LIBAL -BMS LOW VOLTAGE™COMPACT BATTERY MANAGEMENT SYSTEM

Product Presentation

c

System overview

1. cBMS3. BATTRY PACK4. SHUNT/HAL5. CHARGE CONTACTOR6. HV- MAIN CONTACTOR7. HV+ MAIN CONTACTOR8. PRE CHARGE CONTACTOR9. CHARGER (CAN or PWM)10. CAN DISPLAY 11. DIAGNOSTIC TOOL

HV +HV –CELL MONITORINGTEMPERATURE MONITORINGCAN 1CAN 2INPUT SIGNALSOUTPUT SIGNALSKEY SWITCH 80

% SoC

80%

SoC

80%

SoC

80%

SoC

80%

SoC

80%

SoC

80%

SoC

80%

SoC

Resistor

VCU

34

5

9

6

7

8

10

11

6-34V

4

BMS Creator™

B

BatteryCharger

B

Vehicle

cBMS overview

• Single PCB for up to 24 lithium-ion cells in series.

• 6 External temp sensors and 4 on-board

• 4 GPIO and 4 Input

• Compact design: 150 x 70 mm / 67g

• Designed for highest levels of functional safety on cell voltage, temperature and current

• Full industrial and automotive environmental specifications.

c-BMS electronic layout

Architecture

12 cellmonitoring

ASIC

Safety rated microcontroller

Safety rated power supply

CAN bus

4 Input/OutputControl

12 cellmonitoring

ASIC

Real-timeClock

4 InputControl

6 Pack temp

Functions

Safety• Monitoring with open circuit

protection and redundancy of safety critical circuits• Pack Temperature

• Current

• Cell voltage

• Power supply

• Utilization of safety rated automotive standard components ensures highest possible levels of functional safety.

Functions

Reliability• Extended temperature range (-40°C to

+85°C)

• Tested to the most demanding standards in electromagnetic radiation (EMC) and electrostatic discharges (ESD).

• Tested to the most demanding standards in vibration, shock and impact.

Compactness• Size: 150 x 70 x 15 mm

• Weight: 67g

c-BMSinside

Functions

Performance• State-of-the-art algorithms for

estimation of;

• State of Charge (SOC). (Validated, 0.28 % accuracy)

• State of Health (SOH)

• Dynamic charger control algorithms (Control loop feed-back mechanism)

• Current, voltage and temperature measurements are synchronized at 150 mS sampling rate

• Applicable for all lithium ion battery chemistries.

Power consumption and supply• Broad supply power range: 6 – 35V

• < 2,7 W in operation

• <1,9 mW in sleepmode w. wake-up on CAN and ignition

Usability

• BMS Creator™ , PC configuration tool for easy, fast and intuitive set-up. Enables the battery designer to create a UNIQUE BMS based on standard HW and SW platform

• Supports UDS CAN protocol

• On board Real time clock allow timestamp for errors and events for efficient warranty handling and service management

Specifications

Module Specification Value

Cells to be monitored Up to 24 cells, minimum 11V

Cell voltage range 0.0 – 5.0 V

Cell voltage measurement accuracy. ±1,5 mV (-40 to 85 ⁰C )

Cell voltage sampling 150 mS

Temperature sensors Up to 6

Temp. Measurement acc. ±1⁰C (-40 to 85 ⁰C )

Pack temperature sampling rate 150 mS

Communication CAN bus (non-isolated). Isolated between 12V and ground

Dimensions 150 mm x 70 mm x 15 mm

Weight 67 g

Balancing current Up to 200 mA/cell

I/O ports 4

Input ports 4

Specifications

System specifications Value

Pack voltage range Up to 100V

Pack current range Up to 2000 A

Pack current measurementaccuracy

±1%

Pack voltage accuracy ±1,0 VDC

Pack current measurementsampling rate

150 mS

Temperature range -40⁰C to 85⁰C

Stanby consumption (sleep mode)

< 2,5 mW

Active consumption < 2.7 W

Current measurement Shunt or Hall effect sensor

Power Supply 6-35 V

Test/Certification

Tests Standards

EMC CISPR 12, 16, 22, 25IEC EN 61000-4-4ISO 11452/11452-4/2ISO 16750-2ISO 7637-2

Vibration ISO 16750-3

Temperature ISO 16750-4

Humidity ISO 16750-4

APPENDIX

Functional Safety

The c-BMS is designed to have no safety critical undetected singlepoint failures. This is achieved by:

• Cell voltage input open wire detection

• Cell voltage and temperature measurement self test

• Internal and external MUX self test

• Power supply with watchdog protection, self test and CRC.

• Dual-core Lockstep cycle-by-cycle CPU

• CPU build in self test

• ECC on CPU FLASH and RAM

• CPU Clock and Voltage monitoring

• Pre qualified safety rated key components

• Pre qualified RTOS

Safety concept

SG1: Prevent battery fires

SG2: Non-battery fires SG3: Toxic fumes

SG4: Maintain drivability SG5: Electrical shock

The safety concept is defined by five safety goals for the battery management system.

The safety goals are split into functional safety requirements that can be managed by firmware or hardware.

c-BMS ASIL ratings

Measurement / Control Accuracy Sample rate ASIL rating

Cell voltage ± 1.5 [mV] 20 [ms] C (D)

Cell temperature ± 1 [°C] 1000 [ms] C (D)

Pack current (Hall effect and Shunt) ±0.2 % 10 [ms] C (D)

Relay control - - C (D)

Isolation resistance (25-1000 [VDC]) ± 5 % 10 [sec] A

Load/Charger terminal voltage ± 2 [VDC] 100 [ms] QM

Supply voltage ± 2 % 100 [ms] QM

Accuracy numbers valid in the full temperature range of -40 to +85 [°C]

Pack current accuracy is stated as a maximum error on the input signal. Valid shunt input range is ± 255 [mV] and valid Hall effect input range is 0 to 5 [VDC]

Safety implementation

-H

igh

vo

ltag

e b

atte

ry p

ack

+

Load

Cell voltage –ASIL D

PSU – ASIL D

Processor + RTOS – ASIL D

Current – ASIL CCell Temperature

– ASIL C

Contactor control – ASIL C

Current measurement Contactor

Contactor

Cell voltage open wire detection

-B

atte

ry c

ell

+ Cell voltage – ASIL DSW 1

When SW 1 is closed, closing SW 2 only adds a small voltagedrop to the measurement. The wire is not detected as open.

R1

SW 2V

If SW 1 is open, closing SW 2 will cause the voltage measurementto read close to zero. The wire is detected as open.

Temperature mux fault detection

Cell voltage – ASIL D

NTC sensor input switched through the MUX is always checked Against known fixed resistors (R1 and R2) for MUX failure detection.

NTC

Cell Temperature – ASIL C

MUXR1

The ASIL D voltage measurement is also used to convert the NTC signal from the MUX.

R2

PSU and processor failure detection

If SPI communication is lost or the Processor signals an Error condition, the PSU will try to recover the Processor. If unsuccessful,it will enter a safe state and wait for a new ignition signal.

PSU

Processor

Power

SPI communication

Error hardware signal

AuxSwitchable power

Ignition

Reliable Software

Operating System• Certified Real Time

Operational System (pre-certified to ISO 26262 ASIL D by TÜV SÜD)

Development Guidelines• Standardised Software

development guidelines MISRA C (Motor Industry Software Reliability Association).

Test Tools• Standardised dynamic and

static test tool to document compliance with ISO-26262 ASIL C test coverage

Processor failure detection

Processor

CPU self test, Lockstep CPU design, Memory Protection Unit, Error Correcting Code memory for flash / RAM, Memory BIST, Error signalling module, Clock and Voltage monitoring.