller than the total thickness of the ears of the plurality of negative electrode plates. The thickness of the ear portion of the positive electrode plate is 1.0 to 2.0 mm, preferably 1.2 to 1.8 mm. The thickness of the ear portion of the negative electrode plate is 1.2 to 2.5 mm, and preferably 1.3 to 2.0 mm.

(Embodiment 3)
The lead storage battery 1 of Embodiment 3 is the lead storage battery 1 of Embodiment 1, wherein the positive electrode current collector is an expanded grid produced by the reciprocating expand method, and the bending degree T / W of the grid is in the range of 1.60 to 1.80. In addition, the negative electrode current collector is a lattice produced by a casting method. In addition, the lead paste overfilling rate P / T in the formula expanding lattice is set to a range of 1.14 to 1.30.

(Embodiment 4)
The lead storage battery 1 of Embodiment 4 is the lead storage battery 1 of Embodiment 2, wherein the positive electrode current collector is an expanded lattice produced by a reciprocating expand method, and the bending degree T / W of the lattice is in the range of 1.60 to 1.80. In addition, the negative electrode current collector is a lattice produced by a casting method. In addition, lead paste overfilling rate P / T in the expanded lattice is set to a range of 1.14 to 1.30.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, these Examples are the preferable illustrations of this invention, and this invention is not limited to these Examples.

(Example 1)
(1) Production of positive electrode plate A lead powder (a mixture of lead dioxide and lead), water and sulfuric acid are kneaded at a mass ratio of about 100: 15: 10 to produce a positive electrode lead paste as a positive electrode active material. Obtained.

  A lead sheet, which is a Pb alloy containing about 0.07 mass% Ca and about 1.3 mass% Sn obtained by a casting method, is pressed to 1.3 mm. As shown in FIGS. 4A and 4B, first, the lead sheet 27 is repeatedly pressed using a reciprocating press die to form a plurality of slits along the length direction of the lead sheet. By expanding the slit in a direction perpendicular to the surface of the lead sheet, a lattice-like sheet having a mesh 25 in which a plurality of lattice lines intersect is formed. Thereafter, the lattice sheet is shaped using a pair of shaping mold rollers to obtain an expanded lattice. Thereafter, the expanded lattice is filled with the lead paste 24a as the positive electrode active material in the mesh 25 along the length direction thereof. Thereafter, the expanded grid filled with the lead paste 24a is cut so as to be a positive electrode plate having the positive electrode ears 9. Next, the positive electrode plate cut in this way is aged and dried to form an unformed positive electrode plate 2a. Thereafter, the unformed positive electrode plate 2a is formed to obtain the positive electrode plate 2 in which the positive electrode active material layer 24 is held by the positive electrode plate lattice 21. Chemical conversion may be performed before the electrode plate group is configured, or may be performed after the electrode plate group is configured and mounted in the lead-acid battery casing.

  The parameters of each component of the positive electrode plate are shown in the table of FIG. In the table, “Exp” is an abbreviation for “expanded lattice”.

(2) Production of Negative Electrode Plate Lead powder, water, and sulfuric acid were kneaded at a mass ratio of about 100: 15: 10 to obtain a negative electrode lead paste as a negative electrode active material. A negative electrode plate grid of a negative electrode current collector was prepared using a Pb alloy containing about 0.07 mass% Ca and about 1.3 mass% Sn by a casting method. An unformed negative electrode plate was obtained by filling a negative electrode plate lattice with lead paste. An unformed negative electrode plate was formed to obtain a positive electrode plate 2 in which the negative electrode active material layer 34 was held by the negative electrode plate lattice 31. Chemical conversion may be performed before the electrode plate group is configured, or may be performed after the electrode plate group is configured and mounted in the lead-acid battery casing.

  The parameters of each component of the negative electrode plate are shown in the table of FIG.

(3) Preparation of lead acid battery The lead acid battery 1 shown in FIG. 1 was obtained by the following method.

  The obtained negative electrode plate 3 and the positive electrode plate 2 were made into four sheets, and each was overlapped alternately via the separator 4, and the electrode group 11 was obtained. Thereafter, the positive electrode ear portion 9 and the negative electrode ear portion 10 having the same polarity in the single electrode plate group 11 were connected to obtain the positive electrode bus bar 6 and the negative electrode bus bar 5, respectively. Each electrode plate group 11 was accommodated in a plurality of single cell chambers 14 separated by a separating wall 13 in the battery casing 19. Two adjacent electrode plate groups 11 were connected in series by directly welding nonpolar columns to the negative electrode bus bar 5 of the electrode plate group 11 and the positive electrode bus bar 6 of the electrode plate group 11 of the adjacent unit cell.

  Of the six electrode plate groups connected in series, the positive electrode bus bar 6 of one electrode plate group and the positive electrode terminal 16 in the two electrode plate groups located at both ends are connected, and the negative electrode bus bar 5 of the other electrode plate group. And the negative electrode terminal 17 were connected. Thereafter, the battery lid 15 was attached to the opening of the battery casing 19. Next, sulfuric acid having a concentration of 1.242 g / ml was injected as an electrolytic solution into each single cell from a liquid injection port provided in the battery lid 15, and chemical conversion was performed in the casing. After the formation, a lead-acid battery 1 was obtained by fixing a valve 18 for discharging gas and pressure generated inside the battery to the liquid inlet.

(4) Evaluation of performance of lead storage battery For each of the obtained lead storage batteries 1, high-rate discharge life characteristics and battery volume were measured.

  The method for measuring the high-rate discharge life characteristics is as follows.

Battery specifications: 12V, 20Ah
Charging condition: 14.7V constant voltage charging, maximum charging time: 16 hours Discharging condition: 30A (1.5C) constant current discharging until the voltage drops to 9.6V
The above charge / discharge cycle is repeated, the test is terminated when the discharge capacity of the battery drops to 80% of the discharge capacity of the first cycle, the number of charge / discharge cycles performed is calculated, and the number of cycles Based on this, the high-rate discharge life characteristics were evaluated.

  The criteria for evaluating the high-rate discharge life characteristics are as follows.

◎: The number of cycles is 500 times or more ○: The number of cycles is 300 times or less than 500 times △: The number of cycles is 200 times or more and less than 300 times
×: The number of cycles is 150 or more and less than 200 times. ××: The number of cycles is 150 or less. The battery volume can be expressed simply by the height of the electrode plate group after bus bar welding. The higher the height, the larger the volume of the finally assembled lead-acid battery. According to the size of the battery actually created, the polarity of the adjacent single cell without using the pole column is compared to the case where the bus bar having the polarity of the adjacent single cell using the pole column is indirectly welded. When directly welding different bus bars, the height of the electrode plate group usually increases in the range of about 10 mm to 60 mm. For this reason, in this invention, the evaluation criteria of a battery volume are shown as follows.

    ○: No pole column is used, and the height of the electrode plate group is low.

    X: The height of the electrode plate group is high using the pole column.

(Example 2)
A lead storage battery 1 was produced in the same manner as in Example 1, except that the cross-sectional area of one positive electrode ear and the total cross-sectional area of each positive electrode ear were changed.

Example 3
A lead storage battery 1 was produced in the same manner as in Example 1 except that the cross-sectional area of one positive electrode ear and the total cross-sectional area of each positive electrode ear were changed.

Example 4
A lead storage battery 1 was produced in the same manner as in Example 1 except that the cross-sectional area of one positive electrode ear and the total cross-sectional area of each positive electrode ear were changed.

(Example 5)
The number of positive plates in a single cell was changed to 6 and the number of negative plates was changed to 7. The cross-sectional area of one positive electrode ear, the total cross-sectional area of each positive electrode ear, and the cross-sectional area of each negative electrode ear A lead storage battery 1 was produced in the same manner as in Example 1 except that the total was changed.

Example 6
The number of positive plates in a single cell is changed to 9 and the number of negative plates is changed to 10. The cross-sectional area of one positive electrode ear, the total cross-sectional area of each positive electrode ear, and the cross-sectional area of each negative electrode ear A lead storage battery 1 was produced in the same manner as in Example 1 except that the total was changed.

(Example 7)
A lead storage battery 1 was prepared in the same manner as in Example 1, except that the negative electrode plate lattice 31 was also prepared by the reciprocating expand method, and the negative electrode plate 3 in which the negative electrode active material layer 34 was held by the negative electrode plate lattice 31 was obtained.

(Example 8)
During the production of the positive electrode plate, the roller pitch and the roller pressure of the pair of rolling rollers were adjusted so that the bending degree T / W of the lattice of the positive electrode plate was 1.64 and the overfill ratio P / T of the lead paste was 1.26. Otherwise, a lead-acid battery was produced in the same manner as in Example 1.

Example 9
During the production of the positive electrode plate, the roller pitch and the roller pressure of the pair of rolling rollers were adjusted so that the lattice bending degree T / W of the positive electrode plate was 1.71 and the overfill ratio P / T of the lead paste was 1.21. Otherwise, a lead-acid battery was produced in the same manner as in Example 1.

Example 10
During the production of the positive electrode plate, the roller pitch and the roller pressure of the pair of rolling rollers were adjusted so that the lattice bending degree T / W of the positive electrode plate was 1.79 and the lead paste overfill rate P / T was 1.16. Otherwise, a lead-acid battery was produced in the same manner as in Example 1.

(Comparative Example 1)
Comparative Example 1 is for comparison with Examples 1-6, and differs from Examples 1-6 in the following two points. That is, (1) As a result of increasing the edge width of the positive electrode plate to 9 mm and increasing the total cross-sectional area of the positive electrode plate, the ratio of the ear cross-sectional area of each positive electrode plate to the cross-sectional area of each negative electrode plate Is 1.11, and the ratio of the sum of the cross-sectional areas of the respective positive electrode plates to the sum of the cross-sectional areas of the respective ear parts is 0.89. (2) The positive electrode bus bar of the electrode plate group is connected to the positive electrode pole column, the negative electrode bus bar is connected to the negative electrode pole column, the negative electrode pole column of each single cell is connected in series to the positive electrode pole column of the adjacent single cell, and the adjacent single cell A series connection of cells was realized. In other words, the positive electrode bus bar of the positive electrode plate and the negative electrode bus bar of the negative electrode plate of each single cell are welded and connected to the negative electrode bus bar of the negative electrode plate of the adjacent single cell and the positive electrode bus bar of the positive electrode plate, respectively. Series connection of adjacent single cells is realized. That is, a plurality of single cells are connected in series by an indirect connection method using a conventional pole pole.

(Comparative Example 2)
Comparative Example 2 is for comparison with Examples 1 to 6, and differs from Examples 1 to 6 in the following points. That is, as a result of increasing the width of the ear part of each positive electrode plate to 9 mm and increasing the sum of the ear cross-sectional area of each positive electrode plate, the ratio of the ear cross-sectional area of each positive electrode plate to the ear cross-sectional area of each negative electrode plate is 1.11, and the ratio of the sum of the ear cross-sectional areas of each positive electrode plate to the sum of the cross-sectional areas of each negative electrode plate is 0.89.

(Comparative Example 3)
Comparative Example 3 is for comparison with Examples 1 to 6, and differs from Examples 1 to 6 in the following points. In other words, the ratio of the ear cross-sectional area of each positive electrode plate to the ear cross-sectional area of each negative electrode plate as a result of reducing the width of the ear cross-sectional area of each positive electrode plate to 4.5 mm and reducing the total cross-sectional area of each positive electrode plate Is 0.56, and the ratio of the total cross-sectional area of each positive electrode plate to the total cross-sectional area of each negative electrode plate is 0.45.

(Comparative Example 4)
Comparative Example 4 is for comparison with Examples 8 to 10, and is different from Examples 8 to 10 in the following points. That is, the positive electrode bus bar of the positive electrode plate and the negative electrode bus bar of the negative electrode plate of each single cell are welded and connected to the negative electrode bus bar of the negative electrode plate of the single cell adjacent to the single cell and the positive electrode bus bar of the positive electrode plate, respectively. In this way, series connection of adjacent single cells is realized. That is, a plurality of single cells are connected in series by an indirect connection method using a conventional pole pole.

  The table of FIG. 7 shows the production conditions of each positive electrode plate and negative electrode plate of each example and each comparative example, each component, and the evaluation results of physical properties.

  As shown in the table of FIG. 7, in Examples 1 to 4, the positive plate lattice uses an expanded lattice produced by the reciprocating expand method, and the negative plate lattice uses a lattice produced by the casting method. The ratio of the ear cross-sectional area of the positive electrode plate to the ear cross-sectional area of the negative electrode plate is 0.6 or more and less than 1.0, and the ratio of the sum of the ear cross-sectional areas of the plurality of positive electrode plates to the sum of the ear cross-sectional areas of the plurality of negative electrode plates Is set to 0.5 to 0.8. In addition to this, bus bars with different polarities of adjacent single cells are directly welded without connecting poles, and the individual cells are connected in series, resulting in better high-rate discharge life characteristics. Eliminating the effects of current collection and battery capacity.

  On the other hand, in Comparative Examples 1 and 2, the ratio of the ear cross-sectional area of each positive electrode plate to the cross-sectional area of each negative electrode plate exceeds 1.0, and each positive electrode plate with respect to the sum of the cross-sectional area of each negative electrode plate As a result of the ratio of the sum of the cross-sectional areas of the ears exceeding 0.8, the high-rate discharge life characteristics deteriorated. Moreover, in Comparative Example 1, as a result of adopting the conventional indirect connection method using the pole pole, the pole pole affects the current collecting performance, the high rate discharge life characteristics are remarkably deteriorated, and the battery volume becomes excessive. . In Comparative Example 3, the ratio of the ear cross-sectional area of each positive electrode plate to the ear cross-sectional area of each negative electrode plate is less than 0.6, and the ear cross-sectional area of each positive electrode plate with respect to the sum of the ear cross-sectional areas of each negative electrode plate As a result of the total ratio being less than 0.5, the high rate discharge life characteristics also deteriorated.

  In Examples 5 and 6, the numbers of the positive electrode plate and the negative electrode plate of one single cell in Examples 1 to 4 are changed. As a result, a lead storage battery having good high-rate discharge life characteristics and a small battery volume was obtained.

  In Example 7, each of the positive electrode plate lattice and the negative electrode plate lattice is produced by a reciprocating expand method and employs an expanded lattice, but only the positive electrode plate lattice is produced by a reciprocating expand method and Example 2 is employed. Compared with 3, 5, and 6, no substantial change in the high rate discharge life characteristics is observed. The reason for this is that, as described above, the positive electrode plate lattice and the negative electrode plate lattice are produced by the reciprocating expand method, respectively, and when the expanded lattice is adopted, the negative electrode expanded lattice also has no lateral bone. Is suppressed. On the other hand, since the electroconductivity of a positive electrode is raised relatively, there exists a possibility that the effect of this invention cannot be improved.

  In Examples 8, 9 and 10, while preparing the positive electrode plate by the reciprocating expand method in Examples 1 to 6, the degree of bending T / W of the grid of the positive electrode plate and the overfilling rate P / T of the lead paste are appropriate. As a result of controlling the range, the stress generated in the mesh of the lattice during processing can be reduced, and the current collecting property is appropriately reduced. The positive electrode active material at the time of high-rate discharge does not cause overdischarge, and corrosion due to stress hardly occurs. For this reason, the high-rate discharge life characteristics can be greatly improved.

  On the other hand, the main difference between Comparative Example 4 and Example 9 is that an indirect connection method using a conventional pole pole is adopted, and as a result, the high-rate discharge life characteristics are deteriorated, and the battery volume is reduced. Becomes excessive.

  As described above, in the present invention, overdischarge of the positive electrode active material must be avoided so that high rate discharge can be performed even in a shallow depth of charge (SOC) state and a long lifetime is obtained. The following two technical measures are taken. (1) By reducing the cross-sectional area of the positive electrode, the current collecting property is appropriately reduced. In addition, the bus bars of adjacent single cells are not welded using pole columns but are directly welded. To do. Thereby, the connection state between the single cells is stabilized, the fluctuation of the current collecting property between the single cells is very small, and the life can be extended. (2) In the above (1), the lattice bending degree T / W of the positive electrode plate produced by the reciprocating expand method and the ratio P / T of the lead paste overfilling ratio are within appropriate ranges, and the lattice is obtained using the reciprocating expand method. Apply little pressure to the intersection of lines. Thereby, a positive electrode plate lattice with a large curvature can be formed. Moreover, since there is almost no intersection where pressure is applied, it is not corroded because it is not subjected to pressure. As a result, high rate discharge characteristics and long life characteristics are improved. The lattice bending degree T / W is preferably in the range of 1.60 to 1.80, and the lead paste overfill ratio P / T is preferably in the range of 1.14 to 1.30. Further, in the above two technical means, the same effect can be obtained even if the number of electrode plates is increased (positive / negative = 6/7 or 9/10). Furthermore, even if the type of the negative electrode plate lattice is changed (expanded lattice produced by the reciprocating expand method or lattice produced by the casting method), the same effect can be obtained.

1 Lead acid battery
2 Positive plate
3 Negative electrode plate
4 Separator
5 Negative bus bar
6 Positive bus bar
7 Expanded lattice
8 Metal plate
9 Positive electrode ear
10 Negative electrode ear
11 electrode plate group
12 Single cell
13 Isolation wall
14 Single cell room
15 Battery cover
16 Positive terminal
17 Negative terminal
18 valves
19 Casing
21 Positive current collector (positive plate grid)
23 sides
24 Positive electrode active material layer
24a Lead paste
25 mesh
27 Lead sheet
31 Negative electrode current collector (negative electrode plate grid)
33 Upper frame
34 Negative electrode active material layer
35 mesh

Claims (17)

A lead acid battery comprising a plurality of unit cells,
The single cell is
An electrode plate group in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately arranged via separators;
A single cell chamber for accommodating the electrode plate group together with an electrolyte,
The positive electrode plate includes a positive electrode current collector having an ear part, and a positive electrode active material held by the positive electrode current collector,
The negative electrode plate includes a negative electrode current collector having an ear part, and a negative electrode active material held by the negative electrode current collector,
In the single cell,
The plurality of positive plates are connected in parallel with a positive bus bar connected to the ear,
The plurality of negative plates are connected in parallel with a negative bus bar connected to the ear,
The ratio (K / L) of the ear cross-sectional area (K) of the positive electrode plate to the ear cross-sectional area (L) of the negative electrode plate is 0.6 or more and less than 1.0,
In the adjacent single cells,
The lead acid battery in which the positive electrode bus bar of one single cell and the negative electrode bus bar of the other single cell are directly connected. The lead acid battery according to claim 1,
The lead acid battery in which the ratio of the sum of the ear cross-sectional areas of the plurality of positive electrode plates to the sum of the ear cross-sectional areas of the plurality of negative electrode plates is 0.5 to 0.8. The lead acid battery according to claim 1,
The lead acid battery, wherein a ratio of an ear cross-sectional area (K) of each positive electrode plate to an ear cross-sectional area (L) of the negative electrode plate is 0.74 to 0.93. In the lead acid battery according to claim 2,
The lead acid battery in which the ratio of the sum of the cross-sectional areas of the plurality of positive electrode plates to the sum of the cross-sectional areas of the plurality of negative electrode plates is 0.59 to 0.78. In the lead acid battery described in any one of Claims 1-4,
The lead storage battery, wherein the number of the plurality of positive plates is three or more and the number of the plurality of negative plates is four or more. In the lead acid battery according to claim 5,
The number of the plurality of negative electrode plates is greater than the number of the plurality of positive electrode plates, the number of the plurality of positive electrode plates is 4 to 9, and the number of the plurality of negative electrode plates is 5 to 10 or more. Lead acid battery. In the lead acid battery described in any one of Claims 1-4,
The lead-acid battery, wherein the thickness of the ear portion of the positive electrode plate is smaller than the thickness of the ear portion of the negative electrode plate. In the lead acid battery described in any one of Claims 1-4,
The lead storage battery, wherein the total thickness of the ears of the plurality of positive plates is smaller than the total thickness of the ears of the plurality of negative plates. In the lead acid battery described in any one of Claims 1-4,
The lead-acid battery in which the width of the ear portion of the positive electrode plate is 5 to 8 mm, and the width of the ear portion of the negative electrode plate is 5 to 7 mm. In the lead acid battery described in any one of Claims 1-4,
A lead-acid battery having two or more single cells. In the lead acid battery described in claim 10,
A lead acid battery having 4 to 8 single cells. In the lead acid battery described in any one of Claims 1-4,
The positive electrode current collector is a lead storage battery made of an expanded lattice produced by a reciprocating expand method. In the lead acid battery described in Claim 12,
The expanded lattice has a mesh formed by intersecting a plurality of lattice lines, and when the width of the lattice line is W and the thickness of the lattice is T, a ratio (T / Lead acid battery in which W) is in the range of 1.60 to 1.80. In the lead acid battery described in Claim 12,
The expanded grid is filled with a lead paste as a positive electrode active material. When the thickness of the positive electrode plate filled with the lead paste is P and the thickness of the grid is T, the overfill rate of the lead paste is A lead acid battery having a ratio (P / T) in the range of 1.14 to 1.30. In the lead acid battery described in any one of Claims 1-4,
The negative electrode current collector is a lead storage battery comprising a lattice produced by a casting method.   The electric vehicle provided with the lead storage battery as described in any one of Claims 1-4 as a power supply for motive power. The electric vehicle according to claim 16, wherein
The electric vehicle is an electric vehicle, an electric bicycle, an electric motorcycle, an electric scooter, or a moped electric motorcycle.

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