The present invention relates to a temperature measurement device as a tool for diagnostics
and predicting warranty abuses of the battery. Particularly, the present invention relates to a
system for diagnosing an internal resistance of a plurality of damaged cells of the battery.
BACKGROUND:
Over the last few decades, advances in electrochemical systems have expanded the capabilities
of these systems in a variety of fields including portable electronic devices, air and spacecraft
technologies, and automotive technologies. Many recent advances in electrochemical systems
are owing to the discovery and integration of new materials for battery components. Lithiumion battery technology has been at the forefront of this advancement. The research in advanced
electrode materials has significantly enhanced the energy capacities, energy densities,
discharge current rates and cycle life provided by these electrochemical cells, positioning
lithium-ion batteries to be the preferred technology for use in hybrid electric vehicles (HEV)
and electric vehicles (EV).
Electrochemical cells have two electrodes; an anode and a cathode, which are electrical
conductors, separated by a purely ionic conductor, the electrolyte. The capacity for positive
and negative ion exchanges at the electrodes with the electrolyte due to chemical reactions and
complementary physical processes results in the generation of electric current. The processes
simultaneously absorb or generate electrons to maintain the electrical neutrality of the whole
system. The potential of each electrode and the reaction rate affect the power density and
energy output of the cell. For rechargeable batteries, the extent of changes at the electrode
surface determine the life of the cell under specific thermodynamic and kinetic conditions like
temperature, voltage limits, current rates, etc.
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Any electrochemical system generates heat broadly due to three reasons, which are the reaction
heat, the polarization heat and the ohmic heat.
The reaction heat is generated due to the electrochemical reaction that takes place that is the
source of the system’s energy. A side product of the reaction is heat. The polarization heat is
generated because of mechanical effects occurring at the interface between electrodes and
electrolyte. Accumulation of gases and development of concentration gradients of reagents at
such interfaces lead to polarization which in turn reduces the efficiency of the cell by
increasingly transforming energy desired for electrochemical potential into heat. Any
electrochemical system has an intrinsic property of an internal resistance, which is the cause
for the ohmic heat generation.
The internal resistance of a battery increases with age primarily due to the formation of a layer
at the anode of the cell. This layer is the solid electrolyte interphase (SEI) layer, the thickness
of which increases as the cell is used, inhibiting further electrolyte decomposition. This
inhibition is the primary cause for the ageing of the cell. The internal resistance of the cell
increases non linearly with the thickness of the SEI. With the increase in SEI thickness, the cell
ages and the internal resistance increases.
The above processes contribute to the heat generation in an electrochemical system.
For the above reasons, the temperature of the electrochemical system should be maintained in
the composite cell’s optimal temperature range for best performance.
Typically, said temperature range is provided by the manufacturer, and tends to lie between 15
℃ to 35 ℃.
A battery is a specific electrochemical system where cells are arranged in a matrix to increase
capacity and output voltage. In a battery consisting of a matrix of cells, the weakest cell
becomes the bottleneck in performance. The supply from the battery is switched off when any
cell reaches the voltage cutoff limit which is pre-decided by the manufacturer. The weakest
cell triggers the power supply cut off function, as it is the first to reach the lower limit owing
to its relatively lower total capacity.
The creation of significant differences in the ageing processes of each cell in a battery depends
primarily on the temperature of each cell's surrounding. If the design or manufacturing of the
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battery has susceptibilities that lead to an imbalanced temperature profile, the cells in the region
of the battery pack having higher temperatures will age faster compared to other cells.
If the cell has aged or is damaged, the charge and discharge process will generate more heat
and thus the cell's immediate surroundings will be warmer than the other cell's surroundings.
The damaged cell, apart from being a bottleneck, will further incur damage to the neighbouring
cells due to exposure to higher temperatures.
SUMMARY OF INVENTION:
In accordance with the main aspect of invention, a system for predicting warranty abuses of a
battery is disclosed, comprising: a plurality of sensors configured to sense data inputs from the
said battery; a device, comprising; a plurality of temperature monitoring integrated circuits; a
plurality of current monitoring circuits; and a plurality of time measurement circuits, a
processor to process the said data inputs received from the said plurality of sensors; a display
module attached to the said device.
In the present invention, a plurality of damaged cells with higher internal resistance value are
diagnosed by monitoring a temperature of the said plurality of damaged cells by means of the
plurality of sensors placed at a plurality of strategic locations of the said battery. The sensed
data inputs of the said battery on a real time basis are transferred to the said device capable to
process the said input data and displayed to the display module attached to the said device.
Other objects and advantages of the present invention will become apparent from the following
description taken in connection with the accompanying drawings, wherein, by way of
illustration and example, the aspects of the present invention are disclosed.
BRIEF DESCRIPTION OF DRAWINGS:
The present invention will be better understood after reading the following detailed description
of the presently preferred aspects thereof with reference to the appended drawings, in which
the features, other aspects and advantages of certain exemplary embodiments of the invention
will be more apparent from the accompanying drawings in which:
Figure 1 illustrates a battery which indicates 5 defective cells in purple colour.
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Figure 2 illustrates a temperature profile for the battery where defective cell internal resistance
= 60 mΩ, normal internal resistance = 30 mΩ, ambient temperature = 25℃, current drawn =
1.7A.
Figure 3 illustrates a temperature profile for the battery where defective cell internal resistance
= 350 mΩ, normal internal resistance = 30 mΩ, ambient temperature = 25℃, current drawn =
1.7 A.
Figure 4 illustrates a temperature profile for the battery where defective cell internal resistance
= 700 mΩ, normal internal resistance = 30 mΩ, ambient temperature = 25℃, current
drawn=1.7 A.
DETAILED DESCRIPTION OF DRAWINGS:
The following description describes various features and functions of the disclosed device and
methods with reference to the accompanying figures. In the figures, similar symbols identify
similar components, unless context dictates otherwise. The illustrative aspects described herein
are not meant to be limiting. It may be readily understood that certain aspects of the disclosed
system, method and apparatus can be arranged and combined in a wide variety of different
configurations, all of which are contemplated herein.
These and other features and advantages of the present invention may be incorporated into
certain embodiments of the invention and will become more fully apparent from the following
description and claims or may be learned by the practice of the invention as set forth
hereinafter.
Accordingly, those of ordinary skill in the art will recognize that various changes and
modifications of the embodiments described herein can be made without departing from the
scope of the invention. In addition, descriptions of well- known functions and constructions
are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the
bibliographical meanings, but, are merely used to enable a clear and consistent understanding
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of the invention. Accordingly, it should be apparent to those skilled in the art that the following
description of exemplary embodiments of the present invention are provided for illustration
purpose only and not for the purpose of limiting the invention.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless
the context clearly dictates otherwise.
It should be emphasized that the term “comprises/comprising” when used in this specification
is taken to specify the presence of stated features, integers, steps or components but does not
preclude the presence or addition of one or more other features, integers, steps, components or
groups thereof.
In accordance with the main aspect of invention, a system for predicting warranty abuses of a
battery is disclosed, comprising: a plurality of sensors configured to sense data inputs from the
said battery; a device, comprising; a plurality of temperature monitoring integrated circuits; a
plurality of current monitoring circuits; and a plurality of time measurement circuits, a
processor to process the said data inputs received from the said plurality of sensors; a display
module attached to the said device.
In the present invention, a plurality of damaged cells with higher internal resistance value are
diagnosed by monitoring a temperature of the said plurality of damaged cells by means of the
plurality of sensors placed at a plurality of strategic locations of the said battery. The sensed
data inputs of the said battery on a real time basis are transferred to the said device capable to
process the said input data and displayed to the display module attached to the said device.
As per Figure 1 of the present invention, a battery is indicated wherein a plurality of damaged
cells are indicated. Particularly, five damaged cells (in purple colour) are indicated.
It is important to mention here that the rise in internal resistance of the electrochemical cell
with the age of the cell results in higher temperatures for the same current being drawn from
the cell at a later age. For a healthy battery, there is no significant difference between the ageing
processes for each cell, and therefore the heat generated by each cell is similar owing to no
significant differences in the internal resistances of the cells. A damaged cell has a markedly
high internal resistance and thus generates more heat, raising the temperature in the
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neighbourhood of the cell. Additional reasons may contribute to the heat generation as
previously mentioned such as the reaction heat and the polarization heat.
Figure 2 of the present invention illustrates a temperature profile for the battery. It can be
importantly noted that the internal resistance of the plurality of damaged cells is higher as
compared to that of the plurality of normal cells.
Particularly, it can be noted from the Figure 2 of the present invention that the internal
resistance value of the plurality of damaged cell is 60 mΩ. In the case of normal cells, it is - 30
mΩ. The ambient temperature of the said battery is 25 degree celcius and the current drawn is
1.7A.
Similarly, looking at Figure 3 which includes 3a 3b of the present invention, the battery can be
seen wherein the temperature of the plurality of damaged cells is 350 mΩ. In the case of normal
cells, it is - 30 mΩ. The ambient temperature of the said battery is 25 degree celcius and the
current drawn is 1.7A.
Figure 4 illustrates the battery wherein the temperature of the plurality of damaged cells is 700
mΩ. In the case of normal cells, it is - 30 mΩ. The ambient temperature of the said battery is
25 degree celcius and the current drawn is 1.7A.
As it can be noted from the above, that the temperature of the plurality of damaged cells is
higher as compared to that of the normal cells.
Theefore, in accordance with the present invention – a plurality of sensors are used to collect
data inputs pertaining to internal resistance of the plurality of damaged cells. The plurality of
sensors used in the present invention are including but not limited to the temperature sensors.
The said plurality of temperature sensors are placed at the plurality of strategic locations of the
said battery. The said plurality of temperature of sensors sends the data inputs to the said device
capable of processing the said data inputs. The device takes measurements from the
temperature sensors at strategically placed locations on the battery, and creates a heatmap that
elicits the approximate temperatures through the volume of the battery. The healthy
temperature profile of a battery is taken into account by the device as a reference point,
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therefore the algorithm carried by the device can identify any anomalies that may be caused by
reasons that include but are not limited to faulty cells, design flaws and manufacturing flaws.
The heatmap may be used as a tool for battery diagnostics. The heatmap may also be used as a
tool to predict warranty abuses by identifying characteristics that indicate that the battery is
being used outside predefined usage boundaries.

We Claim:

1. A system for diagnosing an internal resistance of a damaged cell of a battery,
comprising:
a. a plurality of sensors configured to sense data inputs from the said battery;
b. a device, comprising;
i. a plurality of temperature monitoring integrated circuits;
ii. a plurality of current monitoring circuits; and
iii. a plurality of time measurement circuits,
c. a processor to process the said data inputs received from the said plurality of
sensors;
d. a display module attached to the said device;
wherein, a plurality of damaged cells with higher internal resistance value are
diagnosed by monitoring a temperature of the said plurality of damaged cells by means
of the plurality of sensors placed at a plurality of strategic locations of the said battery,
wherein, the sensed data inputs of the said battery on a real time basis are transferred
to the said device capable to process the said input data and displayed to the display
module attached to the said device.
2. The system as claimed in claim 1 wherein, the plurality of sensors used are temperature
sensors.
3. The system as claimed in claim 1 wherein, the device may be mounted on a printed
circuit board or a flexible circuit board.
4. The system as claimed in claim 1 wherein, the device further comprising:
a. a plurality of resistors;
b. a plurality of capacitors; and
c. a plurality of inductors.
5. The system as claimed in claim 4 wherein, the said plurality of resistors, capacitors and
inductors are positioned in electrical communication with one or more components of
the integrated circuits.
6. The system as claimed in claim 1 wherein, the said system for monitoring the health
can also be used in varied electrochemical devices and supercapacitors.