IEEE 1625 - Battery Design

Standard for Rechargeable Batteries for Multi-Cell Mobile Computing Devices

IEEE 1625 is a standard published by the Institute of Electrical and Electronics Engineers (IEEE) that covers lithium-ion and lithium-polymer rechargeable batteries used in multi-cell mobile computing devices such as laptop computers, portable workstations, and similar devices. It defines requirements for battery manufacturers, charger and system manufacturers, and end-users with the purpose of maintaining safety, promoting reliability, and ensuring interoperability throughout the product lifecycle. The standard was withdrawn (inactivated) by IEEE in 2019 as part of a portfolio review, but remains widely referenced by OEMs, ODMs, and procurement bodies as a de facto quality and safety framework for multi-cell laptop batteries. It should be considered alongside IEC 62133-2 for safety certification purposes.

Published by: Institute of Electrical and Electronics Engineers (IEEE)

Current edition: IEEE 1625-2008 (last edition, July 2008)

Status: Inactivated/withdrawn by IEEE in 2019 — no longer maintained; no direct replacement designated

Companion standard: IEEE 1725-2011 — Rechargeable batteries for cellular telephones (single-cell; IEEE 1625 is the multi-cell equivalent)

Scope

IEEE 1625 applies to rechargeable lithium-ion and lithium-polymer battery packs used in multi-cell mobile computing devices, specifically:

Laptop computers and portable workstations: the primary target application; typically 2S-to-6S battery configurations
Tablet computers and portable displays: multi-cell configurations in larger form factor tablets
Similar mobile computing devices: any portable computing device with a multi-cell Li-ion battery pack

Exclusions: Single-cell batteries (covered by IEEE 1725), stationary energy storage, traction batteries for road vehicles, and consumer electronics beyond mobile computing are not within the stated scope.

Key Requirements

Battery Cell Requirements

Cell certification: cells within the pack must be certified to IEC 62133 (or equivalent) — IEEE 1625 is a system-level standard that requires underlying cell-level safety certification
Cell characterisation: manufacturer must provide comprehensive cell data including capacity, internal impedance, voltage-temperature-current characterisation, and cycle life data
Cell matching: cells within a multi-cell pack must be matched by capacity and internal resistance to reduce imbalance during cycling

Battery Pack Requirements

Protection circuit module (PCM): pack must include a PCM providing overcharge protection, overdischarge protection, overcurrent protection, and short circuit protection for each individual cell
Overvoltage protection: PCM must disconnect charge current if any cell exceeds maximum charge voltage (e.g., 4.20 V or 4.35 V depending on chemistry) within 200 ms
Thermal protection: thermistor or equivalent sensor required; charge and discharge must be inhibited outside defined temperature window (typically 0–45 °C for charge, −20–60 °C for discharge)
Cell balancing: pack must include cell balancing circuitry (passive or active) to maintain cell voltage uniformity throughout pack life
Verification testing: overcharge, overdischarge, short circuit, crush, free fall, and thermal abuse tests must all be passed

Charger and System Interface Requirements

Communication protocol: the battery and host system must implement SMBus (Smart Battery Data Specification) or equivalent communication for state-of-charge reporting, authentication, and charge control
Authentication: IEEE 1625 recommends (but does not mandate) cryptographic authentication between battery and host system to prevent use of uncertified or counterfeit batteries
Charge algorithm: the host system charger must implement constant-current/constant-voltage (CC/CV) charging per the battery manufacturer’s specification
Charger safety requirements: defined requirements for charger protection circuits to prevent overcharge in the event of PCM failure

Manufacturer and End-User Obligations

Cell manufacturer: must test and characterise cells per the standard; make cell data available to battery pack manufacturers; ensure cells pass safety tests
Battery pack manufacturer: must design the pack to meet the standard; test packs; provide documentation and safety data to system manufacturers
System manufacturer: must implement compliant charger and SMBus interface; validate the complete battery-charger-system interaction
End-user guidance: standard includes informative guidance on safe handling, storage, and disposal of multi-cell laptop batteries

Industry Status After Inactivation

Despite being inactivated by IEEE in 2019, IEEE 1625 continues to be cited in:

OEM procurement specifications: major laptop and computing OEMs (HP, Dell, Lenovo, Apple) continue to reference IEEE 1625 in supplier quality requirements
Government and defence procurement: US government purchasing regulations and MIL specifications for computing equipment continue to cite IEEE 1625 as a quality baseline
EPEAT/TCO ecolabels: environmental and safety criteria programmes for computers continue to reference IEEE 1625 compliance as a safety criterion

For regulatory safety certification, IEC 62133-2 is now the preferred standard; IEEE 1625 provides additional quality, lifecycle, and system-integration requirements beyond the minimum safety baseline.

Related Standards

IEC 62133-2 — Safety requirements for portable sealed secondary lithium cells and batteries; the preferred safety certification standard for cells in IEEE 1625-compliant packs
IEEE 1725 — Standard for rechargeable batteries for cellular telephones; single-cell equivalent; same IEEE series as 1625
IEC 62619 — Industrial Li battery safety; separate scope from IEEE 1625’s computing device focus
IEC 61960-3 — Performance standard for secondary Li cells; provides the cell-performance characterisation data required by IEEE 1625 cell matching requirements
IEEE 1725-2011 — Standard for rechargeable batteries for cellular telephones (single-cell mobile device equivalent)
IEC 62133-2:2017 — Safety requirements for portable sealed secondary lithium cells and batteries (IEC 62133 Part 2, lithium; most relevant modern safety standard for cells used in IEEE 1625-scope packs)

Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.