Battery case for an electric bicycle and a mounting structure thereof

BATTERY CASE INTERNAL VENTILATION STRUCTURE FORCONTROLLING THE TEMPERATURE THEREIN

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a battery case internal ventilation structurefor controlling the temperature therein, and more particularly to a heat dissipatingstructure for a battery case that is likely to be attenuated in service life whensubjected to high temperature.

Description of the Prior Arts

Along with the development of technology in battery industry, differentbattery modules (such as nicad battery, Ni-MH Battery, Li-ion battery and so on)have been widely used on many electric appliances, such as the notebook, thecamera, and the like. These battery modules can be easily used, however they arehigh in production cost and the service life will be attenuated if subjected to hightemperature. So far, the battery producer has not found any effective solution to thisproblem.

The battery’s service life is highly susceptible to temperature changes. Forexample, the working temperature of the Li-ion battery ranges from -20 °C to 60 °C,if the Li-ion battery is placed in an environment over 24 hours where the temperatureis higher than 60 °G (whatever the battery is in use or not), the service life of thebattery will be attenuated to below 30% of its initial value, and the Li-ion batterycannot be fully recharged any more. Hence, temperature not only has a great bearingon the battery’s service life, but also will affect the electric appliances using the battery.

For example, usually, people like to place the notebook in the car, and insummer, the car gets very hot under the sun and the temperature therein can beincreased up to 70-80 °C. In this case, the service life of and the effective function ofthe notebook’s battery inside the car will be substantially attenuated, thus resulting ina permanent damage to the battery.

For another example of the battery module used on the electric bicycle, thetemperature in summer ranging from 30-40 °C is within the acceptable range,however, the battery module is usually placed in the battery case, and thetemperature inside the battery case will be over 60 °C after being heated by the sun,so that if the battery module keeps staying in such a high temperature for a longperiod of time will cause sharp attenuation in service life, thus resulting in apermanent damage.

It can be concluded from the above description that temperature not onlyhas a great bearing on the service life and the efficiency of the battery, but alsorelatively limits the possible scope of application of the battery.

The present invention has arisen to mitigate and/or obviate theafore-described disadvantages.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a battery caseinternal ventilation structure for controlling the temperature therein, wherein the fanand a temperature controller get power directly from the cells inside the battery case,so they can be operated independently. Whatever the cells are in use, or not in use, or being recharged, the fan can be turned on automatically to cool down the batterycase whenever the temperature inside the battery case is over a predeterminedreference.

The present invention will become more obvious from the followingdescription when taken in connection with the accompanying drawings, which show,for purpose of illustrations only, the preferred embodiments in accordance with thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a battery case internal ventilation structure inaccordance with the present invention;

Fig. 2 is a cross sectional view of the battery case internal ventilationstructure in accordance with the present invention;

Fig. 3 is a top view of the battery case internal ventilation structure inaccordance with the present invention;

Fig. 4 is an operational view of the battery case internal ventilation structurein accordance with the present invention, wherein the fan is disposed at the outlets;

Fig. 5 is an operational view of the battery case internal ventilation structurein accordance with the present invention, wherein the fan is disposed at the inlets;

Fig. 6 shows two fans are disposed at the outlets of the battery case inaccordance with the present invention;

Fig. 7 shows the fans are disposed at the outlets and the inlets of the batterycase in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figs. 1-3, a battery case internal ventilation structure forcontrolling the temperature therein is shown and comprises: a battery case 10, atemperature controller 20 and at least a fan 30.

The battery case 10 is used for storage of a plurality of cells 11, at a side ofthe battery case 10 are formed a plurality of inlets 12 and at another side of the battercase 10 opposite the inlets 12 are provided a plurality of outlets 13. The respectivecells 11 are separated from each other and from the internal surfaces of the batterycase 10 by ventilation spaces 101.

The temperature controller 20 is electrically connected to the cells 11 forsensing and controlling the temperature inside the battery case 10 and serves tocontrol and change the output value in response to temperature changes in thebattery case. For example, the temperature controller 20 is a temperature resistorwhose resistance value is changeable according to temperature, namely, theresistance value of the temperature controller will be increased with the increase oftemperature, and vice versa.

The fan 30 can be disposed either at the inlets 12 or the outlets 13, and thefan 30, the temperature controller 20 and the cells 11 are connected in a loop, so thatthe fan 30 gets power from the cells 11 and is able to rotate under the control of thetemperature controller 20.

The operation of the present invention will be explained as follows:

For example, the cells are Li-ion based and its working temperature rangefrom -20 °C to 60 °C, if the Li-ion cells are used in the battery case of an electricbicycle, the temperature inside the battery case will be over 60 °C after being heated by the sun, so that the battery module will be permanently damaged.

The inlets 12 and the outlets 13 are provided at either side of the sealedbattery case 10, and at the inlets 12 or the outlets 13 is disposed the fan 30 (as shownin Figs. 4 and 5). The temperature controller 20, the fan 30 and the cells 11 areconnected in a loop, and the temperature controller 20 will turn on the fan 30 toexhaust heat out of the battery case 10 when the temperature in the battery case 10 ishigher than a predetermined reference (such as: 50 °C).

If the fan 30 is disposed at the outlets 13 as a discharge fan (as shown in Fig.4), fresh air will flow into and out of the battery case 10 via the inlets 12 and theoutlets 1 after flowing through the ventilation spaces 101 and the surfaces of therespective cells 11. And vice versa, if the fan 30 is disposed at the inlets 12 as aextraction fan (as shown in Fig. 5), fresh air will also flow into and out of the batterycase 10 via the inlets 12 and the outlets 1 after flowing through the ventilation spaces101 and the surfaces of the respective cells 11.

In other words, the fan 30 introduces cool air into and exhausts hot air outof the battery case 10, and thus, the battery case 10 is cooled down and thetemperature therein is decreased.

It is to be noted that the fan 30 and the temperature controller 20 get powerdirectly from the cells 11 inside the battery case 10, so they can be operatedindependently. Whatever the cells 11 are in use, or not in use, or being recharged, thefan 30 can be turned on automatically whenever the temperature inside the batterycase 10 is over a predetermined reference. This is a brand new concept to the batteryindustry.

In real application, a filter 40 can be provided at the inlets 12 and the outlets13 for preventing foreign materials entering the battery case 10.

In addition, the number of the fans 13 can be varied according to needs, asshown in Fig. 6, for example, two fans 13 are disposed at the outlets 13 to improvethe ventilation since there are many cells 11 in the battery case 10.

As further shown in Fig. 7, the fans also can be disposed both at the inlets12 and the outlets 13 so as to improve the ventilation effect.

While we have shown and described various embodiments in accordancewith the present invention, it should be clear to those skilled in the art that furtherembodiments may be made without departing from the scope of the presentinvention.