JP3191519U - Power storage device - Google Patents

Abstract

Provided is a power storage device capable of reducing a temperature difference between a plurality of power storage cells and having high reliability.
A power storage device having a plurality of power storage cells each having a positive electrode, a negative electrode, and an exterior body that accommodates an electrolyte solution, the heat insulating member being provided between adjacent power storage cells. including.
[Selection] Figure 1

Description

  The present invention relates to an electricity storage device.

  A power storage cell that is a constituent element of a power storage device is formed by sealing, for example, an electrode body in which a predetermined number of layers are stacked while a sheet-like positive electrode and a negative electrode are opposed to each other via a separator, together with an electrolytic solution. In order to reduce the size and increase the energy of the electricity storage device, a plurality of such sealed electricity storage cells are used, for example, connected in series (see Patent Document 1).

JP 2006-228610 A

  The power storage cell generates heat due to charging / discharging, but when a plurality of power storage cells are stacked as described above, a temperature difference is generated between the power storage cell disposed at the center and the power storage cell disposed at the end. More specifically, the energy storage cell disposed in the central part is more likely to store heat due to the heat generated by the energy storage cells disposed on both sides of the energy storage cell, compared to the energy storage cell disposed at the end, The temperature rise tends to increase. When a temperature difference occurs between the storage cells during charging / discharging in this way, the deterioration rate and charge / discharge characteristics of the storage cell change (for example, the output voltage of the storage cell changes due to temperature change), and the entire storage device The reliability will be reduced.

  One of the objects according to some aspects of the present invention is to provide a power storage device that can reduce a temperature difference between a plurality of power storage cells and has high reliability.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the electricity storage device according to the present invention is:
A power storage cell having a positive electrode, a negative electrode, and an exterior body in which an electrolytic solution is housed, is a power storage device in which a plurality of layers are stacked,
A heat insulating member provided between the adjacent storage cells is included.

[Application Example 2]
In application example 1,
The exterior body may be a laminate film.

[Application Example 3]
In application example 1 or 2,
The power storage cells and the heat insulating members can be alternately stacked.

[Application Example 4]
In any one of Application Examples 1 to 3,
A heat sink disposed between the electricity storage cell and the heat insulating member may be further included.

[Application Example 5]
In application example 4,
A heat sink connected to the heat sink may be further included.

[Application Example 6]
In application example 5,
A cooling unit for cooling the heat sink may be further included.

  According to the electricity storage device of the present invention, the heat insulating member is provided between adjacent electricity storage cells. Thereby, the temperature rise of the electrical storage cell arrange | positioned in the center part among the laminated | stacked electrical storage cells can be suppressed, and the temperature difference between electrical storage cells can be made small (it equalizes). Therefore, the electricity storage device according to the present invention can have high reliability.

The perspective view which shows typically the electrical storage device which concerns on this embodiment. Sectional drawing which shows typically the electrical storage device which concerns on this embodiment. Sectional drawing which shows typically the electrical storage device which concerns on this embodiment. Sectional drawing which shows typically the electrical storage cell which concerns on this embodiment. The perspective view which shows typically the electrical storage device which concerns on the 1st modification of this embodiment. Sectional drawing which shows typically the electrical storage device which concerns on the 1st modification of this embodiment. The perspective view which shows typically the electrical storage device which concerns on the 2nd modification of this embodiment. Sectional drawing which shows typically the electrical storage device which concerns on the 2nd modification of this embodiment. The perspective view which shows typically the electrical storage device which concerns on the 3rd modification of this embodiment. Sectional drawing which shows the electrical storage device which concerns on the comparative example 1 typically. 3 is a graph showing the results of a charge / discharge test of Example 1. The graph which shows the result of the charging / discharging test of Example 2. The graph which shows the result of the charging / discharging test of the comparative example 1. 3 is a graph showing the results of an overcharge test in Example 1. The graph which shows the result of the overcharge test of the comparative example 1.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1. Power Storage Device First, a power storage device according to this embodiment will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing an electricity storage device 100 according to this embodiment. FIG. 2 is a cross-sectional view schematically showing the electricity storage device 100 according to this embodiment, and is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view schematically showing the electricity storage device 100 according to the present embodiment, and is a cross-sectional view taken along the line III-III in FIG. In FIG. 1, for convenience, the outer member 30 is shown through, and the exterior body 12 is further simplified. In FIGS. 2 and 3, for convenience, the outer member 30, the positive electrode, the negative electrode, and the like housed in the exterior body 12 are omitted.

  As shown in FIGS. 1 to 3, the electricity storage device 100 can include an electricity storage cell 10, a heat insulating member 20, and an outer shell member 30.

A plurality of storage cells 10 are provided. In the illustrated example, six power storage cells 10 are stacked, but the number thereof is not particularly limited, and can be appropriately changed according to the use of the power storage device 100. Specific examples of the storage cell 10 include a lithium ion capacitor, a secondary battery, and an electric double layer capacitor. The storage cell 10 includes an exterior body 12, a positive electrode terminal 16, and a negative electrode terminal 18.

  The exterior body 12 contains a positive electrode, a negative electrode, and an electrolytic solution. The shape of the outer package 12 is not particularly limited as long as it can accommodate the positive electrode, the negative electrode, and the electrolyte, and may be, for example, a laminate type in which two films are laminated, a box type, or a cylindrical type. 2 and 3, the exterior body 12 is illustrated as a laminate type (laminate film).

  The exterior body 12 made of a laminate film has a first flat surface 13 and a second flat surface 14 that faces away from the first flat surface 13 and has a smaller area than the first flat surface 13. In the example shown in FIG. 2 and FIG. 3, adjacent storage cells 10 are stacked such that the first flat surfaces 13 face each other or the second flat surfaces 14 face each other via the heat insulating member 20. Has been. Although not shown, adjacent storage cells 10 may be stacked such that the first flat surface 13 of one storage cell 10 and the second flat surface 14 of the other storage cell 10 face each other.

  Examples of the material of the laminate film include those in which a part of a synthetic resin such as polypropylene or nylon is used as a metal foil such as aluminum foil or copper foil. By using such a film-shaped exterior body 12, for example, compared with the case where a hard exterior body (metal can etc.) which consists of metals etc. is used, size reduction and weight reduction of the electrical storage cell 10 can be achieved. .

  The positive electrode terminal 16 and the negative electrode terminal 18 are provided so as to protrude from the exterior body 12. More specifically, the positive electrode terminal 16 and the negative electrode terminal 18 extend from the inside to the outside of the exterior body 12 in a state where the hermeticity of the exterior body is maintained. The positive terminal 16 is electrically connected to the positive electrode in the exterior body 12, and the negative terminal 18 is electrically connected to the negative electrode in the exterior body 12. Examples of the material of the positive electrode terminal 20 include aluminum. Examples of the material of the negative electrode terminal 22 include copper and nickel. The internal structure of the exterior body 12 will be described later.

  In the example shown in FIGS. 1 and 2, the positive electrode terminal 16 and the negative electrode terminal 18 of the adjacent energy storage cells 10 are connected via a wiring 17 so that the plurality of energy storage cells 10 are connected in series. Although not shown, the plurality of power storage cells 10 may be connected in parallel depending on the application of the power storage device 100.

  As shown in FIGS. 1 to 3, the heat insulating member 20 is provided between adjacent storage cells 10. It can be said that the heat insulating members 20 and the storage cells 10 are alternately stacked. In the illustrated example, five heat insulating members 20 are provided, but can be appropriately changed according to the number of power storage cells 10. The heat insulating member 20 is bonded to the exterior body 12 of the storage cell 10 via, for example, an adhesive.

  Although the shape of the heat insulation member 20 is not specifically limited, For example, it is plate shape. The thickness of the heat insulation member 20 is 0.2 mm or more and 10 mm or less, for example. As viewed from the stacking direction of the heat insulating member 20 and the power storage cell 10, the area of the heat insulating member 20 is desirably equal to or greater than the area of the power storage cell 10 (the same is true in the illustrated example). Thereby, between the electrical storage cells 10 can be thermally insulated more efficiently.

The heat insulating member 20 can have heat insulating properties, insulating properties, and nonflammability. Specifically, examples of the material of the heat insulating member 20 include polyurethane and glass wool. The heat conductivity of the heat insulating member 20 is, for example, 0.05 W / mK or more and 0.08 for foamed heat insulating materials such as polyurethane.
W / mK or less, and 0.02 W / mK or more and 0.05 W / mK or less for fiber-based heat insulating materials such as glass wool.

  As shown in FIG. 1, the outer member 30 surrounds the storage cell 10 and the heat insulating member 20. The form of the outer member 30 is not particularly limited. For example, the outer member 30 made of an adhesive tape may be wrapped around the electric storage cell 10 to enclose the electric storage cell 10 or the like, or a box-shaped case body The storage cell 10 or the like may be surrounded by housing the storage cell 10 or the like in the outer member 30 made of the above.

  The pressure-sensitive adhesive tape that can be used as the outer member 30 has adhesiveness and insulating properties, and preferably has heat dissipation properties. Thereby, the heat | fever of the electrical storage cell 10 which generate | occur | produces at the time of charging / discharging can be thermally radiated, and the temperature rise of the electrical storage cell 10 can be suppressed. As an adhesive tape, a polyester film is mentioned, for example.

  Although not shown, the storage cell 10 or the like surrounded by the adhesive tape may be further accommodated in a case body made of aluminum or the like.

  Next, the internal structure of the storage cell 10 will be described. FIG. 4 is a cross-sectional view showing one of the plurality of power storage cells 10 shown in FIG. 2, and is a cross-sectional view schematically showing the internal structure (of the outer package 12) of the power storage cell 10. Below, the case where the electrical storage cell 10 is a lithium ion capacitor is demonstrated as an example.

  The electrical storage cell 10 has the electrode laminated body 5 and the electrolyte solution (not shown) accommodated in the exterior body 12, as shown in FIG. In the illustrated example, the electrode laminate 5 and the electrolytic solution are accommodated in an exterior body 12 composed of a first laminate film 12a and a second laminate film 12b.

  The electrode laminate 5 is immersed in the electrolytic solution. The electrode laminate 5 includes a positive electrode 1, a negative electrode 2, a lithium electrode 3, and a separator 4. The positive electrode 1, the negative electrode 2, the lithium electrode 3, and the separator 4 have a sheet shape. In the illustrated example, the electrode laminate 5 is laminated in the order of the lithium electrode 3, the negative electrode 2, the positive electrode 1, the negative electrode 2, the positive electrode 1, the negative electrode 2, and the lithium electrode 3 from the inner bottom surface of the first laminate film 12a. The separator 4 is interposed between the poles and between the poles and the laminate film. In the electrode laminate 5, the positive electrode 1 and the negative electrode 2 are connected in parallel.

  The number of positive electrodes 1 and negative electrodes 2 is not particularly limited. Similarly, the number of lithium electrodes 3 and the installation location are not particularly limited. The form of the electrode laminate 5 is not limited to the example illustrated in FIG. 4. For example, a laminate sheet is formed by stacking a positive electrode, a negative electrode, a lithium electrode, and a separator, and the laminate sheet is wound. A round structure may be used.

  The positive electrode 1 includes a positive electrode current collector 1a and a positive electrode active material layer 1b. As the positive electrode current collector 1a, a porous metal foil can be used. Examples of the material of the positive electrode current collector 1a include aluminum and stainless steel. The thickness of the positive electrode current collector 1a is, for example, 15 μm or more and 50 μm or less. The positive electrode current collector 1 a is connected to the positive electrode terminal 16 through the positive electrode lead 6.

  The positive electrode active material layer 1b is formed on the positive electrode current collector 1a. In the illustrated example, the positive electrode active material layer 1b is formed on both surfaces of the positive electrode current collector 1a, but may be formed only on one surface. The thickness of the positive electrode active material layer 1b is, for example, not less than 60 μm and not more than 90 μm.

The positive electrode active material layer 1b contains a positive electrode active material. The positive electrode active material is a material that can reversibly support anions such as hexafluorophosphate (PF ₆ ⁻ ) and tetrafluoroborate (BF ₄ ⁻ ). More specifically, examples of the positive electrode active material include activated carbon and a polyacene-based material (PAS) that is a heat-treated product of an aromatic condensation polymer.

  The negative electrode 2 includes a negative electrode current collector 2a and a negative electrode active material layer 2b. As the negative electrode current collector 2a, a porous metal foil can be used. Examples of the material of the negative electrode current collector 2a include copper, stainless steel, and nickel. The thickness of the negative electrode current collector 2a is, for example, 10 μm or more and 50 μm or less. The negative electrode current collector 2 a is connected to the negative electrode terminal 18 through the negative electrode lead 7.

  The negative electrode active material layer 2b is formed on the negative electrode current collector 2a. In the illustrated example, the negative active material layer 2b is formed on both surfaces of the negative electrode current collector 2a, but may be formed only on one surface. The thickness of the negative electrode active material layer 24 is, for example, not less than 20 μm and not more than 50 μm.

  The negative electrode active material layer 2b contains a negative electrode active material. The negative electrode active material is a material that can reversibly store lithium ions. More specifically, examples of the negative electrode active material include graphite (graphite), non-graphitizable carbon (hard carbon), and pulverized products thereof.

  The lithium electrode 3 includes a lithium electrode current collector 3a and a lithium foil 3b. As the lithium electrode current collector 3a, a porous metal foil can be used. Examples of the material of the lithium electrode current collector 3a include copper and stainless steel. The thickness of the lithium electrode current collector 3a is, for example, not less than 10 μm and not more than 200 μm.

  The lithium foil 3b is, for example, pressure bonded to one surface of the lithium electrode current collector 3a. The material of the lithium foil 3b is lithium. The lithium foil 3b can function as a lithium ion supply source. That is, when the lithium electrode current collector 3a and the negative electrode current collector 2a are connected via the negative electrode lead 7 and short-circuited, the lithium foil 3b can be dissolved in the electrolytic solution and become lithium ions. Then, the lithium ions are electrochemically doped into the negative electrode active material layer 2b (also referred to as “pre-dope”) via the electrolytic solution. As a result, the potential of the negative electrode 2 can be lowered. The thickness of the lithium foil 3b is, for example, 50 μm or more and 300 μm or less.

  Note that the lithium foil 3b is completely dissolved in the electrolytic solution by pre-doping, for example, but in the illustrated example, the electrolytic solution is omitted for convenience and the lithium foil 3b before being dissolved in the electrolytic solution is illustrated. .

As the electrolytic solution, an aprotic organic solvent electrolytic solution containing lithium salt as an electrolyte is used. Examples of the aprotic organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolane, methylene chloride, sulfolane and the like. These solvents may be used alone or in combination of two or more. Examples of the lithium salt include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li (C ₂ F ₅ SO ₂ ) ₂ N, and the like.

  The electricity storage device 100 according to the present embodiment has, for example, the following characteristics.

According to the electricity storage device 100, the heat insulating member 20 is provided between the adjacent electricity storage cells 10. Thereby, heat transfer between the plurality of stacked power storage cells 10 can be suppressed. Therefore, it is possible to suppress the temperature rise of the storage cells arranged in the center of the stacked storage cells due to the heat generated by the adjacent storage cells, and the temperature difference between the storage cells 10 can be reduced. Can be made uniform. As a result, the voltage difference between the storage cells 10 can be reduced. Therefore, the electricity storage device 100 can have high reliability.

  For example, a laminate film containing aluminum (aluminum laminate film) is used as the outer package of the storage cell. In particular, the aluminum laminate film has high heat dissipation and heat transfer is likely to occur between the storage cells. According to the electricity storage device 100, even when such an aluminum laminate film is used as the exterior body 12, heat transfer between the electricity storage cells 10 can be suppressed by the heat insulating member 20.

  According to the electricity storage device 100, the electricity storage cells 10 are physically separated by the heat insulating member 20. Therefore, even if the temperature of one power storage cell 10 rises due to overcharging and a safety valve (not shown) is activated and the electrolyte in the power storage cell 10 is ejected, the power storage cell 10 from which the electrolyte is ejected The influence on other power storage cells 10 can be reduced. The storage cell from which the electrolytic solution is ejected becomes very high temperature (about 150 ° C.). For example, in a form in which the storage cells are in close contact with each other, the temperature of the storage cell that has become high temperature and the temperature of the adjacent storage cell by the electrolytic solution May increase and the storage cells may be destroyed in a chain. Such a problem can be avoided in the electricity storage device 100 according to the present embodiment. Moreover, according to the electrical storage device 100, since the temperature rise of the electrical storage cell 10 arrange | positioned in the center part can be suppressed, even if a safety valve operate | moves and electrolyte solution ejects, it can reduce ejection amount. And the temperature of the electrolyte can be lowered. Therefore, for example, a member for absorbing the electrolytic solution is not necessary, and the size can be reduced accordingly.

  In addition, it is assumed that heat insulation between the storage cells is achieved by increasing the distance between adjacent storage cells without providing the heat insulating member. However, in such a form, since the distance between the storage cells is increased, it is difficult to reduce the size of the storage device, and further, the earthquake resistance against external force is reduced. In the electricity storage device 100 according to this embodiment, the heat insulating member 20 can reduce the size and improve the earthquake resistance. That is, the heat insulating member 20 can also have a function as a buffer material.

2. Modification 2.1. First Modification Next, an electricity storage device 200 according to a first modification of the present embodiment will be described with reference to the drawings. FIG. 5 is a perspective view schematically showing an electricity storage device 200 according to a first modification of the present embodiment. FIG. 6 is a cross-sectional view schematically showing the electricity storage device 200 according to the first modification of the present embodiment, and is a cross-sectional view taken along the line VI-VI in FIG. In FIG. 5, for convenience, the outer member 30 is shown in a perspective view, and the exterior body 12 is further simplified. In FIG. 5, two power storage cells 10 are illustrated for convenience. In FIG. 6, for convenience, the outer member 30, the positive electrode, the negative electrode, and the like housed in the exterior body 12 are omitted.

  Hereinafter, in the electricity storage device 200 according to the first modification of the present embodiment, members having the same functions as those of the constituent members of the electricity storage device 100 according to the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

  As shown in FIGS. 5 and 6, the electricity storage device 200 includes a heat radiating plate 40 and a heat sink 50.

The heat sink 40 is provided between the electricity storage cell 10 and the heat insulating member 20. In the example shown in FIG. 6, the heat radiating plate 40 is further provided outside the storage cell 10 disposed at the end. Therefore, each of the plurality of power storage cells 10 is provided between the heat radiating plate 40 and the heat insulating member 20.

  The heat radiating plate 40 is bonded to the exterior body 12 of the storage cell 10 with, for example, an adhesive. As the adhesive, for example, an acrylic heat conductive sheet having high tackiness and heat transfer rate and low heat resistance can be used. Although the joining method between the heat sink 40 and the heat insulation member 20 is not specifically limited, You may adhere | attach by said acrylic heat conductive sheet.

  The shape of the heat sink 40 is a plate shape, and the thickness thereof is, for example, 0.2 mm or more and 20 mm or less. As the heat radiating plate 40, a material having high thermal conductivity can be used. Specifically, the material of the heat sink 40 includes aluminum and copper.

  The heat sink 50 is joined to the plurality of heat sinks 40. In the example shown in FIG. 6, the heat sink 50 is joined to all the heat sinks 40. Thereby, the several heat sink 40 can be thermally connected. Therefore, the entire power storage device 200 can be cooled while suppressing, for example, deterioration of only one power storage cell due to heat. The heat generated in the storage cell 10 is transmitted by the heat radiating plate 40 in a direction orthogonal to the stacking direction of the storage cells 10 and can be radiated from the heat sink 50.

  The joining of the heat sink 50 and the heat radiating plate 40 is not particularly limited. For example, a plurality of holes (not shown) are provided in the heat sink 50 and the heat radiating plate 40 in advance, and the holes of the heat sink 50 and the holes of the heat radiating plate 40 are formed. After arranging both so that it may overlap, it can carry out by press-fitting a knock pin (not shown) whose outer diameter is larger than the hole diameter (diameter). Since the knock pin is inserted into the hole while being plastically deformed, there is no gap between the knock pin and the hole, and the thermal resistance between the heat sink 50 and the heat radiating plate 40 can be reduced. Thereby, the heat transmitted from the heat sink 40 can be efficiently radiated from the heat sink 50. Further, the thermal resistance may be reduced by applying silicon grease between the heat sink 50 and the heat radiating plate 40.

  The heat sink 50 can have a protrusion 52. Thereby, the surface area of the heat sink 50 can be increased, and heat dissipation can be improved. As the heat sink 50, a material having high thermal conductivity can be used. Specifically, the material of the heat sink 50 includes aluminum and copper.

  Although not shown, a plurality of heat sinks 50 may be provided. Even in such a form, it is desirable to arrange the heat sink 50 so that each of the plurality of heat sinks 50 is joined to all the heat sinks 40 in consideration of temperature uniformity in the plurality of power storage cells 10. Although not shown, the heat sink 50 may be accommodated in the outer member 30.

  According to the electricity storage device 200, by providing the heat radiating plate 40 and the heat sink 50, for example, heat dissipation can be improved as compared with the electricity storage device 100. Furthermore, the heat sink 50 can thermally couple the plurality of heat sinks 40. Therefore, the entire power storage device 200 can be cooled while suppressing, for example, deterioration of only one power storage cell due to heat.

2.2. Second Modification Example Next, an electricity storage device 300 according to a second modification example of the present embodiment will be described with reference to the drawings. FIG. 7 is a perspective view schematically showing an electricity storage device 300 according to the second modification of the present embodiment. FIG. 8 is a cross-sectional view schematically showing an electricity storage device 300 according to a second modification of the present embodiment, and is a cross-sectional view taken along line VIII-VIII in FIG. In FIG. 7, for convenience, the outer member 30 is shown in a transparent manner, and the exterior body 12 is further simplified. Further, in FIG. 7, for convenience, two storage cells 10 are illustrated. In FIG. 8, for convenience, the outer member 30, the positive electrode, the negative electrode, and the like housed in the exterior body 12 are omitted.

  Hereinafter, in the electricity storage device 300 according to the second modification of the present embodiment, members having the same functions as those of the components of the electricity storage device 200 according to the first modification of the embodiment are denoted by the same reference numerals, Detailed description is omitted.

  In the example of the electricity storage device 200, as shown in FIGS. 5 and 6, each of the plurality of electricity storage cells 10 is sandwiched between the heat insulating member 20 and the heat radiating plate 40. On the other hand, in the electricity storage device 300, as shown in FIGS. 7 and 8, each of the plurality of electricity storage cells 10 is provided between two heat radiating plates 40. The heat insulating member 20 is also provided between the two heat sinks 40.

  According to the electricity storage device 300, for example, compared to the electricity storage device 200, the contact area between the electricity storage cell 10 and the heat sink 40 can be increased. Therefore, the heat dissipation can be further improved and the temperature rise can be suppressed.

2.3. Third Modification Example Next, an electricity storage device 400 according to a third modification example of the present embodiment will be described with reference to the drawings. FIG. 9 is a perspective view schematically showing an electricity storage device 400 according to a third modification of the present embodiment. In FIG. 9, for convenience, the outer member 30 is shown in a transparent manner, and the exterior body 12 is further simplified. In FIG. 9, two power storage cells 10 are illustrated for convenience.

  Hereinafter, in the electricity storage device 400 according to the third modification of the present embodiment, members having the same functions as those of the components of the electricity storage device 300 according to the second modification of the present embodiment are denoted by the same reference numerals, and Detailed description is omitted.

  The power storage device 400 includes a cooling fan 60 as shown in FIG. The position of the cooling fan 60 is not particularly limited, but is connected to the heat sink 50, for example. Thereby, the cooling fan 60 can blow air to the entire protrusion 52 of the heat sink 50. As a result, the heat sink 50 can radiate heat efficiently.

3. Examples Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited at all by the following examples.

3.1. Configuration of Power Storage Device The power storage devices according to Example 1, Example 2, and Comparative Example 1 were prepared as follows.

As Example 1, the electricity storage device 300 shown in FIGS. 7 to 8 was used. That is, six power storage cells 10 connected in series were stacked, and the heat insulating member 20 (“PE light” manufactured by INOAC) was disposed between the power storage cells 10. Further, a heat radiating plate 40 (aluminum plate having a thickness of 0.5 mm) was disposed so as to sandwich the storage cell 10. Bonding between the storage cell 10 and the heat radiating plate 40 and bonding between the heat radiating plate 40 and the heat insulating member 20 were performed using an adhesive (“thermal conductive sheet” manufactured by 3M). And after enclosing the electrical storage cell 10, the heat insulation member 20, and the heat sink 40 with the outer member 30 (Teraoka Seisakusho "polyester film tape"), the exterior member 3 was inserted | pinched with the aluminum plate (thickness 2mm) which is not shown in figure. . Furthermore, a heat sink 50 (“heat sink” manufactured by ABL) was joined to the heat radiating plate 40. Joining of the heat sink 40 and the heat sink 50 was performed using a knock pin (“Mock pin” manufactured by MISUMI).

As the electricity storage cell 10, a lithium ion capacitor in which 10 positive electrodes and 11 negative electrodes were alternately laminated via a separator and a laminate of the positive electrode and the negative electrode was sandwiched between lithium electrodes was used. An aluminum material was used as the material of the positive electrode current collector, and activated carbon was used as the material of the positive electrode active material. A copper material was used as the material of the negative electrode current collector, and hard carbon was used as the material of the negative electrode active material. A copper material was used as the material of the lithium electrode current collector. As an electrolytic solution, a propylene carbonate solvent containing a lithium salt of 1M-LiPF ₆ was used. As the exterior body 12, an aluminum laminate film was used.

  As Example 2, an electricity storage device 400 shown in FIG. 9 was used. That is, the cooling fan 60 was connected to the heat sink 50 of Example 1 to obtain Example 2.

  As Comparative Example 1, an electricity storage device 1000 shown in FIG. 10 was used. That is, in Example 1, the configuration in which the heat insulating member 20 and the heat sink 50 were not provided and the heat radiating plate 40 between the storage cells 10 was made one was referred to as Comparative Example 1. 10 is a cross-sectional view schematically showing the electricity storage device 1000 of Comparative Example 1. The electricity storage cell 1010 and the heat dissipation plate 1040 in FIG. 10 correspond to the energy storage cell 10 and the heat dissipation plate 40, respectively.

3.2. Charge / Discharge Test For Examples 1 and 2 and Comparative Example 1, constant current charge / discharge was repeated between 22.8 V and 13.2 V at 50 A, and the temperature of each of the six storage cells was investigated.

  FIGS. 11 to 13 are graphs showing temperature characteristics during charging and discharging, FIG. 11 shows the results of Example 1, FIG. 12 shows the results of Example 2, and FIG. The result of the comparative example 1 is shown.

  In FIG. 11 to FIG. 13, the six storage cells stacked are named “cell 1”, “cell 2”,..., “Cell 6” in order from the end. That is, “cell 1” and “cell 6” are storage cells located at the ends of the six stacked storage cells. This also applies to FIGS. 14 and 15 described later.

  11 to 13, “inter-cell temperature difference” is obtained by subtracting the temperature of the storage cell having the minimum temperature from the temperature of the storage cell having the maximum temperature.

  As shown in FIGS. 11 to 13, Examples 1 and 2 had a smaller temperature difference between the storage cells than Comparative Example 1. Further, in Examples 1 and 2, the temperature of the storage cell itself was lower than that in Comparative Example 1.

  From the above, it was found that the temperature difference between the storage cells can be reduced by providing a heat insulating member between the storage cells. Furthermore, it was found that the temperature of the storage cell can be reduced by providing a heat sink.

3.3. Overcharge test For Example 1 and Comparative Example 1, overcharge was performed, the voltage of each of the six energy storage cells, the voltage of the entire energy storage device, the charging current, and the energy storage cells (cells 1 and 6) arranged at the ends. The temperature was investigated. The overcharge was performed at a constant current and a constant voltage of 50 A and 30 V.

14 and 15 are graphs showing voltage, current, and temperature during overdischarge.
4 shows the result of Example 1, and FIG. 15 shows the result of Comparative Example 1.

  In Example 1, as shown in FIG. 14, even when overcharging was performed for 3 hours, it was not broken and almost no increase in temperature could be confirmed. On the other hand, as shown in FIG. 15, in Comparative Example 1, the cell was broken in about 25 minutes, and the temperature rose rapidly.

  From the above, it was found that Example 1 had higher reliability during overcharging than Comparative Example 1.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the present invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same purpose. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

1 positive electrode, 1a positive electrode current collector, 1b positive electrode active material layer, 2 negative electrode, 2a negative electrode current collector,
2b negative electrode active material layer, 3 lithium electrode, 3a lithium electrode current collector, 3b lithium foil,
4 separator, 5 electrode laminate, 6 positive electrode lead, 7 negative electrode lead, 10 electricity storage cell, 12 outer package, 12a first laminate film, 12b second laminate film,
13 1st flat surface, 14 2nd flat surface, 16 positive electrode terminal, 17 wiring, 18 negative electrode terminal, 20 heat insulation member, 30 outer member, 40 heat sink, 50 heat sink, 52 protrusion, 60 cooling fan, 100-400 device

Claims (10)

A power storage cell having a positive electrode, a negative electrode, and an exterior body in which an electrolytic solution is housed, is a power storage device in which a plurality of layers are stacked,
An electricity storage device including a heat insulating member provided between the adjacent energy storage cells. In claim 1,
The said exterior body is an electrical storage device which is a laminate film. In claim 1 or 2,
The electricity storage device in which the electricity storage cell and the heat insulating member are alternately stacked. In any one of Claims 1 thru | or 3,
An electricity storage device further comprising a heat sink disposed between the electricity storage cell and the heat insulating member. In claim 4,
An electricity storage device further comprising a heat sink connected to the heat sink. In claim 5,
An electricity storage device further comprising a cooling unit for cooling the heat sink. In any one of Claims 1 thru | or 6,
The heat insulating member is a foam heat insulating material having a thermal conductivity of 0.05 W / mK to 0.08 W / mK, or a fiber heat insulating material having a heat conductivity of 0.02 W / mK to 0.05 W / mK. There is an electricity storage device. In any one of Claims 1 thru | or 7,
The power storage device, wherein the heat insulating member is made of polyurethane or glass wool. In any one of Claims 1 thru | or 8,
The storage cell is
A positive electrode terminal electrically connected to the positive electrode;
A negative electrode terminal electrically connected to the negative electrode;
Have
The power storage device, wherein the positive electrode terminal and the negative electrode terminal are provided so as to protrude in opposite directions from the exterior body. In any one of Claims 1 thru | or 9,
The exterior body is
A first flat surface;
A second flat surface facing away from the first flat surface and having a smaller area than the first flat surface;
Have
The adjacent electricity storage cells are stacked such that the first flat surfaces are opposed to each other or the second flat surfaces are opposed to each other via the heat insulating member.

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