You want to use a batch jobs so batch jobs should not have password embedded in the command line or script.
You can use Oracle Basic authentication methods for implementing no password login credentials.

sqlplus /nolog

conn / as sysdba
show parameters OS_AUTHENT_PREFIX

os_authent_prefix ops$

Alter system set OS_AUTHENT_PREFIX=’ ‘ scope=spfile;

shu immediate

conn system/oracle
creed user zekeriya identified externally;
grant create session,resource to zekeriya;

operating system zekeriya is OS user
oracle$ su – zekeriya

zekeriya$ sqlplus /

select * from dual;