EXHIBIT 99.1

NEWS RELEASE

For Immediate Release May 10, 2004 Contact: Michael Sund (858) 503-3233

MAXWELL TECHNOLOGIES REPORTS Q1 ‘04 FINANCIAL RESULTS; HIGHER

MARGINS, INCREASED PRODUCTIVITY, LOWER EXPENSES DRIVE IMPROVING

PERFORMANCE

SAN DIEGO, Calif.—Maxwell Technologies, Inc. (Nasdaq: MXWL) today reported a net loss of $585,000, or $0.04 per share, on revenue of $10.5 million for its first quarter ended March 31, 2004. That compares with a net loss of $4.4 million, or $0.32 per share, on revenue of $10.2 million for the same period in 2003. Cash and short-term investments totaled $10.9 million as of March 31, 2004.

Dr. Richard Balanson, Maxwell’s president and chief executive officer, said that the company’s improving financial performance is being driven by higher margins, dramatically increased productivity and lower operating expenses.

“As we stated at the beginning of the year, the steps we took in the second half of 2003 to focus exclusively on our high-margin core products, phase out or divest low-margin products, improve productivity and reduce expenses have positioned the company for growth and a return to profitability by the end of 2004,” Balanson said. “In line with our projections in January, the company’s quarterly breakeven revenue threshold was less than $12 million for the first quarter, as compared with more than $17 million in the first quarter of 2003. We expect that threshold to continue to fall in future quarters as margins continue to increase.”

Balanson said that gross margins on first quarter product sales were 25 percent, as compared with 13 percent for the corresponding quarter in 2003, reflecting an increasingly favorable revenue mix. He said that first quarter ultracapacitor revenue totaled $2.5 million, including the final $1 million installment of a $5 million license payment from Yeong-Long Technologies Co., Ltd., for the right to manufacture and market Maxwell’s proprietary BOOSTCAP^® ultracapacitor products in China.

“Ultracapacitor unit sales reached an all-time high in Q1, but product revenue was up only marginally from Q4 because three customer product launches were delayed, and most of the volume we had was in our lowest priced small cells,” Balanson noted. “With unit sales continuing to grow and mix shifting toward higher-priced products, we are expecting ultracapacitors to achieve a 20 to 25 percent compound quarter-to-quarter revenue growth rate for the year.”

Management will conduct a conference call and simultaneous webcast to discuss first quarter financial results and the outlook for the balance of 2004, and answer analysts’ questions at 11 a.m. (eastern) tomorrow, Tuesday, May 11, 2004. The call may be accessed by dialing toll-free, (800) 362-0571 from the U.S. and Canada, or (785) 832-1508 for international callers. The webcast and subsequent replay may be accessed at the company’s web site via the following link: http://www.maxwell.com/investors/presentations.html.

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Maxwell is a leading developer and manufacturer of innovative, cost-effective energy storage and power delivery solutions. Our BOOSTCAP^® ultracapacitor cells and multi-cell modules and POWERCACHE^® backup power systems provide safe and reliable power solutions for applications in consumer and industrial electronics, transportation and telecommunications. Our CONDIS^® high-voltage grading and coupling capacitors help to ensure the safety and reliability of electric utility infrastructure and other applications involving transport, distribution and measurement of high-voltage electrical energy. Our radiation-mitigated microelectronic products include power modules, memory modules and single board computers that incorporate powerful commercial silicon for superior performance and high reliability in aerospace applications. For more information, please visit our website: www.maxwell.com.

This news release contains forward-looking statements that are subject to risks and uncertainties. These include development and acceptance of products based on new technologies, demand for original equipment manufacturers’ products reaching anticipated levels, general economic conditions in the markets served by the company’s products, cost-effective manufacturing of new products, the impact of competitive products and pricing and risks and uncertainties involved in foreign operations. These and other risks are detailed from time-to-time in the Company’s SEC reports, including the report on Form 10-K for the fiscal year ended December 31, 2003. Actual results may differ materially from those projected. These forward-looking statements represent the Company’s judgment as of the date of this news release. The Company disclaims any intent or obligation to update these forward-looking statements.

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MAXWELL TECHNOLOGIES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share information)

	Three Months Ended March 31,
	2004			2003
Net revenue:
Product sales	$	9,465		$	10,241
License fees		1,000			—
Net revenue		10,465			10,241
Cost of sales		7,067			8,930
Gross profit		3,398			1,311
Operating expenses (income):
Selling, general and administrative		2,792			4,073
Research and development		1,218			1,307
Other income, net		—			(14	)
Gain on sale of asset		(7	)		—
Gain on sale of business.		—			(228	)
Interest income, net		(50	)		(27	)
Total operating expenses		3,953			5,111
Loss from continuing operations before income taxes		(555	)		(3,800	)
Income tax benefit.		—			(14	)
Loss from continuing operations		(555	)		(3,786	)
Discontinued operations, net of taxes:
Loss from operations		(30	)		(575	)
Net loss	$	(585	)	$	(4,361	)
Basic and diluted net loss per share:
Loss from continuing operations	$	(0.04	)	$	(0.28	)
Loss from discontinued operations		—			(0.04	)
Net loss per share	$	(0.04	)	$	(0.32	)
Shares used in computing:
Basic and diluted net loss per share		14,386			13,741

MAXWELL TECHNOLOGIES, INC. AND SUBSIDIARIES

UNAUDITED SEGMENT INFORMATION

(in thousands)

	Three Months Ended March 31,
	2004			2003
Revenue:
Maxwell High Reliability	$	9,873		$	7,833
I-Bus Computing Systems		—			—
Winding Equipment		592			2,408
Consolidated total	$	10,465		$	10,241
Income (loss):
Maxwell High Reliability		(226	)		(2,766	)
I-Bus Computing Systems		—			(114	)
Winding Equipment		420			(265	)
Total segment operating loss		194			(3,145	)
Corporate expenses		818			943
Gain on sale of businesses		—			(228	)
Interest and other income, net		(69	)		(60	)
Loss from continuing operations before income taxes	$	(555	)	$	(3,800	)

MAXWELL TECHNOLOGIES, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(in thousands, except per share information)

	March 31, 2004			December 31, 2003
	(unaudited)
ASSETS
Current assets:
Cash and cash equivalents	$	8,483		$	9,784
Short-term investments		2,431			2,455
Trade and other accounts receivable, net		6,863			5,936
Inventories		7,289			7,309
Prepaid expenses and other current assets		1,095			1,143
Total current assets		26,161			26,627
Property, plant and equipment, net		10,366			10,769
Other intangible assets, net		1,917			2,002
Goodwill		18,968			19,478
Prepaid pension asset		3,962			3,962
Other non-current assets		—			175
	$	61,374		$	63,013
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable and accrued liabilities	$	6,686		$	7,650
Accrued warranty		1,359			1,262
Customer deposits		433			599
Accrued employee compensation		1,748			1,653
Short-term borrowings and current portion of long-term debt		1,716			1,851
Deferred tax liability		336			339
Net liabilities of discontinued operations		1,375			1,494
Total current liabilities		13,653			14,848
Deferred tax liability		473			473
Long-term debt, excluding current portion		179			—
Stockholders’ equity:
Common stock, $0.10 par value per share, 40,000 shares authorized; 14,440 and 14,339 shares issued and outstanding at March 31, 2004 and December 31, 2003, respectively		1,444			1,434
Additional paid-in capital		113,998			113,221
Accumulated deficit		(70,895	)		(70,310	)
Accumulated other comprehensive income		2,522			3,347
Total stockholders’ equity		47,069			47,692
	$	61,374		$	63,013

MAXWELL TECHNOLOGIES, INC. AND SUBSIDIARIES

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

	Three Months Ended March 31,
	2004			2003
Cash flows from operating activities:
Loss from continuing operations	$	(555	)	$	(3,786	)
Adjustments to reconcile loss from continuing operations to net cash provided by (used in) operating activities:
Depreciation and amortization		872			877
Gain on sales of property and equipment		(7	)		—
Gain on sales of business		—			(228	)
Provision for losses on accounts receivable		36			292
Changes in operating assets and liabilities:
Trade and other accounts receivable		(966	)		1,864
Inventories		(64	)		300
Prepaid expenses and other current assets		223			(83	)
Deferred income taxes		(3	)		6
Accounts payable and accrued liabilities		(867	)		(3,475	)
Customer deposits		(166	)		3,137
Accrued employee compensation		95			317
Net cash used in operating activities		(1,402	)		(779	)
Cash flows from investing activities:
Proceeds from sale of business		—			278
Acquisition of property, plant and equipment		(544	)		(397	)
Proceeds from sale of property and equipment		17			—
Proceeds from sale of short-term investments		176			2,836
Purchases of short-term investments		(151	)		(924	)
Net cash provided by (used in) investing activities		(502	)		1,793
Cash flows from financing activities:
Principal payments on long-term debt and short-term borrowings		(872	)		(75	)
Proceeds from long-term and short-term borrowings		972			314
Proceeds from exercise of stock options		787			121
Net cash provided by financing activities		887			360
Increase (decrease) in cash and cash equivalents from continuing operations		(1,017	)		1,374
Net cash used in discontinued operations		(149	)		(328	)
Effect of exchange rate changes on cash and cash equivalents		(135	)		28
Increase (decrease) in cash and cash equivalents		(1,301	)		1,074
Cash and cash equivalents, beginning of period		9,784			3,545
Cash and cash equivalents, end of period	$	8,483		$	4,619
Supplemental disclosures of cash flow information:
Cash paid for interest	$	8		$	4
Cash paid for income taxes	$	—		$	—