Battery unit, lithium polymer battery using the same, and method for manufacturing lithium polymer battery

Abstract

A battery unit with improved safety measures, a lithium polymer battery using the battery unit, and a method for manufacturing the lithium polymer battery are provided. The lithium polymer battery has a battery unit and a case accommodating the battery unit, wherein the battery unit includes: a cathode plate having a cathode collector and a cathode active material layer coated on at least one surface of the cathode collector; a cathode lead electrically connected to the cathode collector; an anode plate having an anode collector and an anode active material layer coated on at least one surface of the anode collector; an anode lead electrically connected to the anode collector; a separator interposed between the cathode plate and the anode plate, which insulates the cathode plate and the anode plate from each other; and an insulating member formed on at least one of the cathode lead and the anode lead, which prevents a short circuit between the cathode lead and the anode plate or between the anode lead and the cathode plate. In the battery unit, the cathode plate, the separator, and the anode plate are sequentially and repeatedly stacked upon one another. Therefore, the insulating member incorporated in the lithium polymer battery can enhance the safety of the battery.

What is claimed is: 
     
       1. A method for manufacturing a lithium polymer battery, comprising steps of:
 mixing source materials for an electrode active material layer;   coating at least one surface of a collector substrate with the mixture of the source materials in a pattern corresponding to the electrode active material layer;   cutting the collector substrate with the pattern of the electrode active material layer into individual collectors;   attaching an electrode terminal to an electrode lead winding a sealing tape on a portion of the electrode terminal that will be in contact with a sealing portion of a battery case;   pre-attaching an insulating member to the electrode lead extending from each of the collectors;   thermally fusing the insulating member to the electrode lead; and   completing formation of an electrode plate including the collector which has the electrode active material layer and the electrode lead which extends from the collector and to which the insulating member is fused.   
     
     
       2. The method of  claim 1 , wherein in pre-attaching the insulating member to the electrode lead, a polypropylene tape is attached around a portion of the electrode lead. 
     
     
       3. The method of  claim 1 , wherein in pre-attaching the insulating member to the electrode lead, a polyethylene tape is attached around a portion of the electrode lead. 
     
     
       4. The method of  claim 1 , wherein in pre-attaching the insulating member to the electrode lead, an amorphous polyamide tape is attached around a portion of the electrode lead. 
     
     
       5. A method for manufacturing a lithium polymer battery, comprising:
 coating at least one surface of a collector substrate with an electrode active material layer;   cutting the coated collector substrate into individual collectors, each individual collector having an electrode lead extending from the collector;   attaching an insulating member to the electrode lead;   thermally fusing the insulating member to the electrode lead;   attaching an electrode terminal to the electrode lead having the thermally fused insulating member, the electrode lead being arranged between the collector and the electrode terminal and winding a sealing tape on a portion of the electrode terminal that will be in contact with a sealing portion of a battery case.   
     
     
       6. The method of  claim 5 , wherein attaching the insulating member to the electrode lead comprises attaching a polypropylene tape around a portion of the electrode lead. 
     
     
       7. The method of  claim 5 , wherein attaching the insulating member to the electrode lead comprises attaching a polyethylene tape around a portion of the electrode lead. 
     
     
       8. The method of  claim 5 , wherein attaching the insulating member to the electrode lead comprises attaching an amorphous polyamide tape around a portion of the electrode lead. 
     
     
       9. The method of  claim 5 , further comprising winding a sealing tape around a portion of the electrode terminal. 
     
     
       10. The method of  claim 5 , wherein coating at least one surface of a collector substrate with an electrode active material layer comprises:
 mixing source materials for the electrode active material layer; and coating the at least one surface of the collector substrate with the mixture of the source materials in a pattern corresponding to the electrode active material layer.   
     
     
       11. A secondary battery, comprising:
 a plurality of cathode plates each comprising a cathode collector, a cathode lead having a bent U-shape, and a cathode active material layer coated on at least one surface of the cathode collector;   a cathode terminal attached to the cathode leads;   a plurality of anode plates each comprising an anode collector, an anode lead, and an anode active material layer coated on at least one surface of the anode collector;   an anode terminal attached to the anode leads;   a separator interposed between the cathode plates and the anode plates, thereby insulating the cathode plates and the anode plates from each other;   an insulating member arranged around each of the cathode leads, each of the anode leads, or both of each of the cathode leads and each of the anode leads; and   a sealing tape arranged on a portion of the cathode terminal in contact with a sealing portion of a battery case, a portion of the anode terminal in contact with a sealing portion of a battery case, or both the portion of the cathode terminal and the portion of the anode terminal in contact with a sealing portion of a battery case.   
     
     
       12. The secondary battery of claim 11, wherein the insulating member comprises a polypropylene, a polyethylene, or an amorphous polyimide. 
     
     
       13. The secondary battery of claim 11, wherein the insulating member is arranged between the cathode plates and the cathode terminal, between the anode plates and the anode terminal, or both between the cathode plates and the cathode terminal and between the anode plates and the anode terminal. 
     
     
       14. The secondary battery of claim 11, wherein the insulating member has a width in the range of about 2 mm to 4 mm. 
     
     
       15. The secondary battery of claim 11, wherein the insulating member has a width in the range of about 1.5 mm to 4.5 mm. 
     
     
       16. The secondary battery of claim 15, wherein the insulating member has a length in the range of about 2.0 mm to 2.5 mm. 
     
     
       17. The secondary battery of claim 11, wherein the insulating member is arranged on each of the anode leads only, the insulating member being arranged around a portion of each of the anode leads arranged near the cathode plate. 
     
     
       18. The secondary battery of claim 11, wherein each cathode plate further comprises the cathode lead extending from and integrally formed with the cathode collector, and
 wherein each anode plate further comprises the anode lead extending from and integrally formed with the anode collector.   
     
     
       19. The secondary battery of claim 11, wherein the insulating member is arranged around a portion of each of the cathode leads arranged near the anode plate, a portion of each of the anode leads arranged near the cathode plate, or both the portion of each of the cathode leads arranged near the anode plate and the portion of each of the anode leads arranged near the cathode plate.