Battery

Designing Better Cell Connectors: Key to Optimizing Battery Pack Performance

Cell connectors also play a key role in how well a battery performs, especially under real-world conditions.
cell connectors
When it comes to designing a reliable and efficient battery pack, most of the attention tends to go toward cell chemistry, BMS (Battery Management System), and thermal control. But the cell connectors also play a key role in how well a battery performs, especially under real-world conditions.
Whether you’re building a battery for an electric vehicle, an e-bike, a backup power system, or an industrial machine, connector design affects how efficiently power flows, how heat is handled, and how long the pack holds up in service. In this article, we’ll explore why connector design matters, how it works in series and parallel configurations, and why Nickel and Nickel-plated steel are widely used materials for this job.

What Are Battery Cell Connectors?

Battery cell connectors are conductive strips, typically made from metal, that join individual battery cells to form a complete pack. They’re used in two primary configurations:

Series connections:

In a series setup, the positive terminal of one cell is connected to the negative terminal of the next. This increases the total voltage of the pack. Series connections are common in systems that require higher voltage, such as electric cars, e-bikes, and solar battery banks.

Parallel connections:

In a parallel setup, all the positive terminals are linked together, and all the negative terminals are connected together. This increases the total capacity (amp-hours) of the battery. Parallel arrangements are often found in energy storage systems and devices where longer runtimes are needed.

Most real-world battery packs use a combination of both, often arranged in large arrays.
Cell connectors are important because they ensure:

  • Secure electrical contact
  • Low resistance for efficient power transfer
  • Mechanical strength to withstand vibration, thermal expansion, and handling

Choosing the Right Material

The most common materials for cell connectors include copper, aluminium, pure Nickel and nickel-plated steel or copper. Copper and aluminium offer high conductivity, but are less common in welded applications due to production welding, oxidation and cost factors.

Pure Nickel and Nickel-plated steel strike a good balance of performance, durability, and cost, especially in spot-welded or laser-welded packs.

Nickel-plated steel is widely used due to its good conductivity, corrosion resistance, and excellent weldability. The nickel plating reduces contact resistance and provides a clean surface for repeatable welds.
Material choice depends on the application, current loads, expected lifecycle, and manufacturing process.

Electrical Performance: Current Flow and Resistance

In both series and parallel configurations, the efficiency of a battery depends on how well current flows through the connectors. Poor connector design introduces resistance, which leads to voltage drops, power losses, and heat buildup – all of which reduce performance and accelerate cell aging.

Key factors that affect current flow:

  • Connector cross-sectional area (thicker and wider = lower resistance)
  • Material conductivity
  • Weld quality, ensuring consistent electrical contact
  • Path length between connections (shorter paths are better)
For high-current applications, like EV acceleration or motor startup, the connector must be sized to handle the peak load, not just the average current.

Heat Management

Connectors also play a role in thermal performance. High resistance leads to localized heating, which can damage cell terminals or degrade nearby components.

  • Pure Nickel has great conductivity, heat dissipation & corrosion resistance
  • Nickel-plated steel has many of the benefits of pure Nickel whilst also reducing cost.

Battery packs designed for high load or fast charging need careful thermal modelling, including the connector layout. Proper connector design can reduce reliance on active cooling or bulky heat sinks.

Mechanical Integrity and Longevity

Battery packs are exposed to vibration, thermal expansion, and sometimes physical shocks – especially in mobile and outdoor systems like e-scooters, drones, or utility-scale storage. The connectors must maintain electrical contact without cracking, detaching, or loosening over time.

  • Pure Nickel and Nickel-plated steel both provide a good mix of flexibility and strength.


Connector design also impacts assembly time and repeatability. Consistent weld performance is critical for large-scale production or automated pack assembly.

Why Connector Design Matters Across Applications

Here’s how connector design impacts different types of battery systems:
  • EV and e-mobility packs: Often use series-heavy designs to meet voltage requirements; connectors must handle high surge currents.
  • Energy storage systems: Usually rely on parallel configurations to maximize capacity and cycle life; connectors must support sustained discharge over long periods.
  • Industrial and grid-scale systems: Require long-term reliability and strong mechanical bonding, often in difficult environments.
  • Micromobility: Compact packs need precise connector layout to save space while ensuring structural strength.
Regardless of application, good connector design improves efficiency, reduces thermal issues, and extends pack lifespan.

Your Partner in Reliable Battery Cell Connections

Whether you’re connecting cells in series to increase voltage or in parallel to expand capacity, the materials and layout you choose directly affect performance, safety, and reliability.
Nickel and Nickel-plated steel are proven options for a wide range of battery applications. They offer the right balance of conductivity, strength, and manufacturability, especially when spot welding or laser welding is used.

At Datum, we’re a specialist development partner of battery cell connectors for battery pack manufacturers, from prototype through to full-scale production. We manufacture custom connectors on a contract basis for battery packs used in e-bikes, e-scooters, EVs, and stationary storage systems. If you need a reliable, scalable connector solution, we’re ready to help.

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