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EP-4254549-B1 - LEAD-ACID BATTERY

EP4254549B1EP 4254549 B1EP4254549 B1EP 4254549B1EP-4254549-B1

Inventors

  • OBAYASHI, Chihiro

Dates

Publication Date
20260506
Application Date
20211028

Claims (10)

  1. A lead-acid battery (1) comprising at least one cell including an element (11) and an electrolyte solution, wherein the element (11) includes a negative electrode plate (3), a positive electrode plate (2), and a bag-shaped separator (4) interposed between the negative electrode plate (3) and the positive electrode plate (2), the negative electrode plate (3) includes a negative current collector and a negative electrode material, the positive electrode plate (2) includes a positive current collector and a positive electrode material, the positive current collector contains Sn, and the bag-shaped separator (4) includes a rib protruding toward the positive electrode plate (2), and houses the positive electrode plate (2), characterised in that the negative electrode material contains a polymer compound having a repeating structure of oxy C 2-4 alkene units.
  2. The lead-acid battery (1) according to claim 1, wherein a content of the polymer in the negative electrode material is 5 ppm or more on a mass basis.
  3. The lead-acid battery (1) according to claim 1 or 2, wherein the content of the polymer in the negative electrode material is 550 ppm or less on a mass basis.
  4. The lead-acid battery (1) according to any one of claims 1 to 3, wherein a content of Sn in the positive current collector is 0.5 mass% or more.
  5. The lead-acid battery (1) according to any one of claims 1 to 4, wherein the content of Sn in the positive current collector is less than 3 mass%.
  6. The lead-acid battery (1) according to any one of claims 1 to 5, wherein the polymer compound contains at least one selected from the group consisting of a hydroxy compound having a repeating structure of oxy C 2-4 alkylene units, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound, and the hydroxy compound is at least one selected from the group consisting of a poly C 2-4 alkylene glycol, a copolymer having a repeating structure of oxy C 2-4 alkylene, and a poly C 2-4 alkylene oxide adduct of a polyol.
  7. The lead-acid battery (1) according to claim 6, wherein the polymer compound contains the hydroxy compound, and the hydroxy compound has a repeating structure of oxypropylene units.
  8. The lead-acid battery (1) according to claim 6, wherein the polymer compound has one or more hydrophobic groups, and at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.
  9. The lead-acid battery (1) according to claim 6 or 8, wherein the polymer compound contains at least one selected from the group consisting of the etherified product and the esterified product, and each of the etherified product and the esterified product has a repeating structure of oxyethylene units.
  10. The lead-acid battery (1) according to claim 9, wherein the polymer compound has an HLB of 4 or more and 9 or less.

Description

TECHNICAL FIELD The present invention relates to a lead-acid battery. BACKGROUND ART Lead-acid batteries are in use for various applications, including automotive and industrial applications. The lead-acid batteries include a negative electrode plate, a positive electrode plate, a separator (or mat), an electrolyte solution, and the like. Each electrode plate includes a current collector and an electrode material. An additive may be added to constituent members of the lead-acid battery from the viewpoint of imparting various functions to a lead-acid battery. Patent Document 1 proposes a lead-acid battery in which an electrolyte solution and/or an electrode active material molded product contain a polymer compound containing any one selected from the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid or an ester thereof having a polymerization degree of 30 or more and 3000 or less, or the polymer compound and colloidal barium sulfate particles. Patent Document 2 proposes a negative electrode plate for a lead-acid battery in which a current collector is filled with a paste-type active material containing an expander, polyoxyperfluoroethylene phenylamine represented by a specific chemical formula is used as the expander, and the polyoxyperfluoroethylene phenylamine is contained in at 0.005 to 3 wt% with respect to the paste-type active material. As the separator, not only a sheet- or mat-shaped separator, but also a bag-shaped separator may be used. For example, Patent Document 3 proposes a lead-acid battery in which a positive electrode plate obtained by filling a paste-like active material into a grid of a lead-calcium-tin (Pb-Ca-Sn) alloy containing calcium (Ca) at 0.05 to 0.07 wt% and tin (Sn) at 0.75 to 1.0 wt% is housed in a bag-shaped separator obtained by folding a microporous polyethylene film in a U shape, providing vertically parallel ribs on the inner side, and performing pressure-bonding with irregularities provided at both left and right ends in a mechanical manner. PRIOR ART DOCUMENT PATENT DOCUMENTS Patent Document 1: JP-A-2000-149981Patent Document 2: JP-A-9-147874Patent Document 3: JP-A-5-307949 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION A positive current collector is elongated by corrosion as charge-discharge of a lead-acid battery is repeated. Therefore, if a positive electrode plate is housed in a bag-shaped separator, the life is exhausted by a short circuit associated with damage to the separator. In particular, in a high temperature cycle test, the elongation of the positive current collector is significant, and therefore life performance is considerably deteriorated when the positive electrode plate is housed in the bag-shaped separator. Meanwhile, it has become evident that when the positive electrode plate is housed in the bag-shaped separator, life performance in a deep discharge cycle test is improved. MEANS FOR SOLVING THE PROBLEMS The present invention relates to a lead-acid battery including at least one cell including an element and an electrolyte solution, in which the element includes a negative electrode plate, a positive electrode plate, and a bag-shaped separator interposed between the negative electrode plate and the positive electrode plate,the negative electrode plate includes a negative current collector and a negative electrode material,the positive electrode plate includes a positive current collector and a positive electrode material,the negative electrode material contains a polymer compound having a repeating structure of oxy C2-4 alkylene units,the positive current collector contains Sn, andthe bag-shaped separator includes a rib protruding toward the positive electrode plate, and houses the positive electrode plate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially cutaway exploded perspective view showing an appearance and an internal structure of a lead-acid battery according to one aspect of the present invention. MODE FOR CARRYING OUT THE INVENTION In a deep discharge cycle test in which charge-discharge including deep discharge is repeated, stratification is likely to proceed in which a specific gravity of an electrolyte solution in an upper portion of a lead-acid battery decreases and the specific gravity of the electrolyte solution in a lower portion of the lead-acid battery increases. If the stratification proceeds, lead sulfate is likely to accumulate in the lower portion of an electrode plate. If the accumulation of lead sulfate becomes significant, a phenomenon in which the accumulated lead sulfate is hardly reduced even when charge is performed (sulfation). Meanwhile, since a charge-discharge reaction is likely to occur on an upper side of the electrode plate, softening of the positive electrode material becomes remarkable in a portion on the upper side of the positive electrode plate. As a result, the life of the lead-acid battery is reduced. It is effective to reduce a diff