Solar street lamps have now become the main facilities for the lighting of urban and rural roads. They are simple to install and do not need a lot of wiring. By converting light energy into electric energy, and then converting electric energy into light energy, they bring a piece of brightness for the night. Among them, rechargeable and discharged batteries play a key role.
Compared with the lead-acid battery or gel battery in the past, the lithium battery commonly used now is better in terms of specific energy and specific power, and it is easier to realize fast charging and deep discharge, and its life is also longer, so it also brings us a better lamp experience.
However, there are differences between good and bad lithium batteries. Today, we will start with their packaging form to see what the characteristics of these lithium batteries are and which one is better. The packaging form often includes cylindrical winding, square stacking and square winding.
1. Cylindrical winding type
That is, cylindrical battery, which is a classical battery configuration. The monomer is mainly composed of positive and negative electrodes, diaphragms, positive and negative collectors, safety valves, overcurrent protection devices, insulating parts and shells. In the early stage of the shell, there were many steel shells, and now there are many aluminum shells as raw materials.
According to the size, the current battery mainly includes 18650, 14650, 21700 and other models. Among them, 18650 is the most common and the most mature one.
2. Square winding type
This single battery body is mainly composed of the top cover, shell, positive plate, negative plate, diaphragm lamination or winding, insulation, safety components, etc., and is designed with needle safety protection device (NSD) and overcharge safety protection device (OSD). The shell is also mainly steel shell in the early stage, and now aluminum shell has become the mainstream.
3. Square stacked
That is, the soft pack battery we often talk about. The basic structure of this battery is similar to the above two types of batteries, which are composed of positive and negative electrodes, diaphragm, insulating material, positive and negative electrode lug and shell. However, unlike the winding type, which is formed by winding single positive and negative plates, the laminated type battery is formed by laminating multiple layers of electrode plates.
The shell is mainly aluminum plastic film. The outermost layer of this material structure is nylon layer, the middle layer is aluminum foil, the inner layer is heat seal layer, and each layer is bonded with adhesive. This material has good ductility, flexibility and mechanical strength, and also has excellent barrier and heat seal performance, and is also very resistant to electrolytic solution and strong acid corrosion.
In short
1) Cylindrical battery (cylindrical winding type) is generally made of steel shell and aluminum shell. Mature technology, small size, flexible grouping, low cost, mature technology and good consistency; The heat dissipation after grouping is poor in design, heavy in weight and low in specific energy.
2) Square battery (square winding type), most of which were steel shells in the early stage, and now are aluminum shells. Good heat dissipation, easy design in groups, good reliability, high safety, including explosion-proof valve, high hardness; It is one of the mainstream technical routes with high cost, multiple models and difficult to unify the technological level.
3) Soft pack battery (square laminated type), with aluminum-plastic film as the outer package, is flexible in size change, high in specific energy, light in weight and low in internal resistance; The mechanical strength is relatively poor, the sealing process is difficult, the group structure is complex, the heat dissipation is not well designed, there is no explosion-proof device, it is easy to leak, the consistency is poor, and the cost is high.
Post time: Feb-10-2023
