Description:TECHNICAL FIELD
[0001] The present disclosure relates to liquid-cooled battery packs in a vehicle. In particular, the present disclosure provides a system and a method for reducing thermal gradients in a battery pack of a vehicle, for example, an electric vehicle (EV).

BACKGROUND
[0002] Generally, liquid cooling is widely used for cooling a battery pack of an electric vehicle. A liquid cooling system of the battery pack may include an air-cooling system to improve the cooling performance. The liquid cooling system may regulate temperature of the battery pack, and perform thermal management in the battery pack of the electric vehicle using cooling loops containing liquid coolants, for example, ethylene glycol. An electric pump in the liquid cooling system may circulate the liquid coolants through the battery pack to cool the battery pack. However, downstream portions of the battery pack may wind up hotter than upstream portions of the battery pack, as the coolants heat up in a course of its flow. Therefore, this leads to thermal gradients in the battery pack, differential ageing of cells within the battery pack, and voltage imbalances in the battery pack.
[0003] In conventional liquid cooling systems, heat generated by the cells within the battery pack may be dissipated into the coolants flowing through one or more channels across a length and a breadth of the battery pack. However, the temperature of the coolant rises as the coolant flows onwards and picks up the heat from the cells within the battery pack. Therefore, this results in non-uniformity in the temperature of the battery pack, and differential performance and ageing of the cells within the battery pack, which may be potentially disastrous for the battery pack in a long-term.
[0004] Further, the conventional liquid cooling systems may mitigate the temperature rise of the coolant, and the thermal gradients of the battery pack by increasing the coolant flow rates using a larger (i.e., pricier) pump and/or greater pumping power. Therefore, this results in parasitic losses in the liquid cooling systems.
[0005] There is, therefore, a need for a system and a method thereof for reducing thermal gradients in the battery pack of the vehicle in a cost-effective manner by overcoming the deficiencies in the prior art(s).

OBJECTS OF THE PRESENT DISCLOSURE
[0006] A general object of the present disclosure is to provide a system and a method for reducing thermal gradients in a battery pack of a vehicle, for example, an electric vehicle (EV) in an efficient and a cost-effective manner.
[0007] An object of the present disclosure is to provide a system that includes secondary channels formed by branching out and branching in primary channels arranged in a battery pack of a vehicle.
[0008] Another object of the present disclosure is to provide a system that includes secondary channels to reroute a portion of an incoming fluid flowing through primary channels to the secondary channels to reduce thermal gradients in a battery pack.
[0009] Another object of the present disclosure is to provide a system that reduces a flow rate of an incoming fluid near an upstream portion of a battery pack and increases a flow rate of the incoming fluid at a downstream portion of the battery pack.
[0010] Another object of the present disclosure is to provide a system that maintains thermal spread in a battery pack by reducing thermal gradients in the battery pack.

SUMMARY
[0011] Aspects of the present disclosure relate to liquid-cooled battery packs in a vehicle. In particular, the present disclosure provides a system and a method for reducing thermal gradients in a battery pack of a vehicle, for example, an electric vehicle (EV).
[0012] In an aspect, the present disclosure describes a system for reducing thermal gradients in a battery pack of a vehicle. The system includes one or more inlets through which an incoming fluid flows into the battery pack, and one or more outlets arranged on same sides or opposite sides of the one or more inlets. The system includes one or more primary channels arranged in the battery pack and associated with the one or more inlets and the one or more outlets to allow the incoming fluid to flow through the one or more primary channels. The system includes one or more secondary channels operatively connected to the one or more primary channels, and formed by branching out and branching in the one or more primary channels. The one or more secondary channels reroute at least a portion of the incoming fluid flowing through the one or more primary channels to the one or more secondary channels to reduce the thermal gradients in the battery pack.
[0013] In some embodiments, the one or more secondary channels may be arranged to reduce a flow rate of the incoming fluid near an upstream portion of the battery pack and increase the flow rate of the incoming fluid at a downstream portion of the battery pack.
[0014] In some embodiments, the one or more secondary channels may be arranged to increase heat dissipation of a portion of the battery pack adjacent to the downstream portion by increasing the flow rate of the incoming fluid at the downstream portion.
[0015] In some embodiments, the one or more secondary channels may maintain thermal spread in the battery pack by reducing the thermal gradients.
[0016] In some embodiments, the one or more secondary channels may be formed by branching out and branching in the one or more primary channels arranged in one of a linear arrangement or a serpentine arrangement.
[0017] In some embodiments, the one or more secondary channels may be formed at or near the one or more inlets by branching out an upstream tubing of the one or more inlets and branching in the one or more primary channels.
[0018] In some embodiments, the one or more secondary channels may be formed along the one or more primary channels arranged in between one or more cells of the battery pack to perform direct cooling of the battery pack.
[0019] In some embodiments, the one or more secondary channels may be formed along the one or more primary channels arranged in a clod plate in a surface below one or more cells of the battery pack to perform indirect cooling of the battery pack.
[0020] In some embodiments, one or more valves may be fitted to the one or more secondary channels to regulate a flow rate of the fluid entering the one or more secondary channels.
[0021] In an aspect, the present disclosure describes a method for reducing thermal gradients in a battery pack of a vehicle. The method includes arranging one or more inlets in the battery pack, where an incoming fluid flows through the one or more inlets into the battery pack. The method includes arranging one or more outlets on same sides or opposite sides of the one or more inlets. The method includes allowing the incoming fluid to flow through one or more primary channels associated with the one or more inlets and the one or more outlets. The method includes forming one or more secondary channels by branching out and branching in the one or more primary channels, and rerouting at least a portion of the incoming fluid flowing through the one or more primary channels to the one or more secondary channels to reduce the thermal gradients in the battery pack.
[0022] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0024] FIG. 1A illustrates an example block diagram of a system for reducing thermal gradients in a battery pack of an Electric Vehicle (EV), according to embodiments of the present disclosure.
[0025] FIG. 1B illustrates an exemplary isometric view of a system for reducing thermal gradients in a battery pack of an EV, according to embodiments of the present disclosure.
[0026] FIGs. 2A and 2B illustrate exemplary representations depicting serpentine cooling ribbon type arrangement of primary channels in a battery pack, according to embodiments of the present disclosure.
[0027] FIGs. 3A and 3B illustrate exemplary representations depicting serpentine arrangement of primary channels in a cold plate of a battery pack, according to embodiments of the present disclosure.
[0028] FIGs. 4A and 4B illustrate exemplary representations for implementing straight path immersion cooling of a battery pack, according to embodiments of the present disclosure.
[0029] FIGs. 5A and 5B illustrate exemplary representations for implementing serpentine immersion cooling of a battery pack, according to embodiments of the present disclosure.
[0030] FIG. 6 illustrates a flow chart for implementing an example method for reducing thermal gradients in a battery pack of a vehicle, according to embodiments of the present disclosure.

DETAILED DESCRIPTION
[0031] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosures as defined by the appended claims.
[0032] Embodiments explained herein relate to liquid-cooled battery packs in a vehicle. In particular, the present disclosure provides a system and a method for reducing thermal gradients in a battery pack of a vehicle, for example, an electric vehicle (EV).
[0033] In an embodiment, the present disclosure describes a system for reducing thermal gradients in a battery pack of a vehicle. The system includes one or more inlets through which an incoming fluid flows into the battery pack, and one or more outlets arranged on same sides or opposite sides of the one or more inlets. The system includes one or more primary channels arranged in the battery pack and associated with the one or more inlets and the one or more outlets to allow the incoming fluid to flow through the one or more primary channels. The system includes one or more secondary channels operatively connected to the one or more primary channels, and formed by branching out and branching in the one or more primary channels. The one or more secondary channels reroute at least a portion of the incoming fluid flowing through the one or more primary channels to the one or more secondary channels to reduce the thermal gradients in the battery pack.
[0034] In an embodiment, the present disclosure describes a method for reducing thermal gradients in a battery pack of a vehicle. The method includes arranging one or more inlets in the battery pack, where an incoming fluid flows through the one or more inlets into the battery pack. The method includes arranging one or more outlets on same sides or opposite sides of the one or more inlets. The method includes allowing the incoming fluid to flow through one or more primary channels associated with the one or more inlets and the one or more outlets. The method includes forming one or more secondary channels by branching out and branching in the one or more primary channels, and rerouting at least a portion of the incoming fluid flowing through the one or more primary channels to the one or more secondary channels to reduce the thermal gradients in the battery pack.
[0035] Various embodiments of the present disclosure will be explained in detail with respect to FIGs. 1-6.
[0036] FIGs. 1A and 1B illustrate an example block diagram (100A) and an exemplary isometric view (100B) of a system (120) for reducing thermal gradients in a battery pack of an EV, according to embodiments of the present disclosure.
[0037] With reference to FIGs. 1A and 1B, the system (120) may include one or more inlets (102), one or more outlets (104), one or more primary channels (106), one or more secondary channels (108), intermediate points (110), and other component(s) (112). The other component(s) may include valves, separators, and the like.
[0038] In an embodiment, the battery pack of the EV may be integrated with the one or more inlets (102). An incoming fluid may be allowed to flow into the battery pack through the one or more inlets (102).
[0039] In an embodiment, the battery pack may be integrated with the one or more outlets (104). In an embodiment, the one or more outlets (104) may be arranged on same sides of the one or more inlets (102). In another embodiment, the one or more outlets (104) may be arranged on opposite sides of the one or more inlets (102). The one or more outlets (104) may be arranged to allow the egress of the fluid from the battery pack.
[0040] In an embodiment, the one or more primary channels (106) may be arranged in the battery pack. The one or more primary channels (106) may be associated with the one or more inlets (102) and the one or more outlets (104) to allow the incoming fluid to flow through the one or more primary channels (106). In an embodiment, the one or more primary channels (106) may be arranged in a linear arrangement. In another embodiment, the one or more primary channels (106) may be arranged in a serpentine arrangement.
[0041] In an embodiment, the one or more secondary channels (108) may be operatively connected to the one or more primary channels (106). The one or more secondary channels (108) may be formed by branching out and branching in the one or more primary channels (106). The branching out and branching in portions of the one or more primary channels (106) may be known as the intermediate points (110). The intermediate points (110) may act as connection points between the one or more primary channels (106) and the one or more secondary channels (108).
[0042] In an embodiment, the one or more secondary channels (108) may be provided to reroute at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108) to reduce the thermal gradients in the battery pack.
[0043] In an embodiment, the one or more secondary channels (108) may be arranged to reduce a flow rate of the incoming fluid near an upstream portion of the battery pack and increase the flow rate of the incoming fluid at a downstream portion of the battery pack. In an embodiment, the upstream portion of the battery pack may be a portion of the battery pack adjacent to where the one or more primary channels (106) branch out to form the one or more secondary channels (108) at the intermediate point (110) and the downstream portion of the battery pack may be a portion of the battery pack adjacent to where the one or more secondary channels (108) branch into the one or more primary channels (106) at the intermediate point (110). The increase in the flow rate of the fluid at the downstream portion is when compared to the flow rate of the fluid in the one or more primary channels (106) after branching out at the intermediate point (110). The flow rate of the fluid in the one or more primary channels (106) may remain the same before the branching out and branching in of the one or more secondary channels (108). The upstream portion of the battery pack may wind up being slightly warmer, because it gets lesser coolant flow to take its heat away. The flow rate at each successive junction of the battery pack may be cooled due to an influx of unheated coolant. Therefore, this results in enhanced heat dissipation capability for the downstream portions of the battery pack and downstream battery temperatures that are lower than a default single channel system. Due to higher upstream temperatures and lower downstream temperatures compared to the default system, the thermal gradient along a flow path may be reduced.
[0044] In an embodiment, the one or more secondary channels (108) may be arranged to increase heat dissipation of a portion of the battery pack adjacent to the downstream portion by increasing the flow rate of the incoming fluid at the downstream portion.
[0045] In an embodiment, the one or more secondary channels (108) may be utilized to maintain thermal spread in the battery pack by reducing the thermal gradients in the battery pack.
[0046] In an embodiment, the one or more secondary channels (108) may be formed at, near, or closer to the one or more inlets (102) by branching out an upstream tubing of the one or more inlets (102) and branching in the one or more primary channels (106).
[0047] In an embodiment, the one or more secondary channels (108) may be formed along the one or more primary channels (106) immersed into or arranged in between one or more cells of the battery pack. The system (120) may perform direct cooling of the battery pack by immersing or arranging the one or more primary channels (106) in between the one or more cells of the battery pack.
[0048] In an embodiment, the one or more secondary channels (108) may be formed along the one or more primary channels (106) arranged in a surface below the one or more cells of the battery pack. The system (120) may perform indirect cooling of the battery pack by arranging the one or more primary channels (106) in a surface below the one or more cells of the battery pack.
[0049] In an embodiment, one or more valves (for example, 112) may be affixed to the one or more secondary channels (108). The one or more valves may be utilized to regulate a flow rate of the incoming fluid in the one or more secondary channels (108).
[0050] The system (120) may be implemented irrespective of the channel shape (e.g., linear, serpentine, etc.) and the sidedness of the one or more inlets (102) and the one or more outlets (104) on the battery pack.
[0051] FIGs. 2A and 2B illustrate exemplary representations (200A, 200B) depicting serpentine cooling ribbon type arrangement of primary channels in a battery pack, according to embodiments of the present disclosure.
[0052] With reference to FIGs. 2A and 2B, one or more primary channels (106) may be arranged in a serpentine cooling ribbon type arrangement. The one or more primary channels (106) may be immersed into or arranged in between one or more cells of the battery pack to achieve direct cooling of the battery pack. One or more secondary channels (108) may be formed at, near, or closer to the one or more inlets (102) by branching out the one or more primary channels (106) and branching in the one or more primary channels (106).
[0053] The one or more secondary channels (108) may be implemented to reroute at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108). Therefore, this reduces a flow rate of the incoming fluid near an upstream portion of the battery pack and increases the flow rate of the incoming fluid at a downstream portion of the battery pack to reduce the thermal gradients in the battery pack.
[0054] FIGs. 3A and 3B illustrate exemplary representations (300A, 300B) depicting serpentine arrangement of primary channels in a cold plate of a battery pack, according to embodiments of the present disclosure.
[0055] With reference to FIGs. 3A and 3B, one or more primary channels (106) may be arranged in a serpentine arrangement. The one or more primary channels (106) may be arranged in a cold plate of the battery pack. In some embodiments, the cold plate may be placed in a surface below the one or more cells of the battery pack. Therefore, this helps in achieving indirect cooling of the battery pack.
[0056] One or more secondary channels (108) may be formed by branching out the one or more primary channels (106) and branching in the one or more primary channels (106). The one or more secondary channels (108) may be implemented to reroute at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108) via intermediate points (110). The intermediate points (110) may be a branching out portion and a branching in portion of the one or more primary channels (106). Therefore, this helps in reducing a flow rate of the incoming fluid near an upstream portion of the battery pack and increasing the flow rate of the incoming fluid at a downstream portion of the battery pack to reduce the thermal gradients in the battery pack.
[0057] FIGs. 4A and 4B illustrate exemplary representations (400A, 400B) for implementing straight path immersion cooling of a battery pack, according to embodiments of the present disclosure.
[0058] With reference to FIGs. 4A and 4B, one or more primary channels (106) may be arranged in a linear arrangement or as a straight path. The one or more primary channels (106) may be immersed into or arranged in between cells of the battery pack. An upstream tubing of coolant entry ports or the one or more inlets (102) may be branched out into one or more secondary channels (1084) that re-enter the battery pack at one or more intermediate points (110) along a flow path. The flow path may be linear, serpentine, or any other suitable configuration, and the one or more inlets (102) and the one or more outlets (104) may be on the same sides or opposite sides of the battery pack.
[0059] The one or more secondary channels (108) may be implemented to increase heat dissipation of a portion of the battery pack adjacent to the downstream portion by increasing the flow rate of the incoming fluid at the downstream portion. Therefore, this helps in reducing the thermal gradients and maintaining thermal spread in the battery pack.
[0060] FIGs. 5A and 5B illustrate exemplary representations (500A, 500B) for implementing serpentine immersion cooling of a battery pack, according to embodiments of the present disclosure.
[0061] With reference to FIGs. 5A and 5B, one or more primary channels (106) may be arranged in a serpentine arrangement or as a cooling ribbon type arrangement. The one or more primary channels (106) may be immersed into or arranged in between cells of the battery pack. The one or more secondary channels (108) may be formed by branching out an upstream tubing of one or more inlets (102) or the one or more primary channels (106) and branching in the one or more primary channels (106) to re-enter the battery pack. Therefore, this helps in cooling the battery pack by rerouting at least a portion of an incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108).
[0062] FIG. 6 illustrates a flow chart for implementing an example method (600) for reducing thermal gradients in a battery pack of a vehicle, according to embodiments of the present disclosure.
[0063] With reference to FIG. 6, at step 602, the method (600) may include arranging one or more inlets (102) in a battery pack. An incoming fluid may be allowed to flow through the one or more inlets (102) into the battery pack.
[0064] At step 604, the method (600) may include arranging one or more outlets (104) on same sides or opposite sides of the one or more inlets (102).
[0065] At step 606, the method (600) may include allowing the incoming fluid to flow through one or more primary channels (106) associated with the one or more inlets (102) and the one or more outlets (104).
[0066] At step 608, the method (600) may include forming one or more secondary channels (108) by branching out and branching in the one or more primary channels (106).
[0067] At step 608, the method (600) may include rerouting at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108) to reduce the thermal gradients in the battery pack.
[0068] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the disclosure is determined by the claims that follow. The disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the present disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0069] The present disclosure reduces thermal gradients in a battery pack of a vehicle, for example, an electric vehicle (EV) in an efficient and a cost-effective manner.
[0070] The present disclosure provides a system that includes secondary channels formed by branching out and branching in primary channels arranged in a battery pack of a vehicle.
[0071] The present disclosure provides a system that includes secondary channels to reroute a portion of an incoming fluid flowing through primary channels to the secondary channels to reduce thermal gradients in a battery pack.
[0072] The present disclosure provides a system that reduces a flow rate of an incoming fluid near an upstream portion of a battery pack and increases a flow rate of the incoming fluid at a downstream portion of the battery pack.
[0073] The present disclosure provides a system that maintains thermal spread in a battery pack by reducing thermal gradients in the battery pack.

List of References:
System (120)
Inlets (102)
Outlets (104)
Primary Channel(s) (106)
Secondary Channel(s) (108)
Intermediate Point(s) (110)
Valves (112)

, Claims:1. A system (120) for reducing thermal gradients in a battery pack of a vehicle, the system (120) comprising:
one or more inlets (102) through which an incoming fluid flows into the battery pack;
one or more outlets (104) arranged on same sides or opposite sides of the one or more inlets (102);
one or more primary channels (106) arranged in the battery pack and associated with the one or more inlets (102) and the one or more outlets (104) to allow the incoming fluid to flow through the one or more primary channels (106); and
one or more secondary channels (108) operatively connected to the one or more primary channels (106), and formed by branching out and branching in the one or more primary channels (106), wherein the one or more secondary channels (108) reroute at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108) to reduce the thermal gradients in the battery pack.

2. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) are arranged to reduce a flow rate of the incoming fluid near an upstream portion of the battery pack and increase the flow rate of the incoming fluid at a downstream portion of the battery pack.

3. The system (120) as claimed in claim 2, wherein the one or more secondary channels (108) are arranged to increase heat dissipation of a portion of the battery pack adjacent to the downstream portion by increasing the flow rate of the incoming fluid at the downstream portion.

4. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) maintain thermal spread in the battery pack by reducing the thermal gradients.

5. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) are formed by branching out and branching in the one or more primary channels (106) arranged in one of: a linear arrangement, or a serpentine arrangement.

6. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) are formed at or near the one or more inlets (102) by branching out an upstream tubing of the one or more inlets (102) and branching in the one or more primary channels (106).

7. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) are formed along the one or more primary channels (106) immersed into or arranged in between one or more cells of the battery pack to perform direct cooling of the battery pack.

8. The system (120) as claimed in claim 1, wherein the one or more secondary channels (108) are formed along the one or more primary channels (106) arranged in a cold plate in a surface below one or more cells of the battery pack to perform indirect cooling of the battery pack.

9. The system (120) as claimed in claim 1, comprising one or more valves (112) fitted to the one or more secondary channels (108) to regulate a flow rate of fluid entering the one or more secondary channels (108).

10. A method (600) for reducing thermal gradients in a battery pack of a vehicle, the method comprising:
arranging one or more inlets (102) in the battery pack, wherein an incoming fluid flows through the one or more inlets (102) into the battery pack;
arranging one or more outlets (104) on same sides or opposite sides of the one or more inlets (102);
allowing the incoming fluid to flow through one or more primary channels (106) associated with the one or more inlets (102) and the one or more outlets (104);
forming one or more secondary channels (108) by branching out and branching in the one or more primary channels (106); and
rerouting at least a portion of the incoming fluid flowing through the one or more primary channels (106) to the one or more secondary channels (108) to reduce the thermal gradients in the battery pack.