Patent Publication Number: US-2022216572-A1

Title: Insulator for secondary battery and secondary battery including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of the priority of Korean Patent Application 10-2019-0031578, filed on Mar. 20, 2019, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to an insulator for a secondary battery and a secondary battery including the same, and more particularly, to an insulator for a secondary battery, which minimizes an impact applied to an electrode assembly when compared to the related art and a secondary battery including the insulator. 
     BACKGROUND ART 
     Secondary batteries that are repetitively chargeable and dischargeable may be divided into pouch type secondary batteries, cylindrical type secondary batteries, and prismatic type secondary batteries according to their structures. 
     An electrode assembly having a structure in which electrodes and separators are alternately disposed is provided in a secondary battery, and an insulator may be provided on an upper or lower portion of the electrode assembly. 
     The insulator serves to electrically insulate the electrode assembly from other components. According to the related art, there is a problem that an impact is applied to the electrode assembly due to collision between the insulator and the electrode assembly and collision between the electrode assembly and other components that are adjacent to the electrode assembly while the secondary battery is used. In particular, when vibration is applied to the secondary battery from the outside, there is a problem that the secondary battery is deteriorated in durability due to an impact that is continuously applied to the electrode assembly. For example, when the impact or the vibration is applied to the electrode assembly, there is a problem that an electrode tab of the electrode assembly is separated from its original position to cause an abnormal operation of the secondary battery. 
     DISCLOSURE OF THE INVENTION 
     Technical Problem 
     Therefore, an object to be achieved by the present invention is to improve durability of a secondary battery by minimizing an impact applied to the electrode assembly due to an external impact or vibration. 
     Technical Solution 
     According to one aspect of the present invention for achieving the above object, an insulator for a secondary battery includes: a body part configured to define a body; and a buffer part adhering to a top surface of the body part, wherein the buffer part includes a plurality of protrusions that protrude upward, and the body part is made of a material different from that of the buffer part. 
     The buffer part may be made of a material having elasticity. 
     The buffer part may include polybutylene terephthalate, polypropylene, perfluoroalkoxy, or a rubber material. 
     A horizontal cross-section of each of the plurality of protrusions may have an elongated rod shape. 
     A horizontal cross-section of each of the plurality of protrusions may have a circular or oval shape. 
     Since the plurality of protrusions are connected to each other by a lower region of the buffer part, the plurality of protrusions may be integrally provided. 
     Since a top surface of the body part is exposed to the outside between the plurality of protrusions, the plurality of protrusions may be provided separately from each other. 
     An upper area of a surface of each of the plurality of protrusions may have a curved shape. 
     The plurality of protrusions may include: first protrusions in which the rod shape in the horizontal cross-section extends in a first direction (D 1 ); and second protrusions in which the rod shape in the horizontal cross-section extends in a second direction (D 2 ). 
     The first direction (D 1 ) and the second direction (D 2 ) may be perpendicular to each other. 
     According to another aspect of the prevent invention for achieving the above object, a secondary battery includes: a battery can having a structure in which an upper portion is opened; a top cap coupled to the upper portion of the battery can; an electrode assembly accommodated in the battery can; and the insulator for the secondary battery, which is provided to face a top or bottom surface of the electrode assembly. 
     The insulator may include: an upper insulator facing the top surface of the electrode assembly; and a lower insulator facing the bottom surface of the electrode assembly, wherein each of the plurality of protrusions of the upper insulator and the plurality of protrusions of the lower insulator may be provided to face the electrode assembly. 
     Advantageous Effects 
     According to the present invention, the impact applied to the electrode assembly due to the external impact or vibration may be minimized to improve the durability of the secondary battery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cross-sectional view illustrating a structure of a secondary battery according to the present invention. 
         FIG. 2  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a first embodiment of the present invention. 
         FIG. 3  is an enlarged side cross-sectional view illustrating the example of the structure of the insulator for the secondary battery according to the first embodiment of the present invention. 
         FIG. 4  is an enlarged side cross-sectional view illustrating another example of the structure of the insulator for the secondary battery according to the first embodiment of the present invention. 
         FIG. 5  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a second embodiment of the present invention. 
         FIG. 6  is an enlarged side cross-sectional view illustrating the example of the structure of the insulator for the secondary battery according to the second embodiment of the present invention. 
         FIG. 7  is an enlarged side cross-sectional view illustrating another example of the structure of the insulator for the secondary battery according to the second embodiment of the present invention. 
         FIG. 8  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a third embodiment of the present invention. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, structures of a secondary battery and an insulator for the secondary battery according to the present invention will be described with reference to the accompanying drawings. The secondary battery according to the present invention may be applied to a cylindrical type secondary battery or a prismatic type secondary battery. 
     Secondary Battery and Insulator for Secondary Battery 
       FIG. 1  is a side cross-sectional view illustrating a structure of a secondary battery according to the present invention. 
     As illustrated in  FIG. 1 , a secondary battery  10  according to the present invention may include a battery can  100  having a structure, in which an upper portion is opened, and a top cap  200  coupled to the upper portion of the battery can  100 . 
     An electrode assembly  300  may be accommodated in the battery can  100 . The electrode assembly  300  may have a structure in which electrodes and separators are alternately disposed. 
     Electrode tabs  310  and  320 , each of which has a shape protruding outward may be disposed on the electrode assembly  300 .  FIG. 1  illustrates a case in which a protruding first electrode tab  310  is disposed on an upper portion of the electrode assembly  300 , and a protruding second electrode tab  320  is disposed on a lower portion of the electrode assembly  300 . 
     Continuously, referring to  FIG. 1 , a current interrupt member  400  may be provided below the top cap  200 , and a safety vent  500  may be provided below the current interrupt member  400 . As illustrated in  FIG. 1 , a peripheral portion of a top surface of the current interrupt member  400  may be provided in close contact with a peripheral portion of a bottom surface of the top cap  200 , and a peripheral portion of a top surface of the safety vent  500  may be provided in close contact with a peripheral portion of a bottom surface of the current interrupt member  400 . The current interrupt member may be, for example, a PTC element. The safety vent  500  may be electrically connected to the first electrode tab  310 . 
     The secondary battery  10  according to the present invention may include an insulator  600  for the secondary battery (hereinafter, referred to as an ‘insulator’) provided to face the top or bottom surface of the electrode assembly  300 . Hereinafter, in this specification, the insulator facing the top surface of the electrode assembly  300  is referred to as an upper insulator  610 , and the insulator facing the bottom surface of the electrode assembly  300  is referred to as a lower insulator  620 .  FIG. 1  illustrates a case in which both the upper insulator  610  and the lower insulator  620  are provided. However, alternatively, the secondary battery  10  according to the present invention may be provided with only the upper insulator  610  or the lower insulator  620 . Also, the upper insulator  610  or the lower insulator  620  may be in close contact with the top or bottom surface of the electrode assembly  300 , respectively. Alternatively, the upper insulator  610  or the lower insulator  620  may be spaced a predetermined distance from the electrode assembly  300 . As described later, a plurality of protrusions  604   a  (see  FIGS. 2 to 8 ) may be disposed on the insulator  600 . When the upper insulator  610  is provided in the secondary battery  10  according to the present invention, the upper insulator  610  may be provided so that the plurality of protrusions of the upper insulator  610  face the electrode assembly  300 . When the lower insulator  620  is provided in the secondary battery  10  according to the present invention, the lower insulator may be provided so that the plurality of protrusions  620  of the lower insulator faces the electrode assembly  300 . 
       FIG. 2  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a first embodiment of the present invention. 
     As illustrated in  FIG. 2 , an insulator  600  according to the present invention may include a body part  602  defining a body and a buffer part  604  adhering to a top surface of the body part  602 . The buffer part  604  may be configured to absorb an impact applied to the electrode assembly when an impact or vibration is applied to the secondary battery or the electrode assembly from the outside. A hole H may be defined in a central portion of the insulator  600 . 
     Also, since the insulator  600  is configured to electrically insulate the electrode assembly  300  from other components, it is necessary that an area of the insulator  600 , which faces or directly contacts the electrode assembly  300 , is made of a material having electrical insulating properties. 
     Thus, the buffer part  604  of the insulator  600  may be made of a material having electrical insulation and elasticity so that the electrode assembly is electrically insulated from other components while effectively absorbing the impact applied to the electrode assembly. For example, the buffer part  604  may include or be made of polybutylene terephthalate, polypropylene, perfluoroalkoxy, or a rubber material. 
     In the insulator  600  according to the present invention, the material of the body part  602  may be different from that of the buffer part  604 . The body part  602  may be made of a metal material. For example, the body part  602  may be made of stainless steel or aluminum. When the body part  602  is made of the metal material, since overall rigidity of the insulator  600  increases, even if an external impact is applied, the insulator  600  may normally operate without deforming a shape of the insulator  600 . Here, in order to more effectively improve the rigidity of the insulator  600 , it is preferable that the body part  602  is formed in a manner in which a flat metal plate having a constant thickness is bonded to one surface of the buffer part  604  rather than that metal powder is applied on the surface of the buffer part  604  at a thin thickness having a thin film level and then sintered. 
       FIG. 3  is an enlarged side cross-sectional view illustrating the example of the structure of the insulator for the secondary battery according to the first embodiment of the present invention, and  FIG. 4  is an enlarged side cross-sectional view illustrating another example of the structure of the insulator for the secondary battery according to the first embodiment of the present invention. 
     As illustrated in  FIGS. 2 and 3 , the buffer part  604  of the insulator  600  according to the present invention may include a plurality of protrusions  604   a  that protrude upward. The plurality of protrusions  604   a  may be configured to face the electrode assembly  300  (see  FIG. 1 ). When an impact or vibration is applied to the secondary battery or the electrode assembly, the plurality of protrusions  604   a  of the buffer parts  604  may absorb the impact applied to the electrode assembly to improve durability of the secondary battery. 
     Here, as illustrated in  FIGS. 2 and 3 , according to the first embodiment of the present invention, the buffer part  604  of the insulator  600  may have a wave-like wave shape. This may be understood that a horizontal cross-section of each of the plurality of protrusions  604   a  of the buffer part  604  has an elongated rod shape. 
     Also, as illustrated in  FIG. 3 , according to an example of the first embodiment of the present invention, the plurality of protrusions  604   a  may be connected to each other by a lower region of the buffer part  604  so that the plurality of protrusions  604   a  are integrally formed. 
     However, as illustrated in  FIG. 4 , according to another example of the first embodiment of the present invention, the plurality of protrusions  604   a  may be provided separately from each other. Therefore, as illustrated in  FIG. 4 , a top surface of the body part  602  may be exposed to the outside between the plurality of protrusions  604   a.    
       FIG. 5  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a second embodiment of the present invention, and  FIG. 6  is an enlarged side cross-sectional view illustrating the example of the structure of the insulator for the secondary battery according to the second embodiment of the present invention. Also,  FIG. 7  is an enlarged side cross-sectional view illustrating another example of the structure of the insulator for the secondary battery according to the second embodiment of the present invention. 
     As illustrated in  FIGS. 5 and 6 , according to the second embodiment of the present invention, a buffer part  604  of an insulator  600  may have an embossed shape. This may be understood that a horizontal cross-section of each of the plurality of protrusions  640   a  of the buffer part  604  has a circular or oval shape. 
     Also, as illustrated in  FIG. 6 , according to an example of the second embodiment of the present invention, a plurality of protrusions  604   a  may be connected to each other by a lower region of the buffer part  604  so that the plurality of protrusions  604   a  are integrally formed. 
     However, as illustrated in  FIG. 7 , according to another example of the second embodiment of the present invention, the plurality of protrusions  604   a  may be provided separately from each other. Therefore, as illustrated in  FIG. 7 , a top surface of the body part  602  may be exposed to the outside between the plurality of protrusions  604   a.    
       FIG. 8  is a perspective view illustrating an example of a structure of an insulator for a secondary battery according to a third embodiment of the present invention. 
     As illustrated in  FIG. 8 , according to the third embodiment of the present invention, a buffer part  604  of an insulator  600  may a wave shape in which waves overlaps each other. This may be understood that a horizontal cross-section of a plurality of protrusions  604   a  of the buffer part  604  has an elongated rod shape, and the plurality of protrusions  604   a  include first protrusions in which the rod shape in the horizontal cross-section extends in a first direction D 1  and second protrusions in which the rod shape in the horizontal cross-section extends in a second direction D 2 . Here, as illustrated in  FIG. 8 , the first direction D 1  and the second direction D 2  may be perpendicular to each other. That is, the directions in which the rod shapes of the horizontal cross-sections of the first protrusions and the second protrusions extend may be perpendicular to each other. 
     An upper area of a surface of each of the plurality of protrusions provided on the buffer part  604  according to the present invention may have a curved surface. Therefore, even if the electrode assembly and the buffer part contact each other, the problem in which the electrode assembly is damaged by the plurality of protrusions may be minimized. 
     While the embodiments of the present invention have been described with reference to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. 
     DESCRIPTION OF THE SYMBOLS 
       10 : Secondary battery 
       100 : Battery can 
       200 : Top cap 
       300 : Electrode assembly 
       310 : First electrode tab 
       320 : Second electrode tab 
       400 : Current interrupt member 
       500 : Safety vent 
       600 : Insulator 
       602 : Body part 
       604 : Buffer part 
       604   a : Protrusion 
       610 : Upper insulator 
       620 : Lower insulator 
     H: Hole 
     D 1 : First direction 
     D 2 : Second direction