Abstract:
Lithium-ion batteries, unlike other chemistries, may need the voltage of every cell monitored. This may employ a wiring harness or interconnect board that connects the leads of each cell to battery monitoring electronics. These leads can be protected from each other by one or more methods including physical segregation, insulation, and fusing. If a fuse is used it can be located as close as possible to the terminal of the cell. The fuse can be located inside the sealed compartment of the cell itself. The leads would be passed out of the cell in a second location allowing the use of alternative sense lead wiring harnesses or interconnect board designs that save on packaging cost and volume. By locating the fuse inside the cell, design and validation efforts involved in placing a fuse inline with the wiring harness are eliminated.

Description:
FIELD OF THE INVENTION 
       [0001]    The present technology relates to lithium-ion batteries, including fusing to mitigate the effects of short-circuiting. 
       BACKGROUND OF THE INVENTION 
       [0002]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0003]    A lithium-ion battery includes a negative electrode, a positive electrode, and a separator there between. When the battery is charging, positively charged lithium ions move through an electrolyte from the positive electrode (cathode) to the negative electrode (anode), and in the opposite direction when the battery is discharging. The electrolyte can include a lithium salt, such as LIPF 6 , dissolved in an organic solvent, such as a mixture of linear and cyclic carbonate solvents. 
         [0004]    Lithium-ion battery technology is used in many electrical devices including hybrid and electric vehicles. Batteries based on lithium-ion chemistry can be lighter than batteries based on nickel metal hydride and lead acid. Because an energy density of a lithium-ion battery can be higher than other battery types, lithium-ion batteries can boost both the range and power of hybrid and electric vehicles. 
         [0005]    However, abusive electrical, thermal, or mechanical conditions can cause a lithium-ion battery to undergo self-heating and/or form ruptures in packaging, which can lead to incidents of undesirable performance. For example, abusive electrical conditions include overcharging the battery. Lithium-ion batteries can consequently cease functioning when subjected to high temperatures that may result from the abusive electrical conditions. These conditions can spread to adjacent cells. 
         [0006]    Accordingly, the charge of a lithium ion battery can be monitored at any given time to ensure proper operation and use of the battery, for example, as the battery goes through various charging and discharging cycles. In this way, overcharging of the battery and high temperatures associated therewith can be mitigated. Monitoring can also help to manage and optimize the useful lifespan of the battery and can serve as an indicator for timely replacement of a battery that may be approaching the end of its service life. 
       SUMMARY OF THE INVENTION 
       [0007]    The present technology includes systems, processes, articles of manufacture, and compositions that relate to a battery having an internal overcurrent protection device within the sealed battery cell, where the device protects a sensing lead running to a battery monitoring system. 
         [0008]    In some embodiments, a battery comprises a container, an electrode assembly, a first tab, a first overcurrent protective device, and a first lead. The electrode assembly is disposed within the container and includes a first electrode. The first tab is electrically coupled to the first electrode and the first tab traverses the container. The first overcurrent protective device is disposed within the container and is electrically coupled to the first electrode. The first lead is electrically coupled to the first overcurrent protective device and traverses the container. 
         [0009]    In some embodiments, a lithium-ion battery is provided. The lithium-ion battery includes a container comprising a flexible, hermetically sealed pouch. An electrolyte is disposed within the container, where the electrolyte includes a lithium salt and an organic solvent. An electrode assembly is disposed within the container, the electrode assembly has a first electrode, a second electrode, and a separator disposed between the first and second electrodes. A first tab is electrically coupled to the first electrode and traverses the container. A second tab is electrically coupled to the second electrode and traverses the container. A first overcurrent protective device is disposed within the container and is electrically coupled to the first electrode. A second overcurrent protective device is also disposed within the container and is electrically coupled to the second electrode. A first lead is electrically coupled to the first overcurrent protective device and traverses the container. And a second lead is electrically coupled to the second overcurrent protective device and also traverses the container. 
         [0010]    In some embodiments, a method of protecting a battery monitoring system is provided. The method includes interrupting an electrical current between a battery and the battery monitoring system using a first overcurrent protective device disposed within the battery. The battery used in the method can include embodiments of the batteries described herein. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The drawing described herein is for illustrative purposes only of selected embodiments and not all possible implementations, and is not intended to limit the scope of the present disclosure. 
           [0013]    The drawing depicts a fragmentary top plan view of a battery in accordance with an embodiment of the present technology. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The following description of technology is merely exemplary in nature of the subject matter, manufacture and use of one or more inventions, and is not intended to limit the scope, application, or uses of any specific invention claimed in this application or in such other applications as may be filed claiming priority to this application, or patents issuing therefrom. Regarding the methods disclosed, the order of the steps presented is exemplary in nature, and thus, the order of the steps can be different in various embodiments. 
         [0015]    The voltage of every cell in a lithium-ion battery can be monitored by using leads, a wiring harness, and/or an interconnect board that connects electrode plates or terminals or tabs of each cell to battery monitoring electronics. Leads can be protected from each other in one or more ways, including physically segregating, insulating, and/or equipping the leads with a fuse. In some cases, when the fuse is used, it can be located as close as possible to the electrode plates of the cell. 
         [0016]    The present technology includes locating a fuse for a sensing lead inside a sealed compartment of a battery. The sensing leads can be passed out of the battery in various locations to allow coupling with various sensing lead wiring harnesses or interconnect board designs. In this manner, the sensing leads, wiring harnesses, or interconnect boards do not require a fuse, which can save on packaging cost and volume. By locating the fuse inside the cell, design and validation efforts involved in placing a fuse inline with the sensing lead, wiring harness, or the interconnect board are eliminated. Batteries made in any configuration can benefit from this design. 
         [0017]    The drawing illustrates a lithium ion battery  100  that may be used in vehicle applications. The battery  100  includes an electrode assembly  105  and a container  110 , which can be formed with an interior region  115  for receiving the electrode assembly  105 . Components of the electrode assembly  105  and container  110  are illustrative of the basic components of the battery  100 , which can assume various sizes, shapes, and forms, and are not intended to be restricted to any particular orientation or scale as shown in the drawing. 
         [0018]    As shown, the electrode assembly  105  includes a first electrode  120 , a second electrode  125 , and a separator  130  arranged between the first and second electrodes  120 ,  125 . The separator  130  prevents a short circuit between the first and second electrodes  120 ,  125  and allows lithium ions to pass through therethrough. The electrode assembly  105  can be formed by winding the first electrode  120 , the separator  130 , and the second electrode  125  into a spiral or jelly roll type structure. Alternatively, as shown in the drawing, the first electrode  120 , the separator  130 , and the second electrode  125  can be sequentially laminated into a stacked structure. The first electrode  120  can be a negative electrode, while the second electrode  125  can be a positive electrode, although the reverse arrangement is contemplated. An electrolyte  135  can be introduced within the interior region  115  of the container  110  and the container  110  can be sealed. 
         [0019]    A first tab  140  and a second tab  145  are electrically connected to the respective first and second electrodes  120 ,  125  of the electrode assembly  105 . The first and second tabs  140 ,  145  can be configured wherein portions are be exposed outside of the container  110 . For example, the tabs  140 ,  145  can traverse the container  110 , where the tabs  140 ,  145  pass through a boundary defined by the container  110  such as a side of the container  110 . The portions exposed outside of the container can operate as terminals for the battery  100 . Portions of the first and second electrode tabs  140 ,  145  that come in contact with the container  110  can be insulated, for example by a wrap of an insulating tape (not shown). The embodiment of the container  110  shown in the drawing includes four sides, where the first and second tabs  140 ,  145  exit the same side of the container  110 . However, it is contemplated that the tabs  140 ,  145  can have different orientations and can exit the container  110  on different sides and in different directions, including opposite directions, and that the container  110  may assume various shapes, including shapes having circular or various polygonal cross-sections. 
         [0020]    In some embodiments, the first electrode  120 , the second electrode  125 , and the separator  130  form a single cell in the electrode assembly  105  of the battery  100  as shown in the drawing. However, the electrode assembly  105  can include a plurality of such cells where the respective negative electrodes are electrically coupled and the respective positive electrodes are electrically coupled (not shown). For example, multiple electrodes of multiple cells can be connected using an interconnecting member or internal weld plate (not shown). The interconnecting member or internal weld plate can form a portion of the respective tabs  140 ,  145  or can be electrically connected to the tabs  140 ,  145 . In this manner, the electrode assembly  105  of the battery  100  can include a plurality of cells connected in parallel. 
         [0021]    Monitoring of the electrode assembly  105  within the container  110  of the battery  100  can be accomplished using a first lead  150  and a second lead  155  that are connected to the first and second electrodes  120 ,  125 . As shown in the drawing, the first and second leads  150 ,  155  extend between the exterior and the interior of the container  110 , and include a first overcurrent protective device  160  and a second overcurrent protective device  165  such as fuses disposed therein. The leads  150 ,  155  can traverse the container  110  via one or more passthroughs that are located on the container  110  where desired. The first and second overcurrent protective devices  160 ,  165  are shown coupled to the first and second tabs  140 ,  145 , but the overcurrent protective devices  160 ,  165  can be coupled directly to the first and second electrodes  120 ,  125 . The first and second leads  150 ,  155  can be used to sense and monitor a charge state of the battery  100  and can be coupled to a battery monitoring system (not shown) that regulates a charge/discharge of the battery through the tabs  140 ,  145 . 
         [0022]    As shown, the leads  150 ,  155  are on the same side of the container  110  and are adjacent to the tabs  140 ,  145 . However, it is contemplated that the leads  150 ,  155  can have different orientations and can exit different sides of the container  110 , including opposite sides. The leads  150 ,  155  can also exit the container  110  from a different side or direction than the tabs  140 ,  145 . For example, the first and second tabs  140 ,  145  can exit the pouch in different directions from each other (e.g., opposite ends) while the first and second leads  150 ,  155  can exit the pouch perpendicular to the tabs  140 ,  145 . 
         [0023]    The first electrode  120  can be formed by coating a shaped metal plate such as a negative collector with a negative active material. The metal plate can comprise a copper film or foil while the negative active material can be formed from a carbon material as a main component along with a binder and a conductive material. The first electrode  120  is electrically connected to the first tab  140 . 
         [0024]    The second electrode  125  can be formed by coating a shaped metal plate such as a positive collector with a positive active material. The metal plate can comprise an aluminum film or foil while the positive active material can be formed from a lithium based oxide as a main component along with a binder and a conductive material. The second electrode  125  is electrically connected to the second tab  145 . 
         [0025]    The separator  130  can include a polyethylene film, a polypropylene film, or a combination thereof. The separator  130  can be formed to be wider than the first and second electrodes  120 ,  125  as shown in the drawing to prevent a short circuit between the first and second electrodes  120 ,  125 , although other configurations can be used. 
         [0026]    The electrolyte  135  can include a liquid comprising one or more lithium salts such as LiPF 6 , LIBF 4 , and LiClO 4  and an organic solvent such as a carbonate, including mixtures of linear and/or cyclic carbonates. The electrolyte  135  conducts lithium ions which act as a carrier between the first electrode  120  and the second electrode  125  when the lithium ion battery  100  passes an electric current through an external circuit. 
         [0027]    The container  110  is formed from a wide variety of materials including materials that can be both flexible and heat sealable wherein no gas or liquid may leave or enter the battery  100 . For example, the container  110  can include a pouch comprising a laminate material of aluminum and plastic that is heat sealable. The container  110  can be hermetically sealed and the passthrough locations of any components of the battery  100  that traverse the container  110 , such as tabs  140 ,  145  and leads  150 ,  155 , can maintain the hermetic seal of the container  110 . 
         [0028]    Both the first electrode  120  and the second electrode  125  are materials into which and from which lithium can migrate. When a cell is discharging, lithium is extracted from the negative electrode (e.g., the first electrode plate  120 ) and inserted into the positive electrode (e.g., the second electrode plate  125 ). When the cell is charging, the reverse process occurs, where lithium is extracted from the positive electrode (e.g., the second electrode plate  125 ) and inserted into the negative electrode (e.g., the first electrode plate  120 ). 
         [0029]    The first and second leads  150 ,  155  can comprise an electrically conductive material that can be insulated, particularly where the leads  150 ,  155  traverse the container  110 . For example, the leads  150 ,  155  can include about 0.2 mm nickel foil or similar wire. The leads  150 ,  155  can be coupled to a battery monitoring system (not shown) for measuring the voltage of the lithium ion battery  100 . In this manner, the battery monitoring system can be used to regulate charging and/or discharging of the battery  100  and can mitigate overcharging and other adverse electrical conditions that may impact the battery  100 . 
         [0030]    The first overcurrent protective device  160  and the second overcurrent protective device  165  are configured to interrupt electrical current through the respective leads  150 ,  155  and can comprise a sacrificial device such as a fuse or switchable device such as a circuit breaker. In this fashion, the overcurrent protective devices  160 ,  165  can protect the battery monitoring system from excessive current that may be caused by abusive electrical, thermal, or mechanical conditions experienced by the battery. The battery monitoring system can also be configured to sense when one or both overcurrent protective devices  160 ,  165  have interrupted electrical current through the leads  150 ,  155 . In some embodiments, the overcurrent protective devices  160 ,  165  can include an element made of copper, silver, aluminum, zinc, or alloys thereof that provides stable and predictable characteristics. The overcurrent protective devices  160 ,  165  can be configured to carry a particular current and quickly interrupt the current upon experiencing a current excess. However, the overcurrent protective devices  160 ,  165  can be designed so that current is not interrupted when only minor surges of current are experienced. 
         [0031]    In some embodiments, the overcurrent protective devices  160 ,  165  each include a fuse that can be a surface mountable part or fusible trace on a flexible printed circuit board (FPCB). The FPCB can be placed within the interior  115  of the battery  100  and a portion of the FPCB can be affixed to an edge when the container  110  of the battery  100  is sealed during fabrication, for example. The FPCB can be in electrical communication with the exterior of the battery  100 , for example, by using the leads  150 ,  155  as shown. Locating the overcurrent protective devices  160 ,  165  at an edge of the container  110  prevents interference with the electrodes  120 ,  125  and separator  130  of the electrode assembly  105 . The FPCB can have a conductive connection to one of the electrodes  120 ,  125 , one of the tabs  140 ,  145 , or an interconnecting member or cell internal weld where multiple electrodes in a multicell battery are connected (not shown). Another conductive connection can be made from the FPCBs to the leads  150 ,  155 . 
         [0032]    The present technology provides several benefits to increase durability, quality, and function across different battery systems. The benefits include minimizing the cost of validation for battery and monitoring system designs, minimizing a volume and configuration of the system, and optimizing battery monitoring. For example, battery and monitoring system layouts can change frequently for a given system and/or vehicle design, but basic battery cell design does not change as frequently. Accordingly, by integrating an overcurrent protection device into the battery, it eliminates part of the design work in connecting a monitoring system to each new battery concept while retaining a validated and durable sensing line monitoring connection. 
         [0033]    Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Equivalent changes, modifications and variations of some embodiments, materials, compositions and methods can be made within the scope of the present technology, with substantially similar results.