Lead-acid battery

Abstract

This lead storage battery comprises: a housing including a battery case with one end open, and a lid that seals the opening of the battery case; and an electrode plate group including, in the battery case, a plurality of positive electrode plates and a plurality of negative electrode plates arranged in an alternating manner with a separator therebetween. Each positive electrode plate includes a first foot part that protrudes toward the bottom surface of the battery case. Each negative electrode plate includes a second foot part that protrudes toward the bottom surface of the battery case. The first foot parts and the second foot parts are disposed at different positions when viewed from the arrangement direction of the electrode plate group. When viewed from a direction perpendicular to the bottom surface of the battery case, ribs are formed on the bottom surface. The ribs: extend from an edge of a specific region sandwiched between a row consisting of a plurality of the first foot parts and a row consisting of a plurality of the second foot parts protruding from the electrode plate group; and also divide at least a portion of the specific region into a plurality of sections.

Description

[Technical field]

[0001] The technology disclosed in this specification relates to lead-acid batteries. [Background technology]

[0002] Lead-acid batteries are used, for example, as backup power sources for communication base stations. The lead-acid battery includes a housing and a plate group housed in the housing. The housing has a battery case with one end open and a lid that seals the opening of the battery case. The plate group includes a plurality of positive electrode plates and a plurality of negative electrode plates that are arranged alternately in the battery case with a separator interposed therebetween. Each positive electrode plate has a first foot that protrudes toward the bottom surface of the battery case, and each negative electrode plate has a second foot that protrudes toward the bottom surface of the battery case. The first foot and the second foot are arranged at different positions when viewed from the arrangement direction of the plate group.

[0003] In conventional lead-acid batteries, a plurality of ribs (called "saddles") extending in the arrangement direction are formed on the bottom surface of the battery case, and a first leg protruding from a plurality of positive electrode plates is disposed on one rib, and a second leg protruding from a plurality of negative electrode plates is disposed on the other rib (see, for example, Patent Document 1). In such a configuration, the ribs form a space between the bottom surface of the battery case and the plate group, so that, for example, an expanded plate group is prevented from directly hitting the bottom surface of the battery case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-297414 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, some lead-acid batteries are charged in a vertically placed state in which the electrode plates in the casing are arranged horizontally, and then used in a horizontally placed state in which the electrode plates in the casing are arranged vertically after the charging. In such a lead-acid battery used in a horizontally placed state, for example, active material that falls off the electrodes during charging may cause a short circuit between the positive and negative electrodes. Specifically, when the lead-acid battery is placed vertically, the fallen active material may fall between the electrodes and accumulate on the bottom of the battery case. When the lead-acid battery is then placed horizontally, the active material that has accumulated on the bottom of the battery case is collected along the rib at one location on one side (lower side) in the arrangement direction of the electrode groups. As a result, the first leg of the positive electrode plate and the second leg of the negative electrode plate are electrically connected to each other through the active material that has been collected at one location, causing a short circuit.

[0006] This specification discloses a technique capable of suppressing a short circuit between a positive electrode plate and a negative electrode plate caused by fallen active material. [Means for solving the problem]

[0007] The lead-acid battery disclosed in this specification includes a housing having a battery case with an opening at one end and a lid for sealing the opening of the battery case, and a plate group having a plurality of positive and negative plates arranged alternately in the battery case with a separator interposed therebetween. Each of the positive plates has a first foot protruding toward the bottom surface of the battery case, and each of the negative plates has a second foot protruding toward the bottom surface of the battery case. The first foot and the second foot are arranged at different positions when viewed from the arrangement direction of the plate group. The bottom surface of the battery case has a rib extending from an end of a specific region sandwiched between a row of the first feet protruding from the plate group and a row of the second feet when viewed from a direction perpendicular to the bottom surface, and dividing at least a part of the specific region into multiple parts. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the external configuration (in a horizontally placed state) of a lead-acid battery 100 according to a first embodiment. [Diagram 2]2 is an explanatory diagram showing a bottom configuration of a battery case 102 of the lead-acid battery 100 in the first embodiment. FIG. [Diagram 3] 1 is an explanatory diagram showing a bottom configuration of a battery case 102x of a lead-acid battery 100x in a comparative example. FIG. [Figure 4] 10 is an explanatory diagram showing a bottom configuration of a battery case 102a of a lead-acid battery 100a in a second embodiment. FIG. [Diagram 5] 13 is an explanatory diagram showing the bottom configuration of a battery case 102b of a lead-acid battery 100b in the third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The technology disclosed in this specification can be realized in the following forms.

[0010] (1) A lead-acid battery disclosed in the present specification is a lead-acid battery comprising: a housing having a container having an opening at one end and a lid that seals the opening of the container; and a plate group having a plurality of positive plates and a plurality of negative plates that are arranged alternately in the container with separators interposed therebetween, each of the positive plates having a first foot that protrudes toward a bottom surface of the container, and each of the negative plates having a second foot that protrudes toward the bottom surface of the container, the first foot and the second foot being disposed at different positions from each other when viewed from the arrangement direction of the plate group, and a rib is formed on the bottom surface of the container, the rib extending from an end of a specific region sandwiched between a row of the first feet and a row of the second feet that protrude from the plate group when viewed from a direction perpendicular to the bottom surface, and dividing at least a portion of the specific region into multiple parts.

[0011] In this lead-acid battery, a rib is formed on the bottom surface. When viewed from a direction perpendicular to the bottom surface of the battery case, the rib is formed to divide at least a part of a specific region sandwiched between a row of a plurality of first legs protruding from the electrode plate group and a row of a plurality of second legs. As a result, when the lead-acid battery is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case is dispersed into a plurality of regions divided by the rib. As a result, in this lead-acid battery, compared to a conventional configuration not provided with a rib, when the lead-acid battery is changed from a vertically placed state to a horizontally placed state, it is possible to prevent the active material accumulated on the bottom surface of the battery case from gathering in one place and causing a short circuit between the first leg of the positive plate and the second leg of the negative plate. This short circuit prevention effect is greater in a valve-regulated lead-acid battery that does not have a flowable electrolyte than in a flooded lead-acid battery, because the active material accumulated on the bottom surface of the battery case is difficult to agitate.

[0012] (2) In the lead-acid battery, the rib may include a first rib that divides the specific region into multiple regions in the arrangement direction of the electrode plate pack. According to this lead-acid battery, when the lead-acid battery is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case is dispersed into multiple regions divided vertically by the first rib. This makes it possible to prevent the active material accumulated on the bottom surface of the battery case from gathering in one place and causing a short circuit between the first foot of the positive plate and the second foot of the negative plate.

[0013] (3) In the lead-acid battery, the first rib may be configured to be spaced apart from at least one of a pair of side walls of the battery case that are substantially parallel to the arrangement direction of the electrode plate pack. In this lead-acid battery, the difference in rigidity between the side walls and the bottom of the battery case is smaller than in a configuration in which the first rib is in contact with both of the pair of side walls. Therefore, for example, when the lead-acid battery is deformed due to expansion or contraction, stress concentration at the boundary between the side walls and the bottom of the battery case and damage to the battery case can be suppressed.

[0014] (4) In the lead-acid battery, the rib may include a second rib that divides the specific region into multiple regions in a direction substantially perpendicular to the arrangement direction of the electrode plate group. According to this lead-acid battery, when the lead-acid battery is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case is dispersed into multiple regions divided into left and right by the second rib. This makes it possible to prevent the active material accumulated on the bottom surface of the battery case from gathering in one place and causing a short circuit between the first foot of the positive plate and the second foot of the negative plate.

[0015] (5) In the lead-acid battery, the second rib may extend from one of a pair of side walls of the battery case that are substantially perpendicular to the arrangement direction of the electrode plate pack, and be spaced apart from the other side wall. This lead-acid battery has a smaller difference in rigidity between the side walls and the bottom of the battery case than a configuration in which the second rib is in contact with both of the pair of side walls. Therefore, when the lead-acid battery is deformed due to expansion or contraction, for example, stress concentration at the boundary between the side wall and the bottom of the battery case and damage to the battery case can be suppressed.

[0016] (6) In the lead-acid battery, the rib may include a third rib that further divides one of the specific regions divided by the second rib into several parts in the arrangement direction of the electrode plate pack, and a fourth rib that further divides the other region divided by the second rib into several parts in the arrangement direction of the electrode plate pack, and a position of a joint between the second rib and the third rib and a position of a joint between the second rib and the fourth rib may be different from each other in the arrangement direction of the electrode plate pack. According to this lead-acid battery, when the lead-acid battery is changed from a vertically placed state to a horizontal state, the active material accumulated on the bottom surface of the battery case is dispersed into several regions divided left and right by the second rib, and further dispersed into several regions divided up and down by the third rib and the fourth rib. Furthermore, compared to a configuration in which the position of the joint between the second rib and the third rib and the position of the joint between the second rib and the fourth rib are the same in the arrangement direction of the electrode plate group, it is possible to more effectively prevent the active material accumulated on the bottom surface of the battery case from gathering in one place and causing a short circuit between the first foot of the positive electrode plate and the second foot of the negative electrode plate.

[0017] A. First embodiment: A-1. Overall configuration: (Configuration of lead-acid battery 100) FIG. 1 is a perspective view showing an external configuration of a lead-acid battery 100 in the first embodiment. In FIG. 1, the lead-acid battery 100 is arranged in a horizontally placed state. In FIG. 1, a part of a housing 101 described later that the lead-acid battery 100 has is cut away for convenience, and an internal structure is shown. In FIG. 1, mutually orthogonal XYZ axes are shown for specifying a direction. In this specification, for convenience, the positive direction of the Z axis is referred to as the "upward direction" and the negative direction of the Z axis is referred to as the "downward direction", but the lead-acid battery 100 may actually be installed in a position different from such an orientation. The same applies to FIG. 2 and subsequent figures. Hereinafter, the suffix "P" is added to the symbol of the positive electrode side component, and the suffix "N" is added to the symbol of the negative electrode side component.

[0018] The lead-acid battery 100 in this embodiment is arranged in a vertical position, for example, when being charged during manufacturing, and is used in a horizontal position (see FIG. 1) after being charged. For example, a plurality of lead-acid batteries 100 are arranged horizontally in a predetermined frame and used as a backup power source for a communication base station. The vertical position is a position in which the housing 101 (battery case 102) is arranged so that the electrode plate group 104, which will be described later, is arranged in a horizontal direction (direction perpendicular to the Z-axis direction), and the horizontal position is a position in which the housing 101 is arranged so that the electrode plate group 104 is arranged in a vertical direction (Z-axis direction) (see FIG. 1).

[0019] As shown in FIG. 1, the lead-acid battery 100 includes a housing 101 and a plate group 104. The housing 101 includes a battery case 102 and a lid 106. The battery case 102 is a substantially rectangular parallelepiped container with one end open, and is made of, for example, synthetic resin. Specifically, the battery case 102 has a rectangular cylindrical peripheral wall formed of four side walls 108 (108A to 108D) and a bottom 109 closing one end of the peripheral wall. In the horizontally placed state shown in FIG. 1, the first side wall 108A and the second side wall 108B face each other in the vertical direction (Z-axis direction), and the third side wall 108C and the fourth side wall 108D face each other in the horizontal direction (X-axis direction). An electrolyte (not shown) and the plate group 104 are accommodated in the internal space S of the housing 101. The electrolyte is, for example, dilute sulfuric acid.

[0020] (Configuration of electrode plate group 104) The electrode plate group 104 includes a plurality of flat positive electrode plates 110P, a plurality of flat negative electrode plates 110N, and a plurality of separators 120 arranged between the positive electrode plates 110P and the negative electrode plates 110N. Specifically, the plurality of positive electrode plates 110P and the plurality of negative electrode plates 110N are arranged alternately, one by one, with the separators 120 interposed between them. This results in a configuration in which a plurality of cells, each having one positive electrode plate 110P and one negative electrode plate 110N facing each other with the separators 120 interposed therebetween, are arranged in a predetermined direction (the Z-axis direction in the horizontally placed state in FIG. 1). Hereinafter, the arrangement direction of the cells is referred to as the "cell arrangement direction." The cell arrangement direction is an example of the arrangement direction of the electrode plate group in the claims.

[0021] Each of the plates 110P, 110N is a conductive member in which an active material is filled in a grid. One end side (negative side of the X-axis in FIG. 1) of the upper part of each positive plate 110P is provided with an ear 114P that protrudes upward. The positive plates 110P are connected to each other via the ears 114P by a current collector member (not shown) on the positive electrode side. The other end side (positive side of the X-axis in FIG. 1) of each negative plate 110N is provided with an ear (not shown) that protrudes upward. The negative plates 110N are connected to each other via the ears by a current collector member (not shown) on the negative electrode side.

[0022] Each positive electrode plate 110P has a pair of first legs 116P, 118P that protrude toward the bottom surface (bottom 109) of the battery case 102. Each negative electrode plate 110N has a pair of second legs 116N, 118N that protrude toward the bottom surface (bottom 109) of the battery case 102. The pair of first legs 116P, 118P and the pair of second legs 116N, 118N are arranged at different positions from each other when viewed from the cell arrangement direction. Specifically, the pair of first legs 116P, 118P and the pair of second legs 116N, 118N are arranged so as to be alternately arranged in the horizontal direction (X-axis direction). More specifically, the first foot 116P is located approximately directly below the ear 114P of the positive electrode plate 110P, and the second foot 116N is located approximately directly below the ear of the negative electrode plate 110N. The first foot 118P is disposed in a position closer to the second foot 116N, and the second foot 118N is disposed in a position closer to the first foot 116P.

[0023] (Configuration of the lid 106) Lid 106 is a substantially rectangular member, has a size corresponding to the opening of battery case 102, and is made of, for example, synthetic resin. Lid 106 is fitted into the opening of battery case 102, and lid 106 and battery case 102 are, for example, thermally welded together, thereby sealing internal space S of housing 101.

[0024] The lid 106 is provided with a positive electrode terminal portion 150P and a negative electrode terminal portion 150N. The positive electrode terminal portion 150P and the negative electrode terminal portion 150N are arranged on a diagonal line of the lid 106 (see FIG. 1). The positive electrode terminal portion 150P is electrically connected to the plurality of positive electrode plates 110P via a positive electrode side current collecting member. The negative electrode terminal portion 150N is electrically connected to the plurality of negative electrode plates 110N via the negative electrode side current collecting member.

[0025] A-2. Bottom configuration of battery container 102: Fig. 2 is an explanatory diagram showing the bottom configuration of the battery case 102 of the lead-acid battery 100 in this embodiment. Fig. 2 shows the configuration of the inner wall surface (bottom surface) of the bottom 109 when the lead-acid battery 100 is viewed from a direction perpendicular to the bottom surface of the battery case 102 (Y-axis direction in Fig. 2, hereinafter referred to as "bottom surface direction"). In Fig. 2, the lid 106 and the electrode plate group 104 are omitted, and first leg arrangement regions 116PL, 118PL and second leg arrangement regions 116NL, 118NL are shown. The meaning of each arrangement region is as follows: "First leg arrangement region 116PL": When the lead-acid battery 100 is viewed from the bottom surface, this is a region in which a row of a plurality of first legs 116P protruding from the electrode plate group 104 (a plurality of positive electrode plates 110P) is arranged. "First leg arrangement region 118PL": When the lead-acid battery 100 is viewed from the bottom surface, this is a region in which a row of a plurality of first legs 118P protruding from the electrode plate group 104 (a plurality of positive electrode plates 110P) is arranged. "Second leg arrangement region 116NL": When the lead-acid battery 100 is viewed from the bottom, this is a region in which a row of a plurality of second legs 116N protruding from the electrode plate group 104 (a plurality of negative electrode plates 110N) is arranged. "Second leg arrangement region 118NL": When the lead-acid battery 100 is viewed from the bottom, this is a region in which a row of a plurality of second legs 118N protruding from the electrode plate group 104 (a plurality of negative electrode plates 110N) is arranged.

[0026] As shown in FIG. 2, a plurality of support ribs 103P, 103N (two in this embodiment) for supporting each leg are formed on the bottom surface of the battery case 102. The positive electrode side support rib 103P is a convex portion (saddle) extending linearly along the cell arrangement direction (Z-axis direction) in the first leg arrangement region 116PL on the bottom surface of the battery case 102. A plurality of first legs 116P are arranged to face the positive electrode side support rib 103P. The positive electrode side support rib 103P extends over the entire length of the bottom surface of the battery case 102 in the cell arrangement direction. The negative electrode side support rib 103N is a convex portion (saddle) extending linearly along the cell arrangement direction in the second leg arrangement region 116NL on the bottom surface of the battery case 102. A plurality of second legs 116N are arranged to face the negative electrode side support rib 103N. The negative electrode support rib 103N extends over the entire length of the bottom surface of the battery case 102 in the cell arrangement direction. A space is formed between each of the electrode plates 110P, 110N and the bottom surface of the battery case 102 by these support ribs 103P, 103N.

[0027] As shown in Fig. 2, the bottom surface of the battery container 102 is provided with ribs (vertical ribs RL and horizontal ribs RW) that divide the intermediate region E1, which is sandwiched between the first leg arrangement regions 116PL, 118PL and the second leg arrangement regions 116NL, 118NL, into a plurality of regions when viewed from the bottom surface direction. The intermediate region E1 is an example of a specific region in the claims. A specific description will be given below.

[0028] A plurality of vertical ribs RL are formed on the bottom surface of the battery case 102, and each vertical rib RL divides each intermediate region E1 into a plurality of parts in the horizontal direction (X-axis direction in FIG. 2). Each vertical rib RL is a convex portion extending linearly along the cell arrangement direction in each intermediate region E1 on the bottom surface of the battery case 102. Each vertical rib RL extends over the entire length of the bottom surface of the battery case 102 in the cell arrangement direction. The vertical rib RL is an example of a second rib in the claims.

[0029] For example, when viewed from the bottom surface direction, a vertical rib RL is formed between the first leg arrangement region 116PL and the second leg arrangement region 118NL, and the first intermediate region E11 is divided into two regions arranged in a direction substantially perpendicular to the cell arrangement direction by the vertical rib RL. When viewed from the bottom surface direction, a vertical rib RL is formed between the second leg arrangement region 118NL and the first leg arrangement region 118PL, and the second intermediate region E12 is divided into two regions arranged in a direction substantially perpendicular to the cell arrangement direction by the vertical rib RL. When viewed from the bottom surface direction, a vertical rib RL is formed between the first leg arrangement region 118PL and the second leg arrangement region 116NL, and the third intermediate region E13 is divided into two regions arranged in a direction substantially perpendicular to the cell arrangement direction by the vertical rib RL.

[0030] A plurality of first horizontal ribs RW1 and a plurality of second horizontal ribs RW2 are formed on the bottom surface of the battery container 102. When viewed from the bottom surface direction, each first horizontal rib RW1 further divides one of the regions divided by the vertical rib RL in each intermediate region E1 into a plurality of regions in the cell arrangement direction (Z-axis direction). Each first horizontal rib RW1 is a convex portion extending linearly along the horizontal direction (X-axis direction). When viewed from the bottom surface direction, each second horizontal rib RW2 further divides the other of the regions divided by the vertical rib RL in each intermediate region E1 into a plurality of regions in the cell arrangement direction. Each second horizontal rib RW2 is a convex portion extending linearly along a direction perpendicular to the cell arrangement direction. The position of the joint between the first horizontal rib RW1 and the vertical rib RL and the position of the joint between the second horizontal rib RW2 and the vertical rib RL are different from each other in the cell arrangement direction. The first transverse rib RW1 is an example of a third rib in the claims, and the second transverse rib RW2 is an example of a fourth rib in the claims.

[0031] For example, one of the regions (regions on the negative side of the X-axis in FIG. 2) divided by the vertical rib RL is divided into three regions aligned in the cell arrangement direction by two first horizontal ribs RW1 aligned in the cell arrangement direction (Z-axis direction). The other of the regions (regions on the positive side of the X-axis in FIG. 2) divided by the vertical rib RL is divided into three regions aligned in the cell arrangement direction by two second horizontal ribs RW2 aligned in the cell arrangement direction. The positions of the two first horizontal ribs RW1 and the positions of the two second horizontal ribs RW2 are different from each other in the cell arrangement direction. Both ends of each first horizontal rib RW1 are connected to both the support rib 103P and the vertical rib RL adjacent to the support rib 103P. Each second horizontal rib RW2 is connected to both of a pair of vertical ribs RL adjacent to each other. The third intermediate region E13 is similar to the first intermediate region E11.

[0032] For example, one of the regions (the region on the positive side of the X-axis in FIG. 2) divided by the vertical rib RL is divided into three regions aligned in the cell arrangement direction by two first horizontal ribs RW1 aligned in the cell arrangement direction in the second intermediate region E12. The other region (the region on the negative side of the X-axis in FIG. 2) divided by the vertical rib RL is divided into three regions aligned in the cell arrangement direction by two second horizontal ribs RW2 aligned in the cell arrangement direction. The positions of the two first horizontal ribs RW1 and the positions of the two second horizontal ribs RW2 are different from each other in the cell arrangement direction. Note that both ends of each first horizontal rib RW1 are connected to both of a pair of vertical ribs RL adjacent to each other, and both ends of each second horizontal rib RW2 are connected to both of a pair of vertical ribs RL adjacent to each other.

[0033] The horizontal ribs RW (first horizontal rib RW1 and second horizontal rib RW2) are spaced apart from both of a pair of side walls (third side wall 108C and fourth side wall 108D) of the battery container 102 that are substantially parallel to the cell arrangement direction (Z-axis direction). Specifically, as shown in FIG. 2, no ribs are formed in a first end region E21 sandwiched between the first leg arrangement region 116PL and the third side wall 108C. No ribs are formed in a second end region E22 sandwiched between the second leg arrangement region 116NL and the fourth side wall 108D.

[0034] A-3. Advantages of this embodiment: Fig. 3 is an explanatory diagram showing the bottom configuration of a battery case 102x of a lead-acid battery 100x in a comparative example. Fig. 3 shows the configuration of the inner wall surface (bottom surface) of a bottom 109x when the lead-acid battery 100x is viewed from the bottom surface direction. In Fig. 3, as in Fig. 2, the cover 106 and the electrode plate group 104 are omitted, and the first leg arrangement regions 116PL, 118PL and the second leg arrangement regions 116NL, 118NL are shown.

[0035] As shown in FIG. 3, the lead-acid battery 100x in the comparative example is different from the lead-acid battery 100 in the present embodiment in that, although a support rib is formed on the bottom surface of the battery case 102x, neither vertical ribs nor horizontal ribs are formed. That is, in the comparative example, in addition to the above-mentioned positive electrode side support rib 103P and negative electrode side support rib 103N, a positive electrode side support rib 103Px and a negative electrode side support rib 103Nx are formed. The positive electrode side support rib 103Px is a convex portion extending linearly along the cell arrangement direction (Z-axis direction) in the first leg arrangement region 118PL on the bottom surface of the battery case 102. The negative electrode side support rib 103Nx is a convex portion extending linearly along the cell arrangement direction in the second leg arrangement region 118NL on the bottom surface of the battery case 102. No rib is formed in each intermediate region E1 to divide the intermediate region E1.

[0036] Here, in the lead-acid battery 100x of the comparative example, when it is placed vertically, the active material contained in the electrode plate group 104 is deposited on the bottom surface of the battery case 102x. When the lead-acid battery 100x is then placed horizontally, the active material deposited on the bottom surface of the battery case 102x is collected along the support rib 103P and the like at one location on one side (lower side, negative Z-axis direction in FIG. 3) in the cell arrangement direction, as shown by the arrow in FIG. 3. As a result, the first legs 116P, 118P of the positive electrode plate 110P and the second legs 116N, 118N of the negative electrode plate 110N are electrically connected and short-circuited through the active material collected at this one location. For example, the active material deposited in the first intermediate region E11 is all collected on the lower end side of the first intermediate region E11. As a result, the collected active material comes into contact with both the first leg 116P and the second leg 118N, causing a short circuit between the positive electrode plate 110P and the negative electrode plate 110N.

[0037] In contrast, in the lead-acid battery 100 of this embodiment, vertical ribs RL and horizontal ribs RW (hereinafter referred to as "vertical ribs RL, etc.") are formed on the bottom surface of the battery case 102. The vertical ribs RL, etc. are formed to divide each intermediate region E1 when viewed from the bottom surface direction. As a result, when the lead-acid battery 100 is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case 102 is dispersed into a plurality of regions divided by the vertical ribs RL, etc. As a result, according to this embodiment, compared to a comparative example not provided with the vertical ribs RL, etc., when the lead-acid battery 100 is changed from a vertically placed state to a horizontally placed state, it is possible to suppress a short circuit between the positive electrode plate 110P and the negative electrode plate 110N due to the active material accumulated on the bottom surface of the battery case 102 gathering in one place.

[0038] Specifically, in this embodiment, a plurality of vertical ribs RL are formed on the bottom surface of the battery case 102. Therefore, when the lead-acid battery 100 is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case 102 is dispersed into a plurality of regions divided in the horizontal direction (the X-axis direction in FIG. 2) by the vertical ribs RL. As a result, according to this embodiment, it is possible to prevent the active material accumulated on the bottom surface of the battery case 102 from gathering in one place and causing a short circuit between the positive electrode plate 110P and the negative electrode plate 110N.

[0039] In this embodiment, a horizontal rib RW is further formed on the bottom surface of the battery case 102. Therefore, when the lead-acid battery 100 is changed from a vertically placed state to a horizontally placed state, the active material accumulated on the bottom surface of the battery case 102 is dispersed into a plurality of regions divided to the left and right by the vertical rib RL, and further dispersed into a plurality of regions divided to the top and bottom (Z-axis direction in FIG. 2) by the horizontal ribs RW (first horizontal rib RW1, second horizontal rib RW2). Therefore, it is possible to more effectively prevent the active material accumulated on the bottom surface of the battery case 102 from gathering in one place and causing a short circuit between the positive electrode plate 110P and the negative electrode plate 110N.

[0040] Here, for example, in a configuration in which the position of the joint between the first horizontal rib RW1 and the vertical rib RL and the position of the joint between the second horizontal rib RW2 and the vertical rib RL are the same in the cell arrangement direction, the active material is collected in one place by the first horizontal rib RW1 and the second horizontal rib RW2, so that there is a risk of short-circuiting between the positive electrode plate 110P and the negative electrode plate 110N. In contrast, in this embodiment, the position of the joint between the first horizontal rib RW1 and the vertical rib RL and the position of the joint between the second horizontal rib RW2 and the vertical rib RL are different from each other in the cell arrangement direction. Therefore, compared to a configuration in which the position of the joint between the first horizontal rib RW1 and the vertical rib RL and the position of the joint between the second horizontal rib RW2 and the vertical rib RL are the same in the cell arrangement direction, it is possible to more effectively suppress the active material deposited on the bottom surface of the battery container 102 from collecting in one place and causing a short circuit between the positive electrode plate 110P and the negative electrode plate 110N.

[0041] In this embodiment, the transverse ribs RW (the first transverse rib RW1 and the second transverse rib RW2) are spaced apart from both of a pair of side walls (the third side wall 108C and the fourth side wall 108D) of the battery case 102 that are substantially parallel to the cell arrangement direction (Z-axis direction). Therefore, compared to a configuration in which the transverse rib RW is in contact with both of the pair of side walls, the rigidity difference between the peripheral wall and the bottom 109 of the battery case 102 is small, so that, for example, when the lead-acid battery 100 is deformed due to expansion, contraction, or the like, stress is concentrated at the boundary between the peripheral wall and the bottom 109 of the battery case 102, and damage to the battery case 102 can be suppressed. Note that, in the end region E2, even if the active material is gathered at one place, the positive electrode plate 110P and the negative electrode plate 110N are not short-circuited, so there is no need to form the transverse ribs RW.

[0042] In addition, in the configuration in which the vertical rib RL is formed on the bottom surface of the battery case 102 in addition to the support ribs 103P and 103N as in the present embodiment, the rigidity of the bottom 109 of the battery case 102 is increased, and the rigidity difference between the bottom 109 and the peripheral wall of the battery case 102 is increased. In this case, when the lead-acid battery 100 is deformed due to expansion or contraction, for example, stress is concentrated on the corners of the battery case 102, making the battery case 102 more likely to be damaged. In contrast, in the present embodiment, no support rib is formed on the bottom surface of the battery case 102 to support a part of the foot (first foot 118P, second foot 118N) protruding from the electrode plate group 104. This makes it possible to suppress damage to the battery case 102 due to the rigidity difference between the bottom 109 and the peripheral wall of the battery case 102, compared to a configuration in which all support ribs are formed to support the foot protruding from the electrode plate group 104.

[0043] B. Second embodiment: Fig. 4 is an explanatory diagram showing the bottom configuration of a battery case 102a of a lead-acid battery 100a in the second embodiment. Fig. 4 shows the configuration of the inner wall surface (bottom surface) of a bottom 109a when the lead-acid battery 100a is viewed from the bottom surface direction. In the following, among the configurations of the lead-acid battery 100a of the second embodiment, the same configurations as those of the lead-acid battery 100 of the first embodiment described above are denoted by the same reference numerals and the description thereof will be omitted as appropriate.

[0044] As shown in FIG. 4, in addition to the positive electrode side support rib 103P and the negative electrode side support rib 103N in the first embodiment, a positive electrode side support rib 103Pa and a negative electrode side support rib 103Na are formed on the bottom surface of the battery case 102a. The positive electrode side support rib 103Pa is a convex portion extending linearly along the cell arrangement direction (Z-axis direction) in the first foot arrangement region 118PL on the bottom surface of the battery case 102a. The negative electrode side support rib 103Na is a convex portion extending linearly along the cell arrangement direction in the second foot arrangement region 118NL on the bottom surface of the battery case 102a. Thus, in the second embodiment, support ribs 103P, 103Pa, 103N, and 103Na that support the multiple feet 116P, 118P, 116N, and 118N protruding from the electrode plate group 104 are arranged on all of the feet. Therefore, compared to a configuration in which support ribs are arranged only on some of the multiple legs protruding from the electrode plate group 104, it is possible to more reliably prevent damage to the battery case 102a by the legs when the lead-acid battery 100 is deformed due to expansion, contraction, etc.

[0045] As shown in FIG. 4, horizontal ribs RWa (first horizontal rib RWa1, second horizontal rib RWa2, and third horizontal rib RWa3) are formed on the bottom surface of the battery container 102a.

[0046] Each first transverse rib RWa1 divides each intermediate region E1 into a plurality of parts in the cell arrangement direction (Z-axis direction). Each first transverse rib RWa1 is a convex part extending linearly along the horizontal direction (X-axis direction). Each first transverse rib RWa1 is located at the center of each intermediate region E1 in the cell arrangement direction, and divides each intermediate region E1 into two equal parts. Each of the two ends of each first transverse rib RWa1 is in contact with two adjacent support ribs. Therefore, the active material deposited in one of the two regions divided by the first transverse rib RWa1 in each intermediate region E1 is prevented from moving to the other region. This makes it possible to more effectively prevent the active material deposited on the bottom surface of the battery container 102a from gathering in one place and causing a short circuit between the positive electrode plate 110P and the negative electrode plate 110N.

[0047] Each second horizontal rib RWa2 divides a part of each end region E2 into multiple parts in the cell arrangement direction (Z-axis direction). Each second horizontal rib RWa2 is a convex portion extending linearly along the horizontal direction (X-axis direction). One end of the second horizontal rib RWa2 contacts the rib (support ribs 103P, 103N) located at the end in the horizontal direction, and the other end of the second horizontal rib RWa2 is spaced apart from the side wall 108 (108C, 108D) of the battery container 102a.

[0048] Each third transverse rib RWa3 divides a part of each end region E2 into multiple parts in the cell arrangement direction. Each third transverse rib RWa3 is a convex portion extending linearly along the horizontal direction. One end of the third transverse rib RWa3 contacts the side wall 108 of the battery case 102a, and the other end of the second transverse rib RWa2 is spaced apart from the ribs (support ribs 103P, 103N) located at the ends in the horizontal direction.

[0049] The second transverse rib RWa2 and the third transverse rib RWa3 are arranged at different positions in the cell arrangement direction. When viewed from the cell arrangement direction, a part of the second transverse rib RWa2 and a part of the third transverse rib RWa3 overlap each other. This makes it possible to suppress stress concentration at the boundary between the side wall 108 and the bottom 109a of the battery case 102a and damage to the battery case 102a when the lead-acid battery 100a is deformed due to expansion or contraction, as compared with a configuration in which the transverse rib is in contact with both the side wall 108 of the battery case 102a and the rib located at the horizontal end. It also makes it possible to suppress the active material accumulated on the bottom surface of the battery case 102a from gathering in one place and causing a short circuit between the first leg of the positive electrode plate and the second leg of the negative electrode plate.

[0050] As shown in FIG. 4, vertical ribs RLa (first vertical rib RLa1, second vertical rib RLa2) are formed on the bottom surface of the battery case 102a. Here, the vertical ribs RL in the first embodiment are configured to divide each intermediate region E1 into a plurality of parts. That is, one end of each vertical rib RL is in contact with the first side wall 108A of the battery case 102, and the other end of each vertical rib RL is in contact with the second side wall 108B (see FIG. 2). In contrast, the vertical ribs RLa in the second embodiment are configured to divide a portion of each intermediate region E1 into a plurality of parts.

[0051] Each first vertical rib RLa1 divides a part of each intermediate region E1 divided by the first horizontal rib RWa1 into multiple parts in the horizontal direction (X-axis direction). Each first vertical rib RLa1 is a convex portion extending linearly along the cell arrangement direction (Z-axis direction). One end of the first vertical rib RLa1 contacts the side wall 108 (108A, 108B) of the battery case 102a, and the other end of the second horizontal rib RWa2 is spaced apart from the first horizontal rib RWa1.

[0052] Each second longitudinal rib RLa2 divides a part of each intermediate region E1 divided by the first transverse rib RWa1 into multiple parts in the horizontal direction (X-axis direction). Each second longitudinal rib RLa2 is a convex portion extending linearly along the cell arrangement direction (Z-axis direction). One end of the second longitudinal rib RLa2 contacts the first transverse rib RWa1, and the other end of the second transverse rib RWa2 is spaced apart from the side wall 108 (108A, 108B) of the battery container 102a.

[0053] The first vertical rib RLa1 and the second vertical rib RLa2 are spaced apart from each other in the cell arrangement direction (Z-axis direction). With this configuration, for example, when the lead-acid battery 100a is arranged horizontally with the second side wall 108B facing downward (see FIG. 4), the active material deposited in each intermediate region E1 is dispersed into two in the cell arrangement direction by the first horizontal rib RWa1. Furthermore, the active material deposited in the region above the first horizontal rib RWa1 is dispersed into two by the second vertical rib RLa2, and the active material deposited in the region below the first horizontal rib RWa1 is dispersed into two by the first vertical rib RLa1. In this way, according to the second embodiment, the active material deposited in each intermediate region E1 can be dispersed into four locations. In addition, in the lead-acid battery 100a, the rib configuration at the bottom 109a is symmetrical in the cell arrangement direction, so that even when the battery is placed horizontally with the first side wall 108A facing down, the active material deposited in each intermediate region E1 can be dispersed to four locations.

[0054] As described above, in the second embodiment, support ribs are provided for all of the legs protruding from the plate pack 104, and the rigidity of the bottom 109a of the battery case 102a is accordingly increased. On the other hand, one end of the vertical rib RLa is spaced from the side wall 108 of the battery case 102a, and the increase in the rigidity of the bottom 109a due to the vertical rib RLa is suppressed. This makes it possible to suppress damage to the battery case 102a due to the legs, while suppressing a short circuit between the positive and negative plates due to the active material accumulated on the bottom surface of the battery case 102a.

[0055] C. Third embodiment: Fig. 5 is an explanatory diagram showing the bottom configuration of a battery case 102b of a lead-acid battery 100b in the third embodiment. Fig. 5 shows the configuration of the inner wall surface (bottom surface) of a bottom 109b when the lead-acid battery 100b is viewed from the bottom surface direction. In the following, among the configurations of the lead-acid battery 100b of the third embodiment, the same configurations as those of the lead-acid battery 100 of the first embodiment described above are denoted by the same reference numerals and the description thereof will be omitted as appropriate.

[0056] 5, in addition to the positive electrode side support rib 103P and the negative electrode side support rib 103N in the first embodiment, a positive electrode side support rib 103Pa and a negative electrode side support rib 103Na are formed on the bottom surface of the battery container 102b. The support ribs 103Pa and 103Na are similar to those in the second embodiment, and therefore will not be described.

[0057] As shown in FIG. 5, a horizontal rib RWb is formed on the bottom surface of the battery case 102b. Each horizontal rib RWb divides each intermediate region E1 and each end region E2 into a plurality of parts in the cell arrangement direction (Z-axis direction). Specifically, four horizontal ribs RWb are arranged at equal intervals in the cell arrangement direction, and each region E1, E2 is divided into five parts. The horizontal rib RWb is a convex part that extends linearly along the horizontal direction (X-axis direction). The horizontal rib RWb contacts a pair of side walls 108C, 108D of the battery case 102b. In the third embodiment, no vertical rib is formed.

[0058] D. Variations: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0059] The configuration of the lead-acid battery 100 in the above embodiment is merely an example, and various modifications are possible. For example, the housing 101 may have an internal space S divided into a plurality of cell chambers, and each cell chamber may contain an electrolyte and an electrode plate group 104. In the above embodiment, the positive electrode and the negative electrode are exemplified as conductive members in which an active material is filled in a grid, but the positive electrode may be, for example, an array of a plurality of braided tubes.

[0060] In the above embodiment, each of the electrode plates 110P, 110N has a pair of legs, but may have one leg or three or more legs. Also, the number of legs of the positive electrode plate 110P and the number of legs of the negative electrode plate 110N may be different from each other.

[0061] In the above embodiment, two support ribs 103P, 103N are formed on the bottom surface of the battery case 102, but the bottom surface of the battery case 102 may be configured to have no support ribs for supporting the feet of the electrode plates, or may have three or more support ribs. In addition, at least one end of the support ribs 103P, 103N may be spaced apart from the peripheral wall of the battery case 102.

[0062] In the above embodiment, the shape of the vertical rib RL is a shape extending linearly along the cell arrangement direction, but it may be, for example, a shape extending in a direction inclined at an angle to the cell arrangement direction, or a non-linear shape including curved or bent parts. Also, for example, a configuration in which multiple vertical ribs RL are formed in one intermediate region E1 may be used.

[0063] In the above embodiment, the shape of the horizontal rib RW is a shape extending linearly along a direction perpendicular to the cell arrangement direction, but it may be a shape extending in a direction inclined obliquely to the perpendicular direction, or may be a non-linear shape including a curved portion or a bent portion. Also, in the above embodiment, a configuration may be used in which one horizontal rib RW is formed in one region divided by a vertical rib RL, or a configuration may be used in which three or more horizontal ribs RW are formed.

[0064] In the above embodiment, the horizontal ribs RW (RW1, RW2) may not be formed on the bottom surface of the battery case 102. Even in the case where only the vertical ribs RL are provided, the active material deposited on the bottom surface of the battery case 102 is dispersed into a plurality of regions separated by the vertical ribs RL, so that the positive electrode plate 110P and the negative electrode plate 110N can be prevented from being short-circuited due to the active material deposited on the bottom surface of the battery case 102. In the above embodiment, the bottom surface of the battery case 102 may be provided with only horizontal ribs that divide each intermediate region E1 into a plurality of regions in the cell arrangement direction. Even in the case where only the horizontal ribs are provided, the active material deposited on the bottom surface of the battery case 102 is dispersed into a plurality of regions separated by the horizontal ribs, so that the positive electrode plate 110P and the negative electrode plate 110N can be prevented from being short-circuited due to the active material deposited on the bottom surface of the battery case 102. The horizontal ribs are an example of the first rib in the claims.

[0065] In the above embodiment, the horizontal rib RW may be configured to be in contact with at least one of the pair of side walls (third side wall 108C, fourth side wall 108D). In addition, in the above embodiment, a horizontal rib or a vertical rib may be formed in the end region E2. However, it is preferable that at least one end of the horizontal rib or the vertical rib is separated from the peripheral wall of the battery case 102. With such a configuration, it is possible to suppress the stress concentration at the corners of the battery case 102, which is caused by the existence of the rib increasing the rigidity difference between the bottom of the battery case 102 and the peripheral wall, and thus the battery case 102 becoming more susceptible to damage. In addition, at least one of the above ribs (RW, RL, 103P, 103N) may be separate from the battery case 102.

[0066] The materials used to form the components of the lead-acid battery 100 in the above embodiment are merely examples and can be modified in various ways. [Explanation of symbols]

[0067] 100, 100a, 100b, 100x: Lead-acid battery 101: Housing 102, 102a, 102b, 102x: Battery case 103N, 103Na, 103Nx, 103P, 103Pa, 103Px: Support rib 104: Plate group 106: Lid 108A: First side wall 108B: Second side wall 108C: Third side wall 108D: Fourth side wall 109, 109a, 109b, 109x: Bottom 110N: Negative electrode plate 110P: Positive electrode plate 114P: Ear portion 116N, 118N: Second foot portion 116NL, 118NL: Second foot arrangement area 116P, 118P: First foot portion 116PL, 118PL: First leg arrangement region 120: Separator 150N: Terminal portion 150P: Terminal portion E11: First intermediate region E12: Second intermediate region E13: Third intermediate region E21: First end region E22: Second end region RL (RLa1, RLa2): Vertical rib RW (RW1, RW2, RWa1, RWa2, RWa3, RWb) S: Internal space

Claims

1. A lead-acid battery, A housing having a battery case with one end open and a lid that seals the opening of the battery case; and an electrode plate group having a plurality of positive electrode plates and a plurality of negative electrode plates alternately arranged with separators interposed between them in the battery case, Each of the positive electrode plates has a first foot portion protruding toward the bottom surface of the battery case, and each of the negative electrode plates has a second foot portion protruding toward the bottom surface of the battery case; the first leg portion and the second leg portion are disposed at different positions from each other when viewed from the arrangement direction of the electrode plate group, A rib is formed on the bottom surface of the battery case, the rib extending from an end of a specific region sandwiched between a row of the first legs protruding from the electrode plate group and a row of the second legs when viewed from a direction perpendicular to the bottom surface, and dividing at least a part of the specific region into multiple parts; The rib includes a first rib that divides the specific region into a plurality of regions in an arrangement direction of the electrode plate group, The first rib is spaced from at least one of a pair of side walls of the battery case that are substantially parallel to the arrangement direction of the electrode plate group. Lead acid battery.

2. A lead-acid battery, A housing having a battery case with one end open and a lid that seals the opening of the battery case; and an electrode plate group having a plurality of positive electrode plates and a plurality of negative electrode plates alternately arranged with separators interposed between them in the battery case, Each of the positive electrode plates has a first foot portion protruding toward the bottom surface of the battery case, and each of the negative electrode plates has a second foot portion protruding toward the bottom surface of the battery case; the first leg portion and the second leg portion are disposed at different positions from each other when viewed from the arrangement direction of the electrode plate group, A rib is formed on the bottom surface of the battery case, the rib extending from an end of a specific region sandwiched between a row of the first legs protruding from the electrode plate group and a row of the second legs when viewed from a direction perpendicular to the bottom surface, and dividing at least a part of the specific region into multiple parts; the rib includes a second rib that divides the specific region into a plurality of regions in a direction substantially perpendicular to an arrangement direction of the electrode plate group, the rib includes a third rib that further divides one of the specific regions divided by the second rib into a plurality of regions in the arrangement direction of the electrode plate pack, and a fourth rib that further divides the other region divided by the second rib into a plurality of regions in the arrangement direction of the electrode plate pack, a position of a joint portion between the second rib and the third rib and a position of a joint portion between the second rib and the fourth rib are different from each other in an arrangement direction of the electrode plate group. Lead acid battery.

3. A lead-acid battery as claimed in claim 2, The second rib extends from one of a pair of side walls of the container that are substantially perpendicular to an arrangement direction of the electrode plate pack, and is spaced apart from the other side wall. Lead acid battery.

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