Internal built-in tab fuse for secondary battery cell and secondary battery cell comprising such internal fuse

Abstract

The application relates to an internal built-in tab fuse for a secondary battery cell and a secondary battery cell including such an internal fuse. A fuse, such as a fuse for preventing thermal runaway, is a built-in electrode tab of a current collector of a secondary battery cell, and is located inside the secondary battery cell. In some embodiments, the built-in tab fuse of the present disclosure includes a one-piece tab portion that is integral with a current collector and forms a whole, and a free-standing tab component that is spaced apart from the one-piece tab portion by a gap. A fuse spans the gap. In some embodiments, the fuse comprises a material that is different from the material constituting the current collector. In some embodiments, a built-in tab fuse of the present disclosure is covered with an insulating material.

Description

[0001] field

[0002] The present disclosure generally relates to the field of secondary battery safety, and more particularly to an internal built-in tab fuse for a secondary battery cell, and a secondary battery cell including such an internal fuse.

[0003] background

[0004] Lithium (Li) metal batteries have high energy density (>300Wh / kg) and are considered to be the next generation battery technology for many applications, including electric vehicles, such as electric cars, trucks, and electric aircraft. Due to the possibility of lithium dendrite formation during cycling, lithium metal battery cells may randomly form internal short circuits within the battery cell, resulting in uncontrolled reactions, heat generation, and then thermal runaway. A solution is needed to mitigate or reduce the risk of battery cell explosion by limiting the total amount of heat generation and the rate of heat generation (per unit time) so that the heat dissipation can effectively offset the heat generation, which will reduce the severity of thermal runaway incidents.

[0005] Overview

[0006] In one embodiment, the present disclosure relates to a secondary battery cell comprising: a container; an internal core located within the container, comprising a plurality of current collectors and a plurality of fused tabs corresponding to the plurality of current collectors, wherein each fused tab comprises: an integral tab portion directly connected to a corresponding one of the current collectors and comprised of a first conductive material; a freestanding tab component separated from the integral tab portion so as to define a gap between the freestanding tab component and the integral tab portion, the freestanding tab component being comprised of a second conductive material; and a built-in tab fuse comprising a third conductive material, the third conductive material being different from each of the first conductive material and the second conductive material and spanning the gap so as to electrically connect the integral tab portion and the freestanding tab component to each other and define a melting area between the integral tab portion and the freestanding tab component.

[0007] In another embodiment, the present disclosure relates to a secondary battery cell comprising a container; an internal core located within the container, comprising a plurality of current collectors and a plurality of fuse blades corresponding to the plurality of current collectors, wherein each fuse blade is designed and configured not to melt under an operating current, and comprises a built-in blade fuse designed and configured to melt under a predetermined excess electrical current greater than each operating current; and a dielectric tape applied to the built-in blade fuse.

[0008] In yet another embodiment, the present disclosure relates to a method for manufacturing a secondary battery cell having an internal core contained within a container, the internal core including a plurality of current collectors, each current collector having a tab positioned within the container. The method includes, for each fuse tab: providing an integral tab portion integral with a corresponding one of the current collectors; providing a separate tab component separated from the integral tab portion by a gap; and forming a built-in tab fuse that extends across the gap and electrically connects the integral tab portion and the separate tab component.

[0009] In another embodiment, the present disclosure relates to a method for designing an internal fuse insert for a secondary battery, wherein the fuse insert includes a built-in insert fuse and has an integral insert portion and a separate insert component. The method includes determining a maximum design current; determining electrical characteristics of a conductive tape; and based on the maximum design current: selecting a gap width between the integral insert portion and the separate insert component to define a melting region of the conductive tape; and selecting an amount of conductive tape disposed in the melting region such that, when the conductive tape is disposed across the gap width, the conductive tape melts when a current flowing in the fuse insert exceeds the maximum design current. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For the purpose of illustration, the accompanying drawings show various aspects of one or more embodiments of the present disclosure. It should be understood, however, that the scope of the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, in which:

[0011] Figure 1 Diagrams illustrating example secondary battery cells of the present disclosure having internally fused current collector tabs on corresponding cathode electrodes, showing the cell before an internal short circuit (a), the cell during an internal short circuit but before the fuse has blown (b), and the cell after the fuse has blown (c);

[0012] Figure 2Graphs of current versus time, cell voltage versus time, and temperature versus time (from top to bottom) for an example short circuit test of a 4.2 Ah lithium metal secondary battery cell;

[0013] Figure 3 Figures illustrating four cathodes, one cathode with a conventional cathode blade (a), one cathode with a first built-in blade fuse (b), one cathode with a second built-in blade fuse (c), and one cathode with a third built-in blade fuse (d, d-1, d-2), where Figures d-1 and d-2 illustrate the fuses covered by a tape that provides blade reinforcement and thermal insulation;

[0014] Figure 4 Figures illustrating a method of making an example electrode using a conductive ribbon to make a fusible current collector tab, wherein Figures a-1 and a-2 are side and front views, respectively, of the electrode, Figure b is a front view of the electrode having a gap in the fusible current collector tab, and Figures c-1 and c-2 are front and side views, respectively, of the cathode of the completed fusible current collector tab with the conductive ribbon spanning the gap;

[0015] Figure 5A for Figure 4 The enlarged partial cross-sectional views of the fuse collector inserts of Figures c-1 and c-2 of FIG. 1 and FIG. 2 show example details of the fuse;

[0016] Figure 5B for Figure 4 Figures c-1 and c-2 of FIG are partial enlarged front views of the fuse collector inserts, showing example details of the fuse;

[0017] Figure 6 A diagram illustrating an example secondary battery cell including a fusible current collector tab having a fuse including a metal film applied to a dielectric component; and

[0018] Figure 7 A diagram illustrating an example secondary battery cell including a fusible current collector tab having a fuse including a semiconductor.

[0019] Detailed description

[0020] The entire contents of the appended claims are incorporated into this detailed description section by reference and should be considered as original content herein.

[0021] Overview

[0022] In certain aspects, the present disclosure relates to a secondary battery cell having a current-limiting built-in plug fuse inside. Conventional pouch-shaped battery cells have a multi-layer core structure, including a stacked structure of repeated anode / spacer / cathode / spacer sub-stacks. Traditionally, external fuses are used to limit current to protect battery cells during external short circuits. In this conventional design, the fuse can be placed on the cathode plug side or the anode plug side, or the fuse can be placed on each of these two sides. When an external short circuit occurs, the battery cell will discharge rapidly at a low external resistance with a very high current (proportional to the cathode / anode interface area). The current (electron flow) will flow from the anode to the cathode through the plug and externally through the fuse. The large amount of heat generated by the high current will activate the fuse to disconnect the circuit, which will effectively cut off the current, stop the battery cell electrochemical reaction, and thus further prevent heat generation. By using a fuse to disconnect the circuit and limit heat generation, the battery cell will not enter a thermal runaway state.

[0023] An example of such an external fuse design concept is to use the cathode aluminum tab itself as a fuse. When a lithium metal battery (LMB) is externally short-circuited, the high current flowing through the aluminum cathode tab generates sufficient heat (Q = I 2 Rt) to melt the aluminum insert (aluminum: melting point is 660.32°C), thereby disconnecting the circuit. By controlling the cross-sectional area of ​​the aluminum insert and the length of the aluminum insert, the resistance (R) can be adjusted according to the heat generation (Q) of the melting insert. Once the insert is melted, there will be no fire or explosion. The above fuse design concept is only effective in the case of an external short circuit. When an internal short circuit occurs in the battery cell (for example, a short circuit caused by lithium dendrites that grow into a penetrating spacer), the external fuse will not be able to cut off the current inside the battery cell, and therefore cannot prevent the battery cell from entering a thermal runaway state.

[0024] This disclosure introduces secondary battery cells that incorporate internal, built-in fuses on individual current collector tabs within the cell's sealed container to individually limit the current flowing into and out of each electrode. Regardless of the location of the internal short circuit, the maximum current flowing through each individual current collector tab is limited by the associated internal, built-in fuse.

[0025] Figure 1FIG. 1 illustrates the overall arrangement of a pouch-type secondary battery cell 100, or simply a "battery cell," herein, having a stacked core 104 consisting of five anodes 108 and four cathodes 112 separated by spacers 116 (only a few are labeled to avoid cluttering the diagram) contained within a container 120. In this example, the battery cell 100 uses a non-flammable liquid electrolyte 124 that is substantially distributed throughout the container 120, but the electrolyte can be of a different type, such as a gel electrolyte or a solid electrolyte, or any combination or subcombination of different electrolyte types. Each anode 108 includes a current collector 108C (only a pair are labeled to avoid cluttering the diagram) and an anode active material 108M operatively connected to the current collector (only a few locations are labeled to avoid cluttering the diagram), and each current collector has a tab 108T (only a pair are labeled to avoid cluttering the diagram) for electrically connecting the current collector to an anode output terminal 124. The anode active material 108M can be any suitable anode active material, such as, for example, lithium metal, graphite or carbon, silicon, tin, tin oxide, etc. However, there is essentially no limitation on the type of anode active material 108M. In this example, the tab 108T is integrally formed with the current collector 108C and is made of the same material as the current collector 108C, which in this example is copper, but other materials may also be used.

[0026] Similarly, each cathode 112 includes a current collector 112C (detailed enlarged view) and a cathode active material 112M (detailed enlarged view) in operative communication with the current collector, each current collector having a fuse plug 112T (detailed enlarged view) for electrically connecting the current collector to the cathode output terminal 128. The cathode active material 112M (detailed enlarged view) can be any suitable cathode active material, such as, for example, a plated-strip material, such as, for example, a metal oxide-based material, such as lithium cobalt oxide (LCO), nickel cobalt aluminum oxide (NCA), nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), lithium iron manganese phosphate (LFMP), etc. There is essentially no limitation on the type of cathode active material 112M.

[0027] In this example, each fusible insert 112T has: an integral insert portion 112TI (detail enlarged view), which is integrally formed with the current collector 112C and made of the same material as the current collector 112C; a separate insert component 112TF (detail enlarged view) spaced apart from the integral insert portion; and a insert fuse 112F (detail enlarged view) extending from the integral insert portion to the separate insert component. In this example, the integral insert portion 112TI and the current collector 112C are aluminum, but other materials can also be used. Also in this example, the separate insert component 112TF is aluminum, but in other embodiments it can be another material. Various embodiments of the insert fuse 112F are described below.

[0028] Example external short circuit test results are as follows Figure 2 As shown. During the external short circuit test of a 4.2Ah battery cell, the cathode tab broke within 5 seconds with an average current of 200 amperes (external resistance of 5mΩ). In this example, the aluminum tab exposed outside the battery cell pouch is approximately 7 mm wide, 0.2 mm thick, and 15 mm long. Based on the aluminum density of 2.7g / cc, the total weight of the above cathode tab is approximately 0.0567g. The relationship between heat generation (Q), resistance (R) / current (I), and time (t) is as follows: Q=I 2 Rt. The resistivity of aluminum is 2.82×10 -8 Ωm, which gives the cathode sheet resistance as 3.02×10 -4 Ω. Under these conditions, the heat capacity of aluminum, Q, is estimated to be approximately 60.4 J, or approximately 1065.3 J / g. Aluminum has a heat capacity of 0.897 J / g K, which yields a temperature rise of approximately 1187.6°C under adiabatic conditions. Even if some heat were dissipated under realistic (i.e., non-adiabatic) test conditions, this estimated temperature rise would likely melt the aluminum insert (simply increasing the temperature by 635°C from 25°C to the aluminum melting point of 660.32°C).

[0029] Because heat dissipation depends on many factors, including ambient conditions, temperature, airflow, battery cell design, internal structure, and materials, it is impossible to accurately predict heat dissipation. Experimentation is necessary to determine whether the heat generated during an external short circuit is sufficient to melt the aluminum tabs. While there is some uncertainty in accurately determining these parameters, the basic principles apply to all battery cell designs to reduce the risk of thermal runaway under external short-circuit conditions. Alternatively, an actual fuse can be used externally to achieve the same function.

[0030] The above principle can also be applied to each internal built-in plug fuse of the present disclosure, such as Figure 1 When an internal short circuit occurs in a battery cell (eg, an internal short circuit caused by lithium dendrites), the internal short circuit may occur at substantially any location within the battery cell. Figure 1 In the battery cell 100 of FIG. a, during an internal short circuit event, the directions of electron and lithium ion flow are as follows: Figure 1As shown in Figure b, arrows 132 and 132S represent electron flow, while arrows 136 (only a few are marked to avoid cluttering the figure) represent lithium ion flow through the electrolyte 124. Arrow 132 represents non-short-circuit electron flow, while arrow 132S represents short-circuit electron flow. Due to the high current flowing through the short-circuit point 144 shown by arrow 140, the short-circuit point 144 will become hot. The greater the current 140 flowing through the short-circuit point 144, the higher the temperature rise at this local point. If heat generation becomes faster than heat dissipation, a thermal runaway reaction will begin, causing the battery cell 100 to catch fire or explode. Therefore, the key to avoiding thermal runaway is to limit the magnitude of the current 140 flowing through the short-circuit point 144 to keep heat generation slower than heat dissipation.

[0031] The current can be controlled by using Figure 1 This can be achieved by using an internal built-in plug fuse 112F on each separate fused cathode plug 112T as shown in FIG. b (similar internal built-in plug fuses can also be added to each anode plug instead). Figure 1 As shown in Figure b, the total current 140 flowing through the short-circuit point 144 is equal to the discharge current from all cathode / anode interfaces involved in the lithium ion flow 136. The magnitude of the current 140 flowing through the short-circuited cathode-anode tab pair will be much higher than the magnitude of the current passing through other cathode-anode tab pairs, as shown by the thick arrow representing the current 132S. Therefore, the short-circuited cathode-anode tab pair 148 can be distinguished from other cathode-anode tab pairs (unmarked) by the magnitude of the current 132S. As mentioned in the example of an external fuse where the fuse is located outside the container above, in some embodiments, the aluminum fuse tab 112T for each individual cathode 112 itself can also be used as a built-in tab fuse to limit the current by controlling the cross-sectional area and length of the aluminum fuse tab 112T. Based on Q=I 2 The cathode plug can be designed to have a preset resistance (R) so that the plug can melt within a certain time (t) at a short circuit current magnitude above a threshold level. By melting the aluminum fuse plug 112R, the discharge current from the other cathode-anode pairs is cut off, and by activating (e.g., melting) the corresponding plug fuse 112F (1) ( Figure 1 c), the short circuit current 140 will be limited to only the locally shorted cathode-anode pair 148, thereby limiting heat generation.

[0032] Lithium metal batteries (LMBs) and lithium ion batteries (LIBs) experience internal short circuits when lithium dendrites grow to penetrate the spacer or any other contaminant particles penetrate the spacer. Internal short circuits can vary from soft short circuits to hard short circuits and are generally unpredictable. Depending on the severity of the short circuit, these internal short circuits may produce uncontrollable heat generation. Soft short circuits generate less heat per unit time and have a lower safety risk because heat dissipation is faster than heat generation. As the short circuit becomes more severe, more heat will be generated and reach a point where heat generation is faster than heat dissipation, resulting in thermal runaway. In the worst case, a hard short circuit can cause rapid heat generation and cause the battery cell to explode. Since it is an internal short circuit, the battery management system (BMS) cannot be used to stop the process and therefore thermal runaway cannot be prevented. The purpose of the present disclosure is to introduce a battery cell design with a separate tab fuse built into the electrode tab inside the battery cell to limit the short circuit current to a level where the heat generation rate is lower than the heat dissipation rate, thereby reducing the risk of thermal runaway in the battery cell.

[0033] Figure 1 The general principle disclosed in Figures a-c of the present invention is to activate the built-in plug-in fuse (specifically Figure 1 The blade fuse 112F in the example of Figures a-c cuts off the current to limit heat generation. In principle, this built-in blade fuse design can define a maximum current. The maximum current can be the maximum current density (mA / cm2) at a single cathode-anode interface. 2 ) multiplied by the total surface area of ​​the cathode of the entire battery cell. During normal operation, the current flowing through each built-in blade fuse is insufficient to activate the built-in blade fuse (i.e., less than the maximum current that the blade fuse can carry without melting); therefore, the presence of the built-in blade fuse does not affect the operation of the battery cell. However, when an internal short circuit occurs, because the current is generated through multiple cathode / anode layers with a larger total cathode surface area, the current flowing through the blade of the short-circuited electrode pair (e.g., Figure 1 b, thick arrow 132S) will exceed the maximum allowable current of the plug fuse. In this case, the relevant plug fuse will be activated (e.g., the fuse material melts) and cut off the excess current from the rest of the battery cell (e.g., see Figure 1 This design concept will mitigate thermal runaway by limiting the rate of heat generation.

[0034] Example Embodiments

[0035] There are many ways to implement the internal built-in plug fuse of the present disclosure. Examples of plug configurations for built-in plug fuses are as follows: Figure 3 shown. Figure 3FIG. 1 shows an electrode 300 having a conventional one-piece tab 300T integral with a current collector (not shown; located behind the electrode active material 300M). As shown in the one-piece tab 300T, conventional one-piece tabs are generally rectangular. To illustrate the inclusion of a fuse in the tab, Figure 3 Several examples of built-in blade fuses 304F, 308F, and 312F are shown, each of which is part of a corresponding fuse blade 304T, 308T, and 312T, which is integral with a corresponding electrode (not shown) and made of a suitable conductive material such as metal (e.g., aluminum, copper, etc.). Figure 3 In FIG. b, the built-in blade fuse 304F is configured to provide a long and narrow conductive path 304P. Figure 3 In FIG. c, the built-in blade fuse 308F is configured to provide a narrow conductive path 308P and Figure 3 In FIG. d, the internal blade fuse 312F has an opening 312O so as to define two narrow conductive paths 312P on either side of the opening. In some embodiments, the primary design concept is to modify the electrical properties of the blades in an area to increase resistance, thereby limiting the maximum current that can flow through that area during an internal short circuit, effectively creating a built-in blade fuse. The built-in blade fuse will melt when the short circuit current exceeds a predetermined threshold, thereby breaking the circuit (see, for example, Figure 1 c and disconnection of fuse 112F(1). At the same time, the resistance at the modified area (i.e., the built-in blade fuse) does not significantly affect the power performance of the battery cell under normal operating conditions.

[0036] There are many tab designs that can achieve this goal, and the examples provided in this section are only for illustration of the design concepts. In some embodiments, the electrical modification to the tab includes reducing the cross-sectional area of ​​the tab, which can potentially weaken the mechanical strength of the tab and can affect manufacturability, depending on the specific battery cell design. Therefore, in some embodiments, for manufacturability, it may be desirable / necessary to enhance the mechanical strength of the built-in tab fuse by placing dielectric tape (which can also be thermally insulating) on ​​one or both wide sides of the tab. This is in Figure 3 Zhongzai Figure 3 The d-1 graph and Figure 3 d-2, where the dielectric tape 316 surrounds the fuse plug 312T ( Figure 3 Although not shown, Figure 3 Figure b and Figure 3The built-in fuses 304F and 308F of FIG. c can be similarly reinforced, electrically insulated, and / or thermally insulated by adding dielectric tape applied to the corresponding fuse blades 304T and 308T, respectively. Examples of dielectric tape suitable for use as dielectric tape 316 include, but are not limited to: tapes, polyimide tapes, acetate tapes, silicone tapes, and PTFE tapes (e.g. ) tape, etc. One factor in selecting the tape is the compatibility of the tape material with the chemistry of the battery cell in question.

[0037] Another example of a built-in plug-in fuse is the use of a conductive tape, which is used as a built-in plug-in fuse. Typically, the conductive tape acts as a current regulator, which is conductive but has a higher resistance than the material of the associated current collecting tabs. At high currents, the conductive tape will polarize the battery cell voltage, thereby limiting the current. As will be readily understood by those skilled in the art, any materials and components with these properties can be used to achieve the same results. Examples include semiconductor materials, resistors, and conventional fuses. The conductivity of each of these materials / components can be adjusted based on the battery cell design to meet the requirements for limiting current. Figure 4 The c-1 graph and Figure 4 An example involving a conductive tape is shown in FIG. c-2, which shows an electrode 400 including a current collector 400C and an electrode active material 400M. An example involving a semiconductor is shown in FIG. Figure 7 shown.

[0038] refer to Figure 4 As mentioned above, the electrode 400 can be a cathode or an anode, and accordingly, the electrode active material 400M can be a cathode active material or an anode active material. Examples of cathode active materials and anode active materials suitable for the electrode active material 400M are discussed above. The current collector 400C can be made of any suitable conductive material (e.g., a metal, such as copper or aluminum). The electrode 400 includes a fuse plug 400T, which is composed of an integral plug portion 400TI, an independent plug component 400TF separated from the integral plug portion by a gap G, and a built-in plug fuse 400F composed of a conductive strip 404. In this example, the conductive strip 404 has a predetermined resistance, which can be adjusted by its thickness, the size of the gap G between the two proximal ends of the integral plug portion 400TI and the independent plug component 400TF, or the use of strips with different conductivity, and any combination or sub-combination of these.

[0039] In this example, the resistivity of the conductive tape 404 is higher than the resistivity of the conductive material (e.g., aluminum or copper) of the integrated tab portion 400TI and the stand-alone tab component 400TF. Under short-circuit conditions (external or internal), the controlled resistance of the conductive tape 404 will limit the maximum current during the short circuit of the corresponding battery cell (not shown), resulting in a lower heat generation rate. Under high temperature conditions, the conductive tape 404 will melt, breaking the circuit and stopping the flow of current between the integrated tab portion 400TI and the stand-alone tab component 400TF. In addition, the conductivity of the conductive tape 404 is high enough to enable the corresponding battery cell to be used under normal operating conditions. One option associated with this example is to use a positive temperature coefficient (PTC) material as the conductive tape 404, which will significantly increase the resistivity when the temperature of the fuse tab 400T increases due to high current under short-circuit conditions. By increasing the resistivity according to temperature, the magnitude of the current is limited, resulting in a lower heat generation rate. Note that the conductive tape 404 can be an adhesive tape having a suitable conductive adhesive or a non-adhesive tape that can be secured to each of the integral tab portion 400TI and the separate tab component 400TF in any suitable manner, such as welding, heat sealing, or soldering.

[0040] like Figure 4 As shown, as an example, a conductive strip 404 is used to provide a fuse 400F with a built-in blade fuse ( Figure 4 The method of the fuse plug 400T of FIG. 4 (c-1 and FIG. 4 c-2) can start from the electrode 400 with the complete plug 408, such as Figure 4 A-1 graph and Figure 4 As shown in FIG. a-2 of FIG. Electrode 400 can be any suitable electrode, including a conventional electrode, an electrode of an existing battery cell design, or an electrode of a new battery cell design. Figure 4 As shown in FIG. 2 , for example, by cutting the insert using any suitable cutting process, the insert is divided into two parts, namely, an integrated insert portion 400TI and a separate insert component 400TF. The integrated insert portion 400TI remains integral with the collector 400C. Although the entire insert 408 can be cut to produce a built-in insert fuse 400F, relative to Figure 4 Figure a-1, Figure 4 Figure a-2 and Figure 4 b, an alternative approach would be to provide the electrode 400 with a shorter tab than shown (in relation to Figure 4 in the vertical direction) (e.g., only Figure 4 b) and then provide a separate insert portion (e.g. Figure 4 Figure c-1, Figure 4 The c-2 graph and Figure 4b in each of the independent plug parts 400TF), the size of the separate plug part is suitable for making the final fuse plug 400T, that is, the final desired total length, such as Figure 4 The c-1 graph and Figure 4 Each of the c-2 diagrams is shown in FIG.

[0041] Once the entire tab 408 has been cut to form the freestanding tab component 400TF or the separate portions for the freestanding tab component have been provided, the freestanding tab component and the integral tab portion 400TI are positioned relative to each other so as to form the desired gap G between the freestanding tab component and the integral tab portion 400TI, as shown in FIG. Figure 4 of Figure 4 Figure b, Figure 4 The c-1 graph and Figure 4 As shown in each of Figures c-2 of FIG. As described above, the size of the gap G between the integral tab portion 400TI and the independent tab component 400TF can be one of the variables used to adjust the maximum current that the internal tab fuse 400F can withstand before the fuse melts and opens the circuit. Once the integral tab portion 400TI and the independent tab component 400TF are properly positioned relative to each other to form the desired gap G, one or more conductive ribbons 404 are engaged with and secured to both the integral tab portion and the independent tab component, thereby spanning the gap. Figure 5A and Figure 5B Examples of how the conductive ribbon 404 may be configured, along with the integral tab portion 400TI and the freestanding tab component 400TF are illustrated in greater detail.

[0042] Reference Figure 5A and Figure 5B , these figures show that Figure 4 The c-1 graph and Figure 4Figure c-2 of FIG. 1 illustrates some details of an example electrode 500 of a conductive ribbon-type internal blade fuse 500F. In this example, electrode 500 includes a current collector 500C, electrode active material 500M applied to each face of the current collector, and a fuse blade 500T having an internal blade fuse 500F comprised of a conductive ribbon 504. Internal blade fuse 500F includes a separate blade component 500TF and an integral blade portion 500TI, which are separated by a gap 508 having a width Wg and further define a length Lm of a melting region 512 of conductive ribbon 504. Conductive ribbon 504 melts when subjected to a current exceeding the maximum current at which the melting region is designed to remain unmelted. As will be readily understood by those skilled in the art, the total cross-sectional area and length Lm of the conductive tape 504 in the melt region 512, together with the relevant electrical properties of the conductive tape, will determine the maximum amount of current at which the conductive tape can remain unmelted in the melt region, thereby limiting the amount of current at which the built-in blade fuse 500F will open the circuit.

[0043] As described above, the width Wg of gap 508, and therefore the length Lm of melt region 512 of conductive ribbon 504, is one of several variables that contribute to regulating the resistance of the conductive ribbon. These variables contribute to the melting of the conductive ribbon, thereby breaking the circuit and preventing further resistive overheating. As will be readily understood by those skilled in the art, gap width Wg and melt region length Lm can be any value suitable for a particular design and will depend on a variety of factors, including, but not limited to, the resistivity of conductive ribbon 504 and the material of fuse insert 500T, the transverse cross-sectional area of ​​the stand-alone insert component 500TF and the integral insert portion 500TI, the number of layers of conductive ribbon 504, the maximum design current allowed to flow through melt region 512, and the thermal resistivity curve when using PTC materials. Given a set of design parameters, those skilled in the art will be able to determine appropriate values ​​for gap width Wg and melt region length Lm without undue experimentation. Of course, some testing may be required, but no more than routine testing common in the art.

[0044] Also like Figure 5A and Figure 5BAs shown, the distances at which the conductive tape 504 overlaps the stand-alone tab component 500TF and the integrated tab portion 500TI, respectively, are Of and Oi, which can be the same or different from each other. The values ​​of these overlapping distances Of and Oi can be any value suitable for a particular application. Generally, the overlapping distances Of and Oi need to be large enough to carry the amount of current required to ensure that any melting that occurs in the conductive tape 504 occurs in the melting region 512. As will be readily understood by those skilled in the art, the overlapping distances Of and Oi can be determined based on a number of parameters, including the conductivity of the conductive tape 504, the resistivity of the interface between the conductive tape and each of the stand-alone tab component 500TF and the integrated tab portion 500TI, and the amount of current that must be carried between the conductive tape and each of the stand-alone tab component and the integrated tab portion.

[0045] like Figure 5B As shown, the length Lt of the conductive strip 504 along the direction of the tab width Wt can be varied to suit a particular design. Figure 5B Two examples are shown, one in which the conductive tape 504 (solid line) is wrapped completely around the fusible insert 500T once, such that the tape length Lt1 along one face of the fusible insert is substantially equal to the insert width Wt, and another in which the conductive tape length Lt2 is shorter than the insert width Wt. Many other possibilities exist. Depending on the characteristics of the conductive tape 504, one, two, or more layers of conductive tape may be required. When the length Lt1 of the conductive tape 504 is equal to the insert width Wt and two or more layers are desired, these layers can be provided by wrapping the conductive tape around the fusible insert 500T more than once until the desired number of layers are present on each face of the fusible insert. When the length Lt2 of the conductive tape 504 is less than the insert width Wt and two or more layers are desired, these layers can be provided by simply affixing one or more layers on top of layers directly adhered to the freestanding insert component 500TF and the integrated insert portion 500TI.

[0046] although Figure 5A and Figure 5B Not shown, but noted, in some embodiments, the conductive tape 504 may be covered with a thermally insulating dielectric tape to limit and control the heating of the melt region 512 of the conductive tape. In some embodiments, the thermally insulating dielectric tape may extend over one or both portions of the freestanding tab member 500TF and the integral tab portion 500TI that are not covered by the conductive tape 504. For example, see Figure 3 The d-1 graph and Figure 3 See Figure d-2 for an example of an application of the thermal insulation dielectric tape 316.

[0047] Those skilled in the art will readily understand that Figure 5A and Figure 5BEmbodiments fabricated using the principles shown will need to be designed based on the design parameters of the specific battery cell in question, such as, but not limited to, the design output current, maximum charge current, tab width Wt, and tab thickness. Using these and / or other parameters, one skilled in the art will be able to determine parameters associated with the conductive ribbon 504, including, but not limited to, the type of ribbon (e.g., based on its electrical properties), gap width Wg / melted region length Lm, overlap distances Of and Oi, and the number of ribbon layers. Due to the wide variety of battery cell and ribbon design parameters, one skilled in the art will need to perform ordinary engineering testing, rather than undue experimentation, to devise one or more suitable designs for the fusible insert 500T in question.

[0048] Figure 6 An example subassembly 600 of a battery cell (not shown) is shown, wherein the subassembly consists of a cathode 604 and an anode 608 with a dielectric spacer 612 between the cathode 604 and the anode 608. The cathode 604, the anode 608, and the spacer 612 can be of any suitable type, such as any of the types described above. Furthermore, the battery cell (not shown) can be of any suitable type, such as any of the battery cells described above. In this example, the anode 608 has a conventional rectangular tab 608T integrally formed with a current collector 608C, and the cathode 604 includes a fuse tab 604T comprising an integral tab portion 604TI integrally formed with the current collector 604C, a separate tab member 604TF separated from the integral tab portion by a gap G, and a built-in tab fuse 604F spanning the gap. In this example, the built-in blade fuse 604F includes a substrate 616 extending between an integral blade portion 604TI and a separate blade component 604TF and at least one conductive layer 620 applied to the substrate 616 and each of the integral blade portion and the separate blade component. For example, a second metal layer (not shown) may be applied to the back of the built-in blade fuse 604F. Figure 6 The conductive layer 620 can be made of any suitable material (e.g., tin, silver, or metallic paint, etc.). In this example, the substrate 616 provides physical strength for the built-in fuse 604F and provides a surface to which the conductive layer 620 can be applied. The substrate 616 can be made of any suitable dielectric material (e.g., a dielectric polymer, etc.). It should be noted that in other embodiments, the fuse 604T can be moved to the anode 608, or similar fuses can be used on both the cathode 604 and the anode.

[0049] Figure 7Another example subassembly 700 of a battery cell (not shown) is shown, wherein the subassembly is composed of a cathode 704 and an anode 708 with a dielectric spacer 712 between the cathode 704 and the anode 708. The cathode 704, the anode 708, and the spacer 712 can be of any suitable type, such as any of the types described above. In addition, the battery cell (not shown) can be of any suitable type, such as any of the battery cells described above. In this example, the anode 708 has a conventional rectangular tab 708T integrally formed with a current collector 708C, and the cathode 704 includes a fuse tab 704T, which includes an integral tab portion 704TI integrally formed with the current collector 704C, a separate tab component 704TF separated from the integral tab portion by a gap G, and a built-in tab fuse 704F spanning the gap. In this example, the built-in blade fuse 704F includes at least one semiconductor component 716 extending between the integral blade portion 704TI and the separate blade member 704TF. For example, a second semiconductor component (not shown) may be applied to the back of the built-in blade fuse 704F. Figure 7 The semiconductor component 716 can be made of any suitable semiconductor. In some embodiments, the semiconductor component 716 can be a freestanding component, such as a sheet. In some embodiments, the semiconductor component 716 can include a substrate (not shown, but can be Figure 6 704F) has a semiconductor applied thereto, for example, using any known method for applying semiconductor material to a substrate. In this example, semiconductor component 716 provides physical strength to built-in fuse 704F and provides the conductive material that acts as a fuse. It should be noted that in other embodiments, fuse blade 704T can be moved to anode 708, or similar fuse blades can be used on both cathode 704 and anode.

[0050] In certain aspects, the present disclosure relates to a secondary battery cell comprising: a container; an internal core located within the container, comprising a plurality of current collectors and a plurality of fuse plugs corresponding to the plurality of current collectors, wherein each fuse plug comprises: an integral plug portion, which is directly connected to a corresponding current collector in the current collectors and is composed of a first conductive material; an independent plug component, which is separated from the integral plug portion so as to define a gap between the independent plug component and the integral plug portion, and the independent plug component is composed of a second conductive material; and a built-in plug fuse, which comprises a third conductive material, which is different from each of the first conductive material and the second conductive material and spans the gap so as to electrically connect the integral plug portion and the independent plug component to each other and define a melting area between the integral plug portion and the independent plug component.

[0051] In one or more embodiments of the secondary battery cell, the conductive strap includes a positive temperature coefficient material.

[0052] In one or more embodiments of the secondary battery cell, the conductive tape is selected from the group consisting of an adhesive tape, a thermal bonding tape, and a weld bonding tape.

[0053] In one or more embodiments of the secondary battery cell, the conductive tape of the built-in blade fuse is provided in at least two layers.

[0054] In one or more embodiments of the secondary battery cell, the conductive tape of the built-in blade fuse is wrapped around the fuse blade at least once.

[0055] In one or more embodiments of the secondary battery cell, the conductive ribbon of each built-in blade fuse is wrapped around the current collector more than once.

[0056] In one or more embodiments of the secondary battery cell, a dielectric layer is further included applied over the conductive tape.

[0057] In one or more embodiments of the secondary battery cell, the dielectric layer is a thermal insulation layer.

[0058] In certain aspects, the present disclosure relates to a method for manufacturing a secondary battery cell having an internal core contained within a container, the internal core including a plurality of current collectors, each current collector having a tab positioned within the container. The method includes: providing, for each fuse tab, an integral tab portion integral with a corresponding one of the current collectors; providing a separate tab component separated from the integral tab portion by a gap; and forming a built-in tab fuse that extends across the gap and electrically connects the integral tab portion and the separate tab component.

[0059] In one or more embodiments of the method, forming the built-in blade fuse includes securing a conductive tape to each of the integral blade portion and the separate blade component.

[0060] In one or more embodiments of the method, the conductive strap includes a positive temperature coefficient material.

[0061] In one or more embodiments of the method, the conductive tape of each internal blade fuse is provided in at least two layers.

[0062] In one or more embodiments of the method, the conductive tape of each internal blade fuse is wrapped around the fuse blade at least once.

[0063] In one or more embodiments of the method, the conductive tape of each internal blade fuse is wrapped around the current collector more than once.

[0064] In one or more embodiments of the method, the method further includes selecting a gap based on a maximum current that the fusible insert is designed to accommodate.

[0065] In one or more embodiments of the method, each fusible blade has a width, and the length of the built-in blade fuse in the width direction of the fusible blade is less than the width.

[0066] In one or more embodiments of the method, each fusible blade has a width, and at least a portion of the internal blade fuse has a length extending in a direction of the width of the fusible blade that is the same as the width.

[0067] In one or more embodiments of the method, further comprising applying a dielectric layer over the conductive tape.

[0068] In certain aspects, the present disclosure relates to a method for designing an internal fuse tab for a secondary battery, wherein the fuse tab includes a built-in tab fuse and has an integral tab portion and a separate tab component. The method includes determining a maximum design current; determining electrical characteristics of a conductive tape; and based on the maximum design current: selecting a gap width between the integral tab portion and the separate tab component to define a melting region for the conductive tape; and selecting an amount of conductive tape disposed in the melting region such that, when the conductive tape is disposed across the gap width, the conductive tape melts when a current flowing in the fuse tab exceeds the maximum design current.

[0069] Various modifications and additions may be made without departing from the spirit and scope of the present disclosure. The features of each of the various embodiments described above may be appropriately combined with the features of the other described embodiments to provide a variety of feature combinations in associated new embodiments. Furthermore, although the foregoing describes a plurality of separate embodiments, what is described herein merely illustrates the application of the principles of the present invention. Furthermore, although the specific methods herein may be illustrated and / or described as being performed in a particular order, it is within the skill of the art that the ordering is highly variable to implement aspects of the present disclosure. Accordingly, this description is meant to be taken as an example only and does not otherwise limit the scope of the present invention.

[0070] Exemplary embodiments have been disclosed above and shown in the accompanying drawings. Those skilled in the art will appreciate that various changes, omissions, and additions may be made to the specific disclosure herein without departing from the spirit and scope of the present invention.

Claims

1. A secondary battery cell comprising: container; An internal core located in the container includes a plurality of current collectors and a plurality of fuse inserts corresponding to the plurality of current collectors, wherein each fuse insert includes: an integral tab portion directly connected to a corresponding one of the current collectors and composed of a first conductive material; a separate tab member spaced from the integral tab portion to define a gap therebetween, the separate tab member being comprised of a second electrically conductive material; and A built-in blade fuse includes a third conductive material that is different from each of the first conductive material and the second conductive material and spans the gap to electrically connect the integral blade portion and the independent blade component to each other and define a melt zone between the integral blade portion and the independent blade component. 2 . The secondary battery cell according to claim 1 , wherein the built-in blade fuse includes a dielectric component that physically connects the integrated blade portion and the independent blade component to each other, wherein the third conductive material is applied to at least the dielectric component. The secondary battery cell according to claim 2 , wherein the dielectric component comprises a dielectric tape. The secondary battery cell according to claim 2 , wherein the third conductive material comprises tin. The secondary battery cell according to claim 2 , wherein the third conductive material comprises silver. 6 . The secondary battery cell according to claim 1 , wherein the first conductive material, the second conductive material, and the third conductive material each have electrical conductivity, and the electrical conductivity of the third conductive material is smaller than that of each of the first conductive material and the second conductive material. 7 . The secondary battery cell according to claim 6 , wherein the first conductive material and the second conductive material are both metals, and the third conductive material is a semiconductor. 8 . The secondary battery cell of claim 1 , wherein the built-in blade fuse comprises a conductive tape physically connecting the integral blade portion and the independent blade component to each other.

9. The secondary battery cell according to claim 1, wherein Each of the fusible inserts is a cathode insert.

10. The secondary battery cell according to claim 1, wherein Each of the fusible inserts is an anode insert. 11 . The secondary battery cell according to claim 1 , wherein the first conductive material is a first metal, the second conductive material is a second metal, and the third conductive material is a third metal different from each of the first metal and the second metal. 12 . The secondary battery cell of claim 11 , wherein the third conductive material comprises tin. 13 . The secondary battery cell according to claim 12 , wherein the first conductive material and the second conductive material each comprise copper. 14 . The secondary battery cell according to claim 12 , wherein the first conductive material and the second conductive material each comprise aluminum. 15 . The secondary battery cell of claim 11 , wherein the third conductive material comprises silver. 16 . The secondary battery cell according to claim 15 , wherein the first conductive material and the second conductive material each comprise copper. 17 . The secondary battery cell according to claim 15 , wherein the first conductive material and the second conductive material each comprise aluminum.

18. A secondary battery cell comprising: container; An internal core located within the container, comprising a plurality of current collectors and a plurality of fusible inserts corresponding to the plurality of current collectors, wherein each fusible insert is designed and configured not to melt under an operating current, and each fusible insert comprises: a built-in blade fuse designed and configured to melt at a predetermined excess current greater than each of the operating currents; and Dielectric tape, which is applied to the built-in blade fuse. 19 . The secondary battery cell according to claim 18 , wherein each fuse tab has a transverse cross-sectional area, and each corresponding built-in tab fuse is formed by reducing the transverse cross-sectional area in a region of the fuse tab. 20 . The secondary battery cell according to claim 18 , wherein the dielectric tape is wrapped around the built-in blade fuse at least once.

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