JP2014135255A - Electricity storage element and on-vehicle storage battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electricity storage element capable of suppressing deterioration in output, and an on-vehicle storage battery system.SOLUTION: An electricity storage element includes a case 2, a power generation element 10 accommodated in the case 2, and an electrolyte 3 accommodated in the case 2. The power generation element 10 includes a positive electrode, a negative electrode, and a separator arranged between the positive electrode and the negative electrode and having an organic liquid and an electrolyte. In the separator, the absorbing speed of the organic liquid in the long side surface direction of the case 2 and the absorbing speed of the organic liquid in the height direction of the case 2 are 0.08 mm/min or more, and when a ratio of the length (width L) of the long side surface relative to the height Lof the case 2 is denoted as A, and a ratio of the absorbing speed in the long side surface direction relative to the absorbing speed in the height direction of the separator is denoted as B, B/A is in the range from 0.40 or more to 2.40 or less. When the width W is larger than the height H in the separator, the ratio of the absorbing speed in the long side surface direction relative to the absorbing speed in the height direction is 0.60 or more in the separator.

Description

  The present invention relates to a power storage element and an in-vehicle storage battery system.

  In recent years, as a power source for automobiles, motorcycles and other vehicles, portable terminals, notebook computers, and other various devices, batteries such as lithium ion batteries and nickel metal hydride batteries and capacitors such as electric double layer capacitors can be discharged and recharged. The element is adopted. A lithium ion secondary battery as an example of such a storage element is disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-243672 (Patent Document 1).

  The lithium ion secondary battery of Patent Document 1 includes a positive electrode, a negative electrode, a separator, a main electrolyte, a main container that stores these, a sub-electrolyte, and a sub-container that stores this sub-electrolyte. The sub-container is configured to supply the sub-electrolyte to the main container so as to replenish the main electrolyte that decreases with the use of the lithium ion secondary battery. Patent Document 1 describes that a long-life lithium secondary battery can be provided by replenishing an electrolytic solution that gradually decreases as the lithium ion secondary battery is used without opening the battery. Yes.

JP 2012-243672 A

  When the lithium ion secondary battery of Patent Document 1 is used, the electrolytic solution may flow out, causing at least partial liquid erosion, or uneven distribution of the electrolytic solution. When liquid withering or uneven distribution of the electrolyte occurs, there is a problem that the resistance of the lithium ion secondary battery increases and the output decreases.

  An object of this invention is to provide the electrical storage element which can suppress the fall of an output, and the vehicle-mounted storage battery system in view of the said problem.

  An electricity storage element according to one aspect of the present invention includes a container, a power generation element accommodated in the container, an electrolytic solution that is accommodated in the container and includes an organic liquid and an electrolyte dissolved in the organic liquid. The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and at least a part of the separator is in contact with the electrolytic solution, and the separator has a long side surface direction. The wicking speed of the organic liquid (hereinafter also referred to as the long side direction) and the wicking speed of the organic liquid in the height direction of the container (hereinafter also referred to as the height direction) are 0.08 mm / min or more. The ratio of the length of the long side surface to the height of the container is A, and the ratio of the wicking speed of the organic liquid in the long side direction of the container to the wicking speed of the organic liquid in the height direction of the container in the separator is B. / A is 0.4 Or more and 2.40 or less.

  According to the electricity storage device of one aspect of the present invention, the suction speed of the electrolyte in the height direction and the long side surface direction of the separator is 0.08 mm / min or more, and the length / height of the long side surface of the container. The ratio (A / B) of the suction speed in the long side surface direction / the suction speed in the height direction (= B) with respect to (= A) is within the above range. Thereby, since the wicking speed of the electrolyte solution in the long side surface direction and the height direction of the separator corresponds to the shape of the power storage element, partial liquid withering and uneven distribution of the electrolyte solution can be reduced. Therefore, since an increase in resistance can be suppressed, a power storage element that can suppress a decrease in output can be provided.

  An electricity storage device according to another aspect of the present invention includes a container, a power generation element housed in the container, an organic liquid housed in the container and an electrolyte dissolved in the organic liquid. The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and at least a part of the separator is in contact with the electrolytic solution, and in the separator, the height direction of the container The length of the container in the long side direction is larger than the length of the container. In the separator, the organic liquid suction speed in the long side direction of the container and the organic liquid suction speed in the height direction of the container are 0.08 mm / min. In the separator, the ratio of the wicking speed of the organic liquid in the height direction of the container to the wicking speed of the organic liquid in the long side surface direction of the container is 0.60 or more.

  The present inventor has disclosed that a portion of the organic liquid in the electrolyte solution of the separator in the height direction is fast even if the suction speed of the organic liquid in the electrolyte solution in the long side surface direction of the separator is not more than a predetermined value. It has been found that there is a case where a typical liquid withering occurs or an electrolyte is unevenly distributed. Note that the present inventor has stipulated that the speed of sucking up the electrolytic solution is mainly governed by the speed of sucking up the organic liquid. In view of this, the horizontal power storage device according to another aspect of the present invention is configured such that the suction speed of the organic liquid in the long side direction with respect to the suction speed of the organic liquid in the height direction is 0.60 or more, and Since the wicking speed of the electrolyte in the vertical direction is made to correspond to the shape of the power storage element, it is possible to reduce the occurrence of partial liquid erosion and the uneven distribution of the electrolyte. Therefore, since resistance can be suppressed in the horizontal power storage element, a power storage element that can suppress a decrease in output can be provided.

  In the electricity storage device according to another aspect of the present invention, preferably, the ratio of the length of the long side surface to the height of the container is A, and the length of the container in the separator relative to the wicking speed of the organic liquid in the height direction of the container in the separator. When the ratio of the wicking speed of the organic liquid in the lateral direction is B, B / A is 0.40 or more and 2.40 or less.

  Since the wicking speed of the organic liquid in the long side direction and the height direction of the separator corresponds to the shape of the electricity storage element, the case where partial liquid withering occurs and the case where the electrolyte is unevenly distributed is further reduced can do. Therefore, it is possible to further suppress a decrease in the output of the power storage element.

  An electricity storage element in still another aspect of the present invention includes a container, a power generation element accommodated in the container, an organic liquid accommodated in the container, and an electrolyte dissolved in the organic liquid; The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and at least a part of the separator is in contact with the electrolytic solution. The length in the height direction of the container is greater than or equal to the length in the direction, and in the separator, the suction speed of the organic liquid in the long side direction of the container and the suction speed of the organic liquid in the height direction of the container are In the separator, the ratio of the wicking speed of the organic liquid in the height direction of the container to the wicking speed of the organic liquid in the long side direction of the container is 0.60 or more.

  According to the electricity storage device of still another aspect of the present invention, the wicking speed of the organic liquid in the height direction and the long side surface direction of the separator is 0.08 mm / min or more, and the wicking speed in the height direction of the separator. / The wicking speed (= B) in the long side surface direction is within the above range. As a result, the wicking speed of the electrolyte in the long side direction and the height direction of the separator corresponds to the shape of the vertical power storage element, so that partial drainage and uneven distribution of the electrolyte can be reduced. it can. Therefore, since an increase in resistance can be suppressed, a power storage element that can suppress a decrease in output can be provided.

  Preferably, in the electricity storage device in the above-mentioned further aspect, the ratio of the length of the long side to the height in the container is A, and the long side direction of the container in the separator with respect to the wicking speed of the organic liquid in the height direction of the container in the separator If the ratio of the wicking speed of the organic liquid is B, B / A is 0.40 or more and 2.40 or less.

  Since the wicking speed of the electrolyte in the long side direction and the height direction of the separator is appropriate according to the shape of the vertical power storage element, partial drainage and uneven distribution of the electrolyte can be further reduced. . Therefore, it is possible to further suppress a decrease in the output of the power storage element.

  The in-vehicle storage battery system of the present invention includes any one of the above storage elements and a control unit that controls charging / discharging of the storage elements.

  According to the in-vehicle storage battery system of the present invention, the storage element that can suppress the decrease in output is provided. Therefore, the in-vehicle storage battery system can suppress a decrease in output.

  As described above, the present invention can provide a power storage element and an in-vehicle storage battery system that can suppress a decrease in output.

It is a perspective view which shows roughly the nonaqueous electrolyte secondary battery which is an example of the electrical storage element in Embodiment 1 of this invention. It is a perspective view which shows roughly the inside of the container of the nonaqueous electrolyte secondary battery in Embodiment 1 of this invention. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2, and is a cross-sectional view schematically showing the nonaqueous electrolyte secondary battery in the first embodiment of the present invention. It is a schematic diagram which shows roughly the electric power generation element which comprises the nonaqueous electrolyte secondary battery in Embodiment 1 of this invention. It is an expansion schematic diagram which shows roughly the positive electrode and negative electrode which comprise the electric power generation element in Embodiment 1 of this invention. It is a schematic diagram which shows schematically the inside of the nonaqueous electrolyte secondary battery in Embodiment 2 of this invention. It is a schematic diagram which shows the storage battery system in Embodiment 3 of this invention, and the state which mounted this in the vehicle. It is a figure for demonstrating the measuring method of the suction speed of the separator in an Example. It is a figure which shows the result of having measured the wicking speed | velocity | rate of the separator in an Example. It is a figure which shows the result of having measured the resistance of the lithium ion secondary battery in an Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
With reference to FIGS. 1-5, the nonaqueous electrolyte secondary battery 1 which is an example of the electrical storage element which is one embodiment of this invention is demonstrated. The nonaqueous electrolyte secondary battery 1 of the present embodiment is a horizontal type and includes a winding type power generation element.

  As shown in FIGS. 1 to 3, the nonaqueous electrolyte secondary battery 1 of the present embodiment includes a container 2, an electrolytic solution 3 accommodated in the container 2, and an external gasket 5 attached to the container 2. The power generation element 10 accommodated in the container 2, the current collector 7 electrically connected to the power generation element 10, and the external terminal 21 electrically connected to the current collector 7 are provided.

  As shown in FIG. 1, the container 2 includes a main body (case) 2a that houses the power generation element 10 and a lid 2b that covers the main body 2a. The main body 2a and the lid 2b are formed of, for example, a stainless steel plate and are welded to each other.

  An external gasket 5 is disposed on the outer surface of the lid 2b, and the opening of the lid 2b and the opening of the external gasket 5 are connected. The external gasket 5 has, for example, a recess, and the external terminal 21 is disposed in the recess.

  The external terminal 21 is connected to the current collector 7 (see FIG. 3) connected to the power generation element 10 and is electrically connected to the power generation element 10. The shape of the current collector 7 is not particularly limited, but is, for example, a plate shape. The external terminal 21 is made of an aluminum metal material such as aluminum or an aluminum alloy.

  The external gasket 5 and the external terminal 21 are provided for a positive electrode and a negative electrode. The external gasket 5 and the external terminal 21 for the positive electrode are disposed on one end side in the longitudinal direction of the lid portion 2b, and the external gasket 5 and the external terminal 21 for the negative electrode are disposed on the other end side in the longitudinal direction of the lid portion 2b. ing.

  As shown in FIGS. 2 and 3, the electrolytic solution 3 is accommodated in the main body 2 a, and the power generation element 10 is immersed in the electrolytic solution 3. As shown in FIG. 3, when the nonaqueous electrolyte secondary battery 1 is placed, the electrolyte 3 is stored as a surplus electrolyte in the lower part of the container 2, and a part of the separator 12 of the power generation element 10 is a surplus electrolyte. It is in contact with the electrolytic solution 3 as. That is, the electrolytic solution 3 as the surplus electrolytic solution is accommodated in at least a part of the region excluding the power generation element 10 in the internal space of the container 2 and is in contact with at least a part of the separator 12.

In the electrolytic solution 3, an electrolyte is dissolved in an organic solution (for example, an organic solvent). Examples of the organic solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), and γ-butylactone (γ-BL) as an ester solvent. And organic solvents formed by blending ether solvents such as diethoxyethane (DEE). Examples of the electrolyte include lithium salts such as lithium perchlorate (LiClO ₄ ), lithium borofluoride (LiBF ₄ ), and lithium hexafluorophosphate (LiPF ₆ ).

  The electrolytic solution 3 has a salt concentration of 0.5 to 1.4 mol, and preferably has a salt concentration of 0.8 to 1.2 mol. In this case, it is easy to control the wicking speed of the organic solution in the electrolytic solution 3 in the separator 12 described later within a predetermined range.

  As shown in FIG.2 and FIG.3, the electric power generation element 10 is accommodated in the inside of the main-body part 2a. In the container 2, one power generation element may be accommodated, or a plurality of power generation elements may be accommodated. In the latter case, the plurality of power generation elements 10 are electrically connected in parallel.

  The power generation element 10 is horizontally long with a width larger than the height, and the winding axis is in the width direction (long side surface direction in FIG. 3).

  As shown in FIG. 4, the power generation element 10 includes a positive electrode 11, a separator 12, and a negative electrode 13. The power generation element 10 has a separator 12 disposed on a negative electrode 13, a positive electrode 11 disposed on the separator 12, and is wound in a state where the separator 12 is disposed on the positive electrode 11, thereby forming a cylindrical shape. . That is, in the power generation element 10, the separator 12 is formed on the outer peripheral side of the negative electrode 13, the positive electrode 11 is formed on the outer peripheral side of the separator 12, and the separator 12 is formed on the outer peripheral side of the positive electrode 11. In the present embodiment, in the power generation element 10, since the insulating separator is disposed between the positive electrode 11 and the negative electrode 13, the positive electrode 11 and the negative electrode 13 are not electrically connected.

  As shown in FIG. 5, the positive electrode 11 constituting the power generation element 10 includes a positive electrode current collector foil 11A and a positive electrode mixture layer 11B formed on the positive electrode current collector foil 11A. The negative electrode 13 constituting the power generating element 10 includes a negative electrode current collector foil 13A and a negative electrode mixture layer 13B formed on the negative electrode current collector foil 13A. In the present embodiment, the positive electrode mixture layer 11B and the negative electrode mixture layer 13B are formed on the front surface and the back surface of the positive electrode current collector foil 11A and the negative electrode current collector foil 13A, respectively. It is not limited. For example, the positive electrode mixture layer 11B and the negative electrode mixture layer 13B may be formed on the front surface or the back surface of the positive electrode current collector foil 11A and the negative electrode current collector foil 13A. However, the negative electrode mixture layer 13B faces the positive electrode mixture layer 11B.

  In this embodiment, the positive electrode current collector foil and the negative electrode current collector foil are described as examples of the positive electrode substrate and the negative electrode substrate. However, in the present invention, the positive electrode substrate and the negative electrode substrate are foils. It is not limited to the shape.

  The positive electrode mixture layer 11B includes a positive electrode active material, a conductive additive, and a binder. The negative electrode mixture layer 13B has a negative electrode active material and a binder. The negative electrode mixture layer 13B may further have a conductive auxiliary agent.

The positive electrode active material is a material that can contribute to the electrode reaction of the charge reaction and the discharge reaction in the positive electrode. The material of the positive electrode active material is not particularly limited. For example, lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ) can be used.

  The negative electrode active material is a substance that can contribute to the electrode reaction of the charge reaction and the discharge reaction in the negative electrode. The material of the negative electrode active material is not particularly limited, and for example, carbon-based materials such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, and graphite can be used.

  The binder is not particularly limited. For example, polyacrylonitrile, polyvinylidene fluoride (PVDF), a copolymer of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, Sphazen, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, polycarbonate, and the like can be used.

  The separator 12 is disposed between the positive electrode 11 and the negative electrode 13 and allows the electrolytic solution 3 to pass while blocking the electrical connection between the positive electrode 11 and the negative electrode 13.

  The separator 12 preferably has a thickness of 15 μm to 25 μm, more preferably 20 μm to 24 μm. Thereby, the strength of the separator 12 can be maintained.

  Here, the thickness of the separator 12 is a value measured using a micrometer (manufactured by MITSUTOYO).

  The separator 12 preferably has an air permeability of 30 seconds / 100 cc to 300 seconds / 100 cc, more preferably 80 seconds / 100 cc to 260 seconds / 100 cc. Thereby, the strength of the separator 12 can be maintained.

  The air permeability is a value measured according to JIS P8117.

  The separator 12 may be a single layer, but may include a base material and an inorganic layer formed on one surface of the base material.

  When the separator 12 includes a base material and an inorganic layer, the base material is not particularly limited, and general resin porous membranes can be used. For example, polymer, natural fiber, hydrocarbon fiber, glass fiber, or ceramic fiber fabric Or non-woven fibers can be used.

The inorganic layer is also referred to as an inorganic coating layer, and includes, for example, inorganic particles and a binder. The inorganic particles are not particularly limited, and for example, oxide fine particles such as iron oxide, SiO ₂ , Al ₂ O ₃ , TiO ₂ , BaTiO ₂ , ZrO, alumina-silica composite oxide, and nitride such as aluminum nitride and silicon nitride. Fine particles, poorly soluble ion crystal particles such as calcium fluoride, barium fluoride and barium sulfate, covalently bonded crystal particles such as silicon and diamond, clay particles such as talc and montmorillonite, boehmite, zeolite, apatite, kaolin and mullite , Spinel, olivine, sericite, bentonite, mica, and other mineral resource-derived substances or their artificial products.

  Since the binder is the same as that of the positive electrode and the negative electrode, description thereof will not be repeated.

  In addition, the base material and the inorganic layer may be composed of a single layer, or may be composed of a plurality of layers.

  In the separator 12, the suction speed of the organic solution in the electrolyte solution 3 in the width direction (long side direction in FIG. 3) and the height direction (height direction in FIG. 3) in the predetermined measurement method (long side direction of the separator 12). And the suction speed in the height direction) is 0.08 mm / min or more, preferably 0.09 mm / min or more, and more preferably 0.11 mm / min or more. In the separator 12, the wicking speed in directions other than the long side direction and the height direction is not particularly limited, but the wicking speed in directions other than the long side direction and the height direction may be 0.08 mm or more. preferable.

  Here, the wicking speed of the separator means the speed of sucking (absorbing) an organic solution (hereinafter, an organic solvent is taken as an example) measured by the following method. Specifically, a separator test piece cut into a size of 2.5 × 8.0 cm was prepared, the sealed container containing the test piece was filled with the saturated vapor pressure of the organic solvent, and the temperature in the sealed container was adjusted. The height at which the organic solvent is sucked up every predetermined time after normal temperature (25 ± 3 ° C), one end of the test piece is fixed and suspended, and the other end is immersed in the organic solvent Is a value that can be measured by measuring the height and determining the rate of change in height. As the organic solvent for measurement, for example, a mixed solvent of ethylene carbonate (EC): diethyl carbonate (DEC) = 1: 1 can be used.

  Here, the long side surface direction of the separator 12 is the direction of the long side of the bottom surface 12a1, that is, the left-right direction in FIG. In the separator 12, the length (width W) in the long side surface direction of the container 2 is larger than the length (height T) in the height direction of the container 2, and the winding axis of the power generation element 10 is in the lateral direction (in FIG. 3). When the separator 12 is wound in the right and left direction, the long side surface direction in the separator 12 is a direction parallel to the winding axis, that is, a short side direction of a long sheet before winding.

  The height direction of the separator 12 is the length in the direction perpendicular to the bottom surface 12a1, and is the vertical direction in FIG. When the width W is larger than the height T in the separator 12 and the winding shaft of the power generation element 10 is wound in the lateral direction (left and right direction in FIG. 3), the height direction of the separator 12 is The direction is perpendicular to the axis, that is, the long side direction of the long sheet before winding.

  The width W in the separator 12 is the length in the direction of the long side of the bottom surface 12a1, and is the length in the left-right direction (long side surface direction) in FIG. In the separator 12, the length (width W) in the long side surface direction of the container 2 is larger than the length (height T) in the height direction of the container 2, and the winding axis of the power generation element 10 is in the lateral direction (in FIG. 3). When wound in the left-right direction), the width W of the separator 12 is the length in the direction parallel to the winding axis, that is, the length of the short side of the long sheet before winding.

  The height T in the separator 12 is the length in the direction perpendicular to the bottom surface 12a1, and is the vertical direction (height direction) in FIG. When the width W is larger than the height T in the separator 12 and the winding shaft of the power generation element 10 is wound in the lateral direction (left and right direction in FIG. 3), the height T in the separator 12 is the winding It is the length in the direction perpendicular to the axis, that is, the length between the terminal-side R portion vertex and the bottom-side R portion vertex of the wound product after winding.

  The wicking speed in the long side direction of the separator 12 is 0.08 mm / min or more, preferably 0.09 mm / min or more, more preferably 0.11 mm / min or more. The wicking speed in the height direction of the separator 12 is 0.08 mm / min or more, preferably 0.12 mm / min or more, more preferably 0.14 mm / min or more.

  In the separator 12, the ratio (B) of the suction speed in the long side direction to the suction speed in the height direction is 0.60 or more, preferably 0.65 or more, more preferably 0.95 or more. is there. The upper limit is 1.54 or less, for example. This is because the higher the ratio (B) of the suction speed in the container long side direction to the suction speed in the container height direction, the electrolyte solution is supplied from the long side direction in addition to the height direction. This is because there are at least two paths for supplying the electrolyte, and it is possible to further suppress uneven distribution of the electrolyte and partial drainage.

Height of the container 2 the width to (the height L ₂ in FIG. 3) the ratio of (width L ₁ in FIG. 3) (the width L ₁ / height L ₂₎ is A, in the height direction (FIG. 3 of the separator 12 If the ratio of the wicking speed in the width direction (long side direction in FIG. 3) to the wicking speed in the height direction is B, B / A is 0.40 or more and 2.40 or less, preferably 1.00. It is above 2.00.

Here, the width L ₁ of the container 2 is the long side (when the bottom is rectangular) or the long axis (when the bottom is oval) in the bottom surface 2a1, and is the left-right direction (long side direction, winding) in FIG. Length in a direction parallel to the axis). Between the height L ₂ is a container 2, a length in the direction perpendicular to the bottom surface 2a1, the length of the vertical direction in FIG. 3 (a height direction, a direction perpendicular to the winding axis).

  When the nonaqueous electrolyte secondary battery 1 includes a plurality of power generation elements 10, it is sufficient that the separator 12 constituting at least one power generation element 10 has the above suction speed. It is preferable that the separator 12 which comprises comprises the said wicking speed.

Then, the manufacturing method of the nonaqueous electrolyte secondary battery 1 in this Embodiment is demonstrated.
First, the power generation element 10 will be described.

  A positive electrode active material, a conductive additive, and a binder are mixed, and this mixture is added to a solvent and kneaded to form a positive electrode mixture. This positive electrode mixture is applied to at least one surface of the positive electrode current collector foil 11A, dried, and then compression molded. Thereby, the positive electrode 11 in which the positive electrode mixture layer 11B is formed on the positive electrode current collector foil 11A is manufactured. After compression molding, vacuum drying is performed.

  A negative electrode active material such as graphite, hard carbon, and soft carbon and a binder are mixed, and this mixture is added to a solvent and kneaded to form a negative electrode mixture. This negative electrode mixture is applied to at least one surface of the negative electrode current collector foil 13A, dried, and then compression molded. Thereby, the negative electrode 13 in which the negative electrode mixture layer 13B is formed on the negative electrode current collector foil 13A is produced. After compression molding, vacuum drying is performed.

In the present embodiment, with respect to the raw material base material to be the separator 12, the suction speed corresponding to the longitudinal direction of the container 2 and the suction direction corresponding to the height direction of the container 2 after the production of the power generation element 10 using the same. The upper speed is measured, the long side direction and the height direction are determined so as to satisfy the condition i) and the condition ii) and / or the condition iii), and the separator 12 is formed from the raw material substrate.
Condition i) The suction speed in the long side direction and the suction speed in the height direction are 0.08 mm / min or more.
Condition ii) If the ratio of the width L ₁ to the height L ₂ of the container 2 is A and the ratio of the suction speed in the long side direction to the suction speed in the height direction of the separator 12 is B, B / A is 0 .40 or more and 2.40 or less.
Condition iii) The ratio of the suction speed in the long side direction to the suction speed in the height direction is 0.60 or more.

  The raw material substrate of the separator 12 is preferably a resin sheet, and more preferably a porous film mainly composed of polyethylene or polypropylene, for example.

  The raw material base material of the separator 12 may be produced by preparing a base material and forming an inorganic layer by applying a coating agent on the base material.

  Here, the effect by the manufacturing method of a separator is demonstrated. In a method using a biaxial stretching method or a uniaxial stretching method, which is a conventional separator manufacturing method, the stretching ratio in the longitudinal direction is considerably larger than the stretching ratio in the width direction. However, in the conventional method, since the holes in the separator have an elliptical shape with the longitudinal direction as the long side, liquid suction in the width direction is hindered, and the suction speed in the width direction tends to decrease. For this reason, unlike the conventional case, by keeping the draw ratio in the longitudinal direction low or by increasing the draw ratio in the width direction, the container length direction (long side direction) and the container It is possible to manufacture a separator in which the suction speed in the height direction is appropriately controlled.

  Next, the positive electrode 11 and the negative electrode 13 are wound through the separator 12. Thereby, the electric power generation element 10 is produced. Thereafter, the current collector 7 is attached to each of the positive electrode 11 and the negative electrode 13.

  Next, the power generation element 10 is disposed inside the main body 2 a of the container 2. In the case where there are a plurality of power generation elements 10, for example, the current collectors of the power generation elements 10 are electrically connected in parallel and arranged inside the main body 2a. Next, the current collectors are respectively welded to the external terminals 21 in the external gasket 5 of the lid 2b, and the lid 2b is attached to the main body 2a.

Next, an electrolytic solution is injected. The electrolytic solution is not particularly limited, but the salt concentration is preferably 0.8 mol / L or more and 1.2 mol / L or less. As such an electrolytic solution, for example, LiPF ₆ may be prepared in a mixed solvent of propylene carbonate (PC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 3: 4: 3 (volume ratio). . Moreover, a well-known additive may be further added. Through the above steps, the nonaqueous electrolyte secondary battery 1 in the present embodiment shown in FIGS. 1 to 5 is manufactured.

(Modification)
The nonaqueous electrolyte secondary battery in the modification is basically the same as that of the first embodiment described above, but differs in that the power generation element 10 is not a winding type but a stacked type.

  Specifically, the power generation element includes a separator 12 disposed on the negative electrode 13, a positive electrode 11 disposed on the separator 12, and a stacked state in which the separator 12 is disposed on the positive electrode 11. Be contained.

  In the modification, the width direction of the separator is the direction of the long side on the bottom surface, which is the left-right direction in FIG. The height direction of the separator 12 is a short side direction on the bottom surface, and is a vertical direction in FIG.

As described above, the nonaqueous electrolyte secondary battery 1 which is an example of the power storage element in the present embodiment and its modification is accommodated in the container 2, the power generation element 10 accommodated in the container 2, and the container 2. The power generation element 10 includes a positive electrode 11, a negative electrode 13, and a separator disposed between the positive electrode 11 and the negative electrode 13, and an electrolyte solution 3 having an organic liquid and an electrolyte dissolved in the organic liquid. 12, at least a part of the separator 12 is in contact with the electrolytic solution, and the separator 12 absorbs the organic liquid in the electrolytic solution 3 in the long side surface direction (long side surface direction in FIG. 3) of the container 2. The wicking speed of the organic liquid in the electrolytic solution 3 in the velocity direction and the height direction of the container 2 (height direction in FIG. 3) is 0.08 mm / min or more, and the width (length) of the container _{2 with} respect to the height L ₂ Side length) L ₁ ratio (L ₁ / L ₂ ) is A, and the suction of the separator 12 in the long side direction (long side direction in FIG. 3) with respect to the suction speed of the organic liquid in the height direction of the container 2 (height direction in FIG. 3). If the ratio of the upper speed is B, B / A is 0.40 or more and 2.40 or less.

According to the nonaqueous electrolyte secondary battery 1 in the present embodiment and its modification, the wicking speed of the organic liquid in the electrolyte solution in the height direction and the long side direction of the separator 12 is 0.08 mm / min or more. Thus, when the mounting surface is the bottom surface 2a1 (see FIGS. 1 and 3) of the main body 2a of the container 2, the electrolyte 3 is absorbed toward the height direction and the long side surface direction of the separator 12. be able to. That is, the effective path for supplying the electrolyte solution 3 to the separator 12 is not only the height direction of the separator 12 but also at least two directions of the height direction and the long side surface direction.
The ratio (B / A) of the wicking speed in the long side surface direction / the wicking speed in the height direction (= B) to the width L ₁ / height L ₂ (= A) of the container 2 is 0.40 or more and 2 When the mounting surface is the bottom surface 2a1 (see FIG. 1) of the main body portion 2a of the container 2, the wicking speeds in both the long side surface direction and the height direction can be increased. Since it is appropriate according to the shape of the secondary battery 1, it becomes easy to supply the electrolytic solution 3 to the entire separator 12. For this reason, since generation | occurrence | production of partial liquid erosion and the uneven distribution of the electrolyte solution 3 can be reduced, charging / discharging reaction can be accelerated | stimulated by suppressing that the electrolyte solution 3 is exhausted. Therefore, since an increase in electrical resistance can be suppressed, a decrease in the output of the nonaqueous electrolyte secondary battery 1 can be suppressed.

  Further, the nonaqueous electrolyte secondary battery 1 in the present embodiment and its modification is a container 2, a power generation element 10 accommodated in the container 2, an organic liquid accommodated in the container 2, and the organic liquid The power generation element 10 includes a positive electrode 11, a negative electrode 13, and a separator 12 disposed between the positive electrode 11 and the negative electrode 13, and at least one of the separators 12. The part is in contact with the electrolytic solution 3, and in the separator 12, the length in the long side surface direction (width W) of the container is larger than the length in the container height direction (height T). The suction speed of the organic liquid in the electrolytic solution 3 in the long side direction (the long side direction in FIG. 3) of the container 2 and the organic liquid in the electrolytic solution 3 in the height direction of the container 2 (the height direction in FIG. 3). Suction speed is 0.08mm / min or less In the separator 12, the ratio of the wicking speed in the long side direction of the container (long side direction in FIG. 3) to the wicking speed of the organic liquid in the height direction of the container 2 (height direction in FIG. 3) (B ) Is 0.6 or more.

  In the conventional non-aqueous electrolyte secondary battery 1, it has been considered to increase the suction speed in the height direction of the separator in order to reduce liquid withering and uneven distribution of the electrolytic solution. However, even if the suction speed in the height direction of the separator 12 is high, the present inventor has found that if the suction speed in the long side surface direction is not equal to or higher than a predetermined level, partial liquid drainage occurs, It was found that uneven distribution may occur. In such a case, the charge / discharge reaction does not proceed in the region where the electrolytic solution is depleted, and the charge / discharge reaction amount of the positive electrode and the negative electrode becomes excessively large in the region where the electrolytic solution is retained. Then, as a result of examining the suction speed in the long side direction that can reduce partial liquid withering and uneven distribution of the electrolyte, when the placement surface is the bottom surface 2a1 of the main body 2a of the container 2, It has been found that the electrolyte solution 3 can be rapidly supplied to the entire separator 12 by setting the suction speed in the long side direction to 0.6 or more with respect to the suction speed. Therefore, in the horizontal type nonaqueous electrolyte secondary battery 1 of the present embodiment and its modification, an increase in resistance can be suppressed, and a decrease in output can be suppressed.

  In addition, although the wicking speed | rate of the electrolyte solution in the separator 12 can be raised by raising the wicking speed | rate of the organic liquid in the electrolyte solution in the separator 12 by making the intensity | strength of the separator 12 low, this Embodiment The separator 12 of the nonaqueous electrolyte secondary battery 1 can quickly supply the electrolyte solution to the entire separator 12 while maintaining strength.

  Thus, since the nonaqueous electrolyte secondary battery 1 in the present embodiment and its modification can maintain the strength of the separator 12 and suppress a decrease in output, it is charged and discharged at a high temperature and several thousand cycles. In addition, it can be charged and discharged with a large current. Therefore, the nonaqueous electrolyte secondary battery 1 in the present embodiment is preferably for in-vehicle use, and more preferably for hybrid vehicles or electric vehicles.

(Embodiment 2)
With reference to FIG. 6, nonaqueous electrolyte secondary battery 30 which is an example of the electrical storage element in Embodiment 2 is demonstrated. The nonaqueous electrolyte secondary battery 30 of the second embodiment is basically the same as that of the first embodiment, but differs in that it is a vertical type.

  Specifically, in the separator constituting the power generation element of the nonaqueous electrolyte secondary battery 30, the height T is greater than or equal to the width W.

  Similar to the first embodiment, the separator has a wicking speed of the organic liquid in the electrolytic solution of 0.08 mm / min or more. That is, the wicking speed of the separator 12 means the speed of sucking up the organic liquid in the width direction (long side surface direction in FIG. 6) and the height direction (height direction in FIG. 6).

  Here, in the separator, when the width W is the same or smaller than the height T and the winding axis of the power generation element 10 is in the horizontal direction (left-right direction in FIG. 6), the width direction of the separator 12 is the winding width direction. (The direction parallel to the winding axis) and the height direction of the separator 12 is the winding circumferential direction (winding direction, direction perpendicular to the winding axis).

  In the separator 12, the ratio of the suction speed in the height direction to the suction speed in the long side direction (the suction speed in the height direction / the suction speed in the long side direction) is 0.60 or more.

As in the first embodiment, the container 2 height width to (the height L ₂ in FIG. 6) the ratio of (width L ₁ in FIG. 6) (the width L ₁ / height L ₂₎ is A, the separator The ratio of the suction speed in the width direction (long side surface direction in FIG. 6) to the suction speed in the height direction (height direction in FIG. 6) (the suction speed in the long side direction / the suction speed in the height direction). Assuming B, B / A is 0.40 or more and 2.40 or less.

Here, when the winding axis of the power generation element 10 is in the lateral direction (left-right direction in FIG. 6), the width L _{1 of the} container 2 is a direction parallel to the long side surface direction (direction parallel to the winding axis). The length is the length of the long side (when the bottom is rectangular) or the long axis (when the bottom is oval), and the height L ₂ of the container 2 is the height direction (on the winding axis) Vertical direction).

(Modification)
The nonaqueous electrolyte secondary battery in the modification is basically the same as that of the second embodiment described above, but differs in that the power generation element 10 is not a winding type but a stacked type.

  In the modification, the width direction of the separator is the short side surface direction of the container 2 in FIG. 6, and the height direction of the separator is the long side surface direction in FIG. 6.

  As described above, the non-aqueous electrolyte secondary battery 30 which is an example of the storage element in the present embodiment and the modification thereof includes the container 2, the power generation element 10 accommodated in the container 2, and the container 2. The power generation element 10 includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The power generation element 10 includes an electrolyte 3 containing an organic liquid and an electrolyte dissolved in the organic liquid. At least a part of the separator 12 is in contact with the electrolytic solution 3, and in the separator, the length in the height direction of the container 2 (FIG. 6) is longer than the length in the long side surface direction (width W in FIG. 6). The height T) of the container 2 is large or the same, and in the separator, the suction speed of the organic liquid in the electrolyte in the long side direction of the container 2 (long side direction in FIG. 6) and the height direction of the container 2 (FIG. Height direction at 6 In the stacked type, the wicking speed of the organic liquid in the electrolyte solution in the short side surface direction of the container 2 is 0.08 mm / min or more, and in the separator, in the long side direction of the container 2 (long side direction in FIG. 6). The wicking speed of the organic liquid in the height direction of the container 2 with respect to the wicking speed of the organic liquid (the height direction in FIG. 6, the short side surface direction of the container 2 in the stacked type) is 0.60 or more.

  According to the nonaqueous electrolyte secondary battery 30 in the present embodiment and the modification thereof, the wicking speed of the organic liquid in the electrolyte solution in the height direction and the long side surface direction of the separator is 0.08 mm / min or more. Thus, when the mounting surface is the bottom surface 2a1 of the main body 2a of the container 2, the electrolyte can be absorbed toward the height direction and the long side surface direction of the separator. That is, the effective path | route which supplies the electrolyte solution 3 to a separator becomes at least 2 directions of a height direction and a long side surface direction. Further, by setting the suction speed in the height direction of the separator / the suction speed in the long side direction (= B) to 0.60 or more, the suction speed of the electrolyte in the long side direction and the height direction of the separator can be increased. Since it is appropriate depending on the shape of the vertical power storage element, partial liquid withering and uneven distribution of the electrolyte can be reduced. Therefore, since an increase in electrical resistance can be suppressed, a decrease in the output of the nonaqueous electrolyte secondary battery 30 can be suppressed.

(Embodiment 3)
As shown in FIG. 7, in-vehicle storage battery system 100 according to the present embodiment includes nonaqueous electrolyte secondary battery 1 as the power storage element according to the first embodiment and / or nonaqueous electrolyte as the power storage element according to the second embodiment. A secondary battery 30 and a control unit 102 that controls charging / discharging of the nonaqueous electrolyte secondary battery 1 are provided. Specifically, the in-vehicle storage battery system 100 performs charge / discharge of the storage battery module 101 having a plurality of nonaqueous electrolyte secondary batteries 1 and the nonaqueous electrolyte secondary battery at a high rate, and controls the charge / discharge. And a control unit 102.

  When this in-vehicle storage battery system 100 is mounted on a vehicle 110, as shown in FIG. 7, a control unit 102 and a vehicle control device 111 that controls an engine, a motor, a drive system, an electrical system, etc. , CAN and other in-vehicle communication networks 112. The control part 102 and the vehicle control apparatus 111 communicate, and the storage battery system 100 is controlled based on the information obtained from the communication. Thereby, the vehicle provided with the storage battery system 100 is realizable.

  As described above, the in-vehicle storage battery system of the present embodiment includes the nonaqueous electrolyte secondary batteries 1 and 30 as the power storage elements of the first or second embodiment, and the nonaqueous electrolyte secondary batteries 1 and 30. And a control unit 102 that controls charging and discharging.

  According to the in-vehicle storage battery system 100 of the present embodiment, the storage element that can suppress the decrease in output is provided. Therefore, the in-vehicle storage battery system 100 can suppress a decrease in output.

  In this example, B / A when the ratio of the width to the height of the container is A and the ratio of the wicking speed in the width direction to the wicking speed in the height direction of the separator is B, and the electrolyte solution of the separator The effect when the wicking speed of the organic liquid was within a predetermined range was investigated. Further, in this example, the effect when the ratio B of the wicking speed in the width direction to the wicking speed in the height direction in the separator and the wicking speed of the organic liquid in the electrolyte of the separator are within a predetermined range. Investigated about.

Example 1
<Positive electrode>
Li _1.1 Ni _0.33 Co _0.33 Mn _0.33 O ₂ as a positive electrode active material, acetylene black as a conductive additive, and PVDF as a binder were mixed at a ratio of 90: 5: 5, and this mixture was used as a solvent. N-methylpyrrolidone (NMP) was added to form a positive electrode mixture. This positive electrode mixture was applied to both surfaces of an Al foil as the positive electrode current collector foil 11A. After drying, it was compression molded with a roll press. Thereby, the positive electrode 11 in which the positive electrode mixture layer 11B was formed on the positive electrode current collector foil 11A was produced.

<Negative electrode>
Hard carbon as a negative electrode active material and PVDF as a binder were mixed at a ratio of 95: 5, and NMP as a solvent was added to this mixture to form a negative electrode mixture. This negative electrode mixture was applied to both surfaces of a Cu foil as the negative electrode current collector foil 13A. After drying, it was compression molded with a roll press. Thereby, the negative electrode 13 in which the negative electrode mixture layer 13B was formed on the negative electrode current collector foil 13A was produced.

<Separator>
The separator of Example 1 was produced as follows. Specifically, a porous film mainly composed of polypropylene was prepared as a raw material substrate for the separator. A test piece having a width of 2.5 cm and a length of 8.0 cm was cut out from the raw material base material. As shown in FIG. 8, a test piece is sandwiched between clips, and a mixed solvent of ethylene carbonate (EC): diethyl carbonate (DEC) = 1: 1 as an organic solvent, which is an organic liquid contained in the electrolytic solution, is injected and sealed. The container is filled with the saturated vapor pressure of the organic solvent, the temperature in the sealed container is brought to room temperature, the tip of the test piece is immersed in the organic solvent, and the organic solvent is removed from the liquid surface of the organic solvent in the test piece every predetermined time. The height at which the was sucked was measured. The result is shown in FIG.
In the standing time of 30 to 90 minutes shown in FIG. 9, the uptake speed of the organic solvent was obtained by obtaining an approximate curve from FIG. 9 as the rate of change in height from the liquid surface. And in the raw material base material, the long side surface direction and the height direction were determined, and the separator was cut out. Thereby, the separator 12 of Example 1 was produced.

  The ratio (B) of the wicking speed in the width direction to the wicking speed in the height direction in the separator 12 of Example 1 manufactured as described above is shown in Tables 1 and 3 below.

  The thickness and air permeability of the separator 12 of Example 1 are shown in Table 2 below. The thickness of the separator 12 was measured using a micrometer (manufactured by MITSUTOYO). The air permeability of the separator 12 was measured according to JIS P8117.

<Power generation element>
Next, as shown in FIGS. 1 to 3, the positive electrode 11 and the negative electrode 13 were wound into a long cylindrical shape via the separator 12 so that the width W was larger than the height T. Thereby, the electric power generation element 10 was produced.

<Assembly>
A container 2 having a width L ₁ of 167.0 mm and a height L ₂ of 129.0 mm (width L ₁ > height L ₂ ) was prepared.
The current collector 7 is attached to each of the positive electrode 11 and the negative electrode 13 of the power generation element 10. The power generation element 10 is disposed inside the main body 2 a of the container 2. Next, the current collector 7 was welded to the external terminal 21 of the lid 2b, and the lid 2b was attached to the main body 2a.

Next, the electrolytic solution 3 was injected. The electrolytic solution 3 is dissolved in a mixed solvent of propylene carbonate (PC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 1: 1: 1 (volume ratio) so that LiPF ₆ is 1 mol / L. Prepared. As the surplus electrolyte, the bottom of the container 2 was filled with the electrolyte 3 such that the liquid level was 43.0 mm.

  Through the above process, the lithium ion secondary battery of Example 1 was manufactured. In the lithium ion secondary battery of Example 1, the battery dimensions (ratio A of the width to the height of the container) and B / A are shown in Table 3 below.

(Example 2)
The lithium ion secondary battery of Example 2 was basically the same as that of Example 1, but differed in that the draw ratios in the longitudinal direction and the width direction during the production of the separator were set low. For this reason, as described in Tables 1 to 3 below, the thickness and air permeability of the separator, the suction speed in the long side direction and the height direction, A, and B / A were different.

(Example 3)
The lithium ion secondary battery of Example 3 was basically the same as that of Example 1, but Example 3 was different in that an inorganic layer was applied on the resin base material layer. For this reason, the air permeability of the separator, the tensile strength in the long side direction, the tensile strength in the height direction, the suction speed in the long side direction and the height direction, A, and B / A were different.

(Example 4)
The lithium ion secondary battery of Example 4 was basically the same as that of Example 1, but Example 4 was different in that the stretch ratio in the longitudinal direction during the production of the separator was set higher than that of Example 1. It was. For this reason, the air permeability of the separator, the tensile strength in the long side direction, the tensile strength in the height direction, the suction speed in the long side direction and the height direction, A, and B / A were different.

(Example 5)
The lithium ion secondary battery of Example 5 was basically the same as that of Example 1, but Example 5 was different in that the container 2 used a more horizontally long container as compared with Example 1. It was. For this reason, the ratios A and B / A of the width with respect to the height of the container 2 were different.

(Evaluation method)
About the lithium ion secondary battery of Examples 1-5, after implementing a cycle of 1000 cycles with DCR (direct current resistance) before a cycle start and current value 60A, DCR (direct current resistance) after standing for each time was evaluated. . The results are shown in FIG.

(Evaluation results)

  As shown in Table 3 and FIG. 10, the wicking speed of the organic solvent in the long side direction and the height direction in the separator 12 is 0.08 mm / min or more, and B / A is 0.4 or more and 2.4 or less. Certain Examples 1 to 5 could suppress an increase in resistance.

  As shown in Table 3 and FIG. 10, the wicking speed of the organic solvent in the long side direction and the height direction in the separator 12 is 0.08 mm / min or more, and the long side face with respect to the wicking speed in the height direction in the separator. In Examples 1 to 5, in which the wicking speed in the direction is 0.60 or more, an increase in resistance can be suppressed.

  As shown in Table 1, the separators of Examples 1 and 2 have sufficient strength as separators used for lithium ion secondary batteries in consideration of thickness and air permeability. For this reason, it turned out that the separator 12 of the lithium ion secondary battery of Example 1 and 2 can maintain intensity | strength, and can suppress a raise of resistance.

  As described above, according to the present example, in the horizontal lithium secondary battery having a width larger than the height in the separator, the wicking speed in the width direction and the wicking speed in the height direction are 0.08 mm / min or more in the separator. And the ratio of the width to the height of the container is A, and the wicking speed in the width direction with respect to the wicking speed in the height direction of the separator is B, B / A is 0.40 or more and 2.40 or less. As a result, it was confirmed that the increase in resistance could be suppressed. Further, according to this example, in the horizontal lithium secondary battery having a width larger than the height of the separator, the width-wise wicking speed and the height-wise wicking speed are 0.08 mm / min or more. In addition, in the separator, it was confirmed that the increase in resistance can be suppressed when the ratio of the suction speed in the width direction to the suction speed in the height direction is 0.60 or more.

  In particular, in a horizontal lithium secondary battery having a width larger than the height of the separator, the wicking speed in the width direction and the wicking speed in the height direction are 0.08 mm / min or more in the separator, and high in the separator. The suction speed in the width direction with respect to the suction speed in the width direction is 0.60 or more, and the ratio of the width to the height of the container is A, and the suction speed in the width direction with respect to the suction speed in the height direction of the separator. Assuming that the ratio of B is B, it was confirmed that the increase in resistance can be suppressed when B / A is 0.40 or more and 2.40 or less.

  Here, in this example, the lateral type lithium ion secondary battery was examined for the organic solvent wicking speed, B, and B / A of the separator. The present inventor also examined that the present invention can be applied. As a result, in the vertical type lithium ion secondary battery, the separator has an organic solvent wicking speed of 0.08 mm / min or more, and the separator has a wicking speed in the height direction with respect to the wicking speed in the width direction. It has been found that the increase in resistance can be suppressed when the ratio B of the upper speed is 0.60 or more.

  As described above, the embodiments and examples of the present invention have been described, but it is also planned from the beginning to appropriately combine the features of the embodiments and examples. The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the embodiments and examples described above but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

  1,30 Non-aqueous electrolyte secondary battery, 2 container, 2a body part, 2a1 bottom face, 2b lid part, 3 electrolyte, 5 external gasket, 7 current collecting part, 10 power generation element, 11 positive electrode, 11A positive electrode current collector foil, 11B positive electrode mixture layer, 12 separator, 13 negative electrode, 13A negative electrode current collector foil, 13B negative electrode mixture layer, 21 external terminal, 100 storage battery system, 101 storage battery module, 102 control unit, 110 vehicle, 111 vehicle control device, 112 communication network.

Claims (6)

A container,
A power generation element housed in the container;
An electrolytic solution contained in the container and having an organic liquid and an electrolyte dissolved in the organic liquid;
The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode,
At least a portion of the separator is in contact with the electrolyte solution;
In the separator, the wicking speed of the organic liquid in the long side direction of the container and the wicking speed of the organic liquid in the height direction of the container are 0.08 mm / min or more,
The ratio of the length of the long side to the height in the container is A, and the wicking speed of the organic liquid in the long side direction of the container with respect to the wicking speed of the organic liquid in the height direction of the container in the separator A power storage element in which B / A is 0.40 or more and 2.40 or less, where B is a ratio. A container,
A power generation element housed in the container;
An electrolytic solution contained in the container and having an organic liquid and an electrolyte dissolved in the organic liquid;
The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode,
At least a portion of the separator is in contact with the electrolyte solution;
In the separator, the length in the long side direction of the container is larger than the length in the height direction of the container,
In the separator, the wicking speed of the organic liquid in the long side direction of the container and the wicking speed of the organic liquid in the height direction of the container are 0.08 mm / min or more,
In the separator, a ratio of a suction speed of the organic liquid in a height direction of the container to a suction speed of the organic liquid in a long side direction of the container is 0.60 or more.   The ratio of the length of the long side surface to the height of the container is A, and the absorption of the organic liquid in the long side direction of the container in the separator with respect to the wicking speed of the organic liquid in the height direction of the container in the separator. The electricity storage device according to claim 2, wherein B / A is 0.40 or more and 2.40 or less, where B is an upper speed ratio. A container,
A power generation element housed in the container;
An electrolytic solution contained in the container and having an organic liquid and an electrolyte dissolved in the organic liquid;
The power generation element includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode,
At least a portion of the separator is in contact with the electrolyte solution;
In the separator, the length in the height direction of the container is greater than or the same as the length in the long side direction of the container,
In the separator, the wicking speed of the organic liquid in the long side direction of the container and the wicking speed of the organic liquid in the height direction of the container are 0.08 mm / min or more,
In the separator, a ratio of a suction speed of the organic liquid in a height direction of the container to a suction speed of the organic liquid in a long side direction of the container is 0.60 or more.   The ratio of the length of the long side surface to the height in the container is A, and the organic liquid absorption in the long side direction of the container in the separator with respect to the wicking speed of the organic liquid in the height direction of the container in the separator. The electrical storage element according to claim 4, wherein B / A is 0.40 or more and 2.40 or less, where B is an upper speed ratio. The power storage device according to any one of claims 1 to 5,
An in-vehicle storage battery system comprising: a control unit that controls charging / discharging of the storage element.

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