JP2007018753A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery capable of preventing leak current from leaking from an outer case 1 even if sea water or electrolytic liquid are leaked, by a simple constitution covering a metallic bellows leg 3 mounted on a lower end of the outer case 1 by a heat contraction tube 4. <P>SOLUTION: In the battery provided with a pressure levelling device 2 having a metallic bellows free in expansion and contraction communicating with inside of the metallic outer case 1 at lower end of the metallic outer case 1 housing a power generation element; and the metallic bellows leg 3 preventing the bellows of the pressure levelling device 2 from expansion of exceeding the prescribed length; at least a lower end part of the bellows leg 3 is covered by the heat contraction tube 4 having insulation property. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery in which a pressure equalizing device and a pressure equalizing device storage frame are attached to the lower end of a metal outer case that stores a power generation element.

  A conventional configuration example of a non-aqueous electrolyte secondary battery provided with a pressure equalizing device for use in a high-pressure environment such as the deep sea will be described. As shown in FIG. 2, this nonaqueous electrolyte secondary battery is a battery in which a power generation element is housed in a rectangular parallelepiped outer case 1 that is long in the vertical direction and is filled with a nonaqueous electrolyte and sealed. The outer case 1 is made of a stainless steel plate, and has upper and lower open ends of a rectangular cylinder 1a closed with a square lid plate 1b and a bottom plate 1c. Then, positive and negative terminals 1d protrude upward from the cover plate 1b of the exterior case 1, respectively.

  A pressure equalizing device 2 is attached to the lower surface of the bottom plate 1 c of the outer case 1. The pressure equalizing device 2 is formed of a bellows in which a thin stainless steel plate is formed in a cylindrical bellows shape so that the bellows can be expanded and contracted in the vertical direction. The inside of the bellows passes through an opening formed in the bottom plate 1c. It communicates with the inside of. Therefore, in the nonaqueous electrolyte secondary battery, when the external pressure increases, the bellows contracts to reduce the internal volume of the pressure equalizing device 2 to increase the internal pressure of the outer case 1 and to decrease the external pressure. In such a case, the bellows can be extended to increase the internal volume of the pressure equalizing device 2, thereby reducing the internal pressure of the exterior case 1, thereby achieving a balance with the external pressure.

  However, if the non-aqueous electrolyte secondary battery is provided with the pressure equalizing device 2 as described above, for example, when the internal pressure of the outer case 1 rises abnormally due to overcharging or the like, the bellows extends to the limit. There is a possibility that the non-aqueous electrolyte secondary battery will not fit in the storage location and may jump out upward. Therefore, the nonaqueous electrolyte secondary battery has a bellows leg 3 attached to the lower surface of the bottom plate 1c of the outer case 1 so as to surround the pressure equalizing device 2. This bellows leg 3 is a stainless steel plate frame comprising side plates 3a, 3a arranged on both sides of the pressure equalizing device 2, and a bottom plate 3b fixed between the lower ends of these side plates 3a, 3a. The upper ends of the side plates 3a and 3a are fixed to the bottom plate 1c of the outer case 1 by welding. Accordingly, when the internal pressure of the outer case 1 rises abnormally and the bellows of the pressure equalizing device 2 extends beyond a predetermined length, the lower end of the bellows comes into contact with the bottom plate 3b of the bellows leg 3 and tries to extend further. You can stop doing. In addition, this non-aqueous electrolyte secondary battery is provided with a safety valve 2a for releasing high-pressure gas when the internal pressure of the outer case 1 abnormally rises at the bottom of the bellows of the pressure equalizing device 2. A vent hole 3 c is formed in the bottom plate 3 b of the leg 3, and the bottom plate 3 b is positioned slightly above the lowermost end of the bellows leg 3. When such a vent hole 3c is formed, when the lower end of the bellows abuts against the bottom plate 3b and the safety valve 2a is opened due to an abnormal increase in the internal pressure of the outer case 1, a high pressure is passed through the vent hole 3c. Gas can be smoothly discharged to the outside.

  A plurality of the non-aqueous electrolyte secondary batteries are housed in an assembled battery case (not shown) and used as an assembled battery in the deep sea or the like. At this time, the non-aqueous electrolyte secondary batteries are arranged vertically on the bottom surface of the assembled battery case with the bellows legs 3 facing down. The assembled battery case is a box-shaped case having a rubber bladder at the bottom, and is filled with pressure equalizing oil and sealed. Therefore, when this assembled battery case is attached to a submersible craft or the like and dives into the deep sea, the rubber bladder of the assembled battery case bends inward due to water pressure, so that the high water pressure is applied to each non-aqueous electrolyte secondary battery via the pressure equalizing oil. The pressure equalizing device 2 is added.

  Here, the outer case 1 of the non-aqueous electrolyte secondary battery is made of a stainless steel plate and comes into contact with the electrolytic solution inside, so that it has the potential of the electrolytic solution. For this reason, the nonaqueous electrolyte secondary batteries housed in the assembled battery case need to insulate the exterior case 1 from each other. Therefore, these non-aqueous electrolyte secondary batteries are stored separately from each other by an insulating frame or an insulating material in the assembled battery case, or the surface of the outer case 1 or the bellows leg 3 is insulated by an insulating film or an insulating plate. Insulation was performed so as to cover with (see, for example, Patent Document 1).

  However, when seawater enters the battery case or the electrolyte leaks from the nonaqueous electrolyte secondary battery, the specific gravity of these seawater and electrolyte is higher than the pressure equalizing oil. It will accumulate at the bottom. For this reason, when seawater intrudes or electrolyte leaks, the bellows legs 3 fixed to the outer case 1 by welding come into contact with these seawater and electrolyte, so that they are isolated by an insulating frame or an insulating material. In addition, there has been a problem that leakage current flows between the outer cases 1 of the respective nonaqueous electrolyte secondary batteries. Even when the surface of the outer case 1 is covered with an insulating plate, the insulating plate only covers the outer surface of the bellows leg 3, so that the exposed portion of the inner stainless steel plate is in contact with seawater or electrolyte. If it does so, a possibility that a leak current may flow between the exterior cases 1 similarly arises. However, when the entire surface of the bellows leg 3 is covered with an insulating film such as an insulating paint, it is possible to maintain insulation between the exterior cases 1 even if such seawater or electrolyte accumulates at the bottom of the assembled battery case. it can. However, since non-aqueous electrolyte secondary batteries are exposed to extremely high pressures in the deep sea, there is a risk of the insulation film peeling off during repeated large pressure changes between normal pressure and high pressure. Since the non-aqueous electrolyte secondary battery is easily scratched only by rubbing, reliable insulation between the outer cases 1 could not be maintained even in this case.

The above problem is the same when a battery other than the nonaqueous electrolyte secondary battery is used, and the same problem occurs when a plurality of individual batteries are used side by side as well as when used as an assembled battery. Further, when only one battery is used, there is a problem that a leak current may flow between the wiring and the ground potential through seawater or an electrolyte.
JP 2003-51298 A

  In the present invention, since it is difficult to insulate the metal pressure equalizing device storage frame attached to the lower end of the metal outer case, leakage current does not flow out of the metal outer case due to seawater, electrolyte, or the like accumulated at the bottom. It tries to solve the problem of being unable.

  According to the first aspect of the present invention, an expandable / contractible pressure equalizing device communicating with the inside of the metal outer case and a metal pressure equalizing device housing for housing the pressure equalizing device are provided at the lower end of the metal outer case housing the power generating element. In the battery to which the frame is attached, at least the lower end portion of the pressure equalizing device storage frame is covered with an insulating resin film.

  According to the invention of claim 1, since the pressure equalizing device housing frame at the lower end of the battery is covered with the resin film, even if seawater or electrolyte accumulates at the installation location, the seawater and electrolyte are kept uniform. There is no risk of direct contact with the pressure device housing frame, and leakage current does not flow out of the metal outer case of the electrolyte potential. In particular, when a plurality of batteries are housed in an assembled battery case and used as an assembled battery, seawater that has entered from the outside and electrolyte that has leaked from the internal battery can easily collect at the bottom of the assembled battery case, and more than one When these batteries are connected in series, a large potential difference is generated between these metal outer cases, so that it is possible to reliably prevent leakage current by covering the pressure equalizing device housing frame with a resin film. In addition, since it is a resin film that covers the pressure equalizing device storage frame, even if a large pressure change is repeatedly received, the pressure equalizing device storage frame does not peel off.

  The pressure equalizing device storage frame needs to be attached so as to surround the pressure equalizing device below the metal outer case to support the heavy load of the metal outer case storing the power generation element. In addition, when this pressure equalizing device storage frame prevents the pressure equalizing device from expanding beyond a predetermined level, it is certain that the pressure equalizing device tries to expand with a strong force due to the high pressure inside the metal outer case. Sufficient strength is also necessary to prevent the damage. For this reason, it is difficult to construct the pressure equalizing device housing frame itself with an insulating material such as a weak resin.

  The resin film is preferably a heat shrinkable tube. As described above, when the heat shrink tube is used, the heat shrink tube having a sufficiently large diameter is externally fitted to the pressure equalizing device storage frame, and heat is applied to the pressure equalizing device storage frame so that the pressure equalizing device storage frame is almost adhered to the surface. This heat-shrinkable tube does not obstruct the operation of the pressure equalizing device or obstruct the installation of the battery.

  Hereinafter, the best embodiment of the present invention will be described.

  In the present embodiment, similarly to the conventional example, a non-aqueous electrolyte secondary battery used in an assembled battery for use in a high-pressure environment such as the deep sea will be described. As shown in FIG. 1, the non-aqueous electrolyte secondary battery has a pressure equalizing device 2 and a bellows leg 3 attached to the lower surface of a bottom plate 1c of a rectangular parallelepiped outer case 1 that is long in the vertical direction. Is exactly the same as the conventional non-aqueous electrolyte secondary battery shown in FIG. However, the outer case 1 can also be formed of an aluminum alloy, a titanium alloy, or the like. In FIG. 1 as well, the same reference numerals are given to constituent members having the same functions as those of the conventional example shown in FIG.

  As shown in FIG. 1, a heat-shrinkable tube 4 is placed on the bellows leg 3 of the nonaqueous electrolyte secondary battery of the present embodiment. That is, the bellows leg 3 is covered with the heat shrinkable tube 4 except for the upper ends of the side plates 3a and 3a and the entire bottom plate 3b. The bellows leg 3 is produced by fixing a bottom plate 3b horizontally by welding between lower ends of both side plates 3a, 3a which are vertically arranged with a gap therebetween. The heat-shrinkable tube 4 is fitted before the bellows leg 3 is attached to the bottom plate 1 c of the outer case 1. For this purpose, the cylindrical shape of the heat-shrinkable tube 4 having a sufficiently large diameter is first spread laterally, and the upper end of one side plate 3a of the bellows leg 3 is covered from above, and then the tip of the heat-shrinkable tube 4 is horizontally attached. From the bottom plate 3b to the vicinity of the upper end of the other side plate 3a. At this time, the end of the heat-shrinkable tube 4 is cut in advance so as to be positioned near the upper end of one side plate 3a. The heat shrinkable tube 4 is thermally contracted by applying heat, for example, by blowing hot air on the bellows leg 3 covered with the heat shrinkable tube 4. Then, the heat shrinkable tube 4 is in close contact with the surfaces of the side plates 3a and 3a and the bottom plate 3b of the bellows leg 3, so that it protrudes inside the bellows leg 3 and obstructs the vertical movement of the bellows of the pressure equalizing device 2. There is no need to stick out and get in the way when stored in a battery case. Moreover, the heat-shrinkable tube 4 is originally cylindrical and opens only at the upper end portions of the side plates 3a, 3a. Therefore, even if the lower end portion of the bellows leg 3 is immersed in seawater or an electrolyte, they can easily enter these. Will be able to prevent.

  However, as described above, when the safety valve 2a of the pressure equalizing device 2 is opened, the high-pressure gas cannot be smoothly discharged to the outside. That is, the internal pressure of the outer case 1 rises abnormally, the bellows of the pressure equalizing device 2 extends beyond a predetermined level, and the lower end of the bellows contacts the bottom plate 3b via the heat shrinkable tube 4, thereby opening the safety valve 2a. However, the high-pressure gas discharged from the safety valve 2a is blocked by the heat shrinkable tube 4 and cannot pass through the gas vent hole 3c. Therefore, as shown in FIG. 1, the heat shrinkable tube 4 is formed with an opening 4a at a portion corresponding to the central portion of the vent hole 3c of the bottom plate 3b. Then, the safety valve 2a is opened, and the high-pressure gas discharged from here is smoothly discharged to the outside through the opening 4a. Such an opening 4a is formed by, for example, heat shrinking the heat shrinkable tube 4 and then cutting out a portion that closes the gas vent hole 3c and sealing the peripheral edge of the cut with thermocompression bonding or an adhesive. be able to.

  The non-aqueous electrolyte secondary batteries are sequentially arranged in a vertical arrangement with the bellows legs 3 facing down on the bottom surface of a battery pack case (not shown). Next, wiring connection of each nonaqueous electrolyte secondary battery is performed in the upper end opening part of an assembled battery case. Then, the assembled battery is completed by filling the inside of the assembled battery case with pressure equalizing oil, covering the lid, and sealing.

  According to the above configuration, when seawater enters from the outside or the electrolyte flows out due to liquid leakage from any of the nonaqueous electrolyte secondary batteries, the seawater and the electrolyte are on the bottom surface of the assembled battery case. Even in the case where it accumulates, the bellows leg 3 in contact with the bottom surface is covered with the heat-shrinkable tube 4, so that it does not come into direct contact with these seawater and electrolyte. For this reason, a leak current does not flow from the outer case 1 of the nonaqueous electrolyte secondary battery through these seawater and electrolyte.

  When a large amount of seawater or electrolyte accumulates on the bottom surface of the assembled battery case and exceeds the portion covered by the heat shrinkable tube 4, the bellows legs 3 come into contact with these seawater and electrolyte, and thus the nonaqueous electrolyte 2 There is a risk of leakage current flowing between the outer cases 1 of the secondary batteries. However, when a large amount of seawater or electrolyte accumulates in this way, it can be easily detected by a water immersion sensor, a leak sensor, etc., so other measures such as stopping the use of the battery can be implemented. it can. In addition, in the case of the present embodiment, as shown in FIG. 1, before seawater or electrolyte contacts the bellows leg 3, the bellows made of stainless steel plate of the pressure equalizing device 2 is contacted. There is no point in covering only the legs 3 with the heat-shrinkable tube 4 to the top. Therefore, the heat-shrinkable tube 4 should cover at least the lower end portion of the bellows leg 3 at least.

  Moreover, in the said embodiment, although the case where the bellows leg 3 was covered with the heat contraction tube 4 was shown, the same effect can be acquired if it covers with the resin film which has insulation. That is, it is not always necessary to use a heat shrink resin, and it is not necessary to use a cylindrical resin film. For example, the bellows leg 3 is sandwiched between two sheet-like resin films or a two-folded sheet-like resin film, and the end edge portion can be reliably sealed by heat welding or the like. However, it is necessary to use such a resin film that has corrosion resistance to seawater or an electrolytic solution. In addition, if a resin film having sufficient heat resistance is used, the bellows leg 3 can be reliably insulated even when high-temperature high-pressure gas is discharged from the safety valve 2a, and leakage due to discharge of such high-pressure gas. Generation of current can be prevented.

  Moreover, in the said embodiment, although the safety valve 2a was provided in the bottom of the bellows of the pressure equalizing apparatus 2, and the gas vent hole 3c was formed in the bottom plate 3b of the bellows leg 3, although such a safety valve 2a was not provided, When the safety valve 2a is provided in another place such as the outer case 1, it is not necessary to form the gas vent hole 3c in the bottom plate 3b, so that the bellows leg 3 can be easily covered with the resin film. Become. Furthermore, in the said embodiment, although the case where the pressure equalization apparatus 2 which expands / contracts a bellows was used was shown, if the internal pressure of the exterior case 1 can be adjusted by expansion / contraction (expansion / contraction) of the volume including expansion / contraction. Any type of pressure equalizing device may be used.

  Further, in the above embodiment, the case where the bellows leg 3 composed of the side plates 3a, 3a and the bottom plate 3b is used has been described. However, for the purpose of preventing the expansion including the extension of the pressure equalizing device, and for protection, etc. Any metal pressure equalizing device storage frame configured to store the pressure device may be used.

  In the above embodiment, the case where a plurality of non-aqueous electrolyte secondary batteries are combined and used as an assembled battery has been described. However, each non-aqueous electrolyte secondary battery is separately or one non-aqueous electrolyte secondary battery. It is possible to implement the same in the case where only is used alone. And if it uses a pressure equalizing apparatus, it does not need to be an oil immersion type thing. Furthermore, although the said embodiment demonstrated the nonaqueous electrolyte secondary battery, the kind of this battery is not limited.

  Even if leakage of seawater, electrolyte, etc. occurs due to the simple structure of covering the metal pressure equalizing device storage frame attached to the lower end of the metal outer case with a resin film, leakage current flows out from the metal outer case. The remarkable effect that it can prevent reliably is acquired.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of the present invention and omitting a central portion in a vertical direction of a nonaqueous electrolyte secondary battery. It is a top perspective view which shows the prior art example and abbreviate | omitted the center part of the up-down direction of the nonaqueous electrolyte secondary battery.

Explanation of symbols

1 exterior case 2 pressure equalizing device 3 bellows leg 4 heat shrink tube

Claims (1)

  A battery in which an expandable / contractible pressure equalizing device communicating with the inside of the metal outer case and a metal pressure equalizing device housing frame for storing the pressure equalizing device are attached to the lower end of the metal outer case containing the power generation element A battery characterized in that at least the lower end of the pressure equalizing device housing frame is covered with an insulating resin film.

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