When selecting a TVS (Transient Voltage Suppressor) diode for protecting the VBAT line, you should consider the following:

Based on these considerations, a suitable example could be the SMBJ6.0A, which has:

Be sure to verify the diode’s specification sheet to ensure it fits your specific requirements. Let me know if you need more information or guidance!

the battery reaches its maximum at 4.2 volts

In that case, you'll want to select a TVS diode with a reverse standoff voltage ($V_{RWM}$) slightly above 4.2V to ensure it doesn't trigger during normal operation. A common choice for such applications would be a diode with a $V_{RWM}$ of around 5V.

Here's a suitable example:

This diode should provide adequate protection against voltage transients, while keeping the normal operating voltage range of your battery circuit in mind. Make sure to review the diode’s datasheet to verify that it meets your specific application needs. Let me know if you need further assistance!

it would be perfect but I need a more compact package

For a more compact package, you might want to consider the SOD-323 package. It is much smaller and still provides sufficient transient voltage protection for many battery-operated applications.

The ESD5Z5.0T1G provides a high level of ESD protection and is suitable for applications where PCB space is a constraint. Ensure that the clamping voltage and power rating are within acceptable ranges for your application. Always verify the specific requirements of your circuit and consult the datasheet for any additional details.

Let me know if this fits your needs or if you need further suggestions!

but It has only 174 W, we need at lest 600w

If you're looking for a compact TVS diode with at least 600W power dissipation, you might want to look for options in packages like SOD-123 or SMC, which offer a balance between size and power handling capabilities.

Although the SMAJ5.0A is rated for 400W, ensure that your application requirements align with this rating as it is a trade-off between size and power capability.

For a higher power rating, consider the SMC package:

While the SMC package is larger than SMA, it offers a significantly higher power rating. Select the one that best fits your space and power requirements. Let me know if this meets your needs or if you have further constraints!