JP2012243519A - Secondary battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent harmful gas from being exhausted to an external environment from a secondary battery by improving gas absorption efficiency.SOLUTION: A secondary battery system comprises: one or a plurality of batteries in each of which a safety valve is provided; and a gas absorption device including a gas introduction part, a gas exhaust part provided at a site different from that of the gas introduction part, and an absorber for absorbing gas. The internal pressure of the gas absorption device is reduced as compared with the pressure inside the batteries. Inert gas may be sealed inside the gas absorption device. By the constitution, gas generated inside the batteries is easy to inflow inside the gas adsorption device, so that the absorption efficiency of the gas absorber can be improved.

Description

  The present invention relates to a secondary battery system having a function of preventing ejection of gas generated inside during an abnormality.

  In the secondary battery, the internal temperature rises when an abnormality such as overcharge or short circuit occurs, a large amount of gas is generated, and the pressure rises. Therefore, the secondary battery container is provided with a safety valve, and when a predetermined pressure is exceeded, the gas generated from the electrolyte is safely discharged through the safety valve. On the other hand, since the gas emitted from the inside of the battery contains a large amount of flammable substances and toxic substances to the human body, a mechanism is required to prevent the gas from being discharged into the external environment as it is.

  Patent Document 1 discloses a system in which flammable gas released from a gas discharge valve of a secondary battery is introduced into a storage container capable of changing its volume, thereby isolating it from oxygen in the atmosphere and preventing ignition of the flammable gas. Is disclosed. Patent Document 2 relates to an electric double layer capacitor, but discloses several technical means for releasing the gas generated in the container (of the electric double layer capacitor) to the outside. In addition, a gas absorption device in which a gas absorption material having a large number of pores is enclosed is known (Patent Document 3).

JP 2000-12082 A JP 2006-261196 A Japanese Utility Model Publication No. 5-34660

  The safety valve of the secondary battery and the valve provided in the gas introduction part of the gas absorption device are connected in a state of maintaining airtightness. The gas absorption device has a pressure release valve in the gas discharge section for safety, but is closed when the pressure is lower than the operating valve pressure. Therefore, a predetermined amount of the gas generated inside the secondary battery and introduced into the gas absorption device is trapped in a large number of pores of the gas absorption material by contacting the gas absorption material up to a certain amount. Is done. The gas absorbing material is filled with a necessary amount capable of absorbing an assumed gas generation amount based on the type and capacity of the secondary battery.

  However, gas movement occurs due to the pressure difference between the inside of the secondary battery and the inside of the gas absorption device. Therefore, if the pressure release valve is closed, the gas moving speed decreases as the pressure difference decreases, and the gas moves into the sealed space. It becomes easy to stay in. As a result, even if the absorption capacity of the gas absorbent material has not reached saturation, the opportunity for contact with the gas absorbent material is lost, and the gas absorption efficiency rapidly decreases.

  Even in that case, as the amount of gas generated from the secondary battery continues, the internal pressure of the gas absorption device increases with the passage of time, and when the predetermined operating valve pressure is reached, the pressure release valve of the gas absorption device opens, resulting in retention. The gas is dissolved and some gas is absorbed. However, harmful gases such as flammable gas and toxic gas that cannot be absorbed by the gas absorption device may be discharged from the pressure release valve at the same time.

  The present invention has been made in view of the above, and an object of the present invention is to prevent harmful gases from being discharged to the external environment regardless of the amount of gas generated.

  A secondary battery system according to the present invention includes one or a plurality of batteries provided with a safety valve and a gas absorption device, and the gas absorption device is different from the gas introduction portion. The gas absorption device is provided with a gas discharge part and a gas absorption material, and the internal pressure of the gas absorption device is set lower than the internal pressure of the battery (negative pressure).

  According to this configuration, when the gas is generated when the secondary battery is abnormal, the gas discharged from the safety valve is sucked into the gas absorption device side through the gas introduction unit, so that the gas introduction efficiency at the initial stage of gas generation is improved. The In addition, by keeping the inside of the gas absorption device under reduced pressure, the air contained in the pores of the gas absorption material is reduced, and the gas absorption efficiency is reduced due to oxidation of the gas absorption material and oxidation of gas discharged from the safety valve. It can be suppressed. Therefore, when the amount of generated gas is small, all the gas discharged from the safety valve of the secondary battery can be kept in the gas absorption device with the pressure release valve of the gas discharge section closed. When the internal pressure of the gas absorption device increases and the pressure release valve opens, the gas absorption device removes flammable gas or toxic gas and discharges safe gas from the pressure release valve.

  The gas absorber is preferably filled with an inert gas or a gas not containing oxygen. If the pressure inside the gas absorber is reduced too much, the pressure valve of the secondary battery and the valve on the gas absorption device side are easily operated by the differential pressure, so it is preferable that a small amount of gas is enclosed rather than high vacuum. It is. The reason why the inert gas is preferable is that oxygen is not included. Accordingly, the gas is not limited to an inert gas as long as it is a gas from which oxygen is removed. One of the reasons why a gas that does not contain oxygen is preferable is that the gas discharged from the safety valve is easy to react with oxygen, and if the gas reacts with the oxygen in the gas absorption device and changes its quality, the absorption that the gas absorbent material originally planned is The target gas is different, and the gas absorption efficiency is reduced.

  The gas absorption device may include a gas recovery bag in the gas discharge unit. When the gas recovery bag is provided, harmful gas can be isolated from the external environment even when the pressure release valve of the gas absorption device is opened.

  The secondary battery system according to the present invention can be applied to a battery module including a plurality of batteries. That is, a plurality of batteries may be provided, and the safety valve of each battery may be connected to one integrated pipe.

  The gas absorbent of the secondary battery system according to the present invention preferably contains activated carbon or a molecular compound.

  According to the present invention, by setting the pressure inside the gas absorption device to be lower than the pressure inside the battery, the gas generated inside the battery can easily flow into the gas absorption device, and the gas absorption material Absorption efficiency can be improved. If a gas recovery bag is connected to the pressure relief valve of the gas absorber, harmful gases can be isolated from the external environment.

Secondary battery system of the first embodiment Internal structure of cartridge of secondary battery system of first embodiment Cartridge of the second embodiment Cartridge of the second embodiment Configuration example of attaching means of gas recovery bag attached to cartridge of second embodiment, (a) fitting type, (b) screwing type Other structural examples of attachment means of the gas recovery bag attached to the cartridge of the second embodiment, (c) slide type, (d) adhesive type Secondary battery system of the third embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the component which exhibits the same or the same kind of function, description may be abbreviate | omitted using the same code | symbol. Each embodiment is only an example and does not give a limited interpretation on the present invention.
(First embodiment)
FIG. 1 shows the configuration of the secondary battery system of the first embodiment. The arrows indicate the flow direction of gas discharged from the inside of the secondary battery 11. As shown in FIG. 1, the secondary battery system 21 includes a secondary battery 11 and a cartridge 12 as a gas absorption device.

  The cartridge 12 has a first cartridge valve 12b as a gas introduction part at the bottom of the cartridge container 12a and a second cartridge valve 12c as a gas discharge part at the top. Each of these valves is a pressure valve that opens at a predetermined pressure.

  In order to make gas stay in the cartridge for a long time, it is preferable that the opening pressure (operating valve pressure) of the second cartridge valve 12c is higher than that of the first cartridge valve as the gas introducing portion.

  FIG. 2 is a cross-sectional view for explaining the internal structure of the cartridge 12. A gas absorbing material 13 is provided inside the cartridge container 12a. The safety valve 4 of the secondary battery 11 and the first cartridge valve 12b are connected by attachment members 3a and 12e (FIG. 1) in a state where airtightness is maintained so that liquid or gas does not leak outside.

  The gas discharged from the safety valve 4 flows into the cartridge 12 from the first cartridge valve 12b, passes through the gas absorbing material 13, and after the predetermined gas component is removed, the second gas when the operating valve pressure is exceeded. Out of the cartridge valve 12c.

  The internal pressure of the cartridge container 12a is set lower than the internal pressure of the secondary battery 11, that is, a negative pressure. By doing so, gas easily flows into the cartridge. However, if the pressure is too low, the safety valve 4 of the secondary battery 11 and the first cartridge valve 12a share the first cartridge valve 12a. The operating valve pressure of the cartridge valve is preferably set in advance higher than the operating pressure of the safety valve 4 of the secondary battery 11 (usually about 5 to 10 atm) in consideration of the reduced pressure of the cartridge.

An inert gas 26 such as nitrogen (N ₂ ), argon (Ar), or helium (He) is preferably sealed in the cartridge. The gas absorbent 13 is generally made of a material having a large number of fine pores and a large specific surface area, such as activated carbon, a molecular compound containing an organic material, or an inorganic porous material. Some of these materials are easily oxidized by oxygen in the air, and they may change in quality and cause a decrease in absorption efficiency. Therefore, by enclosing an inert gas or a non-oxidizing gas in the cartridge, the gas absorbent 13 is less likely to be oxidized by oxygen in the air. As a result, alteration of the gas absorbent is suppressed, and absorption efficiency is improved.

  As a specific example of the gas absorbing material 13, it is preferable to use a molecular compound including an organic material or an inorganic porous material, and a plurality of materials may be mixed and used. This is because the electrolyte solution and various gases can be efficiently absorbed by the combination of a plurality of molecular compounds.

  A molecular compound is a kind of addition compound that can be formed by the penetration of another compound into the gaps formed in the three-dimensional network structure of a single compound crystal. Two or more types of compounds that can exist stably alone Is a compound bonded by a relatively weak interaction other than a covalent bond, such as a hydrogen bond or van der Waals force. Specifically, hydrates, solvates, addition compounds, inclusion compounds and the like are included. Such a molecular compound can be formed by a contact reaction between a compound that forms the molecular compound and an electrolytic solution, and the electrolytic solution can be immobilized in the molecular compound.

  Examples of the material forming the molecular compound include an inclusion compound formed by inclusion of an electrolytic solution with a host compound by a contact reaction between the compound and the electrolytic solution. Among the materials forming the molecular compound, as the host compound that forms the clathrate compound that clathrates the electrolyte, those composed of organic compounds, inorganic compounds, and organic / inorganic composite compounds are known. Monomolecular, multimolecular, and polymeric hosts are known.

The molecular compound preferably has an average particle diameter of 10 to 5000 [μm], particularly 200 to 300 [μm], considering the contact efficiency with gas and the filling efficiency when filled in a container, etc., and its specific surface area It is preferably 30 [m ² / g] or more, particularly 200 [m ² / g] or more.

  Examples of molecular compounds that can be used for the gas absorbent 13 include cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, calixarenes, urea, deoxycholic acid, cholic acid, 1 Acetylene alcohols such as 1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol, bisphenols such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1,2 , 2-tetrakis (4-hydroxyphenyl) ethane and other tetrakisphenols, bis-β-naphthol and other naphthols, diphenic acid bis (dicyclohexylamide) and other carboxylic acid amides, 2,5-di-t-butyl Hydroquinones such as hydroquinone, chitin, chitosan, porous silica, metal polar Structure, calcium silicate, magnesium silicate, magnesium aluminate metasilicate, activated alumina, apatite, porous glass, magnesium silicate, aluminum silicate, porous organometallic compound, carbon black, nanocarbon, zeolite, titanium oxide Magnesium oxide and the like are preferable. However, it is preferable to select the gas absorbent 13 according to the gas or the electrolyte that is mainly the object of absorption.

(Second Embodiment)
3 and 4 show the cartridge of the second embodiment. The cartridge 52 has a first cartridge valve 52b at the bottom of the cartridge container 52a, a second cartridge valve 52c at the top, and the gas absorbent 13 inside the cartridge container 52a. The first cartridge valve 52b is connected to a safety valve of the secondary battery by a mounting member (not shown) in a state where airtightness is maintained so that liquid or gas does not leak outside.

  In the present embodiment, the gas recovery bag 27 is attached to the outside of the second cartridge valve 52c that is the gas discharge part side of the cartridge. FIG. 3 shows a state in which the gas recovery bag is folded, and FIG. 4 shows a state in which gas flows into the gas recovery bag and the bag is opened.

  The gas discharged from the safety valve of the secondary battery flows into the cartridge 52 from the first cartridge valve 52b, passes through the gas absorbing material 13, and after the predetermined gas is removed, the second cartridge valve 52c. The gas is recovered from the gas recovery bag 27 as shown in FIG.

  The material and structure of the gas recovery bag 27 are not particularly limited, but are preferably selected in consideration of the resistance, heat resistance, pressure resistance, and the like of the gas to be recovered and the electrolyte. Specifically, as the material of the gas recovery bag 27, it is preferable to use PET resin, PVF (vinyl fluoride) resin, nylon or the like. The structure of the gas recovery bag 27 is preferably a container capable of changing volume. Specifically, a balloon type, a bellows type, etc. are mentioned. The connection between the gas introduction part of the gas recovery bag 27 and the second cartridge valve 52c provided in the gas discharge part of the gas absorption device is a fitting type, a screwing type, a sliding type, an adhesive type (welding with an adhesive or a solvent) The attachment means which can maintain airtightness such as is preferable. The gas recovery bag 27 may be provided with a valve in order to prevent bursting. In addition, an O-ring can be used at the connection location in order to maintain airtightness. The O-ring is preferably selected in consideration of the resistance to the gas to be recovered and the electrolyte, heat resistance, pressure resistance, and the like. Examples of the material of the O-ring include NBR (nitrile), SBR (styrene butadiene), Viton, and silicon.

  5 (a) to 5 (b) and FIGS. 6 (c) to 6 (d) are examples of the configuration of the attaching means of the gas recovery bag 27 attached to the cartridge container 52a of the second embodiment. Show.

  FIG. 5A is a fitting type example, and has a through hole 60 that communicates inside and outside on the outside of the second cartridge valve 52c that is a gas discharge part of the cartridge container 52a. A locking recess 61 is provided inside the through-hole 60 as shown in the figure. On the other hand, a locking projection 71 fitted into the locking recess 61 is fitted at the tip of the gas introduction portion 70 of the gas recovery bag 27. Is provided. Further, an O-ring 65 is provided around the through hole 60 in order to improve airtightness.

  FIG. 5B is an example of a screwing type, and a screw groove 62 is provided inside the through hole 60 as shown in the figure, and on the other hand, on the outer peripheral portion of the gas introduction part 70 of the gas recovery bag 27. A thread 72 that is screwed into the thread groove 62 is provided.

  FIG. 6C is an example of a slide type, in which a first locking member 63 is provided outside the O-ring 65 as shown in the figure, and on the other hand, at the tip of the gas introduction part 70 of the gas recovery bag. A second locking member 73 is provided that fits while sliding on the first locking member 63.

  FIG. 6D is an example of an adhesive type, and a through hole 60 and a gas introduction part 70 fitted to the through hole 60 are fixed with an adhesive 80. Instead of the adhesive, a known joining means such as welding may be substituted.

  According to the attaching means as described above, the gas recovery bag can be easily attached and detached.

  By applying the cartridge shown in this embodiment to the gas absorption device of the first embodiment, an effect of reliably preventing harmful gases such as flammable gas and carbon monoxide from being discharged to the external environment is expected. Is done.

(Third embodiment)
The secondary battery system shown in the first and second embodiments may be applied to a battery module in which a plurality of secondary batteries are used side by side.

  FIG. 7 shows the configuration of the secondary battery system of the third embodiment. The individual secondary batteries are the same as those shown in FIG. As shown in FIG. 7, the secondary battery system 31 includes a battery module 23 in which a plurality of secondary batteries 11 are juxtaposed, at least one gas absorption device 32, and at least one integrated pipe 24. As in the cartridge 12 shown in FIG. 2, the internal pressure of the gas absorber is set lower than the internal pressure of each secondary battery. The gas absorption device 32 can be installed at an arbitrary place by a centralized pipe.

  The integrated pipe 24 has the same number of distribution parts 24a as the number of safety valves of the secondary battery 11, and a main body part 24b that integrates the plurality of distribution parts into one. One end 24 of the integrated pipe 24 is connected to the safety valve 4 of each secondary battery 11, and the other end is connected to the gas absorption device 32.

  In the secondary battery system according to the third embodiment, the gas discharged from the plurality of secondary batteries can be collected by the centralized piping 24 and absorbed by the gas absorption device 32. According to such a configuration, there is an advantage that the high-temperature electrolyte is cooled when passing through the concentrated pipe, and the volume of the gas is reduced. Therefore, according to the third embodiment, the absorption efficiency is further improved.

4 Safety valve 11 Secondary battery 12, 52 Cartridge 12a, 52a Cartridge container 12b, 52b First cartridge valve 12c, 52c Second cartridge valve 13 Absorbent material 21, 31 Secondary battery system 23 Battery module 24 Integrated piping 26 Inactive Gas 27 Gas recovery bag 32 Gas absorption device 60 Through hole 61 Locking recess 62 Screw groove 63 First locking member 65 O-ring 70 Gas introduction portion 71 Locking protrusion 72 Screw thread 73 Second locking member 80 Adhesion Agent

Claims (5)

  One or a plurality of batteries provided with a safety valve and a gas absorption device, the gas absorption device comprising a gas introduction part, a gas discharge part provided in a part different from the gas introduction part, and a gas absorption A secondary battery system, wherein the gas absorption device is set to have an internal pressure lower than the internal pressure of the battery.   The secondary battery system according to claim 1, wherein an inert gas is sealed inside the gas absorption device.   The secondary battery system according to claim 1, wherein the gas absorption device includes a gas recovery bag in the gas discharge unit.   The secondary battery system according to any one of claims 1 to 3, further comprising a plurality of batteries, wherein a safety valve of each battery is connected to one integrated pipe.   The secondary battery system according to claim 1, wherein the absorbent material includes activated carbon or a molecular compound.

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