The present invention relates to a system for determining metrics of a battery and method of using thereof. More particularly, the present invention provides a system for determining the state of power and state of health and performance of a battery by measuring the temperature and impedance of the battery.
BACKGROUND OF THE INVENTION:
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. Lithium-ion 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 determines the life of the cell under specific thermodynamic and kinetic conditions like temperature, voltage limits, current rates, etc.
The understanding of the thermodynamics of the electrode reactions and the simultaneous physical processes in a cell is a field that is continuously advancing. The gained knowledge is crucial in determining and predicting the cell metrics that are required for the stability, longevity and optimal performance of the cell. The health of an electrochemical system is one such metric, which expresses the safety, longevity and usability of said system.
Electrochemical impedance spectroscopy (EIS) measurement system for characterizing lithium ion (Li-Ion) and other types of batteries is one way of determining the cell metrics. EIS is a

safe perturbation technique used to examine processes occurring inside electrochemical systems. Multi frequency impedance measurement of the battery can help establish the live state of the electrochemical system. The data can determine the state of health (SOH), State of Power (SOP), state of charge (SOC) and other internal metrics like temperature and SEI layer thickness of a battery.
State of Power (SOP) of a lithium-ion battery is essentially the maximum power a battery can deliver or accept within the safe operating area of the battery. The SOP of the battery varies a lot over one cycle. The multi frequency impedance measurement data along with the temperature data can help understand the metrics of the cell to enable optimized power performance of the battery. The health of an electrochemical system is expressed in the industry-accepted terminology of State of Health, which is a metric that indicates the maximum capacity of the battery at that instance, thereby also indicating the remaining life of the battery. Conventionally, the State of Health (SOH) is defined in percentage terms as the maximum capacity of an electrochemical system currently relative to the initial maximum capacity of the system. For automotive use, the SOH of a system is expected to be greater than 70-80%. The SOH also encompasses other characteristics of an electrochemical system like its safety and any physical damages. The physical damages i.e., the deformations of the cell affect its capacity thus affecting the SOH. 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 impedance, which is the cause for the ohmic heat generation.
The impedance 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 impedance of the cell increases non linearly

with the thickness of the SEI. With the increase in SEI thickness, the cell ages and the impedance increases.
The above processes contribute to the heat generation in an electrochemical system.
KR20180099668A discloses a battery and an electrical device including a battery management system. The battery management system includes a controller in electrical communication with a pressure sensor for monitoring a health condition of the battery. The controller uses a mechanical signal of force measurements in combination with incremental capacity analysis to estimate the capacity fading and other health indicators of the battery. The pressure sensor may provide a force measurement signal to the controller, and the controller may determine which incremental capacity curve to use based on the battery for the particular battery. The controller then executes a program that utilizes stored incremental capacity curves based on data and force from the pressure sensor to estimate the capacity fade and signal health status percentage to the user. The main drawback of the invention is that the invention focusses on battery expansion characteristics as an indication of battery health, which is not a very reliable metric. Additionally, the invention cannot be scaled from a cell health determination to a battery pack health determination reliably.
CN105301509B proposes the combined estimation methods of a kind of charge states of a lithium-ion battery, health status and power rating, health status including On-line Estimation battery: the recurrent least square method on-line identification open-circuit voltage with forgetting factor and impedance are used, and according to the OCV-SOC corresponding relationship indirect gain state-of-charge pre-established. The main drawback of this invention is that the described processes are computationally intensive requiring a higher grade of microcontroller involving higher costs. Additionally, the invention also uses complex processes involving the determination of State of Charge and State of Health in parallel with the impedance.
There is a need for a device that has a simpler computation process and is based on more reliable metrics than cell expansion characteristics.
The present invention discloses a system that uses a plurality of sensors such as temperature sensors and current sensors and impedance measuring ADCs to collate the temperature data and the impedance data of the battery in real-time under the real-time current conditions, processes it to determine the State of Health and state of Power of the battery.

OBJECT OF THE INVENTION:
The primary objective of the present invention is to disclose a system for determining metrics of a battery and method of using thereof for determining the State of Health and State of Power of a battery by using the temperature measurements and impedance measurement of the said battery.
Another object of the invention is to disclose a method to determine the dependence between the internal impedance of the battery and the temperature, thus establishing the temperature and SOH and SOP dependence of the battery.
Yet another object of the invention is to use the science of waste heat generation and its association to the health of the battery. The increase in waste heat generation is implicative of reduced efficiency and therefore poor health of the battery. The present invention uses temperature measurements through sensors to determine the waste heat generated and then derive an indication for the health of the battery.
Still another object of the invention is to develop a system that is as computationally inexpensive as possible for the determining the State of Health of battery.
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.
SUMMARY OF THE INVENTION:
In accordance with the main embodiment of present invention, a system for determining metrics of a battery is disclosed, comprising: a plurality of sensors configured to sense data inputs from the said battery; a processor to process the said data inputs received from the said plurality of sensors; a device, comprising: a plurality of temperature monitoring integrated circuits; a plurality of current monitoring circuits; and a plurality of time measurement circuits; a variable frequency AC current generator; and a plurality of analog signals conditioning circuitries; and the method comprising the steps of: measuring, temperature of the said battery by means of temperature sensors configured at strategic locations of the said battery; receiving, the data inputs by means of the device; processing, the said data by means of processor; creating, a temperature profile of the said battery; determining, the metrics of the battery using collected temperature data input of the said battery; wherein the metrics of the battery include

but are not limited to: the multi frequency impedance of the said battery; the heat generated due to the polarization, reaction and the impedance; the State of Health of the said battery; and the State of Power of the said battery.
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 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 graphical representation of the correlation between the maximum temperature and the impedance of the cell against a variety of current drawn and the ambient temperature.
Figure 2 illustrates a graphical representation of the correlation between the minimum temperature and the impedance of the cell against a variety of current drawn and the ambient temperature.
Figure 3 illustrates a temperature profile of a battery pack wherein the current is 1.7A, impedance is 30 mO and the ambient temperature is 25 °C.
Figure 4 illustrates a temperature profile of a battery pack wherein the current is 1.7A, impedance is 40 mO and the ambient temperature is 25 °C.
Figure 5 illustrates a temperature profile of a battery pack wherein the current is 1.7A, impedance is 50 mO and the ambient temperature is 25 °C.
Figure 6 illustrates a temperature profile of a battery pack wherein the current is 2.5A, impedance is 30 mO and the ambient temperature is 25 °C.
Figure 7 illustrates a temperature profile of a battery pack wherein the current is 2.5A, impedance is 40 mO and the ambient temperature is 25 °C.

Figure 8 illustrates a temperature profile of a battery pack wherein the current is 2.5A, impedance is 50 mO and the ambient temperature is 25 °C.
Figure 9 illustrates a system architecture which aimed at impedance measurement of the Lithium-ion Cell at many frequencies and different temperatures.
DETAILED DESCRIPTION:
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 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 present invention, a system for determining metrics of a battery is disclosed, comprising: a plurality of sensors configured to sense data inputs from the said battery; a processor to process the said data inputs received from the said plurality of sensors; a device, comprising: a plurality of temperature monitoring integrated circuits; a plurality of current monitoring circuits; and a plurality of time measurement circuits; a variable frequency AC current generator; and a plurality of analog signals conditioning circuitries; wherein, the plurality of sensors is configured at a plurality of strategic locations to sense the data inputs relating to the temperature profile of the said battery, and the said data inputs sent to the said device on a real time basis which is capable to receiving and processing the said data inputs by means of the processor in order to determine the state of health, state of power and impedance of the battery; wherein the plurality of current monitoring circuits receives the current measurements which assists in determination of the impedance of the said battery; the plurality of time measurement circuits determines the rate of change of temperature with time.
In accordance with the present invention, wherein the device feeds the processed temperature data input to the function configured to determines the impedance of the said battery, the said measured impedance is again transferred to the subsequent function based on the mapping of impedance to the SOH of the said battery, the said mapping is predetermined using data collected by the experiments with varying metrics and stored in the device; wherein as the battery is heated, the maximum temperature is recorded as the highest temperature reached by any region of the battery during the discharge process after the battery reaches the state of thermal equilibrium and the minimum temperature of the said battery is recorded as the lowest temperature at that region of the said battery; wherein the said variable frequency AC current generator is controlled by the micro-controller unit (MCU), provides the current at varying frequencies to the targeted lithium cell which is selected using the multiplexer or the switch; and the method comprising the steps of: measuring, temperature of the said battery by means of temperature sensors configured at strategic locations of the said battery; receiving, the data inputs by means of the device; processing, the said data by means of processor; creating, a temperature profile of the said battery; determining, the metrics of the battery using collected temperature data input of the said battery.

In accordance with the present invention, the factors including impedance and overall heat generation, the present invention then yields a State of Health metric for the electrochemical system in real-time. The algorithm in the invention accommodates for impedance variation with ambient temperatures and the state of charge of the cell. The algorithm adjusts for the change in resistance due to the temperature, if the operating conditions are not at optimal temperature. It is also known that the impedance of a cell varies in a single charge or discharge cycle as the state of charge of the cell varies. This variation is also accommodated in the State of Health determination algorithm.
As per Figure 1 and Figure 2 of the present invention, the graphs of the overall trends of temperature with the ambient temperature and the impedance is disclosed wherein the currents of 17 A, 25A and 30A are drawn from the battery, which result in a current of 1.7 A, 2.5 A and 3 A correspondingly from each cell and the ambient temperature varies between 25°C, 30°C, 35°Cand40°C.
As per Figure 3 to Figure 8 of the present invention, the visual representation of the temperature profile of the battery during the experiments was generated and is displayed wherein the temperature profile of the said battery is generated by means of the plurality of temperature sensors configured to measure the temperature at various locations of the said battery, the data input is sent to the device capable of receiving and processing the data by means of the processor in order to determine the state of health, state of power and impedance of the battery.
Further, as per Figure 9 of the present invention, the part of the block which is aimed at impedance measurement of the Lithium ion Cell at many frequencies and different temperatures
The data collected during the experiments is shown in the following table:

S.No. Electrical parameters Ambient Temperature Result

Current
Draw by
Battery Pack Current
draw per
cell Impedance of cell
Max. temp. Min. Temp.

A A mQ degC degC degC
1 17 1.7 30 25 69.8 28.8
2 17 1.7 30 30 74.3 33.8
3 17 1.7 30 35 78.9 38.8
4 17 1.7 30 40 83.4 43.8
5 17 1.7 40 25 83.8 30.1
6 17 1.7 40 30 88.2 35.1
7 17 1.7 40 35 92.6 40.1
8 17 1.7 40 40 97.1 45.1
9 17 1.7 50 25 97.4 31.4
10 17 1.7 50 30 102 36.4
11 17 1.7 50 35 106 41.4
12 17 1.7 50 40 110 46.4
13 25 2.5 30 25 117 33.3
14 25 2.5 30 30 121 38.3
15 25 2.5 30 35 125 43.3
16 25 2.5 30 40 130 48.3

17 25 2.5 40 25 144 36.1
18 25 2.5 40 30 148 41.1
19 25 2.5 40 35 152 46.1
20 25 2.5 40 40 156 51.1
21 25 2.5 50 25 171 38.9
22 25 2.5 50 30 174 43.9
23 25 2.5 50 35 178 48.9
24 25 2.5 50 40 180 53.9
25 30 3 30 25 153 37
26 30 3 30 30 157 42
27 30 3 30 35 161 47
28 30 3 30 40 165 52
29 30 3 40 25 190 41
30 30 3 40 30 194 46
31 30 3 40 35 197 51
32 30 3 40 40 201 56
33 30 3 50 25 225 45

34 30 3 50 30 229 50
35 30 3 50 35 232 55
36 30 3 50 40 236 60

We Claim:

1. A system for determining metrics of a battery, comprising:
a. a plurality of sensors configured to sense data inputs from the said battery;
b. a processor to process the said data inputs received from the said plurality of
sensors;
c. 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;
d. a variable frequency AC current generator; and
e. a plurality of analog signals conditioning circuitries;
wherein, the plurality of sensors is configured at a plurality of strategic locations to sense the data inputs relating to the temperature profile of the said battery, and the said data inputs sent to the said device on a real time basis which is capable to receiving and processing the said data inputs by means of the processor in order to determine the state of health, state of power and impedance of the battery; wherein the plurality of current monitoring circuits receives the current measurements which assists in determination of the impedance of the said battery; the plurality of time measurement circuits determines the rate of change of temperature with time;
wherein the device feeds the processed temperature data input to the function configured to determines the impedance of the said battery, the said measured impedance is again transferred to the subsequent function based on the mapping of impedance to the SOH of the said battery, the said mapping is predetermined using data collected by the experiments with varying metrics and stored in the device;
wherein as the battery is heated, the maximum temperature is recorded as the highest temperature reached by any region of the battery during the discharge process after the battery reaches the state of thermal equilibrium and the minimum temperature of the said battery is recorded as the lowest temperature at that region of the said battery;
wherein the said variable frequency AC current generator is controlled by the micro-controller unit (MCU), provides the current at varying frequencies to the targeted lithium cell which is selected using the multiplexer or the switch.

2. The system for determining metrics of a battery as claimed in claim 1, wherein the plurality of analog signal conditioning circuitry is an analog front-end (AFE) capable of receiving the sensor's signal and transforming it for the MCU for its use.
3. The system for determining metrics of a battery as claimed in claim 1, wherein the device is mounted on a printed circuit board or a flexible circuit board.
4. The system for determining metrics of a battery as claimed in claim 1, wherein the metrics of the battery include but are not limited to: the multi frequency impedance of the said battery; the heat generated due to the polarization, reaction and the impedance; the State of Health of the said battery; and the State of Power of the said battery.
5. The system for determining metrics of a battery as claimed in claim 1, wherein the device is retrofitted or inbuilt with the said battery.
6. The system for determining metrics of a battery as claimed in claim 1, wherein the configuration of the said battery is 14S10P which represents the matrix of cells with 14 cells in series and 10 cells in parallel, where each cell has a nominal voltage of 3.6V and capacity of 2.6 Ah and total battery voltage is 14*3.6 V with capacity of 10*2.6 Ah, i.e., 50.4 V and 26 Ah.
7. The system for determining metrics of a battery as claimed in claim 1, wherein the device comprises:
a. a plurality of resistors;
b. a plurality of capacitors; and
c. a plurality of inductors.
8. The system for determining metrics of a battery as claimed in claim 7 wherein, the said plurality of resistors, capacitors and inductors are positioned in electrical communication with multiple components of the integrated circuits.
9. The method for determining metrics of a battery, comprising the steps of:
i. measuring, temperature of the said battery by means of temperature sensors
configured at strategic locations of the said battery; ii. receiving, the data inputs by means of the device; iii. processing, the said data by means of processor; iv. creating, a temperature profile of the said battery;
v. determining, the metrics of the battery using collected temperature data input of the said battery;

wherein the metrics of the battery include but are not limited to: the multi frequency impedance of the said battery; the heat generated due to the polarization, reaction and the impedance; the State of Health of the said battery; and the State of Power of the said battery.
10. The system for determining metrics of a battery as claimed in claim 1, wherein device is either a component of the electrochemical cell, or a part of a package that comprises the device and multiple electrochemical cells as present in the battery pack.