Exhibit 3.1

SECOND AMENDED AND RESTATED
CERTIFICATE OF INCORPORATION
OF
TORTOISE ACQUISITION CORP.

Vincent T. Cubbage hereby certifies that:

ONE: The name of this company is Tortoise Acquisition Corp. and the date of filing the original Certificate of Incorporation of this corporation with the Secretary of State of Delaware was November 7, 2018.

TWO: Vincent T. Cubbage is the duly elected and acting Chief Executive Officer of Tortoise Acquisition Corp., a Delaware corporation.

THREE: The Amended and Restated Certificate of Incorporation of this corporation is hereby amended and restated to read as follows:

I.

The name of this corporation is Hyliion Holdings Corp. (the “Company”).

II.

The address of the Company’s registered office in the State of Delaware is Corporation Service Company, 251 Little Falls Drive, in the City of Wilmington, County of New Castle, Delaware 19808. The name of its registered agent at such address is Corporation Service Company.

III.

The purpose of the Company is to engage in any lawful act or activity for which a corporation may be organized under the Delaware General Corporation Law (“DGCL”).

IV.

A. The Company is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares which the Company is authorized to issue is 260,000,000 shares. 250,000,000 shares shall be Common Stock, each having a par value of one-hundredth of one cent ($0.0001). 10,000,000 shares shall be Preferred Stock, each having a par value of one-hundredth of one cent ($0.0001).

B. Effective immediately upon the filing and effectiveness of this Second Amended and Restated Certificate of Incorporation with the Office of the Secretary of State of the State of Delaware (the “Effective Time”), each one share of the Company’s Class A Common Stock, par value $0.0001 per share (the “Class A Common Stock”), that was issued and outstanding immediately prior to the Effective Time shall automatically be reclassified, redesignated and changed into (a) one validly issued, fully paid and non-assessable share of Common Stock of the Company, par value $0.0001 per share (the “Common Stock”), without any further action by the Company or any stockholder thereof. Each certificate that immediately prior to the Effective Time represented shares of Class A Common Stock (each, a “Prior Certificate”) shall, until surrendered to the Company in exchange for a certificate representing the same number of shares of Common Stock, automatically represent that number of shares of Common Stock into which the shares of Class A Common Stock represented by the Prior Certificate shall have been reclassified and redesignated.

C. The Preferred Stock may be issued from time to time in one or more series. The Board of Directors of the Company (the “Board of Directors”) is hereby expressly authorized to provide for the issue of all or any number of the shares of the Preferred Stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in the resolution or resolutions adopted by the Board of Directors providing for the issuance of such shares and as may be permitted by the DGCL. The Board of Directors is also expressly authorized to increase or decrease the number of shares of any series subsequent to the issuance of shares of that series, but not below the number of shares of such series then outstanding. In case the number of shares of any series shall be decreased in accordance with the foregoing sentence, the shares constituting such decrease shall resume the status that they had prior to the adoption of the resolution originally fixing the number of shares of such series. The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the voting power of the stock of the Company entitled to vote thereon, without a separate vote of the holders of the Preferred Stock, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any certificate of designation filed with respect to any series of Preferred Stock.

D. Each outstanding share of Common Stock shall entitle the holder thereof to one vote on each matter properly submitted to the stockholders of the Company for their vote; provided, however, that, except as otherwise required by law, holders of Common Stock shall not be entitled to vote on any amendment to this Second Amended and Restated Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock) that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together as a class with the holders of one or more other such series, to vote thereon by law or pursuant to this Second Amended and Restated Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock).

V.

For the management of the business and for the conduct of the affairs of the Company, and in further definition, limitation and regulation of the powers of the Company, of its directors and of its stockholders or any class thereof, as the case may be, it is further provided that:

A.

1. The management of the business and the conduct of the affairs of the Company shall be vested in the Board of Directors. The number of directors which shall constitute the Board of Directors shall be fixed exclusively by resolutions adopted by a majority of the authorized number of directors constituting the Board of Directors.

2. BOARD OF DIRECTORS

Subject to the rights of the holders of any series of Preferred Stock to elect additional directors under specified circumstances, the Board of Directors shall be divided into three classes, as nearly equal in number as possible and designated Class I, Class II and Class III. The Board of Directors is authorized to assign members of the Board of Directors already in office to Class I, Class II or Class III. The term of the initial Class I Directors shall expire at the first annual meeting of the stockholders of the Company following the effectiveness of this Amended and Restated Certificate; the term of the initial Class II Directors shall expire at the second annual meeting of the stockholders of the Company following the effectiveness of this Second Amended and Restated Certificate; and the term of the initial Class III Directors shall expire at the third annual meeting of the stockholders of the Company following the effectiveness of this Second Amended and Restated Certificate. At each succeeding annual meeting of the stockholders of the Company, beginning with the first annual meeting of the stockholders of the Company following the effectiveness of this Second Amended and Restated Certificate, successors to the class of directors whose term expires at that annual meeting shall be elected for a three-year term or until the election and qualification of their respective successors in office, subject to their earlier death, resignation or removal. Subject to the rights of the holders of any series of Preferred Stock to elect additional directors under specified circumstances, if the number of directors is changed, any increase or decrease shall be apportioned by the Board among the classes so as to maintain the number of directors in each class as nearly equal as possible, but in no case shall a decrease in the number of directors shorten the term of any incumbent director.

Notwithstanding the foregoing provisions of this section, each director shall serve until his successor is duly elected and qualified or until his earlier death, resignation or removal. No decrease in the number of directors constituting the Board of Directors shall shorten the term of any incumbent director.

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3. REMOVAL OF DIRECTORS. Subject to any limitations imposed by applicable law, any individual director or directors may be removed with cause by the affirmative vote of the holders of at least 66 2/3% of the voting power of all then-outstanding shares of capital stock of the Company entitled to vote generally at an election of directors.

4. VACANCIES. Subject to any limitations imposed by applicable law and subject to the rights of the holders of any series of Preferred Stock, any vacancies on the Board of Directors resulting from death, resignation, disqualification, removal or other causes and any newly created directorships resulting from any increase in the number of directors, shall, unless the Board of Directors determines by resolution that any such vacancies or newly created directorships shall be filled by the stockholders and except as otherwise provided by applicable law, be filled only by the affirmative vote of a majority of the directors then in office, even though less than a quorum of the Board of Directors, and not by the stockholders. Any director elected in accordance with the preceding sentence shall hold office for the remainder of the full term of the director for which the vacancy was created or occurred and until such director’s successor shall have been elected and qualified.

B.

1. BYLAW AMENDMENTS. The Board of Directors is expressly empowered to adopt, amend or repeal the Bylaws of the Company. Any adoption, amendment or repeal of the Bylaws of the Company by the Board of Directors shall require the approval of a majority of the authorized number of directors. The stockholders shall also have power to adopt, amend or repeal the Bylaws of the Company; provided, however, that, in addition to any vote of the holders of any class or series of stock of the Company required by law or by this Second Amended and Restated Certificate of Incorporation, such action by stockholders shall require the affirmative vote of the holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of the capital stock of the Company entitled to vote generally in the election of directors, voting together as a single class.

2. The directors of the Company need not be elected by written ballot unless the Bylaws so provide.

3. No action shall be taken by the stockholders of the Company except at an annual or special meeting of stockholders called in accordance with the Bylaws, and no action shall be taken by the stockholders by written consent or electronic transmission.

4. Advance notice of stockholder nominations for the election of directors and of business to be brought by stockholders before any meeting of the stockholders of the Company shall be given in the manner provided in the Bylaws of the Company.

VI.

A. The liability of the directors for monetary damages shall be eliminated to the fullest extent permitted by applicable law.

B. To the fullest extent permitted by applicable law, the Company is authorized to provide indemnification of (and advancement of expenses to) directors, officers and agents of the Company (and any other persons to which applicable law permits the Company to provide indemnification) through Bylaw provisions, agreements with such agents or other persons, vote of stockholders or disinterested directors or otherwise in excess of the indemnification and advancement otherwise permitted by such applicable law. If applicable law is amended after approval by the stockholders of this Article VI to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of a director to the Company shall be eliminated or limited to the fullest extent permitted by applicable law as so amended.

C. Any repeal or modification of this Article VI shall only be prospective and shall not affect the rights or protections or increase the liability of any director under this Article VI in effect at the time of the alleged occurrence of any act or omission to act giving rise to liability or indemnification.

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VII.

A. Unless the Company consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall (or, if and only if the Court of Chancery of the State of Delaware lacks subject matter jurisdiction, any state court located within the State of Delaware or, if and only if all such state courts lack subject matter jurisdiction, the federal district court for the District of Delaware), to the fullest extent permitted by applicable law, be the sole and exclusive forum for the following types of actions or proceedings under Delaware statutory or common law: (A) any derivative action or proceeding brought on behalf of the Company; (B) any action or proceeding (including any class action) asserting a claim of breach of a fiduciary duty owed by any current or former director, officer or other employee of the Company to the Company or the Company’s stockholders; (C) any action or proceeding (including any class action) asserting a claim against the Company or any current or former director, officer or other employee of the Company arising out of or pursuant to any provision of the DGCL, this Second Amended and Restated Certificate of Incorporation or the Bylaws of the Company (as each may be amended from time to time); (D) any action or proceeding (including any class action) to interpret, apply, enforce or determine the validity of this Second Amended and Restated Certificate of Incorporation or the Bylaws of the Company (including any right, obligation or remedy thereunder); (E) any action or proceeding as to which the DGCL confers jurisdiction to the Court of Chancery of the State of Delaware; or (F) any action asserting a claim against the Company or any director, officer or other employee of the Company governed by the internal affairs doctrine, in all cases to the fullest extent permitted by law and subject to the court’s having personal jurisdiction over the indispensable parties named as defendants. This Article VII shall not apply to suits brought to enforce a duty or liability created by the Securities Exchange Act of 1934, as amended, or any other claim for which the federal courts have exclusive jurisdiction.

B. Unless the Company consents in writing to the selection of an alternative forum, the federal district courts of the United States of America shall be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act of 1933, as amended.

C. Any person or entity purchasing, holding, owning or otherwise acquiring any interest in any security of the Company shall be deemed to have notice of and to have consented to the provisions of this Article VII.

VIII.

A. The Company reserves the right to amend, alter, change or repeal any provision contained in this Second Amended and Restated Certificate of Incorporation, in the manner now or hereafter prescribed by statute, except as provided in paragraph B. of this Article VIII, and all rights conferred upon the stockholders herein are granted subject to this reservation.

B. Notwithstanding any other provisions of this Second Amended and Restated Certificate of Incorporation or any provision of law which might otherwise permit a lesser vote or no vote, but in addition to any affirmative vote of the holders of any particular class or series of the Company required by law or by this Second Amended and Restated Certificate of Incorporation or any certificate of designation filed with respect to a series of Preferred Stock, the affirmative vote of the holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of capital stock of the Company entitled to vote generally in the election of directors, voting together as a single class, shall be required to alter, amend or repeal Articles V, VI, VII and VIII.

* * * *

FOUR: This Second Amended and Restated Certificate of Incorporation has been duly approved by the Board of Directors of the Company.

FIVE: This Second Amended and Restated Certificate of Incorporation was approved by the holders of the requisite number of shares of the Company. This Second Amended and Restated Certificate of Incorporation has been duly adopted in accordance with the provisions of Sections 242 and 245 of the DGCL by the stockholders of the Company.

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IN WITNESS WHEREOF, the undersigned has caused this Second Amended and Restated Certificate of Incorporation to be signed on this 1^st day of October, 2020.

TORTOISE ACQUISITION CORP.

/s/ Vincent T. Cubbage

Vincent T. Cubbage

Chief Executive Officer

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