Battery knowledge · Modules, packs and battery management
Current sensor
The device that measures pack current for coulomb counting and protection: a precision shunt resistor read by an amplifier, or a Hall-effect sensor around the cable. Offset error in this sensor is what makes SOC drift between OCV corrections. [1]
- Also called
- shunt, Hall sensor
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 Current sensor alongside Battery disconnect unit in this context. The box inside the pack that holds the contactors, pre-charge circuit, main fuse or pyrofuse and current sensor, where the pack’s high-voltage connections are made and broken.
Use in Lemonergy
Lemonergy Studio blocks
Relate current and voltage
Conserving components solve constitutive relations and node balance.
Blocks to use
- Controlled voltage source
Supplies voltage
Inputs & settings
- voltageV
- Resistor
Relates current and voltage
Inputs & settings
- resistanceOhm
- Electrical reference
Sets zero potential
Inputs & settings
- Connect p to reference net
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
Example. A 1 V drop across 2 Ω implies 0.5 A.
Observe. Topology sets individual element voltages.
The RC example includes a capacitor: transient current varies and source voltage is not always resistor voltage.
Open the electrical circuit →References & further reading
Technical references
- Getting Started with the BQ76925
Texas Instruments · 2019
Technical reference · A concrete BMS analog front-end example: cell voltage, current, temperature measurement and MCU integration.
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.