Shenzhen-based BAK Battery Inc has filed for the second time an invalidation request against Beijing-based E-motor Inc over a lithium battery patent (patent number: ZL200610072849.5) at the China National Intellectual Property Administration (CNIPA), according to the announcement published on the Administration’s Website. In October 2021, BAK filed an invalidation request over the same patent at CNIPA, but the IP office ruled in favour of E-motor and upheld the validity of the patent last year. E-motor lodged lawsuit against BAK previously, accusing the company of infringing the patent at the Beijing Intellectual Property Court. E-motor claimed over 50 million Yuan. It is reported that from the second half of 2019, IP-related lawsuits in the field of lithium battery have increased significantly.