Let's discuss the Power Wall, Tesla's energy storage system. Overall, Tesla’s Powerwall energy storage system has had a huge impact in the solar field, and it has effectively promoted the promotion of household energy storage.

Tesla released the first generation of Powerwall, this integrated energy storage system battery capacity is not too large, 6.4kWh. The figure below is the connection diagram of the first generation.

The second-generation Powerwall 2 has more than doubled the storage capacity and includes an integrated battery charger. The figure below is the connection diagram of the third generation.

In May 2021, Tesla updated Powerwall+ (plus) for this product. The system itself has not changed, but the Powerwall 2 battery system, integrates a solar inverter, making it a complete all-in-one solar Storage System.

The iterative change from the first generation to the second generation has changed the most. Here are a few things:

The thermal management of Tesla Powerwall 2 was also a complete liquid cooling system at the time, using a completely sealed liquid coolant system (including 2.3 liters of liquid coolant). It has the possibility of higher temperature operation. This thermal management system is similar to the car system and can have heating and cooling functions.

From the system point of view, the assembly of Power Wall1 is quite troublesome. At first, Tesla wanted to make a networked system, so some system updates were made at the gateway level from Power Wall1 to Power Wall2.

The Power wall2 update also released solar inverters with liquid cooling and heat management, available in 3.8kW and 7.6kW sizes, and has all safety functions integrated, including quick shutdown, arc fault, and ground fault protection.

The third generation Powerwall+ (Plus) has some slight adjustments to the available capacity and weight. The main update of this system is the Tesla solar inverter with system integration, thus becoming an all-in-one system. The storage capacity remains unchanged at 13.5kWh, and the rated power has been substantially increased to meet the needs of off-grid and backup. The rated power has been increased from 5kW (continuous) and 7kW (peak) to 7kW (continuous) and 10kW (peak) in off-grid mode. The grid-connected rated power also slightly increased to 5.8kW (continuous) and 7.8kW (peak). The specifications of the integrated solar inverter remain unchanged, but from the design point of view, it has been re-adjusted. The figure below shows the third-generation connection.

Power Wall1 uses 18650 cells, after Power Wall uses 21700, the overall system is equipped with a charging and AC/DC inverter, which can be compatible with two different connection methods of DC and AC.

This system is compatible with the previous Powerpack. The first generation is a design with built-in modules, which are placed side by side like Model S modules. In the battery system, the water cooling pipe runs on both sides of the box. The electronic part including the converter and the BMS are arranged in the front compartment. The new design cancels the water-cooling scheme at the system level, and directly puts the batteries together, and then glues them together. From the label point of view, it uses a 900V system, which is made with a large number of cells  potted with thick glue.

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