The present invention relates to solar energy - based mini
charger for low power applications. More particularly, the
present invention relates to solar charger for mobile phones.
BACKGR0UND OF THE INVENTION
As per the prior art, the solar mobile phone chargers have been
developed usually as emergency chargers. Since, the existing
chargers use variable voltages, they do not operate an optimum
performance. The chargers often develop low voltage than the
voltage required for charging of the phone. This charger usually
charge a set of battery by keeping them in parallel and then
these batteries are reconfigured to get the required charging
voltage of the mobile phone. The front cover used is glass, which
makes the charger heavy and fragile.
Solar cell industry is not competitive at present due to higher
material cost and due to high level of wastage owing to cell
chipping and breakage. These chipped and rejected cells can be
used more effectively for low power applications. These cells can
be laser cut to the required size and the performance can be
improved by AR coating to suite low power applications such as
torch, transistor, mobile phones etc.
OBJECTS OF THE INVENTION
It is an object of the invention to propose a solar - energy -
based portable mini chargers, adaptable in particular to mobile
phones which develop the required charge voltage for the mobile
phones.
Another object of the invention is to propose a solar - energy -
based portable mini chargersi adaptable to in particular mobile
phones which is cheap, unbreakable and light weighted.
A further abject of the invention is to propose a solar - energy -
based portable mini chargers, adaptable in particular to mobile
phones which is of simple configuration, smaller sized, and safe
in usage.
A still further object of the invention is to propose a solar -
energy - based portable mini chargers, adaptable in particular to
mobile phones, for which the cells of the charger are better
textured with improved efficiency.
SUMMARY OF THE INVENTION
Accordingly there is provided a solar charger for mobile phones,
comprising a plurality of crystalline solar cells laser cut
from full-size power module of cell size 125 mm x 125 mm re-
jected due to crack or breakge detected in main module product-
ion process, each cut cell providing an operating voltage and
2
current density about 0.5 - 0.6 V and 25 - 50 mA/cm , the
plurality of cells connected in series and laminated together to
form a foldable mini structure which enables outputting atleast
5 to 7 volts, and 340 to 360 ma, a UV - stabilized polycarbonate
sheet configured to form a front cover for the structure; and a
pouch formed of leather or UV - resistant plastic to accommodate
the folded cell structure with the front cover.
The charger is capable to charge the mobile phones by solar
energy. The charger utilizes the chipped cells from the main
module production line, as only the small size cells are
required, which are laser - cut from the chipped cells of full
size. The mobile charger is laminated with the front cover of
polyglass and is non - breakable* rugged and can be carried in a
shirt pocket. This can be directly hooked to a mobile phone with
charger kept under sunlight.
The details of the full cell & the cut cells used for the
invention, are as given below;
a. Typical full cell size-125mmx125mm
b. Optimum Cut cell size-62.5mmxl4mm
The invention utilizes rejected solar cells due to
breakage/cracks, for the manufacturing of a mobile phone charger.
These cells are normally cut into 12-14 pieces from each cell of
size given above and the useful pieces are taken to manufacture a
mobile phone charger. This ensures the effective utilization of
the complete solar cell area and thereby the best cost
optimisation of the product. The solar mobile charger, while kept
facing sun, can directly charge a mobile phone even without an
external battery & charging circuit.
Solar charger for mobile phone according to the invention, has
the capability of charging a number of mobile phones using
connectors of various types adaptable to mobile phones of
different makes/brands in the market. As per the configuration, a
c-Si Solar cell gives about 0.5-G.6 Volt and about 25-30mA/cm2 as
operating voltage and current densities respectively. To charge a
rechargeable battery of a mobile phone, it requires voltages in
the range of 5.3-6.2 volts. To achieve this, 12-14 nos. of c-Si
solar cells are connected in series for directly charging of
mobile phone. However, area per cell defines the charging rate of
the battery. To achieve optimum charging 14 nos. cells of
62.5mm x 14 mm size each have been connected in series and
packaged.
While configurating the charger, the load characteristics and the
battery requirement of the existing mobile phone chargers have
been studied and compared. Thus the following device parameters
have been adapted towards configuration of the novel chargers
? No. of Cells required for Charging 14
The mobile phone charger of the invention has the following features:
? Size = 140mmx70mmxl0mm
? Weight = 125 gram (including connector and lead)
? Output = 6 volt 350ma
? Time of charge = 40 -80 minutes
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows a pictorial view of the solar charger of the invention in
operating mode.
Figure 2 - Shows a pictorial view of the charger in folded condition.
Figure 3 - Shows the charger of the invention in portable mode.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Figure 1 shows the charger of the invention comprising a plurality of crystalline
solar cells (1) connected in series after laser cut. The cut cells with AR coating
(1) are laminated. The cell - structure (1) is covered with UV stabilized
polycarbonate sheet (2). The structure (1) is configured in foldable form and
accommodated in a leather pouch (3). The structure (1) is provided with a
charging lead (4), the other end of the lead (4) being adaptable to a mobile
phone (5).
WE CLAIM:
1. A solar charger for mobile phones comprising a
plurality of crystalline solar cells (1) laser cut from
full-size power module of cell size 125 mm * 125 rejected
due to crack or breakage detected in main module production
process, each cut cell (1) providing an operating voltage
and current density about 0.5 - 0.6 V and 25 - 50 mA/cm2 ,
the plurality of cells (1) foldable in series and laminated
together to form a foldable mini structure which enables
outputing at least 5 to 7 volts, and 340 to 360 ma, a UV -
stabilized polycarbonate sheet (2) configured to form a
front cover for the structure (1); and a pouch (3) formed
of leather or UV - resistant plastic to accommodate the
folded cell structure (1) with the front cover (2).
2. The solar charger as claimed in claim 1, wherein at-
least twelve to fourteen cut cells (1) are connected and
laminated to form the mini structure.
3. The solar charger as claimed in claim 1 or 2* wherein
the size of each cut cell (1) is about 63 mm x 14 mm.
4. The solar charger as claimed in claim 1, comprising a
charging lead (4), the other end of the charging lead (4)
being adaptable to a mobile phone.
5. A solar - energy - based portable mini charger
adaptable in particular to mobile phones as substantially
described herein with reference to the accompanying
drawings.

The invention relates to a solar charger for mobile phones comprising a plurality of crystalline solar cells (1) laser cut
from full-size power module of cell size 125 mm x 125 rejected due to crack or breakage detected in main module production process, each cut cell (1) providing an operating voltage
and current density about 0.5 - 0.6 V and 25 - 50 mA/cm2, the plurality of ceils (1) foldable in series and laminated together to form a foldable mini structure which enables outgoing at
least 5 to 7 volts, and 340 to 360 ma, a UV — stabilized poly-
carbonate sheet (2) configured to form a front cover for the
structure (1); and a pouch (3) formed of leather or UV - resis-
tant plastic to accommodate the folded cell structure (1) withthe front cover (2).