# US 12,191,702 B2 · Methods for power storage in a power network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,702 B2 - Document ID: US12191702B2 - Status: Granted - Kind: B2 - Application number: 18/307,355 - Filed: 2023-04-26 - Published: 2024-03-21 - Granted: 2025-01-07 - Earliest claimed: 2016-09-15 - Assignees: Form Energy, Inc. - Applicants: Form Energy, Inc. - Inventors: Ramkumar Krishnan; Shawn Fink - Web page: https://patentgrep.com/patent/US12191702B2 ## CPC - H02J 7/34: Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence) - H02J 7/35: with light sensitive cells - H02J 7/50: acting upon multiple batteries simultaneously or sequentially - H02J 7/585: {Sequential battery discharge in systems with a plurality of batteries} - H02J 7/82: Control of state of charge [SOC] - H02J 7/855: {with circuits adapted for supplying loads from the battery} - H02J 7/92: with prioritisation of loads or sources - H02J 7/933: {the cycle being controlled or terminated in response to electric parameters} - H02J 9/061: {for DC powered loads} - H02J 2101/24: Photovoltaics - H02J 2101/28: Wind energy - H02J 2105/12: supplying households or buildings - Y02B 10/70: Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - Y02P 90/50: Energy storage in industry with an added climate change mitigation effect - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A stationary hybrid battery back-up system incorporates two different battery units that differ in terms of recharging efficiency, cycle life, power capability, depth of discharge threshold, temperature threshold, internal impedance threshold, charger rate efficiency and/or stand-by efficiency. The battery back-up system of the present invention comprises an auxiliary power supply that can be used to charge the first and second batteries and/or provide power to a load. When the operating voltage of the system drops, due to a power failure of a power source, the control system may couple the first and/or second battery unit to a load. The control system may have voltage threshold limits wherein it engages the first and second battery units to support the load demand. The first and second battery units may be charge by the auxiliary power supply when the operating voltage is above a threshold level. ## Claims ### Claim 1 A method for power storage in a power network, the method comprising: receiving an operating voltage of power delivered to a load from a power source of a battery system including a first battery unit and a second battery unit; switching between charging and discharging the battery system based on the operating voltage being in a charging range or in a discharging range; and based on comparison of the operating voltage within the charging range to a first charging threshold and a second charging threshold less than the first charging threshold, selecting between different charging modes of charging the first battery unit and the second battery unit, the first battery unit and the second battery unit having different battery chemistries. ### Claim 2 (depends on 1) The method of claim 1, wherein the first battery unit has a higher power efficiency than the second battery unit, and the second battery unit has a higher energy efficiency than the first battery unit. ### Claim 3 (depends on 1) The method of claim 1, wherein the first battery unit includes lithium-ion batteries, and the second battery unit includes metal-air batteries. ### Claim 4 (depends on 3) The method of claim 3, wherein the metal-air batteries include zinc-air batteries. ### Claim 5 (depends on 1) The method of claim 1, wherein the different charging modes include, when the operating voltage is above the first charging threshold, charging the first battery unit and the second battery unit simultaneously each at a predetermined charge rate. ### Claim 6 (depends on 5) The method of claim 5, wherein the different charging modes include, when the operating voltage is below the first charge threshold and above the second charge threshold, charging the first battery unit at a predetermined charge rate and the second battery unit at a decreased rate relative to the predetermined charge rate. ### Claim 7 (depends on 5) The method of claim 5, wherein the different charging modes include, when the operating voltage is below the second charge threshold, charging only the first battery unit at a decreased rate relative to the predetermined charge rate. ### Claim 8 (depends on 1) The method of claim 1, further comprising, based on comparison of the operating voltage within the discharging range to a first discharging threshold and a second discharging threshold less than the first discharging threshold, selecting between different discharging modes of discharging the first battery unit and the second battery unit. ### Claim 9 (depends on 8) The method of claim 8, wherein the different discharging modes include, when the operating voltage is below the second discharging threshold, discharging the first battery unit and the second battery unit simultaneously at a predetermined discharge rate. ### Claim 10 (depends on 8) The method of claim 8, wherein the different discharging modes include, when the operating voltage is above the second discharge threshold and less than the first discharge threshold, discharging the first battery unit at a predetermined discharge rate and discharging the second battery unit at a decreased discharge rate relative to the predetermined discharge rate. ### Claim 11 (depends on 10) The method of claim 10, wherein the different discharging modes includes, when the operating voltage is above the first discharge threshold, discharging only the first battery unit. ### Claim 12 (depends on 1) The method of claim 1, further comprising monitoring a threshold event of the first battery unit and electrically de-coupling the first battery unit from the load based on the threshold event of the first battery unit. ### Claim 13 (depends on 12) The method of claim 12, wherein the threshold event of the first battery unit is a threshold temperature of the first battery unit. ### Claim 14 (depends on 12) The method of claim 12, wherein the threshold event of the first battery unit is a threshold environmental temperature associated with the first battery unit. ### Claim 15 (depends on 12) The method of claim 12, wherein the threshold event is a power capability threshold of the first battery unit. ### Claim 16 (depends on 15) The method of claim 15, wherein the power capability threshold is greater than about 90% of a power capability of the first battery unit. ### Claim 17 (depends on 12) The method of claim 12, wherein the threshold event of the first battery unit is a state of charge of the first battery unit, and the first battery unit is electrically de-coupled from the load when the state of charge of the first battery unit is below a threshold depth of discharge level. ### Claim 18 (depends on 17) The method of claim 17, wherein monitoring the threshold event of the first battery unit includes monitoring impedance of the first battery unit. ### Claim 19 A computer program product encoded on one or more non-transitory computer storage media, the computer program product comprising instructions that, when executed by one or more computing devices, cause the one or more computing devices to perform operations comprising: receiving an operating voltage of power delivered to a load from a power source of a battery system; switching between charging and discharging the battery system based on the operating voltage being in a charging range or in a discharging range; and based on comparison of the operating voltage within the charging range to a first charging threshold and a second charging threshold, selecting between different charging modes of charging a plurality of battery units of the battery system, the plurality of battery units having different battery chemistries. ### Claim 20 (depends on 19) The computer program product of claim 19, further comprising, based on comparison of the operating voltage within the discharging range to a first discharging threshold and a second discharging threshold, selecting between different discharging modes of discharging the plurality of battery units.