ANNEX 7

Test Procedures for the protection of the occupants of vehicles operating on electrical power from high voltage and electrolyte spillage

This annex describes test procedures to demonstrate compliance to the electrical safety requirements of paragraph 5.5. For example, megohmmeter or oscilloscope measurements are an appropriate alternative to the procedure described below for measuring isolation resistance. In this case it may be necessary to deactivate the on-board isolation resistance monitoring system.

Before the vehicle impact test conducted, the high voltage bus voltage (Vb) (see figure 1) shall be measured and recorded to confirm that it is within the operating voltage of the vehicle as specified by the vehicle manufacturer.

1. Test set-up and equipment

If a high voltage disconnect function is used, measurements are to be taken from both sides of the device performing the disconnect function.

However, if the high voltage disconnect is integral to the REESS or the energy conversion system and the high-voltage bus of the REESS or the energy conversion system is protected according to protection degree IPXXB following the impact test, measurements may only be taken between the device performing the disconnect function and the electrical loads.

The voltmeter used in this test shall measure DC values and have an internal resistance of at least 10 ΜΩ.

2. The following instructions may be used if voltage is measured. After the impact test, determine the high voltage bus voltages (Vb, V1, V2) (see figure 1). The voltage measurement shall be made not earlier than 5 seconds but not later than 60 seconds after the impact. This procedure is not applicable if the test is performed under the condition where the electrical power train is not energised.

3. Assessment procedure for low electrical energy

Prior to the impact a switch S1 and a known discharge resistor Re is connected in parallel to the relevant capacitance (ref. figure 2).

Not earlier than 5 seconds and not later than 60 seconds after the impact the switch S1 shall be closed while the voltage Vb and the current Ie are measured and recorded. The product of the voltage Vb and the current Ie shall be integrated over the period of time, starting from the moment when the switch S1 is closed (tc) until the voltage Vb falls below the high voltage threshold of 60 V DC (th). The resulting integration equals the total energy (TE) in joules:

(a)

When Vb is measured at a point in time between 5 seconds and 60 seconds after the impact and the capacitance of the X-capacitors (Cx) is specified by the manufacturer, total energy (TE) shall be calculated according to the following formula:

(b) TE = 0,5 × Cx ×(Vb 2 – 3 600)

When V1, V2 (see figure 1) are measured at a point in time between 5 seconds and 60 seconds after the impact and the capacitances of the Y-capacitors (Cy1, Cy2) are specified by the manufacturer, total energy (TEy1, TEy2) shall be calculated according to the following formulas:

(c) TEy1 = 0,5 × Cy1 × (V1 2 – 3 600) TEy2 = 0,5 × Cy2 × (V2 2 – 3 600)

This procedure is not applicable if the test is performed under the condition where the electrical power train is not energised.

4. Physical protection

Following the vehicle impact test any parts surrounding the high voltage components shall be, without the use of tools, opened, disassembled or removed. All remaining surrounding parts shall be considered part of the physical protection.

The Jointed Test Finger described in Appendix 1 figure 1 shall be inserted into any gaps or openings of the physical protection with a test force of 10 N ± 10 per cent for electrical safety assessment. If partial or full penetration into the physical protection by the Jointed Test Finger occurs, the Jointed Test Finger shall be placed in every position as specified below.

Starting from the straight position, both joints of the test finger shall be rotated progressively through an angle of up to 90 degrees with respect to the axis of the adjoining section of the finger and shall be placed in every possible position.

Internal barriers are considered part of the enclosure.

If appropriate a low-voltage supply (of not less than 40 V and not more than 50 V) in series with a suitable lamp should be connected, between the Jointed Test Finger and high voltage live parts inside the electrical protection barrier or enclosure.

4.1. Acceptance conditions

The requirements of paragraph 5.5.1.3. shall be considered to be met if the Jointed Test Finger described in Appendix 1, figure 1 is unable to contact high voltage live parts.

If necessary a mirror or a fiberscope may be used in order to inspect whether the Jointed Test Finger touches the high voltage buses.

If this requirement is verified by a signal circuit between the Jointed Test Finger and high voltage live parts, the lamp shall not light.

5. Isolation resistance

The isolation resistance between the high voltage bus and the electrical chassis may be demonstrated either by measurement or by a combination of measurement and calculation.

The following instructions should be used if the isolation resistance is demonstrated by measurement.

Measure and record the voltage (Vb) between the negative and the positive side of the high voltage bus (see figure 1):

Measure and record the voltage (V1) between the negative side of the high voltage bus and the electrical chassis (see figure 1):

Measure and record the voltage (V2) between the positive side of the high voltage bus and the electrical chassis (see figure 1):

If V1 is greater than or equal to V2, insert a standard known resistance (Ro) between the negative side of the high voltage bus and the electrical chassis. With Ro installed, measure the voltage (V1’) between the negative side of the high voltage bus and the vehicle electrical chassis (see figure 3). Calculate the isolation resistance (Ri) according to the formula shown below.

Ri = Ro*(Vb/V1’ – Vb/V1) or Ri = Ro*Vb*(1/V1’ – 1/V1)

Divide the result Ri, which is the electrical isolation resistance value (in Ω) by the working voltage of the high voltage bus in volt (V).

Ri (Ω/V) = Ri (Ω)/Working voltage (V)

If V2 is greater than V1, insert a standard known resistance (Ro) between the positive side of the high voltage bus and the electrical chassis. With Ro installed, measure the voltage (V2’) between the positive side of the high voltage bus and the electrical chassis (see figure 4).

Calculate the isolation resistance (Ri) according to the formula shown below.

Ri = Ro*(Vb/V2’ – Vb/V2) or Ri = Ro*Vb*(1/V2’ – 1/V2)

Divide the result Ri, which is the electrical isolation resistance value (in Ω) by the working voltage of the high voltage bus in volt (V).

Ri (Ω/V) = Ri (Ω)/Working voltage (V)

Note: The standard known resistance Ro (Ω) should be the value of the minimum required isolation resistance (Ω/V) multiplied by the working voltage of the vehicle plus/minus 20 per cent. Ro is not required to be precisely this value since the equations are valid for any Ro; however, an Ro value in this range should provide a good resolution for the voltage measurements.

6. Electrolyte spillage

Appropriate coating shall be applied, if necessary, to the physical protection in order to confirm any electrolyte leakage from the REESS after the impact test.

Unless the manufacturer provides means to differentiate between the leakage of different liquids, all liquid leakage shall be considered as the electrolyte.

7. REESS retention

Compliance shall be determined by visual inspection.