Conductive Polymer Hybrid Aluminum Electrolytic Capacitors Target HEVs, EVs

The larger current-handling capability of the ZS series capacitors from Panasonic helps contribute to miniaturization.

 

By Murray Slovick, Contributing Editor

With the growing demand for eco-friendly cars, energy efficiency, and the need to comply with environmental regulations, vehicles are rapidly shifting from gasoline-power to hybrid-electric and fully-electric operation. At the same time, vehicle systems that traditionally run directly from the powertrain are giving way to electrification by means of a 48-V battery bus and the integration of mechanical and electrical components.

That reconfiguration involves switching from mechanical to motor drive and electronic control. Among systems yielding to electrification include an integrated starter generator (ISG), electric power steering (EPS), the oil-pump electronic control unit (ECU), water-pump ECU, transmission ECU, radiator fan control (RFC), etc.

What’s more, mechanical drive components and the ECU used to be physically separated and interconnected via cables.  However, demand for high-precision control, more freedom in component layout, fewer cables, etc., has led to the adoption of an integrated configuration of these mechanical and electrical components.

The resulting changes have increased the need to miniaturize and reduce the weight of ECUs and stabilization measures for power-supply circuits in response to increases in current values. Capacitors mounted in power-supply circuits are now increasingly required to feature a larger current and capacity.

Responding to these requirements, Panasonic developed the surface-mounted ZS Series conductive polymer hybrid aluminum electrolytic capacitors with a diameter of only 10 mm and height of 16.5 mm. It’s a first for the industry for automotive use, according to the company.

Shown is a structure diagram of Panasonic’s ZS series. The devices feature a capacity 1.8 times that of its previous product.

By employing a larger current—63 V, 3500 mA (2.5 times that of Panasonic’s conventional products)—and a larger capacity (capacity value: 63 V, 150 µF, 1.8 times that of Panasonic’s conventional products), the devices contribute to the miniaturization and weight reduction of automotive ECUs.

The new products have achieved a larger capacity than conventional products by increasing the aluminum foil area. This was accomplished through the adoption of a unique aluminum foil material technology and a new structural design. It’s expected to decrease the quantity of capacitors and required board space, contributing to ECU miniaturization and weight reduction.

In the past, it was difficult for conventional products, with a maximum size of 10 mm in diameter and 10.2 mm in height, to correspond to a larger current of 100 to 200 A. By adopting a new structure and a polymer impregnation method, these new products, with a size of 10 mm in diameter and 16.5 mm in height, lower the capacitor’s internal resistance value, achieving a current larger than conventional products.

According to Panasonic, the capacitors also exhibit excellent vibration resistance (vibration acceleration is 30 G, approximately three times that of Panasonic’s conventional products). Vibration resistance eliminates the need for anti-vibration reinforcement during the mounting processes, allowing customers to streamline their production processes. The conventional ECU board-mounting process requires anti-vibration measures, such as anchoring components with adhesives, to make the ECU resistant to vibration. The new capacitors are said to have achieved anti-vibration performance high enough to make such anti-vibration measures unnecessary.

 

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