Method for assembling and activating lithium-ion based reserve batteries

Abstract

A method for assembling a lithium-ion reserve battery. The method including: charging an assembled lithium-ion reserve battery, the assembled lithium-ion battery including electrodes forming a battery cell, electrolyte and a membrane separating the battery cell and the electrolyte, the electrodes being charged into a charged state; disassembling the charged lithium-ion reserve battery; rinsing and drying at least the electrodes of the disassembled lithium-ion reserve battery; and reassembling the lithium-ion reserve battery with the rinsed and dried electrodes in the charged state and without the electrolyte; wherein the reassembling includes hermetically sealing a housing containing the battery cell. A method for activating such lithium-ion battery further includes, subsequent to the reassembly, introducing the electrolyte into the battery cell to activate the lithium-ion battery.

Claims

1. A method for assembling a lithium-ion reserve battery, the method comprising: charging an assembled lithium-ion reserve battery, the assembled lithium-ion battery including electrodes forming a battery cell, electrolyte and a membrane separating the battery cell and the electrolyte, the electrodes being charged into a charged state; disassembling the charged lithium-ion reserve battery; rinsing and drying at least the electrodes of the disassembled lithium-ion reserve battery; and reassembling the lithium-ion reserve battery with the rinsed and dried electrodes in the charged state and without the electrolyte; wherein the reassembling includes hermetically sealing a housing containing the battery cell.

2. The method of claim 1, wherein the charging comprises fully charging the lithium-ion battery.

3. The method of claim 1, wherein: the rinsing and drying does not include rinsing and drying the membrane; and the reassembling comprises reassembling the lithium-ion battery with a new membrane.

4. The method of claim 1, wherein subsequent to the disassembly, storing the electrolyte for a subsequent activation of the lithium-ion battery.

5. The method of claim 4, wherein the storing comprising storing the electrolyte in the hermetically sealed housing.

6. A method for activating a lithium-ion reserve battery, the method comprising: charging an assembled lithium-ion reserve battery, the assembled lithium-ion battery including electrodes forming a battery cell, electrolyte and a membrane separating the battery cell and the electrolyte, the electrodes being charged into a charged state; disassembling the charged lithium-ion reserve battery; rinsing and drying at least the electrodes of the disassembled lithium-ion reserve battery; reassembling the lithium-ion reserve battery with the rinsed and dried electrodes in the charged state and without the electrolyte, wherein the reassembling includes hermetically sealing a housing containing the battery cell; and subsequent to the reassembly, introducing the electrolyte into the battery cell to activate the lithium-ion battery.

7. The method of claim 6, wherein the charging comprises fully charging the lithium-ion battery.

8. The method of claim 6, wherein: the rinsing and drying does not include rinsing and drying the membrane; and the reassembling comprises reassembling the lithium-ion battery with a new membrane.

9. The method of claim 6, wherein subsequent to the disassembly, storing the electrolyte for a subsequent activation of the lithium-ion battery.

10. The method of claim 9, wherein the storing comprising storing the electrolyte in the hermetically sealed housing.

11. The method of claim 10, wherein the introducing comprises heating the electrolyte and forcing the heated electrolyte under pressure into the lithium-ion battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features, aspects, and advantages of the apparatus of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

(2) The FIGURE illustrates the schematic of the basic pyrotechnic activated reserve battery for fast activation and for low-temperature performance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(3) The LIB cells are structured on a pair of solid electrodes with a porous solid separator membrane between them. The porous separator (most commonly made of polyethylene and polypropylene) is filled with a liquid electrolyte, which is lithium salts dissolved in aprotic organic solvents (alkyl carbonates). The role of separator is mainly to prevent an electrical short circuit between the two electrodes. The separator does not provide a sealing effect. That means the liquid electrolyte is present not only in the porous separator but also in any space inside the closed cells.

(4) The basic process of manufacturing a typical Lithium ion battery can be described using the process of assembling a single Lithium ion cell in an engineering development Swagelok cell. Once assembled the cell is then filled with the electrolyte from the top side and the cell is sealed. The assembled battery is then ready to be charged. This process is well known in the art and is used by battery development engineers for testing various battery chemistries and designs.

(5) In the method of fabricating the Lithium ion based reserve battery of the present invention, following the Lithium ion battery assembly and introduction of the battery electrolyte described above, the battery is fully charged. The cell (in this case the Swagelok cell) is then disassembled, the electrodes are rinsed and dried. The electrodes, now at charged state, can be reassembled together with the same or a new membrane (the membrane is not generally costly and difficult to thoroughly clean and dry). The charged Lithium ion battery without its electrolyte can now be stored for a very long time as long as it is packaged in a hermetically sealed housingas is the practice for almost all liquid reserve and thermal reserve batteries.

(6) The liquid electrolyte is stored outside the cell in a sealed compartment as is the common practice and/or known in the art for currently available liquid reserve batteries. The liquid electrolyte is then injected into the charged Lithium ion battery at the time of activation, also using one of the methods well known in the art for activation of currently available liquid reserve batteries. One such method of activation is described below.

(7) Hereinafter, the charged Lithium ion battery cell without its electrolyte together with its electrolyte in a sealed compartment is referred to as Lithium-ion reserve battery.

(8) It is appreciated by those skilled in the art that the performance of Lithium ion batteries significantly degrades at low temperatures and become almost inactive at temperature below 30 to 40 degrees C. For this reason, it is highly desirable to make the disclosed Lithium-ion reserve batteries of the present invention capable of being activated at very low temperatures, even at or below 54 degrees C. as required for many munitions. In addition, to achieve fast activation, it is highly desirable to inject the electrolyte into the battery cell under pressure.

(9) To achieve the above goal of fast activation as well as very low temperature activation capability, as described below, pyrotechnic material is used to heat and inject the liquid electrolyte into the reassembled battery cell under pressure as illustrated in the schematic FIGURE (see U.S. Pat. No. 9,252,433, Issued on Feb. 2, 2016, the entire contents of which is incorporated herein by reference). In this embodiment, the pyrotechnic charge serves the following purposes. Firstly, it is used for battery activation, i.e., to release the stored liquid battery electrolyte into the battery cell. Secondly, it generates heat, which is used to heat the electrolyte to allow the battery to be activated and function at very low temperatures and at the same time enhance its penetration rate into the battery cell as well as its rate of diffusion. Thirdly, the pressure generated by the initiation of the pyrotechnic material is used to inject the electrolyte into the battery under pressure.

(10) A configuration of a pyrotechnic charge activated liquid reserve battery 100 is shown in the schematic drawing of the FIGURE. The pyrotechnic charge 102 serves the following purposes. Firstly, it is used for battery 100 activation, i.e., to release stored liquid battery electrolyte 104 into the battery cell 106. Secondly, it generates heat, which is used to heat the electrolyte 104 to allow the battery 100 to be activated and function at very low temperatures and at the same time enhance its penetration rate into the battery cell 106 as well as its rate of diffusion. Thirdly, the pressure generated by the initiation of the pyrotechnic material 102 is used to inject the electrolyte 104 into the battery cell 106 under pressure.

(11) The LIB based reserve battery illustrated in the FIGURE is constructed with two separate compartments, a battery cell compartment 100b and an electrolyte storage and injection mechanism compartment 100a. The battery housing 108 may have a circular or rectangular or other appropriately shaped cross-section. The liquid electrolyte 104 is stored in a collapsible (bellow like) metal storage unit 110. Outlets holes 112 are provided on a layer (plate) 114 separating the electrolyte storage compartment 100a from the battery cell compartment 100b and are sealed by relatively thin diaphragms (preferably metallic) 114a. Pyrotechnic materials 102, which can be formed in one or more layers, as shown in the FIGURE, are provided in a sealed volume between the collapsible liquid electrolyte storage unit 110 and the compartment walls 108a. The battery 100 is provided with either an initiation device 116 for igniting the pyrotechnic materials 110, which can be an inertial initiator for gun-fired applications or an electrical initiation element, such as those programmable electrical initiators developed by Omnitek Partners LLC. An advantage of such initiator is its small size and that it could be packaged inside the electrolyte compartment, thereby significantly reducing the power source size.

(12) The LIB based reserve battery 100 of the FIGURE is activated by igniting the pyrotechnic material 102 with the indicated (inertial or electrical) initiation device 116. The burning pyrotechnic material 102 will generate heat, which is used to heat the stored electrolyte 104, and generate pressure within the sealed volume between the collapsible liquid electrolyte storage unit 110 and the compartment walls 108a. The generated pressure would then act over the surface of the collapsible liquid electrolyte storage unit 110, forcing it to collapse, thereby forcing the heated and pressurized liquid electrolyte 104 to rupture the diaphragms 114a in the outlet holes 112 separating the liquid electrolyte 104 from the battery cell 106 and rapidly injecting the heated liquid electrolyte 104 into the battery cell 106 to activate the battery cell and provide power at the battery terminals 118.

(13) Thus, the LIB based reserve battery concept shown schematically in the FIGURE is constructed with two separate compartments, a battery cell compartment and an electrolyte storage and injection mechanism compartment. The battery housing may have a circular or rectangular or other appropriately shaped cross-section. The liquid electrolyte is stored in a collapsible (bellow like) metal storage unit. Outlets holes are provided on the layer (plate) separating the electrolyte storage unit from the battery cell and are sealed by relatively thin diaphragms (preferably metallic). Pyrotechnic materials, preferably in a layer as shown in the schematic of the FIGURE, are provided in the sealed volume between the collapsible liquid electrolyte storage unit and the compartment walls. The battery is provided with either an inertial initiator for gun-fired applications or an electrical initiation element for igniting the pyrotechnic material.

(14) The LIB based reserve battery of the FIGURE is activated by igniting the pyrotechnic material with the indicated (inertial or electrical) initiation device. The burning pyrotechnic material will generate heat, which is used to heat the stored electrolyte, and generate pressure within the sealed volume between the collapsible liquid electrolyte storage unit and the compartment walls. The generated pressure would then act over the surface of the collapsible liquid electrolyte storage unit, forcing it to collapse, thereby forcing the heated and pressurized liquid electrolyte to rupture the diaphragm separating it from the battery cell and rapidly injecting the heated liquid electrolyte into the battery cell.

(15) The collapsible liquid electrolyte storage unit is designed with a relatively large surface area to allow for rapid transfer of heat to the liquid electrolyte. The storage unit is also preferably designed to deform plastically under the generated pressure so that once the pressure has subsided, a minimal amount of the liquid electrolyte is returned back to the storage unit. Alternatively, particularly when the size of the battery allows, one-way valves may be used to prevent the liquid electrolyte's return.

(16) While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.