diff --git a/contracts/tokens/erc721/BEBadge.sol b/contracts/tokens/erc721/BEBadge.sol
index 8ff06f1..2f1969c 100644
--- a/contracts/tokens/erc721/BEBadge.sol
+++ b/contracts/tokens/erc721/BEBadge.sol
@@ -12,6 +12,7 @@ contract BEBadge is AccessControl, ERC721Enumerable {
   bytes32 public constant LOCK_ROLE = keccak256("LOCK_ROLE");
   uint256 public immutable supplyLimit;
   uint256 tokenIndex;
+  uint256 public maxBatchSize = 500;
 
   event Lock(uint256 indexed tokenId);
   event UnLock(uint256 indexed tokenId);
@@ -46,7 +47,8 @@ contract BEBadge is AccessControl, ERC721Enumerable {
     address to,
     uint256 count
   ) external onlyRole(MINTER_ROLE) returns (uint256[] memory) {
-    require(count <= 100, "tokenIds too many");
+    require(count > 0, "tokenIds too small");
+    require(count <= maxBatchSize, "tokenIds too many");
     if (supplyLimit > 0) {
       require(
         (totalSupply() + count) <= supplyLimit,
@@ -126,13 +128,6 @@ contract BEBadge is AccessControl, ERC721Enumerable {
     emit UnLock(tokenId);
   }
 
-  /**
-   * @dev Get lock status
-   */
-  function isLocked(uint256 tokenId) external view returns (bool) {
-    return lockedTokens[tokenId];
-  }
-
   /**
    * @dev Set token URI
    */
@@ -142,6 +137,11 @@ contract BEBadge is AccessControl, ERC721Enumerable {
     _metaAddress = metaAddress;
   }
 
+  function updateDuation(uint256 valNew) external onlyRole(DEFAULT_ADMIN_ROLE) {
+    require(valNew > 1, "batch size too short");
+    maxBatchSize = valNew;
+  }
+
   /**
    * @dev one type badge has same tokenURI
    */