JP2010287489A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of quickly cooling the battery even if thermal runaway is generated on the inside of a laminate, lowering the temperature of gas ejecting to the outside, and suppressing the amount of ejecting gas. <P>SOLUTION: The secondary battery 10 includes: a container 11 storing an electrolyte on the inside; a laminate 12 including a sheet-like positive electrode plate 18 and a sheet-like negative electrode plate 20, which are alternately laminated, and a separator 20 interposed between the positive electrode plate 18 and the negative electrode plate 20, and housed in the container 11; and a fire extinguisher-housing structure 22 arranged between the positive electrode plate 18 or the negative electrode plate 20 of the laminate 12 and the container, housing a fire extinguisher on the inside, and being broken at the prescribed temperature. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a secondary battery.

  In recent years, secondary batteries that can be repeatedly charged and discharged have been widely used in various fields. For example, a small type is used as a power source for an electronic device such as a mobile phone or a video camera, and a large type is used as a power source for an electric vehicle or a household power storage device. As such a secondary battery, a non-aqueous electrolyte secondary battery such as a stacked lithium ion secondary battery has been developed (see, for example, Patent Documents 1 and 2).

  In such a secondary battery, at least one of the positive electrode plate and the negative electrode plate is packaged with a separator, and the positive electrode plate and the negative electrode plate are alternately laminated to form a laminate. And the heat | fever which generate | occur | produces in the positive electrode plate in a container, a negative electrode plate, etc. in the case of charging / discharging etc. is radiated from the container outer wall and terminal part which accommodate a positive electrode plate and a negative electrode plate.

  On the other hand, when a short circuit occurs inside the lithium ion secondary battery, a large current flows and heat is generated, and the temperature of the battery suddenly rises, so-called thermal runaway may occur. At this time, since the electrolytic solution contains a flammable organic solvent, the electrolytic solution may be vaporized to increase the internal pressure and the container may burst or the electrolytic solution may ignite. In order to suppress such bursting / ignition, a material in which an endothermic substance is added to a positive electrode plate or a negative electrode plate (for example, see Patent Document 3) has been proposed.

JP 2003-45498 A JP 2007-273348 A JP-A-11-154535

  However, in the case of the above-described conventional secondary battery, the heat generated in the internal positive electrode plate, negative electrode plate, and the like is radiated from the outer wall and terminal portion of the container that accommodates the positive electrode plate and negative electrode plate during charging and discharging. For this reason, the heat in the center of the battery that does not directly contact the outer wall of the container cannot be sufficiently dissipated to the outside, and the rise in battery temperature that causes rupture and ignition cannot be effectively suppressed. In addition, there is a problem that even if an endothermic substance is added, the amount of addition is limited, and when thermal runaway occurs, bursting / ignition cannot be suppressed quickly.

  The present invention has been made in view of the above circumstances, and can be quickly cooled even if thermal runaway occurs in the laminated body, reducing the temperature of the gas ejected to the outside and suppressing the gas amount. An object is to provide a rechargeable battery.

The present invention employs the following means in order to solve the above problems.
A secondary battery according to the present invention includes a container for storing an electrolyte therein, sheet-like positive and negative plates stacked alternately, and a separator disposed between the positive and negative plates. And disposed between the positive electrode plate and the negative electrode plate of the laminate, containing a fire extinguisher inside, and destroyed at a predetermined temperature. And a fire extinguisher containing structure.

  In the present invention, the extinguishing agent is interposed between any of the positive electrode plate and the negative electrode plate. Therefore, even when heat generation or thermal runaway occurs due to an internal short circuit or the like inside the laminate, the extinguishing agent containing structure at a predetermined temperature By destroying, fire extinguishing agent can be released and fire can be extinguished quickly.

Moreover, the secondary battery according to the present invention is the secondary battery, wherein the fire extinguishing agent-containing structure is disposed in a central portion in the stacking direction of the stacked body.
The present invention can be suitably extinguished even if heat generation and thermal runaway occur in the central portion of the laminate that tends to accumulate heat.

  Moreover, the secondary battery according to the present invention is the secondary battery, wherein the fire extinguisher containing structure is configured to be destroyed at a temperature of 100 to 300 ° C. to release the fire extinguisher. It is characterized by.

According to the present invention, the fire extinguishing agent housing structure is destroyed immediately after the temperature rise, so that the thermal runaway can be suppressed from the initial stage of the thermal runaway by the fire extinguishing agent released from the fire extinguishing agent housing structure.

  According to the present invention, even if thermal runaway occurs inside the laminate, it can be quickly cooled, and the temperature of the gas ejected to the outside can be lowered and the amount of gas can be suppressed.

1 is a partially broken perspective view showing a secondary battery according to an embodiment of the present invention. It is the II-II cross-sectional schematic diagram of FIG. It is a partial cross section figure which shows the fire extinguisher accommodation structure of the secondary battery which concerns on one Embodiment of this invention. It is a perspective view which shows the other example of the secondary battery which concerns on one Embodiment of this invention.

An embodiment according to the present invention will be described with reference to FIGS.
The secondary battery 10 according to the present embodiment includes a container 11 that stores an electrolytic solution made of an organic material therein, a laminated body 12 disposed in the container 11, and a fire extinguishing agent 13 disposed in the laminated body 12. It is equipped with.

  The container 11 is made of, for example, aluminum, and a positive electrode terminal 15, a negative electrode terminal 16, and an aluminum safety valve 17 are arranged on the upper part. The stacked body 12 includes a plurality of positive plates 18 and negative plates 20 that are alternately stacked in the stacking direction X so as to be immersed in the electrolytic solution, and a plurality of layers disposed between the positive plates 18 and the negative plates 20. And a separator 21. In FIG. 1 and FIG. 2, the positive electrode plate 18, the negative electrode plate 20, and the separator 21 are displayed as having a sufficient thickness for easy viewing of the drawings, but all are configured in a sheet form. .

  Tabs 18 </ b> A and 20 </ b> A are arranged on the respective edges of the positive electrode plate 18 and the negative electrode plate 20 on the positive electrode terminal 15 and negative electrode terminal 16 side. Here, in the positive electrode plate 18 and the negative electrode plate 20, the tabs 18 </ b> A and 20 </ b> A are arranged so as to be biased to either side from the edge center. And the positive electrode plate 18 and the negative electrode plate 20 are laminated | stacked so that mutual tab 18A, 20A may not be biased | biased from the edge center to a different side. The tab 18A of the positive electrode plate 18 is connected to the positive electrode terminal 15, and the tab 20A of the negative electrode plate 20 is connected to the negative electrode terminal 16.

  The separator 21 is for insulating the positive electrode plate 18 and the negative electrode plate 20 adjacent to each other, and is made of a sheet-like resin such as polypropylene, for example. In addition, at least one of the positive electrode plate 18 and the negative electrode plate 20 is sealed to the separator 21 with the tab 18A or the tab 20A protruding, so that the adjacent positive electrode plate 18 and negative electrode plate 20 are insulated. May be.

  The extinguishing agent 13 is accommodated in the extinguishing agent accommodating structure 22. The fire extinguishing agent 13 may be any material that has a function of suppressing the thermal runaway reaction of the battery by endotherm or reaction material coating, and that can block air without increasing the temperature even when the heat is absorbed. . For example, as the fire extinguishing agent 13, a mixture of two or more kinds including at least one material among an endothermic substance, an alkali, an acid, a carbon compound, a carbonic acid compound, a nitrogen compound, water, and a surfactant can be used. Here, the endothermic substance is a substance that causes an endothermic reaction when ripened. The endothermic substance causes an endothermic reaction to absorb heat when the temperature of the secondary battery 10 is about to rise, and effectively suppresses thermal runaway.

  More specifically, a K-type BC fire extinguisher containing potassium bicarbonate as a main component, a Na-type BC fire extinguisher containing sodium bicarbonate as a main component, and a KU type containing a reaction product of potassium bicarbonate and urea as a main component. A BC fire extinguisher and an ABC fire extinguisher based on ammonium dihydrogen phosphate can be used.

In addition, the following chemicals can be used as fire extinguishing agents filled in the fire extinguishing agent housing structure 22:
(1) Alkaline absorptive substance Potassium bicarbonate, potassium carbonate, ammonium bicarbonate, ammonium carbonate, potassium allophanate, sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate (2) Acid endothermic substance Ammonium dihydrogen phosphate, Ammonium hydrogen phosphate, ammonium phosphate, ammonium sulfate (3) Mixture of water and surfactant Alkyl sulfate ester aqueous solution, perfluorooctanoate aqueous solution (4) Ethylene glycol (5) Hydrated metal compound Aluminum hydroxide hydrate , Magnesium hydroxide hydrate, Magnesium carbonate hydrate, Antimony oxide hydrate (6) Boron compound Boric acid, Zinc borate (7) Phosphorus compound Triphenyl phosphate, bisphenol A, tricresyl phosphate, Trixy Niruhosufeto, ammonium polyphosphate (8) a halogen compound chlorinated paraffin and decabromodiphenyl ether, water, and suppress an increase in the temperature of the secondary battery 10, effectively suppressing the thermal runaway. Furthermore, the surfactant coats the contents of the secondary battery 10 and its reactants, and effectively prevents the secondary battery 10 from firing.

  The extinguishing agent 13 may be in any form as long as it can be accommodated in the extinguishing agent housing structure 22, and any solid or liquid extinguishing agent can be used. However, since the liquid material has high fluidity, the fire extinguisher 13 easily leaks out of the fire extinguisher containing structure 22 when a slight defect occurs in the fire extinguisher containing structure 22, which adversely affects the battery performance. There is a possibility of effect. Therefore, it is preferable that a solid material is used as the extinguishing agent 13 accommodated in the extinguishing agent accommodating structure 22. As a solid, a powder or gel is easy to handle, and may be accommodated in the fire extinguisher containing structure 22 in a powder or gel form, and extinguish as a compression molded body obtained by compressing and molding powder. It may be accommodated in the agent accommodating structure 22. The extinguishing agent 13 being accommodated in the extinguishing agent housing structure 22 after being compressed and molded is effective for increasing the filling amount of the extinguishing agent and improving the thermal runaway suppressing action of the extinguishing agent housing structure 22. It is.

  The fire extinguishing agent containment structure 22 is configured to tear at an appropriate temperature. If the fire extinguisher containing structure 22 is configured to be broken at too low temperature, the fire extinguisher containing structure 22 is broken and the fire extinguisher 13 is released even when the secondary battery 10 is operating normally. This hinders the operation of the secondary battery 10. On the other hand, if the temperature at which the extinguishing agent housing structure 22 is broken is too high, the effect of suppressing the bursting / ignition of the secondary battery 10 by the extinguishing agent is weakened. The fire extinguisher containing structure 22 is preferably configured to be broken at a temperature of 100 to 300 ° C.

  As shown in FIG. 3A, the extinguishing agent housing structure 22 is configured to laminate the extinguishing agent 13 and be destroyed at a temperature of 100 to 300 ° C. to release the extinguishing agent 13 to the outside. Yes. The fire extinguishing agent housing structure 22 is formed with substantially the same size and thickness as the positive electrode plate 18 and the negative electrode plate 20.

  A more preferable structure of the fire extinguishing agent housing structure 22 is specifically shown in FIG. The fire extinguishing agent housing structure 22 shown in FIG. 3B is composed of a PP (polypropylene) film 22A, an aluminum film 22B, a PP film 22C, and an exterior film 22D. The exterior film 22D is made of, for example, nylon or PET (polyethylene terephthalate). Of the four films of the fire extinguisher containing structure 22, the PP film 22C is located on the fire extinguisher 13 side, and the exterior film 22D is located on the electrolyte side. As the PP film 22C is fused, the fire extinguisher containing structure 22 is formed in a bag shape. The extinguishing agent housing structure 22 shown in FIG. 3B includes the three-layer structure of the PP film 22C, the aluminum film 22B, and the PP films 22A and 22C, so that the temperature at which the extinguishing agent housing structure 22 is broken is appropriate. Furthermore, the piercing strength of the fire extinguishing agent housing structure 22 is appropriately adjusted. The exterior film 22D is used to facilitate release when the PP film 22A is fused.

  Another suitable structure of the extinguishing agent housing structure 22 is shown in FIG. The extinguishing agent housing structure 22 shown in FIG. 3C is composed of a PP (polypropylene) film 22A, an aluminum film 22B, a nylon film 22E, and a PET film 22F. The PP film 22A is located on the fire extinguishing agent 13 side, and the PET film 22F is located on the electrolyte side. However, the PET film 22F is not necessarily required, and the nylon film 22E may face the electrolytic solution. Even in this structure, the temperature at which the extinguishing agent accommodating structure 22 is broken is appropriately adjusted, and the piercing strength of the extinguishing agent accommodating structure 22 is appropriately adjusted.

  According to the secondary battery 10, the fire extinguisher containing structure 22 that contains the fire extinguisher 13 is interposed between either the positive electrode plate 18 or the negative electrode plate 20 in the laminate 12. Therefore, when heat generation / thermal runaway occurs due to an internal short circuit or the like inside the laminate 12, the fire extinguisher containing structure 22 is destroyed at a temperature of 100 to 300 ° C., so that the fire extinguisher 13 can be discharged to the outside. Rapid fire extinguishing before the temperature reaches 500 ° C. can be performed more effectively. Therefore, even if thermal runaway occurs in the laminate 12, it can be quickly cooled, and the temperature of the gas ejected to the outside can be lowered and the amount of gas can be suppressed.

  In particular, when the fire extinguisher containing structure 22 is disposed at the center of the stack 12 in the stacking direction X, the fire can be effectively extinguished even at the center of the battery that tends to be high in temperature, and the generated heat is also suitable. The heat can be radiated to the outside of the container 11.

  Moreover, since the fire extinguisher containing structure 22 is destroyed at a temperature of 100 to 300 ° C., the fire extinguisher containing structure 22 is destroyed immediately after the temperature rise, and the fire extinguisher 13 discharged from the fire extinguisher containing structure 22 is used. Can suppress thermal runaway from the initial stage of thermal runaway.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the fire extinguishing agent housing structure 22 is interposed between any one of the positive electrode plate 18 and the negative electrode plate 20 that is the central portion in the stacking direction X of the stacked body 12, and the edge portion is in heat transfer with the container 11. It may be fixed to a sheet-like heat sink that is in contact with the plate.

  As shown in FIG. 4, the heat radiating plate may be a heat radiating plate 26 including a sheet-shaped heat radiating plate main body 23 and a contact portion 25. The heat sink main body 23 is disposed between the positive electrode 18 and the negative electrode 20 of the laminate 12. The contact portion 25 contacts the heat sink main body 23 with the inner surface of the container 11 at the contact surface 25A. In this case, the fire extinguishing agent housing structure 22 is fixed to both surfaces of the heat sink main body 23.

  In the portion where the heat sink main body 23 is interposed, separators 21 are arranged on both sides of the heat sink main body 23 in order to insulate between the heat sink main body 23 and each of the positive electrode plate 18 and the negative electrode plate 20. The contact portion 25 has a contact surface 25A along the inner surface of the container 11, on the side surface and bottom surface side other than the upper side of the container 11, and the contact surface 25A and the radiator plate main body 23 have a substantially T-shaped cross section. In other words, the contact surface 25 </ b> A is disposed so as to be orthogonal to the surface disposed on the heat sink main body 23. And it arrange | positions in the container 11 so that the inner surface of the container 11 may be pressed with the contact surface 25A.

Here, the heat sink main body 23 and the contact portion 25 may be integrally formed, and may be formed by, for example, extrusion molding or connecting each other by welding or the like.
Moreover, the contact part 25 should just be provided in the at least any surface of the both sides | surfaces and bottom face of the container 11, and can thermally radiate | emit effectively through the said contact surface 25A. Here, the contact portion 25 may be provided on a part of the surface, and a gap may be formed between the radiator plate main body 23 and the inner surface of the container 11 at a location where the contact portion 25 is not provided. Accordingly, the electrolyte can be passed through the gap to both sides of the heat sink main body 23 to transfer ions, and the battery efficiency can be improved.

  According to this heat radiating plate 26, heat generated in the positive electrode plate 18 and the negative electrode plate 20 can be suitably conducted from the heat radiating plate body 23 to the outside of the container 11 through the contact portion 25. At this time, the contact portion 25 is in surface contact with the inner surface of the container 11 at the contact surface 25A, and is further pressed against the heat radiating plate main body 23 so as to be in close contact with the gap, so that heat can be efficiently transferred to the container 11. It is possible to dissipate heat through.

  Moreover, it is good also as a heat sink of the structure which has a hole which can distribute | circulate electrolyte solution. This hole may be perforated by machining or the like, or a heat sink made of a porous material may be selected. According to this heat sink, the electrolyte can be passed through the holes, and ions can be transferred between the positive electrode plate 18 and the negative electrode plate 20 on both sides of the heat sink, thereby improving heat dissipation. However, the battery efficiency can be improved.

  Further, an insulating film may be provided on the surface of the heat sink. In this case, even if the heat radiating plate comes into contact with the positive electrode plate 18 or the negative electrode plate 20, no current is supplied, so the number of the positive electrode plates 18 and the negative electrode plates 20 can be increased.

DESCRIPTION OF SYMBOLS 10 Secondary battery 11 Container 12 Laminated body 13 Extinguishing agent 18 Positive electrode plate 20 Negative electrode plate 21 Separator 22 Extinguishing agent accommodation structure

Claims (3)

A container for storing an electrolyte inside;
A laminated body disposed in the container having sheet-like positive and negative electrode plates alternately stacked, and a separator disposed between the positive electrode plate and the negative electrode plate;
A fire extinguisher containing structure that is interposed between any of the positive electrode plate and the negative electrode plate of the laminate and contains a fire extinguishing agent inside and destroys it at a predetermined temperature;
A secondary battery comprising:   The secondary battery according to claim 1, wherein the fire extinguishing agent-accommodating structure is disposed at a central portion in the stacking direction of the stacked body.   The secondary battery according to claim 1, wherein the fire extinguisher containing structure is configured to be destroyed at a temperature of 100 to 300 ° C. to release the fire extinguisher.

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