Case study at-a-glance Panasonic Energy of North America (PENA) is the largest battery manufacturer in the United States and one of the largest battery factories in the world, producing 5.5 million lithium-ion batteries a day. With a workforce of over 4,500 employees, PENA has delivered more than six billion cells to date. As a recognized innovator in lithiumion battery technology and production, PENA works with ...