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Prius PHEV TechInfo

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Revision as of 18:59, 5 August 2006 by DavideAndrea (talk | contribs) (→‎Battery voltage: added Toyota spec'd range)
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Technical information on the PRIUS useful when designing a conversion.

Original generation

This is the original 4-door sedan:

  • 1997 Japan only release, chassis NHW10 (Gen 1)
  • 2000 worldwide release, chassis NHW11 (Sometimes also called Gen 1, sometimes Gen 2)

Present generation

This is the 5-door hatchback, sometimes called Gen 2, sometimes called Gen 3:

  • 2003 worldwide release, chassis NHW20.


Traction battery

Functions

The traction battery includes a Battery ECU (Electronic Control Unit). This unit does the following:

  • It calculates the battery's S.O.C. by integrating the current ("Coulomb counting") and resetting it to 100 % when the battery voltage surpasses a certain level
  • It reads the pack temperature using 3 thermistors, and the air intake temperature with a 4th thermistor
  • It controls its cooling fan (variable speed)
  • It calculates the battery dynamic resistance (delta voltage over delta current). This resistance increases with battery aging
  • It protects the battery by limiting its current (even down to 0), if the SOC or temperature are at their limits, or the dynamic resistance is too high, or if it detects a fault
  • Broadcasts to the rest of the vehicle, through the CAN bus, the following data:
    • Voltage
    • Current (charging or discharging)
    • Two temperatures
    • Maximum current it's able to provide (discharger)
    • Maximum current it's able to accept (charge)
    • State Of Charge
    • Any fault codes (DTCs)

Battery voltage

Voltage vs State Of Charge at various temperatures
Voltage vs State Of Charge at various discharge currents

If you replace the stock battery, you need to know its voltage, because that's what the vehicle expects. If you add a pack to the stock battery, you need to know its voltage, in order to connect the two together, somehow.

The nominal pack voltage is: 168 cells x 1.2 V = 201.6 V

The pack voltage depends on SOC, temperature and current.

  • The voltage depends on State of Charge and on temperature. It is affected by cold, but not much by heat; so, for temperatures abiove 20 C, use the 20 C curve.
  • The voltage depends on State of Charge and on discharge current. The voltage is not affected by low currents; so, for current below 1.3 A, use the 1.3 A curve.
  • The maximum charge voltage is 1.8 V / cell.
Therefore, roughly, the estimate pack voltage range is:
Max brake No current Max drive
>=20 C, 0% DOD 302 V 237 V 168 V
-10 C, 80 % DOD 302 V 160 V 126 V
So, the estimated overall voltage range is:
Min Nom Max
126 V 202 V 302 V

Though, Hybrid Interfaces reports a range of 165 to 270V, while Toyota specifies a normal range of 150 to 300 V (in READY mode) (Ref: "\Repair Manual\04priusf\05\21bpm\cidlitac.pdf").

See also Toyota Prius Battery Specs

Reconnecting traction battery

  • When working on the HV, remove the orange Service Plug on left end of the battery pack
  • After plugging the orange Service Plug back in:
    • Make sure to slide the Service Plug's handle all the way down. If you don't do this, you can't put the car in "Ready"
    • Disconnect the negative of the 12 V battery for 10 s, reconnect. If you don't do this step, the /!\ symbol will appear on the dashboard, and the car with an explamation point will appear in the Multi-Function Display:
    • Calibrate the "Auto" function of the driver's window. If you don't do this, you can't open or close the window all the way with the Auto switch.
      • Open window half-way
      • Pull and hold window switch up until window is all the way up, and hold an additional 1 second or more

Cabling to traction battery

Harness to the battery

The harness to the traction battery has 3 tails, each with a connector

  • To Battery ECU - power, communication, fan control
  • To the orange Service Plug - to detect if the Service Plug is fully plugged-in
  • To the System Relays - to drive the relays that connect the traction battery to the inverter


Pin-out of connector on Battery ECU

Battery ECU (electronic Control Unit)
Pinout:

  • POWER
    • Gnd - to chassis
    • AM - 12 V, always on, for memory retention
    • IGCT - 12 V when the car is in the "READY" mode
    • IG - 12 V when ignition is on
  • COMMUNICATIONS
    • CANH - CAN bus High
    • CANL - CAN bus Low
  • BLOWER
    • VM - monitors fan voltage, 2 to 12 V
    • SI - variable duty cycle (PWM) square wave to control fan speed
    • FCTL1 - drives the relay which in turn powers the fan

Service Plug sensor.
Two pins. Shorted when the Service Plug is fully plugged-in

System Relays
Four pins:

  • Common
  • System relay 1 (precharge resistor)
  • System relay 2 (traction pack +, bypassing precharge resistor)
  • System relay 3 (traction pack -)


CAN bus

If the conversion will replace the stock Battery ECU, it must talk directly with the vehicle CAN bus.

CAN Tools

  • CAN-View - uses the vehicle's MFD (Multi Function Display). Presently not compatible with the 2006 Prius
  • A generic adapter between the CAN-bus and a PC. It is convenient to use a USB port, though the serial or parallel or Ethernet port may be used as well. Examples of USB adapters:
  • These adapters have a DE-9 DSUB connector, so you'll also need an adapter to the Prius' OBD connector. For example:
  • The Prius' OBD (On Board Diagnostics) connector is located under the dashboard, below and to the right of the steering wheel, facing down. A.k.a.: Data Link Connector 3 (DLC3)
  • Alternatively, tap into the CAN bus directly. Use a short cable to the CAN adapter.
    • CANH - black wire
    • CANL - white wire
    • GND - chassis

CAN bus protocol

  • The CAN bus is active only when the vehicle is in READY mode, and for a few seconds after the end of the READY mode.
  • baud rate: 500 kbits/s (if you use the wrong rate, the vehicle will complain and store a DTC fault until the DTC codes are cleared)
  • Standard: CAN 2.0A ("standard CAN", 11-bit identifier)
  • Remote frames: not used
    • this means all the data are volunteered and none are requested; that is, that every component on the vehicle broadcasts its data periodically; no component puts out requests for data

Battery ECU messages

The Battery ECU (Electronic Control Unit) broadcasts messages to the rest of the vehicle through the CAN bus.

It appears that broadcasting those messages is all the Battery ECU is expected to do. It appears that this ECU only needs to talk, and doesn't need to listen. That is, it doesn't appear that it is expected to do anything about any messages that are placed on the bus by other devices.

The battery ECU is able to protect itself by stating the maximum current it may accept or may provide. It may also protect itself by generating a Fault Code (DTC). In either case, the battery module is at the mercy of the rest of the vehicle to respect those requests and not draw or source too much current.

(Thanks to Attila Vass for pointing to the right codes). The following data were seen in a 2006 Prius.

The Battery ECU (Electronic Control Unit) broadcasts the following messages. In this table, numbers in parentesis (#) refer to the notes just below the table.


ID (hex) Period
[ms] (1)
No of
data
bytes
byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7
03Bh 8 5 Current (2) Voltage (3) CRC (4)


3CBh 100 7 CDL (5) CCL (6) ΔSOC? (11) SOC (7) temp1 (8) temp2 (9) CRC (4)
3CDh 100 5 fault code (10) Voltage (3) CRC (4)


Notes:

  • h = hex value; d = decimal value; b = binary value;
  • A.V.: Attila Vaas (Attila Vass) believes...; D'de: Davide (Hybrids-Plus) believes...


1) How often this message is repeated
2) Pack current: 12-bit, signed (>0 = discharge, <0 = charge) [0.1 A]. Examples:

  • 0F80h = -128d = charging at 12.8 Amps
  • 0000h = 0d= no pack current
  • 0080h = 128d = discharging at 12.8 Amps

3) Pack voltage: 16-bit, unsigned [V]. Note that 2 different messages have this data. Examples:

  • 00DCh = 220d = 220 Volts
  • 0100h = 256d = 256 Volts

4) CRC (Cyclic Redundancy Code): checksum calculated from the data in all the previous bytes; used to check for errors in the data. Lowest 6 bits are simply the sum of the low 6 bits in all the bytes of the message. Unknown algorithm for top 2 bits.
5) Maximum discharging current that the pack can handle: 8-bit unsigned, [A]. A.k.a.: CDL (Current Discharge Limit). From that and the pack voltage, the maximum dicharging power (WOUT) is calculated and reported in the Diagnostics Tool (Typically <= 21 kW).

  • 69h = 105d = 105 Amps -> 21 kW @ 200 V

6) Maximum charging current that the pack can handle: 8-bit unsigned, [A]. A.k.a.: CCL (Current Charge Limit). From that and the pack voltage, the maximum charging power (WIN) is calculated and reported in the Diagnostics Tool (Typically <= 25 kW). Example:

  • 7Ah = 122d = 122 Amps -> 24.4 kW @ 200 V

7) State of Charge: 8-bit, unsigned [0.5%]. Examples:

  • 4Fh = 79d = 39.5 % full (stopped, this is when the motor turns on to start charging the pack)
  • 64h = 100d = 50 % full (stopped, this is when the motor turns off after charging the pack)
  • B4h = 180d = 90 % full

8) A.V.: Lowest temperature reading of any sensor.
D'de: Temperature of the air intake. 8-bit signed, [˚C]. Example:

  • 18h = 26d = 26 ˚C

9) A.V.: Highest temperature reading of any sensor.
D'de: Average temperature of the 3 sensors inside the battery. 8-bit signed, [˚C] Example:

  • FEh = -2d = -2 ˚C

10) Fault Code (DTC = Diagnostic Trouble Code): 16-bit. The 2 Most Significant bits are the type of code (see below). The other 14 bits are the code. See table below for Fault codes. Examples:

  • 0560h = 0000 0101 0110 0000b = DTC P0560 = No voltage at the "AM" contact
  • 3056h = 0011 0000 0101 0110b = DTC P3056 = Problem with the battery current sensor
  • C100h = 1100 0001 0000 0000b = DTC U0100 = No Communication with the Engine Control Module

11) Delta in State of Charge: 8-bit, unsigned [0.5%]. Difference between SOC of most charged block and SOC of least charged block. This is just a guess. Examples:

  • 00h = 0d = 0 % = all block are equally charged
  • 0Ah = 10d = 5 % = the most charged bloc's SOC is 5 % higher than the least charged block


It appears that the battery pack also sends the following data, though it's unclear in which messages:

VMF FAN VOLTAGE Battery blower motor voltage
Min.: 0 V, Max.: 25.4 V
Actuation condition of battery blower motor
COOLING FAN SPD Battery blower motor drive mode
Min.: 0, Max.: 6
Stopped: 0
Low to high speed actuation: 1 to 6
ECU CTRL MODE ECU control mode
Min.: 0, Max.: 4
Operating condition of HV battery
SBLW RQST Battery blower motor stop control request
(standby blower)
Presence of stop control request to battery
V1 to V14 BATT BLOCK Battery block voltage
Min.: –327.68 V, Max.: 327.67 V
Voltage variance among battery blocks

Fault codes

The Battery ECU detects and reports many fault conditions.

  • The Battery ECU places a Fault Code (DTC) in its message with an ID of 3CDh
  • The Engine ECU receives such DTCs (from the Battery ECU and from other devices as well)
  • The Engine ECU lights the Malfunction Indicator Lamp (MIL) (a.k.a. "Check Engine Lamp") on the dashboard. (In some cases it does so immediately, in some cases after it receives the same DTC twice.)

Fault codes begin with one of four letters, depending of the 2 Most Significant bits (MSb) of the hex code:

  • Ltr MSBs
  • P 00 Most faults start with this letter
  • C 01 Faults in the transmission control ECU or electric power steering system
  • B 10 Smart entry and Immobilizer malfunction. The only DTCs are B1294 and B2799
  • U 11 The Hybrid Control System cannot communicate with other components on the CAN bus

Probably, the letter codes don't stand for types of faults, but are just the letters that happen to appear on the diagnostic tools that car mechanics use.


The battery ECU may generate the following Fault Codes (DTCs = Diagnostic Trouble Codes).

Code (hex) Cause Note


P0560 There's no voltage at the "AM" contact of the battery ECU (it should be 12 V at all times) (1)
P0A1F Battery ECU is bad (many possible symptoms) (2)
P0A7F One of the blocks in the battery pack has deteriorated: its dynamic resistance is too high (1)
P0A80 The difference in voltage between 2 of the blocks in the battery pack is too high (1)
P0A81
P0A82
P0A85
The fan cooling the battery pack has problems (motor voltage or expected battery temperature) (1)
P0A95 Battery pack's fuse is blown (the Service Plug is still plugged in) (3)
P0A9B One of the temperature sensors in the battery pack is opened or shorted (1)
P0AAC The temperature sensors in the air intake is opened or shorted (1)
P30xx Battery block xx - 10 is weak (2)(4)
P3030 One or more of the wires between the Battery ECU and the battery blocks is disconnected (1)
P3056 There's a problem with the battery current sensor (1)

Notes:

  1. Behavior: lets the vehicle go into the READY mode and drive normally
  2. Behavior: lets the vehicle go into the READY mode but limits driving to fail-safe mode
  3. Behavior: if the engine happened to be on at the time, the vehicle remains in the READY mode and continues driving with just the engine; if the engine happened to be off at the time, without a battery it can't be started, so the vehicle turns off the READY mode and stops
  4. There are 14 blocks in the battery pack (1 through 14); the last 2 digits of the code are the equal to the number of the bad block plus 10; so, if block 1 is bad, the code is P3011, if block 12 is bad, the code is P3022


General Disclaimer:   (HV) (DC) injury or death hazard,   use at your own risk,   may void warranty.

HV (High Voltage) DC (Direct Current) Warning: Traction Battery Packs, Motors, Chargers, and other HV sources could cause serious injury or death if proper precautions are not taken while working on or around such High Voltage Direct Current sources.

Use this information at your own risk: There is no warranty expressed nor implied and we are not liable for any of your past, present, nor future actions. Even should you perform these modifications to the letter you could still damage any number of components in your vehicle causing it to no longer function. Even if it appears to function properly your actions may cause it to self destruct with collateral damage to surrounding properties other than your vehicle. By utilizing these ideas and instructions in an attempting to enhance national security, reduce gas consumption, vehicle "emissions", your carbon footprint, or smog, you do so at your own risk & peril.

Warranty: In performing some of these modifications you may void your warranty with the vehicles manufacturer.

See also our My wiki:General disclaimer