List of Electronic Components and Modules products
- classification：Electronic Components and Modules
91～135 item / All 61705 items
It won't break even after 1 million repetitions! A mat switch with reliable operation, high durability, and low price. Suitable for options in machine tools as well. Please consult us about delivery t...
- Sensors
We can accommodate high resistance over 10,000 ohms, with diameters ranging from approximately 30 mm to 8 inches, and we also offer thinning and chip processing arrangements!
- Other semiconductors
- Processing Contract
- Wafer
Custom-made transformers ideal for imported equipment from overseas: Industrial Equipment Edition
- Transformers
- transformer
- Inductor Coil
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
[Coverage] Results of the exhibition! Collected 447 surveys over the 3-day event at one booth! (Nikko Electric Co., Ltd., Custom Transformer Manufacturer)
- Exhibition planning/construction
- Transformers
- Inductor Coil
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
[Video] Introducing Nichiko Electric's company, products, and factory in a video (Custom Transformer Manufacturer Nichiko Electric Co., Ltd.)
- Transformers
- transformer
- Inductor Coil
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
【Orders from 9/1 to 30】3% OFF on various JST (Japan Solderless Terminal Manufacturing Co., Ltd.) crimp terminals from the regular price! Quotes are welcome even if you don't place an order.
- Crimp Terminal
- Terminal Blocks
- Connector Terminal Block
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
From January 5, 2026! New Year Big Sale at Nichiko Electric Sendai Sales Office. 3% OFF campaign on various products from JST (Japan Solderless Terminal Manufacturing Co., Ltd.) regular prices.
- Crimp Terminal
- Connector Terminal Block
- Terminal Blocks
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
[Until the 15th] Nichiko Electric Sendai Sales Office New Year Big Sale All products from Japan Solderless Terminal Manufacturing (JST) are currently on a 3% OFF campaign.
- Crimp Terminal
- Terminal Blocks
- Switchboard
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
The shape can be discussed separately! Introducing the manufacturing range of single-phase transformers, three-phase transformers, and reactors.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
Custom-made transformers and reactors contributing to high-precision control.
- transformer
Supporting high power supply! Introducing the manufacturing range of single-phase and three-phase transformers and reactors.
- transformer
The shape can be discussed separately! A transformer-reactor that contributes to energy conservation.
- transformer
The shape can be discussed separately! Introducing the manufacturing range of single-phase and three-phase transformers and reactors.
- transformer
Exhibiting at the "New Manufacturing and New Services Exhibition for Small and Medium Enterprises"! NCW3000 (3000VA) is also under development! Can be installed in narrow spaces.
- transformer
TECHNO-FRONTIER 2023, the 38th Power System Exhibition (July 26-28, 2023, at Tokyo Big Sight), will be held. We will be exhibiting at booth number 3C-04, custom transformer manufacturer Nikko Electric Co., Ltd.!
We are pleased to announce that our company will be exhibiting at "TECHNO-FRONTIER 2023, the 38th Power System Exhibition," which will be held at Tokyo Big Sight, East Exhibition Hall, from July 26 (Wednesday) to July 28 (Friday). We kindly invite you to visit our booth during this event, and we look forward to seeing you there despite your busy schedule. Exhibition: "TECHNO-FRONTIER 2023, the 38th Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 26 (Wednesday) to July 28 (Friday), 2023 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, East Exhibition Hall, 3-11-1 Ariake, Koto-ku, Tokyo Booth No.: 3C-04 Nikkodenki Co., Ltd. http://www.nikkodenki.com
As of April 1, 2022, Nikko Electric Co., Ltd.'s headquarters in Watari has switched all its electricity to 100% renewable energy (CO2-free electricity).
- transformer
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
We have prepared a wide variety of shapes to accommodate various designs! Introducing switching transformers.
- transformer
TECHNO-FRONTIER 2023, the 38th Power System Exhibition (July 26-28, 2023, at Tokyo Big Sight), will be held. We will be exhibiting at booth number 3C-04, custom transformer manufacturer Nikko Electric Co., Ltd.!
We are pleased to announce that our company will be exhibiting at "TECHNO-FRONTIER 2023, the 38th Power System Exhibition," which will be held at Tokyo Big Sight, East Exhibition Hall, from July 26 (Wednesday) to July 28 (Friday). We kindly invite you to visit our booth during this event, and we look forward to seeing you there despite your busy schedule. Exhibition: "TECHNO-FRONTIER 2023, the 38th Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 26 (Wednesday) to July 28 (Friday), 2023 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, East Exhibition Hall, 3-11-1 Ariake, Koto-ku, Tokyo Booth No.: 3C-04 Nikkodenki Co., Ltd. http://www.nikkodenki.com
[Coverage] Examples of Utilizing Exhibitions! Experience with Winding and Friends on SNS, Appearance of NIKKO-chan (Custom Transformer Manufacturer NIKKO Electric Co., Ltd.)
- Exhibition planning/construction
- Transformers
- transformer
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
Until orders received by 5/31, all types of crimp terminals manufactured by JST (Japan Solderless Terminal Manufacturing Co., Ltd.) are available at a 3% discount off the regular price! We welcome inq...
- Crimp Terminal
- Terminal Blocks
- Connector Terminal Block
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
Amorphous Dry Transformer by Nikkodenki, a transformer for the decarbonization era! Reducing power costs! Reducing greenhouse gas emissions!
- Transformers
- transformer
- UPS/Uninterruptible Power Supply
We will be exhibiting at the 'Oosaki Industrial Fair 2025 (October 17th (Friday) and 18th (Saturday) at Takakatsu Arena Oosaki)' at the Nikkou Electric Sendai Sales Office booth!
The "Osaki Industrial Fair 2025" will be held on October 17 (Friday) and 18 (Saturday), 2025, at Takakatsu Arena Osaki in Osaki City, Miyagi Prefecture, where the Nikkou Electric Sendai Sales Office will exhibit. Nikkou Electric Sendai Sales Office operates as a "specialist group in snow melting," proposing and installing snow melting equipment throughout the Tohoku region. We also handle repairs and maintenance of electric motors, as well as electrical materials (such as crimp terminals and circuit breakers). Our company is strongly associated with "Transformers Nikkou Electric," so please take this opportunity to visit our booth at the "Osaki Industrial Fair 2025." ◎ Osaki Industrial Fair 2025 https://osaki-industries.com/ Date: October 17 (Friday) and 18 (Saturday), 2025, from 10:00 to 16:00 Venue: Takakatsu Arena Osaki (Osaki City Furukawa General Gymnasium) 4-5-2 Asahi, Furukawa, Osaki City, Miyagi Prefecture Admission: Free Organizer: General Incorporated Association Osaki Industrial Promotion Organization, Osaki City
It's still okay is the most dangerous.
- transformer
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
- power supply
Introduction of energy-saving, lightweight, high-efficiency transformers.
- transformer
We will exhibit at TECHNO FRONTIER 2026, the 41st Power System Exhibition at Tokyo Big Sight!
We are pleased to announce that our company will be exhibiting at the "TECHNO FRONTIER 2026 41st Power System Exhibition," which will be held at Tokyo Big Sight from July 15 (Wednesday) to July 17 (Friday). We understand that you may be busy, but we sincerely hope you will take this opportunity to visit our booth. Exhibition: "TECHNO FRONTIER 2026 41st Power System Exhibition" (https://www.jma.or.jp/tf/) Date: July 15 (Wednesday) to July 17 (Friday), 2026 Time: 10:00 AM to 5:00 PM Location: Tokyo Big Sight, West Exhibition Hall Booth No.: West Hall 1 [1-W26]
Adaptable to harsh environments! The shape and specifications can be discussed separately for the transformer-reactor.
- transformer
Now, air becomes an asset. Gently circulate the air throughout the entire space to improve air conditioning efficiency.
- fan
- air conditioning
![[Free Catalog] Energy-saving Large ...](https://image.mono.ipros.com/public/product/image/2117067/IPROS6012063754041049386.png?w=280&h=280){kind=small}
We offer nine different models in various sizes, providing the right solution!
- fan
- air conditioning
Designed with a compact and lightweight structure to reduce the burden on installation, focusing on efficiency and reliability!
- fan
- air conditioning
15-40% improvement compared to general products of the same size! Achieves comfortable air circulation without unevenness.
- fan
- air conditioning
![[Nationwide Service] Installation o...](https://image.mono.ipros.com/public/product/image/2117067/IPROS5549599585519665701.png?w=280&h=280){kind=small}
From urban areas to rural sites, quickly and reliably! We will assist you in creating a safe environment.
- fan
- air conditioning
MSolutions 4x1 LAN Switcher
- Web/Video Conference
- LAN construction and wiring work
- Other electronic parts
Aren't the battery costs of AGVs a significant barrier to reducing equipment maintenance costs?
- Secondary Cells/Batteries
- Cells and batteries
![[Manufacturer Discontinued Product]...](https://image.mono.ipros.com/public/product/image/2117112/IPROS16887709436720517366.jpg?w=280&h=280){kind=small}
Aren't you giving up on "out of stock" and "discontinued"?
- Secondary Cells/Batteries
- Cells and batteries
Your charger can be used as is and is compatible with lithium battery replacement.
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
【Industrial Batteries】【Power that rivals engines】High-output lithium batteries accelerating the electrification of construction and agricultural machinery.
- Lithium-ion battery
Non-contact charging compatible lithium battery system for AGV/AMR.
- Lithium-ion battery
Would you like to replace your lithium battery without changing your charger?
- Lithium-ion battery
"Switching from other brands" with equal or better performance at a superior cost performance.
- Lithium-ion battery
Would you like to replace your lithium battery without changing your charger?
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
Would you like to replace your lithium battery without changing your charger?
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
Replacing lead with shorter charging times and longer lifespan to maximize AGV operational efficiency.
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
Would you like to replace your lithium battery without changing your charger?
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
Dedicated lithium battery designed for AGV and AMR.
- Lithium-ion battery
- Secondary Cells/Batteries
- Cells and batteries
[Industrial Battery] Equipped with a specially designed BMS optimized for wireless power transfer. This single unit enables non-contact and lithium conversion for existing AGVs.
- Lithium-ion battery