GB/T 32895-2025 Communication protocols for swapping battery pack of electric vehicle
1 Scope
This document specifies the requirements for the communication physical layer, data link layer, application layer, overall communication process, CAN message and compatibility for the swapping battery pack of electric vehicle (hereinafter referred to as the "battery pack") based on the controller area network (CAN2.0/CAN FD).
This document is applicable to the communication between the battery pack and the charging system of the battery swap station (hereinafter referred to as the "battery swap station").
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 19596 Terminology of electric vehicles
GB/T 27930 Digital communication protocols between off-board conductive charger and electric vehicle
GB/T 29317 Terminology of electric vehicle charging/battery swap infrastructure
ISO 11898-1 Road vehicles - Control area network (CAN) - Part 1: Data link layer and physical coding sublayer
ISO 11898-2 Road vehicle - Control area network (CAN) - Part 2: High-speed physical medium attachment (PMA) sublayer
ISO 11898-5 Road vehicles - Controller area network (CAN) - Part 5: High-speed medium access unit with low-power mode
SAE J1939-11 Recommended practice for serial control and communication vehicle network - Part 11: Physical layer - 250 kbits/s, twisted shielded pair
SAE J1939-73:2006 Recommended practice for serial control and communication vehicle network - Part 73: Application Layer - Diagnostics
SAE J1939-81:2006 Recommended practice for serial control and communication vehicle network - Part 81: Network Management
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 19596 and GB/T 29317 and the following apply.
3.1
frame
set of ordered data bits constituting a complete message
Note: The frame is divided into several fields, each of which includes predefined types of data.
3.2
CAN data frame
ordered bit fields necessary for the CAN protocol for data transport, starting with the start of frame (SOF) and ending with the end of frame (EOF)
3.3
messages
one or more CAN data frames having the same parameter group number
3.4
identifier
identity part of the CAN arbitration field
3.5
extended frame
CAN data frame that adopts a 29-bit identifier, as defined in the CAN 2.0B specifications
3.6
standard frame
CAN data frame that adopts an 11-bit identifier, as defined in the CAN 2.0B specifications
3.7
priority
3-bit field in the identifier that sets the arbitration priority during transport
Note: Grade 0 is the highest priority and Grade 7 is the lowest priority.
3.8
parameter group; PG
set of parameters transmitted in a message
Note: PGs include command, data, request, response and negative response.
3.9
parameter group number; PGN
24-bit value that uniquely identifies a parameter group
Note: The PGN is composed of reserved bit, data page, PDU format field (8-bit), and PDU specific field (8-bit).
3.10
suspect parameter number; SPN
19-bit value assigned to each parameter by the application layer through the parameter description signal
3.11
protocol data unit; PDU
specific format of the CAN data frame
3.12
transport protocol
part of the data link layer, a mechanism for transporting PGNs with data lengths ranging from 9 bytes to 1,785 bytes
3.13
battery management system; BMS
system capable of monitoring the state (e.g. temperature, voltage and state of charge) of battery and providing communication, safety, cell equalization and management control for battery as well as providing the communication interface with application equipment
4 General provisions
4.1 The communication interface of the battery pack adopts CAN bus (including CAN2.0 and CAN FD), which is compatible with the communication network of the road vehicle control system, where:
a) CAN communication interface between charging equipment and BMS (hereinafter referred to as "charging CAN"), whose communication network is based on CAN2.0B using extended frames;
b) CAN communication interface between vehicle management system and BMS (hereinafter referred to as "monitoring CAN"), whose communication network is based on CAN bus (including CAN2.0 and CAN FD), using standard frames or extended frames.
4.2 When the charging CAN is used for communication interaction between the battery pack and the power changer station, the message shall meet the requirements of 9.1. When the monitoring CAN is used for communication interaction between the battery pack and the power changer station, the message shall meet the requirements of 9.2.
4.3 The format and content of charging CAN and monitoring CAN messages should meet the relevant requirements specified in Annex A and Annex B.
4.4 After the battery pack is physically connected and the BMS auxiliary power is powered on and woken up in the battery swap station, there shall be two states: static monitoring state and charge/discharge state. See Figure 1 for the state transition of battery pack in the battery swap station.
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 General provisions
5 Physical layer
6 Data link layer
7 Application layer
8 Overall communication flow
9 CAN message
10 Requirements for compatibility
Annex A (Informative) Charging CAN message
Annex B (Informative) Monitoring CAN message
Annex C (Informative) Network topology of battery pack
Annex D (Informative) Battery pack address configuration
Annex E (Informative) Process requirements for battery pack in battery swap station
Annex F (Informative) Start and end conditions of charging CAN message
Bibliography
