Description:TITLE OF THE INVENTION: AN APPARATUS FOR SURVEILLING AN ENERGY STORAGE SYSTEM OF A VEHICLE
FIELD OF THE INVENTION
The present disclosure is generally related to energy storage systems of vehicles. Particularly, the present disclosure is related to surveilling of vehicle energy storage systems. More particularly, the present disclosure is related to an apparatus for surveilling an energy storage system of a vehicle.
BACKGROUND OF THE INVENTION
Modern vehicles are fitted with electrochemical energy storage stores, to supply at least some drive power, irrespective of whether they are of fully electric or hybrid configuration. Energy storage systems (for example, batteries), and particularly, energy storage systems with numerous individual cells connected in series, typically provide such energy stores, for the drive (traction).
Electrochemical cells (also referred to as a “cell” and/or “cells”), in the form of lithium-ion accumulators, are now the technology of choice, with the energy storage systems generally being high-voltage batteries or traction batteries.
Real-time voltage monitoring, and accurate SOC (State of Charge) estimation, are crucial factors, when assessing the health of the energy storage systems. These help a user gain a better understanding of: charging and discharging cycles; and time required, for charging and discharging, over a long period of time.
Voltage switching, as per requirements, during charging and/or discharging of the energy storage systems, enables: preventing the cells of the energy storage systems, from operating outside of their operating temperature ranges; monitoring excess charge/discharge currents, as per a current status of the energy storage systems; critical fault diagnoses; and/or better control, on power flow, to a powertrain.
Though there are some solutions that are available, for surveilling energy storage systems of vehicles, none of the solutions are comprehensive enough.
The available solutions are for low wattage (and/or low voltage) energy storage systems, and offer basic cell data monitoring and logging features. Further, they cannot work, at multiple voltages. They are also usually not scalable (to higher voltages), and do not have the flexibilities, to be integrated, into any kind of energy storage system.
High vehicle range and top speed requirements require high voltage powertrain; hence the electric vehicle market, and particularly the electric vehicle two-wheeler market, is transitioning to higher power systems, but at the cost of increased complexity. Such energy storage systems are difficult to monitor and involve advanced wiring topologies. Multiple low power surveilling solutions (that are cascaded) increase wiring complexities and sometimes cause packaging issues.
There is, therefore, a need in the art, for: an apparatus for surveilling an energy storage system of a vehicle, which overcomes the aforementioned drawbacks and shortcomings.
SUMMARY OF THE INVENTION
An apparatus for surveilling an energy storage system of a vehicle that is configured to switch between two different voltages, during charging and discharging of said energy storage system, is disclosed. Said apparatus broadly comprises: a plurality of tracking members; an at least a switching member; an at least a primary controller; an at least an ascertaining member; and an at least a power supply member.
Said plurality of tracking members facilitates monitoring and logging of a plurality of parameters, of each cell, in said energy storage system, in real-time. Data sensed, by said plurality of tracking members, is (or are) transmitted to said at least one primary controller.
Each tracking member, among said plurality of tracking members, is configured to interact with each cell (or a pre-defined number of cells), among a plurality cells, of said energy storage system. Said each tracking member, among said plurality of tracking members, is associated with other tracking members (for example, through differential pair mechanism).
A first tracking member acts as a base tracking member, with the rest of said tracking members being stacked, one after another, and acting under control of said base tracking member.
In an embodiment, said plurality of parameters monitored and logged, by said plurality of tracking members, includes: voltage; temperature; and/or the like.
Said each tracking member, among said plurality of tracking members, may be assigned with a unique user-defined address, for easy accessibility and identification. Said each tracking member, among said plurality of tracking members, may interact with a maximum of about 16 cells that are connected in series.
In an embodiment, communication between said at least one primary controller and said plurality of tracking members is established, through a single-ended Universal Asynchronous Receiver/Transmitter (UART).
A voltage sensing member is associated with each cell (or said pre-defined number of cells), among said plurality of cells. Said voltage sensing member is communicatively associated with a respective tracking member, among said plurality of tracking members, through a filtering member. In an embodiment, said filtering member is a passive RF filter.
A temperature sensing member is associated with each pair of cells, among said plurality of cells. Said temperature sensing member is communicatively associated with a respective tracking member, among said plurality of tracking members. In an embodiment, said temperature sensing member is a thermistor.
In an embodiment, said energy storage system comprises about 64 cells. Said about 64 cells are divided, into a plurality of packs, with about 16 cells per pack. Each pack is associated with a tracking member (among said plurality of tracking members) that receives: voltage (i.e., cell voltage) data, from about 16 cells; and 8 temperature-related data (i.e., cell temperature; one cell temperature-related data, for said each pair of cells, among said plurality of cells).
Said at least one switching member is configured to allow said plurality of packs, in said energy storage system, to: switch between parallel connection and series connection; and/or connect with (and/or disconnect from) a powertrain, as per instructions, from said at least one primary controller. Said switching, between said parallel connection and said series connection is performed, depending on an operating mode of said energy storage system. In an embodiment, said operating mode includes: a charging mode; and/or a discharging mode.
In an embodiment, said at least one switching member broadly comprises a plurality of swap-enabling members, which is divided, into two segments. Said plurality of swap-enabling members, in a first segment, is configured to allow said plurality of packs, to switch between said parallel connection and said series connection. A plurality of swap-enabling members, in a second segment, is configured to connect with (and/or disconnect from) said powertrain.
Said at least one ascertaining member is communicatively associated with said energy storage system, through a shunt resistor. Said at least one ascertaining member is configured to determine: State of Charge; State of Health; cell impedance; remaining capacity; energy content; and/or the like, of said energy storage system.
In an embodiment, communication between said at least one primary controller and said at least one ascertaining member is established, through Inter Integrated Circuit communication.
Said at least one primary controller is configured to log all data received, in real-time, from said plurality of tracking members and said at least one ascertaining member. Said at least one primary controller facilitates tracking, monitoring, and controlling, of said apparatus.
The at least one power supply member supplies power to said apparatus. Said at least one power supply member prevents said apparatus, from stopping surveilling of said energy storage system, in case of supply faults, due to other subsystems.
In an embodiment, said apparatus is configured with galvanic isolation, between its components, thereby, isolating functional sections of said apparatus, to prevent current flow.
Method of working of said apparatus is also disclosed.
The disclosed apparatus offers at least the following advantages: is of plug and play nature; is scalable, to higher voltages; is capable of powertrain voltage switching; is capable of powertrain derating; has tuneable fault thresholds, as per real-time pack health status; offers passive cell balancing ensuring maximum cell usable capacity; provides active battery charge level indications and periodic range estimation; and is capable of performing: individual cell voltage monitoring and temperature monitoring, and pack current monitoring, cell overvoltage/undervoltage detection, cell over-temperature/under-temperature detection, cell overcharge/discharge protection; and cell undercharge detection.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates an apparatus for surveilling an energy storage system of a vehicle, in accordance with an embodiment of the present disclosure;
Figure 2 illustrates an at least a switching member, of an apparatus for surveilling an energy storage system of a vehicle, in discharging mode, in accordance with an embodiment of the present disclosure; and
Figure 3 illustrates an at least a switching member, of an apparatus for surveilling an energy storage system of a vehicle, in charging mode, in accordance with an embodiment of the present disclosure
DETAILED DESCRIPTION OF THE INVENTION
Throughout this specification, the use of the words “comprise” and “include”, and variations such as “comprises”, “comprising”, “includes”, and “including”, may imply the inclusion of an element (or elements) not specifically recited. Further, the disclosed embodiments may be embodied, in various other forms, as well.
Throughout this specification, the use of the word “apparatus” is to be construed as: “a set of technical components (also referred to as “members”) that are communicatively and/or operably associated with each other, and function together, as part of a mechanism, to achieve a desired technical result”.
Throughout this specification, the use of the words “communication”, “couple”, and their variations (such as communicatively), is to be construed as being inclusive of: one-way communication (or coupling); and two-way communication (or coupling), as the case may be.
Throughout this specification, the use of the word “surveilling”, and its variations, is to be construed as being inclusive of: “tracking; monitoring; recording; analysing; controlling; alerting; and/or the like, by an apparatus for surveilling an energy storage system of a vehicle”.
Throughout this specification, the use of the word “vehicle”, and its variations, is to be construed as being inclusive of: “electric vehicles; hybrid electric vehicles; conventional internal combustion engine vehicles; and/or the like”.
Throughout this specification, where applicable, the use of the phrase “at least” is to be construed in association with the suffix “one” i.e. it is to be read, along with the suffix “one”, as “at least one”, which is used in the meaning of “one or more”. A person skilled in the art will appreciate the fact that the phrase “at least one” is a standard term that is used, in Patent Specifications, to denote any component of a disclosure, which may be present (or disposed) in a single quantity, or more than a single quantity.
Throughout this specification, the use of the word “plurality” is to be construed as being inclusive of: “at least one”.
Throughout this specification, the words “the” and “said” are used interchangeably.
Throughout this specification, the phrases “at least a”, “at least an”, and “at least one” are used interchangeably.
Throughout this specification, the disclosure of a range is to be construed as being inclusive of: the lower limit of the range; and the upper limit of the range.
Also, it is to be noted that embodiments may be described as a method. Although the operations, in a method, are described as a sequential process, many of the operations may be performed in parallel, concurrently, or simultaneously. In addition, the order of the operations may be re-arranged. A method may be terminated, when its operations are completed, but may also have additional steps.
An apparatus for surveilling an energy storage system of a vehicle (also referred to as “apparatus”), which is configured to switch between two different voltages, as required, during charging and discharging of the energy storage system, is disclosed. In an embodiment of the present disclosure, as illustrated, in Figure 1, said apparatus (10) broadly comprises: a plurality of tracking members (12); an at least a primary controller (11); an at least a switching member (14); an at least an ascertaining member (13; for example, a gauge); and an at least a power supply member (15).
In another embodiment of the present disclosure, each tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12), is configured to interact with each cell (or a pre-defined number of cells), among a plurality of cells, of the energy storage system (17). Said plurality of tracking members (12) facilitates monitoring and logging of a plurality of parameters, of said each cell, in the energy storage system (17), in real-time. Data sensed, by the plurality of tracking members (12), is (or are) transmitted, to the at least one primary controller (11).
In yet another embodiment of the present disclosure, the plurality of parameters includes, but is not limited to: voltage; temperature; and/or the like.
In yet another embodiment of the present disclosure, said each tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12), is associated with other tracking members, where: a first tracking member (12a) acts as a base tracking member; and rest of the tracking members (12b, 12c, and 12d) are stacked, one after another, and act under control of the base tracking member (12a). Said plurality of tracking members (12) communicates with each other, through differential pair mechanism, which is well-known in the art.
Although the apparatus (10) has only been illustrated and described, with four tracking members, a person skilled in the art will appreciate the fact that said apparatus (10) may comprise any number of tracking members, as per requirements.
In yet another embodiment of the present disclosure, said each tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12), is assigned with a unique user-defined address, for easy accessibility and identification. The unique user-defined address may be of any suitable type known in the art.
In yet another embodiment of the present disclosure, said each tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12), interacts with a maximum of about 16 cells, which are connected in series.
In yet another embodiment of the present disclosure, communication between the at least one primary controller (11) and the plurality of tracking members (12) is established, through a single-ended UART (Universal Asynchronous Receiver/Transmitter).
A voltage sensing member (V) is associated with said each cell (or the pre-defined number of cells), among the plurality of cells, in the energy storage system (17). Said voltage sensing member (V) is communicatively associated with a respective tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12), through a filtering member.
In yet another embodiment of the present disclosure, the voltage sensing member (V) is a voltage sensor. The voltage sensor may be of any suitable type known in the art.
In yet another embodiment of the present disclosure, the filtering member is a passive RF filter.
A temperature sensing member (T; for example, a thermistor) is associated with each pair of cells, among the plurality of cells, in the energy storage system (17). Said temperature sensing member (T) is communicatively associated with a respective tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12).
In yet another embodiment of the present disclosure, the energy storage system (17) comprises about 64 cells. Said about 64 cells are divided, into a plurality of packs, with about 16 cells per pack. Each pack is associated with a respective tracking member (12a, 12b, 12c, or 12d), among the plurality of tracking members (12).
Said respective tracking member receives: voltage (i.e., cell voltage) data, from about 16 cells; and 8 temperature-related data (i.e., cell temperature; one cell temperature-related data, for said each pair of cells, among the plurality of cells).
The at least one ascertaining member (13) is communicatively associated with the energy storage system (17), through a shunt resistor (16). Said at least one ascertaining member (13) is configured to determine: State of Charge (SOC); State of Health (SOH); cell impedance; remaining capacity; energy content; and/or the like, of the energy storage system (17). The calculations involved, in such determinations, are known, to a person skilled in the art.
In yet another embodiment of the present disclosure, the shunt resistor (16) is an about 2 milliohms shunt resistor.
In yet another embodiment of the present disclosure, communication between the at least one primary controller (11) and the at least one ascertaining member (13) is established, through I2C (Inter Integrated Circuit) communication.
The at least one switching member (14) is configured to allow the plurality of packs, in the energy storage system (17), to: switch between parallel connection and series connection; and/or connect with (and/or disconnect from) a powertrain (18), as per instructions, from the at least one primary controller (11).
The switching between the parallel connection and the series connection is performed, depending on an operating mode of the energy storage system (17). Said operating mode of the energy storage system (17) is identified, by the at least one primary controller (11), and tracked continuously, in real-time.
In yet another embodiment of the present disclosure, the operating mode of the energy storage system (17) includes, but is not limited to: a charging mode; and/or a discharging mode.
In yet another embodiment of the present disclosure, the operating mode of the energy storage system (17) is determined, based on a state of a vehicle. If the vehicle is moving, the energy storage system (17) is determined as being, in the discharging mode. If the vehicle is plugged in, for charging, the energy storage system (17) is determined as being, in the charging mode.
In yet another embodiment of the present disclosure, the at least one switching member (14) comprises a plurality of swap-enabling members. Said plurality of swap-enabling members is divided, into two segments. A plurality of swap-enabling members, in a first segment, is configured to allow the plurality of packs, in the energy storage system (17), to switch between the parallel connection and the series connection. A plurality of swap-enabling members, in a second segment, is configured to connect with (and/or disconnect from) the powertrain (18).
In yet another embodiment of the present disclosure, the plurality of swap-enabling members is power MOSFETs.
In yet another embodiment of the present disclosure, the at least one switching member (14) comprises four swap-enabling members (M1, M2, M3, and M4).
If the energy storage system (17) is in the charging mode, the plurality of packs, in the energy storage system (17), is switched to the series connection. If the energy storage system (17) is in the discharging mode, the plurality of packs, in the energy storage system (17), is switched to the parallel connection.
The at least one switching member (14), in the discharging mode, is illustrated, in Figure 2. During the discharging mode, among the four swap-enabling members (M1, M2, M3, and M4), M1, M2, and M4, are activated. If the operating mode of the energy storage system (17) is identified, by the at least one primary controller (11), as the discharging mode, the at least one primary controller (11) instructs the at least one switching member (14) to activate only M1 and M2, to form a discharging circuit (D).
M1 and M2 are activated, to connect together positive and negative terminals of each pack (17a and 17b), among the plurality of packs, in the energy storage system (17). M4 is configured for enabling (and/or disabling) isolation of the energy storage system (17), from a rest of the powertrain (VL). Hence M4 is activated, only after M1 and M2 are activated. Therefore, by this way a parallel configuration is achieved, during the discharging mode, with the final powertrain voltage being equal to that of any of the packs, among the plurality of packs, in the energy storage system (17).
The at least one switching member (14), in the charging mode, is illustrated, in Figure 3. During the charging mode, among the four swap-enabling members (M1, M2, M3, and M4), M1, M2, and M3, are activated. If the operating mode of the energy storage system (17) is identified, by the at least one primary controller (11), as the charging mode, the at least one primary controller (11) instructs the at least one switching member (14) to activate only M1 and M2, to form a charging circuit (C).
M1 and M2 are activated, to connect together the positive terminal of one pack (17a) and the negative terminal of another pack (17b), in the energy storage system (17). The remaining terminals form output terminals of a series configuration. M3 is configured for enabling (and/or disabling) the isolation of the energy storage system (17), from the rest of the powertrain (VL). Hence, M3 is activated, only after M1 and M2 are activated, to connect the packs (17a and 17b) of the energy storage system (17), in the series configuration.
The at least one power supply member (15) supplies power to the apparatus (10). Said at least one power supply member (15) prevents the apparatus (10), from stopping surveilling of the energy storage system (17), in case of supply faults, due to other subsystems.
In yet another embodiment of the present disclosure, the apparatus (10) is configured with galvanic isolation, between its components, thereby, isolating functional sections of the apparatus (10), to prevent current flow. The galvanic isolation may be achieved, through any suitable techniques, which are known in the art.
In yet another embodiment of the present disclosure, the apparatus (10) communicates with a vehicle control unit (18; VCU) or other external devices, through CAN (Controller Area Network) bus. The VCU (18) may be of any suitable type known in the art.
The at least one primary controller (11) is configured to log all the data received, in real-time, from the plurality of tracking members (12) and the at least one ascertaining member (13). The at least one primary controller (11) may be of any suitable type known in the art.
In yet another embodiment of the present disclosure, the at least one primary controller (11) facilitates tracking, monitoring, and controlling, of the apparatus (10). The operations performed, by the at least one primary controller (11) include, but are not limited to: determination of the operating mode of the energy storage system (17) or state of the vehicle; configuration and addressing of the plurality of tracking members (12) to allow for each of the cells, in a pack, to be accessed; data sampling and logging of the cells; communication between the VCU (18) and the apparatus (10); sending cell data, to the VCU (18), and receiving a required message stack, back from the VCU (18); and fault detection and handling, by computing if cell parameters exceed safe operating ranges.
In yet another embodiment of the present disclosure, safe operating ranges of the apparatus (10) are: about 80 V DC, 160 A to about 268 V DC, 80A, with a temperature of less than about 105 degree Celsius.
Said at least one primary controller (11) performs the following operations:
• Keeps constant communication with the VCU (18) and checks if calibration command is given; the apparatus (10) resets and calibrates initial settings, as per the calibration command.
• The plurality of tracking members (12) is checked, for any initial faults, which are cleared, if found.
• The plurality of tracking members (12) undergoes indexed-addressing, as per the energy storage system (17) handled, and is further configured for data sampling rates and communication protocol requirements.
• Determines the vehicle state, by communicating with the VCU (18).
• Instructs the at least one switching member (14) to allow the plurality of packs, in the energy storage system (17), to: switch between the parallel connection and the series connection; and connect with (and/or disconnect from) the powertrain (18).
Initial calibration of the apparatus (10) is performed, based on the following parameters. Said parameters are not exclusive.
1. Number of the cells, among the plurality of cells, in the energy storage system (17), connected in series, and number of the cells, among the plurality of cells, in the energy storage system (17), connected in parallel;

2. Initial Charge Content or SoC of said each cell, among the plurality of cells, in the energy storage system (17);

3. Minimum and maximum allowable cell voltage of said each cell, among the plurality of cells, in the energy storage system (17);

4. c-rate of the energy storage system (17); and

5. Initial temperature of said each cell, among the plurality of cells, in the energy storage system (17).
The initial faults include, but are not limited to: internal communication of various components of the apparatus (10); communication between the apparatus (10) and other external peripherals (for example, the VCU); and improper electrical connections, between the cells of the energy storage system (17).
Charging Mode (or the vehicle is connected with a charger):
The plurality of tracking members (12) is accessed, for cell voltage, cell temperature data, and any other auxiliary data, alongside the at least one ascertaining member (13). All recorded data is (or are) checked against critical thresholds, which are known to a person skilled in the art, and may vary, based on requirements and configuration.
In case of no errors, the cells are checked, for their current voltage levels, and subjected to passive balancing, whenever needed. The apparatus (10) is checked, for any existing faults, periodically. The at least one switching member (14) is made to connect, in a configuration, which connects the packs, for charging.
Throughout this specification, the use of the phrase “critical threshold”, and its variations, is to be construed as: “the limiting values of the parameters, of said each cell, among the plurality of cells, in the energy storage system (17), which, when crossed, cause said each cell, to get stressed, and discharge or charge inappropriately, resulting in: over-discharging; overcharging; and/or overheating, thus, resulting in a thermal runaway.
Fault Detection:
An efficient fault detection mechanism is implemented, with primary and secondary level thresholds; the faults detected are checked twice and a warning is generated, for the VCU (18), alongside a concerned flag being raised and communicated to the VCU (18). Since checking is performed twice, the detected faults are considered as critical conditions, and the at least one switching member (14) is de-energised instantly, disconnecting any power flow, from the energy storage system (17), to the rest of the powertrain (18). The vehicle is to be restarted, after such a shutdown.
The primary thresholds allow the cells of the energy storage system (17), to work at full potential, at safest achievable conditions. Said thresholds are to be considered, only if the cells are used at their full capacity.
For improving longevity of the cells, operating conditions need to be more restricted, such that the cells function, without any additional loads, under most optimum temperature ranges (their internal impedances and SOC are subjected to almost no disturbances; hence, there is just the right amount of current exchange, from the cells not causing excessive heat losses).
This above kind of operation improves cell life time and range; since usual battery usage, on city roads, is not rigorous enough, reducing thresholds does not compromise, on the performance of the vehicle.
In yet another embodiment of the present disclosure, the flags are single digit variables defined to store only 2 kinds of values, each corresponding to a particular logic, which attains only 2 operational states. A value of ‘1’ attained, by the flag, implies that the flag is raised and one state of the apparatus (10) is achieved. A value of ‘0’ attained, by the flag, implies that the flag is reset, and a complimentary state of the apparatus (10) is achieved.
The flags are used to indicate, but are not limited to: fault states; and/or non-faulty states (like overvoltage flag, undervoltage flag, over-temperature flag, over-current flag, overcharge flag, over-discharge flag, error in communication, enabling or disabling of certain peripherals or processes like cell balancing, data logging, data transmission/reception initiation and completion, charging, and discharging, and/or the like).
In yet another embodiment of the present disclosure, the warning is meant, for conditions, when the energy storage system (17) violates the critical threshold limits, but the fault condition does not persist, after a short period of time, when checked again. In such a case, the apparatus (10) communicates to the VCU (18) and expects it to just inform a user, about the current fault, and not isolate the energy storage system (17), from the rest of the powertrain (18), so as to warn the user, to keep a check, without causing a sudden shutdown of the vehicle.
For example, if the temperature of the cells, in the energy storage system (17), exceeds 60 degrees Celsius, due to sudden demand of torque, but the pack is cooled efficiently enough that the cells, in the energy storage system (17), attain normal temperature again, in a few milliseconds, this situation does not require complete power down of the vehicle and an initial warning raised would suffice.
Discharging Mode (the vehicle is on the move):
The plurality of tracking members (12) is accessed, for cell voltage, cell temperature data, and any other auxiliary data, alongside the at least one ascertaining member (13). All recorded data are checked against the critical thresholds.
In case of no errors, the cells are checked for their current voltage levels, and subjected to passive balancing, whenever needed. The apparatus (10) is checked, for any existing faults, periodically. The at least one switching member (14) is made to connect, in a configuration, which connects the packs, for discharging.
Standby (the vehicle is ON but idle):
The plurality of tracking members (12) is accessed, for cell voltage, cell temperature data, and any other auxiliary data, alongside the at least one ascertaining member (13). All recorded data are checked against the critical thresholds.
In case of no errors, the cells are checked, for their current voltage levels, and subjected to passive balancing, whenever needed. The apparatus (10) is checked, for any existing faults, periodically. The at least one switching member (14) is in ON state.
Shutdown (the vehicle is in OFF state):
All the cell data are recorded, but it is ensured that the at least one switching member (14) is in OFF state.
In yet another embodiment of the present disclosure, the apparatus (10) immediately deactivates the at least one switching member (14) and cuts off power, to the remaining powertrain, when it detects any out-of-range: cell voltages, temperatures; charge levels; and/or pack currents, for a predetermined period of time.
The apparatus (10) reactivates, once the fault has been resolved, within a predetermined period of time. The vehicle is to be restarted, if the fault does not resolve, within the predetermined time frame. This guarantees protection, from fire risks, or other high voltage dangers. The safety shutdown is only performed, for maximum efficiency, if the current fault continues, even after a phase of current derating.
The out-of-range values refer to those, which do not fall, in the manufacturer's recommended operating range. For example, in case of NMC energy storage system, any cell: possessing a voltage of less than about 2.5 V or more than about 4.2 V; and/or possessing a temperature less than about 10 degree Celsius or more than about 60 degree Celsius; and/or discharging, at a rate of more than about 11.25 C; and/or charging, at more than about 1.05 C, is considered to be out-of-range.
In yet another embodiment of the present disclosure, the apparatus (10) works, at two different voltages, such as about 120 V and about 240 V. The maximum operational current of the apparatus (10) is about 200 A.
In yet another embodiment of the present disclosure, each tracking member, among the plurality of tracking members (12), is connected using daisy-chain topology.
No load testing and testing with a discharge load, were performed, to validate the efficiency of the disclosed apparatus (10).
No Load Testing:
The disclosed apparatus (10) was connected with the energy storage system (17). The positive terminals of each cell were connected with the plurality of tracking members (12), and the negative terminal of the most critical cell was connected with the plurality of tracking members (12), through the respective temperature sensing member. A person skilled in the art will appreciate the meaning of the phrase “most critical cell”.
The operation started with the configuring of the plurality of tracking members (12), for each of the packs, in the energy storage system (17). The at least one primary controller (11) communicated with the base tracking member (12a), among the plurality of tracking members (12), and commanded the base tracking member (12a), to activate the rest of the tracking members (12b, 12c, and 12d), among the plurality of tracking members (12), using a dedicated wakeup/differential voltage signal.
The addresses and configurations assigned, for each tracking member, among the plurality of tracking members (12), were read back, for verification; subsequently, data logging started. The at least one primary controller (11) sampled the data received, from the plurality of tracking members (12), thereby, recording all essential cell data. Said data was (or were) further communicated to an external device, using CAN, and stored, in the plurality of tracking members (12), for a limited number of cycles. The plurality of tracking members (12) withstood upto about 5 cycles of data writing.
 
Load Testing:
It was performed, by connecting the energy storage system (17) with the disclosed apparatus (10), to a resistive/inductive load, and allowing a set amount of discharge, through the same, over a period of time. The apparatus (10) was allowed, to log real-time cell data, while the energy storage system (17) actively charged and/or discharged.
The apparatus (10) periodically logged individual cell voltages, individual cell temperatures, pack current, cell impedances, SOC, SOH, etc., thereby, allowing testing additional critical fault scenarios, including over-current, overcharge, over-discharge, over-temperature, and erroneous communication, across the plurality of tracking members (12).
During passive balancing, the apparatus (10) takes into account the OCV (Open Circuit Voltage) of all the cells, in the energy storage system (17), and calculates the cell string, which needs balancing. The steps involved are as follows:
1. The voltages of all the cells, in the energy storage system (17), are recoded, by the apparatus (10);

2. After recording all the voltages, and arranging them, in decreasing order, the average of all cell voltages is calculated;

3. The voltage of each cell is compared with the average value, and the cells, for which difference in voltage is more than about 0.5 V, or the ones, which are expected to contain higher charge content, are accumulated, to create a separate array;

4. The above created array is again compared with the former average value, and the cells, which differ in voltage, from the average value, by about 0.1 V, are expected to have higher voltages and subjected to balancing; and

5. After the balancing is enabled, the average of current voltages is calculated again, and the comparison continues, to initiate another cycle of balancing.
The at least one ascertaining member (13) is responsible for calculating remaining cell capacity, after a discharge, and also cell capacity, at maximum allowable charge (i.e., charge released, from a fully charged cell, to a completely discharged level), using three major parameters: initial charge content of said each cell, in the energy storage system (17) and current depth of discharge; internal resistance of said each cell, in the energy storage system (17); and connected load and temperature of said each cell, in the energy storage system (17).
The apparatus (10) is configured to perform three major phases of operation, for example, charge, discharge, and relaxation period.
Initiating from the charge mode, the apparatus (10) enters into the relaxation period, after the charge current reduces, to a minimum set value. The at least one ascertaining member (13) enters the discharge mode, when the vehicle demands a discharge, but the discharge current of the apparatus (10) is insufficient and is below a minimum set threshold.
The apparatus (10) exits the discharge phase, when the discharge current exceeds a maximum allowable discharge current, from the pack, and enters the relaxation period, after discharge. At any time, during this phase, if charging is initiated, and the charging current exceeds a minimum required charging current defined, the charging phase is entered, and the above cycle continues.
The at least one ascertaining member (13) stores a pre-defined depth of discharge table, which is essentially a plot between the open circuit voltage (OCV) of a cell and the temperature of the cell. Said table is different, for cells of different chemistries. As the three major phases are entered, at first, the OCV readings are updated, in the at least one ascertaining member (13,) after an about 30 minutes relaxation phase, along with the depth of discharge (DOD) calculation.
Post this, the OCV readings are recorded, after every about 100 seconds. Given that the apparatus (10) already has a plot of OCV vs temperature, based on cell chemistry, corresponding to the OCV readings, depth of discharge values are calculated.
The disclosed apparatus (10) offers at least the following advantages: is of plug and play nature; is scalable, to higher voltages; is capable of powertrain voltage switching; is capable of powertrain derating; has tuneable fault thresholds, as per real-time pack health status; offers passive cell balancing ensuring maximum cell usable capacity; provides active battery charge level indications and periodic range estimation; and is capable of performing: individual cell voltage monitoring and temperature monitoring, and pack current monitoring, cell overvoltage/undervoltage detection, cell over-temperature/under-temperature detection, cell overcharge/discharge protection; and cell undercharge detection.
Implementation of the apparatus and/or method of the disclosure can involve performing or completing selected tasks manually, automatically, or a combination thereof. Further, according to actual instrumentation of the apparatus and/or method of the disclosure, several selected tasks could be implemented, by hardware, by software, by firmware, or by a combination thereof, using an operating system.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations and improvements, without deviating from the spirit and the scope of the disclosure, may be made, by a person skilled in the art. Such modifications, additions, alterations, and improvements, should be construed as being within the scope of this disclosure.

LIST OF REFERENCE NUMERALS
10 - Apparatus for Surveilling an Energy Storage System of a Vehicle or Apparatus
11 - At Least One Primary Controller
12 - Plurality of Tracking Members
12a - Base Tracking Member or First Tracking Member
12b, 12c, 12d - Rest of the Tracking Members
13 - At Least One Ascertaining Member
14 - At Least One Switching Member
15 - At Least One Power Supply Member
16 - Shunt Resistor
17 - Energy Storage System
17a - One Pack
17b - Another Pack
18 - Powertrain/Vehicle Control Unit
T - Temperature Sensing Member
V – Voltage Sensing Member
VL - Rest of the Powertrain
M1, M2, M3, and M4 - Swap-Enabling Members
C - Charging Circuit
D - Discharging Circuit , Claims:1. An apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, comprising:
a plurality of tracking members (12) that facilitates monitoring and logging of a plurality of parameters, of each cell, in said energy storage system (17), in real-time, with:
data sensed, by said plurality of tracking members (12), being transmitted to an at least a primary controller (11);
each tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12), being configured to interact with each cell, among a plurality of cells, of said energy storage system (17); and
said each tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12), being associated with other tracking members, with a first tracking member (12a) acting as a base tracking member;
a voltage sensing member (V) that is associated with said each cell, among said plurality of cells, with said voltage sensing member (V) being communicatively associated with a respective tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12), through a filtering member;
a temperature sensing member (T) that is associated with each pair of cells, among said plurality of cells, with said temperature sensing member (T) being communicatively associated with a respective tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12);
an at least a switching member (14) that is configured to allow a plurality of packs, in said energy storage system (17), to: switch between parallel connection and series connection; and connect with, and disconnect from, a powertrain (18), as per instructions, from said at least one primary controller (11), with:
said switching, between said parallel connection and said series connection being performed, depending on an operating mode of said energy storage system (17);
an at least an ascertaining member (13) that is communicatively associated with said energy storage system (17), through a shunt resistor (16), with said at least one ascertaining member (13) being configured to determine: State of Charge; State of Health; cell impedance; remaining capacity; and energy content, of said energy storage system (17);
said at least one primary controller (11) that is configured to log all data received, in real-time, from said plurality of tracking members (12) and said at least one ascertaining member (13), with said at least one primary controller (11) facilitating tracking, monitoring, and controlling, of said apparatus (10); and
an at least a power supply member (15) that supplies power to said apparatus (10).
2. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
said plurality of parameters monitored and logged, by said plurality of tracking members (12), includes voltage and temperature.
3. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
said each tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12), is assigned with a unique user-defined address, with said plurality of tracking members (12) communicating with each other, through differential pair mechanism.
4. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1 or claim 3, wherein:
said each tracking member (12a, 12b, 12c, or 12d), among said plurality of tracking members (12), interacting with a maximum of 16 cells that are connected in series.
5. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, claim 3, or claim 4, wherein:
communication between said at least one primary controller (11) and said plurality of tracking members (12) is established, through a single-ended Universal Asynchronous Receiver/Transmitter.
6. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein: said filtering member is a passive RF filter.
7. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein: said temperature sensing member (T) is a thermistor.
8. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein: said shunt resistor (16) is a 2 milliohms shunt resistor.
9. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
communication between said at least one primary controller (11) and said at least one ascertaining member (13) is established, through Inter Integrated Circuit communication.
10. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
said operating mode of said energy storage system (17) includes a charging mode and a discharging mode.
11. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
said at least one switching member (14) comprises a plurality of swap-enabling members (M1, M2, M3, and M4) that is divided, into two segments, with:
a plurality of swap-enabling members, in a first segment, being configured to allow said plurality of packs, to switch between said parallel connection and said series connection; and
a plurality of swap-enabling members, in a second segment, being configured to connect with, and disconnect from, said powertrain (18).
12. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1 or claim 11, wherein: said plurality of swap-enabling members (M1, M2, M3, and M4) is power MOSFETs.
13. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, wherein:
said apparatus (10) is configured with galvanic isolation, between components.
14. The apparatus for surveilling an energy storage system of a vehicle, which is configured to switch between two different voltages, during charging and discharging of said energy storage system, as claimed in claim 1, claim 5, claim 9, or claim 10, wherein said at least one primary controller (11) is configured to:
determine said operating mode of said energy storage system (17);
configure and address said plurality of tracking members (12);
handle data sampling and logging;
handle communication between a vehicle control unit (18) and said apparatus (10);
send cell data, to said VCU (18), and receive a required message stack back, from said VCU (18); and
detect faults and handle detected faults, by computing if cell parameters exceed safe operating ranges.