BATTERY SYSTEM INCLUDING A PRESSURE VESSEL AND AN ONBOARD SYSTEM PRESSURIZING THE PRESSURE VESSEL

A battery system is provided including a battery pack including a battery housing and a plurality of battery cells stacked within the battery housing in a stacking direction. Each of the battery cells includes an anode current collector, an anode material on the anode current collector, a cathode current collector, a cathode material on the cathode current collector, and a solid-state electrolyte sandwiched between the anode material and the cathode material for transporting ions between the anode material and the cathode material. The battery system also includes a pressure vessel. The battery pack is inside of the pressure vessel, and the pressure vessel includes a gas inlet and a gas outlet.

TECHNICAL FIELD

The present disclosure relates generally to solid state electrolyte batteries and more specifically to packaging solid state electrolyte batteries for motor vehicles.

BACKGROUND

Solid state electrolyte battery cells require a different environment than liquid electrolyte batteries. Accordingly, there is a need for an improved battery enclosure

SUMMARY

A battery system is provided including a battery pack including a battery housing and a plurality of battery cells stacked within the battery housing in a stacking direction. Each of the battery cells includes an anode current collector, an anode material on the anode current collector, a cathode current collector, a cathode material on the cathode current collector, and a solid-state electrolyte sandwiched between the anode material and the cathode material for transporting ions between the anode material and the cathode material. The battery system also includes a pressure vessel. The battery pack is inside of the pressure vessel, and the pressure vessel includes a gas inlet and a gas outlet.

In examples, the battery system further includes a pressurization system for conveying compressed gas into the pressure vessel via the gas inlet to generate a force on the battery housing for maintaining uniform pressure on each battery cell in the stacking direction, the pressurization system including a gas inlet line feeding into the gas inlet of the pressure vessel and a gas outlet line exiting the gas outlet of the pressure vessel.

In examples, the pressurization system includes a check valve in the gas inlet line for allowing gas to flow into the gas inlet and preventing backflow from the gas inlet.

In examples, the pressurization system includes a control valve connectable downstream of a compressor, the control valve including a first outlet connectable to an input gas line of a condenser for supplying compressed gas to the condenser and a second outlet for supplying compressed gas to the gas inlet line.

In examples, the pressurization system includes a controller configured to control the control valve to control a flow rate into the gas inlet of the pressure vessel based on a specified temperature within the pressure vessel.

In examples, the pressurization system includes a pressure relief valve downstream from the gas outlet of the pressure vessel for regulating a pressure of the compressed gas within the pressure vessel.

In examples, the pressurization system includes a controller configured to control the pressure relief valve to control a pressure of the compressed gas within the pressure vessel based on a specified pressure.

In examples, the battery system further includes an inlet end cap plugging a first open end of the pressure vessel and sealingly surrounding the gas inlet, and an outlet end cap plugging a second open end of the pressure vessel and sealingly surrounding the gas outlet.

In examples, the battery system further includes electrical and/or data wires entering into the pressure vessel via the first open end by passing through the inlet end cap or entering into the pressure vessel via the second open end by passing through the outlet end cap.

In examples, the battery system further includes a heat exchanger inside the pressure vessel and in contact with the battery pack for cooling the battery cells.

In examples, the battery system further includes an inlet coolant line delivering coolant into the pressure vessel and into the heat exchanger via the first open end by passing through the inlet end cap or via the second open end by passing through the outlet end cap; and an outlet coolant line delivering coolant exiting the heat exchanger and out of the pressure vessel via the second open end by passing through the outlet end cap or via the first open end by passing through the inlet end cap.

An onboard system is also provided including the battery system, an HVAC system configured for absorbing heat from a cabin of the motor vehicle and producing heated compressed gas, and a pressurization system configured for receiving the heated compressed gas from the HVAC system and conveying the heated compressed gas into the pressure vessel via the gas inlet.

In examples, the HVAC system includes an evaporator within the cabin of the motor vehicle configured for absorbing heat from the cabin and evaporating the liquid refrigerant into gas; a compressor configured for compressing and heating the gas; and a condenser configured for cooling the heated gas compressed by the compressor and condensing the gas into a liquid.

In examples, the HVAC system further includes a dryer downstream from the pressure relief valve and configured for receiving liquid refrigerant from the condenser; and an expansion valve downstream of the dryer for regulating the flow of liquid refrigerant into the evaporator.

In examples, the pressurization system includes a control valve downstream of the compressor, the control valve including a first outlet connectable to an input gas line of the condenser for supplying the compressed gas to the condenser and a second outlet for supplying the compressed gas to the gas inlet of the pressure vessel.

In examples, the pressurization system includes a check valve in the gas inlet line for allowing gas to flow into the gas inlet and preventing backflow from the gas inlet.

In examples, the pressurization system includes a pressure relief valve for regulating a pressure of the gas within the pressure vessel, the pressure relief valve arranged such that the compressed gas exiting the pressure relief valve merges with the liquid refrigerant output by the condenser.

In examples, the onboard system further includes a heat exchanger inside the pressure vessel and in contact with the battery pack for cooling the battery cells; an inlet coolant line delivering coolant into the pressure vessel and into the heat exchanger via the first open end by passing through the inlet end cap or via the second open end by passing through the outlet end cap; and an outlet coolant line delivering coolant exiting the heat exchanger and out of the pressure vessel via the second open end by passing through the outlet end cap or via the first open end by passing through the inlet end cap.

In examples, the onboard system further includes a cooling loop providing coolant to the inlet coolant line and receiving coolant from the outlet coolant line, the cooling loop including a radiator and a pump, the coolant flowing from the outlet coolant line through the radiator to the pump, the pump configured for pumping the coolant into the heat exchanger via the inlet coolant line.

In examples, the cooling loop includes a heater for providing heat to a cabin heating system of the motor vehicle; a control valve coupled to the outlet coolant line, the control valve including a first outlet for supplying coolant to the radiator and a second outlet for supplying coolant to the heater; and a coolant line extending from the cabin heating system to the pump.

DETAILED DESCRIPTION

FIG.1shows a battery system10including a battery pack12including a battery housing14and a plurality of battery cells16, which are shown schematically within one of battery cells16stacked within the battery housing14in a stacking direction18. Each of the battery cells16includes an anode current collector20, an anode material22on the anode current collector20, a cathode current collector24, a cathode material26on the cathode current collector24, and a solid-state electrolyte28sandwiched between the anode material22and the cathode material26for transporting ions between the anode material22and the cathode material26.

Anode material26can be a lithium metal. Lithium metals forming the anode material26can include lithium iron phosphate (LFP), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO) and lithium manganese oxide (LMO).

Cathode material30can be lithium iron phosphate (LFP), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium titanate (LTO), nickel cobalt aluminum oxide (NCA) or nickel cobalt manganese (NCM).

The anode material22of each battery cell16expands in the stacking direction18during charging and contracts in the stacking direction18during discharging, which causes each of battery cells16to expand in the stacking direction18during charging and to contract in the stacking direction18during discharging. If battery cells16included liquid electrolytes, this expansion and contraction would not be an issue as liquid electrolyte penetrates both the cathode and anode materials. However, the rigid nature of solid-state electrolyte28can cause problems when anode material22expands and contracts due to the intercalation/(de)intercalation of the lithium ions into anode material22and cathode material26. It is noted that cathode material26can contract in the stacking direction18during charging, but to a lesser extent than anode material22expands, and can expand in the stacking direction18during discharging, but to a lesser extent than anode material22contracts.

Battery pack12, which is a solid-state battery because battery cells16include solid-state electrolyte28, can require anywhere between 0.1-10 MPa of uniform pressure on each battery cell16and often must maintain operating temperatures between 20-120 degrees Celsius. Additionally, battery pack12can expand and contract drastically during use, with volume changes ranging anywhere between 10-280%.

To prevent problems caused by the expansion and contraction and operating outside of the range of acceptable operating temperatures, battery system10includes a pressure vessel30, which includes a gas inlet32and a gas outlet34, and a pressurization system36. The battery pack12is inside of the pressure vessel30, which can be formed of a plastic interior layer30aand a carbon fiber exterior layer30bsurrounding the plastic interior layer30a. Pressure vessel30is provided with an inlet end cap38plugging a first open end39of the pressure vessel and sealingly surrounding the gas inlet32, and an outlet end cap40plugging the second open end41of the pressure vessel30and scalingly surrounding the gas outlet34. End caps38,40can be made of aluminum.

The pressurization system36is configured for conveying heated compressed gas into the pressure vessel30to provide constant pressure to battery cells16during the charging and discharging in order to provide sufficient ionic conductivity between anode material22and cathode material26, and to maintain the operating temperature within the range of acceptable operating temperatures.

Pressurization system36is configured for conveying compressed gas into the pressure vessel30via the gas inlet32to generate a force on the battery housing14for maintaining uniform pressure on each battery cell16in the stacking direction18. The pressurization system36includes a gas inlet line42feeding into the gas inlet32of the pressure vessel30and a gas outlet line44exiting the gas outlet34of the pressure vessel30.

Pressurization system36further includes a controller46configured to control a flow rate of heated compressed gas to pressure vessel30to control the temperature within pressure vessel30and configured to control a pressure within the pressure vessel30to maintain uniform pressure on each battery cell16. More specifically, battery system10includes a control valve48in gas inlet line42and a pressure relief valve50in gas outlet line44. Controller46is configured to control a flow rate of heated compressed gas to pressure vessel30by sending control signals to control valve48and to control the pressure within the pressure vessel30by sending control signals to pressure relief valve50. Pressure relief valve50also maintains the pressure of battery pack12when the vehicle HVAC system202(FIG.2) is shut off. The pressurization system36includes a check valve52in the gas inlet line42for allowing compressed gas to flow into the gas inlet32and preventing backflow from the gas inlet32.

Battery system10further includes a cable54enclosing wires entering into the pressure vessel via the first open end39by passing through the inlet end cap38. Alternatively, cable54can enter into the pressure vessel30via the second open end41by passing through the outlet end cap40. The wires can be high voltage electrical wires or data wires, and cable54connects directly to the battery pack12.

The battery system10can further include a heat exchanger56inside the pressure vessel30and in contact with the battery pack12for cooling the battery cells16. An inlet coolant line58is provided for delivering coolant into the pressure vessel30and into the heat exchanger56via the first open end39by passing through the inlet end cap38. An outlet coolant line60is provided for delivering coolant out of the pressure vessel30and away from heat exchanger56via the second open end41by passing through the outlet end cap40. Alternatively, inlet coolant line58can enter via second open end41and outlet coolant line60can exit via first open end39.

FIG.2includes an onboard system200of a motor vehicle that includes battery system10. Onboard system200further includes an HVAC system202configured for absorbing heat from a cabin of the motor vehicle and producing heated compressed gas that is supplied to pressurization system36. The heated compressed gas can advantageously be carbon dioxide. The HVAC system202includes an evaporator204within the cabin of the motor vehicle configured for absorbing heat from the cabin and evaporating liquid refrigerant into gas. HVAC system202further includes a compressor206configured for compressing and heating the gas, and a condenser208configured for cooling the heated compressed output by the compressor206and condensing the gas into a liquid.

The control valve48is provided directly downstream of compressor206and is configured for directing the heat compressed output by the compressor206to gas inlet line42of pressurization system36and/or to the condenser208. The heated compressed gas can thus be directed to gas inlet line42through the check valve52and into pressure vessel30to heat the battery cells16and pressurize pressure vessel30to maintain sufficient contact between the battery cells16.

The gas exiting pressure vessel30flows in gas outlet line44through pressure relief valve50to merge with the liquid refrigerant output by condenser208. The HVAC system202further includes a dryer210downstream from the pressure relief valve and configured for receiving liquid refrigerant from condenser208, which has merged with the gas in gas outlet line44. An expansion valve212of HVAC system202is downstream of the dryer210for regulating the flow of liquid refrigerant into evaporator204.

Onboard system200further includes a comprising cooling loop214providing coolant to the inlet coolant line58and receiving coolant from the outlet coolant line60. Cooling loop214utilizes components of HVAC system202to provide coolant to heat exchanger56to cool battery cells16of battery pack12. The coolant can advantageously be water. The cooling loop214includes a radiator216and a pump218. The coolant flows from the outlet coolant line60through the radiator216, which removes heat from the coolant exiting pressure vessel30in outlet coolant line60, to the pump218. The pump218is configured for pumping the coolant into the heat exchanger56via the inlet coolant line58.

The cooling loop214also includes a control valve220in outlet coolant line60. Control valve220includes a first outlet for providing coolant output from pressure vessel30to an inlet of radiator216and a second outlet for providing the coolant output from pressure vessel30to a cabin heating system222, which is part of HVAC system202and heats the cabin of the motor vehicle. Upstream of cabin heating system222, cooling loop214includes a heater224for providing heat to the cabin heating system222. Heater224can be a positive temperature coefficient (PTC) heater. Cabin heating system222can include a heater core for removing the heat from the coolant passing therethrough and a blower for blowing the heat into the cabin. Coolant exiting cabin heating system222is thus cooled, and can also be provided to pump218by a coolant line extending from the cabin heating system222to the pump218, and pumped through inlet coolant line58into pressure vessel30to cool battery cells16.

In the preceding specification, the present disclosure has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present disclosure as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.

LIST OF REFERENCE CHARACTERS