Switching with a relay
The battery is connected to the normally closed point of the relay, and the external power supply is connected to the normally open point of the relay
Using an external power supply to power the relay. When there is an external power supply. Then the normally closed point of the relay is triggered and the normally open point is combined.
In this way, the normally closed point is triggered and the battery is turned off, and the normally open point is combined with the external power supply to start supplying power. If the external power is turned off, the relay is normally closed due to a power failure. Clicking reset will return the battery. power supply
The switching frequency of the relays is necessary to avoid short-term interruption of the power supply
(The UPS computer also supplies power in this way)
First of From a point of viewstructural, the full name of lithium polymer battery should be lithium ion polymer battery. From this point of view, lithium polymer battery is actually a type of lithium ion battery. But the biggest difference between the two is the electrolyte used inside. Lithium-ion batteries use liquid electrolytes, while lithium-ion polymer batteries use solid polymer electrolytes instead. This polymer can be solid or semi-solid (colloidal).
Second, in terms of appearance, most mobile power supplies currently on the market use cylindrical lithium-ion batteries (that is, 18650) or lithium-polymer batteries shaped like block. Therefore, when we choose a mobile power supply, if the outer packaging of the product does not specifically indicate the type of battery cells used, we can just get a rough idea of the type of battery used atinside the product thanks to the thickness of the product itself.
It can be said that after years of development, lithium-ion battery technology has become relatively mature, and mass production has made its manufacturing cost very low. Therefore, lithium-ion batteries have more price advantages than lithium-polymer batteries. This is why most laptops and other devices currently use this type of battery cell.
Since lithium ions using liquid electrolytes will suddenly increase their internal pressure when overcharged (overcharging), in order to avoid the explosion of the sealed metal case, this 18650 battery is generally equipped with a security system. Valve on the top When the internal pressure of the battery is too high, the safety valve on the top will automatically pop up to reduce the pressure. However, when the safety valveurity opens, lithium ions escaping from the battery may still catch fire due to contact with oxygen in the air.
Compared to lithium-ion batteries using liquid electrolytes, lithium polymer batteries using solid polymer electrolytes are ultra-thin in shape, with a theoretical minimum thickness of up to 0.5 mm, and any arbitrary shape and area. It greatly improves the flexibility of the battery shape, so that it can be better transformed into a new generation of lithium batteries of any shape and capacity.
Therefore, for electronic products using this type of lithium-ion battery cells, there are very high requirements for their internal charge and discharge protection integrated circuits. However, with the years of development of lithium-ion batteries, both the design of the battery itself and the ntechnical level of various integrated protection circuits have become very mature. As long as we can do it well in daily use, the 18650 battery is very safe to use and avoids the battery being pierced by hard objects, otherwise most laptops on the market would not use this type of battery.
Strictly speaking, the positive electrode, negative electrode, electrolyte and working principle of lithium polymer batteries are the same as those of lithium ion batteries using liquid electrolytes. The only difference is the separator and packaging materials. Therefore, basically lithium polymer batteries are also a type of lithium ion batteries.
Summary: In fact, whether it is a steel case lithium ion battery or a soft pack lithium ion battery, the safety performance is very good . After all, the procurrent production. Lithium-ion battery technology is very mature. As long as it avoids high temperature, short circuit, overload, puncture, etc. in daily use, so-called “explosion”, fire and other unexpected situations can be avoided. As for the lithium-ion batteries and lithium-polymer batteries that we often talk about, both have their own advantages and disadvantages. If you prefer the cost-effectiveness of the product, choose the 18650 battery. If you prefer the appearance and size of the product. mobile power, then the slightly more expensive lithium polymer battery is the first choice.