Battery knowledge · Modules, packs and battery management
Energy management system
The site-level controller of a storage system that decides when to charge and discharge according to prices, grid signals and the battery’s limits, and dispatches those commands to the BMS and inverters.
- Abbreviation
- EMS
Example
Modules, packs and battery management: an example situation
Twelve 3.6 V, 5 Ah cells in 6s2p give 21.6 V, 10 Ah and 216 Wh nominally before other restrictions.
Read Energy management system alongside Battery management system in this context. The electronics and software that keep a battery inside its safe window: measuring every cell voltage and many temperatures, estimating SOC and SOH, balancing cells, computing current limits, controlling the contactors and reporting over the vehicle network.
Use in Lemonergy
Lemonergy Studio blocks
Share a site supply
Multiple branches share one power cap.
Blocks to use
- Shared site power allocator
Shares grid-side power
Inputs & settings
- limitW
- ports
- allocation
- Charging schedule and target policy
Permits charging
Inputs & settings
- strategy
- targetSoc
- departureS
- soc, available, chargerDone → permit
- Regulated CC/CV charger
Regulates current and voltage
Inputs & settings
- currentA
- voltageV
- cutoffCurrentA / cutoffHoldS
- Electrical ports p and n
- Battery with SOC-dependent OCV
Stores charge and supplies terminal voltage
Inputs & settings
- capacityAh
- initialSoc
- emptyVoltageV / fullVoltageV
- resistanceOhm
- Electrical ports p and n
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
- Compare proportional and input-priority allocation.
- Lower the cap at fixed departure times.
Example. Three vehicles requesting 11 kW each under a 22 kW cap initially receive 7.33 kW each with proportional allocation.
Observe. The site cap can hold while a vehicle misses its target.
Downstream unused capacity is not silently redistributed.
Open the Studio example →References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs: Part 2. Modeling and identification
Gregory L. Plett · Journal of Power Sources · 2004
Topic background · Battery charge balance, open-circuit voltage, ohmic loss, polarization dynamics and model identification; parameters require cell-specific data.
- Getting Started with the BQ76925
Texas Instruments · 2019
Topic background · A concrete BMS analog front-end example: cell voltage, current, temperature measurement and MCU integration.