WHAT IS HALF-CUT OR HALF-CELL TECHNIQUE? (PART 1)

1. WHAT IS HALF-CUT OR HALF-CELL?

Half-Cell is the traditional method of cutting cell into two equal parts through laser beam. This technique helps to increase a fraction of the performance compared to traditional battery. The cells connecting together make up a complete battery.

2. OUTSTANDING DIFFERENCE:

Reduce the loss of the PV panel.
On the surface of the PV panel, we can see the shiny streaks of metal. These are called Busbar. Busbar has the mission to lead the electron collected from the cells to the Junction box.

Because the Busbar itself survives resistance, the current running on the Busbars will cause the loss. The cell-cutting helps the current running on the Busbars decrease by half.

According to the depreciation formula: P = I2 x R. When I halves, it will help reduce the loss 4 times.
Notes:
P is the Power
I is the current intensity
R is resistance.

This helps the battery power increase by about 3% compared to the traditional battery.
Example: battery can increase the performance from 19% to 19.57%. In terms of voltage, the capacity increases from 390 to 401.7 Wp.

3. DEEPER ANALYSIS OF PV PANEL
For example, the battery includes 60 cells (V = 0.5 V) in serial connection. According to this kind of connection, the battery will have a voltage of 30V.

The cell is divided into 3 strings. Meanwhile, with the half-cell, it will be 6 strings.
If the half-cell are connected similarly to the old scheme, the voltage of the battery will be doubled and the current will be halved.

Thus in order to help half-cell battery function similarly to normal battery, they need to be divided into two groups, each of which includes 60 cells.
These two groups will be in parallel. As a result, the voltage will return to 30V.

More optimal operational ability when shaded

The cells of the PV panel are usually in serial connection. According to this principle, a shaded cell will cause the battery to suffer deterioration of power.

Hence the manufacturer divides the serial-connection cells into 3 lines and uses 3 diodes to separate the shaded cell line. The remaining lines will not be affected.

If a cell is shaded, the capacity of the battery reduces only by 1/3. With half-cell battery, because the cells are cut in half, the total amount will reach 120 cells.

When connected and put into 6 lines, 1 cell shaded will only cause 1/6 reduction of capacity.

An interesting fact is that there are not many differences between the manufacturing processes.

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