BATTERY PACK FOR ONE VEHICLE

Abstract

A battery pack (100) includes a plurality of cells (102) arranged in a combination of series and parallel arrangements by a plurality of bus bars (104); and a plurality of safety switches (106) coupled between the cells (102S) of the plurality of cells (102), which are connected to a corresponding one of the plurality of bus bars (104). The plurality of safety switches (106) are configured to electrically isolate the corresponding cells (102S) from the bus bar when the cell (102) ceases to function or in undesirable situations that may lead to thermal runaway of the battery pack (100).The safety switches (106) are MOSFETs provided on a circuit board arranged in the respective cells (102S) to interrupt a circuit between a terminal (108) of the cell and the corresponding electrode (120) when a signal is received via a control terminal (112) provided on the cell (102S).

Description

TECHNICAL FIELDThe present disclosure relates generally to the technical field of batteries in vehicles. In particular, a simple, compact and efficient battery pack for a vehicle is being directed that electrically isolates the cells from a power rail in adverse situations.BACKGROUNDElectric vehicles are enjoying great popularity due to their environmental friendliness and potential for reducing greenhouse gas emissions. A decisive component of an e-vehicle is its battery system, which is responsible for storing and supplying electrical energy for driving the vehicle. These battery systems generally consist of numerous individual cells which are arranged in a specific configuration. The cells within the battery are interconnected by bus bars and form a series and parallel network to achieve the desired voltage and current parameters.However, the networked system presents a challenge in that a single non-functioning cell may render the entire battery pack unusable, possibly resulting in a full stop of the vehicle. Any external or internal malfunction may result in individual cells or cell sets within a battery pack being shorted or broken. Internal malfunctions may be cell aging, damage, overheating, overvoltage, undervoltage, and the like, while external malfunctions may result in a vehicle crash. In such situations, it would be advantageous if the battery pack cell topology could be altered to provide a usable battery pack with limited current and voltage.Efforts have been made in the art to meet the above-mentioned requirement by providing a mechanism that allows control over each individual cell. For example, US2022334192A1 discloses a battery pack having a plurality of sensors and switches. Each of the sensors and switches is connected in series with a bus bar connection, the sensors providing an indication of current in a corresponding bus bar connection, and the switches switching on / off current flow through the bus bar connection. The operation of the switches is coordinated to isolate a cell within a battery module. For example, all switches connecting a defective cell may be opened around each cell to enable isolation of the cells.While the cited reference discloses a battery pack having a mechanism for isolating individual cells, it is possible to provide a more efficient and compact arrangement for isolating particular cells in a battery pack.There is therefore a need for a simple, compact and efficient solution for isolating individual battery cells in a battery pack.OBJECT OF THE PRESENT DISCLOSUREA general object of the present disclosure is to ensure availability of battery pack power even when one of the cells is no longer functional.An object of the present disclosure is to provide a simple, compact and efficient solution for the electrical isolation of non-functional cells.Another object of the present disclosure is to provide an efficient battery pack and corresponding battery management system that enables functioning cells to still generate power at the rated voltage even when some of the cells fail.Another object of the present disclosure is to provide an efficient battery pack that reduces the risk of a short circuit in the event of deformation of the bus bars due to extreme impact on the battery pack during an accident by isolating the cells from the bus bars.Another object of the present disclosure is to provide an efficient battery pack that provides cell-level safety.SUMMARYAspects of the present disclosure relate to the technical field of battery packs. In particular, a simple, compact, and efficient battery pack for a vehicle is being directed to electrically isolating non-functioning cells.In one aspect, the present disclosure provides a battery pack including a plurality of cells arranged in a combination of series and parallel arrangement across a plurality of bus bars. The battery pack includes a plurality of safety switches coupled between the cells of the plurality of cells that are connected to a corresponding bus bar of the plurality of bus bars.The plurality of safety switches are configured to electrically isolate the respective cells from the power rail. In one aspect, the plurality of safety switches are located within the respective cells between a positive terminal of the cell and the corresponding electrode.In one aspect, the cells with the safety switches may include a control terminal to receive a signal to actuate the safety switch.In one embodiment, the safety switch may be a MOSFET located on a printed circuit board within the corresponding cell.In one embodiment, the cells with the safety switches may comprise a housing. The housing may accommodate the circuit board in a round shape at a bottom of the housing.In an embodiment, the plurality of cells may be arranged in a plurality of sets. The cells of each set may be connected in series and connected to a set of power rails of the plurality of power rails.In an embodiment, only the outermost cell of the cell set connected to the corresponding bus bar may have the safety switch. The plurality of cell sets may be connected in parallel.One aspect of the disclosure relates to a battery management system for a battery pack that includes a plurality of safety switches. Each of the safety switches is configured within an outermost cell of a set of cells of a plurality of cells of the battery pack, the set of cells being connected in series, and the outermost cell being connected to a power rail. The safety switches are configured to isolate the corresponding cell from the power rail to which the cell is connected.The battery management system further includes a controller configured to monitor the state of the cells and connected to the plurality of safety switches.In one aspect, the controller is configured to actuate the safety switches when it is determined that one of the cells of the cell set is no longer operable to isolate the corresponding cell set to maintain the battery pack operable with the remaining cells.In an embodiment, the safety switch may be a MOSFET and configured on a printed circuit board within the corresponding cell.In an embodiment, the plurality of safety switches are located within the respective cells between a positive pole of the cell and the corresponding electrode.In one embodiment, the cells with the safety switches may also include a control terminal operatively coupled to the MOSFET configured on the circuit board and also connected to the control unit to receive a signal for actuating the safety switch.Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments, taken in conjunction with the accompanying drawings, in which like numerals represent like elements.BRIEF DESCRIPTION OF THE DRAWINGSThe accompanying drawings serve to further understand the present disclosure and form part of this description. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustrative purposes only and thus do not constitute a limitation of the present disclosure. FIG. 1A shows an exemplary schematic arrangement of the proposed battery pack with cells of different cell sets arranged in series, which sets are again connected in parallel, according to embodiments of the present invention. FIG. 1B shows an example schematic illustration of an alternative arrangement of cells in a battery pack, in which the cells of different cell sets are arranged in parallel and the sets are again connected in series.FIGS. 2A and 2B show exemplary schematic representations of details of a single cell with a safety switch according to an embodiment of the present invention.DETAILED DESCRIPTIONThe following is a detailed description of the embodiments of the disclosure illustrated in the accompanying drawings. The embodiments are so detailed as to clearly convey the disclosure. However, it is not intended to limit the predictable variations of embodiments by way of detail; rather, all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims are intended to be covered.The embodiments discussed herein relate to a battery pack and a battery management system for the disclosed battery pack. In one aspect, the disclosed battery pack and corresponding system are based on a battery cell (also referred to herein simply as a cell) that includes a safety switch to isolate the cell from the battery pack. In one aspect, the safety switch is integrated into the cell in a connection between a terminal, such as a positive pole, of the cell and a corresponding electrode, such as the cathode of the cell.In an embodiment, the safety switch may be a MOSFET that is operated based on a signal to open the connection between the terminal and the electrode. The MOSFET may be located on a printed circuit board accommodated in a housing of the corresponding cell, and a controller connected to the printed circuit board may be provided on the housing to operate the MOSFET.In another embodiment, the battery pack may include a plurality of cells arranged in multiple sets, wherein the cells of each set may be connected in series, and the sets themselves are connected in parallel to achieve the desired voltage and current parameters. With the above arrangement of cells within the battery pack, only an outermost cell of the series-connected cell set needs to be disconnected from the corresponding bus bar to isolate the entire cell set from the battery pack. In this way, the low power cells can also be isolated without compromising the battery pack's rated voltage; only the rated current is reduced, so that the battery pack can continue to be used for at least a portion of the power demand.In one embodiment, a battery management system (BMS) controller may be operatively coupled to the controller to isolate the cell set from the battery pack. Coupling the controller to the controller may also allow the BMS to perform diagnostic tests to identify malfunctioning cells. For example, the BMS can individually check the state of all cell sets by isolating all cell sets except the one whose state / power is being checked, and decide whether there is a low-power cell in the set. Additionally, the BMS may incorporate other sensors, such as temperature sensors, to detect adverse situations, such as heating cells, and upon detection of an adverse situation in a cell, isolate the corresponding cell set to prevent thermal outliers.Referring to FIG. 1A, where a proposed arrangement of cells in the disclosed battery pack has been disclosed, the battery pack 100 may include a plurality of battery cells, such as cells 102, the cells 102 being arranged in sets, such as sets 110S- 1, 110S- 2,..., etc., each set 110S having a number of series-connected cells 102 (accordingly, the set is collectively referred to as set 110S of series-connected cells). As will be understood by those skilled in the art, the number of cells 102 in each set 110S of series-connected cells 102 may be based on the rated voltage of the battery pack 100. For example, if each cell 102 has an output voltage of 1.2 volts, 10 cells 102 may be connected in series to obtain an output voltage of 12 volts.In another embodiment, as shown in FIG. 1A, the various sets 110S of series-connected terminals 102 may be connected in parallel with each other. To achieve a desired current of the battery pack 100. For example, if cells 102 have a rated current of 1 A, there may be 100 sets of series connected cells 102 for a rated current power of 100 A.Also shown in FIG. 1A are bus bars, such as a positive bus bar 104P and a negative bus bar 104N (collectively referred to herein as bus bars 104). The positive terminal of a corresponding outermost cell, designated as 102S, is connected to the positive bus bar 104P and the negative terminal of the other outermost cell is connected to the negative bus bar 104P.In one embodiment, the outermost cell 102S connected to a corresponding power rail 104 of each set 110S of series-connected cells may include a safety switch. It will be appreciated that opening the safety switch will result in the corresponding set 110S of series connected cells 102 being disconnected from the power rails 104.FIG. 1B shows another arrangement of cells 102 in a battery pack 100, wherein the cells 102 are first connected in parallel with the positive and negative bus bars 104 to form different sets of parallel connected sets, such as sets 110P- 1, 110P- 2, etc., wherein each set 110P includes a number of parallel connected cells 102 (accordingly, the set is collectively referred to as set 110P of parallel connected cells, and the sets 110S of series connected cells and the sets 110P of parallel connected cells are collectively referred to as sets 110), and the sets 110P of parallel connected cells may be again connected in series. As can be seen, each of the cells 102 is connected to a power rail 104, and the isolation of one of the cells 102 requires an independent safety switch for each cell 102. While the arrangement that requires a corresponding safety switch for each cell 102 may make the system expensive and complex, it offers the advantage that only one cell loses its performance when the cell is out of operation, as compared to the embodiment in Figure 1A where all cells 102 in the corresponding set 110 are lost.The cell 102S with a safety switch 106 may include a housing 114 and a control terminal 112 to receive a signal to actuate the safety switch 106.In one embodiment, the safety switch 106 may be a semiconductor switch, such as a MOSFET, that can open a circuit upon receipt of a signal. The MOSFET may be configured on a printed circuit board such that the MOSFET operates as a circuit breaking device for a circuit between a terminal of the cell 102S, e.g., a positive terminal 108, and the corresponding electrode 120, e.g., a cathode of the cell 102S.In an embodiment, the MOSFET may be located on a circuit board, such as circuit board 116, located within the corresponding cell 102S, e.g., at a bottom of the housing 114, as shown in FIG. 2B. The circuit board 116 may have a round shape to be accommodated in the cylindrical housing 114. The controller terminal 112 may also be connected to the circuit board 116 to allow the MOSFET to receive the signal supplied to the controller terminal 112.In one embodiment, the battery pack 100 may be operatively coupled to a control unit of the vehicle's battery management system (BMS). Further, the controller may be configured to sense the status of the cells 102 of the battery pack with respect to their non-performance and other parameters to detect the likelihood of occurrence of an undesirable situation, such as thermal runaway of the battery pack 100. The controller may be further configured to actuate the safety switches 106 to isolate the non-functional cells 102 / 102S or those cells likely to cause an undesirable situation. In an exemplary embodiment, the battery management system may be configured to monitor the voltage, electric current, pressure, and temperature within the cells 102S of the plurality of cells 102 such that the cells 102 operate within safe limits and prevent thermal runaway, short circuits, and excessive pressure buildup.In another exemplary embodiment, the battery pack 100 may include a cooling passage plate 118 (see FIG. 1B ) to support the cells 102S and the plurality of cells 102 such that the cells 102S with the plurality of cells 102 may be arranged in a plurality of sets 110 on the cooling passage plate 118. The cooling channel plate 118 may be configured to absorb the heat dissipated from the plurality of cells 102.In an exemplary embodiment, the controller of the proposed system may include one or more processor(s). The one or more processor(s) may be implemented as one or more microprocessor(s), microcomputers, microcontrollers, digital signal processors, central processing units, logic circuits, and / or any devices that manipulate data based on operating instructions. Among other capabilities, the one or more processor(s) is / are configured to fetch and execute computer readable instructions stored in a memory of the processing unit. The memory may store one or more computer readable instructions or routines that may be fetched and executed to create or share the data units via a network service. The memory may include any nonvolatile memory device, for example, a volatile memory such as RAM or a nonvolatile memory such as EPROM, flash memory, and the like.While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope of the invention. The scope of the invention is defined by the following claims. The invention is not limited to the described embodiments, variations, or examples included to enable a person of ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person of ordinary skill in the art.ADVANTAGES OF THE INVENTIONThe present invention provides a solution that ensures availability of battery pack power even when one of the cells is no longer functional.The present invention provides a simple, compact and efficient solution for electrically isolating non-functional cells.The present invention provides an efficient battery pack and corresponding battery management system that enables functional cells to still generate power at the rated voltage even when some of the cells fail.The present invention provides an efficient battery pack that reduces the risk of a short circuit in the event of bus bars deforming due to extreme impact on the battery pack during an accident by isolating the cells from the bus bars.The present invention provides an efficient battery pack that provides cell-level safety.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedUS 2022334192A1

[0004]

Claims

A battery pack for a vehicle, the battery pack (100) comprising: a plurality of cells (102) arranged in a combination of series and parallel arrangement across a plurality of bus bars (104); and a plurality of safety switches (106) coupled between the cells (102S) of the plurality of cells (102), wherein the cells are connected to a corresponding bus bar of the plurality of bus bars (104); wherein the plurality of safety switches (106) are configured to electrically isolate the corresponding cells (102S) from the bus bar, and wherein the plurality of safety switches (106) are arranged within the respective cells (102S) between a positive terminal (108) of the cell and the corresponding electrode (120).The battery pack (100) of claim 1, wherein the cells (102S) having the safety switches (106) include a control terminal (112) for receiving a signal to actuate the safety switch (106).The battery pack (100) of claim 2, wherein the safety switch (106) is a MOSFET configured on a circuit board (116) located within the corresponding cell (102S).The battery pack (100) according to claim 3, wherein the cells (102S) including the safety switches (106) include a case (114), and wherein the circuit board (116) has a round shape and is disposed at a bottom of the case (114).The battery pack (100) of claim 1, wherein the plurality of cells (102) are arranged in a plurality of sets (110), the cells of each set being connected in series and connected to a set of bus bars of the plurality of bus bars (104).The battery pack (100) of claim 6, wherein only an outermost cell (102S) of each of the sets (110) of cells (102) connected to the corresponding bus bar comprises the safety switch (106).The battery pack (100) of claim 7, wherein the plurality of sets (110) of the cells (102) are connected in parallel.A battery management system for a battery pack (100), the system comprising: a plurality of safety switches (106), each of the safety switches being configured within an outermost cell (102S) of a set of cells (102) of a plurality of cells (102) of the battery pack (100), the set of cells (102) being connected in series and the outermost cell (102S) being connected to a power rail (104), the safety switches (106) being configured to isolate the corresponding cell (102S) from the power rail (104) to which the cell (102) is connected; and a controller configured to monitor the state of the cells and operatively coupled to the plurality of safety switches (106); and wherein the controller is configured to actuate the safety switches (106) when it is detected that one of the cells of the cell set is no longer functional to isolate the corresponding cell set to allow the battery pack with the remaining cells (102) to remain functional.The system of claim 8, wherein the safety switch (106) is a MOSFET configured on a circuit board (116) located within the corresponding cell (102S).The system of claim 9, wherein: the plurality of safety switches (106) are disposed within the respective cells (102S) between a positive terminal (108) of the cell and the corresponding electrode (120); the cells (102S) with the safety switches (106) comprise a control terminal (112) operatively coupled to the MOSFET configured on the circuit board (116) and further coupled to the control unit to receive a signal to actuate the safety switch (106).

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