Control technology advantages demonstrated by "a big battery"

We will strengthen the power storage business as another pillar of the energy business after solar cells, consumer rechargeable batteries and car rechargeable batteries. Panasonic expects the global power storage market to reach a scale of about 2 trillion yen in fiscal 2020. Our sales in fiscal 2011 were about 10 billion to 20 billion yen, and our goal is to increase it to 50 billion yen in fiscal 2015.

The reason why the power storage business is worth looking forward to is that in addition to the market growth, it can also produce technology that can "use batteries freely". The large-scale power storage system we provide includes a power storage module equipped with 312 18650-size cylindrical lithium-ion rechargeable battery cells, and a battery control unit that controls the linkage with the system and charging and discharging. By combining them appropriately, it can support various scales (Figure C-1).

Figure C-1: Storage module control technology plays a core role

The large-scale power storage system business uses power storage modules that are composed of cylindrical lithium-ion rechargeable batteries. The technology that controls the charging and discharging of a large number of power storage modules and the linkage with the system will help differentiate the product.

The 1.5MWh storage system (commonly known as "megawatt battery") introduced by the on-board rechargeable battery factory "Kasai Green Energy Park" uses a combination of about 1,000 storage modules. The battery control unit group designed to operate multiple modules in conjunction can manage the charging and discharging of each battery while observing the actions of a total of more than 300,000 batteries. In this way, all batteries can be used as a virtual large battery. Although the performance of the built-in lithium-ion rechargeable battery is also important, we have a greater advantage in control technology. Regarding battery control of the storage system, we have applied for 71 patents in Japan alone.

We currently use self-produced lithium-ion rechargeable batteries, but of course, external procurement is also an option. However, it is an indisputable fact that the close exchange of information with the rechargeable battery business department has contributed to the accumulation of battery control technology. In the second half of 2013, we plan to start production of a storage system using automotive lithium-ion rechargeable batteries. By then, battery control technology will also need to change. At present, as batteries continue to improve, our advantages in the battery business can be applied to the storage system business.