By default, the Divi Theme's Accordion Module will have the first Accordion opened when the Page loads.
This will help you keep all the Accordions in a Closed state by default when the page loads.
If you want this for only specific Accordion modules then go to that Accordion Module Settings > Advance > Custom CSS Class
Use this as CSS Class: my_accordion
Then go to WordPress Dashboard > Divi > Theme options > Integration > <head> section, add this Script there:
<script>
jQuery(document).ready(function() { jQuery('.et_pb_module.et_pb_accordion.my_accordion .et_pb_accordion_item.et_pb_toggle_open').addClass('et_pb_toggle_close').removeClass('et_pb_toggle_open');
});
</script>
This will close the Accordion modules when the page loads for the Accordion modules in which you have used the same CSS Class: my_accordion
If you want this for all Accordion modules though out your site, then you don't need to define any CSS Class and directly use this Script in Theme options > Integration > <head> section:
<script>
jQuery(document).ready(function() { jQuery('.et_pb_module.et_pb_accordion .et_pb_accordion_item.et_pb_toggle_open').addClass('et_pb_toggle_close').removeClass('et_pb_toggle_open');
});
</script>
This will adjust all the accordion modules of your site without requiring to define any custom CSS class to the module.