WO2016035308A1

WO2016035308A1 - Power storage device

Info

Publication number: WO2016035308A1
Application number: PCT/JP2015/004387
Authority: WO
Inventors: 増田　英樹; 北野　真也
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2014-09-03
Filing date: 2015-08-28
Publication date: 2016-03-10
Also published as: JPWO2016035308A1

Abstract

The purpose of the present invention is to provide a power storage device with which damage to a lithium ion supply layer is suppressed when a storage element 3 is housed in an outer casing. A power storage device 1 is provided with an outer casing 2, a storage element 3 that comprises a negative electrode 32 and is housed in the outer casing 2, and a lithium ion supply layer 42 for supplying lithium ions to the negative electrode 32 to be housed in the outer casing 2. The lithium ion supply layer 42 is formed on an inside surface 41 at a bottom wall 40 of the outer casing 2. Damage to the lithium ion feed layer 42 can thereby be suppressed when the storage element 3 is housed in the outer casing 2.

Description

Electricity storage element

The technique disclosed in this specification relates to a power storage element including a negative electrode housed in an exterior body.

Conventionally, a battery in which a power generation element is housed in a battery case is known (Japanese Patent Laid-Open No. 2008-192540). In this battery, a lithium ion supplier made of a lithium compound capable of releasing lithium ions is disposed on the inner surface of the battery case.

JP 2008-192540 A

However, according to the above configuration, when the power generation element is accommodated in the battery case, the lithium ion supplier disposed on the inner surface of the battery case and the power generation element may come into contact with each other, and the lithium ion supply body may be damaged. There is.

This specification discloses a technology related to a power storage element in which the lithium ion supply layer is prevented from being damaged when the power storage element is accommodated in the exterior body.

A power storage element described in this specification includes an exterior body, a power storage element including a negative electrode housed in the exterior body, and a lithium ion supply layer that supplies lithium ions to the negative electrode housed in the exterior body. The lithium ion supply layer is formed on the bottom surface of the outer package.

According to the technology disclosed in this specification, it is possible to suppress damage to the lithium ion supply layer when the power storage element is accommodated in the exterior body.

The perspective view which shows the electrical storage element which concerns on Embodiment 1 of this invention. The exploded perspective view which shows the electrical storage element of this invention Sectional drawing which shows the electrical storage element which concerns on Embodiment 1 of this invention Sectional drawing which shows the electrical storage element which concerns on Embodiment 2 of this invention. Sectional drawing which shows the electrical storage element which concerns on Embodiment 3 of this invention. Sectional drawing which shows the electrical storage element which concerns on Embodiment 4 of this invention. Schematic which shows the electrical storage apparatus provided with the electrical storage element of this invention Schematic which shows the motor vehicle provided with the electrical storage apparatus provided with the electrical storage element of this invention.

(Outline of this embodiment)
A power storage element described in this specification includes an exterior body, a power storage element including a negative electrode housed in the exterior body, and a lithium ion supply layer that supplies lithium ions to the negative electrode housed in the exterior body. The lithium ion supply layer is formed on the bottom surface of the outer package.

When the power storage element is accommodated in the exterior body, the power storage element may come into contact with the inner surface of the side wall of the exterior body. At this time, for example, if a lithium ion supply layer is formed on the inner surface of the side wall of the exterior body, the power storage element may come into contact with the lithium ion supply body and the lithium ion supply layer may be damaged.

According to the electricity storage device described in the present specification, when the electricity storage element is accommodated in the exterior body, it is possible to suppress the interference between the lithium ion supply layer and the electricity storage element, so that the lithium ion supply layer is damaged. Can be suppressed.

The power storage element is a wound power storage element in which the negative electrode, the positive electrode, and a separator are wound, and the wound power storage element has a substantially oval cross-sectional shape in a direction perpendicular to the winding axis. The lithium ion supply layer may be formed between a portion having a curved shape of the wound power storage element and a bottom surface of the exterior body.

In the outer surface of the wound power storage element in which the cross-sectional shape in the direction orthogonal to the winding axis forms an oval shape, the side surface intersecting the major axis direction of the cross-sectional shape has a relatively large curvature. For this reason, a relatively large space is formed between the side surface of the wound power storage element that intersects the long axis direction of the cross-sectional shape and the inner surface of the case having a rectangular parallelepiped shape. Space efficiency can be improved by arranging the lithium ion supply layer in this relatively large space.

The lithium ion supply layer may be formed by applying a mixture containing a lithium ion supplier to the bottom surface of the exterior body.

According to the above configuration, the lithium ion supply body can be arranged in the case by a simple method of applying a mixture containing the lithium ion supply body to the inner surface of the exterior body.

The surface of the lithium ion supply layer may be covered with an insulating sheet through which lithium ions pass.

According to the above configuration, the lithium ion supply layer can be prevented from being detached from the bottom surface in the exterior body by the sheet.

The area of the inner surface of the outer package in which the lithium ion supply layer is formed may be rougher than the area of the inner surface of the outer package in which the lithium ion supply layer is not formed.

According to the above configuration, since the region of the inner surface of the exterior body on which the lithium ion supply layer is formed is rough, the lithium ion supply layer can be made difficult to fall off from the inner surface of the exterior body.

A resistance coating may be formed on the inner surface of the outer package in which the lithium ion supply layer is formed.

According to the above configuration, even when power storage elements having different potentials of the exterior body are in contact with each other, it is possible to prevent the exterior bodies of the power storage elements from being short-circuited due to the presence of the resistance film.

A plurality of the power storage elements may be used to form a power storage device.

The power storage device may be used as an automobile.

<Embodiment 1>
A power storage device 1 according to Embodiment 1 will be described with reference to FIGS. In the following description, in FIG. 1, the lower right side of the sheet with the symbol F is the front side of the electricity storage element 1, the upper right side of the page with the symbol R is the right side of the electricity storage element 1, and the symbol U is attached. The upper side of the drawing is the upper side of the storage element 1.

(Storage element 1)
1 is a rechargeable secondary battery, more specifically a nonaqueous electrolyte secondary battery, and more specifically a lithium ion battery. The power storage element 1 is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and supplies power to a power source that operates with electric energy.

As shown in FIG. 2, the power storage element 1 has a configuration in which a power storage element 3 is accommodated in an exterior body 2 together with an electrolyte (not shown). The electrolyte may be an electrolytic solution or a solid electrolyte.

(Exterior body 2)
The exterior body 2 includes a case main body 4 and a lid body 5. The case main body 4 has a substantially rectangular parallelepiped shape as a whole, and an opening 4A is formed on one end surface side, that is, the upper end surface side. The case body 4 is made of a conductive material, and is made of metal such as aluminum or aluminum alloy.

The opening 4A has a rectangular shape in which the width dimension in the left-right direction is longer than the width dimension in the direction orthogonal to the left-right direction, that is, the front-rear direction. The case body 4 contains the electricity storage element 3 and is filled with an electrolyte. The power storage element 3 is accommodated inside the case body 4 in a posture in which the longitudinal direction of the case body 4 coincides with the longitudinal direction of the power storage element 3.

The lid 5 is provided with a positive electrode terminal 6, a negative electrode terminal 7, a positive electrode current collector 8, and a negative electrode current collector 9. The lid body 5 has a substantially rectangular shape as a whole, and has substantially the same shape as the opening 4A. The lid 5 is joined to the case body 4 so as to close the opening 4 </ b> A of the case body 4. The lid 5 is made of a conductive material, and is made of metal such as aluminum or aluminum alloy.

A positive electrode terminal 6 and a negative electrode terminal 7 are arranged on the outer surface, ie, the upper surface of the lid 5. Specifically, the positive electrode terminal 6 is disposed on one end side in the longitudinal direction of the lid 5, that is, the left side, and the negative electrode terminal 7 is disposed on the other end side in the longitudinal direction, that is, the right side.

Two positive electrode current collectors 8 extending downward from the lower surface of the lid 5 are disposed near the left end of the lid 5. Although not shown in detail, the upper end portion of the positive electrode current collector 8 is electrically connected to the positive electrode terminal 6.

The positive electrode current collector 8 has an elongated shape along the portion where the positive electrode current collector foil 33 is exposed in the electricity storage element 3 to be described later. The two positive electrode current collectors 8 are arranged so that their plate surfaces face each other. The positive electrode current collector 8 is made of a metal plate having a sufficient thickness so as to obtain a large current capacity, such as an aluminum alloy plate.

Two negative electrode current collectors 9 extending downward from the lower surface of the lid 5 are disposed at a position from the right end of the lid 5. Although not shown in detail, the upper end portion of the negative electrode current collector 9 is electrically connected to the negative electrode terminal 7.

The negative electrode current collector 9 has an elongated shape along the portion where the negative electrode current collector foil 34 is exposed in the electricity storage element 3 to be described later. The two negative electrode current collectors 9 are arranged so that their plate surfaces face each other. The negative electrode current collector 9 is made of a metal plate having a sufficient thickness so as to obtain a large current capacity, such as a copper alloy plate.

(Storage element 3)
The power storage element 3 is formed by, for example, winding a positive electrode 31 and a negative electrode 32 through a separator 37 with the long side of a polyethylene core having a substantially rectangular plate shape being the center of the winding axis. This is a winding type power storage element.

Thereby, the electrical storage element 3 corresponds to the core, and is long in the direction along the winding axis of the core, short in the direction perpendicular to the winding axis of the core, and perpendicular to the plate surface of the core. It is configured in a cylindrical shape wound in a short flat shape. The electricity storage element 3 has a shape in which the area of the region formed by the direction along the short side direction of the core and the direction along the long side direction of the core is larger than the areas of the other regions. And the electrical storage element 3 is accommodated in the case main body 4 by making the long side direction of a winding core into the left-right direction.

The cross-sectional shape of the electricity storage element 3 in the direction orthogonal to the winding axis is substantially oval. The substantially oval shape includes an oval shape and also includes a shape that can be regarded as an oval shape even if it is not an oval shape. Further, the substantially oval shape includes an elliptical shape.

(Positive electrode 31)
The positive electrode 31 is obtained by forming a positive electrode mixture layer on the surface of an aluminum foil having a strip shape in which the winding direction is the longitudinal direction. The positive electrode 31 has a portion where the positive electrode current collector foil 33 is exposed without forming the positive electrode mixture layer on one edge extending in the longitudinal direction. The positive electrode mixture layer includes a positive electrode active material, and may include a conductive additive, a binder, and the like in addition to the positive electrode active material.

The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions, and may be an inorganic compound or an organic compound. For example, as an inorganic compound, transition metal oxides such as manganese dioxide (MnO ₂ ), iron oxide, copper oxide, nickel oxide, vanadium oxide (for example, V ₂ O ₅ ); spinel represented by LiMn ₂ O ₄ or the like Transition metal oxides having a spinel crystal structure typified by spinel type lithium nickel manganese oxide and the like represented by type lithium manganese oxide, LiNi _1.5 Mn _0.5 O _{4 and the} like; LiCoO ₂ , LiNiO ₂ LiMeO ₂ type having an α-NaFeO ₂ structure represented by LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li _1.1 Co _2/3 Ni _1/6 Mn _1/6 O _2, etc. Me is a transition metal) lithium transition metal composite _{_{_{_{oxide; Li x FePO 4, Li x}}}} Fe 1-y Mn y PO 4, Olympoi such Li x CoPO ₄ Lithium phosphorus oxides having the structure. Examples of organic compounds include conductive polymer materials such as polyaniline and polypyrrole; disulfide polymer materials; sulfur (S); iron sulfate (Fe ₂ (SO ₄ ))
₃ ) and the like.

As the positive electrode active material, a so-called lithium-excess type lithium transition metal composite oxide that can be expressed as Li _{1 + α} Me _1-α O ₂ (α> 0) can also be used. These positive electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of conductive assistants include carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) powder, metal fiber, conductive ceramic material, etc. Materials. These conductive assistants may be used alone or in combination of two or more.

The type of the binder is not particularly limited as long as it is a material that is stable with respect to a solvent and an electrolytic solution used at the time of electrode production and is stable with respect to an oxidation-reduction reaction at the time of charge and discharge. Examples of the binder include thermoplastic resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, and polypropylene; ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, and styrene butadiene rubber (SBR). ), Polymers having rubber elasticity such as fluororubber. These binders may be used individually by 1 type, and may be used in combination of 2 or more type.

Further, if necessary, the positive electrode mixture may contain a viscosity modifier and the like. As the viscosity modifier, any compound such as carboxymethylcellulose (CMC) and N-methylpyrrolidone (NMP) can be appropriately selected as necessary.

The positive electrode 31 is overlapped so that the portion where the positive electrode current collector foil 33 is exposed is arranged on one end side, that is, on the positive electrode 31 side (left side) from the separator 37 and the positive electrode mixture layer. Moreover, the negative electrode 32 is overlaid so that the portion where the negative electrode current collector foil 34 is exposed is arranged on the other end side of the separator 37 and the negative electrode mixture layer, that is, on the negative electrode 32 side (right side).

Thereby, only the part which the positive electrode current collector foil 33 exposes is laminated | stacked and provided in the one end side of the electrical storage element 3, ie, the positive electrode 31 side (left side), and the other end side, ie, the negative electrode 32 side (right side). Only the portion where the negative electrode current collector foil 34 is exposed is laminated.

(Negative electrode 32)
The negative electrode 32 is obtained by forming a negative electrode mixture layer on the surface of a copper foil having a strip shape in which the winding direction is the longitudinal direction. The negative electrode 32 has a portion where the negative electrode current collector foil 34 is exposed without forming the negative electrode mixture layer at one edge extending in the longitudinal direction. The negative electrode mixture layer includes a negative electrode active material, and may include a conductive additive and a binder in addition to the negative electrode active material.

As the conductive additive, binder, viscosity modifier and the like used for the negative electrode 32, the same ones as those used for the positive electrode 31 can be appropriately selected and used.

The negative electrode active material is not particularly limited as long as it can reversibly store and release lithium ions. Specific examples of the negative electrode active material include amorphous carbon such as non-graphitizable carbon (hard carbon) and graphitizable carbon (soft carbon); graphite; Al, Si, Pb, Sn, Zn, Cd, etc. Alloys of these metals and lithium; tungsten oxide; molybdenum oxide; iron sulfide; titanium sulfide; lithium titanate and the like. These negative electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type. Among these negative electrode active materials, amorphous carbon and graphite are preferable.

(Separator 37)
The separator 37 is not particularly limited as long as it has insulating properties. As the separator 37, for example, a polyolefin microporous film; a synthetic resin woven or non-woven fabric; a natural fiber, glass fiber, or ceramic fiber woven or non-woven fabric; paper or the like can be used. The polyolefin microporous membrane can be selected from polyethylene, polypropylene, and composite membranes thereof. The synthetic resin fiber can be selected from polyolefins such as polyacrylonitrile (PAN), polyamide (PA), polyester, polyethylene terephthalate (PET), polypropylene (PP) or polyethylene (PE), and mixtures thereof.

(Electrolytes)
As the electrolyte, an electrolytic solution or a solid electrolyte can be used. As the electrolytic solution, a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent can be used. In the exterior body 2, the electrolyte solution is impregnated in the positive electrode mixture layer, the negative electrode mixture layer, and the separator 37. The electrolytic solution is not limited, and those generally proposed for use in lithium ion batteries and the like can be used. Nonaqueous solvents include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate and other cyclic carbonates; γ-butyrolactone, γ-valerolactone and other cyclic esters; dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and other chains Examples of the carbonates include chain esters such as methyl formate, methyl acetate, and methyl butyrate alone or a mixture of two or more thereof, but are not limited thereto. In addition, you may add a well-known additive to electrolyte solution.

Examples of the electrolyte salt include inorganic ion salts containing one kind of lithium (Li), sodium (Na), or potassium (K) such as LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , and LiSCN; LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F _And organic ion salts such as ₅ SO ₂ ) ₃ and (CH ₃ ) ₄ NBF ₄ . These ionic compounds can be used alone or in admixture of two or more. The content of the supporting salt in the electrolyte is not particularly limited, and may be set as appropriate according to the type of the supporting salt used, the solvent, etc., for example, 0.1 to 5.0 mol / L, preferably 0. 8 to 2.0 mol / L can be mentioned.

Furthermore, by mixing and using a lithium salt having a perfluoroalkyl group such as LiN (C ₂ F ₅ SO ₂ ) ₂ , it is possible to reduce the viscosity of the electrolyte and to suppress self-discharge of the storage element. It is possible and preferable.

Also, a room temperature molten salt or ionic liquid may be used as the electrolytic solution.

When a solid electrolyte is used as the electrolyte, a polymer solid electrolyte can be used as the solid electrolyte, and a porous polymer solid electrolyte membrane can be used as the polymer solid electrolyte. The polymer solid electrolyte can further contain an electrolytic solution. Further, when a gel polymer solid electrolyte is used as the electrolyte, the electrolyte solution constituting the gel may be different from the electrolyte solution contained in the pores.

(Connection structure between current collector and power storage element 3)
The positive electrode current collector 8 and the positive electrode current collector foil 33 are connected by ultrasonic welding while being sandwiched between the clips 35. The negative electrode current collector 9 and the negative electrode current collector foil 34 are connected by ultrasonic welding while being sandwiched between the clips 36.

The clip 35 is made of a material having a resistance value substantially equal to the material of the positive electrode current collector 8 and the positive electrode current collector foil 33 to be connected. In the present embodiment, the clip 35 on the positive electrode 31 side is made of, for example, an aluminum alloy.

The clip 36 is made of a material having a resistance value substantially equal to the material of the negative electrode current collector 9 and the negative electrode current collector foil 34 to be connected. In the present embodiment, the clip 36 on the negative electrode 32 side is made of, for example, a copper alloy.

(Lithium ion supply layer 42)
As shown in FIGS. 2 and 3, the case body 4 of the exterior body 2 includes a bottom wall 40 at a position opposite to the opening 4 </ b> A. From the four side edges of the bottom wall 40, side walls 50 are formed to rise upward.

In addition, the bottom wall 40 does not mean a wall arranged on the lower side with respect to gravity, but means a wall arranged on the side opposite to the opening 4A of the case body 4. For this reason, when the electrical storage element 1 is used, for example, the bottom wall 40 may be in a posture positioned on the upper side with respect to gravity. The electrical storage element 1 can be arrange | positioned with arbitrary attitude | positions as needed.

3, a lithium ion supply layer 42 that supplies lithium ions to the negative electrode 32 is formed on the inner surface 41 (an example of the bottom surface) of the bottom wall 40.

The lithium ion supply layer 42 includes a lithium ion supplier that releases lithium ions when a positive voltage is applied, and may include a conductive aid, a binder, and the like in addition to the lithium ion supplier.

The lithium ion supplier is not particularly limited as long as it can occlude and release lithium ions, and may be, for example, an inorganic compound. Moreover, you may use metallic lithium as a lithium ion supply body. As an inorganic compound, spinel type lithium manganese oxide represented by LiMn ₂ O ₄ or the like, spinel type represented by spinel type lithium nickel manganese oxide or the like represented by LiNi _1.5 Mn _0.5 O ₄ or the like Lithium transition metal oxide having a crystal structure; LiCoO ₂ , LiNiO ₂ , LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li _1.1 Co _2/3 Ni _1/6 Mn _1/6 O _2, etc. LiMeO ₂ type (Me is a transition metal) lithium transition metal composite oxide having an alpha-NaFeO ₂ structure represented _{_{_{_{by; Li x FePO 4, Li x}}}} Fe 1-y Mn y PO 4, olivine such as Li x CoPO ₄ Examples thereof include a lithium phosphorus oxide having a structure.

In addition, a so-called lithium-excess type lithium transition metal composite oxide that can be expressed as Li _{1 + α} Me _1-α O ₂ (α> 0) can also be used as the lithium ion supplier. Here, the Li / Me ratio is preferably 1.25 to 1.6. If the Li / Me ratio is β, β = (1 + α) / (1−α). For example, when Li / Me is 1.5, α = 0.2. The ratio of elements such as Co, Ni and Mn constituting the transition metal element constituting the lithium transition metal composite oxide can be arbitrarily selected according to the required characteristics, but the discharge capacity increases. The molar ratio Co / Me of the transition metal element Me is preferably 0.02 to 0.23, more preferably 0.04 to 0.21, and even more preferably 0.06 to 0.17. Further, since the discharge capacity is increased, the molar ratio Mn / Me of the transition metal element Me is preferably 0.63 to 0.72, and more preferably 0.65 to 0.71.

These lithium ion suppliers may be used alone or in combination of two or more. In addition, the lithium ion supplier includes LiMeO ₂ type lithium transition metal composite oxide (Me is a transition metal), vanadium oxide (V ₂ O ₅ ), and lithium-excess type lithium transition metal composite oxide (Li _{1 + α} ) containing nickel. It is preferable to include one or more compounds selected from the group consisting of Me _1-α O ₂ (α> 0), Me is a transition metal).

As the lithium ion supplier, the same material as the positive electrode active material contained in the positive electrode mixture layer may be used, or a different material may be used.

The discharge capacity of the lithium ion supply layer 42 is preferably 1% or more and 20% or less, and more preferably 3% or more and 12% or less with respect to the discharge capacity of the positive electrode 31.

The type of conductive aid contained in the lithium ion supply layer 42 is not particularly limited. Examples of conductive assistants include carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) powder, metal fiber, conductive ceramic material, etc. Materials. These conductive assistants may be used alone or in combination of two or more. The conductive auxiliary agent used for the lithium ion supply layer 42 and the conductive auxiliary agent used for the positive electrode 31 may be the same substance or different substances.

The kind of the binder contained in the lithium ion supply layer 42 is not particularly limited as long as it is stable with respect to a solvent and an electrolytic solution used when manufacturing the electrode. Examples of the binder include thermoplastic resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, and polypropylene; ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, and styrene butadiene rubber (SBR). ), Polymers having rubber elasticity such as fluororubber. These binders may be used individually by 1 type, and may be used in combination of 2 or more type. The binder contained in the lithium ion supply layer 42 may be the same material as the binder contained in the positive electrode mixture layer, or may be a different material.

The composition of the lithium ion supply layer 42 is such that the lithium ion supplier is 50 parts by mass or more and 96 parts by mass or less, the conductive assistant is 2 parts by mass or more and 30 parts by mass or less, and the binder is 2 parts by mass or more and 30 parts by mass or less. It can be. In the composition of the lithium ion supply layer 42, if the conductive agent is 10 parts by mass or more and 30 parts by mass or less, the electric resistance of the lithium ion supply layer 42 is lowered even when the lithium ion supply layer 42 is formed thick. Can be preferred. In the composition of the lithium ion supply layer 42, if the binder is 10 parts by mass or more and 30 parts by mass or less, the lithium ion supply layer 42 may fall off and be damaged even when the lithium ion supply layer 42 is formed thick. Can be suppressed, which is preferable. The lithium ion supply layer 42 may contain components other than those described above.

As shown in FIG. 3, a lithium ion supply layer 42 is formed by applying a mixture containing a lithium ion supplier, a conductive additive, and a binder to the inner surface 41 of the bottom wall 40. . In the present embodiment, a lithium ion supply layer 42 is formed on substantially the entire bottom wall 40 in a cross section of the case body 4 in a direction perpendicular to the longitudinal direction of the case body 4.

The lithium ion supply layer 42 and the case body 4 are electrically connected. Further, since the case body 4 and the lid 5 are also electrically connected, the lithium ion supply layer 42 is also electrically connected to the lid 5.

The lithium ion supply layer 42 can be formed by applying a mixture containing a lithium ion supplier, a conductive additive, and a binder to the inner surface 41 of the bottom wall 40 of the case body 4 and drying the mixture. . Moreover, the lithium ion supply layer 42 can also be formed by applying a mixture and drying it, and further applying a mixture and drying it repeatedly, so-called overcoating. Further, the lithium ion supply layer 42 can be formed by applying a mixture to the inner surface 41 of the bottom wall 40 of the case body 4 and then sintering the mixture. Thus, the lithium ion supply layer 42 can be formed by an arbitrary method as necessary.

The introduction of lithium ions contained in the lithium ion supply layer 42 into the negative electrode 32 can be performed, for example, by applying a voltage between the exterior body 2 and the negative electrode terminal 7. The current flowing between the exterior body 2 and the negative electrode terminal 7 can be equal to or less than the current (A) having the same value as the capacity of the lithium ion supply layer 42, and the thickness of the lithium ion supply layer 42 is relatively large. In such a case, it is preferable that the current (A) has a smaller value. The voltage applied between the outer package 2 and the negative electrode terminal 7 varies depending on the type of the lithium ion supply body included in the lithium ion supply layer 42, but can be 3.5V to 4.2V.

(Manufacturing process of embodiment)
Then, an example of the manufacturing process of the electrical storage element 1 which concerns on this embodiment is demonstrated. In addition, the manufacturing process of the electrical storage element 1 is not limited to the following description.

The positive electrode 31 is manufactured as follows. A positive electrode active material (for example, lithium transition metal oxide), a binder (for example, polyvinylidene fluoride), and a conductive additive (for example, acetylene black) are mixed. A positive electrode mixture is prepared by appropriately adding N-methylpyrrolidone thereto to prepare a paste. This positive electrode mixture is applied to both surfaces of a positive electrode substrate made of an aluminum foil. This is dried, and the positive electrode 31 is produced by pressurizing with a roll press.

The negative electrode 32 is produced as follows. A negative electrode active material (for example, hard carbon) and a binder (for example, polyvinylidene fluoride) are mixed. N-methylpyrrolidone is appropriately added thereto to prepare a paste, thereby preparing a negative electrode mixture. This negative electrode mixture is applied to both surfaces of a negative electrode substrate made of copper foil. This is dried and the negative electrode 32 is produced by pressurizing with a roll press.

As the separator 37, for example, a polyolefin microporous film is used.

The winding type power storage element 3 is manufactured by winding the positive electrode 31 and the negative electrode 32 obtained as described above through the separator 37.

Using the metal plate material, the case body 4 having the opening 4A and the lid body 5 are created. A positive terminal 6 and a negative terminal 7 are attached to the lid 5. A positive electrode current collector 8 is connected to the positive electrode terminal 6, and a negative electrode current collector 9 is connected to the negative electrode terminal 7.

In a state where the positive electrode current collector foil 33 and the positive electrode current collector 8 are sandwiched between the clips 35, the clip 35 is ultrasonically welded to the positive electrode current collector foil 33 and the positive electrode current collector 8. Further, the clip 36 is ultrasonically welded to the negative electrode current collector foil 34 and the negative electrode current collector 9 in a state where the negative electrode current collector foil 34 and the negative electrode current collector 9 are sandwiched between the clips 36. Thereby, the electrical storage element 3 is connected to the lid 5.

The case body 4 is formed into a predetermined shape using a metal plate. A mixture containing a lithium ion supplier is applied to the inner surface 41 of the bottom wall 40 of the case body 4. By drying this, a lithium ion supply layer 42 is formed on the inner surface 41 of the bottom wall 4 of the case body 4.

Subsequently, the power storage element 3 connected to the lid 5 is inserted into the case body 4 from the opening 4 </ b> A of the case body 4. The hole edge of the opening 4A of the case body 4 and the side edge of the lid 5 are welded by a known method. An electrolyte is injected from an injection port (not shown) provided on the side wall 50 of the case body 4, and the injection port is sealed.

Then, a positive voltage is applied to the case body 4 and a negative voltage is applied to the negative electrode terminal 7, thereby releasing lithium ions from the lithium ion supply layer 42 and introducing lithium ions into the negative electrode 32. Thereby, the charge (precharge) for supplementing part or all of the irreversible capacity of the negative electrode 32 is completed for the power storage element 1.

(Operation and effect of the embodiment)
Then, the effect | action and effect of this embodiment are demonstrated. The power storage device according to this embodiment includes an exterior body, a power storage element 3 including a negative electrode 32 housed in the exterior body, and a lithium ion supply layer that supplies lithium ions to the negative electrode 32 housed in the exterior body, The lithium ion supply layer is formed on the bottom surface in the exterior body.

When the electricity storage element 3 is accommodated in the exterior body 2, the electricity storage element 3 may come into contact with the inner surface of the side wall of the exterior body 2. At this time, for example, if the lithium ion supply layer 42 is formed on the inner surface of the side wall of the exterior body 2, the power storage element 3 may come into contact with the lithium ion supply layer 42 and the lithium ion supply layer 42 may be damaged.

According to the electricity storage device 1 according to the present embodiment, the lithium ion supply layer 42 and the electricity storage element 3 can be prevented from interfering with each other when the electricity storage element 3 is accommodated in the exterior body 2. It is possible to prevent the supply layer 42 from being damaged.

The lithium ion supply layer 42 is formed by applying a mixture containing a lithium ion supply body to the inner surface 41 of the bottom wall 40 of the case body 4.

According to said structure, the lithium ion supply layer 42 can be formed in the exterior body 2 by the simple method of apply | coating the mixture containing a lithium ion supply body to the inner surface 41 of the bottom wall 40 of the case main body 4. FIG. it can.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to FIG. As shown in FIG. 4, the lithium ion supply layer 42 is formed between a portion having a curved shape of the power storage element 3 having a winding shape and the inner surface 41 of the bottom wall 40 of the case body 4. In addition, the part which has the curved-surface shape of the electrical storage element 3 means the side surface which cross | intersects the major axis direction (up-down direction in FIG. 4) of the cross-sectional shape of the outer surface of the electrical storage element 3 in the direction orthogonal to a winding axis. That is, the lithium ion supply layer 42 is formed at the front corner and the rear corner of the bottom wall 40 in the cross section of the case main body 4 in the direction orthogonal to the longitudinal direction of the case main body 4.

In the outer surface of the winding type power storage element 3 in which the cross-sectional shape in the direction orthogonal to the winding axis forms an oval shape, the side surface intersecting the long axis direction of the cross-sectional shape has a relatively large curvature. Therefore, a relatively large space 51 is formed between the side surface of the wound power storage element 3 that intersects the long axis direction of the cross-sectional shape and the inner surface of the case body 4 having a rectangular parallelepiped shape. .

According to the present embodiment, the lithium ion supply layer 42 is between the side surface of the winding-type electricity storage element 3 that intersects the major axis direction of the cross-sectional shape and the inner surface of the case body 4 having a rectangular parallelepiped shape. Since it is arranged in a relatively large space 51, space efficiency can be improved.

<Embodiment 3>
Next, Embodiment 3 will be described with reference to FIG. As shown in FIG. 5, a roughened region 60 in which the inner surface 41 of the bottom wall 40 is roughened is formed on the inner surface 41 of the bottom wall 40 of the case body 4 in the region where the lithium ion supply layer 42 is formed. ing.

The roughened region 60 is roughened from the inner surface of the side wall 50 of the case body 4 and the inner surface 41 of the bottom wall 40 than the region different from the region where the lithium ion supply layer 42 is formed. That is, the roughened region 60 is a region that is rougher than the region of the inner surface of the exterior body in which the lithium ion supply layer is not formed. The roughened region 60 can be formed by a known method such as embossing, brushing with a metal brush, sand blasting, laser irradiation, etching, or the like.

The surface of the lithium ion supply layer 42 is covered with a protective member 61 that allows lithium ions to pass therethrough. By being covered with this protective member 61, the lithium ion supply layer 42 is prevented from dropping from the inner surface 41 of the bottom wall 40 of the case body 4.

The protective member 61 may be an insulating sheet through which lithium ions pass. As the sheet, a polyolefin microporous film; a woven or non-woven fabric made of a synthetic resin; a natural fiber; a woven or non-woven fabric of glass fiber or ceramic fiber; paper or the like can be used. The polyolefin microporous membrane can be selected from polyethylene, polypropylene, and composite membranes thereof. The synthetic resin fiber can be selected from polyolefins such as polyacrylonitrile (PAN), polyamide (PA), polyester, polyethylene terephthalate (PET), polypropylene (PP) or polyethylene (PE), and mixtures thereof.

Further, the protection member 61 may be a metal member having a plurality of through holes, such as a wire mesh or a punching metal. As a metal member, arbitrary metals, such as copper, aluminum, and stainless steel, can be appropriately selected as necessary. As a metal member, you may use the same material as the metal which comprises the exterior body 4. FIG.

Further, the protective member 61 may be a member made of synthetic resin, which is formed in a net shape or a plate shape in which a plurality of through holes are formed.

The mixture containing the lithium ion supplier may be filled in the mesh or the through-hole formed in the protective member 61 made of metal or synthetic resin. Thereby, the amount of lithium ions introduced into the negative electrode 32 can be increased.

Since the configuration other than the above is substantially the same as that of the first embodiment, the same members are denoted by the same reference numerals, and redundant description is omitted.

According to this embodiment, the surface of the lithium ion supply layer 42 is covered with the protective member 61 that allows lithium ions to pass therethrough. By covering the lithium ion supply layer 42 with the protective member 61, it is possible to prevent the lithium ion supply layer 42 from dropping from the inner surface 41 of the bottom wall 40 of the case body 4.

Further, according to the present embodiment, the inner surface 41 of the bottom wall 40 of the case body 4 has a region where the lithium ion supply layer 42 is formed in a region different from the region where the lithium ion supply layer 42 is formed. A roughened roughened region 60 is formed.

With the above configuration, the lithium ion supply layer 42 is firmly held on the inner surface 41 of the bottom wall 40 of the case body 4. Thereby, it is possible to prevent the lithium ion supply layer 42 from being detached from the inner surface 41 of the bottom wall 40 of the case body 4.

<Embodiment 4>
Next, Embodiment 4 will be described with reference to FIG. As shown in FIG. 6, a resistance coating 62 is formed on the inner surface 41 of the bottom wall 40 of the case body 4 in the region where the lithium ion supply layer 42 is formed. The resistance film 62 has a higher electrical resistance than a region where the lithium ion supply layer 42 is not formed.

The resistance film 62 can be formed, for example, by oxidizing the inner surface 41 of the bottom wall 40 of the case body 4 to form an oxide film. The inner surface 41 of the bottom wall 40 of the case body 4 may be coated with a ceramic film. Further, a mixture containing a binder (for example, PVDF) and a conductive additive (for example, acetylene black) may be applied to the inner surface 41 of the bottom wall 40 of the case body 4.

In the electricity storage device 1 according to the present embodiment, after the charging step (precharge step) for introducing lithium ions contained in the lithium ion supply layer 42 into the negative electrode 32 is completed, the exterior body 4 is at a potential relative to the positive electrode 31. Have For this reason, the exterior bodies 4 of the plurality of power storage elements 1 that have completed the precharge process may have different potentials. When the power storage elements 1 having different potentials of the outer package 4 come into contact with each other, there is a concern that the outer packages 4 of the power storage element 1 are short-circuited and a short-circuit current flows.

In view of the above points, in the present embodiment, a resistance film 62 is formed on the inner surface 41 of the bottom wall 40 of the case body 4 in a region where the lithium ion supply layer 42 is formed. Has a larger electric resistance than the region where the lithium ion supply layer 42 is not formed.

With the above configuration, when the power storage elements 1 having different potentials of the outer package 4 are in contact with each other, the current flow from the lithium ion supply layer 42 to the case body 4 can be suppressed by the resistance coating 62. As a result, even when the exterior bodies 4 of the power storage element 1 are in contact with each other, it is possible to suppress a short-circuit current from flowing between the exterior bodies 4.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.

In the above embodiment, an example in which the electricity storage element 1 is a lithium ion battery which is a kind of nonaqueous electrolyte secondary battery has been described. However, the present invention is not limited thereto, and the storage element 1 may be another secondary battery such as a lead storage battery or a nickel hydride battery, or may be a primary battery. Moreover, a capacitor etc. may be sufficient.

In the above embodiment, the power storage element 3 of the power storage element 1 is the wound power storage element 3 formed in a flat shape by winding the positive electrode 31 and the negative electrode 32 via the separator 37, but is not limited thereto. For example, the power storage element 3 may be a stacked power storage element formed by stacking the positive electrode 31 and the negative electrode 32 with the separator 37 interposed therebetween.

The power storage element 1 according to the above embodiment is configured to include one power storage element 3, but is not limited thereto, and the power storage element 1 may be configured to include two or more power storage elements 3.

A power storage device can be configured by combining a plurality of power storage elements according to the above embodiment, and one embodiment thereof is shown in FIG. The power storage device 101 includes a plurality of power storage units 100. Each power storage unit 100 includes a plurality of power storage elements 1. The power storage device 101 can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV), and one embodiment thereof is shown in FIG.

Since the storage element according to the present invention can suppress damage to the lithium ion supply layer when the storage element is housed in the exterior body, the electric vehicle (EV), the hybrid vehicle (HEV), and the plug-in hybrid It can be effectively used as a power source for automobiles such as automobiles (PHEV), a power source for electronic devices and a power storage power source.

1: Power storage element 2: Exterior body 3: Power storage element 30: Exterior body 31: Positive electrode 32: Negative electrode 37: Separator 40: Bottom wall 41: Inner surface 42: Lithium ion supply layer 61: Protection member 100: Power storage unit 101: Power storage device 102: Body body 103: Automobile

Claims

An exterior body,
A power storage element including a negative electrode housed in the exterior body;
A lithium ion supply layer for supplying lithium ions to the negative electrode housed in the exterior body,
The lithium ion supply layer is a power storage element formed on a bottom surface of the exterior body.
The power storage element is a wound power storage element in which the negative electrode, the positive electrode, and the separator are wound.
The wound power storage element has a substantially oval cross-sectional shape in a direction perpendicular to the winding axis,
2. The power storage element according to claim 1, wherein the lithium ion supply layer is formed between a portion having a curved shape of the wound power storage element and a bottom surface in the exterior body.
The electric storage element according to claim 1 or 2, wherein the lithium ion supply layer is formed by applying a mixture containing a lithium ion supplier to the bottom surface of the outer package.
The electric storage element according to any one of claims 1 to 3, wherein a surface of the lithium ion supply layer is covered with an insulating sheet through which lithium ions pass.
The region of the inner surface of the outer package in which the lithium ion supply layer is formed is rougher than the region of the inner surface of the outer package in which the lithium ion supply layer is not formed. The electricity storage device according to one item.
The electric storage element according to any one of claims 1 to 5, wherein a resistance film is formed in a region of an inner surface of the exterior body on which the lithium ion supply layer is formed.
A power storage device comprising a plurality of power storage elements according to any one of claims 1 to 6.
An automobile provided with the power storage device according to claim 7.