Patent Publication Number: US-2011074358-A1

Title: Battery  Protection Device which Utilizes Light Current to Control Heavy Current

Description:
BACKGROUND OF THE INVENTION 
     a) Field of the Invention 
     The present invention relates to a technology by which recharging and discharging of large current can be controlled with a battery protection board. 
     b) Description of the Prior Art 
     It is known that a battery is an important energy tool. In order to develop new energy, more and more kinds of batteries arise and their application is getting broader and broader. In terms of the recharging and discharging characteristics as well as operation properties, the batteries can be generally divided into a primary cell and a secondary cell, wherein the secondary cell refers to the battery that can be reused. Hence, the secondary cell is more economical in cost and is therefore widely appreciated by general public, which is also the subject of the present invention. 
     When a battery is recharging or discharging, in order to apply the battery more safely and to prolong a lifetime of usage of the battery, some higher end battery will be installed with a protection circuit board to measure an application status of the battery and to detect variations of voltage and temperature during recharging or discharging, such that if an abrupt short-circuit occurs, the recharging or discharging of the battery can be turned off immediately, thereby achieving an object of protecting the battery and the circuit, and preventing from an ordeal by innocence. The aforementioned protection circuit device is widely available in an ordinary circuit design, such as a control and protection device for recharging and discharging a power generator, a Lithium-ion battery recharging and discharging circuit structure, and a battery recharging and discharging control circuit. Although these devices have different structures and features, they are all constituted by electronic elements, such as capacitors, resistors, diodes and triodes, which can only sustain with light current. Therefore, under a limitation of using the light current, it will spend a very long time to recharge or discharge the battery. Accordingly, in this busy industrial society, demands cannot be satisfied at all. On the other hand, if large current is introduced by taking a risk, then the electronic elements can be burned down easily. Hence, this issue has been always a bottleneck in the industry and could not be broken through. 
     To recharge the battery into which large current should be introduced, there is only one protection device design called MOS (Metal-Oxide Semiconductor) to control an on or off of current. However, as MOS should be kept at an energized state to achieve a control effect, there are two shortcomings. The first shortcoming is that MOS consumes more electricity. The second one is that when large current passes through MOS, high heat will occur. To solve an issue of heat dissipation derived from the high heat, an electric fan is usually installed on MOS for cooling. Thus, size and weight of the device will be increased correspondingly; in a mean time, more energy will be consumed. On the other hand, if the electric fan is damaged and is not replaced in time that the high heat cannot be expelled in time, then related electronic equipment will be burned down easily, or surrounding objects can be even affected to start a fire, which is a shortcoming of MOS and is also an issue that is eager to be solved by the related industry. 
     The aforementioned problems can be solved by a better circuit structure design. Therefore, a brand new battery protection device is specifically designed, such that the battery can be applied safer and can save energy. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a battery protection device which utilizes light current to control heavy current, wherein a conventional micro control unit (MCU) employs a light current system to carry out certain detection and determination, and then to transmit an “off” or “on” instruction to a relay control circuit, corresponding to a status of determination according to required conditions that are pre-configured. Next, the relay control circuit will send the “off” or “on” instruction to a latching relay, so as to control whether battery current can be recharged (discharged). Furthermore, since current and voltage of a coil of the latching relay for controlling close-circuit or open-circuit are very low, whereas current that can flow through a contact can be very large, an effect that small current (light current) controls large current (heavy current) can be achieved, thereby protecting the safety of and prolonging the lifetime of usage of the battery. 
     Accordingly, the present invention includes a circuit board on which is serially connected with at least two batteries to assemble into a battery supply unit. The battery supply unit is connected with an MCU through a sampling circuit, and transmits this message to the MCU as a reference of determination for controlling other units according to data configured by a program. The MCU can be connected respectively with a power supply loop and a base voltage loop of a voltage regulation system, and then forms a complete loop with the battery supply unit. That loop is further serially connected with a latching relay and a relay control circuit; whereas, a jaw and a contact of the latching relay are kept at a normally connected state magnetically, and the relay control circuit performs an on or off function to the relay depending upon determination of the MCU on voltage data of each electrode. 
     To enable a further understanding of the said objectives and the technological methods of the invention herein, the brief description of the drawings below is followed by the detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic view of a basic structure of the present invention. 
         FIG. 2  shows a flow diagram of an operation of the present invention. 
         FIG. 3  shows a schematic view of an action of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , the present invention comprises primarily a circuit board, on which is serially connected with at least two batteries  41  to assemble into a battery supply unit  40  (in this drawing, four batteries are used as an example of implementation). The battery supply unit  40  is connected with an MCU  10  through a sampling circuit  20 , with a lead wire  70  being connected at an electrode  42  between every two batteries  41  to the sampling circuit  20 . The sampling circuit  20  accesses voltage of each electrode  42  and then transmits this message to the MCU  10  which uses data pre-configured by a program to serve as a reference of determination for controlling other units. 
     The MCU  10  can be connected respectively with a power supply loop  30  and a base voltage loop  31  of a voltage regulation system, and then forms a loop with the battery supply unit  40 . The loop is a kind of electronic control circuit which can apply light current. 
     The loop is further serially connected with a latching relay  50  and a relay control circuit  21 . A jaw  51  and a contact  52  of the latching relay  50  are kept at a normally connected state magnetically, and the relay control circuit  21  performs an on or off control function to the latching relay  50  depending upon determination of the MCU  10  on the voltage data of each electrode  42 . 
     The MCU  10  can be also connected with a signal indication light  60  which illuminates different colors when various conditions appear, such that messages for recharging or discharging can be differentiated and provided to facilitate determining an existing action status of the protection board. 
     The sampling circuit  20  can have a different design according to a number of batteries  41  that are serially connected, acquiring a proper voltage value at the proper electrode  42  to provide the MCU  10  for determination. 
     Referring to  FIG. 1  and  FIG. 2 , the jaw  51  and contact  52  on the latching relay  50  are kept at the normally connected state magnetically. If the voltage of each electrode  42  in the battery supply unit  10  is within a normal range, then the MCU  10  will not issue any instruction to the relay control circuit  21 . On the other hand, if the voltage of each electrode  42  in the battery supply unit  40  is determined to be abnormal, then, as shown in  FIG. 3 , an instruction will be issued to the relay control circuit  21  which will send out control current to break off the jaw  51  and contact  52  of the latching relay  50 . At this time, as the power supply unit  40  cannot supply electricity to all external elements, all recharging circuits cannot recharge the power supply unit  40  either. Therefore, the battery protection effect has been achieved. 
     At this time, if re-energizing is to be performed, then a Reset button  500  should be pressed first (as this is an ordinary electronic and circuit technology, no further description is included in the drawings), and electricity will be supplied to the entire control loop momentarily. Then, a normal condition is restored again, until that the MCU  10  detects the abnormality once more to proceed another cycle. 
     In the present invention, the conventional MCU circuit utilizes the light current system to perform certain detection and determination operations, and then transmits the “off” or “on” instruction to the relay control circuit corresponding to the condition of determination according to the pre-configured required conditions. Next, the relay control circuit will send the “off” or “on” instruction to the latching relay to control whether the battery current can be recharged or discharged. As the current and voltage of the coil of the latching relay for controlling the close-circuit or open-circuit are very low, whereas the current that can flow through the contact can be very large, the object of using the small current (light current) to control the large current (heavy current) can be achieved, thereby protecting the safety of and prolonging the lifetime of usage of the battery. 
     It is of course to be understood that the embodiments described herein is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.