Abstract:
Microbatteries based on liquid electrolyte are provided suitable for disposable microsystems including MEMS and bioMEMS. Systems using disposable and on-demand microbattery are also provided. Microbattery consists of a substrate, an anode supplying electrons when the anode contact to an electrolyte, a sealed liquid pocket including liquid mixture of an electrolyte and a cathode, a pressing means to generate pressure in said sealed liquid pocket, breaking means that is easily torn or removed by the pressure generated in said, liquid pocket, conducting electron collectors collecting electron to assist cathodic reaction and a cavity. Surface tension drives said liquid mixture into said cavity after tearing said breaking means, then electro-chemical reaction occurs to activate the microbattery. Water or blood activated microbattery is also provided for bioMEMS.

Description:
BRIEF DESCRIPTION OF THE DRAWINGS  
       [0001]      FIG. 1-1  is a perspective view of a microbattery embodying the principles of this invention.  
         [0002]      FIG. 1-2  is a side view of a microbattery (cross section A of  FIG. 1-1 ).  
         [0003]      FIG. 1-3  is a working principle of a microbattery showing in  FIG. 1-2 .  
         [0004]      FIGS. 2, 3  and  4  are embodiments using present invention concept.  
         [0005]      FIG. 5  is a system using microbattery of the invention.  
         [0006]      FIG. 6  is a cross section of the system of  FIG. 5  (cross section B of  FIG. 5 ).  
         [0007]      FIG. 7  is a DNA chip system using present invention concept.  
         [0008]      FIG. 8  is a signal flow of  FIG. 7 .  
         [0009]      FIG. 9  is another embodiment of DNA chip system.  
         [0010]      FIG. 10  is a signal flow of  FIG. 9 .  
         [0011]      FIGS. 11-1 ,  11 - 2  and  11 - 3  are embodiments of blood-examining systems with test needle.  
         [0012]      FIG. 12  is a schematic diagram of better needle.  
         [0013]      FIGS. 13, 14  and  15  are embodiments of blood-examining systems with different needles.  
         [0014]      FIG. 16  is a stacked microbattery fabricated on a substrate.  
         [0015]      FIGS. 17-1  and  17 - 2  are drug delivery systems embodying the systems of the invention.  
       BACKGROUND OF THE INVENTION  
       [0016]     1. Field of the Invention  
         [0017]     The present invention relates to a microbattery and systems using microbatteries that can be used for MEMS (Micro Electro Mechanical Systems) or bioMEMS.  
         [0018]     2. Description of the Related Arts  
         [0019]     Recently, many researchers and companies have done research on MEMS (Micro Electro Mechanical Systems) or micromachine. Much achievement in the MEMS or bioMEMS area has been done. Currently, researchers are interested in lab-on-a-chip, DNA chip, optical microsystems and microtransceiver because these have big potential market in Microsystems in the future. Using batch process such as bulk and surface micromachining technology, these MEMS or bioMEMS devices can be easily fabricated with microactuator, microsensor and circuits on a substrate. For example, lab-on-a-chip can be used to do several experiments using a droplet of a liquid on a chip at the same time. These technologies will play an important role in the future.  
         [0020]     Currrent MEMS or bioMEMS technologies have a bottleneck of energy source. Although Microsystems such as lab-on-a-chip or DNA chip are fabricated on a chip, the current microsystems need electrical energy from outside conventional battery or light energy for detection.  
       SUMMARY OF THE INVENTION  
       [0021]     It is an objective of the present invention to provide a microbattery and systems using a microbattery. The microbattery or systems can be activated by a sealed electrolyte or even water obtained blood. Disposable system with microbattery can be fabricated on a substrate by using several technologies including surface micromachining technology, bulk micromachining technology, conventional technology, etc.  
         [0022]     To achieve the above objective, a microbattery including in combination consists of: a substrate; an anode supplying electrons when the anode contact to an electrolyte; a sealed liquid pocket including liquid mixture of an electrolyte and a cathode; a pressing means to generate pressure in said sealed liquid pocket; a breaking means that is easily torn or removed by the pressure generated in said; liquid pocket; conducting electron collectors collecting electron to assist cathodic reaction; a cavity which said anode, said electron collector, and said breaking means contact to, where surface tension drives said liquid mixture into said cavity after tearing said breaking means, then electro-chemical reaction occurs to activate the microbattery.  
         [0023]     In addition to this invention, the following in any combination may provide better microbattery. 
        said cavity has at least one air holes to remove air or gas inside said cavity when said microbattery is activated.     conductors are connected to said anode and electron collector to guide the generated electron to an outside circuit.     said anode, said electron collector, said sealed liquid pocket, said breaking means, said pressing mean, etc are fabricated on a substrate.     said cavity between said anode and said electron collector has a porous or fibrous absorber to absorb said liquid mixture.     said liquid mixture consists of the sulfuric acid and hydrogen peroxide.     said liquid mixture includes KOH.        
 
         [0030]     Another preferred microbattery in combination consists of: a substrate; an anode supplying electrons when the anode contact to an electrolyte; a cathode; a sealed pocket including liquid electrolyte; a pressing means to generate pressure in said sealed pocket; a breaking means that is easily torn or removed by the pressure generated in said pocket; a cavity which said anode, said electron collector, and said breaking means contact to, where surface tension drives said liquid electrolyte into said cavity after tearing said breaking means, then electrochemical reaction occurs to activate the microbattery.  
         [0031]     In addition to this invention, the following in any combination may provide better microbattery. 
        conducting material is added to said cathode to reduce the internal resistance.     said cavity has at least one air holes to remove air or gas inside said cavity when said microbattery is activated.     a electron collector and conductor are connected to said anode and cathode to guide the generated electron to an outside circuit.     said anode, said cathode, said sealed pocket, said breaking means, said pressing mean, etc are fabricated on a substrate.     said cavity between said anode and said electron collector has a porous or fibrous absorber to absorb said liquid mixture.     said electrolyte is water.     said anode is magnesium and cathode is zinc chloride.        
 
         [0039]     Another preferred microbattery in combination consists of: a substrate; an anode supplying electrons when the anode contact to an electrolyte; a cathode; a solid electrolyte that can be melted when the solid electrolyte is heated up; a cavity in which said melted electrolyte can contact said anode and said cathode, where surface tension drives said melted electrolyte into said cavity after heating up, then electro-chemical reaction occurs to activate the microbattery.  
         [0040]     A system including at least one microbattery consists of: a substrate; an anode supplying electrons when the anode contact to an electrolyte; a cathode; a sealed pocket including liquid electrolyte; a pressing means to generate pressure in said sealed pocket; a breaking means that is easily torn or removed by the pressure generated in said pocket; a cavity which said anode, said electron collector, and said breaking means contact to, where the microbattery can supply electrical energy to said system after activation.  
         [0041]     In addition to this invention, the following in any combination may provide better system. 
        said electrolyte includes said cathode.     an area of said substrate has said microbattery, other area of said substrate has a diagnostic chip or system.     a side of said substrate has said microbattery, another side of said substrate has other part except said microbattery.     said diagnostic chip consists of a display part, a control part, and a diagnostic part which are activated by said microbattery.     said system has an input part such key pad to put data.     a memory part and a communication part are added to process the data and communicate with outside.     said system communicates with an outside system by using wireless transceiver.     said system has a needle to extract a test liquid or blood.     said system has a stopper to control the pricking depth.     there are a pair of saw teeth between the needle and a place facing the needle to preventing said needle from remaining on the skin when said system is taken out.     said system has a breaking means or a membrane, then said braking means is torn or removed when the skin is pricked with said needle to obtain blood or test liquid inside.     a soluble breaking means is inside said needle, said breaking means is removed to transport blood or test liquid inside.     said diagnostic part is vacuum, then blood or test liquid can be easily transport into inside by the pressure difference when said breaking means is removed.     in addition to said diagnostic part, said system has a prescription part to inject drug if needed.     said system has one more needle for injection of drug.        
 
         [0057]     A system includes: a substrate; an energy consuming part consisting of electrical components, MEMS device, etc on a side of said substrate; a power supplying part that generates electrical energy from an energy source such chemical and optical means, where energy generated from said power supplying part flows to said energy consuming part.  
         [0058]     In addition to this invention, the following in any combination may provide better system. 
        said power supplying part is battery converting chemical energy to electrical energy.     surface tension drives an electrolyte from a position to another position to activate the battery.     said electrolyte include a cathode material in it.     said anode, said cathode, and said electrolyte are stacked on a substrate.     said power supplying part is Zinc-Air battery to release electrical energy.        
 
         [0064]     A system consists of: an actuating means; a control means to control said actuating means; an energy supplying means to supply electrical energy to said actuating means and said control means, where an electro-chemical reaction in said energy supplying means occurs to supply electrical energy to said actuating means and said control means when an electrolyte is supplied.  
         [0065]     In addition to this invention, the following in any combination may provide better system. 
        said electrolyte is water or a liquid including water.     said electrolyte is an acid.     said system is drug delivery system in which an acid or water from human body activates energy supplying means to supply electrical energy to drug delivery device with said actuating mean, and said control means.       
 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0069]      FIGS. 1-1 ,  1 - 2 , and  1 - 3  show perspective view, side view, and working principle of a microbattery  101  embodying of the invention. In a perspective view  FIG. 1-1 , microbattery  101  consists of activation button  103  and several air hole  104  and  105  on a body  102 .  FIG. 1-2  is a side view of a microbattery along cross section A of  FIG. 1-1  to show the microbattery detail. The microbattery  101  consists of a upper plate  107  mounted on the substrate  106 , an activation button  103  on the upper plate  107 , a breaking means  108  such as a membrane placed between the upper plate  107  and the substrate  106  that is used to store an electrolyte  109  and is torn away when it is needed to break, a cavity  110  between the upper plate  107  and the substrate  106 , an electron collector  111  placed in the cavity  110  on the substrate  106 , an anode  113  supplying electrons after reaction to the electrolyte  109 , electrical conductors  112  and  114  for outside circuit to contact the electron collector  111  and the anode  113 , and air holes  104  and  105  on the upper plate  107  to remove the inside air in the cavity.  
         [0070]     Although several chemicals or materials are used for suitable operation, chemicals or materials are chosen at this time to give clear explanation. The substrate  106  is a silicon substrate; the electron collector  111  is thin gold layer that is usually used for electrical contact or pad in MEMS fabrication process. Zinc is selected for the anode  113 . The electrolyte  109  consists of a mixture of sulfuric acid and hydrogen peroxide. An electrolyte-resistant membrane such as plastic film is used as the activation button  103 .  
         [0071]     Using the microbattery just mentioned in  FIGS. 1-1  and  1 - 2 , working principle of a present microbattery is described in  FIG. 1-3 . The microbattery  101  has the sealed electrolyte  109  and zinc anode  113 , and thin gold layer  111  as electron collector. When electrical energy is needed, a user presses the activation button  103 , in turn, pressure in the electrolyte is generated, and finally the pressure breaks the membrane  108 . The surface tension of the electrolyte  109  drives the electrolyte into the cavity  110  while the air in the cavity goes out through the air holes  104  and  105 . After that, the electrolyte  109  can contact the zinc anode  113  and the thin gold layer as the electron collector  111  to give the following electro-chemical reactions of the microbattery. The electro-chemical reaction of the microbattery at the zinc can be expressed as the anodic reaction (oxidation): 
 
Zn+2H + +SO 4   − →Zn SO 4 +2e − +2H +   (1) 
 
 the cathodic reaction (reduction) is represented as: 
 
H 2 O 2 +2e − +2H + 2H 2 O   (2) 
 
 and the overall reaction is: 
 
Zn+H 2 SO 4 +H 2 O 2 →Zn SO 4 +2H 2 O   (3) 
 
 The electrons, generated from the zinc  113 , flows to hydrogen peroxide in the electrolyte through the conductor  114 , an outside circuit (not drawn in the figures), another conductor  112 , and electron collector  111 . It means that the zinc  113  is oxidized to supply electrons to the outside circuit and the hydrogen peroxide collects electron from the outside circuit. Therefore the microbattery  101  can supply electrical energy to circuits. The theoretical voltage of 2.5V is obtained but the measured voltage is 1.5. 
 
         [0072]     In the previous explanation, Zinc is selected as the anode  113 , the electrolyte  109  consists of sulfuric acid and hydrogen peroxide and gold layer is used as an electron collector. Generally, any liquid reacting to chemicals such as anode or cathode, several anode and cathode can be used for the microbattery of this invention. For example, ZnCl 2  solution for electrolyte, zinc as anode, and MnO 2  with carbon for cathode can be used for a microbattery.  
         [0073]     For long shelf life, chemical electrolyte is not suitable for microbattery because the encapsulated electrolyte maybe degrades or reacts to other material such as capsule or plastic material. For stable and safe microbattery, water can be used for water-activated microbattery. For example, the water-activated disposable microbattery consists of magnesium as the anode, cuprous chloride as the cathode, a cavity between the anode and cathode, and encapsulated water. This battery is stable and safe and has long shelf life because water is stable. When we press the encapsulated water, surface tension and pressure drive the water into the cavity for reaction and the electro-chemical occurs to supply electrical energy. Consider a rain-activated battery that consist of magnesium as the anode and cuprous chloride separated from the anode by a predetermined distance fabricated on a substrate. In this case, surface tension helps rain cover the anode and the cathode to generate electrical energy.  
         [0074]     Using  FIGS. 1-1 ,  1 - 2  and  1 - 3 , basic working principle of the invention was described. This microbattery structure has internal resistance. For small internal resistance, it is preferred to place a separator between anode and electron collector.  FIG. 2  shows an embodiment of the microbattery with a separator.  
         [0075]     The microbattery consists of a upper plate  207  mounted on the substrate  206 , an activation button  203  on the upper plate  207 , a breaking means  208  such as a membrane placed between the upper plate  207  and the substrate  206  that is used to store an electrolyte  209  and is torn away when it is needed to break, a cavity  210  between the upper plate  207  and the substrate  206 , stacked layers anode  213 /separator  216 /electron collector  211  between the upper plate  207  and the substrate  206 , electrical conductors  212  and  214  for outside circuit, and air holes  204  and  205 . The separator  216  has porous or fibrous structure that absorb easily electrolyte and avoid electrical short between the anode  213  and the electron collector  211 .  
         [0076]     As explained in  FIG. 1 , microbattery is described using thin gold layer as electron collector  211 , zinc as the anode  213 , sulfuric acid with hydrogen peroxide as electrolyte  209 .  
         [0077]     When electrical energy is needed, a user presses the activation button  203 , in turn, pressure in the electrolyte is generated, and finally the pressure breaks the membrane  208 . The electrolyte move into the cavity  210  and the separator  216  absorbs the electrolyte. After that, the electro-chemical reaction of Eq. 3 occurs to supply electrical energy.  
         [0078]      FIG. 3  shows another embodiment of the invention using a solid electrolyte. Heat-activated microbattery  300  consists of a upper plate  302  mounted on the substrate  301 , a cavity  310  between the substrate  301  and the upper plate  302 , an anode  307  and a cathode  309  and a solid electrolyte  306  in the cavity  310 , an electron collector  305  placed under the anode  307 , conductor  311  connected the electron collector  305 , another conductor  308  connected to the cathode  309 . The battery can be connected to an outside circuit via the conductors  311  and  308 .  
         [0079]     For convenient explanation, anode, solid electrolyte and cathode are selected the calcium, a molten eutectic mixture of LiCl—KCl, and K 2 Cr 2 O 7  are chosen in the case of  FIG. 3 . When the heat-activated microbattery  300  is heated up, the electrolyte  306  melts as shown  FIG. 4 . After that, the surface tension drive the melted electrolyte  312  to the anode  307  and the cathode  309 , and finally the battery supply electrical energy due to the electrochemical reaction.  
         [0080]      FIG. 5  shows a system  600  consisting of a microbattery, microchannels and an electrical circuit.  FIG. 6  is a cross section along B of  FIG. 5 . The microchannels can be used for biomedical device such as diagnostic device or DNA chip to test the blood or a test liquid. In  FIGS. 5 and 6 , the substrate  601  is a silicon substrate of the microbattery. A microbattery is placed on the front side of the substrate  601 , and an electrical circuits and microchannels are placed on the backside of the substrate  601 . The front side of the substrate has a electron collector  607 , anode  608 , an electrolyte (sometimes including cathode)  604 , an activation  603 , a membrane  605 , conductors  613 ,  606  connected to the electron collector  607  and anode  608  and a circuits  614 . The backside of the substrate has an electrical circuit  614  connected the conductor  613  and  606 , an lower plate  615  and microchannels  616  formed by space  617 .  611  and  612 , and  609  are air holes and a cavity, respectively.  
         [0081]     When a user presses the activation button  603 , the membrane  605  is broken. After that the surface tension drives the electrolyte  604  into the cavity  609 , and the electrolyte contact the anode  608  and the electron collector  607 . The generated electrons flow via the conductor  613  and  606  to supply electrical energy to the electrical circuit  614 . The electrical circuit  614  activates biosensor (not drawn in the figures) placed in the microchannel  616  to examine a test liquid (not drawn in the figures).  
         [0082]      FIG. 7  shows another embodiment of the invention. A diagnostic chip  700  consists of an inlet  702  for test liquid such as blood, a diagnostic part  701  having a diagnostic device or biosensor inside (not drawn in the figure), a microbattery activation button  706 , energy supplying part (microbattery)  705  with an air hole  707  and a display part  703  showing test result  704 . The inside of the diagnostic chip  700  may have signal-processing unit (not drawn in the figure) such as an electrical circuit.  FIG. 8  shows a signal flow of the inside of the diagnostic chip  700 . When the activation button  706  is pressed, energy supplying part  802  supplies electrical energy to a diagnostic part  801  and a display part  804  via a control part  803 . The diagnostic part tests a test liquid (not drawn in the figure) and sends a test result signal to the control part  803 , and the control part processes the signal of the test result from the diagnostic part. Finally the display part  804  displays the test result that the user recognizes. Liquid crystal display, light emitting diode, etc can be used for the display.  
         [0083]      FIG. 9  shows an improved embodiment of the invention of  FIG. 7 . The diagnostic chip  900  consists of diagnostic part  901 , an input means  905  such as key pads, an energy supplying part  902  with an activation button  903  and a display part  906  with a display means  907  such as LCD display.  
         [0084]      FIG. 10  describes a signal flow of the invention shown in  FIG. 9 . Pressing the activation button  903  activates the energy supplying part  1003  to supply electrical energy, then a diagnostic part  1001  examines a test liquid and send test signal to the control part  1005 , and finally the control part control the display part  1006  to display the test result. The input means  1007  can accept input of a user, and a memory part  1002  can offer memory required by the control part  1005 . The memory part  1002  can also used to store temporary data during signal processing. A transmitting part  1004  can send a processed signal offered from the control part to an outside unit (not drawn in the figure) such as a computer. The transmitting part can be connected to outside by a conducting wire or an optical fiber. Wireless transmitting part can also be used to send the signal via the electromagnetic wave, the light and the ultrasonic wave. If needed, the signal for communication can be modulated or demodulated.  
         [0085]      FIGS. 11-1 ,  11 - 2  and  11 - 3  shows drawings of diagnostic part  1101  of an embodiment of the invention that easily accepts the test liquid such as blood in  FIG. 9 . In this Figures, the diagnostic part has a needle  1102  for the test liquid. The needle may have a stopper  1103  that allows the needle  1102  to penetrate into the skin by a predetermined depth. In  FIG. 11-2 , the diagnostic part  1101  consists of a cavity  1108 , a diagnostic mean  1109  which is adjacent to the cavity  1108 , a needle  1102 , and a stopper  1103  fixed on the needle  1102 . The needle  1102  is connected to a cap  1106  via a guide  1104 , and the cap has a path  1105  that can guide the needle  1102 . There is a breaking means  1107  such as a membrane at the end of the cap  1106 .  
         [0086]     Only explanation for getting blood is given here because diagnose or test is same as shown in  FIG. 9  after getting blood. The human skin is pricked with the needle  1102 , then the stopper  1103  on the needle is pressed by the skin, after that the needle  1102  move into inside along the guide  1104  and the path  1105 , finally the breaking means  1107  is torn as shown in  FIG. 11-3 . The blood of body can flow to the diagnostic means  1109  via the needle  1102 . The cavity  1108  may be at the atmospheric pressure or vacuum to assist the blood flow.  
         [0087]     The embodiment of  FIG. 11-2  has a potential problem; the needle  1102  maybe remain on the skin when the diagnostic part is taken out from the skin. In order to resolve this problem,  FIG. 12  is presented describing the enlarged view of needle using saw teeth. When the skin is pricked with the needle  1102 , the needle  1101  moves in the right direction ( 1205 ). The moved needle is prevented from moving in the left direction when it is taken out from the skin. The  1204  indicates the support of the saw teeth  1203 .  
         [0088]      FIG. 13  shows an embodiment of the invention where the breaking means  1302  is in a needle  1301 . The needle  1301  fixed by a stopper  1303  has a soluble breaking means  1302 . The stopper  1303  is connected to a cap  1304 , the cap  1304  is connected to a diagnostic part  1305  that consists of a cavity  1307  and a diagnostic means  1306 . When the human skin is pricked with the needle  1301 , a chemical (for example water) in blood reacts to the breaking means  1302  and finally the blood can be transport from the human body to the cavity  1307  to supply blood to the diagnostic means  1306 .  
         [0089]      FIG. 14  shows an embodiment of the invention that has a different diagnostic part. A needle  1401  has a breaking  1402  inside the needle  1401 , the needle  1401  is connected directly to a diagnostic means  1404 , where there are the diagnostic means  1404  and a cavity  1406  in the diagnostic part  1405 . To get easily blood, the cavity  1406  keeps vacuum. The diagnostic means  1406  is connected from the needle  1401  to the vacuum cavity  1406  via channel or tube (not drawn in the figure). When the human skin is pricked with the needle  1401 , the breaking means  1402  is removed by chemical reaction to supply blood into the diagnostic means  1404 . The vacuum of the cavity  1406  helps the blood to flow into the diagnostic  1404 .  
         [0090]     In  FIGS. 11, 12 ,  13 , and  14 , only one needle was used to get blood from the human body.  FIG. 15  is an embodiment of the invention that has another needle for a drug injection. In  FIG. 15 , a diagnostic and prescription part  1500  has an inspection needle  1502  and prescription needle  1503  connected to a diagnostic means  1501 . Blood coming from the inspection needle  1502  is examined by an inspection means (not drawn in the figure) in the diagnostic and prescription part  1500 . If needed, a drug can be supplied to the human body via the prescription needle  1503 .  
         [0091]      FIG. 16  shows an embodiment of the invention that is a stacked microbattery on the backside of a substrate of a diagnostic means  1600 . The microbattery consists of a electron collector  1602  on the substrate  1601 , an anode  1603 , a separator  1604 , cathode  1605  that absorbs an electrolyte, another electron collector  1606 , and an insulation cap  1607 . Working principle is similar to that of microbatteries already mentioned in this invention. If the battery  1600  is connected to a outside circuit (not drawn in the figure) via the electron collector  1602  and  1606 , the electrolyte absorbed by the cathode  1605  flows to separator  1604  and reacts to the anode  1603  to supply electrons to the electron collector  1602 . The supplied electron flows through the outside circuit to another electron collector  1606  and finally reacts to the cathode  1605 . For a detail example, the microbattery can consist of zinc as the anode, cellophane film as separator, MnO 2  as cathode, zinc chloride as an electrolyte that is absorbed in the cathode. For more conductivity, carbon power can be added to the cathode.  
         [0092]     To construct on the backside of the diagnostic chip, zinc-air battery can be used where electrical energy is generated when the zinc contacts air.  
         [0093]      FIG. 17-1  shows an embodiment of the invention that is a drug delivery system  1700  activated by microbattery.  FIG. 11-2  is a cross section of the drug delivery system of  FIG. 11-1 . The drug delivery system  1700  consists of a porous or fibrous material  1701  on the outside of the system, a drug delivery mean  1702 , a microbattery  1703  already explained in this invention, and a control part  1704  to operate the drug delivery means  1702  if needed. The microbattery  1703  have no electrolyte at this time. After removing a protective layer (not drawn in the figure) such as plastic layer for protection, a person swallows the drug delivery system  1700  to deliver a drug to the body. The microbattery inside is activated by water or acid through the porous material  1701 , in turn, activating the drug delivery system by supplying electrical energy to the control part  1704  and the drug delivery means  1702 . In this case, the water-activated microbattery uses magnesium as the anode, silver chloride as the cathode. This battery is activated by water as the electrolyte that is in our body.  
         [0094]     So far, several embodiments and details for the invention are explained. The invention includes embodiments that can be easily obtained from simple modification and combination of embodiments of the invention already shown. If a person understands this invention, he or she easily change anode, electrolyte, cathode, etc. For example, a water-activated microbattery consists of magnesium as the anode, and copper chloride or PbCl 2  as the cathode. This case is included in the present invention. Bigger battery using the same principle is also included in the invention. Placing a droplet of blood or water-including liquid on a diagnostic chip can also activate the microbattery of the invention and a system connected to the battery at the same time.  
       ADVANTAGE OF THE INVENTION  
       [0095]     If a battery is needed, pressing the activation button releases the sealed water or electrolyte to react to chemical such as anode, in turn, activating the microbattery of the invention. On a same substrate, microbattery, MEMS devices such as microchannels and electrical circuit can be fabricated. It means that the microbattery may be cheap and area-effective. The fabrication cost may be reduced because the microbattery and MEMS devices can be fabricated on a substrate at the same time. In this case, semiconductor technology such as CMOS process can be directly used to fabricate the microbattery, electrical circuit, MEMS devices on a substrate.