KR20180107468A - Battery Pack Having Bus-bar - Google Patents

Abstract

The present invention relates to a battery pack which has at least two integrated bus bars for electrically connecting unit modules. Each of the unit modules includes: a box-shaped module case having an accommodating part for accommodating battery cells; at least two battery cells stacked in one direction and accommodated in the module case; and a module cover which is made of an insulating material and covers the open upper part of the module case. The integrated bus bar performs electrical connection between the battery cells of two or more unit modules.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery pack having an integrated bus bar (Battery Pack Having Bus-bar)

The present invention relates to a battery pack including an integrated bus bar.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been extensively used as an energy source or an auxiliary power device for wireless mobile devices. In addition, the secondary battery is an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (HEV), and the like, which are proposed as solutions for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels (Plug-In HEV), etc., and is used as an energy storage configuration of a standby power supply device in preparation for an emergency such as a power failure.

In the case of small mobile devices, one or two or more battery cells are used per device, and a large-capacity device such as a spare power supply device or a car is used for a battery module in which a plurality of battery cells are electrically connected due to the necessity of high- do.

Since the battery module is preferably made as small in size and weight as possible, a prismatic battery, a pouch-shaped battery, or the like, which can be filled with a high degree of integration and has a small weight to capacity, is mainly used as a battery cell (unit cell) of a middle- or large- . In particular, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a lot of attention due to its advantages such as small weight, low manufacturing cost, and easy shape deformation.

On the other hand, in order for the battery module of the related art to provide the output and capacity required by a predetermined device or device, a plurality of battery cells must be electrically connected in series or parallel manner, and the greater the capacity of the battery module, It should be easy and stable structure. Particularly, in the prior art, a plurality of battery cells are used to constitute a battery module, and a battery pack having a plurality of such configurations is manufactured using the battery modules as one unit.

However, in the case of such a battery pack, it is inevitable that a bus bar for electrical connection between the battery cells is provided in the battery module, and a separate bus bar for electrical connection between the battery modules is similarly provided. A large number of members are generally required for mechanical fastening and electrical connection of these members, and the process of assembling these members is very complicated and has a problem of raising the manufacturing cost.

Further, since such a battery pack includes a plurality of battery modules, it is necessary to detect the voltage of each battery module in order to prevent overvoltage, overcurrent, or overheating of the battery cells. There was a need. Accordingly, the mounting or connection of the plurality of detecting means is complicated as the capacity of the battery module is increased, and there is also a risk of short circuit due to a large number of wires for the assembly process.

Therefore, there is a high need for a technique that can effectively solve the problems of the prior art described above.

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. As will be described later, when the battery pack of the present invention performs electrical connection between battery cells of two or more unit modules using the integrated bus bar , It has been confirmed that the electrical connection between the battery cells in the battery module and the electrical connection between the battery modules can be performed at the same time, and the present invention has been accomplished.

In order to achieve the above object, a battery pack according to the present invention includes:

Wherein at least two integrated bus bars form an electrical connection between the unit modules,

Wherein each of the unit modules comprises:

A box-shaped module case having a housing part for housing therein the battery cells and an open top;

At least two battery cells stacked in one direction and housed in a module case; And

A module cover which is made of an insulating material and covers and covers the open top of the module case;

And,

And the integrated bus bar performs electrical connection between the battery cells of the two or more unit modules.

Therefore, the battery pack according to the present invention performs electrical connection between the battery cells of two or more unit modules using the integrated bus bar, thereby electrically connecting the battery cells to each other and electrically connecting the battery modules to each other Therefore, a separate bus bar for electrical connection between the battery modules can be omitted. This solves the problem of raising the manufacturing cost caused by a large number of bus bars required for the battery pack of the related art, and further, It is not necessary to provide detection means for voltage detection for each battery module, thereby increasing the space efficiency of the battery module, simplifying the assembling process, and omitting a plurality of wires, thereby reducing the risk of short circuit.

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

Specifically, the battery cell has sealing portions formed by thermal fusion at the outer periphery thereof. The anode terminal protrudes from the inside of the sealing portion to the outside at one side sealing portion, and the cathode terminal is connected to the inside of the sealing portion So as to protrude outwardly.

The battery cell may be a plate-shaped battery cell having electrode terminals formed on one side of the battery cell. Specifically, the plate-shaped battery cell may have a rectangular shape having a pair of long sides and a pair of short sides in a plan view, and the positive and negative terminals of the battery cell may be located on one side.

In one specific example, the electrode terminals of the battery cell may be protruded from one side of the battery cell in the form of a strip.

In one specific example, the module cover may be formed with through-holes at positions corresponding to the electrode terminals for inserting the electrode terminals of the battery cells. The through-hole may have a shape corresponding to a cross-sectional shape of the electrode terminal so that the electrode terminal can be inserted.

Also, the electrode terminals may be bent at least once on the upper surface of the module cover to be inserted into the through-hole of the module cover, and one end of the electrode terminal is inserted into the through-hole of the module cover, And may be joined to the outer upper surface. Specifically, an adhesive may be used for joining a part of the electrode terminal with an outer upper surface of the module cover.

In one specific example, the integrated bus bar may be structured to be coupled to a portion of the electrode terminal inserted and fixed in the through-hole of the module cover. The welding method can be used as long as it is a known method, and examples thereof include ultrasonic welding, laser welding, arc welding, and the like.

In one specific example, the integrated bus bar may have a strip shape elongated in one direction, and the integrated bus bar may electrically connect any one of the polarity electrode terminals of the battery cells housed in the module case have.

In one specific example, the module cover may include a fastening member for engaging with an upper portion of the module case, and fasteners into which the fastening member is inserted to fasten the module cover to the module case may be formed . The fasteners may be formed at a portion near the edge of the module cover or at a rim portion. Specifically, the fastening member may be a fastening bolt.

In one specific example, the rim of the module cover may be a structure that is bent and projected downwardly to receive a top portion of the module case.

In one specific example, the unit modules may have a structure in which the battery cells are disposed facing each other in the stacking direction. The integrated bus bar may have a length corresponding to the total length of the unit cells in the stacking direction of the battery cells.

In one specific example, the battery management system may further include a battery management system (BMS) disposed at one side of the unit modules, for monitoring a voltage of the battery cells and controlling an electric cutoff from an external device.

In addition, the BMS may be electrically connected to the integrated bus bar for voltage detection of the battery cells. Therefore, the integrated bus bar according to the present invention makes electrical connection between the battery cells of the battery modules and the other connection members, thereby enabling the voltage detection of the battery cells of the battery modules.

In one specific example, the battery cell may be a lithium secondary battery of high energy density, discharge voltage, and output stability. Other components of the lithium secondary battery according to the present invention will be described in detail below.

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

The anode may be prepared, for example, by coating a mixture of a cathode active material, a conductive material and a binder on a cathode current collector, followed by drying. If necessary, a filler may be further added to the mixture.

The cathode active material is a material capable of causing an electrochemical reaction. Examples of the lithium transition metal oxide include lithium cobalt oxide (LiCoO ₂ ) containing two or more transition metals and substituted with one or more transition metals, lithium Layered compounds such as nickel oxide (LiNiO ₂ ); Lithium manganese oxide substituted with one or more transition metals; Formula _{LiNi 1-y M y O 2} ( where, M = Co, Mn, Al , Cu, Fe, Mg, B, Cr, Zn or Ga and Lim, 0.01≤y≤0.7 include one or more elements of the element) A lithium nickel-based oxide represented by the following formula: _{Li 1 + z Ni 1/3 Co 1/3} Mn 1/3 O 2, Li 1 + z Ni 0.4 Mn 0.4 Co 0.2 O 2 , such as _{Li 1 + z Ni b Mn c} Co 1- (b + c + d _{) M d O (2-e} ) A e ( where, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2 , 0≤e≤0.2, b + c + d <1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl; lithium nickel cobalt manganese composite oxide; And the formula _{Li 1 + x M 1-y} M 'y PO 4-z X z ( wherein, M = a transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S or N, and -0.5? X? +0.5, 0? Y? 0.5, and 0? Z? 0.1), but the present invention is not limited thereto.

The conductive material is usually added in an amount of 1 to 20 wt% 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 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.

Further, the negative electrode is prepared, for example, by coating a negative electrode current collector with a mixture of a negative electrode active material, a conductive material and a binder, and drying the mixture. Optionally, a filler may be further added to the mixture. The negative electrode active material may be at least one selected from the group consisting of graphite carbon, coke carbon, and hard carbon.

Since the configurations of the lithium secondary battery described above are well known in the art, a detailed description thereof will be omitted herein.

As described above, when the battery pack according to the present invention performs electrical connection between the battery cells of two or more unit modules using the integrated bus bar, a separate bus bar for electrical connection between the battery modules can be omitted In addition, it is unnecessary to provide detection means for detecting the voltage of each battery module, and it is unnecessary to provide a detecting means for detecting the voltage of each battery module. The space efficiency can be improved, the assembly process can be simplified, and the number of wires can be omitted, thereby reducing the risk of short circuit.

1 is a perspective view illustrating battery packs according to an embodiment of the present invention;
2 is an exploded perspective view illustrating battery packs according to one embodiment of the present invention;
3 is a side view of battery packs according to one embodiment of the present invention;
4 is a sectional view taken along the line AA 'of the battery pack of FIG. 3;
Fig. 5 is an enlarged view of a part B of the battery pack of Fig. 4;

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

FIG. 1 is a perspective view showing battery packs according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view illustrating battery packs according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a battery pack 101 and a battery pack 102 according to the present invention are shown. The battery pack 101 includes unit buses 141 and 142, 191, 192, 193, and 194, respectively. The integrated bus bar 141 performs electrical connection between the battery cells 120 of the four unit modules 191, 192, 193, and 194.

Each of the unit modules 191, 192, 193, and 194 includes a box-shaped module case 110 having a housing part 112 for housing therein the battery cells 120 therein, And a module cover 130 formed of an insulating material and covering the open upper portion of the module case 110. The module cover 110 includes a module cover 110,

FIG. 3 is a cross-sectional view of the battery pack of FIG. 3, and FIG. 5 is a cross-sectional view of a portion B of the battery pack of FIG. An enlarged view is shown.

Referring to FIGS. 3 to 5, the battery cell 120 is a plate-shaped battery cell 120 having electrode terminals 121 and 122 formed on one side surface of the battery cell 120. The electrode terminals 121 and 122 of the battery cell 120 are protruded from one side of the battery cell 120 in the form of a strip.

The module cover 130 is formed with through-holes 132 at positions corresponding to the electrode terminals 122 for inserting the electrode terminals 121 and 122 of the battery cell 120, respectively. The through-hole 132 has a shape corresponding to the cross-sectional shape of the electrode terminal so that the electrode terminal 122 can be inserted.

The electrode terminals 121 and 122 are bent so as to be in contact with the upper surface 134 of the module cover 130 so as to be inserted into the through hole 132 of the module cover 130, One end of the module cover 130 is inserted into the through hole 132 of the module cover 130 and is joined to the outer upper surface 134 of the module cover 130. An adhesive agent (not shown) for bonding to one portion of the electrode terminal 122 is applied to the outer upper surface 134 of the module cover 130.

The integrated bus bar 141 is connected to a portion 124 of the electrode terminal 122 which is fixedly inserted into the through hole 132 of the module cover 130.

The integrated bus bar 141 is connected to one of the polarity electrode terminals 122 of the battery cells 120 housed in the module case 110, All electrically connected.

The module cover 130 is formed with fasteners 136 for fastening members (not shown) to be fixed to the module case 110.

The rim 137 of the module cover 130 is bent and projected in the downward direction T to receive the upper portion 115 of the module case 110.

Referring again to FIG. 2, the unit modules 191, 192, 193, and 194 are disposed facing each other in the stacking direction of the battery cells 120. The integrated bus bar 141 is formed to have a length corresponding to the total length of the unit cells 191, 192, 193, and 194 in the direction S in which the battery cells 120 are stacked.

Referring again to FIG. 4, the BMS 200 disposed at one side of the unit modules 191, 192, 193, and 194 and monitoring the voltage of the battery cells 120 and controlling the cut- .

In addition, the BMS 200 is electrically connected to the integrated bus bar 141 for detecting the voltage of the battery cells 120

As described above, in the case where the battery pack according to the present invention performs electrical connection between the battery cells of two or more unit modules using the integrated bus bar, a separate bus bar for electrical connection between the battery modules may be omitted The present invention solves the problem of raising the manufacturing cost caused by a large number of bus bars that have been consumed in the battery pack of the related art and further eliminates the necessity of providing detection means for detecting the voltage of each battery module, The efficiency can be improved, the assembly process can be simplified, and the number of wires can be omitted, thereby reducing the risk of short circuit.

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)

1. A battery pack comprising: at least two unit bus bars for electrically connecting unit modules,
Wherein each of the unit modules comprises:
A box-shaped module case having a housing part for housing therein the battery cells and an open top;
At least two battery cells stacked in one direction and housed in a module case; And
A module cover which is made of an insulating material and covers and covers the open top of the module case;
And,
Wherein the integrated bus bar performs electrical connection between battery cells of two or more unit modules. The battery pack according to claim 1, wherein the battery cell is a pouch-shaped battery cell in which an electrode assembly is embedded in a battery case of a laminate sheet. The battery pack according to claim 1, wherein the battery cell is a plate-shaped battery cell having electrode terminals formed on one side of the battery cell. The battery pack according to claim 3, wherein the electrode terminals of the battery cell protrude in a strip form. The battery pack according to claim 1, wherein the module cover is formed with through-holes at positions corresponding to the electrode terminals for inserting the electrode terminals of the battery cells. The battery pack according to claim 5, wherein the electrode terminals are bent at least once on the upper surface of the module cover to be inserted and fixed in the through-hole of the module cover. 7. The battery pack according to claim 6, wherein one end of the electrode terminal is inserted into a through hole of the module cover and is joined to the upper surface of the module cover. 7. The battery pack according to claim 6, wherein the integrated bus bar is coupled to a portion of an electrode terminal inserted and fixed in a through hole of a cover of the unit module. The battery pack according to claim 1, wherein the integrated bus bar has a strip shape elongated in one direction, and electrically connects the electrode terminals of any one of the battery cells to each other. The battery pack according to claim 1, wherein the module cover includes a fastening member for engaging with an upper portion of the module case. The battery pack according to claim 1, wherein a rim of the module cover is bent and projected downward to receive a top portion of the module case. The battery pack according to claim 1, wherein the unit modules are disposed facing each other in a stacking direction of the battery cells. 13. The battery pack according to claim 12, wherein the integrated bus bar is formed to have a length corresponding to the entire length of the unit cells in the stacking direction of the battery cells. The battery pack according to claim 1, further comprising a battery management system (BMS) disposed at one side of the unit modules, for monitoring a voltage of the battery cells and controlling an electric cutoff from an external device. 15. The battery pack according to claim 14, wherein the BMS is electrically connected to the integrated bus bar for voltage detection of the battery cells.

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