Coiled Lithium Battery
A battery composed of cells that are assembled and formed in a coiled manner is called a coiled battery. Coiled batteries are also called cells, and are referred to as rolled cells by the battery industry.
Laminated Battery
Power battery is generally divided into three forms: square shell, soft pack and cylindrical, mostly using two processes: coiled and laminated, each with different advantages and disadvantages, laminated battery is the use of laminated lithium batteries for vehicles.
The laminated battery and the traditional electric car lithium-ion battery operating principle is common, the internal by the positive electrode, negative electrode, barrier, electrolyte composition, the use of lithium ions to move the electricity.
Coiled lithium battery and laminated lithium battery which is good
1, the battery discharge channel comparison
Coiled lithium battery discharge channel is slightly lower. Because of the high internal resistance polarization, part of the voltage is consumed in the internal polarization of the battery, so the discharge channel is slightly lower.
Stacked lithium battery discharge channel is high. Lower internal resistance polarization is smaller, so the discharge channel will be higher than that of coiled cells and closer to the discharge channel of the material itself.
For many electric devices with high discharge cut-off voltage, the higher discharge channel of the laminated battery is undoubtedly the preferred choice.
2, battery capacity density comparison
Coiled lithium battery capacity density is slightly lower. Because of the thickness of the pole lug, the two ends of the cell are round, the two layers of the closing barrier to occupy the thickness for nothing and other reasons resulting in the internal space is not fully used, the volume than the capacity is slightly lower.
Stacked lithium battery capacity density is higher. The internal space of the cell is fully used, so the volume to capacity is higher compared to the winding process.
The difference in battery capacity is reflected in the thicker (coiled side space is not fully used will be expanded) and thinner (coiled lug thickness occupies the thickness of space for nothing will be expanded) of these two types of batteries, and on the general practice scale battery, the difference exists, but will not be particularly significant.
3, battery energy density comparison
Coiled lithium battery energy density is slightly lower. Because of the lower volume than the capacity and discharge channel is lower for these two reasons, resulting in energy density is not as good as the laminated process battery.
Stacked lithium battery energy density is high. The discharge channel and volumetric capacity are higher than those of coiled cells, so the energy density is also higher.
For details, please refer to the expansion channel and capacity density of the two points, in general, the stacked sheet is superior.
4, the applicable thickness of the battery comparison
Coiled lithium batteries are narrower in scale. On ultra-thin batteries, the thickness of the pole lug occupies too much space share will then affect the battery capacity. On the ultra-thick battery, not only winding up the pole piece is too long to manipulate, and the space on both sides of the battery can not be fully used, will also reduce the battery capacity.
Stacked lithium batteries have a wide range of applications. Whether it is made into ultra-thin batteries or ultra-thick batteries, the stacking process can serve.
Winding battery in the ultra-thin ultra-thick battery has no advantage, but also note that ultra-thin battery is not used for the time being, ultra-thick battery can be completed by two thinner battery stacked in parallel (but to reduce the value of a certain capacity).
5, battery thickness control comparison
Coiled lithium battery thickness is difficult to manipulate. Because the internal structure of the cell is not uniform, the pole lug, the end of the barrier, the two ends of the cell is a simple ultra-thick orientation.
The thickness of stacked lithium battery is easy to control. The internal structure of the cell is common, and the thickness of each part of the battery is also common, so it is easy to control the thickness.
Because the thickness of coiled lithium battery is difficult to manipulate, so the planning had to leave some extra margin in the thickness, and then decreased the planning capacity of the battery.
6, battery thickness deformation comparison
Coiled lithium batteries are slightly deformed. Because the internal structure is not uniform, the charge and discharge of the internal reactions of the cell degree, the rate is not uniform. Therefore, for thicker coiled batteries, after charging and discharging at large rates or after repeated cycles, there may be deformation.
The laminated lithium battery is not easily deformed. The internal structure is uniform and the reaction rate is relatively high. Even thick cells are not easily deformed.
This is also a reason why coiled batteries are not suitable to do a great deal of thickness.
7, battery shape comparison
Coiled lithium battery shape single; can only be made into a rectangular battery. Laminated lithium battery scale sensitive. According to the scale of the battery to plan the scale of each pole piece, and then the battery can be made into arbitrary shape.
Sensitive scale is a significant advantage of the laminated process, but as far as the market is concerned, it seems that the demand for shaped batteries is not very large.
8, battery suitable for field comparison
Coiled lithium batteries only do the customary battery. Stacked lithium batteries do high rate batteries, shaped batteries, power batteries.
Because the laminated sheet process multiplier function is better, the appearance of the shape of the selection is more diverse, so the applicable scale is also wider than the winding battery.
9, battery coating comparison
Coiled lithium battery coating requirements are high. For each pole, each part of the coating film density can not be significantly different, need to strictly control the film density.
Laminated lithium battery coating requirements are low. Because the positive and negative electrodes are divided into many small pieces, the impact of poor coating film density can be excluded by staging the small pieces before stacking.
Because of the improvement of the process now, the winding battery very long pole film density manipulation in a small error scale has not been difficult, and each small piece of the stacked battery will be weighed and graded very tedious, so the point of the impact on the two is not really large.
10, slitting
Coiled lithium battery slitting convenience, high qualification rate. Each cell only needs to be cut once for each positive and negative electrode, with little difficulty and low probability of defective products.
Stacked lithium battery slitting tedious, low pass rate. Each cell has dozens of small pieces, each small piece has four cutting surfaces, and the slicing process is prone to bad punching, so for a single cell, the probability of broken surface and burr of the pole piece is greatly increased.
Although the fire can be cut after the screening to the stacked battery of small pole piece strict control, but easily hundreds of thousands of small pole piece, who will have time to check one by one?
11, the elasticity of the battery pole piece
Winding lithium battery poles need to have some flexibility. To avoid cracking at the bend, drop material. |Stacked lithium battery cells can be no elasticity.
As long as the pole sheet ingredients coating is not significantly out of the question, the general pole sheet is able to buy enough to meet this condition.
12, battery spot welding
Coiled lithium battery spot welding is simple. Each battery only needs to spot weld two places, easy to control.
Stacked lithium batteries are slightly false welding. All the pole pieces are spot welded to a solder joint, difficult to operate and slightly false welding.
Small batch production of false welding is not difficult to control, but the large production, false welding is difficult to monitor and useful solution.
13, battery production control
Coiled lithium battery production control is relatively simple. A battery with two poles, easy to control. Stacked lithium battery production control is more cumbersome. Each battery has dozens of pole pieces, detection, transfer, statistics, etc. are difficult.
For a small-scale factory, a daily production of tens of thousands means a million stacked pole pieces per day! Production of hundreds of thousands of words or perhaps even nearly ten million small pole pieces! The production process of turnover, monitoring the difficulty can be imagined.
14、Operator requirements
Li-ion battery winding operator requirements are low. Want to be skilled to complete the winding is difficult, but want to be qualified to complete the winding is not difficult. Know the process and control the alignment of the pole piece can be started.
Stacked lithium batteries require high operator requirements. Stacking operation is difficult, and the negative piece of the positive piece of the over-length, over-width planning is generally not too large, so the operator needs to have a certain level of operation.
15、The threshold of entry into the battery
The threshold for winding lithium batteries is low. Manual winding is a simple operation, when the lack of funds can be considered manual operation, eliminating the need to purchase large active equipment, reducing the threshold of entry.
Stacked lithium batteries have a high threshold for entry into the industry. Active equipment is not yet sophisticated, manual operation of the laminating process is cumbersome, resulting in rising labor costs, thus raising the threshold of the laminating process battery.
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