JP3381060B2 - Battery pack - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof structure in which an outer casing has a gas vent hole and a waterproof seal at the bottom, and an anode terminal plate and a cathode terminal plate at the ceiling, and at least one battery is housed inside. For example, the present invention relates to a battery pack to be installed in a wireless device, and more particularly to a battery pack capable of ensuring sufficient safety.

[0002]

2. Description of the Related Art Conventionally, in a structure in which a battery pack of this type is completely enclosed by an outer casing, for example, when one battery is short-circuited, the temperature inside the battery pack rises, which causes the internal pressure to rise. There was a risk of the outer casing exploding.

In order to solve this problem, in an outer casing 101 for accommodating two batteries 2 and 3 shown in FIG. 8, an anode terminal plate 4 and a cathode terminal plate 5 are provided on the ceiling part, while the center of the bottom part is provided. In the portion, a gas vent hole 102 penetrating the bottom portion is provided for venting the internal gas. Normally, the vent hole 1
The outlet of 02 is closed by a waterproof seal 103, and when the internal pressure of the outer casing 101 rises, the waterproof seal 103 is peeled off and gas inside is released to prevent the battery pack from bursting.

On the other hand, even a single battery is provided with a safety valve in order to prevent the battery from bursting when the internal pressure rises. In the case of a battery, the electrolyte inside may leak out from the safety valve when the safety valve is activated due to an increase in internal pressure. If the electrolyte is flammable, the leaked electrolyte may cause a fire.

[0005]

In the above-mentioned conventional battery pack, when the safety valve of the battery housed inside operates and the electrolyte flows out, the gas vent hole of the battery pack penetrates the bottom portion. However, there is a problem that the electrolyte of the battery leaks from the gas vent hole to cause a disaster to the surroundings due to the failure of the battery and the increase of the internal pressure.

An object of the present invention is to solve the above problems and to prevent the battery from bursting even if the internal pressure rises, and to allow the electrolytic solution of the battery to leak from the outer casing to the outside. It is to provide a battery pack that can ensure safety by preventing it.

[0007]

In a battery pack according to the present invention, an outer casing has a gas vent hole and a waterproof seal at the bottom and an anode terminal plate and a cathode terminal plate at the ceiling portion, and at least one battery is housed inside. In an explosion-proof battery pack, the battery has a safety valve
It is placed inside the casing toward the bottom and the safety
Height position where the amount of electrolyte leaking from the valve accumulates at the bottom of the outer casing
And is characterized in that said none from the bottom a cylindrical shape extending in the ceiling direction and the through-hole of greater outer casing from the position of the safety valve comprises a gas vent pipe to the vent holes. Due to such a structure of the gas vent pipe, the electrolytic solution leaking from the battery is collected at the bottom inside the outer casing and is difficult to flow out from the gas vent hole.

Further, it is characterized in that a hygroscopic material is provided in the inner bottom portion of the outer casing in the vicinity of the safety valve of the battery. As a result,
The electrolyte that has leaked from the battery is absorbed by this hygroscopic material, so that it is prevented from flowing out through the gas vent hole.

Further, the outer casing is characterized in that it has a degassing ceiling pipe that extends inward from the ceiling portion toward the bottom portion and locates the degassing pipe with a gap inside, and is further attached to the ceiling portion of the ceiling pipe. A moisture absorbent is provided as a ceiling moisture absorbent. With this structure, even if the leaked electrolytic solution flows along the degassing pipe, it is absorbed by the ceiling hygroscopic material before flowing into the degassing hole, and the leakage can be more severely prevented.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. Here, in the case of a single battery to be used, if an overcurrent flows due to an accident such as a short circuit and the temperature inside the battery rises and the internal pressure exceeds a predetermined value, the safety valve opens and the internal electrolyte is ejected. This will prevent the battery from bursting and ensure safety.

FIG. 1 is an explanatory view of an inner structure showing a first embodiment of the present invention in a sectional form.

In the battery pack shown in FIG. 1, two batteries 2 and 3 are housed inside an outer casing 1 which is a waterproof case with the anodes facing the bottom. The batteries 2 and 3 are assumed to have a safety valve for ejecting the electrolytic solution on the anode side. In the outer casing 1,
An anode terminal plate 4 and a cathode terminal plate 5 are provided in the ceiling portion, and a gas vent pipe 7 having a gas vent hole 6 as a through hole is provided in the bottom portion. The degassing pipe 7 is the outer casing 1.
It is provided at a gap position between the cells 2 and 3 from the center of the bottom portion to the ceiling portion at a predetermined height. During normal use, the gas vent hole 6 is closed by a waterproof seal 8 outside the bottom of the outer casing 1. However, when the inner pressure of the outer casing 1 rises, the waterproof seal 8 is peeled off, so that the gas inside passes through the gas vent hole 6 and is discharged to the outside of the outer casing 1.

One of the differences from the conventional battery pack shown in FIG. 8 is the installation direction of the battery, and in all the built-in batteries, the anode side having the safety valve for ejecting the electrolytic solution is located at the bottom of the outer casing. That is what the side is doing. Another difference is that the gas vent hole not only penetrates the bottom of the outer casing, but also a gas vent pipe having a certain height from the bottom of the outer casing. is there. Therefore, when the bottom of the outer casing is oriented toward the ground, even if the electrolyte leaks from the battery, it collects in the bottom and unless the amount of the collected electrolyte exceeds the height of the gas vent pipe, It is possible to avoid the outflow of the electrolytic solution.

Next, further effective means for preventing the outflow of the electrolytic solution will be described with reference to the second embodiment of the present invention shown in FIG.

2 is different from FIG. 1 in that a moisture absorbent 9 is provided in the bottom of the outer casing 1 in the vicinity of the anode surface having the safety valves of the batteries 2 and 3. Therefore, the electrolytic solution ejected from the safety valves of the batteries 2 and 3 is absorbed by the hygroscopic material 9. As the hygroscopic material 9, a material having air permeability and compatible with the properties of the electrolytic solution such as a polymer absorbing polymer is selected. The configuration other than the hygroscopic material 9 is the same as that of FIG. 1, and the same components are assigned the same reference numerals and the description thereof will be omitted.

Therefore, only the electrolytic solution which has been ejected from the batteries 2 and 3 and which has not been completely absorbed by the hygroscopic material 9 reaches the degassing hole 6, which makes it more difficult to flow out the electrolytic solution.

Next, referring to FIG. 3 and FIG. 4 together, FIG.
A configuration capable of further ensuring safety than the battery pack shown in FIG. FIG. 3 is an explanatory view of the inner structure showing the third embodiment of the present invention in a sectional form, and FIG. 4 is a perspective view for explaining the arrangement of the inner constituent elements with the separator removed from FIG. The connection cord is omitted in FIGS. 3 and 4. 3 and 4, the same components as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

As shown, the difference from FIG. 2 is that
The batteries 2 and 3 and the degassing pipe 1 with respect to the outer casing 10.
Separator 12 for positioning 1 and degassing pipe 1
1 is provided with a ceiling pipe 13 forming a double structure. The ceiling pipe 13 has a structure that covers the periphery of the gas vent pipe 11 and the ceiling opening portion on the ceiling of the outer casing 10 with a gap for degassing. Further, a ceiling hygroscopic material 14 made of the same material as the hygroscopic material 9 is provided on the inner ceiling portion of the ceiling pipe 13 so as to absorb the electrolytic solution crawling outside the gas vent pipe 11.

Therefore, the electrolytic solution which has not reached the moisture absorbing material 9 and reaches the gas vent hole 6 is absorbed by the ceiling moisture absorbing material 14, so that the electrolytic solution hardly flows out from the gas vent hole 6.

Although the gas vent pipe 11 has a structure which penetrates the bottom of the outer casing 10 unlike FIG. 2, it may be molded together with the bottom of the outer casing so long as it provides the same function. For example, the shape, combination, etc. are free and are not limited to the illustrated structure. The separator 12 is set at a predetermined location on the outer casing 10 by the separator joint portion 15.

Further, FIG. 4 shows one inner surface in one form in which the outer casing 10 is divided into two parts. In the example shown in the drawing, one gas release pipe 6 which is duplicated and a bottom through hole is formed. The ceiling pipe 13 formed by molding a part of the other ceiling part is incorporated in this part.

Next, the connection between the two batteries 2 and 3 and the spacer 12 in the third embodiment will be described with reference to FIGS. FIG. 5 is a perspective view showing the positions of the three connecting cords that connect the spacer 12 and the batteries 2 and 3 shown in FIG. FIG. 6 is a plan view of the upper surface of the spacer 12 seen from the ceiling of the outer casing 10 with FIG. 5 incorporated into FIG. In addition, FIG. 7 shows a four-sided view of the top surface, back surface, front surface, and side surface of the separator 12.

As shown in FIG. 5, the three connecting cords connect an anode terminal plate connecting cord 21 for connecting the anode of the battery 2 to the anode terminal plate 4 and a cathode of the battery 3 to the cathode terminal plate 5. There is a cathode terminal plate connection cord 22 and an inter-battery connection cord 23 that connects the cathode of the battery 2 and the anode of the battery 3. As shown in FIG. 7, the spacer 12 has appropriate vent holes for the two pipes from the upper surface and the back surface due to the gas vent hole 6, and two batteries 2, 3 on both sides with the gas vent hole 6 interposed therebetween.
Storage space 31 for batteries, inter-battery connection cord 23
It has an inter-battery connecting cord hole 32 for passing the battery and an anode terminal plate connecting cord hole 33 for passing the anode terminal plate connecting cord 21.

As described above, when an overcurrent flows through a single battery due to a short circuit or the like, the temperature rises and the internal pressure of the battery rises. As a result, in the battery, the safety valve on the anode surface opens, and the electrolytic solution and the gas containing the electrolytic solution are ejected. Due to this ejection, the internal pressure of the battery pack rises, so that the waterproof seal at the bottom of the outer casing is peeled off, and the ejected gas is released. The ejected electrolytic solution is absorbed by the hygroscopic material inside the bottom part from the safety valve facing the bottom part.

When the hygroscopic material fully absorbs the electrolytic solution, or when the ejection speed is too high to compensate for the absorbing rate of the hygroscopic material, the electrolytic solution first collects at the bottom and then along the degassing pipe. Ascend inside the ceiling pipe,
It is absorbed by the ceiling moisture absorbent in the ceiling portion of the ceiling pipe. Since it takes time for the electrolytic solution to reach the degassing hole in the degassing pipe, the electrolytic solution is usually absorbed by the two hygroscopic materials. Therefore, the electrolytic solution is prevented from flowing out of the battery pack.

In the above description, the number of batteries contained in the battery pack is two, but the number is not limited. Further, both the gas vent pipe shown in FIG. 1 and the ceiling pipe shown in FIG. 3 have been described as being molded as part of the outer casing, but a single pipe is fitted in the outer casing. Good. As described above, although the structure is illustrated and described in the above description, the shape and the configuration are arbitrary as long as the above functions are satisfied, and the above description does not limit the present invention.

[0027]

As described above, according to the present invention, a gas vent pipe having an opening at the bottom of the outer casing and a gas vent hole closed by a waterproof seal has a height from the bottom inside the outer casing. Since it is a through hole of the built-in battery, by placing the safety valve of the built-in battery on the bottom side, in order for the electrolyte ejected from the safety valve of the battery to flow out of the outer casing due to a short circuit accident of the battery, etc. The amount and time required for the ejected electrolytic solution to reach the height of the degassing pipe are required, which makes it difficult for the electrolytic solution to flow out of the outer casing.

By providing a hygroscopic material near the battery safety valve at the bottom of the outer casing, and by further providing a ceiling absorbent by covering the ceiling vent of the degassing pipe with a ceiling pipe. , The bottom of the outer casing absorbs the electrolyte sufficiently, and even if the electrolyte reaches the height of the degassing pipe, the electrolyte can be absorbed by the absorbent material on the ceiling. Preventing it from leaking out of the cabinet,
It is possible to ensure safety.

[Brief description of drawings]

FIG. 1 is an explanatory view of an inner structure showing a first embodiment of the present invention in a sectional form.

FIG. 2 is an explanatory diagram of an inner structure showing a second embodiment of the present invention in a sectional form.

FIG. 3 is an explanatory view of the inner structure showing the third embodiment of the present invention in sectional form.

FIG. 4 is a perspective view illustrating the arrangement of inner components with the separator removed from FIG.

5 is a perspective view showing positions of three connection cords connecting the spacer and the battery shown in FIG. 3. FIG.

FIG. 6 is a plan view of the upper surface of the spacer seen from the ceiling of the outer casing in the state where FIG. 5 is incorporated in FIG.

FIG. 7 is a four-sided view showing a top surface, a back surface, a front surface, and a side surface of a separator.

FIG. 8 is an explanatory view of an inner structure showing a conventional example.

[Explanation of symbols]

1, 10 outer casing A few batteries 4 Anode terminal plate 5 Cathode terminal plate 6 vent holes 7, 11 Degassing pipe 8 waterproof seal 9 Hygroscopic material 12 separators 13 ceiling pipe 14 Ceiling moisture absorbent 15 Separator joint

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliography Sho 61-123468 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 2/10

Claims (5)

(57) [Claims] 1. A battery pack having an explosion-proof structure, wherein an outer casing has a gas vent hole and a waterproof seal at a bottom portion, and an anode terminal plate and a cathode terminal plate at a ceiling portion, and at least one battery is housed inside. Is a burst-proof
All valves are placed inside the outer casing, facing the bottom,
The amount of electrolyte leaked from the safety valve is collected in the bottom of the outer casing.
Full height and the battery pack, characterized in that it comprises a venting pipe said none from the bottom a cylindrical shape extending in the ceiling direction and the through-hole of greater outer casing from the position of the safety valve and the vent holes. 2. The battery pack according to claim 1, further comprising a hygroscopic material near the safety valve of the battery on the inner bottom of the outer casing. 3. The degassing ceiling pipe according to claim 1, wherein the degassing ceiling pipe has a shape extending from the ceiling portion to a bottom direction inside the outer casing, and the degassing pipe is positioned inside with a gap. Characteristic battery pack. 4. The battery pack according to claim 3, comprising a hygroscopic material attached to a ceiling portion of the ceiling pipe as a ceiling hygroscopic material. 5. The battery pack according to claim 1, wherein the outer casing includes a separator for arranging internal constituent elements at predetermined positions.