All-solid-state batteries and all-solid-state battery modules

Abstract

To provide an all-solid battery cell that can improve the space efficiency in an internal space.SOLUTION: An all-solid battery cell 1 includes an electrode multilayer body 10 including first to third unit multilayer bodies 20a to 20c. The first to third unit multilayer bodies 20a to 20c include first to third positive electrodes 30a to 30c including a positive electrode current collector 31 in which a positive electrode active material layer 32 is formed, first to third negative electrodes 60a to 60c including a negative electrode current collector 61 in which a negative electrode active material layer 63 is formed, and first to third bipolar electrodes 50a to 50c provided between the positive and negative electrodes. The first to third unit multilayer bodies are stacked so that the positive electrodes are overlapped with each other and the negative electrodes are overlapped with each other. All the positive electrodes are electrically connected to each other through the positive electrode current collector and all the negative electrodes are electrically connected to each other through the negative electrode current collector.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an all-solid-state battery and an all-solid-state battery module.

Background Art

[0002] A secondary battery includes a normal positive electrode having a positive electrode formed on both surfaces, a normal negative electrode having a negative electrode formed on both surfaces, and a bipolar electrode disposed therebetween, which has a positive electrode formed on one surface and a negative electrode formed on the other surface (see Patent Document 1).

[0003] In such a secondary battery, wiring is drawn out from the normal positive electrode and the normal negative electrode in a direction perpendicular to the stacking direction of the electrode stack, and the drawn wiring is welded to the positive electrode tab and the negative electrode tab (see Fig. 12 of Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] In the secondary battery as described above, a plurality of current collecting wirings are drawn out from the plurality of normal positive electrodes and the plurality of normal negative electrodes in a direction perpendicular to the stacking direction of the electrode stack, which requires a space for drawing out the wirings inside the secondary battery, leading to the problem that the internal space of the secondary battery cannot be utilized efficiently.

[0006] The problem to be solved by the present invention is to provide an all-solid-state battery and an all-solid-state battery module that can improve the space efficiency in the internal space.

Means for Solving the Problems

[0007] The present invention solves the above problem by stacking an electrode stack in which three or more odd-numbered unit stacks, each including positive and negative electrodes and a bipolar electrode provided between the positive and negative electrodes, such that the positive electrodes overlap each other and the negative electrodes overlap each other, and by electrically connecting all the positive electrodes via a positive electrode current collector and all the negative electrodes via a negative electrode current collector. [Effects of the Invention]

[0008] According to the present invention, since all positive electrodes are electrically connected via positive electrode current collectors and all negative electrodes are electrically connected via negative electrode current collectors, current can be collected from both end faces in the stacking direction of the electrode stack, thereby improving space efficiency. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view showing an example of an all-solid-state battery cell in an embodiment of the present invention. [Figure 2] Figure 2 is an exploded cross-sectional view of the electrode stack of an all-solid-state battery cell in an embodiment of the present invention. [Figure 3] Figure 3 is a plan view showing an example of an electrode stack of an all-solid-state battery cell in an embodiment of the present invention. [Figure 4] Figure 4 is a cross-sectional view showing a modified example of the positive and negative electrode current collector in an embodiment of the present invention. [Figure 5] Figure 5 is a side view showing an example of an all-solid-state battery module in an embodiment of the present invention. [Modes for carrying out the invention]

[0010] A solid-state battery cell 1 according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a cross-sectional view showing an example of a solid-state battery cell 1 in this embodiment, Figure 2 is an exploded cross-sectional view of the electrode stack 10 of the solid-state battery cell 1 in this embodiment, and Figure 3 is a plan view showing an example of the electrode stack 10 of the solid-state battery cell 1 in this embodiment.

[0011] As shown in Figure 1, the all-solid-state battery cell 1 in this embodiment comprises an electrode stack 10, a positive electrode tab 35, a negative electrode tab 65, and an outer casing 70. The positive electrode tab 35 in this embodiment corresponds to an example of the "first tab lead" in the present invention, and the negative electrode tab 65 in this embodiment corresponds to an example of the "second tab lead" in the present invention.

[0012] The electrode stack 10 is a power generation element and includes three or more odd-numbered (three in this example) first to third unit stacks 20a to 20c that are stacked on top of each other. In this electrode stack 10, the first to third unit stacks 20a to 20c are connected in a 2 series and 3 parallel configuration. In this embodiment, the case in which the electrode stack 10 includes the first to third unit stacks 20a to 20c is illustrated, but it is not limited to this, and the number of unit stacks included in the electrode stack 10 may be five or more odd-numbered (5, 7, 9, ...). Also, the number of positive electrode connection parts 31b and negative electrode connection parts 61b, which will be described later, will change according to the number of unit stacks.

[0013] Although the detailed structure will be described later, in this embodiment, the three unit stacks 20a to 20c are stacked such that the positive electrodes of adjacent unit stacks overlap with each other, and the negative electrodes of adjacent unit stacks overlap with each other. Therefore, the positive electrode can be placed at the upper end and the negative electrode at the lower end in the stacking direction (Z direction in the figure) of the electrode stack 10.

[0014] As shown in Figure 2, the first unit stack 20a is located at the top of the electrode stack 10. This first unit stack 20a includes a first positive electrode 30a, two solid electrolyte layers 40, a first bipolar electrode 50a, and a first negative electrode 60a.

[0015] The first unit laminate 20a includes a laminated portion LP. The laminated portion LP is the part of the first unit laminate 20a in which the first positive electrode 30a, solid electrolyte layers 40, 40, first bipolar electrode 50a, and first negative electrode 60a are laminated (overlapping in direct contact). The planar shape of the laminated portion LP in this embodiment is not particularly limited, but is rectangular.

[0016] The first positive electrode 30a in the present embodiment is a monopolar positive electrode, and includes a positive electrode current collector 31 and a positive electrode active material layer 32. The positive electrode current collector 31 is a metal foil. The positive electrode current collector 31 of the first positive electrode 30a constitutes the uppermost end portion of the first unit stacked body 20a in the stacking direction (Z direction), and also constitutes the uppermost end portion of the electrode stacked body 10 in the stacking direction (Z direction). As shown in Figure 1, the upper surface of this positive electrode current collector 31 is joined to the positive electrode tab 35 by welding or the like.

[0017] As shown in Figure 2, the positive electrode current collector 31 of the first positive electrode 30a includes a positive electrode forming portion 31a, a positive electrode connecting portion 31b, and a first insulating layer 31c. The positive electrode forming portion 31a is a portion extending along the direction (XY direction in the figure) orthogonal to the stacking direction, and the positive electrode active material layer 32 is formed on the lower surface of this positive electrode forming portion 31a.

[0018] On the other hand, the positive electrode connecting portion 31b is a U-shaped portion connected to the right end of the positive electrode forming portion 31a, and this positive electrode connecting portion 31b is also connected to the positive electrode current collector 31 (described later) of the second positive electrode 30b (described later). The positive electrode connecting portion 31b in the present embodiment extends in the stacking direction so as to straddle the contact portion between the negative electrode current collector 61 of the first negative electrode 60a and the negative electrode current collector 61 of the second negative electrode 60b.

[0019] The positive electrode connecting portion 31b connects the positive electrode current collector 31 of the first positive electrode 30a and the positive electrode current collector 31 of the second positive electrode 30b, whereby the first positive electrode 30a and the second positive electrode 30b are electrically connected via the respective positive electrode current collectors 31, 31.

[0020] As shown in Figure 3, the positive electrode connecting portion 31b is provided on the first long side LS1 side of the stacked portion LP in a plan view, and extends from this first long side LS1. As in the present embodiment, since the positive electrode connecting portion 31b is provided on the first long side LS1 side of the stacked portion LP, the width of the positive electrode connecting portion 31b can be set large, so that the cross-sectional area of the positive electrode connecting portion 31b can be increased. Therefore, the electric resistance in the positive electrode connecting portion 31b can be reduced.

[0021] As shown in FIG. 2, in the present embodiment, the positive electrode current collector 31 of the first positive electrode 30a and the positive electrode current collector 31 of the second positive electrode 30b are integrally formed. More specifically, the positive electrode current collector 31 of the first positive electrode 30a and the positive electrode current collector 31 of the second positive electrode 30b are formed by bending a single metal foil into a U-shape.

[0022] A first insulating layer 31c is formed on the inner side surface of the positive electrode connection portion 31b facing the laminated portion LP. The first insulating layer 31c is not particularly limited, and a resin or the like having insulating properties can be used. This first insulating layer 31c can prevent a short circuit between the positive electrode connection portion 31b, and the first bipolar electrode 50a and the first negative electrode 60a. Note that the first insulating layer 31c does not need to be provided on the positive electrode connection portion 31b as long as it is provided between the positive electrode connection portion 31b and the laminated portion LP, and may be provided on the side surface of the laminated portion LP facing the positive electrode connection portion 31b (in this example, the side surface constituting the first long side LS1).

[0023] The positive electrode active material layer 32 is formed on the lower surface of the positive electrode current collector 31. This positive electrode active material layer 32 can be formed by applying a paste containing a positive electrode active material capable of occluding and releasing lithium ions and the like to the positive electrode current collector 31.

[0024] The solid electrolyte layer 40 is laminated on the lower surface of the positive electrode active material layer 32. As this solid electrolyte layer 40, for example, a sulfide solid electrolyte or an oxide solid electrolyte and the like can be used.

[0025] The first bipolar electrode 50a is laminated on the lower surface of the solid electrolyte layer 40. This first bipolar electrode 50a includes a bipolar current collector 51, a positive electrode active material layer 52, and a negative electrode active material layer 53.

[0026] In the first bipolar electrode 50a according to the present embodiment, the negative electrode active material layer 53 is formed on the upper surface of the bipolar current collector 51, and the positive electrode active material layer 52 is formed on the lower surface of the bipolar current collector 51.

[0027] In this embodiment, the first unit laminate 20a includes one first bipolar electrode 50a, but is not limited to this, and may include multiple first bipolar electrodes 50a.

[0028] A solid electrolyte layer 40 is laminated on the lower surface of the positive electrode active material layer 52, and a first negative electrode 60a is laminated on the lower surface of this solid electrolyte layer 40. The first negative electrode 60a is a monopolar negative electrode and includes a negative electrode current collector 61 and a negative electrode active material layer 63.

[0029] The negative electrode current collector 61 is a metal foil. In this embodiment, the negative electrode current collector 61 of the first negative electrode 60a extends along a direction perpendicular to the lamination direction (XY direction in the figure).

[0030] A negative electrode active material layer 63 is formed on the upper surface of the negative electrode current collector 61. This negative electrode active material layer 63 is in contact with the solid electrolyte layer 40. This negative electrode active material layer 63 contains a negative electrode active material, which can be a carbon-based active material, a silicon-based active material, or a metal-based active material. When a carbon-based active material or a silicon-based active material is used as the negative electrode active material, the negative electrode active material layer 63 can be formed by applying and drying a paste containing the negative electrode active material onto the negative electrode current collector 61. When a metal-based active material is used as the negative electrode active material, the negative electrode active material layer 63 can be formed by pre-forming a metal film on the negative electrode current collector 61 by vapor deposition or the like before assembling the battery. Alternatively, a negative electrode active material layer 63 made of a metal-based active material may be formed by charging after the battery is assembled. In other words, the negative electrode active material layer 63 does not exist when the battery is completed, but the negative electrode active material layer 63 may be formed when metal is deposited on the surface of the negative electrode current collector 61 during battery charging. Examples of metal active materials include alkali metals or alkali metal compounds, but more specifically, Li metal can be given as an example.

[0031] A second unit stack 20b is stacked on the lower end of the first unit stack 20a as described above. This second unit stack 20b includes a second negative electrode 60b, two solid electrolyte layers 40, 40, a second bipolar electrode, and a second positive electrode 30b.

[0032] The second negative electrode 60b is a monopolar negative electrode and includes a negative electrode current collector 61 and a negative electrode active material layer 63. This negative electrode current collector 61 is electrically connected to the negative electrode current collector 61 of the first negative electrode 60a of the first unit laminate 20a by direct contact.

[0033] The negative electrode current collector 61 of the second negative electrode 60b includes a negative electrode forming portion 61a, a negative electrode connecting portion 61b, and a second insulating layer 61c. The negative electrode forming portion 61a is a portion that extends along a direction perpendicular to the stacking direction (XY direction in the figure), and a positive electrode active material layer 62 is formed on the lower surface of this negative electrode forming portion 61a.

[0034] On the other hand, the negative electrode connection portion 61b is a U-shaped portion that connects to the left end of the negative electrode forming portion 61a, and this negative electrode connection portion 61b is also connected to the negative electrode current collector 61 (described later) of the third negative electrode 60c (described later). In this embodiment, the negative electrode connection portion 61b extends in the stacking direction so as to straddle the contact portion between the positive electrode current collector 31 of the second positive electrode 30b and the positive electrode current collector 31 of the third positive electrode 30c.

[0035] The negative electrode connection section 61b connects the negative electrode current collector 61 of the second negative electrode 60b and the negative electrode current collector 61 of the third negative electrode 60c, thereby electrically connecting the second negative electrode 60b and the third negative electrode 60c via their respective negative electrode current collectors 61, 61.

[0036] As shown in Figure 3, the negative electrode connection portion 61b is located on the second long side LS2 side of the laminated portion LP, opposite to the first long side LS1, in a plan view, and extends from this second long side LS2. As in this embodiment, by providing the negative electrode connection portion 61b on the second long side LS2 side of the laminated portion LP, the width of the negative electrode connection portion 61b can be set to be large, and thus the cross-sectional area of ​​the negative electrode connection portion 61b can be increased. Therefore, the electrical resistance of the negative electrode connection portion 61b can be reduced.

[0037] In this embodiment, the negative electrode current collector 61 of the second negative electrode 60b and the negative electrode current collector 61 of the third negative electrode 60c are integrally formed. More specifically, the negative electrode current collector 61 of the second negative electrode 60b and the negative electrode current collector 61 of the third negative electrode 60c are formed by folding a single metal foil into a U-shape.

[0038] A second insulating layer 61c is formed on the inner surface of the negative electrode connection portion 61b facing the laminated portion LP. The second insulating layer 61c is not particularly limited, but an insulating resin or the like can be used. This second insulating layer 61c prevents short circuits between the negative electrode connection portion 61b and the second bipolar electrode 5b and the second positive electrode 30b. Note that this second insulating layer 61c does not need to be provided on the negative electrode connection portion 61b as long as it is provided between the negative electrode connection portion 61b and the laminated portion LP, and may be provided on the side of the laminated portion LP facing the negative electrode connection portion 61b (in this example, the side constituting the second long side LS2).

[0039] The negative electrode active material layer 63 is formed on the lower surface of the negative electrode current collector 61. This negative electrode active material layer 63 can have the same configuration as the negative electrode active material layer 63 described above.

[0040] A solid electrolyte layer 40 is laminated on the lower surface of the negative electrode active material layer 63. A second bipolar electrode 50b is laminated on the lower surface of this solid electrolyte layer 40. This second bipolar electrode 50b has the same configuration as the first bipolar electrode 50a when inverted, and includes a bipolar current collector 51, a positive electrode active material layer 52, and a negative electrode active material layer 53.

[0041] In this second bipolar electrode 50b, a positive electrode active material layer 52 is formed on the upper surface of the bipolar current collector 51, and a negative electrode active material layer 53 is formed on the lower surface of the bipolar current collector 51.

[0042] In this embodiment, the second unit laminate 20b includes one second bipolar electrode 50b, but is not limited to this and may include multiple second bipolar electrodes 50b.

[0043] A solid electrolyte layer 40 is laminated on the lower surface of the negative electrode active material layer 53, and a second positive electrode 30b is laminated on the lower surface of this solid electrolyte layer 40. The second positive electrode 30b is a monopolar positive electrode and includes a positive electrode current collector 31 and a positive electrode active material layer 32.

[0044] The positive electrode current collector 31 of the second positive electrode 30b includes a positive electrode forming portion 31a on which the positive electrode active material layer 32 of the second unit laminate 20b is formed. Furthermore, the positive electrode current collector 31 of the second positive electrode 30b is integrally formed with the positive electrode current collector 31 of the first positive electrode 30a, and shares a positive electrode connection portion 31b with the positive electrode current collector 31 of the first positive electrode 30a. In addition, the second positive electrode 30b also shares a first insulating layer 31c with the first positive electrode 30a.

[0045] A third unit stack 20c is stacked on the lower end of the second unit stack 20b as described above. This third unit stack 20c includes a third positive electrode 30c, two solid electrolyte layers 40, a third bipolar electrode 50c, and a third negative electrode 60c.

[0046] The third positive electrode 30c is a monopolar positive electrode and includes a positive electrode current collector 31 and a positive electrode active material layer 32. This positive electrode current collector 31 is electrically connected to the positive electrode current collector 31 of the second positive electrode 30b of the second unit laminate 20b by direct contact.

[0047] A solid electrolyte layer 40 is laminated on the lower surface of the positive electrode active material layer 32, and a third bipolar electrode 50c is laminated on the lower surface of this solid electrolyte layer 40. This third bipolar electrode 50c has the same configuration as the first bipolar electrode 50a described above. In this embodiment, the third unit laminate 20c contains one third bipolar electrode 50c, but is not limited to this, and may contain multiple third bipolar electrodes 50c.

[0048] A solid electrolyte layer 40 is laminated on the lower surface of the positive electrode active material layer 52 of the third bipolar electrode 50c, and a third negative electrode 60c is laminated on the lower surface of the solid electrolyte layer 40. The third negative electrode 60c is a monopolar negative electrode and includes a negative electrode current collector 61 and a negative electrode active material layer 63.

[0049] The negative electrode current collector 61 of the third negative electrode 60c includes a negative electrode forming portion 61a on which the negative electrode active material layer 63 of the third unit laminate 20c is formed. Furthermore, the negative electrode current collector 61 of the third negative electrode 60c is integrally formed with the negative electrode current collector 61 of the second negative electrode 60b, and shares a negative electrode connection portion 61b with the negative electrode current collector 61 of the second negative electrode 60b. In addition, the third negative electrode 60c also shares a second insulating layer 61c with the second negative electrode 60b.

[0050] In the electrode stack 10 described above, as shown in Figure 1, the positive electrode current collector 31 of the first positive electrode 30a is electrically connected to the positive electrode current collector 31 of the second positive electrode 30b via the positive electrode connection part 31b. Furthermore, the positive electrode current collector 31 of the second positive electrode 30b is electrically connected to the positive electrode current collector 31 of the third positive electrode 30c by direct contact. As a result, all positive electrodes included in this electrode stack 10 are electrically connected via the positive electrode current collectors 31.

[0051] Similarly, the negative electrode current collector 61 of the first negative electrode 60a is electrically connected to the negative electrode current collector 61 of the second negative electrode 60b by direct contact. Furthermore, the negative electrode current collector 61 of the second negative electrode 60b is electrically connected to the negative electrode current collector 61 of the third negative electrode 60c via the negative electrode connection portion 61b. As a result, all negative electrodes included in this electrode stack 10 are electrically connected via the negative electrode current collectors 61.

[0052] The dashed arrows shown in Figure 1 indicate the electron transfer path E in this all-solid-state battery cell 1. In this all-solid-state battery cell 1, all positive electrodes (first to third positive electrodes 30a to 30c) and all negative electrodes (first to third negative electrodes 60a to 60c) conduct electrons via the positive and negative electrode current collectors 31 and 61, so a parallel connection of the unit stacks 20a to 20c is established, and surface current collection is possible at the upper and lower end faces of the electrode stack 10.

[0053] Therefore, the all-solid-state battery cell 1 in this embodiment can improve space efficiency. Furthermore, since the all-solid-state battery cell 1 has a structure in which a bipolar electrode is interposed between the monopolar positive electrode and the monopolar negative electrode, the cell voltage can be easily adjusted within a limited volume by adjusting the number of bipolar electrodes and the number of unit stacks within the all-solid-state battery cell 1.

[0054] Furthermore, in this embodiment, the positive electrode tab 35 can be joined to the positive electrode current collector 31 on the upper end surface of the electrode stack 10, and the negative electrode tab 65 can be joined to the negative electrode current collector 61 on the lower end surface of the electrode stack 10. In other words, the bonding area between the electrode stack 10 and the positive and negative electrode tabs 35 and 65 can be increased, thereby reducing the resistance of the all-solid-state battery cell 1.

[0055] Furthermore, in the above embodiment, the bipolar current collector 51 may be a metal foil, but it is preferable that it be a conductive elastic body. This conductive elastic body may be a conductive resin, a rubber member with a metal coating on its surface, or the like. Because the bipolar current collector 51 is elastic, even if the positive and negative electrode active material layers expand during charging and discharging of the all-solid-state battery cell 1, the bipolar current collector 51 can be compressed and absorb the thickness deformation. Therefore, it is possible to suppress the occurrence of fracture of the positive electrode connection portion 31b and the negative electrode connection portion 61b caused by changes in the thickness of the electrode laminate 10.

[0056] Figure 4 is a cross-sectional view showing modified examples of the positive and negative electrode current collectors 31 and 61 in this embodiment. From the viewpoint of suppressing the occurrence of fracture of the positive electrode connection portion 31b and the negative electrode connection portion 61b due to expansion of the electrode laminate 10, the positive electrode current collector 31 and the negative electrode current collector 61 may have shapes as shown in the modified examples in Figures 4(a) and 4(b).

[0057] As shown in Figure 4(a), the positive electrode connection portion 31b and the negative electrode connection portion 61b may be flexible. Alternatively, as shown in Figure 4(a), the positive electrode connection portion 31b and the negative electrode connection portion 61b may include folded portions. With such shapes, the positive electrode connection portion 31b and the negative electrode connection portion 61b can follow changes in the thickness of the electrode laminate 10, thereby suppressing the occurrence of fracture of the positive electrode connection portion 31b and the negative electrode connection portion 61b.

[0058] Furthermore, from the viewpoint of further reducing the resistance in the all-solid-state battery cell 1, the positive electrode current collector 31 and the negative electrode current collector 61 may be in the modified forms shown in Figures 4(c), 4(d), and 4(e).

[0059] In Figure 4(c), a conductive elastic member 39 may be provided between the positive electrode current collectors 31, 31 (in this embodiment, between the second unit stack 20b and the third unit stack 20c). The elastic member 39 is not particularly limited, but may be a conductive resin or a rubber member coated with metal on its surface. Similarly, a conductive elastic member 69 may be provided between the negative electrode current collectors 61, 61 (in this embodiment, between the first unit stack 20a and the second unit stack 20b).

[0060] By providing these elastic members 39 and 69, contact can be improved compared to when the metal foil current collectors are in direct contact with each other, thereby improving electronic conductivity. As a result, the resistance of the all-solid-state battery cell 1 can be reduced.

[0061] Furthermore, in Figure 4(d), the positive electrode current collector 31 may be extended to the outside of the outer casing 70 and used as a positive electrode tab. Similarly, the negative electrode current collector 61 may be extended to the outside of the outer casing 70 and used as a negative electrode tab.

[0062] With such positive electrode current collectors 31 and negative electrode current collectors 61, the connection between the positive electrode current collector 31 and the positive electrode tab, and the connection between the negative electrode current collector 61 and the negative electrode tab become unnecessary, thus preventing an increase in resistance at the connection points. Therefore, the resistance of the all-solid-state battery cell 1 can be reduced.

[0063] Furthermore, in Figure 4(d), all negative electrode current collectors 61 may be formed by folding a single metal foil. In particular, the negative electrode current collector 61 at the lower end of the first unit laminate 20a and the negative electrode current collector 61 at the upper end of the second unit laminate 20b, which were in direct surface contact in the above embodiment, are connected at the folded portion 61d and are in surface contact.

[0064] Thus, since all negative electrode current collectors 61 are formed by folding a single metal foil, the electronic resistance in the negative electrode current collectors 61 is reduced, and the resistance of the all-solid-state battery cell 1 can be reduced.

[0065] In this modified example, the negative electrode current collector 61 at the lower end of the second unit stack 20b and the negative electrode current collector 61 at the upper end of the third unit stack 20c are separate components. This is because, generally, the positive electrode is stacked with the positive electrode active material layer at its thickest during manufacturing, and forming a folded portion could cause the positive electrode active material layer to detach due to stress. On the other hand, the negative electrode is generally stacked in a thin state without lithium ions, so even if a folded portion 61d as described above is formed, the detachment of the negative electrode active material layer is unlikely to occur.

[0066] Figure 5 is a side view showing an example of an all-solid-state battery module 100 in this embodiment. As shown in Figure 5, the all-solid-state battery module 100 comprises a plurality of all-solid-state battery cells 1.

[0067] Multiple solid-state battery cells 1 are stacked on top of each other along the stacking direction (Z direction in the figure) of the unit stacks 20a to 20c, and are connected in series via positive and negative electrode tabs 35 and 65.

[0068] In the all-solid-state battery module 100 of this embodiment, the all-solid-state battery cells 1 can be directly joined to each other without the need for a busbar. Therefore, since no resistance is generated at the junction between the busbar and the positive and negative electrode tabs, the resistance of the all-solid-state battery module 100 can be reduced. [Explanation of Symbols]

[0069] 1… All-solid-state battery cell 10… Electrode stack LP…Laminated part LS1, LS2... Longer side 20a~20c...1st to 3rd unit laminate 30a~30c...1st~3rd positive electrode 31...Positive electrode current collector 31a...Positive electrode forming part 31b...Positive electrode connection 31c...First insulating layer 32...Cathode active material layer 35... Positive electrode tab 39...Elastic member 40...Solid electrolyte layer 50a~50c...1st to 3rd bipolar electrodes 51... Bipolar current collector 52...Cathode active material layer 53...Negative electrode active material layer 60a~60c...1st~3rd negative electrode 61...Negative electrode current collector 61a...Negative electrode forming part 61b...Negative electrode connection 61c...Second insulating layer 63...Negative electrode active material layer 65... Negative electrode tab 70... Exterior 100... All-solid-state battery module

Claims

1. A solid-state battery cell comprising an electrode stack, The electrode stack comprises three or more odd-numbered unit stacks, The aforementioned unit stack is A positive electrode comprising a positive electrode current collector having a positive electrode active material layer formed on at least one main surface, A negative electrode comprising a negative electrode current collector having a negative electrode active material layer formed on at least one main surface, The present invention includes a bipolar current collector having a positive electrode active material layer formed on one main surface and a negative electrode active material layer formed on the other main surface, and a bipolar electrode provided between the positive electrode and the negative electrode, The system includes a solid electrolyte layer provided between the positive electrode and the negative electrode, The three or more odd-numbered unit stacks are stacked such that the positive electrodes overlap each other and the negative electrodes overlap each other. All of the aforementioned positive electrodes are electrically connected via the aforementioned positive electrode current collector. All of the aforementioned negative electrodes are electrically connected via the negative electrode current collector in an all-solid-state battery cell.

2. In the all-solid-state battery cell according to claim 1, The aforementioned unit stack is A laminated portion comprising the positive electrode, the negative electrode, the bipolar electrode, and the solid electrolyte layer, The positive electrode current collector extends from the laminated portion and is connected to the positive electrode current collector of another unit laminated portion, The negative electrode current collector extends from the laminated portion and is connected to the negative electrode current collector of another unit laminated portion, A first insulating layer is provided between the laminated portion and the positive electrode connection portion, A solid-state battery cell further comprising a second insulating layer provided between the laminated portion and the negative electrode connection portion.

3. In the all-solid-state battery cell according to claim 1, The all-solid-state battery cell is A first tab lead is bonded to one end face in the stacking direction of the electrode stack, A solid-state battery cell further comprising a second tab lead bonded to the other end face in the stacking direction of the electrode stack.

4. In the all-solid-state battery cell according to claim 2, The positive electrode connection portion is either bent or folded. The negative electrode connection portion is a bent or folded all-solid-state battery cell.

5. In the all-solid-state battery cell according to claim 1, The bipolar current collector is an elastic all-solid-state battery cell.

6. In the all-solid-state battery cell according to claim 1, The electrode stack further includes a conductive elastic member provided between the unit stacks, making it an all-solid-state battery cell.

7. In the all-solid-state battery cell according to claim 1, The all-solid-state battery cell further comprises an outer casing that houses the electrode stack, The positive electrode current collector of the positive electrode located at one end in the stacking direction of the electrode stack extends from the inside of the outer casing to the outside of the outer casing. The negative electrode current collector of the negative electrode located at the other end in the stacking direction of the electrode stack is an all-solid-state battery cell that extends from the inside of the outer casing to the outside of the outer casing.

8. In the all-solid-state battery cell according to claim 2, The planar shape of the aforementioned stacked portion is rectangular. The positive electrode connection portion is provided on the first long side of the rectangle, The negative electrode connection portion is provided on the second long side, which is located opposite to the first long side, in this all-solid-state battery cell.

9. In the all-solid-state battery cell according to claim 1, The pair of negative electrode current collectors in the pair of negative electrodes that are stacked on top of each other are made of a single folded metal foil, An all-solid-state battery cell in which a pair of positive electrode current collectors in a pair of positive electrodes stacked on top of each other are composed of separate metal foils.

10. A solid-state battery module comprising a plurality of solid-state battery cells according to any one of claims 1 to 9, A solid-state battery module in which a plurality of the aforementioned solid-state battery cells are stacked on each other along the stacking direction of the unit stack and are connected in series.

Images