If you want to make Split Invoices in OpenERP(Odoo) follow the below mentioned steps:
Step-1Install 10n_ve_split_invoice module.
Step-2 After that we have to customised 10n_ve_split_invoice module.
In below example, I have custmozied .py file. You can directly copy the below python code in 10n_ve_split_invoice module.

class account_invoice(osv.osv):
    _inherit = 'account.invoice'

    def split_invoice(self, cr, uid, ids):
        """ Split the invoice when the lines exceed the maximum set for the company
        """
        for inv in self.browse(cr, uid, ids):
            inv_id = False
            if inv.company_id.lines_invoice < 1:
                raise osv.except_osv(_('Error !'), _('Please set an invoice lines value in:\nAdministration->Company->Configuration->Invoice lines'))
            if inv.type in ["out_invoice", "out_refund"]:
                if len(inv.invoice_line) > inv.company_id.lines_invoice:
                    lst = []
                    invoice = self.read(cr, uid, inv.id, ['name', 'type', 'number', 'supplier_invoice_number', 'comment', 'date_due', 'partner_id', 'partner_contact', 'partner_insite', 'partner_ref', 'payment_term', 'account_id', 'currency_id', 'invoice_line', 'tax_line', 'journal_id', 'period_id', "user_id"])
                    invoice.update({
                        'state': 'draft',
                        'number': False,
                        'invoice_line': [],
                        'tax_line': [],
                    })
                    # take the id part of the tuple returned for many2one fields
                    invoice.pop('id', None)
                    for field in ('partner_id',
                            'account_id', 'currency_id', 'payment_term', 'journal_id', 'period_id', 'user_id'):
                        invoice[field] = invoice[field] and invoice[field][0]

                    #~ if hasattr(inv,'sale_ids'):
                        #~ if self.browse(cr,uid,inv.id,context={}).sale_ids:
                        #~ invoice.update({
                        #~ 'sale_ids':[(6,0,[i.id for i in self.browse(cr,uid,inv.id,context={}).sale_ids])]
                        #~ })

                    inv_id = self.create(cr, uid, invoice)
                    cont = 0
                    lst = inv.invoice_line
                    while cont < inv.company_id.lines_invoice:
                        lst.pop(0)
                        cont += 1
                    for il in lst:
                        self.pool.get('account.invoice.line').write(cr, uid, il.id, {'invoice_id': inv_id})
                    self.button_compute(cr, uid, [inv.id], set_total=True)
            if inv_id:
                self.button_compute(cr, uid, [inv_id], set_total=True)
#                wf_service.trg_validate(uid, 'account.invoice', inv_id, 'invoice_open', cr)
        return True

    def action_date_assign(self, cr, uid, ids, *args):
        """ Return assigned dat
        """
        super(account_invoice, self).action_date_assign(cr, uid, ids, *args)
        self.split_invoice(cr, uid, ids)
        return True

account_invoice()