Products for HVs and EVs

Contributing to Environmental Preservation through Development of Products Supporting Increased Use of Electric Vehicles.

We develop wire harnesses, connecting components, peripheral devices, and other products capable of handling large currents, products that are indispensable for the increasing transition to electrically powered vehicles. These space-saving, lightweight products also provide greater fuctionality.

Under-Floor Pipe Harnesses

High-voltage harness mounted under the floor of electrically motorized vehicle.The use of aluminum pipe achieves space saving, weight reduction, and low cost.


The use of the aluminum pipe for the high-voltage harness satisfies the following functions:

  • Electromagnetic shielding
  • Protection of wire from external environment (like flying stones) while driving.
  • Regulation of the path through flexible adaptation to the route under the floor of the vehicle
  • Excellent heat radiation property, allowing use in the hot area of the vehicle.
  • improving assemblability (facilitating harness assembly workability in vehicle assembly plant)
  • reducing development lead time (Design of molds such as resin protector is not required)

Charging Connector

Used when charging electric vehicles and plug-in hybrid vehicles at user's home or at a charging spot  as a connection between the vehicle and the power supply. By conforming to the standard specified connector configuration, the connector can be used at any charging spot throughout Japan. It has been proved to exhibit sufficient safety performance as a result of repeated experiments based on outdoor use.


In relation to the standards concerning insertion and removal, connection stability was maintained after twice the number of recommended insertions and removals. Furthermore we improved the cable's flexibility and resolved problems with the cable at the time of charging.


Employment of the connection process that secures stable connection after multiple insertion/removal operations conducted outdoors. Employment of the mode for protecting the conductive point in order to obtain IP44 protective classes with respect to water-proof and dust-proof properties.

Battery Wire Module

The high voltage batteries functioning as the  power source of a hybrid vehicle are a bulk material of battery cells (lithium-ion battery). Our battery wire module has a  bus bar set in the  resin case, and by assembling it to the high voltage battery, it enables the battery cells to connect in series. The dedicated terminals/harnesses are installed to detect the voltage of the battery, therefore it enables the connectors to connect with battery's ECU side.


By  consolidating the common fine components, it can be applied to high voltage batteries with different battery cell numbers. Though the bus bar set in the resin cases is bolted to the high voltage battery, the oval holes enable absorption tolerance, and improve the efficiency of the assembly work.

Power Supply BOX

High-voltage battery is installed in the hybrid vehicle (HEV) and the electric vehicle (EV) for motor driving operation. Power supply BOX for HEV is installed in the high-voltage battery, having functional parts such as relay/resistance/fuse/current sensor assembled for supply/cutoff/distribution of the high voltage power supply.


This product optimizes the layout of components such as relays for efficient circuit routing using copper-plate (called "bus bar") to achieve compact/highly integrated structure.


We are able to realize a highly reliable connection by means of the plugin connection of the bus bar (a component made by us which works to give structure to a circuit) and the connecting component used as the relay terminal for function components such as relays.

Terminal Block ,Power Cable

Terminal Block and power cable adapted to unitization of inverter and motor


To cope with unitization of inverter and motor, a low profile is achieved by configuring the terminal into water cutoff type with mold/adhesive. In the case of molding both terminals, and making the wire short, the braided wire of the conventional shield of package type may be disadvantageous in that it has to be preliminarily routed, and is likely to split upon cutting. Those problems are solved by employing the high-density braided wire which secures to keep its shape equally well post-installation. Furthermore, the newly developed wire with flexible wire-coating has solved the problem of operational degradation thanks to the reduced wire length.

Charging-Discharging Controller for System

A charging-discharging converter incorporated in a system which enables reduction of energy consumption when generating electricity, by providing electricity to components when necessary, which is then accumulated when the vehicle slows down, converting kinetic energy to electrical energy.

Properties of Capacitor Charging-Discharging Controller for System manufactured by Sumitomo Wiring Systems

Charging-discharging control: The Charging-discharging cotroller we invented is made to charge and discharge efficiently against a wide change of voltage of the capacitor, by applying the two-way DCDC converter which controls the increase and decrease in pressure.
Quantity Radiation Technology: We applied the PS Board® which is a technology unique to the Sumitomo Wiring Systems , that reduces the increase of temperature of the charging-discharging controller when charging or discharging the capacitor.

High-Voltage Connectors

HV connector for HV Battery, Inverter, Air Compressor, and Charging system Installed in Electric Vehicle , Plug-in Hybrid and Hybrid Vehicles.
Product lineup for the catalog connector will be assorted from 20A to 400A (Some of them are under development at present)


HV connector has optimized functions(Temperature , Vibration, Waterproof, EMC) in consideration of the characteristics of each mounting position.
It has connection reliability and safety that can be used in harsh environment.