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EP-3513449-B1 - FLEXIBLE BATTERY

EP3513449B1EP 3513449 B1EP3513449 B1EP 3513449B1EP-3513449-B1

Inventors

  • MILES, ANTHONY
  • VYAS, Niladri
  • MASHEDER, Ben
  • HUGHES, STEVEN

Dates

Publication Date
20260506
Application Date
20170913

Claims (15)

  1. A method of fabricating a flexible battery, the method comprising: a. forming a first substrate (102) on a first release liner (101) and a second substrate (102) on a second release liner (101); b. forming at least one current collector layer (103) on each of the first and second substrates (102); c. forming an anode side (109) of the flexible battery by forming an anode (104) on the current collector layer (103) of the first substrate (102); d. forming a cathode side (110) of the flexible battery by forming a cathode (107) on the current collector layer (103) of the second substrate (102); e. depositing an electrolyte (105) on both the anode (104) and cathode (107) or one or all of the anode (104), the cathode (107) and, if used, a separator for placing between the anode (104) and cathode (107); f. adhering and sealing the anode side (109) and the cathode side (110) together such that the anode (104) and cathode (107) face one another with the electrolyte (105) in between, leaving electrode terminals exposed for connection; and g. removing the flexible battery from the release liners (101).
  2. The method of claim 1, wherein the first and second substrates (102) are formed by printing substrate material onto the first release liner (101) and the second release liner (101) respectively.
  3. The method of claim 2, wherein the printed substrate material is a film forming polymer.
  4. The method of any one of claims 2 or 3, wherein the printed substrate material is cured following printing.
  5. The method of any preceding claim, wherein the current collector layers (103) are formed by printing current collector ink on the first substrate (102) and second substrate (102).
  6. The method of any preceding claim, wherein the current collector layers (103) are made from carbon-based materials.
  7. The method of any preceding claim, wherein the current collector layers (103) are made from at least one of metal particles, mixtures of metallic and non-metallic particles, or particles of metal alloys.
  8. The method of any one of claims 5 to 7, wherein the printed current collector ink is cured or dried to form the current collector layers (103).
  9. The method of any preceding claim, wherein the anode (104) and cathode (107) are formed by printing.
  10. The method of any preceding claim, wherein the cathode (107) contains at least one material of group comprising α-MnO 2 , λ-MnO 2 , TiO 2 , todorokite, zinc-hexacyanoferrate, copper-hexacyanoferrate, spinel-Mn 2 O 4 , nickel-hexacyanoferrate, at least one carbon nanotubes layer, at least one graphite layer, or at least one graphene layer.
  11. The method of any one of claims 9 or 10, wherein the printed anode (104) and cathode inks (107) are cured.
  12. The method of any preceding claim, wherein the electrolyte (105) is deposited by printing.
  13. The method of any preceding claim, wherein prior to adhering the anode side (109) and cathode side (110) of the flexible battery, the separator is placed between the anode (104) and cathode (107).
  14. The method of claim 13, wherein the separator is a thin, semipermeable membrane.
  15. The method of any one of claims 13 or 14, wherein prior to placing the separator between the anode (104) and cathode (107), the separator is coated in electrolyte (105).

Description

Field of the Invention This invention relates to a flexible battery and a method of manufacturing the same. Background of the Invention A battery is capable of producing electricity through electrochemical reactions between its two electrodes (anode and cathode) in the presence of an electrolyte. Batteries are typically divided into two categories, depending on the nature of the electrochemical reaction taking place within them. Batteries with irreversible chemical reactions are termed as 'primary' and batteries with reversible chemical reactions are termed as 'secondary'; such batteries are also known as 'non-rechargeable' and 'rechargeable' respectively. Non-rechargeable batteries based on Zn-MnO2 (alkaline) chemistry are most commonly used in small electronic objects such as toys, remote controls, flashlights etc., whereas rechargeable batteries are commonly based on Li-ion chemistry and used in high end items such as laptops, cellular phones, tablet computers etc. Both non-rechargeable and rechargeable batteries mainly come in cylindrical or cuboid shapes which are not customisable for different applications; this restricts introduction of novel design concepts in the field of electronic product development. There is a need for energy storage devices that do not have the size, weight and form of traditional batteries. Many applications require their batteries to be lightweight, flexible, and as thin as possible so as not to affect the form of the product and/or to fit inside the cavity of a product. The majority of rechargeable and non-rechargeable thin batteries that are currently available on the market are based on Zn-MnO2 (alkaline) and lithium-ion chemistries respectively. These chemistries tend to be used as they comprise inexpensive and recyclable materials and inks containing the active ingredients for forming the active layers only require low temperature curing processes. However, certain components such as electrolytes and some raw materials used in lithium based batteries are flammable and toxic, rendering them hazardous for certain applications. Additionally current collectors for printed lithium based batteries require a high temperature sintering process, which is unfavourable in some cases. Commercially available thin batteries are somewhat flexible but their capacity and voltage decrease when repeatedly flexed. These batteries are mainly used in radiofrequency identification (RFID) tags, smart cards and temperature sensing strips, but are not appropriate for integration in larger energy storage devices or high power consumption related applications. Furthermore, these batteries do not meet the requirements of a fully formable, scalable, flexible battery for large and small applications. One reason why these batteries are unsuitable for this application is their construction, which uses metal foils and plastic substrates to form the electrodes and the packaging. Using printed materials, including printed packaging, electrodes and electrolyte, a battery with the kind of unidirectional flexibility, lightweight body, and scalable production, which can be produced in both small and large design can be achieved. US 2006/0115717 A1 describes a method for printing flexible batteries; both the electrodes are printed but the substrates used for printing those electrodes are based on plastic which leads to a semi-flexible battery. US 2008/0063931 A1 describes printed batteries manufactured in a layered fashion on paper and polyester film substrates; the cells are based on Zn-MnO2 chemistry but fail to display the characteristic voltage of 1.5 V. US 2005/0260492 A1 describes a printed battery with Zn-foil anode and a printed MnO2 cathode; batteries developed in this manner are not fully printable as one of the electrodes is based on metal foil. US 8574742 B2 describes printed batteries based on Zn-MnO2 chemistry using anode and cathode inks deposited onto non-conductive flexible plastic substrates; the inks for depositing electrode materials are mixed with a commercially available carbon paste in order to increase their electrical conductivity and current collection efficiency. It is reported in this publication that the majority of printed electrodes with high electrical conductivity either broke or became electrically resistive upon flexing. It is evident from the prior art that the efforts for making a highly flexible printed battery have been unsuccessful so far as no disclosure offers a fully printable battery comprising all of the layers printed on top of each other, whilst being highly flexible, and with a performance comparable to standard primary or secondary batteries. US 2012/058378 A1 discloses a method of manufacturing a flexible film battery including anode and cathode structures. WO 2010/149850 A1 discloses a method of producing thin batteries using anode and cathode webs comprising anode and cathode half cells consisting of multiple materials layered on top of each other. Statements