Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
POWER MANAGEMENT OF A BATTERY PACK

Applicant:
River Mobility Private Limited
A company based in India,
Having its address as:
No. 25/3, KIADB EPIP Zone, Seetharampalya, Hoodi Road, Mahadevapura, Whitefield, Bengaluru, Karnataka, India- 560048

The following specification describes the invention and the manner in which it is to be performed.
PRIORITY INFORMATION
The present application does not claim priority from any other application.

FIELD OF INVENTION
The present invention generally relates to batteries. More specifically, the present invention is related to power management in battery packs.
BACKGROUND OF THE INVENTION
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
In most implementations, battery management systems do not allow battery cells to go below a certain voltage level by using various strategies. Using such strategies, peripherals and on board secondary functionalities of an appliance are disabled. This is done to minimise sleep current of the system thereby, extending the ideal state time or vacation mode time of a system, such as an electric vehicle. Further, manufacturers can also be notified about the state of the battery before the battery goes into a deep discharge state i.e., when the voltage level of the battery goes below a predefined level. However, when the battery goes into the deep discharge state, the vehicle enters into a dead state having no communication or connectivity with on board peripherals and/or cloud network and hence, needs to be transported to a service centre for replacement of the battery.
The reason due to which the vehicle enters into the dead state has been described henceforth with reference to Figs. 1a through 1d and Fig. 2. In one conventional approach, a low side back to back common source architecture is used for power management in a battery pack, as illustrated in Fig. 1a. In such topology, two semiconductor elements, such as Field Effect Transistors (FETs) are connected back to back alongside a negative arm of the battery pack and operated in a common source topology in an electrical path used for supplying electrical power for charging of the battery pack and for supplying the electrical power from the battery pack to an electrical load.
In another conventional approach, a low side back to back common drain architecture is used for power management in a battery pack, as illustrated in Fig. 1b. In such topology, two semiconductor elements, such as FETs are connected back to back alongside a negative arm of the battery pack and operated in a common drain topology in an electrical path used for supplying electrical power for charging of the battery pack and for supplying the electrical power from the battery pack to an electrical load.
In yet another conventional approach, a high side back to back common source architecture is used for power management in a battery pack, as illustrated in Fig. 1c. In such topology, two semiconductor elements, such as FETs are connected back to back alongside a positive arm of the battery pack and operated in a common source topology in an electrical path used for supplying electrical power for charging of the battery pack and for supplying the electrical power from the battery pack to an electrical load.
In yet another conventional approach, a high side back to back common drain architecture is used for power management in a battery pack, as illustrated in Fig. 1d. In such topology, two semiconductor elements, such as FETs are connected back to back alongside a positive arm of the battery pack and operated in a common drain topology in an electrical path used for supplying electrical power for charging of the battery pack and for supplying the electrical power from the battery pack to an electrical load.
Therefore, the conventional approaches utilize a common charge-discharge path, as illustrated in Fig. 2. Such a common charge-discharge path is used for charging the battery pack from a power source and for supplying the electrical power from the battery pack to an electrical load. When the battery pack goes into the deep discharge state, one or more of the semiconductor elements are made inactive to prevent further discharge of the battery pack. With such inactivation of the semiconductor elements, an active electrical path for charging the battery pack becomes unavailable, and thus repairing of the battery pack is required.
Therefore, there remains a need for a system and a method for power management of a battery pack in an electrical appliance using which the battery pack could be charged even when the battery pack enters into a deep discharge state, and the need for transporting the electric vehicle to the service centre for either repairing the battery pack or battery replacement is eliminated.
OBJECTS OF THE INVENTION
A general objective of the invention is to provide separate electrical paths for charging and discharging of battery packs.
Another objective of the invention is to provide a mechanism for charging of battery packs when the battery packs enter into a deep discharge state.
SUMMARY OF THE INVENTION
This summary is provided to introduce aspects related to a system and a method for power management of a battery pack in an electrical appliance, and the aspects are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In one embodiment, a system for power management of a battery pack in an electrical appliance comprises a first semiconductor element connected in a first electrical path for charging the battery pack by a charging unit. The system further comprises a second semiconductor element connected in a second electrical path for supplying electrical power from the battery pack to an electrical load. The system further comprises a logic circuit for supplying the electrical power to the electrical load from one of the charging unit and the battery pack.
In one aspect, the logic circuit comprises an OR logic to perform a logical OR operation on power inputs received from the charging unit and the battery pack.
In one aspect, the logic circuit provides the electrical power to the electrical load from the battery pack when a voltage level of the battery pack is greater than a predefined voltage level, and from the charging unit when the voltage level of the battery pack is lower than the predefined voltage level.
In one aspect, the electrical power from the charging unit and the electrical power from the battery pack is provided to the electrical load via the second electrical path when a voltage level of the battery pack is greater than the predefined voltage level.
In one aspect, the voltage level of the battery pack lower than the predefined voltage level indicates a deep discharge state of the battery pack.
In one aspect, the system comprises a microcontroller configured to turn OFF the second semiconductor element when a voltage level of the battery pack is lower than a predefined voltage level.
In one aspect, the electrical load comprises one or more of a vehicle peripheral unit, a DC motor, and a motor controller.
In one aspect, the system further comprises a third semiconductor element connected between the first semiconductor element and the charging unit for preventing flow of reverse current from the battery pack towards the charging unit.
In one aspect, the first semiconductor element, the second semiconductor element, and the third semiconductor element is a Field Effect Transistor (FET).
In one aspect, the electrical appliance is an Electric Vehicle (EV).
In one embodiment, a method for power management of a battery pack in an electrical appliance comprises providing a first electrical path for charging the battery pack by a charging unit. The first electrical path is comprised of a first semiconductor element. The method further comprises providing a second electrical path for supplying electrical power from the battery pack to an electrical load. The second electrical path is comprised of a second semiconductor element. The method further comprises providing a logic circuit for supplying electrical power to the electrical load from one of the charging unit and the battery pack.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constitute a part of the description and are used to provide a further understanding of the present invention.
Fig. 1a illustrates a low side back to back common source architecture used for power management in a battery pack, in accordance with prior art.
Fig. 1b illustrates a low side back to back common drain architecture used for power management in a battery pack, in accordance with prior art.
Fig. 1c illustrates a high side back to back common source architecture used for power management in a battery pack, in accordance with prior art.
Fig. 1d illustrates a high side back to back common drain architecture used for power management in a battery pack, in accordance with prior art.
Fig. 2 illustrates a circuit diagram of a system utilizing a common charge-discharge path for power management in a battery pack, in accordance with prior art.
Fig. 3 illustrates a circuit diagram of a system for power management of a battery pack in an electrical appliance, in accordance with an embodiment of the present invention.
Fig. 4 illustrates a circuit diagram of a system for power management of a battery pack in an electrical appliance, in accordance with another embodiment of the present invention.
Fig. 5 illustrates a flow chart of a method of power management of a battery pack in an electrical appliance, in accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Each embodiment described in this disclosure is provided merely as an example or illustration of the present invention and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The present invention pertains to a system and a method for power management of a battery pack in an electrical appliance. Specifically, the present invention proposes usage of two electrical paths for the power management of the battery pack. A first electrical path also referred to as a charging path may be used for supplying electrical power from a power source, for example a charging unit to the battery pack. Additionally, a second electrical path also referred to as a discharging path may be used for supplying the electrical power from the battery pack to an electrical load. Usage of a separate electrical path eliminates interdependency of charging and discharging of the battery pack. The implementation proposed by the present invention becomes beneficial in situations where the voltage level of the battery pack becomes critically low, for example during a deep discharge state and the battery is no longer able to supply the electrical power to the electrical appliance, especially because the discharging path may be electrically broken. In such situations, the charging path could be used for charging the battery pack. Specific details related to operation of the implementation proposed by the present invention are described successively.
Fig. 3 illustrates a circuit diagram of a system for power management of a battery pack 302 in an electrical appliance, in accordance with an embodiment of the present invention. The system comprises a first electrical path (labelled as charging path) used for charging the battery pack 302 by a charging unit 304. The system further comprises a second electrical path (labelled as discharging path) for supplying electrical power from the battery pack 302 to an electrical load 306. Operation of the first electrical path and the second electrical path may be controlled through one or more semiconductor elements connected in the first electrical path and the second electrical path, respectively. With such electrical arrangement, charging of the battery pack 302 by the charging unit 304 and supply of the electrical power to the electrical load 306 from the battery pack 302 can be performed separately without relying on a single electrical path. This becomes advantageous especially in situations when there is a single electrical path available for charging and discharging of the battery pack 302 (as shown in Fig. 2) and such single electrical path is damaged or becomes electrically broken when the battery pack 302 enters into a deep discharge state. For example, during the deep discharge state of the battery pack 302, when a voltage level of the battery pack 302 is lower than a predefined voltage level, the second electrical path may be electrically broken to prevent further discharging of the battery pack 302. In such a situation, the battery pack 302 can be charged by supplying the electrical power from the charging unit 304 via the first electrical path.
Fig. 4 illustrates a circuit diagram of a system for power management of a battery pack 402 in an electrical appliance, in accordance with another embodiment of the present invention. The system may comprise a first electrical path for charging the battery pack 402 by a charging unit 404. A first semiconductor element 406 may be connected in the first electrical path. The first semiconductor element 406 may prevent overcharging of the battery pack 402 by electrically breaking the first electrical path when a voltage level of the battery pack 402 exceeds a particular value i.e., the battery pack 402 gets sufficiently charged. A third semiconductor element 408 may also be connected in the first electrical path for preventing flow of current from the battery pack 402 to the charging unit 404 and allowing flow of current only in another direction i.e., from the charging unit 404 to the battery pack 402.
The system may further comprise a second electrical path for supplying electrical power from the battery pack 402 to an electrical load 410. A second semiconductor element 412 may be connected in the second electrical path for controlling supply of the electrical power from the battery pack 402 to the electrical load 410. The electrical load 410 may include high power electronic elements. For example, in an Electric Vehicle (EV), the electrical load 410 may include a Direct Current (DC) motor, a motor controller, a Vehicle Control Unit (VCU), and lights. Similarly, the electrical load 410 may include other electronic elements depending on a type of the electrical appliance within which the system is connected. A fourth semiconductor element 414 may be connected in the second electrical path for limiting inrush current flowing towards the electrical load 410 during power-up operation.
The system may further comprise a logic circuit 416 for supplying the electrical power to the electrical load 410 from one of the battery pack 402 and the charging unit 404. In one implementation, the logic circuit 416 may be an OR logic. The OR logic may perform a logical OR operation on power inputs received from the battery pack 402 and the charging unit 404. The logic circuit 416 may provide the electrical power to the electrical load 410 from the battery pack 402 when a voltage level of the battery pack 402 is greater than the predefined voltage level. Further, the logic circuit 416 may provide the electrical power to the electrical load 410 from the charging unit 404 when the voltage level of the battery pack 402 is lower than the predefined voltage level i.e., in a deep discharge state of the battery pack 402. In a normal operating condition, when the electrical appliance such as the EV is powered ON and when the voltage level of the battery pack 402 is greater than the predefined voltage level, the electrical power from the battery pack 402 is provided to the electrical load 410 via the second electrical path. Specifically, the electrical power is provided through activation of the second semiconductor element 412 and the fourth semiconductor element 414. Further, in the normal operating condition, a 12V output of a high power external DC-DC converter (not shown in Fig. 4) powers vehicle peripherals such as the VCU and a telematics unit. Alternatively, the electrical power from the battery pack 402 is provided to the electrical load 410 through the second semiconductor element 412, the logic circuit 416, and the DC-DC converter 420. In one implementation, the DC-DC converter 420 may provide an 11V output to power the VCU and the telematics unit.

When the battery pack 402 goes into the deep discharge state, the second semiconductor element 412 is inactivated to electrically break the second electrical path to prevent further discharging of the battery pack 402. The second semiconductor element 412 may be inactivated by a microcontroller 418 configured to sense the voltage level of the battery pack 402. The microcontroller 418 may derive electrical power from the logic circuit 416 post conditioning by one or more DC-DC converters 420, 422, for example buck converters. Electrical power conditioned by the one or more DC-DC converters 420, 422 may be used for powering one or more low power electronic elements of the electrical load 410, for example the VCU and the telematics unit. In such conditions, when the battery pack 402 is present into the deep discharge state and the second semiconductor element 412 is inactivated, the logic circuit 416 provides the electrical power to the electrical load 410 from the charging unit 404.
The first semiconductor element 406, the second semiconductor element 412, the third semiconductor element 408, and the fourth semiconductor element 414 may be implemented as Field Effect Transistors (FETs). In one implementation, the third semiconductor element 408 may be a diode. The FETs and the diode of appropriate specification may be used depending on current and voltage ratings of one or more of the battery pack 402, the charging unit 404, the electrical load 410, and the logic circuit 416.
In another embodiment, the electrical appliance may include battery operated devices such as laptops, personal computers, mobile devices, power tools, digital cameras, emergency power backup supplies.
Fig. 5 illustrates a flow chart of a method of power management of a battery pack in an electrical appliance, in accordance with another embodiment of the present invention. The order in which the flow diagram for power management of a battery pack in an electrical appliance is described should not be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the flow diagram or alternate methods. Additionally, individual blocks may be deleted from the flow diagram without departing from the spirit and scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware.
At step 502, it is determined that if a voltage level (Vcell_x) of a battery pack of an electrical appliance is greater than a predefined voltage level (V_min_th). When the voltage level (Vcell_x) of the battery pack is identified to be greater than the predefined voltage level (V_min_th), a discharging path is activated, at step 504, and normal operation is carried out, at step 506. Alternatively, at step 502, when the voltage level (Vcell_x) of the battery pack is identified to be lesser than the predefined voltage level (V_min_th), the discharging path is deactivated, at step 508. Successively, connection of charger with the electrical appliance is determined, at step 510. When the charger is identified to be connected, an output of a first buck converter (i.e., DC-DC converter 420 as shown in Fig. 4) is checked, at step 512. When the output of the first buck converter is identified to be proper, an output of a second buck converter (i.e., DC-DC converter 422 as shown in Fig. 4) is checked, at step 514. When the output of the second buck converter is identified to be proper, a microcontroller configured for activation-deactivation of charging-discharging paths is powered up, at step 516. Successively, a charger authentication message for the deep discharge stage of the battery pack is provided, at step 518, and the charging path is activated, at step 520. Thereafter, charging of the battery pack starts through the charging path, at step 522.
In view of the above provided embodiments and their explanations, it is evident that the present invention provides usage of two electrical paths, specifically a charging path and a discharging path for the power management of a battery pack. The charging path could be used for charging the battery pack even when the battery pack is present in a deep discharge state.
Although implementations of system for power management of a battery pack has been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations of system for power management of a battery pack. , Claims:WE CLAIM:
1. A system for power management of a battery pack (302, 402) in an electrical appliance, the system comprising:
a first semiconductor element (406) connected in a first electrical path for charging the battery pack (302, 402) by a charging unit (304, 404);
a second semiconductor element (412) connected in a second electrical path for supplying electrical power from the battery pack (302, 402) to an electrical load (306, 410); and
a logic circuit (416) for supplying the electrical power to the electrical load (306, 410) from one of the charging unit (304, 404) and the battery pack (302, 402).

2. The system as claimed in claim 1, wherein the logic circuit (416) comprises an OR logic to perform a logical OR operation on power inputs received from the charging unit (304, 404) and the battery pack (302, 402).

3. The system as claimed in claim 2, wherein the logic circuit (416) provides the electrical power to the electrical load (306, 410) from the battery pack (302, 402) when a voltage level of the battery pack (302, 402) is greater than a predefined voltage level, and from the charging unit (304, 404) when the voltage level of the battery pack (302, 402) is lower than the predefined voltage level.

4. The system as claimed in claim 1, wherein the electrical power from the battery pack (302, 402) is provided to the electrical load (306, 410) via the second electrical path when a voltage level of the battery pack (302, 402) is greater than a predefined voltage level.

5. The system as claimed in claim 3, wherein the voltage level of the battery pack (302, 402) lower than the predefined voltage level indicates a deep discharge state of the battery pack (302, 402).
6. The system as claimed in claim 1, further comprising a microcontroller (418) configured to turn OFF the second semiconductor element when a voltage level of the battery pack (302, 402) is lower than a predefined voltage level.

7. The system as claimed in claim 1, wherein the electrical load (306, 410) comprises a vehicle peripheral unit.

8. The system as claimed in claim 1, wherein the electrical load (306, 410) comprises a DC motor and a motor controller.

9. The system as claimed in claim 1, further comprising a third semiconductor element (408) connected between the first semiconductor element (406) and the charging unit (304, 404) for preventing flow of reverse current from the battery pack (302, 402) towards the charging unit (304, 404).

10. The system as claimed in claim 1, wherein the first semiconductor element (406), the second semiconductor element (412), and the third semiconductor element (408) is a Field Effect Transistor (FET).

11. The system as claimed in claim 1, wherein the electrical appliance is an Electric Vehicle (EV).

12. A method for power management of a battery pack (302, 402) of an electrical appliance, the method comprising:
providing a first electrical path for charging the battery pack (302, 402) by a charging unit (304, 404), wherein the first electrical path is comprised of a first semiconductor element (406);
providing a second electrical path for supplying electrical power from the battery pack (302, 402) to an electrical load (306, 410), wherein the second electrical path is comprised of a second semiconductor element (412); and
providing a logic circuit (416) for supplying electrical power to the electrical load (306, 410) from one of the charging unit (304, 404) and the battery pack (302, 402).

13. The method as claimed in claim 12, wherein the logic circuit (416) comprises an OR logic to perform a logical OR operation on power inputs received from the charging unit (304, 404) and the battery pack (302, 402).

14. The method as claimed in claim 13, wherein the logic circuit (416) provides the electrical power to the electrical load (306, 410) from the battery pack (302, 402) when a voltage level of the battery pack (302, 402) is greater than a predefined voltage level, and from the charging unit (304, 404) when the voltage level of the battery pack (302, 402) is lower than the predefined voltage level.

15. The method as claimed in claim 12, wherein the electrical power from the battery pack (302, 402) is provided to the electrical load (306, 410) via the second charging path when a voltage level of the battery pack (302, 402) is greater than a predefined voltage level.

16. The method as claimed in claim 14, wherein the voltage level of the battery pack (302, 402) lower than the predefined voltage level indicates a deep discharge state of the battery pack (302, 402).