HV junction box
Everything the junction box needs to periodically measure, report, and control on one board.
A single controller, running from a 12 V to 24 V supply, that measures voltage across up to six high-voltage sensing channels, measures charge and discharge current across up to two current-sensing channels, monitors shunt resistor temperature across up to three temperature-sensing channels for calibration, continuously measures isolation resistance, and detects thermal events from pressure, gas, humidity and temperature sensors. It drives up to four contactors, reports state to the central controller over the 10BASE-T1S interface, and switches its contactors on the controller’s command.
The hardware is a Safety Element out of Context designed to meet ISO 26262 ASIL D. Pack current, high-voltage measurement, isolation measurement and contactor control each carry their own rating, and the host reaches all of them through a simple, configurable device driver.
These functions are usually spread across three or four separate parts inside the box, each with its own wiring, its own supplier and its own safety argument. Bringing them onto one board shortens the harness and removes connectors, and it leaves a single interface to integrate, validate and qualify. The saving is in engineering effort as much as in bill of materials.
Contactors, enclosure and busbars remain yours to choose. We supply the controller.
| Parameter | Value |
|---|---|
| Battery Module Board (BMB) Interface | Dedicated front end (BMB_IF), daisy-chain to the first of a chain of Battery Module Boards, independent of the main measurement path |
| HV analog inputs up to ASIL D | Up to 6 high-voltage sensing channels, on switched resistor dividers |
| Current sensing ASIL D | Up to 2 channels, charge and discharge current |
| Continuous current | 1000 A |
| Peak current | 4000 A |
| Temperature sensing | Up to 3 channels, shunt resistor temperature for calibration |
| Isolation up to ASIL D | Continuous measurement, derived from the HV measurement network |
| Thermal event detection | Pressure, gas, humidity and temperature sensors |
| Contactor control ASIL D | Up to 4 contactors |
| Host interface | 10BASE-T1S automotive Ethernet |
| Supply | 12 V to 24 V (KL30) |
| Operating temperature | −40 °C to +105 °C, automotive grade |
| Functional safety | SEooC, ASIL D target |
Multiple EBJB1500 nodes share one bus, managed by the central controller.
Each EBJB1500 only measures and reports — brick voltages, pack V and I — and switches its contactors on command; it makes no trip decisions of its own. The controller reads those reports over a single multidrop 10BASE-T1S segment, decides when to open a contactor, and keeps a continuous heartbeat running to every node. If that heartbeat stops, the node opens its contactors as a fail-safe.
