Control valve type lead-acid storage battery

Abstract

To provide a control valve type lead-acid storage battery of which productivity is improved.SOLUTION: A control valve type lead-acid storage battery comprises: a battery tank; at least one electrode group housed into at least one cell chamber provided to the battery tank; and a strap connecting a group of lugs of positive electrodes and negative electrodes of the electrode group. A vertical direction in the case where the control valve type lead-acid storage battery is stood is called an upper side and a lower side, and the strap and a flat terminal are bonded so that the flat type terminal is extended to the lower side of the strap. The flat type terminal contains: a terminal conductive part extended to a bonding portion that is electrically connected to an external part; and a terminal inclination part bonded to the group of lugs. A curvature angle between an extension direction of the terminal conductive part and one part or a whole part of the terminal inclination part is 15 degrees or more and 50 degrees or less.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a valve regulated lead-acid battery. [Background technology]

[0002] Conventionally, flat terminals are used for the positive and negative terminals of a controlled lead-acid battery, which are used for connection to the outside during charging and discharging. The flat terminals are electrically connected to the positive and negative electrode groups by welding or soldering with a strap. When using the cast-on-strap method, welding or soldering is generally performed while the controlled lead-acid battery is in an inverted state. For the convenience of welding the flat terminals when inverted, various innovations have been made in the shape of the flat terminals, such as bending the flat terminals.

[0003] In Patent Document 1, the applicant describes flat terminals as Faston terminals, and discloses a manufacturing method for lead-acid batteries in which the upper end of the Faston terminal is brought close to the lug of the electrode plate group and welded to the upper end, and the welding work is performed while the Faston terminal is separated by at least 0.8 mm from the wall of the battery case in the vicinity of the Faston terminal. The manufacturing method disclosed in Patent Document 1 makes it possible to prevent defects caused by peeling of the primer due to heat, thereby improving the productivity of lead-acid batteries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-223884 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, even with the above-mentioned improvement in productivity, there remains a problem that, when welding flat terminals in an inverted state, there is a certain probability that the tip of the flat terminal will not be embedded shallowly into the strap. If the tip of the flat terminal is not embedded deep enough into the strap, there is a possibility that the battery performance will not be fully utilized due to an increase in internal resistance, etc. If it is not embedded deep enough, the joint will be reinforced by soldering, etc., but this reduces productivity.

[0006] Therefore, the present invention provides a controlled lead-acid battery that improves productivity while ensuring sufficient bonding strength. [Means for solving the problem]

[0007] The present inventors have carried out various investigations to further improve the invention described in the above Patent Document 1. As a result, from a first viewpoint, the inventors discovered that in a valve-regulated lead-acid battery comprising a battery case, at least one electrode group contained in at least one cell chamber provided in the battery case, and a strap joining a lug group of a positive electrode or a negative electrode of the electrode group, if the following is provided, the lead or lead alloy will surround the flat terminals well during welding, reducing shallow embedment in the strap and improving productivity. (1) Further comprising a flat terminal joined to the strap. (2) The up and down directions when the valve-regulated lead-acid battery is held upright are referred to as the upper and lower directions, respectively, and the strap and the flat terminal are joined so that the flat terminal extends below the strap. (3) The flat terminal includes a terminal lead-out portion that extends to a joining portion for electrical connection with the outside, and a terminal inclined portion that is joined to the lug group. (4) A bending angle between the extension direction of the terminal lead-out portion and a part or the entirety of the terminal inclined portion is 15 degrees or more and 50 degrees or less.

[0008] Furthermore, in a second aspect, in addition to the above-mentioned first aspect, the valve regulated lead-acid battery may be characterized in that the bending angle is equal to or greater than 15 degrees and equal to or less than 40 degrees.

[0009] Furthermore, in a third aspect, in addition to the first or second aspect, the valve-regulated lead-acid battery may be characterized in that 30% or more of the entire inclined terminal portion is embedded inside the strap, and both sides of the embedded inclined terminal portion are bonded to the lead or lead alloy that forms the strap. Effect of the Invention

[0010] The present invention provides a controlled lead-acid battery that improves productivity while ensuring sufficient bonding strength. [Brief description of the drawings]

[0011] [Figure 1] 1 is an external view of a valve-regulated lead-acid battery according to a first embodiment of the present invention; [Diagram 2] FIG. 2 is a YZ plan view of the valve-regulated lead-acid battery shown in FIG. [Diagram 3] 3 is a cross-sectional view taken along line III-III of the valve-regulated lead-acid battery shown in FIG. 2. [Figure 4] FIG. 2 is a side view showing the flat terminal of the first embodiment. [Diagram 5] FIG. 13 is a side view showing a flat terminal of a sixth embodiment. [Figure 6] FIG. 13 is a side view showing the flat terminal of the seventh embodiment. [Figure 7] FIG. 13 is a side view showing the flat terminal of the eighth embodiment. [Figure 8] FIG. 13 is a side view showing the flat terminal of the ninth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an external view of a valve-regulated lead-acid battery according to a first embodiment of the present invention, FIG. 2 is a YZ plan view of the valve-regulated lead-acid battery shown in FIG. 1, and FIG. 3 is a III-III sectional view of the valve-regulated lead-acid battery shown in FIG. 2.

[0013] Hereinafter, a controlled lead-acid battery according to an embodiment of the present invention will be described, but the present invention is not limited to the following. In the embodiment described below, technically preferable limitations are imposed for carrying out the present invention, but these limitations are not essential requirements of the present invention. Furthermore, the definitions of directions such as up and down in the present invention are merely for the convenience of explanation and do not limit the technical ideas of the present disclosure.

[0014] <Shape of valve-regulated lead-acid battery> Fig. 1 is an external view of a valve-regulated lead-acid battery according to a first embodiment of the present invention, Fig. 2 is a YZ plan view of the valve-regulated lead-acid battery shown in Fig. 1, and Fig. 3 is a III-III sectional view of the valve-regulated lead-acid battery shown in Fig. 2. For convenience, in the specification, up and down are defined along the Z-axis direction, Fig. 1 is regarded as an upright state, and the direction with the ears is regarded as up.

[0015] 1 to 3, the valve-regulated lead-acid battery according to this embodiment includes a monoblock battery case 1 (sometimes simply referred to as a battery case in this specification), two cell chambers 3 defined by partition walls 2 inside the monoblock battery case 1, two electrode groups 4 housed in each of the two cell chambers 3, a positive electrode strap PS connecting the positive electrode lugs 4a of each of the two electrode groups 4 by welding, a negative electrode strap NS connecting the negative electrode lugs 4b by welding, a flat positive terminal 6 connected to the positive electrode lug group 4a on the underside of the positive electrode strap PS by welding, and a flat negative terminal 6 connected to the negative electrode lug group 4b on the underside of the negative electrode strap NS by welding.

[0016] The monoblock battery case 1 has an end wall 1a, an adherend wall portion 1b, and L-shaped holding frames 8a and 8b. The end wall 1a is provided with two terminal holders 5 that respectively hold a flat terminal 6 for a positive electrode corresponding to the positive electrode strap PS of one (left) of the two plate groups 4, and a flat terminal 6 for a negative electrode corresponding to the negative electrode strap NS of the other (right) of the plate groups 4, in an insertable manner.

[0017] The two terminal holders 5 are formed of two holding groove frames 5a and two recessed grooves 5b provided corresponding to the two electrode plate groups 4, respectively. In each of the two holding groove frames 5a, the flat terminal 6 is inserted through the engaging protrusion 7 and engaged and held by the terminal lead-out portion 6b. The end of the terminal lead-out portion 6b opposite to the terminal inclined portion is provided so as to protrude downward and outward from the recessed groove 5b, the front of which is open. The flat terminal 6 has a flat plate-like structure made of, for example, a metal or an alloy, and is composed of a terminal inclined portion 6a and a terminal lead-out portion 6b.

[0018] The adherend wall 1b is adhered to an adhesive filled in a recess on the back surface of a battery case lid (not shown). At this time, the adherend wall 1b may be subjected to a primer treatment and may be previously coated with a primer coating film P. The L-shaped retaining frames 8a, 8b are provided on the left and right sides of the end wall 1a of the battery case 1 by integral molding so as to protrude.

[0019] Regarding welding of the positive electrode strap PS and the negative electrode strap NS, when strap welding of the positive electrode lug group 4a and the negative electrode lug group 4b is performed according to the well-known cast-on-strap method, the terminal inclined portion 6a of the flat terminal 6 is welded adjacent to the side of the positive electrode lug group 4a and the negative electrode lug group 4b, in other words, to the right end in the short direction of the positive electrode strap PS and the negative electrode strap NS (see Figure 3). For this reason, the positive electrode lug group 4a is welded by the positive electrode strap PS, and at the same time, the terminal inclined portion 6a of the positive flat terminal 6 is welded to be integrated with the cast strap. Also, the negative electrode lug group 4b is welded by the negative electrode strap NS, and at the same time, the terminal inclined portion 6a of the negative fasten terminal 6 is welded to be integrated with the strap.

[0020] <Flat terminal shape> FIG. 4 is a side view of a flat terminal 6 of the present invention in one embodiment. The flat terminal 6 has the following features. (1) The flat terminal 6 includes a terminal lead-out portion 6b that extends to a connection portion for electrical connection with the outside, and a terminal inclined portion 6a that is joined to the lugs. (2) The bending angle between the extending direction of the terminal lead-out portion 6b and a part or the whole of the terminal inclined portion 6a is 15 degrees or more and 50 degrees or less. For convenience, the portion where the terminal lead-out portion 6b and the terminal inclined portion 6a are connected is called a forming point 6c. The above features are useful because the bend surface improves lead flow and reduces the chance of welding at the ends of the strap, improving manufacturability. Also, it is preferable that a part or the whole of the terminal inclined portion 6a is inclined from a part or the whole of the terminal lead-out portion 6b toward the center of the valve regulated lead-acid battery of the present invention.

[0021] 4, the terminal lead-out portion 6b is a portion that defines the longitudinal direction of the entire flat terminal 6, and in this embodiment, is disposed so that a portion of it substantially coincides with the vertical direction. Also, in this embodiment, the short side direction (see FIG. 3) of the lower surface of the strap NS is disposed so as to substantially coincide with the horizontal direction.

[0022] The terminal lead-out portion 6b is connected integrally with the terminal inclined portion 6a at the forming point 6c, and this terminal inclined portion 6a is formed by pressing or the like so as to have a predetermined angle with the vertical direction at the forming point 6c. In addition, the terminal inclined portion 6a is often embedded inside the strap NS from the lower surface of the strap NS so as to have a predetermined angle with the horizontal direction.

[0023] Furthermore, from a second viewpoint, in addition to the above-mentioned first viewpoint, the valve regulated lead-acid battery may be characterized in that a bending angle of a part of the terminal inclined portion 6a and a part of the terminal lead-out portion 6b is 15 degrees or more and 40 degrees or less. The reason why it is useful to have the above-mentioned characteristics is that when lead or lead alloy is poured to make the strap, if the surface has the above-mentioned angle, the probability of obtaining a valve-regulated lead-acid battery with even stronger adhesion increases, and productivity is further improved.

[0024] Furthermore, in a third aspect, in addition to the first or second aspect, the valve-regulated lead-acid battery may be characterized in that 30% or more of the entire terminal inclined portion 6a is embedded inside the strap, and both sides of the embedded terminal inclined portion 6a are joined to the lead or lead alloy that forms the strap. The reason why it is useful to have the above characteristics is that if it is 30% or more, the internal resistance will decrease, resulting in a battery with good performance. However, if it is more than 120%, that is, if the entire terminal inclined portion 6a and part of the terminal lead-out portion 6b are embedded inside the strap, there is a high possibility that excess lead or lead alloy is used. Therefore, it is preferable that it is 120% or less.

[0025] The area of ​​the part or the whole of the terminal inclined portion 6a, which has a bending angle of 15 degrees or more and 50 degrees or less with respect to the part or the whole of the terminal lead-out portion 6b, is preferably 20% or more of the terminal inclined portion 6a, more preferably 50% or more, and further preferably 80% or more. This is because a certain percentage of the area improves the flow of lead and reduces the probability of welding at the end of the strap, which strongly improves productivity. It is desirable that a part or all of the terminal lead-out portion 6b, which has a bending angle of 15 degrees or more and 50 degrees or less with respect to a part or all of the terminal inclined portion 6a, is adjacent to the forming point 6c.

[0026] The portion of the terminal inclined portion 6a where the bending angle with respect to a part or the whole of the terminal lead-out portion 6b is not 15 degrees or more and 50 degrees or less may have a bend or the like that does not contact the wall surface or the lid of the valve-regulated lead-acid battery. For example, it is preferable that the surface connects the portion of the terminal inclined portion 6a where the bending angle is 15 degrees or more and 50 degrees or less and the forming point 6c on both the upper and lower sides of the surface having the line segment connecting the above-mentioned portion and the forming point 6c in the shortest distance within a radius of curvature of the same as the length of the line segment to infinity, but it may also have a shape like a step of a staircase. As another example, the terminal inclined portion 6a may have a hook-shaped bend at the end of the flat terminal. The hook may be a curved surface. There may be multiple hooks.

[0027] The terminal lead-out portion 6b preferably has one or more bends. When a flat terminal is welded to the valve-regulated lead-acid battery and the valve-regulated lead-acid battery is stood upright, a forming point 6c is present at one end above the terminal lead-out portion.

[0028] The terminal lead-out portion 6b has a flat plate-like portion. The flat plate-like portion means a state in which the terminal lead-out portion 6b is made of a flat plate. However, the terminal lead-out portion 6b may have minute irregularities or notches, and the thickness or width of the flat plate may vary depending on the position. The terminal inclined portion 6a may be, for example, a flat plate-like portion or a curved plate-like portion. In some cases, the terminal inclined portion 6a and the terminal lead-out 6b in the vicinity of the forming point 6c form an arc. The terminal inclined portion 6a may have a bend, but if a bend exists in a portion that is not welded to the lead or lead alloy and is located closer to the strap than the center of the flat portion of the terminal lead-out portion 6b, the bend closest to the lead or lead alloy is deemed to be the forming point 6c. If the entire terminal inclined portion 6a and part of the flat portion of the terminal lead-out portion 6b are embedded in lead or lead alloy, the bend welded to the lead or lead alloy and closest to the end of the terminal lead-out portion 6b that is not embedded in lead alloy is deemed to be the forming point 6c. The portion embedded in lead or lead alloy refers to the portion of the flat terminal where both sides are fused with lead or lead alloy.

[0029] In this embodiment, the proportion of the terminal inclined portion 6a embedded in the strap is 30% or more of the entire terminal inclined portion 6a. Both sides of this 30% portion are joined to the lead or lead alloy that is the material forming the strap NS. In this embodiment, the distance from the embedding point B to the right end of the short side of the lower surface of the strap is 5 mm.

[0030] The most preferred form of the flat terminal 6 is as shown in Fig. 4. Specifically, it has a flat plate-like portion without any unevenness, the forming point 6c is a bend at one place, and has a lead-out portion with multiple bends, etc. This form is preferred because it is economical as it can be simply processed while still achieving the effects of the present invention, and in addition, the lead-out portion supports the terminal while contacting the wall of the valve-regulated lead-acid battery, preventing significant tilting of the terminal and thus preventing damage, and also facilitating connection to the outside.

[0031] In this specification, unless otherwise specified, the angle between the faces refers to the angle that becomes an acute angle or a right angle when both faces are extended. Therefore, unless otherwise specified, the maximum angle between the faces is 90 degrees. However, the bending angle of a part or all of the terminal lead-out portion 6b and a part or all of the terminal inclined portion 6a refers to the degree to which a part or all of the terminal inclined portion 6a is inclined downward from the upper part of the part or all of the terminal lead-out portion 6b when the part or all of the terminal lead-out portion 6b is extended upward when the valve-regulated lead-acid battery is upright. Therefore, the maximum bending angle of a part or all of the terminal lead-out portion 6b and a part or all of the terminal inclined portion 6a is 180 degrees. Furthermore, in this specification, unless otherwise specified, the length refers to the distance along the curved surface, whether it is two points on the curved surface, a straight line on the curved surface and one point on the curved surface, or a surface intersecting the curved surface and one point on the curved surface, and does not mean the shortest distance ignoring the curved surface. Unless otherwise specified, the length is measured along one surface of the flat terminal 6.

[0032] <Production of battery containers> In manufacturing a lead-acid battery having flat terminals 6 of the present invention, a battery case is prepared as follows. A monoblock battery case 1 is produced as a molded synthetic resin battery case, for example made of PP, with the interior of the battery case consisting of six cell chambers, with three cell chambers arranged in two rows in the longitudinal direction separated by a cross-shaped partition wall, and with a terminal holder integrally formed on the outer surface of one end wall in the longitudinal direction for inserting and holding the lower end of a rectangular flat terminal 6. On the other hand, a battery case cover to be applied to the battery case is molded, for example, from ABS as a material, and a box-shaped battery case cover is prepared, which has recesses on the back surface to accommodate the bonded wall parts at the upper ends of the peripheral side walls and the intermediate partition wall of the battery case, the straps connecting the positive electrode lugs 4a and the negative electrode lugs 4b of the electrode plate group between adjacent cell chambers that are perpendicular to the upper part of the partition wall, and the bonded wall parts at the upper ends of one or the other end walls of the monoblock battery case 1, the positive electrode lugs 4a and the negative electrode lugs 4b of the electrode plate group in the cell chamber located at the end of the monoblock battery case 1, and the upper ends of the positive and negative flat terminals 6 arranged along the end wall of the monoblock battery case 1, and the recesses to accommodate the adhesive for bonding and fixing them. This configuration is a battery case and a battery case cover of a well-known structure.

[0033] <Terminal manufacturing> A flat terminal 6 for use in the present invention is prepared. The flat terminal 6 is made of a conductive metal or alloy, and is generally made by bending a single metal or alloy plate multiple times, but may also be a cast product. Examples of conductive metals or alloys include lead, lead alloys, copper, and brass. Of these, brass is preferred. The thickness of the flat terminal 6 is preferably 0.4 mm to 1.0 mm. The width of the flat terminal 6 is preferably 2.5 mm to 5 mm. The length of the flat terminal 6 is not the distance on the curved surface, but the total length from one end to the other end, and is preferably 15 mm to 35 mm. As described below, the flat terminals 6 are intended to be welded to the electrode group at the lid of the battery case 1 by lead or a lead alloy and electrically connected to the electrode group. At that time, two types of flat terminals 6 are required for one valve-regulated lead-acid battery: one flat terminal 6 used as a positive electrode terminal and one flat terminal 6 used as a negative electrode terminal, so at least two flat terminals 6 are arranged for one valve-regulated lead-acid battery. Depending on the battery size, there may be three or more terminals for one valve-regulated lead-acid battery, but an even number is preferable. In the present invention, it is preferable that all of the flat terminals have the shape described above, but it is not essential that all of them have the shape described above.

[0034] <Manufacture of valve-regulated lead-acid batteries> A positive electrode plate made of a grid substrate made of lead or a lead alloy filled with a paste-like active material, and a negative electrode plate made of a grid substrate made of lead or a lead alloy filled with a paste-like active material containing carbon are laminated via a retainer mat mainly made of glass fiber to form an electrode plate group, the electrode plate group is then placed in a battery case 1 under high pressure and the lid is sealed, and then the battery case 1 is charged by injecting a dilute sulfuric acid electrolyte as described above, and finally a valve-regulated lead-acid battery is manufactured by covering the openings for injecting and venting the electrolyte provided in the lid with a control valve. The control valve is normally closed to keep the battery airtight, and opens to release pressure when the internal pressure of the battery rises during charging, etc.

[0035] Here, the electrode plate group is stored in the battery case 1 while being held in a high pressure state, i.e., at 40 to 100 kPa, preferably 40 to 70 kPa. If the pressure is less than the lower limit, the effect of suppressing softening of the positive electrode active material is weakened, whereas if the pressure is more than the upper limit, it becomes difficult to insert the electrode plate group into the battery case 1, and the distance between the positive and negative electrode plates becomes shorter, making it easier for a short circuit to occur. Regarding the compression (pressure) of the electrode plate group, both sides of the outermost electrode plate of the electrode plate group are sandwiched between smooth plates in parallel, and pressure is applied from the outside using a press machine perpendicular to the plates sandwiching the electrode plate group, so that the thickness of the electrode plate group is compressed to the same width as the inner dimension of the battery case 1 into which it will be inserted, and in this state only the electrode plate group is inserted into the battery case 1.

[0036] In the present invention, the positive plate formed by filling a grid substrate made of lead or a lead alloy with a paste-like active material, the negative plate formed by filling a grid substrate made of lead or a lead alloy with a paste-like active material containing carbon, and the retainer mat mainly made of glass fiber can be any known product manufactured by a known method. Here, the amount of carbon contained in the paste-like active material filled in the negative plate is preferably 0.01 to 5.0 mass% relative to the amount of the negative active material. If the amount exceeds the upper limit, the outflow of carbon during the formation of the battery container 1 may not be sufficiently suppressed, and the strength of the negative active material may decrease, causing the active material to fall off from the negative electrode and causing a short circuit. On the other hand, if the amount is less than the lower limit, the charge acceptance of the negative electrode may not be sufficiently improved. In addition, these positive and negative plates are alternately stacked via a retainer mat according to a conventional method to form an electrode plate group, and are assembled into the battery container 1 at the above group pressure.

[0037] Then, using the cast-on-strap method, the flat terminals 6, the battery case 1, the lid, and the lugs of the plate group are welded to each other at both the positive and negative poles to form a strap with the controlled lead-acid battery inverted. The amount of lead or lead alloy used during welding should be 2 to 5 mm from the bottom when the battery is inverted. The material of the strap is lead or a lead alloy, and the most preferred material is a lead alloy. A dilute sulfuric acid electrolyte is injected in a conventional manner, and the battery cell is formed at a specified charging current. Thereafter, electrolyte is replenished so that the amount of electrolyte reaches a target amount, for example, 110% of the height of the plate group, and supplementary charging is performed to produce a valve-regulated lead-acid battery.

[0038] Example 1 A flat terminal was prepared as shown in Figure 4, that is, a flat terminal with only one bend in the bent portion, a bend angle of 20 degrees for the entire inclined portion of the terminal and part of the terminal lead-out portion, and a lead-out portion with multiple bends. In this case, the length from the forming point of the flat terminal to the end of the welding side of the flat terminal was 4 mm. The thickness was 0.5 mm, the width was 4.4 mm, the total length was 28 mm, and the material was brass.

[0039] A positive electrode active material paste prepared according to a conventional method was filled into a lattice substrate mainly composed of lead for a positive electrode plate. On the other hand, a negative electrode active material paste prepared according to a conventional method and containing 1.0 mass% of carbon based on the amount of the negative electrode active material was filled into a lattice substrate mainly composed of lead for a negative electrode plate. Then, according to a conventional method, these were aged, dried, and chemically converted to prepare a positive electrode plate and a negative electrode plate. One positive electrode plate and two negative electrode plates were alternately stacked via a retainer mat mainly made of glass fiber, and the ears of the electrodes of the same polarity were connected by welding to form an electrode plate group. The theoretical capacity of the positive electrode active material at this time was 1.5 times the theoretical capacity of the negative electrode active material. Then, six of the electrode plate groups were assembled into a monoblock battery case 1 for each battery. Next, using the cast-on-strap method, the flat terminal 6, the battery case 1, the lid, and the lugs of the electrode plate group were welded with lead to both the positive and negative electrodes once each to form straps with the controlled lead-acid battery in an inverted state. One flat terminal was used for each of the positive and negative electrodes. The amount of lead used during welding was set to a thickness of 3.5 mm from the bottom when the battery was inverted. A total of 100 partially constructed controlled lead-acid batteries were created as described above.

[0040] After preparing 100 partially fabricated regulated lead-acid batteries, shallowly embedded batteries and good products were selected. In this case, a good product was selected if the forming point of the flat terminal 6 was embedded in the lead or the like used for welding, or if not embedded, if the length from the boundary between the bent part and the flat part to the boundary between the embedded part and the non-embedded part was less than 2.8 mm. A shallowly embedded battery was selected if the forming point was not embedded in the lead or the like used for welding, and the length from the forming point to the boundary between the embedded part and the non-embedded part was 2.8 mm or more. A good product is a regulated lead-acid battery in which, on one side of the flat terminal including side B, the length from one end of the flat terminal on the welding side to the forming point is 30% or more of the length from said one end to the boundary between the part welded with lead or lead alloy and the part not welded of the weld part. In addition, because the amount of lead was appropriate, in all valve-regulated lead-acid batteries, the length from one end of the flat terminal on the welded portion side to the boundary between the portion welded with lead or lead alloy and the portion not welded was less than 120% of the length from said end to the boundary between the bent portion and the flat portion. As a result, two of the batteries were found to be shallowly embedded. It should be noted that a valve-regulated lead-acid battery can be completed by passing the above-mentioned process through a partially manufactured regulated lead-acid battery. Specifically, the regulated lead-acid battery is turned upright, a dilute sulfuric acid electrolyte of a predetermined concentration is poured into it, and charging is performed to manufacture a 12V-2Ah valve-regulated lead-acid battery.

[0041] Example 2 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that flat terminals were used in which the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was 30 degrees instead of the angle shown in FIG. As a result, seven of the batteries were found to be shallowly embedded.

[0042] Example 3 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that flat terminals were used in which the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was set to 40 degrees instead of the angle shown in FIG. As a result, 15 of the batteries were found to be shallowly embedded.

[0043] Example 4 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that flat terminals were used in which the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was set to 50 degrees instead of the angle shown in FIG. As a result, 17 of the batteries were found to be shallowly embedded.

[0044] Example 5 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that flat terminals 6 were used in which the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was set to 15 degrees instead of the angle shown in FIG. As a result, five of the batteries were found to be shallowly embedded.

[0045] Example 6 5, the flat terminal had two bends, the angle between a part of the terminal lead-out portion and the plane between the bend closest to the end of the terminal lead-out portion on the welding side and the bend closest to the end of the terminal inclined portion was 10 degrees, the angle between the plane between the bend closest to the end of the terminal lead-out portion on the welding side and the bend closest to the end of the terminal inclined portion was 10 degrees and the bend angle between the part of the terminal inclined portion and the part of the terminal lead-out portion was 20 degrees, and 100 controlled lead-acid batteries were produced similar to those in Example 1. The distance between the bend closest to the end of the flat portion and the bend closest to the end of the weld was 2 mm. As a result, 10 of the batteries were found to be shallowly embedded.

[0046] Example 7 6, the flat terminal had two bends, the angle between a part of the terminal lead-out portion and a surface between the bend closest to the end of the terminal lead-out portion on the welding side and the bend closest to the end of the terminal inclined portion was 90 degrees, the angle between the surface between the bend closest to the end of the terminal lead-out portion on the welding side and the bend closest to the end of the terminal inclined portion was 70 degrees and the bend angle between the part of the terminal inclined portion and the part of the terminal lead-out portion was 20 degrees, and 100 controlled lead-acid batteries were produced similarly to Example 1. The distance between the bend closest to the end of the terminal lead-out portion and the bend closest to the end of the terminal inclined portion was 1.3 mm. As a result, eight of the batteries were found to be shallowly embedded.

[0047] Example 8 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that a flat terminal 6 was used in which the periphery of the forming point was curved and the bending angle of part of the terminal inclined portion and part of the terminal lead-out portion was 20 degrees, as shown in FIG. As a result, 10 of the batteries were found to be shallowly embedded.

[0048] Example 9 One hundred controlled lead-acid batteries were produced in the same manner as in Example 1, except that a flat terminal 6 was used, as shown in FIG. 8, having a hook on a part of the terminal lead-out portion and a bend angle of 20 degrees between a part of the terminal inclined portion and a part of the terminal lead-out portion. As a result, seven of the batteries were found to be shallowly embedded.

[0049] Comparative Example 1 100 controlled lead-acid batteries were produced in the same manner as in Example 1, except that the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was changed from that shown in FIG. 1 to 10 degrees. As a result, five of the batteries were found to be shallowly embedded, and 30 of the batteries were found to have lost contact with the strap, causing them to come off.

[0050] Comparative Example 2 100 controlled lead-acid batteries were produced in the same manner as in Example 1, except that the bending angle of the entire terminal inclined portion and part of the terminal lead-out portion was changed from that shown in FIG. 1 to 55 degrees. As a result, 20 of the batteries were found to be shallowly embedded.

[0051] <Consideration> In Comparative Examples 1 and 2, 20 or more shallowly embedded batteries were confirmed, which is more than the minimum value of 5 batteries in Examples 1 to 9. This is thought to be because the angle was outside the range of 20 degrees to 50 degrees proposed by the present invention, resulting in poor flow of lead or lead alloy during welding and poor embedding. In addition, Examples 6 and 7 show that the effect of the present invention can be obtained even when there are multiple bent portions. Furthermore, Examples 8 and 9 show that the effect of the present invention can be obtained even when all of the inclined portions of the terminal are not flat. From the above, it has been found that the valve regulated lead-acid battery having the configuration of the present invention can improve productivity. [Industrial Applicability]

[0052] According to the present invention, a valve-regulated lead-acid battery can be produced with improved productivity. [Explanation of symbols]

[0053] 1: Battery case 2: Partition wall 3: Cell Room 4: Plate group 4a: Positive ear group 4b: Negative ear group 5: Terminal holder 6: Flat terminal 6a: Terminal slope 6b: Terminal protrusion 6c: Forming point PS: Positive strap NS: Negative strap

Claims

1. A valve-regulated lead-acid battery comprising a battery case, at least one electrode group housed in at least one cell chamber provided in the battery case, and a strap connecting a positive electrode or a negative electrode lug group of the electrode group, A flat terminal connected to the strap is further provided. The up and down directions of the valve-regulated lead-acid battery when it is upright are called the upper and lower directions, The strap and the flat terminal are joined together such that the flat terminal extends below the strap; The flat terminal includes a terminal lead-out portion that extends to a joining portion for electrical connection with an external device, and a terminal inclined portion that is joined to the lug group, A valve regulated lead-acid battery, wherein a bending angle between the extension direction of the terminal lead-out portion and a part or all of the terminal inclined portion is 15 degrees or more and 50 degrees or less.

2. 2. The valve regulated lead-acid battery according to claim 1, wherein the bending angle is equal to or greater than 15 degrees and equal to or less than 40 degrees.

3. 3. The valve regulated lead-acid battery according to claim 1, wherein 30% or more of the entire inclined terminal portion is embedded inside the strap, and both sides of the embedded inclined terminal portion are bonded to the lead or lead alloy that forms the strap.

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