Dear friend,
The so called "sick leave" under the SPE Act,1976 in your query is "the leave on medical certificate" allowed u/s 4 (1) (b) of the Act.
For the sake of ready-reference, let me extract the sub-section as follows:
" Sec.4 (1)(b) leave on medical certificate on one-half of the wages for not less than one-eighteenth of the period of service."
If you carefully analyze the sub-section, you will understand that -
(1) It is a leave to be claimed only on the basis of a medical certificate.
(2) The scale of its availment is related to the length of service rendered by the employee in the establishment i.e., not less than 1/18 of the period of service as on the date of application. So the question of maximum limit does not arise.
(3) Since it is a leave with half-the-wages on genuine medical grounds only, the Act does not prescribe any maximum limit on its accrual or availment.
Thus the implication is that there is no question of accumulation of such leave.