JP2007059171A - Lead-acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular lead-acid storage battery having an inter-cell connection part with high reliability by restraining abnormal heat generation at the inter-cell connection part while reducing the resistance and weight of a strap body. <P>SOLUTION: The lead-acid storage battery has electrode groups of which a plurality of ears of homopolar electrode plates are collectively welded by a plate shaped strap made of pure lead or a lead alloy, and the plurality of electrode plates are housed in cell chambers demarcated by separation walls, and a connection body for inter-cell connection is formed at one end of the strap, and the connection body formed on adjacent electrode groups has the inter-cell connection part connected through a through hole formed at the separation wall. Provided that the width of the strap at the position of the ear nearest to the connection body is A, and the width of the strap at the position of the ear farthest from the connection body is B, A>B is satisfied, and a length C in the width direction of the inter-cell connection part is made longer than B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lead-acid battery.

  In order to suppress global warming and save energy, recent automobiles are considering hybrid systems and idle stop systems aimed at reducing exhaust emissions and improving fuel efficiency. Nickel-hydrogen batteries and lithium-ion batteries are mainly used in these systems, but lead-acid batteries with excellent cost performance are still promising options.

  In lead storage batteries used in vehicles equipped with the hybrid system and idle stop system as described above, compared to lead storage batteries for starting used in conventional vehicles, high current discharge due to engine starting and motor driving performed at a high frequency, Furthermore, since regenerative charging repeats large current charging, it is necessary to reduce the resistance of the straps that collectively weld the plates and the cell connection portions that connect the straps together with increasing the output of the plates alone.

  On the other hand, since the strap and the connection part between cells are formed of lead or a lead alloy, the ratio to the battery mass is high. Therefore, when the cross-sectional area of the strap and the connection part between cells is increased for the purpose of reducing the resistance, the battery mass also increases, so that the output efficiency (Wh / kg) per battery mass decreases.

  In the conventional electrode group of lead-acid batteries for starting, the strap structure is a rectangular parallelepiped whose thickness is substantially constant and the length of the side provided with the connecting body is substantially equal to the length of the side facing the side. Is generally the same in any part.

  For example, Patent Document 1 proposes a method for welding a strap by a cast-on-strap method using electromagnetic induction heating and an ear portion of the same polarity plate for the purpose of manufacturing a thin and stable welded strap. Has been. Also in the welding method, the strap shape is a substantially rectangular parallelepiped, and the cross-sectional area is almost the same in any part.

  On the other hand, there are some types of stationary lead-acid batteries having a large capacity of several hundred to 1000 Ah, where the number of electrode plates in the electrode plate group is several tens. In such a case, the same current does not flow through the entire strap, but the current flowing through the strap increases as the inter-cell connection portion is approached. Therefore, as described above, when the strap shape is a rectangular parallelepiped, and the cross-sectional area does not change depending on the distance from the inter-cell connecting portion, the current flowing at the end of the strap that does not form the connecting body is small, and the strap cross-sectional area is larger than necessary. On the other hand, the current flowing at the end of the strap where the connection body is formed is large, the strap cross-sectional area per current is reduced, and the heat generation at this portion becomes remarkable.

  Patent Document 2 proposes a structure in which the cross-sectional area of the strap is increased in the vicinity of the pole column where current is concentrated, and the cross-sectional area of the strap is decreased as the distance from the pole column increases.

In Patent Document 2, by securing the cross-sectional area of the portion of the strap closer to the pole, the current per cross-sectional area of the strap is made more uniform between the strap portions, thereby reducing the strap weight and suppressing abnormal heat generation. Is what you get.
JP-A-8-255608 JP 2000-173579 A

  However, Patent Document 2 relates to a lead storage battery in which a pole is provided with a pole and the pole is connected to a battery terminal.

  When the strap shape shown in Patent Document 2 is applied to a lead storage battery having a structure in which a plurality of adjacent electrode plate groups are connected through a through hole provided in a partition wall of a cell chamber, the conventional rectangular parallelepiped shape Compared to the strap, the electrical resistance of the strap is lower. As a result, when the current flowing through the inter-cell connection portion increases, the inter-cell connection portion abnormally generates heat, the partition wall is thermally deformed, and the sealing property between the through hole and the inter-cell connection portion may be impaired.

  The present invention provides a lead-acid storage battery that connects a plurality of electrode plate groups through a through hole provided in a cell chamber partition wall, and suppresses abnormal heat generation at the connection part between cells while reducing the resistance and weight of the strap body. By doing so, a lead storage battery having a highly reliable inter-cell connection is provided.

  In order to solve the above-described problem, the invention according to claim 1 of the present invention is such that the ears of a plurality of homopolar plates are collectively welded with a plate-like strap formed of pure lead or a lead alloy. A plurality of the electrode plate groups are housed in a cell chamber partitioned by a partition wall, and a connection body for inter-cell connection is erected at one end of the strap, and the electrode plates are adjacent to each other The connection body provided in a group is a lead storage battery having an inter-cell connection portion connected through a through-hole provided in the partition wall, and the strap width at the ear portion position closest to the connection body is set. A, where B is the strap width at the ear portion position farthest from the connection body, and A> B, and the width dimension C in the width direction of the inter-cell connection portion is greater than B. It shows a lead-acid battery characterized by being lengthened.

  Furthermore, the invention according to claim 2 of the present invention is the lead storage battery of claim 1, wherein the strap has a substantially constant thickness.

  Furthermore, the invention according to claim 3 of the present invention is characterized in that, in the lead storage battery of claim 1 or claim 2, the length dimension C is made larger than the height dimension D of the inter-cell connecting portion. It is what.

  The lead-acid battery having the above-described configuration can improve the reliability of the inter-cell connecting portion by suppressing abnormal heat generation in the inter-cell connecting portion while reducing the resistance and weight of the strap body.

  The configuration of the lead storage battery of the present invention will be described with reference to the drawings.

  The lead storage battery 101 of the present invention is formed by collectively welding a plurality of pieces of the same polarity electrode plates 102 and 102 ′ with tab-like straps 104 and 104 ′ formed of pure lead or lead alloy. An electrode plate group 105 is provided. In FIG. 1, only one of the positive and negative polar plates constituting the polar plate group 105 is shown, and the other polar plate and separator are omitted.

  The plurality of electrode plate groups 105 are housed in a cell chamber 108 partitioned by a partition wall 107 in a battery case 106, and connecting members 109 and 109 'for connecting cells between the straps 104 and 104' are erected. The inter-cell connecting portion 111 is formed through the through hole 110 provided in the partition wall 107 by the connecting bodies 109 and 109 ′ provided in the electrode plate group 105 adjacent to each other.

  As shown in FIG. 2, in the lead storage battery of the present invention, the width dimension of the strap 104 (104 ′) at the position of the ear 103 (103 ′) closest to the connection body 109 (109 ′) is A, and the connection body. When the width of the strap 104 (104 ′) at the position of the ear 103 (103 ′) farthest from 109 (109 ′) is B, A> B and the length in the width direction of the inter-cell connecting portion 111 The dimension C is made longer than the strap width B. In FIG. 2, the A dimension, the B dimension, and the C dimension are displayed only on one strap 104, but each of the above dimensions is set at the same position on the other strap 104 '.

  Note that the thickness of the strap 104 (104 ′) is substantially constant except for a taper formed in consideration of mold separation from the mold. From the viewpoint of weldability and weldability between the ear portion 103 (103 ′) and the strap 104 (104 ′), the dimension B is at least larger than the width dimension B ′ of the ear portion 103 (103 ′). Accordingly, the dimension C is also larger than the width dimension B ′ of the ear portion. When the dimension B is equal to or smaller than the width dimension B ′ of the ear part, the ear part is exposed on the side surface of the strap, and it becomes difficult to completely cover the ear part with the strap part. It is not preferable because the mechanical strength of the strap is extremely lowered due to the decrease or the gap.

  The cross-sectional area in the longitudinal direction of the strap 104 (104 ′) decreases from one end having the connecting body 109 (109 ′) toward the other end. Almost the same current flows from the plurality of ears 103 (103 ′) and the current concentrates on the connection body 109 (109 ′) side of the strap 104 (104 ′), but the resistance is reduced by increasing the cross-sectional area. The strap structure that suppresses heat generation in this portion and is difficult to melt is obtained.

  In the present invention, in particular, the width dimension B of the strap 104 (104 ′) at the ear part 103 (103 ′) farthest from the connection body 109 (109 ′) is the length dimension C in the width direction of the inter-cell connection part 111. By making the length longer, heat generation at the inter-cell connection portion 111 is suppressed, and the partition 107 is deformed by melting or heat generation at this portion, and further, the sealing performance between the inter-cell connection portion 111 and the partition wall 107 is deteriorated due to this deformation. Therefore, it is possible to form a cell-to-cell connection portion with excellent reliability. In addition, what is necessary is just to perform the connection of connection bodies by the resistance welding and plasma welding method conventionally known.

  In the present invention, it is possible to suppress a partial increase in the current density of the inter-cell connecting portion 111 by ensuring that the width C of the inter-cell connecting portion is larger than the width B of the strap. Can be suppressed. As shown in the strap 301 shown in FIG. 3, when the width dimension C of the inter-cell connecting portion 302 is made smaller than the width dimension B of the strap, the lower edge portion 303 adjacent to the strap 301 of the inter-cell connecting portion 302 is It should be avoided because it suffers from thermal deformation and the sealing performance here is impaired.

  Further, in the present invention, since the length dimension in the width direction of the inter-cell connecting portion 111 may be set larger than the width dimension B of the strap, for example, as shown in FIG. If the length dimension C is set to be larger than the strap width dimension B and the length dimension C is made larger than the height dimension D of the inter-cell connecting portion 111, the connection body 109 (109 ') Since the height dimension can be suppressed, it is effective for downsizing the battery. Further, the position of the center P of the inter-cell connecting portion 111 is within the range of the B dimension of the strap 104 (104 ′), preferably within the range of the width dimension B ′ of the ear portion 103, and more preferably the width dimension of the ear portion 103. By setting the center P to be positioned at the center of B ′, the current path from the ear portion 103 to the inter-cell connection portion 111 can be shortened, so that the strap 104 (104 ′) and the connection body 109 (109 ′) Heat generation is suppressed.

  Further, although the strap 104 (104 ′) shown in FIG. 2 has a trapezoidal shape, the side in the strap longitudinal direction may be a curved line instead of a straight line. Further, instead of the strap 104 as shown in FIG. 2, a strap 502 (502 ′) in which a bent portion 501 is provided on the side surface as shown in FIG. In this case, the amount of lead used in the strap can be reduced, which is effective for reducing the weight of the battery. However, since stress concentrates on the bent portion 501, attention should be paid to the usage environment such as vibration.

  A 12V55Ah lead acid battery according to the present invention and a comparative example was prepared, and the voltage measurement at the 5th second at the time of 275A discharge and the airtight test between the connection part between the cells and the partition wall after the discharge of 1000A (end voltage 8.4V) were performed. .

(1) Battery 1 of the present invention example
The battery 1 of the present invention is a battery having the trapezoidal strap 104 (104 ′) shown in FIG. 2 and having a dimension A of 24.0 mm, a dimension B of 13.2 mm, and a dimension C of 17.0 mm. . The strap 104 has a length of 59.0 mm and a thickness of 5.0 mm. In addition, the connection part between cells was made into the ellipse of horizontally long with a major axis of 17.0 mm and a minor axis of 12.0 mm.

(2) Battery 1 'of the present invention example
The battery 1 of the present invention is a battery having the trapezoidal strap 104 (104 ′) shown in FIG. 2 and having a dimension A of 24.0 mm, a dimension B of 13.2 mm, and a dimension C of 17.0 mm. . The strap 104 has a length of 59.0 mm and a thickness of 5.0 mm. In addition, the connection part between cells was made into the circular shape of diameter 17.0mm.

(3) Battery 2 of the present invention example
The battery 2 of the example of the present invention has the strap 502 (502 ′) having the bent portion 501 shown in FIG. 5, the dimension A is 24.0 mm, the dimension B is 13.2 mm, and the dimension C is 17.0 mm. It is a battery. The strap 502 has a length of 59.0 mm and a thickness of 5.0 mm. The bent portion 501 is a midpoint portion of the length dimension of the strap 502. In addition, the connection part between cells was made into the circular shape of diameter 17.0mm.

(4) Battery 3 of comparative example
The battery 3 of the comparative example is a battery in which each dimension of the strap 104 (104 ′) of the battery 1 of the present invention is changed. The dimension A of 24.0 mm and the dimension B of 13.2 mm are the same as the battery 1 of the present invention example, but the dimension C was set to 12.0 mm. The length and thickness of the strap are 59.0 mm and 5.0 mm, respectively. In addition, the connection part between cells was made into the circle of diameter 12.0mm.

(5) Battery 3 'of comparative example
The battery 3 of the comparative example is a battery in which each dimension of the strap 104 (104 ′) of the battery 1 of the present invention is changed. The dimension A of 24.0 mm and the dimension B of 13.2 mm are the same as the battery 1 of the present invention example, but the dimension C was set to 12.0 mm. The length and thickness of the strap are 59.0 mm and 5.0 mm, respectively. In addition, the connection part between cells was made into the elliptical ellipse of 12.0 mm of short diameters, and 17.0 mm of long diameters.

(6) Battery 4 of comparative example
The battery 4 of the comparative example has a rectangular parallelepiped strap 601 (601 ') shown in FIG. 6, and has a dimension A of 13.2 mm, a dimension B of 13.2 mm, and a dimension C of 12.0 mm. . The length and thickness of the strap are 59.0 mm and 5.0 mm, respectively. In addition, the connection part between cells was made into the circle of diameter 12.0mm.

(7) Battery 5 of comparative example
The battery 5 of the comparative example has a rectangular parallelepiped strap 601 (601 ') shown in FIG. 6, and has a dimension A of 13.2 mm, a dimension B of 13.2 mm, and a dimension C of 17.0 mm. . The length and thickness of the strap are 59.0 mm and 5.0 mm, respectively. In addition, the connection part between cells was made into the circular shape of diameter 17.0mm.

  The thickness of the ear | edge part of the positive electrode plate of each said battery and a negative electrode plate is 0.8 mm, and width | variety is 10.0 mm. The dimension A is the strap width dimension at the side of the connection part of the ear part closest to the connection object, and the dimension B is the strap width dimension at the side surface opposite to the connection part of the ear part farthest from the connection object. It is. Moreover, the center of the connection part between cells of each battery was made to correspond with the center of the width direction of the ear | edge part. In addition, the specifications of the positive and negative electrode plates and the separator were the same for all the batteries in order to eliminate the influence of the distance between the electrodes and the group pressure. Moreover, welding of the connected bodies was performed by resistance welding. Table 1 shows the configuration of each of these batteries.

  Table 2 shows the results of the voltage at 30 seconds at 275 A discharge (25 ° C.) of each battery shown above.

  As is apparent from the results in Table 2, it is found that it is extremely effective to satisfy dimension A> dimension B and dimension C> dimension B in obtaining excellent discharge voltage characteristics. Further, when comparing the battery 1 and the battery 1 ′, the battery 1 ′ does not affect the voltage characteristics so much even though the cross-sectional area of the inter-cell connection portion is larger than that of the battery 1. The battery 1 and the battery 3 ′ have the same cross-sectional area at the inter-cell connection portion, but the battery 1 has remarkably superior voltage characteristics compared to the battery 3 ′. From these, it can be seen that the dimension in the width direction (lateral direction) of the connection part between cells significantly affects the voltage characteristics.

  Therefore, if the cross-sectional area of the connection part between the cells is the same, more excellent voltage characteristics can be obtained by adopting a horizontally long shape. In addition, since the battery can be reduced in size by adopting a horizontally long shape, it is also preferable in terms of battery size reduction.

  Next, each battery shown in Table 1 was discharged to 8.4 V at a high rate current of 1000 A (18.2 CA). Thereafter, the battery was disassembled, and the airtightness of the inter-cell connection portion and the partition wall was evaluated. As an evaluation method, two electrode plate groups connected through a partition are taken out from the battery together with the partition, and the electrode plate is removed from the strap to prepare a sample.

  Then, an airtight chamber covering one of the straps and in close contact with the partition wall was attached, and the inside of the airtight chamber was pressurized. When the internal pressure of the airtight chamber is monitored and the internal pressure decreases with time, it can be seen that the airtightness between the inter-cell connection portion and the partition wall is impaired. On the other hand, when the internal pressure does not change with time, it can be seen that the airtightness is maintained.

  As a result of the airtight test after the discharge, in the battery 1, the battery 1 ′, and the battery 2 of the present invention example, the airtightness between the inter-cell connection portion and the partition wall was maintained. On the other hand, in the batteries 3 and 4 of the comparative example, melting marks were observed in the inter-cell connection portions, and the airtightness between the inter-cell connection portions and the partition walls was impaired. On the other hand, in the batteries 3 ′ and 5 of the comparative example, no melting marks were observed in the inter-cell connection portions, and no abnormality was observed in appearance, but some melting occurred in the partition walls in contact with the inter-cell connection portions. There were traces, and the airtightness was impaired in this part.

  From the above, it can be seen that the configuration of the present invention is extremely effective in order to suppress a decrease in airtightness between the inter-cell connection portion and the partition wall due to heat generation in the inter-cell connection portion.

  Next, a vibration resistance test was performed on each battery shown in Table 1. Excitation conditions were random excitation reflecting the vibration characteristics in the market, the root mean square acceleration was 3.2 G, and the excitation time was set to 2 hours for each of the three axes, for a total of 6 hours. In the case of a vehicle battery, the 6 hours of excitation time corresponds to about 160,000 km of travel. The battery 1, the battery 1 'and the battery 2 of the example of the present invention, and the battery 3' and the battery 5 of the comparative example are welded between the strap and the connection body even when random vibration is applied for 6 hours in total for 2 hours for each of the three axes. No disconnection was observed at the part.

  Furthermore, when vibration was applied to the battery of the present invention, cracks occurred in the bent portion of the strap in the battery 2 of the present invention in 7 hours and 50 minutes. No cracks were observed. On the other hand, in the battery 3 and the battery 4 of the comparative example, the disconnection occurred in the connection part between cells by the vibration for 1 hour.

  From the above, it can be seen that in the present invention, an inter-cell connection portion and a strap excellent in vibration resistance can be obtained.

  The lead storage battery of the present invention is particularly suitable for a lead storage battery for a vehicle including an electric vehicle because it has excellent voltage characteristics and has excellent inter-cell connection reliability against large current discharge and vibration. It is.

The figure which shows a part of lead acid battery of this invention The figure which shows the principal part of the lead acid battery of this invention The figure which shows the connection part between the cells of the conventional lead acid battery The figure which shows the connection part between cells of the lead acid battery of this invention The figure which shows the principal part of the lead acid battery of this invention The figure which shows the principal part of the lead acid battery of a comparative example

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lead acid battery 102,102 'Electrode plate 103,103' Ear part 104,104 'Strap 105 Electrode board group 106 Battery case 107 Bulkhead 108 Cell chamber 109,109' Connection body 110 Through-hole 111 Inter-cell connection part 301 Strap 302 Cell Inter-connection part 303 Lower edge part 501 Bending part 502, 502 'Strap 601, 601' Strap 602 Inter-cell connection part

Claims (3)

A plurality of same polarity electrode plates have electrode plate groups formed by collective welding with plate-shaped straps made of pure lead or a lead alloy, and a plurality of the electrode plate groups are partitioned by partition walls. A connecting body is housed in the cell chamber, and a connection body for connecting the cells is erected at one end of the strap, and the connection body provided in the electrode plate group adjacent to each other is connected through a through hole provided in the partition wall. A lead-acid battery having a connection part between cells,
A strap width at the ear position closest to the connection body is A,
When the strap width at the ear part position farthest from the connection body is B, A> B,
And the length dimension C of the width direction of the said connection part between cells was made longer than said B, The lead acid battery characterized by the above-mentioned. The lead storage battery according to claim 1, wherein the strap has a substantially constant thickness. The lead acid battery according to claim 1 or 2, wherein, in the inter-cell connecting portion, the length dimension C is made larger than a height dimension D of the inter-cell connecting portion.

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