Stacked battery

Abstract

To suppress a dimension of a lamination direction of a laminated battery.SOLUTION: In a laminated battery 100, an electrode body 10 in which a positive electrode collector 1, a positive electrode 2, an electrolyte, a negative electrode 4, and a negative electrode collector 5 are laminated in this order, and a single battery 100-1 having an insulation material 20 and an insulation material 30 are laminated. The positive electrode collector 1 includes: a first part 11; a second part 12; and a third part 13 that is extended to a lamination direction, and connects the first part 11 and the second part 12. The second part 12 is arranged to a side opposite to the first part 51 with the separation of the insulation material 30. The negative electrode collector 5 includes: the first part 51; a second part 52; and a third part 53 that is extended to the lamination direction, and connects the first part 51 and the second part 52. The second part 52 is arranged to a side opposite to the first part 11 with the separation of the insulation material 20. The insulation material 20 is arranged so that the same is overlapped neither the insulation material 30 nor the second part 12 in the lamination direction. The second part 52 is arranged so that the same is overlapped neither the insulation material 30 nor the second part 12 in the lamination direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a stacked battery. [Background technology]

[0002] Patent Document 1 describes a technology for realizing parallel or series connection of multiple cells by stacking unit cells of an all-solid-state battery. In the technology described in Patent Document 1, insulating substrates are disposed on the upper and lower sides of a power generating element in which a positive electrode current collector, a positive electrode, a solid electrolyte, a negative electrode, and a negative electrode current collector are stacked, and a metal pattern (extraction electrode) is provided on the upper surface of the upper insulating substrate, and a metal pattern (extraction electrode) is provided on the lower surface of the lower insulating substrate, thereby forming a unit cell of an all-solid-state battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-168416 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, for example, when two unit cells are stacked, a metal pattern provided on the lower surface of the lower insulating substrate of the upper unit cell is brought into contact with a metal pattern provided on the upper surface of the upper insulating substrate of the lower unit cell. In other words, in the technology described in Patent Document 1, for example, when two unit cells are stacked, the lower insulating substrate of the upper unit cell, the metal pattern provided on the lower surface of the lower insulating substrate of the upper unit cell, the upper insulating substrate of the lower unit cell, and the metal pattern provided on the upper surface of the upper insulating substrate of the lower unit cell are present between the power generating element of the upper unit cell and the power generating element of the lower unit cell. Therefore, the technology described in Patent Document 1 cannot sufficiently reduce the dimension in the stacking direction of a stacked battery formed by stacking a plurality of unit cells.

[0005] In view of the above, an object of the present disclosure is to provide a stacked battery capable of suppressing the dimension in the stacking direction. [Means for solving the problem]

[0006] (1) One aspect of the present disclosure is a stacked battery in which unit cells are stacked, each unit cell having an electrode assembly in which a positive electrode collector, a positive electrode, an electrolyte, a negative electrode, and a negative electrode collector are stacked in this order, a first insulating material arranged on the opposite side of the positive electrode across a first portion of the positive electrode collector, and a second insulating material arranged on the opposite side of the negative electrode across the first portion of the negative electrode collector, wherein the positive electrode collector has the first portion of the positive electrode collector, the second portion of the positive electrode collector, and a third portion of the positive electrode collector that extends in a stacking direction of the unit cells and connects the first portion of the positive electrode collector and the second portion of the positive electrode collector, and the second portion of the positive electrode collector is in contact with the first portion of the negative electrode collector across the second insulating material. the negative electrode current collector has a first portion of the negative electrode current collector, a second portion of the negative electrode current collector, and a third portion of the negative electrode current collector extending in the stacking direction to connect the first portion of the negative electrode current collector and the second portion of the negative electrode current collector, the second portion of the negative electrode current collector is disposed on the opposite side to the first portion of the positive electrode current collector across the first insulating material, the first insulating material is disposed so as not to overlap with either the second insulating material or the second portion of the positive electrode current collector in the stacking direction, and the second portion of the negative electrode current collector is disposed so as not to overlap with either the second insulating material or the second portion of the positive electrode current collector in the stacking direction.

[0007] (2) In the stacked battery of (1), the electrolyte may be a solid electrolyte.

[0008] (3) In the stacked battery of (1), the thickness of the unit cell may be 0.1 to 2 mm.

[0009] (4) In the stacked battery of (1), the third portion of the positive electrode current collector may be disposed on an opposite side to the third portion of the negative electrode current collector, across the positive electrode, the electrolyte, and the negative electrode. Effect of the Invention

[0010] According to the present disclosure, the dimension of the stacked battery in the stacking direction can be reduced. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of a stacked battery 100 according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of single cells 100-1, 100-2 included in a stacked battery 100 according to the first embodiment. [Diagram 3] 3 is a photograph of a prototype of the unit cell 100-1 shown in FIG. 2(A). [Figure 4] FIG. 10 is a diagram illustrating an example of cells 100-1, 100-2 included in a stacked battery 100 according to a second embodiment. [Diagram 5] 2A to 2C are diagrams illustrating a manufacturing process for the laminated battery 100 of the embodiment. [Figure 6] 2A to 2C are diagrams illustrating a manufacturing process for the laminated battery 100 of the embodiment. [Figure 7] 2A to 2C are diagrams illustrating a manufacturing process for the laminated battery 100 of the embodiment. [Figure 8] 7(A) and a cell 100-2 having the same structure as the cell 100-1. FIG. [Figure 9] 1 is a diagram showing a comparison between the cell capacity of a cell 100-1, a cell capacity of a cell 100-2, and a cell capacity of a stacked battery 100. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a stacked battery according to the present disclosure will be described with reference to the drawings.

[0013] First Embodiment FIG. 1 is a diagram that shows an example of a stacked battery 100 of the first embodiment. In detail, FIG. 1(A) shows an example of a cross section of the stacked battery 100 of the first embodiment, FIG. 1(B) shows an extracted positive electrode current collector 1 of the unit cell 100-1 included in the stacked battery 100 of the first embodiment shown in FIG. 1(A), and FIG. 1(C) shows an extracted negative electrode current collector 5 of the unit cell 100-1 included in the stacked battery 100 of the first embodiment shown in FIG. 1(A). FIG. 2 is a diagram that shows an example of the unit cells 100-1 and 100-2 included in the stacked battery 100 of the first embodiment. In detail, FIG. 2(A) shows the unit cell 100-1 from the lower side of FIG. 1(A), and FIG. 2(B) shows the unit cell 100-2 from the upper side of FIG. 1(A). FIG. 3 is a photograph of a prototype of the unit cell 100-1 shown in FIG. 2(A).

[0014] In the example shown in FIGS. 1 to 3, the stacked battery 100 includes a cell 100-1 and a cell 100-2, and is configured by stacking the cell 100-1 and the cell 100-2. In another example, the stacked battery 100 may include any number of unit cells other than two (but more than one), and may be constructed by stacking the unit cells.

[0015] In the example shown in FIGS. 1 to 3, the unit cell 100-1 and the unit cell 100-2 have the same configuration. In another example, the configurations of the multiple cells included in the stacked battery 100 do not have to be completely identical to each other.

[0016] In the example shown in FIGS. 1 to 3, a cell 100-1 has an electrode assembly 10, a first insulating material 20, and a second insulating material 30. In the example shown in FIGS. The first insulating material 20 and the second insulating material 30 are made of, for example, a resin material having an electrical insulating function and a sealing function (sealing function). Specifically, in the example shown in FIG. 3, the first insulating material 20 and the second insulating material 30 are made of a PP (polypropylene) film. In another example, the first insulating material 20 and the second insulating material 30 may be made of a resin material other than a PP film (provided that the resin material has an electrical insulating function and a sealing function).

[0017] In the example shown in FIGS. 1 to 3, the electrode body 10 is formed by laminating a positive electrode current collector 1, a positive electrode 2, a separator 3 containing an electrolyte (e.g., a separator 3 impregnated with an electrolyte), a negative electrode 4, and a negative electrode current collector 5 in this order. Any material that can be used as a positive electrode current collector for this type of battery can be used without any particular limitation as the positive electrode current collector 1. Typically, the positive electrode current collector 1 is made of a metal material having good electrical conductivity, such as aluminum, nickel, titanium, stainless steel, etc. The positive electrode current collector 1 is preferably an oxidation-resistant current collector. In the example shown in Fig. 3, an aluminum foil is used as the positive electrode current collector 1.

[0018] The positive electrode material constituting the positive electrode 2 may be, for example, a mixture of LiNiCoMn, SE (Solid Electrolyte) (LiI-LiBr-Li2S-P2S5), VGCF (Vapor-grown Carbon Fiber), and SBR (Styrene-Butadiene Rubber). There is no specification for the positive electrode active material, conductive additive, and binder contained in the positive electrode 2. That is, the positive electrode 2 may contain an electrolyte. When the positive electrode 2 contains an electrolyte, the electrolyte is preferably a solid electrolyte (sulfide, oxide) having high heat resistance. This is because a solid electrolyte that is resistant to heat is required for heat welding the first insulating material 20 and the second insulating material 30 as sealing materials. For example, a positive electrode active material, a conductive additive, a binder (binder), and an organic solvent (e.g., N-methyl-2-pyrrolidone (NMP)) are kneaded to obtain a positive electrode composite paste, which is then coated on a positive electrode current collector 1 and dried to form a positive electrode composite layer on the positive electrode current collector 1. The positive electrode composite layer is then rolled to a predetermined thickness to produce a positive electrode 2. Examples of the positive electrode active material include LiCoO2, LiNiO2, LiNi a Co bO2 (a + b = 1, 0 < a < 1, 0 < b < 1), LiMnO2, LiMn2O4, LiNi a Co b Mn c O2 (a + b + c = 1, 0 < a < 1, 0 < b < 1, 0 < c < 1), LiFePO4, etc. can be used. As the conductive auxiliary material, for example, acetylene black (AB) etc. can be used, and as the binder, for example, polyvinylidene fluoride (PVdF) etc. can be used.

[0019] Due to the reasons described above, the electrolyte contained in the separator 3 is preferably a solid electrolyte with high heat resistance. In the example shown in Figure 3, as the material constituting the separator 3, a mixture of SE and SBR is used. The separator 3 may substantially consist of a solid electrolyte material. The separator 3 may further contain, for example, a binder etc. The separator 3 may contain any solid electrolyte material. The separator 3 may contain, for example, a Li2S - P2S5 - based solid electrolyte etc.

[0020] As the negative electrode material constituting the negative electrode 4, for example, a mixture of graphite, SE (LiI - LiBr - Li2S - P2S5), VGCF, and SBR can be used. There is no specification for the negative electrode active material, conductive auxiliary agent, and binder contained in the negative electrode 4. That is, the negative electrode 4 may contain an electrolyte. When the negative electrode 4 contains an electrolyte, due to the reasons described above, the electrolyte is preferably a solid electrolyte with high heat resistance.

[0021] As the negative electrode current collector 5, those that can be used as the negative electrode current collector of this type of battery can be used without particular limitation. The negative electrode current collector 5 is preferably a current collector having reduction resistance. In the example shown in Figure 3, as the negative electrode current collector 5, nickel foil is used.

[0022] 1(B), the positive electrode current collector 1 has a first portion 11, a second portion 12, and a third portion 13. The third portion 13 extends in the stacking direction of the cell 100-1 (the up-down direction in FIG. 1(B)) and connects the first portion 11 and the second portion 12. 1(C), the negative electrode current collector 5 has a first portion 51, a second portion 52, and a third portion 53. The third portion 53 extends in the stacking direction of the cell 100-1 (the up-down direction in FIG. 1(C)) and connects the first portion 51 and the second portion 52. As shown in Figures 1(A) and 1(B), the first insulating material 20 is disposed on the opposite side of the positive electrode 2 (the upper side in Figure 1(A)) across the first portion 11 of the positive electrode current collector 1. As shown in Figures 1(A) and 1(C), the second insulating material 30 is disposed on the opposite side of the negative electrode 4 (the lower side in Figure 1(A)) across the first portion 51 of the negative electrode current collector 5. As shown in Figures 1(A), 1(B), and 1(C), the second portion 12 of the positive electrode current collector 1 is disposed on the opposite side to the first portion 51 of the negative electrode current collector 5 across the second insulating material 30 (the lower side in Figures 1(A), 1(B), and 1(C)). The second portion 52 of the negative electrode current collector 5 is disposed on the opposite side to the first portion 11 of the positive electrode current collector 1 across the first insulating material 20 (the upper side in Figures 1(A), 1(B), and 1(C)).

[0023] As shown in Figures 1(A), 1(B), and 1(C), the third portion 13 of the positive electrode current collector 1 is disposed on the opposite side to the third portion 53 of the negative electrode current collector 5 (the right side in Figure 1(A)), across the positive electrode 2, the separator 3 containing an electrolyte, and the negative electrode 4.

[0024] As shown in Fig. 1(A), the first insulating material 20 is arranged so as not to overlap with the second insulating material 30 in the stacking direction of the unit cell 100-1 (the up-down direction in Fig. 1(A)). In other words, the position of the first insulating material 20 in the left-right direction in Fig. 1(A) and the position of the second insulating material 30 in the left-right direction in Fig. 1(A) are shifted (different). 1(A) and 1(B), the first insulating material 20 is disposed so as not to overlap with the second portion 12 of the positive electrode current collector 1 in the stacking direction of the unit cell 100-1. In other words, the position of the first insulating material 20 in the left-right direction of Fig. 1(A) is shifted (different) from the position of the second portion 12 of the positive electrode current collector 1 in the left-right direction of Fig. 1(A). 1(A) and 1(C), the second portion 52 of the negative electrode current collector 5 is disposed so as not to overlap with the second insulating material 30 in the stacking direction of the unit cell 100-1. In other words, the position of the second portion 52 of the negative electrode current collector 5 in the left-right direction of Fig. 1(A) is shifted (different) from the position of the second insulating material 30 in the left-right direction of Fig. 1(A). 1(A), 1(B), and 1(C), the second portion 52 of the negative electrode current collector 5 is disposed so as not to overlap with the second portion 12 of the positive electrode current collector 1 in the stacking direction of the unit cell 100-1. In other words, the position of the second portion 52 of the negative electrode current collector 5 in the left-right direction of Fig. 1(A) is shifted (different) from the position of the second portion 12 of the positive electrode current collector 1 in the left-right direction of Fig. 1(A). In the example shown in Figs. 1 to 3, the thickness of each of the cells 100-1 and 100-2 in the stacking direction is, for example, 0.1 to 2 mm. As a result, in the example shown in Figures 1 to 3, the second portion 12 of the positive electrode collector 1 of the single cell 100-1 and the first portion 11 of the positive electrode collector 1 of the single cell 100-2 are abutted against each other, and the first portion 51 of the negative electrode collector 5 of the single cell 100-1 and the second portion 52 of the negative electrode collector 5 of the single cell 100-2 are abutted against each other, thereby stacking the single cells 100-1 and 100-2 and reducing the dimension of the stacked battery 100 in the stacking direction.

[0025] In the example shown in FIGS. 1 to 3, by stacking the unit cells 100-1 and 100-2 in this manner, the unit cells 100-1 and 100-2 can be easily connected in parallel.

[0026] <Second embodiment> The stacked battery 100 of the second embodiment is configured similarly to the stacked battery 100 of the above-described first embodiment, except for the points that will be described later.

[0027] Fig. 4 is a diagram that shows an example of cells 100-1 and 100-2 included in the stacked battery 100 of the second embodiment. In detail, Fig. 4(A) is a diagram that shows the cell 100-1 as viewed from the cell 100-2 side in the stacking direction of the stacked battery 100 of the second embodiment, and Fig. 4(B) is a diagram that shows the cell 100-2 as viewed from the cell 100-1 side in the stacking direction of the stacked battery 100 of the second embodiment. As shown in Figures 2 and 4, when the second portion 12 of the positive electrode collector 1 of the single battery 100-1 and the first portion 11 of the positive electrode collector 1 of the single battery 100-2 are abutted against each other to stack the single batteries 100-1 and 100-2, the shape of the second portion 12 of the positive electrode collector 1 of the single battery 100-1 shown in Figures 2(A) and 4(A) can be set to any shape as long as the second portion 12 of the positive electrode collector 1 of the single battery 100-1 does not abut against either the second portion 52 of the negative electrode collector 5 of the single battery 100-2 or the first insulating material 20. Furthermore, when stacking the single cells 100-1 and 100-2 by abutting the first portion 51 of the negative electrode collector 5 of the single cell 100-1 with the second portion 52 of the negative electrode collector 5 of the single cell 100-2, as long as the second portion 52 of the negative electrode collector 5 of the single cell 100-2 does not abut either the second portion 12 of the positive electrode collector 1 of the single cell 100-1 or the second insulating material 30, the second portion 52 of the negative electrode collector 5 of the single cell 100-2 can be set to any shape of the shapes shown in Figures 2(B) and 4(B).

[0028] [Example] 5 to 8 are diagrams for explaining the manufacturing process of the laminated battery 100 of the embodiment. In detail, Fig. 5(A) is a cross-sectional view of an assembly of a positive electrode 2, a separator 3, and a negative electrode 4 constituting a part of the laminated battery 100 of the embodiment, and Fig. 5(B) is a view of the assembly shown in Fig. 5(A) seen from above in Fig. 5(A). Fig. 6(A) is a cross-sectional view of an assembly in a state in which a positive electrode current collector 1, a negative electrode current collector 5, and an insulating material (sealing material) 40 are added to the assembly shown in Fig. 5(A), and Fig. 6(B) is a view of the assembly shown in Fig. 6(A) seen from above in Fig. 6(A). Fig. 7(A) is a cross-sectional view of a single cell 100-1 configured by winding the second part 12 and the third part 13 of the positive electrode current collector 1 and the second part 52 and the third part 53 of the negative electrode current collector 5 of the assembly shown in Fig. 6(A) around the positive electrode 2, the separator 3, and the negative electrode 4 via the first insulating material 20 and the second insulating material 30, and Fig. 7(B) is a view of the single cell 100-1 shown in Fig. 7(A) as seen from the top of Fig. 7(A). Fig. 8 is a cross-sectional view of a stacked battery 100 configured by stacking the single cell 100-1 shown in Fig. 7(A) and a single cell 100-2 configured similarly to the single cell 100-1. Fig. 9 is a diagram showing a comparison between the cell capacity of the single cell 100-1, the cell capacity of the single cell 100-2, and the cell capacity of the stacked battery 100.

[0029] In the examples shown in Figs. 5 to 9, a mixture of LiNiCoMn, SE (LiI-LiBr-Li2S-P2S5), VGCF and SBR was used as the positive electrode material constituting the positive electrode 2. A mixture of graphite, SE (LiI-LiBr-Li2S-P2S5), VGCF and SBR was used as the negative electrode material constituting the negative electrode 4. A mixture of SE and SBR was used as the material constituting the separator 3. PP film was used as the first insulating material 20, the second insulating material 30 and the insulating material (sealing material) 40. Aluminum foil was used as the positive electrode current collector 1. Nickel foil was used as the negative electrode current collector 5. In the state shown in Figures 6(A) and 6(B), heating was performed at 160°C for 1 minute, and the positive electrode 2, separator 3, and negative electrode 4 located between the positive electrode collector 1 and the negative electrode collector 5 were sealed with an insulating material (sealing material) 40. In the state shown in Figures 7(A) and 7(B), the second portion 12 and the third portion 13 of the positive electrode current collector 1 and the second portion 52 and the third portion 53 of the negative electrode current collector 5 are wrapped around the positive electrode 2, the separator 3, the negative electrode 4, and the insulating material (sealing material) 40, and heated to 160°C for 1 minute, and then sealed with the first insulating material 20 and the second insulating material 30.

[0030] The single battery 100-1 shown in Figures 7(A) and 7(B) is constructed by laminating a positive electrode collector 1, a positive electrode 2, a separator 3 containing an electrolyte, a negative electrode 4, and a negative electrode collector 5 in this order, and sealing the electrode assembly 10 with the positive electrode collector 1, the negative electrode collector 5, a first insulating material 20, and a second insulating material 30.

[0031] In the state shown in FIG. 8, the second insulating material 30 of the single battery 100-1 and the first insulating material 20 of the single battery 100-2 were joined by heating at 160° C. for one minute, thereby ensuring electrical insulation between the second portion 12 of the positive electrode collector 1 of the single battery 100-1 and the second portion 52 of the negative electrode collector 5 of the single battery 100-2.

[0032] The stacked battery 100 shown in FIG. 8 is constructed by wrapping the second portion 12 of the positive electrode current collector 1 around the first portion 51 of the negative electrode current collector 5 with the second insulating material 30 interposed therebetween, and wrapping the second portion 52 of the negative electrode current collector 5 around the first portion 11 of the positive electrode current collector 1 with the first insulating material 20 interposed therebetween, so that the positive electrode current collector 1 and the negative electrode current collector 5 are in contact with each other when the single cells 100-1 and 100-2 are stacked.

[0033] The charge / discharge evaluation of the unit cell 100-1 and the unit cell 100-2 was carried out under the following conditions. 4.0~3.0V 0.6mA / cm 2 25℃

[0034] The stacked battery 100 formed by stacking the unit cells 100-1 and 100-2 was charged and discharged under the following conditions. 4.0~3.0V 1.2mA / cm2 25℃

[0035] The CC (Constant Current) discharge capacities of the unit cells 100-1, 100-2, and the stacked battery 100 were as shown in Fig. 9. It was confirmed that parallel capacity (capacity of unit cells 100-1 + capacity of unit cells 100-2) can be achieved simply by stacking the unit cells 100-1 and 100-2.

[0036] As described above, the embodiment of the stacked battery of the present disclosure has been described with reference to the drawings, but the stacked battery of the present disclosure is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present disclosure. The configurations of the examples of the above-described embodiment may be appropriately combined. [Explanation of symbols]

[0037] 100 stacked battery 100-1 Cell 100-2 Cell 10 Electrode body 1 Positive electrode current collector 11 Part 1 12 Part 2 13 Part 3 2 Positive electrode 3. Separator 4 Negative electrode 5 Negative electrode current collector 51 Part 1 52 Part 2 53 Part 3 20 First insulation material 30 Second insulation material

Claims

1. A stacked battery in which unit cells are stacked, each unit cell having an electrode assembly in which a positive electrode current collector, a positive electrode, an electrolyte, a negative electrode, and a negative electrode current collector are stacked in this order, a first insulating material arranged on an opposite side of the positive electrode across a first portion of the positive electrode current collector, and a second insulating material arranged on the opposite side of the negative electrode across a first portion of the negative electrode current collector, the positive electrode current collector has a first portion of the positive electrode current collector, a second portion of the positive electrode current collector, and a third portion of the positive electrode current collector extending in a stacking direction of the unit cells and connecting the first portion of the positive electrode current collector and the second portion of the positive electrode current collector, the second portion of the positive electrode current collector is disposed on the opposite side of the first portion of the negative electrode current collector across the second insulating material; the negative electrode current collector has a first portion of the negative electrode current collector, a second portion of the negative electrode current collector, and a third portion of the negative electrode current collector extending in the stacking direction and connecting the first portion of the negative electrode current collector and the second portion of the negative electrode current collector, the second portion of the negative electrode current collector is disposed on the opposite side of the first portion of the positive electrode current collector across the first insulating material; the first insulating material is disposed so as not to overlap with either the second insulating material or the second portion of the positive electrode current collector in the stacking direction; the second portion of the negative electrode current collector is disposed so as not to overlap with either the second insulating material or the second portion of the positive electrode current collector in the stacking direction.

2. The laminated battery according to claim 1 , wherein the electrolyte is a solid electrolyte.

3. 2. The stacked battery according to claim 1, wherein the thickness of the unit cell is 0.1 to 2 mm.

4. 2. The laminated battery according to claim 1, wherein the third portion of the positive electrode current collector is disposed on an opposite side to the third portion of the negative electrode current collector across the positive electrode, the electrolyte, and the negative electrode.

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