As mobile devices have been increasingly developed, and the demand of such mobile devices has increased, the demand of battery cells has also sharply increased. Among them is a lithium battery cell having high energy density and operating voltage and excellent preservation and service-life characteristics, which has been widely used as an energy source for various electronic products as well as for the mobile devices.
Based on their external and internal structures, battery cells are generally classified into a cylindrical battery, a prismatic battery, and a pouch-shaped battery. Especially, the prismatic battery and the pouch-shaped battery, which can be stacked with high integration and have a small width to length ratio, have attracted considerable attention.
Also, the battery cells have attracted considerable attention as an energy source for electric vehicles and hybrid electric vehicles, which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel. As a result, kinds of applications using the battery cells are being increased owing to advantages of the battery cells, and hereafter the battery cells are expected to be applied to more applications and products than now.
As kinds of applications and products, to which the battery cells are applicable, are increased, kinds of batteries are also increased such that the batteries can provide powers and capacities corresponding to the various applications and products. Furthermore, there is a strong need to reduce the sizes and weights of the batteries applied to the corresponding applications and products.
For example, small-sized mobile devices, such as mobile phones, personal digital assistants (PDA), digital cameras, and laptop computers, use one or several small-sized, light-weighted battery cells for each device according to the reduction in size and weight of the corresponding products. On the other hand, middle- or large-sized devices, such as electric vehicles and hybrid electric vehicles, use a middle- or large-sized battery module (which may be referred to as a “battery pack”) having a plurality of battery cells electrically connected with each other because high power and large capacity is necessary for the middle- or large-sized devices. The size and weight of the battery module is directly related to the receiving space and power of the corresponding middle- or large-sized device. For this reason, manufacturers are trying to manufacture small-sized, light-weighted battery modules.
Meanwhile, as battery cells are connected to one another, while the battery cells are stacked, to increase the capacities of battery modules, the dissipation of heat from the battery cells becomes serious. Heat is generated from lithium battery cells during the charge and discharge of the lithium battery cells. If the heat is not effectively removed, the heat accumulates in the respective lithium battery cells, with the result that the deterioration of the lithium battery cells is caused, and the safety of the lithium battery cells is greatly lowered. In particular, for a battery requiring high-speed charging and discharging characteristics as in a power source for electric vehicles and hybrid electric vehicles, a large amount of heat is generated from the battery at the time when the battery instantaneously provides high power.
Also, a laminate type battery case of a pouch-shaped battery widely used in the battery module is coated with a polymer material exhibiting low heat conductivity, with the result that it is difficult to effectively lower the overall temperature of the battery.
In connection with this matter, for example, Japanese Patent Application Publication No. 2005-302502 discloses a case for supporting a battery cell including a battery element of which the outer surface is formed of a laminate film and cathode and anode terminals for charge and discharge connected to the battery element, the cathode and anode terminals extruding from the laminate film, wherein a plate member having a plurality of empty spaces constitutes an upper body of a frame, the plate member being connected to another plate member in the thickness direction thereof, the inner circumferential part of the upper body of the frame serves as a support part for supporting four points of the battery element around the battery element, and the inner circumferential part of the upper body of the frame communicates with the outer circumferential part of the upper body of the frame such that the empty spaces are connected to one another. However, the above-mentioned technology has problems in that it is necessary to manufacture a battery cell case in a complicated structure and mount the battery cell case to a battery, which is troublesome, and, when batteries are stacked to manufacture a battery module, the thickness and volume of the battery module are greatly increased.
Therefore, there is a high necessity for a technology that is capable of fundamentally solving the above-mentioned problems.