Battery cell terminal with integrated circuit protection

Abstract

The invention provides a battery cell terminal with integrated circuit protection. A battery cell includes: a housing; a current collector having a main body disposed in the housing and a terminal substrate extending from the housing and defining a cutout; and a conductive filler material. The conductive filler material is disposed within the cutout and cooperates with the substrate to form a terminal configured to connect with a load. The filler material has a lower melting point than the substrate, and further mates with the substrate such that an electrical flux flows through both the substrate and the filler material when the temperature of the terminal is below the melting point of the filler material, and the electrical flux flows through both the substrate and the filler material when the temperature of the terminal exceeds the melting point of the filler material. The electric flux only flows through the substrate.

Description

Technical Field

[0001] The present disclosure relates to battery cells, and more particularly, to terminals with integrated circuit protection. Background Art

[0002] Vehicles such as battery electric vehicles and hybrid electric vehicles may contain a battery assembly to serve as an energy source for the vehicle. The battery assembly may include a plurality of battery cells connected in series, in parallel, or in a combination thereof. Each battery cell may include one or more terminals for connecting the individual battery cells to a load. Summary of the invention

[0003] According to one embodiment, a battery cell includes: a body; an active battery material disposed within the body; and a terminal extending from the body and including a first end connected to the active battery material and a second end connectable to a load. A first material forms a first portion of the terminal and defines a first electrical path between the first end and the second end, and a second material forms a second portion of the terminal and defines a second electrical path between the first end and the second end. The second material has a lower melting point than the first material, so that the second electrical path is disconnected in response to the temperature of the terminal exceeding the melting point of the second material, thereby causing the first path to carry all the current of the load.

[0004] According to another embodiment, a battery cell includes: a body; a discrete first material and a second material having different melting points, the discrete first material and the second material being joined together to form a terminal. The terminal has a first end disposed within the body and a second end external to the body and connectable to a load. The first material is continuous between the first end and the second end, and the second material is accommodated to a middle portion of the terminal. When the temperature of the terminal is below a threshold, the middle portion has a first cross-sectional area formed by both the first material and the second material, and a second smaller cross-sectional area formed only by the continuous portion of the first material when the temperature of the terminal exceeds the threshold.

[0005] According to yet another embodiment, a battery cell includes: a housing; a current collector having a body disposed in the housing and a terminal substrate extending from the housing and defining a cutout; and a conductive filler material. The conductive filler material is disposed within the cutout and cooperates with the substrate to form a terminal configured to be connected to a load. The filler material has a lower melting point than the substrate and further cooperates with the substrate so that when the temperature of the terminal is below the melting point of the filler material, an electric flux flows through both the substrate and the filler material, and when the temperature of the terminal exceeds the melting point of the filler material, the electric flux flows only through the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic diagram of an example hybrid vehicle.

[0007] Figure 2 is a perspective view of an example battery cell.

[0008] Figure 3 is a schematic cross-sectional view of an example battery cell.

[0009] Figure 4A Terminals of a current collector according to an embodiment are shown.

[0010] Figure 4B Shows Figure 4A of the terminals after the first temperature threshold has been exceeded.

[0011] Figure 4C Shows Figure 4A The terminals after having exceeded the second temperature threshold resulting in a short circuit.

[0012] Figure 5A A terminal of a current collector according to another embodiment is shown.

[0013] Figure 5B Shows Figure 5A of the terminals after the first temperature threshold has been exceeded.

[0014] Figure 5C Shows Figure 5A The terminals after having exceeded the second temperature threshold resulting in a short circuit.

[0015] Fig. 6A A terminal of a current collector according to yet another embodiment is shown.

[0016] Figure 6B Shows Fig. 6A of the terminals after the first temperature threshold has been exceeded.

[0017] Figure 6C Shows Fig. 6AThe terminals after having exceeded the second temperature threshold resulting in a short circuit. DETAILED DESCRIPTION

[0018] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take on various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show the details of a particular component. Therefore, the specific structural details and functional details disclosed herein are not to be interpreted as limiting, but only as a representative basis for teaching those skilled in the art to adopt the present invention in various ways. As will be understood by those of ordinary skill in the art, the various features shown and described with reference to any one of the drawings may be combined with the features shown in one or more other drawings to produce embodiments that are not explicitly shown or described. The combination of features shown provides representative embodiments for typical applications. However, for specific applications or embodiments, various combinations and modifications of features consistent with the teachings of the present disclosure may be desired.

[0019] Figure 1 A schematic diagram of a plug-in hybrid electric vehicle (PHEV) is depicted. However, certain embodiments may also be implemented in the context of non-plug-in hybrid and pure electric vehicles. Vehicle 12 includes one or more electric machines 14 mechanically connected to a hybrid transmission 16. Electric machine 14 may be capable of acting as a motor or a generator. In addition, hybrid transmission 16 may be mechanically connected to engine 18. Hybrid transmission 16 may also be mechanically connected to drive shaft 20, which is mechanically connected to wheels 22. Electric machine 14 may provide propulsion and deceleration capabilities when engine 18 is turned on or off. Electric machine 14 also acts as a generator and may provide fuel economy benefits by recovering energy through regenerative braking.

[0020] The battery pack 24 stores energy that can be used by the electric machine 14. The battery pack 24 generally provides a high voltage direct current (DC) output from one or more battery cell arrays (sometimes referred to as battery cell stacks) within the battery pack 24. A battery cell array includes one or more battery cells.

[0021] A battery cell (such as a prismatic, pouch, cylindrical, or any other type of cell) converts stored chemical energy into electrical energy. A battery cell may include a housing, a positive electrode (cathode), and a negative electrode (anode). An electrolyte allows ions to move between the anode and cathode during discharge and then back during recharge. Terminals may allow current to flow out of the cell for use in a vehicle.

[0022] Different battery pack configurations can be used to meet various vehicle variables, including packaging constraints and power requirements. Thermal management systems can be used to thermally regulate the battery cells. Examples of thermal management systems include: air cooling systems, liquid cooling systems, and combinations of air and liquid systems.

[0023] The battery pack 24 can be electrically connected to one or more power electronic modules 26 through one or more contactors (not shown). One or more contactors isolate the battery pack 24 from other components when disconnected, and connect the battery pack 24 to other components when closed. The power electronic module 26 can be electrically connected to the motor 14, and can provide the ability to transfer electrical energy bidirectionally between the battery pack 24 and the motor 14. For example, a typical battery pack 24 can provide a DC voltage, while the motor 14 may require a three-phase alternating current (AC) voltage to work. The power electronic module 26 can convert the DC voltage into a three-phase AC voltage according to the needs of the motor 14. In regenerative mode, the power electronic module 26 can convert the three-phase AC voltage from the motor 14 acting as a generator into the DC voltage required by the battery pack 24. The description herein is also applicable to pure electric vehicles. In pure electric vehicles, the hybrid transmission 16 may be a gearbox connected to the motor 14, without the presence of the engine 18.

[0024] In addition to providing energy for propulsion, the battery pack 24 can also provide energy for other vehicle electrical systems. A typical system may include a DC / DC converter module 28 that converts the high voltage DC output of the battery pack 24 into a low voltage DC supply compatible with other vehicle components. Other high voltage loads (such as compressors and electric heaters) can be connected directly to the high voltage supply without using the DC / DC converter module 28. In a typical vehicle, the low voltage systems are electrically connected to an auxiliary battery 30 (e.g., a 12 volt battery).

[0025] A battery energy control module (BECM) 33 may communicate with the battery pack 24. The BECM 33 may act as a controller for the battery pack 24 and may also include an electronic monitoring system that manages the temperature and state of charge of each of the battery cells. The battery pack 24 may have a temperature sensor 31, such as a thermistor or other thermometer. The temperature sensor 31 may communicate with the BECM 33 to provide temperature data about the battery pack 24.

[0026] The vehicle 12 may be recharged by a charging station connected to an external power source 36. The external power source 36 may be electrically connected to an electric vehicle supply equipment (EVSE) 38. The external power source 36 may provide DC or AC power to the EVSE 38. The EVSE 38 may have a charging connector 40 for plugging into a charging port 34 of the vehicle 12. The charging port 34 may be any type of port configured to transfer power from the EVSE 38 to the vehicle 12. The charging port 34 may be electrically connected to a charger or an onboard power conversion module 32. The power conversion module 32 may condition the power supplied from the EVSE 38 to provide the appropriate voltage and current levels to the battery pack 24. The power conversion module 32 may interface with the EVSE 38 to coordinate power delivery to the vehicle 12. The EVSE connector 40 may have pins that mate with corresponding recesses of the charging port 34.

[0027] The various components discussed may have one or more associated controllers to control and monitor the operation of the components. The controllers may communicate via a serial bus (eg, a controller area network (CAN)) or via dedicated electrical conduits.

[0028] The battery pack 24 includes one or more battery arrays, each battery array having a plurality of battery cells arranged in a stack. Figure 2 An example battery cell 50 is shown in FIG. The cell may be a soft-pack cell, a square cell, a cylindrical cell, etc. The positive terminal 52 and the negative terminal 54 extend from the outer body or shell 55 of the cell 50. Each cell 50 may have two terminals, for example, where the positive terminal and the negative terminal extend from different sides (as shown) or extend on the same side. Typically, each cell has a cathode, an anode, a separator, and an electrolyte. Alternatively, the cell may have a solid electrolyte, wherein the solid electrolyte may act as a separator between the cathode and the anode. The positive terminal 52 is electrically connected to the cathode, and the negative terminal 54 is electrically connected to the anode. The anode and cathode may be referred to as electrodes.

[0029] Figure 3 6 is a cross-sectional view through an exemplary battery cell 50. The battery cell 50 includes a cathode current collector 62, an anode current collector 64, and an electrolyte 66. A separator (not shown) may be placed between the anode and the cathode. An active material 67 may be disposed on one or both sides of the cathode current collector 62, and an active material 69 may be disposed on one or both sides of the anode current collector 64. The active materials 67, 69 may include materials such as graphite or other carbon-based materials, silicon, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel manganese cobalt oxide, or combinations thereof.

[0030] The cathode current collector 62 may be formed of a metal such as aluminum and may include a terminal 63 (also referred to as a tab) that is a bare metal. The tab 63 protrudes from the body 68 of the cathode current collector 62 of the housing 55 that encloses the battery cell 50, as shown in FIG. Figure 2 Tab 63 forms a positive terminal that can be electrically connected to a load.

[0031] The anode current collector 64 may be formed of a metal such as copper and may include a bare metal terminal 65 (also referred to as a tab). The tab 65 protrudes from the body 71 of the current collector and may extend from the housing 55 enclosing the battery cell 50, as shown in FIG. Figure 2 Tab 65 forms a negative terminal that can be electrically connected to ground.

[0032] As will be described in detail below, one or more of the cell terminals may include an integrated circuit to passively control the flow of current therethrough. The circuit protection may be a quasi-integrated fuse. Unlike fuses having a narrowed cross-sectional area for carrying current, the terminals of the present disclosure maintain a full cross-sectional area during normal operation, so that the addition of circuit protection does not degrade performance compared to terminals with circuit protection.

[0033] The following figures and associated text describe example terminals that may be used in any of the above-described battery cells.

[0034] refer to FIG. 4A to FIG. 4C , the current collector 80 may have a body 82 and a terminal 84. The body 82 may be disposed in a housing that encloses the battery cell. The terminal 84 extends from a side 83 of the body 82 to the outside of the housing. The current collector 80 may be used for an anode or a cathode. The terminal 84 includes a substrate 86. The substrate 86 may be formed integrally with the body 82. The substrate 86 has a distal portion 90 and a proximal portion 92. The distal portion 90 may be connected to a load, and the proximal portion 92 is at the side 83 and at least partially located within the housing of the battery cell.

[0035] The substrate 86 includes opposing longitudinal sides 88, 89 extending between a distal portion 90 and a proximal portion 92. A pair of cutouts (e.g., slots 91, 93) are defined in the substrate 86. Each cutout 91, 93 extends inwardly from its associated longitudinal side. The cutouts 91, 93 are aligned with each other, i.e., located at the same longitudinal position, to form a bridge 94 between the cutouts 91, 93. In this example, the bridge 94 is a narrow metal strip that extends in the longitudinal direction of the terminal 84 and forms an electrical path between the proximal portion 92 and the distal portion 90. In the illustrated embodiment, the portions 90 and 92 and the bridge 94 are all integrally formed parts of the substrate 86.

[0036] The cutouts 91, 93 and the subsequently formed bridges 94 cause the substrate 86 to have different widths at different longitudinal locations. Because the substrate 86 can have a uniform thickness throughout, this produces different cross-sectional areas at different longitudinal locations of the substrate 86. In order to provide a full terminal width and cross-sectional area along the entire length of the terminal 84, a conductive filler material 95 is added to the cutouts 91, 93.

[0037] Filling material 95 may be disposed within the cutouts 91, 93, such as Figure 4A , and cooperates with the substrate 86 to form the terminal 84. That is, the terminal 84 is composed of the substrate 86 and the filling material 95 in at least one condition. The conductive filling material 95 can be a low melting point alloy (LMPA), such as bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium, thallium, or a combination thereof. The LMPA can have a melting point below 400°C.

[0038] When the temperature of the substrate 86 is lower than the melting point (first threshold temperature) of the conductive fill material 95, the electric flux flows through both the conductive fill material 95 and the bridge 94. Figure 4B As shown in , when the temperature of the terminal 84 exceeds the melting point of the filler material 95, the filler material 95 melts, leaving only the substrate 86 to carry all the current. The substrate 86 can be sized so that it alone can carry all the rated current. Therefore, all the electrical flux flows through the narrow bridge 94, which forms a circuit protector. If the temperature of the bridge 94 exceeds a second threshold, the bridge 94 melts, thereby electrically and physically disconnecting the distal end 90 from the proximal end 92, as shown in FIG. Figure 4C as shown in .

[0039] refer to FIG. 5A to FIG. 5C , another current collector 100 has a terminal 102 including a substrate 104. The substrate 104 includes opposite longitudinal sides 105, 106 extending between a distal portion 108 and a proximal portion 110. The substrate 104 defines a cutout 112, such as a hole. The hole 112 can be circular, rectangular, or other geometric shapes. The cutout 112 does not intersect the longitudinal sides 105, 106, but is completely surrounded by the substrate 104 to form narrowed portions 114, 115 adjacent to the cutout 112 along the longitudinal sides 105, 106. In this example, the narrowed portions 114, 115 are narrow metal strips that extend in the longitudinal direction of the terminal 102 and form an electrical path between the proximal portion 110 and the distal portion 108. In the illustrated embodiment, the distal portion 108, the proximal portion 110, and the narrowed portions 114, 115 are all integrally formed parts of the substrate 104.

[0040] Conductive fill material 116 may be disposed within cutout 112, such as Figure 5A, and cooperates with substrate 104 to form terminal 102. That is, terminal 102 is composed of substrate 104 and filling material 116 in at least one condition. As described above, when the temperature of substrate 104 is below the first threshold temperature, the electric flux flows through both the conductive filling material 116 and the narrowed portions 114, 115, and when the temperature of substrate 104 exceeds the first threshold temperature, the filling material 116 melts, leaving only substrate 104 to carry all the current, as shown in FIG. Figure 5B as shown in .

[0041] refer to FIG. 6A to FIG. 6C , another current collector 120 has a terminal 122 including a substrate 124. The substrate 124 includes opposing longitudinal sides 125, 126 extending between a distal portion 128 and a proximal portion 130. A pair of cutouts (e.g., slots 132, 133) are defined in the substrate 124. Each cutout 132, 133 extends inwardly from its associated longitudinal side. The cutouts 132, 133 are not aligned with each other, i.e., are not located at the same longitudinal position, to form a narrowing path 134 between the cutouts 132, 133. In this example, the narrowing path 134 is a narrow metal strip that extends in the longitudinal direction of the terminal 122 and forms an electrical path between the proximal portion 130 and the distal portion 128. In the illustrated embodiment, the portions 128 and 130 and the narrowing path 134 are all integrally formed parts of the substrate 124.

[0042] Conductive filling material 136 may be disposed within cutouts 132, 133, such as Fig. 6A , and cooperates with substrate 124 to form terminal 122. That is, terminal 122 is composed of substrate 124 and filling material 136 in at least one condition. As described above, when the temperature of substrate 124 is below the first threshold temperature, the electrical flux flows through both the conductive filling material 136 and the narrowed portion 134, and when the temperature of substrate 124 exceeds the first threshold temperature, the filling material 136 melts, leaving only substrate 124 to carry all the current, as shown in FIG. Figure 6B as shown in .

[0043] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive words rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously described, the features of various embodiments can be combined to form other embodiments of the present invention that may not be clearly described or shown. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it will be appreciated by those of ordinary skill in the art that one or more features or characteristics may be compromised to achieve the desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, strength, durability, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. For this reason, embodiments described as less desirable than other embodiments or prior art implementations in terms of one or more characteristics are within the scope of the present disclosure and may be desirable for specific applications.

[0044] According to the present invention, there is provided a battery cell having: a body; an active battery material disposed within the body; and a terminal extending from the body and comprising: a first end connected to the active battery material; a second end connectable to a load; a first material forming a first portion of the terminal and defining a first electrical path between the first end and the second end; and a second material forming a second portion of the terminal and defining a second electrical path between the first end and the second end; wherein the second material has a lower melting point than the first material, so that the second electrical path is disconnected in response to the temperature of the terminal exceeding the melting point of the second material, thereby causing the first path to carry all the current of the load.

[0045] According to an embodiment, the first material and the second material are joined to adhesively form the terminal.

[0046] According to an embodiment, the first material is configured to open the first electrical path in response to the temperature of the terminal exceeding the melting point of the first material to electrically disconnect the second end from the first end.

[0047] According to an embodiment, the first end and the second end are formed from the first material.

[0048] According to an embodiment, the terminal has a first width, and the first material includes a narrow portion having a second width smaller than the first width.

[0049] According to an embodiment, the second material is adjacent to the narrow portion such that a combined width of the narrow portion and the second material is equal to the first width.

[0050] According to an embodiment, the terminals are rectangular.

[0051] According to an embodiment, the second material is an alloy comprising one or more of: bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium or thallium.

[0052] According to an embodiment, the second material has a melting point less than or equal to 400 degrees Fahrenheit.

[0053] According to the present invention, a battery cell is provided, which has: a main body; a discrete first material and a second material with different melting points, the discrete first material and the second material are joined together to form a terminal, the terminal having a first end arranged in the main body and a second end outside the main body and connectable to a load, wherein the first material is continuous between the first end and the second end and the second material is accommodated to the middle part of the terminal, wherein when the temperature of the terminal is lower than a threshold value, the middle part has a first cross-sectional area formed by both the first material and the second material, and when the temperature of the terminal exceeds the threshold value, the middle part has a second smaller cross-sectional area formed only by the first material.

[0054] According to an embodiment, the first material is configured to create an open circuit between the first end and the second end at the middle portion in response to a temperature of the middle portion exceeding the melting point of the first material.

[0055] According to an embodiment, the second material is arranged on opposite sides of the first material at the middle portion.

[0056] According to an embodiment, the first material is copper or aluminum.

[0057] According to an embodiment, the second material is an alloy comprising one or more of: bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium or thallium.

[0058] According to an embodiment, the second material has a melting point less than or equal to 400 degrees Fahrenheit.

[0059] According to the present invention, there is provided a battery cell comprising: a shell; a current collector having a main body arranged in the shell and a terminal substrate extending from the main body and outside the shell, wherein the substrate defines a cutout; and a conductive filling material, the conductive filling material being arranged in the cutout and cooperating with the substrate to form a terminal configured to be connected to a load, wherein the filling material has a lower melting point than the substrate, and wherein the filling material cooperates with the substrate so that when the temperature of the terminal is lower than the melting point of the filling material, an electric flux flows through both the substrate and the filling material, and so that when the temperature of the terminal exceeds the melting point of the filling material, the electric flux flows only through the substrate.

[0060] According to an embodiment, the base plate has a distal end and a proximal end connected by a bridge, and wherein one side of the bridge forms one side of the cutout.

[0061] According to an embodiment, the cutout is a first cutout and the substrate further defines a second cutout, wherein the first cutout and the second cutout are located on opposite sides of the substrate.

[0062] According to an embodiment, the terminal substrate has opposite longitudinal sides and the cutout is a hole between the opposite sides.

[0063] According to an embodiment, the filling material is an alloy comprising one or more of: bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium or thallium.

Claims

1. A battery cell, comprising: Car body; an active battery material disposed within the body; as well as a terminal extending from the body and comprising: a first end connected to the active battery material, a second terminal, the second terminal being connectable to a load, a first material forming a first portion of the terminal and defining a first electrical path between the first end and the second end, and a second material forming a second portion of the terminal and defining a second electrical path between the first end and the second end; in The second material has a lower melting point than the first material such that the second electrical path opens in response to the temperature of the terminal exceeding the melting point of the second material, thereby causing the first path to carry all current of the load.

2. The battery cell of claim 1, wherein the first material and the second material are joined to adhesively form the terminal.

3. The battery cell of claim 1, wherein the first material is configured to open the first electrical path in response to a temperature of the terminal exceeding the melting point of the first material to electrically disconnect the second end from the first end.

4. The battery cell of claim 1, wherein the first end and the second end are formed from the first material.

5. The battery cell of claim 1, wherein the terminal has a first width and the first material includes a narrow portion having a second width less than the first width.

6. The battery cell of claim 5, wherein the second material is adjacent to the narrow portion such that a combined width of the narrow portion and the second material is equal to the first width.

7. The battery cell of claim 6, wherein the terminals are rectangular.

8. The battery cell of claim 1, wherein the second material is an alloy comprising one or more of: bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium, or thallium.

9. The battery cell of claim 1, wherein the second material has a melting point less than or equal to 400 degrees Fahrenheit.

10. A battery cell, comprising: main body; as well as A discrete first material and a second material having different melting points, the discrete first material and the second material being joined together to form a terminal, the terminal having a first end disposed within the body and a second end external to the body and connectable to a load, wherein the first material is continuous between the first end and the second end and the second material is accommodated to a middle portion of the terminal, wherein when the temperature of the terminal is below a threshold, the middle portion has a first cross-sectional area formed by both the first material and the second material, and when the temperature of the terminal exceeds the threshold, the middle portion has a second smaller cross-sectional area formed by only the first material.

11. The battery cell of claim 10, wherein the first material is configured to create an open circuit between the first end and the second end at the middle portion in response to a temperature of the middle portion exceeding the melting point of the first material.

12. The battery cell of claim 10, wherein the second material is disposed on opposite sides of the first material at the intermediate portion.

13. The battery cell of claim 10, wherein the first material is copper or aluminum.

14. The battery cell of claim 13, wherein the second material is an alloy comprising one or more of: bismuth, gallium, tin, indium, zinc, cadmium, tellurium, niobium, or thallium.

15. The battery cell of claim 10, wherein the second material has a melting point less than or equal to 400 degrees Fahrenheit.

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