JP2022027200A - Power storage module - Google Patents

Abstract

To provide a power storage module that enables stable state detection while standardizing parts across a plurality of power storage cells.SOLUTION: A power storage device 1 includes a laminate 5 including a plurality of power storage cells 2, and a detection unit 50 that detects the state of the power storage cell 2. The detection unit 50 includes a voltage detection line 51 that is intervened between the other surface 20b of one power storage cell 2 and the other surface 21b of another power storage cell 2, and is connected to a first current collector 20 of the one power storage cell 2 and/or a second current collector 21 of the other power storage cell 2, and connector portions 52A and 52B for holding the voltage detection line 51 and connecting the voltage detection line 51 to the outside.SELECTED DRAWING: Figure 2

Description

The present invention relates to a power storage module.

Patent Document 1 describes a bipolar battery. In this bipolar battery, a plurality of bipolar electrodes having a positive electrode active material layer and a negative electrode active material layer provided on a current collector and a plurality of polymer solid electrolyte layers are alternately bonded to each other, and a positive electrode terminal side electrode is attached to the outermost layer. And the negative electrode terminal side electrode is arranged and configured. Each current collector is provided with a voltage measuring tab electrode for measuring the voltage of each cell. The tab electrodes for voltage measurement are arranged so that adjacent ones are not in the same position. Specifically, the tab electrodes for voltage measurement are arranged at equal intervals in the longitudinal direction of the side surface of the bipolar battery.

Japanese Unexamined Patent Publication No. 2004-87238

In the above-mentioned bipolar battery, a short circuit due to contact between the voltage measurement tab electrodes is suppressed by shifting the position across a plurality of voltage measurement tab electrodes. However, in the above-mentioned bipolar battery, it is necessary to prepare a plurality of types of current collectors in which the tab electrodes for voltage measurement are provided at different positions, and it becomes impossible to standardize the components across the plurality of storage cells.

On the other hand, for example, if a metal foil is prepared as a tab separately from the current collector and the metal foil is joined at different positions across the plurality of current collectors, the parts are common across the plurality of storage cells. It becomes possible to carry out the conversion. However, in this case, if the metal leaf is used as it is for connecting to the outside, the load applied to the metal foil is transmitted to the joint portion between the current collector and the metal foil, so that the joint portion of the joint portion is used. The condition may change and the electrical resistance may increase. That is, stable voltage detection may be difficult.

Therefore, an object of the present invention is to provide a power storage module capable of stable state detection while standardizing parts across a plurality of power storage cells.

The power storage module according to the present invention includes a laminated body including a plurality of power storage cells stacked on each other and a detection unit for detecting the state of the power storage cells, and the power storage cells include a first current collector and a first power storage cell. The first electrode including the first active material layer provided on the first surface of the current collector, the second current collector, and the second surface of the second current collector are provided and different from the first active material layer. Seen from the stacking direction of the second electrode, which includes the polar second active material layer and is laminated on the first electrode so that the second active material layer faces the first active material layer, and the first electrode and the second electrode. The laminated body includes a spacer provided between the first current collector and the second current collector so as to surround the first active material layer and the second active material layer, and the laminated body is the first storage cell. A plurality of storage cells are stacked so that the third surface on the opposite side of the first surface of the current collector and the fourth surface on the opposite side of the second surface of the second current storage cell of another storage cell face each other. The detection unit is interposed between the third surface and the fourth surface facing each other, and is connected to the first current collector and / or the second current collector. It has a connector portion for holding the detection line and connecting the detection line to the outside.

This power storage module includes a detection unit for detecting the state of the power storage cells constituting the laminated body. The detection unit includes a detection line interposed between the current collectors of the storage cells adjacent to each other. The detection line is held in the connector portion for external connection. Therefore, when detecting the state of the storage cell using this detection unit, it is not necessary to prepare current collectors having various shapes. That is, it is possible to standardize parts across a plurality of storage cells. Further, in this power storage module, since the detection line is held by the connector portion, the load applied to the detection line and the connection portion between the detection line and the current collector can be reduced. That is, stable state detection becomes possible. As described above, according to this power storage module, stable state detection is possible while standardizing parts across a plurality of power storage cells.

The power storage module according to the present invention may include a fixing portion for fixing the connector portion to the spacer. In this case, since the connector portion is fixed to the spacer, it becomes easier to absorb the load, and the load applied to the connection portion between the current collector and the detection line is further reduced.

In the power storage module according to the present invention, a sealing space is formed by a fixed portion, the spacer of the above-mentioned one storage cell, the spacer of the other storage cell, and the connector portion, and the detection line is in the sealing space. May be placed in. In this case, it is suppressed that moisture or the like infiltrates into the sealing space formed by the fixed portion, the spacers of the two adjacent storage cells, and the connector portion, and the adhesion of moisture or the like to the detection line is suppressed. To.

In the power storage module according to the present invention, the connector portion may be located outside the outer edge of the spacer when viewed from the stacking direction. In this case, since the connector portion is located outside the spacer, deterioration of battery performance due to expansion between storage cells is suppressed as compared with the case where the connector is interposed between the current collector and the spacer. ..

In the power storage module according to the present invention, the detection line may be a voltage detection line electrically connected to the first current collector and / or the second current collector. In this case, stable voltage detection is possible while standardizing parts across a plurality of storage cells.

In the power storage module according to the present invention, the detection wire includes a conductor portion and an insulating layer covering a part of the conductor portion, and a first current collector and / or a second collector in a portion exposed from the insulating layer of the conductor portion. It may be electrically connected to the current collector. In this case, the electrical insulation is improved except for the connection portion between the current collector and the detection line.

In the power storage module according to the present invention, a recess is formed in the connector portion, and the connector portion may hold the detection line so that the detection line is exposed on the inner surface of the recess. In this case, the connector portion can be configured as a female type. Alternatively, in the power storage module according to the present invention, the connector portion includes a conductive member connected to the detection line and a holding portion for holding the conductive member, and the conductive member may protrude from the holding portion. In this case, the connector portion can be configured as a male type.

In the power storage module according to the present invention, the detection line may extend so as to overlap the first active material layer and the second active material layer when viewed from the stacking direction. A restraining pressure may be applied to the portion of the current collector on which the active material layer is formed in order to ensure battery performance. In this case, the confining pressure is also applied to the connection portion between the detection line and the current collector, so that the contact between the detection line and the current collector can be reliably maintained.

In the power storage module according to the present invention, the second active material layer is formed larger than the first active material layer when viewed from the stacking direction, and the detection lines are the first active material layer and the second active material layer when viewed from the stacking direction. It may extend so as to overlap only the second active material layer of the active material layer. In this case, it is possible to more reliably detect the state of the storage cell by increasing the contact area of the detection line while suppressing the influence on the battery performance due to the intervention of the detection line.

The power storage module according to the present invention may further include a sealing portion for sealing between the spacer and the connector portion. In this case, it is possible to prevent moisture or the like from entering between the detection lines between the spacer and the connector portion.

According to the present invention, it is possible to provide a power storage module capable of stable state detection while suppressing an increase in the number of parts.

FIG. 1 is a schematic cross-sectional view showing a power storage device according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of the power storage device shown in FIG. FIG. 3 is a front view (a view when viewed from the X direction) of the portion shown in FIG. FIG. 4 is an enlarged cross-sectional view showing a part of the power storage device shown in FIG. FIG. 5 is a cross-sectional view showing a voltage detection line according to a modified example.

Hereinafter, one embodiment will be described with reference to the attached drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate description may be omitted. Further, each figure may show an orthogonal coordinate system including an X-axis, a Y-axis, and a Z-axis.
[Overall configuration of power storage device]

FIG. 1 is a schematic cross-sectional view showing a power storage device according to an embodiment. The power storage device 1 shown in FIG. 1 is a power storage module used for batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 is a secondary battery such as a nickel hydrogen secondary battery or a lithium ion secondary battery. The power storage device 1 may be an electric double layer capacitor or an all-solid-state battery. In this embodiment, a case where the power storage device 1 is a lithium ion secondary battery is illustrated.

The power storage device 1 includes a laminated body 5 in which a plurality of power storage cells 2 are stacked (stacked) in the stacking direction, and a plurality of detection units 50 provided on the stacked body 5. Here, the stacking direction of the storage cells 2 is the Z-axis direction. Each storage cell 2 includes a positive electrode (first electrode) 11, a negative electrode (second electrode) 12, a separator 13, and a spacer 14. The positive electrode 11 includes a first current collector 20 and a positive electrode active material layer (first active material layer) 22 provided on one surface (first surface) 20a of the first current collector 20. The positive electrode 11 is, for example, a rectangular electrode.

The negative electrode 12 is a negative electrode active material layer (second active material layer having a polarity different from that of the first active material layer) provided on the second current collector 21 and one surface (second surface) 21a of the second current collector 21. ) 23. The negative electrode 12 is, for example, a rectangular electrode. The negative electrode 12 is laminated on the positive electrode 11 so that the negative electrode active material layer 23 faces the positive electrode active material layer 22. In the present embodiment, the stacking direction of the positive electrode 11 and the negative electrode 12 coincides with the stacking direction of the storage cell 2 (the Z-axis direction). Hereinafter, the stacking direction of the storage cell 2 and the stacking direction of the positive electrode 11 and the negative electrode 12 may be simply referred to as “stacking direction”. In the present embodiment, both the positive electrode active material layer 22 and the negative electrode active material layer 23 are formed in a rectangular shape. The negative electrode active material layer 23 is formed to be one size larger than the positive electrode active material layer 22, and the entire formed region of the positive electrode active material layer 22 is formed of the negative electrode active material layer 23 in a plan view (when viewed from the stacking direction). It is located within the formation area.

The first current collector 20 has the other surface (third surface) 20b, which is the surface opposite to the one surface 20a. The positive electrode active material layer 22 is not formed on the other surface 20b. The second current collector 21 has the other surface (fourth surface) 21b, which is the surface opposite to the one surface 21a. The negative electrode active material layer 23 is not formed on the other surface 21b. In the laminated body 5, the other surface 20b of the first current collector 20 of one storage cell 2 and the other surface 21b of the second current collector 21 of another storage cell 2 face each other (here, they are in contact with each other). As described above), it is configured by stacking a plurality of storage cells 2.

As a result, in the laminated body 5, a plurality of storage cells 2 are electrically connected in series. In the laminated body 5, the storage cells 2 adjacent to each other in the stacking direction form a pseudo bipolar electrode 10 having the first current collector 20 and the second current collector 21 in contact with each other as electrode bodies. That is, one bipolar electrode 10 includes a first current collector 20, a second current collector 21, a positive electrode active material layer 22, and a negative electrode active material layer 23. A first current collector 20 (positive electrode 11) is arranged as a terminal electrode at one end in the stacking direction. A second current collector 21 (negative electrode 12) is arranged as a terminal electrode at the other end in the stacking direction. Here, the directions along the one surface 20a, 21a and the other surfaces 20b, 21b are the X-axis direction and the Y-axis direction.

Each of the first current collector 20 and the second current collector 21 (hereinafter, may be simply referred to as a “current collector”) has a positive electrode active material layer 22 and a negative electrode during discharging or charging of the lithium ion secondary battery. It is a chemically inert electric conductor for continuing to pass an electric current through the active material layer 23. As the material constituting the current collector, for example, a metal material, a conductive resin material, a conductive inorganic material, or the like can be used. Examples of the conductive resin material include a conductive polymer material and a resin obtained by adding a conductive filler to a non-conductive polymer material as needed. The current collector may include a plurality of layers including one or more layers including the above-mentioned metal material or conductive resin material. The surface of the current collector may be covered with a known protective layer. The surface of the current collector may be treated by a known method such as plating.

The current collector may have a form such as a foil, a sheet, a film, a wire, a rod, a mesh, or a clad material. The current collector may be, for example, a metal foil such as a nickel foil, a titanium foil, or a stainless steel foil, in addition to the aluminum foil and the copper foil. From the viewpoint of ensuring mechanical strength, the current collector may be a stainless steel foil (for example, SUS304, SUS316, SUS301, SUS304, etc. specified in JIS G 4305: 2015). The current collector may be an alloy foil of the above metal. The first current collector 20 may be a foil containing a base material coated with an aluminum film. In the present embodiment, the first current collector 20 is an aluminum foil and the second current collector 21 is a copper foil. The second current collector 21 may be a foil containing a base material coated with a copper film. In the case of a foil-shaped current collector, the thickness of the current collector may be in the range of 1 μm to 100 μm.

The positive electrode active material layer 22 contains a positive electrode active material that can occlude and release charge carriers such as lithium ions. As the positive electrode active material, a material that can be used as a positive electrode active material for a lithium ion secondary battery, such as a lithium composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, and a polyanionic compound, may be adopted. Further, two or more kinds of positive electrode active materials may be used in combination. In the present embodiment, the positive electrode active material layer 22 contains olivine-type lithium iron phosphate (LiFePO ₄ ) as a composite oxide.

The negative electrode active material layer 23 can be used without particular limitation as long as it is a simple substance, an alloy or a compound capable of occluding and releasing charge carriers such as lithium ions. For example, examples of the negative electrode active material include Li, carbon, metal compounds, elements that can be alloyed with lithium, or compounds thereof. Examples of carbon include natural graphite, artificial graphite, hard carbon (non-graphitizable carbon) and soft carbon (easy graphitizable carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon and tin. In the present embodiment, the negative electrode active material layer 23 contains graphite as a carbon-based material.

Each of the positive electrode active material layer 22 and the negative electrode active material layer 23 (hereinafter, may be simply referred to as “active material layer”) is a conductive auxiliary agent, a binder, and an electrolyte (hereinafter, may be simply referred to as “active material layer”) for increasing electrical conductivity, if necessary. It may further contain a polymer matrix, an ionic conductive polymer, an electrolytic solution, etc.), an electrolyte supporting salt (lithium salt) for enhancing ionic conductivity, and the like. The components contained in the active material layer, the compounding ratio of the components, and the thickness of the active material layer are not particularly limited, and conventionally known findings regarding a lithium ion secondary battery can be appropriately referred to. The thickness of the active material layer is, for example, 2 to 150 μm. In order to form the active material layer on the surface of the current collector, a conventionally known method such as a roll coating method may be used. In order to improve the thermal stability of the positive electrode 11 or the negative electrode 12, a heat-resistant layer may be provided on the surface (one side or both sides) of the current collector or the surface of the active material layer. The heat-resistant layer may contain, for example, inorganic particles and a binder, and may also contain an additive such as a thickener.

The conductive auxiliary agent is added to increase the conductivity of the positive electrode 11 or the negative electrode 12. Therefore, the conductive auxiliary agent may be arbitrarily added when the conductivity of the positive electrode 11 or the negative electrode 12 is insufficient, or may not be added when the conductivity of the positive electrode 11 or the negative electrode 12 is sufficiently excellent. good. The conductive auxiliary agent is, for example, acetylene black, carbon black, graphite or the like.

The binder serves to anchor the active material or the conductive auxiliary agent to the surface of the current collector. Examples of the binder include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamideimide, resins containing an alkoxysilyl group, and poly (poly). Meta) Acrylic resins such as acrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, sodium alginate, arginates such as ammonium alginate, water-soluble cellulose ester cross-linking products, starch-acrylic acid graft polymers can be exemplified. can. These binders can be used alone or in combination. As the solvent, for example, water, N-methyl-2-pyrrolidone (NMP) and the like are used.

The separator 13 separates the positive electrode 11 and the negative electrode 12 and allows a charge carrier such as lithium ion to pass through while preventing a short circuit due to contact between the two electrodes. The separator 13 is arranged between the positive electrode 11 and the negative electrode 12. The separator 13 prevents a short circuit between the adjacent bipolar electrodes 10 and 10 when the storage cell 2 is stacked.

The separator 13 is, for example, a porous sheet or a non-woven fabric containing a polymer that absorbs and retains an electrolyte. As the material constituting the separator 13, for example, a porous film made of polypropylene (PP) is used. The material constituting the separator 13 may be a woven fabric or a non-woven fabric made of polypropylene, methyl cellulose or the like. The separator 13 may have a single-layer structure or a multi-layer structure. The multilayer structure may have, for example, a ceramic layer as a heat-resistant layer. The separator 13 may be impregnated with an electrolyte. The separator 13 itself may be composed of an electrolyte such as an all-solid electrolyte (polymer solid electrolyte, inorganic solid type electrolyte).

As the electrolyte impregnated in the separator 13, specifically, as a conventionally known material, a liquid electrolyte (electrolyte solution) or a polymer gel electrolyte can be used. The electrolytic solution contains a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent. The polymer gel electrolyte contains an electrolyte retained in the polymer matrix.

The electrolytic solution contains a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent. As the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers can be used. In addition, these materials may be used alone or in combination of two or more. As the electrolyte, known lithium salts such as LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (FSO ₂ ) ₂ , and LiN (CF ₃ SO ₂ ) ₂ can be used.

The spacer 14 is formed between at least the first current collector 20 and the second current collector 21, and the spacer 14 is formed at least one of the first current collector 20 and the second current collector 21 (for example, the first current collector 20). And both, or only one of the first current collector 20 and the second current collector 21). The spacer 14 contains an insulating material and prevents a short circuit by insulating between the first current collector 20 and the second current collector 21. In this embodiment, the spacer 14 contains polyethylene (PE), which is a resin, as an insulating material. Examples of the resin material constituting the spacer 14 include polystyrene, ABS resin, modified polypropylene (modified PP), and acrylonitrile styrene (AS) resin, in addition to polyethylene (PE).

In the present embodiment, the spacer 14 extends along the edge portion 20e of the first current collector 20 or the edge portion 21e of the second current collector 21. The spacer 14 is a frame surrounding the positive electrode active material layer 22 or the negative electrode active material layer 23 when viewed from the stacking direction.

In the present embodiment, the spacer 14 also functions as a frame-shaped sealing portion for sealing the space S between the first current collector 20 and the second current collector 21. In the present embodiment, the spacer 14 arranged in each storage cell 2 has a portion arranged between the pair of current collectors and a portion extending outward from the edge portion of the current collectors, and has a stacking direction. The portions extending to the outside of the spacer 14 adjacent to the spacer 14 are joined and integrated. A plurality of spacers 14 are integrated to form a sealed body 14a. The space S surrounded by the spacer 14, the first current collector 20, and the second current collector 21 contains an electrolyte (electrolyte solution) impregnated in the separator 13. In the present embodiment, the spacer 14 has a rectangular frame shape in a plan view, and is welded to the edge portion 20e of the first current collector 20 and the edge portion 21e of the second current collector 21. The sealing body 14a extends in the stacking direction from the first current collector 20 arranged at one end of the laminated body 5 in the stacking direction to the second current collector 21 arranged at the other end in the stacking direction. The sealing body 14a is a tubular member.

The spacer 14 can prevent leakage of the electrolyte by sealing the space S between the positive electrode 11 and the negative electrode 12. Further, the spacer 14 can prevent moisture from entering the space S from the outside of the power storage device 1 by sealing the space S between the positive electrode 11 and the negative electrode 12. Further, the spacer 14 can prevent the gas generated from the positive electrode 11 or the negative electrode 12 from leaking to the outside of the power storage device 1 due to, for example, a charge / discharge reaction. The separator 13 is positioned by being sandwiched between the spacer 14 and the first current collector 20 at the edge portion 13e.
[Example of detection unit]

Subsequently, an example of the detection unit 50 shown in FIG. 1 will be described. FIG. 2 is an enlarged cross-sectional view showing a part of the power storage device shown in FIG. FIG. 3 is a front view (a view when viewed from the X direction) of the portion shown in FIG. As shown in FIGS. 1 to 3, in this example, the detection unit 50 is provided for each of the storage cells 2. Here, the detection unit 50 is used to detect the respective voltage of the storage cell 2 as the state of the storage cell 2. The detection unit 50 includes a voltage detection line (detection line) 51 and a connector unit 52A. The voltage detection line 51 is provided so as to reach the inside of the laminated body 5 from the outside of the laminated body 5 via the spacers 14 of the two adjacent storage cells 2.

More specifically, the voltage detection line 51 includes one end 51a and the other end 51b on the opposite side of the one end 51a. One end 51a of the voltage detection line 51 is arranged inside the laminated body 5, and the other end 51b is arranged outside the laminated body 5. The outside of the laminated body 5 is outside the outer edge 14e of the spacer 14 (opposite side of the space S) when viewed from the stacking direction. Therefore, the voltage detection line 51 includes a portion (a portion in contact with the spacer 14) that overlaps the spacer 14 when viewed from the stacking direction between the one end portion 51a and the other end portion 51b. For example, an insulating coating 53 may be provided on the portion overlapping the spacer 14.

One end 51a of the voltage detection line 51 is formed on the other side 20b (of the first current collector 20) of one of the storage cells 2 adjacent to each other and the (second current collector) of the other storage cell 2. It is interposed between the other surface 21b (of the body 21) and is in contact with the other surface 20b and the other surface 21b. As a result, the voltage detection line 51 is electrically connected to the first current collector 20 of one of the storage cells 2 adjacent to each other and the second current collector 21 of the other storage cell 2. There is. In particular, one end portion 51a reaches a region between the positive electrode active material layer 22 and the negative electrode active material layer 23 when viewed from the stacking direction.

In this way, the voltage detection line 51 is interposed between the other surface 20b and the other surface 21b facing each other, and is connected to the first current collector 20 and the second current collector 21. The connection portion (the portion in contact here) between the voltage detection line 51 and the first current collector 20 and the second current collector 21 is located inside the outer edge 14e of the spacer 14 when viewed from the stacking direction. ing. Further, the voltage detection line 51 extends so as to overlap the positive electrode active material layer 22 and the negative electrode active material layer 23 when viewed from the stacking direction. As a result, when a restraining pressure is applied to the laminated body 5 along the stacking direction, the first current collector 20, the voltage detection line 51, and the first current collector layer 20 pass through the positive electrode active material layer 22 and the negative electrode active material layer 23. Confining pressure can be effectively applied to the laminated structure of the two current collectors 21. The power storage device 1 may include a restraining member for applying a restraining pressure to the laminated body 5 along the stacking direction. The voltage detection line 51 may be thinner than each of the first current collector 20 and the second current collector 21.

The connector portion 52A is a resin member having an insulating property and is for holding the voltage detection line 51 and connecting to the outside. Here, the connector portions 52A are arranged in a row in the stacking direction (see FIG. 3). Here, connecting to the outside means connecting to an element other than the storage cell 2. Therefore, when the power storage device 1 includes a unit that receives an input of a state detection result such as the voltage of the power storage cell 2, the connector unit 52A connects the voltage detection line 51 to the unit (external) in the power storage device 1. It will be for connecting to. On the other hand, when the power storage device 1 does not include the control unit, the connector portion 52A is for connecting the voltage detection line 51 to a device (external) different from the power storage device 1. The same applies to the connector portion 52B described later.

The connector portion 52A is located outside the laminated body 5 (outside the outer edge 14e of the spacer 14). The connector portion 52A is provided with a recess 52P. The recess 52P is opened toward the side opposite to the laminated body 5 (here, in the Y direction). The voltage detection line 51 is held by the connector portion 52A at the other end portion 51b and is exposed on the inner surface 52s of the recess 52P. As a result, the connector portion 52A is configured as a female type connector, and by inserting another male type connector into the recess 52P, an electrical connection with the voltage detection line 51 is made in the connector portion 52A. It becomes. At least a part of the connector portion 52A may be located inside the outer edge 14e of the spacer 14. In this case, it is desirable to reduce the thickness of the spacer 14 in the stacking direction according to the thickness of the connector portion 52 in the stacking direction.

The power storage device 1 further includes a sealing portion (fixing portion) 60 that forms a sealing space together with the spacer 14 of the storage cells 2 adjacent to each other and the connector portion 52A. The sealing portion 60 may be made of, for example, the same material as the spacer 14 and / or the connector portion 52A. In this case, the sealing portion 60 can be configured as a welding portion generated by welding each spacer 14 and the connector portion 52A. As a result, the sealing portion 60 fixes the connector portion 52A to each spacer 14. However, the sealing portion 60 is configured by arranging another member made of the same material as the spacer 14 and / or the connector portion 52A between the spacer 14 and the connector portion 52A (for example, applying resin). May be good. Further, the sealing portion 60 may be made of a material different from that of the spacer 14 and / or the connector portion 52A. Even in these cases, the sealing portion 60 can fix the connector portion 52A to the spacer 14. In the power storage device 1, instead of the sealing portion 60, the spacer 14 and the connector portion 52A are welded or adhered to each other without forming a sealing space together with the spacer 14 and the connector portion 52A of the storage cell 2 adjacent to each other. A fixing portion for fixing may be provided. In this case, the fixed portion may not be welded or adhered to both of the spacers 14 of the storage cells 2 adjacent to each other, but may be welded or adhered to a single spacer 14.

In the present embodiment, the connection portion between the voltage detection line 51 and the first current collector 20 and the second collector 21 is a portion (held by the connector portion 52A and held by the connector portion 52A) exposed to the inner surface 52s of the connector portion 52A. Except for the enclosed portion), it is located in the space sealed by the sealing portion 60 inside the spacer 14 and the connector portion 52A, and is configured so that the portion exposed to the outside is reduced. The exposed portion of the voltage detection line 51 is not exposed to the outside by inserting another male connector when connecting to the outside.

In the illustrated example, the voltage detection line 51 has a constant thickness (thickness) from the one end portion 51a to the entire other end portion 51b. However, the thickness of the voltage detection line 51 is not limited to the case where it is constant from the one end portion 51a to the other end portion 51b, and may be changed. That is, at one end portion 51a sandwiched between the first current collector 20 and the second current collector 21, for example, the influence on the electrical connection between the first current collector 20 and the second current collector 21. It is conceivable to make the voltage detection line 51 thin (thin) so as to suppress the increase in the thickness of the laminated body 5 or to suppress the increase in the thickness of the laminated body 5.

On the other hand, at the other end portion 51b held by the connector portion 52A, it is conceivable that the voltage detection line 51 is thickly configured so as to withstand contact when inserting or removing another connector. From such a viewpoint, as an example, the voltage detection line 51 can be configured to be relatively thin at one end portion 51a and the voltage detection line 51 can be configured to be relatively thick at the other end portion 51b.
[Another example of detection unit]

Subsequently, another example of the detection unit 50 shown in FIG. 1 will be described. FIG. 4 is an enlarged cross-sectional view showing a part of the power storage device shown in FIG. As shown in FIGS. 1 and 4, the detection unit 50 of this example differs from the detection unit 50 shown in FIGS. 2 and 3 in that the connector unit 52B is provided instead of the connector unit 52A. It is in agreement in other respects. The connector portion 52B includes a conductive member 54 connected to the voltage detection line 51 and a holding portion 55 for holding the conductive member 54.

Here, the conductive member 54 is integrally formed with the voltage detection line 51 as an example. However, the conductive member 54 may be formed separately from the voltage detection line 51 and may be joined to each other. The holding portion 55 holds the conductive member 54 so as to surround the conductive member 54 over the entire circumference of the conductive member 54 when viewed from the direction away from the laminated body 5 (here, the X direction). That is, the holding portion 55 holds the voltage detection line 51 by holding the conductive member 54. Therefore, the conductive members 54 are separated from each other by the holding portion 55 to ensure insulation. The conductive member 54 projects from the holding portion 55 in a direction away from the laminated body 5.

As a result, the connector portion 52B is configured as a male type connector, and another female type connector is fitted to the protruding portion of the conductive member 54 so as to be electrically connected to the voltage detection line 51 via the conductive member 54. The connection will be made. In this example as well, the thickness of the voltage detection line 51 may be changed as in the example using the connector portion 52A. Further, the connection portion between the voltage detection line 51 and the first current collector 20 and the second current collector 21 is located in a space sealed by the spacer 14 and the sealing portion 60 inside the connector portion 52B. It is configured so that the part exposed to the outside is reduced.
[Action / Effect]

As described above, the power storage device 1 includes a detection unit 50 for detecting the state of the power storage cells 2 constituting the laminated body 5. The detection unit 50 includes a voltage detection line 51 interposed between the current collectors of the storage cells 2 adjacent to each other. The voltage detection line 51 is held by the connector portions 52A and 52B for external connection. Therefore, when detecting the state of the storage cell 2 by using the detection unit 50, it is not necessary to prepare current collectors having various shapes. That is, it is possible to standardize the parts across the plurality of storage cells 2. Further, in the power storage device 1, since the voltage detection line 51 is held by the connector portions 52A and 52B, the load applied to the connection portion between the voltage detection line 51 and the voltage detection line 51 and the current collector can be reduced. That is, stable state detection becomes possible. As described above, according to the power storage device 1, it is possible to stably detect the state while sharing the components across the plurality of power storage cells 2.

In the power storage device 1, since the voltage detection line 51 is interposed between the current collectors of the power storage cells 2 adjacent to each other, the voltage detection line is in the space S sealed by the spacer 14 of each power storage cell 2. There is no need to introduce 51. Therefore, the state can be detected without adversely affecting the sealing of the space S by the spacer 14. Further, in the power storage device 1, since the connector portions 52A and 52B are located outside the spacer 14, the space between the power storage cells 2 is expanded as compared with the case where the connector is interposed between the current collector and the spacer 14. As a result, the deterioration of battery performance is suppressed.

Further, the power storage device 1 includes a fixing portion (sealing portion 60) for fixing the connector portions 52A and 52B to the spacer 14. Therefore, since the connector portions 52A and 52B are fixed to the spacer 14, the load is more easily absorbed, and the load applied to the connection portion between the current collector and the voltage detection line 51 is further reduced. Further, this fixing portion seals between the spacer 14 and the connector portions 52A and 52B (the sealing portion 60). Therefore, it is possible to prevent moisture or the like from entering between the voltage detection line 51 between the spacer 14 and the connector portions 52A and 52B.

Further, in the power storage device 1, a recess 52P is formed in the connector portion 52A. The connector portion 52A holds the voltage detection line 51 so that the voltage detection line 51 is exposed on the inner surface 52s of the recess 52P. As a result, the connector portion 52A can be configured as a female type. Alternatively, in the power storage device 1, the connector portion 52B includes a conductive member 54 connected to the voltage detection line 51 and a holding portion 55 for holding the conductive member 54. The conductive member 54 protrudes from the holding portion 55. As a result, the connector portion 52B can be configured as a male type.

Further, in the power storage device 1, the voltage detection line 51 extends so as to overlap the positive electrode active material layer 22 and the negative electrode active material layer 23 when viewed from the stacking direction. A restraining pressure may be applied to the portion of the current collector in which the positive electrode active material layer 22 and the negative electrode active material layer 23 are formed in order to ensure battery performance. In this case, the confining pressure is also applied to the connection portion between the voltage detection line 51 and the current collector, so that the contact between the voltage detection line 51 and the current collector can be reliably maintained.

Further, the voltage detection line 51 is a sealing portion inside the spacer 14 and the connector portions 52A and 52B, except for a portion exposed on the inner surface 52s of the connector portion 52A (a portion held and surrounded by the connector portion 52A). It is located in the space sealed by 60, and is configured so that the portion exposed to the outside is reduced. Therefore, the exposure of the voltage detection line 51 to the outside is further reduced, and the increase in electrical resistance due to the load applied to the connection portion or the occurrence of corrosion is further suppressed.
[Modification example]

The above embodiments have described one aspect of the present invention. Therefore, the present invention is not limited to the above embodiment and can be arbitrarily modified.

FIG. 5 is a cross-sectional view showing a voltage detection line according to a modified example. FIG. 5A shows an example when the connector portion 52A is used, and FIG. 5B shows an example when the connector portion 52B is used. As shown in FIG. 5, the voltage detection wire 51 includes a conductor portion 56 and an insulating layer 57 that covers a part of the conductor portion 56. More specifically, the conductor portion 56 is exposed from the insulating layer 57 at one end 51a and the other end 51b of the voltage detection wire 51, and is exposed to the insulating layer 57 between the one end 51a and the other end 51b. It is covered.

Then, in the one end portion 51a of the voltage detection line 51, the voltage detection line 51 is electrically connected to the first current collector 20 and the second current collector 21 in the portion exposed from the insulating layer 57 of the conducting wire portion 56. (I'm in contact here). Further, in the other end portion 51b of the voltage detection line 51, a portion exposed from the insulating layer 57 of the conducting wire portion 56 is exposed on the inner surface 52s of the recess 52P (connector portion 52A). Further, in the other end portion 51b of the voltage detection wire 51, a portion exposed from the insulating layer 57 of the conducting wire portion 56 is joined to the conductive member 54 (connector portion 52B). The voltage detection line 51 having such an insulating layer 57 can be formed from FPC as an example. In this case, the electrical insulation is improved except for the connection portion between the current collector and the voltage detection line 51.

Since the voltage detection lines 51 are insulated from each other by the connector portions 52A and 52B outside the laminated body 5, the plurality of detection units 50 are located at the same position in the Y direction so as to overlap each other when viewed from the stacking direction. However, they may be arranged at different positions in the Y direction so that at least adjacent objects do not overlap each other when viewed from the stacking direction.

Further, the plurality of connector portions 52A may be integrally formed with each other, or may be formed separately from each other. When a plurality of connector portions 52A are formed separately from each other, the connector portions 52A adjacent to each other may be in contact with each other or may be separated from each other. The same applies to the connector portion 52B. Further, the detection unit 50 may be configured to detect another state such as temperature instead of the voltage of the storage cell 2. Further, the detection unit 50 may not be provided for all the storage cells 2, and the voltage detection line 51 is connected to one of the first current collector 20 and the second current collector 21. May be good.

Here, one of the positive electrode active material layer 22 and the negative electrode active material layer 23 can be formed larger than the other. In the above embodiment, as described above, the negative electrode active material layer 23 is formed larger than the positive electrode active material layer 22 when viewed from the stacking direction. Therefore, when viewed from the stacking direction, a region R1 that overlaps with the negative electrode active material layer 23 but does not overlap with the positive electrode active material layer 22 is generated. The voltage detection line 51 may be terminated in this region R1 while extending so as to reach this region R1 when viewed from the stacking direction. That is, in the power storage device 1, the voltage detection line 51 extends so as to overlap only the larger of the positive electrode active material layer 22 and the negative electrode active material layer 23 (here, the negative electrode active material layer 23) when viewed from the stacking direction. You may be doing it.

Further, in the power storage device 1, there may be a region R2 in the space S that is inside the spacer 14 and does not overlap the positive electrode active material layer 22 and the negative electrode active material layer 23 when viewed from the stacking direction. .. The region R2 corresponds to the portion of the unformed region of the active material layer in the current collector exposed from the spacer 14. In this case, the voltage detection line 51 may extend to this region R2 and be terminated in this region R2. That is, the voltage detection line 51 may extend in the space S so as not to overlap both the positive electrode active material layer 22 and the negative electrode active material layer 23 when viewed from the stacking direction. Further, the voltage detection line 51 may be terminated in a region R3 outside the inner edge of the spacer 14 and inside the outer edge of the current collector when viewed from the stacking direction.

1 ... power storage device (power storage module), 5 ... laminated body, 14 ... spacer, 14e ... outer edge, 20 ... first current collector, 20a ... one side (first surface), 20b ... other side (third surface), 21 ... 2nd current collector, 21a ... one surface (first surface), 21b ... other surface (fourth surface), 22 ... positive electrode active material layer (first active material layer), 23 ... negative electrode active material layer (first surface) 2 active material layer), 50 ... detection part, 51 ... voltage detection line (detection line), 52A, 52B ... connector part, 52P ... recess, 52s ... inner surface, 54 ... conductive member, 55 ... holding part, 56 ... conductor part , 57 ... Insulation layer, 60 ... Sealing part (fixing part).

Claims (10)

A laminated body containing a plurality of storage cells stacked on each other,
A detection unit for detecting the state of the storage cell and
Equipped with
The storage cell is
A first electrode including a first current collector and a first active material layer provided on the first surface of the first current collector, and a first electrode.
The second current collector and the second active material layer provided on the second surface of the second current collector and having a polarity different from that of the first active material layer are included, and the second active material layer is the first active material layer. A second electrode laminated on the first electrode so as to face the material layer, and
It is provided between the first current collector and the second current collector so as to surround the first active material layer and the second active material layer when viewed from the stacking direction of the first electrode and the second electrode. Spacer and
Including
The laminated body is opposite to the third surface of the first current collector of one storage cell opposite to the first surface and the second surface of the second current collector of another storage cell. It is configured by stacking the plurality of storage cells so as to face the fourth surface on the side.
The detection unit
A detection line interposed between the third surface and the fourth surface facing each other and connected to the first current collector and / or the second current collector.
A connector portion for holding the detection line and connecting the detection line to the outside,
Have,
Power storage module. A fixing portion for fixing the connector portion to the spacer is provided.
The power storage module according to claim 1. A sealing space is formed by the fixed portion, the spacer of the one storage cell, the spacer of the other storage cell, and the connector portion.
The detection line is arranged in the sealing space.
The power storage module according to claim 2. The connector portion is located outside the outer edge of the spacer when viewed from the stacking direction.
The power storage module according to any one of claims 1 to 3. The detection line is a voltage detection line electrically connected to the first current collector and / or the second current collector.
The power storage module according to any one of claims 1 to 4. The detection wire includes a conducting wire portion and an insulating layer covering a part of the conducting wire portion, and the first current collector and / or the second current collector in the portion of the conducting wire portion exposed from the insulating layer. Electrically connected to the body,
The power storage module according to any one of claims 1 to 5. A recess is formed in the connector portion, and the connector portion has a recess.
The connector portion holds the detection line so that the detection line is exposed on the inner surface of the recess.
The power storage module according to any one of claims 1 to 6. The connector portion includes a conductive member connected to the detection line and a holding portion for holding the conductive member.
The conductive member protrudes from the holding portion.
The power storage module according to any one of claims 1 to 6. The detection line extends so as to overlap the first active material layer and the second active material layer when viewed from the stacking direction.
The power storage module according to any one of claims 1 to 8. The second active material layer is formed larger than the first active material layer when viewed from the stacking direction.
The detection line extends so as to overlap only the second active material layer of the first active material layer and the second active material layer when viewed from the stacking direction.
The power storage module according to any one of claims 1 to 8.

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