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Linear Technology Introduces New High Voltage Battery Stack Monitor IC for EV/HEV Systems

Linear Technology has introduced the LTC6802, a highly integrated multicell battery monitoring IC capable of measuring up to 12 individual battery cells. The device’s proprietary design allows multiple LTC6802s to be stacked in series without optocouplers or isolators, for precision voltage monitoring of every cell in long strings of series-connected batteries.

Long battery strings enable high power, rechargeable applications, such as electric and hybrid electric vehicles, scooters, motorcycles, golf carts, wheelchairs, boats, forklifts, robotics, portable medical equipment, and uninterruptible power supply (UPS) systems.

Lithium-ion batteries are poised to be the power source of choice for these applications. However, designing a large, highly reliable and long-lasting Li-ion battery stack remains a complex problem. Li-ion cells can be sensitive to overcharging or over-discharging, requiring that each cell in a stack is carefully managed. The LTC6802 makes this possible with quick and accurate measurements of all cell voltages, even in the presence of stack voltages of more than 1,000V.

The maximum total measurement error is guaranteed at less than 0.25% from -40°C to 85°C and all cell voltages in a battery stack can be measured within 13 ms. Each cell is monitored for undervoltage and overvoltage conditions, and an associated MOSFET switch is available to discharge overcharged cells. Each LTC6802 communicates via a 1MHz serial interface, and includes temperature sensor inputs, GPIO lines and a precision voltage reference.

The LTC6802 was designed for the environmental and reliability challenges of automotive and industrial applications. It is fully specified for operation from -40°C to 85°C and offers diagnostics and fault detection. The LTC6802 is a small 8mm x 12mm surface mount device. The combined robustness, exceptional precision and tiny package directly address the critical requirements of emerging and advanced battery technologies.

Comments

Andrew

If I understand it corectly, this should be hot news for EV enthusiasts. Li-ion BMS just got a bit simpler.

The mosfet switch makes it convenient to integrate into a board used for battery balancing as well as DAQ. It also has an addressable serial interface. I assume data could be sent to a CAN bus interface.

I hope these make it into some BMS's for EV'ers. I have an open order for a good BMS system suitable for a modular battery pack. Each module having 10 Thundersky 90Ah. (CANbus capable please)

I'm sure some braniac can use this to build a fully functional modular BMS on a single card.


Andrew

On second thoughts a 45A mosfet might get a bit too pricey..

Anyone got another suggestion for a 2-3 KWh pack module?

ToppaTom

I am sure there are many other valuable advances like this that are coming together to make BEVs the cost effective (as well as the green) choice for a new vehicle.
They can't get here too soon.

Reality Czech

84 A 12 V power MOSFET, 89 cents each quantity 450.

Andrew

That might do it ... thank you Mr Czech

Shouldn't be long before we see some good battery balancing BMS cards with DAQ functionality.

 Frank

Lithium-ion batteries are poised to be the power source of choice for these applications. However, designing a large, highly reliable and long-lasting Li-ion battery stack remains a complex problem. Li-ion cells can be sensitive to overcharging or over-discharging, requiring that each cell in a stack is carefully managed.

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