WO2019077922A1

WO2019077922A1 - Secondary battery module

Info

Publication number: WO2019077922A1
Application number: PCT/JP2018/034291
Authority: WO
Inventors: 藤本　貴行
Original assignee: 株式会社日立製作所
Priority date: 2017-10-16
Filing date: 2018-09-14
Publication date: 2019-04-25
Also published as: JP2019075256A

Abstract

Provided is a secondary battery module that has a plurality of secondary battery cells, wherein: the secondary battery cells are composed by stacking electrode bodies that each have a positive electrode, a separator, and a negative electrode; the secondary battery cells have buffer materials inside the secondary battery cells and at ends in the in-surface direction of the electrode bodies; and the secondary battery module has end plates that hold the plurality of secondary battery cells therebetween in the direction of stacking the electrode bodies, side plates that hold the plurality of secondary battery cells therebetween in the in-surface direction of the electrode bodies, and top plate ribs that hold the plurality of secondary battery cells therebetween in a direction in which the end plates and the side plates are not disposed.

Description

Secondary battery module

The present invention relates to a secondary battery module.

The following content is disclosed by patent document 1 as a technique regarding a secondary battery module. The battery cell comprises: a plurality of battery cells; a case frame open at one end to accommodate the battery cells; and a finishing plate assembled to the open one end of the case frame, the case frame having an arrangement direction of the battery cells And a pair of side plates extending to cover both sides of the battery cell, and an end plate forming the other end closed between the pair of side plates, and the pair of side plates and end plates Is an integrally formed battery pack. As a result, in the process of assembling and modularizing two or more battery cells, a battery pack with an improved bonding structure is provided so as to achieve sufficient bonding strength while easily performing the assembly process.

JP, 2015-046379, A

In Patent Document 1, a battery cell is sandwiched between plates. The surface pressure from the plate may deform the battery cell. The deformation of the battery cell reduces the contact area between the battery cell and the plate, making it difficult to secure a heat radiation path from the battery cell to the plate and the outside. In Patent Document 1, there is no mention of the contact area between the battery cell and the plate due to deformation of the battery cell due to the surface pressure from the plate, and in the configuration of Patent Document 1, it is difficult to improve the heat dissipation of the secondary battery module .

An object of the present invention is to improve the heat dissipation of a secondary battery module.

The features of the present invention for solving the above problems are, for example, as follows.

It is a secondary battery module having a plurality of secondary battery cells, and the secondary battery cell is configured by laminating an electrode body having a positive electrode, a separator, and a negative electrode, and the secondary battery cell is formed in the secondary battery cell and A buffer material is provided at the end in the in-plane direction of the electrode body, and the end plate sandwiching the plurality of secondary battery cells in the stacking direction of the electrode body and the side sandwiching the plurality of secondary battery cells in the in-plane direction of the electrode body A secondary battery module comprising: a plate; and top plate ribs sandwiching a plurality of secondary battery cells in a direction in which end plates and side plates are not disposed.

According to the present invention, the heat dissipation of the secondary battery module can be improved. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

External view of secondary battery module Exploded view of secondary battery module Partially enlarged view of the secondary battery module Partially enlarged view of the secondary battery module External view of secondary battery cell Exploded view of secondary battery cell External view of secondary battery cell External view of secondary battery cell

Hereinafter, embodiments of the present invention will be described using the drawings and the like. The following description shows specific examples of the content of the present invention, and the present invention is not limited to these descriptions, and various modifications by those skilled in the art can be made within the scope of the technical idea disclosed herein. Changes and modifications are possible. Moreover, in all the drawings for explaining the present invention, what has the same function may attach the same numerals, and may omit explanation of the repetition.

As used herein, “to” is used in the sense of including the numerical values described before and after it as the lower limit value and the upper limit value. In the numerical range described step by step in the specification, the upper limit or the lower limit described in one numerical range may be replaced with the upper limit or the lower limit described in another step. The upper limit value or the lower limit value of the numerical range described in this specification may be replaced with the value shown in the examples.

In the present specification, a lithium ion secondary battery will be described as an example of a secondary battery cell. A lithium ion secondary battery is an electrochemical device capable of storing or utilizing electrical energy by insertion and extraction of lithium ions to an electrode in an electrolyte. This is called by another name of a lithium ion battery, a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery, and any battery is an object of the present invention. The technical concept of the present invention is also applicable to sodium ion secondary batteries, magnesium ion secondary batteries, calcium ion secondary batteries, zinc secondary batteries, aluminum ion secondary batteries and the like.

FIG. 1 is an external view of a secondary battery module. FIG. 2 is an exploded view of a secondary battery module. The secondary battery module 2000 includes a plurality of secondary battery cells 1000, a plurality of cell bus bars 600, two end plates 2100, two side plates 2200, a circuit board 2300, a first module bus bar 2400, a second module bus bar 2450, and a top plate It has 2500. The direction in which the end plate 2100 is disposed with respect to the plurality of secondary battery cells 1000 is the x-axis direction, the direction in which the side plate 2200 is disposed with respect to the plurality of secondary battery cells 1000 is the y-axis direction, xy plane The perpendicular direction of is the z-axis direction.

The end plate 2100 applies a surface pressure to the plurality of secondary battery cells 1000 in the x-axis direction (the stacking direction of the electrode assembly 400). The end plate 2100 is disposed on the surface on which the cell bar 600 is not disposed. The plurality of secondary battery cells 1000 are secured by the end plate 2100. It is desirable that the end plate 2100 be larger than the plurality of secondary battery cells 1000 in the yz plane and be formed over the entire surface of the secondary battery cell 1000 so that the plurality of secondary battery cells 1000 can be securely bound.

In the end plate 2100, a space through which the first module bus bar 2400 can pass is formed. In FIG. 2, an end plate opening 2110 is formed in the end plate 2100. In the yz plane, the end plate opening 2110 is larger than the first module bus bar 2400, and the end plate opening 2110 is sized to allow the first module bus bar 2400 to penetrate the end plate 2100. The end plate 2100 is made of a material such as steel, such as stainless steel, iron, or aluminum.

Side plate 2200 applies surface pressure to the plurality of secondary battery cells 1000 in the y-axis direction (in-plane direction of electrode assembly 400). Side plate 2200 is disposed on the surface on which cell bus bar 600 is disposed. The plurality of secondary battery cells 1000 are fixed by side plates 2200. By screwing the side plate 2200 onto the two end plates 2100, the two end plates 2100 are held by the side plate 2200. Since the direction of screwing between the side plate 2200 and the end plate 2100 is the same as the direction of fastening of the plurality of secondary battery cells 1000 by the end plate 2100, the rigidity of the secondary battery module 2000 can be enhanced. In addition, since the thickness of the side plate 2200 and the thickness of the end plate 2100 can be made substantially the same, the rigidity of the secondary battery module 2000 can be enhanced. The side plate 2200 is made of a steel material such as stainless steel, a material such as iron or aluminum.

The top plate 2500 applies a surface pressure to the plurality of secondary battery cells 1000 in the z-axis direction (the direction in which the end plate 2100 and the side plate 2200 are not disposed). The top plate 2500 is disposed on the surface on which the cell bar 600 is not disposed. The plurality of secondary battery cells 1000 are secured by the end plate 2100. The plurality of secondary battery cells 1000 are secured by the top plate 2500. The top plate 2500 is disposed on the top surface of the plurality of secondary battery cells 1000 in the z-axis direction. The top plate 2500 has top plate ribs 2510. The top plate rib 2510 can improve the bending rigidity of the top plate 2500.

Circuit board 2300 is formed between side plate 2200 and secondary battery cell 1000 in the y-axis direction. On the circuit board 2300, a converter device, an inverter device, a resistor, and the like are arranged. By forming circuit board 2300 between side plate 2200 and secondary battery cell 1000 in the y-axis direction, secondary battery module 2000 can be made compact.

Circuit board recesses 2310 are formed at both ends of the circuit board 2300 in the x-axis direction. The circuit board recess 2310 prevents interference between the first module bus bar 2400 and the circuit board 2300. Although the circuit board recess 2310 is formed at both ends of the circuit board 2300 in FIG. 2, the circuit board recess 2310 may be formed only at one end of the circuit board 2300.

FIG. 3 is a partially enlarged view of the secondary battery module. In order to electrically connect the adjacent secondary battery cells 1000 in series, a cell bus bar 600 is formed on the y-axis direction side of the secondary battery cells 1000. A first module bus bar 2400 and a second module bus bar 2450 are formed at both ends of the secondary battery module 2000 in the x-axis direction.

The first module bus bar 2400 protrudes from the end plate 2100 in the x-axis direction, and the second module bus bar 2450 is formed in the end plate 2100 in the x-axis direction. In the adjacent secondary battery modules 2000, by connecting one first module bus bar 2400 and the other second module bus bar 2450, the adjacent secondary battery modules 2000 are electrically connected in series. The cell bus bar 600, the first module bus bar 2400, and the second module bus bar 2450 are formed in the same plane. Thereby, the useless space in the secondary battery module 2000 is reduced, and the energy density of the secondary battery module 2000 can be improved. As a material of the first module bus bar 2400 and the second module bus bar 2450, a material having a relatively high electric conductivity such as copper or aluminum can be applied.

The first module bus bar 2400 protrudes relative to the cell bus bar 600 in the y-axis direction. The first module bus bar 2400 may be formed flush with the cell bus bar 600 in the y-axis direction. In that case, the second module bus bar 2450 may be eliminated, and the first module bus bar 2400 may be connected to the cell bus bar 600 to electrically connect the adjacent secondary battery modules 2000 in series. In this case, the cell bus bar 600 formed at the end in the x-axis direction becomes the second module bus bar 2450.

The secondary battery cell 1000 has an electrode terminal. The electrode terminals in the secondary battery cell 1000 are formed on both ends of the secondary battery cell 1000 in the z-axis direction, and the cell bus bars 600 are also formed on both ends of the secondary battery cell 1000 in the z-axis direction. It is done. The first module bus bar 2400 is formed between the cell bus bars 600 between screws for screwing the side plate 2200 and the end plate 2100 in the z-axis. The second module bus bar 2450 is formed on the top of the cell bus bar 600 in the z-axis. The cell bus bar 600 may be arranged to be biased in one direction in the z-axis direction. By forming the first module bus bar 2400 between the cell bus bars 600 in the z-axis direction, the reliability of the secondary battery module 2000 can be improved.

The cell bus bar 600 is electrically connected to the electrode terminal. The cell bus bar 600 electrically connects the plurality of secondary battery cells 1000. As a material of the cell bus bar 600, aluminum, an aluminum alloy, copper, a copper alloy or the like can be applied.

FIG. 4 is a partial enlarged view of a secondary battery module. FIG. 4 is a view of the secondary battery module 2000 as viewed from the x-axis direction. Side plate 2200 and end plate 2100 are fastened by end plate screw 2120. The top plate 2500, the end plate 2100, and the chassis 3000 of the vehicle body are fastened by the top plate screw 2520. Thus, the secondary battery module 2000 can be fixed to the vehicle body. A secondary battery pack case accommodating the secondary battery module 2000 may be used instead of the chassis 3000.

The secondary battery cell 1000 has an electrode assembly 400 and an outer package 500. When the material of the exterior body 500 of the secondary battery cell 1000 is a soft material such as polyolefin, when the surface pressure is applied to the secondary battery cell 1000 by the end plate screw 2120 or the side plate 2200 etc, the secondary battery cell 1000 As a result, the contact area between the secondary battery cell 1000 and the chassis 3000 is reduced, and it becomes difficult to secure a heat radiation path from the secondary battery cell 1000 to the chassis 3000 or the outside.

In FIG. 4, a buffer material 700 is formed in the secondary battery cell 1000 and between the electrode assembly 400 and the chassis 3000 (in-plane direction end of the electrode assembly 400). When securing the secondary battery cell 1000 in the z-axis direction by forming the buffer material 700, the buffer material 700 is deformed to relieve an excessive load on the electrode assembly 400 and prevent damage to the electrode assembly 400. be able to. Further, the heat generated in the electrode body 400 is easily transferred to the chassis 3000 side through the buffer material 700, and the heat dissipation of the secondary battery cell 1000 is improved. As a material of the shock absorbing material 700, for example, silicon gel can be applied.

FIG. 5 is an external view of a secondary battery cell. FIG. 6 is an exploded view of a secondary battery cell. 7 and 8 are external views of the secondary battery cell. The secondary battery cell 1000 includes a positive electrode 100 (electrode), a negative electrode 200 (electrode), a positive electrode terminal 150 (electrode terminal), a negative electrode terminal 250 (electrode terminal), a separator 300, an exterior body 500, and a buffer 700. As shown in FIG. 6, the direction in which the positive electrode 100, the negative electrode 200, and the separator 300 are stacked is the x-axis direction, the direction in which the electrode terminals are formed is the y-axis direction, and the perpendicular direction of the xy plane is the z-axis direction. .

The positive electrode 100 includes a positive electrode mixture layer 110 (electrode mixture layer), a positive electrode current collector 120, and a positive electrode tab 130 (electrode tab). The positive electrode mixture layer 110 is formed on both sides of the positive electrode current collector 120 (electrode current collector). A negative electrode 200, a negative electrode mixture layer 210 (electrode mixture layer), a negative electrode current collector 220 (electrode current collector), and a negative electrode tab 230 (electrode tab) are provided. A negative electrode mixture layer 210 is formed on both sides of the negative electrode current collector 220.

The positive electrode 100, the separator 300, and the negative electrode 200 are stacked to form an electrode assembly 400. The secondary battery cell 1000 is configured by laminating a plurality of electrode bodies 400. By connecting the positive electrode tabs 130 to each other and the negative electrode tab 230, an electrical parallel connection is configured in the secondary battery cell 1000. Although the secondary battery cell 1000 of FIG. 5 is a stacked secondary battery, a wound cylindrical secondary battery or a wound square secondary battery may be applied.

<Electrode mixture layer>
The positive electrode mixture layer 110 has a positive electrode active material capable of absorbing and releasing Li. Examples of the positive electrode active material include LiCo-based oxides, LiNi-based composite oxides, LiMn-based composite oxides, Li—Co—Ni—Mn composite oxides, LiFeP-based oxides, and the like. The negative electrode mixture layer 210 includes a negative electrode active material capable of absorbing and releasing Li. Examples of the negative electrode active material include carbon materials such as natural graphite, soft carbon and amorphous carbon, Si metal, Si alloy, lithium titanate, lithium metal and the like.

In the electrode mixture layer, a positive electrode conductive agent responsible for electron conductivity in the electrode mixture layer, a binder for securing adhesion between materials in the electrode mixture layer, and ion conductivity in the electrode mixture layer A solid electrolyte may be included to secure the

The method for producing the electrode mixture layer is, for example, as follows. First, the material contained in the electrode mixture layer is dissolved in a solvent to form a slurry, which is coated on the electrode current collector. As a coating method, a doctor blade method, a dipping method, a spray method etc. are mentioned, for example. Next, the electrode mixture layer coated on the electrode current collector is dried to remove the solvent. Next, the electrode mixture layer is pressed to secure electron conductivity and ion conductivity in the electrode mixture layer.

<Electrode current collector, electrode tab>
The electrode current collector is electrically connected to the electrode tab. The electrode tab is led out to the side surface of the electrode current collector. In FIG. 6, the electrode mixture layer is not formed on the electrode tab. However, the electrode mixture layer may be formed on the electrode tab as long as the battery performance is not adversely affected.

For the positive electrode current collector 120 and the positive electrode tab 130, an aluminum foil, a perforated aluminum foil having a hole diameter of 0.1 mm to 10 mm, an expanded metal, a foamed aluminum plate or the like can be used. The material may be stainless steel, titanium or the like in addition to aluminum.

For the negative electrode current collector 220 and the negative electrode tab 230, a copper foil, a perforated copper foil with a hole diameter of 0.1 mm to 10 mm, an expanded metal, a foamed copper plate, or the like is used. The material may be stainless steel, titanium, nickel or the like in addition to copper.

The thickness of the electrode current collector and the electrode tab is preferably 10 nm to 1 mm. From the viewpoint of achieving both the energy density of the secondary battery cell 1000 and the mechanical strength of the electrode, about 1 μm to 100 μm is desirable.

<Separator 300>
The separator 300 is formed between the positive electrode 100 and the negative electrode 200, and when the secondary battery cell 1000 is a lithium ion secondary battery, transmits lithium ions to prevent a short circuit between the positive electrode 100 and the negative electrode 200. A microporous film, a solid electrolyte, or the like can be used as a material of which the separator 300 is formed.

As the microporous membrane, polyolefin such as polyethylene and polypropylene and glass fiber can be used. When a microporous film is used for the separator 300, the secondary battery is injected by injecting an electrolyte into the secondary battery cell 1000 from one open side of the exterior body 500 that accommodates the plurality of electrode bodies 400 and the liquid injection hole. An electrolyte is filled in the cell 1000.

The electrolytic solution contains, for example, a solvent and a lithium salt, and serves as a medium for transmitting lithium ions between the positive electrode 100 and the negative electrode 200. Use ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), propylene carbonate, butylene carbonate, γ-butyrolactone, phosphoric acid triester, trimethoxymethane, dioxolane, diethyl ether, sulfolane etc. as a solvent Can. These materials may be used alone or in combination. Examples of the lithium _{_{salt, LiPF 6, LiBF 4, LiClO}} 4, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, lithium bis oxalate borate (LiBOB), lithium imide salt (e.g., lithium bis (Fluorosulfonyl) imide, LiFSI) and the like can be preferably used. You may use these lithium salts individually or in combination of multiple.

As solid electrolytes, sulfides such as Li ₁₀ Ge ₂ PS ₁₂ , Li ₂ S-P ₂ S ₅ , oxides such as Li-La-Zr-O, ionic liquids, molten salts at room temperature, etc. A semisolid electrolyte supported on inorganic particles or the like, a gel electrolyte using a polymer gel as the electrolyte, or the like can be used. When a solid electrolyte is used as the separator 300, the solid electrolyte serves as a medium for transmitting lithium ions between the positive electrode 100 and the negative electrode 200, and the above-described electrolyte solution is basically unnecessary. Serial connection can be configured. However, even if a solid electrolyte is used as the separator 300, an electrolytic solution may be added to the secondary battery cell 1000 as long as an electrical short circuit in the secondary battery cell 1000 can be prevented.

The separator 300 may be formed as a sheet between the positive electrode 100 and the negative electrode 200, or may be formed on the electrode mixture layer by application. The separator 300 may be formed on both sides of the electrode mixture layer, and if the separator 300 is formed between the positive electrode 100 and the negative electrode 200, the separator 300 may be formed on one side of the electrode mixture layer. The thickness of the separator 300 is several nm to several mm in size from the viewpoint of securing the energy density of the secondary battery cell 1000, the electronic insulation, and the like.

<Electrode terminal>
The electrode terminal is electrically connected to the electrode tab. As materials of the positive electrode terminal 150 and the negative electrode terminal 250, metals such as aluminum, copper, nickel and stainless steel can be applied.

<Exterior body 500>
The exterior body 500 accommodates an electrode, a separator 300, and an electrode terminal. In order to electrically connect the electrode terminals to the cell bus bar 600, an opening is formed in the package 500 so as to expose the electrode terminals on the surface on which the electrode terminals of the package 500 are formed. As a material of the exterior body 500, polyolefin, polyvinyl chloride, polyester resin (PET), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyvinylidene fluoride (PVDF), tetrafluoro Soft materials such as ethylene / perfluoroalkyl vinyl ether copolymer (PFA), silicone, ethylene propylene (EP) rubber, neoprene rubber and the like can be applied.

100 positive electrode, 110 positive electrode mixture layer, 120 positive electrode current collector, 130 positive electrode tab, 150 positive electrode terminal 200 negative electrode, 210 negative electrode mixture layer, 220 negative electrode current collector, 230 negative electrode tab, 250 negative electrode terminal 300 separator 400 electrode assembly 500 Exterior body 600 Cell bus bar 700 Buffer material 1000 Secondary battery cell 2000 Secondary battery module 2100 End plate, 2110 End plate opening, 2120 End plate screw 2200 Side plate 2300 Circuit board, 2310 Circuit board recess 2400 First module bus bar, 2450 first Two-module busbar 2500 top plate, 2510 top plate rib, 2520 top plate screw 3000 chassis

Claims

A secondary battery module having a plurality of secondary battery cells, comprising:
The secondary battery cell is configured by laminating an electrode body having a positive electrode, a separator, and a negative electrode,
The secondary battery cell has buffer materials in the in-plane direction end portion in the secondary battery cell and the electrode body,
An end plate sandwiching the plurality of secondary battery cells in the stacking direction of the electrode body, and a side plate sandwiching the plurality of secondary battery cells in the in-plane direction of the electrode body;
And a top plate rib sandwiching the plurality of secondary battery cells in a direction in which the end plate and the side plate are not disposed.
In the secondary battery module of claim 1,
The top plate is a secondary battery module having a top plate rib.
In the secondary battery module of claim 1,
The secondary battery module has a first module bus bar and a second module bus bar for electrically connecting to an adjacent secondary battery module,
The plurality of secondary battery cells have electrode terminals,
The first module bus bar and the second module bus bar are formed in the same plane as the surface on which the electrode terminal is formed.
The first module bus bar protrudes from the secondary battery module,
The second module bus bar is a secondary battery module formed in the secondary battery module.
In the secondary battery module of claim 1,
An end plate opening is formed in the end plate,
The first module bus bar is a secondary battery module penetrating the end plate opening.
In the secondary battery module of claim 1,
And a circuit board formed between the side plate and the plurality of secondary batteries.
In the secondary battery module of claim 5,
The secondary battery module in which the circuit board dent is formed in the said circuit board.
In the secondary battery module of claim 1,
The secondary battery module by which the side plate opening part is formed in the said side plate.
In the secondary battery module of claim 1,
A plurality of cell bus bars electrically connecting the plurality of secondary batteries;
The first module bus bar is a secondary battery module formed between the plurality of cell bus bars.