This application is a priority claim application for Korean Patent Application No. 10-2017-0119764 filed on September 18, 2017, and all contents disclosed in the specification and drawings of the application are incorporated in this application by citation.
[2]
The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module and a battery pack including the same to apply a uniform pressure to the battery cell when swelling of the battery cell occurs.
Background
[3]
As technology development and demand for mobile devices have increased, demand for secondary batteries as an energy source has rapidly increased, and nickel cadmium batteries or hydrogen ion batteries have been used as secondary batteries, but memory effects have been recently compared to nickel-based secondary batteries. Lithium secondary batteries with high energy density are being used because charging and discharging are free, and self-discharge rate is very low.
[4]
The lithium secondary battery mainly uses a lithium-based oxide and a carbon material as a positive electrode active material and a negative electrode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate coated with the positive electrode active material and the negative electrode active material are disposed with a separator interposed therebetween, and an exterior material for sealingly storing the electrode assembly together with an electrolyte, that is, a battery case.
[5]
The lithium secondary battery is composed of a positive electrode, a negative electrode, a separator and an electrolyte interposed therebetween, and a lithium ion battery (Lithium Ion Battery, LIB), a lithium polymer battery (Polymer Lithium Ion Battery) depending on which positive electrode active material and negative electrode active material are used. , PLIB). Usually, the electrodes of these lithium secondary batteries are formed by applying a positive electrode or a negative electrode active material to a current collector such as aluminum or copper sheet, mesh, film, foil, and then drying them.
[6]
1(a) is a partial side cross-sectional view of a conventional battery module, and FIG. 1(b) is a partial side cross-sectional view of a swelling occurring in a battery cell in a conventional battery module to form uneven pressure on the battery cell and the end plate. to be.
[7]
1(a) and 1(b), a plurality of battery cells 2 may be stacked on the battery module 1. However, in the process of charging and discharging the battery cell 2, gas may be generated inside the battery cell 2, and the swelling in which the battery cell 2 expands and contracts due to the generated gas The phenomenon may occur repeatedly. On the other hand, the battery cell 2 and the end plate 3 at one end are in contact with each other, and the edge portions of the end plate 3 are connected to the upper and lower end plates 4 and 5, and thus upper and lower end plates. Since it is supported by (4, 5), it has a relatively high rigidity compared to the center of the end plate 3, and therefore, the end plate 3 is of the end plate 3 rather than the center of the end plate 3 The battery cell 2 is further pressed at the edge. That is, the expansion occurs smoothly in the center of the battery cell 2, which is pressurized with a relatively small pressure, rather than the edge portion of the battery cell 2, which is pressurized with a relatively large pressure, and thus, as shown in FIG. 1(b). As shown, when the swelling of the battery cell 2 occurs, the center portion of the battery cell 2 is swollen more than the edge of the battery cell 2. In this connection, referring to the arrow of FIG. 1(b), the pressure distribution increases from the center of the end plate 3 toward the edge of the end plate 3, that is, the pressure distribution is non-uniform. do. That is, since the battery cell 2 does not expand at the edge of the end plate 3, excessive pressure is applied.
[8]
However, when the swelling of the battery cell 2 occurs in this way, if an uneven pressure distribution is formed in the battery cell 2, the performance of the battery cell 2 deteriorates and the electrical connection is temporarily lost, resulting in sudden death. There is a problem that occurs.
Detailed description of the invention
Technical challenges
[9]
Therefore, the technical problem to be achieved by the present invention is to ensure that a uniform pressure is applied to the battery cell when a swelling of the battery cell occurs, thereby preventing a sudden death phenomenon from occurring in the battery cell and a battery pack including the same. Is to provide.
[10]
In addition, it is to provide a battery module and a battery pack including the battery module that can appropriately adjust the pressure applied to the battery cell in the design of the battery module.
Task resolution
[11]
According to an aspect of the present invention, a plurality of battery cells are provided, and a plurality of battery cells are stacked on each other, a battery cell stack; A casing surrounding the battery cell stack; And an elastic member coupled to the inner side of the casing to avoid interference with the battery cell so that a uniform pressure is formed in the battery cell when swelling of the battery cell occurs.
[12]
In addition, the casing is formed by combining a plurality of end plates, the elastic member is provided with a plurality of springs, the plurality of springs can be coupled to the edge of the end plates disposed on both sides of the casing, respectively. .
[13]
In addition, the casing is formed of a hexahedron in which six end plates are coupled, and the elastic member is provided with four springs and can be coupled to the four edges of the end plates at both ends.
[14]
Further, a first end plate among the plurality of end plates is disposed to be movable between other end plates, and the plurality of springs may be coupled to the first end plate.
[15]
Further, the first end plate and the second end plates disposed at predetermined positions based on the movement direction of the first end plate are spaced apart from each other, and when the first end plate moves, the first end plate and the first end plate The second end plates may be in contact with each other.
[16]
In addition, each of the first end plate and the second end plate may be formed with at least one of a coupling protrusion and a coupling groove that can be coupled to each other.
[17]
Meanwhile, according to another aspect of the present invention, a battery pack including the above-described battery module may be provided, and an automobile including the battery module may be provided.
Effects of the Invention
[18]
Embodiments of the present invention, there is an effect that can prevent the occurrence of sudden death in the battery cell by applying a uniform pressure to the battery cell when swelling of the battery cell through the elastic member.
[19]
In addition, by adjusting the spring constant of the elastic member, it is possible to properly adjust the pressure acting on the battery cell when designing the battery module.
Brief description of the drawing
[20]
1(a) is a partial side cross-sectional view of a conventional battery module, and FIG. 1(b) is a partial side cross-sectional view of a swelling occurring in a battery cell in a conventional battery module to form uneven pressure on the battery cell and the end plate. to be.
[21]
2 is a schematic cross-sectional view before cell swelling occurs in the battery module according to the first embodiment of the present invention.
[22]
3 is a schematic cross-sectional view when a cell swelling occurs in the battery module according to the first embodiment of the present invention.
[23]
4 is a schematic cross-sectional view before cell swelling occurs in a battery module according to a second embodiment of the present invention.
[24]
5(a) and 5(b) are schematic cross-sectional views of a state in which the first end plate moves to contact the second end plate when cell swelling occurs in the battery module according to the second embodiment of the present invention.
Mode for carrying out the invention
[25]
Hereinafter, with reference to the accompanying drawings will be described in detail according to a preferred embodiment of the present invention. The terms or words used in the present specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to best describe his or her invention. Based on the principle that it should be interpreted as a meaning and a concept consistent with the technical idea of ​​the present invention. Therefore, the embodiments shown in the embodiments and the drawings described in this specification are only 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.
[26]
In the drawings, the size of each component or a specific part constituting the component is exaggerated, omitted, or schematically illustrated for convenience and clarity. Therefore, the size of each component does not entirely reflect the actual size. When it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the description is omitted.
[27]
As used herein, the term'coupled' or'connected' means that one member and another member are directly coupled or directly connected, as well as one member indirectly coupled to another member through a joint member, or indirectly. It also includes the case where it is connected.
[28]
2 is a schematic cross-sectional view before cell swelling occurs in the battery module according to the first embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view when cell swelling occurs in the battery module according to the first embodiment of the present invention.
[29]
2 and 3, the battery module 10 according to the first embodiment of the present invention includes a battery cell stack 100, a casing 200, and an elastic member 300.
[30]
The battery cell stack 100 is provided with a plurality of battery cells 110 provided with electrode leads. The electrode lead provided in the battery cell 110 is exposed to the outside and may be a conductive material used as a terminal connected to an external device. The electrode lead may include a positive electrode lead and a negative electrode lead. The positive electrode lead and the negative electrode lead may be disposed in opposite directions to the longitudinal direction of the battery cell 110, or the positive electrode lead and the negative electrode lead may be in the same direction with respect to the longitudinal direction of the battery cell 110. It can also be located. The electrode leads can be electrically coupled to the busbar. The battery cell 110 is a battery unit (Bi-Cell) arranged in the order of a positive electrode plate-separator-negative electrode plate unit cell (Unit Cell) or a positive electrode plate-separator-negative electrode plate-separator-positive electrode plate-separator-negative electrode plate It may have a structure in which a plurality of layers are stacked according to a capacity.
[31]
The battery cell stack 100 may be configured such that a plurality of battery cells 110 are stacked with each other. Here, the battery cell 110 may have various structures, and a plurality of battery cells 110 may be stacked in various ways.
[32]
The battery cell stack 100 may be provided with a plurality of cartridges (not shown) that accommodate each battery cell 110. Each cartridge (not shown) may be manufactured by injection molding of plastic, and a plurality of cartridges (not shown) may be stacked with a storage unit capable of accommodating the battery cell 110. A connector element or a terminal element may be provided in a cartridge assembly in which a plurality of cartridges (not shown) are stacked. The connector element may include various types of electrical connection parts or connection members for connection to, for example, a battery management system (BMS) that can provide data on the voltage or temperature of the battery cell 110 or the like. have. The terminal element is a main terminal connected to the battery cell 110 and includes a positive terminal and a negative terminal, and the terminal element is provided with a terminal bolt to be electrically connected to the outside. Meanwhile, the battery cell 110 may have various shapes.
[33]
The casing 200 may contain a battery cell stack 100 or a cartridge assembly in which the battery cell stack 100 is stored. The casing 200 surrounds the entire battery cell stack 100 or a plurality of cartridge assemblies, thereby protecting the battery cell stack 100 or the cartridge assembly from external vibration or impact.
[34]
The casing 200 may be formed in a shape corresponding to the shape of the battery cell stack 100 or the cartridge assembly. For example, when the battery cell stack 100 or the cartridge assembly is provided in a hexahedral shape, the casing 200 may also be provided in a hexahedral shape to correspond thereto. The casing 200 may be manufactured by bending a metal plate, for example, or may be manufactured by injection molding of plastic. In addition, the casing 200 may be manufactured integrally or may be manufactured separately. The casing 200 may be formed with a through portion (not shown) through which the aforementioned connector element or terminal element may be exposed to the outside. That is, the connector element or the terminal element may be electrically connected to an external predetermined component or member, and a through portion may be formed in the casing 200 so that such electrical connection is not disturbed by the casing 200.
[35]
The casing 200 may be formed by combining a plurality of end plates 210. Here, the number of end plates 210 may vary, and for example, the casing 200 may be formed of a hexahedron in which six end plates 210 are combined. However, the casing 200 is not necessarily composed of six end plates 210, the number of end plates 210 may vary, and the shape of the casing 200 is not limited to a hexahedron, and the casing ( The shape of 200) may be more diverse. However, hereinafter, for convenience of description, the case 200 will be mainly described in the case of a hexahedral shape formed of six end plates 210.
[36]
The elastic member 300 is coupled to the inside of the casing 200 by avoiding interference with the battery cell 110, whereby a uniform pressure is formed in the battery cell 110 when swelling of the battery cell 110 occurs You can. 2, the elastic member 300 may be provided in various ways, for example, a plurality of springs. In addition, the plurality of springs may be coupled to the edge portions of the end plates 210 disposed at both ends of the hexahedral casing 200. The elastic member 300 may be provided with four springs, for example, and coupled to four edges of the end plates 210 at both ends. As described above, when the plurality of springs are respectively coupled to the end plates 210 of both ends of the casing 200, the battery cells 110 interposed between the end plates 210 of both ends of the casing 200 Can provide a uniform force. That is, as described above, referring to FIGS. 1(a) and 1(b), in the case of the conventional battery cell 2, when the swelling of the battery cell 2 occurs, the battery cell is less than the edge of the battery cell 2 (2) Since the center portion of the battery swells more, an uneven pressure distribution is formed in the battery cell 2 when the swelling of the battery cell 2 occurs, thereby deteriorating the performance of the battery cell 2 and instantaneous electrical connection. There is a problem in that a sudden death phenomenon occurs. However, in the case of the battery module 10 according to the first embodiment of the present invention, referring to FIG. 2, the edge portions of the end plates 210 at both ends of the casing 200,
[37]
On the other hand, when the elastic member 300 is provided as a spring, the spring constant can be appropriately adjusted, whereby the battery cell 110 is designed during the design of the battery module 10 so that a pressure desired by the user is applied to the battery cell 110. ) Pressure can be appropriately adjusted.
[38]
Hereinafter, the operation and effects of the battery module 10 according to the first embodiment of the present invention will be described with reference to the drawings.
[39]
2 and 3, the battery cell stack 100 is accommodated in the casing 200, and a plurality of springs provided in the elastic member 300 are coupled to the inner edge portion of the casing 200. And, when the swelling of the battery cell 110 occurs, the elastic force of the spring is provided at the edge portion of the end plate 210 that is relatively large in pressure compared to the center of the end plate 210, whereby the end plate 210 A uniform pressure distribution may be formed from the edge portion to the center of the end plate 210 as a whole.
[40]
4 is a schematic cross-sectional view before cell swelling occurs in a battery module according to a second embodiment of the present invention, and FIGS. 5(a) and 5(b) are cells in a battery module according to a second embodiment of the present invention It is a schematic cross-sectional view of a state in which the first end plate moves to contact the second end plate when swelling occurs.
[41]
Hereinafter, the operation and effects of the battery module 10 according to the second embodiment of the present invention will be described with reference to the drawings, but the parts common to those described in the battery module 10 according to the first embodiment of the present invention Is replaced by the above description.
[42]
The second embodiment of the present invention is different from the first embodiment in that the first end plate 211 may move to contact the second end plate 212.
[43]
Referring to FIG. 4, one fixed third end plate 213 is installed at one end of the casing 200, and the first end plate 211 is provided to be movable at the other end of the casing 200. And, the second end plate 212 is fixedly spaced apart from the first end plate 211 is installed. Here, the first end plate 211 is disposed between the third end plate 213 and the second end plate 212 fixed to one end of the casing 200 to be movable, and the first end plate ( 211) and a plurality of springs are respectively coupled to the third end plate 213. The first end plate 211 may be provided to be movable toward the second end plate 212, and when the swelling of the battery cell 110 is performed, the first end plate 211 moves to move the second end plate 212. ). Here, in each of the first end plate 211 and the second end plate 212, coupling protrusions 215 and coupling grooves 216 that can be coupled to each other are formed, and the first end of the battery cell 110 is swelled. When the end plate 211 moves toward the second end plate 212, when the coupling protrusions 215 and the coupling grooves 216 formed on the first end plate 211 and the second end plate 212 are engaged with each other, Since the contact portions of the first end plate 211 and the second end plate 212 can be kept in constant contact, the pressure distribution is uniform throughout the center of the end plate 210 from the edge of the end plate 210 In addition to being formed, there is an effect that a uniform pressure distribution can be continuously maintained.
[44]
Meanwhile, a battery pack (not shown) according to an embodiment of the present invention may include one or more battery modules 10 according to an embodiment of the present invention as described above. In addition, the battery pack (not shown), in addition to the battery module 10, the case 510 for storing the battery module 10, various devices for controlling charging and discharging of the battery module 10, such as BMS, current sensor, fuse, etc. may be further included.
[45]
Meanwhile, a vehicle (not shown) according to an embodiment of the present invention may include the above-described battery module 10 or a battery pack (not shown), and the battery module 10 is included in the battery pack (not shown). This can be included. In addition, the battery module 10 according to an embodiment of the present invention may be applied to a vehicle (not shown) provided to use electricity such as the vehicle (not shown), for example, an electric vehicle or a hybrid vehicle. You can.
[46]
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 by the person 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.
Industrial availability
[47]
The present invention relates to a battery module and a battery pack including the same, and is particularly applicable to industries related to secondary batteries.

WE Claim

[Claim 1]
A battery cell stack in which a plurality of battery cells are provided and a plurality of battery cells are stacked on each other; A casing surrounding the battery cell stack; And an elastic member coupled to the inside of the casing to avoid interference with the battery cell so that a uniform pressure is formed on the battery cell when swelling of the battery cell occurs.
[Claim 2]
The casing of claim 1, wherein the casing is formed by combining a plurality of end plates, the elastic member is provided with a plurality of springs, and the plurality of springs are provided at edges of end plates disposed on both sides of the casing. Battery module, characterized in that combined.
[Claim 3]
The battery module according to claim 2, wherein the casing is formed of a hexahedron in which six end plates are coupled, and the elastic member is provided with four springs and is coupled to the four edges of the end plates at both ends.
[Claim 4]
The battery of claim 2, wherein a first end plate among the plurality of end plates is disposed to be movable between other end plates, and the plurality of springs are coupled to the first end plate. module.
[Claim 5]
The method according to claim 4, wherein the first end plate and the second end plates disposed at predetermined positions based on the movement direction of the first end plate are spaced apart from each other, and when the first end plate is moved, The battery module, characterized in that the end plate and the second end plate can be in contact with each other.
[Claim 6]
The battery module according to claim 5, wherein at least one of a coupling protrusion and a coupling groove that can be coupled to each other is formed on each of the first end plate and the second end plate.
[Claim 7]
A battery pack comprising the battery module according to claim 1.
[Claim 8]
A vehicle comprising the battery module according to claim 1.