# US 2021/0242511 A1 · Ocv estimation of vehicle battery in non-equilibrium state > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242511 A1 - Document ID: US20210242511A1 - Status: Published application - Kind: A1 - Application number: 16/776,905 - Filed: 2020-01-30 - Published: 2021-08-05 - Earliest claimed: 2020-01-30 - Applicants: Bordrin New Energy Vehicle Corporation, Inc. - Inventors: FOAD SAMADI; YONGHUA LI - Web page: https://patentgrep.com/patent/US20210242511A1 ## CPC - H01M 10/482: {for several batteries or cells simultaneously or sequentially} - G01R 31/3648: {comprising digital calculation means, e.g. for performing an algorithm} - G01R 31/388: involving voltage measurements - H01M 10/425: {Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00)} - H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - H01M 10/486: {for measuring temperature} - H01M 50/20: Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders (structural combination of accumulators with charging apparatus H01M10/46) - H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane - Y02E 60/10: Energy storage using batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A system and method for battery management of a vehicle is provided. The battery management system may include a battery cell or pack; a contactor and a battery controller. The contactor may be connected to the battery cell or pack. The battery controller may be connected to the battery cell or pack and the contactor. The battery controller may acquire a first measurement of the battery in response to a Keyoff event after disconnection of the contactor. The battery controller may also acquire a second measurement of the battery in response to a Keyon event before connection of the contactor. The battery controller may determine an open circuit voltage (OCV) of the battery cell or pack based on the first and second measurements. For example, the acquired OCV may be used to estimate SOC of the battery and may be used to calibrate the SOC estimation algorithm or other algorithms. The battery controller may also use the acquired measurements to identify the battery model parameters. ## Claims ### Claim 1 A battery management system for a vehicle comprising: a battery cell or pack; a contactor connected to the battery cell or pack; a battery controller connected to the battery cell or pack and the contactor, the battery controller being configured to acquire at least one first measurement of the battery in response to a Keyoff event after disconnection of the contactor; the battery controller being further configured to acquire at least one second measurement of the battery in response to a Keyon event before connection of the contactor, the battery controller being configured to determine an open circuit voltage (OCV) of the battery cell or pack based on the at least one first measurement and the at least one second measurement. ### Claim 2 (depends on 1) The battery management system of claim 1, wherein the OCV is determined based on a curve fitting of the at least one first measurement and the at least one second measurement. ### Claim 3 (depends on 1) The battery management system of claim 1, wherein the battery controller is configured to acquire at least one first measurement of the battery cell or pack in response to a Keyoff event after disconnection of the contactor. ### Claim 4 (depends on 2) The battery management system of claim 2, wherein the battery controller is configured to acquire at least one second measurement of the battery in response to a Keyon event before connection of the contactor. ### Claim 5 (depends on 2) The battery management system of claim 2, wherein the battery controller is configured to determine whether the battery offline time between an end of the at least one first measurement to an end of the at least one second measurement is sufficient to predict the OCV profile of the battery cell or pack. ### Claim 6 (depends on 5) The battery management system of claim 5, wherein the battery controller is configured to determine whether a number of collected data points are sufficient to perform a fitting of obtained voltage terminal profile while contactor was off. ### Claim 7 (depends on 4) The battery management system of claim 4, wherein the battery controller is configured to determine if the temperature difference between collection of first and second measurements is in the range that allows for OCV estimation. ### Claim 8 (depends on 4) The battery management system of claim 4, wherein the battery controller is configured to perform a curve fitting algorithm of the at least one first measurement and the at least one second measurement. ### Claim 9 (depends on 1) The battery management system of claim 1, wherein the battery controller is configured to determine the terminal voltage if contactor remains off for a time period using the fitting equation achieved. ### Claim 10 (depends on 1) The battery management system of claim 1, wherein the battery controller is configured to estimate SOC based on acquired OCV. ### Claim 11 (depends on 3) The battery management system of claim 3, wherein the battery controller is configured to utilize SOC as the initial SOC to calibrate SOC estimation algorithm and other model-based battery state estimation algorithms. ### Claim 12 A method of OCV prediction of a battery cell or pack based on data collection before power down and after power up. ### Claim 13 (depends on 12) The method according to claim 12, further comprising acquiring at least one first measurement of the battery cell or pack in response to a Keyoff event after disconnection of a contactor. ### Claim 14 (depends on 13) The method according to claim 13, further comprising acquiring at least one second measurement of the battery in response to a Keyon event before connection of the contactor. ### Claim 15 (depends on 14) The method according to claim 14, further comprising determining whether battery offline time since the end of first set of measurement to end of second measurement is sufficient to predict the OCV profile of the battery cell or pack. ### Claim 16 (depends on 15) The method according to claim 15, further comprising determining whether the number of collected data points are sufficient to perform a fitting of obtained voltage terminal profile while the contactor was off. ### Claim 17 (depends on 16) The method according to claim 16, further comprising determining whether the temperature difference between collection of first and second measurements is in a range that allows for OCV estimation. ### Claim 18 (depends on 17) The method according to claim 17, further comprising performing a curve fitting algorithm of the at least one first measurement and the at least one second measurement. ### Claim 19 (depends on 18) The method according to claim 18, further comprising determining a terminal voltage if a contactor remains off fora time period using the curve fitting equation. ### Claim 20 (depends on 18) The method according to claim 18, further comprising determining whether the battery rest time is longer than sufficient to use existing method to determine OCV.