JP2012009332A - Secondary battery - Google Patents

Abstract

An object of the present invention is to reduce the strength of a container that houses a power generation element, and when the container divided into a plurality of chambers breaks due to an increase in internal pressure, the internal pressure rises in the damaged part. Provided is a secondary battery that is limited to a portion corresponding to a chamber and can suppress scattering of fragments and electrolyte.
A secondary battery includes a plurality of electrode plate groups, an electrolyte solution, and a container that stores the electrode plate group and the electrolyte solution. The interior of the container 1 is divided into a plurality of storage chambers 22 by partition walls. The partition wall includes an upper side wall 44 made of a pair of plate-like portions and a lower side wall 20. The upper part of the lower side wall 20 is inserted between the pair of plate-like parts to form a hardly breakable part.
[Selection] Figure 2

Description

  The present invention relates to a secondary battery having a scattering suppression mechanism that suppresses scattering of fragments and electrolytic solution of a container when a container that houses a power generation element is damaged due to an increase in internal pressure.

  Secondary batteries such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries can be used repeatedly by charging, so they are widely used in in-vehicle power supplies, portable electronic device power supplies, and power storage equipment power supplies. ing. As described above, as the usage range of the secondary battery is expanded, misuse that erroneously uses the charging method and the usage method also increases. If overcharge or reverse connection is made due to misuse, the electrolyte may leak or the battery may be damaged depending on the type of secondary battery.

  Therefore, in particular, when a secondary battery such as a lithium ion battery is used as a power source for portable electronic devices, it is often used as a battery pack in which one or a plurality of secondary batteries are packed. Battery packs are specialized in shape, capacity, etc. as a power source for specific models, and the charging device is designed to prevent overcharging and reverse connection according to the charging characteristics of the specific battery pack. Incorporated functions. Therefore, when the secondary battery is used as a battery pack, the risk of leakage during charging and battery damage is extremely low.

  On the other hand, for example, lead storage batteries, nickel metal hydride batteries, nickel cadmium batteries, etc. used as automobile batteries are not used as power sources for specific models in the form of battery packs, but should be used in various models. It is often required to be versatile. For this reason, in order to avoid misuse such as overcharging and reverse connection in these secondary batteries, it is necessary to rely on battery cases and methods that call attention by clearly indicating the charging method and usage method on the lid. I don't get it.

  Therefore, a secondary battery such as a lead-acid battery that is not used as a battery pack should be equipped with a mechanism for minimizing the damage caused by leakage or damage to the container due to misuse. Is desirable.

  In relation to this point, Patent Documents 1 to 3 propose that a thin-walled portion is provided on the lid, such as by cutting out the inner surface of the lid of the lead-acid battery case. According to these proposals, when the container is filled with gas due to overcharge or the like, and the internal pressure rises due to a chemical reaction of the gas and the container is damaged, the thin portion is first broken. Therefore, at an early stage when the internal pressure rises, the gas inside the container is released to the outside, and the energy for damage is reduced. Therefore, it is possible to prevent the container from being greatly damaged, and to prevent the fragments and electrolyte solution of the container from being scattered widely.

Japanese Utility Model Publication No. 63-135760 Japanese Patent Laid-Open No. 54-1111639 Japanese Utility Model Publication No. 2-120750

  However, many secondary batteries such as lead-acid batteries are divided into several independent chambers. When a thin-walled portion as in Patent Document 1 is provided on the lid of such a secondary battery, when the thin-walled portion breaks due to an increase in the internal pressure of one chamber, portions corresponding to several chambers of the thin-walled portion are There is a possibility that the chain breaks. As a result, the cover is damaged in a wide range, and the electrolyte contained in some chambers may be scattered. Therefore, it is conceivable that the degree of debris and electrolyte scattering increases. Furthermore, if such a thin portion is provided on the lid, the strength of the lid may be reduced, and the lid may be easily destroyed by an impact such as dropping.

  Therefore, the present invention does not reduce the strength of the container that houses the power generation element, and when the container whose interior is divided into a plurality of chambers is damaged by an increase in internal pressure, It is intended to be limited to the part corresponding to the chamber where the rise. Thereby, the secondary battery which can suppress scattering of a fragment and electrolyte solution can be provided.

The present invention provides a plurality of electrode plate groups each having a positive electrode plate, a negative electrode plate, and a separator, an electrolytic solution, a container that stores the plurality of electrode plate groups and the electrolyte solution, and a plurality of housings inside the container. A secondary battery comprising at least one partition wall divided into chambers,
The plurality of storage chambers each store at least one of the electrode plate group and the electrolyte solution,
The container has a gas holding part that holds gas inside at an upper part than the liquid level of the electrolyte solution,
The partition relates to a secondary battery having a hard-to-break part in a part adjacent to the gas holding part.

  According to the secondary battery of the present invention, when the container whose interior is divided into a plurality of chambers is damaged due to an increase in internal pressure, the portion to be damaged is limited to the portion corresponding to the chamber in which the internal pressure has increased, Spattering of fragments and electrolyte can be suppressed. Further, the strength of the container that houses the power generation element is not reduced.

It is a perspective view which shows the external appearance of the secondary battery which concerns on one Embodiment of this invention. FIG. 2 is a perspective view showing an internal structure of the secondary battery of FIG. 1 with a lid removed from a case and a part of the lid cut away. FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. 2. It is an expanded sectional view of the characteristic part of the rechargeable battery concerning other embodiments of the present invention. It is an expanded sectional view of the characterizing portion of the rechargeable battery concerning other embodiments of the present invention. It is an expanded sectional view of the characterizing portion of the rechargeable battery concerning other embodiments of the present invention.

  The secondary battery according to the present invention includes a plurality of electrode plate groups each including a positive electrode plate, a negative electrode plate, and a separator, an electrolyte solution, a plurality of electrode plate groups, a container containing the electrolyte solution, and a plurality of interiors of the container. And at least one partition wall that is divided into storage chambers. Each of the plurality of storage chambers stores at least one electrode plate group and an electrolytic solution. The container has a gas holding unit that holds gas inside at an upper part than the liquid level of the electrolytic solution. The partition wall has a hard-to-break part in a part adjacent to the gas holding part.

  The container is often damaged due to an increase in internal pressure because the gas filled in the gas holding part of the container causes a chemical reaction and the gas inside the container expands due to the reaction heat. In a secondary battery in which the interior of the container is divided into several storage chambers, a chemical reaction occurs at first in only one storage chamber. However, if the partition wall that divides each storage chamber breaks, the reaction sequentially propagates to other storage chambers.

  In the secondary battery of the present invention, when a chemical reaction occurs in any of the storage chambers, a hard-to-break part is provided in a part of the partition adjacent to the gas holding part, which is most easily subjected to the greatest force. . For this reason, even if a reaction occurs inside one of the storage chambers and a portion of the storage body corresponding to the storage chamber is damaged, it is avoided that the partition walls are broken due to the presence of the hard-to-break portion. be able to.

  Therefore, it is possible to prevent a reaction from being induced in another adjacent storage chamber, and it is possible to minimize damage to the storage body. As a result, not only the scattering of the fragments can be suppressed, but also the electrolytic solution can be prevented from scattering from the plurality of storage chambers. Therefore, scattering of the electrolytic solution can be suppressed.

  In the secondary battery according to one aspect of the present invention, the container includes a rectangular case having an opening and a lid that seals the opening. The partition includes a lower side wall supported by the case and an upper side wall supported by the lid. The upper side wall includes a pair of plate-like portions arranged at a predetermined interval. The hard-to-break part is formed by a pair of plate-like parts and the upper part of the lower side wall inserted therebetween.

  According to the above configuration, the lower wall has a simple structure similar to that of a conventional secondary battery, and only the upper wall has a plate structure having a double structure different from the conventional one. A hard-to-break part can be formed. Therefore, it is possible to suppress scattering of fragments and electrolyte without particularly increasing the cost.

  In addition, by providing a hard-to-break part in the part adjacent to the gas holding part of the partition wall, the thickness of the lower side wall substantially corresponding to the part below the liquid level of the electrolyte (liquid holding part of the container), It is also possible to make the thickness (for example, 1 to 1.5 mm) smaller than the thickness of the conventional partition wall (for example, 2 to 3 mm). Therefore, it is possible to increase the substantial volume of the liquid holding part, and the battery capacity can be easily increased. In addition, generally a partition is formed from materials, such as a polypropylene, a high density polyethylene, a polystyrene, an acrylic resin, a styrene resin, and an ABS resin.

  In the secondary battery according to another embodiment of the present invention, the distance between the pair of plate-like portions is made 0.2 to 5 mm larger than the thickness of the upper portion of the lower side wall, and the upper end portion of the lower side wall is joined to the lid. Thereby, a difficult-to-break part is formed.

  In this way, the distance between the pair of plate-like portions is set to be 0.2 mm or more larger than the thickness of the upper portion of the lower side wall, so that the upper end portion of the lower side wall and the lid are bonded by adhesion or an adhesive. Thus, it becomes easy to insert a jig for joining (for example, a hot plate for welding) between the plate-like portion and the lower side wall. On the other hand, by preventing the distance between the pair of plate-like portions from exceeding 5 mm more than the thickness of the upper portion of the lower side wall, the pair of plate-like portions and the upper portion of the lower side wall are prevented from functioning as hard-to-break parts. can do. This is because if the distance between the pair of plate-like portions becomes too large, the integrity of the pair of plate-like portions and the upper portion of the lower side wall will be reduced, and they will not reinforce each other.

  Furthermore, according to the said structure, a moderate margin arises between a pair of plate-shaped part and a lower side wall. Therefore, when a chemical reaction occurs inside the gas holding part, the impact transmitted to the lower side wall can be reduced. Therefore, the breakage of the partition wall can be effectively prevented.

  In the secondary battery according to still another embodiment of the present invention, the upper portion of the lower side wall inserted between the pair of plate-like portions is joined to the lid and the pair of plate-like portions. Thereby, a pair of plate-shaped part and the upper part of a lower side wall are integrated, and a hard-to-break part with large intensity | strength can be formed. Moreover, the sealing property between each accommodating chamber can be improved.

  In the secondary battery according to still another embodiment of the present invention, the hard-to-break part includes a thick part in which the partition wall is partially thickened. With this configuration, it is not necessary to use a material having a particularly high strength in order to form the hard-to-break part, and the hard-to-break part can be easily formed. Therefore, since a difficult-to-break part can be formed with the same material conventionally used for the partition inside a secondary battery, the raise of cost can be suppressed.

  At this time, it is preferable that the thickness of the thick part is 100 to 400% larger than the thickness (for example, 2 to 3 mm) of the other part of the partition wall. By setting the lower limit to 100% or more, breakage of the partition walls can be effectively prevented. By making the upper limit 400% or less, it is possible to prevent the weight of the secondary battery from increasing unnecessarily.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a perspective view showing a secondary battery according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the internal structure of the secondary battery. FIG. 3 shows an enlarged sectional view taken along line III-III in FIG. In FIG. 2, the case and the lid are partially cut away to improve the internal visibility.

  The battery 10 in the illustrated example includes a case 16 having a square shape and an opening on the top side, and a lid (sealing body) 18 that closes the opening of the case 16. The case 16 and the lid 18 constitute the housing 1 that houses the power generation element of the battery 10. The power generation element includes a plurality of electrode groups 24 and an electrolytic solution made of a sulfuric acid aqueous solution (not shown), for example. Each of the electrode groups 24 includes a positive electrode, a negative electrode, and a separator interposed therebetween.

  The case 16 and the lid 18 are made of an insulator. Examples of the insulator include polypropylene, high density polyethylene, polystyrene, acrylic resin, styrene resin, ABS resin, and the like.

  The case 16 is generally filled with an electrolyte so that the liquid level is 70 to 80% of the depth H thereof. A portion of the container 1 above the liquid surface of the electrolytic solution is a gas holding portion 1a that holds a gas such as air inside. Therefore, the “part adjacent to the gas holding part” of the partition wall is, for example, above the boundary with the position of 0.6H to 0.9H as the boundary from the bottom of the partition wall, where the depth of the case is H. Refers to the part.

  The gas holding part 1a is a part where the gas generated during overcharging or reverse connection is filled, and is a part that is very easily damaged when the filled gas undergoes a chemical reaction.

  On the other hand, the part below the liquid level of the electrolyte solution of the container 1 is a liquid holding part 1b that holds the electrolyte solution inside. The liquid holding portion 1b is a portion that is not easily damaged by the chemical reaction even when the container 1 is damaged, and is relatively difficult to be damaged.

  The interior of the container 1 is divided into a predetermined number (six in the illustrated example) of cell chambers 22. Each cell chamber 22 accommodates an electrode group 24 and an electrolyte. Between adjacent cell chambers 22, each electrode group 24 is connected in series via a strap 26 and a connection portion 28. In the electrode group 24 accommodated in the cell chambers 22 at both ends of the case 16, each positive electrode or negative electrode is connected to the positive or negative electrode poles 30 and 32.

  A predetermined number (five in the illustrated example) of the lower side walls 20, which are part of the partition walls 46 that partition the cell chambers 22, are formed inside the case 16. The same material as that used for the case 16 and the lid 18 described above can be used for the lower wall 20. Moreover, the composite material which reinforced those materials with the fiber and the metal can also be used.

  The lid 18 has a substantially rectangular top plate portion 18a and a leg portion 18b having a predetermined height provided so as to bend the outer peripheral portion of the top plate portion 18a vertically downward. The top plate portion 18a of the lid 18 is provided with a pair of electrode terminals 34 and 36 connected to the pole columns 30 and 32, respectively. The electrode terminals 34 and 36 are respectively installed in positions near both ends of the top plate portion 18a in the longitudinal direction X in the top view of the container 1 and biased to one side in the width direction Y in the top view of the container 1. Yes. In addition, an opening for replenishing the electrolyte in each cell chamber 22 (electrolyte replenishment) so as to be arranged at equal intervals parallel to the longitudinal direction X at a position biased to the other side in the width direction Y in the top plate portion 18a. Hole) 38 is provided. The electrolyte replenishment hole 38 is sealed with a stopper 40.

  Further, the lid 18 is formed with an upper side wall 44 composed of a pair of plate-like portions 42 arranged in parallel at predetermined intervals at positions corresponding to the lower side walls 20 on the lower surface of the top plate portion 18a. . The lid 18 seals the opening of the case 16 by welding the lower end of the leg 18 b to the upper end of the opening of the case 16.

  The partition wall 46 is formed by inserting the upper portion of the lower side wall 20 between the pair of plate-like portions 42 and welding the upper end portion of the lower side wall 20 to the lower surface of the top plate portion 18 or bonding it with an adhesive. 46 is formed. That is, the partition wall 46 is composed of the lower side wall 20 and the upper side wall 44.

  And the overlapping part of a pair of plate-shaped part 42 and the upper part of the lower side wall 20 forms the difficult-to-break part 48 which is hard to fracture | rupture rather than the other part of the partition 46. Here, the space | interval L2 of a pair of plate-shaped part 42 is 0.2-5 mm larger than the thickness L1 of the lower side wall 20, More preferably, it is enlarged only 1-2 mm.

  For example, the thickness of the plate-like portion 42 can be 1 to 6 mm. For example, the width of the plate-like portion 42 (height from the lower surface of the top plate portion 18a) can be set to 20 to 80 mm. The plate-like portion 42 can be made of the same material as that of the top plate portion 18a or can be made of a material different from that of the top plate portion 18a. A composite material in which the material of the case 16 and the lid 18 is reinforced with fibers or metal can also be used.

  Here, as shown in FIG. 3, the vertical width of the pair of plate-like portions 42 is set so that the lower end portion of the upper side wall 44 is positioned slightly below the normal liquid surface S of the electrolytic solution. By doing so, it is possible to avoid that the reaction energy when the chemical reaction occurs inside the gas holding portion 1a directly reaches the lower wall 20. Therefore, it is possible to prevent the partition wall 46 from being broken at a single portion of the lower side wall 20.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described.

  In FIG. 4, the characteristic part of the secondary battery which concerns on Embodiment 2 is shown with the partially expanded sectional view of a secondary battery. In the second embodiment, the upper side wall 50 is formed from a pair of plate-like portions 42, a partition wall 52 is formed by the upper side wall 50 and the lower side wall 20, and the upper portion of the lower side wall 20 is inserted between the pair of plate-like portions 42. Thus, the second embodiment is the same as the first embodiment in that the hard-to-break portion 54 is formed.

The second embodiment is different from the first embodiment in that a pair of plate-like portions 42 are arranged in parallel at an interval substantially equal to the thickness L1 of the upper portion of the lower side wall 20.
Furthermore, the second embodiment differs from the first embodiment not only in that the upper end portion of the lower side wall 20 is joined to the lower surface of the top plate portion 18 but also in contact with the pair of plate-like portions 42 at the upper portion of the lower side wall 20. This is the point in which the portion being connected is joined to the pair of plate-like portions 42.

  Thus, not only the lower side wall 20 is joined to the lid 18 but also a pair of plate-like parts, so that the integrity of the lower side wall 20 and the upper side wall 50 is increased, and the strength of the hard-to-break part 54 is increased. Can be increased. These joints can be made by welding and adhesion by an adhesive as in the first embodiment. The material of the upper side wall 50 and the lower side wall 20 is the same as that of the first embodiment.

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described.

  In FIG. 5, the characteristic part of the secondary battery which concerns on Embodiment 3 is shown with the partially expanded sectional view of a secondary battery. In the third embodiment, each partition wall 60 of the secondary battery includes a thick upper side wall 62 and a normal thickness lower side wall 56.

  The thick upper side wall 62 is formed so as to reach the normal liquid level S from the lower surface of the top plate portion 18b, and the lower end portion thereof is joined to the upper end portion of the lower side wall 56 by welding or the like. In the present embodiment, the thick upper side wall 62 alone constitutes a difficult-to-break part. Here, the thickness of the upper side wall 62 is made 100 to 400% larger than the lower side wall 56. For example, if the thickness of the lower side wall 56 is 2 to 3 mm, the thickness of the upper side wall 62 is 4 to 15 mm. The materials of the lower side wall 56 and the upper side wall 62 are the same as those in the first embodiment.

In this way, by forming the hardly-breakable portion with the thick upper wall 62, it is possible to form the hardly-breakable portion with the same material as that of the conventional lid, and to simply increase the thickness of the upper portion of the partition wall. Thus, it is possible to form a difficult-to-break part at low cost.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described.

  In FIG. 6, the characteristic part of the secondary battery which concerns on Embodiment 4 is shown with the partial expanded sectional view of a secondary battery. In the fourth embodiment, the secondary battery does not include the upper side wall, and the partition wall is configured only by the lower side wall 58.

  The lower wall 58 has a high-strength portion 58a in the upper portion, and the upper end portion thereof is joined to the lower surface of the top plate portion 18b by welding or the like. The high-strength portion 58a constitutes a difficult-to-break portion. Here, the high-strength portion 58a is formed of a material having a higher strength (tensile strength) than the other portion 58b of the lower side wall 58.

  As an example of the material of the high-strength portion 58a, a composite material in which materials used for the case 16 and the lid 18 are reinforced with fibers or metal can be cited.

As a specific method for forming the high-strength portion 58a on the lower side wall 58, when the high-strength portion 58a is formed from a resin material, the above-described high-strength material is applied to the upper end of the other portion 58b of the lower side wall 58. It can be considered that the high-strength portion 58a is formed by integral molding. The high-strength portion 58a may be bonded to the upper end of the other portion 58b by welding or an adhesive.
When a metal material is used for the high-strength layer 58a, insert molding may be considered so that the metal plate is integrated with the lower side wall 58. The thickness of the high-strength portion 58a may be the same as or different from the other portions 58b.

  The secondary battery of the present invention is useful, for example, when a secondary battery is used as an in-vehicle power source, a driving power source for various portable electronic devices, and a power source in a power storage facility. In particular, it is useful in a secondary battery such as a lead storage battery in which safety is left to the user's usage without being packed.

DESCRIPTION OF SYMBOLS 1 ... Container 10 ... Battery 16 ... Case 18 ... Lid | cover 20, 56, 58 ... Lower side wall 42 ... Plate-shaped part 44, 50 ... Upper side wall 46, 52, 60 ... Partition 48, 54 ... Hardly breakable part 62 ... Thickness Part 58a ... high-strength part

Claims (6)

A plurality of electrode plate groups each having a positive electrode plate, a negative electrode plate, and a separator, an electrolytic solution, a container that stores the plurality of electrode plate groups and the electrolyte, and an interior of the container are divided into a plurality of storage chambers. A secondary battery comprising at least one partition wall,
Each of the plurality of storage chambers stores at least one of the electrode plate group and the electrolyte;
The container has a gas holding part that holds gas inside at an upper part than the liquid level of the electrolyte solution,
A secondary battery, wherein the partition wall has a hard-to-break part in a part adjacent to the gas holding part. The container includes a rectangular case having an opening, and a lid that seals the opening.
The partition includes a lower side wall supported by the case and an upper side wall supported by the lid,
The upper side wall includes a pair of plate-like portions arranged at a predetermined interval,
The secondary battery according to claim 1, wherein the hard-to-break portion is formed by the pair of plate-like portions and an upper portion of the lower side wall inserted therebetween.   The secondary of claim 2, wherein an interval between the pair of plate-like portions is larger by 0.2 to 5 mm than a thickness of an upper portion of the lower side wall, and an upper end portion of the lower side wall is joined to the lid. battery.   The secondary battery according to claim 2, wherein the upper part of the lower side wall inserted between the pair of plate-like parts is joined to the lid and the pair of plate-like parts.   The secondary battery according to claim 1, wherein the hard-to-break portion includes a thick portion in which the partition wall is partially thickened.   The secondary battery according to claim 5, wherein a thickness of the thick portion is larger by 100 to 400% than other portions of the partition wall.

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