KR20180063454A - Battery Module Having Module Compression Limiting Structure - Google Patents

Abstract

The present invention provides a battery module capable of preventing cartridges and battery cells from being compressed and preventing the battery module from being damaged due to a gap between the battery cells and a stacking tolerance even when an external impact is applied to the battery module. The battery module comprises: a battery cell assembly having a plurality of battery cells arranged side by side so as to be in close contact with or adjacent to each other; and a pair of end plates fixed to individually surround the outermost battery cells of the battery cell assembly. The battery cell assembly and the end plates are coupled and fixed by a plurality of fastening members in an arrangement direction of the battery cells. The fastening member consists of a structure in which both side end parts support the end plates in the arrangement directions of the battery cells so as to prevent the end plate from compressing the battery cell assembly by the external impact and prevent the battery cell assembly from being compressed.

Description

(Battery Module Having Module Compression Limiting Structure)

The present invention relates to a battery module including a module compression prevention structure.

In recent years, the demand for environmentally friendly alternative energy sources has become an indispensable factor for the future, as the increase in the price of energy sources due to depletion of fossil fuels and the interest in environmental pollution are amplified. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, as technology development and demand for mobile devices increase, the demand for batteries as energy sources is rapidly increasing. Recently, the use of secondary batteries as a power source for electric vehicles (EV) and hybrid electric vehicles (HEV) In addition, the use area has been expanded for use as a power auxiliary power source through a grid, and accordingly, a lot of researches on a battery that can meet various demands have been conducted.

On the other hand, in small mobile devices, one or two or more battery cells are used per device, while a middle- or large-sized battery module such as an automobile is used for a large-capacity battery module in which a plurality of battery cells are electrically connected

In the case of such a battery module, devices that are exposed to various operating environments such as electric bicycles and electric vehicles must stably protect the components constituting the battery pack against the external environment and realize high output and large capacity by using a plurality of batteries The safety aspect is also important.

The battery module has a structure in which a plurality of battery cells are stacked so as to be laterally arranged in a structure fixed to the respective cartridges. Accordingly, when an external impact is applied from the outside of the battery module to the side of the battery cells, the cartridges and the battery cells are compressed due to the gap and the lamination tolerance to damage the refrigerant channel, short circuit inside the cell, electrical connection damage, And the like.

Therefore, there is a high need for a technique capable of fundamentally solving such problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

Specifically, it is an object of the present invention to provide a battery module capable of preventing the cartridges and the battery cells from being damaged due to the gap between the battery cells and the lamination tolerance even when an external impact is applied to the battery module, will be.

According to an aspect of the present invention,

A battery cell assembly having a plurality of battery cells arranged side by side so as to be in close contact with or adjacent to each other; And

A pair of end plates fixed to surround the outermost battery cells of the battery cell assembly;

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The battery cell assembly and the end plates are coupled and fixed by a plurality of fastening members in an array direction of the battery cells, and the fastening member presses the battery cell assembly by the external impact to compress the battery cell assembly Side end portions of the battery cells may be structured to support the end plates in the arranging direction of the battery cells.

Therefore, in the battery module according to the present invention, the battery cell assembly and the end plates are coupled and fixed by a plurality of fastening members in the direction of arrangement of the battery cells, and the fastening member presses the battery cell assembly Side end portions support the end plates in the arranging direction of the battery cells so as to prevent the battery cell assembly from being compressed. Therefore, even when an external impact is applied to the battery module, the gap between the battery cells and the stacking tolerance It is possible to prevent the cartridges and the battery cells from being compressed and damaging the battery module.

In one embodiment of the present invention, the battery cell may be a pouch-shaped battery cell in which an electrode assembly is embedded in a case of a laminate sheet including a resin layer and a metal layer.

The electrode assembly may have a folding structure, a stacking structure, or a stacking / folding structure, or a lamination / stacking structure.

The electrode structures of the folding type, the stacking type, the stacking / folding type, and the lamination / stacking type will be described in detail as follows.

First, a unit cell of a folding structure can be produced by coating a mixture containing an electrode active material on each metal current collector, placing the separator sheet between a cathode and an anode in the form of a sheet dried and pressed, and winding .

The unit cells of the stacked structure are formed by coating each electrode collector with an electrode mixture, drying and pressing the separator, and separating the positive and negative plates with a predetermined size corresponding to the positive and negative plates, And then laminating them.

The unit cell of the stack / folding type structure includes two or more unit cells in which the anode and the cathode face each other and in which two or more electrode plates are stacked, and the unit cells are wound with at least one separating film in a non- Or by bending the separation film to a size of the unit cell and interposing it between the unit cells.

In some cases, the positive electrode and the negative electrode face each other, and one or more single electrode plates may be further included between any unit cells and / or an outer surface of the outermost unicell.

The unit cell may be an S-type unit cell in which the outermost electrode plates on both sides have the same electrode, and a D-type unit cell in which the outermost electrode plates on opposite sides have opposite electrodes.

The S type unit cell may be an SA type unit cell in which the outermost electrode plates on both sides are the anode, and an SA type unit cell in which the outermost electrode plates on both sides are the cathodes.

The unit cells of the lamination / stacked structure are obtained by coating each metal current collector with an electrode mixture, drying, pressing and cutting to a predetermined size, sequentially forming a negative electrode from the bottom, a separator, And a separator is laminated thereon.

The battery case may include a pouch-shaped case having a laminate structure including a metal layer and a resin layer.

As a specific example of the battery case, the battery case is made of a laminate sheet including a resin outer layer of excellent durability, a metal layer of barrier property, and a heat-fusible resin sealant layer, and the resin sealant layers are heat- .

Since the resin outer layer must have excellent resistance from the external environment, it is necessary to have a tensile strength and weather resistance higher than a predetermined level. In this respect, polyethylene terephthalate (PET) and stretched nylon film can be preferably used as the polymer resin of the outer resin layer.

The barrier metal layer may preferably be made of aluminum so as to exhibit a function of improving the strength of the battery case, in addition to a function of preventing foreign matter such as gas or moisture from leaking or leaking.

The resin sealant layer may preferably be a polyolefin resin having low heat absorbability (thermal adhesiveness), low hygroscopicity to suppress penetration of an electrolyte solution, and not being swollen or eroded by an electrolytic solution, Preferably, lead-free polypropylene (CPP) can be used.

In one specific embodiment of the battery cell assembly, the battery cell assembly may have a structure in which the battery cells are stacked in a side-by-side configuration in which the battery cells are fixed to the respective cartridges.

Specifically, the cartridge may include a frame for fixing outer peripheral sealing portions of the battery cells located on both sides.

In addition, the cartridge and the end plate may be provided with fasteners through which fastening members for fastening the battery cell assembly are inserted.

More specifically, the fasteners may be formed on fastening protrusions extending outward on both sides of the upper and lower ends of the cartridge and the end plate, respectively.

As one specific embodiment of the fastening member,

The fastening member has a bar shape and includes a body portion that is fastened through fastening holes of the cartridge and a support portion that is formed at both ends of the body portion and is inserted into the fastening hole of the end plate And the like.

Specifically, the outer diameter of the support portion may be smaller than the outer diameter of the body portion, and the body portion and the support portion may form a stepped structure in a vertical section.

More specifically, the outer diameter of the support portion may be relatively smaller than the inner diameter of the fastener of the end plate, and the outer diameter of the body portion may be formed to be relatively larger than the inner diameter of the fastener of the end plate.

Accordingly, even if the end plate is pressed toward the battery cell assembly by an external force, the end plate is supported by the main body of the fastening member, thereby securing the structural safety of the battery module.

The outer diameter of the support portion may be 50% to 80% of the outer diameter of the body portion.

When the outer diameter of the support portion is less than 50% of the outer diameter of the body portion, the engagement force between the support portion and the end plate may be weakened. On the other hand, when the outer diameter of the support portion exceeds 80% of the outer diameter of the main body portion, the area of contact between the main body portion and the end plate is reduced, so that the end plate may not be sufficiently supported during an external impact.

As one specific example of the support portion, a screw thread may be formed on the outer surface of the support portion, and the support portion may be configured to be engaged with the nut in a state of being inserted into the fastener of the end plate.

Specifically, the support portion may have a stepped bolt structure.

In one embodiment of the present invention, a depression groove having a predetermined depth may be formed at the center of the main body along the longitudinal direction. The indentation groove facilitates gripping of the fastening member in the process of assembling the fastening member by the operator, thereby facilitating the assembling process and reducing the assembling time.

Meanwhile, the type of the battery cell constituting the battery module according to the present invention is not particularly limited, but specific examples thereof include a lithium ion battery having advantages such as high energy density, discharge voltage, and output stability, a lithium ion polymer battery And the like.

Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane and the separation film are interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 130 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

Further, in one specific example, in order to improve the safety of the battery, the separation membrane and / or the separation film may be an organic / inorganic composite porous SRS (Safety-Reinforcing Separators) separation membrane.

The SRS separator is manufactured by using inorganic particles and a binder polymer on the polyolefin-based separator substrate as an active layer component. In addition to the pore structure contained in the separator substrate itself, the SRS separator is formed by interstitial volume between inorganic particles And has a uniform pore structure.

The use of such an organic / inorganic composite porous separator has the advantage of suppressing an increase in thickness of the cell due to swelling at the time of chemical conversion compared with the case of using a conventional separator, When a gelable polymer is used when liquid electrolyte is impregnated, it can also be used as an electrolyte.

In addition, the organic / inorganic composite porous separator can exhibit excellent adhesion characteristics by controlling the contents of the inorganic particles and the binder polymer in the separator, so that the cell assembly process can be easily performed.

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles usable in the present invention are not particularly limited as long as the oxidation and / or reduction reaction does not occur in the operating voltage range of the applied battery (for example, 0 to 5 V based on Li / Li +). Particularly, when inorganic particles having an ion-transporting ability are used, the ion conductivity in the electrochemical device can be increased and the performance can be improved. Therefore, it is preferable that the ionic conductivity is as high as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse the particles at the time of coating, and there is a problem of an increase in weight during the production of the battery. In the case of an inorganic substance having a high dielectric constant, dissociation of an electrolyte salt, for example, a lithium salt, in the liquid electrolyte also contributes to increase ionic conductivity of the electrolyte.

The nonaqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The present invention also provides a battery pack including the battery module.

The present invention also provides a device including the battery pack, wherein the device may be any one selected from the group consisting of an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

Since the devices are well known in the art, a detailed description thereof will be omitted herein.

As described above, in the battery module according to the present invention, the battery cell assembly and the end plates are coupled and fixed by a plurality of fastening members in the arrangement direction of the battery cells, Since the end portions of both end portions support the end plates in the arrangement direction of the battery cells so as to prevent the battery cell assembly from being compressed by pressing the cell assembly, even if an external impact is applied to the battery module, The gap and the lamination tolerance can prevent the cartridges and the battery cells from being compressed and damaging the battery module.

1 is a side view of a battery module according to one embodiment of the present invention;
2 is an exploded perspective view of the battery module of Fig. 1;
Figure 3 is an exploded side view of the battery module of Figure 1;
4 is a vertical cross-sectional view of the 'A' region of the battery module of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings according to the embodiments of the present invention, but the scope of the present invention is not limited thereto.

FIG. 1 is a side view of a battery module according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the battery module of FIG. 1, and FIG. 3 is an exploded side view of the battery module of FIG. And FIG. 4 is a vertical sectional view of the 'A' portion of the battery module of FIG.

1 to 4, the battery module 100 includes a battery cell assembly 110 and an end plate 130.

The battery cell assembly 110 and the end plates 130 are coupled and fixed by four fastening members 200 in the arrangement direction of battery cells (not shown).

The fastening member 200 is formed so that the end plates 130 are pressed against the battery cell assembly 110 by the external impact to prevent the battery cell assembly 110 from being compressed, And supports the end plates 130.

Specifically, the battery cell assembly 110 has a structure in which the battery cells are stacked so as to be laterally arranged in a structure fixed to the cartridge 111, and the cartridge 111 has a structure in which the outer peripheral sealing portions As shown in Fig.

Fasteners 112 and 132 are inserted into the cartridge 111 and the end plate 130, respectively, in which fastening members 200 for fastening the battery cell assembly 110 are inserted. The fastening tools 112 and 132 are formed on fastening protrusions 113 and 133 which extend outward on both sides of the upper and lower ends of the cartridge 111 and the end plate 130, respectively.

The fastening member 200 is formed in a bar shape and includes a main body 210 which is fastened through a fastening hole 112 of the cartridge 111 and an end plate 130 which is formed at both ends of the main body 210, And a supporting part 220 inserted into the fastening hole 132 of the fastening part.

The outer diameter P2 of the support portion 220 is a relatively small size of the outer diameter P1 of the main body portion 210 and the main body portion 210 and the support portion 220 form a stepped structure in a vertical section .

The outer diameter of the support portion 220 is 70% of the outer diameter of the body 210.

A screw thread is formed on the outer surface of the support part 220. The support part 220 is engaged with the nut 300 in a state of being inserted into the fastener 132 of the end plate 130 and fastened.

A depression 211 having a predetermined depth is formed in the center of the main body 210 along the longitudinal direction.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (15)

A battery cell assembly having a plurality of battery cells arranged side by side so as to be in close contact with or adjacent to each other; And
A pair of end plates fixed to surround the outermost battery cells of the battery cell assembly;
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The battery cell assembly and the end plates are coupled and fixed by a plurality of fastening members in an array direction of the battery cells, and the fastening member presses the battery cell assembly by the external impact to compress the battery cell assembly Wherein the end portions of the battery cells are configured to support the end plates in the direction of arrangement of the battery cells. The battery module according to claim 1, wherein the battery cell is a pouch-shaped battery cell having an electrode assembly embedded in a case of a laminate sheet including a resin layer and a metal layer. The battery module according to claim 1, wherein the battery cell assembly is stacked such that the battery cells are respectively arranged on the cartridge in a side-by-side configuration. The battery module according to claim 3, wherein the cartridge comprises a frame for fixing outer peripheral sealing portions of the battery cells located on both sides. The battery module according to claim 3, wherein the cartridge and the end plate are each provided with fasteners through which fastening members for fastening the battery cell assembly are inserted. The battery module according to claim 5, wherein the fasteners are formed on fastening protrusions extending outward on both sides of the top and bottom ends of the cartridge and the end plate, respectively. [6] The apparatus of claim 5, wherein the fastening member has a bar shape,
A body portion which is fastened through a fastener of the cartridge; And
A support portion formed at both ends of the body portion and inserted into fastening holes of the end plate;
The battery module comprising: The battery module according to claim 7, wherein an outer diameter of the support portion is smaller than an outer diameter of the body portion, and the body portion and the support portion form a stepped structure in a vertical section. The battery module according to claim 8, wherein the outer diameter of the support portion is relatively smaller than the inner diameter of the fastener of the end plate, and the outer diameter of the body portion is relatively larger than the inner diameter of the fastener of the end plate. The battery module according to claim 8, wherein an outer diameter of the support portion is 50% to 80% of an outer diameter of the body portion. 8. The method of claim 7,
A screw thread is formed on an outer surface of the support portion;
And the support portion is engaged with the nut in a state of being inserted into the fastening hole of the end plate. 12. The battery module according to claim 11, wherein the support portion is formed in a stepped bolt structure. [8] The battery module of claim 7, wherein a depression is formed in the center of the main body at a predetermined depth along the longitudinal direction. A battery pack comprising the battery module according to any one of claims 1 to 13. A device as claimed in claim 14 comprising as a power source of the battery pack.

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