If the load is DC that is ok, the direct connection can be established. In special cases there are DC loads. But, most probably the load is AC, then a converter is essential. Hope this helps.

There are two important reasons I can point out.

1. Load requirements, whether the load is AC or DC, Voltage rating of the load etc.

2. The solar radiation is not constant throughout the day. Therefore, to extract maximum power from the solar PV panel, MPPT techniques should be employed, MPPT technique  can be integrated in the DC/DC converter. (When the converters duty cycle varies, the load resistance seen by the converter also varies and at optimum duty cycle maximum power point can be reached).

Therefore, DC/DC converter becomes essential part of the solar PV system. Hope this answer helps.

Note: Pl refer section 2.3 of the following paper.

Apart from above reasons, a short-circuit in load may damage the solar panel internal conducting buses.

The main problem that occurs with connecting the panel to the load is the clouding problem, when a cloud happens to pass the solar panel the power output of the panel will reduce and hence the load will face a reduce in voltage and some equipment may not even function properly. if panels must be connected to the load directly it is possible in an on grid system where the grid compensates for clouding and shading problems of the panel and in an off grid system battery is needed to compensate for power reduction during shading or clouding problems, in either cases an inverter is a must because the conventional loads that we are using is designed to work in AC current and not DC current. 

As you know the solar radiation is not constant through the day, so that converter is essential element in the PV system regardless the load if it is AC or DC. To make sure that the load (AC, DC or battery) receive stable voltage.

Put a diode in between solar panel and battery..then u can directly charge the battery from solar panel.