Patent Publication Number: US-2019198832-A1

Title: Battery

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is based on and claims priority of Chinese Patent Application No. 201711444373.8, filed on Dec. 27, 2017. The entire disclosure of the above to identified application, including the specification and claims are incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present disclosure relates to a battery. 
     BACKGROUND OF THE INVENTION 
     The development of new energy vehicle technology has put forward higher requirements on cruising range and power performance of electric vehicles. As main power sources of the electric vehicles, battery modules are required to process higher energy density. Hence, increasing the energy density of the battery modules is a key issue which should be focused. 
     The battery module is a combination of battery cells laminated in series and in parallel. To increase the energy density of a battery module, one method is to increase grouping efficiency of the battery modules, which is generally achieved by lightweight design. However, it is difficult to balance reliability and economy during the lightweight design. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a battery, which includes a case and several bare cells located within the case. Each bare cell includes a first electrode, a second electrode and a separator. The first electrode includes a first empty-foil area and a first coating area. The first coating area is divided into two independent parts by the first empty-foil area. The separator is located between adjacent first electrode and second electrode to avoid short circuit between the first electrode and the second electrode. 
     At least two first electrodes are laminated together, and the laminated first electrodes are connected together via the first empty-foil area. Two second electrodes are disposed between the two adjacent first electrodes, and the two second electrodes are located at both sides of the first empty-foil areas separately. 
     The laminated first electrodes are welded together at the first empty-foil area and are electrically connected to a first tab of a pouch battery or a first electrode terminal of a prismatic battery. The two second electrodes which are located between two adjacent first electrodes are insulated with each other. 
     The first electrode includes a foil and a slurry coating formed thereon. The first coating area is formed by applying the slurry coating onto the foil of the first electrode, and the first empty-foil area refers to an area without applying the slurry coating. The first empty-foil areas of the laminated first electrodes are welded together in a way of ultrasonic welding, in this way, the first empty-foil areas are electrically connected with each other after welding. 
     The second electrodes at one side of the first empty-foil area are electrically connected to a second tab or a second electrode terminal of the battery, meanwhile, the second electrodes at the other side of the first empty-foil areas are electrically connected to a third tab or a third electrode terminal of the battery. 
     A polarity of the first electrode is different from that of the second electrode. In one embodiment, the first electrode is a positive electrode, the second electrode is a negative electrode. In another embodiment, the first electrode is a negative electrode, the second electrode is a positive electrode. 
     The case is a pouch-like case packaged with aluminum plastic film or prismatic metal case. 
     In one embodiment of the present disclosure, the second electrode includes a second empty-foil area and a second coating area. Both the second empty-foil area and the second coating area are distributed along a lateral direction or a longitudinal direction of the second electrode. Meanwhile, the second empty-foil area is disposed at outer end of the second electrode. 
     The outer end of the second electrode refers to the end of the second electrode away from the first empty-foil area. 
     The second electrode includes a foil and a slurry coating formed thereon. The second coating area is formed by applying the slurry coating onto the foil of the second electrode, and the second empty-foil area refers to an area without applying the slurry coating. 
     In one embodiment of the present disclosure, the second empty-foil areas at one side of the first empty-foil area are welded together and electrically connected to the second tab or the second electrode terminal of the battery. Meanwhile, the second empty-foil areas at the other side of the first empty-foil area are welded together and electrically connected to the third tab or the third electrode terminal of the battery. Therefore, the second empty-foil areas which are welded together are electrically connected with one another. 
     In an embodiment of the present disclosure, the case is a prismatic case, which includes a top cover, a first electrode terminal, a second electrode terminal and a third electrode terminal, the first electrode terminal, the second electrode terminal and the third electrode terminal are located on the top cover, the first electrode terminal is electrically connected with the first empty-foil area, the second electrode terminal is electrically connected with the second empty-foil areas at one side of the first empty-foil area. The third electrode terminal is electrically connected with the second empty-foil areas at the other side of the first empty-foil area. The first electrode terminal is disposed between the second electrode terminal and the third electrode terminal. A first explosion relief valve is arranged between the first electrode terminal and the second electrode terminal, and a second explosion relief valve is arranged between the first electrode terminal and the third electrode terminal. 
     In an embodiment of the present disclosure, the separator covers the surface of the second coating area. 
     In one embodiment, the separator surrounds the second coating area for at least one round, forming an annular structure. 
     In one embodiment, the separator wraps around the surface of the second coating area for at least one round, forming an annular structure, the second coating area is accommodated in the annular structure. Because of this, the first electrode is separated from the second electrode, and short circuit between the first electrode and the second electrode is prevented. 
     In one embodiment of the present disclosure, the separator is a pouch-like structure, and coats the second coating area. 
     The second coating area is hermetic-packaged in the pouch-like structure of the separator, because of this, the second electrode is separated from the first electrode, and short circuit between the first electrode and the second electrode is prevented. 
     The second coating area is hermetic-packaged in the pouch-like structure of the separator, because of this, a composite unit of the second electrode and the separator is formed. In the composite unit, the second electrode and the pouch-like separator are adhered together by hot pressing. 
     In one embodiment of the present disclosure, two opposite sides of the second coating area are symmetrically coated, two opposite sides of the second empty-foil area of the second electrode are symmetrically uncoated. 
     In one embodiment of the present disclosure, two opposite sides of the first coating area are symmetrically coated, two opposite sides of the first empty-foil area are symmetrically uncoated. 
     In one embodiment of the present disclosure, the first empty-foil area is located in the middle of the first electrode, and the first coating area is divided into two identical parts by the first empty-foil area. 
     In one embodiment of the present disclosure, the first electrode is a negative electrode, the second electrode is a positive electrode. 
     The first electrode includes a foil and a slurry coating, the foil of the first electrode is copper foil, and the slurry coating of the first electrode is formed by a negative slurry; the second electrode includes a foil and a slurry coating, the foil of the second electrode is aluminum foil, and the slurry coating of the second electrode is formed by a positive slurry. 
     In another embodiment of the present disclosure, the first electrode is a positive electrode, the second electrode is a negative electrode. 
     The first electrode includes a foil and a slurry coating, the foil of the first electrode is aluminum foil, and the slurry coating of the first electrode is formed by a positive slurry; the second electrode includes a foil and a slurry coating, the foil of the second electrode is copper foil, the slurry coating of the second electrode is formed by a negative slurry. 
     In one embodiment of the present disclosure, the battery is a pouch cell. In another embodiment of the present disclosure, the battery is a prismatic cell. 
     The battery of the present disclosure has the following advantages: 
     First, two adjacent first electrodes are parallel to each other and are connected at the first empty-foil areas thereof, two second electrodes are located between the two adjacent first electrodes and are separately disposed at both sides of the first empty-foil area thereof. Because of this, laminated bare cells are formed within one case, each includes a first electrode, a second electrode and a separator. Further, within two laminated bare cells, the positive electrodes and the negative electrodes are laminated and are in parallel connection in same case. Long in short, the first electrode terminal and the case are shared by multiple bare cells. Hence, a weight ratio of the case in the battery is reduced, and an energy density of the battery is improved. 
     Second, since the laminated first electrodes are connected at the first empty-foil area thereof and are electrically connected to same first electrode terminal, in other words, the laminated bare cells share same electrode terminal, parallel connection of laminated bare cells is realized in the absence of busbar assembly. Being lack of busbar assembly also helps improve the energy density of the battery module. 
     Third, the first empty-foil areas of the present disclosure are welded together such that the battery can dissipate heat through the welded first empty-foil areas welded together, which is advantageous to improve the heat dissipation capability of the first electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged cross-sectional view of the battery. 
         FIG. 2  is an enlarged explosive schematic view of the battery assembly process. 
         FIG. 3  is a schematic view of a first electrode. 
         FIG. 4  is a schematic view of a second electrode. 
         FIG. 5  is a schematic view of the second electrode and a separator. 
         FIG. 6  is a perspective view showing the connection state of a first empty-foil area and a second empty-foil area. 
         FIG. 7  is a schematic view of a top cover structure. 
         FIG. 8  is an enlarged schematic view of portion A in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the present disclosure will now be described more apparently and completely with reference to the embodiments. Obviously, the illustrated embodiments are only a part but not all of the embodiments of the present disclosure. All the other embodiments which could be obtained without creativity by one of ordinary skill in the art according to the illustrated embodiments would be claimed within the scope of the present disclosure. 
     Embodiment 1 
     As shown in  FIGS. 1 and 2 , a battery  100  is provided in this embodiment. The battery  100  includes a case  110  and several bare cells  120  located within the case  110 . Each bare cell  120  includes a first electrode  122 , a second electrode  124  and a separator  126 , the separator  126  is located between adjacent first electrode  122  and second electrode  124 . Because of this, short circuit between the first electrode  122  and the second electrode  124  is prevented. As shown in  FIG. 1 , the separator  126  is folded to define a space, and the second electrode  124  is accommodated therein. 
     As shown in  FIG. 3 , the first electrode  122  includes a first empty-foil area  1221  and a first coating area  1222 . The first coating area  1222  is divided into two independent parts  1223 ,  1224  by corresponding first empty-foil area  1221 , and the first empty-foil area  1221  is disposed in the middle of the first electrode  122 . In one embodiment, the first coating area  1222  is divided into two identical parts  1223  and  1224  by the first empty-foil area  1221 . Further, as shown in  FIG. 8 , regarding one of the first coating area  1222 , both sides of the first electrode  122 , i.e., an upper side  1225  and a lower side  1226 , are symmetrically arranged. In other words, both the upper side  1225  and the lower side  1226  are coated with first electrode slurry symmetrically. Meanwhile, as shown in  FIG. 2 , regarding the first empty-foil area  1221 , it is symmetrically arranged, that is, neither side of the first electrode  122  at the first empty-foil area  1221  is coated. 
     As shown in  FIGS. 2, 4 and 8 , the second electrode  124  includes a second empty-foil area  1241  and a second coating area  1242 . Further, the second empty-foil area  1241  and the second coating area  1242  are distributed along a lateral direction of the second electrode  124 . As shown in  FIGS. 2 and 8 , the second empty-foil area  1241  is disposed at outer end of the second electrode  124  away from the first empty-foil area  1221 . Regarding the second coating area  1242 , two opposite sides of the second coating area  1242  are symmetrically coated, for example with second electrode slurry, the two opposite sides refers to an upper side  1243  and a lower side  1244  of the second electrode  124  as shown in  FIG. 8 . In other words, both the upper side  1243  and the lower side  1244  of the second electrode  124  at the second coating area  1242  are applied, such as with second electrode slurry. Meanwhile, regarding the second empty-foil area  1241 , both sides of the second electrode  124  at the second empty-foil area  1241  are symmetrically arranged, i.e., both the upper side  1243  and the lower side  1244  at the second empty-foil area  1241  remain uncoated symmetrically. 
     As shown in  FIGS. 5 and 8 , the separator  126  covers the surface of the second coating area  1242 . Meanwhile, the separator  126  is folded and surrounds the second coating area  1242  for at least one round forming an annular structure, and the second coating area  1242  is accommodated therein. 
     As shown in  FIGS. 2 and 6 , the battery  100  includes at least two first electrodes  122  laminated together. The laminated first electrodes  122  are connected at the first empty-foil area  1221 , for example in a way of welding, and are further electrically connected to a first electrode terminal  132  of the battery. As shown in  FIG. 3 , with regard to one single first electrode  122 , two parts of the coating areas  1222  are mounted at opposite sides of the first empty-foil area  1221 ; further, the battery  100  includes at least two adjacent first electrodes  122  and two second electrodes  124 , wherein the two second electrodes  124  are separately sandwiched between two first electrodes  122  and located at both sides of the first empty-foil areas  1221  separately. 
     As shown in  FIGS. 2, 5, 6 and 8 , the second empty-foil areas  1241  at one side of the first empty-foil area  1221  are connected together, for example by welding, and further electrically connected to a second electrode terminal  134  of the battery. The second empty-foil areas  1241  at the other side of the first empty-foil area  1221  are connected together, for example in a way of welding, and further electrically connected to a third electrode terminal  136  of the battery. In one embodiment, the first electrode  122  is a negative electrode, the second electrode  124  is a positive electrode, the first electrode terminal  132  is a negative terminal, both the second electrode terminal  134  and the third electrode terminal  136  are positive terminals. 
     As shown in  FIGS. 1, 6 and 7 , the case  110  is prismatic, which includes a top cover  140 , the first electrode terminal  132 , the second electrode terminal  134  and the third electrode terminal  136 . The first electrode terminal  132 , the second electrode terminal  134  and the third electrode terminal  136  are located on the top cover  140 . The first electrode terminal  132  is electrically connected with the first empty-foil area  1221 , the second electrode terminal  134  is electrically connected to the second empty-foil areas  1241  which locate at one side of the first empty-foil area  1221 , the third electrode terminal  136  is electrically connected to the second empty-foil areas  1241  which locate at the other side of the first empty-foil area  1221 . The first electrode terminal  132  is disposed between the second electrode terminal  134  and the third electrode terminal  136 . A first explosion relief valve  142  is mounted between the first electrode terminal  132  and the second electrode terminal  134 , a second explosion relief valve  144  is mounted between the first electrode terminal  132  and the third electrode terminal  136 . 
     Embodiment 2 
     As shown in  FIGS. 1 and 2 , a battery  100  is provided in this embodiment. The battery  100  includes a case  110  and several bare cells  120  located within the case  110 . Each bare cell  120  includes a first electrode  122 , a second electrode  124  and a separator  126 , the separator  126  is arranged between adjacent first electrode  122  and second electrode  124 . Because of this, short circuit between the first electrode  122  and the second electrode  124  is prevented. 
     As shown in  FIG. 3 , the first electrode  122  includes a first empty-foil area  1221  and a first coating area  1222 . The first coating area  1222  is divided into two independent parts  1223 ,  1224  by corresponding first empty-foil area  1221 , and the first empty-foil area  1221  is disposed in the middle of the first electrode  122 . In one embodiment, the first coating area  1222  is divided into two identical parts  1223  and  1224  by the first empty-foil area  1221 . 
     As shown in  FIGS. 2 and 4 , the second electrode  124  includes a second empty-foil area  1241  and a second coating area  1242  adjacent thereto. Further, the second empty-foil area  1241  and the second coating area  1242  are distributed along a lateral direction of the second electrode  124 . As shown in  FIGS. 2 and 8 , the second empty-foil area  1241  is disposed at outer end of the second electrode  124  away from the first empty-foil area  1221 . The first electrode  122  is a positive electrode, the second electrode  124  is a negative electrode. 
     As shown in  FIGS. 5 and 8 , the separator  126  covers the surface of the second coating area  1242 . Meanwhile, the separator  126  forms a pouch-like structure, and surrounded the second coating area  1242 . 
     As shown in  FIGS. 2 and 6 , the battery  100  includes at least two first electrodes  122  laminated together. The laminated first electrodes  122  are connected at the first empty-foil area  1221 , for example in a way of welding. Further, the battery  100  includes at least two second electrodes  124 , and two second electrodes  124  are separately sandwiched between two adjacent first electrodes  122  and are located on both sides of the first empty-foil areas  1221 . 
     As shown in  FIGS. 2 and 5 , the second empty-foil areas  1241  at one side of the first empty-foil area  1221  are connected together, for example in a way of welding. Meanwhile, the second empty-foil areas  1241  at the other side of the first empty-foil area  1221  are connected together, for example in a way of welding. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.