The present invention relates to a battery module having a structure that breaks a connector using a venting gas, and more specifically, the pressure of the gas discharged to the outside by breaking the pouch case due to an increase in the internal pressure of the battery cell during the charging and discharging process. It relates to a battery module having a structure for breaking the connector using.
[2]
This application is a priority claim for Korean Patent Application No. 10-2017-0115358 filed on September 08, 2017, and all contents disclosed in the specification and drawings of the application are incorporated in this application by citation.
Background
[3]
As the use of portable electric products such as video cameras, portable telephones, and portable PCs is activated, the importance of secondary batteries mainly used as driving power is increasing.
[4]
Unlike primary batteries that cannot be charged, secondary batteries that can be charged and discharged are actively developed through the development of high-tech fields such as digital cameras, cellular phones, laptop computers, power tools, electric bicycles, electric vehicles, hybrid vehicles, and large-capacity power storage devices. Research is ongoing.
[5]
In particular, lithium secondary batteries have high energy density per unit weight and can be rapidly charged compared to other secondary batteries such as lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. Is going on.
[6]
Lithium secondary batteries have a working voltage of 3.6V or higher and are used as power sources for portable electronic devices, or by connecting multiple batteries in series or in parallel, high-power electric vehicles, hybrid vehicles, power tools, electric bicycles, power storage devices, UPS, etc. Is used.
[7]
Lithium secondary batteries have been used at a rapid rate because the operating voltage is three times higher than that of nickel-cadmium batteries or nickel-metal hydride batteries, and the energy density per unit weight is excellent.
[8]
Lithium secondary batteries may be classified into lithium ion batteries using a liquid electrolyte and lithium ion polymer batteries using a polymer solid electrolyte according to the type of electrolyte. Further, the lithium ion polymer battery may be divided into a fully solid lithium ion polymer battery containing no electrolyte solution and a lithium ion polymer battery using a gel polymer electrolyte containing electrolyte, depending on the type of the polymer solid electrolyte.
[9]
In the case of a lithium ion battery using a liquid electrolyte, a cylindrical or square metal can is used as a container and sealed in a sealed manner. Since the can-type secondary battery using such a metal can as a container has a fixed shape, there is a disadvantage that constrains the design of an electric product that uses it as a power source, and it is difficult to reduce the volume. Therefore, a pouch type secondary battery that is used by sealing the electrode assembly and electrolyte in a pouch packaging made of a film has been developed and used.
[10]
However, it is one of the important tasks to ensure safety of lithium secondary batteries because of the risk of explosion when overheated. Overheating of the lithium secondary battery is caused by various reasons, and one of them is a case in which an overcurrent exceeding a limit flows through the lithium secondary battery. When the overcurrent flows, the lithium secondary battery generates heat by Joule heat, so the battery's internal temperature rises rapidly. In addition, the rapid rise in temperature causes a decomposition reaction of the electrolyte, causing a thermal runaway, which eventually leads to an explosion of the battery. The overcurrent is the rush current due to the breakdown of the insulation between the positive electrode and the negative electrode due to the contraction of the separator interposed between the positive electrode and the negative electrode when a pointed metal object penetrates the lithium secondary battery or the external charging circuit or load is abnormal. Is generated in the case of being applied to a battery.
[11]
Therefore, a lithium secondary battery is used in combination with a protection circuit to protect the battery from abnormal conditions such as occurrence of overcurrent, and the protection circuit is a fuse element that irreversibly disconnects a line through which charging or discharging current flows when an overcurrent occurs. It is common to include.
[12]
1 is a circuit diagram for explaining an arrangement structure and an operation mechanism of a fuse element in a configuration of a protection circuit coupled with a battery pack including a lithium secondary battery.
[13]
As shown in the figure, the protection circuit operates a fuse element 1 to protect the battery pack when an overcurrent occurs, a sense resistor 2 for overcurrent sensing, and an overcurrent occurrence to operate the fuse element 1 when an overcurrent occurs It includes a microcontroller 3 and a switch 4 for switching the inflow of operating current to the fuse element 1.
[14]
The fuse element 1 is installed on the main line connected to the outermost terminal of the battery pack. The main line is a wiring through which charging or discharging current flows. In the drawing, the fuse element 1 is illustrated as being installed on a high potential line (Pack+).
[15]
The fuse element 1 is a three-terminal element component, and two terminals are connected to a main line through which charging or discharging current flows, and one terminal is connected to the switch 4. In addition, a fuse 1a connected to the main line in series and fused at a specific temperature, and a resistor 1b for applying heat to the fuse 1a are included.
[16]
The microcontroller 3 periodically detects the voltage across the sense resistor 2 to monitor whether an overcurrent has occurred, and if it is determined that an overcurrent has occurred, turn on the switch 4. Then, the current flowing through the main line is bypassed toward the fuse element 1 and applied to the resistor 1b. Accordingly, the Joule heat generated in the resistor 1b is conducted to the fuse 1a to raise the temperature of the fuse 1a, and when the temperature of the fuse 1a rises to the melting temperature, the fuse 1a is melted, so that the main The line is irreversibly disconnected. If the main line is disconnected, the overcurrent will no longer flow, so the problem resulting from the overcurrent can be solved.
[17]
However, the prior art as described above has various problems. That is, when a failure occurs in the microcontroller 3, the switch 4 is not turned on even in a situation where an overcurrent occurs. In this case, since the current does not flow into the resistor 1b of the fuse element 1, there is a problem that the fuse element 1 does not operate. In addition, a space for the placement of the fuse element 1 in the protection circuit is required separately, and a program algorithm for controlling the operation of the fuse element 1 must be loaded in the microcontroller 3. Therefore, there is a disadvantage that the space efficiency of the protection circuit is reduced and the load of the microcontroller 3 is increased.
Detailed description of the invention
Technical challenges
[18]
The present invention was devised in consideration of the above-described problems, and when the internal pressure of the battery cell increases by a certain level or more due to an abnormal situation such as overcharging or short circuit, the flow of current is rapidly blocked by using the exhaust pressure of the venting gas. The objective is to secure the safety of using the secondary battery.
[19]
However, the technical problem to be solved by the present invention is not limited to the above-described problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
Task resolution
[20]
A battery module according to an embodiment of the present invention for solving the above-described technical problem includes: a cell stack comprising first and second battery cells stacked facing each other and having electrode leads; A connector connecting between the electrode leads of each of the pair of battery cells; And is provided on at least one side of the cell stack, a pair of lead slit to which the electrode lead is drawn and formed in a position corresponding to the connector is a passage through which the venting gas discharged when venting the battery cell is injected Includes; support frame having a spray slit provided.
[21]
The end of the electrode lead exposed to the outside of the lead slit may be bent and supported by the support frame.
[22]
The injection slit may be formed in a position corresponding to a space formed between each of the terrace portions of the first battery cell and the second battery cell.
[23]
The joining portion between the support frame and the cell stack may have a sealed structure so that the venting gas can be discharged only through the injection slit.
[24]
A sealing member may be interposed in an empty space formed between the inner surface of the lead slit and the electrode lead.
[25]
The battery cell includes: an electrode assembly having an electrode tab; An electrode lead attached to the electrode tab; A pouch case accommodating the electrode assembly so that the electrode lead is drawn out; And a sealing tape interposed between the electrode lead and the inner surface of the pouch case as having at least one venting pattern portion.
[26]
The venting pattern portion may correspond to a notch formed at a predetermined depth along the extending direction of the electrode lead.
[27]
The venting pattern portion may have a shape in which the width gradually narrows along the extending direction of the electrode lead.
[28]
The venting pattern portion may have a wedge shape.
[29]
The venting pattern portions may be formed spaced apart from each other along the longitudinal direction of the sealing tape.
[30]
The pouch case has a sealing area formed on an edge, and at least a portion of the venting pattern portion may be located in the sealing area.
[31]
The venting pattern portion may be formed on both surfaces of the electrode lead.
Effects of the Invention
[32]
According to an aspect of the present invention, when the internal pressure of the battery cell is abnormally high due to an abnormal situation such as overcharging or short circuit, the secondary battery is ignited/exploded by rapidly blocking the flow of current by using the discharge pressure of the venting gas. It can be prevented from occurring, thereby securing safety in the use of the secondary battery.
Brief description of the drawing
[33]
The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of ​​the present invention together with the detailed description of the invention described below, and thus the present invention is described in such drawings. It should not be interpreted as being limited to.
[34]
1 is a circuit diagram for explaining an arrangement structure and an operation mechanism of a fuse element in a configuration of a protection circuit coupled with a battery module.
[35]
2 is a perspective view showing a battery module according to an embodiment of the present invention.
[36]
3 is a plan view illustrating a battery cell applied to a battery module according to an embodiment of the present invention.
[37]
4 and 5 are cross-sectional views taken along the line XX' of FIG. 2.
[38]
FIG. 6 is an enlarged view of region M shown in FIG. 3.
[39]
7 and 8 are cross-sectional views taken along the line YY′ in FIG. 6.
[40]
9 and 10 are views showing a battery cell having a venting pattern portion of a different form from that of FIG. 7.
Mode for carrying out the invention
[41]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to ordinary or lexical meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention. Therefore, the embodiments shown in the embodiments and the drawings shown in the present specification are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, and thus can replace them at the time of application. It should be understood that there may be equivalents and variations.
[42]
[43]
First, with reference to FIGS. 2 to 5, the structure of the battery module according to an embodiment of the present invention will be described.
[44]
2 is a perspective view showing a battery module according to an embodiment of the present invention, Figure 3 is a plan view showing a battery cell applied to a battery module according to an embodiment of the present invention. 4 and 5 are cross-sectional views taken along the line XX' of FIG. 2.
[45]
2, the battery module according to an embodiment of the present invention, a cell stack comprising a pair of battery cells 10, a connector 20 for electrically connecting a pair of battery cells 10 And a support frame 30 disposed on at least one side of the cell stack.
[46]
The cell stack includes a first battery cell 10 and a second battery cell 10 stacked to face each other. Each of the battery cells 10 constituting the cell stack may be substantially the same battery cell.
[47]
Referring to FIG. 3, the pair of battery cells 10 may be, for example, pouch-type battery cells. The battery cell 10 may be implemented in a form including an electrode assembly 11, a pouch case 12, an electrode lead 15 and a sealant 16.
[48]
Although not specifically shown in the drawings, the electrode assembly has a form in which a positive electrode plate, a separator, and a negative electrode plate are sequentially stacked at least once or more, and it is preferable that a separator is positioned on the outermost side to secure insulation. The electrode assembly 11 may have various structures, such as a wound type, a stack type, or a stack/folding type, according to an embodiment.
[49]
The positive electrode plate has a form in which a positive electrode active material is coated on at least one surface of a positive electrode current collector plate made of a conductive plate, and similarly, the negative electrode plate has a negative electrode active material coated on at least one surface of a negative electrode current collector plate made of a conductive plate. Have
[50]
The positive electrode plate and the negative electrode plate have a positive electrode active material and a non-coated region where the negative electrode active material is not coated, and the non-coated region functions as an electrode tab 11a coupled to the electrode lead 15.
[51]
The separator may be positioned between the positive electrode plate and the negative electrode plate to electrically insulate the positive electrode plate and negative electrode plate, and may have a porous membrane shape to allow lithium ions to move between the positive electrode plate and the negative electrode plate. The separator may be made of, for example, a porous film using polyethylene (PE) or polypropylene (PP) or a composite film thereof.
[52]
The pouch case 12 may be a pouch case made of an exterior material having a multi-layered film form including a metal layer and a resin layer surrounding it, and the pouch case 12 may be composed of an upper case and a lower case. .
[53]
As such, when the pouch case 12 is composed of an upper case and a lower case, the lower case includes a receiving portion 13 protruding convexly to accommodate the electrode assembly. In addition, the upper case may have a receiving portion 13 protruding convexly, or may have a flat shape in which such a receiving portion 13 is not formed.
[54]
That is, the battery cell 10 may be a two-sided protruding battery cell in which both sides protrude, or alternatively, may be a one-sided protruding battery cell in which only one side protrudes. In the drawings of the present invention, for convenience of illustration, only the case where the battery cell 10 is a two-sided protruding battery cell is shown, but the present invention is not limited thereto.
[55]
On the other hand, in the case where the battery cells are double-sided protruding battery cells, each of the upper case and the lower case may include a sealing portion 14 corresponding to an outer circumferential area of ​​the receiving portion 13. In addition, in the case where the battery cell 10 is a one-sided protruding battery cell, the lower case has a sealing portion 14 corresponding to the outer circumferential area of ​​the receiving portion 13, and the upper case is sealed of the lower case. A sealing portion 14 formed in a region in contact with the portion 14 may be provided.
[56]
The pouch case 12 is sealed by accommodating the electrode assembly in the accommodating portion 13 and sealing the respective sealing portions 14 of the upper case and the lower case by thermal welding. As such, the sealing parts 14 of the upper case and the lower case may be made of a resin material having heat fusion properties, so that they can be joined by heat fusion in a state of mutual contact.
[57]
The electrode lead 15 is connected to the electrode tab 11a of the electrode assembly and is drawn to the outside of the pouch case 12 to serve as a medium that electrically connects the electrode assembly and the external components, and is provided on the positive electrode plate. It includes a positive electrode lead connected and a negative electrode lead connected to the negative electrode plate. More specifically, the positive electrode lead is connected to the positive electrode uncoated portion provided on the positive electrode plate, and the negative electrode lead is connected to the negative electrode uncoated portion provided on the negative electrode plate.
[58]
The positive electrode lead and the negative electrode lead provided in one battery cell 10 may be drawn out in the same direction or opposite directions to each other. In the drawings of the present invention, the positive electrode lead and the negative electrode lead are drawn out in opposite directions to each other. Only (10) is shown.
[59]
On the other hand, in describing the present invention, the sealing portion 14 located in the direction in which the electrode lead 15 is drawn out of the sealing portion 14 will be referred to as a terrace portion.
[60]
The sealant 16 is the inner surface of the sealing portion 14 in order to prevent a decrease in sealing force between the electrode lead 15 drawn out of the pouch case 12 and the inner surface of the sealing portion 14 And an electrode lead 15.
[61]
Since the battery cell 10 is sealed by heat-sealing the upper case and the lower case as described above, when gas is generated inside and the internal pressure rises above a certain level, the sealing part 14 is heat-sealed. The site may break and venting may occur.
[62]
In the battery cell 10, in particular, gas is collected in an internal gas collecting space S formed between the sealing portion 14 and the electrode assembly 11 positioned in the direction in which the electrode lead 15 is drawn out, thereby When the internal pressure becomes higher than a certain level, venting occurs through the sealing portion 14 positioned in the direction in which the electrode lead 15 is pulled out (that is, venting occurs in the direction of the arrow in FIG. 3 ).
[63]
The battery module according to an embodiment of the present invention, in consideration of such a venting direction, as will be described later, by placing the support frame 30 on at least one side of the cell stack, the battery cell using the injection pressure of the venting gas It is designed to block the electrical connection between (10).
[64]
[65]
The connector 20 is a component applied to electrically connect mutually adjacent battery cells 10 to each other, and quickly and reliably breaks when venting occurs in the battery cell 10 while minimizing electrical resistance. In order to be able to be, for example, it can be implemented in the form of multiple metal wires.
[66]
In this case, the individual metal wires may be connected by welding or the like with each electrode lead 15 of each pair of adjacent battery cells 10, and the metal wire and electrode lead ( 15) The welding portion between the livers is broken, so that the electrical connection between the neighboring battery cells 10 is cut off.
[67]
[68]
The support frame 30 is disposed on at least one side of the cell stack, and includes a pair of lead slits 31 through which the electrode leads 15 pass, and also provides a passage through which venting gas is injected. It is provided with a spray slit (32). The support frame 30 may be made of a resin material having insulating properties.
[69]
The pair of lead slits 31 and the lower surface of the support frame 30 so that the electrode leads 15 of the first battery cell 10 and the second battery cell 10 are passed through and exposed to the outside, respectively. It is formed through between the upper surfaces. The electrode lead 15 extends upward and is exposed to the outside of the lead slit 31, and the end of the exposed electrode lead 15 is bent and supported by being seated on the upper surface of the support frame 30.
[70]
The injection slit 32 is formed at a position corresponding to the connector 20, and functions as a passage through which venting gas discharged when the battery cell 10 is vented can be injected toward the connector 20. The injection slit 32 is formed at a position corresponding to the space G formed between each of the terrace portions of the first battery cell 10 and the second battery cell 10.
[71]
The injection slit 32 is formed between a pair of lead slits 31 and, like the lead slits 31, is formed to penetrate between the lower surface and the upper surface of the support frame 30, the lower portion of the injection slit 32a ) Has a wider width than the upper portion 32b of the injection slit.
[72]
The lower portion 32a of the injection slit corresponds to a space in which the venting gas discharged from the battery cell 10 preferentially collects, and the upper portion 32b of the injection slit has a narrower width than the lower portion 32a of the injection slit. By doing so, the venting gas collected in the lower portion 32a of the injection slit can be injected upward with strong pressure.
[73]
As described above, the battery module according to an embodiment of the present invention breaks a connection portion between the connector 20 and the electrode lead 15 by using a venting gas injected through the injection slit 32, and the battery module 10 is adjacent to each other. The electrical connection can be cut off.
[74]
In order to increase the injection pressure of the venting gas, it is preferable that the sealing is made to prevent the venting gas from escaping through a space other than the injection slit 32. Accordingly, the battery module according to an embodiment of the present invention may have a structure in which the bonding portion between the support frame 30 and the cell stack is sealed.
[75]
In addition, since the venting gas may leak through an empty space formed between the inner surface of the lead slit 31 and the electrode lead 15, the inner surface of the lead slit 31 and the electrode lead 15 may be prevented. ) The sealing member may be interposed in the empty space formed between.
[76]
[77]
Next, a battery module according to another embodiment of the present invention will be described with reference to FIGS. 6 to 10.
[78]
FIG. 6 is an enlarged view of region M shown in FIG. 3, and FIGS. 7 and 8 are cross-sectional views taken along the line YY′ of FIG. 6. In addition, FIGS. 9 and 10 are views showing a battery cell provided with a venting pattern portion of a different form from FIG. 7.
[79]
The battery module according to another embodiment of the present invention has only some differences in the structure of the sealant 16 provided in the battery cell 10 in comparison with the battery module according to the embodiment of the present invention described above. The components are substantially the same.
[80]
Therefore, in describing the battery module according to another embodiment of the present invention, the structure of the sealant 16 of the battery cell 10 will be mainly described, and repeated descriptions of the overlapping matters from the previous embodiment will be given. It will be omitted.
[81]
In the battery cell 10 applied to the present invention, the sealing portion 14 is not formed only in the direction in which the electrode lead 15 is pulled out, but the sealing portion 14 is formed around the receiving portion 13 as a whole. Therefore, there is a possibility that venting occurs even outside the support frame 30 when the internal pressure increases.
[82]
6 and 7, the battery module according to an embodiment of the present invention, as described above, to prevent the venting from occurring on the outside of the support frame 30, the venting pattern portion ( 16a).
[83]
The venting pattern portion 16a corresponds to a notch formed at a predetermined depth on a surface facing the electrode assembly 11 among the surfaces forming the thickness of the sealant 16. That is, the venting pattern part 13a is formed along the extending direction of the electrode lead 15, that is, in the longitudinal direction.
[84]
At least a portion of the venting pattern portion 16a is located in an area overlapping the sealing portion 14 of the pouch case 12. Therefore, when gas is generated in the pouch case 12, the pressure is concentrated in the area where the venting pattern portion 16a is formed (refer to the arrow in FIG. 6), so that the pouch case 12 can be quickly released.
[85]
As described above, the venting pattern portion 16a is formed on the sealant 16 to partially reduce the adhesive force between the sealant 16 and the pouch case 12 so that venting can be generated in a desired area. In the battery module according to another embodiment of the present invention, the area where the venting pattern portion 16a is formed corresponds to the inner space of the support frame 30, and thus, when venting occurs, gas is intensively injected through the injection slit 32 It becomes possible to spray.
[86]
The venting pattern portion 16a may be formed on only one of both sides of the electrode lead 15 (see FIG. 7 ), but both sides of the electrode lead 15 to make venting more easily All of them may be formed (see Fig. 8).
[87]
Meanwhile, referring to FIGS. 9 and 10, the venting pattern portion 16a may have a shape in which the width becomes narrower toward the direction in which the electrode lead 15 is drawn out. As such, when the venting pattern portion 16a has a shape in which the width becomes narrower toward the direction in which the electrode lead 15 is drawn out, the effect of pressure concentration can be maximized to enable faster venting, and in particular, the venting pattern portion (16a) is formed, but it is possible to more reliably prevent the phenomenon that venting occurs in an area other than the area.
[88]
In particular, the venting pattern portion 16a may have a pointed wedge shape, as shown in FIG. 9, in which case the effect of pressure concentration is maximized to maximize the line L extending from the edge of the venting pattern portion 16a. ), the adhesion between the sealing tape 16 and the inner surface of the pouch case 12 can be easily released.
[89]
In addition, as shown in FIG. 10, the wedge-shaped venting pattern portions 16a may be formed to be spaced apart from each other along the longitudinal direction of the sealant 16, that is, perpendicular to the extending direction of the electrode lead 15. have.
[90]
[91]
Although the present invention has been described above by way of limited examples and drawings, the present invention is not limited by this and will be described below and the technical idea of ​​the present invention by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the equal scope of the claims.

WE Claim

[Claim 1]
A cell stack having an electrode lead and consisting of a first battery cell and a second battery cell stacked to face each other; A connector connecting between the electrode leads of each of the pair of battery cells; And it is provided on at least one side of the cell stack, a pair of lead slits to which the electrode lead is drawn and formed in a position corresponding to the connector and a passage through which the venting gas discharged when venting the battery cell is injected A support frame having an injection slit provided; Battery module comprising a.
[Claim 2]
The battery module according to claim 1, wherein an end of the electrode lead exposed to the outside of the lead slit is bent and supported by the support frame.
[Claim 3]
The battery module according to claim 1, wherein the injection slit is formed in a position corresponding to a space formed between each of the terrace portions of the first battery cell and the second battery cell.
[Claim 4]
The battery module according to claim 1, wherein the bonding portion between the support frame and the cell stack is sealed so that the venting gas can be discharged to the outside only through the injection slit.
[Claim 5]
The battery module according to claim 1, wherein a sealing member is interposed in an empty space formed between the inner surface of the lead slit and the electrode lead.
[Claim 6]
According to claim 1, The battery cell, Electrode assembly having an electrode tab; An electrode lead attached to the electrode tab; A pouch case accommodating the electrode assembly so that the electrode lead is drawn out; And at least one venting pattern part, the sealing tape interposed between the electrode lead and the inner surface of the pouch case; A battery module comprising a.
[Claim 7]
The battery module according to claim 6, wherein the venting pattern portion is a notch formed at a predetermined depth along an extending direction of the electrode lead.
[Claim 8]
The battery module according to claim 7, wherein the venting pattern portion has a shape in which the width gradually narrows along the extending direction of the electrode lead.
[Claim 9]
The battery module according to claim 8, wherein the venting pattern portion has a wedge shape.
[Claim 10]
The battery module according to claim 7, wherein the venting pattern parts are spaced apart from each other along the longitudinal direction of the sealing tape.
[Claim 11]
The battery module according to claim 7, wherein the pouch case has a sealing area formed at an edge, and at least a portion of the venting pattern portion is located within the sealing area.
[Claim 12]
The battery module according to claim 7, wherein the venting pattern portion is formed on both surfaces of the electrode lead.