What is the relationship between lithium battery energy density and size specifications

The following is the actual lithium battery model to explain the relationship between battery energy density and size: lithium battery model: 523450A1000mAh lithium drill material battery thickness 5.2mm, battery width 34mm, battery height 50mm. Lithium battery first step: List the relevant fixed parameters. Lithium battery anode gram capacity: 142mAh/g; anode gram capacity: 330mAh/g; anode compaction density: 3.8g/cm3; anode compaction density: 1.55g/cm3 ; Positive lithium sulphate ratio: 94% Negative graphite powder ratio 94% Separator thickness: 0.016; Tab width: 4mm; For a lithium battery system, some parameters are fixed, and only need to be inserted in the design. ! Step 2: Carrying out the battery design journey 1. Small battery, one core, then the maximum thickness of core: u003d battery thickness-shell thickness u003d 5.2-0.2*2 u003d 4.8mm (generally the thickness of the aluminum shell is 0.2-0.3, It may be different in different places, but it is not relevant) 2. The height of the core, except for the top cover 1mm, the bottom cover 0.5mm, the plastic spacer 1.5mm, and the reserved space 1mm, then the core height u003d 50-1-0.5-1.5 -1u003d46mm In other words, the diaphragm can be 44mm wide. Generally, if we make an aluminum case, we may choose a 20um diaphragm. If we make a large battery, the diaphragm may be thicker, ranging from 25um to 35um. 3. The width of the negative electrode. The negative electrode must be narrower than the separator. It can be 1mm or 2mm, depending on how you keep it. Assuming 2mm here, then the width of the negative electrode is 42mm. (When making some large-size batteries, you can appropriately widen 3-4mm) 4. The negative electrode wraps the positive electrode, then the positive electrode is narrower than the negative electrode, 1-3mm, because it is a small battery, we choose 1mm, and the width of the positive electrodeu003d44-1u003d43mm . 5. In accordance with relevant experience, suppose the double-sided density of the positive electrode u003d 40.5mg/cm2, the gram capacity of the positive electrode is 140mAh/g, and the proportion of active material is 94%; the gram capacity of the negative electrode is 320mAh/g and the proportion of active material is 94%. Safety factor u003d 1.03 (can be higher, 1.1) then we can calculate: negative electrode double-sided density u003d 40.5*140*94%/(320*94%) 1.05u003d18.45mg/cm26, positive electrode material can be pressed to 3.8g /cm3; negative electrode can achieve 1.6g/cm3; aluminum foil 12um, copper foil 12um. 7. Then the thickness of the positive and negative electrodes can be calculated: the thickness of the positive electrode is 40.5/3.8*10+16u003d119um, the thickness of the negative electrode is 18.45/1.6+10u003d127um; Layer thickness u003d thickness of positive electrode + thickness of negative electrode + thickness of 2 layers of separator u003d 119+127+16*2u003d278um, 9. Visible, total winding number u003d core thickness/(single layer thickness*2)u003d4.8*90% / (278/1000) u003d 15.5 turns, rounded: that is, the negative electrode has 15 folds, and the positive electrode has 16 folds (90% is the reserved space for the thickness of the battery, and the thickness value is different, depending on the thickness of the material rebound) 10. Calculate the size of the coiled needle, the width of the coiled needle u003d the width of the core-the thickness of the core-2 u003d (34-0.20*2) -4.8) * 92% u003d 27mm 11. Calculate the length of the positive electrode: the length of the positive electrode u003d (number of layers-2 )*Double winding thickness + winding needle width + winding needle thickness + one layer winding thickness + winding needle width) * (number of layers-1)/2+ winding needle width-thickness/2u003d((16-2) *0..278*2+(27+27+0.5+0.262))*(16-1)/2+27-5.2/2u003d505mm, when the test paper, fine-tune the size. Calculate the length of the negative electrode: negative electrode u003d positive electrode length-needle width-tail scraping position -1012, tab width and thickness, small batteries, tab tab 0.1*4mm is basically enough 13, pole piece scraping position: Au003d10Bu003droll Needle width*2.7+3Cu003dD+4*2Du003d electrode width+(2～4) Eu003drolling needle-C/214, calculation capacity: design capacityu003dpositive electrode dressing amount*g capacity*active material ratiou003d*140mAh /g*7.516*94%u003d1052mAh15, Nominal capacity: In general design, the design capacity is about 1.05% of the nominal capacity. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete it. One: Comparison of the advantages and disadvantages of lead-acid batteries and lithium batteries