Climate change has already affected the whole world with extreme weather conditions, which has led over 130 countries and regions to announce their goal of carbon neutrality. For this reason, renewable energy has experienced rapid development in recent years, but the volatility and intermittency of renewable energy also cause problems with grid stability. More and more countries are incentivizing energy storage systems and combining solar and storage systems is becoming a trend, leading to a growing market for battery systems. However, customers have to confront the challenges and difficulties such as safety, energy mismatch, maintenance etc.
Main challenges of residential batteries
Energy capacity mismatch
For a 48V low voltage battery system, multiple battery packs are connected in parallel at 40-60V. The charging current is different for each battery pack because of the internal resistance difference. The battery with high internal resistance will receive a lower charge current, which may result in not being able to fully charged for a long period of time and eventually cause the battery to lose capacity.
In a high-voltage battery system, several battery packs are connected in series, which equalizes the charge/discharge current of each battery. However, due to the uneven capacity of the batteries, the lower capacity batteries are fully charged/discharged faster than others and trigger the whole system shutdown, resulting in other batteries notbeingable to be fully charged and discharged for as long. This eventually leadsto a loss of capacity of the battery.
Difficulty of maintenance
The whole battery system shut down once a battery pack is defective and cannot provide continuous power, requiring field installers to replace the defective battery pack. Typically, installers must remove the defective battery and reinstall thebattery systemwithacomplicated process: charge the entire battery system to 100% SoC, and use a DC power source to separately charge the new battery to 100% so that all batteries have the same SoC. Finally, install the new battery pack into the existing battery system. The whole process takes hours or even 1 to 2 days, which is terrible for customers experience and brings high cost.
Disable to mix the new and old batteries
In a low-voltage battery system, the mixed use of new and old batteries leads to internal circulation due to the different resistance of the battery cells, which accelerates the aging of the battery. In a high-voltage battery system, the mixed use of newandoldbatteries leads to the barrel effect, i.e., the capacity of the new batteries is used at the same capacity level as that of the old batteries, resulting in a loss of capacity of the system. Consequently, the battery suppliers always claim that the old and new batteries cannotbe mixed or just beable to mix within 6 months.
Challenge of battery cell shortage
The upsurge of residential ESS and EV markets leads to a shortage of battery cells, it causes the battery suppliers have to search different cell manufacturersto guarantee delivery. However, it’s not permitted to combine the battery packs with different cells, which leads to the big challenges of inventory management.
Growatt innovative APX HV Battery GROWATT’s new APX HV Battery
adopts the advanced battery soft-switching parallel connection technology enables to mix batteries from different batches, suppliers, specifications and capacities during the sales, installment and maintenance processes, which results in the following advantages: 1) easy sales which is popular with distributors, system integrators and installers due to its wide compatibility and convenient after-sales service; 2) easier battery installation and maintenance for installers and electricians due to improved compatibility and flexible battery replacement choices; 3) reduced reliance on certain battery cell suppliers and optimized supply chain cost control in the long term. Main advantages details as below:
Mix battery packs of diverse capacity
Due to the integrated pack level energy optimizer, the battery packs with different capacities can be mixed in one system, each battery pack can contribute the power separately as needed and perform automatic balancing, meaning that each battery can always be fully charged and discharged without the risk of energy mismatch. In addition, no additional recharge process is required to greatly save installation and maintenance lead time.
Mix battery packs of new and old batches
The APX battery packs of new and old batches can be mixed at any time without internal circulation and barrel effect. Users can freely add the additional battery packs to extend storage capacity at any time as needed andreduce the initial investment. It’s alsoconvenient for installers to replace the dedicated failure battery pack with the new one but not replace the whole system.
Mix battery packs with cells from different suppliers
The battery packs with different reliable battery brand cells can work together without performance loss, which reduces reliance on certain battery cell suppliers and optimized supply chain cost control
Additionally, in the event of a battery pack failure, it will not affect other packs and continue to power the house.
Safety always come first
Beside the LFP highly reliable chemistry, APX HV Battery also integrated the five-level protections for the extreme safety: cell level BMS, modular level energy optimizer, system AFCI, passive protection with fuse as well as the built-in aerosol fire extinguishing agent.
One fits all
APX HV Battery can fit single phase battery ready Growatt inverters of MIN 2500-6000TL-XH, MIN 3000- 11400TL XH-US, and three phase MOD 3-10KTL3-XH for residential energy storage system, as well as the upcoming MID 12-30KTL3-XH for commercial energy storage applications.