How to Select DC Relays and Microswitches for Supporting Safety Control of Electric Mobility

1. What are DC relays and microswitches suitable for electric mobility?

With the advent of electric mobility, there are high expectations for the realization of a decarbonized society and new means of transportation to support an aging society. On the other hand, design issues related to practicality are also increasing. The mobility industry requires designs that take into account greater safety, energy efficiency, design, and functionality.
DC relays and microswitches suitable for electric mobility are components that can stably energize and interrupt DC loads even under vibration and shock. Furthermore, the low power consumption and small size of these components will make them more valuable for mobility. Therefore, it is important to select these components from the three perspectives: "stable energizing and interruption", "low power consumption", and "miniaturization”.

Sharing economy, Decarbonized society, Aging society: Electric mobility {Design Challenges faced by engineers: Safety & Reliability Safe driving in various situations; Value required for components: (1)Stable energizing and interruption; OMRON's recommended electronic components: DC relay} {Design Challenges faced by engineers: Energy-Saving Improved mileage; Value required for components: (2)Low power consumption; OMRON's recommended electronic components: DC relay / Microswitch} {Design Challenges faced by engineers: Design & Functionality Compact & slim; Value required for components: (3)Miniaturization; OMRON's recommended electronic components: Microswitch}

*1 If you are considering using them for automotive applications, please refer to the Automotive Relays and Automotive Switches web pages.

2. Are you having trouble with these things?
  - Selection points for components to address engineers' concerns

In electric mobility, design issues include stable energization and interruption of DC loads to have stable electric control, realization of low power consumption drive for high energy efficiency, and miniaturization and weight reduction of mechanisms to achieve both design and functionality.
The following three points need to be considered for selecting DC relays and microswitches to solve each problem.

  • (1) Ability to energize and interrupt DC loads stably even under vibration and shock conditions
  • (2) Eliminating wasteful power consumption
  • (3) Thoroughly small in size

Examples of problems faced by engineers

We want to realize safety control of DC loads in various driving environments.

Icon representing human-centric design in modern electric mobility solutions.

"Larger battery capacity. Is that DC load control really safe?"





Directional arrow graphic for desktop layout showing the flow of power in EV systems. Directional arrow graphic for mobile layout showing the flow of power in EV systems.

Selection point (value provided by OMRON)

Stable energizing and interruption even under vibration and shock

Infographic: Energy management and efficiency in electric vehicle powertrains.

Examples of problems faced by engineers

We want to realize low power consumption design while maintaining/improving functionality

"People talk about energy savings, but we have to add the ability to interrupt large loads..."

Selection point (value provided by OMRON)

Waste-free power consumption


Infographic: Safety and reliability components for battery management systems (BMS).



Examples of problems faced by engineers

We want to achieve both functionality and design

"We want functionality, but we also want a slim, compact design..."





3. DC relays and microswitches for electric mobility recommended by OMRON

Introduced separately for DC relays (high capacity), DC relays (low capacity), and microswitches are: OMRON's recommended products that meet the needs of "stable energizing and interruption", "low power consumption", and "miniaturization".

3-1. DC relays (high capacity range)

Electric mobility has three major components: charging device, battery (DC power source), and DC load. DC relays are required to play two roles, one for interrupting and the other for pre-charging. This is an application where safety is strongly required.

System diagram: High-voltage DC relay application in an electric vehicle charging circuit.

*2 To learn more about our recommendations in chargers, please visit Solutions for Energy Market.

For emergency interruption and pre-charge applications
-- Choose the G9E□ series

[Stable energizing and interruption] To safely energize and interrupt DC loads even under vibration and shock conditions

G9EK-1

Rated load: 500 VDC/120 A

G9EK-1-E

Rated load: 500 VDC/200 A

G9EK-1-EX

Rated load: 500 VDC/250 A

Application image: OMRON DC power relays installed in a compact EV battery pack.
Materializing shocking "shockproof performance"

No malfunction even in shocks up to 100 G*3 that occur in short shutdowns.
 

Shock resistance performance when energized G9EK-1 [G]

Energized

Note: Dimensions are in mm (typical value)
*3 The impact of a 350 km/h car coming to a stop in 0.1s is about 100 G.

[Miniaturization] For a small size and high inrush resistance for pre-charge applications

G9EJ

Rated load: 400 VDC/15 A

G9EJH

Electrical endurance (condenser load): 800 VDC/30 A
 

Technical detail: Arc-extinguishing technology in high-capacity DC relays.
"High inrush resistance + long life" that can be achieved even with a small size

Combines high inrush resistance and electrical durability despite its small size.
(Guaranteed 100,000 times at 400 VDC/25 A)

Example of Reference Data G9EJ-1

(1) Operating voltage fluctuation rate x Number of electrical endurance cycles*6

Operating voltage fluctuation rate of less than 3% even after 100,000 endurance cycles

(2) Voltage drop value x Number of electrical endurance cycles*7
 

Operating voltage drop of less than 100 mV even after 100,000 endurance cycle

Note: Dimensions are in mm (typical value)
*6 Measured at 400 V/25 A, 100,000 test cycles, normal temperature and humidity, 3300 µF capacitor load, n = 3
*7 Measured with voltage value at 15 A energization, n = 3
Note: The values are actual values and are not guaranteed.

[Low power consumption] To achieve both high-capacity interruption/control and power saving

G9EK-1

Rated load: 500 VDC/120 A

G9EK-1-E

Rated load: 500 VDC/200 A

G9EK-1-EX

Rated load: 500 VDC/250 A

Application image: OMRON DC power relays installed in a compact EV battery pack.
Low power consumption despite high short-circuit performance

It has a high short-circuit performance of 5000 A, yet consumes only 4 W.
 

Example of Reference Data G9EK-1-U

Chart showing the compact size and weight advantages of OMRON automotive relays.

Note: Dimensions are in mm (typical value)
*4 Comparison of short-circuit performance between G9EA (approx. 2000 A) and G9EK-1-U (approx. 5000 A)
*5 Comparison of power consumption between G9EA (approx. 5 W) and G9EK-1-U (approx. 4 W)

(Informative) OMRON's main lineup of high capacity DC relays (by rated load)

Note: If you are considering using them for automotive applications, please refer to the Automotive Relays web page.

3-2. DC relays (low capacity range)

DC relays are also used for applications in the low capacity range (e.g., control of motors, fans, and heaters). Since these applications require strict design in a limited space, relays are characterized by their high switching capacity and thorough miniaturization requirement at the same time (minimization of the volume and area).

Application: Reliability-focused switches and sensors for electric wheelchairs. Application: Reliability-focused switches and sensors for electric wheelchairs.
Desktop view: Evolution of electric mobility from micro-mobility to heavy machinery. Mobile view: Evolution of electric mobility from micro-mobility to heavy machinery.

Example of motor control circuit

Environmental testing: Components performing in extreme temperature and vibration.

Example of fan control circuit

Application: Waterproof microswitches used in outdoor e-bike control units.

For motors, fans, heaters, and other applications
-- G8□ series

[Miniaturization] To achieve both minimum mechanism and high electric load control

G8K

Rated load: 14VDC/5A
 

Data graph: Electrical life endurance of relays under high-inrush current loads.
Outstanding! Industry's smallest class*8 ultra-compact DC relay

・Unique structural design realizes ultra-compact size (specialized for short-time energization).
・The terminal arrangement simplifies PCB wiring and enables ultra-high-density mounting in positive and negative circuits.

Conceptual image of PCB pattern using typical relays (bipolar) / Conceptual image of PCB pattern using G8K-2

Note: Dimensions are in mm (typical value)
*8 According to OMRON's research in October 2023

[Miniaturization] To achieve a high heat dissipation design with less than conventional PCB size

G8G

Rated load: 14 VDC/35 A
                     28 VDC/14 A

Visualization of noise reduction in silent automotive relays for passenger comfort.
Compact DC relay with "small footprint"

Reduced relay footprint enables high heat dissipation design
 

Reduced footprint G8G

Note: Dimensions are in mm (typical value)
(Rated voltage: For 12 VDC model)

[Stable energization and miniaturization] To achieve both stable energization in various environments and minimization of the mechanism

G8PM

Rated load: 14 VDC/45 A
 

Application: High-current connectors for electric vehicle charging ports.
Unique twin contact structure for high current-carrying reliability
  - "Capacity of 40 to 60 A, yet this small"

・Improved contact reliability with a structure that stabilizes contact resistance.
・Compact design with high heat dissipation characteristics.
・Latching model available. Contributes to power saving applications.

Typical shape / G8PM

Large heat radiation area allows dispersion of heat load

Note: Dimensions are in mm (typical value)

(Informative) OMRON's main lineup of low capacity DC compact relays

Comparison: OMRON high-voltage DC relays vs. traditional contactors for weight savings.

Note:

The above is for a resistive load.
Refer to the datasheet on the detail page for more information.

Note: If you are considering using them for automotive applications, please refer to the Automotive Relays web page.

3-3. Microswitches

Electric mobility requires a variety of detection mechanisms to support the application in order to enhance functionality. Examples include charger connection detection, battery connection/disconnection detection, maintenance hatch open/close detection, door lock status detection, and key insertion detection. OMRON's D2□W series are dustproof and waterproof (equivalent to IP67*11) microswitches that are available in a wide range of products for various applications. Select the optimum product for your application in terms of load capacity, stroke, mounting type, terminal shape, etc.

*11 Protrusions not included

For object movement and position detection applications
-- D2□W series

[Miniaturization] To minimize the detection mechanism and add functions in a small space

D2EW
 

 

Thermal simulation of heat dissipation in high-capacity PCB-mounted relays.
No lever needed! "Onigiri-shaped switch" for multi-angle operation

Small microswitch for operation from the top, left, and right minimizes the detection mechanism.

Sustainability goals: How electric mobility components contribute to carbon neutrality.

Note: Dimensions are in mm (typical value)

[Safety] To add functions of normal system operation verification/anti-theft/early identification of failure modes

D2AW-R/D2EW-R

 

Sustainability goals: How electric mobility components contribute to carbon neutrality.
Detection of four states by internal resistor Long stroke sealed switch.

Four states (switch ON/OFF, short circuit, open circuit) are output.

Technical white paper thumbnail: Reliable switching for 800V EV battery systems.

Note: Dimensions are in mm (typical value)

[Design simplification] To make mechanism design easier

D2QW
Without a lever / With a lever
Easy design with long operating stroke!

・2.7 mm without lever, 3.5 mm with lever*12
・Lever shape modification according to the application is also possible.

D2SW:OP〜TPP=0.5mm / D2QW:OP〜TPP=2.7mm So much design leeway without levers!

Note: Dimensions are in mm (typical value)
*12
The OT (movement after operation) value is the distance from OP (operating position) to TTP (operation limit position).
It depends on the type of lever.
Please contact us for lever shapes that are not included in the models.

(Informative) OMRON's main lineup of sealed microswitches (by rated load and stroke)

Application guide for selecting switches and sensors in autonomous delivery robots.

Note:

・Rated load is for resistive load.
・The OT (movement after operation) value is the distance from OP (operating position) to TTP (operation limit position). The above is for those without a lever. (D2FW-G is a leaf lever model)
・We will consider modifications for specifications not listed in the catalog. Please contact us.

Note: If you are considering using them for automotive applications, please refer to the Automotive Switches web page.

4. Recommended products by application

We can offer a wide range of product lineup for various types of electric mobility. Other OMRON products not mentioned above are also available for your consideration.

Electric mobility examples

Application icon: Component solutions for electric golf carts and utility vehicles.

Electric cart

Electric wheelchair

Application icon: Heavy-duty relays for electrified agricultural tractors.

Electric agricultural machinery

Application icon: Ruggedized sensors for electric construction excavators.

Electric construction machinery

Application icon: Compact switches and sensors for e-bikes and pedelecs.

Electric bicycle

Application icon: Sensing and switching for autonomous last-mile delivery robots.

Delivery robot

Application icon: Tactile switches and ToF sensors for smart home robotics.

Robot cleaner

Application icon: Safety and navigation components for AGVs and AMRs.

AGV

Application icon: Reliable components for shared e-scooter fleets.

Electric scooter

Application icon: High-capacity relays for electric industrial forklifts.

Electric forklift truck

Note: You need to confirm legal requirements for electric mobility.
Please contact us to discuss your requirements for components.

● Battery management

・Emergency interruption (DC)

G9EA Product: OMRON G9EA High-voltage DC Relay for power line disconnection.
G9EC Product: OMRON G9EC High-capacity DC Relay for industrial mobility.
G9EK Product: OMRON G9EK compact DC power relay for auxiliary circuits.
G9EH Product: OMRON G9EH high-voltage relay for on-board chargers (OBC).
G9EK-1
G9EK-1-E

Link to detail page: G9EA, G9EC, G9EH, G9EK-1, G9EK-1-E

・Precharge application (DC)

G9EJ Product: OMRON G9EJ DC power relay for pre-charge circuits.
G9EJH G9EJH

Link to detail page: G9EJ, G9EJH

● Various control applications (for PCB-mounted relays)

・Motor control: Power seat, etc.

・Fan control: Blower fan, etc.

・Heater control: PTC heater, etc.

・Lamp control: Headlamp, position lamp, etc.

G8K
Product: OMRON G8K ultra-miniature automotive PCB relay.
G8PM
Product: OMRON G8PM automotive relay for high-current switching.
G8G
Product: OMRON G8G relay for heavy-duty automotive applications.

Link to detail page: G8K, G8PM, G8G

● Controls/input devices

Speed control, direction change detection, grip detection, key cylinder detection, parking brake detection


D2HW Product: OMRON D2HW sealed subminiature switch for door locks.
D2AW Product: OMRON D2AW sealed switch with long-stroke sliding contacts.
D2QW Product: OMRON D2QW ultra-subminiature sealed slide switch.
D2GW Product: OMRON D2GW low-load sealed switch for automotive sensors.
D2EW Product: OMRON D2EW sealed ultra-subminiature switch for EV chargers.

Link to detail page: D2HW, D2AW, D2QW, D2GW, D2EW

● Mechanism detection

Seat occupancy detection, seatbelt detection
direction change detection, parking brake detection,
battery connection/disconnection detection, charger connection detection

D2HW Product: OMRON D2HW sealed subminiature switch for door locks.
D2AW Product: OMRON D2AW sealed switch with long-stroke sliding contacts.
D2QW Product: OMRON D2QW ultra-subminiature sealed slide switch.
D2GW Product: OMRON D2GW low-load sealed switch for automotive sensors.
D2EW Product: OMRON D2EW sealed ultra-subminiature switch for EV chargers.
D2VW Product: OMRON D2VW basic sealed switch for industrial mobility.

Link to detail page: D2HW, D2AW, D2QW, D2GW, D2EW, D2VW

* We also support the selection of components for equipment and applications other than those listed above. Please contact us for more information.

Related Contents

Click here to learn more about applications and recommended products in chargers

Success Story: OMRON relays in advanced e-scooter battery swap stations.
Success Story: High-reliability switches in autonomous delivery robots.

Click here to learn more about DC power relays

Success Story: OMRON DC power relays in rapid EV charging infrastructure.
Success Story: Optimizing electric wheelchair safety with OMRON sensors.

Click here to learn more about automotive relays

Success Story: Improving drone flight reliability with ultra-light components.
Success Story: Smart sensing for AGVs in high-efficiency warehouse logistics.

Precautions

Please read the following information carefully if you are considering using the product for automotive applications.

Note for sale of Automotive relays/switches and using catalogue

  1. Selling for car makers and companies related to Automotive

    Omron and car makers or companies related to automotive confirm relay specifications and actual using condition to use relays and switches safely. Tests are included when necessary.
    Omron can not sell or guarantee our automotive relays and switches when we have not finished making contracts with Product Specification.

  2. Selling for NO car makers or companies NOT related to automotive, and individual customers

    Basically, Omron can not sell our automotive relays and switches for NO car maker or companies NOT related to automotive. Omron basically can not support for individual customers.

  3. Safety Precautions for All Automotive relays/switches

    When you consider using our automotive relays/switches or see our catalogue, please confirm our Common Precautions in advance.