This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0161298 on December 13, 2018, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
The present invention relates to a battery module, and more particularly, to a battery module including a bus bar having improved safety.
background
[4]
Since secondary batteries are easy to apply according to product groups and have electrical characteristics such as high energy density, they are universally applied to electric vehicles or hybrid vehicles driven by electric driving sources, power storage devices, etc. as well as portable devices. These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency in that not only the primary advantage of being able to dramatically reduce the use of fossil fuels, but also the fact that no by-products are generated from the use of energy.
[5]
The battery pack applied to the electric vehicle has a structure in which a plurality of cell assemblies including a plurality of unit cells are connected in series to obtain high output. In addition, the unit cell can be repeatedly charged and discharged by an electrochemical reaction between components, including positive and negative current collectors, separators, active materials, electrolytes, and the like.
[6]
On the other hand, in recent years, as the need for a large-capacity structure, including its use as an energy storage source, increases, the demand for a battery pack having a multi-module structure in which a plurality of secondary batteries are connected in series and/or in parallel is increasing. .
[7]
When a battery pack is configured by connecting a plurality of battery cells in series/parallel, a battery module including at least one battery cell is first configured, and other components are added using the at least one battery module to configure the battery pack. How to do it is common The number of battery modules included in the battery pack or the number of battery cells included in the battery module may be variously set according to a required output voltage or charge/discharge capacity. The battery module set in this way is configured to include a plurality of battery cells stacked together and a bus bar electrically connecting electrode leads of the plurality of battery cells.
[8]
In order to secure safety in such a mid-to-large battery module, when the pressure inside the battery cell rises, it is designed to melt the lead inside the cell to cut off the current. There is a problem with transformation. For this reason, even in mid- to large-sized battery modules, when the temperature inside the cell rises, there is a need for a means for stably securing safety by blocking the current.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
The problem to be solved by the present invention is that in the battery module, safety can be secured by blocking current in abnormal situations such as thermal runaway due to temperature rise, and at the same time, the resistance is not high under normal conditions, so that the existing performance can be maintained the same. An object of the present invention is to provide a battery module including a bus bar.
[10]
However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems and may be variously expanded within the scope of the technical idea included in the present invention.
means of solving the problem
[11]
A battery module according to an embodiment of the present invention includes a plurality of battery cells and a bus bar electrically connecting the plurality of battery cells, wherein the bus bar is inserted into a bus bar body and a part of the bus bar body and a safety part surrounded by the busbar body, wherein the safety part includes a volume expansion resin, a conductive material, and an adhesive.
[12]
The safety part may have the same thickness as the bus bar body.
[13]
The volume expansion resin may include a material that generates gas in an environment of a predetermined temperature or higher.
[14]
The volume expansion resin may include melamine cyanurate.
[15]
The safety part may be formed by mixing the volume expansion resin, the conductive material, and the adhesive.
[16]
In the environment above the predetermined temperature, the resistance of the safety part may be increased by the generation of gas from the volume expansion resin, and the current may be cut off.
[17]
In an environment below the predetermined temperature, the safety part may have conductivity due to the conductive material.
[18]
The conductive material may be a metal powder or a carbon powder.
[19]
The predetermined temperature may be 110 °C to 120 °C.
[20]
The bus bar includes a slit formed on the bus bar body into which leads extended from the plurality of battery cells are inserted, and a terminal connection part extending from one end of the bus bar body and having a bent shape, The safety part may be positioned between the slit and the terminal connection part.
[21]
The safety part may have a shape in which a plurality of stripes are aggregated.
[22]
A battery pack according to another embodiment of the present invention may include the at least one battery module and a pack case for packaging the at least one battery module.
[23]
A device according to another embodiment of the present invention may include the above-described at least one battery pack.
Effects of the Invention
[24]
According to the embodiment, in the battery module, it is possible to secure safety by blocking current in abnormal situations such as thermal runaway due to temperature rise, and at the same time, using a bus bar that can maintain the same performance as the existing performance because the resistance is not high in a normal situation. It is possible to improve the safety of the battery module.
Brief description of the drawing
[25]
1 is an enlarged view illustrating a part of a battery module according to an embodiment of the present invention.
[26]
FIG. 2 is a front view illustrating a bus bar of the battery module shown in FIG. 1 .
[27]
FIG. 3 is a view showing a cross-section taken along III-III′ of the bus bar shown in FIG. 2 .
[28]
4 is a front view showing a bus bar according to another embodiment of the present invention.
Modes for carrying out the invention
[29]
Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.
[30]
In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.
[31]
In addition, throughout the specification, when "on a plane", it means when the target part is viewed from above, and when "in cross-section", it means when viewed from the side of a cross-section obtained by cutting the target part vertically.
[32]
1 is an enlarged view illustrating a part of a battery module according to an embodiment of the present invention.
[33]
Referring to FIG. 1 , a battery module 10 according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells 100 are stacked and a battery cell stack electrically connecting the plurality of battery cells 100 . and a bus bar 200 .
[34]
The individual battery cells 100 constituting the battery cell stack may be, for example, pouch-type battery cells, in which an electrode assembly is accommodated in a pouch case, and may be electrically connected to each other. The electrode assembly may include a positive electrode plate, a negative electrode plate, and a separator, and since an electrode assembly having a known structure may be adopted, a detailed description thereof will be omitted herein.
[35]
The pair of electrode leads 110 connected to the electrode assembly may be drawn out of the pouch case, for example, may be drawn out in the same direction or opposite directions. In the drawings of the present invention, only the pouch-type battery cell 100 having a shape in which a pair of electrode leads 110 are drawn out in opposite directions is illustrated for convenience of drawing, but the battery applied to the battery module according to the present invention The cell 100 is not necessarily limited thereto, and a case in which a pair of electrode leads 110 are drawn out in the same direction is also possible.
[36]
The battery cells 100 are stacked so that electrode leads 11 having the same polarity are positioned in the same direction. This is because, when the electrode leads 110 are electrically connected using the bus bar 200 , the electrode leads 110 having the same polarity must be connected to each other. As such, the electrode leads 110 having the same polarity are electrically connected to each other, so that each of the battery cells 100 is connected in parallel.
[37]
As the electrode lead 110 , for example, a thin metal plate made of aluminum (Al) coated with nickel (Ni) may be used, and welding for bonding the electrode lead 110 to the bus bar 200 may be used. A tin (Sn) coating may be applied to the surface of the electrode lead 110 in order to facilitate the operation.
[38]
The bus bar 200 is for electrically connecting the electrode leads 110 provided in each battery cell 100 , and may include a slit 202 into which the electrode leads 110 may be inserted. Electrical connection can be achieved by bending the electrode lead 110 inserted into the slit 202 so that the electrode lead 110 and the bus bar 200 are in surface contact, and then connecting by welding or the like.
[39]
The bus bar 200 includes a first bus bar 210 used to connect the battery cells 100 in the battery module 10 in parallel, and a second bus bar 210 used to electrically connect the battery module 10 to an external terminal. A bus bar 220 may be included. The first bus bar 210 may include a flat bus bar body 211 and a slit 202 formed therein as shown in FIG. 1 , but the structure is not limited thereto. That is, a form including a plurality of slits in one body or an additional hole or protrusion for coupling with other components other than the electrode lead may be included, and may be appropriately deformed as necessary. As shown in FIG. 1 , the second bus bar 220 includes a bus bar body 221 including a slit 202 , and extending from one end of the bus bar body 221 to be opposite to the battery module 100 . It may include a terminal connection part 222 formed by bending to be substantially perpendicular to the bus bar body 221 in the direction. The terminal connection part 222 may include one or more holes 223 that may be connected to an external terminal.
[40]
The bus bar 200 may be coupled to a bus wave frame (not shown) and the like and coupled to the electrode lead 110 by coupling the module frame (not shown) for accommodating the battery cell stack and the bus bar frame. However, it is not particularly limited.
[41]
FIG. 2 is a front view showing a bus bar of the battery module shown in FIG. 1 , and FIG. 3 is a view showing a cross-section taken along line III-III' of the bus bar shown in FIG. 2 .
[42]
1, 2 and 3 , the bus bar 200 (in this embodiment, the second bus bar 220 will be described as an example) is inserted into a part of the bus bar body 221 and the bus bar body ( 221 includes a safety portion 230 surrounded by.
[43]
The safety part 230 includes a volume expansion resin, a conductive material, and an adhesive. That is, the safety part 230 may be formed by filling the space (hole) formed in the bus bar body 221 with a paste-like material in which the volume expansion resin, the conductive material, and the adhesive are mixed, and then curing it. Therefore, the safety part 230 may have the same thickness as the bus bar body 221 .
[44]
The volume expansion resin included in the safety unit 230 includes a material that generates gas in an environment of a predetermined temperature or more, specifically, in an environment of 110° C. to 120° C. or more. That is, the volume expansion resin is a material capable of generating gas by thermal decomposition at a temperature of 110° C. to 120° C. or higher. Examples of the volume expansion resin include melamine cyanurate and the like.
[45]
The conductive material included in the safety part 230 may be conductive powder, for example, metal powder or carbon powder may be used. Examples of the metal powder include silver, aluminum, gold, lead, and the like, but is not particularly limited. The safety part 230 may be formed by mixing such conductive powder with an adhesive, or by mixing a commercially available metal paste with the volume expansion resin and an adhesive to be described later. Since the safety unit 230 includes such a conductive material, an increase in resistance of the bus bar 200 by the safety unit 230 occurs when the battery module operates normally (that is, when an abnormal temperature rise does not occur). It allows the current to flow smoothly without any problems.
[46]
The adhesive included in the safety part 230 is not particularly limited as long as it is a resin that can be mixed with a volume expansion resin and a conductive material to form a paste and be cured, for example, an epoxy resin or the like may be used .
[47]
The safety part 230 may be formed by mixing a volume expansion resin, a conductive material, and an adhesive to form a paste, then filling the space (hole) formed in the bus bar body 221 and curing the mixture. The volume expansion resin included in the safety unit 230 is thermally decomposed to generate gas when the temperature in the battery module is abnormally increased (thermal runaway) to 110° C. to 120° C. or higher. For example, when melamine isocyanurate is used as the volume expansion resin, nitrogen gas is generated by thermal decomposition. When gas is generated in this way, the safety unit 230 expands to increase resistance. That is, since the safety part 230 acts as a resistance layer and the resistance increases between both sides around the safety part 230 , no current flows or the amount of current flowing is reduced. Therefore, when a sudden temperature rise occurs due to abnormal operation, it is possible to efficiently cut off the current to improve the safety of the battery module.
[48]
In addition, as shown in FIG. 3 , when the safety part 230 is formed by mixing the volume expansion resin, the conductive material, and the adhesive, the safety part 230 may be formed to the same thickness as the bus bar body 221 , and thus Even if the safety part 230 is added, the structure of the conventional bus bar 200 does not change, so the configuration of the safety part 230 can be easily adopted without a design change.
[49]
In FIG. 2 , the safety part 230 included in the second bus bar 220 has been described as an example, but the safety part 230 may be included in the first bus bar 210 and may be used for electrical connection of other components. It may also be employed for safety, and is not particularly limited. However, when the safety part 230 is located near the terminal connection part 222 connected to the external terminal, the current flow with the outside is blocked, so that the effect of cutting off the current more quickly and effectively for the entire battery module 10 is achieved. There are advantages to being able to do this. That is, as shown in FIG. 2, the safety part 230 may be located between the slit 202 and the terminal connection part 222, and thereby the battery module ( 10) It is possible to quickly cut off the electrical connection from the outside for the whole.
[50]
4 is a front view showing a bus bar according to another embodiment of the present invention.
[51]
Referring to FIG. 4 , the bus bar 200 according to another embodiment of the present invention may include a safety part 231 formed in a form in which a plurality of stripes are aggregated. Configurations other than the shape of the safety part 231 are the same as those of the previous embodiment, and a description thereof will be omitted herein.
[52]
The safety part 231 included in the bus bar 200 of this embodiment has a form in which a plurality of stripes are aggregated, and after forming a plurality of pattern-shaped holes in the bus bar body 221 , the volume expansion resin and conductivity described above are It can be formed by filling with a paste obtained by mixing a substance and an adhesive and curing it. According to this, since each region filled by the paste is narrow, even if the viscosity of the paste is slightly thin, the safety portion 231 can be formed without being affected by this, and workability is improved.
[53]
In addition, even with this shape, since thermal decomposition by the volume expansion resin sufficiently occurs in the region where the safety part 231 is formed when the temperature is abnormally increased, the current blocking effect by the safety part 231 can be achieved in the same way.
[54]
Meanwhile, one or more battery modules according to an embodiment of the present invention may be packaged in a pack case to form a battery pack.
[55]
The above-described battery module and battery pack including the same may be applied to various devices. Such a device may be applied to transportation means such as an electric bicycle, an electric vehicle, and a hybrid vehicle, but the present invention is not limited thereto and is applicable to various devices that can use a battery module and a battery pack including the same, and this It belongs to the scope of the invention.
[56]
Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the
[57]
[Explanation of code]
[58]
10: battery module 100: battery cell
[59]
110: electrode lead 200: bus bar
[60]
210: first bus bar 220: second bus bar
[61]
230, 231: safety part 202: slit
[62]
211, 221: bus bar body 222: terminal connection part
[63]
223: Hall
Claims
[Claim 1]
a plurality of battery cells, and a bus bar electrically connecting the plurality of battery cells, wherein the bus bar includes a bus bar body and a safety part inserted into a part of the bus bar body and surrounded by the bus bar body, , The safety part is a battery module comprising a volume expansion resin, a conductive material and an adhesive.
[Claim 2]
The battery module of claim 1 , wherein the safety part has the same thickness as the bus bar body.
[Claim 3]
The battery module of claim 1 , wherein the volume expansion resin includes a material that generates gas in an environment of a predetermined temperature or higher.
[Claim 4]
The battery module of claim 1 , wherein the volume expansion resin comprises melamine cyanurate.
[Claim 5]
The battery module of claim 1 , wherein the safety part is formed by mixing the volume expansion resin, the conductive material, and the adhesive.
[Claim 6]
[4] The battery module of claim 3, wherein the resistance of the safety unit is increased by the generation of gas from the volume expansion resin in an environment above the predetermined temperature to cut off the current.
[Claim 7]
The battery module of claim 3 , wherein the safety part has conductivity by the conductive material in an environment below the predetermined temperature.
[Claim 8]
The battery module of claim 7 , wherein the conductive material is a metal powder or a carbon powder.
[Claim 9]
The battery module of claim 3, wherein the predetermined temperature is 110°C to 120°C.
[Claim 10]
The terminal connector of claim 1 , wherein the bus bar is formed on the bus bar body and has a slit into which leads extending from the plurality of battery cells are inserted, and a terminal connection part extending from one end of the bus bar body and having a bent shape. Including, wherein the safety part is located between the slit and the terminal connection part.
[Claim 11]
The battery module of claim 1 , wherein the safety part has a shape in which a plurality of stripes are aggregated.
[Claim 12]
A battery pack comprising at least one battery module according to any one of claims 1 to 11, and a pack case for packaging the at least one battery module.
[Claim 13]
A device comprising at least one battery pack according to claim 12 .