Battery

Abstract

A battery includes an electrode laminate in which end surface current collectors are disposed on both surfaces of the electrode laminate in a lamination direction, an internal current collector is laminated inside the electrode laminate, the internal current collector has a connection portion drawn out from a side surface of the electrode laminate, and the connection portion extends in the lamination direction along the side surface of the electrode laminate. And a second electrode disposed on the same surface as at least one of the end-surface current collectors.

Description

Technical Field

[0001] The present application relates to batteries. Background Art

[0002] Japanese Patent Publication No. 2019-53845 discloses a collector plate configuration structure for a bipolar battery, wherein a voltage monitoring terminal (collector plate) extends along the stacking direction on the outer surface of a side wall sealing material or between a battery cell stack and a side wall sealing material, and its end is configured on the upper surface of an upper wall sealing material. According to Japanese Patent Publication No. 2019-53845, it is recorded that by configuring the voltage monitoring terminal on the upper surface of the upper wall sealing material, the exclusive area of ​​the voltage monitoring terminal in the side surface of the cell can be suppressed. Summary of the invention

[0003] However, in the current collector plate arrangement structure of Japanese Patent Application Laid-Open No. 2019-53845, an exterior member having a through hole for leading the voltage monitoring terminal to the outside is required, and there are limitations in the structure of the exterior member.

[0004] Therefore, in view of the above circumstances, a main object of the present disclosure is to provide a battery capable of improving structural efficiency with a simple structure.

[0005] The present disclosure provides at least the following solutions.

[0006] The first scheme provides a battery, including an electrode stack, wherein end face collectors are arranged on both sides of the electrode stack in the stacking direction, and an internal collector is stacked inside the electrode stack, and the internal collector has a connecting portion led out from the side of the electrode stack, and the connecting portion extends along the side of the electrode stack in the stacking direction and is arranged on the same surface as at least one of the end face collectors.

[0007] Aspect 2 In the battery of aspect 1, a plurality of internal current collectors are stacked inside the electrode stack, and the connection portions drawn out from the plurality of internal current collectors are arranged at positions not overlapping each other when viewed in the stacking direction.

[0008] A third aspect is the battery of the first aspect or the second aspect, wherein the connection portion is disposed on at least one of the end surface current collectors via an end surface insulating layer, and the end surface insulating layer insulates at least one of the connection portion and the end surface current collector.

[0009] The fourth scheme is a battery of any one of the first to third schemes, when a portion of a connecting portion extending along the side surface of an electrode stack in a stacking direction is set as an extended portion, a side insulating layer is arranged on at least one of the extended portion and the side surface of the electrode stack, and the connecting portion and the side surface of the electrode stack are insulated by the side insulating layer.

[0010] According to the battery of the present disclosure, it is possible to improve structural efficiency with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and appended hereto:

[0012] Figure 1 is a top view of the battery 100 .

[0013] Figure 2 is from Figure 1 A front view of the battery 100 as viewed from the direction of II.

[0014] Figure 3 is from Figure 1 A side view of the battery 100 as viewed from the direction of III.

[0015] Figure 4A It is a top view of the internal current collector 20 .

[0016] Figure 4B This diagram shows a plurality of internal current collectors 20 in order to explain the differences in the positions and lengths of the connecting portions 22 .

[0017] Figure 5 2 is a cross-sectional view of an electrode stack 50 as an example. DETAILED DESCRIPTION

[0018] The battery of the present disclosure is described using a battery 100 as one embodiment.

[0019] Figure 1 A top view of the battery 100 is shown. Figure 2 Shown from Figure 1 Front view viewed from the direction of II. Figure 3 Shown from Figure 1 A side view of the battery 100 as viewed from the direction of III.

[0020] The battery 100 includes an electrode stack 50 .

[0021] <Electrode Laminate 50>

[0022] The electrode stack 50 is a stack having a rectangular shape when viewed in the stacking direction, and includes a collector (a positive electrode collector and a negative electrode collector), a positive electrode layer, a negative electrode layer, and an electrolyte layer. In the electrode stack 50, the number of stacking layers of each layer is not particularly limited and can be appropriately set according to the purpose. The stacking method of the electrode stack 50 is not particularly limited, and it can be either a monopolar type or a bipolar type. The electrode stack 50 can be either a liquid battery or a solid battery. The electrode stack 50 can be either a lithium ion battery, a sodium ion battery, or a nickel-hydrogen battery, etc. The electrode stack 50 can be either a primary battery or a secondary battery.

[0023] (Material of Electrode Stack 50)

[0024] Typical examples are given to explain the materials of the layers constituting the electrode stack 50. However, the materials of the layers constituting the electrode stack 50 are not limited thereto.

[0025] The current collector is a sheet-shaped conductive component. As the current collector, for example, metal foils of stainless steel, iron, copper, aluminum, titanium, nickel, etc. can be cited. The metal foil can also be composed of an alloy containing two or more of these metals. In addition, the metal foil can also be subjected to a predetermined surface treatment such as plating. The current collector can also be composed of a plurality of metal foils. In this case, the metal foils can be joined with an adhesive or the like, or by stamping or the like. The shape of the current collector can be rectangular. The thickness of the current collector is not particularly limited, for example, 1 μm to 1 mm.

[0026] The positive electrode layer contains at least a positive electrode active material. The positive electrode active material is not particularly limited and can be appropriately selected from any material according to the intended battery performance. For example, composite oxides, metallic lithium, and sulfur can be cited. In the composition of the composite oxide, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum and lithium are included. As an example of a composite oxide, olivine-type lithium iron phosphate (LiFePO4) can be cited.

[0027] The positive electrode layer may also contain a conductive auxiliary agent. The conductive auxiliary agent is not particularly limited and can be appropriately selected from any material according to the desired battery performance. For example, carbon materials such as acetylene black, carbon black, and graphite can be cited.

[0028] The positive electrode layer may also contain an adhesive. The adhesive is not particularly limited and may be appropriately selected from any material according to the desired battery performance. For example, rubber-based resins, fluoride-based resins, etc. may be cited.

[0029] The positive electrode layer may also contain a solid electrolyte. The solid electrolyte is not particularly limited and can be appropriately selected from any material according to the desired battery performance. For example, oxide solid electrolytes, sulfide solid electrolytes, etc. can be cited.

[0030] The positive electrode layer may be rectangular in shape. The thickness of the positive electrode layer is not particularly limited, and may be, for example, in the range of 1 μm to 1 mm. The area of ​​the positive electrode layer may also be smaller than that of the negative electrode layer. The content of each material in the positive electrode layer is not particularly limited, and may be appropriately set according to the intended battery performance. In addition, the positive electrode layer may also contain materials other than the above-mentioned materials.

[0031] The negative electrode layer contains a negative electrode active material. The negative electrode active material is not particularly limited and can be appropriately selected from any material according to the desired battery performance. For example, carbon materials such as graphite, artificial graphite, hard carbon, and soft carbon, metal compounds, elements that can be alloyed with lithium, or compounds thereof, etc. Examples of elements that can be alloyed with lithium include silicon and tin.

[0032] The negative electrode layer may also contain a conductive auxiliary agent. The conductive auxiliary agent is not particularly limited and can be appropriately selected from any material according to the intended battery performance. For example, it can be appropriately selected from conductive auxiliary agents applicable to the positive electrode layer.

[0033] The negative electrode layer may also contain an adhesive. The adhesive is not particularly limited and may be appropriately selected from any material according to the intended battery performance. For example, it may be appropriately selected from adhesives applicable to the positive electrode layer.

[0034] The negative electrode layer may also contain a solid electrolyte. The solid electrolyte is not particularly limited and can be appropriately selected from any material according to the desired battery performance. For example, it can be appropriately selected from solid electrolytes that can be applied to the positive electrode layer.

[0035] The negative electrode layer may be rectangular in shape. The thickness of the negative electrode layer is not particularly limited, and is, for example, in the range of 1 μm to 1 mm. From the perspective of increasing output, the area of ​​the negative electrode layer may be larger than that of the positive electrode layer. The content of each material in the negative electrode layer is not particularly limited and may be appropriately set according to the intended battery performance. In addition, the negative electrode layer may also contain materials other than the above-mentioned materials.

[0036] In the case where the electrolyte layer is a liquid electrolyte layer, the electrolyte layer includes a separator and an electrolyte. The separator is mainly a porous sheet of a polyolefin system. The electrolyte is obtained by dissolving a supporting salt in a non-aqueous solvent. As non-aqueous solvents, carbonates, ethers, esters, etc. can be cited. As supporting salts, for example, LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), etc. can be cited.

[0037] When the electrolyte layer is a solid electrolyte layer, the electrolyte layer contains a solid electrolyte. In addition, the solid electrolyte layer may also contain a binder. The solid electrolyte and the binder can be appropriately selected from the above-mentioned solid electrolytes and binders.

[0038] The electrolyte layer may be in a rectangular shape. The thickness of the electrolyte layer is not particularly limited, and is, for example, in the range of 1 μm to 1 mm.

[0039] (End surface current collectors 11, 12, internal current collector 20)

[0040] like Figure 1 to Figure 3 As described above, the electrode stack 50 has current collectors (sometimes referred to as "end surface current collectors 11, 12" in this specification) disposed on both sides in the stacking direction. In addition, the electrode stack 50 has current collectors (sometimes referred to as "internal current collectors 20" in this specification) stacked inside.

[0041] The end surface current collectors 11 and 12 are respectively arranged on the end surfaces of both sides of the stacking direction of the electrode stack 50. The end surface current collectors 11 and 12 can be either positive electrode current collectors or negative electrode current collectors. In addition, the end surface current collectors 11 and 12 can be either the same type of current collectors or different types of current collectors. Typically, the end surface current collectors 11 and 12 are different types of current collectors.

[0042] The internal current collector 20 is stacked inside the electrode stack 50. The number of the internal current collectors 20 is not particularly limited and can be appropriately set according to the purpose. Figure 1 to Figure 3 In the embodiment, a plurality of internal current collectors 20 (a total of 8) are arranged inside the electrode stack 50. The internal current collector 20 may be a positive electrode current collector or a negative electrode current collector. In addition, the internal current collector 20 may be a current collector of the same type or a current collector of a different type. However, the internal current collector 20 has the function of providing battery information to the outside as described later, so it may be composed entirely of the same type of current collector (preferably a positive electrode current collector). In addition, the electrode stack 50 may also have a common current collector other than the internal current collector 20 inside it.

[0043] The internal current collector 20 is different from other current collectors in that it has a connection portion 22 extending from the side surface of the electrode stack 50. Figure 4A FIG. 2 shows a top view of the internal current collector 20. Figure 4B In order to explain the difference in the position of the connection portion 22 , a plurality of internal current collectors 20 are shown.

[0044] like Figure 4AAs shown, the internal current collector 20 includes a main body 21 and a connecting portion 22. The main body 21 is a portion that is stacked inside the electrode stack 50 and functions as a current collector. Therefore, a positive electrode layer or a negative electrode layer is stacked on the main body 21. The main body 21 has a rectangular shape. In contrast, the connecting portion 22 is a portion for providing battery information (voltage, current, etc.) to the outside, and has a long and thin strip shape. The connecting portion 22 is used, for example, as a voltage monitoring line. As shown in FIG. Figure 1 to Figure 3 As shown, the connecting portion 22 has a form of being led out from the side surface 50a of the electrode stack 50, and the led out connecting portion 22 is bent in the stacking direction. Then, the connecting portion 22 is further bent, and its end is arranged on the same surface as the end face current collector 11. In this way, the connecting portion 22 is characterized in that it extends along the side surface 50a of the electrode stack 50 in the stacking direction and is arranged on the same surface as the end face current collector 11.

[0045] In previous batteries, the connection portion that functions as a voltage monitoring line has a form that is only led out in the side direction. In contrast, in the battery 100, the connection portion 22 has a portion (the extension portion 23 described later) that extends in the stacking direction along the side 50a of the electrode stack 50, thereby reducing the area occupied by the connection portion 22 in the battery 100 as a whole. In addition, in Japanese Patent Application Laid-Open No. 2019-53845, an exterior component having a through hole for leading the voltage monitoring terminal to the outside is required, and there are restrictions on the structure of the exterior component. In contrast, in the battery 100, the connection portion 22 (the end portion 24 described later) is arranged on the same surface as the end face current collector 11, thereby being able to improve the structural efficiency with a simple structure.

[0046] Here, the portion of the connecting portion 22 drawn out from the side surface of the electrode stack 50 and extending in the stacking direction along the side surface 50 a is referred to as the extending portion 23 , and the portion arranged on the same surface as the end surface current collector 11 is referred to as the end portion 24 .

[0047] like Figure 4B As shown, the position of the connection portion 22 in the internal current collector 20 is not particularly limited and may be as shown in FIG. Figure 1 , Figure 2 As shown in FIG. 1 , the connecting portions 22 drawn from the plurality of internal current collectors 20 can be arranged at positions where they do not overlap each other when viewed in the stacking direction. This can suppress contact between the connecting portions 22 and simplify the battery structure. Figure 4B As shown, the length of the connecting portion 22 is arbitrarily set in accordance with the position of the end portion 24 .

[0048] Here, "the connection portion 22 is arranged on the same surface as the end surface current collector 11" is further explained. Figure 1 , Figure 3As shown, the end 24 of the connection portion 22 is arranged on the end face collector 11 via the end face insulating layer 30. Therefore, strictly speaking, it cannot be said that the end 24 of the connection portion 22 is arranged on the same surface as the end face collector 11. However, since the end face insulating layer 30 is a very thin layer, from the point of view of use, it can be said that they are arranged on the same surface. Therefore, "the connection portion 22 is arranged on the same surface as the end face collector 11" does not strictly mean that the end 24 of the connection portion 22 is arranged on the same surface as the end face collector 11, but from the point of view of use, it means that the end 24 of the connection portion 22 is arranged on the same surface as the end face collector 11.

[0049] In addition, in the electrode stack 50, the connection portion 22 is arranged on the same surface as the end face current collector 11, but the present disclosure is not limited to this. The connection portion 22 may also be arranged on the same surface as the end face current collector 12. In addition, a part of the plurality of connection portions 22 may be arranged on the same surface as the end face current collector 11, and the remaining part may be arranged on the same surface as the end face current collector 12. Therefore, the connection portion 22 may extend along the side surface 50a of the electrode stack 50 in the stacking direction and be arranged on the same surface as at least one of the end face current collectors 11 and 12.

[0050] (Stacking Method of Electrode Stack 50)

[0051] As described above, the electrode stack 50 is a stack including a current collector, a positive electrode layer, an electrolyte layer, and a negative electrode layer, and end current collectors 11 and 12 are stacked on both sides of the electrode stack 50 in the stacking direction, and a plurality of internal current collectors 20 are provided therein. Other structures are not particularly limited. Figure 5 A cross-sectional view of an electrode stack 50 is shown as an example. Figure 5 The electrode stack 50 shown is an electrode stack for a bipolar lithium ion secondary battery.

[0052] like Figure 5 As shown, the electrode stack 50 is a structure in which a plurality of electrode bodies 56 are stacked. In the electrode stack 50, the number of electrode bodies 56 is not particularly limited and can be appropriately set according to the purpose.

[0053] The electrode body 56 includes a positive electrode collector 51, a negative electrode collector 52, a positive electrode layer 53, a negative electrode layer 54, and an electrolyte layer 55. The electrode body 56 is formed by overlapping the negative electrode layer 54 disposed on the upper surface of the negative electrode collector 52 and the positive electrode layer 53 disposed on the lower surface of the positive electrode collector 51 with the electrolyte layer 55 interposed therebetween. Then, a plurality of electrode bodies 56 are stacked in series to form an electrode stack 50.

[0054] Here, the positive electrode collector 51 disposed on one side of the stacking direction of the electrode stack 50 corresponds to the end face positive electrode collector 11, and the negative electrode collector 52 disposed on the other side of the stacking direction corresponds to the end face negative electrode collector 12. In addition, the positive electrode collector 51 or the negative electrode collector 52 contained in the electrode stack 50 corresponds to the internal collector 20. Figure 5 In the embodiment of the present invention, the positive electrode current collector 51 included in the electrode stack 50 is referred to as the internal current collector 20 .

[0055] (End surface insulation layer 30)

[0056] The electrode stack 50 has an end face insulating layer 30. The end face insulating layer 30 is arranged on a portion of the end face current collector 11. Then, the connection portion 22 (end portion 24) is arranged on the end face current collector 11 via the end face insulating layer 30, and the end face insulating layer 30 is used to insulate the end portion 24 and the end face current collector 11. In this way, the end face insulating layer 30 is arranged between the end portion 24 and the end face current collector 11, and has the function of insulating them. Therefore, the end face insulating layer 30 only needs to be arranged on at least a portion of the end face current collector 11. The end face insulating layer 30 can also be arranged on the entire end face current collector 11.

[0057] The material of the end face insulating layer 30 is not particularly limited, and for example, polyimide, polypropylene, polyethylene, polyvinyl chloride, polytetrafluoroethylene, etc. can be cited. The thickness of the end face insulating layer 30 is not particularly limited, and for example, it is 5μm to 300μm. The configuration method of the end face insulating layer 30 is not particularly limited, and for example, a resin tape can be attached to the end face positive electrode collector 11. In addition, a resin sheet can also be configured between the end face positive electrode collector 11 and the end 24 of the connecting portion 22. Alternatively, a resin material can also be coated on the end face positive electrode collector 11.

[0058] In addition, the end surface insulating layer 30 may be disposed at the end portion 24. Even if the end surface insulating layer 30 is disposed at the end portion 24, the end portion 24 and the end surface current collector 11 can be insulated by the end surface insulating layer 30. Therefore, the end surface insulating layer 30 may be disposed between the end portion 24 and the end surface current collector 11.

[0059] (Side insulation layer 40)

[0060] The electrode stack 50 has a side insulating layer 40. The side insulating layer 40 is arranged on the side 50a of the electrode stack 50. Then, the side insulating layer 40 is used to insulate the connecting portion 22 (extending portion 23) and the side 50a of the electrode stack 50. In this way, the side insulating layer 40 is arranged on the side 50a, and has the function of insulating the extending portion 23 and the side 50a. Therefore, the side insulating layer 40 can be arranged on at least a part of the side 50a. The side insulating layer 40 can also be arranged on the entire side 50a.

[0061] The material of the side insulating layer 40 is not particularly limited, and examples thereof include polyimide, polypropylene, polyethylene, polyvinyl chloride, polytetrafluoroethylene, and the like. The thickness of the side insulating layer 40 is not particularly limited, and for example, is 5 μm to 300 μm. The configuration method of the side insulating layer 40 is not particularly limited, and for example, a resin tape may be attached to the side 50 a of the electrode stack 50. In addition, a resin sheet may be disposed between the side 50 a of the electrode stack 50 and the extension 23 of the connection portion 22. Alternatively, a resin material may be applied to the side 50 a of the electrode stack 50.

[0062] In addition, the side insulating layer 40 may be disposed on the extension portion 23. Even if the side insulating layer 40 is disposed on the extension portion 23, the extension portion 23 and the side surface 50a of the electrode stack 50 can be insulated by the side insulating layer 40. Therefore, the side insulating layer 40 may be disposed on at least one of the extension portion 23 and the side surface 50a of the electrode stack 50.

[0063] (Battery 100)

[0064] The battery 100 may include an outer casing that accommodates the electrode stack 50 . In addition, the battery 100 may include electrode terminals connected to the electrode stack 50 , or may include connection terminals connected to the connection portions 22 .

[0065] The battery of the present disclosure has been described above using one embodiment. According to the battery of the present disclosure, an exterior member having a through hole is not required, and the connection portion is arranged on the same surface as the end surface current collector, so the structural efficiency can be improved with a simple structure.

Claims

1. A battery comprising an electrode stack, wherein: End surface current collectors are arranged on both sides of the electrode stack in the stacking direction. An internal current collector is stacked inside the electrode stack. The internal current collector has a connection portion extending from a side surface of the electrode stack. The connecting portion extends in the stacking direction along the side surface of the electrode stack and is arranged on the same surface as at least one of the end surface current collectors.

2. The battery according to claim 1, wherein A plurality of the internal current collectors are stacked inside the electrode stack. The connection portions drawn out from the plurality of internal current collectors are arranged at positions not overlapping each other when viewed in the stacking direction.

3. The battery according to claim 1 or 2, wherein: The connecting portion is arranged on at least one of the end surface current collectors via an end surface insulating layer. At least one of the connection portion and the end surface current collector is insulated by the end surface insulating layer.

4. The battery according to claim 1 or 2, wherein: When a portion of the connecting portion extending in the stacking direction along the side surface of the electrode stack is defined as an extended portion, A side insulating layer is disposed on at least one of the side surfaces of the extension portion and the electrode stack. The connecting portion and the side surfaces of the electrode stack are insulated by the side surface insulating layer.

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