BATTERY MODULE

To provide a battery module capable of improving the workability in manufacturing. A battery module (1) includes: a plurality of battery cells (10) each including: a battery (11); and an exterior packaging body (12) that houses the battery (11). The battery (11) incudes: a negative electrode including a negative electrode current collector; an electrolyte; and a positive electrode including a positive electrode current collector. The plurality of battery cells (10) each include: a current collector tab (13, 15) extending from each of the positive electrode current collector and the negative electrode current collector; and a current collector tab lead (14, 16) connected to each of the current collector tabs (13, 15). The current collector tab lead (14, 16) extends in a vertical direction (y2) perpendicular to the stacking direction (y1) of the plurality of battery cells (10).

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2020-104381, filed on 17 Jun. 2020, the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a battery module.

Related Art

Recently, the demand for battery devices with high capacity and high output has rapidly expanded due to the spread of various electric and electronic devices of various sizes, such as automobiles, personal computers, and mobile phones.

Examples of such battery devices include a liquid battery cell that includes an organic electrolytic solution as an electrolyte between a positive electrode and a negative electrode, and a solid-state battery cell that includes a solid electrolyte instead of an electrolyte of an organic electrolytic solution.

There is known a laminated cell type in which such a battery is wrapped in a laminated film (exterior packaging body) and sealed in a plate shape.

In applications such as electric vehicles arid hybrid electric vehicles, a battery module in which a plurality of such laminated cell type battery cells are disposed and housed in a case is used. Wrapping the battery in an exterior packaging body prevents atmospheric gas from entering the battery (for example, see Patent Document 1).

Patent Document 1: PCT International Publication No. WO2019/188825

SUMMARY OF THE INVENTION

Since the battery cell in the battery module disclosed in Patent Document 1 includes an exterior packaging body in which one film is folded back, dead space can be reduced, and the volume energy density of the battery module can be improved.

On the other hand, the bus bar is disposed in a direction in which the current collector tab lead extends, i.e., on the side face side of the battery module, and thus workability is poor when welding the bus bar and the current collector tab lead.

In response to the above issue, it is an object of the present invention to provide a battery module capable of improving the workability in manufacturing.

A first aspect of the present invention relates to a battery module, including: a plurality of battery cells each including: a battery; and an exterior packaging body that houses the battery. The battery includes: a negative electrode including a negative electrode current collector; an electrolyte; and a positive electrode including a positive electrode current collector. The plurality of battery cells each include: a current collector tab extending from each of the positive electrode current collector and the negative electrode current collector; and a current collector tab lead connected to each of the current collector tabs. The current collector tab lead extends in a vertical direction perpendicular to a stacking direction of the plurality of battery cells.

According to the first aspect, it is possible to provide a battery module capable of improving the workability in manufacturing.

In a second aspect of the present invention according to the first aspect, the battery module further includes a connecting portion that connects the current collector tab leads to one another. At least one of the current collector tab leads extends vertically upward perpendicular to the stacking direction and is connected by the connecting portion.

According to the second aspect, it is possible to more preferably improve the workability in manufacturing the battery module.

In a third aspect of the present invention according to the second aspect, the connecting portion connects the current collector tab leads adjacent to one another. The adjacent current collector tab leads that extend vertically upward perpendicular to the stacking direction and are connected to one another by the connecting portion, and the adjacent current collector tab leads that extend vertically downward perpendicular to the stacking direction and are connected to one another by the connecting portion, are provided alternately in the stacking direction.

According to the third aspect, the plurality of battery cells can be uniformly connected by the connecting portions, stacking misalignment of the plurality of battery cells can be preferably suppressed, and damage to the electrode plate can be prevented.

In a fourth aspect of the present invention according to any one of the first aspect to the third aspect, at least one of the current collector tab leads is used by bending its leading end that extends in the vertical direction.

According to the fourth aspect, the current collector tab leads can be easily connected to one another by welding or the like, and thus it is possible to more preferably improve the workability in manufacturing the battery module.

In a fifth aspect of the present invention according to any one of the first aspect to the fourth aspect, the battery cell is a solid-state battery cell.

According to the fifth aspect, it is possible to constitute a battery module while suppressing stacking misalignment of the solid-state batteries and cracking of the electrode plates.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiments exemplify the present invention, and the present invention is not limited to the following embodiments.

First Embodiment

As shown inFIG. 1, a battery module1according to a first embodiment includes a plurality of battery cells10, a support2, a cooling plate3, a mounting plate A, a vibration insulating material5, and a fixing film6.

The battery module1is constituted by the plurality of battery cells10stacked on and electrically connected to one another.

The plurality of battery cells10are stacked and disposed in the stacking direction indicated by an arrow y1inFIG. 1.

From the plurality of battery cells10, negative electrode current collector tab leads14and positive electrode current collector tab leads16constituting the electrodes extend outward.
The extension direction is vertically upward in a vertical direction perpendicular to the above stacking direction.
The vertical direction is indicated by an arrow y2inFIG. 1.
The current collector tab leads adjacent to one another are electrically connected to one another by a bus bar20as a connecting portion.
Thus, the connecting portion can be disposed at the top of the battery module1, and thus it is possible to improve the workability in manufacturing the battery module1.
Further, when connecting the plurality of battery cells10, it is possible to suppress stacking misalignment.

The plurality of battery cells10are connected in series, for example.

As shown inFIG. 1, the plurality of battery cells10are stacked on one another such that adjacent current collector tab leads are of different types.
The adjacent negative electrode current collector tab lead14and positive electrode current collector tab lead16of one of adjacent battery cells10are connected by the bus bar20as a connecting portion.
The connection method of the plurality of battery cells10is not limited to the above.
The plurality of battery cells10may be connected in parallel, for example.
In this case, the plurality of battery cells10are stacked so that current collector tab leads of the same type are disposed on the same end face of the battery module1.
The current collector tab leads of the same type are electrically connected to one another.

The negative electrode current collector tab lead14and the positive electrode current collector tab lead16each may extend vertically upward and have its leading end bent so as to be substantially horizontal to the stacking direction.

Thus, the constitution of the bus bar20can be simplified, and also the current collector tab leads can be easily connected to the bus bar20more easily by welding or the like.

Next, components constituting the battery module1according to the present embodiment will be described.

As shown inFIG. 2, the battery cell10includes a battery11, an exterior packaging body12, a negative electrode current collector tab13, a positive electrode current collector tab15, the negative electrode current collector tab lead13, and the positive electrode current collector tab lead16.

In this specification, the “battery” does not include an exterior packaging body, and has a structure in which the above-described current collector tab leads are connected to a laminate described below.
The “battery cell” includes a “battery” and an exterior packaging body.

The battery11includes a laminate including a negative electrode including a negative electrode current collector, an electrolyte, and a positive electrode including a positive electrode current collector. The battery11may be a liquid battery using an organic electrolytic solution as an electrolyte, a battery including a gel electrolyte, or a solid-state battery including a flame-retardant solid electrolyte as an electrolyte.

Since the battery module1according to the present embodiment can suppress stacking misalignment, it is preferable that the battery11is a solid-state battery, which is highly susceptible to stacking misalignment.
If the battery11is a solid-state battery, to obtain a preferable input-output characteristics, it is necessary to bind the plurality of battery cells10by applying high pressure. If the stacking misalignment of the solid-state batteries occurs, uniform pressure cannot be applied to the laminates.
Therefore, when stacking misalignment occurs, the input-output characteristics and the durability are deteriorated.
In the battery module1according to the present embodiment, since stacking misalignment can be suppressed when the battery11is a solid-state battery, preferable input-output characteristics as well as high durability can be obtained.
In the following description, the battery11will be described as a solid-state battery.

The negative electrode includes a negative electrode current collector and a negative electrode layer formed on one surface or both surfaces of the negative electrode current collector.

The positive electrode includes a positive electrode current collector and a positive electrode layer formed on one surface or both surfaces of the positive electrode current collector.

The negative electrode current collector is not particularly limited as long as it has a function of collecting current in the negative electrode layer.

Examples of the material of the negative electrode current collector include nickel, copper, and stainless steel.
Examples of the form of the negative electrode current collector include foil, plate, mesh, and foam, and foil is preferable among than,

The negative electrode layer contains at least a negative electrode active material.

As the negative electrode active material, a material capable of occluding and releasing ions (e.g., lithium ions) can be appropriately selected and used.
Specific examples of the negative electrode active material include lithium transition metal oxides such as lithium titanate (Li4Ti5O12), transition metal oxides such as TiO2, Nb2O3, and WO3, metal sulfides, metal nitrides, carbon materials such as graphite, soft carbon, and hard carbon, metallic lithium, metallic indium, and lithium alloys. The negative electrode active material may be in powder form or in a thin film form.

The positive electrode current collector is not particularly limited as long as it has a function of collecting current in the positive electrode layer.

Examples of the material of the positive electrode current collector include aluminum, an aluminum alloy, stainless steel, nickel, iron, and titanium.
Among them, aluminum, an aluminum alloy, and stainless steel are preferable.
Examples of the form of the positive electrode current collector include foil, plate, mesh, and foam.
Among them, foil is preferable.

The positive electrode layer contains at least a positive electrode active material.

As the positive electrode active material, a material capable of releasing and occluding ions (e.g., lithium ions) can be appropriately selected and used.
Specific examples of the positive electrode active material include lithium cobaltate (LiCoO2), lithium nickelate (LiNiO2), LiNipMnqCorO2(p+q+r=1), LiNipAlqCorO2(p+q+r=1), lithium manganate (LiMn2O4), heterogenous element-substituted Li—Mn spinel represented by Li1−i−xMn2−x−yMyO4(x+y=2, M is at least one selected from Al, Mg, Co, Fe, Mi, and Zn), and lithium metal phosphate (LiMPO4, M is at least one selected from Fe, Mn, Co, and Ni).

The electrolyte is disposed between the positive electrode and the negative electrode and contains at least an electrolyte material. The electrolyte is, for example, a solid electrolyte layer formed in the form of a film.

Ionic conduction (e.g., lithium ion conduction) can be performed between the positive electrode active material and the negative electrode active material via the solid electrolyte material contained in the solid electrolyte layer.

The exterior packaging body12houses the battery11.

The battery11is hermetically housed by the exterior packaging body12, which can prevent atmospheric gas from entering the battery11.

The exterior packaging body12consists of one film that is folded back at a side face of the battery11and joined so as to house the battery11having a substantially rectangular parallelepiped shape.

It is preferable that both ends of the film are each joined to themselves thus sandwiching the negative electrode current collector tab lead14and the positive electrode current collector tab lead16. Thus, the space of the joints in the exterior packaging body12, in which parts of the film are joined together, is reduced to suppress the formation of dead space, and the volume energy density of the battery module1can be effectively improved.
Alternatively, the exterior packaging body12may consist of two films, and may be sealed with four joints, joining the respective four edges of the two films facing each other.

The exterior packaging body12is formed of a film. The film is not particularly limited as long as it is a film capable of forming the exterior packaging body12that houses the battery11.

It is preferable that the film that forms the exterior packaging body12can provide airtightness to the exterior packaging body12.
The one film that forms the exterior packaging body12may be a single layer film or a laminate including a plurality of layers.

It is preferable that the film that forms the exterior packaging body12includes a barrier layer including an inorganic thin film such as aluminum foil, an inorganic oxide thin film such as silicon oxide or aluminum oxide, or the like, for example.

By providing the exterior packaging body12with the barrier layer, airtightness can be provided to the exterior packaging body12.

It is preferable that the film that forms the exterior packaging body12includes a seal layer including a thermoplastic resin such as polyethylene resin.

The seal layers laminated on the films face each other and are welded to each other, whereby the films can be joined together.
Therefore, the step of applying an adhesive is unnecessary.
The film that forms the exterior packaging body12may not include a seal layer.
It is also possible to form the exterior packaging body12by bonding the films together with an adhesive.

An example of the film that forms the exterior packaging body12is a laminate in which a base material layer made of polyethylene terephthalate, polyethylene naphthalate, nylon, polypropylene, or the like, a barrier layer as described above, and a seal layer as described above are laminated.

These layers may be laminated via a conventionally known adhesive, or may be laminated by an extrusion coating method or the like.

The preferable thickness of the film that forms the exterior packaging body12varies depending on the material used for the film, but the thickness is preferably 50 μm or more, and more preferably 100 μm or more.

The thickness of the film that forms the exterior packaging body12is preferably 700 μm or less, and more preferably 200 μm or less.

The negative electrode current collector tab13and the positive electrode current collector tab15are configured to respectively extend from the negative electrode current collector and the positive electrode current collector respectively provided on one end face and the other end face of the battery11.

In the present embodiment, the current collector tabs may extend from the respective current collectors.
That is, the current collector tabs may be formed by extending the respective current collectors, or may be a member different from the current collector.
The materials that can be used for the negative electrode current collector tab13and the positive electrode current collector tab15are not particularly limited, and the same materials as those conventionally used for solid-state batteries can be used.

It is preferable that the negative electrode current collector tab13and the positive electrode current collector tab15each are housed in a space formed between the portion in which the battery11is housed and the portion in which each current collector tab lead is housed in the exterior packaging body12.

The space is, for example, a triangular prismatic space composed of the faces continuous with the faces joined together by sandwiching each of the negative electrode current collector tab lead14and the positive electrode current collector tab lead16, and continuous with the upper and lower faces of the battery11.
The placement of the negative electrode current collector tab13and the positive electrode current collector tab15in this space enables the battery10to be less susceptible to external forces and improves the durability of the battery10.

As shown inFIG. 2, one part of each of the negative electrode-current collector tab lead14and the positive electrode current collector tab lead16is electrically connected inside the exterior packaging body12to each of the negative electrode current collector tab13and the positive electrode current collector tab15, respectively, by welding or the like.

Another part of the tab lead is exposed from the exterior packaging body12, to constitute an electrode portion of the battery cell10. The material of the current collector tab lead is not particularly limited, and is preferably a flexible linear plate member such as aluminum (Al) or copper (Cu).
The shape of the part exposed from the exterior packaging body12, of the current collector tab lead is not particularly limited, and may be a rectangular shape as shown inFIG. 2, another polygonal shape, a shape having a curved part, or the like.

The negative electrode current collector tab lead14and the positive electrode current collector tab lead16each extend in a direction different from a direction in which the connected current collector tab extends from the battery11, and are exposed from the exterior packaging body12.

As shown inFIG. 2, in the present embodiment, the negative electrode current collector tab lead14and the positive electrode current collector tab lead16each extend in a direction substantially perpendicular to a direction in which the connected negative electrode current collector tab13or positive electrode current collector tab15extends from the battery11.
In the present embodiment, the negative electrode current collector tab lead14and the positive electrode current collector tab lead16extend in the same direction.

The support2is a plate member that supports the battery cell10and prevents the battery cell10from being damaged.

The support2is sandwiched between adjacent battery cells10.
The support2is in contact with the exterior packaging body12of the battery cell10to support, a face of the battery cell10, thereby preventing the battery cell10from being damaged.
The support2may be configured to support the current collector tab or the current collector tab lead.
The material of the support2is not particularly limited, and a metal, a resin, or the like can be used.
As the support2, a metal having a high thermal conductivity is preferably used.
Thus, heat generated from the battery cell10can be efficiently dissipated.

The cooling plate3dissipates heat generated from the battery cell10by way of contact between the cooling plate3and the battery cell10.

In the present embodiment, the cooling plates3are disposed at both ends of the stacked battery cells10.
In addition to the above, the cooling plate3may be disposed on the mounting face of the battery cell10, between adjacent battery cells10, or the like.
The material of the cooling plate3is not particularly limited, and is preferably a material having high thermal conductivity such as metal.

The plurality of battery cells10are mounted on the mounting plate4.

The material, of the mounting plate4is not particularly limited, and is preferably a material having high thermal conductivity such as metal.
Thus, it is possible to effectively prevent the battery cell10from being damaged, and to effectively dissipate heat generated from the battery cell10.

The vibration insulating material5is disposed on the upper face of the mounting plate4.

The plurality of battery cells10are mounted on the upper face of the mounting plate4via the vibration insulating material5.
Mounting the plurality of battery cells10via the vibration insulating material5can effectively suppress vibration of the battery cells10.
As the material of the vibration insulating material5, a conventionally known material as a vibration insulating material, such as urethane rubber or silicone rubber, is used.

The fixing film6fixes the plurality of battery cells10. The fixing film6can effectively prevent the battery cells10from being damaged.

The material of the fixing film6is not particularly limited, and examples thereof include a paper, a cloth, a film (cellophane, OPP, acetate, polyimide, PVC, or the like), and an adhesive tape composed of a metal foil or the like.

Second Embodiment

A battery module1aaccording to a second embodiment of the present invention will be described below.

In the following description, description of portions common to those of the first embodiment may be omitted.
As shown inFIG. 3, the battery module1aincludes a plurality of battery cells10a.

The plurality of battery cells10aare stacked and disposed in the stacking direction indicated by an arrow y1inFIG. 3.

In the present embodiment, bus bars20aeach as connecting portions that connect a negative electrode current collector tab lead14aand a positive electrode current collector tab lead16aadjacent to one another are provided alternately in the stacking direction.
That is, pairs of adjacent negative electrode current collector tab lead14aand positive electrode current collector tab lead16athat extend vertically upward in the vertical direction indicated by an arrow y2inFIG. 3and are connected by the bus bars20a,and pairs of the adjacent current collector, tab leads that extend vertically downward and are connected similarly, are alternately provided in the stacking direction y1.
Thus, in the battery module1a,it is possible to equalise the pressure applied to the plurality of battery cells10awhen the plurality of battery cells10aare connected by the bus bar20aand fixed.
Therefore, the stacking misalignment of the battery cells10acan be preferably suppressed.

As shown inFIG. 4, the battery cell10aincludes the negative electrode current collector tab lead14aconnected to the negative electrode current collector tab13and the positive electrode current collector tab lead16aconnected to the positive electrode current collector tab15.

As shown inFIG. 4, the negative electrode current collector tab lead14aand the positive electrode current collector tab lead16aeach extend in a direction substantially perpendicular to a direction in which the connected current collector tab extends from the battery11.

The extending directions of the negative electrode current collector tab lead14aand the positive electrode current collector tab lead16aare opposite to each other.
In the battery module1aformed by stacking the battery cells10ahaving the above structure, the bus bars20aas connecting portions can be provided alternately in the stacking direction.

Although the preferable embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and any suitable modifications within a range that does not hinder the effect of the present invention are also included in the scope of the present invention.

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