JP2013054949A - Nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery inhibiting the growth of dendrites around the outer periphery of a negative electrode active material layer by relieving the current concentration around the outer periphery of the battery to effectively inhibit a short circuit in the battery associated with battery charging and discharging.SOLUTION: A nonaqueous electrolyte battery 100 comprises a positive electrode active material layer 12, a negative electrode active material layer 22, and a solid electrolyte layer (an SE layer 30) intervening between the active material layers 12 and 22. The nonaqueous electrolyte battery 100 further comprises an Si layer 40 between the SE layer 30 and the negative electrode active material layer 22. The Si layer 40 comprises an outer peripheral region 40h including the outer periphery, and a central region 40c located inside the outer peripheral region 40h, and the outer peripheral region 40h is thicker than the central region 40c.

Description

  The present invention relates to a non-aqueous electrolyte battery including a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer interposed between these active material layers. In particular, the present invention relates to a non-aqueous electrolyte battery that is unlikely to cause a short circuit even during repeated charge and discharge.

  A nonaqueous electrolyte battery including a positive electrode body, a negative electrode body, and an electrolyte layer disposed between these electrode bodies is used as a power source on the premise that charging and discharging are repeated. The electrode body included in the battery further includes a current collector having a current collecting function and an active material layer containing an active material. Among such non-aqueous electrolyte batteries, in particular, a non-aqueous electrolyte battery that charges and discharges by movement of Li ions between the positive and negative electrode bodies has a high discharge capacity while being small.

  In non-aqueous electrolyte batteries using Li ions, as the battery is charged and discharged, dendrites (needle-like Li crystals) are deposited on the surface of the negative electrode active material layer, and the dendrite grows to reach the positive electrode active material layer. Doing so may cause a short circuit. In order to solve this problem, it has been proposed to physically suppress dendrite growth by making the electrolyte layer a solid, as described in Patent Document 1, for example. Further, in Patent Document 1, an interface layer such as Si is formed between the negative electrode active material layer and the solid electrolyte layer, and Li transferred from the positive electrode active material layer through the solid electrolyte layer by the interface layer is used as the negative electrode active material. It has been proposed to diffuse into the layers. By doing so, the joining of a negative electrode active material layer and a solid electrolyte layer is maintained favorable, and the fall of the discharge capacity accompanying charging / discharging of a battery is suppressed.

JP 2009-277381 A

  However, even the nonaqueous electrolyte battery disclosed in Patent Document 1 may not be able to prevent a short circuit depending on how the battery is used.

  In a nonaqueous electrolyte battery having a solid electrolyte layer, current tends to concentrate on the outer peripheral edge side of the battery during charging and discharging, and this current concentration causes the amount of dendrite deposited on the outer peripheral edge side of the negative electrode active material layer. More than the central part. Therefore, if the dendrite deposited at the time of charging is recharged before it is sufficiently dissolved by discharging, the dendrite travels from the outer peripheral edge of the negative electrode active material layer to the side surface of the solid electrolyte layer, and the positive electrode active material layer May be short-circuited.

  The present invention has been made in view of the above circumstances, and one of its purposes is to suppress dendrite growth in the vicinity of the outer peripheral edge of the negative electrode active material layer by relaxing current concentration in the vicinity of the outer peripheral edge of the battery. Then, it is providing the nonaqueous electrolyte battery which can suppress effectively the short circuit of the battery accompanying charging / discharging of a battery.

(1) The nonaqueous electrolyte battery of the present invention includes a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer interposed between the two active material layers. This non-aqueous electrolyte battery of the present invention includes a Si layer between a solid electrolyte layer and a negative electrode active material layer, and the Si layer is located in an annular outer peripheral region including an outer peripheral edge portion thereof and in the outer peripheral region. And a central area. And the thickness of the said outer peripheral area | region is thick compared with a center area | region.

  The Si layer provided between the solid electrolyte layer and the negative electrode active material layer is divided into an outer peripheral region having a difference in thickness and a central region, and the outer peripheral region is made thicker than the central region, whereby the outer peripheral edge of the Si layer Li ion conductivity in the vicinity of the portion can be reduced, and current concentration in the vicinity of the outer peripheral edge of the nonaqueous electrolyte battery can be reduced. In particular, the current density in the battery surface can be made uniform by adjusting the thicknesses of the outer peripheral region and the central region. As a result, dendrite growth in the vicinity of the outer peripheral edge of the negative electrode active material layer can be suppressed, and a short circuit of the battery can be effectively prevented.

(2) As one form of the nonaqueous electrolyte battery of the present invention, it is preferable that the outer peripheral region has a substantially uniform thickness over the entire region, and the central region has a substantially uniform thickness over the entire region.

  Forming a region with a substantially uniform thickness is easier than forming a region with a gradual change in thickness. That is, it can be said that a non-aqueous electrolyte battery having an outer peripheral area and an inner peripheral area having a substantially uniform thickness is an easily manufactured battery.

(3) In the configuration in which the Si layer is divided into an outer peripheral region and a central region having a difference in thickness, the outer peripheral region is preferably 40 to 100 nm thicker than the central region.

  If the difference in thickness is 40 to 100 nm, the current density in the battery surface can be made uniform. As a result, a nonaqueous electrolyte battery in which delamination is less likely to occur, that is, a nonaqueous electrolyte battery excellent in cycle characteristics can be obtained.

(4) When the Si layer is divided into an outer peripheral region and a central region having a difference in thickness, the width of the outer peripheral region when the Si layer is viewed in plan is substantially equal over the entire circumference of the outer peripheral region. Is preferred.

  By forming a band-shaped outer peripheral region in which the width from the outer peripheral edge of the Si layer is substantially equal over the entire periphery, current concentration in the vicinity of the outer peripheral edge of the negative electrode active material layer can be effectively reduced.

(5) As one form of this invention nonaqueous electrolyte battery, it is preferable that the area ratio of the said outer periphery area | region when planarly viewing the said Si layer is 50% or less.

  By setting the area ratio of the outer peripheral region in the Si layer to 50% or less, it is possible to effectively suppress dendrite growth at the outer peripheral edge of the negative electrode active material layer without reducing the discharge capacity of the nonaqueous electrolyte battery.

  According to the configuration of the non-aqueous electrolyte battery of the present invention, it is possible to obtain a battery in which short-circuiting of the battery hardly occurs even when charging and discharging are repeated.

(A) is a schematic sectional drawing of the nonaqueous electrolyte battery of this invention which concerns on embodiment, (B) is the schematic sectional drawing which deformed and showed the formation state of Si layer and solid electrolyte layer with which a nonaqueous electrolyte battery is equipped. It is explanatory drawing which shows the state before joining of each electrode body in this invention nonaqueous electrolyte battery which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Overall configuration of nonaqueous electrolyte battery>
A nonaqueous electrolyte battery 100 shown in FIG. 1A includes a positive electrode current collector 11, a positive electrode active material layer 12, a solid electrolyte layer (SE layer) 30, a Si layer 40, a negative electrode active material layer 22, and a negative electrode current collector. 21. The most characteristic feature of this nonaqueous electrolyte battery 100 is that the thickness of the Si layer 40 provided in the battery 100 is the largest at the outer peripheral edge (see FIG. 1B). Hereinafter, the details of each part will be sequentially described, and an example of the manufacturing method will also be shown.

≪Positive electrode current collector≫
The positive electrode current collector 11 may be composed of only a conductive material, or may be composed of a conductive material film formed on an insulating substrate. In the latter case, the conductive material film functions as a current collector. As the conductive material, one selected from Al, Ni, alloys thereof, and stainless steel can be suitably used.

≪Positive electrode active material layer≫
The positive electrode active material layer 12 is a layer containing positive electrode active material particles that are the main component of the battery reaction. As the positive electrode active material, a material having a layered rock salt type crystal structure, for example, Liα _X β _(1-X) O ₂ (α is one selected from Co, Ni, Mn, β is Fe, Al, Ti , Cr, Zn, Mo, Bi, Co, Ni, and Mn, α ≠ β, and X is 0.5 or more). Specific examples thereof include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiNi _0.5 Mn _0.5 O ₂ , LiCo _0.5 Fe _0.5 O ₂ , LiCo _0.5 Al _0.5 O ₂ , LiNi _{1. / 3} Mn _1/3 Co _1/3 O ₂ , LiNi _0.8 Co _0.15 Al _0.05 O _{2 and the} like. In addition, as a positive electrode active material, a substance having a spinel crystal structure (for example, LiMn ₂ O ₄ or the like) or a substance having an olivine crystal structure (for example, Li _X FePO ₄ (0 <X <1)) is used. It can also be used.

The positive electrode active material layer 12 may contain electrolyte particles that improve the Li ion conductivity of the layer 12. As the electrolyte particles, for _example, it can be suitably used sulfides such as _{Li 2 S-P 2 S 5} . The sulfide may further contain an oxide such as P ₂ O ₅ . In addition, the positive electrode active material layer 12 may contain a conductive additive or a binder.

≪SE layer≫
The SE layer 30 is a layer containing a solid electrolyte having high Li ion conductivity and low electron conductivity. Examples of the solid electrolyte include oxides such as LiPON and Li ₂ S—P ₂ S ₅ (which may contain an oxide such as P ₂ O ₅ as necessary). In particular, it is preferable to use a solid electrolyte made of sulfide having high Li ion conductivity and low electron conductivity. The solid electrolyte constituting the SE layer 30 may be amorphous or crystalline. However, in order to satisfy the requirements for high Li ion conductivity and low electron conductivity required for the SE layer 30, a crystal may be used. A solid electrolyte is preferable.

  The thickness of the SE layer 30 is preferably 5 to 10 μm. With the SE layer 30 having this thickness, the positive electrode active material layer 12 and the negative electrode active material layer 22 can be reliably insulated while avoiding an increase in the thickness of the nonaqueous electrolyte battery 100.

≪Si layer≫
The Si layer 40 is for diffusing Li, which has moved from the positive electrode active material layer 12 through the SE layer 30 during battery charging, to the negative electrode active material layer 22. This Si layer 40 makes it difficult for the dendrite to precipitate on the negative electrode active material layer 22.

  The thickness of the outer peripheral edge portion of the Si layer 40 is set to be the thickest as compared with other portions. When the Si layer 40 is thickened, the Li ion conductivity decreases in the thickness direction of the battery 100 by that amount. As a result, current concentration in the vicinity of the outer peripheral edge of the battery 100 can be reduced, and dendrite growth in the vicinity of the outer peripheral edge of the negative electrode active material layer 22 can be suppressed.

  The Si layer 40 only needs to have the maximum thickness at the outer peripheral edge thereof, and can be formed into a mortar shape in which the thickness gradually decreases toward the central portion of the Si layer 40, for example. In addition, as shown in FIG. 1B, the Si layer 40 may be divided into an outer peripheral region 40h and a central region 40c having different thicknesses. Hereinafter, the configuration divided into the outer peripheral region 40h and the central region 40c will be mainly described. FIG. 1B shows a deformed state of the Si layer 40 and the SE layer 30, and the SE layer 30 is actually about 1000 times thicker than the Si layer 40.

[Outer peripheral area and central area]
In the Si layer 40 of FIG. 1B, the negative electrode active material layer 22 side (upper side of the drawing, see FIG. 1A) is a flat surface, and a step is formed on the SE layer 30 side. This is because the Si layer 40 is laminated on the negative electrode active material layer 22 in the method for manufacturing a nonaqueous electrolyte battery described later. Therefore, when the Si layer 40 is stacked on the SE layer 30 side, the surface facing the SE layer 30 of the Si layer 40 is flat, and a step is formed on the surface facing the negative electrode active material layer 22. Anyway.

  The outer peripheral region 40 h of the Si layer 40 is an annular region including the outer peripheral edge portion of the Si layer 40. The thickness is preferably in the range of 90 to 200 nm. By setting the outer peripheral region 40 h to 90 nm or more, Li that has moved from the positive electrode active material layer 12 when the battery 100 is charged can be effectively dispersed in the negative electrode active material layer 22. Moreover, it can avoid that Li ion conductivity in the outer periphery area | region 40h falls too much by making the thickness of the outer periphery area | region 40h 200 nm or less.

  The central region 40c is a region located inward of the outer peripheral region 40h, and a step is formed at a boundary portion between the outer peripheral region 40h and the central region 40c. The thickness of the central region 40c is preferably in the range of 50 to 100 nm. By setting the thickness of the central region 40c within the above range, Li that has moved from the positive electrode active material layer 12 when the battery 100 is charged can be effectively dispersed in the negative electrode active material layer 22, and Li ion conduction in the central region 40c. It can also be avoided that the performance is too low.

  The difference between the thickness of the outer peripheral region 40h and the thickness of the central region 40c (step between the regions 40h and 40c) is preferably in the range of 40 to 100 nm. If the level difference is too large, the amount of dendrite deposited in the portion corresponding to the central region 40c will be larger than the amount of dendrite deposited in the portion corresponding to the outer peripheral region 40h, and delamination may occur in the former portion. is there.

  By dividing into the outer peripheral region 40h and the central region 40c having different thicknesses, the current density in the surface of the battery 100 can be averaged, and the amount of dendrite deposited in the surface of the negative electrode active material layer 22 is also made uniform. be able to. As a result, it is possible to avoid locally increasing the amount of dendrite, and delamination hardly occurs.

  The width of the outer peripheral area 40h, that is, the length from the outer peripheral edge of the Si layer 40 to the boundary with the central area 40c is preferably substantially uniform over the entire circumference of the outer peripheral area 40h. This is because if there is a portion where the width is locally narrow, the current may concentrate on that portion.

  The area ratio of the outer peripheral region 40h when the Si layer 40 is viewed in plan is preferably 50% or less. By setting the area ratio of the outer peripheral region 40h to 50% or less, the Li ion conductivity of the entire battery 100 can be ensured. Here, since the Li ion conductivity of the battery 100 as a whole improves as the area ratio of the outer peripheral region 40h decreases, the discharge capacity of the battery 100 also improves. However, from the viewpoint of effectively reducing current concentration and improving the cycle characteristics of the battery 100, the area ratio of the outer peripheral region 40h is preferably 20% or more.

≪Negative electrode active material layer≫
The negative electrode active material layer 22 is a layer containing negative electrode active material particles that are the main component of the battery reaction. As the negative electrode active material, C, Si, Ge, Sn, Al, a Li alloy, or an oxide containing Li such as Li ₄ Ti ₅ O ₁₂ can be used.

The negative electrode active material layer 22 may contain electrolyte particles that improve the Li ion conductivity of the layer 22. As the electrolyte particles, for example, sulfides such as Li ₂ S—P ₂ S ₅ (which may contain an oxide as necessary) can be suitably used. In addition, the negative electrode active material layer 22 may contain a conductive additive or a binder.

≪Negative electrode current collector≫
The negative electrode current collector 21 may be composed of only a conductive material, or may be composed of a conductive material film formed on an insulating substrate. In the latter case, the conductive material film functions as a current collector. As the conductive material, for example, one selected from Cu, Ni, Fe, Cr, and alloys thereof (for example, stainless steel) can be suitably used.

≪Other composition≫
When the SE layer 30 includes a sulfide solid electrolyte, the sulfide solid electrolyte reacts with the positive electrode active material of the oxide included in the positive electrode active material layer 12 adjacent to the SE layer 30 to form the positive electrode active material layer 12 and the SE. There is a possibility that the vicinity of the interface with the layer 30 is increased in resistance, and the discharge capacity of the nonaqueous electrolyte battery 100 is reduced. Therefore, an intermediate layer (not shown) may be provided between the positive electrode active material layer 12 and the SE layer 30 in order to suppress the increase in resistance near the interface. As a material used for the intermediate layer, an amorphous Li ion conductive oxide such as LiNbO ₃ or LiTaO ₃ can be used. In particular, LiNbO ₃ can effectively suppress an increase in resistance near the interface between the positive electrode active material layer 12 and the SE layer 30.

<Effect of non-aqueous electrolyte battery>
The nonaqueous electrolyte battery 100 described above is not easily short-circuited even if charging and discharging are repeated. This is because by providing the outer peripheral region 40 h including the outer peripheral edge in the Si layer 40, current concentration in the vicinity of the outer peripheral edge of the battery 100 can be alleviated, and thus dendrite growth in the vicinity of the outer peripheral edge can be suppressed. Further, by relaxing current concentration in the vicinity of the outer peripheral edge of the battery 100, it is possible to suppress the occurrence of in-plane distribution in the generation of dendrites associated with charging / discharging of the battery 100. The bonding state between 22 and the SE layer 30 can be kept good. As a result, the nonaqueous electrolyte battery 100 of the present invention becomes a battery 100 having excellent cycle characteristics.

<Method for producing non-aqueous electrolyte battery>
The non-aqueous electrolyte battery 100 may be manufactured by sequentially stacking each layer from the positive electrode current collector 11 side, or may be manufactured by sequentially stacking each layer from the negative electrode current collector 21 side. The positive electrode body 1 including the positive electrode active material layer 12 and the negative electrode body 2 including the negative electrode active material layer 22 may be separately manufactured, and the electrode bodies 1 and 2 may be bonded together. Hereinafter, the case where the electrode bodies 1 and 2 are produced separately will be described with reference to the explanatory view of FIG.

When the non-aqueous electrolyte battery 100 is manufactured by laminating the separately manufactured electrode bodies 1 and 2, for example, a manufacturing method including the following steps (A) to (C) can be used.
(A) The positive electrode body 1 is produced.
(B) The negative electrode body 2 is produced.
(C) The positive electrode body 1 and the negative electrode body 2 are superposed and subjected to heat treatment while being pressurized, so that the positive electrode body 1 and the negative electrode body 2 are joined.
* The order of the steps (A) and (B) can be changed.

<< Step A: Production of positive electrode body >>
The illustrated positive electrode body 1 has a configuration in which a positive electrode active material layer 12 and a positive electrode side solid electrolyte layer (PSE layer) 13 are laminated on a positive electrode current collector 11. In order to produce the positive electrode body 1, a substrate to be the positive electrode current collector 11 is prepared, and the remaining layers 12 and 13 may be sequentially formed on the substrate. The positive electrode current collector 11 may be formed on the surface of the positive electrode active material layer 12 opposite to the PSE layer 13 after the step C of bonding the positive electrode body 1 and the negative electrode body 2.

  The positive electrode active material layer 12 can be formed by, for example, a pressure molding method. In that case, a mixed powder including an active material powder made of positive electrode active material particles and an electrolyte powder made of electrolyte particles is prepared. And mixed powder is arrange | positioned on the positive electrode collector 11 arrange | positioned in a metal mold | die, and it pressure-molds. The conditions for this pressure molding can be selected as appropriate. For example, it is good to press-mold by the surface pressure of 100-400 MPa in the atmosphere of room temperature-300 degreeC. Moreover, the average particle diameter of the positive electrode active material particles to be pressure-molded is preferably 1 to 20 μm. Furthermore, if electrolyte particles are used, the average particle size of the electrolyte particles is preferably 0.5 to 2 μm.

  The positive electrode side solid electrolyte layer (PSE layer) 13 is integrated with a later-described negative electrode side solid electrolyte layer 23 through a later step C, and becomes a part of the SE layer 30 of the completed battery 100 shown in FIG. . A gas phase method can be used to form the PSE layer 13. As the vapor phase method, for example, a vacuum deposition method, a sputtering method, an ion plating method, a laser ablation method, or the like can be used.

<< Step B: Production of negative electrode body >>
The negative electrode body 2 has a configuration in which a negative electrode active material layer 22, a Si layer 40, and a negative electrode side solid electrolyte layer (NSE layer) 23 are laminated on a negative electrode current collector 21. In order to produce the negative electrode body 2, a substrate to be the negative electrode current collector 21 is prepared, and the remaining layers 22, 40, and 23 are sequentially formed on the substrate. The negative electrode current collector 21 may be formed on the surface of the negative electrode active material layer 22 opposite to the NSE layer 23 after Step C.

  The negative electrode active material layer 22 can be produced by a pressure molding method, similarly to the positive electrode active material layer 12. For example, the negative electrode active material powder composed of the negative electrode active material particles and the solid electrolyte powder are mixed, and the mixed powder is pressure-molded on the negative electrode current collector 21 arranged in a mold. The conditions for this pressure molding can be selected as appropriate. For example, it is good to press-mold by the surface pressure of 100-400 MPa in the atmosphere of room temperature-300 degreeC. Moreover, the average particle diameter of the negative electrode active material particles to be pressure-molded is preferably 1 to 20 μm. Furthermore, if electrolyte particles are used, the average particle size of the electrolyte particles is preferably 0.5 to 2 μm.

  The Si layer 40 formed on the negative electrode active material layer 22 is divided into an outer peripheral region 40h and a central region 40c having different thicknesses. In order to form a difference in thickness between the two regions 40h and 40c, for example, Si having a substantially uniform thickness is formed on the negative electrode active material layer 22 by a vapor phase method, and then a mask is formed in a portion that becomes the central region 40c. Further, it is preferable to form a Si film by a vapor phase method. Since the Si layer 40 has a nano-order thickness, it is difficult to form the Si layer 40 by a method other than the vapor phase method.

  The negative electrode side solid electrolyte layer (NSE layer) 23 becomes a part of the SE layer 30 through the following step C, similarly to the PSE layer 13 described above. The NSE layer 23 and the PSE layer 13 described above preferably have the same composition and manufacturing method. By doing so, when the NSE layer 23 and the PSE layer 13 become one SE layer 30 through the next step C, variations in Li ion conductivity hardly occur in the thickness direction of the SE layer 30.

<< Step C: Joining of Positive Electrode and Negative Electrode >>
Next, the positive electrode body 1 and the negative electrode body 2 are laminated so that the PSE layer 13 and the NSE layer 23 face each other to produce a laminated body. At that time, heat treatment is performed while the PSE layer 13 and the NSE layer 23 are in pressure contact with each other, so that the PSE layer 13 and the NSE layer 23 are integrated.

  The heat treatment conditions in Step C vary depending on the effects of the composition of the PSE layer 13 and the NSE layer 23, but are preferably about 150 to 300 ° C. for 1 to 60 minutes. More preferable heat treatment conditions are 180 to 250 ° C. × 30 to 60 minutes.

  In step C, the PSE layer 13 and the NSE layer 23 are pressurized in the direction of approaching during the heat treatment. Although the pressure of the pressurization is very small, there is an effect of promoting the integration of the PSE layer 13 and the NSE layer 23. However, the higher the pressure, the easier the integration. However, when the pressure of the pressurization is increased, there is a risk that defects such as cracking may occur in each layer provided in the positive electrode body 1 and the negative electrode body 2. In particular, the positive electrode active material layer 12 and the negative electrode active material layer 22 that are powder compacts are easily cracked. Since the integration of the PSE layer 13 and the NSE layer 23 is only caused by heat treatment, a pressure of 10 to 20 MPa is sufficient.

  By performing step C, as shown in FIG. 1A, a nonaqueous electrolyte battery 100 including one SE layer 30 is formed. Although this one-layer SE layer 30 is formed by integrating the PSE layer 13 and the NSE layer 23 as described above, the interface between the PSE layer 13 and the NSE layer 23 hardly remains. Therefore, the SE layer 30 does not have a decrease in Li ion conductivity due to the interface, and becomes an SE layer 30 having high Li ion conductivity and low electron conductivity.

  As mentioned above, according to the manufacturing method of a nonaqueous electrolyte battery provided with the illustrated steps A to C, the nonaqueous electrolyte battery 100 of the present invention described with reference to FIG. 1 can be manufactured.

<Test example>
A nonaqueous electrolyte battery 100 was fabricated using a positive electrode body 1 and a negative electrode body 2 having the following configuration. And the charging / discharging cycle test was done with respect to the obtained battery on the conditions mentioned later.

As the positive electrode body 1, the following one type was produced.
≪Positive electrode body A≫
Positive electrode current collector 11: diameter 15 mm, thickness 500 μm Al foil Positive electrode active material layer 12: pressure formed body of LiCoO ₂ powder and Li ₂ S—P ₂ S ₅ powder 15 mm in diameter and thickness 100 μm (LiCoO ₂ : Li ₂ S—P ₂ S ₅ = 70% by mass: 30% by mass)
PSE layer 13: Amorphous Li ₂ S—P ₂ S ₅ film having a diameter of 10 mm and a thickness of 10 μm (vacuum deposition method)

On the other hand, four types of negative electrode bodies 2 with different configurations of the Si layer 40 were produced as the negative electrode body 2. The difference between each negative electrode body 2 is that the thickness of the central region 40c and the outer peripheral region 40h constituting the Si layer 40 is different.
≪Negative electrode body 2≫
・ Negative electrode current collector 21... Stainless steel foil having a diameter of 16 mm and a thickness of 100 .mu.m. Negative electrode active material layer 22... Li film having a diameter of 10 mm and a thickness of 200 .mu.m
Si layer 40: a central region 40c having a diameter of 8 mm, an annular outer peripheral region having an inner diameter of 8 mm and an outer diameter of 10 mm (sputtering method);
NSE layer 23: amorphous Li ₂ S—P ₂ S ₅ film (vacuum deposition method) having a diameter of 10 mm and a thickness of 10 μm

  Next, in the atmosphere having a dew point temperature of −50 ° C., the prepared positive electrode body 1 and negative electrode body 2 are overlapped so that the PSE layer 13 and the NSE layer 23 are in contact with each other, and subjected to pressure heat treatment. A nonaqueous electrolyte battery (samples α to δ) was produced.

Next, 10 cycles of charge / discharge cycle tests were performed on the fabricated batteries of samples α to δ. The test conditions were a current density of 0.05 mA / cm ² and a cut-off voltage of 3.0 V to 4.1 V. Table 1 shows the configuration of the Si layer 40 of the samples α to δ, and the capacity retention rate after 10 cycles of charge / discharge (discharge capacity at 10 cycles / maximum discharge capacity) / discharge capacity (mAh / cm ² ).

  As shown in Table 1, the capacity retention rate (58 to 86%) of the samples β to δ in which the Si layer 40 is composed of the central region 40c and the outer peripheral region 40h having different thicknesses is a sample in which the thickness of the Si layer 40 is uniform. It was larger than the capacity retention rate of α (55%). In the samples β to δ in which the Si layer is divided into the outer peripheral region 40h and the central region 40c having different thicknesses, the current density in the battery surface can be made uniform, and the dendrite in the surface of the negative electrode active material layer 22 can be obtained. This is probably because the difference in the amount of precipitation was also reduced. When there is an in-plane distribution of the amount of dendrites deposited, delamination is likely to occur at locations where the amount of dendrites deposited is large.

  Further, when comparing the samples β to δ, the capacity retention rate (86%) of the sample γ in which the thickness of the outer peripheral region 40h is made larger in the range of 40 to 100 nm than the thickness of the central region 40c is that of the other samples β and δ. It was higher than the capacity maintenance rate. That is, it was found that the capacity retention rate of the nonaqueous electrolyte battery 100 can be significantly improved by making the thickness of the outer peripheral region 40h not only thicker than the thickness of the central region 40c but also within a predetermined range. This is presumably because the current density in the battery surface was made more uniform by adjusting the relative thicknesses of the outer peripheral region 40h and the central region 40c.

  In addition, this invention is not necessarily limited to the above-mentioned embodiment, In the range which does not deviate from the summary of this invention, it can change suitably and can implement.

  The non-aqueous electrolyte battery of the present invention can be suitably used as a power source for electric devices based on repeated charge and discharge, for example, a power source for various electronic devices, and can also be expected to be used as a power source for hybrid vehicles and electric vehicles.

DESCRIPTION OF SYMBOLS 100 Nonaqueous electrolyte battery 1 Positive electrode body 11 Positive electrode collector 12 Positive electrode active material layer 13 Positive electrode side solid electrolyte layer (PSE layer)
2 negative electrode body 21 negative electrode current collector 22 negative electrode active material layer 23 negative electrode side solid electrolyte layer (NSE layer)
30 Solid electrolyte layer (SE layer)
40 Si layer 40h Outer peripheral region 40c Central region

Claims (5)

A non-aqueous electrolyte battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer interposed between both active material layers,
A Si layer is provided between the solid electrolyte layer and the negative electrode active material layer,
The Si layer is composed of an annular outer peripheral region including an outer peripheral edge portion thereof, and a central region located inside the outer peripheral region,
The non-aqueous electrolyte battery characterized in that the outer peripheral region is thicker than the central region. The outer peripheral area has a substantially uniform thickness over the entire area,
The non-aqueous electrolyte battery according to claim 1, wherein the central region has a substantially uniform thickness over the entire region.   The non-aqueous electrolyte battery according to claim 2, wherein the outer peripheral region is 40 to 100 nm thicker than the central region.   4. The nonaqueous electrolyte battery according to claim 2, wherein the width of the outer peripheral region when the Si layer is viewed in plan is substantially equal over the entire periphery of the outer peripheral region. 5.   The nonaqueous electrolyte battery according to claim 2, wherein an area ratio of the outer peripheral region when the Si layer is viewed in plan is 50% or less.

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