Battery Cell Cooling System for Electronic Vehicles

A battery cell cooling system includes a housing including an inlet configured to receive a coolant and an outlet configured to discharge the coolant, the housing defining a plurality of slots between the inlet and the outlet, each of the plurality of slots being spaced apart from adjacent slots, and a plurality of battery cells disposed in the plurality of slots, wherein the coolant is configured to flow from the inlet, through the spaces between plurality of slots, and to the outlet.

FIELD

The present disclosure relates generally to battery cell cooling systems for electronic vehicles.

BACKGROUND

Electronic vehicles (EVs) include batteries comprising multiple cells. During operation of the EV, the battery cells generate heat due to enthalpy changes, electrochemical polarization, and resistive heating inside the cell. If there is insufficient cooling of the battery cells, then serious problems may arise, including decrease in battery performance, reduced cell life, thermal runaway, etc. Accordingly, there are opportunities for improvements in current battery cell cooling systems for EVs.

SUMMARY

Implementations of the disclosure may include one or more of the following optional features. In some implementations, a battery cell cooling system includes a housing including an inlet configured to receive a coolant and an outlet configured to discharge the coolant, the housing defining a plurality of slots between the inlet and the outlet, each of the plurality of slots being spaced apart from adjacent slots, and a plurality of battery cells disposed in the plurality of slots, wherein the coolant is configured to flow from the inlet, through the spaces between plurality of slots, and to the outlet. This aspect may include one or more of the following optional features.

The coolant may directly contact the battery cells.

The battery cell cooling system may include a sleeve disposed in each of the plurality of slots, each sleeve being configured to receive one of the plurality of battery cells. The coolant may directly contact the sleeve, and heat may be transferred from the battery cell to the coolant through the sleeve. The battery cell cooling system may include thermal paste disposed between each battery cell and sleeve, and heat may be transferred from the battery cell to the coolant through the thermal paste and the sleeve.

The battery cell cooling system may include a seal configured to contain the coolant in the housing. The seal may be disposed around one of the battery cells to allow the coolant to directly contact the battery cell. The seal may extend around the periphery of the plurality of battery cells.

The battery cell cooling system may include a top coolant plate and a bottom coolant plate spaced from the top coolant plate, each of the coolant plates being configured to receive the plurality of battery cells. The coolant may be configured to be disposed between the top coolant plate and the bottom coolant plate. The battery cell cooling system may include a top securing plate spaced from the top coolant plate and a bottom securing plate spaced from the bottom coolant plate. Each of the plurality of battery cells may include a top lip configured to engage the top coolant plate and a bottom lip configured to engage the bottom coolant plate.

The coolant may be configured to contact the full circumference of each of the plurality of battery cells.

The battery cell cooling system may be configured to be incorporated into an electric vehicle.

The battery cell cooling system may be configured to be incorporated into a hybrid-electric vehicle.

The height of each of the plurality of battery cells may be greater than the height of each slot defined by the housing. Each of the plurality of battery cells may include a positive and negative terminal, and each positive and negative terminal may extend beyond the housing.

The coolant may be at least one of water, mono-ethylene glycol, and oil.

The plurality of sleeves may be cylindrical and the battery cells may be cylindrical.

The plurality of sleeves may be prismatic and the battery cells may be prismatic.

DETAILED DESCRIPTION

As electric vehicles (EVs) continue to rise in popularity, one of the primary concerns with this type of automobile is ensuring the battery cells do not overheat, which can lead to the battery cells entering thermal runaway, a reduction in the performance of the battery cells, and/or a reduction in the lifetime of the battery cells. Compared to traditional automobiles having combustion engines, EVs need different cooling systems to ensure the battery cells do not overheat. Many cooling systems for EV batteries only target a small section of each battery cell, e.g., the bottom or partial side of each cell. Additionally, reducing the number of components between the battery cells and the coolant may improve heat transfer. However, when the coolant is a liquid, proper precautions must be taken to ensure certain portions of the battery cells remain isolated from the liquid coolant.

Referring toFIGS.1-4, a cooling system100is generally shown. The cooling system100is configured to be installed in any suitable EV, including battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs). The cooling system100may also be configured for cylindrical and prismatic battery cells, although the figures only show cylindrical cells for illustrative purposes. The cooling system100includes a housing102having an inlet104and an outlet106. The inlet104includes an inlet passage104aconfigured to receive a coolant. Similarly, the outlet106includes an outlet passage106aconfigured to discharge a coolant. The coolant may be any suitable coolant, including water, ethylene glycol, oil, air, aromatics (e.g., diethyl benzene), aliphatics (e.g., polyalphaolefins), silicones (e.g., silicone oil), fluorocarbons (e.g., hydrofluoroethers, perfluorocarbon ethers), liquid metals, nanofluid (e.g., CuO nanoparticles in EG/water), and any combination of the foregoing.

The housing102is configured to receive a plurality of battery cells108. For example, as shown inFIG.3, the housing102defines a plurality of slots110sized to receive the plurality of battery cells108. In some implementations, each of the plurality of slots110receive a sleeve112that is sized to receive each of the battery cells108. The sleeve112may be integrally formed with the housing102or may be formed separately and subsequently attached to the housing102via soldering, brazing, welding, or any other suitable process.

Each of the battery cells108includes a positive terminal108a, a negative terminal108b, and an outer surface108c. As shown inFIG.1, in some implementations, the positive terminal108aextends beyond a top surface102aof the housing102and the negative terminal108bextends beyond a bottom surface102bof the housing102. There may be an intermediary material between the outer surface108cof each battery cell108and each sleeve112, such as glue, thermal paste, etc. The battery cells108may be any suitable shape, including cylindrical, prismatic (e.g., having a rectangular profile), etc. The battery cells108may be any suitable type of battery, including lithium-ion batteries, nickel-metal hydride batteries, lead-acid batteries, ultracapacitors, etc.

Referring toFIGS.1-4, the housing102defines a cavity114between each of the battery cells108and completely surrounding each of the battery cells108. That is, the complete circumference of each battery cell108is adjacent the cavity114. The cavity114is configured to receive the coolant. By surrounding each individual battery cell108, the coolant is able to contact a large surface area to increase heat transfer from the battery cells108to the coolant, thus improving performance and lifetime of the battery cells108. Additionally, such a configuration may reduce the risks of thermal runaway.

In alternative embodiments, for example, as shown inFIGS.5and6, the sleeve112may be omitted and a seal116may be implemented at or near the top surface102aand bottom surface102bto create a seal at the outer surface108cof each battery cell. The inlet104and the outlet106are omitted for clarity sake, and only a portion of the cooling system100is shown, but it should be understood that other features shown inFIGS.1-4are likewise present in this embodiment. The seal116and the outer surface108ccooperate with the housing102to define the cavity114that receives the coolant. In these implementations, the coolant directly contacts the outer surface108cof each battery cell108. This further improves heat transfer from the battery cells108to the coolant as there are no obstructions between the battery cell108and the coolant.

In another embodiment as shown inFIG.7, the cooling system100includes a pair of seals116that extend around multiple battery cells108. For example, the top seal116and the bottom seal116cooperate with the housing102to create a cavity that has an I-shaped profile with the top and bottom portions of the cavity114extending to the outer surface108cof each battery cell108and to each seal116, and the middle portion of the cavity114surrounding the outer surface108cof the battery cells108. The inlet104and the outlet106are omitted for clarity sake, and only a portion of the cooling system100is shown, but it should be understood that other features shown inFIGS.1-4are likewise present in this embodiment.

In another embodiment, as shown inFIG.8, the battery cells108include a pair of steps or lips118that cooperate with the seals116to define the cavities114between the seals116and the outer surfaces108cof the battery cells108. The steps118are portions of the battery cells108that have a larger circumference or perimeter than the slots110that receive the battery cells108. Additional seals120may be incorporated adjacent the steps118to ensure a proper seal is maintained. The inlet104and the outlet106are omitted for clarity sake, and only a portion of the cooling system100is shown, but it should be understood that other features shown inFIGS.1-4are likewise present in this embodiment.

In another embodiment, as shown inFIGS.9and10, the battery cells108may be received in sleeves112that include steps or lips122that engage a top seal116and a bottom seal116similar to the embodiment shown inFIG.8. The sleeves112may be formed of a polymer with additives to help with heat transfer. In some implementations, the seals116may be over-molded directly to the lip122with silicone or other suitable material to create a suitable seal as shown inFIG.10B. The inlet104and the outlet106are omitted for clarity sake, and only a portion of the cooling system100is shown, but it should be understood that other features shown inFIGS.1-4are likewise present in this embodiment.