IP Library Granted Patent US 12,496,895
Granted Patent B2
US 12,496,895 · App. 18/379,783 · Granted Dec 16, 2025

Liquid cooling system for an electric vehicle

Inventor: David Boyd (Fremont, CA)
Assignee: KUBOTA CORPORATION
B60K11/04B60L53/22H01M10/46H01M10/613H01M10/625H01M10/6569H05K7/20263H05K7/20272H05K7/20927B60L2210/10H01M2220/20
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Quick Facts
Patent No.
US 12,496,895
App. No.
18/379,783
Granted
Dec 16, 2025
Kind
B2
Abstract

A liquid cooling system includes a radiator to cool a coolant when the coolant flows through the radiator, a first coolant pump to circulate the coolant, a second coolant pump to circulate the coolant, an inverter to be cooled by the coolant, an electric motor to be cooled by the coolant and connected to the inverter, a heat exchanger through which the coolant and another liquid can circulate, an Onboard Battery Charger with a DC-to-DC converter to be cooled by the coolant, and a secondary DC-to-DC converter to be cooled by the coolant. The first coolant pump and the second coolant pump are each connected to the radiator.

Claims (63)

1 . A liquid cooling system for a vehicle, the liquid cooling system comprising:

a radiator to cool a coolant when the coolant flows through the radiator;

a first coolant pump to circulate the coolant;

a second coolant pump to circulate the coolant;

an inverter to be cooled by the coolant;

an electric motor to be cooled by the coolant and connected to the inverter;

a heat exchanger through which the coolant and another liquid can circulate;

an Onboard Battery Charger with a DC-to-DC converter to be cooled by the coolant; and

a secondary DC-to-DC converter to be cooled by the coolant; wherein

the first coolant pump and the second coolant pump are each connected to the radiator.

2 . The liquid cooling system according to claim 1 , wherein

the first coolant pump, the inverter, and the electric motor are included in a first coolant path circuit;

the second coolant pump, the heat exchanger, the Onboard Battery Charger with the DC-to-DC converter, and the secondary DC-to-DC converter are included in a second coolant path circuit; and

the first coolant path circuit and the second coolant path circuit are parallel coolant path circuits.

3 . The liquid cooling system according to claim 2 , further comprising:

a first coolant path coupling; and

a second coolant path coupling; wherein

the first coolant path coupling is located between the radiator and each of the first coolant pump and the second coolant pump; and

the second coolant path coupling is located between the radiator and an end of the first coolant path circuit and between the radiator and an end of the second coolant path circuit.

4 . The liquid cooling system according to claim 3 , wherein

the first coolant path coupling includes a Y connector; and

the second coolant path coupling includes a T connector.

5 . The liquid cooling system according to claim 2 , wherein

in the first coolant path circuit, the coolant flows from the first coolant pump to the inverter and from the inverter to the electric motor.

6 . The liquid cooling system according to claim 2 , wherein

in the second coolant path circuit, the coolant flows from the second coolant pump to the heat exchanger, from the heat exchanger to the Onboard Battery Charger with the DC-to-DC converter, and from the Onboard Battery Charger with the DC-to-DC converter to the secondary DC-to-DC converter.

7 . The liquid cooling system according to claim 1 , wherein

the other liquid includes a hydraulic fluid; and

the heat exchanger is operable to remove heat from the other liquid when the coolant and the other liquid circulate through the heat exchanger.

8 . The liquid cooling system according to claim 1 , further comprising:

a blower fan to direct air across the radiator.

9 . The liquid cooling system according to claim 1 , wherein

the Onboard Battery Charger with the DC-to-DC converter is operable to charge one or more battery modules included in the vehicle; and

the secondary DC-to-DC converter provides electrical power to one or more accessories of the vehicle.

10 . The liquid cooling system according to claim 9 , wherein

the one or more accessories of the vehicle include blower fans to move chilled air.

11 . The liquid cooling system according to claim 1 , wherein

the radiator is mounted on a roof of the vehicle.

12 . The liquid cooling system according to claim 11 , wherein

the vehicle includes:

a first housing supported by a chassis; and

a first side housing and a second side housing arranged on opposing lateral sides of the first housing;

each of the first housing, the first side housing, and the second side housing house one or more battery modules connected to the electric motor; and

the first coolant pump and the second coolant pump are both mounted on the second side housing.

13 . The liquid cooling system according to claim 12 , wherein

the vehicle includes a cabin frame that is connected to the chassis and supports the roof of the vehicle; and

a fluid connection between the radiator and the first coolant pump and a fluid connection between the radiator and the second coolant pump extend through internal portions of the cabin frame.

14 . The liquid cooling system according to claim 12 , wherein

the first coolant pump and the second coolant pump are located adjacent to one another on a front surface of the second side housing.

15 . The liquid cooling system according to claim 12 , wherein

the inverter is mounted to a bottom of the chassis and under the first housing.

16 . The liquid cooling system according to claim 12 , wherein

the Onboard Battery Charger with the DC-to-DC converter is mounted to a bottom of the chassis and under the first housing.

17 . The liquid cooling system according to claim 1 , further comprising:

a blower fan to direct air across the radiator; wherein

the blower fan and the radiator are both mounted on a roof of the vehicle.

18 . The liquid cooling system according to claim 1 , wherein

the inverter and the electric motor are mounted on the vehicle; and

the inverter is located forward of the electric motor in a front-rear direction of the vehicle.

19 . The liquid cooling system according to claim 1 , wherein

the radiator is located adjacent to a condenser included in an air cooling system to cool one or more battery modules that provide electric power to the electric motor.

20 . The liquid cooling system according to claim 19 , wherein

the radiator and the condenser are both mounted to a roof of the vehicle that includes the electric motor.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 13, 2023
From: BOYD, DAVID
To: KUBOTA CORPORATION
Reel/Frame 065210/0641 →
Continuity (1)
Related Publication 20250121674A1 · Apr 17, 2025
References Cited (13)
US 10634402B2 · Kim · 2020 [cited by examiner]
US 20180086224A1 · King · 2018 [cited by examiner]
US 20190039434A1 · Wallace · 2019 [cited by examiner]
US 20200290426A1 · Aikawa et al. · 2020 [cited by applicant]
US 20210268892A1 · Kawabe · 2021 [cited by applicant]
US 20220163132A1 · Jeong · 2022 [cited by examiner]
US 20220355648A1 · Kim · 2022 [cited by examiner]
US 20250101902A1 · Lee · 2025 [cited by examiner]
US 20250121656A1 · Boyd · 2025 [cited by examiner]
US 20250121675A1 · Wright · 2025 [cited by examiner]
Official Communication issued in corresponding European Patent Application No. 24203399.1, mailed on Mar. 24, 2025, 10 pages. [cited by applicant]
Boyd, “Liquid Cooling System for an Electric Vehicle”, U.S. Appl. No. 18/379,785, filed Oct. 13, 2023. [cited by applicant]
Wright, “Liquid Cooling System for an Electric Vehicle”, U.S. Appl. No. 18/379,788, filed Oct. 13, 2023. [cited by applicant]