JP2016081757A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery superior in high-rate cycle characteristic, in which the outflow of a nonaqueous electrolyte from a negative electrode active material layer is suppressed at a high level.SOLUTION: A nonaqueous electrolyte secondary battery is provided according to the present invention, which comprises a wound electrode body. The wound electrode body is arranged by: putting together a positive electrode sheet 10 including an elongated positive electrode current collector 12 and a positive electrode active material layer 14 on a surface of the elongated positive electrode current collector, and a negative electrode sheet 20 including an elongated negative electrode current collector 22 and a negative electrode active material layer 24 on a surface of the elongated negative electrode current collector through an elongated separator sheet 40 so that the positive electrode active material layer 14 is opposed to the negative electrode active material layer 24; and winding them in a lengthwise direction. The negative electrode active material layer 24 includes graphite-based particles 26. With the negative electrode active material layer 24, the ratio (I/I) of a peak intensity Iof (110)-plane to a peak intensity Iof (004)-plane based on X-ray crystal structure analysis is 0.061 or larger. The negative electrode active material layer 24 and the separator sheet 40 are glued to each other with a bonding strength of 59 mN/cm or larger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a non-aqueous electrolyte secondary battery. Specifically, the present invention relates to a nonaqueous electrolyte secondary battery provided with a wound electrode body.

In nonaqueous electrolyte secondary batteries such as lithium ion secondary batteries, graphite-based materials (graphite-based particles) are frequently used as negative electrode active materials. However, graphite-based particles have a property that the (002) plane is easily oriented in parallel to the surface of the current collector when the negative electrode active material layer is formed on the surface of the current collector by a so-called paste coating method. As a result, the non-aqueous electrolyte flows out of the negative electrode (and thus out of the electrode body) with the expansion and contraction of the graphite-based particles during charge / discharge of the battery, and the internal resistance may increase during high-rate charge / discharge, for example. is there.
As a technology related to this, for example, Patent Document 1 discloses a lithium ion secondary battery including a wound electrode body, in the negative electrode at both end portions in the width direction orthogonal to the winding axis direction of the wound electrode body. A lithium ion secondary battery in which the degree of perpendicularity of the negative electrode active material (graphite particles) is 1 or more is disclosed.

JP 2013-069579 A JP 2003-151638 A JP 2003-197189 A

In the wound electrode body, the inflow / outflow of the nonaqueous electrolyte is generally limited to the end portion (side surface portion) in the width direction. For this reason, according to the structure of patent document 1, it can suppress effectively that a non-aqueous electrolyte flows out from the both ends (cross section of a negative electrode active material layer) of the said width direction, and what is called a wound electrode body. It is possible to prevent liquid drainage from occurring.
However, according to the study by the present inventors, there is room for further improvement in the above technique. Specifically, for example, if the perpendicularity of the graphite particles is low in the center portion in the width direction, the nonaqueous electrolyte tends to flow in the width direction. For this reason, a concentration distribution (concentration unevenness) of the supporting salt may occur in the width direction of the wound electrode body. Further, when there is a gap at the interface between the negative electrode and the separator, the nonaqueous electrolyte may flow out from there.

  The present invention has been made in view of such circumstances, and an object thereof is a non-aqueous electrolyte secondary battery including a wound electrode body, and the outflow of the non-aqueous electrolyte from the negative electrode active material layer is highly suppressed. Another object of the present invention is to provide a non-aqueous electrolyte secondary battery excellent in high rate cycle characteristics.

The inventors have repeatedly studied to achieve the above object. As a result, the inventors arrived at controlling the flow of the nonaqueous electrolyte in the negative electrode active material layer (adjusting the flow direction of the nonaqueous electrolyte). And further diligent examination was carried out and it came to complete this invention.
According to the present invention, a positive electrode sheet having a positive electrode active material layer on the surface of a long positive electrode current collector, and a negative electrode sheet having a negative electrode active material layer on the surface of a long negative electrode current collector, Provided is a non-aqueous electrolyte secondary battery including a wound electrode body that is wound with a long separator sheet so that the material layer and the negative electrode active material layer face each other and wound in the longitudinal direction. . The negative electrode active material layer contains graphite-based particles. The ratio of the peak intensity _{I 004} of the negative electrode active material layer (110) plane and the peak intensity _{I 110} (004) plane _(I 110 _{/ I 004)} is 0.061 or more. The negative electrode active material layer and the separator sheet are bonded with an adhesive strength of 59 mN / cm or more.

By satisfying the orientation strength ratio, the basal surface of the graphite-based particles can be oriented perpendicularly to the thickness direction of the negative electrode active material layer (parallel to the width direction of the negative electrode active material layer). As a result, the non-aqueous electrolyte can easily move in the thickness direction of the negative electrode active material layer, and input / output characteristics can be improved. Moreover, the movement of the nonaqueous electrolyte in the width direction of the wound electrode body can be suppressed. However, in such a configuration, the nonaqueous electrolyte is easily pushed out from the interface between the negative electrode active material layer and the separator. For this reason, by adhering the negative electrode active material layer and the separator to close the gap, it is possible to highly prevent the nonaqueous electrolyte from flowing out.
In other words, according to the configuration disclosed herein, it is possible to realize a non-aqueous electrolyte secondary battery that is highly resistant to liquid withering and unevenness in salt concentration in the negative electrode active material layer and that has excellent high-rate cycle characteristics.

In the present specification, “graphite-based particles” are particles composed solely of graphite, and particles occupying 50% by mass or more (typically 80% by mass or more, for example, 90% by mass or more) of the entire material. Is a general term.
Further, the orientation strength ratio (I ₁₁₀ / I ₀₀₄ ) of the negative electrode active material layer can be obtained from X-ray diffraction measurement (XRD: X-ray diffraction) using CuKα rays. Specifically, first, a negative electrode sheet having a negative electrode active material layer to be measured is cut out. Next, XRD measurement is performed on the negative electrode sheet, and a diffraction peak intensity I ₁₁₀ on the ( ₁₁₀ ) plane and a diffraction peak intensity I _{004 on} the (004) plane are obtained from the obtained XRD chart. The orientation intensity ratio (I ₁₁₀ / I ₀₀₄ ) can be calculated by dividing I ₁₁₀ by I ₀₀₄ .
Further, the bonding strength between the negative electrode active material layer and the separator sheet can be measured by a 180 ° peel test defined in JIS-K6854-2 (1999). Specifically, first, a combination of a negative electrode and a separator to be measured is prepared. Next, the separator side is mounted (fixed) on a mounting table with a double-sided adhesive tape. Next, the negative electrode active material layer side is fixed to a double-sided pressure-sensitive adhesive tape attached to a tension jig. And it can measure by raising a tension jig to a perpendicular direction and pulling with the peeling angle of 180 degree | times.

  Patent Document 2 discloses a lithium ion secondary battery including an adhesive resin layer between a positive electrode or a negative electrode and a separator. Patent Document 3 discloses a negative electrode for a lithium secondary battery in which a paste containing graphite powder is applied to a current collector and then the 002 surfaces of graphite particles contained in the graphite powder are oriented in the same direction in a magnetic field. A manufacturing method is disclosed.

It is a schematic diagram which shows the partial cross-section of the wound electrode body which concerns on one Embodiment. It is a structure of an evaluation battery and an evaluation result of battery characteristics. It is a graph which shows typically the evaluation method of an input test, (a) has shown relation between voltage (V) at the time of charge, and time (T), (b) is charging time (second) and electric power ( W). It is a graph which shows the charge / discharge pattern of 1 cycle in a high-rate cycle test.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. Note that matters other than matters specifically mentioned in the present specification and necessary for carrying out the present invention (for example, general manufacturing processes of components and batteries not characterizing the present invention) It can be grasped as a design matter of those skilled in the art based on the prior art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. Moreover, in the following drawings, the same code | symbol is attached | subjected to the member and site | part which show | plays the same effect | action, and the overlapping description may be abbreviate | omitted or simplified. The dimensional relationship (length, width, thickness, etc.) in each figure does not necessarily reflect the actual dimensional relationship.

  The non-aqueous electrolyte secondary battery disclosed herein includes a wound electrode body and a non-aqueous electrolyte. Hereinafter, each component will be described in order.

The wound electrode body of the non-aqueous electrolyte secondary battery disclosed herein has a long positive electrode sheet and a long negative electrode sheet stacked on each other via a long separator sheet and wound in the long direction. It is configured to turn. In a preferred aspect, the wound electrode body has a flat appearance. In other words, the cross section orthogonal to the winding axis has a substantially rounded rectangular shape.
FIG. 1 is a schematic diagram showing a partial cross-sectional structure of a wound electrode body according to an embodiment. As shown in FIG. 1, the positive electrode sheet 10 and the negative electrode sheet 20 are arranged so that the positive electrode active material layer 14 and the negative electrode active material layer 24 face each other with the separator sheet 40 interposed therebetween.

The positive electrode sheet 10 includes a long positive electrode current collector 12 and a positive electrode active material layer 14 formed on the surface thereof. As the positive electrode current collector 12, a conductive member made of a metal having good conductivity (for example, aluminum, nickel, etc.) can be suitably used.
The positive electrode active material layer 14 is formed on the surface of the positive electrode current collector 12 in a band shape with a predetermined width along the longitudinal direction. The positive electrode active material layer 14 includes at least a positive electrode active material. Typically, it further contains a conductive material and a binder. Examples of the positive electrode active material include LiNiO ₂ , LiCoO ₂ , LiFeO ₂ , LiMn ₂ O ₄ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.5 Mn _1.5 O ₄ , LiFePO _4. Examples thereof include lithium composite metal oxides. Of these, a lithium nickel cobalt manganese composite oxide having a layered structure is preferable from the viewpoint of thermal stability and energy density. Examples of the conductive material include carbon materials such as carbon black (for example, acetylene black and ketjen black), activated carbon, and graphite. Examples of the binder include a vinyl halide resin such as polyvinylidene fluoride (PVdF) and a polyalkylene oxide such as polyethylene oxide (PEO).

The negative electrode sheet 20 includes a long negative electrode current collector 22 and a negative electrode active material layer 24 formed on the surface thereof. As the negative electrode current collector 22, a conductive material made of a metal having good conductivity (for example, copper, nickel, etc.) can be suitably used.
The negative electrode active material layer 24 is formed on the surface of the negative electrode current collector 22 in a band shape wider than the positive electrode active material layer 14 along the longitudinal direction. The negative electrode active material layer 24 includes at least graphite particles 26. Typically, it further contains a thickener and a binder. Examples of the graphite-based particles 26 include graphite-based carbon materials such as natural graphite, artificial graphite, and amorphous carbon-coated graphite (forms in which amorphous carbon is coated on the surface of graphite particles). The average particle size of the graphite-based particles 26 (particle size corresponding to 50% cumulative volume based on laser diffraction / light scattering method; the same applies hereinafter) achieves both high energy density and high input / output density at a high level. From a viewpoint, about 1-30 micrometers is preferable. Moreover, the graphite-type particle | grains 26 can have shape anisotropy, for example, can be shapes, such as scale shape and flat plate shape. Examples of the thickener include celluloses such as carboxymethyl cellulose (CMC) and methyl cellulose (MC). Examples of the binder include rubbers such as styrene butadiene rubber (SBR) and vinyl halide resins such as polyvinylidene fluoride (PVdF).

In the negative electrode sheet 20, the basal surface of the graphite-based particles 26 is oriented perpendicular to the thickness direction of the negative electrode active material layer 24 (parallel to the width direction of the wound electrode body). In other words, the orientation strength ratio (I ₁₁₀ / I ₀₀₄ ) based on XRD of the negative electrode active material layer 24 is 0.061 or more, for example, 0.061 to 0.099, typically 0.065 or more, Preferably it is 0.065-0.095. As a result, the nonaqueous electrolyte can easily move in the thickness direction of the negative electrode active material layer 24, and input / output characteristics can be improved. Moreover, the movement of the nonaqueous electrolyte in the width direction can be suppressed, and the occurrence of uneven salt concentration can be prevented.
The electrode density of the negative electrode active material layer 24 is, for example, 0.8 to 1.4 g / cm ³ (typically 1.0 to 1.4 g / cm ³ , preferably 1.2 to 1.4 g / cm ³ ). It is good to do. By setting it as the said electrode density, a moderate space | gap can be maintained in an active material layer, and the more excellent input-output characteristic can be implement | achieved. In addition, there is also an effect that the above-described orientation strength ratio can be stably realized.

  A long separator sheet 40 is disposed between the positive electrode active material layer 14 and the negative electrode active material layer 24. Examples of the separator sheet 40 include a porous resin sheet (film) made of a resin such as polyethylene (PE), polypropylene (PP), polyester, cellulose, and polyamide. Among these, polyolefin-based porous resin sheets (for example, PE and PP) are preferable.

In the wound electrode body of the nonaqueous electrolyte secondary battery disclosed herein, the negative electrode active material layer 24 and the separator sheet 40 are physically bonded (integrated). In other words, the adhesive strength at the interface between the negative electrode active material layer 24 and the separator sheet 40 is 59 mN / cm or more, typically 70 mN / cm or more, for example, 101 mN / cm or more. When the orientation strength ratio is satisfied, the nonaqueous electrolyte tends to easily flow out from the interface between the negative electrode active material layer 24 and the separator sheet 40 as a contradiction that the nonaqueous electrolyte easily moves in the thickness direction of the negative electrode active material layer 24. is there. Therefore, by integrating the negative electrode active material layer 24 and the separator sheet 40 with the above adhesive strength, for example, the battery generates heat during high-rate charge / discharge and the nonaqueous electrolyte expands in volume, or the graphite particles 26 expand. Thus, even when the negative electrode active material layer 24 is greatly expanded in the stacking direction (the direction facing the positive electrode active material layer 14), the non-aqueous electrolyte is highly prevented from flowing out of the negative electrode active material layer 24. can do. As a result, it is possible to realize a battery with excellent high-rate cycle characteristics in which battery resistance hardly increases even when high-rate charge / discharge is repeated.
Although the upper limit value of the adhesive strength is not particularly limited, it is, for example, 151 mN / cm or less, preferably 144 mN / cm or less, more preferably 135 mN / cm or less from the viewpoint of stably exhibiting the effects of the present invention at a high level. Good.

  Such a wound electrode body is prepared, for example, by (1) preparing a negative electrode paste containing graphite-based particles 26; (2) applying the negative electrode paste to the surface of the long negative electrode current collector 12 in a strip shape. (3) Before the applied negative electrode paste dries, the graphite particles 26 are magnetically oriented; (4) The negative electrode sheet is dried and pressed; (5) The above prepared negative electrode sheet 20 and separately The prepared positive electrode sheet 10 is overlapped with a long separator sheet 40 and wound in the longitudinal direction to produce a wound body; (6) The wound body is heated to a predetermined temperature (for example, 60). In a state where the temperature is raised to ℃ or higher, 60 to 80 ℃ in one preferred example, a load (for example, 3000 kgf or more, 4,000 to 10,000 kgf in one preferred example) is applied from one direction to form a flat shape. object It can be prepared by; that the binder component contained in the layer by penetrating into the pores of the separator to bond the negative electrode active material layer and the separator sheet. The general manufacturing process of the battery may be the same as the conventional one. Further, the orientation of the graphite-based particles by magnetic force can be performed according to, for example, JP-A-2013-069579.

The nonaqueous electrolyte typically includes a nonaqueous solvent and a supporting salt. Examples of the supporting salt include lithium salt, sodium salt, magnesium salt and the like. Of these, lithium salts such as LiPF ₆ and LiBF ₄ are preferable. Examples of the non-aqueous solvent include aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones, and lactones. Of these, carbonates such as ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) are preferable.

  Although the nonaqueous electrolyte secondary battery disclosed here can be used for various applications, a high energy density and a high capacity can be realized by providing a wound electrode body. Further, since the configuration of the wound electrode body has the above-described configuration, the input / output characteristics and the high rate cycle characteristics can be compatible at a high level as compared with the conventional product. Therefore, taking advantage of this feature, for example, it can be suitably used as a power source (drive power source) of a hybrid vehicle or an electric vehicle.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples.

[Construction of non-aqueous electrolyte secondary battery]
First, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ particles (NCM, average particle size 5 μm) as a positive electrode active material, acetylene black (AB) as a conductive material, and polyvinylidene fluoride (Binder as a binder) PVdF) was weighed so that the solid content ratio was NCM: AB: PVdF = 92: 5: 3 and mixed with N-methylpyrrolidone (NMP) to prepare a positive electrode paste. This paste was applied to both sides of a long aluminum foil (positive electrode current collector) having an average thickness of 15 μm in a strip shape having a width of 100 mm, dried and pressed to obtain a long positive electrode sheet.
Next, graphite particles (C, average particle size 10 μm) as a negative electrode active material, styrene butadiene rubber (SBR) as a binder, and carboxymethyl cellulose (CMC) as a thickener have a solid content ratio of C: A negative electrode paste was prepared by weighing so that SBR: CMC = 98: 1: 1 and mixing with ion-exchanged water. The paste was applied in a strip shape with a width of 105 mm on both sides of a long copper foil (negative electrode current collector) having an average thickness of 10 μm, and the graphite particles were oriented by magnetic force. By drying and pressing this, a long negative electrode sheet provided with a negative electrode active material layer having an electrode density and an orientation strength ratio shown in FIG. 2 was obtained. In addition, about orientation strength ratio, the XRD measurement using a CuK (alpha) ray was performed in arbitrary three places of a negative electrode active material layer, and the arithmetic mean value was employ | adopted.

The positive electrode sheet and the negative electrode sheet were overlapped in the longitudinal direction via a separator sheet and wound into a cylindrical shape. As the separator sheet, a PP / PE / PP three-layer structure (average thickness 24 μm) in which polypropylene (PP) is laminated on both sides of polyethylene (PE) was used. Next, the cylindrical wound body was formed into a flat shape under the brazing conditions (temperature and load) shown in FIG. 2, and at the same time, the negative electrode active material layer and the separator sheet were bonded. The current collector plates were welded to both ends of the flat wound electrode body, and then accommodated in a rectangular parallelepiped battery case, and the lid plate and the battery case were welded. And the nonaqueous electrolyte was inject | poured from the injection hole provided in the cover plate. As the non-aqueous electrolyte, a mixed salt containing ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a volume ratio of EC: DMC: EMC = 3: 3: 4 is used as a supporting salt. As a solution, LiPF ₆ dissolved at a concentration of 1 mol / L was used. Finally, the liquid injection hole was tightened with a sealing screw, and non-aqueous electrolyte secondary batteries (Examples 1 to 15 and Comparative Examples 1 to 7, battery design capacity: 5 Ah) having the configuration shown in FIG. 2 were constructed.

[Measurement of initial characteristics]
Under an environment of 25 ° C., constant current charge (CC charge) at 0.2 C until the battery voltage becomes 4.1 V, then constant current discharge (CC discharge) at 0.2 C to 3.0 V, and the initial capacity is confirmed. Further, the battery was adjusted to a SOC of 60%, discharged at a discharge rate of 20 C for 10 seconds, and the initial IV resistance was calculated by dividing the voltage drop at this time by the current value.

[Input test]
Under the environment of 25 ° C., the battery is adjusted to a state of SOC 60%, and constant power charging is performed at different power rates A, B, and C, so that the time X, Y, and the time until the battery voltage reaches 4.1 V, respectively. Z (seconds) was measured (see FIG. 3A). Then, the 10-second input was calculated from the slope of the first-order approximation line of the required charging time (seconds) -power (W) plot (see FIG. 3B). The results are shown in the corresponding column of FIG. FIG. 2 shows relative values when the 10-second input in Example 1 is set to 100. It can be said that the larger the numerical value, the higher the input density.

[High rate cycle test]
The charge / discharge cycle shown in FIG. 4 was regarded as one cycle, and 2000 cycles were charged / discharged, and the IV resistance was measured in the same manner as described above every 100 cycles. Then, from the initial IV resistance and the IV resistance after 2000 cycles, resistance is increased by the following formula: resistance increase rate (%) = (IV resistance after 2000 cycles−initial IV resistance) / initial IV resistance × 100; The increase rate (%) was calculated. The results are shown in the corresponding column of FIG. FIG. 2 shows relative values when the resistance increase rate of Example 1 is set to 100. The smaller this value, the better the battery with high rate cycle characteristics.

  As shown in FIG. 2, in Comparative Example 2, the magnetic field orientation was performed on the negative electrode active material layer to increase the orientation strength. As a result, the input characteristics were improved as compared with Comparative Example 1 (conventional product). In Comparative Example 3, the temperature and load were increased when the wound body was formed into a flat shape (at the time of brazing). As a result, the input characteristics and the high rate cycle characteristics were slightly higher than those of Comparative Example 1 (conventional product). Declined. Thus, in Comparative Examples 2 and 3, it was difficult to achieve both high input characteristics and excellent high rate cycle characteristics.

In Comparative Examples 4 and 5 and Examples 1 to 3, the brazing conditions were the same as those in Comparative Example 3, and the magnetic strength during magnetic field orientation was adjusted to change the orientation strength of the negative electrode active material layer.
As a result, by increasing the orientation strength to 0.065 or more, the resistance increase rate could be reduced by 20% or more compared to Comparative Example 1. In addition, the input characteristics improved as the orientation strength increased. In Examples 1 to 3, the input characteristics and the high rate cycle characteristics were compatible at a high level.

In Comparative Examples 6 and 7 and Examples 4 to 13, the orientation strength of the negative electrode active material layer was the same as that of Comparative Example 2, and the adhesive strength was changed by adjusting the temperature and load during brazing.
As a result, by increasing the adhesive strength to 59 mN / cm or more (preferably 70 mN / cm or more), the resistance increase rate could be reduced by about 20% or more compared to Comparative Example 1. Also, since the adhesive strength exceeds 115 mN / cm, the input characteristics gradually decrease as the adhesive strength increases, and the resistance increase rate after the high rate cycle tends to increase. This is presumably because the coverage of the negative electrode surface (reaction surface) by the separator increased as the adhesive strength between the negative electrode and the separator increased. That is, it is presumed that the effect of improving the input by the magnetic field orientation is reduced, the reaction at the high rate charge / discharge is insufficient, and the outflow of the nonaqueous electrolyte cannot be sufficiently suppressed. From this, the adhesive strength was 151 mN / cm or less (preferably 144 mN / cm or less, more preferably 135 mN / cm or less), and the effects of the present invention could be stably achieved at a higher level.

In Examples 14 and 15, the negative electrode pressing conditions were adjusted to change the electrode density. As a result, at least in the range of the electrode density of 1.0 to 1.4 g / cm ³ , the fluidity of the nonaqueous electrolyte and the permeability of lithium ions are well maintained, and the effects of the present invention can be stably achieved. I was able to play.

  As is clear from these evaluation results, according to the technique disclosed herein, a nonaqueous electrolyte secondary battery excellent in battery characteristics (particularly, input characteristics and high rate cycle characteristics) can be provided.

  As mentioned above, although this invention was demonstrated in detail, the said embodiment and Example are only illustrations and what changed and changed the above-mentioned specific example is contained in the invention disclosed here.

DESCRIPTION OF SYMBOLS 10 Positive electrode sheet 12 Positive electrode collector 14 Positive electrode active material layer 20 Negative electrode sheet 22 Negative electrode collector 24 Negative electrode active material layer 26 Graphite-based particle 40 Separator sheet

Claims (1)

A positive electrode sheet having a positive electrode active material layer on the surface of a long positive electrode current collector, and a negative electrode sheet having a negative electrode active material layer on the surface of a long negative electrode current collector, the positive electrode active material layer and the A non-aqueous electrolyte secondary battery comprising a wound electrode body that is stacked through a long separator sheet so as to face the negative electrode active material layer and wound in the longitudinal direction,
The negative electrode active material layer includes at least graphite-based particles,
The ratio (I ₁₁₀ / I ₀₀₄ ) between the peak intensity I ₁₁₀ of the ( ₁₁₀ ) plane and the peak intensity I ₀₀₄ of the (004) plane based on the X-ray crystal structure analysis of the negative electrode active material layer is 0.061 or more,
The non-aqueous electrolyte secondary battery in which the negative electrode active material layer and the separator sheet are bonded with an adhesive strength of 59 mN / cm or more.

Images