JP7024177B2 - Lead-acid battery and current collector - Google Patents

Description

The present disclosure relates to lead acid batteries and current collectors.

In recent years, power generation facilities using natural energy such as solar power and wind power have been actively installed to reduce CO ₂ . Since the timing of power generation cannot be controlled in these power generation facilities, storage battery equipment will be used together on the power generation side and / or the consumption side to level the power. Lead-acid batteries are often used as storage batteries for this purpose.

For example, Patent Document 1 discloses a lead-acid battery, particularly a positive electrode lattice thereof, in which the cross-sectional area of the vertical bone of the positive electrode grid frame is twice or more than twice the cross-sectional area of the transverse bone, and the compression ratio of the separator is 1. It is disclosed that the value is 1 or more.

Japanese Unexamined Patent Publication No. 10-18899

When a lead-acid battery is used for power leveling of power generation by natural energy as described above, this corresponds to a cycle application in which charging and discharging are repeated. In this case, the inventor of the present application has found that the life of a conventional lead-acid battery for cycling may be significantly shortened due to breakage of the current collector. Therefore, an object of the technique of the present disclosure is to provide a lead storage battery capable of maintaining a life even when used for the above-mentioned applications, and a current collector used therein.

In the study for solving the above-mentioned problems, the inventor of the present application has found that the conventional lead-acid battery for a cycle has a short life, particularly when used in a deep discharge depth range. For example, in a cycle life test at 25 ° C. with a DoD (Depth of Discharge) of 70%, the control valve lead acid battery (VRLA) for cycling had a very short life. Furthermore, it was discovered that the cause of this is that the positive electrode active material expands remarkably with the charge / discharge cycle, which causes stress on the vertical frame bone of the positive electrode lattice and causes the vertical frame bone to break at the grain boundary.

In view of the above, in the lead storage battery provided with the positive electrode current collector made of lead or a lead alloy according to the uniformity of the present invention, the positive electrode current collector includes the first and second horizontal frame bones and the first and second horizontal frame bones. An outer frame portion having a vertical frame bone, a plurality of inner bones provided intersecting the inside of the outer frame portion, and a position near the first vertical frame bone in the first horizontal frame bone, on the outside of the outer frame portion. It is provided with an integrally provided ear for collecting electricity. When the cross-sectional area of the vertical frame bone in the cross section perpendicular to the extending direction is S (mm ² ) and the thickness is t (mm), the relationship of S> t ^2/2 is satisfied, and the plurality of internal bones have a plurality of internal bones. Includes internal thick bone with a cross-sectional area greater than t2/ ⁴ in a cross section perpendicular to its extending direction. In addition, a square formed by the vertical frame bone and the inner bone without being crossed by the other inner bone, or a square formed by the vertical frame bone, the horizontal frame bone and the inner bone without being crossed by the other inner bone. For at least one of the squares that are not constructed, the volume of the square is V (mm ³ ), the length of the vertical frame bone of the part that constitutes the square is L (mm), and the width of the vertical frame bone is d (mm). ), The following formula (1),
(S × d) / (V × L ² ) ≧ 0.002 …… (Equation 1)
Satisfy the relationship represented by.

According to the lead storage battery and the current collector of the present disclosure, it is possible to suppress the breakage of the current collector and suppress the shortening of the life of the lead storage battery.

FIG. 1 is a schematic diagram illustrating a positive electrode current collector of a lead storage battery according to an embodiment of the present disclosure. FIG. 2 is a diagram further explaining the positive electrode current collector of FIG. FIG. 3 is a diagram showing the relationship between the parameters of the present disclosure and the number of life cycles of the lead storage battery and the number of fractured portions of the frame bone for the test battery according to the embodiment of the present disclosure. FIG. 4 is a diagram showing the relationship between the parameters of the present disclosure and the maximum lateral elongation rate of the positive electrode plate for the test battery according to the embodiment of the present disclosure. FIG. 5 is a diagram showing the relationship between the parameters of the present disclosure, the number of life cycles of the lead-acid battery, and the number of fractured portions of the frame bone for the other test batteries according to the embodiment of the present disclosure. FIG. 6 is a diagram showing the relationship between the parameters of the present disclosure and the maximum lateral elongation rate of the positive electrode plate for the other test batteries according to the embodiment of the present disclosure. FIG. 7 is a diagram illustrating a location where breakage of the vertical frame bone occurs in the positive electrode current collector of the lead storage battery. FIG. 8 is a diagram showing the ratio of the locations where breakage of the vertical frame bone occurs in the positive electrode current collector of the lead storage battery. FIG. 9 is a diagram showing an example of a positive electrode current collector of the lead storage battery according to the present disclosure. FIG. 10 is a diagram showing another example of the positive electrode current collector of the lead storage battery according to the present disclosure. FIG. 11 is a diagram showing still another example of the positive electrode current collector of the lead storage battery according to the present disclosure. FIG. 12 is a diagram showing still another example of the positive electrode current collector of the lead storage battery according to the present disclosure. FIG. 13 is a diagram showing still another example of the positive electrode current collector of the lead storage battery according to the present disclosure. FIG. 14 is a diagram showing a positive electrode current collector of a lead storage battery according to a modification of the embodiment of the present disclosure.

Hereinafter, the control valve type lead acid battery (VRLA) according to the embodiment of the present disclosure will be described with reference to the drawings.

The control valve type lead-acid battery of the present embodiment has a paste-type positive electrode plate and a negative electrode plate, a separator arranged between the positive electrode plate and the negative electrode plate to hold an electrolytic solution, and an electric tank for accommodating the positive electrode plate, the negative electrode plate and the separator. And.

The positive electrode plate and the negative electrode plate are formed by filling a lattice-shaped positive electrode current collector and negative electrode current collector made of lead or a lead alloy (Pb-Ca-based alloy, Pb-Ca-Sn-based alloy, etc.) with an active material paste. , Formed by aging and drying. Here, in the present specification, the active material refers to a plate obtained by removing a current collector from the electrode plate, and includes additives and the like. The active material is also referred to as an electrode material. For the separator, for example, an AGM parator composed of ultrafine glass fiber, silica powder, or the like is used, and the separator is impregnated with dilute sulfuric acid, which is an electrolytic solution. The electric tank is composed of, for example, a rectangular parallelepiped main body having an open side and a lid for closing the opening, and is, for example, an injection-molded thermoplastic. The configurations of the positive electrode plate, the negative electrode plate, the separator, and the electric tank can be appropriately selected according to the purpose and application.

(Structure of positive electrode current collector)
Next, the positive electrode plate included in the control valve type lead-acid battery of the present embodiment will be further described.

FIG. 1 is a diagram schematically showing a positive electrode current collector 10 constituting a positive electrode plate in the present embodiment. The positive electrode current collector 10 has an outer frame portion 15 configured in a rectangular shape, and a plurality of inner bones 24 provided intersecting the outer frame portion 15 and forming a grid together with the outer frame portion 15.

The outer frame portion 15 is composed of a first horizontal frame bone 11 and a second horizontal frame bone 12, and a first vertical frame bone 13 and a second vertical frame bone 14. At the end of the first horizontal frame bone 11 on the side of the first vertical frame bone 13, a current collecting ear portion 25 is provided so as to be integrated with the outside of the outer frame portion 15. Further, a foot portion 26 is provided on the outside of the second horizontal frame bone 12. In the present specification, the side provided with the selvage portion 25 for current collection in FIG. 1 may be referred to as "upper", and the side provided with the foot portion 26 may be referred to as "lower". Regarding this point and the description of "vertical" and "horizontal" of the horizontal frame bone 11, the vertical frame bone 13, etc., both are expressions for convenience, and the orientation when the positive electrode current collector 10 is used is limited. It's not a thing.

The internal bone 24 also includes a vertical internal bone 21 parallel to the vertical frame bones 13 and 14, and lateral internal bones 22 and 23 parallel to the horizontal frame bones 11 and 12. The lateral internal bone is divided into a lateral thick bone 22 and a thinner lateral fine bone 23 according to the difference in thickness. More specifically, when the thicknesses of the vertical frame bones 13 and 14 (dimensions in the direction perpendicular to the paper surface in FIG. 1) are t, the lateral internal bones 22 having a cross-sectional area exceeding t ^2/4 and the cross-sectional area are t. There is a transverse bone 23 that is less than ^2/4 . In the example of FIG. 1, both the longitudinal internal bone 21 and the lateral thick bone 22 are arranged at equal intervals inside the outer frame portion 15. Further, the lateral fine bones 23 are arranged at substantially equal intervals between the lateral thick bones 22 and between the lateral thick bones 22 and the first horizontal frame bone 11 or the second horizontal frame bone 12. The lateral fine bones 23 closest to the first horizontal frame bone 11 and the second horizontal frame bone 12 are spaced closer to each other than the other parts.

The positive electrode current collector 10 of this embodiment is manufactured by a casting method. That is, lead or a lead alloy may be formed as a material by using a mold corresponding to each bone thickness and arrangement described above.

Next, FIG. 2 is a diagram illustrating the configuration of the positive electrode current collector 10 in more detail. Here, I in FIG. 2 corresponds to an enlarged view of the vicinity of the upper right in FIG. However, in FIG. 2, only a smaller number of transverse bones 23 are shown. Further, the positive electrode current collector 10 in the illustrated range is viewed from the right (in the drawing) II (however, in addition to the vertical frame bone 14, the first horizontal frame bone 11, the lateral thick bone 22 and the lateral bone) The shape of the fine bone 23 is shown by a solid line so as to be seen through), and III, which is a diagram showing the cross sections of the vertical frame bone 14 and the vertical internal bone 21 when viewed from below, is also shown. The cross section of the horizontal frame bone 11 is hexagonal, and the cross section of the other bones is rhombic, but the cross section is not limited to this.

In the positive electrode current collector 10 of the present disclosure, the volume of the squares composed of bones including the vertical frame bones 13 or 14 and the length and cross-sectional area of the vertical frame bones 13 or 14 of the portions constituting the squares are predetermined. By having the above-mentioned relationship, it is possible to avoid a short life even when the product is used in a deep discharge depth range.

Specifically, a square composed of a second vertical frame bone 14, a longitudinal internal bone 21 closest to the second vertical frame bone 14, a first horizontal frame bone 11 and a lateral thick bone 22 closest to the first horizontal frame bone (in FIGS. 1 and 2). Consider the upper right square when considering the square that ignores the transverse bone 23). The volume of the square is V (cm ³ ), the width and cross-sectional area of the second vertical frame bone 14 are d (mm) and S (mm ² ), and the length of the second vertical frame bone 14 of the portion constituting the square is (Here, when the distance between the first lateral frame bone 11 and the lateral internal bone 22) is L (mm), the following equation (1)
(S × d) / (V × L ² ) ≧ 0.002 …… (Equation 1)
By configuring the positive electrode current collector 10 so as to satisfy the above conditions, it is possible to prevent the positive electrode current collector 10 and the lead storage battery from having a short life even when used in a deep discharge depth range.

The squares sandwiched between the first lateral frame bone 11 and the lateral thick bone 22 (corresponding to the "upper right" of the positive electrode current collector 10 in FIGS. 1 and 2) have been described. The same applies to the squares sandwiched between the thick bone 22 and the second horizontal frame bone 12, and the same applies to the side of the first vertical frame bone 13. For example, in FIG. 2, the lateral thick bone 22 closest to the first horizontal frame bone 11 and the next horizontal thick bone 22 (this interval is L'), the second vertical frame bone 14 and the closest vertical inner bone. Considering the squares composed of the bones 21, the following equation may be satisfied.

(S × d) / (V × L' ² ) ≧ 0.002
Further, the volume V of the square can be defined as, for example, in I of FIG. 2 which is a plan view, the product of the area surrounded by each bone constituting the square and the thickness t of the vertical frame bone 13. Here, the area of the square can be the area surrounded by the center line of each bone constituting the square. Further, when a bone having a hexagonal cross section is used as in the horizontal frame bone 11 shown in FIG. 2II, the bone is located at both ends in the thickness direction of the positive electrode current collector 10 and inside the square in the cross section of the bone. The inside of the square from the apex near it can be calculated as the volume of the square. When the same definition is applied to bones having a rhombic cross section (vertical frame bone 14, vertical internal bone 21, horizontal thick bone 22), a set of vertices located at both ends in the thickness direction of the positive electrode current collector 10 is used. Therefore, it means the center line of the bone.

Further, with respect to the vertical frame bones 13 and 14 and the vertical internal bone 21, the cross-sectional area refers to the cross-sectional area of the cross section perpendicular to the extending direction. Further, the widths of the vertical frame bones 13 and 14 refer to the dimensions of the horizontal frame bones 11 and 11 in the extending direction.

If the width or cross-sectional area of each bone is not uniform in the portion included in one square, the cross-sectional area and width in the central portion of the vertical frame bone in the length direction of the corresponding portion are used. This is because the stress applied to the bone is the largest in the central part, and the strength of this part is important.

Next, the reason why the fracture can be suppressed by satisfying the equation (1) is considered as follows.

First, the inventor of the present application has noticeably expanded the positive electrode active material with the charge / discharge cycle when used in a deep discharge depth range, whereby stress is applied to the bone of the positive electrode current collector 10 and the bone is granulated. It has been found that the field is broken. According to this finding, in the positive electrode current collector 10, the larger the volume of the square made of bone, the larger the dimensional change due to the expansion of the positive electrode active material, so that the stress applied to the bone becomes large and fracture is likely to occur. It will be.

Here, in the case of the inner bone 24, since the positive electrode active material is filled on both sides of each bone and exists, the stress associated with the expansion is applied from both sides of the inner bone 24 and is offset and reduced. On the other hand, as for the bone constituting the outer frame portion 15, since the positive electrode active material is present only inside the positive electrode current collector 10, the stress is not offset and the fracture is likely to occur unlike the inner bone 24.

The force against the stress applied to the frame bone (counterforce) varies depending on the width, cross-sectional area, and length of the vertical frame bones 13 or 14 constituting the square. When the width and cross-sectional area of the vertical frame bones 13 and 14 constituting the square are reduced or lengthened, the counterforce is reduced and fracture is likely to occur. Therefore, the volume of the squares and the width of the vertical frame bones 13 and 14 constituting the squares are cut so that the stress applied to the vertical frame bones 13 and 14 becomes small or the counterforce of the vertical frame bones 13 and 14 becomes large. Breaking can be suppressed by designing the area and length.

Further, in order to facilitate the flow of current from the selvage portion 25 of the current collector to the foot portion 26 side, the longitudinal internal bone 21 is composed entirely of thick bones, and the distance between the vertical internal bones 21 is larger than the distance between the lateral thick bones 22. Because it is arranged narrowly, the squares surrounded by the thick bones are vertically long rectangles. The thick bone refers to a bone having a cross-sectional area of more than t ^2/4 , specifically, the horizontal thick bone 22, the horizontal frame bones 11 and 12, and the vertical frame bones 13 and 14. The cross-sectional areas of the horizontal frame bones 11 and 12 and the vertical frame bones 13 and 14 are further large and exceed t ^2/2 .

As a result of the above, the vertical frame bone 13 or 14 is more likely to break under the influence of stress than the horizontal frame bone 11 or 12, so that the dimensions of the vertical frame bone 13 or 14 are important. Further, when the transverse bones 22 and the transverse fine bones 23 having different cross-sectional areas are provided, the positive electrode current collector 10 is easily broken for the transverse fine bones 23 having a cross-sectional area of t2 / ⁴ or less. The inventor of the present application has found that it does not affect (strength) (this will be described later). Therefore, in the formula (1) and the like, the squares are considered to include the lateral thick bone 22 regardless of the lateral fine bone 23. Also, consider squares that are not crossed by other large bones. For example, the second vertical frame bone 14, the second bone from the right of the vertical internal bone 21 in FIG. 1, the first horizontal frame bone 11, and the top bone of the horizontal thick bone 22 may also be used. Although it can be considered that a "square" is formed, the square is crossed by the rightmost bone of the longitudinal internal bone 21. Therefore, we do not consider such squares.

Next, a control valve type lead-acid battery was manufactured using the current collector 10 as described above.

First, lead powder and synthetic resin fibers were kneaded with water and sulfuric acid to obtain a paste for the positive electrode material. The paste of the positive electrode material was filled in a positive electrode current collector 10 which is a cast lattice made of a Pb—Ca—Sn alloy, and aged and dried to obtain an unchemical positive electrode plate.

Further, lead powder, synthetic resin fiber, shrink proofing agent, carbon black and BsSO ₄ were kneaded with water and sulfuric acid to prepare a paste for the negative electrode material. The paste of the negative electrode material was filled in a cast lattice made of a Pb—Ca—Sn alloy, and aged and dried to obtain an unchemical positive electrode plate.

Next, eight positive electrode plates and nine negative electrode plates were laminated via an extra-fine glass mat separator to form a group of electrode plates. The electrode plate group was stored in the electric tank by applying compression until the length reached the size in the electric tank. Pure lead was used as the added lead to form a positive electrode strap and a negative electrode strap connecting the same electrode plates, respectively. Here, instead of pure lead, a Pb—Sn-based alloy can be used for the strap.

After adhering the lid to the battery case, sulfuric acid was added as an electrolytic solution from the injection part of the lid, and the battery tank was chemical-generated to produce a control valve type lead-acid battery having a nominal capacity of 500 Ah (10 hR (time rate)) and 2 V. ..

Next, Table 1 shows the results of the cycle test for the test battery A manufactured as described above. The cycle test was conducted under the following conditions.
・ DoD 70% discharge: 25 ℃, 0.2CA × 3.5h
・ Normal charge: 25 ° C, 2.42 constant voltage (Imax = 0.2CA), charge electricity amount / discharge capacity = 1.02
・ Equal charge: 25 ° C, every 6 cycles, normal charge + 2.42V constant voltage (Imax = 0.2CA) x 8h
-Life judgment condition: When the discharge end voltage at the time of DoD 70% discharge falls below 1.7V.

In the positive electrode current collector of the test battery A, the distance between the lateral thick bones 22 and the distance between the horizontal frame bones 11 or 12 and the lateral thick bones 22 are both equally L. From A-1 to A-15 having a positive electrode current collector having a vertical frame bone thickness t of 6.0 mm and a width d, a cross-sectional area S, and a vertical frame bone length L of a portion constituting a square. Regarding the lead-acid battery, the relationship between the value of (S × d) / (V × L ² ) on the left side of the equation (1), the number of life cycles, the number of vertical frame bone breaks, and the maximum lateral elongation rate of the positive electrode plate. Shows.

As shown in Table 1, for A-1 to A-4 in which (S × d) / (V × L ² ) is smaller than 0.002, the vertical frame bone was broken at at least one place, and (S × d). ) / (V × L ² ), the larger the number of breaks. On the other hand, for A-5 to A-15 in which (S × d) / (V × L ² ) is 0.002 or more, there is no breakage of the vertical frame bone. This point and other results are shown in the graphs of FIGS. 3 and 4. As shown in FIG. 3, the number of fractured portions of the frame bone and the number of life cycles are extremely significantly improved when (S × d) / (V × L ² ) exceeds 0.002. Further, as shown in FIG. 4, (S × d) / (V × L ² ) is remarkably small in the vicinity of 0.002 with respect to the maximum lateral elongation rate of the positive electrode plate.

Table 2 shows the results of the cycle test for the other test battery B. As shown in FIGS. 1 and 2, the test battery B is also a VRLA using a positive electrode current collector 10 constituting a rectangular square, and is 200 Ah / 10 hR (+8 / -9 sheets (8 positive electrode plates and a negative electrode plate). 9 sheets) composition).

In the positive electrode current collector of the test battery B, the distance between the lateral thick bones 22 and the distance between the horizontal frame bones 11 or 12 and the lateral thick bones 22 are both equally L. For lead-acid batteries from B-1 to B-15 having a positive electrode current collector with t set to 3.8 mm and d, S, and L changed, the left side of the formula (1) is (S × d) / (V). The relationship between the value of × L ² ) and the number of life cycles, the number of vertical frame bone fractures, and the maximum lateral elongation rate of the positive electrode plate is shown.

As shown in Table 2, when (S × d) / (V × L ² ) is 0.002 or more, there is no breakage of the vertical frame bone. Further, as shown in the graphs of FIGS. 5 and 6, the number of vertical frame bone fractures and the number of life cycles are extremely significantly improved with the point where (S × d) / (V × L ² ) is 0.002 as a boundary. However, a remarkable improvement is also seen in the maximum lateral elongation rate of the positive electrode plate.

As described above, by satisfying the formula (1), the breakage in the positive electrode current collector 10 is remarkably suppressed, and the life of the lead storage battery is improved.

Further, as shown in Tables 1 and 2, and FIGS. 4 and 6, the following equation (2) is used.
(S × d) / (V × L ² ) ≧ 0.0032 …… (Equation 2)
By satisfying the above conditions, the lateral elongation of the positive electrode plate can be suppressed. Similarly, the following equation (3)
(S × d) / (V × L ² ) ≧ 0.0046 …… (Equation 3)
When the condition is satisfied, the lateral elongation of the positive electrode plate can be more reliably suppressed.

(About internal bones)
Next, it will be described that among the inner bones 24, the transverse fine bones 23 have no effect on the fragility of the positive electrode current collector 10.

This is shown in Table 3. Table 3 shows the same contents as those in Tables 1 and 2 for the test batteries C and D having 500 Ah / 10 hR (+8 / -9 sheets configuration), and shows the number of transverse bones 23 in the positive electrode current collector 10. Shows.

The test battery C has the same values as A-1 in Table 1 in terms of the values of t, d, L, S and V. In C1 to C-3, (S × d) / (V × L ² ) is 0.0011 (smaller than 0.002), so that the vertical frame bone is broken. Even if the number of transverse bones is increased to 16, 24, and 34, the number of breaks, the number of life cycles, and the maximum lateral elongation rate of the positive electrode plate are almost the same. There are many.

Further, the test battery D has the same values as A-12 in Table 1 in terms of the values of t, d, L, S and V. In D-1 to D-3, (S × d) / (V × L ² ) is 0.0077 (0.002 or more), so that the vertical frame bone is not broken. Further, even if the number of the transverse bones 23 is changed to 12, 18, and 28, there is almost no effect on the number of breaks, the number of life cycles, and the maximum lateral elongation rate of the positive electrode plate. In particular, even in the case of D-1, which has a smaller number of transverse bones 23 than in the case of C-1, which causes breakage, no breakage occurs.

In this regard, first, when a lead-acid battery is used (or a life test is performed), the positive electrode current collector 10 is gradually corroded. The transverse bone 23 is a thin bone provided mainly for facilitating the filling of the positive electrode current collector 10 with the paste of the active material, and is corroded within a relatively short period of time after the start of use of the lead storage battery. , It is considered that the strength of the positive electrode current collector 10 is not affected.

If the cross-sectional area of the transverse bone is t ^2/4 or less with respect to the thickness t of the vertical frame bone, it clearly does not affect the breakage of the positive electrode current collector 10. Therefore, the lateral thick bone 22 having a cross-sectional area exceeding t ^2/4 is used as an element constituting the square considered in the equation (1).

As described above, since the lateral fine bone 23 does not affect the fragility of the positive electrode current collector 10, only the lateral thick bone 22 is considered as the design of the positive electrode current collector 10 for suppressing the fracture. Just do it. It is desirable that the transverse bone 23 is also provided in the square considered in the formula (1) for the filling property of the paste of the active material, and its arrangement or the like can be designed separately from the fragility. .. This makes it possible to simplify the design of the positive electrode current collector 10.

(Location of breakage in positive electrode current collector)
Next, with reference to FIGS. 7 and 8, locations where breakage is likely to occur in the positive electrode current collector 10 will be described. FIG. 7 shows a electrode plate 50 manufactured by using the positive electrode current collector 10 of FIG. Here, the electrode plate 50 is divided into four equal parts in the vertical direction, and the regions A, B, C, and D are considered from the upper part to the lower part on the side of the selvage portion 25 for current collection (the side of the first horizontal frame bone 11). .. Similarly, consider the regions E, F, G, and H from the upper part to the lower part on the side opposite to the selvage portion 25 for current collection (the side of the second vertical frame bone 14). Since the positive electrode current collector 10 shown in FIG. 1 has three lateral thick bones 22 at equal intervals, the positions of the horizontal thick bones 22 coincide with the boundaries between the regions. However, the position of the lateral thick bone 22 is not defined as the boundary between the regions. Therefore, when the lattice shape, for example, the number and arrangement of the horizontal thick bones 22 is different (for example, FIGS. 10 to 12 described later), the boundary between the regions and the position of the horizontal thick bones 22 are different.

Here, with respect to the first and second vertical frame bones 13 and 14 in the battery of A-1 shown in Table 1 (equipped with eight positive electrode current collectors 10), the fracture points are represented by A to H in FIG. The distribution is as shown in the graph of FIG. Obviously, from FIG. 8, the fracture is most in the region E, that is, the square on the uppermost side (side of the first horizontal frame bone 11) and far from the selvage portion 25 for current collection (on the side of the second vertical frame bone 14). It is occurring a lot. Further, the lower side (the side of the foot portion 26) has less breakage, and if the height is the same (A and E, B and F, etc.), the breakage is more frequent on the side far from the current collecting ear portion 25.

Therefore, by setting so as to surely satisfy the equation (1) in the portion where the fracture is particularly frequent, the fracture of the vertical frame bone can be sufficiently suppressed even if the equation (1) is not satisfied in the other portions. can. Further, if it is not necessary to satisfy the formula (1) for the portion where breakage is unlikely to occur, the filling amount of the active material paste relative to the positive electrode current collector 10 can be increased.

The positive electrode current collector 10 based on this idea is illustrated as a schematic diagram in FIGS. 9 to 13. In these figures, the first and second horizontal frame bones 11 and 12, the longitudinal internal bone 21, and the horizontal thick bone 22 are simply shown as lines, and the illustration of the horizontal fine bone 23 is omitted.

In the case of FIG. 9, as compared with the case of FIG. 1, the first horizontal frame bone 11 and the horizontal thick bone 22 next to it (first) so as to connect only the second vertical frame bone 14 and the vertical internal bone 21 next to it. An additional lateral thick bone 22a is provided between the vertical frame bone 13 and the lateral thick bone extending from the second vertical frame bone 14. As a result, the region E in FIG. 7, which is most likely to break, can be divided into two half-sized squares to reduce the value of V so that Equation 1 can be satisfied.

Next, in the case of FIG. 10, as compared with the case of FIG. 1, the additional lateral thick bone 22b (in the horizontal thick bone extending from the first vertical frame bone 13 to the second vertical frame bone 14) near the first horizontal frame bone 11. Yes, the structure is the same as that of the lateral thick bone 22). As a result, the regions A and E in FIG. 7 can be divided into two half-sized squares to reduce the value of V so that Equation 1 can be satisfied.

Next, in the case of FIG. 11, the lateral thick bone 22 is increased as compared with the case of FIG. 1, and the distance between the first horizontal frame bone 11 and the horizontal thick bone 22 is increased from the side of the first horizontal frame bone 11. 2 It becomes wider in order toward the side of the horizontal frame bone 12. As a result, the squares on the side of the first horizontal frame bone 11 can be more reliably satisfied with the equation 1.

In the case of FIG. 12, the number of the lateral thick bones 22 is larger than that of the lower half (the side of the second lateral frame bone 12) for the upper half (the side of the first lateral frame bone 11), and the squares are formed. Is made smaller. Thereby, the equation 1 can be satisfied for the upper square. The lateral thick bone 22 may be arranged so as to form several rows of small squares from the upper side, not limited to the upper “half”.

In the case of FIG. 13, the distance between the two vertical frame bones 13 and 14 and the vertical internal bone 21 closest to each is narrower than the distance between the vertical internal bones 21. As a result, for the squares having the vertical frame bones 13 and 14 as a part of the configuration, the vertical frame bones 13 and 14 are not included while suppressing the breakage of the vertical frame bones 13 and 14 by satisfying the equation (1). The filling amount of the active material paste can be increased for the squares composed of (for example, two lateral thick bones 22 and two longitudinal internal bones 21).

In addition to the above, breakage can be suppressed by adjusting the size of the squares to satisfy the equation (1), especially at the locations where breakage is likely to occur shown in FIGS. 7 and 8. .. It should be noted that FIGS. 9 to 13 show a schematic structure and do not show an absolute dimensional relationship or the like. Further, there is no problem even if the formula (1) is satisfied except for the squares (those containing the vertical frame bones 13 or 14 as components) that are described as satisfying the formula (1). Further, the configurations of FIGS. 9 to 13 can be used in various combinations.

(Modification example)
In the above, the positive electrode current collector 10 in which the longitudinal internal bone 21 is parallel to the vertical frame bones 13 and 14 and the lateral internal bones 22 and 23 are parallel to the horizontal frame bones 11 and 12 has been described. However, it is not limited to this. FIG. 14 shows a modified positive electrode current collector 10a. In the positive electrode current collector 10a, the outer frame portion is composed of the first horizontal frame bone 11 and the second horizontal frame bone 12, the first vertical frame bone 13 and the second vertical frame bone 14, and the horizontal thick bone 22. It is the same as the positive current collector 10 shown in FIG. 1 in that the lateral fine bone 23, the current collecting ear portion 25, and the foot portion 26 are provided.

On the other hand, in the positive electrode current collector 10a of FIG. 14, the vertical internal bone 31 is not parallel to the vertical frame bones 13 and 14, but from the side of the current collecting ear portion 25 from the upper side to the lower side. It is installed diagonally so as to move away.

Also in this case, if the square including a part of the vertical frame bone 13 or 14 is satisfied with the formula (1), the breakage of the vertical frame bone 13 or 14 can be suppressed.

The “squares” in this case are illustrated in FIG. For example, the square 41 in FIG. 14 is a part composed of a part of the second vertical frame bone 14, the first horizontal frame bone 11, two adjacent vertical internal bones 31, and the horizontal thick bone 22. In FIG. 14, it is shown in an elongated pentagonal shape. The squares 42 and 43 are a part composed of a part of the second vertical frame bone 14 or a part of the first vertical frame bone 13, two adjacent vertical internal bones 31, and a lateral thick bone 22. ..

Similar to the positive current collector 10 in FIG. 1, the width and cross-sectional area of the first or second vertical frame bone 13 or 14 are d (mm) and S (mm ² ), and the volume of the square 41 is Va (cm ³ ). ), Assuming that the length of the second vertical frame bone 14 of the portion constituting the square 41 is La, the equation (1) is (S × d) / (Va × La ² ) ≧ 0.002.
By designing to satisfy this, it is possible to suppress the breakage of the vertical frame bone.

For the squares 42 and 43, the breakage of the vertical frame bone is suppressed by satisfying the formula (1) for the respective volumes Vb and Vc and the lengths Lb and Lc of the vertical frame bone of the corresponding portion. be able to.

Even in the positive electrode current collector 10a, the vertical internal bones 31 are parallel to each other, but this is not essential, and may be arranged radially, for example. Further, it is not essential that the lateral thick bones 22 are parallel to the first horizontal frame bones 11 and the second horizontal frame bones 12, or the lateral thick bones 22 are parallel to each other. Further, it is not essential that both the longitudinal internal bone and the lateral internal bone are linear, and a curved line may be drawn. In any case, if the square including the first or second vertical frame bone 13 or 14 is satisfied with the formula (1), the breakage of the vertical frame bone in the square can be suppressed.

Further, in the above, the positive electrode current collector formed by casting has been described as an example, but the present invention is not limited to this, and it may be formed by another method such as a punched lattice. Further, although the VRLA battery has been described as an example, the present invention is not limited to this, and it can also be used for a liquid battery or the like.

According to the lead-acid battery and the current collector of the present disclosure, shortening of the life can be suppressed, so that it is particularly useful as a lead-acid battery that can be used for a long period of time even when used in a deep discharge depth range.

10 Positive current collector 10a Positive current collector 11 1st horizontal frame bone 12 2nd horizontal frame bone 13 1st vertical frame bone 14 2nd vertical frame bone 15 Outer frame part 21 Vertical internal bone 22 Horizontal thick bone 22a Additional horizontal thick Bone 22b Additional lateral thick bone 23 Lateral fine bone 24 Internal bone 25 Current collecting ear 26 Foot 31 Vertical internal bone 41 Square 42 Square 43 Square 50 Pole plate

Claims (7)

Equipped with a positive electrode current collector made of lead or lead alloy,
The positive electrode current collector has an outer frame portion having first and second horizontal frame bones and first and second vertical frame bones, and a plurality of inner bones provided intersecting inside the outer frame portion. And, at a position closer to the first vertical frame bone in the first horizontal frame bone, a current collecting ear portion integrally provided on the outside of the outer frame portion is provided.
When the cross-sectional area of the vertical frame bone in the cross section perpendicular to the extending direction is S (mm ² ) and the thickness is t (mm), the relationship of S> t ^2/2 is satisfied.
The plurality of internal bones include an internal thick bone having a cross-sectional area of more than t ^2/4 in a cross section perpendicular to the extending direction.
A square formed by the vertical frame bone and the inner thick bone without being crossed by the other inner thick bone, or another inner thick by the vertical frame bone, the horizontal frame bone and the inner thick bone. For at least one of the squares formed without being crossed by the bone, the volume of the square is V (cm ³ ), the length of the vertical frame bone of the portion constituting the square is L (mm), and the vertical frame. When the width of the bone is d (mm), the following formula (1),
(S × d) / (V × L ² ) ≧ 0.002 …… (Equation 1)
Satisfy the relationship represented by
The plurality of internal bones further include internal bones having a cross-sectional area of t2 / ⁴ or less.
A lead-acid battery characterized in that the inner fine bone is provided inside the square . In the lead storage battery of claim 1,
A lead-acid battery characterized in that the square formed by the first horizontal frame bone, the second vertical frame bone, and the inner thick bone satisfies the formula (1). In the lead storage battery of claim 2,
A lead-acid battery characterized in that the square formed by the first horizontal frame bone, the first vertical frame bone, and the inner thick bone satisfies the formula (1). In the lead storage battery according to any one of claims 1 to 3,
The square including the second vertical frame bone is a lead storage battery, which satisfies the formula (1). In the lead-acid battery according to any one of claims 1 to 4.
The lead-acid battery comprises at least one of a vertical bone parallel to the vertical frame bone and a horizontal bone parallel to the horizontal frame bone. In the lead-acid battery according to any one of claims 1 to 5 .
The following formula (2),
(S × d) / (V × L ² ) ≧ 0.0032 …… (Equation 2)
A lead-acid battery characterized by satisfying the relationship represented by. An outer frame portion having first and second horizontal frame bones and first and second vertical frame bones, a plurality of inner bones provided intersecting the inside of the outer frame portion, and the first horizontal frame. A current collecting ear portion integrally provided on the outside of the outer frame portion is provided at a position close to the first vertical frame bone in the bone.
When the cross-sectional area of the vertical frame bone in the cross section perpendicular to the extending direction is S (mm ² ) and the thickness is t (mm), the relationship of S> t ^2/2 is satisfied.
The plurality of internal bones include an internal thick bone having a cross-sectional area of more than t ^2/4 in a cross section perpendicular to the extending direction.
A square formed by the vertical frame bone and the inner bone without being crossed by the other inner bone, or the vertical frame bone, the horizontal frame bone and the inner bone to the other inner bone. For at least one of the squares formed without being crossed, the volume of the square is V (cm ³ ), the length of the vertical frame bone of the portion constituting the square is L (mm), and the length of the vertical frame bone is L (mm). When the width is d (mm), the following formula (1),
(S × d) / (V × L ² ) ≧ 0.002 …… (Equation 1)
Satisfy the relationship represented by
The plurality of internal bones further include internal bones having a cross-sectional area of t2 / ⁴ or less.
A current collector characterized in that the inner microbone is provided inside the square .

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