KR101726755B1 - Top Plate For Plasmatic Battery And Battery Pack Comprising the Same - Google Patents

Abstract

The present invention relates to an electrode assembly having an anode assembly, a separator assembly, and a cathode assembly. The assembly includes a cell case having an open upper end for mounting the electrode assembly therein, A battery cell including a top plate on which a recessed housing part is formed; And a PCM-typed cap including a protection circuit and a safety element electrically connected to the battery cell and mounted on an upper portion of the battery cell.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a top plate for a prismatic battery,

The present invention relates to a top plate for a rectangular battery and a battery pack including the same.

Due to the development of technology and demand for mobile devices, the demand for secondary batteries is also rapidly increasing. Among them, lithium secondary batteries, which have high energy density, high operating voltage and excellent storage and life characteristics, It is widely used as an energy source.

The secondary battery is roughly classified into a cylindrical battery, a prismatic battery and a pouch-shaped battery according to the structural characteristics of the outside and the inside. Among them, the secondary battery can be stacked with a high degree of integration, and prismatic batteries and pouch- .

The secondary battery is also attracting attention as an energy source for electric vehicles and hybrid electric vehicles, which are proposed to solve air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels. Accordingly, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future.

However, the lithium secondary battery contains various combustible materials, and there is a danger of overheating or explosion due to overcharging, overcurrent, other physical external impact, etc., and thus has a serious safety drawback. Therefore, the lithium secondary battery is mounted with a protection circuit module (PCM), which is capable of effectively controlling an abnormal state such as overcharging, connected to the battery cell.

The PCM is composed of a passive element such as a field effect transistor (FET), a voltage detector, a resistor, and a capacitor as a switching element for controlling the conduction of a current. The overcharge, overdischarge, , Reverse voltage, and the like are prevented, thereby preventing deterioration of the battery cell, overheating, deterioration of leakage and charge / discharge characteristics, suppression of electrical performance and physicochemical abnormal behavior, thereby eliminating risk factors and extending service life.

Typically, the PCM is electrically connected to the battery cell via a conductive nickel plate, either by welding or soldering. That is, a nickel plate is welded or soldered to a connecting lead of a PCM, respectively, and then the nickel plate is welded or soldered to an electrode terminal of the battery cell, respectively, thereby connecting the PCM to the battery cell.

In this case, a large number of welding or soldering is required in order to construct the battery pack. Since such a welding or the like requires a very precise work due to the small structure of the secondary battery, the possibility of failure is high. Moreover, the product cost increases due to the addition of such work during the product manufacturing process.

In recent years, in a method of manufacturing PCM by mounting devices on a substrate, a PCM having a very thin thickness is manufactured using a chip on board (PCM) technology to reduce the overall volume of the battery pack, The technology to mount on the top was developed. However, since the PCM manufactured by the chip-on-board technology is expensive compared with the PCM manufactured by the conventional technology, the manufacturing cost of the battery pack is increased.

Therefore, in order to facilitate assembly of the insulating mounting member and the safety element mounted on the upper end of the battery cell, and to prevent the volume of the battery pack from increasing as a whole even when using the battery pack having the PCM manufactured by the prior art, Various techniques for efficiently utilizing the space at the upper end of the battery pack on which the PCM is mounted are being actively researched.

In this regard, Korean Patent Application Publication No. 2007-0097143 discloses an electrode assembly in which two separate electrodes and a separator interposed between the two electrodes are wound and laminated, a can containing the electrode assembly, A secondary battery including a cap assembly coupled to an open top, wherein an insulating case is provided between the electrode assembly and the cap assembly, and the insulating case includes a first groove Is formed on the surface of the secondary battery.

However, the first groove formed in the insulating case prevents bending deformation of the insulating case and minimizes an unnecessary space between the cap assembly and the insulating case. The first groove facilitates assembly of the insulating mounting member and the safety element, There is a problem that it is difficult to efficiently utilize the space at the top of the battery pack. In addition, since a safety element such as a PCM is connected to the electrode terminal of the battery cell through welding or soldering, the problem of complicating the assembling process of the battery pack is not solved.

Accordingly, there is a high need for a technique capable of simplifying the assembling process by reducing the number of members mounted on the upper end of the battery cell and mounting a safety element such as a relatively thick protection circuit module on the top of the battery pack.

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.

The inventors of the present application have conducted intensive research and various experiments and have found that the present invention has a structure in which an upper end is open and a lower end of the upper end of the cell case, A battery cell including a top plate on which a housing part is formed, and a protection circuit and a safety element electrically connected to the battery cell, and a PCM-typed cap And the battery pack having such a structure can greatly simplify the assembling process and can provide an excellent structural stability due to the improved bonding strength and can efficiently utilize the space at the top of the battery pack Respectively.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a battery pack in which a battery cell, a protection circuit module at the top of a battery cell can be stably coupled while efficiently utilizing a space at the top of the battery pack.

In order to accomplish the above object, the present invention provides a battery pack comprising: a cell case having a top opened to mount an electrode assembly having a positive electrode / separator / negative electrode structure therein; A battery cell including a top plate in which a recessed-shaped accommodating portion is recessed inwardly from an upper end of the case; And

A PCM-typed cap including a protection circuit and a safety element electrically connected to the battery cell and mounted on an upper end of the battery cell;

As shown in FIG.

That is, the battery pack according to the present invention is configured such that the top play coupled to the upper end of the cell case includes a recessed-shaped receiving portion recessed inwardly from the upper end of the cell case, And the PCM cap is coupled to the top of the battery cell to provide excellent structural stability, and at the same time, the space at the top of the battery pack can be efficiently utilized.

In one specific example, the cell case is preferably a metal can, for example, by forming work by moving a punch and a die while compressing the material plate on the die surface in the circumferential direction to create sidewalls by drawing work But it is not limited thereto.

The above-mentioned cell case and the top plate are preferably made of aluminum or an aluminum alloy in consideration of ease of processing and mechanical strength of a certain level or more, but are not limited thereto.

The electrode assembly is not particularly limited as long as it has a structure in which a plurality of electrode tabs are connected to form an anode and a cathode. Preferably, the electrode assembly has a jelly-roll structure, a stack structure, a stack- Lamination-stacked structure.

Specifically, the jelly-roll is coated with an electrode active material on a metal foil used as a current collector, dried and pressed, cut in a band shape having a desired width and length, diverged from a cathode and an anode using a separator, To form an elliptical shape on the horizontal cross section.

Further, details of the stack-folding structure of the electrode assembly are disclosed in Korean Patent Application Publication Nos. 2001-0082058, 2001-0082059 and 2001-0082060 of the present applicant, It is incorporated as a reference in the content.

The battery pack is sealed by a top plate in a state where an electrode assembly is mounted together with an electrolyte solution in a cell case to form a battery cell, and a PCM type cap is coupled to the top plate to complete a battery pack.

In one specific example, the depth of the recessed receiving portion formed in the top plate may be formed to a depth in the range of 2 to 20% of the entire length of the cell case, and the engaging portion is protruded on the upper end of the outer circumference of the top plate And a coupling step corresponding to the coupling part is formed on an upper end of the cell case. Thus, the top plate can be stably fixed to the top of the cell case.

In another specific example, the coupling step and the coupling interface may be exposed to the upper surface of the cell case, and the coupling step may be formed in the cell case. In a state where the top plate is mounted on the upper end of the cell case Or may be a structure that is bonded by performing welding to the bonding interface.

With these structures, the top plate can be welded in a state in which the top plate is stably fixed to the upper end of the cell case, and the top plate can be joined to the cell case, so that the assembling process of the battery pack can be simplified.

For example, when at least a part of the PCM-type cap is introduced into the recessed accommodating portion of the top plate, the upper end of the battery cell is inserted into the recessed accommodating portion formed in the top plate, As shown in FIG.

The protection circuit and the safety element included in the PCM-type cap may have a structure in which the protection circuit and the safety element included in the PCM-type cap come in close contact with the inner surface of the recessed- And a substrate including a safety element are integrated into a modular structure.

Further, since the cover for covering the upper end surface of the cell case extends outward on the upper end of the outer circumferential surface of the PCM-type cap, the protection circuit and the safety element are inserted into the recessed- The cover of the cap is brought into close contact with the upper end of the cell case to achieve the engagement.

In addition to the PCM type cap coupled to the upper end of the battery cell, a separate insulating cap (lower end cap) may be mounted on the lower end of the battery cell. Thus, the battery cell can be protected from external impact and maintained in an electrically insulated state. Preferably, the cover film may be attached in a structure that wraps around the joint between the PCM-type cap and the battery cell case.

Such a battery cell may be, for example, a lithium ion battery or a lithium secondary battery in one example, but is not limited thereto.

For reference, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte solution 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 < 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 is 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 300 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.

The non-aqueous 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, etc. 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 device comprising at least one battery pack, wherein the device is a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle) An electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

As described above, in the battery pack according to the present invention, the top plate coupled to the upper end of the cell case is configured to include the recessed-shaped receiving portion that is recessed inward from the upper end of the cell case, It is possible to largely simplify the structure, and it is possible to combine the PCM cap on the top of the battery cell to provide excellent structural stability, and to efficiently utilize the space on the top of the battery pack.

1 is an exploded perspective view of a battery pack according to an embodiment of the present invention;
2 is a vertical sectional view of the top plate portion in the battery pack of Fig. 1;
3 is a vertical cross-sectional view of a portion where the PCM cap is coupled in the battery pack of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

1 is an exploded perspective view schematically illustrating a battery pack according to an embodiment of the present invention.

1, the battery pack 100 includes a cell case 120 having a top opened structure for mounting an electrode assembly (see FIG. 2) having a positive electrode / separator / negative electrode structure therein, The battery cell 110 includes a top plate 130 coupled to an open upper end of the cell case 120 and having a recessed housing part 140 recessed inwardly from an upper end of the cell case 120, And a PCM cap 150 mounted on the upper end of the battery cell. The PCM cap 150 includes a protection circuit and a safety element electrically connected to the cell 110.

The protruding electrode terminal 160 protrudes in the upper direction and the protruding electrode terminal 160 protrudes from the cathode of the battery cell 110. The protruding electrode terminal 160 protrudes upwardly from the recessed housing part 140 formed on the top plate 130, (Not shown), and a recessed housing part 140 excluding the protruding electrode terminal 160 is connected to a positive electrode (not shown) of the battery cell 110. [

The recessed-type storage part 140 is formed at a predetermined depth so that a part of the PCM-type cap 150 including the protection circuit and the safety element can be introduced. The lower end of the PCM- A protruding electrode terminal 160 that is electrically connected to the cathode of the battery cell 110 and a recessed receptacle 140 that is electrically connected to the positive electrode of the battery cell 110 are directly coupled or welded by mechanical fastening. And a connecting member (not shown) to be electrically connected by being joined by the connecting member.

Accordingly, by having a structure in which a lower end portion of the PCM-type cap 150 including the protection circuit and the safety element is coupled to the upper end of the battery cell 110 while being introduced into the recessed-type storage portion 140, The cap 150 can be stably fixed to the upper end of the battery cell 110. In addition, since the step of joining the insulating member and the insulating top cap, which encloses the PCM, can be omitted, the process efficiency can be improved. In addition, in order to mount a plurality of members attached to the upper end of the existing battery cell 110 There is substantially no wasted space, so that it is possible to manufacture a more compact battery pack 100.

2 is a schematic vertical sectional view of a top plate portion in the battery pack of Fig.

2, the top plate 130 is formed with a recessed housing part 140 recessed inwardly from the top of the cell case 120, and the recessed housing part 140 has a protection circuit A depth d of 10% of the entire length of the cell case 120 so that the lower end of the PCM-type cap 150 including the safety element can be mounted on the upper end of the battery cell 110 .

The top plate 130 is coupled to the upper end of the cell case 120 in a state where the electrode assembly 200 is mounted together with the electrolyte solution in the cell case 120, And a coupling step 172 corresponding to the coupling part 171 of the top plate 130 is formed at an upper end of the cell case 120. [

The coupling step 172 is formed such that the coupling interface between the cell case 120 and the coupling part 171 is exposed to the upper end surface of the cell case 120. When the top plate 130 is inserted into the cell case 120, The battery cell 110 is completed by performing welding on the coupling interface.

3 is a vertical cross-sectional view of a portion where the PCM cap is coupled in the battery pack of FIG.

3, the PCM-type cap 150 is inserted into the recessed housing part 140 formed in the top plate 130, and is mounted on the upper part of the battery cell 110, Shaped cap 150 and the lower portion of the PCM-type cap 150 is in close contact with the inner surface of the recessed housing part 140. The lower end of the PCM-shaped cap 150 protrudes downward from the lower end of the PCM- To the top of the top plate 130.

For such a coupling structure, the PCM-type cap 150 has a modular structure in which the substrate including the protection circuit and the safety element (not shown) protrudes to the lower portion of the PCM-type cap 150 on the insulating substrate, It is possible to provide an effect of being stably fixed since it is introduced into the storage portion 140 and mounted.

The cover 180 has a structure in which the cover covering the top surface of the cell case 120 is extended outward from the upper end of the outer circumference of the PCM- The battery pack 100 is formed to have a size that coincides with the outer surface of the cell case 120 and extends in a length L covering the top surface of the battery case 100. The battery pack 100 is mounted on the top of the top plate 130, .

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (19)

A cell case having an open upper end for mounting an electrode assembly having a positive electrode / separator / cathode structure therein, and a recessed-type housing coupled to an open upper end of the cell case and recessed inward from an upper end of the cell case. A battery cell including a top plate on which an electrode is formed; And
A PCM-typed cap including a protection circuit and a safety element electrically connected to the battery cell and mounted on an upper end of the battery cell;
/ RTI >
The cell case is made of a square can made of metal,
The PCM-type cap has a modular structure in which a substrate including a protection circuit and a safety element is integrated with an insulating substrate,
The recessed receiving portion is formed to a predetermined depth so that a part of the PCM-type cap can be introduced,
Wherein a lower end portion of the PCM cap is attached to the upper end of the battery cell while being introduced into the recessed housing portion and the lower portion of the PCM cap is closely attached to the inner face of the recessed housing portion. pack. delete delete The battery pack according to claim 1, wherein the cell case and the top plate are made of aluminum or aluminum alloy, respectively. The battery pack according to claim 1, wherein the electrode assembly is one of a jelly-roll type structure, a stack type structure, a stack-folding type structure, and a lamination-stack type structure. The battery pack according to claim 1, wherein the battery case is sealed by a top plate in a state that the electrode assembly is mounted on the cell case together with the electrolyte, and a PCM-type cap is coupled to the top plate. The battery pack according to claim 1, wherein the depth of the recessed-type storage portion is a depth in a range of 2 to 20% of the total length of the cell case. The battery pack according to claim 1, wherein an engaging portion protrudes from an upper end of an outer circumferential surface of the top plate on a vertical cross section, and a coupling step corresponding to the engaging portion is formed on an upper end of the cell case. 9. The battery pack according to claim 8, wherein a coupling step is formed in the cell case in such a shape that the coupling interface with the coupling part is exposed to the upper surface of the cell case. The battery pack according to claim 9, wherein welding is performed to the coupling interface to join the top plate to the cell case. delete delete The battery pack according to claim 1, wherein a cover covering an upper end surface of the cell case extends outward on an upper end of an outer circumferential surface of the PCM-type cap. 14. The battery pack according to claim 13, wherein an extension size of the cover is such that an end portion of the cover matches the outer surface of the cell case. delete The battery pack according to claim 1, wherein an outer film is attached to an outer surface of the battery cell. The battery pack according to claim 1, wherein the battery cell is a lithium secondary battery. A device, comprising at least one battery pack according to any one of claims 1, 4 to 10, 13, 14, 16 and 17. 19. The method of claim 18, wherein the device is selected from the group consisting of a mobile phone, a portable computer, a smart phone, a smart pad, a netbook, a wearable electronic device, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, Device. ≪ / RTI >

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