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EP-4012832-B1 - BATTERY

EP4012832B1EP 4012832 B1EP4012832 B1EP 4012832B1EP-4012832-B1

Inventors

  • WAKIMOTO, RYOICHI

Dates

Publication Date
20260506
Application Date
20200623

Claims (5)

  1. A battery comprising: an electrode body (3) obtained by stacking a positive electrode plate (4) and a negative electrode plate (5) with a separator interposed therebetween; an exterior body (1) having an opening and housing the electrode body (3); a sealing plate (2) sealing the opening; and an external terminal (7, 9) attached to the sealing plate (2), a tab (40, 50) being provided at at least one of the positive electrode plate (4) or the negative electrode plate (5) and being electrically connected to the external terminal (7, 9) via a current collector (6a, 6b, 8a, 8b) between the electrode body (3) and the sealing plate (2), the tab (40, 50) being welded to the current collector (6a, 6b, 8a, 8b), a covering member (81, 82) covering a welding point (60a, 60b, 61a, 61b) between the tab (40, 50) and the current collector (6a, 6b, 8a, 8b); wherein the electrode body (3) includes a first electrode body element (3a) and a second electrode body element (3b), each including the positive electrode plate (4) and the negative electrode plate (5), the first electrode body element (3a) includes a first tab group (40A1, 50A1) of tabs each being the tab (40, 50), the second electrode body element (3b) includes a second tab group of tabs (40A2, 50A2) each being the tab (40, 50), each of the first tab group (40A1, 50A1) and the second tab group (40A2, 50A2) is welded to the current collector (6a, 6b, 8a, 8b), and the covering member (81, 82) covers a first welding point (60a, 60b) between the first tab group (40) and the current collector (6a, 6b) and a second welding point (61a, 61b) between the second tab group (50) and the current collector (8a, 8b), and extends to an area between the first welding point (60a, 60b) and the second welding point (61a, 61b); characterized in that the current collector (6a, 6b, 8a, 8b) includes a liquid inlet (15) for injecting an electrolyte into the exterior body (3), and the liquid inlet (15) has, at the electrode body (3), an opening (11a) spaced apart from and covered with the covering member (81).
  2. The battery of claim 1, wherein the current collector (6a, 6b, 8a, 8b) includes a first current collector (6a, 8a) and a second current collector (6b, 8b), the first current collector (6a, 8a) is welded to the tab (40, 50), and a part of the second current collector (6b, 8b) is covered with the covering member (80, 81), wherein the second current collector (6b, 8b) is electrically connected to the external terminal (7, 9).
  3. The battery of claim 1, wherein the liquid inlet (15) includes an insulating tubular member (11b) projecting toward the electrode body (3).
  4. The battery of claims 1 to 3, wherein a gap (87) through which the electrolyte passes is interposed between the current collector (6a, 6b, 8a, 8b) and a peripheral edge of the covering member (80, 81) covering the opening (11a) of the liquid inlet (15) at the electrode body (3).
  5. The battery of claims 1 to 4, wherein the covering member (80, 81) covering the opening (11a) of the liquid inlet (15) at the electrode body (3) has, at a point other than a point directly above the opening (11a), a hole through which the electrolyte passes.

Description

TECHNICAL FIELD The present invention relates to a battery. BACKGROUND ART Batteries such as alkaline secondary batteries and nonaqueous electrolyte secondary batteries are used for purposes such as driving power sources for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV), and stationary rechargeable battery systems for reducing output fluctuations in solar or wind power generation, for example, and for peak-shifting grid power to be stored at night and used in the daytime. A foreign object may be mixed into such a battery while being assembled. In particular, a metal foreign object mixed into a battery may cause an internal short circuit. The internal short circuit has the following mechanism. First, adhering to a positive electrode material, a metal foreign object is, as metal ions, dissolved into an electrolyte by a high potential of the positive electrode. After reaching a negative electrode, the metal ions precipitate as a metal. The metal precipitates to grow toward the positive electrode, break through a separator, and come into contact with the positive electrode, thereby causing an internal short circuit. Secondary batteries are usually assembled in a cleanroom to reduce foreign objects such as metal foreign objects mixed into the batteries. In addition, the metal foreign objects attached to an electrode body during the assembly are removed by air blowing, suction, magnetic force adsorption, or wiping with a polishing tape, for example. Patent Document 1 suggests a sealed battery obtained by inserting an electrode body into a bag-shaped porous body, and inserting, into a sealed container, the porous body with the electrode body inserted thereinto. In addition, Patent Document 2 discloses a rectangular secondary battery. CITATION LIST PATENT DOCUMENT Patent Document 1: Japanese Unexamined Patent Publication No. 2009-87812Patent Document 2: Japanese Unexamined Patent Publication No 2019-009015 SUMMARY OF THE INVENTION Patent Document 1 fails to specifically describe any method or advantage of interposing the porous body between the electrode body and the lid of the sealed container. The specific method is unknown. In addition, the used porous body is a bag, which consumes the active material and the battery capacity. In view of the foregoing background, it is an objective of the present invention to provide a battery capable of effectively reducing foreign objects mixed into an electrode body, without reducing the battery capacity. A battery of the present invention includes, as recited in claim 1, an electrode body obtained by stacking a positive electrode plate and a negative electrode plate with a separator interposed therebetween, an exterior body having an opening and housing the electrode body, a sealing plate sealing the opening, and an external terminal attached to the sealing plate. A tab is provided at at least one of the positive electrode plate or the negative electrode plate, and is electrically connected to the external terminal via a current collector between the electrode body and the sealing plate. The tab is welded to the current collector. A covering member covers a welding point between the tab and the current collector. The electrode body includes a first electrode body element and a second electrode body element, each including the positive electrode plate and the negative electrode plate. The first electrode body element includes a first tab group of tabs each being the tab. The second electrode body element includes a second tab group of tabs each being the tab. Each of the first tab group and the second tab group is welded to the current collector. The covering member covers a first welding point between the first tab group and the current collector and a second welding point between the second tab group and the current collector, and extends to an area between the first welding point and the second welding point. In a preferred embodiment, the current collector includes a first current collector and a second current collector. The first current collector is welded to the tab. A part of the second current collector is covered with the covering member, wherein the second current collector is electrically connected to the external terminal. The current collector includes a liquid inlet for injecting an electrolyte into the exterior body. The liquid inlet has, at the electrode body, an opening spaced apart from and covered with the covering member. The phrase "at the electrode body, an opening spaced apart from and covered with the covering member" means that the opening is covered with the covering member and that the opening is spaced apart from the current collector covering member. The liquid inlet can include an insulating tubular member projecting toward the electrode body. In one preferred embodiment, a gap through which the electrolyte passes is interposed between the current collector and a peripheral edge of the cover