US 12,334,289 B2
Relay control device and method of controlling relay control device
Hikaru Miura, Hitachinaka (JP); Tatsumi Yamauchi, Hitachinaka (JP); and Mutsumi Kikuchi, Hitachinaka (JP)
Assigned to Hitachi Astemo, Ltd., Hitachinaka (JP)
Appl. No. 18/009,432
Filed by Hitachi Astemo, Ltd., Hitachinaka (JP)
PCT Filed Feb. 5, 2021, PCT No. PCT/JP2021/004265
§ 371(c)(1), (2) Date Dec. 9, 2022,
PCT Pub. No. WO2021/250935, PCT Pub. Date Dec. 16, 2021.
Claims priority of application No. 2020-102587 (JP), filed on Jun. 12, 2020.
Prior Publication US 2023/0230788 A1, Jul. 20, 2023
Int. Cl. G01R 31/327 (2006.01); H01H 47/00 (2006.01)
CPC H01H 47/002 (2013.01) [G01R 31/3278 (2013.01); H01H 2047/003 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A relay control device that controls a relay connected between a secondary battery and a load device, the relay control device configured to
calculate, in a failure diagnosis during energization immediately after the relay is closed, a contact resistance value of the relay based on a voltage applied to the relay and a current flowing through the secondary battery,
set the relay to an energization permitted state when a determination is made that the contact resistance value of the relay is smaller than an initial threshold,
determine, during energization when the energization permitted state is set, a first threshold set as a variable value in accordance with a temperature change amount of the relay by adding an increase in resistance based on the temperature change amount of the relay to the initial threshold, and
compare the calculated contact resistance value with the first threshold to diagnose a failure of the relay.