This invention relates to a diagnostic system for the internal status of a lithium battery. More specifically, it relates to a diagnostic system having a plurality of sensor units for detecting the internal status of a lithium battery. It has the advantages and functions of real time monitoring, the enhancement of utilization safety, and the extension of product life.
Generally, when a Li-ion (lithium-lion) battery works under high power and fast charging or discharging, its internal temperature will rise rapidly. Then, Li ions will over-react to cause a great safety threat.
Furthermore, when the Li-ion battery is charging and discharging, the Li metal precipitated during the charging process will form a new active surface and react with the solvent of the electrolytic solution. Then, the internal impedance of the battery will rise. The discharging efficiency will be decreased. As the charging frequency increases, the battery capacity will decrease gradually. Hence, the Li metal precipitation process in the charging process will deteriorate the battery characteristics or even cause safety problems.
During fast charging and discharging process, the precipitated Li metal will form needle-like and twig-like crystal, which could cause many problems in the battery. Since the Li metal that forms needle-like or twig-like crystal has very large surface area, the occurrence probability of secondary reaction will be increased. The current efficiency will be lowered in accelerated way. When needle-like or twig-like crystalline Li metal penetrates isolation film, it will even cause short circuit between the positive and negative electrode. That will cause self-discharging of the battery. Such battery cannot be used. In the serious case, heat will be generated within the battery, or even explosion will occur.
During the re-charging process of Li-ion battery, the precipitation process of Li metal will increase. That will affect the penetration rate of Li ion and isolation film. Meanwhile, repeated charging and discharging will happen. Then, voltage and current will drop. Impedance will rise. Capacitance will drop. Finally, such over-charging will turn voltage and current unstable. That will cause safety problem eventually.
Therefore, it can be seen that during the charging and discharging process of Li ion battery, any abnormal change in temperature, voltage, and current is possible to cause utilization danger. Moreover, general Li ion battery does not have any internal test function. That is, during Li ion battery charging and discharging process, the user cannot know any abnormal change about internal temperature, voltage, and current. Thus, this might lead to the occurrence of accident.
In addition, the rise in voltage and temperature will lead the electrolytic solution generating gaseous CO2. It would have certain danger if CO2 is too much (it might eventually catch fire). Further, for a general lithium battery, no pressure sensor is installed. The user cannot know the situation of the gas inside the battery. Thus, it has certain degree of danger in utilization.
Therefore, it is needed to develop a new product to solve the above mentioned drawbacks and problems.
The objective of the present invention is to provide a diagnostic system for the internal status of a lithium battery, which has advantages and functions such as: real time monitoring, the enhancement of utilization safety and the extension of utilization life, etc. This invention is to solve the incapability of internal monitoring and the subsequent safety problems caused in the prior art.
The technical means for solving the above mentioned problems in the present invention is to provide a diagnostic system for the internal status of a lithium battery comprising:
a lithium battery unit including a battery shell body and a lithium battery, the battery shell body having an internal surface and an internal space, the lithium battery being installed at the internal space of the battery shell body;
a plurality of sensor units, each sensor unit having an electrically conductive wire and at least a sensor part, the electrically conductive wire including a buried section and an exposed section, the buried section being installed between the internal surface of the battery shell body and the lithium battery, the exposed section being extending to an external side of the battery shell body; the sensor part being installed on the buried section so as to detect status of the lithium battery; and
a control system for connecting to the exposed section of the electrically conductive wire so as to receive data measured by the sensor part for knowing a situation of the lithium battery.
Referring to
With regard to this lithium battery unit 20, it includes a battery shell body 21 and a lithium battery 22. The battery shell body 21 has an internal surface 211 and an internal space 212. Furthermore, the lithium battery 22 is installed at the internal space 212 of the battery shell body 21.
About these sensor units 30, each sensor unit 30 has an electrically conductive wire 31 and at least a sensor part 32. The electrically conductive wire 31 includes a buried section 311 and an exposed section 312. The buried section 311 is installed between the internal surface 211 of the battery shell body 21 and the lithium battery 22. The exposed section 312 extends to an external side of the battery shell body 21. The sensor part 32 is installed on the buried section 311 so as to detect the status of the lithium battery 22.
Concerning this control system 40, it is used for connecting to the exposed section 312 of the electrically conductive wire 31 so as to receive data (or signals) measured by the sensor part 32, and the user can know the situation of the lithium battery 22.
Furthermore, each sensor part 32 can measure the temperature, voltage value and current value where it is located. Based on the detection of these sensor parts 32, the change in charging and discharging process of each location of the lithium battery 22 is monitored in real time. Hence, when any abnormal change is occurred in the lithium battery 22, a safety protection action can be taken immediately to avoid the occurrence of accident (For example, it is used to detect a lithium battery installed on the electric vehicle that needs to charge or discharge frequently). The importance of temperature, voltage and current for the lithium battery 22 is described as follows.
[1] Temperature detection: Under high power as well as fast charging and discharging, the internal temperature of Li-ion battery will rise rapidly. The over-reaction of Li ion will cause a great safety threat. Moreover, the sensor part 32 of the present invention can make real time monitoring on the temperature of the lithium battery 22. When any abnormal change occurs, a necessary protection action can be done immediately at the time of occurrence so as to enhance its safety (For example, when the battery is overheated, the charging and discharging of the battery can be stopped immediately).
[2] Voltage and current detection: During the fast charging and discharging process of Li-ion battery, the precipitated Li metal will form needle-like and twig-like crystal, which will cause many problems in the battery. Since the surface area of formed needle-like and twig-like crystal of Li metal is very large, the occurrence probability of electrochemical reaction will be increased. Also, it will lower the current efficiency. Moreover, when an isolation film is penetrated by needle-like or twig-like crystal of Li metal, short circuit could happen between the positive and negative electrodes. Eventually, self-discharging of the battery will occur. This battery becomes useless. In the serious case, heat generation or even explosion are possible. During the repeated charging process of Li-ion battery, Li metal precipitation reaction will be increased, and the penetration rate of Li ion and isolation film will then be affected. At this moment, repeated charging and discharging will lower the voltage and current, raise the impedance, and lower the capacitance. Such over-charging will make voltage and current unstable. Finally, it will cause safety problems. Therefore, monitoring of voltage and current is needed.
Before monitoring this invention, the user can calculate the normal and safe range of the temperature, voltage and current of each location of the lithium battery 22. When the change of the temperature, voltage or current of the lithium battery 22 exceeds a normal range, the user can know it immediately and then can take necessary protection actions. In addition, if appropriate improvement is made when abnormal change occurs at each part of the lithium battery 22, the harm to the lithium battery can be reduced. Also, the product life can be prolonged. For the sensor part 32, not only it can detect the temperature, voltage, and current where it is located; but also it can detect the pressure it is located. By utilizing the pressure detection, when the lithium battery 22 generates CO2, the sensor part 32 can know the quantity of CO2. When the pressure in the lithium battery 22 exceeds the preset normal safe range, it can be known immediately and necessary protection actions can be taken.
Of course, in real application, the arrangement of the sensor unit 30, the installation of the sensor part 32 on the buried section 311 and the quantity of the sensor part 32 can be modified depending upon the shape and volume, volume size, and location that needs to be detected of the lithium battery 22. For the first embodiment as shown in
In addition, as shown in
Therefore, the advantages and functions of the present invention can be summarized as follows:
[1] Real time monitoring can be achieved. In the existing lithium battery, there is no detection function of temperature, voltage, current and pressure, and the internal change of lithium battery. So, nobody knows the internal status of the lithium battery. However, about the present invention, a plurality of sensor parts 32 are installed between the internal surface 211 of the battery shell body 21 and the lithium battery 22. Thus, the change in each part can be detected accurately and transmitted to the control system 40. Hence, the objective of real time monitoring can be achieved.
[2] The utilization safety can be enhanced. In the existing lithium battery, there is no detection function of temperature, voltage, current and pressure, and the internal change of lithium battery. Under this condition, danger could happen due to overheating, too much gas, and the instability in voltage or current. However, the present invention has the function of real time detection. When any abnormal change occurred in the lithium battery 22, it can be known immediately. Appropriate actions can be taken to avoid the occurrence of accident. Hence, it has the advantages of enhancing the utilization safety.
[3] It can prolong the product life. In the past, it cannot detect the change in each part inside a lithium battery. Therefore, no immediate improvement can be made. Accordingly, the product life of the lithium battery will be affected. However, for the present invention, the change of each part of the lithium battery 22 can be monitored in real time, and appropriate improvement can be made. The danger about the lithium battery 22 can be reduced. Of course, the product life can be prolonged.
The above is only description of better embodiment of the present invention, and any simple modification and change of the embodiment should be within the scope of what is claimed.