JP2001243936A - Non-aqueous secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous secondary cell with superb heat resistance and safety. SOLUTION: This is a flat non-aqueous secondary cell provided with a positive electrode 101a, negative electrodes 101b, 101c, a separator 104, and a non- aqueous electrolyte including lithium salt has an energy capacity of 30 Wh or more and cubic energy density 180 Wh/liter or more. The separator consists of one or a plural sheets, at least one of which has heat contraction rate at 150 deg.C of not more than 5% at any part along the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous secondary battery, and more particularly to a non-aqueous secondary battery for a power storage system.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of effective use of energy for resource saving and global environmental problems, a home-use decentralized power storage system for late-night power storage and power storage for photovoltaic power generation has been developed. Power storage systems are attracting attention. For example, JP-A-6-86463 discloses that
As a system capable of supplying energy to an energy consumer under optimum conditions, a total system combining electricity supplied from a power plant, gas cogeneration, a fuel cell, a storage battery, and the like has been proposed. A secondary battery used in such a power storage system has an energy capacity of 10
Unlike small secondary batteries for portable devices of Wh or less, large batteries having large capacities are required. For this reason, in the above-described power storage system, a plurality of secondary batteries are stacked in series, and usually used as a battery pack having a voltage of, for example, 50 to 400 V. In most cases, a lead battery is used.

On the other hand, in the field of small rechargeable batteries for portable equipment, nickel-metal hydride batteries and lithium rechargeable batteries have been developed as new types of batteries in order to meet the needs of small size and high capacity, and volume energy of 180 Wh / l or more has been developed. Batteries having a density are commercially available. In particular, lithium-ion batteries
It has the potential of a volume energy density exceeding 350 Wh / l, and its reliability, such as safety and cycle characteristics, is superior to a lithium secondary battery using lithium metal as a negative electrode. Prolonged.

[0004] In response to this, in the field of large-sized batteries for power storage systems, lithium-ion batteries have been targeted as candidates for high-energy density batteries, and lithium battery power storage technology research associations (LIBES) and others have been vigorously developing them. Have been.

The energy capacity of these large lithium ion batteries is about 100 Wh to 400 Wh, and the volume energy density is 200 to 300 Wh / l, which is at the level of a small secondary battery for portable equipment. Its shape is
Diameter 50mm-70mm, length 250mm-450mm
And a rectangular prism having a thickness of 35 mm to 50 mm or an oblong prism or the like are typical.

[0006] As for the thin lithium secondary battery, for example, a film battery (for example, Japanese Patent Application Laid-Open Nos. Hei 5-159575 and Hei 7-15975) in which a thin film having a thickness of 1 mm or less in which metal and plastic are laminated is accommodated in a thin exterior. -5
No. 7788), a small rectangular battery having a thickness of about 2 mm to 15 mm (JP-A-8-195204, JP-A-8-195204).
138727, JP-A-9-213286, etc.) are known. The purpose of these lithium secondary batteries is to respond to the miniaturization and thinning of portable devices. For example, an area of about JIS A4 size with a thickness of several mm that can be stored on the bottom surface of a portable personal computer. Japanese Patent Application Laid-Open No. 5-28310 discloses a thin battery.
No. 5), since the energy capacity is 10 Wh or less, the capacity is too small for a secondary battery for a power storage system.

[0007]

Generally, in a small lithium-ion battery for a portable device, a separator currently has both a role of preventing a short circuit and a role of a fuse for stopping an electrochemical reaction when an abnormality occurs. In many cases, the separator is required to have various characteristics. Specifically,
Mechanical strength such as low resistance to obtain high efficiency, piercing strength against surface pressure from the electrode and high tensile strength required for winding specifications, shutdown characteristics to melt and close holes at high temperature, shape after melting Such as retention. Therefore, in most cases, a small-sized lithium-ion battery having an energy capacity of 5 Ah or less uses a microporous film having a thickness of 20 to 40 μm mainly composed of polyethylene.

When the battery is overcharged, short-circuited externally, or left in a high-temperature environment due to malfunction due to equipment failure or misuse by the user, the inside of the battery is heated and the electrolyte is decomposed or evaporated. Generates gas inside. Although a safety valve is provided on the lid or bottom of the container to prevent an accident due to an increase in internal pressure, the separator plays an important role as a further safety mechanism as described above. That is, when the battery internal temperature rises abnormally, the polyethylene-based separator is designed to start melting from around 120 ° C., close the pores, and suppress the reaction by increasing the battery internal resistance. ing.

However, the conventional polyethylene-based separator starts to shrink at the same time as the melting phenomenon of closing the pores at a high temperature, and the heat shrinkage at a high temperature of 150 ° C. is 10% in both the vertical and horizontal directions. Often this was the case. For this reason, the area of the separator surface may be smaller than the area of the electrode surface, or the separator may be broken at the time of large shrinkage deformation, which may cause an internal short circuit in which the positive electrode and the negative electrode come into direct contact, Problems such as thermal runaway of the battery occurred. In particular, such a problem was remarkable in a large battery having an energy capacity of 30 Wh or more.

An object of the present invention is to provide a non-aqueous secondary battery having excellent heat resistance and high safety in order to solve the above problems.

[0011]

According to the present invention, there is provided a flat non-aqueous secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt. The capacity is 30 Wh or more and the volume energy density is 180 Wh / l or more, and the separator is composed of one or more sheets, and at least one of the separators has a heat shrinkage rate at 150 ° C. in a direction along the surface. In any case, the present invention provides a non-aqueous secondary battery characterized by being 5% or less.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-aqueous secondary battery according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view and a side view of a flat rectangular (notebook) non-aqueous secondary battery for a power storage system according to an embodiment of the present invention. FIG. It is a side view which shows the structure of the electrode laminated body accommodated inside.

As shown in FIGS. 1 and 2, the non-aqueous secondary battery of this embodiment is housed in a battery case (battery container) including an upper lid 1 and a bottom container 2 and the battery case. An electrode stack including a plurality of positive electrodes 101a, negative electrodes 101b and 101c, and a separator 104 is provided.
In the case of a flat nonaqueous secondary battery as in the present embodiment, the positive electrode 101a and the negative electrode 101b (or the negative electrode 101c disposed on both outer sides of the laminate) are disposed, for example, with a separator 104 interposed therebetween, as shown in FIG. However, the present invention is not particularly limited to this arrangement, and the number of layers and the like can be variously changed according to the required capacity and the like.

The positive electrode current collector 105a of each positive electrode 101a is:
Each of the negative electrodes 101 is electrically connected to the positive electrode terminal 3.
The negative electrode current collectors 105 b of b and 101 c are electrically connected to the negative electrode terminal 4. The positive terminal 3 and the negative terminal 4 are
It is attached in a state insulated from the battery case, that is, the top cover 1. The upper lid 1 and the bottom container 2 are welded by melting the upper lid along the entire circumference at a point A shown in an enlarged view in FIG. An electrolyte inlet 5 is opened in the upper lid 1. After the electrolyte is injected, a thermoplastic film 6 having a low moisture permeability represented by an aluminum-modified polypropylene laminate film or an aluminum-modified polyethylene laminate film is formed. And sealed by heat fusion.

In the closing step, it is preferable that the pressure in the battery is lower than the atmospheric pressure. Preferably, it is performed at 86 kPa or less, more preferably at 73 kPa or less. This pressure is determined in consideration of the separator to be used, the type of electrolytic solution, the material, thickness, shape, and the like of the battery container.
When the internal pressure is equal to or higher than the atmospheric pressure, the battery becomes larger than the designed thickness, and the thickness varies greatly, which causes the internal resistance and the capacity of the battery to vary.

The size of the non-aqueous secondary battery shown in FIGS. 1 and 2 is, for example, 300 mm long × 210 mm wide × 6 mm thick.
LiMn ₂ O _{4 for} the positive electrode 101a, the negative electrode 101b,
In the case of a lithium secondary battery using a carbon material for 101c,
For example, it can be used for a power storage system.

The positive electrode active material used for the positive electrode 101a is not particularly limited as long as it is a lithium-based positive electrode material. A lithium composite cobalt oxide, a lithium composite nickel oxide, a lithium composite manganese oxide, or a mixture thereof is used. Further, a system in which one or more different metal elements are added to these composite oxides can be used, and a high-voltage, high-capacity battery can be obtained, which is preferable. When importance is placed on safety, a manganese oxide having a high thermal decomposition temperature is preferable. Examples of the manganese oxide include a lithium composite manganese oxide represented by LiMn ₂ O ₄ , a system in which one or more different metal elements are added to these composite oxides, and an excess of lithium, oxygen, etc. in excess of the stoichiometric ratio. LiMn
₂ O ₄ .

The negative electrode active material used for the negative electrodes 101b and 101c is not particularly limited as long as it is a lithium-based negative electrode material. A material capable of doping and undoping lithium can be used for safety, cycle life, and the like. This is preferable because the reliability of the device is improved. As a material capable of doping and undoping lithium, a graphite-based material, a carbon-based material, a tin oxide-based material, which is used as a negative electrode material of a known lithium ion battery,
Examples thereof include metal oxides such as silicon oxides, and conductive polymers typified by polyacene-based organic semiconductors. In particular, from the viewpoint of safety, a polyacene-based substance that generates a small amount of heat at about 150 ° C. or a material containing the same is desirable.

As the electrolyte of the non-aqueous secondary battery of the present embodiment, a known non-aqueous electrolyte containing a lithium salt can be used. The electrolyte is appropriately determined according to the use conditions such as the positive electrode material, the negative electrode material, and the charging voltage. More specifically, LiPF ₆ , L
Lithium salts such as iBF ₄ and LiClO ₄ are converted into organic solvents such as propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyl lactone, methyl acetate, methyl formate, or a mixed solvent of two or more of these. Examples thereof include those dissolved in a solvent. Further, the concentration of the electrolytic solution is not particularly limited, but is generally set at 0.1.
5 mol / l to 2 mol / l is practical, and it is preferable to use, as a matter of course, an electrolyte having a water content of 100 ppm or less. In addition, the non-aqueous electrolyte used in this specification means a concept including a non-aqueous electrolyte and an organic electrolyte, and also a concept including a gel or solid electrolyte.

Next, the separator 104 will be described in more detail. The configuration of the separator 104 is not particularly limited, but a single-layer or multi-layer separator can be used. At least one of the separators is 15
The thermal shrinkage at 0 ° C. is desirably 5% or less, and more desirably 3% or less, in any direction along the plane. Although the separator depends on the internal structure of the battery, it is generally designed so that the size in the vertical and horizontal directions of the surface is about 1 to 3% longer than that of the positive electrode and the negative electrode for the purpose of preventing internal short circuit. For this reason, when the heat shrinkage exceeds 5%, in a heating state at 150 ° C.,
The separator shrinks to a size smaller than the electrode, which may cause an internal short circuit where the positive electrode and the negative electrode come into direct contact around the separator, or an internal short circuit where the separator is broken due to large shrinkage deformation. This is because of the danger of the occurrence. In addition, this heat shrinkage ratio is set by heating the separator 104 on a hot plate from 25 ° C. to 150 ° C.
Until the temperature of 150 ° C. is maintained for 10 minutes.

Such a low heat shrinkage and high heat resistance
As a material of the separator 104, a cellulosic material, a poly
Ester, polyamide, polyphenylene sulfide
Resin, fluorine-based, polyolefin-based resin, or
Especially limited, such as inorganic fibers such as glass fibers
No, but cellulose, polyester, polyamide
Based, polyphenylene sulfide based and fluorine based trees
Fats and at least one selected from inorganic fibers.
What is included as a part is cost, water content, processing, etc.
From which point of view is desirable. Also, the basis weight of the separator is good.
5g / m ^TwoMore than 30g / m^TwoLess and better
5g / m^TwoMore than 20g / m^TwoIs less than
Preferably 8 g / m^TwoMore than 20g / m^TwoIt is as follows. Sepa
30g / m^TwoIf it exceeds, separate
Thicker battery will increase the battery thickness, or
Is preferable because the porosity decreases and the internal resistance of the battery increases.
5g / m^TwoIf less, practical strength is obtained.
It is not preferable because it cannot be performed.

The non-aqueous secondary battery constructed as described above can be used for home power storage systems (nighttime power storage, cogeneration, solar power generation, etc.), power storage systems for electric vehicles, etc. It can have capacity and high energy density. In this case, the energy capacity is preferably 30 Wh or more, more preferably 50 Wh or more, and the energy density is preferably 180 Wh /
1 or more, more preferably 200 Wh / l. When the energy capacity is less than 30 Wh or when the volume energy density is less than 180 Wh / l, the capacity is small for use in a power storage system, and it is necessary to increase the number of series-parallel batteries in order to obtain a sufficient system capacity. In addition, it is not preferable for a power storage system because a compact design is difficult.

In general, a large lithium secondary battery (energy capacity of 30 Wh or more) for a power storage system can obtain a high energy density, but its battery design is an extension of a small battery for a portable device. Alternatively, the battery has a cylindrical shape, a square shape, or the like having a thickness three times or more that of a small battery for a portable device. In this case, heat easily accumulates inside the battery due to Joule heat generated by the internal resistance of the battery during charge / discharge or internal heat generated by the battery due to a change in entropy of the active material due to the entrance and exit of lithium ions. For this reason, the difference between the temperature inside the battery and the temperature near the battery surface is large, and the internal resistance differs accordingly. As a result, the charge amount and the voltage are likely to vary. Also, since a plurality of batteries of this type are used as assembled batteries, the heat storage easiness varies depending on the installation position of the batteries in the system, causing variations among the batteries, and accurate control of the entire assembled battery. It becomes difficult. Furthermore, the battery temperature rises due to insufficient heat radiation during high-rate charging and discharging, etc., and the battery is put in an unfavorable state. Problems such as induction of reliability and, in particular, safety remain.

The flat non-aqueous secondary battery of the present embodiment has a large heat radiation area and is advantageous for heat radiation, so that the above problems can be solved. That is, the non-aqueous secondary battery of the present embodiment has a flat shape,
Its thickness is preferably less than 12 mm, more preferably less than 10 mm, even more preferably less than 8 mm. The lower limit of the thickness is practically 2 mm or more in consideration of the filling rate of the electrode and the battery size (the smaller the thickness, the larger the area for obtaining the same capacity). Battery thickness is 12
mm or more, it becomes difficult to sufficiently radiate the heat generated inside the battery to the outside, or the temperature difference between the inside of the battery and the vicinity of the battery surface increases, resulting in a difference in internal resistance.
Variations in the amount of charge and voltage in the battery increase. Although the specific thickness is appropriately determined according to the battery capacity and the energy density, it is preferable to design the thickness so as to obtain the expected heat radiation characteristics.

The shape of the non-aqueous secondary battery of the present embodiment is, for example, that the flat front and back surfaces are square, circular,
Various shapes such as an oval shape can be used. In the case of a square shape, the shape is generally a rectangle, but it can also be a polygon such as a triangle or a hexagon. Further, it may be a cylindrical shape such as a thin-walled cylinder. In the case of a cylindrical shape, the thickness of the cylinder is the thickness referred to here. Further, from the viewpoint of ease of production, the flat front and back surfaces of the battery are preferably rectangular, and a notebook-type shape as shown in FIG. 1 is preferable.

The material used for the top cover 1 and the bottom container 2 serving as a battery case is appropriately selected depending on the use and shape of the battery, and is not particularly limited.
Aluminum and the like are common and practical. Also,
The thickness of the battery case is also appropriately determined depending on the use and shape of the battery or the material of the battery case, and is not particularly limited. Preferably, the thickness of the portion of 80% or more of the battery surface area (the thickness of the portion having the largest area constituting the battery case) is 0.2 mm or more. When the thickness is less than 0.2 mm, the strength required for battery production cannot be obtained, which is not desirable.
m or more. Further, it is desirable that the thickness of the portion is 1 mm or less. When the thickness exceeds 1 mm, the force for pressing down the electrode surface increases, but it is not desirable because the internal volume of the battery is reduced and a sufficient capacity cannot be obtained, or the weight increases, which is not desirable. Preferably it is 0.7 mm or less.

As described above, the thickness of the non-aqueous secondary battery is set to 1
By designing it to be less than 2 mm, for example,
When the battery has a large capacity of 0 Wh or more and a high energy density of 180 Wh / l, the battery temperature rise is small even during high-rate charging and discharging, and excellent heat radiation characteristics can be obtained. Therefore, heat storage of the battery due to internal heat generation is reduced, and as a result, thermal runaway of the battery can be suppressed, and a non-aqueous secondary battery excellent in reliability and safety can be provided.

[0028]

The present invention will be described more specifically below with reference to examples of the present invention. (Examples) (1) 100 parts by weight of LiCo 2 O 4, 8 parts by weight of acetylene black, polyvinylidene fluoride (PVDF)
3 parts by weight were mixed with 100 parts by weight of N-methylpyrrolidone (NMP) to obtain a positive electrode mixture slurry. The slurry was applied to both sides of a 20 μm-thick aluminum foil serving as a current collector, dried, and then pressed to obtain a positive electrode. In this embodiment,
The coating area (W1 × W2) of the positive electrode 101a is 262.5
× 192 mm ² , and is applied to both surfaces of a 20 μm current collector 105a with a thickness of 103 μm. As a result, the electrode thickness is 226 μm. Further, on the short side of the electrode, there is an ear portion where the electrode is not applied, and a mounting hole having a diameter of 3 mm is provided.

(2) Graphitized mesocarbon microbeads (MCMB, manufactured by Osaka Gas Chemical Co., Ltd., product number 6-28) 10
0 parts by weight and 10 parts by weight of PVDF were mixed with 90 parts by weight of NMP to obtain a negative electrode mixture slurry. The slurry was applied on both sides of a 14 μm-thick copper foil serving as a current collector, dried, and then pressed to obtain a negative electrode. The application area (W1 × W2) of the negative electrode 101b or 101c is 267 × 195 mm ² . The negative electrode 101b is applied to both surfaces of the 18 μm current collector 105b with a thickness of 108 μm, and as a result, the electrode thickness is 234 μm. On the short side of the electrode, there is an ear portion where the electrode is not applied, and a mounting hole having a diameter of 3 mm is provided. The negative electrode 101c was applied on only one side in the same manner as the negative electrode 101b to form a single-sided electrode having a thickness of 126 μm.

(3) Eight positive electrodes obtained in the above (1),
As shown in FIG. 2, nine negative electrodes (two inner electrodes on one side) were alternately laminated via a separator 104 (TF4030, manufactured by Nippon Advanced Paper Industry Co., Ltd.), which was a cellulosic resin, to form an electrode laminate. The heat shrinkage at 150 ° C. of the separator 104 was 1.0 to 1.1%. The single-sided electrode is disposed on the outermost side as indicated by reference numeral 101c.

(4) The battery bottom container 2 (see FIG. 1)
A SUS304 thin plate of 0.5 mm was drawn to a depth of 5 mm. Also, the top cover 1 of the battery is made of SUS of 0.5 mm thickness.
It was made of 304 thin plate. An aluminum positive electrode terminal and copper negative electrode terminals 3 and 4 (diameter 6 mm) were attached to the upper lid 1. The positive and negative terminals 3 and 4 are insulated from the upper lid 1 by a polypropylene gasket.

(5) Insert the positive electrode terminal 3 into the mounting hole of each positive electrode and the negative electrode terminal 4 into the mounting hole of each negative electrode of the electrode laminate prepared in the above item (3), and connect them with aluminum and copper bolts, respectively. did. Then, the electrode laminate was fixed with an insulating tape, and the corner A in FIG. 1 was laser-welded over the entire circumference. Thereafter, as an electrolyte, a solution in which LiPF6 was dissolved at a concentration of 1 mol / l in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a weight ratio of 1: 1 was injected through an electrolyte injection hole 5 having a diameter of 6 mm. Then, the electrolyte injection hole 5 was sealed with a 0.08 mm-thick aluminum foil-modified polypropylene laminated film punched into a 12 mm diameter by heat fusion under reduced pressure of 40 kPa. (6) The battery obtained as described above is charged up to 4.1 V with a current of 5 A, and thereafter, a constant current constant voltage charge of applying a constant voltage of 4.1 V is performed for 12 hours, followed by a low current of 5 A Discharge to 2.5 V at a discharge capacity of 23.5
Ah, and the energy capacity was 85 Wh. After confirming the capacity, the battery was charged again in the same manner as described above, and the battery was brought to a charged state.
Next, in order to confirm safety, a heating test up to 150 ° C. was performed according to UL1642. Battery surface temperature is 150 ° C
Even above, there was no drop in battery voltage, and the heat resistance and safety were good.

Comparative Example A battery was manufactured in the same manner as in the above example, except that a separator made of polyethylene resin (N710, manufactured by Asahi Kasei Kogyo) was used instead of the separator used in the above example. The battery was operated at a current of 5 A in 4.1.
V, then a constant current constant voltage charge of applying a constant voltage of 4.1 V was performed for 12 hours, followed by discharging at a low current of 5 A to 2.5 V. The discharge capacity was 23.4 Ah.
And the energy capacity was 84 Wh. After confirming the capacity, the battery was charged again in the same manner as described above, and the battery was brought to a charged state. Next, in order to confirm safety, a heating test up to 150 ° C was conducted in UL.
Performed according to 1642. When the battery surface temperature became 130 ° C. or higher, the test was stopped because the battery voltage sharply dropped and the battery surface temperature rose to the heating atmosphere temperature or higher. After the test, an internal short circuit due to contraction of the separator was confirmed.

[0034]

As is apparent from the above description, according to the present invention, in a flat battery, particularly a flat battery having a large capacity and a high volume energy density, a separator having a small heat shrinkage even under a high temperature environment. By using, it is possible to provide a highly safe non-aqueous secondary battery having excellent heat resistance and capable of preventing internal short circuit.

[Brief description of the drawings]

FIG. 1 is a plan view and a side view of a non-aqueous secondary battery for a power storage system according to an embodiment of the present invention.

FIG. 2 is a side view showing a configuration of an electrode laminate housed inside the battery shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top cover 2 Bottom container 3 Positive electrode terminal 4 Negative electrode terminal 5 Injection port 6 Sealing film 101a Positive electrode (both sides) 101b Negative electrode (both sides) 101c Negative electrode (one side) 104 Separator 105a Positive electrode collector 105b Negative electrode collector

Continuation of the front page (72) Inventor Haruo Kikuta 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka Gas Co., Ltd. (Reference) 5H011 AA02 CC06 DD03 FF03 GG09 HH02 HH13 KK01 5H021 AA01 CC01 EE07 EE08 EE10 EE11 EE21 EE28 HH00 HH01 HH06 5H029 AJ12 AK03 AL02 AL06 AL07 AL16 AM02 AM03 AM04 AM05 AM07 BJ04 BJ12 DJ02 DJ04 EJ01 EJ03 EJ06 EJ12 HJ00 HJ04 HJ16 HJ19

Claims (6)

[Claims] 1. A flat non-aqueous secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt, wherein the energy capacity is 30 Wh or more and the volume energy density is 180 Wh / l or more. A non-aqueous separator, wherein at least one of the separators has a heat shrinkage at 150 ° C. of 5% or less in any direction along the surface. Rechargeable battery. 2. The non-aqueous secondary battery according to claim 1, wherein the positive electrode, the negative electrode, and the separator are housed in a battery case, and the shape of the front and back surfaces of the battery case is rectangular. . 3. The non-aqueous secondary battery according to claim 1, wherein the battery container has a flat shape with a thickness of less than 12 mm. 4. The non-aqueous secondary battery according to claim 1, wherein the thickness of the battery container is 0.2 mm or more and 1 mm or less. 5. The separator according to claim 1, wherein the separator contains at least one selected from the group consisting of cellulose, polyester, polyamide, polyphenylene sulfide and fluorine resins, and inorganic fibers.
The non-aqueous secondary battery according to any one of the above. 6. The basis weight of the separator is 5 g / m.
^The weight is ² g / m ² or more and 30 g / m ² or less.
6. The non-aqueous secondary battery according to any one of 1. to 5.