JP2013196798A - Nonaqueous electrolyte secondary battery and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a nonaqueous electrolyte secondary battery achieving increased density of a mixture layer by securing a required gas generation amount while decreasing an additive amount of an overcharge additive, thereby capable of achieving increased capacity; and a method for manufacturing the nonaqueous electrolyte secondary battery.SOLUTION: A nonaqueous electrolyte secondary battery includes a pressure-type current interrupt mechanism and an overcharge additive. In the nonaqueous electrolyte secondary battery, the density of a mixture layer 12 in a positive electrode is 2.6 g/cmor more, the air resistance of the mixture layer 12 is 250 sec/100 mL or less, and the horizontal electronic resistance of the mixture layer 12 is 8.5 Ω cm or less.

Description

  The present invention relates to a technique for a nonaqueous electrolyte secondary battery and a method for manufacturing the same, and more particularly to a technique for increasing the capacity of a nonaqueous electrolyte secondary battery.

In recent years, with the spread of hybrid vehicles, electric vehicles, etc., there is an increasing need for technologies for further increasing the capacity of non-aqueous electrolyte secondary batteries (particularly lithium ion secondary batteries) used for these.
In order to increase the capacity of the nonaqueous electrolyte secondary battery, it is effective to increase the density of the active material layer (hereinafter referred to as a composite layer) in the positive electrode constituting the nonaqueous electrolyte secondary battery. It is known that

  In addition, in a non-aqueous electrolyte secondary battery having a positive electrode with a higher density of the composite material layer, the need to reliably prevent overcharge increases as the capacity of the non-aqueous electrolyte secondary battery increases. A configuration including a current interrupt mechanism (also called CID: Current Interrupt Device) that is a mechanism for preventing charging is generally employed.

  And in a nonaqueous electrolyte secondary battery provided with such a current interruption mechanism, a substance that serves as a gas generation source for operating the current interruption mechanism on the electrolyte solution or electrode mixture layer enclosed in the secondary battery ( Hereinafter referred to as overcharge additive). As overcharge additives, BP (biphenyl), CHB (phenylcyclohexane) and the like are generally used.

As a technique relating to a nonaqueous electrolyte secondary battery that includes a current interruption mechanism and in which an overcharge additive is added to an electrolyte solution or an electrode mixture layer, for example, a technique disclosed in Patent Document 1 below is provided. It is publicly known.
In the prior art according to Patent Document 1, when a lithium ion secondary battery as an example of a nonaqueous electrolyte secondary battery is overcharged, gas is generated starting from the decomposition reaction of the overcharge additive, By raising the pressure, the current interruption mechanism (sealing plate) is actuated (broken) to interrupt the current. In the following, such a type of current interruption mechanism that is activated by the pressure increase inside the secondary battery is referred to as a “pressure type” current interruption mechanism.

JP 2006-324235 A

  In a non-aqueous electrolyte secondary battery equipped with a pressure-type current interruption mechanism that uses a gas generated by an overcharge additive as an operating source, a predetermined gas generation amount corresponding to the operating pressure (mechanical characteristics) of the current interruption mechanism is obtained. It is necessary to secure.

As a method for securing a predetermined gas generation amount, for example, a current interruption mechanism with a low operating pressure is adopted, or a current gap is reduced with a smaller gas generation amount, such as reducing the void amount inside the battery. There is a method of operating the mechanism.
In such a method, the amount of electrolyte retained in the composite layer (that is, the porosity of the composite layer) can be lowered, so that the density of the composite layer can be increased. The amount of charging additive added can also be reduced.
However, in such a method, another problem arises that the current interruption mechanism is likely to malfunction due to an increase in internal pressure accompanying an increase in battery temperature.

  As another method for ensuring a predetermined gas generation amount, the amount of overcharge additive added is increased, or the porosity of the composite layer is increased (that is, the density of the composite layer is decreased). There is a method for increasing the gas generation amount by increasing the reactivity of the overcharge additive.

However, increasing the porosity of the composite material layer is directly linked to reducing the density of the composite material layer, which is against the increase in capacity of the nonaqueous electrolyte secondary battery.
In addition, even if the amount of overcharge additive added is increased, a predetermined amount of gas generated can be secured in a short time in a state where the porosity of the composite layer is small and the reactivity of the overcharge additive is low. Therefore, it is not possible to ensure the function as a current interruption mechanism (cut off the current in a short time during overcharge).

That is, the problems of increasing the density of the composite layer and increasing the amount of gas generated are in a trade-off relationship, and it has been difficult to increase the capacity of non-aqueous electrolyte secondary batteries.
For this reason, in order to increase the capacity of non-aqueous electrolyte secondary batteries, it is desired to develop a technology that can secure the required gas generation amount while suppressing the amount of overcharge additive added as much as possible. there were.

  The present invention has been made in view of such a current problem, ensuring a necessary gas generation amount while suppressing the addition amount of the overcharge additive, increasing the density of the composite layer, and increasing the capacity. An object of the present invention is to provide a nonaqueous electrolyte secondary battery capable of achieving the above and a method for manufacturing the same.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1, there is provided a nonaqueous electrolyte secondary battery comprising a pressure type current interruption mechanism and an overcharge additive, wherein the density of the composite layer in the positive electrode is 2.6 g / cm ³ or more. The air permeability resistance of the composite material layer is 250 sec / 100 mL or less, and the horizontal electronic resistance of the composite material layer is 8.5 Ω · cm or less.

In Claim 2, It is a manufacturing method of the nonaqueous electrolyte secondary battery of Claim 1, Comprising: In the process of pressing the said composite material layer in the manufacturing process of the member which comprises the said positive electrode, The compression rate is 37.5% or less, and the composite material layer is pressed a plurality of times, so that the density of the composite material layer is 2.6 g / cm ³ or more.

In Claim 3, It is a manufacturing method of the nonaqueous electrolyte secondary battery of Claim 1, Comprising: In the manufacturing process of the paste for producing | generating the said composite material layer in the manufacturing process of the member which comprises the said positive electrode, The viscosity at the time of kneading the paste is set to 15000 mPa · sec or more in a region where the shear rate is 0.2 sec ⁻¹ .

  As effects of the present invention, the following effects can be obtained.

  In claim 1, in the non-aqueous electrolyte secondary battery having a high-density positive electrode, it is possible to ensure the amount of gas generation necessary for operating the current interruption mechanism, and to add the amount of overcharge additive Can be suppressed.

  According to the second aspect of the present invention, a positive electrode material having a low air resistance can be reliably manufactured.

  According to the third aspect of the present invention, a positive electrode material having a low air resistance can be reliably manufactured.

The perspective schematic diagram which shows the measuring method of the air permeability resistance with respect to a free film. The perspective schematic diagram which shows the measuring method of the horizontal electronic resistance with respect to a compound-material layer. The figure which shows the relationship between the permeation | transmission resistance in the material for positive electrodes whose density of a compound material layer is 2.8 g / cm < ³ >, and the amount of gas generation at the time of an overcharge. The flowchart which shows the flow of the manufacturing process of the material for positive electrodes. The figure which shows the measurement result of the permeation | transmission resistance, horizontal electronic resistance, and gas generation amount when the press conditions are changed in the positive electrode material whose density of the composite layer is 2.9 g / cm ³ . The figure which shows the relationship between the permeation | transmission resistance and the migration index | exponent in the positive electrode material whose density of a compound material layer is 2.8 g / cm < ³ >. The figure which shows the relationship between the migration index | exponent in positive electrode material, and the viscosity (area | region of shear rate 0.2sec- ¹ ) of the paste for producing | generating positive electrode material.

Next, embodiments of the invention will be described.
A nonaqueous electrolyte secondary battery (for example, a lithium ion secondary battery) according to an embodiment of the present invention is configured to include a positive electrode having a high-density composite material layer and a current interruption mechanism.
In the present embodiment, what is called a “high density” composite material layer is limited to a density of 2.6 g / cm ³ or more.
This is because, in a nonaqueous electrolyte secondary battery having a positive electrode having a density of the composite layer of less than 2.6 g / cm ³ , A) densification of the composite layer in the positive electrode and B) overcharge addition in the positive electrode This is because the problem of ensuring the amount of gas generated by the agent does not occur, and it is considered that the necessity of providing a current interruption mechanism (CID) is scarce.

  And in the nonaqueous electrolyte secondary battery shown in the present embodiment, there is a trade-off relationship, A) densification of the mixture layer in the positive electrode, and B) securing the amount of gas generated by the overcharge additive in the positive electrode, Therefore, it is possible to increase the electric capacity of the nonaqueous electrolyte secondary battery.

  More specifically, the nonaqueous electrolyte secondary battery shown in this embodiment is characterized by a member constituting the positive electrode (hereinafter referred to as a positive electrode member). 1) Permeation of the composite layer in the positive electrode It is characterized in that the resistance is controlled so that 2) the horizontal electronic resistance of the composite layer in the positive electrode is not more than a predetermined threshold value.

  Here, 1) A method for measuring the transmission resistance of the composite layer in the positive electrode will be described with reference to FIG. 1 and FIG.

In order to measure the permeation resistance of the composite layer in the positive electrode, first, the member 15 (in which only the composite layer 12 is used) in a mode in which the current collector foil 11 is removed from the positive electrode material 10 (see FIG. 2). Hereinafter, it is referred to as a free film 15).
And since such a free film 15 is a porous material with air permeability, it is possible to measure the permeation resistance.

The measurement of the transmission resistance of the free film 15 is performed using a predetermined measuring device (so-called densometer) in accordance with the JISP8117 standard (Gurley method).
More specifically, as shown in FIG. 1, the lower end of a cylindrical portion 20 having an inner diameter of 28.6 mm arranged with its axis oriented in the vertical direction is closed with a free film 15, and in this state, the inner diameter of the cylindrical portion 20 is set. The weight 21 having a weight of 567 g that comes into contact with no gap is freely dropped from the upper end side. Then, the air compressed by the weight 21 is allowed to pass through the free film 15 in a circle having a diameter of 28.6 mm, and the time (sec) required for 100 mL of air to pass is measured.
And the time measured in this way is prescribed | regulated as permeation | transmission resistance (sec / 100mL).

Next, 2) a method for measuring the horizontal electronic resistance of the composite layer in the positive electrode will be described with reference to FIG.
In the measurement of the horizontal electronic resistance of the composite material layer in the positive electrode, after applying adhesive tape to the composite material layer 12 constituting the positive electrode material 10 to give cohesive force, the current collector foil 11 is removed with a width of 10 mm, First, a test sample 13 having an aspect as shown in FIG. 2 is prepared.

In such a test sample 13, the resistance value of the composite material layer 12 is measured by the tester 14 using the current collector foils 11 </ b> A and 11 </ b> B remaining on both sides of the part from which the current collector foil 11 is removed as a terminal.
The resistance value measured in this way is defined as the horizontal electronic resistance (Ω · cm).

The nonaqueous electrolyte secondary battery according to an embodiment of the present invention is managed so that the above-described transmission resistance and horizontal electronic resistance are each equal to or less than a predetermined threshold for the positive electrode constituting the nonaqueous electrolyte secondary battery. Thus, the capacity of the non-aqueous electrolyte secondary battery is increased.
Hereinafter, a specific method for managing the transmission resistance and the horizontal electronic resistance in the positive electrode will be described.

Next, a method for managing the positive electrode material 10 constituting the nonaqueous electrolyte secondary battery will be described with reference to FIG.
In the present embodiment, when a non-aqueous electrolyte secondary battery is manufactured using the positive electrode material 10 having the composite material layer 12 having a density of 2.8 g / cm ³ , the required amount of gas generated during overcharge is It is assumed that it is 55 mL / Ah or more.

Here, experimental results comparing the positive electrode materials 10, 10... Having a density of the composite layer 12 of 2.8 g / cm ³ manufactured by various manufacturing methods are shown.
More specifically, the permeation resistance is measured and compared for each of the free films 15, 15... Obtained from the respective positive electrode materials 10, 10.
In this experiment, a predetermined amount of overcharge additive capable of generating 55 mL / Ah or more of gas is added to the electrolytic solution for pulverizing the composite material layer 12 of the positive electrode material 10.
In the present embodiment, the non-aqueous electrolyte secondary battery according to the present invention is exemplified by a configuration in which an overcharge additive is added to the electrolytic solution, but the non-aqueous electrolyte secondary battery according to the present invention is For example, the structure by which the overcharge additive is added to the compound material layer (positive electrode material) may be sufficient.

And the measurement result in such an experiment is shown in FIG.
From FIG. 3, the free films 15, 15... Obtained from the respective positive electrode materials 10, 10... Manufactured by various manufacturing methods have a constant density (2.8 g / cm ³ ). However, it can be seen that the transmission resistance varies.
That is, it can be seen that the transmission resistance in the composite material layer 12 varies depending on the method of manufacturing the positive electrode material 10.

Further, it can be seen from FIG. 3 that there is a correlation between the permeation resistance and the amount of gas generated during overcharge.
That is, in each of the free films 15, 15... Having a constant density, it is recognized that the smaller the permeation resistance, the greater the amount of gas generated during overcharging. This is considered to be because, when the permeation resistance is different, the degree of penetration of the electrolyte solution into the composite material layer 12 changes, resulting in a difference in contact frequency between the composite material layer 12 (positive electrode) and the overcharge additive. .

Further, from FIG. 3, the composite material layer 12 having a horizontal electronic resistance of 8.5 Ω · cm or less has a larger amount of gas generation than the composite material layer 12 having a horizontal electronic resistance of more than 8.5 Ω · cm. It can be seen that, even in the free films 15 and 15 having substantially the same transmission resistance, if the horizontal electronic resistance is different, the amount of gas generation is different.
That is, in each of the free films 15, 15... Having a constant density, it is recognized that the smaller the horizontal electronic resistance, the greater the amount of gas generated during overcharge. This is because, as the horizontal electronic resistance is smaller, the structure distribution in the mixture layer 12 is more homogeneous (that is, the packing layer is not generated by the binder), and therefore the mixture layer 12 (positive electrode) and the overcharge additive This is probably because the contact frequency increases.

And from such a measurement result, when manufacturing a non-aqueous electrolyte secondary battery using the precondition (that is, the positive electrode material 10 having the composite material layer 12 having a density of 2.8 g / cm ³ ) In order to manage the positive electrode material 10 so as to satisfy the gas generation amount of 55 mL / Ah), only the transmission resistance of the free film 15 or only the horizontal electronic resistance of the composite layer 12 is used as an index. It can be seen that it is appropriate to manage in combination with the indicators of the transmission resistance and the horizontal electronic resistance.
This is considered to be because the composite material layer 12 having a lower permeation resistance and a lower horizontal electronic resistance has better electrolyte permeability and can efficiently generate gas with less overcharge additive. Because.

  That is, in the management of the positive electrode material 10, a threshold value for the transmission resistance with respect to the free film 15 and a threshold value for the horizontal electronic resistance are set according to the desired density of the composite material layer 12, and the transmission with respect to the free film 15 is performed. The positive electrode material 10 whose resistance measurement result is equal to or less than the threshold value and whose horizontal electronic resistance measurement result for the free film 15 is equal to or less than the threshold value is evaluated as a non-defective product.

Specifically, as shown in FIG. 3, the nonaqueous electrolyte secondary battery is based on the precondition that the density of the composite layer 12 is 2.8 g / cm ³ and a gas generation amount of 55 mL / Ah is secured. In the case of manufacturing, it is appropriate to manage the positive electrode material 10 by setting the threshold value of the transmission resistance to 250 sec / 100 mL or less and the threshold value of the horizontal electronic resistance to 8.5 Ω · cm or less.

In other words, according to FIG. 3, if it is desired to manufacture a nonaqueous electrolyte secondary battery in which the density of the composite layer 12 is 2.8 g / cm ³ and a gas generation amount of 55 mL / Ah is secured, It can be seen that the positive electrode material 10 having a resistivity of 250 sec / 100 mL or less and a horizontal electronic resistance of 8.5 Ω · cm or less may be used.

That is, the nonaqueous electrolyte secondary battery according to an embodiment of the present invention includes a pressure-type current interruption mechanism and an overcharge additive, and the density of the composite layer 12 in the positive electrode is 2.6 g / cm ³ or more. The air permeability resistance of the composite material layer 12 is 250 sec / 100 mL or less, and the horizontal electronic resistance of the composite material layer 12 is 8.5 Ω · cm or less.
With such a configuration, in a non-aqueous electrolyte secondary battery having a positive electrode with a high density (a density of 2.6 g / cm ³ or more), it is possible to secure the amount of gas generation necessary for operating the current interrupting mechanism. Moreover, the addition amount of an overcharge additive can be suppressed.
In addition, the density of the composite material layer 12 in the positive electrode can be increased, and as a result, the capacity of the nonaqueous electrolyte secondary battery can be increased.

Next, the nonaqueous electrolyte secondary in which the density of the composite material layer 12 is 2.6 g / cm ³ or more, the permeation resistance is 250 sec / 100 mL or less, and the horizontal electronic resistance is 8.5 Ω · cm or less. A method for producing the positive electrode material 10 for a battery (hereinafter referred to as a positive electrode material that satisfies the conditions) will be described with reference to FIG.

  As shown in FIG. 4, the positive electrode material 10 for constituting the nonaqueous electrolyte secondary battery includes a paste manufacturing step (hereinafter referred to as a paste manufacturing step (STEP-1)), and the manufactured paste is a current collector foil. Coating step (hereinafter referred to as coating step (STEP-2)), drying step of the coated paste (hereinafter referred to as drying step (STEP-3)), and composite material in which the paste has been dried It is manufactured through a step of pressing a member composed of a layer and a current collector foil (hereinafter referred to as a pressing step (STEP-4)).

  Of these steps (STEP-1) to (STEP-4), for example, in the pressing step (STEP-4), by adopting a predetermined pressing method, the positive electrode that reliably satisfies the above-mentioned preconditions. The material 10 can be manufactured.

Here, a pressing method for producing the positive electrode material 10 satisfying the above conditions will be described with reference to FIG.
In the method for manufacturing a non-aqueous electrolyte secondary battery according to an embodiment of the present invention, a predetermined pressing condition is selected in a pressing step in a manufacturing process of a positive electrode member for constituting the positive electrode of the non-aqueous electrolyte secondary battery. As a result, the capacity of the nonaqueous electrolyte secondary battery is increased.
Here, a case where the positive electrode material 10 in which the density of the composite layer 12 is 2.9 g / cm ³ is manufactured is illustrated.

FIG. 5 shows the measurement results of air permeability resistance, horizontal electronic resistance, and gas generation amount for the positive electrode material 10 manufactured under three types of pressing conditions.
As shown in FIG. 5, under the first pressing condition, the positive electrode material 10 was manufactured by setting the compression ratio of the composite material layer 12 to 50% and pressing the number of times once.
In this case, the positive electrode material 10 in which the air permeability resistance of the composite material layer 12 (free film 15) was 390 sec / 100 mL and the horizontal electronic resistance of the composite material layer 12 was 3.3 Ω · cm was generated.

Further, under the second pressing condition, the positive electrode material 10 was manufactured by setting the compression ratio of the composite material layer 12 to 47% and pressing the number of times 10 times.
In this case, the positive electrode material 10 in which the air permeability resistance of the composite material layer 12 (free film 15) was 292 sec / 100 mL and the horizontal electronic resistance of the composite material layer 12 was 3.9 Ω · cm was generated.

Furthermore, under the third condition, the positive electrode material 10 was manufactured by setting the compression rate of the composite material layer 12 to 37.5% and the number of presses to 20 times.
In this case, the positive electrode material 10 in which the air permeability resistance of the composite material layer 12 (free film 15) was 237 sec / 100 mL and the horizontal electronic resistance of the composite material layer 12 was 4.2 Ω · cm was generated.

According to the management standard obtained earlier, when the density of the composite layer 12 is 2.6 g / cm ³ or more and it is desired to produce the positive electrode material 10 that can secure the gas generation amount of 55 mL / Ah or more, It was found that the transmission resistance of the layer 12 (free film 15) should be 250 sec / 100 mL or less, and the horizontal electronic resistance of the composite material layer 12 should be 8.5 Ω · cm or less.

  When this management standard is applied to each of the positive electrode materials 10, 10, 10 manufactured based on the first to third press conditions, only the positive electrode material 10 manufactured under the third press conditions is managed. Each of the positive electrode materials 10 and 10 manufactured under the first and second press conditions does not comply with the management standard.

In addition, as a result of measuring the amount of gas generated during actual overcharge for each positive electrode material 10, 10, 10 manufactured based on the first to third press conditions, 38 mL was obtained under the first press condition. / Ah, the second press condition was 45 mL / Ah, and the third press condition was 57 mL / Ah.
That is, even in the measurement result of the actual gas generation amount, the gas generation amount of 55 mL / Ah or more can be secured only in the case of the third press condition. It was confirmed that the amount of gas generation could be secured.

Moreover, even if the manufacturing conditions from the paste manufacturing process (STEP-1) to the drying process (STEP-3) are the same, the amount of gas generated is different depending on the pressing conditions in the pressing process (STEP-4). It was confirmed that there was a difference in.
And the compressibility of the composite material layer 12 is set to 37.5% or less, and the air resistance of the composite material layer 12 can be reduced by performing the pressing a plurality of times, whereby the non-aqueous electrolyte secondary battery It was confirmed that the positive electrode material 10 satisfying the management standard for achieving a higher capacity can be manufactured.

That is, in the method for manufacturing a nonaqueous electrolyte secondary battery according to an embodiment of the present invention, the step of pressing the composite material layer 12 in the manufacturing process of the member constituting the positive electrode (that is, the positive electrode material 10) (that is, pressing) In the step (STEP-4)), the compression rate of the composite material layer 12 is set to 37.5% or less, and the composite material layer 12 is pressed a plurality of times (in this embodiment, 20 times), The density is 2.6 g / cm ³ or more.
With such a configuration, it is possible to reliably manufacture the positive electrode material 10 having a low air permeability resistance, and as a result, it is possible to increase the capacity of the nonaqueous electrolyte secondary battery.

  In addition, among the steps (STEP-1) to (STEP-4), for example, by setting a predetermined standard for the rheology of the paste in the paste manufacturing step (STEP-1), the above conditions can be reliably satisfied. It becomes possible to manufacture the positive electrode material 10 to be filled.

Here, the setting conditions of the paste for manufacturing the positive electrode material 10 satisfying the above conditions will be described with reference to FIGS. 6 and 7.
FIG. 6 shows the relationship between the transmission resistance and the migration index in the positive electrode material 10 in which the density of the composite layer 12 is 2.8 g / cm ³ .
The “migration index” referred to here is an index indicating the degree of uneven distribution of the binder in the paste, and the binder distribution is quantitatively read by EPMA (electron beam microanalyzer) analysis of the electrode cross section. This is a value obtained by dividing the upper half binder amount by the lower half binder amount of the composite material layer. The closer the migration index is to 1, the more uniformly the binder is distributed.
Further, the positive electrode material 10 used in the production of FIG. 6 is manufactured by a conventional method.

FIG. 6 shows that there is a correlation between the transmission resistance in the positive electrode material 10 and the migration index in the paste for producing the positive electrode material 10.
Further, FIG. 6 shows that the migration index of the paste for generating the composite material layer 12 should be 1.7 or less in order to make the air resistance less than 250 sec / 100 mL.

FIG. 7 shows the relationship between the viscosity of the paste and the migration index in the region where the shear rate is 0.2 sec ⁻¹ .
FIG. 7 shows that the migration index in the paste has a correlation with the viscosity of the paste.
FIG. 7 also shows that the viscosity of the paste in the region where the shear rate is 0.2 sec ⁻¹ should be 15000 mPa · sec or more in order to make the migration index of the paste 1.7 or less.

Then, in the paste manufacturing process (STEP-1), if the positive electrode material 10 is manufactured using a paste having a viscosity of 15000 mPa · sec or more in a region where the shear rate is 0.2 sec ⁻¹ , each subsequent process ( Even if STEP-2) to (STEP-4) are the same as before, the air permeation resistance can be reduced, whereby the management standard for achieving high capacity of the non-aqueous electrolyte secondary battery is established. It was confirmed that the positive electrode material 10 to be filled can be reliably manufactured.

  Moreover, from this result, even if the coating process (STEP-2) to the pressing process (STEP-4) are the same as the conventional manufacturing conditions, the rheology of the paste in the paste manufacturing process (STEP-1) is adjusted. It was found that there was a difference in the amount of gas generated.

That is, in the method for manufacturing a non-aqueous electrolyte secondary battery according to one embodiment of the present invention, the manufacture of a paste for generating the composite material layer 12 in the manufacturing process of the member constituting the positive electrode (that is, the positive electrode material 10). In the step (namely, paste manufacturing step (STEP-1)), the viscosity at the time of paste kneading is set to 15000 mPa · sec or more in a region where the shear rate is 0.2 sec ⁻¹ .
With such a configuration, it is possible to reliably manufacture the positive electrode material 10 having a low air permeability resistance, and as a result, it is possible to increase the capacity of the nonaqueous electrolyte secondary battery.

  In addition, in this embodiment, the rheology of the paste used as the raw material of the composite material layer 12 in a paste manufacturing process (STEP-1) is adjusted, or the device of the pressing method of the composite material layer 12 in a press process (STEP-4) is devised. The non-aqueous electrolyte secondary battery manufacturing method has been exemplified by improving the air resistance, but in addition, the drying time in the drying step (STEP-3) is increased, or coating is performed. It is considered that the air resistance can be improved by devising the coating method in the step (STEP-2).

10 Material for positive electrode 12 Compound material layer 15 Free film

Claims (3)

It has a pressure-type current interruption mechanism and an overcharge additive,
A non-aqueous electrolyte secondary battery in which the density of the composite layer in the positive electrode is 2.6 g / cm ³ or more,
The air resistance of the composite layer is 250 sec / 100 mL or less, and
The horizontal electronic resistance of the composite material layer is 8.5 Ω · cm or less.
A non-aqueous electrolyte secondary battery. It is a manufacturing method of the nonaqueous electrolyte secondary battery according to claim 1,
In the step of pressing the composite layer in the manufacturing process of the member constituting the positive electrode,
The compression ratio of the composite layer is 37.5% or less,
And pressing the composite layer multiple times,
The density of the composite material layer is 2.6 g / cm ³ or more.
A method for producing a non-aqueous electrolyte secondary battery. It is a manufacturing method of the nonaqueous electrolyte secondary battery according to claim 1,
In the manufacturing process of the paste for generating the composite material layer in the manufacturing process of the member constituting the positive electrode,
The viscosity at the time of kneading the paste,
In the region where the shear rate is 0.2 sec ⁻¹ , the pressure is 15000 mPa · sec or more.
A method for producing a non-aqueous electrolyte secondary battery.

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