JP2019061735A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of restraining firing, by preventing concatenation of overheat state between power storage elements.SOLUTION: A power storage device 100 includes multiple power storage elements 1, and a cooling module 30 for cooling the power storage elements 1. The cooling module 30 is placed at least between the power storage elements 1, and has a cooling part 31 incorporating a flame-resistant agent, and cooling the power storage elements 1 by endotherm of the flame-resistant agent at the time of evaporation. In the cooling part 31 in contact with the power storage element 1 that generated heat, the power storage elements 1 are cooled well by the heat of vaporization when the incorporated flame-resistant agent evaporates, and concatenation of overheat state is prevented between the power storage elements 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage device provided with a plurality of power storage elements.

  A chargeable / dischargeable storage element is used in various devices such as mobile phones and automobiles. Above all, vehicles powered by electrical energy such as electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) require large amounts of energy, so they are equipped with a large-capacity storage device equipped with a plurality of storage elements. There is.

  In such a storage device, when the temperature of any one storage element is excessively increased due to some cause, which is not a normal use state, the heat of the storage element is conducted to the adjacent storage element to cause adjacent storage. The element is heated. Thereby, when the active material of the electrode of the adjacent storage element is heated to the self-heating temperature or more, the adjacent storage element is also heated by the self-heating and further heats the storage element next to the storage element. A large number of storage elements may overheat.

  When using a storage element in which a metal case is covered with a resin film, when the storage element is overheated, the resin film is melted and the metal cases are in contact with each other to promote heat conduction, resulting in an overheat state. Chains are likely to occur. In particular, when a metal case is used as an electrode, or when the metal case has an abnormal potential due to some abnormality, an abnormal current is applied to an adjacent storage element by being in electrical contact with the case of the adjacent storage element. It may cause an overheat condition.

  Patent Document 1 discloses a technique for suppressing conduction of heat of a storage element to an adjacent storage element.

When the storage element is a non-aqueous electrolyte secondary battery, it is widely known that an electrolyte such as lithium hexafluorophosphate (LiPF ₆ ) as a non-aqueous electrolyte is dissolved in a non-aqueous solvent containing ethylene carbonate as a main component. It is done. These non-aqueous solvents are generally volatile and flammable. Therefore, in the power storage device, suppression of ignition is required.
In Patent Document 2, the non-aqueous electrolyte contains a non-cyclic fluorinated ether having at least one —CF ₂ H group at the end, a cyclic carbonate compound having a carbon-carbon π bond, and sultone, It is disclosed to make the water electrolyte flame retardant.
In Patent Document 3, the non-aqueous electrolyte contains a fluorinated phosphoric acid ester having a carbon number of 3 or less and / or a fluorinated linear carbonate, and the proportion of these non-aqueous electrolytes in the solvent is 15 It is disclosed that the non-aqueous electrolyte is made incombustible by setting the amount to 30% by mass.

JP, 2015-195149, A Patent No. 5092416 Patent No. 5842873 gazette

In the power storage device of Patent Document 1, the conduction of heat between the power storage elements is suppressed by the partition member formed of the mica accumulation material.
In recent years, it has been required to further increase the capacity of the storage element and the storage device. When the capacity of the storage element is increased, the energy and heat released from the storage element when the storage element is overheated are also very large. The heat insulation can be enhanced by increasing the thickness of the air layer or the partition member between the storage elements, but with such a method, the energy density of the storage device decreases. Therefore, there is a need for new measures that can prevent the chain of overheated states between storage elements without reducing the energy density.
It is necessary to mix a large amount of fluorinated carbonate etc. in order for the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery to exhibit sufficient flame retardancy for the purpose of preventing the ignition of the electricity storage device, but good battery characteristics There is a limit to the amount of fluorinated carbonate added in order to obtain

  An object of the present invention is to provide a power storage device that can prevent a chain of overheat states between storage elements and can suppress ignition.

  A power storage device according to the present invention includes a plurality of power storage elements, and a cooling unit which is disposed between at least the power storage elements, incorporates a flame retardant, and cools the power storage element by heat of vaporization of the flame retardant. It is characterized by having.

According to the present invention, in the cooling unit in contact with the heated storage element, the built-in flame retardant absorbs heat from the storage element and evaporates, whereby the storage element is cooled well. Since the cooling unit is disposed at least between the storage elements, the conduction of heat to the storage element adjacent to the generated storage element is suppressed. Therefore, chained heat transfer between storage elements is prevented.
Since the flame retardant is contained in the cooling unit, it is vaporized and then liquefied in the cooling unit and reused for cooling the storage element, whereby the storage element is efficiently cooled.
When the flame retardant is vaporized and released from the cooling unit and the flammable component is released from the storage element, the flammable component is made into a flame retardant by the flame retardant, and the storage device prevents or suppresses the ignition. Ru.

It is a perspective view of an electrical storage element. It is a perspective view of the electrical storage apparatus which concerns on 1st Embodiment. It is a perspective view of a cooling module. It is the IV-IV sectional view taken on the line of FIG. It is an explanatory view explaining cooling by a cooling module when a storage element generates heat. It is an explanatory view explaining control of ignition by a flame retardant. It is a perspective view of a cooling module concerning a 2nd embodiment. It is explanatory drawing in the case where internal space is connected in 2nd Embodiment. It is an explanatory view explaining control of ignition by a flame retardant. It is a perspective view of a cooling module concerning a 3rd embodiment. It is a perspective view of the electrical storage apparatus which concerns on 4th Embodiment.

Hereinafter, the present invention will be specifically described based on the drawings showing the embodiments thereof.
First Embodiment
FIG. 1 is a perspective view of the storage element 1. Hereinafter, although the case where the storage element 1 is a lithium ion secondary battery will be described, the storage element 1 is not limited to a lithium ion secondary battery.
The storage element 1 includes a case 11 having a cover plate 2 and a case main body 3, a positive electrode terminal 4, a negative electrode terminal 8, gaskets 6 and 10, a rupture valve 20, a current collector and an electrode body (not shown).

  The case 11 is made of, for example, a metal such as aluminum, an aluminum alloy, stainless steel, or a synthetic resin, has a rectangular parallelepiped shape, and accommodates an electrode body and an electrolytic solution (not shown). Alternatively, the case may be a pouch case using a laminate sheet.

The positive electrode terminal 4 has a shaft portion penetrating the lid plate 2 and a plate portion provided at one end of the shaft portion.
The positive electrode terminal 4 is provided so as to pass through the lid plate 2 in a state in which the inner surface of the plate portion and the shaft portion are covered with the gasket 6 and insulated.

  The negative electrode terminal 8 has a shaft portion penetrating the cover plate 2 and a plate portion provided at one end of the shaft portion. The negative electrode terminal 8 is provided so as to penetrate the lid plate 2 in a state in which the inner surface of the plate portion and the shaft portion are covered by the gasket 10 and the state is insulated.

The electrode body is a laminated type having a main body in which a plurality of positive electrode plates and negative electrode plates are alternately stacked via a separator to form a rectangular parallelepiped shape, and a positive electrode tab and a negative electrode tab extending from the main body toward the lid plate 2 May be The positive electrode tab is connected to the positive electrode terminal 4 via a current collector. The negative electrode tab is connected to the negative electrode terminal 8 via a current collector.
The electrode body may be a wound type obtained by winding a positive electrode plate and a negative electrode plate in a flat shape via a separator.
The electrode body is more preferably a laminated type in which the swelling (the swelling of the outer case such as a metal case such as case 11 and a pouch case) due to charge and discharge cycles is small. Since there is little swelling of the exterior body accompanying a charge / discharge cycle, it is suppressed that the exterior body presses the cooling part 31 at the time of normal use.

The positive electrode plate is obtained by forming a positive electrode active material layer on a positive electrode substrate foil that is a plate-like (sheet-like) or long strip-like metal foil made of aluminum, an aluminum alloy or the like. The negative electrode plate is obtained by forming a negative electrode active material layer on a negative electrode substrate foil that is a plate-like (sheet-like) or long strip-like metal foil made of copper and copper alloy or the like. The separator is a microporous sheet made of a synthetic resin.
As the positive electrode active material used in the positive electrode active material layer or the negative electrode active material used in the negative electrode active material layer, known materials can be used appropriately as long as the positive electrode active material or the negative electrode active material can occlude and release lithium ions. .

Examples of the positive electrode active material include polyanion compounds such as LiMPO ₄ , Li ₂ MSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), titanium Using lithium spinel compounds such as lithium oxalate and lithium manganate; and lithium transition metal oxides such as LiMO 2 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) it can.

As the negative electrode active material, for example, lithium metal, lithium alloy (lithium-aluminum, lithium-silicon, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium such as wood alloy, etc.) Other than these, alloys capable of absorbing and desorbing lithium, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon etc.), metal oxides (SiO etc.), lithium metal oxides Substances (Li ₄ Ti ₅ O ₁₂ etc.), polyphosphoric acid compounds and the like.

  The rupture valve 20 has a rupture 200 formed by partially reducing the plate thickness. When the internal pressure of the storage element 1 rises, it breaks along the fractured portion 200 to form a tongue-like portion, and the portion jumps outward to form an opening in the lid plate 2.

FIG. 2 is a perspective view of the power storage device 100 according to the present embodiment, and FIG. 3 is a perspective view of the cooling module 30.
Power storage device 100 includes a plurality of power storage elements 1, a cooling module 30 for cooling power storage elements 1, and a case 40 for storing power storage elements 1 and cooling module 30. Although three storage elements 1 are accommodated in FIG. 2, the number of storage elements 1 is not limited to three.
The case 40 has a box shape and is made of, for example, an insulating material such as a synthetic resin. Case 40 arrange | positions the electrical storage element 1 and the cooling module 30 grade | etc., In a predetermined position, and protects them from a shock. The case 40 is provided with an external electrode terminal (not shown) for charging electricity from the outside and discharging the electricity to the outside.

The cooling module 30 may be made of, for example, a metal such as aluminum having good thermal conductivity and heat resistance, or may be subjected to an insulating process by forming an insulating film on the surface or the like.
As shown in FIG. 3, the cooling module 30 includes a plate-like cooling unit 31, connection units 32 and 33 connecting the cooling unit 31, and an internal pressure release valve 34. The two cooling units 31 are interposed between the long side surfaces of the adjacent storage element 1, and the other two cooling units 31 abut on the long side surfaces of the storage element 1 at both ends. Here, the long side surface is provided to extend upward from the long side of the bottom surface of the storage element 1 in FIG. 1, and means the side surface having the largest area among the side surfaces. An internal pressure release valve 34 is provided at the center of the upper surface of each cooling unit 31.
Cooling portion 31 may be provided corresponding to the number of storage elements 1 or may be provided between storage elements 1 and further in contact with the long side surfaces of storage elements 1 at both ends. .
The installation position of the internal pressure release valve 34 is also not limited to the central portion of the upper surface of the cooling unit 31.
The internal pressure release valve 34 can be installed at a position where ignition can be effectively prevented when a flame retardant L described later is ejected. As shown in FIG. 2, the rupture valve 20 of the storage element 1 and the internal pressure release valve 34 of the cooling unit 31 may face in the same direction. The internal pressure release valve 34 may face upward in the direction of gravity.

The cooling unit 31 is hollow.
The cooling unit 31 contains a flame retardant L.
An upper portion of one end of the long side surface of the adjacent cooling unit 31 is connected by the connecting unit 32. The connecting portion 32 is hollow, and the gas in the connected cooling portion 31 is configured to flow in the connecting portion 32.
The lower part of one end of the long side face of the adjacent cooling part 31 is connected by the connecting part 33. The connection portion 33 is hollow, and the flame retardant L in the connected cooling portion 31 is configured to flow in the connection portion 33.
That is, the cooling space 31, the connection part 32, and the connection part 33 are in communication with the internal space.

  In addition, the cooling unit 31 on the outside can be omitted. For example, in the case where the number of storage elements 1 is five, four cooling units 31 are disposed between the storage elements 1, and the four cooling units 31 are connected by the connection units 32 and 33. The long side of the outer storage element 1 is brought into contact with the side of the case 40. The cooling efficiency is better if the outer cooling portion 31 is provided.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.
The internal pressure release valve 34 is a circular groove, and as shown in FIG. 4, the thickness of the bottom of the groove is thinner than the thickness of the other part. The internal pressure release valve 34 is formed by cutting, pressing or the like. When the internal pressure release valve 34 is formed by cutting, a device capable of cutting a curved surface such as a three-dimensional NC is used. When the internal pressure release valve 34 is formed by press processing, it is formed so as to press an imprint by a mold having a protrusion.

The flame retardant L develops flame retardance with respect to the flammable gas by vaporization. The flame retardant L preferably has high heat of vaporization, corrosion resistance, and does not generate toxic gas.
The flame retardant L preferably contains at least one of non-cyclic fluorinated ether, fluorinated phosphoric acid ester, and phosphazene derivative. These have high flame retardancy by being vaporized.

The non-cyclic fluorinated ether is more preferably represented by the following formula (1).
CX _3-j H _j- (CF _x H _2-x ) _m -O- (CF _y H _2-y ) _n -CF _3-k H _k (1)
(Where X is F or CF _3, j, k, m, n, x and y are integers, 0 ≦ j ≦ 3, 0 ≦ k ≦ 3, 1 ≦ m ≦ 3, 0 ≦ n ≦ 1, 0 ≦ x ≦ 2, 0 ≦ y ≦ 2, and includes at least one fluorine atom)
Specifically, for example, HCF ₂ CF ₂ CH ₂ OCF ₂ CF ₂ H, HCF ₂ CF ₂ OCH ₂ CF ₃ , CF ₃ CF ₂ CH ₂ OCF ₂ CF ₂ H, HCF ₂ CF ₂ CH ₂ OCHF ₂ , CF ₃ CF ₂ CH ₂ OCF ₂ H, (CF ₃ ) ₂ CHCF ₂ OCF ₂ H, CF ₃ CHFCF ₂ CH ₂ OCHF ₂ or the like alone or a mixture of two or more thereof can be mentioned, but it is limited thereto It is not a thing.

  The fluorinated phosphate is more preferably represented by the following formula (2).

(However, j, k, l, m, n, o, x, y and z are integers, and 0 ≦ j ≦ 3, 0 ≦ k ≦ 3, 0 ≦ l ≦ 3, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1, 0 ≦ o ≦ 1, 0 ≦ x ≦ 2, 0 ≦ y ≦ 2, 0 ≦ z ≦ 2, and includes at least one fluorine atom)

  The phosphazene derivative is more preferably represented by the following formula (3).

(Wherein, R _{1 to} R _{6 each} represents an identical or non-identical hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with a fluorine atom, C1-C10 alkoxy group, a C1-C10 alkoxy group substituted by the fluorine atom is shown.)

The phosphazene derivative is further a fluorine-containing phosphazene derivative in which at least one of R _{1 to} R ₆ is either a fluorine atom, an alkyl group substituted with a fluorine atom, or an alkoxy group substituted with a fluorine atom. preferable.

  Among the fluorine-containing phosphazene derivatives, monoethoxypentafluorocyclotriphosphazene represented by the following formula 3 and monophenoxypentafluorocyclotriphosphazene represented by the following formula 4 are particularly preferable.

  The storage amount of the flame retardant L is based on the internal volume of the cooling unit 31 and the connecting parts 32 and 33, the assumed heat generation temperature of the storage element 1, the volume when the flame retardant L is vaporized, etc. The cooling unit 31 is set so as not to be damaged.

FIG. 5 is an explanatory view for explaining cooling by the cooling module 30 when the storage element 1 generates heat.
It is assumed that the flame retardant agent L is accommodated in the cooling module 30, and the storage element 1 at the center generates heat.
Heat is conducted from the storage element 1 that has generated heat to the cooling units 31 on both sides, and the flame retardant L in the cooling unit 31 evaporates (FIG. 5A). When the flame retardant L evaporates, the heat of vaporization is taken, and the storage element 1 is rapidly cooled by the endothermic reaction. The liquid amount of the flame retardant L in the cooling unit 31 decreases.

  The gas in the cooling unit 31 flows to the upper part by thermal convection and travels through the connecting units 32 and 32 to the cooling unit 31 on the lower temperature side (FIG. 5B). The gas condenses in the outer cooling unit 31, and the liquid amount of the flame retardant L in the outer cooling unit 31 increases.

  Since the amount increased in the outer cooling portion 31, the flame retardant L flows to the inner cooling portion 31 through the connecting portion 33, and the liquid amounts of the flame retardant L in the four cooling portions 31 become equal (see FIG. 5C). The recycled flame retardant L also absorbs the heat of the storage element 1, evaporates, and circulates in the same manner as described above.

FIG. 6 is an explanatory view illustrating suppression of ignition by the flame retardant.
When thermal runaway in which the temperature of the storage element 1 rises rapidly occurs, the amount of heat absorption from the storage element 1 increases, and the evaporation amount of the flame retardant L increases. When the internal pressure of the cooling unit 31 in contact with the storage element 1 reaches a predetermined value or more, the internal pressure release valve 34 of the cooling unit 31 is opened, and the vaporized flame retardant L is released to the outside. In FIG. 6, the internal pressure release valve 34 of the cooling unit 31 on both sides of the storage element 1 is opened, and the flame retardant L is released. When the internal pressure of the outer cooling unit 31 also reaches a predetermined value or more, the internal pressure release valve 34 opens.
When the internal pressure of the storage element 1 reaches a predetermined value or more, the rupture valve 20 is opened, and the flammable component of the volatilized electrolyte solution is released to the outside. The flammable component is rendered incombustible by the flame retardant L to prevent ignition.

  As described above, the power storage device 100 of the present embodiment is disposed between the plurality of power storage elements 1 and at least the power storage element 1 and incorporates the flame retardant L, and the heat of vaporization of the flame retardant L And a cooling unit 31 for cooling the storage element 1.

According to the above configuration, the heat of vaporization is taken away when the flame retardant L in the cooling unit 31 in contact with the storage element 1 that generates heat is vaporized, so the storage element 1 is cooled well. Since the cooling unit 31 is disposed at least between the storage elements 1, the conduction of heat to the storage elements 1 adjacent to the generated storage element 1 is suppressed. Even when the heat is transferred to the adjacent storage element 1 without the cooling unit 31, the long side facing the storage element 1 that generates heat is cooled by the cooling unit 31. Therefore, the heat transfer to the storage element 1 in a chained manner is suppressed.
The structure of cooling of the cooling module 30 is simple, and the storage element 1 can be cooled even when a small amount of heat is generated.
Since the flame retardant L is contained in the cooling unit 31, after being vaporized, it is liquefied in the cooling unit 31, is reused for cooling the storage element 1, and efficiently cools the storage element 1.

  In the power storage device 100 described above, the flame retardant agent L develops flame retardance with respect to a flammable gas by vaporization.

  According to the above configuration, when the flame retardant agent L absorbs heat from the heated storage element 1 to vaporize and is released from the internal pressure release valve 34, it mixes with the flammable component released from the storage element 1 and is flammable. The components are incombustible and ignition is prevented in power storage device 100.

  In the storage device 100 described above, the flame retardant L includes at least one of non-cyclic fluorinated ether, fluorinated phosphate ester, and phosphazene derivative.

  According to the above configuration, the flame retardant L has high flame retardancy by being vaporized.

  In the power storage device 100 described above, the cooling module 30 has a connecting portion that connects the plurality of cooling portions 31 such that the internal space is in communication.

According to the above configuration, the gas generated by the vaporization of the flame retardant L in the one cooling unit 31 in contact with the heated storage element 1 passes through the insides of the connecting portions 32 and 33 by heat convection, and the other It flows to the cooling unit 31. The gas is liquefied in the other cooling unit 31 and flows to the one cooling unit 31, and the flame retardant L circulates.
Therefore, the flame retardant L is reused to cool the storage element 1 and the storage element 1 is efficiently cooled.
In addition, when the heated gas flows from one cooling unit 31 to the other cooling unit 31 via the connection units 32 and 33, the long side surface of the one storage element 1 in contact with the one cooling unit 31, and the other The temperature difference between the long side in contact with the cooling unit 31 and the temperature difference between the storage elements 1 are reduced. And, by the circulation of the gas and the flame retardant L, the temperature difference between the plurality of storage elements 1 can be reduced and the cooling can be performed efficiently. Even when the heat generation is not abnormal and occurs to a low degree, the heat from the storage element 1 is favorably dissipated by the cooling unit 31, and the temperature difference between the storage elements 1 is reduced.

  In the storage device 100 described above, the cooling unit 31 includes an internal pressure release valve 34 that releases the internal pressure when the internal pressure of the cooling unit 31 exceeds a predetermined pressure.

According to the above configuration, when the evaporation amount of the flame retardant L is large and the internal pressure of the cooling unit 31 exceeds the predetermined pressure, the internal pressure release valve 34 is opened, and the gas is released to the outside. It is possible to prevent the cooling unit 31 from expanding due to the release of the gas and the storage element 1 being pressed.
When the temperature of the storage element 1 rises sharply, the amount of heat absorption from the storage element 1 increases, and the evaporation amount of the flame retardant L increases. When the internal pressure reaches a predetermined value or more, the cooling portion 31 is opened, and the vaporized flame retardant L is released to the outside. When the internal pressure of the storage element 1 reaches a predetermined value or more, the storage element 1 is opened, and the flammable component of the volatilized electrolyte solution is released to the outside. The flammable component is rendered incombustible by the flame retardant L to prevent ignition.

Even when the storage element 1 at the end rather than the center generates heat, the cooling unit 31 absorbs heat in the same manner as described above, and the storage element 1 is rapidly cooled. The long side of the storage element 1 adjacent to the storage element 1 that generates heat is also cooled rapidly, and the heat transfer from the storage element 1 that generates heat is suppressed, and the chain of superheat states between storage elements is prevented.
In addition, the structure of the cooling module 30 is not limited to the structure of FIG. The connection portion may be provided such that the rectangular tube passes through the upper portion and the lower portion of one end of each of the four cooling portions 31 in the longitudinal direction.

Second Embodiment
FIG. 7 is a perspective view of the cooling module 35 according to the second embodiment. In the figure, the same parts as in FIG. 3 are assigned the same reference numerals and detailed explanations thereof will be omitted.
The cooling module 35 includes four cooling units 31 and a cooling plate 36.
Unlike the first embodiment in which the four cooling units 31 are connected by the connecting units 32 and 33, the cooling module 35 is in contact with the cooling plate 36 with end surfaces 31a of the four cooling units 31. The flame retardant L is accommodated in the cooling unit 31 as in the first embodiment.
The cooling unit 31 and the cooling plate 36 may or may not be in communication with each other in the internal space.

FIG. 8 is an explanatory view of the case where the internal space is communicated in the present embodiment. The storage element 1 is inserted between the cooling units 31, and the flame retardant agent L is accommodated in the cooling units 31 and the cooling plate 36.
When the central storage element 1 generates heat, the flame retardant L in the cooling unit 31 in contact with the storage element 1 takes vaporization heat from the storage element 1 and evaporates, as in the first embodiment. Is quenched. The liquid amount of the flame retardant L in the cooling unit 31 decreases. The generated gas flows to the other cooling unit 31 through the cooling plate 36, and the flame retardant L generated by condensation flows to the cooling unit 31 in which the liquid amount of the flame retardant L is reduced. The flame retardant L also absorbs heat to cool the storage element 1, and the generated gas circulates as described above. The cooling plate 36 also cools the side surface of the storage element 1 in contact.

  When the internal space is not communicated, when the storage element 1 generates heat, the flame retardant L in the cooling unit 31 in contact with the storage element 1 takes vaporization heat from the storage element 1 and evaporates, and the storage element 1 Be quenched. The generated gas is cooled by the cooling plate 36 and condensed to the flame retardant L. The flame retardant L absorbs heat from the storage element 1 and is vaporized, whereby the storage element 1 is cooled.

  Also in the present embodiment, the conduction of heat to the storage element 1 adjacent to the generated storage element 1 is suppressed by the cooling module 35 having a simple structure, and the heat is transferred to the adjacent storage element 1 in a chained manner. Be suppressed.

FIG. 9 is an explanatory view illustrating suppression of ignition by the flame retardant L. As shown in FIG.
When thermal runaway in which the temperature of the storage element 1 rises rapidly occurs, the amount of heat absorption from the storage element 1 increases, and the evaporation amount of the flame retardant L increases. When the internal pressure of the cooling unit 31 in contact with the storage element 1 reaches a predetermined value or more, the internal pressure release valve 34 is opened, and the vaporized flame retardant L is released to the outside. When the internal pressure of the storage element 1 reaches a predetermined value or more, the rupture valve 20 is opened, and the flammable component of the volatilized electrolyte solution is released to the outside.
The flammable component is rendered incombustible by the flame retardant L to prevent ignition.

  In the power storage device of the present embodiment, each of the power storage elements 1 is formed in a rectangular parallelepiped shape, and the plurality of power storage elements 1 are in contact with a surface different from the long side facing the cooling portion 31 of each of the power storage elements 1. A cooling plate 36 is provided to cool the heat source, and heat can be conducted between the cooling plate 36 and the cooling unit 31.

  According to the above configuration, heat is conducted between the cooling plate 36 and the cooling unit 31, so that the heat is dissipated well. The gas produced by the vaporization of the flame retardant L is cooled and liquefied, and the flame retardant L absorbs heat from the storage element 1 again to cool the storage element 1.

  In the power storage device described above, the cooling plate 36 and the cooling unit 31 are integrated so that the flame retardant L or a gas vaporized of the flame retardant L can circulate.

According to the above configuration, the gas generated by the vaporization of the flame retardant L in the one cooling unit 31 in contact with the heated storage element 1 passes through the inside of the cooling plate by thermal convection, and the other cooling unit 31 Flow to The gas is liquefied in the other cooling unit 31 and flows to the one cooling unit 31, and the flame retardant L circulates.
Therefore, the flame retardant L is reused to cool the storage element 1 and cools the storage element 1 efficiently.
Further, the temperature difference between one long side surface and the other long side surface of one storage element 1 is reduced, and the temperature difference between storage elements 1 is reduced. And, by the circulation of the gas and the flame retardant L, the temperature difference between the plurality of storage elements 1 can be reduced and the cooling can be performed efficiently. Even when the heat generation is not abnormal and occurs to a low degree, the heat from the storage element 1 is favorably dissipated by the cooling unit 31, and the temperature difference between the storage elements 1 is reduced.

Third Embodiment
FIG. 10 is a perspective view of the cooling module 37 according to the third embodiment. In the figure, the same parts as in FIG. 3 are assigned the same reference numerals and detailed explanations thereof will be omitted.
The cooling module 37 of the third embodiment has a configuration in which the bottom surfaces 31 b of the four cooling sections 31 of the cooling module 30 of the first embodiment are in contact with the cooling plate 38. The cooling unit 31 contains a flame retardant L (not shown) as in the first embodiment.
The internal space of the cooling unit 31 and the cooling plate 38 is not communicated with each other. The cooling plate 38 may be configured to be cooled by a cooling device (not shown).

  When the central storage element 1 generates heat, the flame retardant agent L in the cooling unit 31 in contact with the storage element 1 evaporates as in the first embodiment, and the storage element 1 is cooled by the vaporization heat at the time of evaporation. Be done. The generated gas flows through the other cooling unit 31, and the flame retardant L generated by condensation flows to the cooling unit 31 with a small amount of liquid of the flame retardant L. The cooling plate 38 cools the bottom of the storage element 1 and also cools the cooling unit 31. The flame retardant L in the cooling unit 31 in contact with the storage element 1 also absorbs heat from the storage element 1 and evaporates to cool the storage element 1.

  Also in the present embodiment, similarly to the first embodiment and the second embodiment, the conduction of heat to the storage element 1 adjacent to the generated storage element 1 is suppressed by the cooling module 37 having a simple structure, and further adjacent Heat transfer to the storage element 1 in a continuous manner is suppressed.

When the temperature of the storage element 1 rises sharply, the amount of heat absorption from the storage element 1 increases, and the evaporation amount of the flame retardant L increases. When the internal pressure reaches a predetermined value or more, the internal pressure release valve 34 is opened, and the vaporized flame retardant L is released to the outside. When the internal pressure of the storage element 1 reaches a predetermined value or more, the rupture valve 20 is opened, and the flammable component of the volatilized electrolyte solution is released to the outside.
The flammable component is rendered incombustible by the flame retardant L to prevent ignition.

Fourth Embodiment
FIG. 11 is a perspective view of a power storage device 101 according to the fourth embodiment. In the figure, the same parts as in FIG. 2 are assigned the same reference numerals and detailed explanations thereof will be omitted.
Unlike the power storage device 100 according to the first embodiment, the power storage device 101 does not have the connecting portions 32 and 33 that connect the cooling portion 31. Cooling unit 31 is independently disposed between storage element 1 or between storage element 1 and the inner surface of case 40. The cooling unit 31 contains a flame retardant L (not shown).

  When the storage element 1 generates heat, the flame retardant L in the cooling unit 31 in contact with the storage element 1 takes vaporization heat from the storage element 1 to evaporate and the storage element 1 is rapidly cooled. The generated gas is convective, cooled by the outside air and / or the outside air of the power storage device 101 and condensed to the flame retardant L. The flame retardant L absorbs heat from the storage element 1 and is vaporized, whereby the storage element 1 is cooled.

  In the present embodiment, since the cooling unit 31 intervenes between the storage devices 1, the storage device 1 that generates heat is cooled by the cooling units 31 on both sides as in the first embodiment, and transmission to the adjacent storage devices 1 is performed. Heat is suppressed. Even when the heat is transferred to the adjacent storage element 1 without the cooling unit 31, the long side facing the storage element 1 that generates heat is cooled by the cooling unit 31. Therefore, the heat transfer to the adjacent storage elements 1 in a chained manner is suppressed.

When the temperature of the storage element 1 rises sharply, the amount of heat absorption from the storage element 1 increases, and the evaporation amount of the flame retardant L increases. When the internal pressure reaches a predetermined value or more, the internal pressure release valve 34 is opened, and the vaporized flame retardant L is released to the outside. When the internal pressure of the storage element 1 reaches a predetermined value or more, the rupture valve 20 is opened, and the flammable component of the volatilized electrolyte solution is released to the outside.
The flammable component is rendered incombustible by the flame retardant L to prevent ignition.

The present invention is not limited to the contents of the embodiments described above, and various modifications can be made within the scope of the claims. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims is also included in the technical scope of the present invention.
In the first to fourth embodiments, the case where the positive electrode terminal 4 and the negative electrode terminal 8 of the storage element 1 are arranged to face upward is described, but the present invention is not limited to this. Even when the positive electrode terminal 4 and the negative electrode terminal 8 are arranged to face sideways, the cooling structure of the present invention can be applied.
Moreover, although the case where the electrical storage element 1 is a lithium ion secondary battery is demonstrated, the electrical storage element 1 is not limited to a lithium ion secondary battery. The storage element 1 may be another secondary battery having an organic solvent, may be a primary battery, or may be an electrochemical cell such as a capacitor.
The power storage device according to the present invention can be particularly suitably used as a power source for a vehicle. In addition, the power storage device according to the present invention includes a power storage system (large-scale power storage system, household small-scale power storage system), a distributed power supply system combined with natural energy such as sunlight or wind power, a power supply system for railways, unmanned carrier It can also be suitably used in industrial applications such as power supply systems for (AGV).

DESCRIPTION OF SYMBOLS 1 storage element 2 cover plate 3 case main body 4 positive electrode terminal 8 negative electrode terminal 6, 10 gasket 11 case 20 bursting valve 30, 35, 37 cooling module 31 cooling unit 32, 33 connection part 34 internal pressure release valve 36, 38 cooling plate 40 case 100, 101 Power storage device

Claims (7)

A plurality of storage elements,
A power storage device, comprising: a cooling unit disposed at least between the power storage elements, containing a flame retardant, and cooling the power storage element by heat of vaporization of the flame retardant.   The power storage device according to claim 1, wherein the flame retardant expresses flame retardance by being vaporized.   The power storage device according to claim 2, wherein the flame retardant includes at least one of non-cyclic fluorinated ether, fluorinated phosphoric acid ester, and phosphazene derivative.   The power storage device according to any one of claims 1 to 3, further comprising a connecting portion connecting a plurality of cooling portions so that the internal space is in communication. Each of the storage elements is formed in a rectangular shape;
A cooling plate for cooling a plurality of the storage elements in contact with a surface different from the long side face of the storage elements facing each other;
The power storage device according to any one of claims 1 to 4, wherein heat can be conducted between the cooling plate and the cooling unit.   The power storage device according to claim 5, wherein the cooling plate and the cooling unit are integrated such that the flame retardant or the gas vaporized of the flame retardant can circulate.   The electricity storage according to any one of claims 1 to 6, wherein the cooling unit has an internal pressure release valve that releases the internal pressure when the internal pressure of the cooling unit exceeds a predetermined pressure. apparatus.

Images