KR20150121518A - Battery module and battery pack for guarantee at safety for short circuit - Google Patents

Abstract

The present invention is to improve the safety and reliability of a battery module for a secondary battery by physically blocking a line before damage to a battery cell is generated in the case of a short circuit while maintaining the performance of a battery pack unlike conventional ones, thereby preventing risks such as explosion and a fire caused by the damage to the battery cell, in advance. To achieve the purpose, the battery module, which comprises multiple battery cells; and multiple bus bars for electrically connecting the battery cells, provides a battery module for a secondary battery wherein: a bus bar which must be physically separated before the battery cell is damaged in the case of a short circuit, from among the multiple bus bars is made of different types of materials having a lower melting point than the melting point of the other bus bars; and in the case of occurrence of short circuit, the bus bar on one side is melted first to be physically separated before the battery cell is damaged.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery module and a battery pack,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery module and a battery pack for a secondary battery, and more particularly, to a battery module and a battery pack, such as an electric vehicle, The present invention relates to a technique for improving the safety and reliability of a battery module and a battery pack by physically cutting off a line before a cell is damaged, thereby preventing explosion and ignition.

Generally, unlike a primary cell, a secondary battery can be charged and discharged, and is being applied to various fields such as a digital camera, a mobile phone, a notebook, and an electric vehicle, and active research is underway. Examples of the secondary battery include a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery.

The lithium ion battery and the lithium ion polymer battery have the same structure except that the properties (liquid / solid) of the electrolyte are different. In addition, depending on the battery, the material of the electrolyte and the electrode may be slightly different. In the case of other secondary batteries, the basic principle and structure are the same except that the materials used for the electrodes or the electrolyte are different.

Recently, a battery pack capable of charging and discharging has been widely used as an energy source for wireless mobile devices. It is widely used as an energy source for electric vehicles (for example, EV, a hybrid electric vehicle (HEV), and an electric bicycle (EBIKE).

A lithium secondary battery is mainly used as a power source of an electric vehicle or a hybrid vehicle, and a large capacity such as a motor drive is required. Therefore, a battery module comprising a plurality of battery modules electrically connected to each other in series or parallel, Of the battery pack is generally used.

That is, in small mobile devices, one or two or more battery cells are used per device, and a large-sized device such as an electric car or an electric bicycle is electrically connected to a large number of high-output battery cells primarily A battery module is constructed, and a plurality of battery modules are electrically connected again according to the required specifications to constitute a battery pack having a high output capacity.

On the other hand, when the decomposition reaction is continuously induced in an abnormal operating state such as overcharge, over-discharge, high-temperature exposure, electrical short-circuit, etc., the secondary battery generates heat and gas, and the decomposition reaction at the high- May cause ignition or explosion.

Particularly, such a problem can lead to a serious serious accident in the case of a high output large capacity battery pack having a plurality of battery cells.

The high power, large capacity battery pack has a plurality of battery cells or unit modules in a frame having a predetermined space, and the battery cells or the unit modules may swell, resulting in an abrupt pressure rise inside the case.

To solve such a problem, a battery module for a secondary battery is provided with a fuse, a bimetal, and a BMS (BMS), but sufficient safety can not be secured by the above configuration.

That is, in a normal state, the BMS can detect an electrical fault condition (overdischarge, overcharge, overcurrent) and secure the safety by controlling the entire module. However, if the BMS is not operated in an abnormal state, There is a problem that the risk of explosion or explosion of the battery cells is increased.

Meanwhile, in order to secure the safety of the battery module, the protection device such as the fuse, the bimetal, and the BMS is provided to increase the current path resistance of the battery module. As a result, There is a disadvantage that it causes deterioration.

Korean Patent Publication No. 10-2013-0080023 (2013.07.11.) Korean Patent Publication No. 10-2013-0059301 (June 3, 2013) Korean Patent Publication No. 10-2014-0018079 (Feb.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a battery pack capable of preventing a battery from being damaged before a short- The present invention provides a battery module for a secondary battery and a battery pack having improved safety and reliability by preventing a danger such as explosion and ignition.

According to an aspect of the present invention, there is provided a battery module including a plurality of battery cells and a plurality of bus bars for electrically connecting the battery cells to each other; Wherein a bus bar which is to be physically separated from the plurality of bus bars before a battery cell is short-circuited is formed of a dissimilar material having a low melting point in comparison with the other bus bars. to provide.

In the above-described configuration, the bus bars other than the bus bars of different materials are made of the first conductive material having the first electrical conductivity and the first melting point, and the bus bars of the different material have a reference range And a second electrically conductive material having a second electrical conductivity lower than the first melting point and a second melting point lower than the first melting point.

In the above-described configuration, the bus bars of different materials are disposed at the edges of the battery modules so as to be electrically connected to bus bars of neighboring battery modules.

In addition, in the above-described configuration, the bus bars of different materials may be formed of a material containing any one of gold (Au), silver (Ag), and aluminum (Al) The bus bar may be formed of a material containing copper (Cu).

In the above-described configuration, the bus bars of different materials are electrically connected in a horizontal direction to electrode tabs, which are a pair of external terminals connected to the electrodes of each battery cell, The dimension in the width direction is larger than that in the thickness direction.

According to another aspect of the present invention, there is provided a battery pack for a secondary battery, wherein the plurality of battery modules are connected in series or in parallel.

Advantages of the battery module for a secondary battery and the battery pack according to the present invention are as follows.

First, the battery module for a rechargeable battery according to the present invention physically isolates the line before damage of the battery cell occurs during a short circuit, thereby securing safety against short circuit.

That is, according to the present invention, the bus bars made of different materials are melted and physically separated before the damage of the battery cells, thereby preventing the risk of explosion and ignition of the battery cells as the lines are disconnected .

Next, according to the present invention, when a short circuit occurs, the line is disconnected from the unit battery module before damage occurs in the battery pack unit, so that explosion and ignition due to damage of the battery cell over the entire area of the battery pack can be prevented If you replace the battery module with disconnected line, you can secure the performance of the battery pack.

According to the present invention, there is an effect that the line is blocked before the damage of the battery cell occurs in the short circuit even if there is no separate electrical protection device, thereby securing the safety.

In addition, according to the present invention, it is possible to solve the increase in the resistance of the line due to the installation of the electrical protection device, thereby securing the safety against short circuit and preventing the performance degradation of the battery module and the battery pack.

Further, the battery module for a secondary battery according to the present invention solves the resistance increase of the line, thereby increasing the life cycle of the battery pack, thereby securing the reliability of the battery module and the battery pack.

According to another aspect of the present invention, there is provided an electrical protection device for protecting a battery cell from a short circuit or the like, The line can be blocked by physical separation of the bus bar, and it is possible to escape from the explosion and ignition, so that the safety of the battery pack can be further surely secured.

1 is a plan schematic view of a battery module according to a first embodiment of the present invention;
Fig. 2 is a front view of Fig. 1;
FIG. 3 is a side view schematically showing a side view of FIG. 1 and FIG.
FIG. 4 is a schematic view of a second embodiment of the present invention,

Hereinafter, preferred embodiments of a battery module for a rechargeable battery and a battery pack according to the present invention will be described in detail with reference to the accompanying drawings 1 to 4.

In the present specification, 'bus bars of different materials' do not mean bus bars manufactured by using different kinds of materials, but mean bus bars having different melting points from other bus bars in the battery module It is assumed that it is used.

[Example 1]

1 to 3, a battery module 100 for a rechargeable battery according to the present invention includes a plurality of battery cells 110 and a plurality of bus bars for electrically connecting the battery cells 110 to each other, The bus bar 120a may be made of a different kind of material having a low melting point compared to the other bus bars 120b so that the battery bus 110 may be physically separated from the plurality of bus bars before the battery cell 110 is short- .

That is, at least one bus bar 120a among the plurality of bus bars electrically connecting the battery cells 110 to each other may be made of a different material having a low melting point compared to the other bus bars 120b, The bus bar 120a of different material is melted to block the line before the battery cell is damaged when a short circuit occurs.

Specifically, the bus bar 120b other than the bus bar 120a of different materials is made of the first conductive material having the first electrical conductivity and the first melting point, and the bus bar 120a of the different material is made of the A second electrical conductivity that is within a reference range for electrical conductivity, and a second conductive material having a second melting point lower than the first melting point.

The bus bars 120a may be disposed at the edge of the battery module 100 so as to be electrically connected to bus bars of neighboring battery modules (not shown).

For example, referring to FIG. 1, the bus bar 120a made of different materials is connected to the positive electrode tab (not shown) of the battery cell 110 (i.e., the battery cell at the right edge of the figure) disposed at the edge of the battery module 100 130a and is electrically connected to the negative electrode side of the battery cell 110 disposed at the edge of another neighboring battery module to form a battery pack.

The bus bar 120a made of different material is made of a material containing any one of gold (Au), silver (Ag), aluminum (Al), antimony (Sb), magnesium (Mg) And the bus bars 120b other than the bus bars 120a of different materials are preferably made of copper (Cu), but the materials of the bus bars are not limited to those mentioned above .

The bus bars 120a are electrically connected in a horizontal direction to the electrode tabs 130a, which are a pair of external terminals connected to the electrodes of the battery cells 110 (see FIG. 3) The dimensions of the bus bars 120a of different materials are larger in the width W direction than the thickness T of the battery cells 110 (see FIGS. 1 and 2).

It is preferable that the bus bars 120a of different materials are disposed at the edge of the battery module 100 for convenience of system configuration and maintenance of the battery module 100 and the battery pack.

On the other hand, reference numeral 140 denotes a welding line between the bus bar and the external terminal.

The functions of the battery module and the battery pack of the present invention constructed as described above are as follows.

The battery module 100 for a secondary battery according to the present invention is configured such that a bus bar 120a made of a dissimilar material having a low melting point is melted first before a damage of the battery cell 110 occurs when a short circuit occurs, So that the line is shut off and the safety of the battery pack is secured.

That is, according to the present invention, when a short circuit occurs during a test for safety certification or during actual use, the bus bar 120a made of a different material is melted and physically separated before the battery cell 110 is damaged due to a short- , The risk of explosion and ignition of the battery cell 110 is prevented in advance as the line is disconnected, thereby ensuring the safety of the battery pack.

For example, when the bus bar 120a of the entire bus bar is physically spaced apart from the bus bar 120a by aluminum and the remaining bus bar 120b is made of copper, the melting point of copper (Cu) Since the melting point of Al is 660 ° C, the bus bar 120a made of aluminum is melted and physically separated before damage of the battery cell 110 occurs at the time of short circuit, thereby securing safety of the battery pack.

In other words, since the bus bar 120a of the dissimilar material acting as the line shutoff part at the time of short-circuiting exhibits a value substantially similar to that of copper in terms of electrical conductivity to such an extent as to satisfy the required performance of the battery pack, The battery cell 110 is melted and physically separated before the battery cell 110 is damaged during a short circuit without deteriorating the capacity of the battery pack.

In the meantime, according to the present invention, when a short circuit occurs, disconnection of a line in the battery module 100 is performed by a bus bar 120a made of different material before a cell damage occurs, so that explosion and ignition due to cell damage over the entire area of the battery pack And even if the line is blocked due to a short circuit, only the battery module in which the bus bar is melted is replaced with a new one in the battery pack, so that the performance of the battery pack can be easily secured.

Particularly, according to the present invention, before the damage of the battery cell 110 occurs when a short circuit occurs, the line is shut off due to the physical separation due to melting of the bus bar 120a made of different material, , It is possible to prevent power loss of the battery module and the battery pack because there is no resistance of the line due to the installation of a separate electrical protection device for the short circuit.

In other words, the present invention eliminates a separate electrical protection device such as a fuse, a bimetal, etc., thereby eliminating an increase in resistance of a line due to the installation of a separate protection device. Accordingly, while securing safety against short- It is possible to prevent the performance degradation of the display device.

Since the battery module 100 for a secondary battery according to the present invention does not require any electrical protection device, the resistance of the line can be lowered, thereby increasing the life cycle of the battery pack. And the reliability of the battery pack can be ensured.

In other words, if the protection device is connected to the battery pack to protect the battery cell 110 from a short circuit or the like, the protection device can operate normally The line is blocked before the battery cell 110 is damaged by the physical separation of the bus bar 120a made of different materials so that the danger of explosion and ignition can be solved. It is possible to secure a higher level of safety and reliability as compared with the case of the first embodiment.

[Example 2]

In the battery module 100 of the first embodiment described above, the bus bars 120a and 120b are limited to plate-shaped electrical conductors which are raised above the electrode tabs. However, But it is not limited to a single bus bar.

The bus bars 120a and 120b of the above-described first embodiment are described based on the schematic diagrams of FIGS. 1 to 3. In this embodiment, the bus bar, which is an electrical conductor, is used in a wider sense , Which can be confirmed through the concrete form of FIG.

4, the bus bar provided to electrically connect the battery cells 110 to each other includes an electrode tab 130a connected to each electrode of the battery cell 110, A busbar bottom 120-2 of a '∩' -shaped section to be joined, and an upper bus bar 120-1 (busbar top) joined to the lower bus bar 120-2. A portion of the electrode tab 130a, the lower bus bar 120-2, and the upper bus bar 120-1, which must be physically separated before damage of the battery cell, is lowered to a low melting point (Low Melting Point).

Therefore, in the battery module of this embodiment according to the bus bar structure of FIG. 4, a bus bar, which should be physically separated from the plurality of bus bars before the battery cell is short-circuited, is connected to the low- ), The following various combinations are possible.

That is, in the event of a short circuit, the one bus bar is first melted and physically separated before the battery cell is damaged. In this case, one bus bar may refer to only the upper bus bar 120-1, ), And may mean only the electrode tab 130a.

One bus bar to be physically separated before the battery cell is damaged in the event of a short circuit means a combination of the electrode tab 130a and the lower bus bar 120-2 or a combination of the lower bus bar 120-2 and the upper bus bar 120-2, May mean a combination of the bus bars 120-1 or a combination of the three elements of the electrode tab 130a, the lower bus bar 120-2 and the upper bus bar 120-1.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. To those who have.

For example, in the detailed description, the bus bar 120a coupled to the anode-side electrode tab 130a of the battery cell 110 (the battery cell at the right edge of the figure) disposed at the edge of the battery module 100 is made of a different material It is needless to say that the bus bar coupled to the negative electrode tab 130b of the battery cell 110 disposed at the left edge of the battery module 100 may be made of different materials.

Therefore, it should be understood that the above-described embodiments are to be considered as illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description and can be modified and modified within the scope of the appended claims and the equivalents thereof .

Unlike conventional primary batteries, which can not be charged, secondary batteries that can be charged and discharged are developed in the advanced fields of digital cameras, cellular phones, laptop computers, power tools, electric bicycles, especially electric vehicles, hybrid vehicles, Active research and development are in progress, so that the battery module and the battery pack for a secondary battery of the present invention are very industrially applicable.

100: Battery module 110: Battery cell
120a: Bus bars of different materials
120b: Bus bars other than bus bars of different materials
120-1: Upper bus bar 120-2: Lower bus bar
130a, 130b: electrode tab 140: weld line

Claims (8)

A battery module comprising: a plurality of battery cells; and a plurality of bus bars for electrically connecting the battery cells to each other;
A bus bar that is to be physically separated from the plurality of bus bars before the battery cell is damaged may be formed of a different material having a low melting point compared to the other bus bars,
Wherein the one bus bar is melted and physically separated before the battery cell is damaged when a short circuit occurs. The method according to claim 1,
Wherein the bus bars other than the bus bars of different materials are made of a first conductive material having a first electrical conductivity and a first melting point,
Wherein the bus bars of different materials are made of a second conductive material having a second electrical conductivity within a reference range for the first electrical conductivity and a second melting point lower than the first melting point. The method according to claim 1,
And the bus bars of different materials are disposed at the edge of the battery module so as to be electrically connected to bus bars of neighboring battery modules. The method according to claim 1,
The bus bars of different materials may include any one of Au, Ag, Al, Sb, Mg, and Zn.
Wherein the bus bars other than the bus bars of different materials can be formed of copper (Cu). The method according to claim 1,
The bus bars of different materials are electrically connected in a horizontal direction to a pair of external terminals connected to the electrodes of each battery cell,
Wherein the dimensions of the bus bars of the different materials are larger than those of the battery cells in the width direction. The method according to claim 1,
Wherein,
An electrode tab connected to each electrode of the cell, a 'busbar bottom' having a cross section of '∩' shape joined on the electrode tab, and an upper bus bar bonded on the lower bus bar,
The bus bar, which must be physically separated from the bus bar before the battery cell is damaged,
Wherein at least one of the electrode tab, the lower bus bar, and the upper bus bar is made of a different material having a low melting point so that the at least one of the electrode tab, the lower bus bar, and the upper bus bar is physically spaced apart. The method according to claim 6,
Wherein,
A combination of electrode tabs and a lower bus bar, a combination of a lower bus bar and an upper bus bar, or a combination of an electrode tab, a lower bus bar and an upper bus bar, may be made of a low melting point material And the second battery module is connected to the second battery module. A battery pack for a secondary battery, wherein a plurality of battery modules according to any one of claims 1 to 7 are connected in series or in parallel.

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