Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/656—Means for temperature control structurally associated with the cells characterised by the type of heat-exchange fluid
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/61—Types of temperature control
  • H01M10/613—Cooling or keeping cold
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/64—Heating or cooling; Temperature control characterised by the shape of the cells
  • H01M10/647—Prismatic or flat cells, e.g. pouch cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/654—Means for temperature control structurally associated with the cells located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/655—Solid structures for heat exchange or heat conduction
  • H01M10/6551—Surfaces specially adapted for heat dissipation or radiation, e.g. fins or coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/655—Solid structures for heat exchange or heat conduction
  • H01M10/6553—Terminals or leads
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/655—Solid structures for heat exchange or heat conduction
  • H01M10/6554—Rods or plates
  • H01M10/6555—Rods or plates arranged between the cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/62—Heating or cooling; Temperature control specially adapted for specific applications
  • H01M10/625—Vehicles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/651—Means for temperature control structurally associated with the cells characterised by parameters specified by a numeric value or mathematical formula, e.g. ratios, sizes or concentrations
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• Electrochemical batteries or cells are usually warmed up by the currents passing through them during charging as well as during discharging.
• the heating is depending on the intensity of the currents.
• the reason for the heating is mainly due to the inner resistance that characterize the battery.
• the irreversible electrode processes i.e. gas evolution that occurs especially at the end of the charging period, also warm up the battery.
• Batteries that are used for e.g. electrical trucks, electrical cars and submarines are often discharged and also charged by high currents and thus need to be cooled so that the maximum allowed temperature is not exceeded. For instance, cooling may be needed when a battery driven truck provided with only one exchange battery is used continuously during three shifts. In such cases the batteries have to be charged during 8 hours and thereafter immediately put on duty.
• the inner resistance of a battery can certainly be decreased by e.g. giving the current conducting parts larger cross section areas. This, however, causes a higher weight and a larger volume and it also increases the cost. Another way to reduce the inner resistance might be a decreased distance between the electrodes. The result will be less electrolyte and, at least when lead acid batteries are considered, a decreased capacity. Alkaline Ni/Cd batteries on the other hand will not suffer in the same way, since their capacities do not depend on the amount of electrolyte.
• a short electrode distance has the advantage that the so called oxygen recombination in the battery is enhanced.
• This phenomenon implies that oxygen, which is evolved at the positive electrodes, is transferred to the opposite negative electrodes, where it is electrochemically reduced to water. As a consequence, hydrogen can not be evolved on these electrodes surfaces. If this process is functioning well, there will be no gas evolution at all in the battery, which accordingly can be sealed. Since long there have been Ni/Cd batteries on the market working in sealed condition and lately also lead acid batteries. Sealed batteries are usually made with gelled or absorbed electrolyte and have thus following advantages: they need not to be topped up with water and the handling and management is easier and safer.
• the cooling of the batteries can be made in several ways. The most usual is of course to arrange the battery so that the surrounding air will circulate around the cells. This solution to the problem of cooling is however not always efficient enough. In stead one has to cool the interior of the cells. To achieve this one then has to e.g. arrange channels within the posts and the post straps through which cooling water is circulated. Another way is to put a plastic tube inside the cells in the electrolyte and above the electrodes and circulate the cooling water through the tube. These methods however allow the cells to be cooled only in their upper part. Further, the surface for heat transfer is rather small.
• Another way to enhance cooling is to allow parts of the electrodes to protrude through the lid of the cell jar and thus conduct the excess heat to the ambient air. Still another method is described in the Japanese patent 60-107274 (A), where a number of flat heat pipes are arranged in the battery cells at the side of the electrodes.
• the object of the invention described here is to arrange the cooling of the cells in a battery in an efficient way using larger surfaces for heat transfer without any change in neither the cell capacity nor the current distribution.
• the object of the invention is further to provide means to efficiently cool also sealed battery cells with absorbed or gelled electrolyte.
• the proposed method for cooling means a better electric conductivity of the electrode.
• Figure 1 shows a group of electrodes constituting a battery cell.
• Figure 2 shows an arrangement of heat transferring bodies connected to a post strap and a post with a cooling flange.
• Figure 3 shows an example of a plane of symmetry in a lead acid battery electrode A) a tubular electrode B) a flat electrode.
• Figure 4 shows an example of a heat transferring body according to the invention at an electrode parted in two symmetrical halves.
• Figure 5 shows a design of a heat transferring body intended for a plaited electrode.
• Figure 6 shows a battery with heat transferring bodies according to the invention and connected to a special post that is provided with a cooling flange.
• Figure 7 shows a battery with heat transferring bodies according to the invention and connected to the negative post that is provided with a cooling flange.
• An electrochemical cell of battery consists in principle of a container with the electrolyte and a number of electrodes (1,2) at least one of each polarity, parted by separators (3). Electrodes of equal polarity are connected with each other in parallel as is shown in figure 1. Usually the electrodes are connected in the upper part of the cell via a post strap (5) which is in its turn is connected to a post (6) protruding through the cell via special arrangements in the lid.
• the number of posts can be one or more for each kind of electrode.
• the electrodes are generally flat, porous plates (figure 3 B) though it e.g. in lead acid batteries also occurs that one kind of electrode can be built of a number of round poles of tubes (figure 3 A). These are arranged side by side to make a plate with mainly parallel surfaces. Each electrode is provided with a current collecting lug (4), often placed in the upper part of the electrode which by soldering, casting or screwing then is connected to the post strap (5).
• the electrodes are generally constructed so that an active material e.g. lead dioxide, nickel oxide or manganese dioxide in the positive electrode is fixed on to or around an electric conductor often especially designed to keep the active material in place.
• Such conductive (in-active) material could be made from lead or lead alloys, nickel screens, carbon- or graphite plates.
• the negative electrodes consist in the same way of active material, but of another composition, and inactive material as the current conductor.
• the separators (3) between the electrodes are made in e form of porous, electric non-conducting plates. They are made as thin as possible in order to reduce the inner resistance but at the same time being able to prevent short circuits between electrodes of opposite polarity.
• All electrodes in a battery cell are in most cases built symmetrically with reference to a plane (12) parting the electrode parallel to its extension with regard to width and height and perpendicular to the current flow. This will give the best current distribution within the cell and also the best utilization of the active material. Considering the height of the electrode, there could however be variations in the amounts of active and inactive materials. In some cases the electrodes could be plaited or globular, but his should not prevent the location of a symmetry plane with said definition.
• the plane of symmetry is not entirely parallel to a plane in the extension of the electrodes, but never the less the electrode is divided in two symmetric halves in a way that each of these half electrodes works against the opposite electrode.
• the object of the invention is to place heat conducting bodies (7) in said symmetry planes (12) of the electrodes, meaning that said heat conducting bodies do not influence the function of the electrode with respect to current distribution or active material utilization.
• heat conducting bodies made of e.g. copper sheets can be given dimensions equal to the symmetry plane of the whole electrode i.e. equal to the height and width of the electrode.
• An arrangement of this kind is thus not limited to the upper part of the cell with regard to its surface for heat transfer.
• the heat conducting bodies can even be larger than the surface of the electrodes and also be supported by the side walls of the container. If said bodies are attached to the negative electrodes of a lead acid battery by soldering against the current conducting grids, the heat conducting is further improved and besides, the current conduction of the grid will increase i.e. the inner resistance of the cell will decrease.
• Copper is an excellent heat conductor and thus this material is preferred in different geometrical forms.
• the heat conducting bodies can be given different kinds of surfaces enlargements, be made in plaited form or be perforated if this should fit the purpose of heat transfer.
• copper in contact with the positive electrode may corrode heavily especially if the electrolyte is sulphuric acid. It must in such cases be covered by durable, pore free material e.g. polyethylene. If copper is used as the heat conducting body in contact with the negative electrode it is generally protected by the cathodic potential and need not even in sulphuric acid be given any extra cover though it must be considered advantageous to cover the heat conducting copper plates with e.g. lead with a layer of tin in between.
• the invention is however not limited to copper as heat conducting material.
• the objective of the invention is further to provide these heat conducting bodies placed in the symmetry plane of the electrodes with lugs (9) and to connect these lugs to a post strap (8) and a post (10) in a way corresponding to the way the electrodes are connected.
• This post has a polarity if the heat conducting bodies are in electrical contact with any of the electrodes but is nonconducting if said bodies are isolated by e.g. a thin layer of plastics.
• the connection can of course be made to more than one post of same polarity.
• the heat conducting bodies can be placed in both the negative and the positive electrodes and being connected to the posts of corresponding polarity.
• the posts can be provided with cooling flages (11) and the heat can be quickly dissipated from said post and said cooling flange by e.g. air blowing or by cooling water that flows through or around the post. Cooling can also be enhanced by placing the battery in water, especially if it is of the saled type.
• the posts of the battery are usually protruding the lid of the container (figure 7).
• the position of the post or posts connected to the heat conducting bodies is however not limited to the lid but can be as well in the walls as in the bottom of the container. This arrangement is advantageous if there should not be room for said post and cooling flage on the upper area of the cell.
• FIG. 8 An alternative design (figure 8) in accordance with the invention is to connect the heat conducting bodies to that post which is connected to one kind of electrode or the other and to apply a cooling flange to this post.
• cooling arrangement in a preferred embodiment of the cooling arrangement according to the invention are lead copper sheets (7), 0,5 mm thick and provided with lugs (9), interleaved between double negative electrodes (13) and soldered to said electrodes.
• the connection to a lead coated copper post (10) with circular cross section is made via a post strap (8) also made form lead coated copper and which is located above the electrodes and perpendicular to said electrodes.
• the post of the heat conducting bodies is protruding in the middle of the lid and provided with a cooling flange of known construction.
• electrodes in accordance with the Swedish Patent Appl. 6300141-2 are plastic covered sheets of copper, 0,5 mm thick, placed between the positive half electrodes.
• the copper sheets have been given a plaited form that coincide with the form of the electrode and are connected to a post with cooling flange as described above.
• the material chosen for the heat conducting bodies is preferential copper since the hat conducting of this material per volume is about ten times higher compared to lead. To obtain a heat transfer effect corresponding to said prefered embodiment one should need a 5 mm thick sheet of lead between the double negative electrodes. In battery constructions where weight saving is important it could be more advantageous to make the heat conducting bodies from aluminium covered by e.g. a thin layer of plastic. Aluminium has about twice the heat conducting capability per weight compared to copper. Table 1. Heat conduction in W/cm, K for some materials at 298 K according to Handbook of Chemistry and Physics 1978-79.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Secondary Cells (AREA)
• Connection Of Batteries Or Terminals (AREA)
• Hybrid Cells (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 1988
  • 1988-04-11 SE SE8801318A patent/SE467602B/sv not_active IP Right Cessation
• 1989
  • 1989-04-11 EP EP89904869A patent/EP0403569A1/en not_active Withdrawn
  • 1989-04-11 WO PCT/SE1989/000200 patent/WO1989010011A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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