Exhibit 99.1
IRREVOCABLE PROXY AND POWER OF ATTORNEY
This IRREVOCABLE PROXY AND POWER OF ATTORNEY (this Proxy Agreement) is entered into as of September 30, 2021,
by and among SB Energy Global Holdings One Ltd. (SoftBank), ACON S2 Acquisition Corp. (the Company), ESS Tech, Inc. (ESS), and the Secretary of the Company (the
Proxyholder). Each of SoftBank, ESS, the Proxyholder and the Company may hereinafter be referred to as a Party and collectively as the Parties. SoftBank and its respective
affiliates are collectively referred to herein as SoftBank. The Proxyholder shall initially be Amir Moftakhar. Capitalized terms not otherwise defined herein shall have the meaning set forth in the Letter Agreement (as
defined below).
WHEREAS, SoftBank, ESS, and the Company are entering into this Proxy Agreement pursuant to the terms and
conditions contemplated by that certain letter agreement by and among SoftBank and ESS, dated as of May 6, 2021 (the Letter Agreement);
WHEREAS, the Company entered into a merger agreement, dated May 6, 2021, with ESS and SCharge Merger Sub, Inc., a Delaware
corporation and wholly-owned subsidiary of the Company (Merger Sub), pursuant to which Merger Sub will merge with and into ESS, with ESS surviving the merger and becoming a wholly-owned direct subsidiary of the Company (the
Merger), and each outstanding share of ESS will be converted into and exchanged for shares of the surviving corporation of the Merger (New ESS);
WHEREAS, SoftBank is currently the holder of certain shares of capital stock of ESS, and pursuant to, and at the closing of the Merger
Transaction and the transactions contemplated thereby (the Closing), SoftBank will receive shares of New ESS in exchange for its shares of ESS and acquire additional shares of capital stock of New ESS (all such shares now
or hereafter acquired, and for so long as such shares are held, by SoftBank, collectively, the Shares);
WHEREAS, effective upon and subject to the consummation of the Closing, SoftBank desires to grant to the Proxyholder, and the
Proxyholder desires to accept, a proxy and undertaking in respect of the voting rights of the Shares; and
WHEREAS, the Board of
Directors of ESS (or a duly authorized committee thereof) has approved this Proxy Agreement, the designation of the Secretary of the Company as the Proxyholder and the transactions contemplated hereby.
NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties hereby
agree to and authorize the following terms, which for the avoidance of doubt will only take effect at the Closing subject to the aforementioned approvals.
1. GRANT OF PROXY AND POWER
OF ATTORNEY. Effective upon and subject to the consummation of the Closing, the Parties hereby agree to the following:
(a) SoftBank hereby irrevocably appoints, authorizes and empowers the Proxyholder, with full power of substitution and
resubstitution (subject to SoftBanks approval in each case), as SoftBanks exclusive attorney-in-fact and proxy, on behalf of SoftBank and in its stead, to
vote and otherwise exercise all voting and voting-related rights (to the fullest extent that SoftBank otherwise would be entitled or eligible) with respect to the Subject Shares (as defined below) in any vote, consent, election, waiver or other
action of New ESS stockholders, whether under applicable law, stock exchange regulation, New ESS Amended and Restated Certificate of Incorporation, as may be amended and/or restated from time to time (the
Charter) or New ESS bylaws, as may be amended and/or restated from time to time (including, without limitation, the power to execute and deliver written consents pursuant to Section 228 of the Delaware General
Corporation Law) (each, a Stockholder Vote), in the same manner as if SoftBank was personally acting on any such matter. For purposes of this Proxy Agreement, and with respect to each Stockholder Vote, (x) the
SB Retained Shares shall mean, (A) prior to the CFIUS Approval (as defined in the Letter Agreement), such Shares that represent up to and including 9.9% of the voting power of the issued and outstanding shares of New
ESS entitled
1