JP2020017459A - Lead acid battery - Google Patents

Abstract

To provide a means capable of preventing reduction of electrolyte.SOLUTION: A lead acid battery has a battery case and a lid member. The battery case has an opening, and multiple cell chambers communicating with this opening are sectioned in a prescribed direction. An electrolyte and an electrode group are housed in each cell chamber. The lid member has an air outlet, and seals the opening mentioned above. The lid member has an inner lid fixed to an upper part of the battery case mentioned above, and a top cover fixed to an upper part of the inner lid. An exhaust passage is formed between the top cover and the inner lid. The exhaust passage has a plurality of individual passages communicating with each of the cell chambers, and a common passage communicating with each individual passage and connected to the air outlet. A first filter is placed at the end of the exhaust passage on the air outlet side, and a second filter is placed midway of the common passage and in the central part of the lid member in the prescribed direction.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a structure of a lead storage battery.

  In a lead storage battery used for a vehicle or the like, gas generated inside the battery case is exhausted to the outside through an exhaust passage in order to suppress an increase in the internal pressure of the battery case. For example, in the lead storage battery described in Patent Literature 1, the lid member for closing the battery case has a double lid structure including an inner lid and an upper lid, and an exhaust passage is provided between the inner lid and the upper lid. A porous filter is provided at the end of the exhaust passage.

JP-A-2006-189290

  In a lead-acid battery provided with an exhaust passage, the amount of electrolyte is reduced because moisture evaporated from the electrolyte and mist of the electrolyte are discharged to the outside through the exhaust passage. When the amount of electrolyte decreases, it is necessary to replenish the battery tank with purified water. In order to reduce the frequency of this operation, it is preferable that the reduction of the electrolytic solution is suppressed.

  Then, an object of the present invention is to provide a means capable of suppressing the decrease of the electrolytic solution.

  A lead storage battery according to one embodiment of the present invention has an opening, a battery case in which a plurality of cell chambers communicating with the opening and containing an electrolyte and an electrode group are partitioned along a predetermined direction, and an exhaust port. And a lid member for sealing the opening. The lid member is formed between the inner lid fixed to the upper part of the battery case, the upper lid fixed to the upper part of the inner lid, and the upper lid and the inner lid, and communicates with each of the cell chambers. An exhaust passage having a plurality of individual passages and a common passage communicating with the individual passages and connected to the exhaust port; a first filter disposed at an end of the exhaust passage on the exhaust port side; And a second filter arranged at the center of the lid member in the predetermined direction.

  According to the lead storage battery of one embodiment of the present invention, a decrease in the amount of the electrolytic solution is suppressed.

Perspective view of lead storage battery Top view of battery case Vertical sectional view of the lead-acid battery (A-A sectional view in FIG. 1) Top view of inner lid Bottom view of inner lid Top view of top lid Bottom view of top lid FIG. 4 is an enlarged view of a part of FIG. FIG. 7 is an enlarged view of a part of FIG. Plan view showing structure of intermediate filter unit 4 (plan view of lid member) Vertical sectional view (BB sectional view in FIG. 10) showing the structure of the intermediate filter unit 4. Plan view showing structure of intermediate filter unit 4 (plan view of lid member) Vertical sectional view showing the structure of the intermediate filter unit 4 (a sectional view taken along line CC in FIG. 12).

[Overview]

  First, an outline of a lead storage battery according to an embodiment of the present invention will be described. This lead storage battery includes a battery case and a lid member. The battery case has an opening, and a plurality of cell chambers communicating with the opening and containing the electrolyte and the electrode group are partitioned along a predetermined direction. The lid member has an exhaust port and seals the opening. The lid member has an inner lid fixed to the upper part of the battery case, and an upper lid fixed to the upper part of the inner lid. The lid member is formed between the upper lid and the inner lid, and has an exhaust passage having a plurality of individual passages communicating with each of the cell chambers and a common passage communicating with the individual passages and connected to the exhaust port. A first filter disposed at an end of the exhaust passage on the exhaust port side; and a second filter disposed in the middle of the common passage in the predetermined direction of the lid member.

  The present inventor has studied to increase the ventilation resistance of the exhaust passage in order to suppress the decrease in the electrolytic solution. When the ventilation resistance increases, the amount of gas discharged to the outside through the exhaust passage decreases, and accordingly, the amount of water vapor and electrolyte mist discharged to the outside decreases. As means for increasing the ventilation resistance, it is conceivable to make the size of the porous filter arranged in the exhaust passage small for the purpose of preventing the intrusion of the external spark. However, when the size of the filter is fine, clogging of the filter due to dust or the like is likely to occur.

  Then, the inventor came up with the idea of arranging two identical filters in series in the exhaust passage and doubling the ventilation resistance of the filters, and conducted an experiment to measure the amount of decrease in the electrolyte. As expected, the volume reduction with two filters was less than the volume reduction with one filter. In this experiment, the inventor discovered an unexpected strange phenomenon. That is, the amount of liquid reduction when the two filters are arranged apart from each other is smaller than the amount of liquid reduction when the two filters are arranged in contact with each other.

  The reason why the amount of liquid reduction is further reduced when the two filters are arranged apart from each other is not clear, but is presumed as follows. The above-described experiment for measuring the amount of decrease in the electrolytic solution is performed by simulating an actual use environment in a vehicle or the like and applying a vertical vibration to the lead storage battery in a high-temperature environment. When two filters are arranged in contact with each other, the space on the battery case side of the filters (hereinafter, referred to as a “container side space”) is filled with water vapor and the electrolyte mist, resulting in a high humidity state. . The space on the exhaust port side of the filter (hereinafter, referred to as “exhaust port side space”) communicates with the outside of the lead storage battery, and has a low humidity.

  When the liquid level in the battery case fluctuates due to vibration, gas is pushed out of the battery case, or gas is sucked into the battery case from the outside. When gas is extruded from the battery case, water vapor and mist contained in the extruded air are released to the outside of the lead storage battery. Next, when gas is sucked into the battery case from the outside by vibration, the sucked gas is a gas having a low humidity outside the lead storage battery. The vaporization of the electrolytic solution in the inside proceeds. By repeating the movement of these gases, the water vapor and the mist in the battery case are released to the outside of the lead storage battery.

  On the other hand, when the two filters are arranged apart from each other, a space (hereinafter, referred to as “intermediate space”) exists between the battery case filter and the exhaust port filter. First, the space on the battery case side (the battery case side space) of the battery case side filter is filled with water vapor and the electrolyte mist, and the humidity is high, as in the case described above. The space on the exhaust port side of the exhaust port filter (exhaust port side space) communicates with the outside of the lead storage battery, and the humidity is low as in the case described above. Then, the intermediate space is considered to have an intermediate humidity between the battery case side space and the exhaust port side space. That is, from the difference in humidity between the battery case side space and the exhaust port side space when there is one filter, between the battery case side space and the intermediate space when there are two filters, and It is considered that the difference in humidity between the intermediate space and the exhaust side space becomes smaller.

  When the liquid level in the battery case fluctuates due to vibration, gas exchange occurs between the battery case and the battery case side space, between the battery case side space and the intermediate space, and between the intermediate space and the exhaust port side space. Is performed. At that time, gas flows in and out of the container-side space and the intermediate space, because of a small difference in humidity, the gas flows between the container-side space and the exhaust-side space when there is only one filter. It is thought that it is restrained compared to entering and leaving. Similarly, gas enters and exits between the intermediate space and the exhaust-port-side space due to the small difference in humidity between the container-side space and the exhaust-port-side space when only one filter is used. It is thought that it is restrained compared to entering and leaving.

  In addition, when the two filters are arranged without a sufficient separation distance, it is assumed that the above-described unexpected effect of suppressing the liquid reduction amount cannot be sufficiently obtained. Because, if the intermediate space between the two filters does not have a sufficient volume, when the movement of the gas by vibration occurs, the humid gas in the battery case space does not stay in the intermediate space, This is because it is conceivable that the gas is released into the exhaust port side space. From this, it is considered that it is necessary to separate the two filters with a sufficient distance in order to suppress the decrease in the electrolytic solution. Therefore, if one filter is arranged at the end on the exhaust port side of the exhaust passage and the other filter is arranged at the center of the cover member in the predetermined direction, it is possible to have a sufficient volume as an intermediate space, The electrolyte solution can be prevented from decreasing.

  When a lead storage battery is used, the amount of the electrolyte generally decreases as described above. However, a phenomenon occurs in which the degree of the reduction differs between the cells. For example, in a normal use state of a lead-acid battery (typically installed in an engine room of an automobile), heat in the engine room raises the temperature of the lead-acid battery. The placed cells are more strongly affected by heat and become hotter. Therefore, it is considered that the evaporation of the electrolytic solution proceeds, and the amount of reduction increases. In the present invention, since the second filter is arranged at the center of the common passage, the distance from each cell to the second filter is longer in the cells arranged outside the battery case than inside. Due to the difference in the distance, it is conceivable that the electrolytic solution once vaporized once again liquefies in the individual passages in the cells arranged on the outside in the individual passages, and is easily returned to the respective cells. That is, the difference in the amount of reduction of the electrolyte between the cells is reduced.

  Further, since the second filter is disposed in the common passage, the cells communicate with each other without the filter. In this case, it is considered that the behavior of the water vapor and the electrolyte mist in the battery case-side space corresponding to each cell works to alleviate the imbalance of humidity, pressure, and the like among the cells. That is, the difference in the amount of reduction of the electrolyte between the cells is further reduced.

  As an embodiment of the lead storage battery, the length of the individual passage from the cell chamber located at the end in the predetermined direction to the second filter is equal to the length of the exhaust passage from the remaining cell chamber to the second filter. It is preferable that the length is set longer than the length.

[Detailed explanation]

  Hereinafter, a lead storage battery according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

1. Overall configuration

  As shown in FIGS. 1 and 3, the lead storage battery 1 is a liquid storage battery including a flowable electrolyte. As shown in FIG. 2, the lead storage battery 1 includes a battery case 17, an electrode plate group 30 and an electrolyte 14 (see FIG. 3), terminals 38 and 39, and a cover member 45. 1 and 3 show a posture of the lead storage battery 1 in a normal use state. In this state, the installation surface on which the lead storage battery 1 is installed extends along the horizontal direction, and in this specification, the direction perpendicular to this installation surface is defined as the up-down direction 11. The direction of the width of the battery case 17, that is, the direction of an imaginary line connecting the terminal 38 and the terminal 39 in FIG. 1 is defined as the left-right direction 13 (corresponding to the "predetermined direction" described in the claims), The depth direction of the battery case 17 is defined as the front-back direction 12. The side where the terminal portions 38 and 39 are arranged in the front-rear direction 12 is defined as the rear side.

  The battery case 17 is a box-shaped member made of a synthetic resin, and includes four outer walls 27 and a bottom wall 28. Two of the four outer walls 27 face the front-rear direction 12, and the remaining outer walls 27 face the left-right direction 13. The upper surface of the battery case 17 is open, and an opening 18 is formed. A storage chamber 19 is formed continuously from the opening 18. As shown in FIG. 2, five partition walls 29 are arranged in the accommodation room 19 at equal intervals along the left-right direction 13. The partition walls 29 and the outer wall 27 form six cell chambers 21 to 26 in order from right to left. In each of the cell chambers 21 to 26, an electrolytic solution 14 made of dilute sulfuric acid and an electrode plate group 30 are accommodated. That is, six cell chambers 21 to 26 containing the electrode group 30 and the electrolytic solution 14 are partitioned in the housing chamber 19 along the left-right direction 13. In the present embodiment, the inner surface shape of each of the cell chambers 21 to 26 is rectangular, and the dimension of each of the cell chambers 21 to 26 in the front-rear direction 12 (longitudinal direction) is larger than the dimension in the left-right direction 13 (short direction). . The dimension in the front-rear direction 12 of each of the cell chambers 21 to 26 is preferably 2.5 times or more, and preferably 6.3 times or less, the dimension in the left-right direction 13. As illustrated in FIG. 2, it is more preferable that the dimension of the cell chambers 21 to 26 in the front-rear direction 12 is 4.1 times the dimension in the left-right direction 13.

  The electrode plate group 30 includes a positive electrode plate 31, a negative electrode plate 32, and a separator 33, as shown in FIG. The separator 33 is disposed between the positive electrode plate 31 and the negative electrode plate 32, and separates the positive electrode plate 31 from the negative electrode plate 32. The positive electrode plate 31 and the negative electrode plate 32 are configured by filling a grid with an active material. The main component of the active material of the positive electrode plate 31 is lead dioxide, and the main component of the active material of the negative electrode plate 32 is lead.

  An ear 34 is provided above the positive electrode plate 31, and an ear 35 is provided above the negative electrode plate 32. Inside the cell chambers 21 to 26, the ears 34 are connected to the strap 36 for the positive electrode, and the ears 35 are connected to the strap 36 for the negative electrode. The strap 36 is a plate-shaped member extending in the left-right direction 13 (a direction perpendicular to the paper surface in FIG. 3). Thereby, the positive electrode plate 31 in each of the cell chambers 21 to 26 is electrically connected by the positive electrode strap 36, and the negative electrode plate 32 in each of the cell chambers 21 to 26 is electrically connected by the negative electrode strap 36. ing. The positive and negative straps 36 of the adjacent cell chambers 21 to 26 are electrically connected to each other via a connection portion 37 formed on the strap 36. As a result, the electrode groups 30 of the six cell chambers 21 to 26 are electrically connected in series.

  As shown in FIG. 3, the lid member 45 has a middle lid 50 and an upper lid 100, and is provided with an exhaust port 201 (see FIGS. 1 and 7) described later. FIG. 4 is a plan view of the inner lid 50 (in a state where the upper lid 100 is removed), and FIG. 5 is a bottom view of the inner lid 50 as viewed from below.

  The inner lid 50 is fitted into the battery case 17 and seals the opening 18. The upper lid 100 is provided on the inner lid 50. The inner lid 50 is made of a synthetic resin, and includes a lid plate 51 and a flange portion 52, as shown in FIGS. The flange portion 52 is formed along the periphery of the cover plate 51 (see FIGS. 3 and 5). In the present embodiment, the exhaust port 201 is formed on the right side surface of the upper lid 100, as shown in FIG.

  The cover plate 51 is a member having a size corresponding to the opening 18 and securely seals the opening 18. As shown in FIG. 5, a peripheral wall 53 is formed on the lower surface of the lid plate 51 along the flange 52, and a plurality of lid-side partition walls 54 are formed continuously from the peripheral wall 53.

  The peripheral wall 53 protrudes downward from the lower surface of the cover plate 51. The peripheral wall 53 is formed in a substantially rectangular ring shape, and corresponds to the peripheral shape of the opening 18 of the battery case 17. The lid-side partition wall 54 protrudes downward from the lower surface of the lid plate 51. Each lid-side partition 54 partitions the inside of the peripheral wall 53 and faces each partition 29 of the battery case 17 (see FIG. 2). The peripheral wall 53 is overlapped on the periphery of the opening 18 of the battery case 17, the lid-side partition wall 54 is overlapped on the partition wall 29 of the battery case 17, and joined by heat treatment (thermal welding). Thereby, airtightness between the peripheral wall 53 and the battery case 17 and between the lid-side partition wall 54 and the partition wall 29 are ensured.

  As shown in FIGS. 1 and 3, the cover plate 51 includes a high surface portion 55 and a low surface portion 56. The high surface portion 55 is provided at the front and rear of the cover plate 51. A pair of terminal portions 38 and 39 are arranged at both ends in the left-right direction 13 of the rear high surface portion 55. More specifically, the positive terminal portion 38 is disposed at the left end of the rear high surface portion 55, and the negative terminal portion 39 is disposed at the right end. Since the positive terminal section 38 and the negative terminal section 39 have substantially the same shape, the negative terminal section 39 will be described below as an example, and the description of the positive terminal section 38 will be omitted.

  As shown in FIG. 3, the negative terminal portion 39 includes a bushing 41 and a pole 42. The bushing 41 is made of a metal such as a lead alloy, and is a hollow cylindrical member. A tubular mounting portion 67 is formed on the high surface portion 55, and the bushing 41 is mounted on the mounting portion 67. The bushing 41 penetrates the mounting portion 67, and the upper portion of the bushing 41 protrudes from the upper surface of the high surface portion 55. An upper portion of the bushing 41, that is, a portion protruding from the high surface portion 55 constitutes a terminal connection portion, and a connection terminal (not shown) such as a harness terminal is attached to the terminal connection portion.

  The pole 42 has a columnar shape and is made of a metal such as a lead alloy. The pole 42 is located inside the bushing 41. The pole 42 is longer than the bushing 41. The upper part of the pole 42 is inserted into the bushing 41, and the lower part of the pole 42 projects downward from the lower surface of the bushing 41. The upper end (tip) of the pole 42 is welded to the bushing 41, and the base 43 of the pole 42 is joined to the strap 36 of the electrode plate group 30.

  As shown in FIGS. 1 and 3, the lower surface portion 56 of the inner lid 50 is formed closer to the front of the lid plate 51. The low surface portion 56 extends in the left-right direction 13 (a direction perpendicular to the paper surface in FIG. 3) across each of the cell chambers 21 to 26. The upper surface of the low surface portion 56 is located lower than the upper surface of the high surface portion 55.

  As shown in FIGS. 4 and 5, six liquid injection holes 68 are provided in the upper surface wall 57 of the lower surface portion 56 of the inner lid 50. The liquid injection holes 68 are juxtaposed along the left-right direction 13. Each liquid injection hole 68 penetrates the upper surface wall 57 of the lower surface portion 56 in the up-down direction 11, and communicates with the six cell chambers 21 to 26, respectively.

  As shown in FIG. 4, the low surface portion 56 includes a lower cylindrical wall 69, a lower outer peripheral wall 70, and a lower partition 71. These protrude upward from the upper surface of the upper wall 57. The lower cylinder wall 69 is a cylindrical partition surrounding the liquid injection hole 68, and is provided in each of the six liquid injection holes 68. The lower outer peripheral wall 70 is a substantially rectangular partition wall provided along the outer edge of the low surface portion 56 and surrounding the low surface portion 56. The lower partition 71 is a partition extending forward from the lower outer peripheral wall 70 at the rear, and is provided corresponding to each partition 29 (see FIG. 2) of the battery case 17.

  The upper lid 100 is made of a synthetic resin. FIG. 6 is a plan view of the upper lid 100, and FIG. 7 is a bottom view of the upper lid. As shown in these drawings, the upper lid 100 includes a lid main body 101 and a flange portion 103. The lid body 101 is a rectangular member corresponding to the shape of the lower surface portion 56 of the inner lid 50, and is attached so as to overlap the lower surface portion 56 of the inner lid 50 (see FIGS. 1 and 3). The flange portion 103 is formed on the left and right outer edges of the lid main body 101. The flange portion 103 protrudes downward from the lid body 101 and is located outside the left and right ends of the low surface portion 56 of the inner lid 50.

  As shown in FIGS. 6 and 7, the upper surface wall 102 of the lid main body 101 includes six liquid injection holes 104 arranged in the left-right direction 13. Each liquid injection hole 104 is formed at a position corresponding to the liquid injection hole 68 (see FIG. 4) of the inner lid 50. Each liquid injection hole 104 penetrates the upper surface wall 102 of the lid main body 101 in the vertical direction 11 (a direction perpendicular to the paper surface), and communicates with the six cell chambers 21 to 26, respectively. The electrolyte 14 is injected into each of the cell chambers 21 to 26 through each injection hole 104 and each injection hole 68. As shown in FIG. 1, a liquid port plug 105 is attached to each liquid injection hole 104, and the liquid injection port 104 is closed by the liquid port plug 105.

  The lid main body 101 includes an upper cylindrical wall 106, an upper outer peripheral wall 107, and an upper partition 108. These protrude downward from the lower surface of the upper wall 102. The upper cylindrical wall 106 is a cylindrical partition surrounding the liquid injection hole 104, and is provided in each of the six liquid injection holes 104. The upper outer peripheral wall 107 is a substantially rectangular partition wall, and is provided inside the flange portion 103 along the outer edge of the main body 101. The upper partition 108 is a partition extending forward from the rear upper outer peripheral wall 107. The upper partition 108 is provided corresponding to each partition 29 of the battery case 17.

  Each upper cylinder wall 106 corresponds to each lower cylinder wall 69. When the upper lid 100 is disposed on the lower surface portion 56 of the inner lid 50, each upper cylindrical wall 106 is disposed so as to overlap above each lower cylindrical wall 69. Each upper cylinder wall 106 and each lower cylinder wall 69 are joined by heat welding, and airtightness between each upper cylinder wall 106 and each lower cylinder wall 69 is ensured.

  The upper outer peripheral wall 107 corresponds to the lower outer peripheral wall 70. When the upper lid 100 is disposed on the lower surface portion 56 of the inner lid 50, the upper outer peripheral wall 107 is disposed so as to overlap above the lower outer peripheral wall 70. The upper outer peripheral wall 107 and the lower outer peripheral wall 70 are joined by heat welding, and airtightness between the upper outer peripheral wall 107 and the lower outer peripheral wall 70 is ensured.

  Each upper partition 108 corresponds to each lower partition 71. When the upper lid 100 is disposed on the lower surface portion 56 of the inner lid 50, each upper partition 108 is disposed so as to overlap above each lower partition 71. Each upper partition 108 and each lower partition 71 are joined by heat welding, and airtightness between each upper partition 108 and each lower partition 71 is ensured.

2. Exhaust passage

  As shown in FIGS. 4 and 7, the lid member 45 includes the exhaust passage 2 between the inner lid 50 and the upper lid 100 (see FIG. 3). The exhaust passage 2 is a passage connecting the storage chamber 19 of the battery case 17 and an exhaust port 201 (see FIG. 1) provided in the cover member 45. The exhaust passage 2 guides gas generated in the cell chambers 21 to 26 of the battery case 17 to the exhaust port 201 and discharges the gas to the outside of the lead storage battery 1. The exhaust passage 2 includes a plurality of individual passages 81 to 86 and a common passage 9.

  In the present embodiment, the lid member 45 includes six individual passages 81 to 86. The individual passages 81 to 86 communicate with the six cell chambers 21 to 26, respectively.

  The common passage 9 communicates with the individual passages 81 to 86 and is connected to the exhaust port 201. The common passage 9 includes seven passages 91 to 97.

  The individual passages 81 and 91 and the individual passages 86 and 96 are symmetrically arranged as shown in FIG. More specifically, the individual passages 81 and 91 and the individual passages 86 and 96 are formed by the virtual plane 15 (the normal line is parallel to the left-right direction 13 and passes through the center of the lid member 45 in the left-right direction 13). (Plane). Similarly, the individual passages 82 and 92 and the individual passages 85 and 95 are symmetrical with respect to the virtual plane 15. The individual passages 83 and 93 and the individual passages 84 and 94 are symmetrical with respect to the virtual plane 15. The shapes of the individual passages 82 and 92 and the shapes of the individual passages 83 and 93 are substantially the same.

3. Individual passage

  The individual passages 81 to 86 are provided for each of the cell chambers 21 to 26 of the battery case 17 between the inner lid 50 and the upper lid 100 (see FIG. 3). The individual passages 81 to 86 communicate with the common passage 9 and have a function of flowing the gas flowing out of the cell chambers 21 to 26 to the common passage 9. The individual passages 81 to 86 include the exhaust portion 6 and a passage formed by lower passage walls 61 to 66 (see FIGS. 8 and 9) and upper passage walls 111 to 116 described below. The exhaust part 6 is substantially cylindrical and serves as a gas passage.

  The exhaust unit 6 will be described in detail. As shown in FIG. 4, the lower surface portion 56 of the inner lid 50 includes six lower cylindrical portions 78 arranged in the left-right direction 13. As shown in FIGS. 4 and 8, the lower cylindrical portion 78 has a rectangular cylindrical shape, and includes a part of the lower outer peripheral wall 70, a part of the lower partition 71, and two lower peripheral walls 72 and 73 ( FIG. 8). The two lower peripheral walls 72 and 73 project upward from the upper surface of the upper surface wall 57 of the low surface portion 56.

  As shown in FIG. 4, the upper surface wall 57 of the lower surface portion 56 includes six communication holes 74 arranged in the left-right direction 13. Each communication hole 74 is arranged inside each lower cylindrical portion 78. Each communication hole 74 penetrates the upper surface wall 57 of the lower surface portion 56 in the vertical direction 11 (a direction perpendicular to the paper surface in FIGS. 4 and 8), and communicates with each of the cell chambers 21 to 26 of the battery case 17.

  As shown in FIG. 7, the lid main body 101 of the upper lid 100 includes six upper cylindrical portions 118 arranged in the left-right direction 13. The upper cylindrical portion 118 has a rectangular cylindrical shape as shown in FIGS. The upper cylindrical portion 118 includes a part of the upper outer peripheral wall 107, a part of the upper partition wall 108, and two upper peripheral walls 109 and 110. The two upper peripheral walls 109 and 110 project downward from the lower surface of the upper surface wall 102 of the lid main body 101.

  Each lower cylinder portion 78 (see FIG. 4) and each upper cylinder portion 118 vertically overlap to form one exhaust unit 6. The upper peripheral wall 109 (see FIG. 9) corresponds to the lower peripheral wall 72 (see FIG. 8), overlaps with the lower peripheral wall 72, and is joined by heat welding. On the other hand, the upper peripheral wall 110 (see FIG. 9) does not overlap with the lower peripheral wall 73 (see FIG. 8) and is located to the right of the lower peripheral wall 73. In the right end of the exhaust unit 6, the upper peripheral wall 110 is located to the left of the lower peripheral wall 73. As described above, the upper outer peripheral wall 107 and the upper partition 108 overlap with the corresponding lower outer peripheral wall 70 and the lower partition 71, and are joined by heat welding.

  Each exhaust unit 6 configured as described above communicates with each cell chamber 21 to 26 through each communication hole 74 as shown in FIGS. Therefore, the gas generated in each of the cell chambers 21 to 26 of the battery case 17 flows into each of the exhaust portions 6 through the communication holes 74 and is separated from the upper peripheral wall 110 and the lower peripheral wall along the left-right direction 13. 73, and flows toward the exhaust port 201 through the individual passages 81 to 86.

  Next, the passage formed by the lower passage walls 61 to 66 and the upper passage walls 111 to 116 will be specifically described. As shown in FIG. 8, the lower surface portion 56 of the inner lid 50 has a plurality of lower passage walls 61 to 66 for each of the cell chambers 21 to 26 of the battery case 17. The lower passage walls 61 to 66 project upward from the upper surface of the upper surface wall 57 of the low surface portion 56.

  The lower passage wall 61 is continuous with the lower peripheral wall 72 of the lower cylindrical portion 78, and the lower peripheral wall 72 is a wall extended to the left. The left end of the lower passage wall 61 is bent obliquely right and rearward in the vicinity of the lower partition wall 71 and extends to the vicinity of the lower outer peripheral wall 70.

  The lower passage wall 62 extends obliquely rightward and rearward from the lower partition wall 71. The right end of the lower passage wall 62 is bent rearward near the lower passage wall 65 and extends to the vicinity of the lower passage wall 61.

  The lower passage wall 63 extends rearward from the lower passage wall 62, and its tip is located near the lower passage wall 61.

  The lower passage wall 64 extends leftward from the lower partition wall 71, and extends obliquely leftward and backward from the middle. The distal end of the lower passage wall 64 is bent rearward near the left lower partition wall 71 and extends to the vicinity of the lower passage wall 62.

  The lower passage wall 65 extends rearward from the lower passage wall 64, and its tip is located near the lower passage wall 61.

  The lower passage wall 66 is a wall extending rightward from the lower partition 71, and its tip is located near the right lower partition 71.

  As shown in FIG. 8, the lower passage walls 61 to 66 are aggregates of walls having different directions. As described above, the lower passage walls 61 to 66 are connected to the other lower passage walls 61 to 66 and the lower partition wall 71, thereby forming a bent wall. Therefore, the paths of the individual passages 81 to 86 have a non-linear maze shape. That is, the lid member 45 has the lower passage walls 61 to 66 and forms bent individual passages 81 to 86.

  As shown in FIG. 9, the lid main body 101 of the upper lid 100 has upper passage walls 111 to 116. These upper passage walls 111 to 116 are provided for each of the cell chambers 21 to 26 of the battery case 17. The upper passage walls 111 to 116 protrude downward from the lower surface of the upper wall 102 of the lid body 101.

  The upper passage wall 111 extends leftward continuously to the upper peripheral wall 109 of the upper cylindrical portion 118. The left end of the upper passage wall 111 bends obliquely right and rearward in the vicinity of the upper partition 108 and extends to the vicinity of the upper outer peripheral wall 107.

  The upper passage wall 112 extends obliquely rightward and rearward from the upper partition wall 108. The right end of the upper passage wall 112 is bent rearward in the vicinity of the upper passage wall 115 and extends to the vicinity of the upper passage wall 111.

  The upper passage wall 113 extends rearward from the upper passage wall 112, and its tip is located near the upper passage wall 111.

  The upper passage wall 114 extends leftward from the upper partition wall 108, and extends obliquely leftward rearward from the middle. The tip of the upper passage wall 114 is bent rearward near the left upper partition wall 108 and extends to the vicinity of the upper passage wall 112.

  The upper passage wall 115 extends rearward from the upper passage wall 114, and its tip is located near the upper passage wall 111.

  The upper passage wall 116 is a wall extending rightward from the upper partition 108, and its tip is located near the right upper partition 108.

  As shown in FIG. 9, the upper passage walls 111 to 116 are aggregates of walls having different directions. The upper passage walls 111 to 116 are connected to the other upper passage walls 111 to 116 and the upper partition 108, and form a bent wall. Thus, the paths of the individual passages 81 to 86 have a non-linear maze shape. That is, the lid member 45 has upper passage walls 111 to 116 and forms bent individual passages 81 to 86.

  The upper passage walls 111 to 116 and the lower passage walls 61 to 66 are vertically overlapped to form a passage wall. The upper passage walls 111 to 116 correspond to the lower passage walls 61 to 66, overlap with the corresponding lower passage walls 61 to 66, and are joined by heat welding. Individual passages 81 to 86 are provided between the thus formed passage wall, the lower partition wall 71, the upper partition wall 108, the lower outer peripheral wall 70, and the upper outer peripheral wall 107.

  As shown in FIG. 8, the paths of the individual passages 82 and 83 extend leftward between the lower passage wall 61 and the lower outer peripheral wall 70 with the communication hole 74 as a starting point, and extend from the lower passage wall 61 to the lower passage. It extends downward between the side partition walls 71. Next, this path extends rightward between the lower passage wall 61 and the lower passage wall 62 and extends downward between the lower passage wall 62 and the lower passage wall 65. Next, this path extends leftward between the lower passage wall 62 and the lower passage wall 64 and extends downward between the lower passage wall 64 and the lower partition wall 71. This path extends rightward between the lower passage wall 64 and the lower passage wall 66, reaches a gap between the lower passage wall 66 and the lower partition wall 71, and is an end point. At this end point, the individual passages 82 and 83 merge with the common passage 9.

  As shown in FIG. 8, the path of the individual passage 81 extends rightward between the lower passage wall 61 and the lower outer peripheral wall 70 with the communication hole 74 as a starting point, and the lower passage wall 61 and the lower outer periphery. It extends downward between the wall 70. Next, this path extends leftward between the lower passage wall 61 and the lower passage wall 62 and extends downward between the lower passage wall 62 and the lower passage wall 65. Next, this path extends rightward between the lower passage wall 62 and the lower passage wall 64 and extends downward between the lower passage wall 64 and the lower tubular portion 79. Then, this route reaches a gap between the lower passage wall 64 and the lower tubular portion 79, and is an end point. At this end point, the individual passage 81 merges with the common passage 9.

  Up to this point, the above-described path has been described on the side of the inner lid 50 shown in FIG. 8, but the same configuration is also applied to the side of the upper lid 100 shown in FIG. The individual passages 84 to 86 are symmetrical with respect to the individual passages 81 to 83 with respect to the imaginary plane 15, and therefore description thereof is omitted.

4. Common passage

  The common passage 9 is provided between the inner lid 50 and the upper lid 100. The common passage 9 collects gas flowing from the six individual passages 81 to 86 and discharges the gas from the exhaust port 201 to the outside of the lead storage battery 1. In the present embodiment, as shown in FIGS. 4 and 7, the common passage 9 includes seven passages 91 to 97. The intermediate filter section 4 is provided between the passages 93 and 94 and the passage 97 (see FIG. 7). That is, the intermediate filter section 4 is arranged in the middle of the common passage 9. A collective exhaust unit 3 is provided at an end of the passage 97 on the exhaust port 201 side.

5. Collective exhaust

  The collective exhaust unit 3 is provided between the inner lid 50 and the upper lid 100, and has a function of collectively exhausting the gas generated in the cell chambers 21 to 26 to the outside of the lead storage battery 1. In the present embodiment, the collective exhaust unit 3 is disposed at the right end of the lid member 45 as shown in FIG. The collective exhaust unit 3 may be arranged at another position, for example, at the left end of the lid member 45.

  As shown in FIG. 8, the lower surface portion 56 of the inner lid 50 includes a lower cylindrical portion 79. The lower cylindrical portion 79 protrudes upward from the upper surface of the upper surface wall 57 of the lower surface portion 56. The lower tubular portion 79 is continuous with the lower tubular wall 69 and the lower outer peripheral wall 70 at the right end.

  As shown in FIG. 9, the lid main body 101 of the upper lid 100 includes an upper tubular portion 119 and an exhaust duct 200. The upper cylindrical portion 119 protrudes downward from the lower surface of the upper wall 102 of the lid main body 101. The upper cylindrical portion 119 is continuous with the upper cylindrical wall 106 and the upper outer peripheral wall 107 at the right end. The left end of the exhaust duct 200 communicates with the space inside the upper cylinder 119. The right end of the exhaust duct 200 is connected to an exhaust port 201 formed on the right side surface of the upper lid 100.

  A filter 205 (corresponding to a “first filter” described in the claims) is housed in a space inside the upper cylindrical portion 119. The lower surface of the filter 205 is located higher than the lower surface of the upper tubular portion 119. The filter 205 suppresses the external spark from entering the inside of the lead storage battery 1. The filter 205 is a disk-shaped member and is, for example, a porous body having continuous pores. The porous body is, for example, a sintered body of ceramic particles such as alumina or resin particles such as polypropylene. The filter 205 has, for example, an average diameter of several tens to several hundreds μm.

  The upper cylinder portion 119 and the lower cylinder portion 79 are heat-welded in a state of being vertically overlapped to form the collective exhaust portion 3. The gas passing through the passage 97 flows into the space inside the lower cylinder 79 from the opening in front of the lower cylinder 79 (see FIG. 8), and reaches the filter 205. The gas that has passed through the filter 205 flows into the exhaust duct 200 from the space above the upper cylindrical portion 119, and is discharged to the outside of the lead storage battery 1 through the exhaust port 201.

6. Intermediate filter section

  The intermediate filter unit 4 is provided between the inner lid 50 and the upper lid 100. In the present embodiment, as shown in FIG. 7, the intermediate filter unit 4 is disposed at the center of the cover member 45 in the left-right direction 13. In the present embodiment, the intermediate filter unit 4 is disposed at the center in the left-right direction 13. Specifically, the center of the intermediate filter section 4 is arranged on the virtual plane 15. Note that the intermediate filter section 4 only needs to be disposed in the above-mentioned central portion, and the central portion means a predetermined region E set in the left-right direction 13 with respect to the virtual plane 15. The predetermined area E is an area satisfying | E | ≦ 0.25A with respect to the length A of the upper cover 100 in the left-right direction 13. | E | ≦ 0.2 is more preferable, and | E | ≦ 0.1 is more preferable. In the present embodiment, E = 0.

  As shown in FIGS. 8, 10 and 11, the lower surface portion 56 of the inner lid 50 includes a transverse wall 75. The transverse wall 75 protrudes upward from the upper surface of the upper surface wall 57 of the low surface portion 56. The cross wall 75 is connected to the left lower cylindrical wall 69 and the right lower cylindrical wall 69. That is, the crossing wall 75 is a wall that crosses the common passage 9.

  As shown in FIGS. 9, 10, and 11, the lid main body 101 of the upper lid 100 includes an upper cylindrical portion 211. The upper cylindrical portion 211 protrudes downward from the lower surface of the upper wall 102 of the lid main body 101. The upper cylinder part 211 is connected to the right upper cylinder wall 106, the left upper cylinder wall 106, and the upper partition 108.

  A disk-shaped filter 212 (corresponding to a “second filter” described in the claims) is housed in a space inside the upper cylindrical portion 211. The center of the filter 212 coincides with the center of the intermediate filter section 4. The lower surface of the filter 212 is located above the lower surface of the upper tubular part 211. The filter 212 is, for example, a porous body having continuous pores. The porous body is, for example, a sintered body of ceramic particles such as alumina or resin particles such as polypropylene. The filter 212 has, for example, an average diameter of several tens to several hundreds μm. In this embodiment, a filter having the same shape, material, and characteristics as the filter 205 is used as the filter 212.

  As shown in FIG. 11, the cross wall 75 abuts on the lower surface of the filter 212 from below. Above the filter 212, there is a space 16 surrounded by the upper cylindrical portion 211, the lid body 101, and the filter 212. The gas passing through the passages 93 and 94 flows below the upper cylindrical portion 211, is guided by the transverse wall 75, passes through the filter 212, and flows into the space 16 above the filter 212. The gas that has flowed into the space 16 passes through the filter 212 again, passes between the upper cylindrical portion 211 and the cross wall 75, and flows out of the front of the cross wall 75 to the passage 97. That is, in the intermediate filter section 4 of the present embodiment, the gas that has flowed into the upper cylindrical section 211 from the passages 93 and 94 passes through the filter 212 twice.

  As described above, the intermediate filter unit 4 is disposed between the passage 93 and the passage 94 and the passage 97 (see FIG. 9), and the collective exhaust unit 3 is an end of the passage 97 on the exhaust port 201 side (this embodiment). (The end in the form). That is, the intermediate filter section 4 and the collective exhaust section 3 are separated from each other along the passage 97. That is, the filter 212 is separated from the filter 205 by a predetermined distance along the path of the passage 97. This predetermined distance is the length of the path of the passage 97 and is set to, for example, 115 mm.

  As shown in FIG. 7, the passages 91 to 97 have a complicated structure. These are a lower connecting wall 76 (see FIG. 8), an upper connecting wall 117 (see FIG. 9), a lower cylindrical wall 69 (see FIG. 8), a lower outer peripheral wall 70 (see FIG. 8), and a lower partition 71. (See FIG. 8), lower tubular portion 79 (see FIG. 8), upper tubular wall 106 (see FIG. 9), upper outer peripheral wall 107 (see FIG. 9), upper partition 108 (see FIG. 9), and upper tubular portion 119. (See FIG. 9).

  As shown in FIG. 8, the lower surface portion 56 of the inner lid 50 includes a lower connecting wall 76. The lower connecting wall 76 protrudes upward from the upper surface of the upper surface wall 57 of the low surface portion 56. The lower connection wall 76 is connected to the right lower cylinder wall 69, the left lower cylinder wall 69, and the lower partition wall 71.

  As shown in FIG. 9, the lid main body 101 of the upper lid 100 includes an upper connecting wall 117. The upper connecting wall 117 protrudes downward from the lower surface of the upper wall 102 of the lid main body 101. The upper connection wall 117 is connected to the right upper cylinder wall 106 and the left upper cylinder wall 106.

  The upper connecting wall 117 and the lower connecting wall 76 (see FIG. 8) are vertically overlapped to form a passage wall. More specifically, the upper connecting wall 117 corresponds to the lower connecting wall 76, and overlaps the corresponding lower connecting wall 76 and is joined by heat welding. The passage wall thus formed, the lower cylindrical wall 69, the lower outer peripheral wall 70, the lower partition 71, the lower cylindrical part 79, the upper cylindrical wall 106, the upper outer peripheral wall 107, the upper partition 108, and the upper cylindrical part Between 119, passages 91 to 97 are formed.

  As shown in FIG. 9, the path of the passage 91 starts from the end point of the individual passage 81 (the gap between the upper passage wall 114 and the upper cylinder part 119), and the upper cylinder wall 119, the upper cylinder wall 106, and the upper passage wall 106. It extends diagonally forward to the left between 114 and the upper partition 108. Further, the path 91 extends downward from the gap between the upper partition wall 108 and the upper connecting wall 117 through the space between the upper partition wall 108 and the upper cylindrical wall 106, and ends at the end point of the individual passage 82 (the upper passage wall 116 and the upper (A gap with the partition wall 108).

  The path of the passage 92 starts from an end point of the individual passage 82 and the passage 91 (a gap between the upper passage wall 116 and the upper partition wall 108), and extends between the upper passage wall 116 and the upper partition wall 108 and the upper cylindrical wall 106. Extend towards. Further, the path 92 extends downward from the gap between the upper partition wall 108 and the upper connecting wall 117 through the space between the upper partition wall 108 and the upper cylindrical wall 106, and ends at the end point of the individual passage 83 (the upper passage wall 116 and the upper (A gap with the partition wall 108).

  The path of the passage 93 extends to the left between the upper passage wall 116 and the upper cylindrical wall 106 starting from the end point of the individual passage 83 and the passage 92 (the gap between the upper passage wall 116 and the upper partition wall 108). Further, the path 93 advances diagonally forward left between the upper partition wall 108 and the upper cylindrical wall 106 to reach the intermediate filter section 4.

  The path of the passage 97 extends rightward between the upper cylindrical wall 106 and the upper connecting wall 117 and the upper outer peripheral wall 107 starting from the intermediate filter section 4, and further extends rearward to the collective exhaust section 3. .

  With respect to the passages 91 to 93 and 97, the structure on the side of the upper lid 100 (see FIG. 9) has been described, but the same applies to the side of the inner lid 50 (see FIG. 8). The passages 94 to 96 are symmetrical with respect to the imaginary plane 15 with respect to the passages 91 to 93, and therefore description thereof is omitted.

[About exhaust]

  The manner in which the gas generated in each of the cell chambers 21 to 26 is exhausted through the exhaust passage 2 will be described.

  The gas generated in the cell chamber 21 (see FIG. 2) located at the right end in the left-right direction 13 passes through the individual passage 81 and the passages 91, 92 and 93 as shown in FIG. As described above, the air is discharged from the exhaust port 201 to the outside of the lead-acid battery 1 through the intermediate filter unit 4, the passage 97, and the collective exhaust unit 3. The gas generated in the cell chamber 22 located adjacent to the left of the cell chamber 21 (see FIG. 2) passes through the individual passage 82 and the passages 92 and 93 as shown in FIG. 4, and as shown in FIG. Then, the air is discharged from the exhaust port 201 to the outside of the lead-acid battery 1 through the intermediate filter unit 4, the passage 97, and the collective exhaust unit 3. The gas generated in the cell chamber 23 located adjacent to the left of the cell chamber 22 (see FIG. 2) passes through the individual passage 83 and the passage 93 as shown in FIG. 4, and as shown in FIG. The exhaust gas is discharged from the exhaust port 201 to the outside of the lead-acid battery 1 through the intermediate filter unit 4, the passage 97, and the collective exhaust unit 3.

  The length (passage length) of the exhaust passage 2 from each of the cell chambers 21 to 26 to the intermediate filter unit 4 is as follows. As shown in FIG. 4, the passage length of the cell chamber 21 is the sum of the lengths of the individual passage 81, the passage 91, the passage 92, and the passage 93. The passage length of the cell chamber 22 is the sum of the lengths of the individual passage 82, the passage 92, and the passage 93. Therefore, the passage length of the cell chamber 21 is longer than the passage length of the cell chamber 22. The passage length of the cell chamber 23 is the sum of the lengths of the individual passage 83 and the passage 93. Therefore, the passage length of the cell chamber 22 is longer than the passage length of the cell chamber 23.

  Similarly, gas generated in the cell chamber 26 (see FIG. 2) located at the left end in the left-right direction 13 passes through the individual passage 86 and the passages 96, 95, and 94 as shown in FIG. As shown by 9, the exhaust gas is discharged from the exhaust port 201 to the outside of the lead storage battery 1 through the intermediate filter section 4, the passage 97, and the collective exhaust section 3. The gas generated in the cell chamber 25 located adjacent to the right of the cell chamber 26 (see FIG. 2) passes through the individual passage 85 and the passages 95 and 94 as shown in FIG. 4, and as shown in FIG. Then, the air is discharged from the exhaust port 201 to the outside of the lead-acid battery 1 through the intermediate filter unit 4, the passage 97, and the collective exhaust unit 3. The gas generated in the cell chamber 24 located adjacent to the right of the cell chamber 25 (see FIG. 2) passes through the individual passage 84 and the passage 94 as shown in FIG. 4, and as shown in FIG. The exhaust gas is discharged from the exhaust port 201 to the outside of the lead-acid battery 1 through the intermediate filter unit 4, the passage 97, and the collective exhaust unit 3.

  The passage length of the cell chamber 26 is the sum of the lengths of the individual passage 86, the passage 96, the passage 95, and the passage 94. The passage length of the cell chamber 25 is the sum of the lengths of the individual passage 85, the passage 95, and the passage 94. Therefore, the passage length of the cell chamber 26 is longer than the passage length of the cell chamber 25. The passage length of the cell chamber 24 is the sum of the lengths of the individual passages 84 and the passages 94. Therefore, the passage length of the cell chamber 25 is longer than the passage length of the cell chamber 24.

  The cell chamber 21 and the cell chamber 26 are examples of a cell chamber located at an end in the left-right direction 13. The cell chambers 22, 23, 24, and 25 are examples of the remaining cell chambers.

  As shown in FIG. 4, the lower surface portion 56 of the inner lid 50 includes six return holes 77 arranged in the left-right direction 13. Each return hole 77 is located in a region surrounded by the lower outer peripheral wall 70, the lower partition wall 71, the lower peripheral wall 73, and the lower passage wall 61. Each return hole 77 penetrates the upper surface wall 57 of the lower surface portion 56 in the up-down direction 11 (a direction perpendicular to the paper surface in the figure) and communicates with each cell chamber 21 to 26 of the battery case 17.

  The low surface portion 56 forms the bottom surface of the individual passages 81 to 86. The upper surface of the upper surface wall 57 of the lower surface portion 56 is inclined so as to be lower in the up-down direction 11 as being closer to the return hole 77. As a result, water vapor (water droplets) contained in the gas discharged from the cell chambers 21 to 26 and liquid droplets such as an electrolytic solution return to the cell chambers 21 to 26 through the return holes 77. That is, water vapor contained in the gas generated in the cell chambers 21 to 26 is condensed in the individual passages 81 to 86 when the gas passes through the individual passages 81 to 86. The condensed droplet flows along the upper surface (inclined surface) of the upper surface wall 57 toward the return hole 77. Droplets such as water vapor contained in the above-mentioned gas return to each of the cell chambers 21 to 26.

[Modification]

  In the intermediate filter unit 4 (see FIG. 9), the filter 212 may be arranged in a mode different from that of the above embodiment. In the following, the same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  As shown in FIGS. 12 and 13, the lower surface portion 56 of the inner lid 50 includes lower transverse walls 311 and 312. The lower transverse walls 311 and 312 protrude upward from the upper surface of the upper surface wall 57 of the low surface portion 56. The lower transverse walls 311 and 312 are connected to the left lower cylindrical wall 69 and the right lower cylindrical wall 69.

  The lid body 101 of the upper lid 100 includes upper transverse walls 321 and 322. The upper transverse walls 321 and 322 project downward from the lower surface of the upper wall 102 of the lid main body 101. The upper cross walls 321 and 322 are connected to the upper cylinder wall 106 on the left and the upper cylinder wall 106 on the right.

  The upper cross walls 321 and 322 correspond to the lower cross walls 311, 312. As shown in FIG. 13, the lower surfaces of the upper transverse walls 321 and 322 are located higher than the lower surfaces of the upper cylindrical wall 106, the upper partition 108, and the like. The upper cross walls 321 and 322 are separated from the lower cross walls 311 and 312 along the up-down direction 11.

  In the present modification, as shown in FIG. 13, the filter 212 is disposed between the inner lid 50 and the upper lid 100 in a posture in which the thickness direction coincides with the front-back direction 12. The lower end of the filter 212 is located between the lower cross wall 311 and the lower cross wall 312. The upper end of the filter 212 is located between the upper cross wall 321 and the upper cross wall 322. The gas passing through the passages 93 and 94 passes between the lower transverse wall 311 and the upper transverse wall 321 and passes through the filter 212 from back to front. The gas that has passed through the filter 212 passes between the lower transverse wall 312 and the upper transverse wall 322 and flows out to the passage 97. That is, in the intermediate filter section 4 according to this modification, the gas passing through the passages 93 and 94 passes through the filter 212 once.

[Example]

  A test was performed under the following conditions in which the lead-acid battery 1 was continuously vibrated for a predetermined time while performing constant-voltage charging in a high-temperature environment, and the amount of decrease in the electrolyte was measured.

(1) The following four types of lead storage batteries 1 in which the arrangement of the filters 205 and 212 in the collective exhaust unit 3 and the intermediate filter unit 4 are different are tested.

  Embodiment 1: One filter 205 is disposed in the collective exhaust unit 3. The form of the intermediate filter unit 4 is the form of the above-described modification. One filter 212 is arranged in the intermediate filter unit 4. The distance between the filter 205 and the filter 212 is 115 mm.

  Embodiment 2: One filter 205 is arranged in the collective exhaust unit 3. The form of the intermediate filter unit 4 is the form of the above embodiment. One filter 212 is arranged in the intermediate filter unit 4. The distance between the filter 205 and the filter 212 is 115 mm.

  Comparative Example 1: One filter 205 is arranged in the collective exhaust unit 3. No filter is arranged in the intermediate filter unit 4.

  Comparative Example 2: Two filters 205 are arranged on the collective exhaust unit 3 in an overlapping manner. The two filters 205 are in contact. No filter is arranged in the intermediate filter unit 4.

  The ventilation resistance of each of the filters 205 and 212 used in the test is 0.3 KPa. The ventilation resistance of the filter is measured as follows. The filter is placed inside the cylinder, air is supplied from one opening of the cylinder at a flow rate of 1 liter / min, and the pressure of the air before passing through the filter is measured. The value obtained by subtracting the atmospheric pressure from the measured pressure is defined as the ventilation resistance of the filter.

(2) The ambient temperature is 60 ° C., the frequency of vibration is 10 Hz to 55 Hz, the acceleration is 9.8 m / s ² , the vertical direction, and the test time is 120 hours.

(3) The difference between the weight of the lead storage battery 1 before the start of the test and the weight of the lead storage battery 1 after the end of the test is divided by the test time (120 hours) to determine the amount of liquid reduction per unit time.

  As shown in Table 1, the test results were as follows: the reduced amount of Example 1 was 0.42 g / h, the reduced amount of Example 2 was 0.37 g / h, and the reduced amount of Comparative Example 1 was 0.54 g. / H, the liquid reduction amount of Comparative Example 2 was 0.47 g / h.

  Comparative Example 2 has a smaller liquid reduction amount than Comparative Example 1. It is considered that this is because the two filters 205 are overlapped in the collective exhaust unit 3 of Comparative Example 2, and the ventilation resistance of the collective exhaust unit 3 of Comparative Example 2 is twice that of Comparative Example 1. .

  Example 1 has a smaller liquid reduction amount than Comparative Example 2. The number of filters arranged in the exhaust passage 2 is the same (two) in Example 1 and Comparative Example 2. Therefore, the decrease in the amount of liquid reduction in Example 1 is not caused by the increase in the ventilation resistance. Here, in Comparative Example 2, two filters are arranged in an overlapping manner, whereas in Example 1, two filters are arranged in the collective exhaust unit 3 and the intermediate filter unit 4 and are separated from each other. It is presumed that the decrease in the amount of liquid reduction in the first embodiment is due to the separation of the filter 205 of the collective exhaust unit 3 and the filter 212 of the intermediate filter unit 4.

  Example 2 has a smaller amount of liquid reduction than Example 1. The intermediate filter unit 4 according to the first embodiment is in the form of the above-described modification. In the intermediate filter unit 4 of the modified example, as shown in FIG. 13, the gas flowing from the passages 93 and 94 passes through the filter 212 once and flows out to the passage 97. On the other hand, the intermediate filter unit 4 of the second embodiment is in the form of the above-described embodiment. In the intermediate filter unit 4 of the embodiment, as shown in FIG. 11, the gas flowing from the passages 93 and 94 passes through the filter 212 twice and flows out to the passage 97. Therefore, the intermediate filter section 4 of the second embodiment has a higher airflow resistance than the intermediate filter section 4 of the first embodiment. Thus, it is considered that the amount of liquid reduction in Example 2 was smaller than that in Example 1.

  From the test described above, by providing the exhaust passage 2 with the filter 205 arranged at the end on the exhaust port 201 side and the filter 212 arranged at a position separated from the filter 205 and in the middle of the exhaust passage 2, It was confirmed that the decrease could be significantly suppressed. In addition, it was confirmed that the use of the embodiment of the intermediate filter unit 4 can suppress the decrease in the electrolytic solution. In particular, since the filter 212 is disposed at the center of the common passage 9, the distance between each of the cell chambers 21 to 26 and the filter 212 is the largest between the cell chambers 21 and 26 and the filter 212, The cell chambers 22 and 25 and the cell chambers 23 and 24 on the inner side of 7 become smaller in this order. That is, the distance is larger in the cell chambers 21 to 26 disposed outside the inside of the battery case 17 than in the inside. This difference in distance causes a volume difference in each space (space along the exhaust passage 2) from each of the cell chambers 21 to 26 to the filter 212. For this reason, the behavior of the water vapor and the electrolyte 14 (electrolyte mist) in each of the above-mentioned spaces changes for each of the cell chambers 21 to 26, and the imbalance of humidity, pressure, and the like among the cell chambers 21 to 26 is reduced. You. That is, the difference in the amount of decrease in the amount of the electrolytic solution 14 among the cell chambers 21 to 26 is reduced. Even when the filter 212 is set in a region where | E | ≦ 0.25A is satisfied with respect to the length A of the upper cover 100 in the left-right direction 13 when the predetermined region E set in the left-right direction 13 is used, There is an effect of alleviating the difference in the reduction amount of the electrolyte solution 14 between 21 and 26.

[Other Modifications]

  In the above embodiment, as shown in FIG. 7, the intermediate filter unit 4 is arranged at a position where the passage 93 and the passage 94 meet. The intermediate filter unit 4 may be arranged at another position as long as it is in the middle of the exhaust passage 2. Further, two or more intermediate filter units 4 may be arranged.

  In the above embodiment, as shown in FIG. 11, the space 16 exists above the filter 212 in the intermediate filter unit 4. This space 16 does not exist, and the upper surface of the filter 212 may be in contact with the upper surface wall 102 of the lid main body 101. In this embodiment, the gas passing through the passages 93 and 94 flows below the upper cylindrical portion 211, is guided to the transverse wall 75, and passes through the inside of the filter 212. The gas that has passed through the filter 212 passes between the upper cylindrical portion 211 and the cross wall 75 and flows out of the front of the cross wall 75 to the passage 97.

  The structure of the collective exhaust unit 3 may be the same as the structure of the intermediate filter unit 4 described in the above embodiment.

The present invention can be implemented in the following forms.
(1)
A battery case having an opening, a plurality of cell chambers communicating with the opening and containing the electrolyte and the electrode group are partitioned along a predetermined direction,
A lid member that has an exhaust port and seals the opening;
The lid member,
An inner lid fixed to the upper part of the battery case,
An upper lid fixed to the upper part of the inner lid,
An exhaust passage formed between the upper lid and the inner lid, and having a plurality of individual passages communicating with each of the cell chambers and a common passage communicating with the individual passages and connecting to the exhaust port;
A first filter disposed at an exhaust port side end of the exhaust passage;
A lead-acid battery including a second filter disposed in the middle of the common passage and in the center of the lid member in the predetermined direction.

(2)
The length of the individual passage from the cell chamber located at the end in the predetermined direction to the second filter is set longer than the length of the individual passage from the remaining cell chamber to the second filter ( The lead storage battery according to 1).

DESCRIPTION OF SYMBOLS 1 ... Lead storage battery 2 ... Exhaust passage 9 ... Common passage 14 ... Electrolyte 17 ... Battery case 18 ... Openings 21-26 ... Cell room 30 ... Electrode group 45 ... lid member 50 ... middle lid 51 ... lid plates 81 to 86 ... individual passage 100 ... upper lid 201 ... exhaust port 205 ... filter (first filter)
212 ... filter (second filter)

Claims (2)

A battery case having an opening, a plurality of cell chambers communicating with the opening and containing the electrolyte and the electrode group are partitioned along a predetermined direction,
A lid member that has an exhaust port and seals the opening;
The lid member,
An inner lid fixed to the upper part of the battery case,
An upper lid fixed to the upper part of the inner lid,
An exhaust passage formed between the upper lid and the inner lid, and having a plurality of individual passages communicating with each of the cell chambers and a common passage communicating with the individual passages and connecting to the exhaust port;
A first filter disposed at an exhaust port side end of the exhaust passage;
A lead-acid battery including a second filter disposed in the middle of the common passage and in the center of the lid member in the predetermined direction. The length of the individual passage from the cell chamber located at the end in the predetermined direction to the second filter is set longer than the length of the individual passage from the remaining cell chamber to the second filter. Item 7. The lead storage battery according to Item 1.

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